JP5565517B1 - Cooling device, cooling structure, image projection device, electronic equipment - Google Patents

Abstract

At the same time as increasing the cooling capacity of the heat dissipating part, the object to be cooled located downstream of the heat dissipating part is also cooled using the air after cooling the heat dissipating part.
A cooling device including a plurality of fins and a heat radiating unit that radiates heat by contacting a first cooling target, and a blower unit that blows air to the heat radiating unit, The heat radiating portion includes a first region and a second region having a smaller fin interval than the first region, and is different from the first cooling target on the downstream side of the first region of the air flow path. Another second cooling target is located, and the air that has passed through the first region hits the second cooling target.
[Selection] Figure 11

Description

  The present invention relates to a heat sink, a cooling device, a cooling structure, an image projection device, and an electronic apparatus.

  As a method for cooling the heat generating source, a method is known in which a heat radiating plate is pressed against the heat generating source to increase the heat radiating area and cooling air is blown to the heat radiating portion. Further, as a method for increasing the cooling efficiency, for example, a heat sink is formed of a material having high thermal conductivity. By molding the heat sink with a material having high thermal conductivity, it is possible to spread the heat transmitted from the contact portion with the heat source uniformly over the entire heat sink. As a result, since the heat radiation area can be increased, the heat generation source can be efficiently cooled.

  It is also effective to increase the contact area between the cooling air and the heat sink. The heat radiating plate heated by receiving heat from the heat generation source is cooled at the contact point with the cooling air. Therefore, it is possible to increase the cooling efficiency by expanding the contact area with the cooling air. As a method of expanding the contact area, a method of standing fins on the heat sink is already known. By raising the fins with fine pitches and blowing cooling air between the pitches, the contact area with the cooling air is expanded and the cooling efficiency is increased.

  Furthermore, a forced air cooling method is used in which a heat sink is cooled using a fan. The cooling capacity depends on the wind speed of the air passing between the pitches of the fins. Therefore, in order to increase the cooling capacity, it is necessary to increase the wind speed that passes between the pitches, and forced air cooling rather than natural air cooling can provide a higher cooling effect. In addition, a method using a fan is generally used for forced air cooling, and the discharge port of a sirocco fan with a high static pressure is arranged so as to face the fin of the heat sink, and the air discharged from the sirocco fan is directly applied to the fin. It can be said that a cooling structure for spraying is common.

  However, in the conventional cooling method, when the cooling efficiency is structurally increased, the surface area of the heat sink is increased to improve the cooling efficiency, or a more powerful large fan is required. There was a problem of increasing the size. Therefore, in any case, the structure becomes large and heavy, and there is a problem that it is difficult to store the structure in a small and light electric device.

  Further, in the method of reducing the fin pitch, since the cooling air passes between the fin pitches, the ventilation resistance increases when the fin pitch is reduced. Since the cooling capacity depends on the air volume, when the ventilation resistance is increased, the amount of air passing through the fins is reduced, so that it is difficult to use the air after passing through the fins for cooling other parts. That is, when a fan, a heat radiating part, and other cooling objects are arranged in series in the above order, and the cooling air discharged from the fan is used to simultaneously cool not only the heat radiating part but also other cooling objects. If the pitch of the fins is made fine, the cooling capacity of the heat radiating portion is increased, but the cooling object on the downstream side of the heat radiating portion is difficult to cool.

  Therefore, in the conventional method of increasing the cooling capacity by making the pitch finer, the fan is generally cooled only by the heat radiating part. If the air after cooling the heat radiating part is temporarily used, Even if the configuration is such that the parts are cooled, the cooling capacity cannot be expected so much. In addition, when the fin shape is devised to have a complicated shape, there is a problem that the cost of the fin increases. Therefore, ideally, there is a demand for a method of expanding the surface area of the heat radiating portion while having a simple shape.

  The present invention has been made in view of the above-described problems, and at the same time increases the cooling capacity of the heat dissipating part, and at the same time uses the air after cooling the heat dissipating part with respect to the cooling object located downstream of the heat dissipating part An object of the present invention is to propose a heat sink that can be cooled.

In order to solve the above-described problems and achieve the object, the present invention includes a plurality of fins, and the plurality of fins includes at least a first region and a second region, and the first region includes the first region and the second region. A heat sink having a smaller fin pitch in the second region, and a sirocco fan arranged so that more air flows in the second region than in the first region with respect to the heat sink; Fi down of the at the end of the outlet side of the air flow resulting from the sirocco fan, towards the fins of the second region than the fins of the first region and wherein the longer.

  According to the present invention, it is possible to increase the cooling capacity of the heat radiating unit and at the same time to cool the object to be cooled located downstream of the heat radiating unit by using the air after cooling the heat radiating unit. There is an effect.

FIG. 1 is a perspective view illustrating a usage mode of the image projection apparatus according to the embodiment. FIG. 2 is a perspective view illustrating the optical engine unit and the light source device of the embodiment. FIG. 3 is a perspective view illustrating an optical engine unit according to the embodiment. FIG. 4 is a perspective view illustrating the illumination optical unit and the image processing unit of the embodiment. FIG. 5 is a perspective view illustrating an image processing unit according to the embodiment. FIG. 6 is a perspective view illustrating a projection optical unit according to the embodiment. FIG. 7 is a perspective view showing the projection optical unit of the embodiment. FIG. 8 is a side view showing the projection optical unit of the embodiment. FIG. 9 is a perspective view showing the configuration of the heat sink of the embodiment. FIG. 10 is a perspective view showing the configuration of the sirocco fan of the embodiment. FIG. 11 is a bottom view showing the configuration of the sirocco fan of the embodiment. FIG. 12 is a perspective view illustrating a positional relationship between the heat sink and the light source device according to the embodiment. FIG. 13 is a perspective view illustrating a positional relationship between the heat sink and the light source device according to the embodiment. FIG. 14 is a bottom view of the image projection apparatus according to the embodiment. FIG. 15 is a side view of the image projection apparatus according to the embodiment. FIG. 16 is a side view of a conventional image projection apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view showing an image projection apparatus 1 according to the present embodiment as viewed obliquely. The image projection apparatus 1 generates an image based on image data input from a personal computer, a video camera, or the like, and projects and displays the image on a screen 2 that is a projection surface. A liquid crystal projector widely known as the image projection apparatus 1 has recently been improved in the resolution, the price, and the like with an increase in the resolution of the liquid crystal panel and the efficiency of the light source lamp. In addition, compact and lightweight image projection devices using DMD (Digital Micro-mirror Device) have become widespread, and these image projection devices are widely used not only in offices and schools but also at home. In particular, front-type projectors have improved portability and have been used for small meetings of several people.

  FIG. 2 is a perspective view showing a state in which the outer layer cover 3 of the image projection apparatus 1 in FIG. 1 is removed. As shown in FIG. 2, the image projection device 1 is roughly provided with an optical engine unit 30 and a light source device 20. The light source device 20 controls a light source such as a high-pressure mercury lamp, and supplies white light to the optical engine unit 30 for light necessary for image projection.

  The light source device 20 includes a light source bracket 22 that is a holding member that holds the light source 21, and a light source 21 such as a halogen lamp, a metal halide lamp, or a high-pressure mercury lamp is mounted on the light source bracket 22.

  A holder 24 holding a reflector (not shown) is screwed to the light emitting side of the light source 21 above the light source bracket 22. An exit window 23 (see FIG. 3) is provided on the surface of the holder 24 opposite to the light source 21 arrangement side. The light emitted from the light source 21 is collected on the emission window 23 by a reflector (not shown) held by the holder 24 and emitted from the emission window 23.

  Further, a light source air inlet through which air for cooling the light source 21 flows is provided on the side surface of the holder 24, and air heated by the heat of the light source 21 is exhausted on the upper surface of the holder 24. A light source exhaust port 24C is provided.

  The optical engine unit 30 performs processing for processing and projecting input image data using light supplied from the light source device 20. FIG. 3 is a perspective view showing a detailed configuration of the optical engine unit 30. The optical engine unit 30 includes an illumination optical unit 31, a projection optical unit 33, and an image processing unit 32. The white light from the light source device 20 described above is first applied to the illumination optical unit 31. The illumination optical unit 31 splits the white light from the light source device 20 into RGB components and guides them to the image processing unit 32. The image processing unit 32 forms an image according to the modulation signal, and generates an image to be projected from the input image data. The projection optical unit 33 enlarges and projects the image generated by the image processing unit 32 on the irradiated surface.

  FIG. 4 is an arrangement configuration diagram of the illumination optical unit 31 and the image processing unit 32. The illumination optical unit 31 includes a color foil 38, a light tunnel 37, a relay lens 36, a cylinder mirror 35, and a concave mirror 34. The color foil 38 converts the white light emitted from the light source device 20 into light that repeats each color of RGB every unit time by a disk-shaped color filter and emits the light. The light tunnel 37 is formed in a cylindrical shape by laminating plate glasses, and guides light emitted from the color foil 38. The relay lens 36 is configured by combining two lenses, and collects light while correcting axial chromatic aberration of light emitted from the light tunnel 37.

  The cylinder mirror 35 and the concave mirror 34 reflect the light emitted from the relay lens 36. The reflected light enters the image processing unit 32. The image processing unit 32 has a substantially rectangular mirror surface composed of a plurality of micromirrors, and each micromirror is based on video or image data. A DMD element that processes and reflects the projection light so as to form a predetermined image by being dividedly driven is provided. In the image processing unit 32, the light used by the plurality of micromirrors is reflected in the direction of the projection lens 51 indicated by the arrow B in the drawing, and the light to be discarded is the arrow C. It is reflected to the OFF light plate indicated by.

  FIG. 5 is a perspective view showing the configuration of the image processing unit 32. The image processing unit 32 includes a DMD element 41, a DMD printed circuit board 42 that controls the DMD element 41, a heat sink 43 that cools the DMD element 41, and a fixing plate 44 that presses the heat sink 43 against the DMD element 41. In the present embodiment, the heat sink 43 corresponds to a heat radiating portion. The heat sink 43 dissipates heat from the DMD element 41 by coming into contact with the DMD element 41 to be cooled first. FIG. 6 is a perspective view showing a detailed configuration of the projection optical unit 33. The light that has passed through the image processing unit 32 is reflected to the projection lens 51 in FIG. 6, and the light that is discarded is reflected to the off-light plate 53 in FIG.

  7 and 8 are a perspective view and a side view showing the configuration of the projection optical unit 33. FIG. The image light that has passed through the projection lens 51 and has been magnified has its optical path folded back by a folding mirror 54 and magnified and projected onto the screen 2 by a free-form curved mirror 55. With the above configuration, the optical engine unit 30 can be arranged close to the screen 2 and can be designed to be three-dimensionally compact because it is a vertical type whose optical axis path is vertical and has a small installation area.

  FIG. 9 is a diagram showing a configuration of the heat sink 43 used in the present embodiment. In the present embodiment, the heat sink 43 realizes a cooling structure for cooling the two devices of the image processing unit 32 and the light source device 20. The heat sink 43 is provided with a sirocco fan 61 inside (on the bottom side of the apparatus). The sirocco fan 61 corresponds to a blowing unit that takes in outside air to the heat sink 43 and blows air. The sirocco fan 61 has a structure in which a large number of small cylinders having forward-facing blades are combined with an air conditioner, and a general fan having a static pressure efficiency of about 60% is used.

  Moreover, the sirocco fan 61 has the 1st suction inlet 71, the 2nd suction inlet 72, and the discharge outlet 73, as shown in FIG. The second suction port 72 is provided on the opposite side of the first suction port 71, and the sirocco fan 61 is a double-sided suction fan. That is, in the present embodiment, the first suction port 71 is provided on the upper surface side of the sirocco fan 61, and the second suction port 72 is provided on the bottom surface side of the sirocco fan 61. Further, in this configuration, the sirocco fan 61 having the discharge port 73 having a wide discharge port 73, that is, a lateral width larger than the thickness is used, but this is for further improving the cooling efficiency. The sirocco fan 61 having a wider discharge port 73 can increase the area where the cooling air is discharged, and the contact area between the cooling air and the heat sink 43 can be increased. The cooling efficiency can be improved by increasing the contact area between the cooling air and the heat sink 43.

  FIG. 11 is a view of the flow of air discharged from the sirocco fan 61 as viewed from the bottom surface side of the sirocco fan 61. As shown in FIG. 11, the sirocco fan 61 is configured such that a large amount of air is concentrated on the end side indicated by the arrow in the outlet 73. Therefore, the flow rate of the cooling air to be discharged is not uniform, the first part where the air of the predetermined first flow rate flows and the flow rate is small, the second part where the air flows at the second flow rate higher than the first flow rate, It is possible to classify

  Of the cooling air generated by the sirocco fan 61, in the second region 43b having a high flow rate, the fin length of the heat sink 43 is increased to increase the surface area of the fin. Further, regarding the pitch of the fins, the pitch is made fine for the second region 43b through which the cooling air having a high flow rate passes, and the pitch is made coarse for the first region 43a through which the cooling air having a low flow rate passes. . The pitch is an interval between the fins.

  With such a structure, the surface area of the heat sink 43 in the second region 43b can be increased, and the cooling efficiency of the heat sink 43 is increased in the second region 43b through which a large amount of cooling air passes. Is possible. On the other hand, with respect to the first region 43a through which cooling air with a low flow rate passes, the ventilation resistance is reduced by roughening the pitch of the fins, and the cooling air that has passed through the first region 43a is downstream components. It shall be used for cooling. That is, the heat sink 43 is cooled in the second region 43b having a fine pitch and a long fin, and the downstream part is cooled in the first region 43a having a coarse pitch.

  Next, the positional relationship among the second cooling target light source device 20, the sirocco fan 61, and the heat sink 43 located on the downstream side of the air flow path in the heat sink 43 will be described with reference to FIG. 12. As shown in FIG. 12, the cooling duct 25 of the light source device 20 is connected in a straight line in the first region 43a having a large fin pitch. With such a configuration, the cooling air that has passed through the first region 43a enters the duct 25 without impairing the air volume, and the light source device 20 can be cooled. In this manner, the sirocco fan 61 and the heat sink 43 that are cooling sources for forced air cooling, and the light source device 20 that is the cooling target by the air that has passed through the heat sink 43 are arranged in a straight line in order. Further, by providing the cooling duct 25 for cooling the light source device 20 at a position facing the first region 43a having a rough pitch, the light source device 20 can be efficiently cooled in the first region 43a having a rough fin pitch. Can be done. On the other hand, the heat sink 43 is efficiently cooled in the second region 43b where the fin pitch is fine. Therefore, the two components of the heat sink 43 and the light source device 20 can be efficiently cooled by the single sirocco fan 61. As a method of guiding the cooling air after passing through the first region 43a without loss to the cooling duct 25 of the light source device 20, it is desirable to newly provide a connecting duct 62 as shown in FIG. .

  Next, the configuration of the image projection apparatus 1 that takes in such cooling air will be described. FIG. 14 is a perspective view of the image projection apparatus 1 as viewed from the installation surface side. As shown in FIG. 14, an opening / closing cover 84 is provided on the base 83 that forms the bottom surface of the image projection apparatus 1. The opening / closing cover 84 is provided with a rotation operation portion 84a. When the rotation operation unit 84a is rotated, the fixing of the opening / closing cover 84 and the apparatus main body is released, and the opening / closing cover 84 can be detached from the apparatus main body. An intake opening F2 is provided on the bottom surface of the base portion 83 of the image projection apparatus 1.

  FIG. 15 is an explanatory diagram for explaining the flow of air in the image projection apparatus 1 of the present embodiment. This figure is the figure which looked at the image projector 1 from the direction (X direction) orthogonal to the screen 2. As shown in FIG. In FIG. 15, the arrows in the figure indicate the direction of air flow. As shown in FIG. 15, an intake opening F <b> 2 that is opened to take in outside air into the image projection apparatus 1 is provided on one of the bottom surfaces of the image projection apparatus 1 (lower left portion in the figure). On the other side (upper right side in the figure), an exhaust opening 85 opened to exhaust the air in the image projection apparatus 1 is provided. An intake fan F1 is provided so as to face the intake opening F2. An exhaust fan 86 is provided so as to face the exhaust opening 85.

  For example, the intake fan F1 is a sirocco fan, and the exhaust fan 86 is an axial fan. Further, the intake fan F 1 and the intake opening F 2 are disposed in the vicinity of the heat sink 43. Compared with the air flow in the conventional image projection apparatus shown in FIG. 16, in FIG. 16, there is an intake opening F2 and an intake fan F1 on the side of the projector, and reaches the rear part of the light source 21 through the refracted duct path. On the other hand, in the image projection apparatus 1 of the present embodiment shown in FIG. 15, the air sucked by the intake fan F1 from the intake opening F2 passes through the linear duct 25 to the rear part of the light source 21 at a shorter distance than the prior art. To reach.

  Since the distance from the intake opening F2 to the rear portion of the light source 21 that is the cooling target is short and the duct 25 is linear, the pressure loss on the path from the intake fan F1 to the cooling target is reduced. be able to. Further, by making the intake fan F1 a double-sided intake sirocco fan, a forced air flow is generated near the cooling fins of the heat sink 43 by the intake of the sirocco fan on the opposite side of the intake opening F2 on the bottom surface, thereby cooling efficiently. can do.

  The heat sink 43 having a different pitch, which is an embodiment of the present invention, can be molded by either extrusion molding or die casting. Therefore, since it can be formed by the same processing method as a heat sink having a uniform pitch, it can be said that there is no need for special cost in processing the heat sink 43 shown in the present invention.

  As shown above, it is possible to simultaneously cool two or more parts with a single fan by using a configuration in which a cooling target is further arranged downstream of the heat sink 43 and at the same time by increasing the pitch of the fins. It becomes. As a result, the cooling efficiency is increased and the cooling device can be designed in a compact manner.

  Moreover, since the heat sink 43 is not a complicated shape, the above cooling effect can be obtained without increasing the cost. Therefore, it is possible to design a small and highly efficient cooling structure system while being inexpensive.

  Further, by arranging the intake opening F2 and the intake fan F1 on the bottom of the apparatus in the image projection apparatus 1, the arrangement of the light source device 20 and the heat sink 43 that are the objects to be cooled is close, and the air blows to the light source device 20 Therefore, the pressure loss in the duct is reduced, and the cooling efficiency of the light source device 20 is improved. As a result, the rotational speed of the intake fan F1 can be reduced, which leads to a reduction in apparatus noise. Further, by arranging the intake opening F2 and the intake fan F1 adjacent to the opening on the bottom of the apparatus, noise from the intake fan F1 is more easily attenuated from the side intake before reaching the user's ear, and sound propagation. Since the direction tends to diverge, it leads to noise reduction.

  The heat sink, the cooling device, and the cooling structure described above can be used not only for an image projection device but also for a device to be cooled by an electronic device such as a normal PC or an electronic circuit.

DESCRIPTION OF SYMBOLS 1 Image projection apparatus 2 Screen 3 Outer layer cover 20 Light source apparatus 21 Light source 22 Light source bracket 23 Outgoing window 24 Holder 25 Duct 30 Optical engine part 31 Illumination optical part 32 Image processing part 33 Projection optical part 34 Concave mirror 35 Cylinder mirror 36 Relay lens 37 Light tunnel 38 Color foil 41 DMD element 42 DMD printed circuit board 43 Heat sink 43a First region 43b Second region 44 Fixed plate 51 Projection lens 53 Off light plate 54 Folding mirror 55 Free curved surface mirror 61 Sirocco fan 62 Connecting duct 71 First suction port 72 2nd inlet port 73 Outlet port 83 Base part 84 Opening / closing cover 85 Exhaust opening 86 Exhaust fan F1 Intake fan F2 Intake opening

JP 2008-134432 A Japanese Patent No. 4901595 Japanese Patent No. 4927923

Claims (5)

A plurality of fins, the plurality of fins having at least a first region and a second region, wherein the second region has a smaller fin pitch than the first region;
A sirocco fan arranged so that more air flows in the second region than in the first region with respect to the heat sink;
Fi down of the heat sink, the at the end of the outlet side of the air flow resulting from the sirocco fan, a cooling device towards the fins of the second region than the fins of the first region and wherein the longer.   2. The cooling device according to claim 1, wherein the fins of the heat sink have linearly aligned end portions on the air inlet side generated from the sirocco fan. The cooling device according to claim 1 or 2 is fixed to the first cooling object, and the second cooling object is arranged downstream of the first region with respect to the air flow generated from the sirocco fan. Cooling structure. An image projection device comprising: an image display element for displaying an image; a projection optical unit for projecting the image displayed on the image display element; and a cooling structure according to claim 3 .
The first cooling object is the image display element;
The second cooling object is an image projection device that is a light source for illuminating the image display element. An electronic device comprising a cooling target and the cooling device according to claim 1 or 2 provided on the cooling target.

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