JP3004317B2 - Liquid crystal display - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid crystal display device, and more particularly, to COG
The present invention relates to a (Chip On Glass) type liquid crystal display device.

[Prior Art] FIG. 8 is a plan view of a typical conventional liquid crystal display device 1. In the following description, the liquid crystal display device 1 will be described as a simple matrix type. The liquid crystal display device 1 includes a pair of glass substrates 2 and 3, and the surfaces facing each other include:
The first display electrode 4 and the second display electrode 5 are formed. These first display electrode 4 and second display electrode 5 are
It extends out of the display area 8 defined by 3 and serves as a lead terminal 9. The lead terminal 9 is connected to the drive circuit 6 by a bonding wire.

Such a conventional example is the COG method in which a driving circuit 6 formed as a chip on a glass substrate 2 is mounted. The COG method includes a face-down method in which bumps or the like are formed on the drive circuit 6 formed into a chip, and the bumps are exposed to the lead terminals 9 and connected. As another conventional example in which the drive circuit 6 is mounted on the glass substrate 2, a TAB (Tape Automated
Bonding) method. In this method, a drive circuit 6 is attached to a synthetic resin film on which circuit wiring is formed, and the film is connected to the lead terminal 9.

[Problem to be Solved by the Invention] The above-described conventional example has the following problems. In the method of performing wire bonding, it is necessary to connect a bonding wire to the drive circuit 6 for each of the lead-out terminals 9, which takes a long time. Further, in the face-down system, a defective state often occurs with respect to the electrical continuity of a connection portion between the drive circuit 6 formed into a chip and the lead terminal 9. Further, processing such as forming bumps on the chip-shaped drive circuit 6 is required, which complicates the manufacturing process and increases the cost. In the TAB method, a complicated process of mounting the drive circuit 6 on the film and attaching the film to a predetermined portion of the glass substrate 2 is required.

As another conventional example for solving such a problem, there has been proposed a technique of directly forming a drive circuit 6 as an integrated circuit element on a glass substrate 2 using a semiconductor integrated circuit technique. However, with such a technique, the number of drive circuits 6 increases with the enlargement of the display area 8 of the liquid crystal display device 1 and hence with the increase in the number of display electrodes 4 and 5, so that the manufactured liquid crystal display device 1
In many cases, a defective drive circuit 6 is mounted on a semiconductor device, which causes a problem that the production yield is deteriorated.

For this reason, a technique has been proposed in which a large number of the drive circuits 6 are formed on a silicon wafer by using a semiconductor circuit technique, then cut into individual drive circuits 6 and inspected, and only non-defective products are mounted on the glass substrate 2. The drive circuit 6 thus mounted on the glass substrate 2 is connected to the lead terminal 9 using a bonding wire. Therefore, such a technique also causes the above-described problem.

An object of the present invention is to provide a liquid crystal display device that solves the above-mentioned technical problems and improves the production yield and reliability.

Means for Solving the Problems According to the present invention, there is provided a lead-out electrode formed at an end of a main surface of at least one light-transmitting substrate of a display device main body in which a liquid crystal layer is interposed between two light-transmitting substrates. On the other hand, the input / output terminals provided on the non-flexible wiring board on which the semiconductor integrated circuit is mounted are connected via an anisotropic conductive member obtained by mixing fine metal particles in a synthetic resin material having electrical insulation. A liquid crystal display device characterized by being electrically connected to each other by an adhesive and reinforced by bonding an adhesive to both sides of the anisotropic conductive member.

[Operation] A liquid crystal display device according to the present invention includes a display device main body and a non-flexible wiring board. In the display device main body, a liquid crystal layer is interposed between two translucent substrates, and a lead-out electrode is formed at an end of at least one of the translucent substrates on the main surface. On the wiring board,
A semiconductor integrated circuit for driving and driving a display device main body and input / output terminals of the semiconductor integrated circuit are formed. The lead-out electrodes of the display device main body and the input / output terminals of the wiring board are electrically connected by an anisotropic conductive member made by mixing fine metal particles in a synthetic resin material having electrical insulation. An adhesive is fixed to both sides of the conductive member to reinforce the conductive member.

Therefore, when manufacturing a liquid crystal display device, the display device body and the wiring board are separately manufactured, and when combining non-defective products, the lead-out electrodes of the display device body and the input / output terminals of the wiring board are By connecting using the anisotropic conductive member having the above-described configuration, a liquid crystal display device suitable for high-density wiring and high-resolution display, which has recently increased in demand, can be configured. The wiring board can be fixed at a high speed, the production yield can be significantly improved, the production cost can be reduced, and high reliability can be achieved. Further, since the semiconductor integrated circuit is formed on the wiring board together with its input / output terminals, the reliability of the semiconductor integrated circuit with respect to electrical conduction with the wiring board is remarkably improved. When the light-transmitting substrate and the wiring substrate are formed as glass substrates of the same material, the light-transmitting substrate and the wiring substrate have the same thermal expansion coefficient. Therefore, when heat is generated during use or when used in a relatively high-temperature environment, stress generated when both have different coefficients of thermal expansion is eliminated. Also in this respect, the reliability can be improved. Thus, a high-quality liquid crystal display device can be provided at low cost.

Embodiment FIG. 1 is an exploded perspective view of a part of a liquid crystal display device 11 according to an embodiment of the present invention. The liquid crystal display device 11 has a display device main body 14 including a pair of glass substrates 12 and 13 as a translucent substrate.
And a driving circuit 15 for driving and driving the display device main body 14 includes a glass substrate 16 as an inflexible wiring substrate formed as a semiconductor integrated circuit element.

FIG. 2 is a plan view of the liquid crystal display device 11, and FIGS. 3 and 4 are cross-sectional views taken along section lines III-III and IV-IV of FIG. A strip-shaped display electrode 17 extending in the vertical direction in FIG. 2 is formed on the glass substrate 12 from a transparent conductor such as ITO (indium tin oxide). Display electrodes 18 and 19 extending in the left-right direction in FIG. 2 are also formed of ITO or the like on the glass substrate 13. These display electrodes 17, 18, 1
The display area 20 is defined by 9. On the display electrode 17 and the display electrodes 18 and 19, alignment films 21 and 22 are formed. A liquid crystal layer 23 is interposed between them, and the periphery of the display area 20 is sealed with a sealant 24. The display electrodes 17 to 19 are in a display area 20
, And lead-out terminals 25, 26, 27 as lead-out electrodes.

The above-described drive circuit 15 is formed on the glass substrate 16, and the input / output terminals 28 of the drive circuit 15 are pattern-formed from a metal material such as aluminum. The drawer terminal
The input / output terminals 26 and 27 are electrically connected to each other using an anisotropic conductor 29 as an anisotropic conductive member, and the periphery thereof is fixed with an adhesive 30.

FIG. 5 is a diagram for explaining the connection state between the lead terminal 26 and the input / output terminal 28 using the anisotropic conductor 29. The anisotropic conductor 29 of the present embodiment has, for example, a configuration in which fine metal particles 32 are uniformly mixed in a synthetic resin material 31 having electrical insulation. When such an anisotropic conductor 29 is applied between the glass substrates 13 and 16 and pressurized, a stronger pressure is applied between the extraction terminal 26 and the input / output terminal 28 than at a portion where these are not formed. Metal particles added to the isotropic conductor 29
32 contact each other. As a result, electrical continuity is realized between the lead-out terminal 26 and the input / output terminal 28 which face each other in the vertical direction in FIG.

Further, in a range other than the range sandwiched between the extraction terminal 26 and the input / output terminal 28, the pressure on the anisotropic conductor 29 is relatively weak, and the mixed metal particles 32 are separated from each other, The anisotropic conductor 29 has electrical insulation in any direction. Therefore, undesired electrical continuity between the lead terminals 26, between the input / output terminals 28, and between the lead terminals 26 and the input / output terminals 28 which are not vertically opposed in FIG. It is.

Referring again to FIG. 3 and FIG. 4, the lead terminal 25 is connected to the circuit wiring 33 formed on the glass substrate 13 by the anisotropic conductor 29 again. The circuit wiring 33 is connected to an input / output terminal on the glass substrate 16 in the same manner as the lead terminal 27 shown in FIG.
It is connected to 28 via an anisotropic conductor 29. A signal line 34 for inputting a signal indicating a display state of the display device body 14 to the drive circuit 15 is formed on the glass substrate 16, and the signal line 34 is a signal line 35 formed on the glass substrate 13.
Is connected to the signal line 35 through the anisotropic conductor 29.
Is connected to the circuit wiring 37 of the flexible wiring board.

The drive circuit 15 and the input / output terminals 28 are formed on the glass substrate 16 in the following manner. First, the glass substrate
A thin film of polycrystalline silicon is formed on 16, and a drive circuit 15 and an input / output terminal 28 are formed thereon by semiconductor integrated circuit technology.

In the liquid crystal display device 11 of this embodiment, since the drive circuit 15 and the input / output terminal 28 are directly formed on the glass substrate 16 by the semiconductor integrated circuit technology, the drive circuit 15 is separately manufactured as an integrated circuit element. As compared with the case where the semiconductor device is fixed on the glass substrate 16, the reliability regarding the electrical continuity between the drive circuit 15 and the input / output terminal 28 is significantly improved.

In manufacturing the liquid crystal display device 11, a driving circuit
The liquid crystal display device 11 may be manufactured by separately manufacturing the glass substrate 16 on which the substrate 15 is formed and the display device main body 14, and combining non-defective products. Therefore, the production yield can be significantly improved. In addition, since the glass substrates 12, 13, and 16 are made of the same material, the glass substrates can be used even when the heat is generated during use and the device is placed in a relatively high temperature environment.
The occurrence of stress based on the difference between the thermal expansion coefficients of the materials 12 and 13 and the glass substrate 16 that are assumed when they are made of different materials is prevented. This improves reliability.

Further, since the display device main body 14 and the glass substrate 16 are electrically coupled by the anisotropic conductor 29, the manufacturing process is simplified.

FIG. 6 is a sectional view of a liquid crystal display device 11a according to another embodiment of the present invention. This embodiment is similar to the previous embodiment, and corresponding parts are denoted by the same reference numerals. In each of the above embodiments,
The drive circuit 15 on the glass substrate 16 is formed by forming a polycrystalline silicon thin film on the glass substrate 16 and using a semiconductor integrated circuit technology thereon. On the other hand, in the present embodiment, the driving circuit 15
Are formed separately using a semiconductor integrated circuit technology, in the state of a so-called bare chip in a state where the connection bumps 41 used for input / output of signals and the like are formed and not covered with a synthetic resin material or the like, Fixed on 16 The drive circuit 15 and the input / output terminal 28 on the glass substrate 16 are connected to each other by a bonding wire 40 such as gold. The glass substrate 16 at such a stage is connected to the display device main body 14 in the same manner as in the above-described embodiment.

The liquid crystal display device 11a having such a configuration and manufacturing method can also achieve the same effects as those described in the above embodiments.

FIG. 7 shows a liquid crystal display device 11 according to still another embodiment of the present invention.
It is sectional drawing of b. This embodiment is similar to the previous embodiment,
Corresponding parts have the same reference characters. The point of interest in this embodiment is that the integrated circuit 15 mounted on the glass substrate 16
Is used as the bare-chip integrated circuit 15 having the bumps 41 in the embodiment described with reference to FIG.
The integrated circuit 15 is connected to the glass substrate 16 by a face-down bonding method in which the bumps 41 are directly connected to the input / output terminals 28 on the glass substrate 16 by soldering or the like. Even in such an embodiment, the same effect as the effect described in the above embodiment can be achieved.

[Effects of the Invention] As described above, according to the present invention, when manufacturing a liquid crystal display device, a display device main body and a wiring board are separately manufactured, and a non-defective product is selected from these to derive the display device main body. The electrodes and the input / output terminals of the wiring board are electrically connected by an anisotropic conductive member obtained by mixing fine metal particles in a synthetic resin material having electrical insulation. Reinforce both sides with adhesive. As a result, the non-flexible wiring board can be firmly and easily fixed to the display device main body with a small number of steps. As a result, the production yield is increased, the production cost is reduced, A high-quality liquid crystal display device suitable for display of resolution can be provided at low cost.

When the light-transmitting substrate and the wiring substrate are configured as a glass substrate of the same material, heat is generated during use, or when used in a relatively high-temperature environment, the light-transmitting substrate and The stress that occurs when the thermal expansion coefficients of the wiring board and the wiring board are equal and therefore the thermal expansion coefficients of the two boards are different is eliminated. Also in this respect, the reliability can be improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a part of a liquid crystal display device 11 according to one embodiment of the present invention, FIG. 2 is a plan view of the liquid crystal display device 11, and FIGS. 5 is a cross-sectional view illustrating the operation of the anisotropic conductor 29, and FIG. 6 is a cross-sectional view illustrating the liquid crystal display device 11 according to another embodiment of the present invention.
FIG. 7 is a cross-sectional view of FIG. 7A, FIG. 7 is a cross-sectional view of a liquid crystal display device 11b of still another embodiment of the present invention, and FIG. 8 is a plan view of a typical conventional liquid crystal display device 1. 11, 11a, 11b: Liquid crystal display device, 12, 13, 16: Glass substrate, 14: Display device body, 15: Drive circuit, 17 to 19:
Display electrode, 25 to 27 ... Lead-out terminal, 28 ... Input / output terminal,
29 ... anisotropic conductor, 40 ... bonding wire, 41 ...
... Bambu

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/1345 G09F 9/00 H05K 3/32

Claims (1)

(57) [Claims] 1. A semiconductor integrated circuit is connected to a lead-out electrode formed at an end of a main surface of at least one light-transmitting substrate of a display device body having a liquid crystal layer interposed between two light-transmitting substrates. The input / output terminals provided on the mounted inflexible wiring board are electrically connected via an anisotropic conductive member formed by mixing fine metal particles with a synthetic resin material having electrical insulation, and A liquid crystal display device wherein an adhesive is fixed to both sides of the anisotropic conductive member and reinforced.