JPS5922087A - Terminal connection of matrix type display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a terminal connection method in a high-density information display device having orthogonal strip-shaped electrodes, a so-called matrix type electrode structure.

In a matrix type display device such as a liquid crystal display device, a plasma display device, or an EL display device, the display density increases as the number of rows (number of scanning lines) increases.
Although the display quality is improved, the time during which a signal is applied per row, that is, the duty, is reduced, and the margin for crosstalk is reduced. In particular, when a liquid crystal is used as a display element, it is difficult to obtain sufficient contrast in a high-density liquid crystal display device because the transmittance-voltage characteristics of the liquid crystal are not steep and the response is slow. Therefore, the following measures have been proposed to solve these problems.

■Development of liquid crystal materials with clear threshold characteristics.

(2) Increasing the driving force 7 (a = Von/Vo [f) by optimizing the matrix addressing method.

■ Improve the apparent resolution by devising the electrode structure.

For example, as shown in FIG. 1(a), the signal electrode is placed on the upper side Y1.
．． Y2.・------, Y n and lower Yt, Y
'2.

. . . Y2, scanning electrodes X1 . X2.・
・・・・・・．

XIn is made common to the two side signal electrodes and the lower side signal electrode. In addition, as shown in Figure 1 (1)), one scanning electrode Xi
A signal electrode Yj adjacent to the signal electrode Yj.

Insert Y11□ in a comb shape. The other is a liquid crystal panel including a scanning electrode 2 and a signal electrode 3 between glass substrates 1 and 4, and a scanning electrode 2' and a signal electrode 3 between glass substrates 1' and 4, as shown in FIG. This is a method in which the liquid crystal panels including the liquid crystal panels are combined using a common glass substrate 4, and each liquid crystal panel is driven separately.

In the method of (0) and (2), there is no need to change the structure 41 of the liquid crystal panel, and it cannot be expected to dramatically increase the number of lines that can be driven (i+J). On the other hand, although the method (2) complicates the structure of the liquid crystal panel, it can reliably increase the number of lines that can be driven by twice, 22 times, and so on. With the method (2), the number of lines that can be driven can be greatly increased, and the number of signal electrode end electrodes can also be doubled, 22 times...
・It increases. A method for mounting a crystal panel with a large number of connection terminals is to use a film wiring board to connect the terminal electrodes on the signal side and scanning side of the liquid crystal panel and the wiring board on which the drive circuit elements are mounted. There is a way. This type of method has the following drawbacks.

■ Difficult to interact with the LCD display panel.

■ Is it necessary to form a parent solder metal on the terminal part in advance?

■ When hanging, the connection part becomes hot or there is a difference in elongation due to the difference in thermal expansion coefficient between the film wiring board and the glass, so a connection method that takes this into consideration is required.

■ The number of connection points increases, leading to an increase in man-hours.

■ A film wiring board with high-density wiring is required;
Such film wiring boards are expensive.

■ The film wiring board is bent and mounted, resulting in wasted space.

■ It is difficult to make it thinner because it requires multiple wiring boards.

Among these, ■ to ■ are factors that increase costs, and ■ and ■
This poses a major obstacle to miniaturization and thinning of liquid crystal display devices.

As a method to eliminate all of these drawbacks, a mounting method has been considered in which the edges of the wiring board on which the liquid crystal drive circuit is mounted are bent and electrical connection is made with the liquid crystal panel using conductive rubber. By the way, a normal liquid crystal display panel has a third
As shown in the figure, signal electrodes 3 and scanning electrodes 2 are formed inside glass substrates 4 and 5, respectively.
Generally, the scanning electrode 2 and the scanning electrode 2 are not on the same plane.

6 is a liquid crystal, and 7 is a sealing resin.

When applying the mounting method described in "-" to such a liquid crystal panel, the scanning electrode 2 is made of conductive silver (A) as shown in FIG.
g) Is it necessary to transfer to the signal side glass substrate 4'2 using a transfer material 8 such as a paste and form the terminal electrode on the same plane as the signal electrode 3?

However, this transfer has the following problems.

■ An area on the glass is required for the transition, which is contrary to miniaturization.

■ There are two problems: the process of performing transfer increases and the cost increases.

(2) Due to the difference in thermal expansion coefficient between the sealing resin 7 and the transfer material 8, peeling occurs at the interface between the glass substrates 4, 5 and the transfer paulownia material 8, resulting in poor conduction and reliability.

Therefore, as a method of connecting the liquid crystal panel and the wiring board to perform electrode transfer, as shown in FIG. Then, the signal side edge 14 of the wiring board 11 is connected to the terminal electrode of the signal electrode 3 of the liquid crystal panel via the anisotropically conductive rubber 9, and the wiring board 1 is connected via the anisotropically conductive rubber 9 to the terminal electrode of the signal electrode 3 of the liquid crystal panel.
A method has been considered in which the scanning side edge 15 of the liquid crystal panel 1 is connected to the terminal electrode of the scanning electrode 2 of the liquid crystal panel. Reference numeral 10 denotes a clamping body that fixes the liquid crystal panel and the wiring board 1-1.

However, there is still room for improvement in this method as described below.

(2) Since it is necessary to bend the scanning side edge 15 of the wiring board 11 in the opposite direction to the signal side edge 14, the bending process becomes two steps, making the process complicated and increasing the cost.

■ Scanning side edge 1 of scanning side glass substrate 5 and wiring board 11
It is not easy to insert the anisotropically conductive rubber 13 between the conductive rubber 13 and the anisotropically conductive rubber 13.

Such problems are not limited to liquid crystal display devices, but similar problems occur when connecting terminals in plasma display devices, EL display devices, and the like.

The present invention solves these problems, uses the conventional display panel structure as is, and is simple and easy to assemble.
M) The purpose of this method is to provide a terminal connection method for an IJ sock display device, which connects at least one edge of a wiring board extending from a drive circuit to a display panel. Fold it in the direction of proximity, make one terminal electrode of the display panel and the bent edge of the wiring board face each other, and electrically connect them via an anisotropically conductive member such as anisotropically conductive rubber. At the same time, by electrically connecting the other terminal electrode of the display panel to the other side of the wiring board and the recording edge through an anisotropic aluminum outer material such as a bent anisotropic conductive rubber. The aim is to achieve the following objectives.

An example in which the present invention is applied to a liquid crystal display device will be described below.

As shown in FIG. 6, a liquid crystal display in which a signal electrode 3 and its terminal electrode 3 are formed inside a signal-side glass substrate 4, and a scanning electrode 2 and its terminal electrode 2' are formed inside a scanning-side glass substrate 5. For the panel, this liquid crystal panel drive circuit 12
As shown in the figure, a wiring board 11 with the edges 14 and 15, on which the output wiring of the drive circuit 12 is mounted and many terminals are arranged, are bent in the same direction. .The terminal electrodes 3 of the signal electrodes 3 facing each other
The terminal electrode 3' is wired by interposing an anisotropically conductive rubber 9 having conductivity in one direction (two downward directions in the figure) between the terminal electrode 3' and the terminal on one edge 14 of the wiring board 11. Board 1
There is a unidirectional connection between the terminal electrode 2' of the scanning electrode 2 and the terminal of the other edge 15 of the wiring board 11, which are electrically connected to the corresponding terminals on the edge 14 of the wiring board 1 and located in the same direction. The terminal electrodes 2' are electrically connected to the corresponding terminals on the edge 15 of the wiring board 11 by intervening a U-shaped bent anisotropic conductive rubber 16 having conductivity. After that, the liquid crystal panel and the wiring board 1 are held together by the clamping body 10.
1 and fixed.

In this embodiment, the edge of the wiring board 11 includes not only the edge 14 connected to the terminal electrode 3' of the signal electrode 3 but also the edge 14 connected to the terminal electrode 2' of the scanning electrode 2 on the display panel. Since it is bent to the side, it is possible to reduce not only the resistance value of the anisotropic conductive rubber 9 but also the resistance value of the bent anisotropic conductive comb 16.
The connection between the terminal electrode 2' and the edge 15 can also be made with high precision.

As the thickness of the drive circuit element 12 on the wiring board 11 becomes thinner, the distance between the wiring board 11 and the scanning side glass substrate 5 of the liquid crystal panel can be narrowed.
It is not necessary to bend the scanning side edge 15 of the wiring board 11 on the scanning side without increasing the resistance of the bent anisotropic conductive rubber 16 as shown in FIG. The edge portion 15 can be connected to the terminal electrode 2' of the scanning electrode 2 of the liquid crystal panel.

Here, as shown in FIG. 8, the anisotropically conductive rubber 9 is alternately laminated with conductive layers 17 and insulating layers 18, and the repeating pitch of the conductive layers 17 is set at the terminal electrode 3' of the signal electrode 3.
It is possible to use an arrangement pitch that matches the arrangement pitch of the terminals on the edge 14'' of the substrate 11.

Further, the bent anisotropic conductive comb 16 may be formed by alternately laminating conductive layers 17 and insulating layers 18 and bending or molding them into a U-shape, as shown in FIG. What can you use?

In this case as well, the repeating pitch of the conductive layer 17 is the pitch of the terminal electrodes 2' of the scanning electrode 2 and the edge 151 of the substrate 11.
matches the pitch of the terminals.

Further, as another example of the bent anisotropic conductive comb, a '-shaped one 21 in which a thin metal wire 19 is sandwiched between insulating combs 20 as shown in FIG. 10 can be used. To use this anisotropic conductive rubber 21, as shown in FIG. 11 or FIG. The other end may be brought into contact with the second terminal on the edge 15'' of the wiring board 11.

This anisotropically conductive rubber 21' is used as a conductor with thin metal wires 19.
11 or 12, whether the edge of the wiring board 11 5 is bent or not, the connection resistance does not increase. Can be connected, once the driving circuit element)
The connection can be made almost unaffected by the thickness of 12.

Still another example of the bent anisotropic conductive comb is the 13th
As shown in the figure, a circuit pattern 24 was printed using conductive ink or conductive paste on one surface of an anisotropic conductive rubber in which a large number of conductive thin wires 23 were embedded in the thickness direction of an insulating rubber 22. The material 25 may be used by being bent between the terminal electrode 2' of the scanning side electrode 2 and the edge 15 of the wiring board 11 as shown at 25' as shown in FIG. In this case, it is possible to make the thickness of the anisotropic conductive comb thinner than that described above, for example, the thickness of the rubber can be made 0.2 mm.
Since it can be done to a certain degree, if the drive circuit element 12 is inserted into the recess 26 of the wiring board as shown in FIG. It is possible to construct a display device that is thinner than the display device of the embodiment described in ij.

The above description has been made on the assumption that the scanning side glass substrate 5 is located at the bottom of the liquid crystal panel, but it goes without saying that the scanning side glass substrate 5 and the signal side glass substrate 4 may be interchanged. However, in the case of a liquid crystal panel, the scanning electrode pitch is larger than the signal electrode pitch.
The above embodiment is better because the alignment between the scanning side terminal electrode 2' and the terminal on the substrate edge 15 is automatically performed. preferable.

The above embodiments relate to a liquid crystal display device, and the present invention relates to a method for connecting terminals, and is applicable not only to liquid crystal display devices but also to matrix phase flat displays such as plasma display devices and E-I display devices. It is commonly applied to all devices, and the present invention also includes application to devices other than liquid crystal display devices.

In the present invention, among the edges of the wiring board on which the driving circuit elements are mounted, at least the edge having the terminals to be connected to the electrodes formed on the front glass substrate of the display panel is bent, and the display panel and the wiring board are separated. Since the configuration I is configured such that the anisotropically conductive member and the bent anisotropically conductive member are electrically connected to each other, the following effects can be achieved.

(1) There is no need to transfer the electrodes from the glass substrate on the back side (for example, the glass substrate on the scanning side) to the glass substrate on the front side (for example, the glass substrate on the signal side), and the electrodes can be transferred directly from the glass substrate on the back side to the wiring board. can be connected to.

(2) If the terminal electrode of the signal electrode and the terminal on one edge of the wiring board are aligned correctly, there is no need to align the terminal electrode of the scanning electrode and the terminal on the other edge of the wiring board. If bent anisotropically conductive members are also used with a minute pitch, the process of connecting the anisotropically conductive members becomes very easy.

(3) The anisotropic conductive member for signal electrode connection and the anisotropic conductive member for scan electrode connection can be inserted at the same time.

In this way, it has become possible to easily and accurately connect the fine-pitch electrodes of the display panel to the fine-pitch ends r of the wiring board.

[Brief explanation of the drawing]

Figure 1 (a) is a schematic diagram showing the upper and lower electrode division method in the liquid crystal panel, Figure 1 (13) is a schematic diagram showing the double electrode system in the liquid crystal panel, and Figure 2 is the schematic diagram showing the dual electrode system in the liquid crystal panel.
A cross-sectional view showing the layer system, Figure 3 is a cross-sectional view showing the structure of a normal liquid crystal panel, Figure 4 is a cross-sectional view showing a liquid crystal panel with electrode transition, and Figure 5 shows an improved terminal connection method. 6 and 7 are cross-sectional views showing embodiments of the present invention, FIG. 8 is a perspective view showing an example of anisotropically conductive rubber, and FIG. 9 is a cross-sectional view showing an example of anisotropically conductive rubber bent. FIG. 10 is a perspective view showing another example of bent anisotropically conductive rubber in a state before bending, and FIGS. 11 and 12 are
A sectional view showing an example using the anisotropically conductive rubber shown in Figure 0,
FIG. 13 is a perspective view showing still another example of the bent anisotropically conductive rubber in a state before bending, and FIG. 14 is a sectional view showing an example using the anisotropically conductive rubber shown in FIG. 13. . However, in Figures 5, 6, 7, 11, 12, and 14, the left side is a cross-sectional view taken parallel to the signal electrode, and the right side is a cross-sectional view taken parallel to the scanning electrode. It represents. 2... Scanning electrode, 3... Signal electrode, 4.5... Glass substrate, 9, 13... Anisotropic conductive comb, 11...
Wiring board, 14.15... Edge of wiring board, 16.2
1'. 25'...Bent anisotropically conductive rubber. Special r “Applicant: Sharp Corporation

Claims (1)

[Claims] (1) A wiring board that is equipped with a circuit that drives the display panel for a matrix-type display panel that has signal electrodes and scanning electrodes that are orthogonal to each other, and output terminals of the drive circuit are provided on the edges on three sides. At least one of the edges of the wiring board is bent in a direction approaching the display panel, and the terminal electrode of one electrode of the display panel and the bent edge of the wiring board are made to face each other through an anisotropic conductive member. The terminal electrode of the other electrode of the display panel and the edge of the other side of the wiring board are electrically connected via a bent anisotropic conductive member. Terminal connection method for matrix type display device.