JP2011220642A - Cooling device, and image display apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cooling device, along with an image display apparatus, capable of reducing stagnation in the circulation of a working liquid.SOLUTION: The cooling device includes: a cooling block; a heat pipe in which the working liquid is enclosed, and whose external wall is configured such that one end thereof is connected to a heat source and the other is connected to the cooling block; a plurality of Peltier element units arranged along the longitudinal direction of the heat pipe so as to cool the heat pipe through the cooling block; and a control unit configured to control the plurality of the Peltier element units such that, according to the amount of heat transfer from the heat source of the heat pipe to the cooling block, the plurality of the Peltier element units are to be driven in order from the unit closest to the heat source.

Description

  The present invention relates to a cooling device and an image display device.

  Conventionally, a cooling apparatus that performs cooling using a plurality of Peltier elements has been proposed.

  In Patent Document 1, in a heat exchange device, a heat medium supplied from an inlet pipe is cooled (or heated) by a plurality of heat exchangers connected in series, and a heat medium having a predetermined temperature is output from the outlet pipe. It is described. In each heat exchanger, a plurality of Peltier elements are installed on both side surfaces of a plate-type heat exchanger through which a heat medium passes. The heat medium flowing through each heat exchanger is cooled (or heated) by controlling the direction of the current supplied to each Peltier element so that the side facing the plate heat exchanger absorbs heat (or dissipates heat). In addition, a DC power supply circuit that supplies power to the Peltier element is provided for each heat exchanger, and the control unit controls the number of heat exchangers that are effective by controlling each DC power supply circuit on and off according to the thermal load. Thus, according to Patent Document 1, it is possible to reduce the number of DC power supply circuits that are operated for temperature control of the heat medium, and to reduce power loss due to the DC power supply circuit. Yes.

  Patent Document 2 describes a temperature control device that controls a plurality of thermo modules. Specifically, a Peltier element is used for each thermo module. The temperature control device selects one thermo module and detects its temperature. When the temperature of the thermo module rises (or falls) from the set temperature, the pulse voltage in the direction of cooling (or heating) can be varied. Supply from the power supply unit to the Peltier element of the thermo module. Thus, according to Patent Document 2, since a plurality of thermo modules are pulse-driven by a single variable power source, it is said that the apparatus can be reduced in size and weight.

JP 2001-108328 A JP 2001-153485 A

  Patent Documents 1 and 2 have no description regarding providing a heat pipe in which a working fluid is sealed.

  On the other hand, in the cooling device provided with the heat pipe, when the heat amount close to the limit of the heat transport amount of the heat pipe is transported from the heat source side to the cooling unit side, the working fluid enclosed in the heat pipe is transferred to the cooling unit side. A phenomenon may occur in which the tip portion accumulates. This phenomenon is likely to occur when the plurality of cooling parts of the heat pipe are in a horizontal posture or below the heat source. When this phenomenon occurs, the circulation of the working fluid inside the heat pipe is delayed and the working fluid does not recirculate to the heat source side. Further, the portion where the hydraulic fluid is accumulated (tip portion) is cooled by the cooling portion on the tip portion side in a state where no heat flow is supplied because the vapor does not reach, and the temperature is lower than the portion where the other cooling portions are cooled. . Since this portion (tip portion) is excessively cooled without contributing to the cooling of the heat source, the power efficiency of the Peltier element is significantly reduced. A vicious cycle in which the hydraulic fluid does not return further because vapor condensation is promoted at the tip that has become low temperature may occur, and eventually the hydraulic fluid near the heat source may be exhausted, causing the temperature of the heat source to rise rapidly There is.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a cooling device and an image display device that can reduce the stagnation of working fluid circulation.

  In order to solve the above-described problems and achieve the object, a cooling device according to one aspect of the present invention includes a cooling block, a working fluid enclosed therein, and one end side of the outer wall connected to a heat source. A heat pipe having an end connected to the cooling block, a plurality of Peltier element units arranged along the longitudinal direction of the heat pipe so as to cool the heat pipe via the cooling block, and the heat pipe A control unit that controls driving of the plurality of Peltier element units so as to sequentially drive the plurality of Peltier element units from the side close to the heat source in accordance with the amount of heat transport from the heat source side to the cooling block side. It is characterized by comprising.

  According to the present invention, when the endothermic amount on the cooling side by the plurality of Peltier element units is close to the maximum heat transport amount of the heat pipe, it is possible to reduce the excessive cooling of the cooling-side tip portion inside the heat pipe. The As a result, the phenomenon that the working fluid stays at the cooling-side tip inside the heat pipe is suppressed, and the circulation of the working fluid can be reduced.

FIG. 1 is a diagram illustrating a configuration of the cooling device according to the first embodiment. FIG. 2 is a graph illustrating an example of a driving state of the Peltier element unit with respect to the heat transport amount of the cooling device according to the first embodiment. FIG. 3 is a perspective view of the cooling device according to the second embodiment. FIG. 4 is a sectional view of the cooling device according to the third embodiment. FIG. 5 is a cross-sectional view of the cooling device according to the fourth embodiment. FIG. 6 is a cross-sectional view of the cooling device according to the fifth embodiment. FIG. 7 is a cross-sectional view illustrating the cooling device according to the sixth embodiment. FIG. 8 is a diagram illustrating an image display apparatus according to the seventh and eighth embodiments. FIG. 9 is a graph illustrating an example of a driving state of the Peltier element unit with respect to the heat transport amount of the cooling device according to the comparative example.

  Embodiments of a cooling device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
The configuration of the cooling device 100 according to the first embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration (cross-sectional configuration or functional configuration) of a cooling device 100 according to the first embodiment.

  The cooling device 100 includes a heat pipe 1, a cooling unit block (cooling block) 3, a plurality of Peltier element units 4 a to 4 d, a heat radiating unit block 5, a control device (control unit) 7, and temperature sensors 8 and 9.

  The heat pipe 1 is provided with a heat source 2 on one side and a cooling unit block 3 on the other side. That is, the heat pipe 1 has an outer wall 1a and an inner flow path 1b. The outer wall 1a extends in the lateral direction in FIG. One end side 1 a 1 of the outer wall 1 a is connected to the heat source 2. The other end 1 a 2 of the outer wall 1 a is connected to the cooling unit block 3. The internal flow path 1b is a closed space surrounded by the outer wall 1a. A working fluid is sealed in the internal flow path 1b. The hydraulic fluid is a liquid that evaporates and condenses within a predetermined temperature range corresponding to the temperature of the heat source 2 and the temperature of the cooling unit block 3 and circulates in the internal flow path 1b.

  The cooling unit block 3 extends along the longitudinal direction of the heat pipe 1. One main surface of the cooling unit block 3 is connected to one end side 1a1 of the outer wall 1a. A plurality of Peltier element units 4 a to 4 d are connected to a main surface opposite to one main surface in the cooling unit block 3. Thereby, the cooling unit block 3 includes a plurality of cooling units 3 a to 3 d for cooling the heat pipe 1.

  The plurality of Peltier element units 4 a to 4 d are arranged along the longitudinal direction of the heat pipe 1 so as to cool the heat pipe 1 via the cooling unit block 3. That is, the cooling unit block 3 is attached (connected) to the heat absorbing surfaces of the Peltier element units 4a to 4d. The heat radiating part block 5 is attached (connected) to the heat radiating surface of each Peltier element unit 4a-4d. Although four Peltier element units are arranged in FIG. 1, the number is not limited as long as it is two or more.

  The heat radiation block 5 extends along the longitudinal direction of the heat pipe 1. A plurality of Peltier element units 4 a to 4 d are connected to one main surface of the heat radiating unit block 5.

  The control device 7 is connected to a plurality of Peltier element units 4a to 4d via a plurality of control lines 6a to 6d. The control device 7 drives each Peltier element unit 4a-4d by supplying electric power to the corresponding Peltier element unit 4a-4d via each control line 6a-6d.

  Specifically, the control device 7 sequentially gives priority to the plurality of Peltier element units 4a to 4d from the side close to the heat source 2 according to the amount of heat transport from the heat source 2 side of the heat pipe 1 to the cooling block 3 side. The driving of the plurality of Peltier element units 4a to 4d is controlled so as to start driving. Further, the control device 7 sequentially drives the plurality of Peltier element units 4a to 4d with priority from the side far from the heat source 2 according to the amount of heat transport from the heat source 2 side to the cooling block 3 side of the heat pipe 1. The driving of the plurality of Peltier element units 4a to 4d is controlled so as to finish.

  The temperature sensor 8 measures the temperature of the heat pipe 1 near the cooling unit 3a, for example, and supplies the measurement result to the control device 7. The temperature sensor 9 measures the temperature of the heat pipe 1 near the heat source 2 and supplies the measurement result to the control device 7. Thereby, the control apparatus 7 determines the electric power supplied to each Peltier element unit 4a-4d from the measurement result of the temperature sensor 8 or 9, and controls the drive of each Peltier element unit 4a-4d.

  The temperature sensor 8 and the temperature sensor 9 can be controlled by the control device 7 as long as at least one of them is attached. For example, in the case of a projection-type image display device using a laser element, if the thermal resistance between the heat pipe 1 and the laser element (heat source 2) is constant, the temperature sensor 9 is attached to the laser element (heat source 2). Instead, for example, the temperature sensor 8 may be arranged in the vicinity of the cooling unit 3a.

  Here, suppose a case where the control device 7 controls driving of the plurality of Peltier element units 4a to 4d so as to start driving the plurality of Peltier element units 4a to 4d simultaneously. In this case, after the drive by the control device 7 is started, the amount of heat transport from the one end side 1a1 of the outer wall 1a to the other end side 1a2 by the hydraulic fluid sealed in the internal flow path 1b of the heat pipe 1 gradually increases. At this time, as shown in FIG. 9, the endothermic amounts Qa1 to Qd1 by the Peltier element units 4a to 4d increase simultaneously. When the heat amount close to the limit of the heat transport amount of the heat pipe 1 (for example, the region R1 having a heat transport amount of 80 to 100% shown in FIG. 9) is transported from the heat source side to the cooling unit side, A phenomenon may occur in which the hydraulic fluid sealed in is accumulated at the front end 1b1 on the cooling unit 3d side in the internal flow path 1b. This phenomenon is likely to occur when the plurality of cooling units 3a to 3d of the heat pipe 1 are in a posture that is almost horizontal or the heating unit is above. When this phenomenon occurs, the circulation of the working fluid inside the heat pipe 1 is delayed and the working fluid does not recirculate to the heat source 2 side. Further, the portion where the hydraulic fluid is accumulated (tip portion 1b1) corresponds to the vicinity of the maximum electric power (for example, the heat absorption amount is 80 to 100%) by the cooling portion 3d on the tip portion 1b1 side in a state where no heat flow is supplied because the steam does not reach. The other cooling parts 3a to 3c are cooled to a lower temperature than the part being cooled. Since this portion (tip portion 1b1) is excessively cooled without contributing to the cooling of the heat source 2, the power efficiency of the Peltier element is significantly reduced. A vicious cycle occurs in which the working fluid does not return because the vapor condensation is promoted at the tip 1b1 that has become low temperature, and the temperature of the heat source 2 suddenly rises due to the exhaustion of the working fluid near the heat source 2. there's a possibility that.

  On the other hand, in the first embodiment, the plurality of Peltier element units 4a to 4d are sequentially driven from the side close to the heat source 2 in accordance with the amount of heat transport from the heat source 2 side of the heat pipe 1 to the cooling block 3 side. In this way, the driving of the plurality of Peltier element units 4a to 4d is controlled. In this case, after the drive by the control device 7 is started, the amount of heat transport from the one end side 1a1 of the outer wall 1a to the other end side 1a2 by the hydraulic fluid sealed in the internal flow path 1b of the heat pipe 1 gradually increases. At this time, as shown in FIG. 2, the heat absorption amounts Qa to Qd by the respective Peltier element units 4a to 4d are sequentially increased.

  For example, when the design maximum heat absorption amount of each Peltier element unit 4a to 4d is 100%, the driving power of the Peltier element unit 4a is reduced to 0 as the heat transport amount of the heat pipe 1 required for cooling increases. % To a value corresponding to 100% of the endothermic amount. Thereafter, the driving power of the Peltier element unit 4b is increased from a value corresponding to the endothermic amount 0% to a value corresponding to the endothermic amount 100%. Thereafter, the driving power of the Peltier element unit 4c is increased from a value corresponding to the endothermic amount 0% to a value corresponding to the endothermic amount 100%. Thereafter, the driving power of the Peltier element unit 4d is increased from a value corresponding to the endothermic amount 0% to a value corresponding to the endothermic amount 100%. In this way, the driving power is sequentially increased from the Peltier element unit close to the heat source 2.

  When reducing the power from the maximum drive power state, the drive power of the Peltier element unit 4a is reduced from a value corresponding to the endothermic amount 100% to a value corresponding to the endothermic amount 0%. Thereafter, the driving power of the Peltier element unit 4b is reduced from a value corresponding to the endothermic amount 100% to a value corresponding to the endothermic amount 0%. Thereafter, the driving power of the Peltier element unit 4c is reduced from a value corresponding to the endothermic amount 100% to a value corresponding to the endothermic amount 0%. Thereafter, the driving power of the Peltier element unit 4d is reduced from a value corresponding to the endothermic amount 100% to a value corresponding to the endothermic amount 0%. In this way, the driving power is sequentially reduced from the Peltier element unit far from the heat source 2.

  As shown in FIG. 2, by controlling the power of the Peltier element unit 4d, the vicinity of the tip 1b1 in the internal flow path 1b of the heat pipe 1 is near the maximum power (for example, power corresponding to an endothermic amount of 80 to 100%). The driving is limited when the vicinity of the designed maximum heat transport amount of the Peltier element unit 4d (for example, the region R having a heat transport amount of 95 to 100% indicated by a broken line in FIG. 2) is reached. Therefore, excessive cooling of the vicinity of the tip 1b1 is reduced when the power is below the maximum power (that is, when the other Peltier element units 4a to 4c reach the maximum heat absorption amount). That is, even when the amount of heat absorbed on the cooling side by the plurality of Peltier element units 4a to 4d approaches the maximum heat transport amount of the heat pipe 1, the cooling-side tip 1b1 in the internal flow path 1b of the heat pipe 1 is excessive. Cooling is reduced. Thereby, the phenomenon that the working fluid is retained at the cooling-side tip portion 1b1 in the internal flow path 1b of the heat pipe 1 is suppressed, and the circulation of the working fluid can be reduced.

  Therefore, by driving each Peltier element unit in a state where there is no stagnation of the hydraulic fluid, the steam in the internal flow path 1b of the heat pipe 1 is spread over the other end side 1a2 of the outer wall 1a corresponding to the cooling units 3a to 3d. Since a portion that is evenly distributed and excessively cooled does not easily occur, the working fluid is easily refluxed to cool the heat source 2. Thereby, the temperature difference of the front and back of a Peltier device unit decreases, and the power efficiency of a Peltier device unit is improved. As a result, the limit of the heat transport amount of the cooling device is increased as compared with the comparative example, and the power efficiency is also improved.

  Note that the control shown in FIG. 2 is an example, and the relationship between the heat transport amount and the heat absorption amount of the Peltier element may be configured by an arbitrary curve, and the heat transport amount at which each Peltier element unit starts operating is also free. Can be determined.

Embodiment 2. FIG.
Next, the cooling device 200 according to the second embodiment will be described with reference to FIG. FIG. 3 is a perspective view illustrating a part of the configuration of the cooling device 200 according to the second embodiment. Below, it demonstrates focusing on a different point from Embodiment 1. FIG.

  The cooling device 200 includes a plurality of heat pipes 201-1 to 201-3 and a cooling unit block 203. A plurality of heat pipes 201-1 to 201-3 are arranged side by side (for example, parallel to each other). Each of the heat pipes 201-1 to 201-3 extends so as to penetrate the inside of the cooling unit block 203. That is, the cooling unit block 203 is connected so as to surround the outer wall of each heat pipe 201-1 to 201-3 when viewed in a cross section perpendicular to the longitudinal direction of each heat pipe 201-1 to 201-3. Yes.

  In the second embodiment, the heat transport amount can be increased by increasing the number of heat pipes, and the heat flow can be distributed to the cooling surface and the heat source of the Peltier element unit to improve the cooling efficiency.

Embodiment 3 FIG.
Next, the cooling device 300 according to the third embodiment will be described with reference to FIG. FIG. 4 is a diagram illustrating a configuration of the cooling device 300 according to the third embodiment. Below, it demonstrates focusing on a different point from Embodiment 1. FIG.

  The cooling device 300 includes a cooling unit block (cooling block) 303, a plurality of Peltier element units 304a to 304d, a heat radiation unit block 305, and a control device 307. The two cooling blocks 3 and 303 are arranged so as to sandwich the heat pipe 1. The plurality of Peltier element units 4 a to 4 d and 304 a to 304 d are arranged so as to sandwich the two cooling blocks 3 and 303 and the heat pipe 1.

  The heat dissipating unit block 305 extends along the longitudinal direction of the heat pipe 1. A plurality of Peltier element units 304 a to 304 d are connected to one main surface of the heat radiating unit block 305.

  The control device 307 is connected to a plurality of Peltier element units 304a to 304d via a plurality of control lines 306a to 306d. The control device 307 drives each Peltier element unit 304a to 304d by supplying electric power to the corresponding Peltier element unit 304a to 304d via each control line 306a to 306d.

  Specifically, the control device 307 closes the plurality of Peltier element units 4a to 4d and 304a to 304d to the heat source 2 in accordance with the amount of heat transport from the heat source 2 side of the heat pipe 1 to the cooling blocks 3 and 303 side. The driving of the plurality of Peltier element units 4a to 4d, 304a to 304d is controlled so as to start driving sequentially with priority from the side. Further, the control device 307 gives priority to the plurality of Peltier element units 4a to 4d and 304a to 304d from the side far from the heat source 2 according to the amount of heat transport from the heat source 2 side of the heat pipe 1 to the cooling blocks 3 and 303 side. Then, the driving of the plurality of Peltier element units 4a to 4d and 304a to 304d is controlled so as to finish driving sequentially.

  In Embodiment 3, since the number of Peltier element units can be increased with respect to the unit length of the heat pipe 1, the heat transport amount of the heat pipe 1 can be easily increased.

Embodiment 4 FIG.
Next, the cooling device 400 according to the fourth embodiment will be described with reference to FIG. FIG. 5 is a diagram illustrating a configuration of the cooling device 400 according to the fourth embodiment. Below, it demonstrates focusing on a different point from Embodiment 1. FIG.

  The cooling device 400 includes a plurality of Peltier element units 404 a to 404 d and a control device 407. Each of the plurality of Peltier element units 404a to 404d has a plurality of cooling circuits. For example, the Peltier element unit 404a includes a plurality of cooling circuits 404a1 to 404a4. The control device 407 individually drives a plurality of cooling circuits in each of the plurality of Peltier element units 404a to 404d. For example, the control device 407 is connected to a plurality of cooling circuits 404a1 to 404a4 via a plurality of control lines 406a1 to 406a4. As a result, the control device 407 individually drives the plurality of cooling circuits 404a1 to 404a4 in the Peltier element unit 404a. Each cooling circuit is, for example, one in which a P-type semiconductor and an N-type semiconductor are alternately electrically connected in series.

  In the fourth embodiment, since a plurality of cooling circuits in each Peltier element unit are individually driven, it is easy to partially cool an arbitrary position in the Peltier element unit. Further, since one Peltier element unit is disassembled and controlled at a plurality of positions, the cooling region can be subdivided and controlled. That is, it becomes possible to control the cooling region corresponding to the position of the cooling circuit with a degree of freedom greater than the number of Peltier element units.

Embodiment 5 FIG.
Next, a cooling device 500 according to the fifth embodiment will be described with reference to FIG. FIG. 6 is a diagram illustrating a configuration of a cooling device 500 according to the fifth embodiment. Below, it demonstrates focusing on a different point from Embodiment 1. FIG.

  The cooling device 500 includes a temperature sensor 511 and a control device 507. The temperature sensor 511 includes a plurality of detection terminals (a plurality of detection units) 511a to 511d that detect the temperatures of the heat absorbing surfaces of the plurality of Peltier element units 4a to 4d. Each detection terminal 511a-511d detects the temperature of the heat absorption surface of corresponding Peltier device unit 4a-4d by detecting the temperature of corresponding cooling part 3a-3d, for example. The temperature sensor 511 supplies information on the temperatures detected by the detection terminals 511a to 511d to the control device 507.

  Based on the temperature detected by the detection terminals 511a to 511d of the temperature sensor 511, the control device 507 suppresses cooling of the Peltier element unit whose temperature is lower than that of other Peltier element units. That is, the control device 507 determines whether or not there is a temperature equal to or lower than a threshold value among the temperatures detected by the detection terminals 511a to 511d. The control device 507 corresponds to the detection terminal that detects the temperature below the threshold among the plurality of Peltier element units 4a to 4d when there is a temperature below the threshold, that is, when any of the detection terminals detects a temperature below the threshold. The driving of the Peltier element unit is suppressed as compared with the driving of other Peltier element units. Thereby, it is suppressed that a hydraulic fluid condenses excessively in the part by which the cooling in the internal flow path 1b of the heat pipe 1 was suppressed.

  In the fifth embodiment, it is possible to control the temperature of each cooling unit 3a to 3d of the heat pipe 1 to stop the cooling of the portion where the liquid pool has occurred in the internal flow path 1b of the heat pipe 1. By controlling in this way, optimal vapor condensation is maintained in the whole cooling part in the internal flow path 1b of the heat pipe 1, and the maximum heat transport capability of the heat pipe 1 is improved.

Embodiment 6 FIG.
Next, a cooling device 600 according to the sixth embodiment will be described with reference to FIG. FIG. 7 is a diagram illustrating a configuration of a cooling device 600 according to the sixth embodiment. Below, it demonstrates focusing on a different point from Embodiment 1. FIG.

  The cooling device 600 includes an electromotive force measurement device 612, a control device 607, and a temperature sensor 609. When the operation of the plurality of Peltier element units 4a to 4d is instantaneously stopped after the heat pipe 1 is cooled for a certain time by the plurality of Peltier element units 4a to 4d, each Peltier element unit 4a to 4d In the absence of power supply (voltage application), an electromotive force is generated according to the temperature difference between the front and back sides. The electromotive force measuring device 612 measures this electromotive force. That is, the electromotive force measuring device 612 has a plurality of detection nodes (detection nodes) that detect electromotive forces in the plurality of Peltier element units 4a to 4d when the control device 607 simultaneously stops driving the plurality of Peltier element units 4a to 4d. A plurality of second detection units) 612a to 612d. Each of the detection nodes 612a to 612d detects the electromotive force in the corresponding Peltier element unit 4a to 4d, for example, by detecting the voltage of the corresponding control line 6a to 6d. The electromotive force measurement device 612 supplies information on the electromotive force detected by the detection nodes 612a to 612d to the control device 607. The temperature sensor 609 measures the temperature of the heat source 2.

  The control device 607 sets the output to the Peltier element according to the difference between the temperature of the heat source 2 measured by the temperature sensor 609 and the target temperature. Furthermore, the control device 607 calculates the temperature difference between the front and back surfaces (the heat absorption surface and the heat dissipation surface) of the plurality of Peltier element units 4a to 4d from the electromotive forces detected by the plurality of detection nodes 612a to 612d of the electromotive force measurement device 612. Estimate. The control device 607 determines the driving power (driving voltage) of each Peltier element unit at the time of restarting cooling based on the estimated value. That is, the control device 607 determines whether there is a temperature difference equal to or greater than a threshold value among the temperature differences estimated from the electromotive forces detected by the detection nodes 612a to 612d. The plurality of Peltier element units 4a to 4d are in contact with the common heat dissipation block 5, and the temperatures of the heat dissipation surfaces of the Peltier element units 4a to 4d are substantially the same. Therefore, in the Peltier element unit in which the temperature difference between the heat absorbing surface and the heat radiating surface is estimated to be equal to or greater than the threshold value, it is considered that the temperature of the heat absorbing surface is lowered below a predetermined lower limit. When the temperature difference equal to or greater than the threshold is estimated, the control device 607 compares the driving of the Peltier element unit in which the temperature difference equal to or greater than the threshold is estimated among the plurality of Peltier element units 4a to 4d as compared with the driving of other Peltier element units. To suppress. Thereby, it is suppressed that a hydraulic fluid condenses excessively in the part by which the cooling in the internal flow path 1b of the heat pipe 1 was suppressed.

  In the sixth embodiment, the temperature sensor 511 (see FIG. 6) is not used, that is, the temperature measurement sensor and its wiring in the vicinity of the Peltier element unit are omitted, and the temperatures of the cooling units 3a to 3d of the heat pipe 1 are omitted. It is possible to control such that the cooling of the portion where the liquid pool has occurred in the internal flow path 1b of the heat pipe 1 is stopped. By controlling in this way, the optimum vapor condensation is maintained in the whole cooling part in the internal flow path 1b of the heat pipe 1, and the maximum heat transport capacity of the heat pipe 1 is improved.

Embodiment 7 FIG.
Next, as Embodiment 7, an example in which the cooling device according to Embodiments 1 to 6 is applied to an image display device will be described with reference to FIG. FIG. 8 shows an example in which the cooling device 200 according to the second embodiment is used for cooling the laser element of the image display device 700 as an example.

  The image display device 700 includes a laser element 714, an image projection device 715, a screen 716, and a cooling device 200. In the image display device 700, the light emitted from the laser element 714 is projected as an image on the screen 716 through an image modulation device (not shown) and an optical device (not shown) in the image projection device 715. A projected image (for example, a moving image) is displayed on the screen 716. As the laser element 714, for example, a semiconductor laser element is used. A cooling device serving as a heat source is attached to these semiconductor laser elements. For example, a plurality of laser elements 714 (714r, 714g, 714b) are arranged for the purpose of color display.

  In the cooling device 200, when the current temperature (in the vicinity of the cooling unit 3a and / or in the vicinity of the heat source 2) is significantly higher than the target temperature, the capability (drive power) is increased, and the capability (drive power) is increased as the target temperature is approached. ) Is controlled to lower. The adjustment amount of this control is determined by the control device 7 (see FIG. 1).

  In the seventh embodiment, the maximum heat transport capability of the cooling device 200 is improved by using any of the configurations of the first to sixth embodiments for the cooling device 200. When it is necessary to dispose the drive circuit in the vicinity of the laser element 714, the degree of freedom in design is improved by connecting the cooling device 200 with increased heat transport capability of the heat pipe to the laser element 714. Further, the power efficiency of the Peltier element unit is improved, and the power consumption of the entire image display device 700 can be reduced.

  Although the illustration of the temperature sensor is omitted in FIG. 8, various types of arrangement of the temperature sensor or the electromotive force detection circuit of the sixth embodiment may be selected in accordance with the design of the image display device. A plurality of heat pipes may be used as in the second embodiment. Further, in order to increase the efficiency of heat dissipation, heat dissipation fins 713 are connected to the main surface opposite to one main surface to which the plurality of Peltier element units 4a to 4d are connected in the heat dissipation unit block 5. Also good.

Embodiment 8 FIG.
Next, as an eighth embodiment, another example in which the cooling device according to the first to sixth embodiments is applied to an image display device will be described with reference to FIG. Below, it demonstrates focusing on a different point from Embodiment 7. FIG.

  In the image display apparatus 700 of FIG. 8, the laser elements 714r, 714g, and 714b of a plurality of colors are dynamically controlled according to the color balance of an image (for example, a moving image) whose output is projected, thereby improving the display image. May have a function to do. In other words, the laser control unit (not shown) can display an image having an appropriate color balance according to the color balance of an image projected on the screen (display screen) 716 by the laser elements 714r, 714g, and 714b of the plurality of colors. As displayed on the screen 716, the outputs of the laser elements 714r, 714g, and 714b of a plurality of colors are dynamically controlled. At this time, in the image display device 700, the amount of heat generated by the laser elements 714r, 714g, and 714b of the plurality of colors changes according to the operation state.

  In the eighth embodiment, the number of heat pipes is equal to the number of Peltier elements by using the configuration of any of the first to sixth embodiments for cooling the laser elements 714r, 714g, and 714b of a plurality of colors. Compared to the case, the maximum output control range of the laser element can be made wider. In addition, even when the output changes from a low state to a high state, the temperature of the cooling part of the heat pipe is kept uniform. The power consumption of the apparatus can be reduced.

  As described above, the cooling device and the image display device according to the present invention are useful for a device that performs cooling using a plurality of Peltier elements.

1, 201-1 to 201-3 Heat pipe 2 Heat source 3, 203, 303 Cooling block 4a to 4d, 304a to 304d, 404a to 404d Peltier element unit 5, 305 Radiating block 6a to 6d, 306a to 306d, 406a1 -406a4 Control line 7,307,407,507,607 Control device 8 Temperature sensor 9 Temperature sensor 404a1-404a4 Cooling circuit 511 Temperature sensor 511a-511d Detection terminal 612 Electromotive force measurement device 612a-612d Detection node 713 Radiation fin 714, 714r , 714g, 714b Laser element 715 Image projector 716 Screen

Claims (8)

A cooling block;
A heat pipe in which hydraulic fluid is enclosed, one end of the outer wall is connected to a heat source, and the other end of the outer wall is connected to the cooling block;
A plurality of Peltier element units arranged along the longitudinal direction of the heat pipe so as to cool the heat pipe via the cooling block;
Control driving of the plurality of Peltier element units so as to sequentially drive the plurality of Peltier element units from the side close to the heat source in accordance with the amount of heat transport from the heat source side to the cooling block side of the heat pipe. A control unit,
A cooling device comprising: The cooling device according to claim 1, wherein a plurality of the heat pipes are provided. Two cooling blocks,
The two cooling blocks are arranged so as to sandwich the heat pipe,
The cooling device according to claim 1, wherein the plurality of Peltier element units are arranged so as to sandwich the two cooling blocks and the heat pipe. Each of the plurality of Peltier element units has a plurality of cooling circuits,
The cooling device according to claim 1, wherein the control unit individually drives the plurality of cooling circuits in each of the plurality of Peltier element units. A plurality of detectors for detecting the temperature of the endothermic surfaces of the plurality of Peltier element units,
When the temperature below the threshold is detected by the detector, the controller controls driving of the Peltier element unit corresponding to the detector that detected the temperature below the threshold among the plurality of Peltier element units. The cooling device according to claim 1, wherein the cooling device is suppressed as compared with driving of the element unit. A plurality of second detection units for detecting electromotive forces in the plurality of Peltier element units when driving of the plurality of Peltier element units is simultaneously stopped by the control unit;
The control unit estimates the temperature difference between the heat absorption surface and the heat dissipation surface of the plurality of Peltier element units from the electromotive force in the plurality of Peltier element units detected by the plurality of second detection units, and estimates the temperature When the difference is less than or equal to a threshold value, driving of the Peltier element unit in which a temperature difference equal to or greater than the threshold value is estimated among the plurality of Peltier element units is suppressed as compared with driving of other Peltier element units. Item 2. The cooling device according to Item 1. A laser element;
The cooling device according to any one of claims 1 to 6, wherein the laser element is cooled;
An image display device comprising: Multiple color laser elements;
A laser control unit for dynamically controlling the output of each of the laser elements of the plurality of colors according to the color balance of the image projected on the display screen by the laser elements of the plurality of colors;
The cooling device according to any one of claims 1 to 6, which cools the laser elements of the plurality of colors.
An image display device comprising:

Images