JP2021081156A - Cooling device and projector - Google Patents

Abstract

To provide a cooling device and a projector each enabling their cooling efficiency to be improved.SOLUTION: A cooling device comprises: an evaporation unit changing a working fluid from a liquid phase to a gas phase by heat of a cooled object; a condensation unit changing the working fluid from the gas phase to the liquid phase; a steam pipe flowing the working fluid of gas phase to the condensation unit; and a liquid pipe flowing the working fluid of liquid phase to the evaporation unit. The evaporation unit comprises: a housing having a reservoir into which the working fluid of liquid phase flows from the liquid pipe; a wick disposed in the housing and conveying the working fluid of liquid phase; and a groove member to which heat of the cooled object is transmitted. The groove member has a base portion, a plurality of projecting portions projecting from the base portion and connected to the wick, and a plurality of flow channels surrounded by the base portion, the plurality of projecting portion, and the wick. The wick has a first portion to which the working fluid of liquid phase is supplied from the reservoir, and a second portion to which the working fluid of liquid phase is conveyed from the first portion, and which is connected to the base portion and the plurality of projecting portions. The base portion has a plurality of recessed portions at positions opposed to the second portion.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to cooling devices and projectors.

Conventionally, as a cooling device used for cooling an electronic device or the like, a loop type heat pipe that cools a heating element by transporting the heat of the heating element by utilizing the phase change of the working fluid enclosed inside is known. (See, for example, Patent Document 1).
The loop type heat pipe described in Patent Document 1 includes an evaporation unit, a condensing unit, a vapor pipe, and a liquid pipe. The evaporating part evaporates the working fluid of the liquid phase by the heat of the heating element. In the vapor pipe, the working fluid changed from the liquid phase to the gas phase in the evaporation part is circulated to the condensing part. The condensing part condenses the working fluid of the gas phase by heat dissipation and changes it into the working fluid of the liquid phase. The liquid pipe circulates the working fluid changed to the liquid phase in the condensing part to the evaporation part.
In this way, the working fluid circulates in the loop type heat pipe, and the heat of the heating element is transported from the evaporation part to the condensing part and released at the condensing part to cool the heating element.

In the loop type heat pipe described in Patent Document 1, the evaporation portion accommodates a flat plate type wick, a plurality of grooves arranged under the wick to form a steam flow path, and a wick and a plurality of grooves. The heating element is connected to the housing.
The wick is made of a porous material. A large number of pores are provided inside the wick, and the large number of pores communicate with each other from the liquid reservoir side to the vapor flow path side. The working fluid of the liquid phase infiltrates a large number of pores from the liquid reservoir in the housing by capillarity. The liquid phase working fluid that has penetrated into a large number of pores evaporates due to the heat transferred from the heating element and changes to the vapor phase working fluid, and the vapor phase working fluid is partitioned by multiple grooves. It circulates in the steam flow path and circulates in the steam pipe.

Japanese Unexamined Patent Publication No. 2012-83082

In order to increase the cooling efficiency of the cooling target by the loop type heat pipe, it is conceivable to increase the heat transfer efficiency transferred from the cooling target. Then, in order to increase the transfer efficiency, it is conceivable to expand the area of the evaporation site where the working fluid of the liquid phase is evaporated by the heat transferred from the cooling target.
However, in the loop type heat pipe described in Patent Document 1, the evaporation site of the working fluid of the liquid phase is mainly the end portion in contact with the wick in a plurality of grooves. Therefore, there is a problem that the area of the evaporation portion is not necessarily large and it is difficult to increase the cooling efficiency of the cooling target.

The cooling device according to the first aspect of the present disclosure includes an evaporating unit that evaporates the working fluid of the liquid phase by heat transferred from the object to be cooled and changes the working fluid of the liquid phase into the working fluid of the gas phase. The condensed part that condenses the working fluid in the gas phase and changes the working fluid in the gas phase into the working fluid in the liquid phase, and the condensed working fluid that changes from the liquid phase to the gas phase in the evaporation part. A steam pipe for flowing to the unit and a liquid pipe for flowing the working fluid changed from the gas phase to the liquid phase in the condensing part to the evaporating part are provided, and the evaporating part is connected to the liquid pipe. A housing having a reservoir for storing the working fluid of the liquid phase that has flowed into the inside, and a wick provided in the housing in which the working fluid of the liquid phase permeates and transports the working fluid of the liquid phase. The groove member comprises a groove member connected to the wick and to which heat to be cooled is transferred, and the groove member includes a base portion, a plurality of convex portions projecting from the base portion and connected to the wick, and the groove member. It has a base, a plurality of protrusions, and a plurality of flow paths through which the working fluid changed from a liquid phase to a gas phase flows, which is surrounded by the wick, and the wick is the operation of the liquid phase from the reservoir. The base has a first portion to which the fluid is supplied and a second portion to which the working fluid of the liquid phase is transported from the first portion and is connected to the base portion and the plurality of convex portions. It is characterized by having a plurality of recesses at positions facing the second portion.

The projector according to the second aspect of the present disclosure includes a light source that emits light, an optical modulator that modulates the light emitted from the light source, and a projection optical apparatus that projects light modulated by the optical modulator. It is characterized by including the above-mentioned cooling device.

The perspective view which shows the appearance of the projector in 1st Embodiment. The schematic diagram which shows the internal structure of the projector in 1st Embodiment. The schematic diagram which shows the structure of the light source apparatus in 1st Embodiment. The perspective view which shows the appearance of the evaporation part in 1st Embodiment. The cross-sectional view which shows typically the internal structure of the evaporation part in 1st Embodiment. The cross-sectional view which shows typically the internal structure of the evaporation part in 1st Embodiment. FIG. 5 is an enlarged cross-sectional view showing a part of the heat exchange portion in the first embodiment. FIG. 6 is an enlarged view showing a part of the groove member in the first embodiment. The figure which enlarged and shows a part of the groove member which is the deformation of the groove member in 1st Embodiment. The figure which enlarges and shows a part of the groove member which the cooling device included in the projector in 2nd Embodiment has.

[First Embodiment]
Hereinafter, the first embodiment of the present disclosure will be described with reference to the drawings.
[Outline configuration of projector]
FIG. 1 is a perspective view showing the appearance of the projector 1 according to the present embodiment.
The projector 1 according to the present embodiment is an image display that modulates the light emitted from the light source 411, which will be described later, to form an image according to the image information, and magnifies and projects the formed image on a projected surface such as a screen. It is a device. As shown in FIG. 1, the projector 1 includes an exterior housing 2 that constitutes the exterior of the projector 1.

[Outer housing configuration]
The exterior housing 2 has a top surface portion 21, a bottom surface portion 22, a front surface portion 23, a back surface portion 24, a left side surface portion 25, and a right side surface portion 26, and is formed in a substantially rectangular parallelepiped shape.
The bottom surface portion 22 has a plurality of leg portions 221 in contact with the installation surface on which the projector 1 is placed.
The front portion 23 is located on the projection side of the image in the exterior housing 2. The front portion 23 has an opening 231 that exposes a part of the projection optical device 36 described later, and the image projected by the projection optical device 36 passes through the opening 231. Further, the front portion 23 has an exhaust port 232 in which the cooling gas that has cooled the object to be cooled in the projector 1 is discharged to the outside of the outer housing 2.
The right side surface portion 26 has an introduction port 261 that introduces a gas such as air outside the outer housing 2 into the inside as a cooling gas.

[Internal configuration of projector]
FIG. 2 is a schematic view showing the internal configuration of the projector 1.
As shown in FIG. 2, the projector 1 includes an image projection device 3 and a cooling device 5 inside the outer housing 2. In addition, although not shown, the projector 1 includes a control device for controlling the operation of the projector 1 and a power supply device for supplying electric power to electronic components of the projector 1.

[Configuration of image projection device]
The image projection device 3 forms an image according to the image information input from the control device, and projects the formed image. The image projection device 3 includes a light source device 4, a homogenization device 31, a color separation device 32, a relay device 33, an image forming device 34, an optical component housing 35, and a projection optical device 36.
The light source device 4 emits illumination light. The configuration of the light source device 4 will be described in detail later.

The homogenizing device 31 homogenizes the illumination light emitted from the light source device 4. The homogenized illumination light passes through the color separation device 32 and the relay device 33, and illuminates the modulation region of the light modulation device 343 described later in the image forming device 34. The homogenizing device 31 includes two lens arrays 311, 312, a polarization conversion element 313, and a superimposing lens 314.
The color separating device 32 separates the light incident from the homogenizing device 31 into red, green, and blue color lights. The color separator 32 includes two dichroic mirrors 321 and 322 and a reflection mirror 323 that reflects blue light separated by the dichroic mirror 321.

The relay device 33 is provided in an optical path of red light that is longer than the optical path of other colored light, and suppresses the loss of red light. The relay device 33 includes an incident side lens 331, a relay lens 333, and reflection mirrors 332 and 334. In the present embodiment, the colored light having a longer optical path than the other colored lights is regarded as red light, and the relay device 33 is provided on the optical path of the red light. However, the present invention is not limited to this, and for example, a colored light having a longer optical path than other colored lights may be defined as blue light, and a relay device 33 may be provided on the optical path of the blue light.

The image forming apparatus 34 modulates each of the incident red, green, and blue color lights, and synthesizes each of the modulated color lights. The image forming apparatus 34 includes three field lenses 341, three incident side polarizing plates 342, three optical modulation devices 343, three viewing angle compensating plates 344, three emitting side polarizing plates 345, and one color synthesizer 346. And. The set of the field lens 341, the incident side polarizing plate 342, the optical modulation device 343, the viewing angle compensating plate 344, and the emitting side polarizing plate 345 is provided according to the incident colored light.
The light modulation device 343 modulates the light emitted from the light source device 4 according to the image information. The optical modulator 343 includes an optical modulator 343R for red light, an optical modulator 343G for green light, and an optical modulator 343B for blue light. In the present embodiment, the light modulation device 343 is composed of a transmissive liquid crystal panel, and the liquid crystal light valve is composed of the incident side polarizing plate 342, the light modulation device 343, and the outgoing side polarizing plate 345.
The color synthesizer 346 synthesizes each color light modulated by the light modulators 343B, 343G, and 343R. In the present embodiment, the color synthesizer 346 is composed of a cross dichroic prism, but the present invention is not limited to this, and for example, it can be configured by a plurality of dichroic mirrors.

The housing 35 for optical components houses the above-mentioned devices 31 to 34 inside. The image projection device 3 is set with an illumination optical axis Ax, which is a design optical axis, and the housing 35 for optical components holds each device 31 to 34 at a predetermined position on the illumination optical axis Ax. .. The light source device 4 and the projection optical device 36 are arranged at predetermined positions on the illumination optical axis Ax.
The projection optical device 36 magnifies and projects the image incident from the image forming device 34 onto the projected surface. That is, the projection optical device 36 projects the light modulated by the light modulation devices 343B, 343G, 343R. The projection optical device 36 is configured as, for example, a group lens in which a plurality of lenses are housed in a tubular lens barrel.

[Configuration of light source device]
FIG. 3 is a schematic view showing the configuration of the light source device 4.
The light source device 4 emits the illumination light to the homogenizing device 31. As shown in FIG. 3, the light source device 4 includes a light source housing CA, a light source unit 41 housed in the light source housing CA, an afocal optical element 42, a homogenizer optical element 43, and a polarization separating element 44. It includes a first light source element 45, a wavelength conversion element 46, a first phase difference element 47, a second light source element 48, a diffuse reflection device 49, and a second phase difference element RP.
The light source housing CA is configured as a closed housing in which dust and the like do not easily enter the inside.

The light source unit 41, the afocal optical element 42, the homogenizer optical element 43, the polarization separating element 44, the first retardation element 47, the second condensing element 48, and the diffuse reflection device 49 are illuminated optical axes set in the light source device 4. It is arranged on Ax1.
The wavelength conversion element 46, the first condensing element 45, the polarization separating element 44, and the second retardation element RP are set in the light source device 4 and arranged on the illumination optical axis Ax2 orthogonal to the illumination optical axis Ax1. There is. The illumination optical axis Ax2 coincides with the illumination optical axis Ax at the position of the lens array 311. In other words, the illumination optical axis Ax2 is set on an extension of the illumination optical axis Ax.

[Structure of light source unit]
The light source unit 41 includes a light source 411 that emits light and a collimator lens 415.
The light source 411 includes a plurality of first semiconductor lasers 412, a plurality of second semiconductor lasers 413, and a support member 414.
The plurality of first semiconductor lasers 412 are arranged in an array on a plane orthogonal to the illumination optical axis Ax1. The first semiconductor laser 412 is an LD (Laser Diode) that emits s-polarized blue light L1s as excitation light to the polarization separating element 44. The blue light L1s is, for example, laser light having a peak wavelength of 440 nm. The blue light L1s emitted from the first semiconductor laser 412 is incident on the wavelength conversion element 46.
The plurality of second semiconductor lasers 413 are arranged in an array on a plane orthogonal to the illumination optical axis Ax1. The second semiconductor laser 413 is an LD (Laser Diode) that emits p-polarized blue light L2p to the polarization separating element 44. The blue light L2p is, for example, laser light having a peak wavelength of 460 nm. The blue light L2p emitted from the second semiconductor laser 413 is incident on the diffuse reflector 49.
In the light source device 4, the s-polarized light indicates light that is s-polarized with respect to the polarization separating element 44, and the p-polarized light indicates light that is p-polarized with respect to the polarizing separation element 44. ..

The support member 414 supports a plurality of first semiconductor lasers 412 and a plurality of second semiconductor lasers 413. The support member 414 is a metal member having thermal conductivity, and is connected to an evaporation unit 6 described later. Then, the heat of the semiconductor lasers 421 and 413, which are the heat sources, that is, the heat of the light source 411 is transferred to the evaporation unit 6.

The blue light L1s emitted from the first semiconductor laser 412 and the blue light L2p emitted from the second semiconductor laser 413 are converted into parallel light beams by the collimator lens 415 and incident on the afocal optical element 42.
In the present embodiment, the light source 411 is configured to emit s-polarized blue light L1s and p-polarized blue light L2p. However, the present invention is not limited to this, and the light source 411 may be configured to emit blue light which is linearly polarized light having the same polarization direction. In this case, a phase difference element that converts one type of incident linearly polarized light into light including s-polarized light and p-polarized light may be arranged between the light source unit 41 and the polarization separating element 44.

[Structure of afocal optical element and homogenizer optical element]
The afocal optical element 42 adjusts the luminous flux diameters of the blue light L1s and L2p incident from the light source unit 41 so that the blue light L1s and L2p are incident on the homogenizer optical element 43. The afocal optical element 42 is composed of a lens 421 that collects incident light and a lens 422 that parallelizes the light flux collected by the lens 421.
The homogenizer optical element 43 equalizes the illuminance distribution of blue light L1s and L2p. The homogenizer optical element 43 is composed of a pair of multi-lens arrays 431 and 432.

[Structure of polarization separation element]
The blue light L1s and L2p that have passed through the homogenizer optical element 43 are incident on the polarization separating element 44.
The polarization separation element 44 is a prism-type polarization beam splitter, which separates the s-polarization component and the p-polarization component contained in the incident light. Specifically, the polarization separating element 44 reflects the s polarization component and transmits the p polarization component. Further, the polarization separating element 44 has a color separation characteristic of transmitting light having a predetermined wavelength or more regardless of the polarization component of the s polarization component and the p polarization component. Therefore, the s-polarized blue light L1s is reflected by the polarization separating element 44 and is incident on the first condensing element 45. On the other hand, the p-polarized blue light L2p passes through the polarization separating element 44 and is incident on the first retardation element 47.

[Structure of the first condensing element]
The first condensing element 45 condenses the blue light L1s reflected by the polarization separating element 44 on the wavelength conversion element 46. Further, the first condensing element 45 parallelizes the fluorescence YL incident from the wavelength conversion element 46. In the example of FIG. 3, the first condensing element 45 is composed of two lenses 451 and 452, but the number of lenses constituting the first condensing element 45 does not matter.

[Structure of wavelength conversion element]
The wavelength conversion element 46 is excited by the incident light and emits a fluorescent YL having a wavelength longer than that of the incident light. In other words, the wavelength conversion element 46 converts the wavelength of the incident light and emits the converted light. The fluorescent YL generated by the wavelength conversion element 46 is, for example, light having a peak wavelength of 500 to 700 nm. The wavelength conversion element 46 includes a wavelength conversion unit 461 and a heat dissipation unit 462.
Although not shown, the wavelength conversion unit 461 has a wavelength conversion layer and a reflection layer. The wavelength conversion layer includes a phosphor that diffuses and emits fluorescent YL, which is unpolarized light obtained by wavelength-converting the incident blue light L1s. The reflective layer reflects the fluorescent YL incident from the wavelength conversion layer toward the first condensing element 45.
The heat radiating unit 462 is provided on the surface of the wavelength conversion unit 461 opposite to the light incident side, and releases the heat generated by the wavelength conversion unit 461.

The fluorescent YL emitted from the wavelength conversion element 46 passes through the first condensing element 45 along the illumination optical axis Ax2, and then is incident on the polarization separation element 44 having the color separation characteristic. The fluorescent YL passes through the polarization separating element 44 along the illumination optical axis Ax2 and is incident on the second retardation element RP.
The wavelength conversion element 46 may be configured to be rotated about a rotation axis parallel to the illumination optical axis Ax2 by a rotating device such as a motor.

[Structure of 1st phase difference element and 2nd condensing element]
The first retardation element 47 is arranged between the polarization separating element 44 and the second condensing element 48. The first retardation element 47 converts the blue light L2p that has passed through the polarization separating element 44 into circularly polarized blue light L2c. The blue light L2c is incident on the second condensing element 48.
The second condensing element 48 condenses the blue light L2c incident from the first retardation element 47 on the diffuse reflector 49. Further, the second condensing element 48 parallelizes the blue light L2c incident from the diffuse reflection device 49. The number of lenses constituting the second condensing element 48 can be changed as appropriate.

[Diffuse reflector configuration]
The diffuse reflector 49 diffusely reflects the incident blue light L2c at a diffusion angle similar to that of the fluorescence YL emitted from the wavelength conversion element 46. As a configuration of the diffuse reflector 49, a configuration including a reflector for Lambertian reflecting the incident blue light L2c and a rotating device for rotating the reflector about a rotating axis parallel to the illumination optical axis Ax1 can be exemplified.
The blue light L2c diffusely reflected by the diffuse reflector 49 passes through the second condensing element 48 and then is incident on the first retardation element 47. When the blue light L2c is reflected by the diffuse reflector 49, it is converted into circularly polarized light whose rotation direction is opposite. Therefore, the blue light L2c incident on the first retardation element 47 via the second condensing element 48 is the p-polarized blue light L2p when it is incident on the first retardation element 47 from the polarization separation element 44. Instead, it is converted into s-polarized blue light L2s. Then, the blue light L2s is reflected by the polarization separating element 44 and incident on the second retardation element RP. That is, the light incident on the second retardation element RP from the polarization separating element 44 is white light in which blue light L2s and fluorescent YL are mixed.

[Structure of second phase difference element]
The second retardation element RP converts the white light incident from the polarization separating element 44 into light in which s-polarized light and p-polarized light are mixed. The white illumination light WL thus converted is incident on the homogenizing device 31 described above.

[Cooling device configuration]
The cooling device 5 cools the cooling target constituting the projector 1. In the present embodiment, the cooling target is the light source 411 of the light source device 4. As shown in FIG. 2, the cooling device 5 includes a loop type heat pipe 51 and a cooling fan 55.
The cooling fan 55 is provided between the exhaust port 232 and the condensing portion 53 of the loop type heat pipe 51, which will be described later, in the space inside the exterior housing 2. The cooling fan 55 circulates the cooling gas through the condensing portion 53 in the process of sucking the cooling gas in the outer housing 2 and discharging the cooling gas from the exhaust port 232, thereby cooling the condensing portion 53. The cooling fan 55 is provided between the introduction port 261 and the condensing portion 53 in the space inside the exterior housing 2, for example, and sucks the cooling gas outside the exterior housing 2 to supply the cooling gas to the condensing portion 53. It may be configured to send.

The loop type heat pipe 51 has a circulation flow path in which a working fluid whose phase state changes at a relatively low temperature circulates when it is sealed in a reduced pressure state. More specifically, the loop type heat pipe 51 changes the phase state of the working fluid from the liquid phase to the gas phase by the heat transferred from the object to be cooled, except for the portion where the working fluid undergoes a phase change from the liquid phase to the gas phase. The object to be cooled is cooled by releasing the heat of the working fluid of the gas phase at the site of. Further, the loop type heat pipe 51 changes the phase state of the working fluid from the gas phase to the liquid phase by taking heat from the working fluid of the gas phase, and the heat from the cooling target heats the working fluid changed to the liquid phase. Distribute to the part to be transmitted.
Such a loop type heat pipe 51 includes an evaporation unit 6, a vapor pipe 52, a condensing unit 53, and a liquid pipe 54. The configuration of the evaporation unit 6 will be described in detail later.

[Steam pipe configuration]
The steam pipe 52 is a tubular member that connects the evaporation section 6 and the condensing section 53 so that the working fluid of the gas phase can flow in the circulation flow path of the working fluid. The vapor pipe 52 circulates the working fluid that changes from the liquid phase to the gas phase in the evaporation unit 6 and flows in from the evaporation unit 6 to the condensing unit 53.

[Structure of condensing part]
The condensing unit 53 takes heat from the working fluid of the gas phase to cool the working fluid, causes the working fluid whose phase has changed from the gas phase to the liquid phase to flow out to the liquid pipe 54, and takes away from the working fluid of the gas phase. Dissipates heat. That is, the condensing unit 53 changes the working fluid of the gas phase into the working fluid of the liquid phase by condensing the working fluid of the gas phase. Although not shown, the condensing section 53 includes a main body section to which the vapor pipe 52 and the liquid tube 54 are connected, and a heat radiating section connected to the main body section.
The main body has a phase change flow path inside which the working fluid of the gas phase flowing in from the steam pipe 52 flows and communicates with the liquid pipe 54 as a part of the circulation flow path. The working fluid of the gas phase receives heat from the main body and is cooled in the process of flowing through the phase change flow path, whereby the working fluid of the liquid phase is changed. Then, the working fluid changed from the gas phase to the liquid phase further circulates in the phase change flow path, receives heat from the main body, is cooled, and then flows out to the liquid pipe 54.
The heat radiating portion is a member that releases the heat of the working fluid transmitted to the main body portion, and is a so-called heat sink. Cooling gas flows through the heat radiating section by driving the cooling fan 55, whereby the condensing section 53 is cooled.

[Construction of liquid tube]
The liquid pipe 54 is a tubular member that connects the condensing portion 53 and the evaporating portion 6 so that the working fluid of the liquid phase can flow in the circulation flow path of the working fluid. The liquid pipe 54 circulates the working fluid that has changed from the gas phase to the liquid phase in the condensing unit 53 to the evaporation unit 6.

[Structure of evaporation part]
The evaporation unit 6 is connected to the light source 411 as a cooling target, evaporates the working fluid of the liquid phase by the heat transferred from the light source 411, and changes the working fluid of the liquid phase into the working fluid of the gas phase. Specifically, the evaporation unit 6 is connected to the support member 414 of the light source 411 and evaporates the working fluid of the liquid phase by the heat of the semiconductor lasers 421 and 413 transmitted via the support member 414, whereby the semiconductor laser 412 , 413 are cooled.

FIG. 4 is a perspective view showing the appearance of the evaporation unit 6. 5 and 6 are cross-sectional views schematically showing the internal structure of the evaporation unit 6. Specifically, FIG. 5 is a diagram showing a cross section of the evaporation unit 6 including the virtual line VL1 shown by the dotted line in FIG. 4, and FIG. 6 is a diagram showing the evaporation unit including the virtual line VL2 shown by the alternate long and short dash line in FIG. It is a figure which shows the cross section of 6. That is, the cross section of the evaporation section 6 shown in FIG. 5 and the cross section of the evaporation section 6 shown in FIG. 6 are orthogonal to each other. In FIG. 5, in consideration of legibility, only a part of each of the plurality of sandwiching portions 652, the connecting portions 653, 654, the plurality of convex portions 662, and the plurality of flow paths 663 is coded. ..
The evaporation unit 6 includes a housing 61 as shown in FIGS. 4 to 6, and also includes a heat exchange unit 62 provided in the housing 61 as shown in FIGS. 5 and 6.

[Case configuration]
The housing 61 has a first housing 611 and a second housing 612 made of metal, respectively, and also has a sealing member 613 as shown in FIGS. 5 and 6. The housing 61 is formed in a substantially rectangular parallelepiped shape as a whole by combining the first housing 611 and the second housing 612 with the sealing member 613 provided inside. As shown in FIG. 4, the housing 61 has a top surface portion 61A, a bottom surface portion 61B, and side surface portions 61C, 61D, 61E, 61F.
The top surface portion 61A and the bottom surface portion 61B are portions of the housing 61 that are opposite to each other.
The side surface portion 61C and the side surface portion 61D are portions of the housing 61 that are opposite to each other. Further, the side surface portion 61E and the side surface portion 61F are portions of the housing 61 that are opposite to each other. That is, when the housing 61 is viewed so that the side surface portion 61C is the front portion of the housing 61, the top surface portion 61A is located on the upper side, and the bottom surface portion 61B is located on the lower side, the side surface portion 61D is the back surface portion of the housing 61. The side surface portion 61E is the left side surface portion of the housing 61, and the side surface portion 61F is the right side surface portion of the housing 61.

The bottom surface portion 61B is heat-transferredly connected to the light source 411, which is the cooling target of the loop type heat pipe 51. The heat of the light source 411 is transferred to the bottom surface portion 61B and thus to the second housing 612. A heat receiving member may be provided between the bottom surface portion 61B and the light source 411 to transfer the heat received from the light source 411 to the bottom surface portion 61B.

In the following description, the direction from the first housing 611 to the second housing 612 in the housing 61 is defined as the + Y direction. The two directions orthogonal to the + Y direction and orthogonal to each other are defined as the + X direction and the + Z direction. Although not shown, for convenience of explanation, the opposite direction of the + X direction is the −X direction, the opposite direction of the + Y direction is the −Y direction, and the opposite direction of the + Z direction is the −Z direction.

As shown in FIGS. 4 to 6, the first housing 611 constitutes a top surface portion 61A and a portion of the side surface portions 61C to 61F in the −Y direction. The internal space in the first housing 611 constitutes the reservoir 614 when combined with the second housing 612.
The first housing 611 has a liquid pipe connecting portion 6111 that protrudes in the + Z direction and is connected to the liquid pipe 54. The liquid pipe connecting portion 6111 communicates with the inside of the first housing 611. The working fluid of the liquid phase flowing through the liquid pipe 54 flows into the reservoir 614 via the liquid pipe connecting portion 6111.

The second housing 612 constitutes a bottom surface portion 61B and a portion of the side surface portions 61C to 61F in the + Y direction. Inside the second housing 612, a wick 63, which is a fluid transport layer of the heat exchange unit 62, and a groove member 66A, which is a flow path forming layer of the heat exchange unit 62, are provided. That is, a heat exchange portion 62 including a wick 63 and a groove member 66A is provided in the housing 61.
The second housing 612 has a steam pipe connecting portion 6121 that protrudes in the + X direction and is connected to the steam pipe 52. The steam pipe connecting portion 6121 communicates with a plurality of flow paths 663 described later in the groove member 66A. As will be described in detail later, the working fluid of the gas phase flowing through the plurality of flow paths 663 flows into the steam pipe 52 via the steam pipe connecting portion 6121.

As shown in FIGS. 5 and 6, the sealing member 613 seals between the first housing 611 and the second housing 612 to suppress leakage of the working fluid to the outside of the housing 61. The sealing member 613 is an annular member corresponding to the outer diameter shape of the wick 63, which will be described later, and in the center of the sealing member 613, the working fluid of the liquid phase stored in the reservoir 614 is placed in the wick 63 in the −Y direction. A hole 6131 that comes into contact with the surface is formed. When the sealing member 613 is viewed from the −Y direction, the center of the sealing member 613 substantially coincides with the center of the wick 63, and the outer edge of the sealing member 613 is located inside the outer edge of the wick 63. The sealing member 613 is arranged.
The sealing member 613 is arranged in the −Y direction with respect to the wick 63 provided in the second housing 612, and is connected to the first housing 611 and the wick 63 so that the first housing 611 It is interposed between the second housing 612 and the second housing 612.

As shown in FIGS. 5 and 6, the reservoir 614 is formed in the first housing 611 by combining the first housing 611 and the second housing 612. The reservoir 614 is a storage unit that stores the working fluid of the liquid phase that flows into the housing 61 via the liquid pipe 54. In other words, the reservoir 614 is a portion of the housing 61 in which the working fluid of the liquid phase that has not been sucked by the wick 63 is stored. That is, the housing 61 has a reservoir 614 inside which stores the working fluid of the liquid phase that has flowed into the housing 61 from the liquid pipe 54.

[Structure of heat exchange unit]
The heat exchange unit 62 is provided in the second housing 612 as described above. The heat exchange unit 62 evaporates the working fluid of the liquid phase supplied from the reservoir 614 by the heat transferred from the light source 411 to be cooled, and generates steam which is the working fluid changed from the liquid phase to the gas phase. Then, the generated steam is discharged to the steam pipe 52.
The heat exchange unit 62 has a wick 63 and a groove member 66A. That is, the evaporation unit 6 has a wick 63 and a groove member 66A that form a heat exchange unit 62. More specifically, the heat exchange unit 62 has a wick 63 and a groove member 66A that are sequentially provided in the + Y direction from the reservoir 614 toward the heat exchange unit 62. Here, the + Y direction is, in other words, a direction from the reservoir 614 toward the groove member 66A.

[Wick configuration]
FIG. 7 is an enlarged view of a part of the heat exchange unit 62.
The wick 63 is infiltrated with the working fluid of the liquid phase stored in the reservoir 614, and transports the working fluid of the infiltrated liquid phase to the groove member 66A side, that is, in the + Y direction. As shown in FIGS. 5 to 7, the wick 63 has a first wick 64 corresponding to the first portion and a second wick 65 corresponding to the second portion. The first wick 64 and the second wick 65 are separate bodies from each other.

[Structure of 1st wick]
The first wick 64 is located in the −Y direction in the wick 63, contacts the working fluid of the liquid phase stored in the reservoir 614, and supplies the working fluid of the liquid phase from the reservoir 614. The first wick 64 transports the working fluid of the liquid phase stored in the reservoir 614 in the + Y direction.
As shown in FIG. 7, the first wick 64 has a plurality of through holes 641 penetrating the first wick 64 in the + Y direction. That is, the plurality of through holes 641 are opened in the first wick 64 in the −Y direction on the reservoir 614 side, and in the first wick 64 in the + Y direction on the second wick 65 side. The working fluid of the liquid phase stored in the reservoir 614 permeates into each of the plurality of through holes 641, and the plurality of through holes 641 causes the working fluid of the soaked liquid phase to permeate in the + Y direction by the capillary force. transport.

Although not shown, a plurality of through holes 641 are arranged in the + X direction and a plurality of through holes 641 are arranged in the + Z direction. Specifically, assuming that the plurality of through holes 641 arranged along the + X direction are one row of through holes 641, the rows of the plurality of through holes 641 arranged along the + Z direction in the entire first wick 64 are arranged for each row. The through holes 641 are staggered in the + X direction. According to this, in the entire first wick 64, the through holes 641 can be arranged more densely than in the case where the plurality of through holes 641 are arranged evenly and uniformly along the + X direction and the + Z direction. The transport efficiency of the working fluid of the liquid phase by 1 wick 64 is improved.
In the present embodiment, the shape of the through hole 641 seen from the −Y direction is a circular shape, but it may be a polygonal shape. When the shape of the through hole 641 is circular, the flow resistance in the through hole 641 can be reduced as compared with the case where the through hole 641 has a polygonal shape.
In such a first wick 64, the portions other than the plurality of through holes 641 are solidly formed of a metal material such as copper or steel use stainless steel (SUS).

[Structure of the second wick]
As shown in FIGS. 5 to 7, the second wick 65 is located in the + Y direction of the wick 63 and comes into contact with the first wick 64 and the groove member 66A. The second wick 65 is impregnated with the working fluid of the liquid phase transported in the + Y direction by the first wick 64, and the second wick 65 transports the working fluid of the liquid phase to the groove member 66A. The second wick 65 has a flat plate-shaped main body portion 651 connected to the first wick 64, and a plurality of sandwiching portions 652. In the present embodiment, the main body portion 651 is in contact with the surface in the + Y direction of the first wick 64.

Each of the plurality of sandwiching portions 652 is arranged at a position where one corresponding convex portion 662 is sandwiched in the groove member 66A. Each of the plurality of sandwiching portions 652 has two connecting portions 653 and 654.
The connecting portions 653 and 654 are protruding portions that protrude from the main body portion 651 in the + Y direction and extend in the + X direction. The connecting portion 653 is connected to the side surface in the + Z direction of one corresponding convex portion 662. The connecting portion 654 is connected to the side surface in the −Z direction in one corresponding convex portion 662. As will be described in detail later, the ends of the connecting portions 653 and 654 in the + Y direction are connected to the base portion 661 described later in the groove member 66A. That is, the two connecting portions 653 and 654 in the second wick 65 are connected to the base portion 661 and one convex portion 662 described later in the groove member 66A.

The second wick 65 has an internal void that holds the working fluid of the liquid phase transported by the first wick 64. The porosity of the second wick 65 is larger than the porosity of the first wick 64. The porosity is a ratio indicating the volume of the void portion per unit volume.
Therefore, the second wick 65 has a property that it is easier to hold the working fluid of the liquid phase than the first wick 64. The second wick 65 functions like a second reservoir that holds the working fluid of the liquid phase transported from the reservoir 614 by the first wick 64 and supplies the held working fluid of the liquid phase to the groove member 66A.
On the other hand, the thermal conductivity of the second wick 65 is higher than the thermal conductivity of the first wick 64. Therefore, heat is conducted from the groove member 66A to the second wick 65, and the working fluid of the liquid phase can be evaporated in the second wick 65. In addition, since the thermal conductivity of the first wick 64 is smaller than the thermal conductivity of the second wick 65, heat is transferred from the second wick 65 to the first wick 64, and the reservoir 614 in the first wick 64. It is suppressed that the temperature of the side end rises, and thus the temperature and pressure in the reservoir 614 rise.

[Structure of groove member]
The groove member 66A is connected to the wick 63, and the heat of the light source 411 to be cooled is transferred. The groove member 66A evaporates the working fluid of the liquid phase transported by the wick 63 by the heat transferred from the light source 411 via the second housing 612, and turns the working fluid of the liquid phase into the working fluid of the gas phase. Change. The groove member 66A guides steam, which is the working fluid of the gas phase, to the steam pipe connecting portion 6121 and eventually to the steam pipe 52. As shown in FIG. 7, the groove member 66A has a base portion 661, a plurality of convex portions 662, and a plurality of flow paths 663.
In the present embodiment, the groove member 66A is configured as a separate body from the second housing 612. However, not limited to this, the groove member 66A may be a part of the second housing 612. In other words, the groove member 66A may be integrated with the second housing 612.

[Base configuration]
The base portion 661 is connected to the inner surface of the second housing 612 facing the −Y direction so as to be heat transferable, and the heat of the light source 411 is transferred to the base portion 661 via the second housing 612. The base portion 661 is formed in a flat plate shape.

[Convex structure]
The plurality of convex portions 662 are protrusions that project from the base portion 661 in the −Y direction on the reservoir 614 side and extend along the + X direction. The plurality of convex portions 662 are connected to the wick 63 in the −Y direction. The + Y direction portions of each of the plurality of convex portions 662 are connected by the base portion 661. In this embodiment, each convex portion 662 projects from the base portion 661 in a square columnar shape.

The + Y direction surface 662A, the + Z direction surface 662B, and the −Z direction surface 662C in each of the plurality of convex portions 662 are covered by the second wick 65.
More specifically, one convex portion 662 corresponds to one sandwiching portion 652. The surface 662A in the −Y direction of one convex portion 662 faces the main body portion 651 of the second wick 65 in the −Y direction and is connected to the main body portion 651. The surface 662B in the + Z direction of one convex portion 662 faces the connecting portion 653 located in the + Z direction in the corresponding sandwiching portion 652 in the + Z direction and is connected to the connecting portion 653. The surface 662C in the −Z direction in one convex portion 662 faces the connecting portion 654 located in the −Z direction in the corresponding sandwiching portion 652 in the −Z direction and is connected to the connecting portion 654.
In order to connect the second wick 65 and the groove member 66A so that the connecting portions 653 and 654 constituting the holding portion 652 come into contact with the convex portion 662, for example, the second wick 65 is fitted into the groove member 66A. A method of inserting the groove member 66A and a method of sintering the second wick 65 are proposed.

By connecting the convex portions 662 to the second wick 65 so as to cover them in the −Y direction and the ± Z direction, the contact area between the second wick 65 holding the working fluid of the liquid phase and the groove member 66A, that is, , The contact area between the working fluid of the liquid phase and the groove member 66A can be expanded. Therefore, as compared with the case where only the surface 662A is connected to the wick 63, the area of the evaporation portion where the working fluid of the liquid phase is evaporated can be expanded, and the evaporation efficiency of the working fluid of the liquid phase can be improved.

[Composition of flow path]
The plurality of flow paths 663 are flow paths through which the working fluid changed from the liquid phase to the gas phase flows. Each of the plurality of flow paths 663 is provided between two adjacent convex portions 662. Specifically, the plurality of flow paths 663 is a space surrounded by the base portion 661, the plurality of convex portions 662, and the second wick 65 of the wick 63. More specifically, as shown in FIG. 7, each of the plurality of flow paths 663 is located in the −Z direction with respect to the convex portion 662 located in the + Z direction among the two adjacent convex portions 662 in the + Z direction. It is a space surrounded by the connecting portion 654, the connecting portion 653 located in the + Z direction with respect to the convex portion 662 located in the −Z direction, the base portion 661, and the main body portion 651.

[Concave structure]
FIG. 8 is an enlarged view showing a part of the groove member 66A. More specifically, FIG. 8 is an enlarged view of the recess 6611 provided in the base 661.
The base 661 has a plurality of recesses 6611 at least at positions facing the second wick 65, as shown in FIGS. 7 and 8. More specifically, the plurality of recesses 6611 are provided in the base portion 661 at positions facing the two connecting portions 653 and 654 in the + Y direction. The plurality of concave portions 6611 extend along the extending direction of the convex portion 662, in other words, the extending direction of the plurality of flow paths 663, which is the + X direction. In the present embodiment, the recess 6611 is a groove provided in the base 661 between each of the plurality of convex portions 662 along the + Z direction.
As described above, the ends of the connecting portions 655 and 654 in the + Y direction are connected to the base portion 661.

[Change of working fluid from liquid phase to gas phase]
The working fluid of the liquid phase stored in the reservoir 614 is transported in the + Y direction through the through hole 641 of the first wick 64 by capillary force to reach the second wick 65.
The working fluid of the liquid phase that has reached the second wick 65 permeates into the main body portion 651. Of the working fluid of the liquid phase that has soaked into the main body 651, some of the working fluid is evaporated by the heat transferred from the surface 662A of the convex portion 662 in contact with the main body 651, and the other part of the working fluid is activated. The fluid is transported from the main body portion 651 to the connection portion 653,654. Of the liquid phase working fluids that have soaked into the connections 653,654, some working fluids are evaporated by the heat transferred from the surfaces 662B, 662C of the convex parts 662, and some other working fluids are , It is transported in the + Y direction, which is the protruding direction of the connecting portions 653,654. The liquid phase working fluid that reaches the + Y direction end of the connection 653,654 forms a film of the liquid phase working fluid between the + Y end of the connection 653,654 and the base 661. .. The working fluid of the liquid phase that has reached the base 661 enters the recess 6611.

As a result, the contact area of the liquid phase with the working fluid at the base portion 661 can be expanded, and the area of the evaporation portion of the working fluid of the liquid phase can be expanded as compared with the case where the recess 6611 is not provided. Therefore, the evaporation efficiency of the working fluid of the liquid phase can be increased.
In particular, the base portion 661 is closer to the light source 411 than the end portion in the + Y direction in which the convex portion 662 comes into contact with the main body portion 651. Therefore, the temperature of the base portion 661 tends to be higher than the temperature of the convex portion 662. By providing the recess 6611 in such a base portion 661 to expand the contact area of the working fluid of the liquid phase, the evaporation efficiency of the working fluid of the liquid phase can be further improved.
Then, the working fluid that has changed from the liquid phase to the gas phase flows into the flow path 663 from the evaporation site and also flows into the flow path 663 via the connecting portions 655 and 654. The working fluid of the gas phase that has flowed into the flow path 663 flows through the flow path 663 and eventually reaches the steam pipe 52 via the steam pipe connection portion 6121.

[Action of recesses in groove members]
According to the boiling curve that expresses the form of the boiling phenomenon of the liquid by the relationship between the heat transfer surface superheat degree and the heat flux, as the heat transfer surface superheat degree increases, the state of the liquid in contact with the heat transfer surface becomes a non-boiling state. From, the transition to the nucleate boiling state, the transition boiling state, and the membrane boiling state. The degree of heat transfer surface superheat is the temperature obtained by subtracting the saturation temperature of the liquid from the temperature of the heat transfer surface, and the heat flow velocity indicates the amount of heat transferred to the liquid.
The non-boiling state is a state in which the temperature of the conduction surface is low, and heat conduction from the heat transfer surface to the liquid continues due to natural convection.
The nucleate boiling state is a boiling state that occurs when the degree of superheat on the heat transfer surface exceeds a certain value, and is a state in which steam (bubbles) is generated from foamed nuclei randomly distributed on the heat transfer surface. In the nucleate boiling state, the heat flux to the liquid is high, and the evaporation efficiency of the liquid is high.
The transition boiling state is a state in which the foaming cycle of steam is shortened as the number of foaming nuclei increases, and the heat transfer surface is partially covered by steam. In the transition boiling state, the heat flux to the liquid is low and the evaporation efficiency of the liquid is not high.
The film boiling state is a state in which the entire surface of the heat transfer surface is covered with a vapor film, and boiling occurs directly from the contact surface between the vapor film and the liquid. In the boiling state of the membrane, the heat flux to the liquid is high, and the evaporation efficiency of the liquid is high.

Therefore, in order to efficiently evaporate a liquid such as a working fluid in a liquid phase, it is desired to maintain a nucleate boiling state or a film boiling state in which the heat flow velocity to the liquid is high. Of these, the film boiling state is the boiling state after passing through the nucleate boiling state and the transition boiling state, and the temperature of the groove member 66A to which the heat of the light source 411 is transferred reaches the temperature at which the film boiling state occurs. It's hard. From this, it is conceivable to maintain the nucleate boiling state and increase the evaporation efficiency of the working fluid in the liquid phase.

In the present embodiment, each of the plurality of recesses 6611 extending in the + X direction in the base portion 661 is a fine groove having a substantially V-shaped cross section along the YZ plane orthogonal to the + X direction. A plurality of them are arranged along the + Z direction.
When the liquid evaporates in such a substantially V-shaped recess 6611, the bubbles generated in the foam nuclei in the recess 6611 are quickly discharged from the recess 6611 and the bubbles do not grow. From this, the heat transfer from the surface of the recess 6611, which is the heat transfer surface, to the working fluid of the liquid phase is not hindered by air bubbles, and the decrease in heat flux of the liquid phase to the working fluid is suppressed. .. Therefore, the evaporation efficiency of the working fluid of the liquid phase is enhanced.
Such a substantially V-shaped recess 6611 can be formed by, for example, cutting.

[Effect of the first embodiment]
The projector 1 according to the present embodiment described above has, for example, the following effects.
The projector 1 includes a light source 411 that emits light, an optical modulator 343 that modulates the light emitted from the light source 411, a projection optical device 36 that projects light modulated by the optical modulator 343, and a cooling device 5. , Equipped with.
The cooling device 5 includes an evaporation unit 6, a vapor pipe 52, a condensing unit 53, and a liquid pipe 54. The evaporation unit 6 evaporates the working fluid of the liquid phase by the heat transferred from the light source 411 to be cooled, and changes the working fluid of the liquid phase into the working fluid of the gas phase. The vapor pipe 52 circulates the working fluid changed from the liquid phase to the gas phase in the evaporation unit 6 to the condensing unit 53. The condensing unit 53 condenses the working fluid of the gas phase and changes the working fluid of the gas phase into the working fluid of the liquid phase. The liquid pipe 54 circulates the working fluid changed from the gas phase to the liquid phase in the condensing unit 53 to the evaporation unit 6.

The evaporating unit 6 is provided in a housing 61 having a reservoir 614 connected to the liquid pipe 54 and storing the working fluid of the liquid phase flowing into the housing 61, and the working fluid of the liquid phase is immersed in the housing 61. It includes a wick 63 that includes and transports the working fluid of the liquid phase, and a groove member 66A that is connected to the wick 63 and transfers the heat of the light source 411.
The groove member 66A has a base portion 661, a plurality of convex portions 662, and a plurality of flow paths 663. The plurality of convex portions 662 project from the base portion 661 and are connected to the wick 63. The plurality of flow paths 663 are surrounded by a base portion 661, a plurality of convex portions 662, and a wick 63, and a working fluid changed from a liquid phase to a gas phase flows.
The wick 63 has a first wick 64 as a first portion to which the working fluid of the liquid phase is supplied from the reservoir 614, and the working fluid of the liquid phase is transported from the first wick 64 and is connected to the base 661 and the convex portion 662. It has a second wick 65 as a second part.
The base 661 has a plurality of recesses 6611 at positions facing the second wick 65.

According to such a configuration, the contact area of the liquid phase with the working fluid at the base portion 661 and the convex portion 662, that is, the contact area between the groove member 66A and the working fluid of the liquid phase can be expanded. Therefore, the area of the evaporation site of the working fluid of the liquid phase can be expanded.
Here, the plurality of convex portions 662 project from the base portion 661 in the −Y direction. Therefore, in the heat transfer path transmitted from the light source 411, the temperature of the base portion 661 located upstream of the end portion in the −Y direction of the convex portion 662 is the temperature of the end portion in the −Y direction of the convex portion 662. Will be higher than. As a result, the evaporation efficiency of the working fluid of the liquid phase in the base portion 661 in which the contact area of the liquid phase with the working fluid is expanded by the recess 6611 can be further increased.
Further, since the recess 6611 is provided in the base portion 661 forming a part of the outer edge of the flow path 663, the working fluid changed from the liquid phase to the gas phase in the recess 6611, that is, the vapor of the working fluid is introduced. It can be easily guided to the flow path 663. As a result, the change of the working fluid from the liquid phase to the gas phase can be promoted, and the evaporation efficiency of the working fluid of the liquid phase can be improved.
Therefore, the cooling efficiency of the object to be cooled can be increased.

The first wick 64 as the first part and the second wick 65 as the second part are separate bodies from each other.
According to such a configuration, the configuration of the first wick 64 and the configuration of the second wick 65 can be made different, and the material of the first wick 64 and the material of the second wick 65 can be made different. Therefore, the versatility of the wick 63 can be increased.

The porosity of the second wick 65 is larger than the porosity of the first wick 64.
According to such a configuration, the second wick 65 can easily hold the working fluid of the liquid phase, whereby the working fluid of the liquid phase can be quickly supplied to the groove member 66A. In addition, the working fluid that has changed from the liquid phase to the gas phase can be easily discharged to the flow path 663 via the second wick 65.
Further, since the porosity of the first wick 64 is smaller than the porosity of the second wick 65, it is possible to prevent the working fluid of the gas phase from passing through the first wick 64 toward the reservoir 614. Therefore, it is possible to suppress the inflow of the working fluid of the gas phase into the reservoir 614 and the increase in the pressure in the reservoir 614.

The plurality of recesses 6611 are grooves extending along the plurality of flow paths 663.
According to such a configuration, the vapor of the working fluid generated in the recess 6611 can be easily guided to the flow path 663. In addition, it is possible to easily form a plurality of recesses 6611 in the base portion 661 by cutting or the like.

The first wick 64 has a plurality of through holes 641 penetrating the first wick 64 in the −Y direction from the reservoir 614 toward the groove member 66A.
According to such a configuration, the working fluid of the liquid phase stored in the reservoir 614 through the plurality of through holes 641 can be easily transported to the second wick 65, and thus to the groove member 66A. Therefore, the transport efficiency of the working fluid of the liquid phase can be increased, and the evaporation efficiency of the working fluid of the liquid phase can be increased.

The second wick 65 has a main body portion 651 and a plurality of connecting portions 653, 654. The main body 651 is connected to the first wick 64. The plurality of connecting portions 653, 654 project from the main body portion 651 in the + Y direction from the reservoir 614 toward the groove member 66A, and are connected to each of the base portion 661 and the plurality of convex portions 662. The plurality of recesses 6611 are provided in the base portion 661 at positions facing the plurality of connecting portions 653 and 654 in the + Y direction.
According to such a configuration, the second wick 65 and the base portion 661 can be easily connected. As a result, it is possible to easily allow the working fluid of the liquid phase to enter the recess 6611, so that the working fluid of the liquid phase can be easily evaporated at the base portion 661. Therefore, the evaporation efficiency of the working fluid of the liquid phase can be further increased, and the cooling efficiency of the light source 411 to be cooled can be further increased.
Further, a part of the working fluid of the liquid phase transported by the connecting portions 653 and 654 can be brought into contact with the convex portion 662. As a result, the working fluid of the liquid phase can be easily evaporated by the heat of the light source 411 transmitted to the convex portion 662. Therefore, the area of the evaporation portion of the working fluid of the liquid phase can be expanded, and the cooling efficiency of the light source 411 can be improved.
In the present embodiment, the two connecting portions 653 and 654 are connected to the one convex portion 662 so as to sandwich the one convex portion 662 in the ± Z direction. According to this, the area of the evaporation portion of the working fluid of the liquid phase can be expanded as compared with the case where only one of the connecting portions 653 and 654 is connected to the one convex portion 662. Therefore, the cooling efficiency of the light source 411, which is the object of cooling, can be further improved.

[First Modified Example of First Embodiment]
In the groove member 66A, the recess 6611 provided in the base portion 661 is a groove portion extending along the + X direction, and the cross-sectional shape of the recess 6611 along the YZ plane is assumed to be substantially V-shaped. However, not limited to this, the cross-sectional shape of the recess along the YZ plane may be arcuate. The arc shape in this case may be a semicircular shape or a semi-elliptical shape. Further, the cross-sectional shape of the recess along the YZ plane may be a polygonal shape of a square or more.

FIG. 9 is an enlarged view showing a part of the groove member 66B, which is a modification of the groove member 66A. More specifically, FIG. 9 is a view showing a cross section of the recess 6641 provided in the base portion 664 of the groove member 66B along the YZ plane.
For example, instead of the groove member 66A, the groove member 66B shown in FIG. 9 may be adopted for the evaporation unit 6.
The groove member 66B has the same configuration and function as the groove member 66A except that the groove member 66B has a base portion 664 instead of the base portion 661. That is, the groove member 66B includes a base portion 664, a plurality of convex portions 662 projecting from the base portion 664 in the −Y direction, a base portion 664, a plurality of convex portions 662, and a plurality of flow paths 663 surrounded by the second wick 65. Has.

Like the base 661, the base 664 connects the ends of the plurality of convex portions 662 in the + Y direction. The base portion 664 has a plurality of recesses 6641 at positions facing each other in the + Y direction with the plurality of connecting portions 653, 654 constituting the plurality of sandwiching portions 652.
Each of the plurality of recesses 6641 is a groove portion extending along the + X direction, which is the extension direction of the plurality of convex portions 662. The plurality of recesses 6641 are arranged along the + Z direction.
The recess 6641 functions in the same manner as the recess 6611 in which the cross section along the YZ plane is a substantially semicircular groove and the cross section along the YZ plane is a substantially V-shaped groove.
A cooling device 5 having an evaporation unit 6 having such a groove member 66B instead of the groove member 66A can also achieve the same effect as the cooling device 5 having an evaporation unit 6 having the groove member 66A.

[Second variant of the first embodiment]
The recess 6611 of the groove member 66A was provided at a position of the base portion 661 facing the connecting portions 653 and 654 in the + Y direction. However, the present invention is not limited to this, and the concave portion 6611 may be provided between the two adjacent convex portions 662 in the base portion 661 without a gap in the + Z direction. That is, the recess 6611 may be provided at a portion of the base portion 661 that directly faces the flow path 663. The same applies to the recess 6641.
Further, the number of the recesses 6611, 6641 does not matter as long as the recesses 6611, 6641 are provided at positions facing the connecting portions 653, 654 in the base portion 661, 664 in the + Y direction.

[Second Embodiment]
Next, a second embodiment of the present disclosure will be described.
The projector according to the present embodiment has the same configuration as the projector 1 according to the first embodiment. However, the projector according to the present embodiment is different from the projector 1 in that the shape of the recess provided at the base of the groove member is different. In the following description, parts that are the same as or substantially the same as those already described will be designated by the same reference numerals and description thereof will be omitted.

FIG. 10 is an enlarged view showing a part of the groove member 66C included in the cooling device 5 included in the projector according to the present embodiment. More specifically, FIG. 10 is a view of the recess 6651 provided in the base portion 665 of the groove member 66C as viewed from the −Y direction.
The projector according to the present embodiment has the same configuration and function as the projector 1 according to the first embodiment, except that the projector includes the cooling device 5 having the groove member 66C shown in FIG. 10 instead of the groove member 66A. The cooling device 5 in the present embodiment also cools the light source 411 to be cooled.

Similar to the groove members 66A and 66B of the first embodiment, the groove member 66C evaporates the working fluid of the liquid phase transported from the reservoir 614 in the + Y direction by the wick 63, and makes the working fluid of the liquid phase vapor. It is changed to a working fluid, and steam, which is a working fluid of the gas phase, is guided to the steam pipe 52. The groove member 66C has the same configuration and function as the groove member 66A, except that the groove member 66C has a base portion 665 provided with a plurality of recesses 6651 instead of the base portion 661 provided with the plurality of recesses 6611. That is, the groove member 66C includes a base portion 665, a plurality of convex portions 662 projecting from the base portion 665 in the −Y direction, and a plurality of flow paths 663 surrounded by the base portion 665, the plurality of convex portions 662, and the second wick 65. Has.

The base portion 665 has a plurality of recesses 6651 at positions facing the plurality of connecting portions 653, 654 in the + Y direction.
The plurality of recesses 6651 are holes having a bottom, and a plurality of recesses are arranged in the + X direction and a plurality of recesses are arranged in the + Z direction. The recess 6651 is formed in the base 665 by, for example, laser irradiation.
In the present embodiment, the concave portion 6651 is provided on substantially the entire surface between the plurality of convex portions 662 at the base portion 665. However, the present invention is not limited to this, and the recess 6651 may be provided only at a portion of the base portion 665 facing the connecting portions 653 and 654.
Further, the recess 6651 may be a hole having a bottom, and the shape of the recess 6651 may be substantially hemispherical, substantially semi-elliptical, or substantially semi-polyhedral. ..

[Effect of the second embodiment]
According to the projector according to the present embodiment described above, the same effect as that of the projector 1 according to the first embodiment can be obtained, and the following effects can be obtained.
The plurality of recesses 6651 are holes having a bottom.
According to such a configuration, similarly to the groove members 66A and 66B of the first embodiment in which the recesses 6611 and 6641 which are the grooves are provided, the groove member in which the recess is not provided in the base is adopted for the evaporation portion 6. The area of the evaporation site of the working fluid of the liquid phase can be further expanded as compared with the case where. Therefore, the cooling efficiency of the light source 411, which is the object of cooling, can be increased.

[Modification of Embodiment]
The present disclosure is not limited to each of the above embodiments, and modifications, improvements, etc. to the extent that the object of the present disclosure can be achieved are included in the present disclosure.
In each of the above embodiments, the second wick 65 as the second portion has a connecting portion 653, 654 that sandwiches the convex portion 662 in the ± Z direction. However, the present invention is not limited to this, and the second wick 65 may have a configuration having only one of the connecting portions 653 and 654. That is, the second wick may have a connecting portion connected to only one of the + Z-direction surface and the −Z-direction surface of the convex portion 662. Further, at least one of the connecting portions 653 and 654 of the second wick 65 may be in contact with the base portion 661,664,665 and may not be in contact with the convex portion 662. The same applies when the second wick 65 has only one of the connecting portions 653 and 654.

In each of the above embodiments, the wick 63 has a first wick 64 and a second wick 65, and the first wick 64 and the second wick 65 are separate from each other. However, the present invention is not limited to this, and the wick 63 may have a first portion corresponding to the first wick 64 and a second portion corresponding to the second wick 65 integrally configured. That is, the wick may be one wick in which each of the first portion and the second portion is made of the same material. For example, a wick 63 that does not include the first wick 64 may be adopted. In this case, the second wick 65 may be used as the wick 63.
Further, for example, the first portion and the second portion may be integrated by sintering or the like.

In each of the above embodiments, the porosity of the second wick 65 is larger than the porosity of the first wick 64. That is, the porosity of the second portion in the wick 63 is larger than the porosity of the first portion. However, not limited to this, the porosity of the second portion in the wick may be equal to or less than the porosity of the first portion.

In the first embodiment, each of the plurality of recesses 6611 and 6641 provided in the bases 661 and 664 in the groove members 66A and 66B is a groove portion extending along the + X direction which is the extension direction of the convex portion 662. There was. In the second embodiment, each of the plurality of recesses 6651 provided in the base portion 665 of the groove member 66C is a hole having a bottom. However, the shape of the recess provided at the base of the groove member is not particularly limited. For example, the recess may be a grid-like groove provided at the base. Further, for example, both a recess which is a groove and a recess which is a hole may be provided in the base portion.

In each of the above embodiments, the first wick 64 as the first portion has a plurality of through holes 641 penetrating the first wick 64 in the + Y direction from the reservoir 614 toward the groove members 66A to 66C. However, the present invention is not limited to this, and the first portion of the wick may have a configuration that does not have a plurality of through holes. For example, each of the first wick and the second wick may be composed of glass, resin, metal fibers, or the like, and may include voids inside. Also in this case, the porosity of the second wick may or may not be larger than the porosity of the first wick.

In each of the above embodiments, the plurality of recesses 6611, 6641, 6651 are provided at positions of the bases 661,664,665 facing the connecting portions 653,654 in the + Y direction. However, the present invention is not limited to this, and if at least one recess 6611, 6641, 6651 is provided in the base portion 661,664,665 at a position facing the connecting portion 653,654 in the + Y direction, the recess 6611,6641, The position and number of 6651 does not matter.

In each of the above embodiments, the groove members 66A, 66B, 66C are different from the second housing 612 constituting the housing 61. However, the present invention is not limited to this, and the groove members 66A, 66B, 66C and the second housing 612 may be integrated.

In each of the above embodiments, the wick 63 and the groove members 66A, 66B, 66C are formed in a substantially rectangular shape when viewed from the −Y direction. However, not limited to this, the shapes of the wick 63 and the groove members 66A, 66B, 66C when viewed from the −Y direction can be changed as appropriate. For example, the shape of the groove members 66A, 66B, 66C when viewed from the −Y direction may be a substantially circular shape. The same applies to the wick 63 and the housing 61.

In each of the above embodiments, the light source 411 of the light source device 4 has semiconductor lasers 421 and 413. However, the light source device is not limited to this, and may have a light source lamp such as an ultra-high pressure mercury lamp or another solid light source such as an LED (Light Emitting Diode) as a light source. In this case, the cooling target of the cooling device 5 may be a light source lamp or another solid-state light source.
Further, the cooling target of the cooling device 5 is not limited to the light source 411, and may have other configurations. For example, the cooling device 5 may cool optical components such as the optical modulation device 343 and the polarization conversion element 313, or may cool the circuit elements provided in the control device and the power supply device.

In each of the above embodiments, the projector includes three optical modulation devices 343. However, the present disclosure is not limited to this, and the present disclosure can be applied to a projector provided with two or less or four or more optical modulation devices.
In each of the above embodiments, the light modulation device 343 is a transmissive liquid crystal panel in which the light incident surface and the light emitting surface are different from each other. However, the present invention is not limited to this, and a reflective liquid crystal panel in which the light incident surface and the light emitting surface are the same may be used as the light modulation device. Further, if it is an optical modulation device capable of forming an image according to image information by modulating an incident light beam, a device using a micromirror, for example, a device using a DMD (Digital Micromirror Device) or the like, other than liquid crystal An optical modulator may be used.
In each of the above embodiments, the image projection device 3 illustrates a configuration having the layout and optical components shown in FIG. However, the present invention is not limited to this, and an image projection device having other layouts and optical components may be adopted.

In each of the above embodiments, an example in which the cooling device 5 provided with the loop type heat pipe 51 is applied to the projector is given. However, the present invention is not limited to this, and the cooling device of the present disclosure can be applied to devices and devices other than the projector, and can also be used alone. That is, the application of the cooling device of the present disclosure is not limited to cooling the components of the projector.

[Summary of this disclosure]
The following is a summary of the present disclosure.
The cooling device according to the first aspect of the present disclosure includes an evaporating unit that evaporates the working fluid of the liquid phase by heat transferred from the object to be cooled and changes the working fluid of the liquid phase into the working fluid of the gas phase. The condensed part that condenses the working fluid in the gas phase and changes the working fluid in the gas phase into the working fluid in the liquid phase, and the condensed working fluid that changes from the liquid phase to the gas phase in the evaporation part. A steam pipe for flowing to the unit and a liquid pipe for flowing the working fluid changed from the gas phase to the liquid phase in the condensing part to the evaporating part are provided, and the evaporating part is connected to the liquid pipe. A housing having a reservoir for storing the working fluid of the liquid phase that has flowed into the inside, and a wick provided in the housing in which the working fluid of the liquid phase permeates and transports the working fluid of the liquid phase. The groove member comprises a groove member connected to the wick and to which heat to be cooled is transferred, and the groove member includes a base portion, a plurality of convex portions projecting from the base portion and connected to the wick, and the groove member. It has a base, a plurality of protrusions, and a plurality of flow paths through which the working fluid changed from a liquid phase to a gas phase flows, which is surrounded by the wick, and the wick is the operation of the liquid phase from the reservoir. The base has a first portion to which the fluid is supplied and a second portion to which the working fluid of the liquid phase is transported from the first portion and is connected to the base portion and the plurality of convex portions. It is characterized by having a plurality of recesses at positions facing the second portion.

According to such a configuration, the base portion of the groove member to which the heat to be cooled is transferred has a plurality of recesses at positions facing the second portion where the working fluid of the liquid phase is transported by the first portion. Thereby, the contact area of the liquid phase with the working fluid at the base, that is, the area of the evaporation portion of the working fluid of the liquid phase in the groove member can be expanded.
Here, in the heat transfer path transferred from the cooling target, the base portion is located on the upstream side of the convex portion, so that the temperature of the base portion is higher than the temperature of the convex portion. Therefore, the contact area of the liquid phase with the working fluid at the base can be expanded, so that the evaporation efficiency of the working fluid of the liquid phase can be improved.
Further, since the recess is provided at the base portion forming the outer edge of the flow path, the vapor of the working fluid generated in the recess can be easily guided to the flow path. As a result, the change of the working fluid from the liquid phase to the gas phase can be promoted, so that the heat consumption of the object to be cooled can be promoted.
Therefore, the cooling efficiency of the object to be cooled can be increased.

In the first aspect, it is preferable that the first portion and the second portion are separate from each other.
According to such a configuration, the configuration of the first portion and the configuration of the second portion can be made different, and the material of the first portion and the material of the second portion can be made different. Therefore, the versatility of the wick can be increased.

In the first aspect, the porosity of the second portion is preferably larger than the porosity of the first portion.
According to such a configuration, it is possible to easily hold the working fluid of the liquid phase in the second portion, whereby the working fluid of the liquid phase can be quickly supplied to the groove member. In addition, the vapor of the working fluid can be easily discharged to the flow path via the second portion.
Further, the porosity of the first portion is smaller than the porosity of the second portion. According to this, even when the vapor of the working fluid passes through the second portion to the reservoir side, it is possible to prevent the vapor of the working fluid from passing through the first portion to the reservoir side. Therefore, it is possible to prevent the vapor of the working fluid from flowing into the reservoir and the pressure in the reservoir from rising.

In the first aspect, it is preferable that at least one of the plurality of recesses is a groove extending along the plurality of flow paths.
According to such a configuration, it is possible to easily guide the vapor of the working fluid generated in the recess to the flow path. In addition, it is possible to easily form a recess in the base portion by cutting or the like.

In the first aspect, it is preferable that at least one of the plurality of recesses is a hole having a bottom.
According to such a configuration, the area of the evaporation site can be further expanded. Therefore, the cooling efficiency of the object to be cooled can be increased.

In the first aspect, it is preferable that the first portion has a plurality of through holes penetrating the first portion in a direction from the reservoir toward the groove member.
According to such a configuration, the working fluid of the liquid phase stored in the reservoir through the plurality of through holes can be easily transported to the second portion, and thus to the groove member. Therefore, the transport efficiency of the working fluid of the liquid phase can be increased, and the evaporation efficiency of the working fluid of the liquid phase can be increased.

In the first aspect, the second portion projects from the main body portion connected to the first portion and the main body portion in a direction from the reservoir toward the groove member, and the base portion and the plurality of convex portions. It has a plurality of connecting portions connected to each of the plurality of connecting portions, and the plurality of recesses are provided at the base portion at positions facing the plurality of connecting portions in a direction from the reservoir to the groove member. Is preferable.
According to such a configuration, it is possible to easily connect the second portion and the base portion. This makes it easier for the working fluid of the liquid phase to enter the recess, so that the working fluid of the liquid phase can be easily evaporated at the base. Therefore, the evaporation efficiency of the working fluid of the liquid phase can be further increased, and the cooling efficiency of the light source to be cooled can be further increased.
Further, a part of the working fluid of the liquid phase transported by the connecting portion can be brought into contact with the convex portion. As a result, the working fluid of the liquid phase held in the connecting portion can be evaporated by the heat of the cooling target transmitted to the convex portion. Therefore, the area of the evaporation portion of the working fluid of the liquid phase can be expanded, and the cooling efficiency of the cooling target can be improved.

The projector according to the second aspect of the present disclosure includes a light source that emits light, an optical modulator that modulates the light emitted from the light source, and a projection optical apparatus that projects light modulated by the optical modulator. It is characterized by including the above-mentioned cooling device.
According to such a configuration, the same effect as that of the cooling device described above can be obtained.

In the second aspect, it is preferable that the cooling target is the light source.
According to such a configuration, the light source can be efficiently cooled.

1 ... Projector, 343 (343B, 343G, 343R) ... Optical modulator, 36 ... Projection optical device, 411 ... Light source (cooling target), 5 ... Cooling device, 52 ... Steam tube, 53 ... Condensing section, 54 ... Liquid tube , 6 ... Evaporation part, 61 ... Housing, 61B ... Bottom part, 611 ... First housing, 612 ... Second housing, 614 ... Reservoir, 63 ... Wick, 64 ... First wick (first part), 641 ... Through hole, 65 ... 2nd wick (second part), 651 ... Main body, 652 ... Holding part, 653,654 ... Connection part, 66A, 66B, 66C ... Groove member, 661,664,665 ... Base, 6611 , 6641,6651 ... concave, 662 ... convex, 662A, 662B, 662C ... surface, 663 ... flow path.

Claims (9)

An evaporating part that evaporates the working fluid of the liquid phase by the heat transferred from the object to be cooled and changes the working fluid of the liquid phase into the working fluid of the gas phase.
A condensing part that condenses the working fluid in the gas phase and changes the working fluid in the gas phase into the working fluid in the liquid phase.
A vapor pipe that circulates the working fluid that has changed from a liquid phase to a gas phase in the evaporation section to the condensing section.
A liquid pipe for circulating the working fluid changed from a gas phase to a liquid phase in the condensing part to the evaporating part is provided.
The evaporation part is
A housing connected to the liquid pipe and having a reservoir for storing the working fluid of the liquid phase that has flowed into the inside.
A wick provided in the housing, in which the working fluid of the liquid phase permeates and transports the working fluid of the liquid phase,
A groove member that is connected to the wick and that transfers heat to be cooled is provided.
The groove member is
At the base,
A plurality of protrusions protruding from the base and connected to the wick,
It has a base, a plurality of protrusions, and a plurality of flow paths in which the working fluid changed from a liquid phase to a gas phase flows, which is surrounded by the wick.
The wick
The first part to which the working fluid of the liquid phase is supplied from the reservoir, and
The working fluid of the liquid phase is transported from the first portion, and has a base portion and a second portion connected to the plurality of convex portions.
The cooling device is characterized in that the base portion has a plurality of recesses at positions facing the second portion. In the cooling device according to claim 1,
A cooling device characterized in that the first portion and the second portion are separate bodies from each other. In the cooling device according to claim 1 or 2.
A cooling device characterized in that the porosity of the second portion is larger than the porosity of the first portion. In the cooling device according to any one of claims 1 to 3.
A cooling device, wherein at least one of the plurality of recesses is a groove extending along the plurality of flow paths. In the cooling device according to any one of claims 1 to 3.
A cooling device, wherein at least one of the plurality of recesses is a hole having a bottom. In the cooling device according to any one of claims 1 to 5.
The cooling device is characterized in that the first portion has a plurality of through holes penetrating the first portion in a direction from the reservoir toward the groove member. In the cooling device according to any one of claims 1 to 6.
The second part is
The main body connected to the first part and
It has a plurality of connecting portions that protrude from the main body portion in a direction from the reservoir toward the groove member and are connected to the base portion and each of the plurality of convex portions.
The cooling device is characterized in that the plurality of recesses are provided at a position facing the plurality of connecting portions in the direction from the reservoir toward the groove member at the base portion. A light source that emits light and
An optical modulator that modulates the light emitted from the light source,
A projection optical device that projects light modulated by the light modulator,
A projector comprising the cooling device according to any one of claims 1 to 7. In the projector according to claim 8,
The projector to be cooled is the light source.

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