JPH0755542Y2 - Liquid crystal display - Google Patents

Description

TECHNICAL FIELD The present invention relates to a liquid crystal display device.

2. Description of the Related Art Conventionally, as a mounting structure of a liquid crystal display device, for example, Japanese Patent Laid-Open No.
There is one as shown in Japanese Patent Publication No. 62-205389. Fourth
The figure shows the outline. First, the scanning signal extracting electrode portion 2 on the lower substrate of the liquid crystal display element 1 using the glass substrate to which the polarizing plate is attached, and the driving LSI on the back surface (lower surface).
Electrical connection is made by thermocompression bonding at both ends of the flexible printed circuit board 5 to the anisotropic conductive film 4 for scanning signals of the hard printed circuit board 3 such as a glass epoxy substrate on which is mounted. Next, while inserting the anisotropic conductive rubber 7 between the data signal extracting electrode portion 6 formed on the lower surface of the upper substrate of the liquid crystal display element 1 and the data signal connecting electrode portion of the hard printed board 3, Align them and temporarily fix them. Then, the claw portion 9 of the bezel 8 is inserted into the positioning hole 10 of the rigid printed circuit board 3, and the anisotropic conductive rubber 7 is pressed between the liquid crystal display element 1 and the rigid printed circuit board while pressing the liquid crystal display element 1. To establish electrical continuity. After that, the claw portion 9 of the bezel 8 is
Fix it by twisting it as shown in FIG.

Problems to be Solved by the Invention According to such a conventional mounting structure, in the liquid crystal display element 1, the extraction electrode portions 2 and 6 are turned upside down, and the connection surfaces do not match. The substrate 3) and the liquid crystal display element 1 are connected by the anisotropic conductive rubber 7 on the data signal electrode side and the flexible substrate 5 and the anisotropic conductive film 4 on the scanning signal electrode side, and the number of parts is large, and , There are many connection points. This allows
Along with the high cost, the connection workability is deteriorated.
Further, as a backlight, an EL backlight is inserted between the liquid crystal display element 1 and the hard printed circuit board 3, and there is an inconvenience that a cathode tube type backlight cannot be used.

Means for Solving the Problems In a liquid crystal display device having a liquid crystal display element and a drive circuit board for the liquid crystal display element, the drive circuit board is provided with a data signal connection electrode section and a scanning signal connection electrode section for the liquid crystal display element. As a flexible printed circuit board integrally formed on the same surface, one connection electrode portion of the data signal connection electrode portion and the scanning signal connection electrode portion of the flexible printed circuit board is folded back once and the other electrode portion is doubled. After diffraction, the liquid crystal display element is directly connected to each extraction electrode portion by thermocompression bonding of an anisotropic conductive film.

In the liquid crystal display element, the data signal extracting electrode portion and the scanning signal extracting electrode portion are located on different surfaces, but as the drive circuit board, the data signal connecting electrode portion and the scanning signal connecting electrode portion are integrally formed on the same surface. By using the formed flexible printed circuit board, by devising the folding back of these electrode parts,
For the liquid crystal display element, only thermocompression bonding with an anisotropic conductive film is required. Therefore, the number of parts is reduced, and the cost such as initial cost can be reduced. Further, the number of connecting points is reduced, so that the connecting process can be saved. Further, the positioning of the electrode portions when connecting and fixing is facilitated by the flexibility of the flexible printed circuit board.

Embodiment An embodiment of the present invention will be described with reference to FIGS. First, the upper substrate 11 and the lower substrate 12 are provided, and both substrates 11, 1
A liquid crystal display element 13 having a liquid crystal (not shown) held between the two is provided. Here, for example, a data signal extracting electrode portion 14 is formed on the lower surface end portion of the upper substrate 11, and a scanning signal extracting electrode portion 15 is positioned on the upper surface end portion of the lower substrate 12 in a direction orthogonal to the electrode portion 14. Has been formed.

Thus, the liquid crystal driving LSI 16, the power supply circuit 17, etc. are mounted only on one side of the back surface (the surface opposite to the liquid crystal display element 13), and further, the drive circuit board 19 having the controller connector 18, etc.
Is provided. The drive circuit board 18 is made of a flexible printed board, and the data signal connection electrode section 20 is connected and fixed to the data signal extraction electrode section 14 and the scanning signal extraction electrode section 15 of the liquid crystal display element 13 by thermocompression bonding,
The scanning signal connection electrode portion 21 is integrally formed. More specifically, as shown in FIG. 2 which is an exploded view, for example, the data signal connection electrode portion 20 is normally formed at one end of the back surface of the flexible printed board 18, and the outer bent portion 22 is formed.
It is formed so as to face the data signal connection electrode portion 20 of the liquid crystal display element 13 by returning once. On the other hand, the other scanning signal connecting electrode portion 21 is formed at the front end of the back surface of the protruding portion 23 that largely protrudes from the liquid crystal display size portion of the flexible printed circuit board 18 in a substantially L shape (orthogonal to the data signal connecting electrode portion 20). Direction)
It was done. Bent portions 24 and 25 are set at two places in such a protruding portion 23. First, when the protruding portion 23 is bent once at the outer bending portion 24 along the device size portion, it becomes a state of substantially overlapping on the device size portion on the surface side,
In addition, the scanning signal connection electrode portion 21 is located upwardly at a position protruding from the device size portion (position on the side opposite to the controller connector portion 17 and orthogonally adjacent to the data signal connection electrode portion 20). Therefore, this time, the second bending is performed by the inner bent portion 25, so that the scanning signal connection electrode portion 21 is directed downward and can be positioned on the scanning signal extraction electrode portion 15 of the lower substrate 12.

More practically, as shown in FIG. 1, on the surface of the flexible printed circuit board 19, the protruding portion is formed by the outer bent portion 24.
After bending 23, a spacer member 26, which is approximately U-shaped in the size of the apparatus, is interposed. In this state,
By bending at the outer bending portion 22, the data signal connection electrode portion 20 is positioned on the spacer member 26 and faces the data signal extraction electrode portion 14 of the upper substrate 11 of the liquid crystal display element 13. Therefore, electrical continuity is secured by aligning these electrode portions 20 and 14 and fixing them by thermocompression bonding through the anisotropic conductive film 27. On the other hand, with respect to the scanning signal connection electrode portion 21 side, by performing the second bending at the inner bent portion 25, the scanning signal connection electrode portion 21 is located above the spacer member 26 and the electrode surface faces downward. . Therefore, the lower substrate 12 of the liquid crystal display element 13 placed on the spacer member 26.
The electrical conduction is also secured by aligning on the scanning signal extracting electrode portion 15 on the upper surface and fixing by thermocompression bonding through the anisotropic conductive film 28. A dispersed EL backlight 29, for example, is inserted in the space of about 1.5 mm between the liquid crystal display element 13 and the flexible printed board 19 formed by the spacer member 26 (see FIG. 3).

As described above, according to this embodiment, the data signal connection electrode portion 20
The flexible printed board 19 in which the scanning signal connection electrode portion 21 and the scanning signal connection electrode portion 21 are integrally formed is used.
By devising the folding of 20 and 21, it is only necessary to perform thermocompression bonding to the liquid crystal display element 13 using the anisotropic conductive films 27 and 28, the number of parts is reduced, and cost such as initial cost is reduced. be able to. Further, the number of connecting points is reduced, so that the connecting process can be saved. Moreover, the flexibility of the flexible printed board 19 facilitates the alignment of the electrode parts when connecting and fixing. Further, even a cathode ray tube type backlite that could not be used conventionally can be obtained by increasing the height of the spacer member 26.

When configuring the present embodiment, when designing the circuit pattern, taking into account the relative positions of the extraction electrode portions 14 and 15 of the liquid crystal display element 13 and the connection electrode portions 20 and 21 of the flexible printed board 19, the alignment accuracy is considered. It needs to be well designed. Further, as the liquid crystal driving LSI 17, a flat package type is generally used, but since the board area and the weight increase as the capacity becomes higher, if the LSI chip is wire-bonded and mounted by TAB, etc., The size, thickness and weight can be reduced. Further, by forming the controller connector portion 18 to the controller portion side integrally with the flexible printed board 19, the drive circuit board can be further simplified. In particular, the flexible printed circuit board 19 is provided for the effective display area of the liquid crystal display device.
There is almost no protrusion to the outside of the device, and the size of the device is reduced as a whole.

In the present embodiment, the flexible printed board 19 is configured such that the scanning signal connection electrode portion 21 side is returned twice and the data signal connection electrode portion 20 side is returned once, but the electrode portion 14 on the liquid crystal display element 13 side, It is determined by the relationship with the position of 15. On the contrary, the scanning signal connection electrode portion 21 side is returned by one diffraction,
In some cases, it may be better to configure the data signal connection electrode section 20 side to return twice.

In addition, in the configuration of the present embodiment described above, the liquid crystal display element
As the substrate 13, a flexible liquid crystal display element in which the substrates 11 and 12 are flexible film substrates is used, and EL back light is used.
After arranging a curved reinforcing member having a predetermined curvature on the lower side of 29, the EL back light 29 and the flexible printed circuit board 19
If it is fixed by adhesion, it will be very thin and lightweight, and it will be possible to support curved surface display.

In addition, in the configuration of the present embodiment described above, the spacer member
In place of the 26 and EL backlight 29, a thin aluminum plate having a thickness of about 0.5 mm is arranged, and the extraction electrode portions 14 and 15 of the liquid crystal display element 13 and the connection electrode portions 20 and 21 of the flexible printed circuit board 19 are connected. Each is connected as described above. A polarizing plate with a reflector is used as the lower polarizing plate of the liquid crystal display element 13. According to this, further reduction in thickness and weight can be achieved, and a low cost reflective liquid crystal display device can be obtained.

As illustrated in these examples, there is a large degree of freedom with respect to various forms such as a transmissive type or a reflective type using an EL back light or a cathode ray tube type back light, or a curved surface display method.

Advantageous Effects of Invention The present invention provides a flexible printed circuit board in which a data signal connection electrode part and a scanning signal connection electrode part for a liquid crystal display device are integrally formed on the same surface as described above. One of the data signal connection electrode portion and the scanning signal connection electrode portion is returned by one diffraction return of the other electrode portion, and the other electrode portion is returned by two diffraction reflections of the anisotropic conductive film on each extraction electrode portion of the liquid crystal display element. Since they were directly connected by thermocompression bonding, a flexible printed circuit board on which the data signal connection electrode part and the scanning signal connection electrode part were integrally formed on the same surface was used as the drive circuit board. By devising the above method, it is only necessary to perform thermocompression bonding with the liquid crystal display element using an anisotropic conductive film, thus reducing the number of parts and reducing costs such as initial costs. In addition, the number of connection points can be reduced, and the connection process can be saved.In addition, the positioning of the electrodes during connection and fixing is facilitated by the flexibility of the flexible printed circuit board, and there are no restrictions such as backlights. The degree of freedom with respect to various types of liquid crystal display devices is increased.

[Brief description of drawings]

1 is an exploded perspective view showing an embodiment of the present invention, FIG. 2 is a bottom development view of a flexible printed circuit board, FIG. 3 is an assembled side view, and FIG. 4 is an exploded perspective view showing a conventional example. 5
The figure is a partial perspective view of the assembled state. 13 …… Liquid crystal display device, 14, 15 …… Extraction electrode part, 19 ……
Flexible printed circuit board, 20 ... Data signal connection electrode section, 21 ... Scanning signal connection electrode section, 27,28 ... Anisotropic conductive film

Claims (1)

[Scope of utility model registration request] 1. A liquid crystal display device having a liquid crystal display element and a drive circuit board for the liquid crystal display element, wherein the drive circuit board has the same data signal connection electrode section and scan signal connection electrode section for the liquid crystal display element. A flexible printed circuit board integrally formed on a surface of the flexible printed circuit board. One of the data signal connection electrode section and the scanning signal connection electrode section of the flexible printed circuit board is returned by one turn and the other electrode section is returned by two turns. The liquid crystal display element is characterized in that it is directly connected to each extraction electrode portion of the liquid crystal display element by thermocompression bonding of an anisotropic conductive film.