JP4702762B2 - Liquid crystal display - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device in which a backlight housing case as a casing constituting the liquid crystal display device is integrally provided with a heat dissipation structure.
[0002]
[Prior art]
In recent years, liquid crystal display devices have been widely used as display devices for notebook computers (notebook personal computers), display monitors, or television receivers that can display high-definition, thin, light weight and color display. A liquid crystal display panel constituting this type of liquid crystal display device needs to apply illumination light from the outside in order to visualize an electronic latent image formed on the liquid crystal display panel.
[0003]
Illumination light sources include those using external light and structures in which an illumination device is disposed on the back or front of a liquid crystal display panel. The lighting device installed on the back is called a backlight, and the lighting device installed on the front is called a front light. In a liquid crystal display device used for a notebook personal computer, a display monitor, or a television receiver, a structure having a backlight of a direct system that uniformly illuminates a liquid crystal display panel from the back is generally used in order to display a clear image.
[0004]
FIG. 5 is a diagram showing an example of a liquid crystal display device having a backlight of this type, where FIG. 5 (a) is a side sectional view and FIG. 5 (b) is a schematic plan view. In FIG. 5, a liquid crystal panel 3 is fixedly disposed via a mounting frame 2 on the front side of a case 1 made of wood or a resin material. In addition, a backlight device 4 for irradiating irradiation light from behind is disposed in the case 1 to make the image display of the liquid crystal panel 3 clear.
[0005]
In the light source of the backlight device 4, for example, a tubular cathode fluorescent tube 5 is arranged extending in the left-right direction toward the front of the device. Behind this cathode fluorescent tube 5 is provided a pyramid-shaped reflector 6 that prevents light from being scattered back and not being used effectively. Further, a diffusion plate 7 is attached between the front enlarged portion of the reflector 6 and the liquid crystal panel 3 using the attachment frame 2. The diffusion plate 7 diffuses and equalizes direct light radiated from the cathode fluorescent tube 5 and reflected light from the reflector 6 and irradiates the liquid crystal panel 3 with light emitted therefrom from behind.
[0006]
A circuit board 11 on which a plurality of types of drive circuits 8 for driving the liquid crystal panel 3, a control circuit 9, a drive power supply circuit 10 for the cathode fluorescent tube 5 and the like are mounted is mounted on the bottom side of the case 1. Although not shown, the circuit board 11, the liquid crystal panel 3, and the cathode fluorescent tube 5 are electrically connected to each other through an FPC or the like.
[0007]
Further, in order to suppress an increase in the internal temperature due to heat generation of the cathode fluorescent tube 5 inside the case 1, a heat radiating member is integrally provided in the case 1, and the heat generated in the cathode fluorescent tube 5 is transmitted to the case 1 through the heat medium member. There is also a structure that heats and releases heat to the outside. Further, in order to prevent overheating of the liquid crystal panel 3 and its polarizing plate, there is a structure in which a heat radiating member is integrally provided on the mounting frame 2 of the liquid crystal panel 3 to prevent thermal damage due to an air cooling effect. In addition, regarding this type of prior art, for example, the following Patent Document 1 and Patent Document 2 can be cited.
[0008]
[Patent Document 1]
JP-A-8-262440 [Patent Document 2]
JP 2000-147472 A [0009]
[Problems to be solved by the invention]
However, the liquid crystal display device configured in this way has a decrease in the luminous efficiency of the cathode fluorescent tube 5 due to a temperature increase inside the case 1 accompanying the heat generation of the cathode fluorescent tube 5, and the polarization of the liquid crystal panel 3 and the like. There has been a problem that the light emission luminance of the liquid crystal panel 3 due to the temperature rise due to light irradiation on the plate is lowered, and the quality and reliability are impaired.
[0010]
Further, the liquid crystal display device configured as described above includes a case 1 that surrounds the entire configuration of the liquid crystal display device, a mounting frame 2 that supports and fixes the liquid crystal panel 3, and a heat radiating member that radiates heat from various drive circuits. The component parts are individually manufactured by die casting (casting) method using, for example, an aluminum alloy as the main material. Therefore, the number of parts such as heat radiation members is increased, the manufacturing cost is increased by increasing the number of assembly steps, and the cost is reduced. It was impossible to realize.
[0011]
Accordingly, the present invention has been made to solve the above-described conventional problems, and the object thereof is to reduce the number of parts and the manufacturing cost by forming the casing and the heat radiating member by integral molding. In addition, an object of the present invention is to provide a liquid crystal display device capable of ensuring mechanical strength.
[0012]
[Means for Solving the Problems]
In order to achieve such an object, a liquid crystal display device according to the present invention includes a liquid crystal display panel, a panel frame for supporting and fixing the liquid crystal display panel, and a plurality of cold cathode fluorescent lamps inside the liquid crystal display panel facing the back surface. And a liquid crystal display panel drive circuit board installed on the outer surface of the backlight storage case. And an inverter circuit board of a cold cathode fluorescent lamp installed on the outer surface of the backlight storage case, and a power circuit board installed on the outer surface of the backlight storage case, and the heat dissipating member includes a drive circuit board and an inverter circuit board In addition, by installing it in an empty space on the outer surface of the backlight storage case where no power circuit board is installed, Reducing the internal temperature of a scaling storage case.
[0013]
According to the above-described configuration of the present invention, preferably, the backlight storage case is formed by integrally molding the alloy material by the die casting method, thereby reducing the number of components and reducing the manufacturing cost, and storing the backlight. Case rigidity is secured.
[0014]
It should be noted that the present invention is not limited to the above-described configuration and the configuration of each embodiment described later, and it goes without saying that various modifications can be made without departing from the technical idea of the present invention.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings of the embodiments.
FIG. 1 is a plan view of an essential part for explaining the external appearance of a liquid crystal television receiver according to an embodiment of the liquid crystal display device of the present invention. In FIG. 1, the liquid crystal television receiver is composed of a backlight storage case BLC corresponding to a housing or cabinet and a stand STD that supports the backlight storage case BLC. Is provided with a display DSP. In this display portion DSP, as shown in the developed perspective view of FIG. 2, a liquid crystal display panel PNL having a relatively large diagonal dimension screen is supported and fixed to a frame-like panel frame PNF having an L-shaped cross section. A display device is mounted, and the effective display area of the liquid crystal display panel PNL serving as the screen of the liquid crystal display device has a structure exposed to the display unit DSP.
[0016]
Further, as shown in FIG. 2, on the back side of the liquid crystal display panel PNL mounted and supported by the panel frame PNF, a plurality of cold cathode fluorescent light sources as light sources are provided so as to face the main surface of the liquid crystal display panel PNL. There is installed a backlight storage case BLC in which lamps CFL are arranged in parallel and a backlight storage portion BL having a light reflecting surface (not shown) is formed on the inner surface side. This backlight storage case BLC reflects the illumination light of the cold cathode fluorescent lamp CFL from the back surface of the liquid crystal display panel PNL on the light reflecting surface constituting a part of the backlight storage portion BL, and projects it onto the back surface of the liquid crystal display panel PNL. It has a direct type (backlight) structure.
[0017]
Further, on the back surface (back surface) side of the backlight storage case BLC, as shown in a perspective view in FIG. 3, a drive circuit board DRB on which an electronic circuit component IC for driving various operations of the liquid crystal display panel PNL is mounted and a cold cathode Inverter circuit boards INB1 and INB2 for driving the fluorescent lamp CFL to light, and the drive circuit board DRB and the power supply circuit board PSB for supplying the required high voltage to the inverter circuit boards INB1 and INB2, respectively, have the drive component mounting surface side as the outer surface. Although not shown, it is mounted and fixed via an insulator. These drive circuit board DRB and inverter circuit boards INB1 and INB2 are electrically connected to the corresponding liquid crystal display panel PNL and cold cathode fluorescent lamp CFL by a flexible printed board or wiring (not shown) inside the backlight storage case BLC, respectively. It is structured to be connected to.
[0018]
Further, on the back surface of the backlight storage case BLC, the drive circuit board DRB, the inverter circuit board INB1, the inverter circuit board INB2, the power supply circuit board PSB and the like are not installed on the back side of the space. Radiation fins RAD1, RAD2, RAD3, and RAD4 made up of a plurality of groups of radiation fins RAD having plate-like protrusions are integrally provided. The backlight storage case BLC, the backlight storage portion BL and the radiation fins RAD1, RAD2, RAD3, RAD4 are integrally formed by die casting (casting) method using iron alloy, aluminum alloy, magnesium alloy or zinc alloy as a main raw material. Has been made. In addition, these radiation fins RAD1, RAD2, RAD3, and RAD4 are specifically configured to be inconspicuous from the front side of the cabinet part CAB in terms of appearance.
[0019]
In such a configuration, the heat radiation fins RAD1, RAD2, RAD3, RAD4 can be protruded from the back surface of the backlight storage case BLC and integrally formed, thereby increasing the heat radiation area by the heat radiation fins RAD1, RAD2, RAD3, RAD4. Therefore, it is possible to suppress the temperature rise caused by the heat generation of the cold cathode fluorescent lamp CFL installed in the backlight storage case BLC, and thereby the luminance and luminous efficiency due to insufficient cooling of the cold cathode fluorescent lamp CFL. Can be reliably prevented. Further, since retrofitting of air cooling parts such as heat radiating fins conventionally performed is not necessary, the number of parts can be reduced, and the manufacturing cost can be greatly reduced.
[0020]
Further, in such a configuration, the heat radiation effect can be increased by integrally forming the heat radiation fins RAD1 to RAD4 on the back surface of the backlight storage case BLC. Since the cold cathode fluorescent lamp CFL can be installed and the light emission luminance and light emission efficiency can be improved, a display screen with high luminance can be obtained.
[0021]
Further, in such a configuration, the backlight storage case BLC and the heat radiation fins RAD1 to RAD4 can be integrally formed by a die casting method, so that the main skeleton machine constituting the backlight storage case BLC as a casing is formed. Since the mechanical strength increases, it is possible to ensure the rigidity associated with the increase in weight due to the increase in size.
[0022]
Further, in such a configuration, the heat radiation fins RAD1 to RAD4 are integrally formed on the back surface of the backlight storage case BLC, so that the heat radiation fins RAD1 to RAD4 protrude from the back surface of the backlight storage case BLC. Since the depth dimension of the module itself excluding the protruding portions of RAD1 to RAD4 can be configured to be short (thin), the apparatus can be easily reduced in thickness.
[0023]
Further, in such a configuration, the drive circuit board DRB, the inverter circuit board INB1, the inverter circuit board INB2, and the power supply circuit board PSB are installed on the back surface of the backlight storage case BLC, so that the electronic components mounted on each circuit board Therefore, the temperature characteristics of the electronic circuit components on the various circuit boards can be maintained in the best environment, and a stable driving operation that is not affected by the temperature rise can be obtained.
[0024]
FIG. 4 is a perspective view seen from the back side of the liquid crystal television receiver for explaining the configuration of the liquid crystal display device according to another embodiment of the present invention. The same parts as those in FIG. The description is omitted. 4 differs from FIG. 3 in that the heat radiation fins RAD5 and RAD6, which are a plurality of heat radiation fins RAD having needle-like protrusions with a small cross-sectional area, are integrally formed symmetrically on the upper surface of the backlight storage case BLC. On the back surface of the backlight storage case BLC, heat radiation fins RAD7 and RAD8 made up of a plurality of plate-shaped heat radiation fins RAD are integrally formed symmetrically along the height direction.
[0025]
In the liquid crystal display device configured in this way, the heat radiation fins RAD5 and RAD6 having needle-shaped protrusions having a small cross-sectional area are disposed symmetrically on the upper surface of the backlight storage case BLC, thereby transmitting the heat radiation fins RAD5 and RAD6. Since the heat area is increased and the heat dissipation area is expanded, in addition to the heat dissipation effect described above, the heat staying in the upper part of the backlight storage case BLC can be efficiently dissipated. In addition to the heat dissipation effect described above, the backlight storage case BLC is configured by arranging plate-like heat radiation fins RAD7 and RAD8 symmetrically along the height direction on the back surface of the backlight storage case BLC. Since the mechanical strength of the skeleton is further improved and the rigidity is sufficiently ensured, the backlight storage case BLC can be stacked and transported in a plurality of stages as a single unit.
[0026]
In each of the above-described embodiments, the case where the backlight storage case and the heat radiation fin are integrally formed by die casting (casting) using various alloy materials as raw materials has been described. However, the present invention is not limited thereto. However, the same effects as described above can be obtained even if the molding is performed by a high pressure press molding method that mechanically applies a high pressure to the metal material as a molding method other than the die casting method.
[0027]
Further, in each of the above-described embodiments, the case where a plate-like heat radiation fin or a heat radiation fin having a needle-like protrusion with a small cross-sectional area is used as the heat radiation member has been described, but the present invention is not limited to this. However, the same effect as described above can be obtained even if a thin blade-like radiating fin is used. Also in this case, the heat transfer area of the radiating fin is increased and the heat radiating area is expanded, so that the air cooling effect can be further improved.
[0028]
Further, in each of the embodiments described above, the case where a plurality of heat radiation fins as heat radiation members installed on the back surface of the backlight storage case are integrally installed symmetrically is described, but the present invention is limited to this. It may be installed in an empty area or a side surface where no drive circuit board, inverter circuit board, power supply circuit board, etc. are arranged, and the installation location and the shape of the heat radiation fins are particularly limited. It is not something.
[0029]
In the above-described embodiments, the case where the present invention is applied to a liquid crystal television receiver using a liquid crystal display panel has been described. However, the present invention is not limited to this, and a PDP (plasma display panel) or FPD (flat) is used. Of course, the same effect as described above can be obtained even when applied to a backlight storage case such as a panel display.
[0030]
【The invention's effect】
As described above, according to the liquid crystal display device according to the present invention, the heat radiation member is integrally formed on the outer surface of the backlight storage case, thereby improving the cooling function of the cold cathode fluorescent lamp by high luminance light emission and the heat radiation member. As a result, the production cost can be reduced by reducing the number of parts that are not required for mounting, and the rigidity can be secured as the weight increases due to the increase in size.
[0031]
In addition, according to the liquid crystal display device of the present invention, the drive circuit board, the inverter circuit board, and the power circuit board are installed on the back surface of the backlight storage case, thereby reducing the thickness of the module itself excluding the protrusion of the heat dissipation member. Therefore, it is possible to obtain extremely excellent effects such as a reduction in the depth dimension of the liquid crystal display device and a reduction in thickness.
[Brief description of the drawings]
FIG. 1 is a plan view of an essential part showing the appearance of a liquid crystal television receiver according to an embodiment of a liquid crystal display device according to the present invention;
FIG. 2 is a development of a main part showing the internal structure of the backlight storage case shown in FIG. 1;
3 is a perspective view showing a back structure of the backlight storage case shown in FIG. 1. FIG.
FIG. 4 is a perspective view showing a back structure of a backlight storage case according to another embodiment of the liquid crystal display device according to the present invention.
FIG. 5 is a diagram showing a configuration of a conventional liquid crystal display device.
[Explanation of symbols]
PNL LCD panel PNF Panel frame BLC Backlight storage case DSP Display section STD Stand section BL Backlight storage section CFL Cold cathode fluorescent lamp IC Electronic circuit component DRB Drive circuit board INB1 Inverter circuit board INB2 Inverter circuit board PSB Power supply circuit board RAD Heat dissipation Fin RAD1 Radiation fin RAD2 Radiation fin RAD3 Radiation fin RAD4 Radiation fin RAD5 Radiation fin RAD6 Radiation fin RAD7 Radiation fin RAD8 Radiation fin

Claims (4)

A liquid crystal display panel;
A panel frame for supporting and fixing the liquid crystal display panel;
A backlight storage case made of a metal member installed on the panel frame and integrally formed with a heat dissipation member on the outside;
The heat dissipating member is arranged so that a first heat dissipating fin having a large number of fins and a second heat dissipating fin having a smaller number of fins than the first heat dissipating fin are in a vertical relationship with the first heat dissipating fin. A liquid crystal display device.   The first heat dissipating fin having a large number of fins, the third heat dissipating fin having a large number of fins spaced apart in the left-right direction, and the fourth heat dissipating fin when the number of fins is smaller than the third heat dissipating fin. 2. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is arranged so as to be in a vertical relationship.   The liquid crystal display device according to claim 2, wherein an inverter substrate is disposed outside the second heat radiation fin or the fourth heat radiation fin. The liquid crystal display device according to claim 2, wherein a power supply circuit board is disposed between said second heat radiating fins fourth radiating fin.

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