JP5983095B2 - Display device - Google Patents

Description

  The present invention relates to a display device using a good heat conductive material for a mounting portion of a case in which a display unit is accommodated.

  FIG. 3 is a cross-sectional view of a liquid crystal display device using liquid crystal as a display element. The liquid crystal display device includes a liquid crystal display unit 1 and a case 2 in which the liquid crystal display unit 1 is accommodated. The liquid crystal display unit 1 includes a liquid crystal display element 3 called a TFT type, and the liquid crystal display element. 3, a liquid crystal display element 3 and a synthetic resin holder 5 that holds the backlight device 4, and a metal that fixes the liquid crystal display element 3 and the backlight device 4 to the holder 5. A holding frame 6, a circuit board 8 mounted behind the holder 5 on which an electronic component 7 for driving the liquid crystal display element 3 and lighting a light source to be described later is mounted, a shield case 9 made of steel, and the like. . Although not shown, the liquid crystal display element 3 and the circuit board 8 are electrically connected.

  The backlight device 4 includes a cold-cathode tube 10 as a light source, a colorless and transparent light guide member 11 that guides light from the cold-cathode tube 10 incident inside from the end face to the back side of the liquid crystal display element 3, and the light guide. It consists of a reflection plate 12 disposed behind the member 11 and an optical sheet 13 such as a diffusion sheet or a prism sheet disposed between the liquid crystal display element 3 and the light guide member 11. The backlight device 4 illuminates the liquid crystal display element 3 from behind so that the display (for example, in the case of a liquid crystal display device for a vehicle, the remaining amount of fuel, temperature, message, etc.) can be seen well.

  Further, the liquid crystal display unit 1 includes a hard main substrate 14 and a synthetic resin frame 15. Each component described above is housed in the frame 15, and although not shown in detail, it is unitized by fixing the main board 14 to the frame 15. The main board 14 is mounted with an electronic component 7A for a power supply circuit of the liquid crystal display device, a circuit for sending display data to the liquid crystal display element 3, and the like.

The case 2 is composed of a divided upper case 2A and lower case 2B. The upper case 2A has a window portion 16 made of a colorless and transparent synthetic resin and a cover portion 17 made of an impermeable (for example, black) synthetic resin. Are integrally formed. The cover part 17 includes a front part 18 and a side part 19. Further, a substantially cylindrical upper mounting boss 20 is integrally provided on the front portion 18 of the upper case 2A.
The lower case 2B is made of an impermeable synthetic resin like the upper case 2A, and has a bottom portion 21 and a side portion 19A. The lower case 2B is provided with a lower mounting boss 22 for the lower case 2B projecting from the bottom 21 corresponding to the upper mounting boss 20 provided on the upper case 2A. It has become a shape.

  In the liquid crystal display unit 1, an aluminum heat sink 30 is disposed behind the shield case 9 via a heat dissipating sheet 31 made of silicone rubber. The heat dissipation sheet 31 is disposed so as to be sandwiched between the shield case 9 and the heat dissipation plate 30.

Japanese Patent No. 3896593

  However, in the liquid crystal display device described above, heat generated from the cold cathode fluorescent lamp 10, the electronic components 7 and 7 A mounted on the circuit board 8 and the main board 14 (particularly when the light source is the cold cathode fluorescent lamp 10) The temperature in the case 2 rises due to the high heat generation from the transformer, which is an inverter circuit component that turns on the display, and display may be difficult to see, such as display unevenness in the liquid crystal display element 3. In addition, when the liquid crystal display device is installed in a motorcycle or an agricultural machine that is exposed to the outside, it is not possible to provide the case 2 with an air passage that communicates the inside and outside of the case 2 because of the necessity of waterproofing and dustproofing. Further, as described above, since no gap is formed between the upper case 2A and the lower case 2B, such a tendency is stronger.

  Therefore, the heat radiating plate 30 made of aluminum is arranged behind the shield case 9 via the heat radiating sheet 31 made of silicone rubber, so that the heat released from the display unit is transferred to the heat radiating sheet 31 and the heat radiating plate 30. However, there is a problem that the structure becomes complicated and the cost becomes high.

  The present invention has been made in view of the above points, and provides a display device with good visibility by dissipating heat inside the case in which the display unit is housed to the outside of the case as much as possible without using a heat sink. The purpose is to do.

  In order to achieve the above object, the present invention includes a case and a display unit including a circuit board housed in the case. A mounting portion is integrally formed in the case, and the mounting portion and the actual machine part are provided. A display device fixed by a fixing means, wherein the circuit board has a through hole through which the mounting portion passes, and the mounting portion is made of a good heat conductive material, and an elastic member is provided on a back surface side of the display unit. It is provided.

The heat conductive material is aluminum or copper.

  The elastic member is made of a heat conductive member, and transfers heat released from the display unit to the mounting portion.

  Further, the heat radiated from the display unit is dissipated from the mounting portion.

  The heat dissipated from the display unit is dissipated from the case.

  Since the heat trapped in the case is transmitted to the outside of the case through the mounting portion made of a good heat conducting material, a display device with good visibility can be obtained while suppressing the temperature rise of the display element.

  Although an example in which the present invention is applied to a liquid crystal display device for a vehicle will be described as an embodiment, the same or corresponding portions are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 is a cross-sectional view of a liquid crystal display device, and FIG. 2 is a partial detail view showing an insert-molded mounting portion.

  The case 2 is composed of a divided upper case 2A and lower case 2B. The lower case 2B has a mounting boss (mounting portion) 22a projecting from the bottom 21 and a cross section in which the bottom 21 side is opened. It is substantially cylindrical.

  The mounting boss 22a of the lower case 2B in the present embodiment is made of aluminum or copper, which is a material with good thermal conductivity. The mounting boss 22a has a substantially cylindrical shape having a peripheral wall 25 and a bottom wall 27 provided with a through hole 26, and is integrally formed with the lower case 2B by a technique such as insert molding in a state where the bottom 21 side of the lower case 2B is opened. ing.

  In this embodiment, the holder 5 is formed of a resinous material and is cut out so as to avoid a heat transfer sheet (elastic member) 31 disposed on the back surface of the light guide member 11 on the back surface side of the liquid crystal display element 3. A part 51 is provided.

  The heat transfer sheet 31 in the present embodiment is made of, for example, a graphite sheet made of a conductive member, and is in contact with the mounting boss 22a so that the heat of the liquid crystal display element 3 is transferred to the mounting boss 22a via the heat transfer sheet 31. Is arranged. By making the heat transfer sheet 31 conductive, the antistatic performance of the liquid crystal display unit 1 can be improved.

  When assembled, the circuit board 8 is provided with a through hole 81 through which an opening portion of the bottom 21 of the lower case 2B and a mounting boss 22a formed integrally with the lower case 2B pass.

  The liquid crystal display unit 1 is assembled to the case 2 in the same manner as in the conventional example. However, in the present embodiment, the heat transfer sheet 31 is disposed between the liquid crystal display unit 1 and the mounting portion 22a, and the actual component 100 is provided. In a state of being sandwiched, the screw 24 is inserted into the opening space of the mounting boss 22a and tightened to the mounting boss 22a.

  In this way, the mounting boss 22a provided for fixing the lower case 2B and the actual machine component 100 is made of a material having good thermal conductivity, so that the heat generated from the liquid crystal display unit 1 and the electronic components 7 and 7A can be obtained. The heat generated in the case 2 and so on is transmitted to the peripheral wall 25 and the bottom portion 27 of the mounting boss 22a and diffused to the outside of the lower case 2B. The heat dissipated from the lower case 2 </ b> B is transmitted to the actual machine part 100 and is dissipated outside the actual machine part 100.

  In addition, a part of the heat transmitted to the mounting boss 22a is also transmitted to the bottom 21 of the lower case 2B, so that a heat radiation effect can be expected in a wide range of the actual machine part 100, and a heat sink is provided while maintaining waterproof and dustproof properties. In addition, it is possible to provide a liquid crystal display device with good visibility by suppressing the temperature rise of the liquid crystal display element 3.

  Further, since the mounting boss 22a made of a good heat conductive material is integrally formed with the lower case 2B, the number of components of the lower case 2B can be reduced, and the assembly workability of the liquid crystal display device can be facilitated.

  In this embodiment, the heat transfer sheet is made conductive. However, the heat transfer sheet may be made of synthetic resin having flexibility, and in the case of insulation, a silicone rubber sheet or the like is suitable.

  In the above-described embodiment, the screw 24 is used as a fixing means for fixing the lower case 2B and the actual machine part. However, the screw 24 is not limited thereto. Moreover, although the mounting boss 22a made of a good heat conductive material is integrally formed with the lower case 2B, it may be a separate body (may be separable).

  Further, the liquid crystal display device in which the liquid crystal display unit 1 is accommodated in the case 2 has been described as an embodiment. However, in the case 2, an analog speedometer, tachometer, and the like are accommodated in addition to the liquid crystal display unit 1. May be. Further, a display element other than the liquid crystal, for example, a fluorescent display tube may be used. When a liquid crystal display unit is used, a circuit board on which at least a liquid crystal display element, a light source (not limited to the cold cathode tube 10) for illuminating the liquid crystal display element, and electronic components for displaying the liquid crystal display element are mounted. It only has to be prepared.

1 is a cross-sectional view of a liquid crystal display device showing an embodiment of the present invention. The partial detail figure which shows the attaching part of the liquid crystal display device. Sectional drawing of the liquid crystal display device which shows a prior art example.

1 Liquid crystal display unit (display unit)
2 Case 2B Lower case 22a Mounting boss (mounting part)
24 screws (fixing means)
31 Heat transfer sheet (elastic member)
100 Real machine parts

Claims (5)

A case and a display unit including a circuit board and housed in the case;
A display device in which a mounting portion is integrally formed with the case, and the mounting portion and an actual machine part are fixed by a fixing means,
The circuit board has a through hole through which the attachment portion passes,
The display device is characterized in that the attachment portion is made of a heat conductive material and is provided on the back side of the display unit via an elastic member. The display device according to claim 1, wherein the heat conductive material is aluminum or copper.   The display device according to claim 1, wherein the elastic member is made of a heat conductive member, and conducts heat released from the display unit to the mounting portion. The heat released from the display unit, the display device according to claims 1 to 3, characterized in that it is dissipated from the mounting portion. The heat released from the display unit, the display device according to any one of the four claims 1, characterized in that is dissipated from the casing.

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