Sustainable Innovative Design of Elderly-Friendly Smart Medical Products: An Integrated Model

Abstract

Under the promotion of combined medical and elderly care (CMEC) policies, the market demand for elder-friendly smart medical products as convenient intelligent healthcare devices is growing. However, most studies on elderly-friendly smart medical products focus on functional enhancement and cost control, and there is a lack of research on the sustainable innovative design of elder-friendly smart medical products from the perspective of elderly emotional needs. Therefore, this paper proposes an integrated framework based on the fuzzy Kano model, Kansei engineering, and theory of inventive problem solving (TRIZ) for mapping the complex and dynamic emotional needs of the elderly to product design parameters to produce innovative solutions, ensuring the sustainability of the design process and the innovativeness of the design solutions of elder-friendly smart medical devices. We verified the effectiveness and applicability of this integrated framework through a case study involving sustainable innovation design of a smart blood pressure device. The results of this study are of considerable theoretical and practical significance for promoting the development of the market for elder-friendly smart medical products under the policy of CMEC, meeting the needs of the elderly for healthcare devices and improving their quality of life.

1. Introduction

Combined medical and elderly care (CMEC) is an important means of achieving the goals of a healthy China, and active aging and is also necessary for the high-quality development of the elderly care system [1]. With the continuous interaction and integration of population aging, digitalization, and intelligence, elder-friendly smart medical products have broken through the time and space limitations of conventional medical care using advanced information technology and artificial intelligence algorithms, expanding the scope and methods of medical services, and have enabled smart interactions in various aspects, such as remote medical care and health management, personalized medical care, precision diagnosis and treatment, and medical information sharing and collaborative work [2]. These products have gradually provided a critical support and interactive interface in the promotion of the development of CMEC [3]. Considering the current dominant position of China’s home care model [4], elder-friendly smart medical products also play a pivotal role in replacing professional caregiving or unattended care.

However, the current research and design of elder-friendly smart medical products are still in the development stage. Although the overall device designs meet the core functional needs of the elderly, there are common issues such as complex operating procedures, multilayer interfaces, and iterative system updates, which cause conflicts between the product design and the emotional needs of the elderly [5,6]. In fact, with the improvement in quality of life for the elderly population and the increase in the requirements for personalization, their requirements regarding medical products are no longer limited to the product appearance but are more focused on the emotional experience and the satisfaction of the potential needs [7]. Therefore, to provide the elderly with a more humanized and personalized care experience and to promote the construction of a multilayer, high-quality elderly care service system, it is important to optimize the design of elder-friendly smart medical products [4].

Sociocultural changes and the decline in all aspects of physiological function have contributed to the complex and changing emotional needs of the elderly [8]. For elder-friendly smart medical products to meet the ever-changing emotional needs of the elderly, it is necessary to achieve sustainable innovative design of the products [9,10]. Unfortunately, the emotional needs of the elderly for smart healthcare products are often complex and ambiguous, making it difficult to accurately map the needs to the specific design parameters required by designers. In the design process, designers and engineers can only rely on subjective judgment and attempt to abstractly describe the design pattern of elder-friendly medical products under ideal conditions [11]. In this case, the design of elder-friendly smart medical products relies heavily on the tacit knowledge of the designers, and most designers exhibit knowledge-concealing behaviors and are constrained within the established design thinking, resulting in unsustainable product design and a lack of innovation [12]. Therefore, achieving an effective correlation between the design direction of elder-friendly smart medical products and the emotional needs of the elderly has become a key issue in the sustainable innovative design of elder-friendly smart medical products.

Reviewing the previous literature on elder-friendly smart medical products revealed that most scholars focused on using artificial intelligence technology, Internet of Things (IoT) technology, and smart sensor technology to enhance the functionality or reduce the production cost of elderly-friendly smart medical products [13,14,15,16]. However, there is a lack of a sustainable innovation design framework specifically aimed at meeting the emotional needs of the elderly in elder-friendly smart medical products.

The proposal of a sustainable innovation design framework for elder-friendly smart medical products is based on a thorough understanding of the emotional needs of the elderly. In this regard, Kansei engineering is currently a mainstream research method in the field of product design [17,18]. It primarily uses statistical analysis and data mining techniques to translate users’ emotional needs into quantifiable data, which in turn guides product design [19,20,21]. However, most research in Kansei engineering tends to emphasize the collection, processing, and analysis of emotional needs, and the final product design solutions primarily focus on addressing these emotional needs while often neglecting the importance of innovation in the solutions.

The theory of inventive problem solving (TRIZ), as a typical innovation methodology, provides a systematic and structured framework that transforms the innovation process into a fixed pattern, making the process more organized. This approach helps individuals and organizations break free from conventional thinking, lowers the threshold for innovation, and continuously drives the innovation process [22]. TRIZ has already seen widespread application in the field of product design, enabling innovative design across various product categories, such as medical devices [23], everyday household items [24], and industrial products [25]. However, research focusing on the application of TRIZ to solve product innovation issues in elder-friendly smart medical products, with an emphasis on user emotional needs, is lacking.

Given the advantages of both Kansei engineering and TRIZ, as well as the gaps identified in the existing literature, this study attempts to integrate Kansei engineering and TRIZ. This study starts by extracting user emotional needs for elder-friendly smart medical products using Kansei engineering and then applies TRIZ to propose innovative product design solutions based on these emotional needs, thereby forming a sustainable innovation design loop.

In addition, the semantic differential method in Kansei engineering is widely used due to its simplicity, low cost, high reliability and validity, and its ability to effectively quantify subjective evaluations [26]. For example, Ding and Bai [27] focused on the emotional needs of users regarding the color of thermos products, using the semantic differential method to identify five core words of emotional needs influencing user preferences, and proposed color design schemes for thermos products based on these words. Similarly, Cao et al. [28] applied the semantic differential method to identify core words of emotional needs from 60 preliminary words of emotional needs related to game icon design, which influenced the quality of emotional matching between game icons and users. They also suggested several schemes to improve the perceived quality of game icons. However, existing studies using the semantic differential method have not systematically classified the large set of preliminary words of emotional needs, leading to the final core words of emotional needs being associated with varying degrees of user satisfaction improvement, resulting in less significant satisfaction enhancement. The fuzzy Kano model excels in systematic classification and can effectively address this issue [29,30,31]. Therefore, this study attempts to integrate the fuzzy Kano model into the process of screening core words of emotional needs in the semantic differential method.

Finally, the present study focused on the emotional needs of the elderly. A methodological framework based on the fuzzy Kano model, Kansei engineering, and TRIZ is proposed to achieve sustainable innovative design of elderly-friendly smart medical products. First, the fuzzy Kano method is integrated into the semantic scale of Kansei engineering to scientifically explore the specific emotional needs of the elderly user group for elderly-friendly smart medical products and filter out the core emotional needs. Second, the core emotional needs obtained are mapped to the TRIZ engineering parameters, the TRIZ contradiction matrix is constructed according to the TRIZ engineering parameters, and the corresponding innovation principles are obtained. Finally, a specific product innovation design scheme is proposed according to the innovation principles.

The main innovations of this study are as follows:

• Based on the fuzzy Kano model, Kansei engineering, and TRIZ, this study proposes a sustainable innovation design framework currently lacking in the field of smart healthcare products for the elderly. This framework addresses the deficiency in Kansei engineering’s application to product design, which often neglects the innovativeness of design solutions, and it complements the TRIZ field by accounting for users’ emotional needs. This provides methodological guidance for the sustainable innovative design of other product types;
• By innovatively using the systematic classification function of the fuzzy Kano model, this study addresses the irrationality in the screening process of core words of emotional needs in the traditional semantic differential method, thereby enhancing the significance level of core words of emotional needs in improving user satisfaction.

The objectives of this study are as follows:

• To achieve sustainable innovation in the design of elderly-friendly smart medical products, enabling continuous iteration and optimization to meet the complex and changing emotional needs of the elderly;
• To provide a theoretical basis and practical guidance for the government and related industries in formulating policies on CMEC, promoting the innovation of elder-friendly smart medical products, and improving the quality of elderly care services.

In this study, a smart blood pressure monitor was selected as the case study subject. Using Kansei engineering and the fuzzy Kano model, 29 preliminary words of emotional needs were systematically classified. From the nine words of emotional needs categorized under the attractive attribute, three core words of emotional needs were extracted. These three words were then mapped to TRIZ engineering parameters, resulting in corresponding innovation principles. We ultimately selected four highly relevant innovation principles and proposed a sustainable innovation solution for the smart blood pressure monitor based on these principles. The satisfaction survey results showed that 75% of users were either very satisfied or satisfied, confirming the feasibility of the sustainable innovation design framework for elderly-friendly smart medical products.

The remainder of this paper is organized as follows. Section 2 presents a literature review, which introduces the relevant theory and research methods for this study. Section 3 presents the research framework, which involves a sustainable innovation design model for elderly-friendly smart medical products based on the integration of the fuzzy Kano model, Kansei engineering, and TRIZ. Section 4 presents an empirical case study where a smart blood pressure monitor was used as an example, which operated in accordance with the process of the research framework, completing the sustainable innovative design of the smart blood pressure monitor. Section 5 distills the advantages of this study, highlights the policy implications gained, and discusses future research. Section 6 summarizes this study, presenting four key research conclusions.

2. Literature Review

With the increasing extent of population aging, elderly-friendly medical products have become a prominent issue in society. In this study, to address the growing emotional needs of the elderly for elderly-friendly smart medical products, we integrated the fuzzy Kano model, Kansei engineering, and TRIZ to sustainably explore the physiological and psychological emotional needs of the elderly for elderly-friendly smart medical products. We transformed these needs into the corresponding principles of product innovation and design to propose innovative design solutions and complete the sustainable innovative design of elderly-friendly smart medical products. A literature review of related concepts is presented in this section.

2.1. Sustainable Innovative Design of Elderly-Friendly Smart Medical Products

“Elderly-friendly” is a concept derived from the background of the population aging era, originating from the concern for the quality of life of the elderly. It involves considering the needs of the elderly and making corresponding adjustments and designs to buildings, environments, and products to make them suitable for elderly users, to help them adapt to society and enjoy life [32]. Elderly-friendly smart medical products utilize technology to solve problems in the medical and health management of the elderly. They improve the quality of life and health of the elderly while reducing the pressure on the healthcare system, to promote the development of CMEC services toward better intelligence, personalization, and humanization [33]. The sustainable innovative design of elderly-friendly smart medical products aims to meet the emotional needs of the elderly and thoroughly implement the concept of elderly-friendliness.

Sustainable product design is derived from the concept of sustainable development, and it is currently receiving attention from many scholars in the field of product design. van Nes and Cramer [34] discussed how and when product life optimization of consumer goods becomes a challenging strategy for sustainable consumption. Kim and Moon [35] demonstrated how a sustainable product family of electric razors reduced negative environmental impacts through the use of remanufactured modules, while meeting customer needs and maintaining profits. Hossain et al. [36] proposed a sustainable modular product architecture (SMPA) to reduce assembly complexity and middle-aged discarding of products by enhancing the ease of assembly and recovery. He and Mao [37] proposed solving the low-carbon product cascade problem through the integration of digital-twin technology with low-carbon design, resulting in closed-loop sustainable design. According to the aforementioned literature, sustainable product design is mainly focused on cost reduction and efficiency, product quality improvement, and product environmental performance enhancement. Researchers rarely explore methods of product design or optimization from the perspective of sustainable design processes and innovative design solutions—particularly in the field of elderly-friendly smart medical product design.

Technological innovation requires methodological precedence. Innovative product design requires the corresponding method of technology innovation as a precursor [38]. Advanced technological innovation methods can significantly increase the efficiency of product innovation, shorten the cycle of new product development, accelerate product replacement, and improve the market competitiveness of enterprises [39]. The sustainable innovative design of elderly-friendly smart medical products in this study focuses on two main aspects. First, this study emphasizes the sustainability of the design process methods for elderly-friendly smart medical products with thorough consideration of the specific emotional needs of the elderly. Second, this study emphasizes the innovativeness of the design solutions of elderly-friendly smart medical products. The sustainable innovative design of elderly-friendly smart medical products can improve the acceptance of smart medical products by the elderly, promote the sustainable development of the CMEC industry, and make positive contributions to the development of public health.

2.2. Kansei Engineering

Kansei engineering involves designing products, services, and systems by analyzing and understanding human emotions and emotional experiences [40]. It combines the subjective feelings of humans and objective engineering indicators, not only focusing on product functions and technical performance but also taking into account the emotional response and emotional experience of the users through in-depth studies of user preferences, for designing products that are attractive and easy to use [41].

As a sophisticated theory that combines emotions and rationality, Kansei engineering focuses on meeting the emotional needs of users and mapping human emotions to design objects through a rational approach. It plays an important role in smart medical product design, addressing the core issue of emotional connection between humans and machines. Zhu and Yang [42] introduced Kansei engineering into the design of elderly assistive robots to capture the emotional interaction between humans and machines. Hsu and Hsiao [43] optimized the design of a smart pill box by constructing a Kansei health-scape using the Kansei engineering approach. Yuan et al. [16] established a mapping relationship between perceived needs of the users and the design features of medical care beds through Kansei engineering to guide the aesthetic design of the beds and maximize user emotional satisfaction. From the above analysis, we can conclude that the application of Kansei engineering in the design of elderly-friendly medical products is indeed feasible. However, Kansei engineering is primarily used to collect and evaluate user emotional needs. The challenge remains in how to link these processed emotional needs with the innovativeness of the actual product design, achieving sustainable development between “user emotions” and “product innovation”. Current research falls short in addressing this gap.

Common methods used in Kansei engineering include interviews, questionnaires, factor analysis, morphological analysis, structural analysis, and semantic differentials [44,45,46]. Currently, methods such as semantic differential methods, factor analysis, and structural analysis are used, among which semantic differential methods typically utilize semantic differential scales to measure multiple opposing dimensions. This allows the semantic impression of the product to be evaluated on multiple dimensions simultaneously, providing researchers with a more comprehensive understanding of the product characteristics across different dimensions [47]. More importantly, semantic differential scales are usually presented in a graphical format, where participants simply select a location on the graph, making them intuitive and easy to understand. This makes the method applicable to participants of different cultural backgrounds and educational levels [48]. Therefore, in this study, we mainly adopted the semantic differential method, using its scientific validity and simplicity to ensure the sustainability of the design process of elderly-friendly smart healthcare products.

In most studies using the semantic differential method, researchers first collect a large number of preliminary words of emotional needs through various channels. They then design a semantic questionnaire for these words and, based on the questionnaire results, select core words of emotional needs to guide product development. However, during the screening process, a large number of preliminary words of emotional needs are not systematically classified, with all words evaluated along the same dimension. This results in not every core word of emotional needs being at a level that can greatly improve user satisfaction. Some core words of emotional needs may be at a level that makes users feel very satisfied, while others may be at a level that makes users feel satisfied, resulting in serious inconsistency in how core words of emotional needs contribute to user satisfaction. This inconsistency can impact the direction of subsequent product innovation design. Current research has not addressed this issue.

2.3. Fuzzy Kano Model

The Kano model is a methodology developed by Japanese professor Noriaki Kano in 1984 to study the impact of user needs on user satisfaction and thus obtain feedback on the nonlinear relationship between the functional characteristics of a product and user satisfaction, which is used for categorizing and prioritizing improvements of the functional attributes of the product [31]. According to the Kano model, product attributes are categorized into the following five types according to their impact on user satisfaction. ① An attractive attribute (A) refers to an attribute that exceeds user expectations. A small improvement of this attribute would bring substantial satisfaction to the customer. (This attribute can maximize the satisfaction of the emotional needs of the elderly in the present study.) ② A one-dimensional (O) attribute refers to a functional attribute that is expected by users but does not particularly attract their attention. These attributes are basic requirements of a product or service; the lack of these features may lead to dissatisfaction but having them does not significantly increase user satisfaction. ③ A must-be attribute (M) refers to a functional attribute that is taken for granted by the user and is not explicitly mentioned by the user. The lack of this type of attribute causes user dissatisfaction, but the provision of this type of attribute does not impress the user. ④ A reverse attribute (R) refers to a functional attribute that the user does not want, and the provision of this type of functional attribute reduces user satisfaction. ⑤ An indifferent attribute (I) refers to a functional attribute that the user is indifferent to; the presence or absence of this type of functional attribute does not affect user satisfaction [49,50,51]. The relationship between the various functional attributes and user satisfaction is shown in Figure 1.

In the Kano model, the functional-attribute classification tools mainly include the Kano questionnaire, the Kano two-dimensional (2D) matrix evaluation table, and the Kano functional requirement classification table [49]. The Kano questionnaire (

Table 1. Kano questionnaire for functional attributes.

	Options	Like	Expect	Neutral	Accept	Dislike
Question
Functional attribute provided
Functional attribute not provided

) is used to collect customer perceptions and evaluations of different functional attributes. Participants are asked to rate each functional attribute and mark their level of satisfaction. The Kano 2D matrix rating scale (

Table 2. Kano 2D matrix evaluation form.

User Functional Attribute Requirements		Functional Attribute Not Provided
		Like EI	Expect VI	Neutral I	Accept LI	Dislike NI
Functional attribute provided	Like EI	Q	A	A	A	O
	Expect VI	R	I	I	I	M
	Neutral I	R	I	I	I	M
	Accept LI	R	I	I	I	M
	Dislike NI	R	R	R	R	Q

Note: A, Attractive; O, One-dimensional; M, Must-be; R, Reverse; I, Indifferent; Q, Questionable.

) is a tool used to display and analyze the results of the Kano model, typically organized as a 2D matrix. By inputting the results of the Kano questionnaire into this matrix, the specific Kano functional attribute categories can be determined. In this context, A, O, M, R, and I represent the aforementioned categories: attractive attribute, one-dimensional attribute, must-be attribute, reverse attribute, and indifferent attribute, respectively. Q denotes illogical results, which generally do not occur unless the question is poorly formulated, the participant misunderstands the question, or an error occurs during the response process [49]. The Kano functional requirements classification table (

Table 3. Kano functional requirements classification table.

Functional Attribute Number	Functional Attribute Content	Functional Property Frequency									Attribute Category
		A	O	M	I	R	Q	Maximum Value	Maximum Percentage	Sum

) is used to summarize and organize the results of the Kano model analysis, helping teams to develop strategies and priorities for product or service improvement.

The Kano model is used in various fields of research, such as product design and development, service quality assessment, market research and competitive analysis, user experience design, and developing product strategies. Sun et al. [52] proposed the customer–manufacturer–Kano (CM-Kano) model, which categorized customer needs from both the customer’s and manufacturer’s perspectives, providing improvement strategies for product design. Huang et al. [53] used the Kano model to find deficiencies in the quality of urban passenger rail transit services. This was accomplished to comprehensively evaluate the differences between the actual situation of urban rail transit passenger services and the quality of passenger service. Lyu et al. [54] used a combination of the Kano model and quality function deployment (QFD) for technology development and design. The wooden desk of an open office was optimized to improve the rationality and scientific validity of office furniture and enhance its market competitiveness.

In summary, the Kano model effectively categorizes user needs systematically, helping designers identify core requirements that significantly enhance user satisfaction. In this study, with emotional needs being a type of user need, the Kano model addresses the inherent limitations of the semantic differential method in Kansei engineering by systematically classifying preliminary words of emotional needs. Therefore, this study is guided by the Kansei engineering execution process and is the first to integrate the Kano model and the semantic differential method to form an emotional Kano questionnaire, which will be used to categorize different evaluative dimensions of the preliminary words of emotional needs.

Considering that the Kano questionnaire uses five levels—“like”, “expect”, “neutral”, “accept”, and “dislike”—to test the respondents’ sentiments, the uncertainty and ambiguity of the respondents may cause them to misjudge when selecting the options. Fuzzy mathematics provides a way to quantify the respondents’ preference for each option and allows the system to process imprecise or ambiguous information [55,56]. Therefore, fuzzy mathematics is introduced in this study to address the challenge of the inaccuracy of the results of the emotional Kano questionnaire. Finally, the fuzzy Kano model is used to determine the priorities of the emotional needs of the elderly for elderly-friendly smart medical products. Thus, the core emotional needs are obtained, which are used to guide the innovative design of elderly-friendly smart medical products.

2.4. TRIZ

TRIZ is a systematic innovation methodology proposed by Altshuller—a former Soviet scholar—to solve complex problems and discover innovative solutions by analyzing a large number of patent documents and invention cases. TRIZ is based on the principle of universality, which holds that innovation follows certain patterns and that innovation opportunities can be identified by analyzing contradictions and exploiting patterns [57]. Its core concepts include the theory of contradiction, which holds that all problems contain contradictions, and the principle of innovation, which provides a range of ways to resolve contradictions [58]. TRIZ consists primarily of 39 interrelated engineering parameters (Appendix A) and 40 inventive principles (Appendix B). Of these, 39 engineering parameters describe the properties and performance of physical systems, covering everything from structure, geometry, and materials to motion and energy. By analyzing the related engineering parameters in the problem, the nature and limitations of the problem can be clarified, providing direction and inspiration for innovation [59]. The 40 Principles of Invention are basic methods and strategies used in TRIZ to solve problems. They are extracted from thousands of patent documents and cases of invention, representing the patterns of thinking and methods commonly used by humans in the innovation process. These inventive principles cover a wide range of different approaches, including simplification, separation, localized quality change, and reversal, and can help innovators find new ideas and solutions when solving problems [60].

TRIZ was initially applied primarily in the field of engineering to help engineers resolve technical problems and innovate designs [57]. Over time, the field of application for TRIZ has gradually expanded to other areas such as product design. For example, Wang et al. [61] designed and developed a new product called the “very-high-bit-rate digital subscriber line 2” comprising multiple-dwelling units by combining Six Sigma and TRIZ, which made large profits. Uzoka and Mishra [62] provided innovative solutions for product development and design of flow processing equipment by integrating TRIZ with computational fluid dynamics. Vinodh et al. [10] achieved innovative design of automotive components using environmentally conscious quality function deployment (ECQFD), TRIZ, and the analytic hierarchy process (AHP) model as a basis.

In conclusion, TRIZ, with its systematic approach to problem transformation, analysis, and resolution, helps designers break free from conventional thinking and is well-suited for sustainable innovation in elderly-friendly smart medical products. However, the existing literature predominantly focuses on solving technical problems and functional conflicts using TRIZ, with limited attention to aspects like product appearance, user experience, and emotional resonance. The connection between these user-centered needs and TRIZ engineering parameters in developing sustainable innovation solutions remains underexplored.

2.5. Sustainable Innovation Design Framework for Elderly-Friendly Smart Medical Products

From the above analysis, it is clear that the problem of sustainable innovative design of elderly-friendly smart medical products considering the emotional needs of the elderly has yet to be solved, but there is a lack of practical and effective scientific methods to solve such problems. On one hand, Kansei engineering systematically collects information on the emotional needs of the elderly as input information for the design of elderly-friendly smart medical products, and the fuzzy Kano model addresses the limitation of the semantic differential method, where all emotional needs are evaluated on the same dimension, by categorizing different emotional needs systematically to help designers identify the core emotional needs of elderly users. The integration of Kansei engineering and the fuzzy Kano model solves the problems of “what to do” and “sustainability” in the sustainable innovation design process for elderly-friendly smart medical products, but it is insufficient for solving the problem of innovative product design.

On the other hand, TRIZ uses analogies to convert the conflicts or contradictions in the products to be designed into common engineering parameters for finding feasible solutions for product design, which precisely solves the problems of “what to do” and “innovativeness” in the sustainable innovation design process for elderly-friendly smart medical products. However, the market and user needs may not be accurately obtained, which leads to a disconnection between user needs and product design. The integration of Kansei engineering and TRIZ at the intersection of information transfer is advantageous for achieving a sustainable design process and innovative design solutions for elderly-friendly smart medical products and thereby ensuring the flow of information between the designer and the consumer, which provides the perfect complementary advantage. Therefore, we established a sustainable innovation design framework for elderly-friendly smart medical products by integrating the fuzzy Kano model, Kansei engineering, and TRIZ, with further details provided in Section 3.

3. Research Framework

The sustainable innovation design framework for elderly-friendly smart medical products is shown in Figure 2.

3.1. Analysis of Emotional Needs of the Elderly

3.1.1. Elderly-Friendly Smart Medical Product Attribute Category Analysis

The purpose of this step is to identify the product attribute preferences of the users of smart medical products, which will be used a basis for the subsequent categorization of the words of emotional needs and as a point of action for sustainable and innovative product design. First, sample pictures and descriptions of mainstream elderly-friendly smart medical products currently on the market are collected to build a product sample library. Second, an expert panel is formed, where experts can identify intuitive attribute categories of the products, such as appearance, color, and shape, by observing and analyzing the sample pictures of the products. In addition, through the in-depth interpretation of the descriptive information of the product samples, experts can further extract the intrinsic and extrinsic attribute categories of the products, including the functionality, uses, materials, and brand. Finally, the attribute categories of these two parts of the elderly-friendly smart medical products are summarized and organized.

3.1.2. Construction of Vocabulary of Emotional Needs

The collection and organization of the words of emotional needs is a basic step in Kansei engineering. Therefore, we collect as many preliminary words of emotional needs as possible by reviewing the literature related to elderly-friendly smart medical products, such as the thesis literature, magazine advertisements, and the Internet. Then, some of the preliminary words of emotional needs are removed according to the criteria of concreteness, relevance, repetitiveness, and ambiguity. Finally, the remaining words of emotional needs are categorized according to the attribute types of elderly-friendly smart medical products obtained in step 1, to further construct a vocabulary of emotional needs.

3.2. Extraction of Core Emotional Needs of the Elderly

3.2.1. Construction of Key Vocabulary of Emotional Needs

The purpose of this step is to further classify the words in the vocabulary of emotional needs using the emotional Kano questionnaire, paving the way for the construction of the core vocabulary of emotional needs. The emotional Kano questionnaire is based on the original Kano questionnaire with a sentimental element, which categorizes the words in the vocabulary of emotional needs according to the user’s needs. First, each word in the vocabulary of emotional needs is paired with its opposite emotional-needs word using the semantic differential method from Kansei engineering to form word pairs. For example, the emotional-needs word “complex” can be paired with the word “simple” using the semantic differential method, forming the opposing word pair “complex–simple”. This pairing helps to capture an individual’s attitude or emotional response toward a particular object or concept. Second, the word pairs of emotional needs are added to the original Kano questionnaire in Table 1 to obtain the emotional Kano questionnaire, as shown in

Table 4. Emotional Kano questionnaire for a word of emotional needs.

Positive-Emotion Word			Negative-Emotion Word
	Options	Like EI	Expect VI	Neutral I	Accept LI	Dislike NI
Question
Functionality offered by the smart medical product
Functionality not offered by the smart medical product

. Because the evaluation criteria for the emotional Kano questionnaire remain unchanged, the responses of the participants to the positive and negative questions can still be analyzed by using the Kano 2D matrix evaluation table in Table 2. Then, the positive and negative responses in the emotional Kano questionnaire for each word in the vocabulary of emotional needs are compared with the Kano 2D matrix evaluation table to determine the attribute category for each word of emotional need. Subsequently, the Kano functional (emotional) requirements classification table in Table 3 is utilized to complete the frequency count for each attribute category for the words of emotional needs, and the attribute category with the highest frequency is used as the final attribute category for the words of emotional needs. In this study, word pairs of emotional needs belonging to category A (attractive attributes) were selected as key word pairs of emotional needs, and then a key vocabulary of emotional needs was constructed. The results were utilized in the next phase of research on Kansei engineering.

3.2.2. Construction of Core Vocabulary of Emotional Needs

To obtain the core word pairs of emotional needs, it is necessary to perform fuzzification on the emotional Kano questionnaire. The details are as follows.

Step 1: Data fuzzification

Using the triangular fuzzy numbers, the five levels of attitude in the Kano questionnaire are mapped from high to low for each word pair of emotional needs in category A (attractive attribute) as follows: “Like → EI”, “Expected → VI”, “Neutral → I”, “Accept → LI”, and “Dislike → NI”. Additionally, the membership functions of the semantic variables are normalized to the range of {0, 1}, where the semantic variables “EI”, “VI”, “I”, “LI”, and “NI” correspond to the triangular fuzzy numbers (0.75, 1, 1), (0.5, 0.75, 1), (0.25, 0.5, 0.75), (0, 0.25, 0.5), and (0, 0, 0.25), respectively, as shown in Figure 3 [63,64].

Step 2: Calculation of the average triangular fuzzy number

After completing Step 1 of the semantic mapping for each emotional Kano questionnaire data point, each word of emotional needs is associated with a triangular fuzzy number (q, o, p). Suppose a total of k valid emotional Kano questionnaires are collected, and there are m words of emotional needs that need to be evaluated in each questionnaire. In this case, we need to calculate the average triangular fuzzy number for each word of emotional needs.

We define the average triangular fuzzy number for a word of emotional needs as S_tij = (q_tij, o_tij, p_tij), where t denotes the t-th of the k valid emotional Kano questionnaires (1 ≤ t ≤ k, with t being an integer), i represents the i-th word of emotional needs out of the m words (1 ≤ i ≤ m, with i being an integer), and j represents the j-th factor of the triangular fuzzy number corresponding to the i-th word of emotional needs (1 ≤ j ≤ 3, with j being an integer). They are expressed in Equations (1)–(3), respectively.

$$q_{ij}={\displaystyle \frac{1}{k}}{\sum }_{t=1}^k{q}_{tij}$$

(1)

$$o_{ij}={\displaystyle \frac{1}{k}}{\sum }_{t=1}^k{o}_{tij}$$

(2)

$$p_{ij}={\displaystyle \frac{1}{k}}{\sum }_{t=1}^k{p}_{tij}$$

(3)

Since each word pair of emotional needs consists of a positive word of emotional needs and a negative word of emotional needs, we need to calculate the average triangular fuzzy numbers for both the positive and negative words of emotional needs within each pair using Equations (1)–(3). These are denoted as (q_ij+, o_ij+, p_ij+) for the positive words of emotional needs and (q_ij−, o_ij−, p_ij−) for the negative words of emotional needs.

Assuming the weights of the two dimensions are equal [65], we calculate the average value of each factor in the average triangular fuzzy numbers for the positive and negative words of emotional needs within each pair. This results in the composite triangular fuzzy numbers for the word pairs of emotional needs (Q_ij, O_ij, P_ij), as shown in Equations (4)–(6).

$$Q_{ij}=1/2(q_{ij+}+q_{ij-})$$

(4)

$$O_{ij}=1/2(o_{ij+}+o_{ij-})$$

(5)

$$P_{ij}=1/2(p_{ij+}+q_{ij-})$$

(6)

Step 3: Data defuzzification

To clearly express the priority of the word pairs of emotional needs, defuzzification must be performed on the data. In this study, the defuzzification operation is completed using the triangular fuzzy number centering method provided by Shie et al. [63]. Let X denote the defuzzification value of the composite triangular fuzzy numbers of each word pair of emotional needs (Q_ij, O_ij, P_ij); then, the defuzzification operation is performed using Equation (7).

$$X={\displaystyle \frac{Q_{ij}+O_{ij}+O_{ij}+P_{ij}}{4}}$$

(7)

Through the above steps, the core word pairs of emotional needs are obtained (the category A word pairs of emotional needs with the top three defuzzification values are selected) according to the defuzzification value of each category A (attractive attribute) word pair of emotional needs, completing the construction of a core vocabulary of emotional needs.

3.3. Generation of Sustainable Innovative Design Solutions for Elderly-Friendly Smart Medical Products

The purpose of this stage is to determine the innovation and invention principles using the TRIZ engineering parameter table and to propose a sustainable and innovative design solution for elderly-friendly smart medical products based on the innovation and invention principles. First, the core word pairs of emotional needs and the corresponding product attribute categories obtained in the second stage are analyzed, after which they are mapped to the corresponding TRIZ engineering parameters, to transform them into standard TRIZ problems. Second, the TRIZ contradiction matrix is constructed with the obtained TRIZ engineering parameters as a basis, obtaining the corresponding TRIZ innovation and invention principles. Finally, the core word pairs of emotional needs are used to guide product design, and the TRIZ innovation and invention principles are used for product design, which solves the corresponding product design problems and provides sustainable innovation and design solutions for elderly-friendly smart medical products.

4. Empirical Case Studies

With age, human organs gradually decline in function, and the immune system weakens, leading to various chronic diseases for the elderly. Among these, cardiovascular diseases, including hypertension, coronary heart disease, and stroke are leading causes of death among the elderly in China, accounting for up to 44% of the elderly patients with chronic diseases [66]. Thus, smart blood pressure monitors have become elderly-friendly smart medical products with considerable market demand.

CMEC aims to provide comprehensive health support for the elderly by integrating medical resources and elderly services. Under this policy framework, the use of elderly-friendly smart blood pressure devices not only helps the elderly detect and manage cardiovascular diseases in a timely manner but also provides convenient health monitoring services for the elderly as an important part of the home-based care and community-based care models. Therefore, the ubiquitous usage of smart blood pressure devices can help achieve the goals of disease prevention, early intervention, and continuity of care as advocated in the policy of CMEC.

The smart blood pressure monitor is a smart medical device that can meet the daily blood pressure measurement needs of the elderly, and compared with traditional mercury and electronic blood pressure monitors, it has advantages such as convenient data reading, a short pressure measurement time, beeping prompts, and a memory function [67,68,69], satisfying most of the needs of blood pressure measurement in the elderly. However, there are common issues such as poor wearing comfort, lack of design aesthetics, and a user-unfriendly interface, which are attributed to the lack of consideration of the emotional needs of the elderly for smart blood pressure monitors [70]. In this study, considering the wide range of cardiovascular diseases and design problems of the smart blood pressure monitor, the smart blood pressure monitor was selected as the research object, and sustainable innovative design was performed on it, with the goals of enhancing the elderly’s care experience and promoting the development of the policy of integrating medical care and nursing care.

4.1. Analysis of Emotional Needs of the Elderly Regarding Smart Blood Pressure Monitors

4.1.1. Smart Blood Pressure Monitor Product Attribute Category Analysis

Through the major e-commerce platforms, official websites, brochures, and other online and offline channels, we collected and organized a total of 120 sample pictures of mainstream smart blood pressure monitor products and the corresponding sample description information from the market. A smart blood pressure monitor product sample library was constructed, as shown in

Table 5. Smart blood pressure monitor product sample library.

Product Serial Number	Product Catalog Pictures	Sample Description
Sample 1		One-touch activation of blood pressure measurement Movable arm cuff that automatically corrects measurement posture AI voiceover Large storage capacity Plastic and metal finish
Sample 2		Heart rate monitoring LED high-definition large screen Total of 240 sets of dual-user memory Plastic
…	…	…
Sample 118		One-touch activation of blood pressure measurement Automatic pressurization Smart heart rate irregularity detection Plastic and metal finish Large high-definition LED display
Sample 119		Integrated touchscreen and button design AI voiceover WeChat remote notifications Graphical trend analysis One-touch activation of blood pressure measurement Indoor and outdoor temperature difference indication
Sample 120		Revolutionary integrated design Alloy and leather finish Intelligent regulation of pressurization level during pressure measurement Data transfer to cloud Intelligent tips for operation

Note: All pictures and their corresponding descriptions were compiled by the author from various e-commerce platforms, official websites, and brochures.

. Then, three university professors specializing in industrial design and three smart blood pressure monitor product designers were invited to this study as expert panelists. By analyzing pictures of sample smart blood pressure monitors, the six experts concluded that there are two categories of intuitive attributes for the product: appearance design and convenience. By analyzing the descriptive information of smart blood pressure monitor product samples, the experts concluded that there are five categories of intrinsic and extrinsic attributes: functionality, material finish, economy, durability, and technical features. Therefore, design, convenience, functionality, material finish, economy, durability, and technical features were identified as the attribute categories of smart blood pressure monitor products.

4.1.2. Construction of Vocabulary of Emotional Needs for Smart Blood Pressure Monitor Products

Through customers’ comments on e-commerce platforms, magazine advertisements, the relevant literature, and other channels, we collected as many words of emotional needs of the elderly regarding smart blood pressure monitor products as possible. A total of 72 words of emotional needs were collected. Next, the expert panelists analyzed and eliminated the words with repetitive and ambiguous meanings, as well as obvious mismatched words of emotional needs of the elderly. Finally, 29 preliminary words of emotional needs were left, which were classified into the 7 smart blood pressure monitor product attribute categories obtained in the previous step to form a vocabulary of emotional needs, as shown in

Table 6. Vocabulary of emotional needs for smart blood pressure monitor products.

Product Attribute Category	Words of Emotional Needs
Appearance design	Exquisite, colorful, small, stable body, curved or round
Functionality	Human-centered, accurate measurement, with memory function, adjustable font, adjustable volume, adjustable brightness, with operational tips, simple operation, concise data display, fun, touchscreen, soft lighting
Material	Ecofriendly and lightweight
Economy	Cheap
Durability	Durable, long service life, dirt-resistant
Portability	Portable, no assembly required
Technical characteristics	Universal, time-saving start up, sophisticated design, cloud processed

.

4.2. Extraction of Core Emotional Needs of the Elderly Regarding Smart Blood Pressure Monitors

4.2.1. Construction of Key Vocabulary of Emotional Needs for Smart Blood Pressure Monitor Products

The semantic differential method was used to pair the 29 words of emotional needs in the vocabulary of emotional needs in Table 6 with antonyms to form word pairs of emotional needs. Then, the emotional Kano questionnaire was designed for these 29 word pairs of emotional needs, as shown in

Table 7. Emotional KANO questionnaire for smart blood pressure devices (example).

Cloud Processed			Locally Processed
	Options	Like EI	Expect VI	Neutral I	Accept LI	Dislike Ni
Question
The smart blood pressure monitors can provide cloud processed functional services. (Cloud processed)
The smart blood pressure monitors cannot provide cloud processed functional services. (Locally processed)

Note: All pictures were sourced by the author through online collection methods.

. Furthermore, to clarify the emotional needs of the elderly, the completed emotional Kano questionnaire was distributed to the elderly. Questionnaires were distributed to elderly people aged 60 years and above in Quanzhou City, Fujian Province, where the CMEC policy is well implemented and with an aging population. Quanzhou City has four municipal districts: Licheng District, Fengze District, Luojiang District, and Quangang District, in which the proportions of elderly people aged 60 years and above are 24.9%, 32.8%, 14.2%, and 28.1%, respectively. In this study, a stratified sampling method was used to distribute 50, 66, 28, and 56 online and offline questionnaires according to the proportion of the elderly population in the four municipal districts, with a total of 200 distributed questionnaires. A total of 187 questionnaires were collected, and 41 invalid responses were removed according to three screening principles: the respondents did not belong to the age range of ≥60 years, had not purchased and used smart blood pressure monitor products, or had chosen the same answers consecutively and contradictory responses. Finally, 146 valid questionnaires were obtained. We organized the collected valid questionnaire data and determined the category to which the words of emotional needs belonged in each emotional Kano questionnaire according to the 2D Kano matrix rating scale (Table 2), and we summarized the attribute category of each word of emotional needs using the Kano functional (emotional) requirements classification scale (Table 3). The results are presented in

Table 8. Categories of the Kano emotional words.

Serial No.	Content of the Library of Emotions	Functional-Property Frequency
		A	I	M	O	Q	R	Maximum Value	Maximum Percentage	Sum	Attribute Category
1	Accurate measurement–error in displayed value	8	24	24	49	40	1	49	0.33562	146	O
2	Human-centered–mechanical	43	30	11	21	38	3	43	0.29452	146	A
3	Adjustable volume–constant-volume	19	37	11	42	36	1	42	0.28767	146	O
4	Adjustable brightness–constant brightness	23	39	9	40	33	2	40	0.27397	146	O
5	With memory function– without memory function	48	34	7	25	32	0	48	0.32877	146	A
6	Adjustable font–single font display	28	43	3	38	34	0	43	0.29452	146	I
7	With operational tips–without operational tips	18	38	14	42	33	1	42	0.28767	146	O
8	Simple operation–complex operation	16	26	15	52	35	2	52	0.35616	146	O
9	Cloud processed–locally processed	26	48	6	33	32	1	48	0.32877	146	I
10	Universal–specialized	21	41	13	37	31	3	41	0.28082	146	I
11	Time-saving start up– time-consuming	45	34	11	21	33	2	45	0.30822	146	A
12	Soft lighting–cold, hard lighting	23	43	8	39	31	2	43	0.29452	146	I
13	Concise data display–complex data display	49	26	13	20	33	5	49	0.33562	146	A
14	Fun–uninteresting	23	52	4	30	33	4	52	0.35616	146	I
15	Lightweight–heavy	26	34	4	50	31	1	50	0.34247	146	O
16	Small–bulky	54	32	5	19	33	3	54	0.36986	146	A
17	Stable body–unstable body	13	27	18	52	34	2	52	0.35616	146	O
18	Curved (round)–straight (square)	25	51	1	34	32	3	51	0.34932	146	I
19	Touchscreen–keypad	28	46	0	37	32	3	46	0.31507	146	I
20	Exquisite–rough looking	27	38	8	41	31	1	41	0.28082	146	O
21	Portable–fixed	49	27	9	27	33	1	49	0.33562	146	A
22	No assembly required– assembly required	50	28	7	25	33	3	50	0.34247	146	A
23	Colorful–monochromatic	30	46	4	30	32	4	46	0.31507	146	I
24	Sophisticated design–crude design	20	31	14	47	32	2	47	0.32192	146	O
25	Durable–fragile	15	21	15	59	32	4	59	0.40411	146	O
26	Cheap–expensive	52	35	6	24	29	0	52	0.35616	146	A
27	Ecofriendly–contaminated	21	36	6	50	31	2	50	0.34247	146	O
28	Long service life–short service life	21	22	13	55	31	4	55	0.37671	146	O
29	Dirt-resistant–stain-prone	50	32	11	22	29	2	50	0.34247	146	A

.

According to the results in Table 8, a total of nine category A (attractive attribute) word pairs of emotional needs, i.e., key word pairs of emotional needs, were identified in this study.

4.2.2. Construction of Library of Core Emotional Needs for Smart Blood Pressure Monitor Products

To further identify the core emotional needs regarding smart blood pressure monitors for the elderly, the results of the emotional Kano questionnaire were specially processed using triangular fuzzy mathematics, with the aim of ordering the aforementioned nine key word pairs of emotional needs and thereby obtaining the core word pairs of emotional needs. First, the nine key word pairs of emotional needs were converted into the corresponding five levels of the emotional Kano questionnaire results: “Like”, “Expect”, “Neutral”, “Accept”, and “Dislike”. Second, according to the semantic transformation results, Equations (1)–(3) were used to calculate the average triangular fuzzy numbers for both the positive and negative words of emotional needs within each key word pair of emotional needs; then, Equations (4)–(6) were used to calculate the composite triangular fuzzy number (Q_ij, O_ij, P_ij) of each key word pair of emotional needs. Subsequently, using Equation (7), each composite triangular fuzzy number (Q_ij, O_ij, P_ij) was defuzzified, which completed the importance ranking, and the core word pairs of emotional needs were obtained, as shown in

Table 9. Centroid method and the importance ranking for the composite triangular fuzzy numbers (Q_ij, O_ij, P_ij).

Serial No.	Core Word Pairs of Emotional Needs	Qij	Oij	Pij	Defuzzification Value	Importance Ranking
2	Human-centered–mechanical	0.448	0.648	0.779	0.631	6
5	With memory function– without memory function	0.453	0.655	0.784	0.637	4
11	Time-saving start up– time-consuming	0.453	0.653	0.786	0.636	5
13	Concise data display–complex data display	0.463	0.660	0.787	0.642	3
16	Small–bulky	0.462	0.662	0.787	0.643	2
21	Portable–fixed	0.450	0.650	0.774	0.631	6
22	No assembly required– assembly required	0.467	0.667	0.790	0.648	1
26	Cheap–expensive	0.443	0.644	0.778	0.627	7
29	Dirt-resistant–stain-prone	0.443	0.641	0.774	0.625	8

. Finally, the three key word pairs of emotional needs with the highest importance were selected for further study: No. 22 “no assembly required–assembly required”, No. 16 “small–bulky”, and No. 13 “concise data display–complex data display”.

4.3. Generation and Realization of Sustainable Innovative Design Solutions for Smart Blood Pressure Monitor Products

4.3.1. Generation Stage of Sustainable Innovation Design for Smart Blood Pressure Monitor Products

From the results of the preliminary theoretical and questionnaire data analysis, we obtained three core word pairs of emotional needs for smart blood pressure monitors for the elderly. According to the connections between each core word pair of emotional needs and the product attribute category of smart blood pressure monitors, three pairs of technological contradictions were identified: no assembly required–assembly required, small–bulky, and concise data display–complex data display.

The most important word pair of emotional needs is “no assembly required–assembly required”, with “convenience” as the associated product attribute category. Compared with traditional blood pressure monitors that require assembly before use, the elderly want smart blood pressure monitors to have simple steps for operation, which corresponds to No. 33 (Ease of operation) of the 39 engineering parameters in Appendix A. However, an integrated smart blood pressure monitor requires the integration of all the necessary components for blood pressure measurement, which inevitably increases the structural complexity of the smart blood pressure monitor. From the above analysis, it can be concluded that the improvement parameter is No. 33 (Ease of operation), and the deterioration parameter is No. 36 (Device or system complexity).

The second-most important word pair of emotional needs is “small–bulky”, with “appearance design” as its associated product attribute category. Owing to the weakening of physiological functions, the elderly want the smart blood pressure monitor to be as small as possible, so that it is easy to carry around and use at any time. Size reduction in smart blood pressure monitors can be achieved by either reducing the number of functional attributes or by placing multiple functional modules through precision design. However, the former requires the abandonment of certain functional attributes, while the latter requires higher investment costs; these two effects can be consolidated into No. 22 (Loss of energy) of the 39 engineering parameters in Appendix A. From the above analysis, it can be concluded that the improvement parameter is No. 7 (Volume of moving object), and the deterioration parameter is No. 22 (Loss of energy).

The third-most important word pair of emotional needs is “concise data display–complex data display”, with “functionality” as its associated product attribute category. Complex data displays can make it difficult for the elderly to immediately capture blood pressure data. The elderly not only want simple steps to prepare for blood pressure measurements but also for the data retrieval process to be straightforward. A smart blood pressure monitor that displays only blood pressure measurement data, without other complex data displays, would significantly help the elderly conveniently read the data. However, this would also exclude the display of data such as heart rate, body temperature, and room temperature on the smart blood pressure monitor, reducing the applicability of smart blood pressure monitors for other health needs of the elderly. From the above analysis, it can be concluded that the improvement parameter is No. 33 (Ease of operation), and the deterioration parameter is No. 35 (Adaptability or versatility).

In summary, we wish to improve TRIZ engineering parameters No. 7 (Volume of moving object) and 33 (Ease of operation), which would increase the complexity of the product and equipment, incur additional resources and costs, and reduce the versatility of the product. This suggests that TRIZ deterioration parameters No. 36 (Device or system complexity), 22 (Loss of energy), and 35 (Adaptability or versatility) should also be considered. According to improvement parameters No. 7 and 33 and deterioration parameters No. 36, 22, and 35, the contradiction matrix can be constructed as shown in

Table 10. TRIZ contradiction matrix for smart blood pressure devices.

Improvement Parameters	Deterioration Parameters
	22 Loss of Energy	36 Device or System Complexity	35 Adaptability or Versatility
7 Volume of moving object	7/15/13/16
33 Ease of operation		32/26/12/17	15/34/1/16

.

After TRIZ contradiction matrix analysis, experts were asked to filter the products according to the degree of relevancy of the innovation principles to the product attributes of the smart blood pressure monitor. According to the results, innovation principles No. 7, 17, 1, and 15 are strongly correlated, and, correspondingly, four sustainable innovative design solutions (S1, S2, S3, and S4) for smart blood pressure monitors were obtained.

TRIZ innovation principle No. 7 (Nesting) refers to volume reduction by embedding an object into a second object and then embedding both into another object or having the two objects pass through an empty space within another object. This principle inspired the sustainable and innovative design solution S1 for the smart blood pressure monitor: the internal structure of the smart blood pressure monitor is embedded within the cuff and the display is embedded outside the cuff, creating an integrated design. The cuff or arm tube of the smart blood pressure monitor has a large amount of empty space, and a flat design can be adopted, where the internal functional parts of the smart blood pressure monitor are placed inside the cuff, while the display adopts a flexible display screen, which fits snugly with the cuff, allowing easy reading and avoiding interference with blood pressure measurement. The final result is a smart blood pressure monitor that integrates an external flexible display, a central blood pressure measuring cuff, and an internal smart blood pressure monitor chip and other components.

TRIZ innovation principle No. 17 (Transition to a new dimension) refers to the replacement of single-layer structures with multilayer structures or the transformation of functions that are difficult to achieve in one dimension into two dimensions, the transformation of functions that are difficult to achieve in two dimensions into three dimensions, and so on. This principle inspired the sustainable and innovative design solution S2 for the smart blood pressure monitor: “folding design for smart blood pressure monitors”. To address the elderly’s need for a device requiring no assembly and minimal complexity, a folding design can be implemented for the integrated smart blood pressure monitor based on the sustainable innovation design solution S1 (integration). Folding it twice, for example, avoids the need for a design that requires assembly and also reduces the overall size. To avoid damaging internal components during folding, it is necessary to produce a reasonable layout of the internal components of the smart blood pressure monitor during the manufacturing process, where the folded regions are avoided. An external flexible display also satisfies this requirement well.

TRIZ innovation principle No. 1 (Segmentation) refers to the separation and division of a single object into different parts, allowing the separation, assembly, and disassembly of functionalities. This principle inspired the sustainable and innovative design solution S3 for the smart blood pressure monitor: “displaying smart blood pressure meter measurements in a sequential manner”. The elderly need concise data displays, but concise and simple data limit the applicability of smart blood pressure monitors to other health functions. Thus, different types of measurement data can be stored separately, and each type of measurement is individually displayed on the screen in large font. For example, the most important blood pressure data can be displayed first, after which the screen can be swiped to view the next type of measurement. Alternatively, the navigation bar can be used to directly select the measurement that needs to be viewed.

TRIZ innovation principle No. 15 (Dynamicity) refers to the division of an object into parts that move relative to each other or the transformation of immobile parts into dynamic parts. This principle inspired the sustainable and innovative design solution S4 for the smart blood pressure monitor: “cloud upload of smart blood pressure monitor measurements”. On the basis of the S3 sustainable innovation solution, original static data can be uploaded to the cloud for Big Data analysis, real-time dynamic detection of the elderly’s physical health, and timely feedback to the elderly and their families. The results of cloud-based data analysis can simplify the interpretation of blood pressure data for the elderly while facilitating the prevention of emergency situations.

The four sustainable innovative design solutions for smart blood pressure monitor products are summarized in

Table 11. Sustainable innovative design solutions for smart blood pressure monitor products.

Innovation Principle	Service Optimization Solutions
No. 7 (Nesting)	Solution S1: Embed the internal structure of the smart blood pressure monitor inside the cuff and the display outside the cuff to form an integrated design.
No. 17 (Transition to a new dimension)	Solution S2: Folding design for the smart blood pressure monitor.
No. 1 (Segmentation)	Solution S3: Display the measurement data of the smart blood pressure monitor in a sequential manner.
No. 15 (Dynamicity)	Solution S4: Upload smart blood pressure monitor measurement data to the cloud.

.

4.3.2. Realization Stage of Sustainable Innovation Design Solution for Smart Blood Pressure Monitor Products

Using the aforementioned four sustainable innovation design solutions, design sketches were made, as shown in Figure 4.

After completing the design sketches, we conducted prototype design of the smart blood pressure monitor product, and the product rendering was obtained, as shown in Figure 5.

Product design details are shown in Figure 6 (corresponding to solution S1), Figure 7 (corresponding to solution S2), Figure 8 (corresponding to solution S3), and Figure 9 (corresponding to solution S4).

In this study, after the sustainable innovation design for smart blood pressure devices was completed, upstream suppliers and downstream smart blood pressure device retailers were invited to evaluate the applicability of the generated solutions. The following conclusions were drawn. Solution S1 adopts the flattened smart blood pressure monitor design, which allows elderly to carry it around, while the accuracy of various measurements from the smart blood pressure monitor is not reduced. Solution S2 reduces the occupied storage space of the smart blood pressure monitor by >40% through the folding design. Solutions S3 and S4 increase the convenience of data reading, allowing the elderly to obtain data and information 20% faster than before. To survey opinions of the elderly on the smart blood pressure monitor designed in this study regarding convenience and satisfaction, we designed and distributed 100 satisfaction questionnaires (Appendix C) to the elderly. The results suggested that 75% of the elderly were satisfied with the designed smart blood pressure monitor, indicating the feasibility of the proposed methodology.

5. Discussion

5.1. Research Advantages

Considering the policy of integrating medical care and nursing care, along with the trends of population aging and digitalization, it was found that current designs of elderly-friendly smart healthcare products have the issue of inadequate consideration for the emotional needs of the elderly and the lack of innovation in design solutions. Existing research lacks a sustainable innovation design framework to tackle these issues. Therefore, we propose an integrated framework involving the fuzzy Kano model, Kansei engineering, and TRIZ with the aim of achieving sustainable innovative design of elderly-friendly smart medical products oriented to the emotional needs of the elderly. To verify the practicality and effectiveness of this integration framework, the smart blood pressure monitor, which has the largest market share among elderly-friendly smart medical products, was selected for a case study.

The sustainable innovation design framework for elderly-friendly smart medical products is divided into two main parts: comprehensive processing of emotional needs and innovative product design solutions. The comprehensive processing of emotional needs follows the Kansei engineering execution process as the main thread. Initially, 120 product sample pictures and corresponding descriptions of smart blood pressure monitors were collected from various online and offline channels, such as major e-commerce platforms, corporate websites, and brochures. An expert panel categorized the samples into seven attribute categories of smart blood pressure monitors. This step, similar to the studies of Chanyachatchawan et al. [19], Ge et al. [20], and Ren et al. [17], aims to identify the areas of product optimization.

Subsequently, this study gathered 72 emotional need words related to smart blood pressure monitors based on buyer reviews from e-commerce platforms, magazine advertisements, and the relevant literature. After expert screening, 29 preliminary words of emotional needs were selected and matched with the seven attribute categories of smart blood pressure monitors. Finally, instead of the traditional semantic differential questionnaire, an emotional Kano questionnaire was used to classify these 29 words into five categories. Among these, nine words belonged to category A (attractive attribute), which are all at a level that can significantly enhance user satisfaction. Traditional semantic differential questionnaires treat all preliminary words of emotional needs as being on the same evaluative dimension [27,28,71], leading to varied levels of user satisfaction enhancement among the words in the core emotional needs set. The Kano model in this study effectively addresses this issue by classifying all preliminary words of emotional needs before selecting core words from category A (attractive attribute), ensuring the rationality and accuracy of the selection process. Additionally, most existing studies use fuzzy theory to eliminate issues of ambiguity, subjectivity, or uncertainty in participant responses during questionnaire completion [29,30,72]. To address similar issues, this study introduces the fuzzy Kano model, which applies fuzzy theory to improve the objectivity of the emotional Kano questionnaire results. Ultimately, the study identified three core words of emotional needs: “no assembly required”, “small”, and “concise data display”.

In the innovative product design solutions section, the three core words of emotional needs for the smart blood pressure monitor were mapped to TRIZ engineering parameters, resulting in four innovation principles: No. 7 (Nesting), No. 17 (Transition to a new dimension), No. 1 (Segmentation), and No. 15 (Dynamicity). Based on these innovation principles, four innovative design solutions guided by the emotional needs of the elderly were proposed. The overall user satisfaction was 75%, representing an approximate 10% improvement compared to previous studies that focused solely on using Kansei engineering to meet emotional needs while neglecting design innovation [73,74,75]. This indicates that the integration of Kansei engineering and TRIZ in this study is both feasible and effective.

In conclusion, this study provides a pathway for the implementation of sustainable innovative design of elderly-friendly smart medical products through the integration of the fuzzy Kano model, Kansei engineering, and TRIZ. Compared with other product design methods (AHP, QFD, TRIZ, etc.), the integrated model consisting of the fuzzy Kano model, Kansei engineering, and TRIZ provides a sustainable design process and innovative design solution for elderly-friendly smart medical products, addressing the gap in existing research that lacks a sustainable innovation framework. In addition, we used fuzzy methods to eliminate the clear boundaries of the five evaluation levels of the five-point scale, dividing the evaluation level of the user into the evaluation of neighboring levels, and analyzed the degree to which the evaluation level belonged to the evaluation of neighboring levels through the degree of membership of the triangular fuzzy function. This addressed the issues of uncertainties when users filled out the questionnaire, allowing us to obtain more scientific and advanced results.

Table 12. The advantages of this study compared to previous research.

Source	Topic	The Previous Studies
Shi et al. [24], Chanyachatchawan et al. [19], Guo et al. [76], Jiao and Qu [21], Song et al. [45], Wang [18]	User-centered product design	Used Kansei engineering to identify the relationship between products and users’ emotional needs, optimizing product design.
Huang et al. [77], Wang et al. [26], Cao et al. [28], Ding and Bai [27]		Utilized the semantic differential method to filter emotional need words.
Bigorra et al. [78], Lee et al. [79], Xu et al. [31]		Categorized product Kano attributes based on user satisfaction.
Lo et al. [80], Montes et al. [72], Lyu et al. [30]		Processed questionnaire data using a triangular fuzzy function.
Yang et al. [25], Lee et al. [81], Wang [82]	Product innovation design	Integrated QFD and TRIZ for functional innovation in product design.
Vinodh et al. [10], Wang et al. [1], Sousa-Zomer and Cauchick Miguel [83]		Applied AHP to determine the priority of product design quality, then used TRIZ to propose innovative design solutions.
Source	Topic	Strengths of the Present Study
Present study	User-centered sustainable innovation in product design.	Proposed a sustainable innovation design framework for elderly-friendly smart medical products.
		Achieved the connection between elderly users’ emotional needs and innovative product design solutions.
		Designed an emotional Kano questionnaire to address the irrationality in the semantic differential method for filtering emotional need words.
		Used triangular fuzzy numbers to eliminate the ambiguity in respondents’ opinions during questionnaire completion.
		Enhanced user satisfaction with the design of age-friendly smart medical products.

details the specific advantages of this study compared to previous research.

In conclusion, this study provides a pathway for sustainable innovation in the design of age-friendly smart medical products by integrating Kansei engineering, the fuzzy Kano model, and TRIZ. Compared to other product design methods (such as AHP, QFD, TRIZ, etc.), the integrated model in this study offers sustainability in the design process and innovation in design solutions for age-friendly smart medical products, addressing the gap in existing research that lacks a sustainable innovation framework. Additionally, the use of fuzzy logic in this study eliminates the clear boundaries between the five rating levels in the Likert scale, allowing user ratings to be distributed across adjacent levels. This is achieved through the degree of membership in a triangular fuzzy function, which reflects the extent to which a rating belongs to neighboring levels, thereby resolving the uncertainty users may experience when filling out questionnaires. This approach enhances the scientific rigor and sophistication of the research findings. Table 12 details the specific advantages of this study compared to previous research.

5.2. Policy Implications

From the perspectives of relevant enterprises and government, this study yielded the following policy implications.

5.2.1. Implications for Enterprise-Level Research

• Deepen the understanding of user needs and product positioning: before proposing innovative design solutions for the smart blood pressure monitor, this study had already identified that elderly users prefer three key product attributes: “portability”, “appearance design”, and “functionality”. This conclusion was drawn after extensively collecting and analyzing smart blood pressure monitor pictures and descriptions from major e-commerce platforms and academic literature. This comprehensive understanding of user needs and product positioning ensured a smooth connection between demands and the design. Hence, enterprises must deeply understand the specific needs and preferences of elderly users through meticulous market research. This includes understanding their basic needs, expected needs, and attractive needs in the use of medical products. Enterprises should position their products according to these needs to ensure that the design direction matches the actual needs of the users;
• Promote the integration of Kansei engineering and technological innovation: the core idea of the integrated framework combining the fuzzy Kano model, Kansei engineering, and TRIZ is to ensure that the product innovation process is guided by users’ emotional needs. For example, in designing a smart blood pressure monitor, we first identified three core emotional needs: “no assembly required”, “small”, and “concise data display”. These needs were then mapped to propose four innovative design solutions (S1, S2, S3, and S4) for the smart blood pressure monitor, ensuring that the designs meet the emotional needs of the elderly while also maintaining innovation. Thus, when designing elderly-friendly smart medical products, enterprises should integrate the concept of Kansei engineering into the innovation process and should consider the emotional value and innovative design of the products. This implies that the product should not only fulfill the medical needs with regard to functionality but also bring comfort and pleasure to the elderly users in terms of sensory experience;
• Establishment of a management mechanism for continuous innovation and improvement: the integrated framework of the fuzzy Kano model, Kansei engineering, and TRIZ proposed in this study is merely a method to facilitate sustainable innovation in the design of elderly-friendly smart medical products. However, to truly achieve sustainable innovation in product design, fostering innovative thinking within the design team is the key driving force. Therefore, enterprises should establish a management mechanism for continuous innovation and improvement and encourage team members to use TRIZ and other innovation methods to resolve problems in the design and production process. Enterprises need to cultivate the problem awareness and problem-solving skills of the employees and improve the team’s ability to think creatively and solve problems systematically. Meanwhile, the enterprise should establish a mechanism to quickly respond to market changes, collect user feedback in a timely manner, and use it to rapidly improve products for achieving continuous product iteration and optimization.

5.2.2. Implications for Government-Level Research

• Facilitate collaborative innovation among industry, universities, and research institutes: the practical foundation of the sustainable innovation design framework for elderly-friendly smart medical products is not yet particularly solid, and the innovative design solutions for the smart blood pressure monitor remain at the conceptual stage, requiring further practical validation. In fact, advancing the elderly-friendly smart medical products industry requires close collaboration among various departments and entities. In this process, the government should play the role of a bridge to promote cooperation among enterprises, universities, research institutes, and other relevant parties to jointly promote the sustainable and innovative design of elderly-friendly smart medical products. The government can strengthen exchanges and cooperation among various parties by establishing innovation platforms, funding joint R&D projects, and organizing industry exchange meetings. In addition, the government can promote education and training programs for cultivating talent with expertise in elderly-friendly design and smart medical technology to support the long-term development of this industry;
• Encourage the demonstration and promotion of the application of smart medical products in the field of CMEC: in the process of collecting and analyzing the emotional needs of smart blood pressure monitor users, this study found that many elderly users experience anxiety about using smart devices. To address this issue, the government can encourage the demonstration and promotion of the application of elderly-friendly smart medical products in the field of CMEC through the establishment of demonstration zones and demonstration projects. This approach would provide companies with a practical platform to gather user feedback and optimize product performance, thereby significantly reducing the resistance elderly users may feel toward using these products. The government can also raise public awareness of elderly-friendly smart medical products through media publicity and public education to promote social recognition and acceptance of these products;
• Encourage cross-sectoral collaboration to integrate medical and elderly resources: elderly-friendly smart medical products are just one aspect of the broader CMEC services. To accelerate the development of CMEC, the government should play a role in cross-sectoral coordination and integrate resources in the fields of medical care, elderly care, science, and technology. By establishing a cross-sectoral collaboration platform to promote information sharing, resource integration, and collaborative innovation, the government can help enterprises better understand the needs of the elderly while providing them with the necessary support, such as market access, qualifications, and professional guidance.

5.3. Research Limitations and Future Prospects

This study had limitations that need to be addressed in future research. First, we only validated the feasibility of the sustainable innovation design framework for one elderly-friendly smart medical product: the smart blood pressure monitor. This might limit the broader impact and relevance of this study. Second, the method of emotional data collection used in this study is relatively traditional and does not fully ensure the comprehensiveness of the emotional data of the elderly.

In light of these research limitations, future studies can extend the validation and refinement of the proposed sustainable innovation design framework to other elderly-friendly smart medical products, such as smart pill boxes or smart wheelchairs, thereby enhancing the framework’s applicability. Additionally, future research can employ data mining techniques, such as web crawler and text analysis, to improve the emotional data collection process, broadening the scope of data gathered to better meet the emotional needs of the elderly.

6. Conclusions

This study integrates the fuzzy Kano model, Kansei engineering, and TRIZ to propose a sustainable innovation design framework for elderly-friendly smart medical products, using a smart blood pressure monitor as an empirical case study. The main research conclusions are as follows:

• In the design of elderly-friendly smart medical products, the emotional needs of users provide the direction for product innovation, and the innovation of product design solutions is a strong guarantee for meeting these needs. The mutual connection between them is key to achieving sustainable innovation in the design of elderly-friendly smart medical products;
• The integration of Kansei engineering and TRIZ enables the mapping of users’ emotional needs to innovative design solutions for elderly-friendly smart medical products. The fuzzy Kano model effectively addresses the inherent limitations of the semantic differential method, enhancing overall user satisfaction;
• The innovative design of the smart blood pressure monitor based on the sustainable innovation design framework can solve the development problems of upstream suppliers and the sales problems of downstream retailers. More importantly, the designed device was popular among the elderly, confirming that the integrated framework can be used to guide product design and the design scheme development process for smart blood pressure monitors and further verifying the feasibility of the integrated framework for promoting sustainable innovative design of elderly-friendly smart medical products;
• The sustainable innovative design of elderly-friendly smart medical products in this study considers the emotional needs of the elderly, which not only can help the elderly maintain an independent life and enhance their self-management ability through iterative optimization of elderly-friendly smart medical product design and the provision of personalized services, significantly reducing the pressure on community health service centers and alleviating the current situation of the uneven distribution of medical resources, but also promotes the collection and analysis of relevant medical and elderly health data, providing valuable information resources for policymakers and promoting the development of intelligent CMEC.