Temperature stimulation device and method for generating temperature stimulus adjustment model

Abstract

To give a temperature stimulus as intended by a service provider to a user without depending on the setting of the user himself / herself or the answer of the user to a question.SOLUTION: The controller 5 measures the temperature of the skin S using the temperature sensor 4 while controlling the temperature presentation unit 2 to provide a temperature stimulus to the skin S, and acquires, based on the measurement result, a first variation indicating the variation in the temperature of the skin S from the start of the temperature stimulus to a predetermined time and a second variation indicating the variation in the temperature of the skin S from the end of the temperature stimulus to a predetermined time. The acquired first and second amounts of change are input to a temperature stimulus adjustment model representing the relationship between the first and second amounts of change and the reaction time, which is the time required for the user to notice a change in temperature caused by a temperature stimulus, to estimate the reaction time of the user, and the intensity of the temperature stimulus provided by the temperature presentation unit 2 is controlled according to the estimated reaction time of the user.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a thermal stimulation device and a method for generating a thermal stimulation adjustment model. [Background technology]

[0002] BACKGROUND ART Thermal stimulation devices that apply thermal stimulation to human skin are known. Patent Document 1 discloses a hot and cold tactile sensation presentation device, which is an example of this type of thermal stimulation device.

[0003] An article in Non-Patent Document 1 discloses an example of a technology for transmitting taste to people. This technology generates taste sensitivity parameters for each person in advance and uses these parameters to allow other people to experience the taste that one person is experiencing. The taste sensitivity parameters are generated using 25 questions about taste tendencies and their answers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2022 / 158196 [Non-patent literature]

[0005] [Non-Patent Document 1] Mako Uesada, "Can you experience the taste of celebrities?! Experience Docomo's latest technology that lets you share your tastes," [online], January 18, 2024, TECH+, [Retrieved June 20, 2024], Internet<URL:https: / / news.mynavi.jp / techplus / article / 20240118-2865602 / > Summary of the Invention [Problem to be solved by the invention]

[0006] According to the hot and cold tactile sensation presentation device described in Patent Document 1, the intensity of the stimulus given to the user (i.e., the value of the current flowing through the thermoelectric element) is a value preset by the provider of the thermal stimulus service using the hot and cold tactile sensation presentation device. However, because sensitivity to thermal stimuli varies from person to person, this method of setting the intensity may result in the user not feeling a sufficient thermal stimulus, or conversely, feeling it too strongly than necessary, which could result in the thermal stimulus felt by the user deviating from the thermal stimulus intended by the service provider.

[0007] One way to prevent this discrepancy would be to have the user set the stimulation intensity themselves, but this method not only requires the user to take the trouble of adjusting the intensity, but also makes it impossible to set the appropriate intensity, which may not lead to any elimination of the discrepancy.

[0008] It is also possible to parameterize the way a stimulus is felt based on questions posed to the user and their answers, as in Non-Patent Document 1. However, this method also requires the user to take the time and effort to answer questions, and it may not be possible to obtain optimal parameters due to variations in answering criteria among users, and this may not lead to any elimination of the discrepancy.

[0009] Therefore, one of the objects of the present invention is to provide a temperature stimulation device that can provide a user with the temperature stimulation intended by a service provider, regardless of the user's own settings or the user's answers to questions, and a method for generating a temperature stimulation adjustment model to realize such a temperature stimulation device. [Means for solving the problem]

[0010] The temperature stimulation device according to the present invention is a temperature stimulation device connected to a temperature presentation unit that provides a temperature stimulus to a user's skin and a sensor that measures the temperature of the skin. While controlling the temperature presentation unit to provide a temperature stimulus to the skin, the temperature of the skin is measured using the sensor. Based on the results of the measurement, a first temperature change amount indicating the amount of change in the temperature of the skin after the start of the temperature stimulus and a second temperature change amount indicating the amount of change in the temperature of the skin after the end of the temperature stimulus are obtained. The obtained first temperature change amount and second temperature change amount are input into a temperature stimulation adjustment model that indicates the relationship between the first temperature change amount and the second temperature change amount and the reaction time, which is the time it takes for a user to notice a temperature change due to a temperature stimulus, thereby estimating the user's reaction time, and controlling the intensity of the temperature stimulation provided by the temperature presentation unit according to the estimated reaction time of the user.

[0011] The method for generating a thermal stimulus adjustment model according to the present invention is a method for generating a thermal stimulus adjustment model that shows the relationship between a first temperature change amount indicating the amount of change in temperature of a user's skin after a thermal stimulus is applied to the skin, a second temperature change amount indicating the amount of change in temperature of the skin after the thermal stimulus is applied to the skin, and a reaction time, which is the time it takes for the user to notice the temperature change due to the thermal stimulus.The method includes the steps of providing a thermal stimulus to the user's skin, measuring the temperature of the skin, and detecting a user operation indicating that the temperature change has been noticed, acquiring the first temperature change amount and the second temperature change amount based on the results of the measurement, acquiring the reaction time based on the elapsed time from the start of the thermal stimulus to the detection of the user operation, and acquiring the thermal stimulus adjustment model based on the first temperature change amount, the second temperature change amount, and the reaction time acquired for each of a plurality of users. [Effects of the Invention]

[0012] According to the present invention, it is possible to keep the user's reaction time, i.e., the user's perception of thermal stimuli, within a certain range, regardless of the user's own settings or answers to questions. Therefore, it is possible to provide the user with thermal stimuli as intended by the service provider, regardless of the user's own settings or answers to questions. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing the overall configuration of a thermal stimulation system 1 according to an embodiment of the present invention. [Figure 2] 2 is a diagram illustrating an example of a hardware configuration of a controller 5 and a computer 6 illustrated in FIG. [Figure 3] FIG. 10 is a diagram showing the change over time in temperature of the skin S (measured by the temperature sensor 4) when a thermal stimulus (cooling sensation) is provided by the thermal stimulus system 1 in a scene where a thermal stimulus adjustment model is generated. [Figure 4] (a) is a diagram showing a thermal stimulus adjustment model obtained by multiple regression analysis of the results of an experiment in which 24 users were used as subjects and a thermal stimulus was applied to each user's palm and forearm, and (b) and (c) are diagrams showing various data related to the multiple regression analysis of (a). [Figure 5] (a)(b) shows various data related to the multiple regression analysis of Figure 4(a), and (c) shows the relationship between the reaction time RT obtained by the user's sensing operation during the experiment of Figure 4(a) and the estimated value of the reaction time RT obtained by substituting the temperature change amounts δT_start and δT_end obtained by the experiment of Figure 4(a) into the thermal stimulus adjustment model shown in Figure 4(a). [Figure 6] (a) is a diagram showing a thermal stimulus adjustment model obtained by multiple regression analysis of the results of an experiment in which 24 users were used as subjects and a cool thermal stimulus was applied to each user's palm and forearm, and (b) and (c) are diagrams showing various data related to the multiple regression analysis of (a). [Figure 7]6(a) and 6(b) are diagrams showing various data related to the multiple regression analysis of FIG. 6(a), and FIG. 6(c) is a diagram showing the relationship between the reaction time RT obtained by the user's sensing operation during the experiment of FIG. 6(a) and the estimated value of the reaction time RT obtained by substituting the temperature change amounts ΔT_start and ΔT_end obtained by the experiment of FIG. 6(a) into the thermal stimulus adjustment model shown in FIG. 6(a). [Figure 8] FIG. 10 is a flowchart showing a thermal stimulus adjustment model generation process for generating a thermal stimulus adjustment model. [Figure 9] 10 is a flow diagram showing a thermal stimulus provision process for providing a thermal stimulus to the skin S of a user. DETAILED DESCRIPTION OF THE INVENTION

[0014] 1 is a diagram showing the overall configuration of a thermal stimulation system 1 according to an embodiment of the present invention. As shown in the figure, the thermal stimulation system 1 includes a temperature display unit 2, a metal plate 3, a temperature sensor 4, a controller 5, and a computer 6.

[0015] The thermal stimulus system 1 is used both in providing a thermal stimulus to the user's skin S and in generating a thermal stimulus adjustment model required for this purpose. Below, the configuration common to each scenario and the principle of the thermal stimulus adjustment model will be explained with reference to Figures 1 to 7, and then the specific processing performed by the thermal stimulus system 1 in each scenario will be explained with reference to the flow charts shown in Figures 8 and 9.

[0016] The temperature display unit 2 has one or more thermoelectric elements (e.g., Peltier elements) and is a functional unit that realizes a thermal stimulus using the one or more thermoelectric elements. The temperature display unit 2 according to this embodiment is arranged so as to be in close contact with the user's skin S via a metal plate 3, and serves to provide a thermal stimulus to the skin S. While FIG. 1 shows an example in which the skin S is the skin of the user's forearm, it may of course be the skin of another part of the body, such as the palm. The specific method for bringing the temperature display unit 2 into close contact with the user's skin S is not particularly limited. For example, the temperature display unit 2 may be attached to the skin S with adhesive tape, or the temperature display unit 2 may be placed on a table or the like and the user's arm or the like placed on it so that the temperature display unit 2 is brought into close contact with the skin S by the user's own weight, or the temperature display unit 2 may be attached to the lower end of a rod that is fixed so as to be movable only up and down, and the temperature display unit 2 may be brought into close contact with the skin S by lowering the rod with the user's arm or the like placed under the temperature display unit 2.

[0017] The temperature display unit 2 is provided with two current terminals, and one or more thermoelectric elements constituting the temperature display unit 2 are arranged between these current terminals in series or parallel, or in a matrix formed by a combination of series and parallel. The temperature display unit 2 serves to provide either a cooling or warming thermal stimulus depending on the direction of the current flowing between the two current terminals. Furthermore, the strength of the thermal stimulus provided by the temperature display unit 2 increases as the value of the current flowing between the two current terminals increases.

[0018] The metal plate 3 is a metal plate placed between the temperature display unit 2 and the user's skin S. The metal plate 3 is used because it has high thermal conductivity and can quickly bring the temperature display unit 2 and the skin S into thermal equilibrium. In one example, the metal plate 3 may be a copper plate.

[0019] The temperature sensor 4 is a sensor for measuring temperature and is configured, for example, by a thermistor. The temperature sensor 4 is attached to the metal plate 3 and serves to measure the temperature of the metal plate 3. As described above, the metal plate 3 has high thermal conductivity, so the temperature of the metal plate 3 measured by the temperature sensor 4 can be considered to be the temperature of the user's skin S.

[0020] The controller 5 is a device that serves as the thermal stimulus device according to this embodiment and is composed of a small computer connected to the temperature presentation unit 2 and the temperature sensor 4. The controller 5 has the following functions: control the temperature presentation unit 2 to provide a thermal stimulus to the user's skin S; measure the temperature of the skin S using the temperature sensor 4; estimate the user's reaction time (described below) by applying a thermal stimulus adjustment model stored in the computer 6 to the measurement results from the temperature sensor 4; and control the intensity of the thermal stimulus provided by the temperature presentation unit 2 according to the estimation result. Specifically, the control of the temperature presentation unit 2 by the controller 5 is achieved by supplying a positive or negative current to the temperature presentation unit 2. In the following description, the temperature presentation unit 2 provides a cooling thermal stimulus when a positive current is supplied from the controller 5, and provides a warming thermal stimulus when a negative current is supplied from the controller 5.

[0021] The controller 5 also has a function for accepting operations by the user. This function is used to instruct the start of a thermal stimulation, instruct the end of a thermal stimulation, input various parameters (see steps S20 and S21 in FIG. 7) described below, input that a temperature change has been detected, etc. Hereinafter, the operation for instructing the start of a thermal stimulation will be referred to as the "start operation," and the operation for inputting that a temperature change has been detected will be referred to as the "sensing operation."

[0022] The computer 6 is a computer that stores the thermal stimulus adjustment model and is configured, for example, as a personal computer or a server computer. An API (Application Programming Interface) that enables the controller 5 to use the thermal stimulus adjustment model is implemented in the computer 6, and the controller 5 is configured to acquire the thermal stimulus adjustment model from the controller 5 via this API. Note that while the controller 5 and the computer 6 are depicted as separate devices in FIG. 1, the controller 5 and the computer 6 may also be implemented as a single computer. Furthermore, the controller 5 and the computer 6 may be connected by wire or wirelessly, or may be connected via the Internet. Specific details of the thermal stimulus adjustment model will be described later.

[0023] 2 is a diagram showing an example of the hardware configuration of the controller 5 and the computer 6. The controller 5 and the computer 6 can each be configured as a computer 100 having the configuration shown in the figure. Note that the computer 100 that constitutes the computer 6 may be a computer configured by combining multiple computers.

[0024] As shown in FIG. 2, the computer 100 has a configuration in which a CPU (Central Processing Unit) 101, a storage device 102, an input device 103, an output device 104, and a communication device 105 are interconnected via a bus 106.

[0025] The CPU 101 is a device that controls each part of the computer 100 and also reads and executes various programs stored in the storage device 102. The storage device 102 includes a main storage device such as a dynamic random access memory (DRAM) and an auxiliary storage device such as a hard disk, and serves to store various programs for executing the operating system and various applications of the computer 100, as well as data used by these programs. The processes shown in Figures 8 and 9, which will be described later, are realized by the CPUs 101 of the controller 5 and the computer 6 executing programs stored in their respective storage devices 102.

[0026] The input device 103 is a device that accepts external input and supplies it to the CPU 101, and is configured to include, for example, a keyboard, a mouse, and a touch panel. Operations performed by the user on the controller 5 are accepted by the input device 103 of the controller 5 and supplied to the CPU 101 of the controller 5. The input device 103 of the controller 5 may include hardware buttons for accepting the above-mentioned start operation and sensing operation. Furthermore, the input device 103 of the controller 5 includes an interface for connecting to the temperature sensor 4, and the CPU 101 of the controller 5 is configured to acquire the measurement results of the temperature sensor 4 via this interface.

[0027] The output device 104 is a device that outputs the processing results of the CPU 101 to the outside, and is configured to include, for example, a display and a speaker. The output device 104 of the controller 5 includes an interface for connecting to the temperature display unit 2, and the CPU 101 of the controller 5 is configured to control the temperature display unit 2 by supplying current to the temperature display unit 2 via this interface.

[0028] The communication device 105 is a device for communicating with external devices, and transmits and receives data according to instructions from the CPU 101. The controller 5 and the computer 6 are each configured to use this communication device 105 to communicate with other devices, including each other.

[0029] Figure 3 shows the time course of the temperature of the skin S (measured by the temperature sensor 4) when a thermal stimulus (cooling sensation) is provided by the thermal stimulus system 1 in the process of generating a thermal stimulus adjustment model. In the initial state of the figure, the temperature display unit 2 and the skin S are maintained in thermal equilibrium, and the temperature of the skin S measured by the temperature sensor 4 is 32°C, the temperature of a typical forearm.

[0030] When the controller 5 starts supplying a positive current to the temperature display unit 2 in response to a start operation by the user, the temperature display unit 2 starts a cooling thermal stimulus, and the temperature of the skin S decreases. The illustrated temperature change amount ΔT_start is the amount of change in temperature of the skin S after the start of the thermal stimulus (first temperature change amount). In one example, as illustrated in FIG. 3, the temperature change amount ΔT_start may be the amount of change in temperature over a predetermined time period (one second in the example of FIG. 3) from the start of the thermal stimulus. However, considering that the period from the start to the end of the thermal stimulus (=sensing operation) may be less than one second, the temperature change amount ΔT_start may be the amount of change per unit time (one second) obtained by dividing the amount of change in temperature of the skin S over the period from the start to the end of the thermal stimulus by the length of the period. Because the temperature change from the start to the end of the thermal stimulus is roughly proportional to the time, the temperature change amount ΔT_start will be approximately the same regardless of the calculation method.

[0031] Thereafter, when the user performs a sensing operation, the controller 5 stops the supply of current to the temperature display unit 2. The illustrated reaction time RT is the time from the start of the thermal stimulus to the user performing the sensing operation. When the supply of current stops, the temperature display unit 2 ends the thermal stimulus, and as a result, the temperature of the skin S begins to rise. The illustrated temperature change amount ΔT_end is the amount of change in temperature of the skin S after the end of the thermal stimulus (second temperature change amount). In one example, as illustrated in FIG. 3, the amount of change in temperature over a predetermined time period (1 second in the example of FIG. 3) from the end of the thermal stimulus may be set to the temperature change amount ΔT_end.

[0032] One of the features of the present invention is the discovery of a multiple correlation between the temperature change amounts δT_start, δT_end and reaction time RT. In other words, by performing multiple regression analysis on the measurement results of the temperature change amounts δT_start, δT_end and reaction time RT, it is possible to create a regression equation (= thermal stimulus adjustment model) with the temperature change amounts δT_start, δT_end as explanatory variables and reaction time RT as the target variable. Therefore, if the temperature change amounts δT_start, δT_end are measured while a thermal stimulus is being applied to the user, reaction time RT can be obtained by substituting the measurement results of the temperature change amounts δT_start, δT_end into this regression equation, even without any sensing operation by the user.

[0033] Here, a roughly proportional relationship exists between the reaction time RT and the user's sensitivity. In other words, the longer the reaction time RT, the less sensitive the user is to the thermal stimulus, and conversely, the shorter the reaction time RT, the more sensitive the user is to the thermal stimulus. Therefore, if the reaction time RT can be obtained during the thermal stimulus, the service provider can adjust the intensity of the thermal stimulus based on that reaction time RT, thereby enabling the service provider to provide the user with the thermal stimulus as intended.

[0034] Therefore, in the thermal stimulus system 1 according to this embodiment, a thermal stimulus is first provided to a certain number of users, and a thermal stimulus adjustment model is derived based on the temperature change amounts ΔT_start, ΔT_end, and reaction time RT obtained during the provision. Then, when providing a thermal stimulus to each user, the temperature change amounts ΔT_start, ΔT_end are measured, and the results are substituted into the thermal stimulus adjustment model to determine the user's reaction time RT. The intensity of the subsequent thermal stimulus is then adjusted based on the obtained reaction time RT, allowing the service provider to provide the user with the thermal stimulus as intended.

[0035] Figure 4(a) shows a thermal stimulus adjustment model obtained by multiple regression analysis of the results of an experiment in which 24 users were subjects and a warm thermal stimulus was applied to each user's palm and forearm. Figures 4(b)(c) and 5(a)(b) show various data related to the multiple regression analysis of Figure 4(a). Figure 5(c) shows the relationship between the reaction time RT obtained by the user's sensing operation in the experiment of Figure 4(a) and the estimated reaction time RT obtained by substituting the temperature changes δT_start and δT_end obtained from the experiment of Figure 4(a) into the thermal stimulus adjustment model shown in Figure 4(a). Similarly, Figure 6(a) shows a thermal stimulus adjustment model obtained by multiple regression analysis of the results of an experiment in which 24 users were subjects and a cool thermal stimulus was applied to each user's palm and forearm. 6(b)(c) and 7(a)(b) are diagrams showing various data related to the multiple regression analysis of FIG. 6(a), and FIG. 7(c) is a diagram showing the relationship between the reaction time RT obtained by the user's sensing operation during the experiment of FIG. 6(a) and the estimated value of the reaction time RT obtained by substituting the temperature change amounts ΔT_start and ΔT_end obtained by the experiment of FIG. 6(a) into the thermal stimulus adjustment model shown in FIG. 6(a).

[0036] First, referring to Figure 4(a), in the case of thermal sensation, assuming a linear model with temperature changes δT_start and δT_end as primary variables and using the least squares method to find the coefficients and intercepts, we obtain a thermal stimulus adjustment model of RT = -1.55δT_start - 1.15δT_end + 1.19, as shown in the figure. The correlation coefficients -1.55, -1.15, and +1.19 appearing in this thermal stimulus adjustment model have p-values ​​significantly smaller than 0.05, indicating that these values ​​are significant. Furthermore, when the correlation coefficient between temperature changes δT_start and δT_end was calculated, a value of -0.22 was obtained. However, because the p-value for this value is greater than 0.05, it is believed that there is no significant correlation between temperature changes δT_start and δT_end.

[0037] The multiple correlation coefficient R and corrected coefficient of determination R of the obtained thermal stimulus adjustment model 2 The calculated values ​​were 0.76 and 0.56, respectively. Therefore, according to the obtained thermal stimulus adjustment model, it can be said that the two explanatory variables are able to sufficiently explain the objective variable. The adjusted coefficient of determination R 2 The p-value was also less than 0.05.

[0038] Next, referring to Figure 5(c), it can be seen that the reaction time RT can be accurately estimated from the measurement results of the temperature changes ΔT_start and ΔT_end using the thermal stimulus adjustment model shown in Figure 4(a), at least within the range of reaction time RT of 5 seconds or less. Therefore, it can be said that, within a practical range, by estimating the reaction time RT using the thermal stimulus adjustment model shown in Figure 4(a), in the case of a warm sensation, it is possible for the service provider to provide the user with the thermal stimulus intended.

[0039] Next, referring to Figure 6(a), in the case of cold sensation, we similarly assumed a linear model with the temperature changes δT_start and δT_end as primary variables. Using the least squares method to calculate the coefficients and intercepts, we obtained the thermal stimulus adjustment model RT = 0.32δT_start + 0.38δT_end + 2.26, as shown in the figure. The correlation coefficients +0.32, +0.38, and +2.26 in this thermal stimulus adjustment model all have p-values ​​significantly smaller than 0.05, indicating that these values ​​are significant. Furthermore, the correlation coefficient between the temperature changes δT_start and δT_end was found to be -0.37, but the p-value for this value was greater than 0.05, suggesting that there is again no significant correlation between the temperature changes δT_start and δT_end.

[0040] The multiple correlation coefficient R and corrected coefficient of determination R of the obtained thermal stimulus adjustment model 2 The calculated values ​​were 0.87 and 0.74, respectively. Therefore, in the case of cold sensation, the obtained thermal stimulus adjustment model can be said to be able to sufficiently explain the two explanatory variables. In this case, too, the corrected coefficient of determination R 2 The p-value was less than 0.05.

[0041] Next, referring to Fig. 7(c), it can be seen that the reaction time RT can be accurately estimated from the measurement results of the temperature changes ΔT_start and ΔT_end using the thermal stimulus adjustment model shown in Fig. 6(a). Therefore, by estimating the reaction time RT using the thermal stimulus adjustment model shown in Fig. 6(a), it can be said that even in the case of a cold sensation, it is possible for the service provider to provide the user with the thermal stimulus as intended.

[0042] Next, the processing performed by the controller 5 will be specifically described with reference to Figures 8 and 9, with respect to a scene in which a thermal stimulus is provided to the user's skin S and a scene in which a thermal stimulus adjustment model required for that purpose is generated.

[0043] 8 is a flow diagram showing the thermal stimulus adjustment model generation process for generating a thermal stimulus adjustment model. This process is basically executed by the controller 5, but the processes indicated by dashed lines in the figure are executed manually.

[0044] As shown in Fig. 8, in this process, the controller 5 first sets the value of the current supplied to the temperature display unit 2 to an initial value (step S1). The initial value set here is a positive value when deriving a thermal stimulus adjustment model for a cold sensation, and a negative value when deriving a thermal stimulus adjustment model for a warm sensation. While performing the thermal stimulus adjustment model generation process, the controller 5 maintains the value of the current supplied to the temperature display unit 2 at the initial value set here.

[0045] Next, when the user puts on the temperature display unit 2 (step S2), the controller 5 waits for a start operation by the user (step S3). After that, upon detecting the start operation, the controller 5 waits further until the temperature measured by the temperature sensor 4 reaches a constant value (step S4), and then starts supplying current to the temperature display unit 2 (step S5). This starts a thermal stimulus from the temperature display unit 2 to the skin S.

[0046] The controller 5, which started the thermal stimulation in step S5, records the amount of temperature change ΔT_start after the start of the thermal stimulation in association with the user (step S6). The controller 5 waits for a sensing operation by the user (step S7). After that, upon detecting the sensing operation, the controller 5 stops the supply of current to the temperature display unit 2 (step S8), thereby ending the thermal stimulation, and records the reaction time RT, which is the time from the start of the thermal stimulation to the detection of the sensing operation, in association with the user (step S9). The controller 5 also records the amount of temperature change ΔT_end after the end of the thermal stimulation in association with the user (step S10).

[0047] Next, it is determined whether the expected number of samples (e.g., 48 samples) have been collected (step S11). If not, the user or measurement site is changed as necessary, and the process from step S2 is repeated. On the other hand, if it is determined that the expected number of samples have been collected, a regression equation representing the reaction time RT is derived using the temperature changes ΔT_start and ΔT_end by performing multiple regression analysis based on the recorded results up to that point (step S12). Specific examples of the regression equation derived in this way are shown in Figures 4(a) and 6(a). The process up to this point completes the generation of the thermal stimulus adjustment model, and the generated thermal stimulus adjustment model is written into computer 6.

[0048] 9 is a flow diagram showing a thermal stimulus provision process for providing a thermal stimulus to the user's skin S. This process is also basically executed by the controller 5, but the processes indicated by dashed lines in the figure are processes performed by a person.

[0049] First, based on the intention of the service provider, the upper limit value THU (first predetermined value) and lower limit value THL (second predetermined value smaller than the first predetermined value) of the reaction time RT, as well as parameters for the duration of the thermal stimulus, are set in the controller 5 (steps S20 and S21). The range of the reaction time RT set in step S20 represents the range of sensations intended by the service provider.

[0050] The controller 5 also sets the value of the current to be supplied to the temperature display unit 2 to an initial value (step S22). As in step S1 of Fig. 6, the initial value set here is a positive value when deriving a thermal stimulus adjustment model for a cold sensation, and a negative value when deriving a thermal stimulus adjustment model for a warm sensation.

[0051] Next, when the user puts on the temperature display unit 2 (step S23), the controller 5 waits for a start operation by the user (step S24). After that, upon detecting the start operation, the controller 5 waits further until the temperature measured by the temperature sensor 4 reaches a constant value (step S25), and then starts supplying current to the temperature display unit 2 (step S26). This starts a thermal stimulus from the temperature display unit 2 to the skin S.

[0052] The controller 5, which started the thermal stimulation in step S26, records the temperature change amount ΔT_start after the start of the thermal stimulation (step S27), while waiting for the arrival of the timing to end the thermal stimulation indicated by the duration of the thermal stimulation set in step S21 (step S28). After that, when the controller 5 detects the arrival of the timing to end the thermal stimulation, it stops the current supply to the temperature display unit 2 (step S29), thereby ending the thermal stimulation, and records the temperature change amount ΔT_end after the end of the thermal stimulation (step S30).

[0053] Next, the controller 5 calculates an estimated value EV of the reaction time RT (step S31) by substituting the temperature change amount ΔT_start recorded in step S27 and the temperature change amount ΔT_end recorded in step S30 into the regression equation derived in step S12 of Fig. 8. Then, the controller 5 compares the calculated estimated value EV with the upper limit value THU and lower limit value THL of the reaction time RT set in step S20 (steps S32, S34).

[0054] If the comparison shows that the estimated value EV is longer than the upper limit value THU (i.e., the user's sensation is weaker than intended by the service provider), the controller 5 increases the value of the current passed through the temperature display unit 2 (step S33), thereby controlling the temperature display unit 2 so as to intensify the thermal stimulus provided to the user's skin S, and the process returns to step S24. In step S33, the controller 5 may determine the amount of increase in the value of the current passed through the temperature display unit 2 according to the amount of difference (difference or ratio) between the estimated value EV and the upper limit value THU.

[0055] On the other hand, if the estimated value EV is shorter than the lower limit value THL (i.e., if the user's sensation is stronger than intended by the service provider), the controller 5 controls the temperature display unit 2 to weaken the thermal stimulus provided to the user's skin S by reducing the value of the current passed through the temperature display unit 2 (step S35), and then returns to step S24. In step S35, the controller 5 may determine the amount of reduction in the value of the current passed through the temperature display unit 2 according to the amount of difference (difference or ratio) between the estimated value EV and the lower limit value THL.

[0056] If the estimated value EV is between the lower limit value THL and the upper limit value THU, the controller 5 returns to step S24 without changing the value of the current flowing through the temperature display unit 2. By performing the processing up to this point, it becomes possible to make the user feel the thermal stimulus in a way that is closer to the service provider's intention from the next thermal stimulus onwards.

[0057] As described above, the thermal stimulation system 1 according to this embodiment makes it possible to keep the user's reaction time RT, i.e., the user's perception of the thermal stimulation, within a certain range (between the lower limit THL and the upper limit THU), regardless of the user's own settings or the user's responses to questions. Therefore, it can be said that the service provider can provide the user with the thermal stimulation intended, regardless of the user's own settings or the user's responses to questions.

[0058] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it goes without saying that the present invention can be embodied in various forms without departing from the spirit of the present invention.

[0059] For example, in the above embodiment, the temperature change amount ΔT_start was the temperature change amount from the start of the thermal stimulus until one second later, but it may be any temperature change amount from the start of the thermal stimulus until a certain time has elapsed. Similarly, the temperature change amount ΔT_end was the temperature change amount from the end of the thermal stimulus until one second later, but it may be any temperature change amount from the end of the thermal stimulus until a certain time has elapsed. This certain time may be the same for the temperature change amount ΔT_start and the temperature change amount ΔT_end, or it may be different. [Explanation of symbols]

[0060] 1. Thermal stimulation system 2 Temperature display section 3 metal plate 4 Temperature Sensors 5 Controller 6. Computer 100 computers 101 CPU 102 Storage device 103 Input Device 104 Output Device 105 Communication equipment Bus 106 S skin

Claims

1. A temperature stimulus device connected to a temperature presentation unit that provides a temperature stimulus to the skin of a user and a sensor that measures the temperature of the skin, measuring the temperature of the skin using the sensor while controlling the temperature presentation unit to provide a temperature stimulus to the skin; Based on the results of the measurement, a first temperature change amount indicating a change amount of the skin temperature after the start of the thermal stimulation and a second temperature change amount indicating a change amount of the skin temperature after the end of the thermal stimulation are obtained; The reaction time of the user is estimated by inputting the acquired first temperature change amount and the second temperature change amount into a thermal stimulus adjustment model that indicates a relationship between the first temperature change amount and the second temperature change amount and a reaction time, which is a time until the user notices a temperature change due to a thermal stimulus; controlling the intensity of the thermal stimulus provided by the temperature presentation unit in accordance with the estimated reaction time of the user; Temperature stimulator.

2. If the estimated reaction time of the user is longer than a first predetermined value, the temperature display unit is controlled so that the thermal stimulus provided to the skin of the user becomes stronger; If the estimated reaction time of the user is shorter than a second predetermined value that is smaller than the first predetermined value, the temperature display unit is controlled so that the thermal stimulus provided to the skin of the user is weakened. The thermal stimulation device according to claim 1 .

3. The thermal stimulus adjustment model is represented by a regression equation showing that a two-dimensional linear function having variables of the first temperature change amount and the second temperature change amount is equal to the reaction time. The thermal stimulation device according to claim 1 or 2.

4. The thermal stimulus is a cooling stimulus that lowers the temperature of the skin. The thermal stimulation device according to claim 1 or 2.

5. The thermal stimulus is a warming stimulus that increases the temperature of the skin. The thermal stimulation device according to claim 1 or 2.

6. A method for generating a thermal stimulus adjustment model showing a relationship between a first temperature change amount indicating a change amount of temperature of a user's skin after a thermal stimulus is started on the skin, a second temperature change amount indicating a change amount of temperature of the skin after a thermal stimulus is ended on the skin, and a reaction time which is a time until the user notices a temperature change due to the thermal stimulus, providing a thermal stimulus to a user's skin while measuring the temperature of the skin and detecting a user operation indicating that the user has noticed a temperature change; acquiring the first temperature change amount and the second temperature change amount based on the measurement results; acquiring the reaction time based on an elapsed time from the start of the thermal stimulus to the detection of the user operation; acquiring the thermal stimulus adjustment model based on the first temperature change amount, the second temperature change amount, and the reaction time acquired for each of a plurality of users; A method comprising:

7. The thermal stimulus adjustment model is represented by a regression equation showing that a two-dimensional linear function having variables of the first temperature change amount and the second temperature change amount is equal to the reaction time. The method of claim 6.

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