Seat temperature control device

Abstract

The present invention addresses the problem of simultaneously satisfying an alertness maintenance effect and comfort. A seat temperature regulator (100) is provided with a control device that is capable of controlling the temperature of a seat, upward and downward. The control device continually repeats heating and cooling within a temperature range of 10°C.

Description

[Technical Field]

[0001] The present disclosure relates to a seat temperature control device. [Background technology]

[0002] BACKGROUND ART Head cooling and warming devices (awakening induction devices including a headset and a temperature regulator that adjusts the temperature of the headset) have been known in the past (see, for example, Patent Document 1).

[0003] In the above-described conventional configuration, it is difficult to achieve both the effect of maintaining wakefulness and a comfortable feeling. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-125993 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-290499 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-329611 Summary of the Invention

[0005] The present disclosure has been made in consideration of the above points, and an object of the present disclosure is to provide a seat temperature control device that can achieve both the effect of maintaining wakefulness and a comfortable feeling.

[0006] A seat temperature control device according to one aspect of the present disclosure includes: a Peltier element for heating or cooling the temperature of the sheet; A control device that can control the seat temperature to heat or cool and, Equipped with The Peltier element is thermally connected to the left and right sides of the seat, and when the left side of the seat is heated, the right side of the seat is cooled, and when the left side of the seat is cooled, the right side of the seat is heated; The control device continuously repeats heating and cooling within a temperature range of 10°C. [Brief explanation of the drawings]

[0007] [Figure 1] Fig. 1A is a plan view of a seat temperature control device 100 according to the present embodiment, and Fig. 1B is a cross-sectional view of the seat temperature control device 100 taken along line AA' in Fig. 1A. [Figure 2] FIG. 2 is a block diagram of the seat temperature adjusting device 100 according to this embodiment. [Figure 3] FIG. 3 is a diagram showing an example of the installation position of the temperature adjustment section 110 in the seat temperature adjustment device 100 according to this embodiment. [Figure 4] FIG. 4 is a diagram showing the body parts of a driver sitting in the driver's seat. [Figure 5] Figure 5 shows the results of typical behaviors of seat temperature conditions and thermal sensation. [Figure 6] Fig. 6A is a diagram showing the seat temperature conditions for temperature control stimulation in which heating and cooling are repeated continuously, and Fig. 6B is a diagram showing the seat temperature conditions for constant stimulation at 24°C. [Figure 7] FIG. 7 shows the change in subjective evaluation of thermal sensation before and after the task. [Figure 8] FIG. 8 is a graph showing the change in average skin temperature under each temperature condition. [Figure 9] FIG. 9 shows the characteristics of the average arousal level across all subjects, compared across temperature conditions. [Figure 10] Figure 10A shows an example of a temperature profile for temperature control in which heating and cooling are repeatedly performed, where the temperature range and heating / cooling rate are not constant. Figure 10B shows an example of the same temperature profile, where there is an acclimatization period for the cooling stimulus. Figure 10C shows an example of the same temperature profile, where the temperature range and heating / cooling rate are constant. [Figure 11] Fig. 11A is a diagram showing the thermal sensation when the seat temperature control device 100 according to the present embodiment is maintained at 20°C, 25°C, 30°C, and 34°C, and the thermal sensation under the 20-30°C variable condition and the 25-35°C variable condition. Fig. 11B is a diagram showing the comfort / discomfort sensation when the seat temperature control device 100 is maintained at 20°C, 25°C, 30°C, and 34°C, and the comfort / discomfort sensation under the 20-30°C variable condition and the 25-35°C variable condition. [Figure 12] Fig. 12A is a block diagram of a seat temperature control device 700 which is a modified example of the seat temperature control device 100 according to the present embodiment, and Fig. 12B is a flowchart showing the operation of the modified example. [Figure 13] FIG. 13 is a diagram showing an example of pressure distribution at the contact portion between the seat and the driver when seated, detected by a pressure seat sensor. [Figure 14] Fig. 14A is a block diagram of a seat temperature control device 800 which is a modified example of the seat temperature control device 100 according to the present embodiment, and Fig. 14B is a flowchart showing the operation of the modified example. [Figure 15] Fig. 15A is a block diagram of a seat temperature control device 900 which is a modified example of the seat temperature control device 100 according to the present embodiment, and Fig. 15B is a flowchart showing the operation of the modified example. [Figure 16] Fig. 16A is a plan view of a seat temperature control device 200 which is a modified example of the seat temperature control device 100 according to the present embodiment, and Fig. 16B is a cross-sectional view of a temperature control section 210 of the seat temperature control device 200. [Figure 17] FIG. 17 is a diagram showing temperature changes in the thigh and heat transfer in the temperature adjustment unit 210. [Figure 18] FIG. 18 is a plan view of a seat temperature control device 300 which is a modified example of the seat temperature control device 100 according to the present embodiment. [Figure 19] FIG. 19 is a cross-sectional view of a temperature adjustment section 410 which is a modified example of the temperature adjustment section 110 according to this embodiment. [Figure 20] FIG. 20 is a cross-sectional view of a temperature adjustment section 510 which is a modified example of the temperature adjustment section 110 according to this embodiment. [Figure 21] 21A is a plan view of a seat temperature control device 600 which is a modified example of the seat temperature control device 100 according to the present embodiment, and FIG. [Figure 22] FIG. 22 is an enlarged cross-sectional view of a seat temperature control device 600 which is a modified example of the seat temperature control device 100 according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of a seat temperature control device according to the present disclosure will be described with reference to the drawings. Note that the embodiments disclosed below are all examples and are not intended to impose any limitations on the seat temperature control device according to the present disclosure.

[0009] Furthermore, in the embodiments disclosed below, unnecessary detailed explanations may be omitted. For example, detailed explanations of well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the explanations and to facilitate understanding by those skilled in the art.

[0010] Discomfort caused by cold sensations is caused by a sustained drop in skin temperature. Therefore, by periodically warming the skin while providing low-temperature stimulation, it is thought that excessive skin temperature drops can be prevented, thereby suppressing discomfort caused by cold sensations. Furthermore, by implementing such control, it is possible to continuously stimulate the brainstem reticular formation, which is responsible for arousal in the brain, thereby maintaining a higher level of arousal. This is based on the characteristic of the brainstem reticular formation, which responds weakly to the same stimulus but exhibits strong excitement in response to novel stimuli.

[0011] From the above, it is believed that by repeatedly stimulating with cooling and heating, it is possible to overcome the trade-off between comfort and the effect of maintaining wakefulness, which has been an issue until now, and maintain a high level of wakefulness while maintaining a higher level of comfort. Maintaining wakefulness includes both eliminating drowsiness (reducing drowsiness levels) and suppressing drowsiness (making it difficult for drowsiness levels to rise).

[0012] The seat temperature control device according to this embodiment can control the temperature of the seat to heat or cool. The chair in which the user sits is not particularly limited, and may be, for example, a chair used for desk work, studying, driving, etc. The seat is the seat in which the user sits. The seat temperature control device is installed in the seat in which the user sits. It reduces the decrease in efficiency caused by drowsiness and the risk of falling asleep while driving. Furthermore, since it is a device capable of providing a warm / cool sensation, it can also be used for purposes other than awakening. It may also be used for purposes of comfort, refreshment, and relaxation, such as providing a cool sensation in a hot environment or a warm sensation in a cold environment.

[0013] FIG. 1A is a plan view of a seat temperature control device 100 according to this embodiment. FIG. 1B is a cross-sectional view of the seat temperature control device 100 according to this embodiment. FIG. 1B is a cross-sectional view taken along dashed line A-A' in FIG. 1A. FIG. 2 is a block diagram of the seat temperature control device 100.

[0014] As shown in FIGS. 1A, 1B, and 2, the seat temperature adjustment device 100 includes a temperature adjustment section 110, a control device 130, and a switch 140.

[0015] The control device 130 is connected to the temperature adjustment unit 110 and controls the temperature of the Peltier elements 111 inside the temperature adjustment unit 110. The control device 130 can control the current value in each Peltier element 111 and reverse the direction of the current.

[0016] The switch 140 is connected to the control device 130 and has the role (function) of switching the power supply of the control device 130.

[0017] The temperature adjustment unit 110 includes a Peltier element 111 and a thermally conductive sheet 112. The temperature adjustment unit 110 is the part of the seat temperature adjustment device 100 where the actual temperature change occurs. The temperature adjustment unit 110 receives an electrical signal from the control device 130 and can change the temperature of the seat at a constant rate through the temperature change of the Peltier element 111. The temperature adjustment unit 110 is preferably disposed directly below the driver's thighs (region 120). This is because the area directly below the driver's thighs (region 120) is the part that reliably comes into contact with the seat when the driver is seated. In addition, the thighs have a large volume and heat capacity, so it takes time for the temperature to change, and the driver feels a small thermal sensation in response to a rapid cooling stimulus. Therefore, this is a preferable location for disposing the temperature adjustment unit 110, as it is less likely to cause thermal discomfort.

[0018] 1A shows a case where two temperature adjustment units 110 are provided, the temperature adjustment units 110 are not limited to the case of Fig. 1A. For example, the number of temperature adjustment units 110 is not limited to two, and may be one or three or more.

[0019] The Peltier element 111 is a heat exchange device. However, the heat exchange device is not limited to a Peltier element. For example, a device with a heat pump function can be used as the heat exchange device. The heat exchange device may be a device that combines gas compression and expansion with heat exchange, or an element that utilizes the Peltier effect. Heat exchange devices, such as a heat pump device and an element that utilizes the Peltier effect, are collectively referred to as a "heat exchange device." Peltier elements are generally rigid and prone to cracking. Therefore, embedding the Peltier element 111 inside the sheet rather than near the surface can reduce stress concentration. Furthermore, using a bent-type element as the Peltier element 111 can prevent cracking of the element. Furthermore, it is preferable to install the Peltier element 111 perpendicular to the sheet surface. This further reduces stress concentration on the Peltier element 111 and prevents cracking.

[0020] As shown in FIG. 1B , the thermally conductive sheets 112 are disposed on the upper and lower surfaces of one Peltier element 111 in the temperature adjustment unit 110. The upper and lower surfaces of the Peltier element 111 are defined as follows: one surface (first surface) of the Peltier element 111 is defined as upper surface 116, and the surface (second surface) opposite to upper surface 116 is defined as lower surface 117. For example, even when the Peltier element 111 is installed vertically, the definitions of upper and lower surfaces remain unchanged. In other words, the terms "upper" and "lower" do not refer to upper and lower surfaces in the direction perpendicular to the ground. Thus, two thermally conductive sheets 112 are disposed for one Peltier element 111. Each thermally conductive sheet 112 is disposed directly below a part of the body. In this case, "directly below a part of the body" includes the case where the thermally conductive sheet 112 is disposed on the back. In other words, "directly below" does not mean "directly below" in the direction perpendicular to the ground. The closer the thermally conductive sheet 112 is to the body, the better, in order to reduce thermal resistance. The thermally conductive sheet 112 is preferably made of a material with high thermal conductivity, such as a metal plate, particularly a copper plate or an aluminum plate. For example, it may be a carbon-based sheet, particularly a graphite sheet or a carbon nanotube sheet. For example, it may be a tubular heat pipe or a flexible heat pipe. Furthermore, since the thermally conductive sheet 112 is placed close to the body, a sheet with low rigidity does not impair user comfort. Furthermore, for the same reason, it may be breathable. In this case, the thermally conductive sheet 112 may be a mesh, woven, or sheet with punched holes for ventilation, made of a material with good thermal conductivity.

[0021] Although FIG. 1A shows a case where one temperature adjustment unit 110 is arranged to heat and cool one thigh, the arrangement of the temperature adjustment unit 110 is not limited to the arrangement shown in FIG. 1A. For example, the temperature adjustment unit 110 may be arranged as shown in FIG. 3. FIG. 3 shows an example of the installation position of the temperature adjustment unit 110 in the seat temperature adjustment device 100 according to this embodiment. The thermally conductive sheets in FIG. 3 are not all indicated by the same reference numerals, but are shown as four, namely, thermally conductive sheet 112, thermally conductive sheet 113, thermally conductive sheet 114, and thermally conductive sheet 115. The temperature adjustment unit 110 in FIG. 3 is installed so that one temperature adjustment unit 110 heats and cools both thighs.

[0022] When multiple temperature adjustment units 110 are installed, the drive control of Peltier elements 111a and 111b installed in each temperature adjustment unit 110 can be performed independently. The control device 130 can arbitrarily set the cycle for reversing the current value and direction of the current in each Peltier element 111a and 111b. For example, in FIG. 3, if the cycle for reversing the current value and direction of the current is set to be the same for one Peltier element 111a and the other Peltier element 111b, the thermally conductive sheets 112 and 114 are simultaneously heated or cooled, and the thermally conductive sheets 113 and 115 are simultaneously cooled or heated. This increases the thermal stimulation effect and promotes effective wakefulness maintenance.

[0023] Specifically, when the thermally conductive sheets 112 and 114 are heated simultaneously, the thermally conductive sheets 113 and 115 are cooled simultaneously. When the thermally conductive sheets 112 and 114 are cooled simultaneously, the thermally conductive sheets 113 and 115 are heated simultaneously.

[0024] FIG. 4 is a diagram showing the body parts of a driver sitting in the driver's seat. FIG. 4 shows the positions of the driver's back 121, waist 122, buttocks 123, and thighs 124. The location where the seat temperature control device 100 (see FIG. 2) is installed is not particularly limited as long as it is a location where the user (driver) comes into contact with the seat. If the seat temperature control device 100 is installed on the backrest of the seat, it is possible to apply hot and cold stimuli to the back 121, and if the seat temperature control device 100 is installed on the seat surface, it is possible to apply hot and cold stimuli to the buttocks and thighs 124. In particular, the thighs 124 have a large volume and a large heat capacity, so it takes time for the temperature to change, the perceived hot and cold sensation changes slowly, and they are less likely to cause thermal discomfort.

[0025] There may be multiple temperature adjustment units 110, and when there are multiple temperature adjustment units 110, the locations and timing of temperature adjustment may be different from each other. For example, the user's posture can be detected using a sheet-like pressure sensor or camera, and the location of temperature adjustment can be changed depending on the part of the body that is in contact with the sheet.

[0026] The results of an experiment on thermal sensation using the seat temperature control device 100 will be described below.

[0027] 1A and 1B. In the following description, the temperature change of the seat is given by the control device 130 of the seat temperature control device 100.

[0028] To verify the relationship between the temperature characteristics of the cooling stimulus (modulation period and temperature) and thermal sensation, we conducted an experiment in which the cooling rate and ultimate temperature were varied to assess the thermal sensation. Ten male subjects in their 20s to 50s were tested in a laboratory maintained at 24°C. The five seat temperature conditions shown in Table 1 were compared for thermal sensation over time. The initial temperature was set at 26°C, based on the comfort zone established by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers. Based on the idea that a faster cooling rate results in a less noticeable cooling sensation, three conditions were established: -1°C / min, -0.5°C / min, and the maximum cooling rate possible with this seat temperature control device (seat temperature control device 100). During the test, subjects verbally responded to the "thermal sensation" of the seat temperature control unit (temperature control unit 110) every 10 seconds, following the test supervisor's signal. Thermal sensation was rated on a nine-point scale from -4 (very cold) to 4 (very hot). This allowed us to monitor the subject's thermal sensation in real time.

[0029] [Table 1]

[0030] Figure 5 shows the results of typical behavior of thermal sensation under different seat temperature conditions. Figure 5 shows the results of condition 4 as a typical result of behavior of thermal sensation under different seat temperature conditions. The thermal sensation in Figure 5 is plotted as the average value for 10 subjects, with the vertical dotted line indicating the start point t1 and end point t2 of the temperature change. The thermal sensation begins to decrease shortly after the temperature change initiated by the control device 130, and reaches -2 (cool) when it reaches 22°C (end point t2 of the temperature change). After that, it continues to decrease despite no temperature change.

[0031] Table 1 shows the thermal sensation at the point when the specified temperature was reached (end point t2 of the temperature change) under each seat temperature condition. Comparing conditions 1 to 3, it was found that, even though the target temperature was all 20°C, conditions 2 and 3, which had a faster cooling rate, resulted in a less noticeable sensation of cold compared to condition 1. This is thought to be because the temperature change across the thighs took longer due to their large heat capacity, resulting in a slower sensation of cold. From the above, it is thought that the seat temperature can be rapidly lowered by the control device 130, and after it has dropped to the specified temperature, the temperature is raised without being maintained at a low temperature, thereby minimizing the sensation of cold and discomfort.

[0032] Furthermore, comparing conditions 3 to 5, it can be seen that the lower the ultimate temperature, the lower the thermal sensation and the colder it feels. In terms of thermal sensation, -2 means cool and is within a comfortable range, but anything below -2 is in the cold range, causing discomfort. From the above, it is believed that temperature modulation that does not cause discomfort is possible if the control device 130 controls the temperature to a cooling rate of -3°C / min and a lower limit ultimate temperature of 22°C.

[0033] From these considerations, it was determined that the optimal temperature profile for the cooling stimulus performed by the control device 130 is one in which the lower limit is 22°C and the upper limit is 26°C, with heating and cooling being continuously repeated between the upper and lower limits at a rate of change of 3°C / min.

[0034] To verify the arousal effect of the temperature control stimulus obtained by continuously repeating heating and cooling, the following experiment was conducted on subjects. The subjects were seven men in their twenties, and the changes in arousal level were compared under two different seat temperature conditions in a temperature-controlled room maintained at 22°C.

[0035] 6A and 6B show two types of sheet temperature conditions, respectively.

[0036] To control the mental load on the subjects, they sat down and performed a predetermined task for 24 minutes. The task consisted of a tracking task in which the subject used a mouse cursor to follow a regularly moving point on a display placed in front of them.

[0037] To suppress disturbance factors of alertness, the temperature conditions were 22°C ± 1°C, the illumination conditions were 100lx ± 10%, and the CO2 concentration (carbon dioxide concentration) was 1500ppm or less. The clothing conditions were standardized as long-sleeved shirts, sweatshirts, socks, and underwear. Additionally, as a precaution, subjects were instructed to ensure they had sufficient sleep the night before.

[0038] To evaluate the relationship between changes in skin surface temperature and the associated thermal sensation, skin temperature sensors were attached to various parts of the body according to the Hardy-Dubois 7-point method, and the mean skin temperature (mean skin temperature = 0.07 × head + 0.14 × forearm + 0.05 × hand + 0.35 × abdomen + 0.19 × thigh + 0.13 × lower leg + 0.07 × foot) was calculated.

[0039] Thermal sensation was subjectively assessed using a visual analogue scale (VAS) before and after the start of the task. A 10cm VAS line was used to assess the subjective degree of each question by marking the line on the line.

[0040] This indicates that without temperature control, the seat in which the subject sat would be maintained at approximately 31°C. Therefore, 31°C was used as the initial temperature in this study. In condition 1, the control device 130 cooled the seat and then continuously heated and cooled it to a temperature below the temperature before cooling, with an upper limit of 26°C and a lower limit of 22°C, and the temperature was continuously changed within a temperature range of 4°C between the upper and lower limits at a rate of ±3°C / min. In condition 2, the control device 130 cooled the seat and then applied a constant low-temperature stimulus of 24°C, which corresponds to the time-average temperature in condition 1. In both conditions, the control device 130 controlled the seat temperature to 31°C for the first 3.5 minutes, and then applied the respective temperature changes midway through the task.

[0041] The subject's level of alertness was defined on a five-point scale: "1 (not at all sleepy)," "2 (slightly sleepy)," "3 (sleepy)," "4 (quite sleepy)," and "5 (very sleepy)." Changes in alertness during the experiment were objectively quantified by raters who, after the experiment was completed, looked at the subject's facial expressions using images of the subject's face taken during the task and rated them every 5 seconds with an accuracy of 0.5 alertness.

[0042] When the time average values ​​of the measured temperatures and the total heat transfer amount were checked for the two temperature conditions presented, it was found that there was no significant difference between them, and that the control device 130 provided thermal stimulation that was thermally equivalent.

[0043] Figure 7 shows the change in subjective evaluation of thermal sensation before and after the task. Although no significant difference was found in the comparative test, the subjects in condition 2 felt cold, while the thermal sensation in condition 1 was neutral. This suggests that the stimulus used by the subjects in condition 1 did not cause discomfort due to the cold sensation.

[0044] Figure 8 shows the change in average skin temperature under each temperature condition. For each condition, the left side shows the average value for the first 3.5 minutes, and the right side shows the average value for the last 20.5 minutes of the task. Under condition 2, no significant difference was observed between the beginning and end of the task, whereas under condition 1, in which the temperature control stimulus consisted of repeated heating and cooling, there was a significant increase in average skin temperature after the stimulus was applied (average skin temperature during the second half of the task). This is consistent with the trend in thermal sensation, suggesting that thermal sensation is determined by changes in skin temperature.

[0045] Figure 9 shows the results of comparing the arousal levels obtained by facial expression ratings across all subjects, averaged across all temperature conditions. To ensure uniform arousal levels at the end of the common temperature period (3.5 minutes after the initial temperature adjustment in Figure 9), the arousal level for Condition 1 is reduced by 0.1. Conditions 1 and 2 exhibited similar upward trends until approximately 6 minutes, indicating a gradual increase in drowsiness. Condition 2 continued to rise upward, reaching a level of 3.5 (sleepy to very sleepy) at 13 minutes. In contrast, the rise in Condition 1 was gradual after 6 minutes, and the arousal level never exceeded 3.5 throughout the entire experimental period, demonstrating a reduction in drowsiness compared to Condition 2. The arousal levels for the three minutes were averaged, and the difference between the two conditions is plotted in the graph. The difference became larger after 12 minutes, with the temperature-regulating stimulation of repeated heating and cooling lowering the arousal level by 0.4 to 0.5, indicating that the arousal-maintenance effect was effective. This study was conducted in a low-temperature environment of 22°C, and it is possible to superimpose an additional effect on the low-temperature awakening effect of air conditioning. This suggests that temperature control stimulation, which involves successively repeating heating and cooling, can be expected to be used in multiple ways.

[0046] These results demonstrate that temperature control stimulation, which involves repeated heating and cooling, does not cause discomfort due to the cold sensation and has a more effective effect on maintaining wakefulness than constant low-temperature stimulation.

[0047] Figures 10A to 10C show example temperature profiles for temperature control that involves continuous heating and cooling. Figure 10A shows a case where the temperature range and heating / cooling rate are not constant, Figure 10B shows a case where there is a cooling stimulus habituation period, and Figure 10C shows a case where the temperature range and heating / cooling rate are constant. The brainstem reticular formation is responsible for arousal in the brain. Due to its characteristics, constant stimulation attenuates its excitation. On the other hand, the brainstem reticular formation is sensitive to novel stimuli. Repeated heating and cooling effectively maintains excitation of the brainstem reticular formation, thereby prolonging the state of arousal. Therefore, the temperature control that involves continuous heating and cooling refers to temperature control in which periods of heating and cooling alternate, and the time and rate of temperature change required for each do not need to be equal. Furthermore, the number of times that heating and cooling are switched (Figure 10A: Switches 1, 2, 3, ...) is not particularly limited as long as it is multiple times, but in order to repeatedly provide new stimuli, it is preferable that it be three or more times, more preferably five or more times, and even more preferably ten or more times. The temperature fluctuation range of heating and cooling indicates the difference between the highest and lowest temperatures at a series of switching points, and this fluctuation range should be sufficient to provide alternating warm and cold sensations. On the other hand, because the rate of temperature change is finite, if the temperature fluctuation range is large, heating and cooling will take longer, reducing the frequency of providing new stimuli. Therefore, the temperature fluctuation range is preferably within 10°C, more preferably within 6°C, and even more preferably within 4°C.

[0048] When switching from cooling to heating, the temperature may be switched to a temperature higher than the minimum temperature (Fig. 10B: switches 5 and 7) before reaching the minimum temperature (Fig. 10B: switches 1 and 3) as a period for getting used to the cooling stimulus. This prevents the user from being exposed to an extremely low temperature from the first time, allowing them to become accustomed to the cooling stimulus, reducing the distraction caused by being exposed to a sudden, strong cold sensation and the discomfort caused by the cold sensation.

[0049] The seat temperature control device 100 may first cool the seat, and then continuously repeat heating and cooling below the temperature before cooling (Figure 10C: temperature without temperature control). Exposure to a temperature lower than the temperature before heating and cooling is an effective awakening stimulus. This is because there are more cold spots than hot spots on the sensory receptors, and a cold sensation is a more effective awakening stimulus. The temperature range for continuously repeating heating and cooling is preferably set at a lower limit of 20°C and an upper limit of 30°C. More preferably, the lower limit is set at 22°C and an upper limit at 26°C. This is because this temperature range does not cause a strong cold or warm sensation, so there is no thermal discomfort.

[0050] The temperature change rate for temperature control, which involves successively repeating heating and cooling, is preferably 1°C / min or more, and more preferably 3°C / min or more. A change rate of 1°C or more can alleviate the cold sensation and alleviate discomfort caused by the cold sensation. Furthermore, a change rate of 3°C or more can further alleviate the cold sensation and alleviate discomfort caused by the cold sensation.

[0051] FIG. 11A shows the thermal sensations when the seat temperature control device 100 is maintained at 20°C, 25°C, 30°C, or 34°C, and under conditions of 20-30°C fluctuation and 25-35°C fluctuation. FIG. 11B shows the comfort / discomfort sensations when the seat temperature control device 100 is maintained at 20°C, 25°C, 30°C, or 34°C, and under conditions of 20-30°C fluctuation and 25-35°C fluctuation. The experimental results shown in FIGS. 11A and 11B were all obtained using the configurations shown in FIGS. 1A and 1B. FIGS. 11A and 11B show the results of subjective evaluations of thermal sensation and comfort sensation after the seat temperature control device 100 was maintained at 20°C, 25°C, 30°C, or 34°C for 10 minutes, and after the temperature was fluctuated by repeatedly heating and cooling the device in the temperature ranges of 20-30°C and 25-35°C. Table 2 shows the thermal sensation index. Table 3 shows the comfort sensation index. As can be seen from Figure 11A, the thermal sensations at 20°C, 25°C, and 30°C are slightly cooler than neutral, which is expected to have an effect of maintaining wakefulness. When the temperature range is 20°C to 30°C, the thermal sensation is lower and the discomfort is lower than when the temperature range is 25°C to 35°C. The average comfort value at all maintained temperatures in Figure 11B does not exceed 1 (slightly uncomfortable). From the results of Figures 11A and 11B, the temperature range in which the wakefulness-maintaining effect can be obtained without discomfort is a temperature range of 10°C with an upper limit of 30°C and a lower limit of 20°C.

[0052] [Table 2]

[0053] [Table 3]

[0054] The device that provides this temperature control stimulus by continuously repeating heating and cooling is not particularly limited. For example, it may be a seat temperature control device using an air conditioner, a combination of an air conditioner and an electric heater, or a device using a Peltier element. Among these, a seat temperature control device 100 using a Peltier element is one of the preferred methods because it allows for easy switching between heating and cooling, can achieve rapid temperature changes, and allows for precise temperature control.

[0055] (Variation) (Variation 1) FIG. 12A is a block diagram of a seat temperature control device 700 which is a modified example of the seat temperature control device 100 according to the present embodiment. FIG. 12B is a flowchart showing the operation of the modified example. The difference from FIG. 2 is that a determination device 750 and a drowsiness sensor 760 are used. The drowsiness sensor 760 is connected to the determination device 750. The determination device 750 is connected to the control device 730. The control device 730 is connected to the switch 740 and the determination device 750. The Peltier element 711 is connected to the control device 730.

[0056] The drowsiness sensor 760 detects the drowsiness of the user. The drowsiness sensor 760 is not particularly limited, but examples thereof include a camera, a pressure seat sensor, a motion sensor, a heart rate sensor, a pulse sensor, and a breathing sensor.

[0057] The determination device 750 determines the drowsiness level based on user information obtained from the drowsiness sensor 760. The determination device 750 may also determine the drowsiness level based on user information obtained from multiple sensors, not limited to the drowsiness sensor 760. The drowsiness level may be determined based on the user's drowsiness level at a certain point in time between the past and the present, based on past accumulated information and current information, or may be a predicted drowsiness level at a certain point in the future. The determination method is not particularly limited, and may be determined based, for example, on the user's blink count obtained from a camera or changes in the user's center of gravity obtained from a pressure sheet sensor. FIG. 13 shows an example of the pressure distribution of the contact area with the seat when seated, detected by the pressure sheet sensor. In FIG. 13, darker areas indicate higher pressure, and lighter areas indicate lower pressure. The dotted line in FIG. 13 indicates the location of the temperature adjustment unit 110. The pressure sheet sensor is installed in the seat and acquires the distribution of contact pressure between the user and the seat over time. For example, it can be determined that the user's discomfort has increased when the contact pressure between the user and the seat decreases after the temperature adjustment has started. This is because the user will feel uncomfortable and will reseat so that their thighs are further away from the temperature adjustment unit 110. There are no particular limitations on the pressure sheet sensor, and it may detect pressure as a change in resistance value or a change in capacitance. Figure 13 shows the results of an experiment using a capacitance-type pressure sheet sensor.

[0058] As shown in FIG. 12B, after starting (S700), the seat temperature control device 700 turns on the power of the drowsiness sensor 760 (S701) and determines whether the power of the switch 740 is ON / OFF (S702). Next, if the switch 740 is OFF (S702), the process ends (S703). If the switch 740 is ON (S702), the determination device 750 determines whether the drowsiness level is equal to or higher than a threshold (S704). If the determination device 750 detects a drowsiness level equal to or higher than the threshold, the seat temperature control device 700 starts a hot / cold stimulus to relieve the user of drowsiness (S705). If the determination device 750 detects a drowsiness level lower than the threshold, the seat temperature control device 700 does not perform the hot / cold stimulus, and the drowsiness sensor 760 returns to the monitoring state.

[0059] (Variation 2) FIG. 14A is a block diagram of a seat temperature control device 800 which is a modified example of the seat temperature control device 100 according to the present embodiment. FIG. 14B is a flowchart showing the operation of the modified example. The difference from FIG. 2 is that a determination device 850, a drowsiness sensor 860, and a notification device 870 are used. The notification device 870 is connected to a control device 830. A Peltier element 811 is connected to the control device 830. The drowsiness sensor 860 is connected to the determination device 850. The determination device 850 is connected to the control device 830. The control device 830 is connected to a switch 840 and the determination device 850.

[0060] The notification device 870 notifies the user in advance of the start of temperature control by the seat temperature control device 800. If the seat temperature control device 800 starts temperature control without notifying the user, the user may be surprised by the sudden temperature change or confused due to the discomfort, which may compromise driving safety. By notifying the user in advance of the start of temperature control, the notification device 870 can prevent confusion among the user. The notification means of the notification device 870 is not particularly limited, but may include, for example, audio, video, a lamp, and vibration. If the notification means of the notification device 870 is audio, the speaker of the notification device 870 notifies the user that the drowsiness level is increasing and that seat temperature control will be started to alleviate the drowsiness.

[0061] As shown in FIG. 14B, after starting (S800), the seat temperature control device 800 turns on the power of the drowsiness sensor 860 (S801) and determines whether the power of the switch 840 is ON or OFF (S802). Next, if the switch 840 is OFF (S802), the process ends (S803). If the switch 840 is ON (S802), the determination device 850 determines whether the drowsiness level is equal to or higher than a threshold (S804). If the determination device 850 detects a drowsiness level equal to or higher than the threshold, the notification device 870 issues a prior notification of the start of temperature control (S805). Next, the seat temperature control device 800 starts a hot / cold stimulus to relieve the user of drowsiness (S806). Furthermore, if the determination device 850 detects a drowsiness level below the threshold, the seat temperature control device 800 does not provide a hot / cold stimulus, and the drowsiness sensor 860 returns to the monitoring state.

[0062] (Variation 3) FIG. 15A is a block diagram of a seat temperature control device 900 which is a modified example of the seat temperature control device 100 according to the present embodiment. FIG. 15B is a flowchart showing the operation of the modified example. The difference from FIG. 2 is that a determination device 950, a drowsiness sensor 960, a discomfort determination device 980, and a discomfort sensor 990 are used. The discomfort sensor 990 is connected to the discomfort determination device 980. The Peltier element 911 is connected to the control device 930. The determination device 950 is connected to the control device 930. The discomfort determination device 980 is connected to the control device 930. The control device 930 is connected to a switch 940 and the determination device 950.

[0063] The discomfort sensor 990 acquires the user's discomfort. For example, the discomfort sensor 990 that acquires the user's discomfort may be a pressure seat sensor that can acquire the contact pressure between the user and the seat. This is because if the temperature conditions of the seat temperature adjustment device 900 are uncomfortable, the user will reduce the contact pressure with the seat. The discomfort sensor 990 may also be a camera-based user posture monitor. This is because if the temperature conditions of the seat temperature adjustment device 900 are uncomfortable, the user will move their body away from the seat temperature adjustment device 900.

[0064] The discomfort determination device 980 outputs the discomfort level from the data obtained from the discomfort sensor 990. When the discomfort level is equal to or greater than a threshold, the control device 930 reduces the upper and lower temperature limits of the temperature control that continuously repeats heating and cooling, thereby mitigating the thermal stimulation.

[0065] As shown in FIG. 15B, after starting (S900), the seat temperature control device 900 turns on the drowsiness sensor 960 (S901), turns on the discomfort sensor 990 (S902), and determines whether the switch 940 is on or off (S903). Next, if the switch 940 is off (S903), the process ends (S904). If the switch 940 is on (S903), the determination device 950 determines whether the drowsiness level is equal to or higher than a threshold (S905). If the determination device 950 detects a drowsiness level equal to or higher than the threshold, the seat temperature control device 900 starts a hot / cold stimulus to relieve the user of drowsiness (S906). Next, the discomfort determination device 980 determines whether the discomfort level is equal to or higher than a threshold (S907). If the discomfort determination device 980 detects an discomfort level equal to or higher than the threshold, the control device 930 changes the temperature conditions (S908).

[0066] (Variation 4) FIG. 16A is a plan view of a seat temperature control device 200, which is a modified example of the seat temperature control device 100 according to the present embodiment. FIG. 16B is a cross-sectional view of a temperature control unit 210 of the seat temperature control device 200. FIG. 16B is a cross-sectional view taken along the dashed line A-A' in FIG. 16A. The difference between the seat temperature control device 100 and the seat temperature control device 200 is that the seat temperature control device 200 uses only one temperature control unit 210. The temperature control unit 210 includes a Peltier element 211 and a heat-conducting sheet 212. However, the heat exchange means is not limited to a Peltier element, and any heat exchange device may be used. The heat-conducting sheet 212 is located directly below the thighs (region 220), which is the area that reliably comes into contact with the seat when the driver is seated. A control device is connected to the Peltier element 211, which can control the seat to heat or cool by changing the temperature of the Peltier element 211.

[0067] FIG. 17 shows temperature changes in the thigh and heat transfer in the temperature adjustment unit 210 (see FIG. 16A). The Peltier element 211 (see FIG. 16A) can switch between heat absorption and heating by switching the direction of current. This makes it possible not only to constantly cool or heat, but also to continuously repeat cooling and heating. As a result, the temperature adjustment unit 210 repeatedly applies cooling and heating stimuli, which effectively activates the brainstem reticular formation, which is sensitive to novel stimuli, and enhances the awakening effect. The time for switching the direction of current does not need to be an evenly spaced cycle.

[0068] When an electric current is passed through the Peltier element 211, the Peltier element 211 absorbs heat from one side (cooling) and transfers it to the opposite side (heating). The thermally conductive sheets 212 are connected to the top and bottom of the Peltier element 211, respectively. The thermally conductive sheets 212 connected to the top and bottom of the Peltier element 211 are configured to extend in opposite directions. This configuration allows the two thermally conductive sheets 212 to simultaneously achieve a state in which one thermally conductive sheet 212 is warm and the other thermally conductive sheet 212 is cold, or vice versa. This is thought to increase the awakening effect, as one of the left and right thighs becomes cool and the other warm. The temperature adjustment unit 210 absorbs heat from one part of the body and transfers the absorbed heat to another part of the body, thereby creating a temperature difference on the skin surface. This structure allows waste heat to be used for heating, which is thought to improve energy efficiency.

[0069] (Variation 5) FIG. 18 is a plan view of a seat temperature control device 300, which is a modified example of the seat temperature control device 100 according to the present embodiment. The difference between the seat temperature control device 100 and the seat temperature control device 300 is that the seat temperature control device 300 uses only one temperature control unit 310. The temperature control unit 310 includes a Peltier element 311 and a heat-conducting sheet 312. However, the heat exchange means is not limited to a Peltier element, and any heat exchange device may be used. The heat-conducting sheet 312 is disposed directly below the thighs (area 320), which are areas that are in reliable contact with the seat when the driver is seated. The heat-conducting sheets 312 connected to the upper and lower surfaces of the Peltier element 311 are not limited to extending in opposite directions, and may be disposed as shown in FIG. 18, for example. The Peltier element 311 is connected to a control device that can heat or cool the seat through temperature changes in the Peltier element 311.

[0070] (Variation 6) 19 is a cross-sectional view of a temperature adjustment unit 410, which is a modified example of the temperature adjustment unit 110 according to the present embodiment. The difference between the temperature adjustment unit 110 and the temperature adjustment unit 410 is that the temperature adjustment unit 410 includes a fan 413. The temperature adjustment unit 410 includes a Peltier element 411, a heat conduction sheet 412, and a fan 413. However, the means for heat exchange is not limited to a Peltier element, and any heat exchange device may be used. By placing the Peltier element 411 perpendicular to the surface of the heat conduction sheet 412, stress concentration on the Peltier element 411 can be reduced, and cracks can be suppressed. By including the fan 413, the temperature adjustment unit 410 can efficiently dissipate heat.

[0071] (Variation 7) FIG. 20 is a cross-sectional view of a temperature adjustment unit 510, which is a modified example of the temperature adjustment unit 110 according to the present embodiment. The difference between the temperature adjustment unit 110 and the temperature adjustment unit 510 is that the temperature adjustment unit 510 includes a fan 513 and heat dissipation fins 514. The temperature adjustment unit 510 includes a Peltier element 511, a heat conduction sheet 512, a fan 513, and heat dissipation fins 514. However, the heat exchange means is not limited to a Peltier element, and any heat exchange device may be used. By placing the Peltier element 511 perpendicular to the surface of the heat conduction sheet 512, stress concentration on the Peltier element 511 can be reduced, thereby preventing cracks. The Peltier element 511 may be provided with heat dissipation fins 514 and a fan 513 to achieve accurate temperature control. The temperature adjustment unit 510 uses the heat dissipation fins 514 to efficiently exchange heat.

[0072] (Variation 8) FIG. 21A is a plan view of a seat temperature control device 600, which is a modified example of the seat temperature control device 100 according to the present embodiment. FIG. 21B is a cross-sectional view of a temperature control unit 610 of the seat temperature control device 600. FIG. 21B is a cross-sectional view taken along the dashed line A-A' in FIG. 21A. The seat temperature control device 600 differs from the seat temperature control device 100 in that the seat temperature control device 600 uses only one temperature control unit 610 and only one thermally conductive sheet 612. The temperature control unit 610 includes a Peltier element 611 and a thermally conductive sheet 612. However, the heat exchange means is not limited to the Peltier element 611 and may be any heat exchanger. The thermally conductive sheet 612 is located directly below the thighs (region 620), which is the area that reliably comes into contact with the seat when the driver is seated. The Peltier element 611 is connected to a control device that can heat or cool the seat through temperature changes in the Peltier element 611.

[0073] FIG. 22 is an enlarged cross-sectional view of a seat temperature control device 600, which is a modified example of the seat temperature control device 100 according to the present embodiment. The seat temperature control device 600 is disposed directly below the right thigh 630 and the left thigh 640. Furthermore, a Peltier element 611 is disposed directly below the left thigh 640, and a thermally conductive sheet 612 is connected to the underside of the Peltier element 611. The portion of the thermally conductive sheet 612 not connected to the Peltier element 611 is disposed so as to be located directly below the right thigh 630. However, the body parts are not specified, as long as the Peltier element 611 is disposed directly below a part of the body (a first part) and the thermally conductive sheet 612 is disposed so as to be located directly below another part of the body (a second part). In FIG. 22, for example, when the upper surface of the Peltier element 611 is controlled to be warm and the lower surface is controlled to be cool, the Peltier element 611 absorbs heat from the lower surface and warms the upper surface. Because the thermally conductive sheet 612 is connected to the underside of the Peltier element 611, heat transfer occurs in the direction of the arrow shown in FIG. 22, absorbing heat from the right thigh 630. As a result, the upper surface of the Peltier element 611 becomes warm, warming the left thigh 640. Meanwhile, the right thigh 630, from which heat has been absorbed, is cooled. The seat temperature control device 600 can simultaneously achieve a warm state for the left thigh 640 and a cool state for the right thigh 630, or vice versa, which is thought to increase the awakening effect. The temperature control unit 610 absorbs heat from one part of the body and transfers the absorbed heat to another part of the body, thereby creating a temperature difference on the skin surface. This structure allows waste heat to be used for heating, which is thought to improve energy efficiency.

[0074] The seat temperature control device according to the embodiment and each modification can achieve both the effect of maintaining wakefulness and a comfortable feeling, and can therefore be used, for example, in the driver's seat, and can achieve both the effect of maintaining wakefulness and a comfortable feeling for the driver. [Industrial Applicability]

[0075] The seat temperature control device of the present disclosure can be used, for example, in the driver's seat. [Explanation of symbols]

[0076] 100, 200, 300, 600, 700, 800, 900 Seat temperature control device 110, 210, 310, 410, 510, 610 Temperature control section 111, 211, 311, 411, 511, 611, 711, 811, 911 Peltier elements 112, 113, 114, 115, 212, 312, 412, 512, 612 Thermal Conductive Sheet 116 Top surface 117 Bottom side 120, 220, 320, 620 Area just below the thigh 630 Right thigh 640 Left thigh 121 Back 122 Waist 123 Butt 124 Thigh 130, 730, 830, 930 control device 140, 740, 840, 940 Switches 413, 513 Fan 514 Heat dissipation fin 750, 850, 950 judgment device 760, 860, 960 Drowsiness Sensor 870 Notification device 980 Discomfort Judgment Device 990 Discomfort Sensor

Claims

1. A Peltier element for heating or cooling the temperature of a seat; a control device capable of controlling the temperature of the seat to heat and cool, The Peltier element is thermally connected to the left and right sides of the seat, and when the left side of the seat is heated, the right side of the seat is cooled, and when the left side of the seat is cooled, the right side of the seat is heated; The control device continuously repeats heating and cooling within a temperature range of 10°C. Seat temperature control device.

2. The control device continuously repeats heating and cooling within a temperature range of 4°C. The seat temperature control device according to claim 1 .

3. The control device has a lower limit temperature of 20°C and an upper limit temperature of 30°C, and continuously repeats heating and cooling between the upper and lower limits at a rate of change of 1°C / min or more. The seat temperature control device according to claim 1 or 2.

4. The control device has a lower limit temperature of 22°C and an upper limit temperature of 26°C, and continuously repeats heating and cooling between the upper and lower limits at a rate of change of 3°C / min or more. The seat temperature control device according to any one of claims 1 to 3.

5. At least one sensor for detecting drowsiness of a user; a determination device that determines a drowsiness level of the user based on information from the sensor, The control device performs control based on information from the determination device. The seat temperature control device according to any one of claims 1 to 4.

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