JP2014145879A - Electric element cooling configuration of projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-noise projector for cooling an electric element without reducing the cooling efficiency while keeping the fan rotation speed, because efficient cooling of a high-heat-generation IC cannot be performed and the cooling efficiency of the whole electric circuit board sometimes decreases in the conventional art.SOLUTION: The projection type display device includes: an electric circuit board on which a high-heat-generation integrated circuit is mounted; and a sheet metal that is disposed so as to face a fan for cooling the electric circuit board and the electric circuit board and grounds the electric circuit board. The sheet metal includes a heat receiving surface projecting at a position corresponding to the integrated circuit in the plane view, and includes a plurality of openings in a surface crossing the blowing direction of the fan, of continuous wall surfaces adjacent to the heat receiving surface.

Description

  The present invention relates to a cooling technique for an electric substrate inside a projection display device, and more particularly to a technique for cooling a high heat generation IC such as a semiconductor integrated circuit mounted on the electric substrate.

  Conventionally, in a projection display device such as a projector, image information is added to light emitted from a light source from a light modulation element and projected onto an external screen. Therefore, a ballast power supply board for driving a light source, a control board for processing a video signal from the outside and controlling a light modulation element, and a PFC for supplying power to these boards are provided in the projection display device. At least a power supply is arranged.

  In recent years, the progress of integration technology has led to the manufacture of small ICs with many integrated circuits. In addition, video signals input to a projection display device have been improved in definition and speed. Therefore, the heat density in the electric element that processes these electric signals is greatly increased.

  Therefore, in addition to cooling the entire electric circuit board by taking wind into the device and guiding the air around these electric circuit boards, especially for high heat generation ICs, a cooling structure dedicated to the electric elements is provided. It is common to have.

  In such a situation, for example, in Patent Document 1, bending or drawing is performed on a metal shield plate or heat receiving plate that sandwiches a substrate, and contact is made with a high-temperature heat generating IC mounted on an electric circuit substrate to be cooled. Let By adopting such a configuration, it is disclosed that a high temperature heat generating IC is cooled by using a metal plate (shield plate or heat receiving plate) as a heat radiating plate.

JP 2001-147061 A

  However, in the prior art disclosed in Patent Document 1 described above, the surface of the heat sink opposite to the surface facing the substrate has a concave shape in order to form a heat receiving surface to be brought into contact with the high heat generating IC. Therefore, on the back side of the heat receiving portion that comes into contact with the high heat generation IC, the cooling air stays in this portion, and the cooling efficiency for the high heat generation IC may be reduced. In addition, when it is bent and raised in a U-shape, the cross-sectional area connected to the heat radiating plate is remarkably reduced, so that heat resistance is generated at this portion, and efficient heat dissipation may be hindered.

  Further, the cooling air flow around the high temperature heat generating IC flows between the electric circuit board and the heat radiating plate in a shape for receiving heat from the high temperature heat generating IC (a convex shape obtained by bending or drawing a metal plate). May have been disturbed. For this reason, not only the high heat generation IC can be efficiently cooled but also the cooling efficiency of the entire electric circuit board may be lowered.

  Therefore, it is necessary to increase the number of fan rotations and cool the electric element, and there is a problem that the noise of the projector increases.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a highly efficient cooling configuration that can further improve the cooling efficiency of a high heat generating IC and can simultaneously cool an electric element mounted around the IC. .

  In order to achieve the above object, the present invention provides an electric circuit board on which a high-heat-generation integrated circuit is mounted, a fan for cooling the electric circuit board, and the electric circuit board. A sheet metal for grounding a substrate, wherein the sheet metal has a heat receiving surface protruding at a position corresponding to the integrated circuit in plan view, and is adjacent to the heat receiving surface. Among the wall surfaces, a plurality of openings are provided on a surface intersecting with the blowing direction of the fan.

  According to the present invention, it is possible to provide a highly efficient cooling configuration that can further improve the cooling efficiency of the high heat generating IC and can simultaneously cool the electric elements mounted around the IC.

The exploded perspective view explaining the 1st composition of the present invention Sectional drawing explaining the 1st structure of this invention The exploded perspective view explaining the other effect by the 1st composition of the present invention. Sectional drawing explaining the structure of 2nd Example of this invention Sectional drawing explaining the structure of 3rd Example of this invention Sectional drawing explaining the structure of 3rd Example of this invention Exploded perspective view illustrating the overall configuration of the projection display device

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a cooling configuration of an electric circuit board according to an embodiment of the present invention.

[Example 1]
FIG. 7 is an exploded perspective view for explaining the entire projector. 1 is a light source, 2 is an optical block that houses optical components that guide light from the light source 1, 3 is a projection lens that magnifies and projects light from the light source 1 onto an external screen, 4 is a power supply unit that houses a power supply board, and 5 A ballast substrate for driving the light source 1, a fan 6 for discharging heat generated inside the apparatus to the outside and cooling an electric circuit board to be described later, an electric circuit board for processing an input signal from the outside, and 8 The board case which earth | grounds the electric circuit board 7 is shown. The electric circuit board 7 is mounted with an IC (not shown) that performs high-speed arithmetic processing on a huge amount of information input from the outside. The substrate case 8 has an area equal to or larger than that of the electric circuit board 7 in order to reduce unnecessary radiation noise radiated from the electric circuit board 7, and is disposed opposite to the electric circuit board 7. Low, for example, aluminum or copper alloys are desirable.

  Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view in which members around the electric circuit board 7 are extracted and the electric circuit board 7 is floated from the board case 8. FIG. 2 is a cross-sectional view taken along line AA in FIG.

  In FIG. 1, a high heat generating IC 71 is mounted on the back surface of the electric circuit board 7 (not shown in FIG. 1). The substrate case 8 is formed with a convex portion 81 formed by drawing, for example, at a position facing the high heat generation IC 71, and a heat transfer member that can be flexibly deformed between the convex portion 81 and the high heat generation IC 71, for example, By disposing the heat conductive sheet 9, the high heat generating IC and the substrate case 8 are thermally coupled.

  Therefore, the heat generated from the high heat generation IC 71 is transferred to the substrate case 8 through the heat conductive sheet 9, is conducted on the substrate case, and is diffused to the low temperature side. Since the conducted heat is exhausted by the fan 6 to the outside of the apparatus, the substrate case 8 near the fan can always keep a low temperature with respect to the surroundings. As a result, the heat generated from the high heat generation IC is transported to the vicinity of the fan 6 and is cooled by the fan 6 to be exhausted to the outside of the apparatus.

  In such a configuration, the convex portion 81 is provided with a plurality of openings 82. Note that the opening 82 is disposed at a position where the air flowing in the vicinity of the high heat generating IC is not obstructed (having an opening on the surface intersecting the blowing direction). In particular, it is desirable to have openings on two surfaces that are orthogonal to the blowing direction when the projector is viewed in plan from the top surface (a surface parallel to the rotation axis of the fan 6). By doing in this way, as shown in FIG. 2, even on the back side of the convex portion 81 (the concave interior formed on the opposite side to the direction in which the electric circuit board 7 is disposed), air does not stay, It can be sufficiently used as a heat dissipation part. In cooling, as is well known, even in the case of heat transfer in a solid, the heat resistance increases in accordance with the heat transport distance, so exhaust heat in the vicinity of the heating element is ideal. From this point of view, providing the opening 82 at the position shown in FIG. 2 and allowing air to flow behind the convex portion 81 increases the cooling efficiency. Further, since the wind flow is induced even on the leeward side of the convex portion 81 by providing the opening 82, the wind flows over the entire area of the electric circuit board 7 as a result, thereby improving the overall cooling efficiency. It leads to. In addition, the convex portion 81 is physically separated from the substrate case 8 only at the opening 82, and everything else is connected to the substrate case 8, so that the heat transfer cross section is ensured. Therefore, a decrease in cooling efficiency can be minimized.

  Here, since the substrate case 8 has an effect of reducing unnecessary radiation noise from the electric circuit board 7 as described above, the opening 82 must be an opening that does not use unnecessary radiation noise as an antenna. The standard of unnecessary radiation noise is 1 GHz, and the regulation level is relaxed beyond that. Therefore, it is desirable that the opening 82 described in the present invention be a ridge line of 75 mm or less in which the ridge line of the opening is ¼ wavelength or less of 1 GHz. Further, for example, if the hole is a round hole, φ10 or less, and if the hole is a square hole, the total of the four sides is suppressed to 30 mm or less, so that radiation of unnecessary radiation noise can be sufficiently suppressed. In such an aperture, the frequency of noise radiated also differs depending on the frequency of the signal used in the electric circuit board. Absent.

  In such a heat dissipation configuration, when the projector is downsized, the light source 1 may be disposed below the substrate case 8. In such a case, the heat generated from the light source 1 is transferred to the adjacent substrate case 8, so that the high heat generation IC 71 to be cooled may be heated by the heat of the light source 1. As a result, the amount of heat transferred from the high heat generation IC 71 to the substrate case 8 decreases, and the cooling performance for the high heat generation IC 71 decreases. Therefore, as shown in FIG. 3, by arranging the opening 82 provided in the above-described convex portion 81 on the windward side with respect to the light source 1, heat transfer from the light source 1 to the high heat generation IC 71 is suppressed, and the high heat generation IC 71 is cooled. It becomes possible to reduce the decrease in efficiency. Also from such a meaning, when viewed from the direction B in FIG. 3, the straight line connecting the high heat generation IC 71 and the fan and the straight line connecting the high heat generation IC 71 and the light source substantially coincide with each other on the two surfaces intersecting the blowing direction. It is desirable to have an opening.

  With this configuration, the cooling efficiency of the entire substrate can be increased, and at the same time, unnecessary radiation noise can be reduced. Therefore, a low-noise projector can be realized without increasing the fan rotation speed more than necessary for cooling.

[Example 2]
Furthermore, as described above, FIG. 4 shows a configuration in which one side of the electric circuit board 7 and the board case 8 are arranged to face each other, and a board shield plate 10 is newly arranged to face the opposite side of the electric circuit board 7. Similar to the substrate case 8, a convex portion 101 is formed at a position facing the high heat generation IC 71, and heat transfer that can be flexibly deformed between the convex portion 101 and the substrate surface on the back side where the high heat generation IC 71 is mounted. By disposing a member, for example, a heat conductive sheet 91, the high heat generating IC 71 and the substrate shield plate 10 are thermally coupled. Then, the opening 102 is provided in the convex portion 101 as well as the convex portion 81. In addition, for the purpose of suppressing unnecessary radiation noise, the opening 102 also suppresses the radiation of unnecessary radiation noise by suppressing the total of four sides to 30 mm or less for a round hole, for example, φ10 or less. This is a more desirable shape.

  With this configuration, the heat generated from the high heat generation IC 71 is transferred to the pattern in the substrate and is transferred to the substrate shield plate 101 via the heat conductive sheet 91. Then, like the heat radiation in the substrate case 8, the heat is conducted on the substrate shield plate 101, diffused to the low temperature side, and finally exhausted to the outside air by the fan 6. That is, since heat can be radiated from the upper and lower sides of the high heat generating IC to the substrate case 8 and the substrate shield plate 10, the cooling efficiency can be further increased.

  As a result, the cooling efficiency of the entire substrate can be further increased, and at the same time, unnecessary radiation noise can be reduced. Therefore, a low-noise projector can be realized without increasing the fan rotation speed more than necessary for cooling.

[Example 3]
Next, the case where the radiator 11 is attached to the back side (concave side) of the convex portion 81 provided on the substrate case 8 to further increase the heat radiation efficiency from the substrate case 8 will be described with reference to FIGS. 5 and 6. 6 shows a view as seen from the direction C in FIG.

  The heat radiation from the substrate case 8 to the atmosphere is more efficient when the temperature difference between the two is larger. Therefore, in order to dissipate the heat of the high heat generating IC 71, it is desirable that the heat generating IC 71 be in the vicinity of the high heat generating IC. In addition, the heatsink requires a lot of space to be placed, so it is necessary to use the empty space in the above diagram to prevent the projector from becoming large. From these two points, it is desirable that the radiator 11 be thermally coupled to the back side (concave side) of the convex portion 81 via a heat conducting member (not shown).

  However, in this case, since the flow of the wind by the fan 6 is obstructed in the concave portion, the fin part 11a of the radiator can not be fully used, and only 11b may be used as the radiator. Therefore, as shown in FIG. 5 and FIG. 6, by providing openings 82 on two surfaces intersecting the blowing direction of the convex portion 81, it is possible to ventilate the entire fin region including 11 a that is a part of the radiator. Therefore, the performance of the radiator can be fully utilized.

  In addition, for the purpose of suppressing unnecessary radiation noise, the opening 102 also suppresses the radiation of unnecessary radiation noise by suppressing the total of four sides to 30 mm or less for a round hole, for example, φ10 or less. This is a more desirable shape.

  As a result, the cooling efficiency of the entire substrate can be further increased, and at the same time, unnecessary radiation noise can be reduced. Therefore, a low-noise projector can be realized without increasing the fan rotation speed more than necessary for cooling.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 1 Light source 2 Optical block 3 Projection lens 4 Power supply unit 5 Ballast board 6 Fan 7 Electric circuit board 8 Board case 81 Convex part 82 Opening 9 Thermal conduction sheet 9u Thermal conduction sheet 10 Substrate shield board 101 Convex part 102 Opening 11 Heat sink 11a Heat sink Board case convex part inside 11b Heat sink board case convex part outside

Claims (6)

An electric circuit board on which a high heat generation integrated circuit is mounted;
A fan for cooling the electric circuit board and a sheet metal disposed to face the electric circuit board and grounding the electric circuit board;
A projection display device comprising:
The sheet metal has a heat receiving surface protruding in a position corresponding to the integrated circuit in a plan view,
A projection display device comprising a plurality of openings in a surface that intersects with the blowing direction of the fan among continuous wall surfaces adjacent to the heat receiving surface. The projection display device according to claim 1,
The sheet metal is arranged to face the surface on which the integrated circuit is mounted,
The projection display device, wherein the heat receiving surface has a continuous wall surface adjacent to the heat receiving surface from the sheet metal, and has a shape protruding toward the integrated circuit. The projection display device according to claim 1,
It has a heatsink sheet that is thermally coupled to the electrical circuit board
The heat radiating metal plate is disposed to face the surface opposite to the surface on which the integrated circuit is mounted,
The heat-receiving surface has a continuous wall surface adjacent to the heat-receiving surface from the sheet metal, and has a shape protruding toward the back side of the substrate surface on which the integrated circuit is mounted. . The projection display device according to any one of claims 1 to 3,
The projection display device includes a light source,
A fan for exhausting heat from the light source;
A projection display apparatus, wherein the integrated circuit and the light source are arranged in this order from the windward side of the fan. The projection display device according to any one of claims 1 to 4,
The projection display device according to claim 1, wherein a plurality of openings each having a total ridgeline of 75 mm or less are provided. The projection display device according to any one of claims 1 to 5,
A projection display device, wherein a heat sink is thermally coupled to the inside of the convex shape.