JPH0534713A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display device which is small in size and low cost, lightweight, and thin in thickness and can excellently be assembled and disassembled. CONSTITUTION:A setting parts 29 for printed wiring boards 5a and 5b is recessed in the reverse surface side of the fitting part of a mold case 8 for a liquid crystal display panel and a fixed hook 27 and an elastic arm 28 for holding the printed wiring boards detachably are arranged on both sides of the setting part opposite each other. An easy-to-deform part 13 is provided at part of a flexible substrate 2 where a driver IC 4 is mounted to make the flexible substrate bendable. The flexible substrate is bent along an end side of the mold case and the printed wiring boards are arranged on the reverse surface side of the mold case. The printed wiring boards 5a and 5b are fitted in the setting part and mounted by snapping between the fixed hook and elastic arm.

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 integrally including a mold case, a liquid crystal display panel, a printed wiring board and a flexible substrate, and more particularly to a mounting structure of the printed wiring board to the mold case. .

[0002]

2. Description of the Related Art Conventionally, a liquid crystal display panel and a printed wiring board on which a necessary circuit pattern is formed are mounted on a mold case made of a plastic material, and a signal electrode group formed on these liquid crystal display panels is used. A liquid crystal display device is known in which a circuit pattern formed on the printed wiring board is electrically connected via a flexible substrate on which a necessary lead pattern is formed.

As a mounting structure for the mold case and the printed wiring board in this type of liquid crystal display device, a structure in which both members are bonded together via a double-sided adhesive tape,
A structure in which a screw insertion hole is opened in the printed wiring board and a female screw is formed in the molded case, and the both ends of the screw inserted in the screw insertion hole are screwed into the female screw to fix both members, the printed wiring board and the molded case. In addition to opening the screw insertion hole, separately prepare a metal plate on which a female screw is formed, and fix both members by screwing the tip end of the screw that is continuously penetrated into the screw insertion hole of both members into the female screw of the metal plate. There are structures, etc.

The arrangement structure of the printed wiring board in the liquid crystal display device is, for example, Japanese Patent Laid-Open No. 2-1378.
As described in Japanese Patent Laid-Open No. 22-22, a signal electrode group formed on a liquid crystal display panel and a circuit pattern formed on a printed wiring board are electrically connected via a film connector on which a necessary lead pattern is formed. Then, the structure in which the printed wiring board is arranged on the back side of the liquid crystal display panel by bending the film connector, and the necessary lead pattern for the signal electrode group formed on the liquid crystal display panel and the circuit pattern formed on the printed wiring board There is a structure in which the printed wiring board is formed and electrically connected via a flexible substrate on which a driver IC is mounted on the lead pattern, and the printed wiring board is arranged in the same plane direction as the liquid crystal display panel.

[0005]

By the way, in a liquid crystal display device used as a display device of a portable personal computer or a word processor, downsizing, thinning, weight reduction, and cost reduction are the most important technical factors. It is one of the challenges.

The above-mentioned conventional printed wiring board mounting structure is effective for making the device thinner and lighter, but since the mold case and the printed wiring board are firmly adhered by the double-sided adhesive tape, It is difficult to remove the printed wiring board from the mold case without damaging it.
Even if the printed wiring board can be peeled off from the mold case without damaging the printed wiring board, a great amount of labor is required to remove the double-sided adhesive tapes attached to these members and make them re-adhesive. Therefore, there is an inconvenience that it is difficult to disassemble and repair. On the other hand, the above methods and are not inconvenient as mentioned above, but the number of parts is large, so that the liquid crystal display device is high in cost and weight, and the structure of the mold case and the printed wiring board is structurally high. Since the screw head and the tip of the screw protrude from the surface,
There is a disadvantage that the total thickness of the liquid crystal display device becomes large.
Particularly, in the above method, such inconvenience becomes remarkable.

Further, as described above, in the liquid crystal display device in which the liquid crystal display panel and the printed wiring board are electrically connected via the film connector, the printed wiring board is attached to the back surface of the liquid crystal display panel by bending the film connector. Although the one arranged on the side is conventionally known (of the arrangement structure of the printed wiring board), the driver IC
For a liquid crystal display device in which a liquid crystal display panel and a printed wiring board are electrically connected via a flexible board on which is mounted, the printed wiring board is displayed on the liquid crystal display because the flexible board cannot be bent at a sharp angle. There is nothing placed on the back side of the panel, and we cannot meet the demand for miniaturization.

The present invention solves the above-mentioned drawbacks of the prior art, is excellent in assembling / disassembling property, and is attached to a printed wiring board which is effective for downsizing, thinning, weight reduction and cost reduction of a liquid crystal display device. It is intended to provide a structure.

[0009]

In order to achieve the above object, the present invention provides a mold case formed of a hard plastic material, a liquid crystal display panel mounted on one side of the mold case, and a necessary circuit. A printed wiring board on which a pattern is formed and the necessary lead pattern are formed,
Moreover, the driver IC is mounted on the lead pattern,
A liquid crystal display device including a flexible substrate electrically connecting a signal electrode group formed on the liquid crystal display panel and a circuit pattern formed on the printed wiring board via the lead pattern, wherein the mold case is provided. The setting portion of the printed wiring board is recessed on the back side of the liquid crystal display panel mounting surface, and a fixing hook and an elastic arm for detachably holding the printed wiring board are provided on both sides of the setting portion through the setting portion. The flexible printed circuit board was arranged so as to face each other, and an easily deformable portion was provided on a part of the flexible printed circuit board so that the flexible printed circuit board could be bent, and the printed wiring board was snap-fitted between the fixed hook and the elastic arm.

[0010]

In order to prevent the printed wiring board from falling off by the fixed hook and the elastic arm, the fixed hook and the elastic arm must be projected in the thickness direction beyond the surface of the printed wiring board. However, when the setting portion of the printed wiring board is recessed in the mold case as shown in the above means, it is possible to absorb the protrusion amount of the fixing hook and the elastic arm in the thickness direction due to the depth of the setting portion. There is no need to increase the total thickness of the display device. Also, if a fixed hook and elastic arm are provided on the molded case itself,
Since the number of parts is not increased, the cost and weight of the device are not increased. Further, when the printed wiring board is snap-fitted with the fixed hook and the elastic arm, the printed wiring board can be attached and removed any number of times, so that the assembling / disassembling property is remarkably improved. In addition, when the easily deformable portion is provided in a part of the flexible board, the flexible board can be bent, and the flexible board can be bent from the liquid crystal display panel mounting surface side of the mold case to the back surface side. Therefore, the printed wiring board can be disposed on the back surface side of the liquid crystal display panel, and the liquid crystal display device can be downsized.

[0011]

EXAMPLES An example of a liquid crystal display device according to the present invention will be described below.
Description will be made with reference to FIGS. 1 is a cross-sectional view of a main part of a liquid crystal display device, FIG. 2 is a development explanatory view of a liquid crystal display device on which a printed wiring board and a flexible substrate are mounted, FIG. 3 is an enlarged plan view of a flexible substrate, and FIG. 4 is a plan view of a mold case. FIG. 5 is a back view of the molded case. In these figures, 1 is a liquid crystal display panel, 2 is a flexible substrate, 3 is a segment driver IC, 4 is a common driver IC, 5a, 5b and 5c are printed wiring boards, 7 is a connection cable, and 8 is a molded case. There is.

As shown in FIG. 2, the liquid crystal display panel 1 of this example is connected with four flexible boards 2 along the upper edge, the lower edge and the left edge, and the other ends of the flexible boards 2 at the respective portions are connected. They are connected to the upper printed wiring board 5a, the lower printed wiring board 5b, and the left printed wiring board 5c, respectively. The upper printed wiring board 5a and the left printed wiring board 5c, and the lower printed wiring board 5b and the left printed wiring board 5c are connected via a connection cable 7. Two segment driver ICs 3 are mounted on each of the flexible substrates 2 connected along the upper edge and the lower edge of the liquid crystal display panel 1, and are connected along the left edge of the liquid crystal display panel 1. One common driver IC 4 is mounted on each flexible substrate 2.

The liquid crystal display panel 1 includes an upper glass substrate 1a.
And the lower glass substrate 1b and the upper and lower glass substrates 1
The liquid crystal enclosed between a and 1b and the upper glass substrate 1
It is composed of an upper polarizing plate 1c attached to the outer surface of a and a lower polarizing plate 1d (see FIG. 1) attached to the outer surface of the lower glass substrate. On the opposing surfaces of the upper and lower glass substrates 1a and 1b, transparent segment signal electrode groups and common signal electrode groups are patterned in a direction orthogonal to each other (not shown). The segment signal electrode group is extended to the upper and lower edges of the liquid crystal display panel 1, and the segment driver IC 3 is provided through electrode terminals (not shown) formed at the tip of the segment signal electrode group.
Connected with. The common signal electrode group is extended to the left end side of the liquid crystal display panel 1, and is connected to the common driver IC 4 via an electrode terminal (not shown) formed at the tip of the common signal electrode group. In addition, each signal electrode group and the electrode terminal,
The electrodes are integrally formed by using ITO or the like, and each electrode terminal is formed so as to be exposed to the outside from the edge of the liquid crystal display panel 1.

As shown in FIGS. 1 and 3, the flexible substrate 2 has a predetermined number of lead patterns 12 formed by etching a copper foil on a base film 11 made of, for example, a polyimide film. Each terminal of the segment driver IC 3 or the common driver IC 4 mounted on the flexible substrate 2 is connected to the lead pattern 12. As shown in FIG. 1, the liquid crystal display panel 1 is attached to the molded case 8 on the flexible substrate 2 of this example, the flexible substrate 2 is bent along the side surface of the molded case 8, and the printed wiring board 5a is formed.
When (5b) is disposed on the back surface of the mold case 8, the base film 11 is partially removed and the lead pattern 12 is exposed at a portion substantially corresponding to a corner of the mold case 8. Are formed.

The lead pattern 12 group formed on the flexible substrate 2 and the electrode terminal group formed on the liquid crystal display panel 1 are connected via an anisotropic conductive sheet (not shown). That is, after applying an anisotropic conductive sheet (not shown) to the edge of the liquid crystal display panel 1 where the electrode terminal group is exposed, the electrode terminal group and the lead pattern 12 group are aligned with the edge. In this state, a plurality of flexible substrates 2, 2, ... Are placed side by side, and each flexible substrate 2 is pressed and heated by using a heater chip or the like to solidify the anisotropic conductive sheet. Two
Is fixed to the liquid crystal display panel 1, and the lead pattern 12 group of the flexible substrate 2 and the electrode terminal group of the liquid crystal display panel 1 are connected.

The printed wiring boards 5a, 5b,
A circuit pattern (not shown) for transmitting a signal to each terminal of the driver ICs 3 and 4 of 5c has a method similar to the method of connecting the liquid crystal display panel 1 and the flexible substrate 2 to each other. Lead pattern groups are connected.

The mold case 8 is made of a hard plastic material such as ABS resin or polyethylene, and is formed into a quadrangle having a size such that the liquid crystal display panel 1 and the left printed wiring board 5c can be mounted in parallel. There is. Then, on the liquid crystal display panel mounting surface side, as shown in FIG. 4, a panel mounting base 21 and a substrate mounting base 22 are provided in a protruding manner.
Further, a panel retainer 23 and a substrate retainer 24 for fitting and fixing the liquid crystal display panel 1 or the left printed wiring board 5c on the respective mounting bases are provided around them. A cushion material 21a that is slightly thicker than the height of the panel mounting table 21 is attached to a portion adjacent to the panel mounting table 21. In addition, in the central portion of the substrate retainer 24 protruding along the leftmost end of the molded case 8,
A notch 25 is formed for pulling out the cable 14 connected to the left printed wiring board 5c to the outside, and hooks 26 for locking the left printed wiring board 5c are formed on both sides thereof. There is. Reference numerals 27 and 28 in FIG.
Shows fixed hooks and elastic arms for detachably holding the printed wiring boards 5a and 5b, respectively. These will be described in more detail later.

As shown in FIG. 5, on the back surface of the molded case 8, a print having a depth substantially equal to the thickness of the printed wiring boards 5a and 5b is provided on a portion slightly inside the upper end side and inside the lower end side. The wiring board setting portion 29 is provided as a recess. A plurality of (four in FIG. 5) fixed hooks 27 are formed on one side of the printed wiring board setting portion 29 with their tip portions protruding into the printed wiring board setting portion 29. Further, a plurality of (four in FIG. 5) substantially L-shaped elastic arms 28 are provided on the side opposite to the fixed hooks 27 via the printed wiring board setting portion 29, and the leading end portions thereof are the printed wiring board setting portion 29. It is formed so as to project inward. The elastic arm 28 is formed by cutting out three sides of the molded case 8. When biased in the direction of arrow A, the elastic arm 28 is elastically deformed and its tip is discharged to the outside of the printed wiring board setting portion 29. The tip of the tip returns to the inside of the printed wiring board setting section 29. This elastic arm 2
As shown in FIG. 1, the printed wiring board 5 has
A locking claw 30 is formed to prevent the a and 5b from falling off. Further, a shallow recess 31 for fitting the flexible substrate 2 is provided in a portion from the side surface of the molded case 8 to the printed wiring board setting portion 29 on the back surface.

The method of assembling the liquid crystal display device will be described below. First, as shown in FIG.
A liquid crystal display panel 1 to which printed wiring boards 5a, 5b and 5c are connected via a mold and a mold case 8 formed in the shape shown in FIGS. 4 and 5 are prepared. The liquid crystal display panel 1 is fitted into the panel retainer 23 of the molded case 8,
This is mounted on the panel mounting table 21 via the cushion material 21a. As a result, a direct collision between the liquid crystal display panel 1 and the molded case 8 is avoided, and the liquid crystal display panel 1 is prevented from being damaged. In addition, a space equal to the height of the panel mounting table 21 is formed between the liquid crystal display panel 1 and the molded case 8 so that, for example, a backlight or the like can be stored. Further, the left printed wiring board 5c is fitted in the substrate retainer 24 of the mold case 8, and this is placed on the substrate mounting table 2
Place on top of 2. At this time, the hook 26 formed in the molded case 8 is engaged with a part of the left printed wiring board 5c to prevent the left printed wiring board 5c from falling off. Next, the flexible substrate 2 is bent, and the upper printed wiring board 5a and the lower printed wiring board 5b are brought to the back surface side of the mold case 8. At this time, the flexible substrate 2 is easily bent from the easily deformable portion 13 so that an unreasonable external force does not act on the lead pattern 12 and the like. Next, the elastic arm 28 is pressed by one side of the printed wiring boards 5a and 5b, and this is elastically deformed to provide a space for inserting the printed wiring boards 5a and 5b between the fixed hook 27 and the elastic arm 28. Then, the printed wiring boards 5a and 5b are fitted in the printed wiring board setting unit 29. Thereafter, when the pressing force applied to the printed wiring boards 5a and 5b is removed, the elastic arm 28 returns to the original position direction, and the elastic force moves the printed wiring boards 5a and 5b to the fixed hook 27 side to One side of the plates 5a, 5b is a fixed hook 2
7 is engaged. Along with this, the printed wiring board 5
The other side of a and 5b is engaged with the locking claw 30 of the elastic arm 28, and the printed wiring boards 5a and 5b are elastically held. When the printed wiring boards 5a and 5b are removed, the printed wiring boards 5a and 5b are pressed toward the elastic arm 28 side and elastically deformed so that the printed wiring boards 5a and 5b are placed between the fixed hook 27 and the elastic arm 28. Open a space for discharge. Then, the fixed hook 27 side of the printed wiring boards 5a and 5b is lifted up, and the other side is removed from the locking claw 30 of the elastic arm 28.

The elastic arm 2 is used in the above embodiment.
Although 8 is formed in a substantially L shape, it may be formed in a linear shape as shown in FIG. In addition, the shape of the elastic arm can be arbitrarily formed regardless of the above embodiment.

[0021]

As described above, according to the present invention,
Since the setting part of the printed wiring board is recessed in the mold case, it is possible to reduce the total thickness of the liquid crystal display device, and since the fixing hook and the elastic arm are provided in the mold case itself, the device cost is high. It does not become heavy or heavy.
Further, since the printed wiring board is snap-fitted by the fixed hook and the elastic arm, the assembling / disassembling property is remarkably improved. In addition, since an easily deformable portion is provided in a part of the flexible board, the flexible board is bent from the liquid crystal display panel mounting surface side of the mold case to the back surface side, and the printed wiring board is arranged on the back surface side of the liquid crystal display panel. Therefore, the liquid crystal display device can be downsized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of a liquid crystal display device according to a first embodiment.

FIG. 2 is a development explanatory diagram of a liquid crystal display device on which a printed wiring board and a flexible substrate are mounted.

FIG. 3 is an enlarged plan view of a flexible substrate.

FIG. 4 is a plan view of the mold case according to the first embodiment.

FIG. 5 is a back view of the mold case according to the first embodiment.

FIG. 6 is a rear view of the mold case according to the second embodiment.

[Explanation of symbols]

 1 Liquid Crystal Display Panel 2 Flexible Boards 5a, 5b, 5c Printed Wiring Board 7 Connection Cable 8 Mold Case 11 Base Film 12 Lead Pattern 13 Easy Deformation Part 27 Fixed Hook 28 Elastic Arm 29 Printed Wiring Board Setting Section

Claims (1)

Claims: 1. A mold case molded of a plastic material, a liquid crystal display panel mounted on one side of the mold case, a printed wiring board on which a necessary circuit pattern is formed, and A different lead pattern is formed, a driver IC is mounted on the lead pattern, and a signal electrode group formed on the liquid crystal display panel and a circuit pattern formed on the printed wiring board are formed through the lead pattern. In a liquid crystal display device including a flexible substrate electrically connected, a setting portion of the printed wiring board is recessed on the back surface side of the liquid crystal display panel mounting surface of the mold case, and on both sides of the setting portion via the setting portion. A fixing hook for detachably holding the printed wiring board and an elastic arm are arranged to face each other, and To allow the folding of the flexible substrate provided with a readily deformable portion in a part of the substrate, a liquid crystal display device being characterized in that snap mounted between the printed circuit board the fixing hook and the elastic arm.