JP2018101704A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device in which heat radiating efficiency of a heat generating portion is enhanced, while also enabling a usage method of being worn on the observer's head.SOLUTION: An electronic device includes: a heat generating portion that generates heat by electrical processing; a heat radiating plate radiating the heat of the heat generating portion; an exterior case formed with a plurality of holes which are opened substantially vertically to a surface of the radiating plate and which has a thermal conductivity lower than that of the radiating plate and covers the surface of the radiating plate.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an electronic device having a heat generating portion that generates heat by electrical processing.

  In recent years, an image display device (head mounted display = HMD) that is mounted on the head of an observer and displays an image in front of the eyes of the observer has been used. The HMD has advantages such as easy viewing of a video on a large screen and easy stereoscopic viewing. For these reasons, it is used as a device that can experience artificial reality (virtual reality = VR) and mixed reality (mixed reality = MR).

  An HMD for realizing MR has an imaging unit, a display unit for superimposing and displaying a captured image and a 3DCG image created by a PC, and an integrated circuit for performing various electrical processing and image processing. doing. In recent years, the processing capability of various integrated circuits has increased with the increase in image quality and wide angle of view of the imaging unit, and the power consumption has increased. As a result, the amount of heat generated from the integrated circuit is increasing. In an electronic device such as an HMD, when the temperature of the integrated circuit rises due to heat generation, there is a concern that the processing of the integrated circuit may malfunction, or the exterior temperature near the integrated circuit may rise locally. .

  In addition, the cooling means for generating noise and vibration such as FAN is difficult to employ because it causes discomfort to the observer due to the usage method of mounting on the head. Therefore, in such an electronic device, it is useful to use a heat radiating member to diffuse the heat of the integrated circuit throughout the device, or to dispose the heat radiating member in the path of the ventilation hole and cool the heat radiating member by natural convection. is there.

  For example, in Patent Document 1, a heat radiating hole is provided in the vicinity of two opposing sides of the bottom surface of the housing of the device, and the heat radiating plate in the convection path is cooled by sucking air from one hole and exhausting it from the other hole. It is disclosed.

JP 2011-141922 A

  However, since the heat dissipation structure described in Patent Document 1 uses natural convection, the heat dissipation efficiency largely depends on the area of the exhaust port, but the number and area of the exhaust ports provided are limited. Furthermore, there are few places where the heat sink directly hits the outside air, and heat tends to be trapped inside, that is, there is a possibility that the heat dissipation efficiency cannot be sufficiently increased.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic device with improved heat dissipation efficiency of a heat generating portion while enabling a usage method of mounting on an observer's head. To do.

  The present invention is an electronic device, and includes a heat generating portion that generates heat by electrical processing, a heat radiating plate that radiates heat from the heat generating portion, and a plurality of holes that are opened substantially perpendicularly to the surface of the heat radiating plate. And having a thermal conductivity lower than that of the heat radiating plate and covering the surface of the heat radiating plate.

  ADVANTAGE OF THE INVENTION According to this invention, the electronic device which improved the heat dissipation efficiency of the heat | fever of a heat-emitting part can be provided, enabling the usage method of mounting | wearing an observer's head.

1 is an external perspective view of a video display device according to a first embodiment. The disassembled perspective view of the display part of the video display apparatus in 1st Embodiment. The front view in the display part of the video display apparatus in 1st Embodiment Sectional view in the front view of FIG. Cross-sectional view showing the relationship between the hole diameter and depth and a graph showing the correlation External appearance perspective view of the display part in 2nd Embodiment FIG. 6 is a cross-sectional view broken away on the exterior hole 26a. External appearance perspective view of heat sink in 2nd Embodiment The longitudinal cross-sectional view shown by fracture | rupture on the exterior hole 33a in 3rd Embodiment The back view of the front exterior unit in a 3rd embodiment In the third embodiment, the figure shown by being broken on the exterior hole 43a The front view of the display part in 4th Embodiment

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an external perspective view of an HMD 1 according to an embodiment of the present invention. The HMD 1 is configured by combining a display unit 10 and a mounting unit 100 for mounting on a user's head. The user can fix the HMD 1 to the head by wrapping the wearing part 100 around the head and adjusting the belt length, and observe the image on the display unit 10 in front of the eyes.

(First embodiment)
Hereinafter, the heat dissipation structure of the HMD according to the first embodiment will be described with reference to FIGS. FIG. 2 is an exploded perspective view in which the front exterior 13 and the heat sink 11 are removed from the display unit 10. 3 is a front view of the display section 10, FIG. 4 is a cross-sectional view in FIG. FIG. FIG. 5 is a diagram and a graph showing the relationship between the hole size and depth.

  As shown in FIG. 2, a circuit board 14 is disposed inside the front exterior 13 and the heat radiating plate 11, and an integrated circuit 14 a is mounted at the center of the circuit board 14. In the integrated circuit 14a, various electrical processes such as processing of an image taken by the imaging unit and signal processing of an image displayed on a display element (not shown) are performed. For this reason, the power consumption of the integrated circuit 14a increases and a great deal of heat is generated. That is, the integrated circuit 14a becomes a heat generating part that generates heat. In order to diffuse and dissipate this heat, heat is transmitted to the heat sink 11. For the heat radiating plate 11, a metal such as copper or aluminum having a higher thermal conductivity than the front exterior 13 is used.

  The heat sink 11 is fixed to the front exterior 13 with a double-sided tape 12. The front exterior 13 is fixed to the rear exterior 19 with screws. The heat radiating plate 11 has a heat source contact portion 11a at the center, which is in contact with and thermally coupled to the heat conductive rubber 15 attached on the integrated circuit 14a of the circuit board. 4A, when the heat conductive rubber 15 is compressed and sandwiched between the integrated circuit 14a and the heat source contact portion 11a of the heat sink, the heat generated in the integrated circuit 14a is absorbed by the heat sink. 11 can be seen.

  A plurality of holes 13 a are formed in the front exterior 13 so as to open substantially perpendicular to the surface of the heat sink 11. From the longitudinal cross-sectional view of FIG. 4B, it can be seen that the heat radiating plate 11 is disposed on the back side of the front exterior 13 and that the heat radiating plate 11 is in contact with the outside air at the hole 13a. Thus, since the heat sink 11 is directly in contact with the low temperature outside air, the heat of the heat sink 11 can be efficiently radiated to the outside air. Further, as shown in FIG. 3, the heat exchange amount is increased by providing a large number of holes 13 a in the front exterior 13 and increasing the area where the heat radiating plate 11 contacts the outside air.

  Since the gap between the heat sink 11 and the front exterior 13 is large as shown in FIG. 4A immediately above the heat source contact portion 11a of the heat sink, there is a possibility that foreign matter may be mixed inside the display portion 10. Without a recess. In terms of appearance, it is difficult to distinguish between the hole 13a and the recessed portion 13b, and the uncomfortable feeling can be reduced as compared with the case where the recessed portion is not provided.

  In order to increase the heat dissipation efficiency, a large hole may be opened in the front exterior 13. However, when the user directly touches the heat dissipation plate 11, the heat dissipation plate 11 has high heat conductivity and may cause low temperature burns. is there. Therefore, in the present embodiment, a plurality of holes 13a having such a size that the user does not directly touch the heat radiating plate 11 are provided. Since a material such as a resin having a lower thermal conductivity than that of the heat sink 11 is used for the exterior, the temperature is lower than that of the heat sink 11 and low temperature burns are less likely to occur even when directly touched by the user. The size and depth of the exterior hole 13a where the user's finger does not touch the heat radiating plate 11 is such that the sphere 90 having the same size as a human finger is shown in the exterior hole 13a as shown in the cross-sectional view of FIG. The size and depth are set so that the sphere 90 and the heat sink 11 do not contact each other. Specifically, the diameter of the inscribed circle of the hole is 6 mm or less so that a small finger of a child does not enter, and the depth of the hole is 0.3 mm or more so that the skin does not reach the heat sink even if the finger is pressed against the hole. And

  Further, the size and depth of the holes have a correlation as shown in FIG. 5A and 5B are cross-sectional views when the sphere 90 is brought into contact with the opening of the hole. As shown in FIG. 5A, when the hole diameter is 6 mm, the depth must be deeper than 1.35 mm, but when the hole diameter is 3 mm, it should be deeper than 0.3 mm. This correlation is represented in a graph as shown in FIG. Because it depends on the curved surface shape of the exterior and the size of the ridgeline R of the opening of the hole, the depth cannot be generally determined as y or more when the inscribed circle diameter of the hole is x, but the graph of FIG. There is a correlation that the depth of the hole needs to be deeper as the diameter of the inscribed circle of the hole becomes larger.

(Second Embodiment)
Hereinafter, the heat dissipation structure of the HMD according to the second embodiment will be described with reference to FIGS. 6A and 6B are external perspective views of the display unit 10. FIG. 7A is a longitudinal sectional view broken on the hole 26a on the top surface exterior, and FIG. 7B is a cross section broken on the hole 23a on the front surface exterior. FIG. FIG. 8 is an external perspective view of the heat sink 21 in the present embodiment.

  As shown in FIG. 6, in the present embodiment, holes are provided in both side portions of the upper surface exterior 26 and the front exterior 23. Since no holes are provided in the front, the number of holes visible when the HMD is viewed from the front is small, and the appearance is good. Further, since the front portion of the display unit 10 is close to an integrated circuit that is a heat source, the temperature may become too high depending on power consumption. Therefore, heat is not actively radiated from the front portion of the display unit 10, but is radiated from the upper surface or side surface of the display unit 10 far from the heat source.

  As shown in the longitudinal sectional view of FIG. 7A, there is a gap between the heat radiating plate 21 and the front exterior 23, so that heat is not directly transferred. The heat radiating plate 21 and the upper surface exterior 26 are brought into contact with each other on the upper surface portion of the display unit 10, and the heat is radiated from the heat radiating plate 21 to the outside air through the holes 26 a of the upper surface exterior while radiating heat to the upper surface exterior. As shown in the cross-sectional view of FIG. 7B, the side surface of the display unit 10 has the same configuration. The heat sink 21 has a shape as shown in FIG. 8 and is fixed to the front exterior 23 with a double-sided tape 22. In order to prevent the heat of the heat radiating plate 21 from being transmitted to the front exterior through the double-sided tape 22, it is preferable to use the double-sided tape with as much thickness as possible while minimizing the number and area of the double-sided tape. By adopting such a configuration, it is possible to directly radiate heat from the heat radiating plate 21 to the outside air while preventing the exterior temperature of the front of the display unit from becoming locally high, and high heat radiation efficiency can be realized.

  In this embodiment, holes are provided in the exterior of the upper surface and both side surfaces of the display unit 10, but holes may be provided only on the upper surface, only both side surfaces, or only one side surface.

(Third embodiment)
The HMD heat dissipation structure according to the third embodiment will be described below with reference to FIGS. 9 to 11. FIG. 9 is a longitudinal sectional view broken on the hole 33a of the front exterior, and FIG. 10 is a rear view in a state where the elastic member 37 is attached to the front exterior 33. FIG. 11A is a longitudinal sectional view broken on the hole 33a of the front exterior, and FIG. 11B is a transverse sectional view broken on the hole 33a of the front exterior. As illustrated, the elastic member 37 is arranged on the outer peripheral portion of the hole 33a of the front exterior.

  In the present embodiment, as shown in FIG. 9, a rib 33 b having a constant height is provided on the back surface of the front exterior 33 so as to surround the hole 33 a. With this configuration, the depth of the hole 33a is defined by the rib 33b. The heat radiating plate 31 is in direct contact with the front outer casing 33 only at the ribs 33b around the holes, and is fixed to the front outer casing 33 by the double-sided tape 32 at the upper and lower bent end portions 31a and 31b. Compared with the first embodiment and the second embodiment, the area where the heat radiating plate 31 is in direct contact with the exterior is greatly reduced, so that an extreme temperature rise of the exterior can be prevented. Although the amount of heat radiation from the heat sink 31 to the exterior is reduced, the heat sink 31 is in direct contact with the outside air through the front exterior hole 33a, so heat exchange is performed between the heat sink 31 and the outside air, and high heat dissipation efficiency is achieved. Can be maintained.

  Further, in order to prevent foreign matters such as dust and dust from entering the inside of the display unit 10 from the hole 33a on the front exterior, an elastic member 37 is attached around the hole on the back of the front exterior. FIG. 10 shows a rear view of the front exterior 33 with the elastic member 37 attached. By enclosing a plurality of holes to a certain extent with one elastic member, the number of parts and the number of assembling steps can be reduced. The central portion of the front exterior is not a hole but a convex shape protruding to the back side, and there is no possibility of dust intrusion, so there is no need to surround it with an elastic member. The elastic member 37 may be fixed to the exterior with a double-sided tape processed into the same shape as the elastic member, or it is fixed by being hooked on a rib around the hole while pulling like rubber using the elasticity of the elastic member 37. Also good.

  By providing a rib around the exterior hole 33a, the depth of the hole becomes deeper, and the heat dissipation efficiency to the outside air decreases as the hole becomes deeper. As an improvement plan, as shown in FIG. 11, a gradient 43a is provided inside the hole 33a in the direction in which the hole 33a expands with respect to the exterior hole and the rib around the hole. As a result, compared with the case where there is no gradient as shown in FIG. 9, the air flow can be made smoother, and even when the hole is deepened, a decrease in heat dissipation efficiency can be suppressed. If the size of the hole is the same, deepening the hole makes it difficult for the user to touch the heat sink directly. Accordingly, the air flow may be improved and the heat dissipation efficiency may be increased by enlarging the holes or increasing the gradient. However, as shown in the cross-sectional view of FIG. 11 (b), the sphere 90 having the same size as a human finger is in contact with the opening end of the exterior hole, and the sphere does not contact the heat sink. It must be the depth, size, and gradient of the hole.

  In the configuration of the present embodiment, the heat dissipation efficiency from the heat sink to the outside air can be increased while preventing an extreme temperature rise of the exterior. Therefore, the power consumption of the integrated circuit is high, and the configurations of the first and second embodiments are effective when the exterior temperature becomes too high.

(Fourth embodiment)
Hereinafter, an HMD heat dissipation structure according to the fourth embodiment will be described with reference to FIG. 12A, 12 </ b> B, and 12 </ b> C are front views of the display unit 10.

  In the first embodiment and the third embodiment, a hole is provided in the front surface of the display unit 10. In the second embodiment, a hole is provided on the upper surface or side surface of the display unit 10. In terms of appearance, it is preferable to provide holes on the top and side surfaces where it is difficult to see the holes when viewed from the front. However, considering heat dissipation efficiency, it is better to provide holes on the front surface near the integrated circuit. Therefore, as shown in FIG. 12A, although the hole 53a is provided on the exterior front surface of the display unit 10, the hole shape is not a simple circle or square, but a cross hole and a round hole are combined to improve design. . By doing so, it is possible to achieve both high heat dissipation efficiency and good appearance quality.

  As shown in FIG. 12B, a honeycomb-shaped hole 63a may be provided for the purpose of ensuring the strength of the exterior and reducing the weight. The hole shape provided in the exterior is not limited to a circle, square, cross, or hexagon, and as described above, when the sphere 90 having the same size as a human finger is brought into contact with the end face of the exterior hole, it does not contact the heat sink. Any shape is acceptable. For example, an oblong hole 73a as shown in FIG.

  As described above, by bringing the heat sink into contact with the exterior and providing a hole in the exterior, the heat sink can come into contact with the outside air over a wide area, and high heat dissipation efficiency can be realized.

  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.

1 HMD (head mounted display)
DESCRIPTION OF SYMBOLS 10 Display part 11 Heat sink 13 Front exterior 13a Hole 13b Recessed part 14 Circuit board 14a Integrated circuit 15 Thermal conductive rubber 18 Imaging part 19 Back surface exterior 100 Mounting part

Claims (9)

A heating part that generates heat by electrical treatment;
A heat radiating plate for radiating heat of the heat generating portion;
A plurality of holes that are open substantially perpendicular to the surface of the heat radiating plate, have a lower thermal conductivity than the heat radiating plate, and have an exterior covering the surface of the heat radiating plate. Electronics.   The electronic apparatus according to claim 1, wherein the exterior and the heat radiating plate are thermally coupled.   The rib which prescribes | regulates the depth of these holes by enclosing these holes is provided between the said exterior and the said heat sink, The any one of Claim 1 or 2 characterized by the above-mentioned. The electronic device as described in the paragraph.   The electronic apparatus according to claim 1, wherein a gradient is formed inside the plurality of holes.   The plurality of holes have an inscribed circle having a diameter of 6 mm or less and a depth of the hole of 0.3 mm or more, and the correlation is such that the larger the diameter of the inscribed circle, the deeper the plurality of holes. The electronic device according to claim 1, wherein the electronic device is provided.   The electronic device according to claim 1, wherein an elastic member is disposed on an outer peripheral portion of the plurality of holes.   The electronic device according to claim 1, wherein the plurality of holes are a combination of a cross hole and a round hole.   The electronic device according to claim 1, wherein the plurality of holes are honeycomb-shaped holes.   The electronic apparatus according to claim 1, further comprising a mounting portion for mounting on a user's head.

Images