JPS60208734A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain the liquid crystal display device of small-area, thin structure by arranging an LSI for driving liquid crystal at right angles to a liquid crystal display panel by utilizing tape automated bonding (TAB) technique. CONSTITUTION:The LSI63, 64 for liquid crystal drive such as signal electrode drive and scanning electrode drive is mounted by utilizing the TAB technique; these LSI are mounted on projections 53 and 56 of an FPC substrate 51 by face- up bonding and on the remaining projections 54 and 52 by face-down bonding. Thus, the TAB technique is utilized to mount LSIs and when it is mounted on the FPC substrate 51, the length of one side is about 10mm.. Consequently, the projection parts 53, 54, 55, and 56 of the FPC substrate 51 are bent and the LSIs for liquid crystal drive are arranged on the flanks of the frame 58, there is an enough space for storage. Thus, the liquid crystal display device with small area and small thickness is obtained.

Description

[Detailed description of the invention] Technical fields> The present invention relates to a mounting form of a liquid crystal display device.

Technical Background In today's information society, it is necessary to be able to obtain various types of information quickly and accurately, and personal information devices are attracting attention as a means of achieving this.

Personal information devices are required to be driven at low voltage, consume low power, and be light, thin, short, and small in a variety of shapes. There is an IJ type liquid crystal display device that relatively satisfies these requirements, and research and development is being carried out in various fields. In particular, reports regarding LCD color televisions are actively published in technical magazines such as the 9-character society magazine.

<Prior Art> There are two types of matrix panels for color LCD televisions: active matrix type and simple matrix type.

In an active matrix liquid crystal display panel, a plurality of signal electrodes and a plurality of scan electrodes are arranged in a matrix, and switching transistors and liquid crystal drive electrodes are formed at the intersections of these electrodes to form pixels. An image is displayed by the switching transistor selecting an arbitrary pixel in response to an external signal, and the voltage applied to each liquid crystal drive electrode is statically applied to the liquid crystal. On the other hand, in the case of a simple matrix liquid crystal display panel, a plurality of signal electrodes are formed on one of nine overlapping glass substrates, and a plurality of scanning electrodes are formed on the other glass substrate, and both electrodes are arranged in a matrix. be done. An image is displayed by selecting an arbitrary pixel using an external signal, and the pixel at the intersection of each electrode is dynamically driven.

In either case, the signal electrode and the scanning electrode are drawn out to the outer periphery of the pixel area and connected to the output terminal of the LSI. Furthermore, it is essential to use color filters, the panel structure must be of a transmissive type, and a light source such as a fluorescent lamp must be installed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a conventional form of a liquid crystal display module including a substrate mounting an LSI for driving pixels of a color liquid crystal active matrix and an LSI will be described with reference to the drawings.

(1) FIG. 1 shows a first form of the liquid crystal display module.

A wiring area in which wiring electrodes 4 are formed is provided on the outer periphery 3 of the pixel area 2 of the liquid crystal display panel 1, and a liquid crystal driving LSI 5 is die-bonded directly onto the panel 1. Each input/output wiring and the pad of the LSI 5 are connected by wire 6 by bonding.

In this structure, a wiring area and an LSI mounting area for driving each pixel electrode 7.8 are formed in the pixel area outer periphery 3 of the liquid crystal display panel 1, and an area is further connected to an external circuit for supplying input signals to the LSI 5. 9 must be formed. Therefore, the liquid crystal display panel 1 becomes larger than the pixel area 2. In addition, the LSI mounting area is the pixel area 2.
The input signal line portion of LSI 5 must be formed on the same glass surface as the LSI 5, and multilayer wiring must be formed.
No. 5 has the disadvantage that the yield rate as a liquid crystal display module is considerably low because it is only tested on a wafer and there is a possibility that defects may be mixed in.

(2) A second form of the same module is shown in FIG.
16 is die-bonded and wire-bonded and connected to the liquid crystal display panel 12 by solder connection or an anisotropically conductive rubber connector 15. In this structure, LSI
16 is mounted on the rigid substrate 11, the dimensions of the liquid crystal display panel 12 are the same as those of the pixel area 17 and the rigid substrate 11.
Since the liquid crystal display panel 12 is relatively small, the yield is improved. However, the above (1
), this method has the disadvantage that an extra connection area 15 between the rigid substrate 11 and the liquid crystal display panel 12 is required, resulting in a larger area for the liquid crystal display module. Similar drawbacks arise even when a flexible substrate is used instead of a rigid substrate.

(3) FIG. 3 shows a third form of the module.

The following method has been proposed as a means to reduce the area of a liquid crystal display module. Flexible wiring board 2
1 (abbreviated as FPC board), and the LSI 22 mounted in a flat package is placed on the bottom surface 2 of the FPC board.
3, and connect the FPC board 21 to the liquid crystal display panel 25 using the anisotropically conductive rubber connector 24. In this case, in order to reduce the size of the liquid crystal display module, it is customary to bend the FPC board 21 from the vicinity of the connection part with the liquid crystal display panel 25 so that the area of the bottom surface 23 is approximately the same size as the liquid crystal display panel. However, a flat socket has a large area and uses a single board for signal driving LS1. It is impossible to mount all of the scanning drive LSIs, and a separate substrate 26 is required, which has the disadvantage of increasing the module thickness.

Furthermore, even if the module could be mounted on a single board, the LSI would be placed after the light source 27, which would inevitably increase the module thickness considering the thickness of the flat package.

<Object of the Invention> The present invention has been made to solve the above-mentioned drawbacks of the conventional color liquid crystal display device.
An object of the present invention is to provide a liquid crystal display device having a small area and thin structure by mounting a liquid crystal driving LSI on the side surface of a PC board.

<Embodiment> FIG. 4(G) is a configuration diagram of a liquid crystal display device showing one embodiment of the present invention, and FIG. 4(B) shows the configuration of the liquid crystal module mounting board of FIG. 4(5). FIG.

The flexible FPC board 51 has a bottom surface 52 and 4 parts around the bottom surface.
It is formed into a cross shape having convex portions 53 to 56 in the direction. If necessary, a rigid reinforcing plate may be adhesively fixed to the bottom surface 52 and some of the convex portions 53 to 56 in the four directions. For example, a wiring board 61 for a control circuit is mounted on the bottom surface 52.
For example, wiring electrodes 62 of a liquid crystal drive circuit are formed on the protrusions 53 to 56, and electrodes for connection with a liquid crystal display panel 57 are formed on the tips 62' of the protrusions in four directions. The LSIs 63 and 64 for driving liquid crystals, such as driving signal electrodes and scanning electrodes, are mounted using tape automation bonding (TAB) technology, and the protrusions 53 and 56 of the FPC board 51 are mounted using face-up bonding ( or face-down bonding), and is mounted on the other convex portions 54 and 55 by face-down bonding (or face-up bonding). The control circuit LSI 65 mounted using the bottom surface 52 may be mounted by face amplifier bonding or face down bonding. LSI63.64 for LCD drive, LSI for control circuit
65 and the FPC board 51 on which the chip component 59 fixed to the bottom surface 52 is mounted is bent along the frame 58. By providing an opening or a recess 60 in the side wall surface of the frame 58 where the LSI 63, 64.65 and the chip component 59 are arranged, the LSI 63, 64.65 and the chip component 59 are housed in the opening or the four parts 60. and is prevented from directly contacting the frame 58. F
The electrode portion 62' for connecting the liquid crystal display panel of the PC board 51 is further bent along the frame 58, and the liquid crystal display panel 5 is
Connect with 7. This connection may be made using an anisotropic conductive rubber connector or a hot melt adhesive. Further, they may be connected by soldering or may be used in combination. When implementing LSI, use TA as described above.
B technology is used, and the length of one side when mounted on the FPC board 51 is 10 mm or less.

On the other hand, when a light source 100 such as a fluorescent lamp is disposed on the back side of the liquid crystal display panel 57, the thickness of the light source 100 is also about 10 Wa. Therefore, the protrusions 53 and 54 of the F'PC board 51
, 55, 56 are bent and a liquid crystal driving LSI is arranged on the side surface of the frame 58, there is still enough space to accommodate the liquid crystal driving LSI. In this embodiment, the LSI was mounted using TAB technology, but wire bonding may be used instead.
Beam leads or slip tips may also be used.

In this example, the convex parts around the FPC were made in four directions, but three
It goes without saying that it may be in one direction or in two directions.

<Effects of the Invention> As explained in detail above, according to the present invention, the LSI for driving the liquid crystal is arranged perpendicularly to the liquid crystal display panel using direct bonding technology such as TAB technology. This solves the problem of arranging the LCD module on the same plane as the pixel area, which required a large space, and also solved the problem of increasing the depth of the LCD module by placing the LCD drive LSI at the bottom of the LCD panel. resolved. Furthermore, the area can be made very small, and a liquid crystal display module with a thin depth can be obtained.

[Brief explanation of drawings]

FIGS. 1 to 3 are explanatory diagrams showing the mounting form of a conventional liquid crystal display module. FIG. 4(A) is a configuration diagram of a liquid crystal display device showing one embodiment of the present invention, and FIG. 4(B) is a plan view showing the configuration of a liquid crystal module mounting board of the liquid crystal display device. ...FPC board 52...Bottom surface 53,54°5
5.56...Convex portion 57...Liquid crystal display panel 58.
... Frame 59 ... Chip parts 61 ... Wiring electrodes 63, 64 ... LSI for liquid crystal drive 65 ... LSI for control circuit

Claims (1)

[Claims] 1. In a liquid crystal display device comprising a transmissive liquid crystal display panel having a light source, an LSI for driving the panel, and a substrate on which the LSI is mounted, the substrate is replaced by a flexible substrate having a convex portion on the same side. A liquid crystal display device comprising: the LSI is directly mounted on the convex portion, and the convex portion is arranged substantially perpendicular to the panel in correspondence with the depth range of the light source.