JP5932297B2 - Display device - Google Patents

Description

The present invention relates to a heat dissipation structure for a display device .

In a display device using a backlight, a heat dissipation measure is taken in order to discharge heat generated in the drive circuit unit of the light source to the outside of the device.
A conventional liquid crystal display device includes a direct-type backlight device on the back surface of a liquid crystal panel, and a peripheral portion of the liquid crystal panel is covered with a metal frame from the display surface side. On the back side of the liquid crystal panel, a support member for supporting the peripheral edge of the panel is provided, and a backlight case formed in a box shape is further disposed. A liquid crystal driver IC that drives the liquid crystal panel is mounted on an FPC (Flexible Printed Circuit) that connects the liquid crystal panel and the drive circuit board, and the heat generated by the IC is transferred to the metal frame of the outer frame to be inside the casing. Discharged into the space. A natural air cooling type or a forced air cooling type heat dissipation structure using a cooling fan or the like is adopted.
In recent years, liquid crystal display devices have been used in the case of viewing the frame width, which is a non-display area around the display screen, that is, the exterior frame, when viewed from the front, in response to requests for use in a limited space or improvements in design. It is required to make the frame width as narrow as possible. For this reason, a structure in which a metal frame is also used as an exterior frame has been proposed. On the other hand, the amount of heat generation tends to increase with the increase in size and definition of the liquid crystal panel and the increase in the density of the liquid crystal driver IC. Therefore, in order to keep the temperature rise within the guaranteed operating temperature, it is necessary to devise a further heat dissipation structure. Patent Document 1 discloses a heat dissipation technique that transfers heat generated by the liquid crystal driver IC to a frame that also serves as an exterior frame via a heat conductive member.

Japanese Patent Laid-Open No. 2007-222068

However, as in the prior art disclosed in Patent Document 1, there is the following problem in the configuration in which the heat of the liquid crystal driver IC is transmitted to the frame that also serves as the exterior frame.
If the temperature of the metal exterior member rises to around a standard temperature value (for example, 70 ° C), or if the user accidentally touches the exterior member even if the temperature is below the standard temperature value, there is a possibility of discomfort was there. In addition, along with the increase in size and definition of the liquid crystal panel and the increase in the density of the liquid crystal driver IC, a further heat dissipation structure for preventing overheating of the liquid crystal driver IC is required.
Accordingly, an object of the present invention is to prevent overheating of the drive circuit portion of the display panel while suppressing the temperature rise of the exterior frame.

In order to solve the above problems, an apparatus according to the present invention includes a display panel, a frame that supports a peripheral portion of the display panel from the front side, a drive circuit that drives the display panel, and light from the back side to the display panel. A case member containing a light source that irradiates the display panel, and a support member that supports the peripheral portion of the display panel from the back side. The support member has a through-hole, and the drive circuit is disposed in the through-hole. is bound to said casing member through a first heat conducting member being, and characterized in that it bound to the frame via a second heat conduction member.

  ADVANTAGE OF THE INVENTION According to this invention, overheating of the drive circuit part of a display panel can be prevented, suppressing the temperature rise of an exterior frame.

It is sectional drawing which shows the structural example of the display apparatus which concerns on 1st Embodiment of this invention combined with FIG. It is sectional drawing which shows the structural example of the display apparatus which concerns on the modification of 1st Embodiment. It is a figure which illustrates typically the section of a thermal analysis model. It is a graph which illustrates the thermal analysis result of each part. It is sectional drawing which shows the structural example of the display apparatus which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[First Embodiment]
A display device according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 is a partial cross-sectional view of a liquid crystal display device 100 having a direct type backlight device. Below, the display surface side of the liquid crystal panel 105 is defined as the upper side, and the non-display surface (back surface) side is defined as the lower side, and the positional relationship between the respective parts will be described.
FIG. 1 shows an upper frame 106 that supports the peripheral edge of the liquid crystal panel 105 from the display surface side, a lower holder 107 that supports the liquid crystal panel 105 from the back side, and a backlight case (hereinafter referred to as a BL case) that houses a light source unit. 109). A control board 102 that generates a control signal for the liquid crystal driver IC 101 is disposed behind the BL case 109, and a drive circuit board 103 that distributes the signal to the liquid crystal driver IC 101 is formed between the upper frame 106 and the lower holder 107. Located in the space. A liquid crystal driver IC 101 is mounted on the FPC 104 that connects the liquid crystal panel 105 and the drive circuit board 103.

  First, the support structure of the liquid crystal panel 105 will be described. The upper frame 106 is provided as a frame-shaped frame member that covers the peripheral edge portion from the display surface side. The peripheral edge of the liquid crystal panel 105 is held by the lower holder 107 from the back side. An elastic member 106 a is disposed between the upper frame 106 and the liquid crystal panel 105, and an elastic member 107 a is disposed between the liquid crystal panel 105 and the lower holder 107. These elastic members are close to or in contact with the liquid crystal panel 105 so that local stress is not applied to the liquid crystal panel 105. Regarding the elastic modulus, which is a physical property value representing the difficulty of deformation, a material in which the elastic member 107a is larger than the elastic member 106a is used. As a result, it is possible to prevent the liquid crystal panel 105 from being held in place and to prevent foreign matters such as dust from entering while releasing local stress. As the elastic modulus values, the elastic member 106a has an Asker C hardness of about 10 to 30, and the elastic member 107a has an Asker C hardness of about 30 to 50. In addition, Asker C is one of durometers (spring type hardness meter) defined in SRIS0101 (Japan Rubber Association Standard). If it is described as 20 in Asker C, it indicates that the value measured by the Asker C hardness tester is 20. For the elastic members 106a and 107a, a material having a compressive residual strain of about 3% is used so that the thickness of the member does not easily change due to aging.

  The lower holder 107 serves as a support member that supports the peripheral edge of the liquid crystal panel 105 from below, and holds the optical sheet group 108 of a direct-type backlight light source (hereinafter simply referred to as a light source) 110 from above to drive a circuit board. 103 is held. A light emitting diode or the like is used for the light source 110 that irradiates the liquid crystal panel 105 with light from the back side, and the optical sheet group 108 includes a sheet member that diffuses light, a sheet member that improves luminance, and the like. The lower holder 107 is made of an ABS resin or a polymer alloy resin such as ABS and PC (polycarbonate) in consideration of electrical insulation and a cross-sectional shape thereof. A BL case 109 constituting a backlight device is located inside the lower holder 107, and is formed in a substantially box shape by press working using a metal plate material. The light source 110 is disposed on the inner bottom surface of the BL case 109 in a space formed by closing the opening of the BL case 109 with the optical sheet group 108. A heat radiator 111 is attached to the back surface of the BL case 109 in order to transmit heat generated by the light source 110 to a space inside the housing of the liquid crystal display device 100.

In the liquid crystal display device 100 according to the present embodiment, the liquid crystal driver IC 101 is thermally radiated by being thermally bonded to the metal BL case 109. Furthermore, in order to reduce the contact thermal resistance between the liquid crystal driver IC 101 and the BL case 109, it is preferable that the liquid crystal driver IC 101 and the BL case 109 are thermally bonded via the heat conducting member 112. FIG. 1 shows an example in which a heat conducting member 112 is provided in a through portion 107 b formed in the lower holder 107. It is preferable that the heat conducting member 112 does not apply a mechanical load to the liquid crystal driver IC 101 and the FPC 104 while sufficiently dissipating heat from the liquid crystal driver IC 101. Therefore, a flexible material having a thermal conductivity of about 1 to 6 (W / m · K) and an Asker C hardness of about 10 is used. Furthermore, it is preferable to use a material such as an acrylic base material that does not contain siloxane. This is to prevent the generation of a low molecular siloxane gas that causes a failure to the electronic circuit.

Hereinafter, the assembly order of the liquid crystal display device 100 will be described.
First, the operator puts the optical sheet group 108 on the BL case 109 containing the light source 110, and then considers thermal expansion and contraction of the optical sheet group 108 with the lower holder 107 to about 0.5 mm. It is clamped with a clearance. Thereby, a light diffusing space having a substantially sealed structure including the BL case 109 and the optical sheet group 108 is formed. Next, the operator places the liquid crystal panel 105 on the lower holder 107 with the optical sheet group 108 facing down. The liquid crystal driver IC 101 on the FPC 104 extended from the glass end portion of the liquid crystal panel 105 is in close contact with the heat conducting member 112 and assembled in a positional relationship in which it is thermally coupled to the BL case 109.
Since the heat conducting member 112 is disposed in the through portion 107 b facing the liquid crystal driver IC 101 in the lower holder 107, the heat generated by the liquid crystal driver IC 101 is transmitted from the heat conducting member 112 to the BL case 109. The through portion 107 b is a notch formed by notching a hole formed in the lower holder 107 or a part of the lower holder 107. The heat conducting member 112 is bonded to the position facing the liquid crystal driver IC 101 on the outer surface of the metal BL case 109 with a double-sided tape or the like.
As described above, in the present embodiment, the amount of heat transmitted to the upper frame 106 can be reduced by providing the heat conducting member 112 between the liquid crystal driver IC 101 and the BL case 109. As a result, the liquid crystal driver IC 101 can dissipate heat while suppressing an increase in the temperature of the upper frame 106 that also serves as an exterior frame.

  FIG. 2 shows a modification of the first embodiment. In addition to the configuration of FIG. 1, a heat conducting member 201 is also provided on the upper frame 106 opposite to the BL case 109. Since the heat of the liquid crystal driver IC 101 is also transmitted to the upper frame 106 via the heat conducting member 201, the temperature of the upper frame 106 rises compared to the configuration of FIG. However, with respect to the rising temperature value of the liquid crystal driver IC 101, the heat dissipation amount increases because the heat dissipation path has two upper and lower paths. As a result, the elevated temperature value can be reduced as compared with the configuration of FIG.

Next, the results of thermal analysis when the display device according to this embodiment is schematically described will be described with reference to FIGS.
FIG. 3 is a sectional view showing an analysis model related to the heat dissipation structure of the liquid crystal display device 400. FIG. 3 shows a liquid crystal driver IC 401, a heat conduction member 402 on the upper side of the figure, an upper frame 403, a heat conduction member 404 on the lower side of the figure, a BL case 405, a heat sink 406, and a light source 407. In addition, a heat dissipation space 408 that is sufficiently large with respect to the size of the liquid crystal display device 400 is provided, and analysis is performed in consideration of heat conduction, heat convection, and heat radiation. A liquid crystal driver IC 401 and a plurality of light sources 407 are assumed as heat generating components, and the respective heat generation amounts are given as 0.8 (W / piece) and 0.17 (W / piece). For the components shown above, the mutual contact thermal resistance is ignored in the analysis, and the result is derived.

Table 1 below shows analysis condition values for performing thermal analysis of the liquid crystal display device 400, and the ambient temperature (ambient temperature) was set to 25 ° C.

本例では上フレーム４０３、液晶ドライバＩＣ４０１、ＢＬケース４０５の温度を熱解析により求めた結果を示す。解析パラメータについては、放熱板４０６に対する拘束条件の温度を４０°Ｃ、５０°Ｃ、６０°Ｃとして解析を行った。 Table 2 below shows the temperature of each part when the heat conducting member is provided at the position shown below.
(I) When the heat conducting member 402 is disposed between the liquid crystal driver IC 401 and the upper frame 403 (see the upward triangle)
(II) When the heat conducting member 404 is disposed between the liquid crystal driver IC 401 and the BL case 405 (see the downward triangle)
(III) When the heat conducting member 402 is disposed between the liquid crystal driver IC 401 and the upper frame 403, and the heat conducting member 404 is disposed between the liquid crystal driver IC 401 and the BL case 405 (see square marks).

In this example, the results of obtaining the temperatures of the upper frame 403, the liquid crystal driver IC 401, and the BL case 405 by thermal analysis are shown. Regarding the analysis parameters, the analysis was performed with the temperature of the constraint condition for the heat sink 406 being 40 ° C, 50 ° C, and 60 ° C.

FIG. 4 illustrates the result of thermal analysis.
In FIG. 4A, the horizontal axis indicates the restraint temperature of the heat radiating plate 406, and the vertical axis indicates the analysis temperature of the upper frame 403. The graph lines in the case of (II) (see downward triangle mark) and in the case of (III) (see square mark) are shown by solid lines. As a comparative example, a graph line in the case of the conventional structure adopting the above (I) (see the upward triangle mark) is shown by a broken line.
In FIG. 4B, the horizontal axis indicates the restraint temperature of the heat sink 406, and the vertical axis indicates the analysis temperature of the liquid crystal driver IC 401. The meanings of triangle marks and square marks, and solid and broken graph lines are the same as those in FIG. Although not shown in the graph, from the results shown in Table 2 above, the analysis temperature of the BL case 405 was almost equal to the restraining temperature of the heat sink 406.
First, paying attention to the difference in the analysis temperature depending on the arrangement position of the heat conducting member, as shown in FIG. .
・ In the case of (I): 56.7 ° C
・ In the case of (II): 42.2 ° C
・ In the case of (III): 50.2 ° C
The temperature of the upper frame 403 is lowest when the heat conducting member 404 is installed only between the liquid crystal driver IC 401 and the BL case 405. This is because the heat of the liquid crystal driver IC 401 is transmitted to the BL case 405 almost.

On the other hand, the analysis temperature of the liquid crystal driver IC 401 when the heat sink 406 has a restraint temperature of 50 ° C. is as follows.
・ In the case of the above (I): 81.9 ° C
・ In the case of (II): 78.2 ° C
・ In the case of (III): 64.3 ° C
The temperature of the liquid crystal driver IC 401 is lowest when the heat conducting members 402 and 404 are arranged on both sides thereof. This is because the heat of the liquid crystal driver IC 401 is transmitted to both the upper frame 403 and the BL case 405.
From the above analysis results, it can be seen that the temperature rise values of the liquid crystal driver IC 401 and the upper frame 403 can be reduced as compared with the conventional structure if the temperature of the heat sink 406 is kept below a predetermined value. It has been found that the temperature of the heat radiating plate 406 for effectively applying this embodiment should be kept below 60 ° C. from the analysis result of FIG.
According to the first embodiment, the temperature of the exterior frame is increased by thermally connecting the driving circuit unit of the liquid crystal panel and the BL case member to form a heat transfer path from the driving circuit unit to the BL case member. It is possible to prevent overheating of the drive circuit portion of the display panel while suppressing the above.

[Second Embodiment]
Next, a display device according to a second embodiment of the present invention will be described with reference to FIG. In the liquid crystal display device 600 according to the second embodiment, the same reference numerals are used for the same components as those in the first embodiment, and detailed descriptions thereof are omitted.
The BL case 601 behind the liquid crystal panel 105 not only makes the light of the light source 110 uniform in the light diffusion space, but also plays a role of maintaining the rigidity of the liquid crystal display device 600. The metal BL case 601 is folded so that the peripheral portion has a U-shaped cross-sectional shape. That is, the side surface portion has a shape that is folded back to the right in FIG. 5, and the folded portion 601 b is formed with a through portion 601 a at a location facing the liquid crystal driver IC 101. A heat conducting member 604 is disposed in the through portion 601a, and the liquid crystal driver IC 101 and the radiator 602 are coupled to each other through the member. The radiator 602 is attached to the side opposite to the surface where the portion is in close contact with the lower holder 107 in the space formed by the folded portion 601b. The heat generated by the liquid crystal driver IC 101 is transmitted to the radiator 602 through the heat conducting member 604 and is discharged from the radiator 602 to the space inside the housing. The air radiated into the housing is quickly discharged outside the housing using forced air cooling means (not shown) such as natural air cooling or a fan.

  As shown in the analysis results of FIGS. 4A and 4B, the temperature reduction effect of the liquid crystal driver IC 101 and the upper frame 106 could be confirmed by lowering the temperature of the heat sink and the BL case. Therefore, in the second embodiment, the heat radiator 603 is used as the first heat radiating means for the heat radiation of the light source 110, and the heat radiator 602 is used as the second heat radiating means for the heat radiation of the liquid crystal driver IC 101. As described above, since the heat dissipating members are separately provided for the respective heat generation sources, it is possible to realize a heat dissipating structure that prevents the liquid crystal driver IC from being overheated while suppressing the temperature rise of the upper frame that also serves as the exterior frame.

100, 200, 400, 600 Liquid crystal display device 101, 401 Liquid crystal driver IC
105 Liquid crystal panel 106, 403 Upper frame 107 Lower holder 107b Through part 109,405,601 BL case 110,407 Light source 111 Radiator 112,201,402,404,604 Thermal conduction member 601a Through part 602,603 Heat radiator

Claims (5)

A display panel;
A frame that supports the peripheral edge of the display panel from the front side;
A drive circuit for driving the display panel;
A case member containing a light source for irradiating light from the back to the display panel;
A support member that supports the peripheral portion of the display panel from the back side;
The support member has a penetrating portion;
The drive circuit is coupled to the case member via a first heat conducting member disposed in the penetrating portion , and is coupled to the frame via a second heat conducting member. Display device. The display device according to claim 1, wherein the penetrating portion is a notch formed by notching a hole formed in the support member or a part of the support member .   The display device according to claim 1, wherein a heat radiating unit is provided on the back side of the case member opposite to the light source. A display panel;
A frame that supports the peripheral edge of the display panel from the front side;
A drive circuit for driving the display panel;
A case member containing a light source for irradiating light from the back to the display panel;
The case member has a folded portion, which is folded at the peripheral portion of the case member so as to form a U-shaped cross-sectional shape when viewed from the side surface side.
The display device, wherein the drive circuit is coupled to a heat radiating means provided in the folded portion via a heat conducting member. A support member for supporting the peripheral edge of the display panel from the back side;
A first penetrating portion provided in the folded portion;
A second penetrating portion provided in the support member,
The display device according to claim 4, wherein the heat conducting member is disposed so as to penetrate the first penetrating portion and the second penetrating portion.

Images