Cold Sensation Display Device and Program

Abstract

This cold sensation presentation device comprises: a cold stimulation unit that applies a cold stimulus to a skin in a noncontact manner; a warm stimulation unit that applies a warm stimulus to the skin in a noncontact manner; and a control unit that presents a cold sensation by making different from each other a change over time in intensity of the cold stimulus in a cold stimulation state in which the intensity of the warm stimulus is relatively low and a change over time in intensity of the warm stimulus in a warm stimulation state in which the intensity of the warm stimulus is relatively high and by repeating the cold stimulation state and the warm stimulation state in a state in which the intensity of the cold stimulus is maintained constant.

Description

Technical Field

[0001] The present invention relates to a cold sensation presentation device and a program.

Background Art

[0002] Conventionally, a device for applying a temperature stimulus to the skin of a subject has been proposed (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Such a device for applying a temperature stimulus preferably gives the subject a natural feeling of being in a real environment while artificially reproducing the real environment. However, according to the above-described technology, since a temperature stimulus is applied by contacting the skin of the subject, there are cases where a natural feeling cannot be given.

[0005] The present invention has been made in view of the above points, and provides a cold sensation presentation device and a program capable of continuously giving a cold sensation close to a real environment.

Means for Solving the Problems

[0006] One aspect of the present invention is a cold sensation presenting device including: a cold stimulation unit that applies a cold stimulation to the skin without contacting the skin; a warm stimulation unit that applies a warm stimulation to the skin without contacting the skin; a control unit that presents a cold sensation by repeating the cold stimulation state, in which the intensity of the warm stimulation is relatively low, and the warm stimulation state, in which the intensity of the warm stimulation is relatively high, while making the time change of the intensity of the cold stimulation different from the time change of the intensity of the warm stimulation and keeping the intensity of the cold stimulation constant.

[0007] One aspect of the present invention is that, in the above cold sensation presenting device, the control unit keeps the intensity of the cold stimulation constant by keeping the temperature and flow rate of the cold air constant.

[0008] One aspect of the present invention is that, in the above cold sensation presenting device, the control unit changes the intensity of the warm stimulation over time from a relatively low state to a relatively high state in the warm stimulation state.

[0009] One aspect of the present invention is that, in the above cold sensation presenting device, the control unit ends the cold sensation presentation by decreasing the intensity of the cold stimulation and the intensity of the warm stimulation, or by decreasing the presentation time of the cold stimulation and the presentation time of the warm stimulation.

[0010] One aspect of the present invention is that, in the above cold sensation presenting device, among conduction, convection, and radiation, which are types of heat transfer methods, the type by which the cold stimulation unit applies the cold stimulation is different from the type by which the warm stimulation unit applies the warm stimulation.

[0011] A program for causing a computer that controls a cold sensation presenting device including a cold stimulation unit that applies a cold stimulation to the skin without contacting the skin and a warm stimulation unit that applies a warm stimulation to the skin without contacting the skin to execute: making the time change of the intensity of the cold stimulation in a cold stimulation state, in which the intensity of the warm stimulation is relatively low, different from the time change of the intensity of the warm stimulation in a warm stimulation state, in which the intensity of the warm stimulation is relatively high, and repeating the cold stimulation state and the warm stimulation state while keeping the intensity of the cold stimulation constant.

Advantages of the Invention

[0012] According to the present invention, it is possible to continuously provide a cold sensation close to the actual environment.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

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Figure 10

Figure 11

Figure 12

Modes for Carrying Out the Invention

[0014] [Background Art] Thermal sensation, a type of cutaneous sensation, not only plays a role in recognizing the material and state of the touched object, but also has the role of recognizing the cold and heat of the environment in which one is located. Therefore, it is possible to artificially reproduce and expand real objects and environments with a thermal sensation display. Conventionally, research has been actively conducted on transmitting the thermal characteristics of an object using a contact-type display using a Peltier element. However, if non-contact thermal sensation control is realized, it will be possible to present the sensation of going to environments such as Antarctica or the tropical rainforest. Furthermore, if thermal sensation can be continuously presented, it will also be possible to have the sensation of being in the environment, which is expected to lead to the realization of new sensation and emotion control. In order to reproduce the thermal sensation in a state of immersion in the environment, continuous presentation of thermal sensation is required, rather than immediate (short-time) presentation. Many conventional technologies are limited to immediate presentation of thermal sensation. For example, immediate contact thermal sensation presentation using cold water and warm water, and immediate non-contact warm sensation presentation using an LED (light-emitting diode) are being carried out. Also, an immediate non-contact cold sensation control method using an ultra-low temperature cold air flow has been realized. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0015] [Embodiment] FIG. 1 is a diagram showing an example of the configuration of a cold sensation presentation device 1 according to the present embodiment. In the following, when necessary, a three-dimensional orthogonal coordinate system of the x-axis, y-axis, and z-axis will be used for explanation.

[0016] The cold sensation presentation device 1 includes a cold stimulation unit 10, a warm stimulation unit 20, and a control unit 30. The control unit 30 includes, for example, a computer that operates according to a predetermined program, and controls each part of the cold sensation presentation device 1.

[0017] The cold stimulation unit 10 includes a cold air generation unit 11, a flow rate control unit 12, and a presentation unit 13. The cold air generation unit 11 generates cold air at a predetermined flow rate. The flow rate control unit 12 controls the flow rate of the cold air generated by the cold air generation unit 11. The flow control unit 12 controls the flow rate of the cold air generated by the cold air generation unit 11. As an example, the flow control unit 12 includes a solenoid valve. The flow control unit 12 controls the flow rate of the cold air 14 by changing the opening degree of the solenoid valve to an opening degree corresponding to the PWM (pulse width modulation) current applied from the control unit. The presentation unit 13 discharges the cold air 14 whose flow rate is controlled by the flow control unit 12 in the z-axis direction.

[0018] The thermal stimulation unit 20 includes a light source 21. The light source 21 emits light 22 with an intensity corresponding to the control of the control unit 30. Note that the thermal stimulation unit 20 may include a plurality of light sources 21. Hereinafter, the configurations of each unit will be described more specifically.

[0019] FIG. 2 is a diagram showing an example of the configuration of the cold air generation unit 11 of the present embodiment. As an example, the cold air generation unit 11 includes a vortex tube 16. The vortex tube 16 swirls the compressed air 15 supplied from an air compressor (not shown) and separates it into warm air and cold air. The cold air generation unit 11 guides the cold air among the warm air and cold air separated in the vortex tube 16 to the presentation unit 13 via the flow control unit 12 (not shown in the figure).

[0020] FIG. 3 is a diagram showing an example of the configuration of the presentation unit 13 of the present embodiment. The presentation unit 13 includes a cold air discharge port 131 at a substantially central position in the xy plane. The cold air discharge port 131 discharges the cold air 14 in the z-axis direction. The cold air 14 is discharged, for example, toward the skin 2 and takes heat H1 from the skin 2. That is, the cold stimulation unit 10 gives a cold stimulation to the skin 2 without contact. Note that the presentation unit 13 may include a wall portion 132 having a height in the z-axis direction around the cold air discharge port 131. This wall portion 132 suppresses the cold air 14 discharged from the cold air discharge port 131 from diffusing in the xy plane direction.

[0021] FIG. 4 is a diagram showing an example of the configuration of the light source 21 of the present embodiment. The light source 21 is, for example, an LED (light-emitting diode), and emits light 22 in the same direction as the ejection direction (z-axis direction) of the cold air 14, that is, in the z-axis direction. The light 22 is emitted, for example, toward the skin 2 to give heat H2 to the skin 2. That is, the warm stimulation unit 20 gives a warm stimulation to the skin 2 without contact. Note that, as shown in FIG. 3, a plurality of light sources 21 may be arranged around the cold air ejection port 131 of the presentation unit 13.

[0022] In the cold sensation presentation device 1, the type of heat transfer method by which the cold stimulation unit 10 gives a cold stimulation and the type of heat transfer method by which the warm stimulation unit 20 gives a warm stimulation are different from each other. Generally, the types of heat transfer methods are classified into three: conduction, convection, and radiation. As described above, the cold stimulation unit 10 gives a cold stimulation by ejecting cold air 14 (that is, conduction or convection). The warm stimulation unit 20 gives a warm stimulation by irradiating light 22 (that is, radiation). According to the cold sensation presentation device 1 configured as described above, the cold stimulation given by the cold stimulation unit 10 and the warm stimulation given by the warm stimulation unit 20 do not interfere with each other in the space and can give stimuli independently of each other. Therefore, according to the cold sensation presentation device 1 configured as described above, it is possible to more easily control the intensity of the cold stimulation and the intensity of the warm stimulation, ignoring the mutual influence between the cold stimulation and the warm stimulation on the temperature of the skin 2.

[0023] [Time-division presentation of non-contact warm and cold stimulations] The time-division presentation of non-contact warm and cold stimulations will be described. In the description of the present embodiment, "presentation" and "display" have the same meaning.

[0024] There are two types of temperature sensations on the skin 2: static response and dynamic response. In the static response, it responds to the actual temperature on the skin surface. If the temperature on the skin surface can be changed greatly, a temperature sensation can be generated by the static response. However, when presenting a temperature sensation by the static response, it takes a long time until the sensation is generated, which is not desirable. On the other hand, in the dynamic response, it responds to the speed of temperature change. An example of the dynamic response of the skin 2 is shown in FIG. 5.

[0025] FIG. 5 is a diagram showing an example of the dynamic reaction of the skin 2. As shown in the figure, when the temperature changes rapidly, the skin 2 can perceive a small temperature change. When the temperature changes slowly, the skin 2 does not generate a temperature sensation until a large temperature change occurs. The higher the speed of the temperature change, the shorter the time for the temperature sensation to occur, and the skin 2 feels a strong stimulus.

[0026] FIG. 6 is a diagram showing an example of how the cold sensation presentation device 1 of the present embodiment applies temperature and cold stimuli. In the present embodiment, a cold stimulus stronger than the threshold perceived by the skin 2 is presented, and a warm stimulus weaker than the threshold perceived by the skin 2 is presented. After the strong cold stimulus, the skin temperature is repeatedly restored to its original state by the weak warm stimulus, thereby realizing the time-division presentation of the temperature and cold stimuli. When the temperature of the skin is changed within a range of 0.25 [°C], the subject does not feel a warm stimulus with a temperature change speed of less than 0.3 [°C / s], but feels a cold stimulus with a temperature change speed of 0.05 [°C / s] or more. The cold sensation presentation device 1 of the present embodiment utilizes the asymmetry between the speed of temperature change at which the skin 2 feels a warm stimulus and the speed of temperature change at which the skin 2 feels a cold stimulus to sustain the cold sensation in the skin 2.

[0027] [Operation of the control unit] FIG. 7 is a diagram showing an example of the operation of the control unit 30 of the present embodiment. As described above, the control unit 30 alternately repeats the cold stimulus state (for example, the cold stimulus state st1 shown in FIG. 8) and the warm stimulus state (for example, the warm stimulus state st2 shown in FIG. 8) to sustain the cold sensation in the skin 2.

[0028] Note that due to individual differences in the temperature of the subject's skin 2 in a situation where no temperature stimulus is applied, there may be individual differences in the way the cold sensation is perceived in the skin 2. Therefore, it is preferable to perform calibration for each subject with respect to the cold stimulus and the warm stimulus to obtain the temperature serving as the control reference. Also, in this case, it is preferable to store the calibration results (for example, the reference temperature for each individual) in a storage device (not shown), and the control unit 30 calculates the intensity of the cold stimulus and the intensity of the warm stimulus based on this reference temperature.

[0029] (Step S10) The control unit 30 sets the cold stimulation state st1. In the cold stimulation state st1, the control unit 30 discharges cold air 14 at a predetermined temperature and a predetermined flow rate from the presentation unit 13. Note that the control unit 30 may emit light 22 from the light source 21 while discharging the cold air 14 in the cold stimulation state st1. (Step S20) The control unit 30 sets the warm stimulation state st2. In the warm stimulation state st2, the control unit 30 emits light 22 with a predetermined light amount from the light source 21. Note that the control unit 30 may discharge the cold air 14 while emitting the light 22 from the light source 21 in the warm stimulation state st2.

[0030] FIG. 8 is a diagram showing an example of control by the control unit 30 of the present embodiment. In FIG. [A], the presentation pattern of cold stimulation by the cold stimulation unit 10 and the presentation pattern of warm stimulation by the warm stimulation unit 20 are shown separately. In FIG. [B], the result of synthesizing the presentation pattern of cold stimulation by the cold stimulation unit 10 and the presentation pattern of warm stimulation by the warm stimulation unit 20 is shown. In this example, the control unit 30 keeps the discharge temperature and discharge amount of the cold air 14 by the cold stimulation unit 10 constant in the cold stimulation state st1 and the warm stimulation state st2. Further, the control unit 30 reduces the emitted light amount of the light 22 by the warm stimulation unit 20 (weakens the light 22) in the cold stimulation state st1, and increases the emitted light amount of the light 22 by the warm stimulation unit 20 (strengthens the light 22) in the warm stimulation state st2. In the cold stimulation state st1, since no warm stimulation is presented and cold stimulation is presented, the result of synthesizing the warm stimulation and the cold stimulation is the intensity of only the cold stimulation. In the warm stimulation state st2, since the warm stimulation and the cold stimulation are presented simultaneously, the result of synthesizing the warm stimulation and the cold stimulation is that the temperature drop due to the cold stimulation is canceled out and a small temperature rise remains. As a result of presenting the cold stimulation and the warm stimulation shown in FIG. [A] and FIG. [B], the temperature of the skin changes as shown in FIG. [C].

[0031] Here, the cold stimulus state st1 is a state where the intensity of the warm stimulus is relatively small. The warm stimulus state st2 is a state where the intensity of the warm stimulus is relatively large. In other words, the intensity of the warm stimulus in the cold stimulus state st1 is smaller compared to the intensity of the warm stimulus in the warm stimulus state st2. Note that when the intensity of the warm stimulus is relatively small, as shown in FIG. [A], it also includes stopping the presentation of the warm stimulus (i.e., setting the intensity of the warm stimulus to zero). Also, when the intensity of the warm stimulus is relatively large, as shown in FIG. [A], it also includes presenting the warm stimulus while continuing to present the cold stimulus (i.e., while continuing to discharge the cold air 14). The time change of the skin temperature shown in FIG. [C] will be described in more detail with reference to FIG. 9.

[0032] FIG. 9 is a diagram showing an example of the time change of the skin temperature when the control unit 30 of the present embodiment gives the time changes of the intensities of the cold stimulus and the warm stimulus. The control unit 30 presents the cold sensation by making the time change of the intensity of the cold stimulus in the cold stimulus state st1 and the time change of the intensity of the warm stimulus in the warm stimulus state st2 different from each other, and repeating the cold stimulus state st1 and the warm stimulus state st2. As described above, the control unit 30 may emit the light 22 from the light source 21 while discharging the cold air 14 in the cold stimulus state st1. Also, the control unit 30 may discharge the cold air 14 while emitting the light 22 from the light source 21 in the warm stimulus state st2.

[0033] In the figure, from time t1 to time t3 is the cold stimulus state st1, and from time t3 to time t5 is the warm stimulus state st2. After time t5, the cold stimulus state st1 and the warm stimulus state st2 are alternately repeated. The figure shows a graph of the time change of the skin temperature in the cold stimulus state st1 and the warm stimulus state st2. As an example, when the intensity of the cold stimulus is changed from a small state to a large state so that the speed of the temperature change in the skin becomes constant, it is represented linearly like the curve c11.

[0034] Here, the control unit 30 may change the intensity of the cold stimulus over time from a relatively small state to a relatively large state in the cold stimulus state st1. As an example, the control unit 30 makes the intensity of the cold stimulus from time t2 to time t3 greater than the intensity of the cold stimulus from time t1 to time t2. In this case, the temperature of the skin changes over time as shown by curve c11. According to the cold sensation presentation device 1 configured in this way, immediately after starting to present the cold stimulus to the skin 2 (for example, between time t1 and time t2), a weaker cold stimulus is applied compared to the subsequent period (for example, between time t2 and time t3). As a result, the cold sensation presentation device 1 can make the skin 2 feel a more constant cold sensation (that is, a stable cold sensation) compared to the case where, for example, the temperature of the skin is not changed over time as shown by curve c12. Note that the control unit 30 may not change the intensity of the cold stimulus over time in the cold stimulus state st1.

[0035] Also, the control unit 30 may change the intensity of the warm stimulus over time from a relatively small state to a relatively large state in the warm stimulus state st2. As an example, the control unit 30 makes the intensity of the warm stimulus from time t3 to time t4 smaller than the intensity of the warm stimulus from time t4 to time t5. In this case, the temperature of the skin changes over time as shown by curve c23 or curve c22. According to the cold sensation presentation device 1 configured in this way, immediately after starting to present the warm stimulus to the skin 2 (for example, between time t3 and time t4), a weaker warm stimulus is applied compared to the subsequent period (for example, between time t4 and time t5). As a result, the cold sensation presentation device 1 can make it more difficult for the skin 2 to feel the warm stimulus and make it easier to perceive that the cold sensation continues.

[0036] Note that the control unit 30 may not change the intensity of the warm stimulus over time in the warm stimulus state st2. As an example, the control unit 30 does not change the intensity of the warm stimulus over time from time t3 to time t5. In this case, the temperature of the skin changes over time as shown by curve c21. According to the cold sensation presentation device 1 configured in this way, the control of the intensity of the warm stimulus can be simplified more. Further, according to the cold sensation presentation device 1 configured in this way, even if the output performance limit of the warm stimulus unit 20 is lower than when the intensity of the warm stimulus is changed over time, the device can be simplified.

[0037] Note that the intensity of the cold stimulus may be changed by changing the temperature of the fluid (cold air 14), the flow rate of the fluid, the presentation time, the energy density per unit time, and the like. Also, the intensity of the warm stimulus may be changed by changing the current value supplied to the light source 21, the number of light sources 21, the presentation time, the energy density per unit time, and the like.

[0038] Returning to FIG. 7, the description of the operation of the control unit 30 will be continued. (Step S30) The control unit 30 determines whether to end the presentation of the stimulus. When the control unit 30 determines to continue the presentation of the stimulus (Step S30; NO), the process returns to Step S10, and the cold stimulus state st1 and the warm stimulus state st2 are repeated. When the control unit 30 determines to end the presentation of the stimulus (Step S30; YES), the process proceeds to Step S40.

[0039] (Step S40) After setting to the slow cooling state st3, the control unit 30 ends the process. Here, the slow cooling state st3 is a state in which the intensity of the cold stimulus and the intensity of the warm stimulus are decreased to end the cold sensation presentation. That is, the control unit 30 decreases the intensity of the cold stimulus and the intensity of the warm stimulus to end the cold sensation presentation. According to the cold sensation presentation device 1 configured in this way, compared with the case where the cold sensation presentation is ended without decreasing the intensity of the cold stimulus and the intensity of the warm stimulus, it is possible to make the skin 2 perceive that the cold stimulus disappears more naturally. Note that in the slow cooling state st3, the control unit 30 may gradually shorten the presentation times tc and th (that is, gradually reduce the temperature change ΔT) while keeping the intensity of the cold stimulus and the intensity of the warm stimulus constant.

[0040] [Summary of Embodiment] As described above, in the cold sensation presentation device 1 of the present embodiment, both the cold stimulus unit 10 and the warm stimulus unit 20 apply temperature stimuli to the skin without contact. Therefore, according to the cold sensation presentation device 1 of the present embodiment, it is possible to hygienically present temperature stimuli in a more natural environment compared to the case of applying temperature stimuli in contact with the skin. Further, according to the cold sensation presentation device 1 of the present embodiment, since it is not affected by skin contact, it is easy to evaluate human characteristics with respect to stimuli and easy to examine the mechanism by which sensations are generated. Further, in the cold sensation presentation device 1 of the present embodiment, the control unit 30 repeats the cold stimulus state st1 and the warm stimulus state st2, thereby presenting a cold sensation with the spatial average temperature fluctuating within a small range. Here, when continuously applying a cold stimulus to the skin as in the prior art, problems such as the skin sensation becoming dull over time or the skin temperature dropping too much may occur. According to the cold sensation presentation device 1 of the present embodiment, compared to the case of continuously applying a cold stimulus, the skin sensation is less likely to become dull, the skin temperature can be reduced from dropping too much, and a cold sensation can be continuously given.

[0041] In the above-described embodiment, the cold stimulus unit 10 has been described as discharging cold air 14, but it is not limited thereto. The cold stimulus unit 10 may be, for example, a device that gives a cold stimulus by the evaporation action of misty water (for example, mist) or alcohol. Also, although the warm stimulus unit 20 has been described as being constituted by a light source 21 including an LED in the visible light band, it is not limited thereto. The warm stimulus unit 20 only needs to be able to give a warm stimulus to the skin 2 without contact, and may be, for example, a device that gives a warm stimulus by discharging warm air or irradiating infrared rays.

[0042] As described above, the cold sensation presentation device 1 of the present embodiment controls the temporal change rate of the target temperature on the skin of the subject by applying a warm stimulus and a cold stimulus to the subject. At this time, the cold sensation presentation device 1 presents a cold sensation by making the temporal change of the intensity of the cold stimulus and the temporal change of the intensity of the warm stimulus different from each other, and repeating the cold stimulus state and the warm stimulus state while keeping the intensity of the cold stimulus constant.

[0043] For example, the cold sensation presentation device 1 keeps the intensity of the cold stimulus constant by keeping the temperature and flow rate of the cold air constant. The cold sensation presentation device 1 may keep the intensity of the cold stimulus constant by keeping the temperature of the cold air constant, or may keep the intensity of the cold stimulus constant by keeping the flow rate of the cold air constant. The cold sensation presentation device 1 may keep the intensity of the cold stimulus constant by keeping both the temperature and the flow rate of the cold air constant.

[0044] Here, when the flow rate or temperature of the cold air flow changes over time, the subject may experience a sense of discomfort in the tactile sensation due to the change in the cold air flow. For example, when the flow rate of the cold air flow changes over time, it may strongly stimulate the rapidly adapting tactile receptors. In this case, the subject may experience a tactile sensation that is not originally desired. On the other hand, the cold sensation presentation device 1 of the present embodiment synthesizes warm and cold stimuli by convection and radiant heat, and provides a warm and cold sensation while keeping the cold air flow constant. As a result, according to the cold sensation presentation device 1, the tactile sensation caused by the cold air can be intentionally controlled independently of the warm and cold sensation. That is, the cold sensation presentation device 1 of the present embodiment realizes a non-contact and continuous thermal sensation without substantial temperature change or tactile discomfort.

[0045] More specifically, the cold sensation presentation device 1 of the present embodiment keeps the temperature of the ambient air before compression (for example, room temperature), the pressure of the compressed air, the flow rate of the compressed air, the cold air rate of the vortex tube 16, and the flow rate of the cold air 14 discharged from the presentation unit 13 (hereinafter also referred to as the flow rate of the presentation unit 13) constant respectively, so as to keep the intensity of the cold stimulus constant. Here, the cold air rate of the vortex tube 16 refers to the ratio of the flow rate of the cold air discharged from the vortex tube 16 to the flow rate of the compressed air 15 supplied to the vortex tube 16. In the experiment of the present embodiment, the ambient air (room temperature) before compression was set to "24 °C", the pressure of the compressed air was set to "0.6 Pa", the flow rate of the compressed air was set to "0.0012 m 3 / s", the cold air rate of the vortex tube 16 was set to "75%", and the flow rate of the presentation unit 13 was set to "0.000375 m 3 / s" (when the time change rate of the temperature was -0.08 m / s), "0.000447 m 3 / s" (when the time change rate of the temperature was -0.12 m / s), "0.000532 m 3 / s" (when the time change rate of the temperature was -0.16 m / s), "0.000625 m 3 / s" (when the time change rate of the temperature was -0.20 m / s), "0.000673 m 3 / s" (when the time change rate of the temperature was -0.24 m / s), and they were kept constant respectively. Specific experimental results will be described with reference to FIGS. 10 and 11.

[0046] FIG. 10 is a diagram showing an example of the experimental results by the cold sensation presentation device 1 of the present embodiment. FIG. 11 is a diagram showing an example of the experimental results when the cold air flow is changed over time. In FIGS. 10 and 11, the horizontal axis represents the rate of change of temperature over time (°C / s) on the skin, and the vertical axis represents the percentage (%) of the cold stimulus time out of the warm stimulus time and the cold stimulus time. The numerical values in the table indicate the percentage of subjects who answered that "the cold feeling persists". That is, the numerical values in the table indicate the percentage of subjects who felt only the cold feeling and did not experience a sense of discomfort in touch or a warm feeling. The larger the numerical value in the table, the more persistently the cold feeling is felt and the less discomfort there is.

[0047] In the case shown in FIG. 11, that is, when the cold air flow changes over time, the percentage of those who answered that "the cold feeling persists" was 83% at the maximum and 0% at the minimum. On the other hand, in the case shown in FIG. 10, that is, when there is no change in the cold air flow over time and the intensity of the cold stimulus is kept constant, the percentage of those who answered that "the cold feeling persists" was 100% at the maximum and 7% at the minimum. In particular, in the combination of the condition of the rate of change of temperature over time (horizontal axis) on the skin and the condition of the percentage of the cold stimulus time (vertical axis), the number of combinations where the percentage of those who answered that "the cold feeling persists" exceeded 70% was 2 squares in the case of FIG. 11, whereas it was 15 squares in the case of FIG. 10. The experimental results shown in FIGS. 10 and 11 indicate that the percentage of those who answered that "the cold feeling persists" is higher when the cold air flow does not change over time compared to when the cold air flow changes over time. These experimental results indicate that the cold sensation presenting device 1 of the present embodiment can give a non-contact and continuous thermal sensation to the subject while reducing the sense of discomfort in warm feeling and touch.

[0048] [Example of changing the cold stimulus] FIG. 12 is a diagram showing a modified example of the control by the control unit 30 of the present embodiment. In one example shown in FIG. 8 described above, the case where the rate of change of the target temperature over time is not changed (that is, kept constant) on the skin of the subject was described. FIG. 12 is different from the case shown in FIG. 8 in that the rate of change of the target temperature over time is changed. In [A] of the figure, the presentation pattern of the cold stimulus by the cold stimulus unit 10 and the presentation pattern of the warm stimulus by the warm stimulus unit 20 are shown separately. FIG. [B] shows the result of synthesizing the cold stimulation presentation pattern by the cold stimulation unit 10 and the warm stimulation presentation pattern by the warm stimulation unit 20. As a result of presenting the cold stimulation and the warm stimulation shown in FIGS. [A] and [B], the skin temperature changes as shown in FIG. [C]. In FIGS. 8[A] and 8[B], the cold stimulation presentation pattern and the warm stimulation presentation pattern are shown as separate graphs. On the other hand, in FIGS. 12[A] and 12[B], the cold stimulation presentation pattern and the warm stimulation presentation pattern are shown as one graph. In FIGS. 12[A] and 12[B], the origin O of the vertical axis of the graph is set as the stimulation intensity 0 (zero), and with the origin O as the boundary, the positive direction of the vertical axis indicates the direction in which the intensity of the warm stimulation is stronger, and the negative direction of the vertical axis indicates the direction in which the intensity of the cold stimulation is stronger.

[0049] In this example, the control unit 30 controls according to a weak cold state composed of a cold stimulation state st1 and a warm stimulation state st2, and a strong cold state composed of a cold stimulation state st11 and a warm stimulation state st12. The control unit 30 makes the intensity (vc10) of the cold stimulation in the strong cold state stronger than the intensity (vc1) of the cold stimulation in the weak cold state.

[0050] The control unit 30 changes the time change rate of the target temperature from the weak cold state to the strong cold state. Since the control of the control unit 30 in the weak cold state shown in the figure (that is, the cold stimulation state st1 and the warm stimulation state st2) is the same as that shown in FIG. 8, the description is omitted.

[0051] The control unit 30 keeps the discharge temperature and the discharge amount of the cold air 14 by the cold stimulation unit 10 constant in the cold stimulation state st11 and the warm stimulation state st12 in the strong cold state. Also, the control unit 30 reduces the emission light amount of the light 22 by the warm stimulation unit 20 (weakens the light 22) in the cold stimulation state st11, and increases the emission light amount of the light 22 by the warm stimulation unit 20 (strengthens the light 22) in the warm stimulation state st12. In the cold stimulation state st11, since no warm stimulation is presented and only cold stimulation is presented, the result of synthesizing the warm stimulation and the cold stimulation is the intensity of only the cold stimulation. In the warm stimulus state st12, since the warm stimulus and the cold stimulus are presented simultaneously, as a result of synthesizing the warm stimulus and the cold stimulus, the temperature decrease due to the cold stimulus is canceled out and a small temperature increase remains.

[0052] In this way, even when the control unit 30 changes the time change rate of the target temperature, the cold stimulus state and the warm stimulus state are repeated while keeping the intensity of the cold stimulus constant, thereby presenting a cold sensation. According to the cold sensation presenting device 1 of the present embodiment configured in this way, it is possible to give a non-contact and continuous thermal sensation to the subject while reducing the discomfort of the warm feeling and the tactile feeling.

[0053] Note that a part of the cold sensation presenting device 1 in each of the above-described embodiments, for example, the control unit 30 or the like, may be realized by a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed to realize it. Here, the "computer system" means a computer system built in the cold sensation presenting device 1 and includes hardware such as an OS (Operating System) and peripheral devices.

[0054] Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in a computer system. Furthermore, the "computer-readable recording medium" refers to something that holds a program dynamically for a short time, like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and also includes something that holds a program for a certain time, like a volatile memory inside a computer system serving as a server or a client in that case. Also, the above program may be for realizing a part of the aforementioned functions, and furthermore, it may be a program that can be realized in combination with a program already recorded in the computer system for realizing the aforementioned functions.

[0055] The above has described in detail an embodiment of the present invention with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the gist of the present invention.

Explanation of Reference Signs

[0056] 1... cold sensation presentation device, 10... cold stimulation part, 11... cold air generation part, 12... flow rate control part, 13... presentation part, 20... warm stimulation part, 21... light source, 30... control part

Claims

1. A cold stimulation unit that applies a cold stimulus to the skin without contact using cold air, A warm stimulation unit that applies a warm stimulus to the skin without contact, A control unit that controls the cold stimulus from the cold stimulation unit and the warm stimulus from the warm stimulation unit, Comprising, The control unit, While continuing to present the cold stimulus from the cold stimulation unit and keeping the intensity of the cold stimulus constant, the cold stimulus state in which the intensity of the warm stimulus is relatively small and the warm stimulus state in which the intensity of the warm stimulus is relatively large are alternately repeated to control the presentation of cold sensation Cold sensation presentation device.

2. The control unit, While continuing to present the cold stimulus from the cold stimulation unit and keeping the intensity of the cold stimulus constant, the cold stimulus state in which the intensity of the warm stimulus is relatively small and the warm stimulus state in which the intensity of the warm stimulus is relatively large are alternately repeated to make the temporal change of the skin temperature in the cold stimulus state different from the temporal change of the skin temperature in the warm stimulus state The cold sensation presentation device according to claim 1.

3. The control unit, After a predetermined time from the state of keeping the intensity of the cold stimulus constant while continuing to present the cold stimulus, change the intensity of at least one of the warm stimulus and the cold stimulus The cold sensation presentation device according to claim 1.

4. The control unit, By keeping the temperature and flow rate of the cold air constant, keep the intensity of the cold stimulus constant The cold sensation presentation device according to claim 1.

5. The control unit, In the warm stimulus state, change the intensity of the warm stimulus from a relatively small state to a relatively large state over time The cold sensation presentation device according to any one of claims 1 to 4.

6. The control unit, In the warm stimulus state, change the intensity of the cold stimulus from a relatively small state to a relatively large state over time The cold sensation presentation device according to any one of claims 1 to 4.

7. The control unit, Reduce the intensity of the cold stimulus and the intensity of the warm stimulus, or reduce the presentation time of the cold stimulus and the presentation time of the warm stimulus to end the cold sensation presentation The cold sensation presentation device according to any one of claims 1 to 3.

8. Among conduction, convection, and radiation, which are types of heat transfer methods, the type by which the cold stimulation unit gives the cold stimulus and the type by which the warm stimulation unit gives the warm stimulus are different from each other The cold sensation presentation device according to any one of claims 1 to 4.

9. A computer included in a control unit that controls a cold stimulation state by the cold stimulation unit and a warm stimulation state by the warm stimulation unit of a cold sensation presentation device including a cold stimulation unit that gives a cold stimulation to the skin in a non-contact manner using cold air and a warm stimulation unit that gives a warm stimulation to the skin in a non-contact manner, presenting a cold sensation by alternately repeating a cold stimulation state in which the intensity of the warm stimulation is relatively small and a warm stimulation state in which the intensity of the warm stimulation is relatively large while maintaining the intensity of the cold stimulation constant while continuing the presentation of the cold stimulation from the cold stimulation unit A program for causing the computer to execute the above.

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