COLD SENSATION PRESENTATION DEVICE AND PROGRAM

A cold sensation presentation device includes: a cold stimulus section that contactlessly gives a cold stimulus to a skin; a warm stimulus section that contactlessly gives a warm stimulus to a skin; and a control unit that presents a cold sensation by causing a temporal change in the intensity of the cold stimulus in a cold stimulus state where the intensity of the warm stimulus is relatively small and a temporal change in the intensity of the warm stimulus in a warm stimulus state where the intensity of the warm stimulus is relatively large to be different from each other, and repeating the cold stimulus state and the warm stimulus state in a state of keeping the intensity of the cold stimulus constant.

TECHNICAL FIELD

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

BACKGROUND ART

A device that gives a thermal stimulus to the skin of a subject has been proposed (e.g., Patent Document 1).

CITATION LIST

Patent Document

Patent Document 1: JP 2020-22617 A

SUMMARY OF INVENTION

Technical Problem

It is preferable that the device that gives such a thermal stimulus can continuously give the subject a natural sense of being in a real environment while artificially reproducing the real environment.

However, according to the technique as described above, since a thermal stimulus is given by being brought into contact with the skin of the subject, a natural sense cannot be given in some cases.

The present invention has been made in view of the above points, and provides a cold sensation presentation device and a program that can give a persistent cold sensation close to a real environment.

Solution to Problem

One aspect of the present invention is directed to a cold sensation presentation device including: a cold stimulus section that contactlessly gives a cold stimulus to a skin; a warm stimulus section that contactlessly gives a warm stimulus to a skin; and a control unit that presents a cold sensation by causing a temporal change in the intensity of the cold stimulus in a cold stimulus state where the intensity of the warm stimulus is relatively small and a temporal change in the intensity of the warm stimulus in a warm stimulus state where the intensity of the warm stimulus is relatively large to be different from each other, and repeating the cold stimulus state and the warm stimulus state in a state of keeping the intensity of the cold stimulus constant.

One aspect of the present invention is directed to the cold sensation presentation device in which the control unit keeps the intensity of the cold stimulus constant by keeping the temperature and the flow rate of cold air constant.

One aspect of the present invention is directed to the cold sensation presentation device in which the control unit temporally changes the intensity of the warm stimulus from a relatively small state to a relatively large state in the warm stimulus state.

One aspect of the present invention is directed to the cold sensation presentation device in which the control unit ends cold sensation presentation by gradually decreasing the intensity of the cold stimulus and the intensity of the warm stimulus or gradually decreasing presentation time of the cold stimulus and presentation time of the warm stimulus.

One aspect of the present invention is directed to the cold sensation presentation device in which among conduction, convection, and radiation, which are types of heat transfer methods, a type with which the cold stimulus section gives the cold stimulus and a type with which the warm stimulus section gives the warm stimulus are different from each other.

One aspect of the present invention is directed to a program for causing a computer that controls a cold sensation presentation device including a cold stimulus section that contactlessly gives a cold stimulus to a skin and a warm stimulus section that contactlessly gives a warm stimulus to a skin to execute causing a temporal change in the intensity of the cold stimulus in a cold stimulus state where the intensity of the warm stimulus is relatively small and the temporal change in the intensity of the warm stimulus in a warm stimulus state where the intensity of the warm stimulus is relatively large to be different from each other, and repeating the cold stimulus state and the warm stimulus state in a state of keeping the intensity of the cold stimulus constant.

Advantageous Effects of Invention

According to the present invention, it is possible to give a persistent cold sensation close to a real environment.

DESCRIPTION OF EMBODIMENTS

Background Art

Warm or cold sensation, which is a type of cutaneous sensation, plays a role of recognizing a material and a state of an object a person touches, and also plays a role of recognizing cold and warm of an environment in which the person is. Therefore, there is a possibility that a warm or cold sensation display artificially reproduces and expands a real object or an environment. Researches of transmitting thermal characteristics of an object by a contact type display using a Peltier element have been actively conducted, but if contactless warm or cold sensation control is achieved, it becomes possible to provide a sense of going to an environment such as the south pole or a tropical rainforest. Furthermore, if persistent warm or cold sensation can be provided, the sense of being in the environment becomes possible, and it is expected to lead to achievement of new sense and affect control.

In order to reproduce warm or cold sensation in a state of being immersed in the environment, not instantaneous (short time) but persistent warm or cold sensation provision is required. Many related arts are limited to instantaneous warm or cold sensation provision.

For example, instantaneous contact warm or cold sensation provision using cold water or warm water and instantaneous contactless warm or cold sensation provision using a light emitting diode (LED) are performed. An instantaneous contactless cold sensation control technique using an ultra-low temperature cold air jet has been achieved.

Embodiments

FIG.1is a view illustrating an example of a configuration of a cold sensation presentation device1of the present embodiment. In the following, where necessary, description will be given using a three-dimensional orthogonal coordinate system of the x axis, the y axis, and the z axis.

The cold sensation presentation device1includes a cold stimulus section10, a warm stimulus section20, and a control unit30.

The control unit30includes, for example, a computer that operates with a predetermined program, and controls each section of the cold sensation presentation device1.

The cold stimulus section10includes a cold air generation unit11, a flow rate control unit12, and a presentation unit13.

The cold air generation unit11generates cold air with a predetermined flow rate. The flow rate control unit12controls a flow rate of cold air generated by the cold air generation unit11.

The flow rate control unit12controls a flow rate of cold air generated by the cold air generation unit11. As an example, the flow rate control unit12includes a solenoid valve. The flow rate control unit12controls the flow rate of the cold air14by changing an opening degree of the solenoid valve to an opening degree corresponding to a pulse width modulation (PWM) current applied from the control unit.

The presentation unit13discharges, in the z axis direction, the cold air14whose flow rate has been controlled by flow rate control unit12.

The warm stimulus section20includes a light source21. The light source21emits light22having the intensity corresponding to the control of the control unit30. The warm stimulus section20may include a plurality of the light sources21.

Hereinafter, the configuration of each unit will be described more specifically.

FIG.2is a view illustrating an example of a configuration of the cold air generation unit11of the present embodiment.

As an example, the cold air generation unit11includes a vortex tube16. The vortex tube16separates compressed air15supplied from an air compressor (not illustrated) into warm air and cold air by making the compressed air15a vortex flow. Of the warm air and the cold air separated in the vortex tube16, the cold air generation unit11guides the cold air to the presentation unit13via the flow rate control unit12(not illustrated inFIG.2).

FIG.3is a view illustrating an example of the configuration of the presentation unit13of the present embodiment.

The presentation unit13includes a cold air discharge port131at a substantially center position on the xy plane. The cold air discharge port131discharges the cold air14in the z axis direction. For example, the cold air14is discharged toward skin2to take heat H1from the skin2.

That is, the cold stimulus section10contactlessly gives a cold stimulus to the skin2.

The presentation unit13may include a wall portion132having a height in the z axis direction around the cold air discharge port131. This wall portion132deters the cold air14discharged from the cold air discharge port131from diffusing in the xy plane direction.

FIG.4is a view illustrating an example of the configuration of the light source21of the present embodiment.

The light source21is, for example, a light emitting diode (LED), and emits the light22in the same direction (i.e., in the z axis direction) as the discharge direction (z axis direction) of the cold air14. The light22is emitted toward the skin2, for example, and gives heat H2to the skin2.

That is, the warm stimulus section20contactlessly gives a warm stimulus to the skin2.

As illustrated inFIG.3, the plurality of light sources21may be disposed around the cold air discharge port131of the presentation unit13.

In the cold sensation presentation device1, the type of the heat transfer method with which the cold stimulus section10gives the cold stimulus and the type of the heat transfer method with which the warm stimulus section20gives the warm stimulus are different from each other.

Generally, the heat transfer method is classified into three types of conduction, convection, and radiation. As described above, the cold stimulus section10gives a cold stimulus by discharge (i.e., conduction or convection) of the cold air14. The warm stimulus section20gives a warm stimulus by irradiation with the light22(i.e., radiation).

According to the cold sensation presentation device1thus configured, the cold stimulus given by the cold stimulus section10and the warm stimulus given by the warm stimulus section20do not interfere with each other in a space, and the cold sensation presentation device1can give stimuli independently of each other. Therefore, according to the cold sensation presentation device1thus configured, it is possible to more easily control the intensity of the cold stimulus and the intensity of the warm stimulus, ignoring a mutual influence of the cold stimulus and the warm stimulus given to the temperature of the skin2.

Time Division Provision of Contactless Warm or Cold Stimulus

Time division provision of the contactless warm or cold stimulus will be described. Note that in the description of the present embodiment, “provision” and “presentation” are synonymous.

For temperature sense of the skin2, there are two types of reactions, static reaction and dynamic reaction. The static reaction is to react to an actual temperature of the skin surface. If the temperature of the skin surface can be greatly changed, a temperature sense can be generated by the static reaction. However, in a case of providing a temperature sense by the static reaction, it takes a long time for the sense to occur, which is not desirable.

On the other hand, the dynamic reaction is to react to the rate of a temperature change. An example of the dynamic reaction of the skin2is shown inFIG.5.

FIG.5is a diagram showing an example of the human perception of temperature change of the skin2. As shown inFIG.5, when the temperature changes rapidly, the skin2can perceive a small temperature change. When the temperature changes slowly, the skin2does not have a temperature sense until a large temperature change occurs. The higher the rate of temperature change is, the shorter the time in which temperature sense occurs, and the skin2perceives a strong stimulus.

FIG.6is a view illustrating an example of a method of giving a warm or cold stimulus by the cold sensation presentation device1of the present embodiment.

In the present embodiment, a cold stimulus stronger than a perception threshold is provided to the skin2, and a warm stimulus weaker than the perception threshold is provided to the skin2. Repeating two steps of giving the strong cold stimulus and returning the skin temperature to the original temperature by the weak warm stimulus achieves time division provision of the warm or cold stimulus. When the temperature of the skin is changed within a range of 0.25 [C], a warm stimulus with the rate of temperature change of less than 0.3 [° C./s] is not preceived, and a cold stimulus with a rate of temperature change of equal to or greater than 0.05 [° C./s] is precerived.

The cold sensation presentation device1of the present embodiment sustains a cold sensation in the skin2by using asymmetry between the rate of temperature change at which the skin2perceives a warm stimulus and the rate of temperature change at which the skin2perceives a cold stimulus.

Operation of Control Unit

FIG.7is a flowchart showing an example of the operation of the control unit30of the present embodiment. As described above, the control unit30sustains the cold sensation in the skin2by alternately repeating a cold stimulus state (e.g., a cold stimulus state st1shown inFIG.8) and a warm stimulus state (e.g., a warm stimulus state st2shown inFIG.8).

Depending on individual differences in temperature of the skin2of the subject in a situation where no thermal stimulus is given, individual differences may occur in how the cold sensation is perceived on the skin2. Therefore, it is preferable to perform calibration for the cold stimulus and the warm stimulus for each subject to obtain the temperature serving as the reference of control. In this case, it is preferable that a storage device (not illustrated) store a calibration result (e.g., reference temperature for each individual), and the control unit30calculate the intensity of the cold stimulus and the intensity of the warm stimulus based on this reference temperature.

(Step S10) The control unit30sets the cold stimulus state st1. In the cold stimulus state st1, the control unit30causes the presentation unit13to discharge the cold air14having a predetermined temperature and a predetermined flow rate. In the cold stimulus state st1, the control unit30may cause the light22to be emitted from the light source21while causing the cold air14to be discharged.

(Step S20) The control unit30sets the warm stimulus state st2. In the warm stimulus state st2, the control unit30causes the light22of a predetermined light amount to be emitted from the light source21. In the warm stimulus state st2, the control unit30may cause the cold air14to be discharged while causing the light22to be emitted from the light source21.

FIG.8is a diagram showing an example of control by the control unit30of the present embodiment.

FIG.8[A] individually shows a presentation pattern of the cold stimulus by the cold stimulus section10and a presentation pattern of the warm stimulus by the warm stimulus section20.

FIG.8[B] shows a result of combining the presentation pattern of the cold stimulus by the cold stimulus section10and the presentation pattern of the warm stimulus by the warm stimulus section20.

In this example, the control unit30keeps a discharge temperature and a discharge amount of the cold air14by the cold stimulus section10constant in the cold stimulus state st1and the warm stimulus state st2. The control unit30decreases the emission amount of the light22by the warm stimulus section20(weakens the light22) in the cold stimulus state st1, and increases the emission amount of the light22by the warm stimulus section20(strengthens the light22) in the warm stimulus state st2.

In the cold stimulus state st1, since the warm stimulus is not presented and the cold stimulus is presented, the result of combining the warm stimulus and the cold stimulus is the intensity of only the cold stimulus.

In the warm stimulus state st2, since the warm stimulus and the cold stimulus are simultaneously presented, in the result of combining the warm stimulus and the cold stimulus, a temperature decrease due to the cold stimulus is canceled and a small temperature increase remains.

As a result of presentation of the cold stimulus and the warm stimulus shown inFIG.8[A] andFIG.8[B], the temperature of the skin changes as shown inFIG.8[C].

Here, the cold stimulus state st1is a state where the intensity of the warm stimulus is relatively small. The warm stimulus state st2is 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 st1is smaller than the intensity of the warm stimulus in the warm stimulus state st2.

The intensity of the warm stimulus being relatively small includes stopping presentation of the warm stimulus (i.e., making the intensity of the warm stimulus zero) as shown inFIG.8[A].

The intensity of the warm stimulus being relatively high includes presentation of the warm stimulus while continuously presenting the cold stimulus (i.e., continuously discharging the cold air14) as shown inFIG.8[A].

The temporal change of the temperature of the skin shown inFIG.8[C] will be described in more detail with reference toFIG.9.

FIG.9is a diagram showing an example of temporal change in temperature of skin when temporal changes in the intensity of a cold stimulus and the intensity of a warm stimulus are given by the control unit30of the present embodiment.

The control unit30presents a cold sensation by causing a temporal change in the intensity of the cold stimulus in the cold stimulus state st1and a temporal change in the intensity of the warm stimulus in the warm stimulus state st2to be different from each other and repeating the cold stimulus state st1and the warm stimulus state st2.

As described above, in the cold stimulus state st1, the control unit30may cause the light22to be emitted from the light source21while causing the cold air14to be discharged. In the warm stimulus state st2, the control unit30may cause the cold air14to be discharged while causing the light22to be emitted from the light source21.

InFIG.9, a period from time t1to time t3is the cold stimulus state st1, and a period from time t3to time t5is the warm stimulus state st2. After time t5, the cold stimulus state st1and the warm stimulus state st2are alternately repeated.

FIG.9shows a graph of temporal changes in the temperature of the skin in the cold stimulus state st1and the warm stimulus state st2. As an example, when the intensity of the cold stimulus is temporally changed from a small state to a large state so that the rate of temperature change in the skin becomes constant, it is represented linearly as a curve c11.

Here, in the cold stimulus state st1, the control unit30may temporally change the intensity of the cold stimulus from a relatively small state to a relatively large state.

As an example, the control unit30makes the intensity of the cold stimulus from time t2to time t3larger than the intensity of the cold stimulus from time t1to time t2. In this case, the temperature of the skin temporally changes as indicated by the curve c11. According to the cold sensation presentation device1thus configured, a weaker cold stimulus is given to the skin2immediately after the cold stimulus starts to be provided to the skin2(e.g., between time t1and time t2) as compared with the subsequent period (e.g., between time t2and time t3). As a result, the cold sensation presentation device1can cause a constant cold sensation (i.e., a stable cold sensation) to be felt by the skin2, for example, as compared with the case where the temperature of the skin is not temporally changed as shown by a curve c12.

Note that the control unit30needs not temporally change the intensity of the cold stimulus in the cold stimulus state st1.

The control unit30may temporally change the intensity of the warm stimulus from a relatively small state to a relatively large state in the warm stimulus state st2.

As an example, the control unit30makes the intensity of the warm stimulus from time t3to time t4smaller than the intensity of the warm stimulus from time t4to time t5. In this case, the temperature of the skin temporally changes as indicated by a curve c23or a curve c22. According to the cold sensation presentation device1thus configured, a weaker warm stimulus is given to the skin2immediately after the warm stimulus starts to be provided to the skin2(e.g., between time t3to time t4) as compared with the subsequent period (e.g., between time t4to time t5). As a result, the cold sensation presentation device1can cause the skin2to be less likely to feel a warm stimulus, and can cause the cold sensation to be more likely to be perceived to continue.

Note that the control unit30needs not temporally change the intensity of the warm stimulus in the warm stimulus state st2.

As an example, the control unit30does not temporally change the intensity of the warm stimulus from time t3to time t5. In this case, the temperature of the skin temporally changes as indicated by a curve c21. According to the cold sensation presentation device1thus configured, it is possible to further simplify the control of the intensity of the warm stimulus.

According to the cold sensation presentation device1thus configured, the output performance limit of the warm stimulus section20may be low as compared with a case where the intensity of the warm stimulus is temporally changed, and the device can be simplified.

The intensity of the cold stimulus may be changed by changing the temperature of the fluid (cold air14), the flow rate of the fluid, the presentation time, the energy density per unit time, and the like.

The intensity of the warm stimulus may be changed by changing the current value supplied to the light source21, the number of light sources21, the presentation time, the energy density per unit time, and the like.

Returning toFIG.7, the description of the operation of the control unit30will be continued.

(Step S30) The control unit30determines whether or not to end presentation of the stimulus. If the control unit30determines to continue presentation of the stimulus (step S30; NO), the process returns to step S10to repeat the cold stimulus state st1and the warm stimulus state st2. If the control unit30determines to end presentation of the stimulus (step S30; YES), the process proceeds to step S40.

(Step S40) The control unit30sets a slow cooling state st3, and then ends the process. Here, the slow cooling state st3is a state where the intensity of the cold stimulus and the intensity of the warm stimulus are gradually decreased to end the cold sensation presentation. That is, the control unit30gradually decreases the intensity of the cold stimulus and the intensity of the warm stimulus, and ends the cold sensation presentation. According to the cold sensation presentation device1thus configured, it is possible to cause the cold stimulus to be perceived to have disappeared more naturally in the skin2as compared with a case where the cold sensation presentation is ended without gradually decreasing the intensity of the cold stimulus and the intensity of the warm stimulus.

Note that in the slow cooling state st3, the control unit30may gradually shorten provision times tc and th (i.e., gradually decrease a temperature change ΔT) with the intensity of the cold stimulus and the intensity of the warm stimulus constant.

Summary of Embodiments

As described above, in the cold sensation presentation device1of the present embodiment, both the cold stimulus section10and the warm stimulus section20contactlessly give a thermal stimulus to the skin. Therefore, according to the cold sensation presentation device1of the present embodiment, it is possible to hygienically present a thermal stimulus in an environment closer to nature as compared with a case of giving a thermal stimulus in contact with the skin. According to the cold sensation presentation device1of the present embodiment, since it is not affected by the contact of the skin, it is easy to evaluate the characteristics of a human with respect to stimuli, and it is possible to easily examine the mechanism by which sense occurs.

In the cold sensation presentation device1of the present embodiment, the control unit30repeats the cold stimulus state st1and the warm stimulus state st2, whereby the cold sensation is presented with the spatial mean temperature fluctuating in a small range.

Here, when a cold stimulus is continuously given to the skin as in related arts, there have been cases of such problems that the sense of the skin becomes dull with the lapse of time or that the skin temperature excessively drops.

According to the cold sensation presentation device1of the present embodiment, the sense of the skin is less likely to become dull and excessive drop of the skin temperature can be reduced, and the cold sensation can be continuously given as compared with the case of continuously giving the cold stimulus.

Note that in the above embodiment, in the above embodiment, the description has been given on an assumption that the cold stimulus section10discharges the cold air14, but the present disclosure is not limited to this. The cold stimulus section10may give a cold stimulus by, for example, transpiration action of atomized water (e.g., mist), alcohol, or the like.

The description has been given on an assumption that the warm stimulus section20includes the light source21including the LED of the visible light band, but the present invention is not limited to this. The warm stimulus section20only needs to contactlessly give a warm stimulus to the skin2, and may also give a warm stimulus by discharge of warm air or irradiation with infrared rays, for example.

As described above, the cold sensation presentation device1of the present embodiment controls a temporal change rate in the target temperature on the skin of the subject by giving a warm stimulus and a cold stimulus to the subject. At this time, the cold sensation presentation device1presents a cold sensation by causing a temporal change in the intensity of the cold stimulus and a temporal change in the intensity of the warm stimulus to be different from each other and repeating the cold stimulus state and the warm stimulus state in a state of keeping the intensity of the cold stimulus constant.

For example, the cold sensation presentation device1keeps the intensity of the cold stimulus constant by keeping the temperature and the flow rate of cold air constant. The cold sensation presentation device1may 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 device1may keep the intensity of the cold stimulus constant by keeping both the temperature of the cold air and the flow rate of the cold air constant.

When the flow rate of the cold air jet and the temperature of the cold air jet temporally change, the subject may have a feeling of discomfort with the tactile sense due to the change in the cold air jet. For example, temporal change in flow rate of cold air jet may strongly stimulate rapidly adapting tactile receptors. In this case, a tactile sense that is not originally desired to be given to the subject may occur in the subject.

On the other hand, the cold sensation presentation device1of the present embodiment combines warm and cold stimuli by convection and radiant heat, and provides a warm or cold sensation while keeping a cold air jet constant. As a result, according to the cold sensation presentation device1, the tactile sense caused by cold air can be intentionally controlled independently of the warm or cold sensation.

That is, the cold sensation presentation device1of the present embodiment achieves continuous heat sensation in a contactless manner without substantial temperature change and a feeling of discomfort of tactile sensation.

More specifically, the cold sensation presentation device1of the present embodiment keeps each of the intensity of the cold stimulus constant by keeping the temperature (e.g., room temperature) of the environmental air before compressed, the pressure of the compressed air, the flow rate of the compressed air, the cold air rate of the vortex tube16, and the flow rate of the cold air14discharged from the presentation unit13(hereinafter, also described as a flow rate of the presentation unit13) constant. Here, the cold air rate of the vortex tube16refers to a proportion of the flow rate of cold air discharged from the vortex tube16to the flow rate of the compressed air15supplied to the vortex tube16.

In the experiments of the present embodiment, the environmental air before compression (room temperature) was “24° C.”, the pressure of the compressed air was “0.6 Pa”, the flow rate of the compressed air was “0.0012 m3/s”, the cold air rate of the vortex tube16was “75%”, the flow rate of the presentation unit13was “0.000375 m3/s” (when temporal change rate of temperature −0.08 m/s), “0.000447 m3/s” (when temporal change rate of temperature was −0.12 m/s), “0.000532 m3/s” (when temporal change rate of temperature was −0.16 m/s), “0.000625 m3/s” (when temporal change rate of temperature was −0.20 m/s), and “0.000673 m3/s” (when temporal change rate of temperature was −0.24 m/s), and were each kept constant.

Specific experimental results will be described with reference toFIGS.10and11.

FIG.10is a diagram showing an example of an experimental result by the cold sensation presentation device1of the present embodiment.

FIG.11is a diagram showing an example of an experimental result in a case of temporally changing a cold air jet.

InFIGS.10and11, the horizontal axes represent the temporal change rate in temperature (° C./s) in the skin, and the vertical axes represent the proportion (%) of the cold stimulus time in the warm stimulus time and the cold stimulus time. The numerical values in the tables indicate the proportion of the subjects who answered “cold sensation is sustained”. That is, the numerical values in the tables indicate the proportion of the subjects having only a cold sensation and not having a feeling of discomfort in tactile sense or having a warm sensation. The larger the numerical values in the tables, the more the cold sensation is felt sustained, and the less discomfort there is.

In the case shown inFIG.11, that is, in the case where the cold air jet temporally changes, the proportion of answering “cold sensation is sustained” was 83% at the maximum and 0% at the minimum.

On the other hand, in the case shown inFIG.10, that is, in the case where there was no temporal change in the cold air jet and the intensity of the cold stimulus was kept constant, the proportion of answering “cold sensation is sustained” was 100% at the maximum and 7% at the minimum. In particular, in the combination of the condition of the temporal change rate (horizontal axes) in temperature in the skin and the condition of the proportion (vertical axes) of cold stimulus time, the combination in which the proportion of answering “cold sensation is sustained” exceeds 70% was 2 cells in the case ofFIG.11, whereas it was 15 cells in the case ofFIG.10.

The experimental results shown inFIGS.10and11indicate that the proportion of answering “cold sensation is sustained” was higher when the cold air jet did not temporally change than when the cold air jet temporally changed.

These experimental results indicate that the cold sensation presentation device1of the present embodiment can contactlessly give continuous heat sensation to the subject while reducing the feeling of discomfort of the warm sensation and the tactile sense.

Example of Changing Cold Stimulus

FIG.12is a diagram showing a variation of control by the control unit30of the present embodiment. In the example shown inFIG.8described above, the case where the temporal change rate of the target temperature is not changed (i.e., made constant) on the skin of the subject has been described.FIG.12is different from the case shown inFIG.8in that the temporal change rate of the target temperature is changed.

FIG.12[A] individually shows a presentation pattern of the cold stimulus by the cold stimulus section10and a presentation pattern of the warm stimulus by the warm stimulus section20.

FIG.12[B] shows a result of combining the presentation pattern of the cold stimulus by the cold stimulus section10and the presentation pattern of the warm stimulus by the warm stimulus section20.

As a result of presentation of the cold stimulus and the warm stimulus shown inFIG.12[A] andFIG.12[B], the temperature of the skin changes as shown inFIG.12[C].

FIGS.8[A] and8[B] show the cold stimulus presentation pattern and the warm stimulus presentation pattern as individual graphs. On the other hand,FIGS.12[A] and12[B] show the cold stimulus presentation pattern and the warm stimulus presentation pattern as one graph. InFIGS.12[A] and12[B], origins O of the vertical axes of the graphs are defined as the stimulus intensity 0 (zero), and with the origin O as a boundary, the positive direction of the vertical axes indicates a direction in which the intensity of the warm stimulus is stronger, and the negative direction of the vertical axes indicates a direction in which the intensity of the cold stimulus is stronger.

In this example, the control unit30performs control with a weak cold state including the cold stimulus state st1and the warm stimulus state st2and a strong cold state including a cold stimulus state st11and a warm stimulus state st12. The control unit30makes the intensity (vc10) of the cold stimulus in the strong cold state stronger than the intensity (vc1) of the cold stimulus in the weak cold state.

The control unit30changes the temporal change rate of the target temperature from the weak cold state to the strong cold state. The control of the control unit30in the weak cold state (i.e., the cold stimulus state st1and the warm stimulus state st2) shown inFIG.12is similar to that in the case shown inFIG.8, and thus the description thereof is omitted.

The control unit30keeps a discharge temperature and a discharge amount of the cold air14by the cold stimulus section10constant in the cold stimulus state st11and warm stimulus state st12in the strong cold state. The control unit30decreases the emission amount of the light22by the warm stimulus section20(weakens the light22) in the cold stimulus state st11, and increases the emission amount of the light22by the warm stimulus section20(strengthens the light22) in the warm stimulus state st12.

Since the warm stimulus is not presented and the cold stimulus is presented in the cold stimulus state st11, the result of combining the warm stimulus and the cold stimulus is the intensity of only the cold stimulus.

Since the warm stimulus and the cold stimulus are simultaneously presented in the warm stimulus state st12, in the result of combining the warm stimulus and the cold stimulus, a temperature decrease due to the cold stimulus is canceled and a small temperature increase remains.

Thus, even in a case of changing the temporal change rate of the target temperature, the control unit30presents a cold sensation by repeating the cold stimulus state and the warm stimulus state in a state of keeping the intensity of the cold stimulus constant. According to the cold sensation presentation device1of the present embodiment thus configured, it is possible to contactlessly give continuous heat sensation to the subject while reducing a feeling of discomfort caused by warmness and tactile sensation.

Note that a part of the cold sensation presentation device1in each embodiment described above, for example, the control unit30and the like may be implemented by a computer. In that case, a program for implementing this function may be recorded in a computer-readable recording medium, and the program recorded in this recording medium may be read and executed by a computer system to implement the function. Note that the “computer system” mentioned here is a computer system incorporated in the cold sensation presentation device1, and includes hardware such as an operating system (OS) and peripheral devices.

In addition, the “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a CD-ROM, and a storage device such as a hard disk incorporated in a computer system. In addition, the “computer-readable recording medium” may include a recording medium that dynamically stores a program for a short period of time, such as a communication wire when the program is transmitted via a network such as the Internet or a communication line such as a telephone line, and a recording medium that stores a program for a fixed period of time, such as volatile memory inside a computer system that serves as a server or a client in the above-mentioned case. Further, the above-described program may be a program for achieving some of the above-described functions, or may be a program that can achieve the above-described functions in combination with a program that is already recorded in the computer system.

Although one embodiment of the present invention has been described above in detail with reference to the drawings, specific configurations are not limited to those described above, and various changes in design or the like may be made within the scope that does not depart from the gist of the invention.

REFERENCE SIGNS LIST