JP2008216406A - Heat radiation structure and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat radiation structure that radiates heat generated by a white LED in trade-off relation while employing the white LED for a liquid crystal back light to actualize high luminance and simple constitution. <P>SOLUTION: A heat radiation plate 17 which absorbs and radiates the heat generated by the white LED used for the back light of a liquid crystal panel has a base portion A supporting the whole heat radiation plate, a heat absorption portion B in thermal contact with the white LED, a swelled portion C swelled from the base portion, and a support portion D formed from hopping up from the swelled portion and supported by a housing of a liquid crystal display device, those portions being formed out of sheet metal in one body. Consequently, the heat radiation plate is operative not only to efficiently radiate the heat generated by the white LED in trade-off relation when the white LED is employed for the liquid crystal back light, but also to protect a surface light source unit even against external force applied from the outside of the liquid crystal display device housing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device that displays images, characters, and the like using a liquid crystal panel in a notebook personal computer (hereinafter referred to as a notebook personal computer), and a heat dissipation structure that emits heat from a light source constituting the liquid crystal display device.

  In recent years, an increasing number of white light emitting diodes (LEDs) are used as backlights of liquid crystal display devices using liquid crystal panels. The backlight illuminates the LCD panel from the back, and this technology is used for thin LCD panels.

  In recent years, white LEDs having a luminous efficiency exceeding 60 lm / W have appeared one after another, and the light use efficiency in practical use has reversed that of fluorescent lamps. As a result, the practical use of white LEDs instead of fluorescent lamps has rapidly increased.

Also, the backlight with white LED has the advantage that the power supply circuit is simpler than the fluorescent backlight, and the white LED is more suitable for the liquid crystal backlight where miniaturization is a proposition like a notebook computer. Yes.
JP 2006-208722 A JP 2005-121897 A

  However, the brightness of white LEDs and deterioration due to heat generation are in a trade-off relationship, and there has been a demand for measures to maintain high brightness and suppress deterioration due to heat generation.

  The present invention solves the above-mentioned conventional problems. In addition to adopting a white LED as a liquid crystal backlight to increase the brightness and simplify the configuration, heat generated from the white LED in a trade-off relationship is also provided. An object of the present invention is to provide a heat dissipation structure that emits heat.

The invention described in claim 1 of the present invention
A heat dissipating structure that constitutes a liquid crystal display device and absorbs and releases heat generated from LEDs used in a backlight of a liquid crystal panel, and the heat dissipating structure includes a base portion that supports the entire heat dissipating structure;
A heat absorbing portion in thermal contact with the LED;
A raised portion formed by raising relative to the base portion;
A support portion that is formed by further jumping up from the raised portion and is supported by the casing of the liquid crystal display device;
A heat dissipating structure characterized by being integrally formed of,
When the white LED is used for the liquid crystal backlight, the heat generated from the white LED in a trade-off relationship can be efficiently released by the heat dissipation structure of the present invention. Even with external pressure applied from outside, the heat dissipation structure of the present invention acts to protect the surface light source unit.

  As described above, the present invention not only can efficiently release the heat generated from the white LED in a trade-off relationship when the white LED is used for the liquid crystal backlight by the heat dissipation structure of the present invention. Also, an excellent effect is obtained that the heat dissipation structure of the present invention plays a role of protecting the surface light source unit against external pressure applied from the outside of the housing.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

(Embodiment 1)
FIG. 1 is a perspective view (a) of a notebook personal computer of the present invention, and (a) a cross-sectional view (b) cut along a broken line showing a display portion.

  In FIG. 1A, 10 is a notebook personal computer, 11 is a liquid crystal display device that is a display unit for displaying images, characters, and the like, and 12 is a main body unit that houses an information processing circuit such as a CPU (central processing unit). .

  In FIG. 1B, the display unit 11 generally includes a light transmission type liquid crystal panel 13 in which a liquid crystal layer is held between a pair of glass substrates, and a surface light source unit that is disposed so as to overlap the surface direction of the liquid crystal panel 13. 14 The liquid crystal panel 13 is placed on a resin frame 15 having a substantially rectangular frame shape, and the resin frame 15 is attached to and accommodated in the housing 16 so as to overlap the liquid crystal panel 13. Thereby, the liquid crystal panel 13 is held in a state of being sandwiched between the resin frame 14 and the housing 16.

  Usually, the surface light source unit 14 includes a light guide plate 141 and a white LED 142 that is a light source provided on the light guide plate 141 so as to face one side edge. Further, an optical sheet 143 composed of a plurality of sheets such as a diffusion sheet and a prism sheet is installed on the light output surface side of the light guide plate 141 for the purpose of controlling the light output characteristics, and a reflection sheet 144 is provided on the side opposite to the light output surface. It is provided and configured.

  The light guide plate 141, the optical sheet 143, the reflection sheet 144, and the white LED 142 that is a light source that constitute the surface light source unit 14 are mounted on the resin frame 15. That is, the display unit 11 is stacked in the order of the liquid crystal panel 13, the resin frame 15, the optical sheet (diffusion sheet, prism sheet, etc.) 143, the light guide plate 141, and the reflection sheet 144 in order from the light emission side. The white LED 142 is arranged, and the liquid crystal panel 13 is held between the housing 16 and the resin frame 15.

  Reference numeral 17 denotes a heat radiating plate, one end of which is thermally coupled to a white LED 142 that is a light source constituting the surface light source unit 14. The heat radiating plate 17 is preferably made of a sheet metal material that has high thermal conductivity and high strength but is easy to be rolled and rolled.

  In addition, a control circuit board including a liquid crystal panel control circuit that processes a video signal and displays an image on the liquid crystal panel 13, an LED control circuit that supplies power to the white LED 142 to control light emission, and the like is also included in the housing 16 of the display unit 11. Although it is arranged, it is omitted in the figure.

  Further, in the present embodiment, the casing 16 is molded from a light metal material such as magnesium or aluminum alloy from the viewpoint of strength and weight required for the notebook computer.

  FIG. 2 is a perspective view of a heat sink used in the liquid crystal display device of the present invention.

  In FIG. 2, the heat radiating plate is 17, A is a base portion that supports the entire heat radiating plate, B is a heat absorbing portion that is in thermal contact with the white LED, C is a raised portion that is raised from the base portion A by molding, and D is It is formed by a support part that is further substantially vertically raised from the raised part C and supported by the casing 16.

  The operation of the liquid crystal display device configured as described above will be described with reference to FIGS.

  The white LED 142, which is the light source of the surface light source unit 14 constituting the backlight, has come to be used for various light sources because the light use efficiency exceeds the fluorescent lamp, but the power supplied to the white LED element is all It is not converted into light energy, but rather the proportion of power energy converted into light energy is lower than the rate converted into heat energy. The heat energy by this has a trade-off relationship with the light emission luminance of the LED, and if the heat generated from the white LED 142 is not eliminated as much as possible by using heat radiating means, not only the light emission luminance is lowered but also the life of the white LED 142 is shortened. Also become.

  Therefore, in the liquid crystal display device of the present invention, in order to efficiently release the heat from the white LED 142, the heat radiating plate 17 (the heat radiating structure in the claims) is placed between the housing 16 and the surface light source unit 14 as shown in FIG. Is arranged. The heat radiating plate 17 is thermally coupled to the white LED 142 by the heat absorbing portion B, and is also thermally and mechanically coupled to the housing 16 molded from a lightweight metal material and also to the support portion D. .

  Further, when the heat radiating plate 17 receives external pressure from the back side of the housing 16, the heat radiating plate 17 mechanically coupled to the housing 16 further receives the external pressure, and the external pressure is transmitted through the heat radiating plate 17 to the light source unit. 14, the light guide plate 141, the optical sheet 143, and the reflection sheet 144 are deformed to cause display luminance unevenness and color unevenness of the liquid crystal panel 13.

  Further, if the heat radiating plate 17 is in contact with the surface light source unit 14, the heat generated from the white LED 142 is transmitted to the surface light source unit 14 and heats the light guide plate 141, the optical sheet 143, and the reflective sheet 144 made of a resin material. If the sheet is deformed or kept in contact for a long time, the material of each sheet material is also changed.

  Actually, in FIG. 1B, when the light guide plate 141 and the optical sheet 143 in the display area for displaying images, characters, etc. are subjected to mechanical pressure such as external pressure at one point, light is transmitted, or The material to be reflected causes white turbidity deterioration, and the display image causes white spotted pattern and wavy display unevenness.

  For this reason, the heat sink 17 of the present invention is molded as shown in FIG. 2 to form a raised portion C having no mechanical contact between the heat sink 17 and the surface light source unit 14 excluding the white LED 142. . The rising portion C ′ of the raised portion C is molded in a shape when the heat radiating plate 17 is made of metal sheet metal, and the rising portion C ′ is arranged outside the display area which is an effective display area of the image shown in FIG. It is molded into the shape that will be used.

  By doing in this way, even if external pressure is received from the back surface of the housing 16, the external pressure is transmitted in the order of the housing 16 → the support portion D → the raised portion C → the base portion A formed in the peripheral portion of the radiator plate 17, Since it is dispersed, the external pressure applied to the surface light source unit 14 can be suppressed, and the rising portion C ′ forming the raised portion C and the base portion A that finally receives the external pressure are arranged outside the display area. Therefore, image quality deterioration due to deformation of the surface light source unit 14 can be prevented.

  Further, by forming a gap between the heat radiating plate 17 and the surface light source unit 14, air convection is easily generated in this space, and the heat radiating efficiency of the heat radiating plate 17 is further increased.

  As described above, according to the present embodiment, when the white LED is used for the liquid crystal backlight, the heat generated from the white LED in a trade-off relationship is efficiently generated by the heat dissipation structure (heat dissipation plate 17) of the present invention. The heat dissipation structure of the present invention has the function of protecting the surface light source unit against external pressure applied from the outside of the housing.

  Note that a control circuit board including a liquid crystal panel control circuit that processes a video signal of a liquid crystal display device that is not shown and displays an image on the liquid crystal panel, and an LED control circuit that controls light emission by supplying power to a white LED is a surface light source. If it arrange | positions using the clearance gap between the unit 14 and the protruding part C of the heat sink 17, it can contribute also to size reduction of the display part 11 of a notebook personal computer.

  Moreover, although white LED was demonstrated to the example as a light source of a backlight, it cannot be overemphasized that the white light source by the synthetic light which consists of red, blue, and green LED may be sufficient.

  The heat dissipating structure according to the present invention not only can efficiently release the heat generated from the white LED in a trade-off relationship when the white LED is used for the liquid crystal backlight, but also the liquid crystal display device casing. The surface light source unit is protected against external pressure applied from the outside, and is useful as a liquid crystal display device in a notebook personal computer and a heat dissipation structure that emits heat from a light source that constitutes the liquid crystal display device.

(A) is a perspective view of the notebook personal computer of the present invention, (b) is a cross-sectional view taken along the broken line showing the display unit The perspective view of the heat sink used for the liquid crystal display device of this invention

Explanation of symbols

10 Notebook PC 11 Display (Liquid Crystal Display)
12 Notebook PC Main Body 13 Liquid Crystal Panel 14 Surface Light Source Unit 15 Resin Frame 16 Display Unit Housing 17 Heat Dissipation Plate (Heat Dissipation Structure)
141 Light guide plate 142 White LED
143 Optical sheet 144 Reflective sheet A Base part B Heat absorption part C Raised part D Support part

Claims (3)

A heat dissipating structure that constitutes a liquid crystal display device and absorbs and releases heat generated from an LED (Light Emitting Diode) used for a backlight of a liquid crystal panel, and the heat dissipating structure supports a whole heat dissipating structure And
A heat absorbing portion in thermal contact with the LED;
A raised portion formed by raising relative to the base portion;
A support portion that is formed by further jumping up from the raised portion and is supported by the casing of the liquid crystal display device;
A heat dissipating structure characterized by being integrally molded. The rising portion forming the raised portion is
The heat dissipation structure according to claim 1, wherein the heat dissipation structure is molded into a shape that is disposed outside a display area of the liquid crystal display device. A light transmissive liquid crystal panel for displaying images, characters, etc .;
A surface light source unit that is a backlight including white LEDs that are arranged in the surface direction of the liquid crystal panel and illuminate the liquid crystal panel;
The heat dissipation structure according to claim 1, which absorbs and releases heat generated from the white LED;
A liquid crystal display device comprising:

Images