JPH0756169A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a small-sized and thin-shaped portable device and to improve the reliability by arranging a lighting source for an illuminator under a driving IC for a liquid crystal panel. CONSTITUTION:The driving IC 72 for driving the liquid crystal is chip-on- glass(COG) mounted on the end part of the liquid crystal panel 70 which is connected with a flexible printed board 71, a fluorescent tube 50 and a reflection member 60 are arranged under the driving IC 72. Since the fluorescent tube 50 functioning as the lighting source is arranged under the COG mount part of the COG-mounted liquid crystal panel 70, the glass substrate of the COG- mounted liquid crystal panel 70 functions as the supporting table for the driving IC 72. And also, since the fluorescent tube 50 is arranged under the COG mount of the COG-mounted liquid crystal panel 70, a space used only for the fluorescent tube 50 in the liquid crystal display device is unnecessitated, and also, the loss of a display signal due to connection wiring is reduced since the driving IC 72 comes close to the liquid crystal panel 70, and the portable device is formed since the pattern of wiring arranged from the circuit substrate to the driving IC 72 can be cut down.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device using a liquid crystal panel as an image display means.

[0002]

2. Description of the Related Art In recent years, a liquid crystal display device, which is small and suitable for portability, has been used in various fields as seen in a small portable television or the like. Under such circumstances, various liquid crystal display devices have been proposed.

Examples of conventionally proposed liquid crystal display devices include Japanese Patent Laid-Open Nos. 60-214684 and 63-63.
As disclosed in Japanese Patent No. 282778 and Japanese Utility Model Laid-Open No. 2-78926, a liquid crystal panel having a function as a passive element, and an illumination device or a liquid crystal display device for clearly displaying at least an image displayed on the liquid crystal panel to the liquid crystal panel. Further, it is composed of a circuit board having a signal processing circuit for converting an electric signal input or received from an external signal source into a liquid crystal panel drive signal, or a frame body for housing the member.

FIG. 4 shows an example of a conventional liquid crystal display device.
And Figure 5 is given. A cross section taken along the line AA centering on the liquid crystal panel portion of the liquid crystal display device shown in FIG. 4 is shown as shown in FIG. In FIG. 5, a windshield 96 for protecting the liquid crystal panel 70 is provided on an upper frame 95 of a frame body composed of a lower frame 90 and an upper frame 95, and the windshield 96 is adhesively fixed to the upper frame 95. Windshield 96
A liquid crystal panel 70 is disposed below the liquid crystal panel 70, and a lighting device 55 is disposed below the liquid crystal panel 70.

In the illuminating device 55 shown in FIG. 5, the viewing angle correcting member 41 is arranged in a portion close to the liquid crystal panel 70. The viewing angle correction member 41 has a function of viewing an image on the liquid crystal panel 70 obliquely with respect to the front surface of the liquid crystal panel 70 so that the image can be viewed in a state where the image is viewed from the front and there is no discoloration. A diffusing member 40 having a function of uniformly distributing light from a fluorescent tube, which is a light source, to the liquid crystal panel 70 is disposed below the viewing angle correcting member 41.
A light guide member 30 is disposed below the light guide member 30, and a fluorescent tube 50, which is a light source, is disposed on a side surface of the light guide member 30 to avoid an end portion of the light guide member 30 and a facing portion of the fluorescent tube 50. Reflective member 60
Are arranged so as to wind the fluorescent tube 50, and the reflecting member 6 is mounted on the base 10.
0, the fluorescent tube 50, the light guide member 30, the diffusion member 40, and the viewing angle correction member 41 are sequentially assembled to complete the illumination device 55.

The illumination device 55 is supported by a lower frame 90 and an upper frame 95 via a circuit board 80. A flexible printed circuit board (hereinafter referred to as FPC) 71, which is a wiring member on which a drive IC 72 for driving liquid crystal is mounted, is connected to an end portion of the liquid crystal panel 70.
The end of the FPC on the opposite side is connected to the circuit board 80 by line soldering, conductive bonding, or a connector.

As shown in FIG. 5, the driving IC 72 mounted on the FPC 71 is curved as the liquid crystal display device is made smaller, and therefore the driving IC 72 is F-shaped.
There is a problem that it becomes easy to peel off from the PC 71 and the reliability deteriorates. In order to prevent the drive IC 72 from coming off, FIG.
The structure of is disclosed. In the structure of FIG. 6, a support portion that supports the drive IC 72 is formed on the lower frame 90, and the support portion 91 supports the drive IC 72 and the FPC 71 to prevent the drawback of FIG.

[0008]

In FIG. 6 which is the prior art, since the supporting portion 91 for supporting the drive IC 72 is required, the thickness dimension of the liquid crystal display device is increased by the thickness amount of the supporting portion 91, so that it is portable. In addition to being unsuitable for sex, the lower frame 90
When it is produced by injection molding, a U-shaped mold surrounding the fluorescent tube 50 is formed, which causes a problem such as an increase in mold cost. Further, even if the downward movement of the drive IC 72 is suppressed by the support base of 91, the upward movement cannot be suppressed, which is not a complete countermeasure against the peeling of the drive IC. Even drive IC7
Even if it is fixed by a double-sided adhesive member between 2 and the support portion 91, there arises a new problem that the material cost of the double-sided contact material, the assembly processing cost, and the workability in repairing are poor.

Further, in the conventional liquid crystal display device of a portable computer, a method of mounting a drive IC for driving liquid crystal on a circuit board and connecting an end portion of the liquid crystal panel and the circuit board with an FPC is often used. However, because the drive IC is mounted on the FPC, the wiring resistance to the liquid crystal panel becomes high,
There are problems that the stray capacitance increases and the wiring pattern of the FPC increases, making it difficult to connect the FPC to the liquid crystal panel or the FPC to the circuit board.

An object of the present invention is to solve the above problems and to provide a small-sized, thin, highly reliable liquid crystal display device particularly suitable for carrying.

[0011]

In order to solve the above problems, a first invention of the present invention relates to a COG mounting in which a driving IC having a circuit for driving a liquid crystal is mounted on a transparent substrate forming a liquid crystal panel. A liquid crystal display device comprising a liquid crystal panel and an illuminating device for illuminating the liquid crystal panel, wherein the illumination source of the illuminating device is arranged below the drive IC of the liquid crystal panel. It is what A second invention of the present invention is a liquid crystal display device characterized in that a heat insulating member is provided between the drive IC and the illumination source provided below the drive IC. A third invention of the present invention is a liquid crystal display device characterized in that a wiring member for connecting the liquid crystal panel and the circuit board is arranged substantially concentrically with the illumination source.

[0012]

By the means for solving the above-mentioned problems, since the fluorescent tube as the illumination source is arranged below the COG mounting portion of the liquid crystal panel on which the chip-on-glass (COG) is mounted, C
Since the glass substrate of the OG-mounted liquid crystal panel has a function of a support base for the driving IC and the fluorescent tube is arranged below the COG-mounted COG-mounted liquid crystal panel, it is only for the fluorescent tube. The space inside the liquid crystal display device becomes unnecessary, and since the drive IC and the liquid crystal panel are close to each other, display signal loss due to connection wiring can be reduced, and the wiring pattern from the circuit board to the drive IC can be reduced. A liquid crystal display device suitable for carrying can be obtained.

By disposing a heat insulating member between the COG mounting portion of the liquid crystal panel and the fluorescent tube which is the illumination source, it is possible to obtain an action of preventing malfunction and deterioration of the COG mounting drive IC due to heat generation of the fluorescent tube. .

Further, the wiring member for connecting the liquid crystal panel and the circuit board is arranged substantially concentrically with the illumination source, so that the wiring space of the wiring member can be minimized.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below with reference to the drawings. 1 is a partially exploded view of a liquid crystal display device showing an embodiment of the present invention. In FIG. 1, the upper frame 95 is omitted. Figure 2
FIG. 2 is a sectional view taken along line BB in FIG. 1, which is an embodiment of the present invention. FIG. 2 shows a state in which the upper frame 95 is arranged.

In FIG. 1 and FIG. 2, the liquid crystal display device 2 has a circuit board 80 and a base 10 arranged on a lower frame 90, and the base 10 has a light guide member base 12 and a fluorescent tube base. A base 11 is provided. In the fluorescent tube base portion 11 of the base 10, a reflecting member 60, which is a part of the configuration of the lighting device and reflects the light of the light source toward the light guide member 30, and a fluorescent tube 50 which is a light source are housed. The light guide member 30 is housed in the light guide member base portion 12. A diffusion member 40 is arranged above the light guide member 30. As described above, in FIG. 3 of the embodiment,
The lighting device includes a reflection member 60, a fluorescent tube 50, a light guide member 30, and a diffusion member 40.

Although not shown, a visual angle correction member may be provided above the diffusing member 40 to reduce a change in image quality depending on the viewing angle of the observer, and the light guiding member 30 outputs the light to the diffusing plate 40. In some cases, a light amount adjusting member for uniformizing the light may be provided, and the order of superimposing the diffusing member 40, the viewing angle correction plate, and the light amount adjusting member and the combination of the various members described above may be changed to obtain the optimum image quality for the viewer. A certain level of light is obtained, a good-looking brightness and a visual state with little viewing angle dependence are obtained, and the specific combination of members is determined by the product design specifications of the liquid crystal display device. .

A liquid crystal panel 70 is disposed above a reflecting member 60 which partially covers the diffusing member 40 and the fluorescent tube 50. An FPC 71 is connected to the end of the liquid crystal panel 70 by a conductive adhesive, and the liquid crystal panel 70 of the FPC 71 is connected.
The end portion on the opposite side to the circuit board 80, which passes through the cutout portion 14 of the base 10 and is disposed below the light guide member base portion 12 of the base 10, has line solder connection or conductive adhesive connection or Connected by a connector.

As shown in FIG. 2, a driving IC 7 for driving the liquid crystal is provided at the end of the liquid crystal panel 70 connected to the FPC 71.
2 is mounted by COG, and the fluorescent tube 72 and the reflection member 60 are arranged below the drive IC 72.

The reflecting member 60 disposed below the driving IC 72 is generally made of white polyester, polycarbonate, or aluminum vapor-deposited film, but in the embodiment, polyester is used. FIG. 3 shows a view in which the heat insulating member 61 is arranged.
By inserting a heat insulating member between the reflection member 60 and the drive IC 72, the effect of protecting the drive IC against heat generation of the fluorescent tube is improved. As the heat insulating material, a rubber or plastic heat insulating member is effective.

As shown in FIG. 1, a supporting member 20 is provided above the liquid crystal panel, and the cut groove 21 provided in the supporting member 20 and the hook portion 13 of the base 10 are joined to each other to form the base 1.
0 is a unit of the above-mentioned members such as the light guide member 30, the fluorescent tube 50, and the reflection member 60. The liquid crystal display unit 1 in which the support member 20 is unitized by the base 10 and the circuit board 80 are housed in the lower frame 90, and the upper frame 95 is disposed above the liquid crystal display unit 1 to obtain a liquid crystal display device. .

The lead terminal of the fluorescent tube 50 is connected to the circuit board 80.
As a method of connecting to the fluorescent tube driving circuit mounted in the above, the lead terminal of the fluorescent tube 50 may be directly soldered to the circuit board 80 or connected by a connector. Although not shown, in the embodiment, an auxiliary substrate is provided below the fluorescent tube base 11, and the lead terminal of the fluorescent tube 50 and the circuit board 80 are connected via the auxiliary substrate.

As shown in FIG. 2, an FPC 71, which is an example of a wiring member, is connected to the end of the liquid crystal panel 70, and a circuit board 80 is connected to the other end of the FPC 71. The connection between the circuit board 80 and the end of the FPC 71 is
Any means such as connector connection, line solder connection, or conductive adhesive may be used. The FPC 71 connected to the liquid crystal panel 70 passes through the cutout portion 14 of the base 10 and the fluorescent tube 5
0, the reflecting member 60, and the fluorescent tube base 11 are arranged so as to cover the fluorescent board 50, and then connected to the circuit board 80 below the base 10 and have the shortest wiring configuration substantially concentric with the fluorescent tube 50.

[0024]

As described above, the present invention does not require a member for supporting a driving IC, and therefore a liquid crystal display device smaller in size and a liquid crystal display device lower in price than the conventional one can be obtained.

Further, the lower portion of the COG mounting portion of the liquid crystal panel has conventionally been used as a housing portion for the connection wiring FPC for connecting the COG and the circuit board. A liquid crystal display device which is convenient for carrying can be obtained.

By disposing a heat insulating member between the COG mounting portion of the liquid crystal panel and the fluorescent tube which is the illumination source, malfunction and deterioration due to heat generation of the fluorescent tube can be prevented, and the reliability of the small liquid crystal display device is improved. The effect of improving the property is obtained.

Further, the wiring member for connecting the liquid crystal panel and the circuit board is arranged substantially concentrically with the illumination source, so that the wiring space of the wiring member can be minimized. Further, the liquid crystal panel and the circuit board are connected to each other, and the base and the circuit board having the liquid crystal panel built therein are integrated, and then the lower frame or the upper frame is assembled, thereby improving the efficiency of the assembling work.

[Brief description of drawings]

FIG. 1 is a partially exploded view of a liquid crystal display device showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the liquid crystal display device showing the first embodiment of the present invention.

FIG. 3 is a sectional view of a liquid crystal display device showing a second embodiment of the present invention.

FIG. 4 is an external view showing an example of a liquid crystal display device.

FIG. 5 is a liquid crystal display device for showing a first conventional technique.
FIG.

FIG. 6 is a liquid crystal display device showing a second conventional technique.
FIG.

[Explanation of symbols]

 10 Base 11 Fluorescent Tube Base 12 Light Guide Member Base 13 Hook 14 Notch 20 Supporting Member 21 Notch 50 Fluorescent Tube 60 Reflecting Member 61 Thermal Insulation 70 Liquid Crystal Panel 71 FPC

Claims (3)

[Claims] 1. A COG in which a driving IC having a circuit for driving a liquid crystal is mounted on a transparent substrate forming a liquid crystal panel.
A liquid crystal display device comprising a mounted liquid crystal panel and an illuminating device for illuminating the liquid crystal panel, wherein the illumination source of the illuminating device is arranged below the drive IC of the liquid crystal panel. Display device. 2. The liquid crystal display device according to claim 1, wherein a heat insulating member is provided between the drive IC and the illumination source provided below the drive IC. 3. The liquid crystal display device according to claim 1, wherein a wiring member that connects the liquid crystal panel and the circuit board is arranged substantially concentrically with the illumination source.