JPH09152619A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the low-cost liquid crystal display device of high quality which is reduced in manufacture cost and improved in the reliability of bonding to a driving IC. SOLUTION: The liquid crystal display device 14 is constituted by arranging a glass substrate 3 between a couple of glass substrates 2 and 3 having a display area 4 and a wiring substrate 5b so that their end surfaces face each other. Further, the glass substrate 3 and wiring substrate 5b are arranged on a metallic plate 6a, the glass substrate 2 and wiring substrate 5b are arranged on a metallic plate 6b, and the wiring substrate 5b is provided with a pad array surface 16 where plural bonding pads 15 are arrayed. Further, the driving IC 8b has its terminal 20 fixed on a nondisplay area 9a of the glass substrate 3 by face- down bonding and a terminal 21 of the driving IC 8b is arranged outside the glass substrate 3 and bonded to a bonding pad 14 individually.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art A conventional liquid crystal display device 1 is shown in FIGS. 5 to 7, and FIG. 5 is a plan view thereof, and FIGS. 6 and 7 are an enlarged plan view and an enlarged sectional view of a region A shown in FIG. It is.

In the liquid crystal display device 1, liquid crystal (not shown) is sealed between the upper glass substrate 2 and the lower glass substrate 3, and display electrodes (not shown) are orthogonal to each other on the inner surface of each. The lower glass substrate 3 and the wiring substrate 5 such as a printed circuit board are arranged side by side on the lower glass substrate 3 so as to face each other, and the display substrate 4 is arranged on the metal plate 6 made of stainless steel or the like. The lower glass substrate 3 and the wiring substrate 5 are fixed by an adhesive resin 7. In addition, the drive IC8
Are arranged on the wiring board 5 and the lower glass substrate 3, and the display electrodes of the display area 4 are connected to the output side wirings 10 provided in the non-display area 9 of the lower glass substrate 3, and further on the wiring board 5. Bonding pad 11 is also formed. And
Each terminal of the drive IC 8 has an output side wiring 10 (a part of which constitutes a bonding pad) and a bonding pad 11.
Is connected by wire bonding 12 and the drive IC 8 is covered with resin (not shown) for protection. Reference numeral 13 denotes a coordinate recognition marker for mounting an IC or bonding a wire to an IC terminal.

[0004]

However, in the liquid crystal display device 1 having the above structure, since the two types of terminals of the drive IC 8 are both connected by the wire bonding 12, it takes a long time. In particular, when the number of wire bondings 12 increases with the increase in density and color, there is a problem that the required time becomes considerably long. Moreover, even if the driving IC 8 is coated with resin, if pressure is applied from the outside, cutting of the wire bonding 12 is not completely avoided.

In order to solve the above problems, the drive IC 8
There is a technique for face down bonding of the drive IC 8 in such a case that the drive IC 8 is arranged so as to straddle the non-display area 9 of the lower glass substrate 3 and the wiring substrate 5.
One of the types of terminals is bonded to the non-display area 9 and the other is bonded to the wiring board 5.

However, with such a face-down bonding method, the bonding itself becomes unstable due to the difference in coefficient of thermal expansion due to the difference in material between the lower glass substrate 3 and the wiring substrate 5, and even after bonding. There is a problem that it comes off.

Therefore, it is an object of the present invention to shorten the time required for bonding to a drive IC and shorten the manufacturing time, thereby reducing the manufacturing cost and further improving the reliability of the bonding, resulting in high An object of the present invention is to provide a liquid crystal display device which is of high quality and low cost, and which is further miniaturized.

[0008]

In a liquid crystal display device of the present invention, one glass substrate of a pair of glass substrates having a display area bonded via liquid crystal, and a wiring substrate are provided with their end faces being opposite to each other. Are arranged side by side so that one metal plate is provided on one main surface of one glass substrate and wiring board and the other metal plate is provided on the other main surface of the other glass substrate and wiring board. A drive IC in which a plurality of bonding pads are arranged in parallel with each other and a plurality of bonding pads are arranged in parallel with each other are provided in a portion of the substrate facing the other metal plate. Is fixed by face-down bonding on the non-display area of one glass substrate, and the drive I
The other terminal row of C is arranged outside one glass substrate,
It is characterized in that wire bonding is individually performed to the bonding pads on the pad arrangement surface of the wiring board.

Another liquid crystal display device of the present invention is the liquid crystal display device of the above invention, in which a bent metal plate having a U-shaped cross section is fitted to the wiring board, and the pair of bent metal plates face each other. Of the metal plates are one metal plate and the other metal plate, respectively.

[0010]

DETAILED DESCRIPTION OF THE INVENTION A liquid crystal display device 14 of the present invention is shown in FIG.
4A and 4B, FIG. 1 is a plan view of the liquid crystal display device 14, FIG. 2 is an enlarged plan view of a region B shown in FIG. 1, and FIG. 3 is a cross-sectional view of a main part taken along a section line XX in FIG. FIG. 4 is a right side view of the main part as seen from the arrow Y direction in FIG. FIG. 8 shows another liquid crystal display device 14a of the present invention. However,
FIG. 2 is a view seen from the back side of FIG. 1, and one metal plate arranged on the one glass substrate and the wiring substrate is omitted. Note that the same members as those of the conventional liquid crystal display device 1 are denoted by the same reference numerals.

In the liquid crystal display device 14, a liquid crystal (not shown) is provided between the upper glass substrate 2 which is the glass substrate on the common side and the lower glass substrate 3 which is the glass substrate on the segment side by a sealant (not shown). , And display electrodes (not shown) made of a transparent conductor such as ITO are arranged on the inner surfaces of the upper and lower glass substrates 2 and 3 so as to be orthogonal to each other, and an alignment film (not shown). ) Is coated on the display electrode to form the display region 4. Further, on the lower glass substrate 3, wiring boards 5a and 5b such as printed boards are arranged in parallel so that the end faces thereof face each other.

Then, the lower glass substrate 3 and the wiring substrates 5a and 5b are fixed on the metal plate 6a made of stainless steel (SUS) or the like as the one metal plate with the black adhesive resin layer 7a interposed, and further. The upper glass substrate 2 and the wiring substrates 5a and 5b are fixed on a metal plate 6b made of stainless steel (SUS) or the like as the other metal plate with a black adhesive resin layer 7b interposed. With such a fixing method, the width when the upper glass substrate 2 and the lower glass substrate 3 are bonded together, and the wiring substrates 5a, 5
The width of b is almost the same. The black adhesive resin layer 7
For a and 7b, tapes (for example, No. 3161-F [black one-sided tape] manufactured by Nitto Denko KK and No. 591) are used.
5 (double-sided tape)) can be attached.

The wiring boards 5a and 5b have, for example, a multilayer wiring structure in which one or more wiring layers can be formed inside the board and / or a structure in which wiring layers are formed on both main surfaces. A bus line group including a power supply and a signal line necessary for driving 8b is wired. Further, if necessary, each system such as a power supply and a logic may be wired for each layer, or various power supplies and signal processing circuits supplied from the outside may be mounted. In this embodiment, the case where six glass epoxy plates are stacked is illustrated.

In the wiring boards 5a and 5b having such a structure, a pad array surface 1 in which a plurality of bonding pads 15 are arrayed at a portion facing the metal plate 6a.
6 and an adhesion surface 17 of the metal plate 6a. Since the wiring boards 5a and 5b have a long shape, the bonding surfaces 17 are provided at both ends in the longitudinal direction, and the pad array surface 16 is provided between the bonding surfaces 17.

Then, the drive IC 8a straddles the non-display area 9 of the lower glass substrate 3 and the wiring board 5a,
8b is arranged over the non-display area 9 of the lower glass substrate 3 and the wiring board 5b. 18 is a drive IC 8a,
8b is a resin adhesive that fixes onto the lower glass substrate 3.
In addition, the pressing portion 19 made of glass epoxy or the like is used for driving the IC 8
It may be placed on a and 8b so that no gap can be formed between the metal plate 6b and the metal plate 6b to enhance the impact from the outside.

Each of the drive ICs 8a and 8b has two types of terminals 2
0 and 21 are arranged in parallel. The display electrodes of the display area 4 are the output side wirings 10 provided in the non-display area 9 of the lower glass substrate 3 (a laminated body in which a Ni layer and an Au layer are sequentially laminated on the ITO layer, or on the ITO layer. Since it is connected to the output side wiring 10, one terminal 20 (for example, made of Au and solder) is face-down bonded to the output side wiring 10, and the other terminal. 21 and the bonding pads 15 provided on the pad array surface 16 of the wiring boards 5a and 5b are individually wire-bonded 22 (φ32 μm or φ
25 μm gold wire).

In the liquid crystal display device 14 having the above structure, the wiring boards 5a and 5b are provided, and the driving IC 8 is further provided.
In order to fix and bond (connect) a and 8b, the following steps are performed. In the liquid crystal display device 14, a structure in which the wiring boards 5a and 5b and the driving ICs 8a and 8b are not provided is called a liquid crystal cell.

(1) For the liquid crystal cell, the driving IC 8 is provided on the non-display area 9 (output side wiring 10) of the lower glass substrate 3.
Face down bonding of a and 8b.

(2) The liquid crystal cell and the wiring boards 5a and 5b are fixed on the metal plate 6b via the black adhesive resin layer 7b.

(3) The other terminal 2 of the drive ICs 8a and 8b
1 and the bonding pad 15 provided on the pad array surface 16 of the wiring boards 5a and 5b are individually wire-bonded 22.

(4) The liquid crystal cell and the wiring boards 5a and 5b are fixed on the metal plate 6a via the black adhesive resin layer 7b.

Thus, in the liquid crystal display device 14, wire bonding 22 is performed to the other terminal 21 of the drive ICs 8a and 8b, but face down bonding is performed to one terminal 20, so that Since the time required for face-down bonding is extremely short, the overall manufacturing time can be shortened.

Further, according to the liquid crystal display device 14, the drive ICs 8a and 8b are arranged over the non-display area 9 of the lower glass substrate 3 and the wiring boards 5a and 5b. Since it is not fixed to 5b, the influence of the difference in the coefficient of thermal expansion due to the difference in material between the lower glass substrate 3 and the wiring substrate 5 is eliminated, and stable bonding can be performed.

Next, referring to FIG. 8 showing another liquid crystal display device 14a of the present invention, a bent metal plate having a U-shaped cross section and having the same function, made of Al or the like, is used instead of the metal plates 6a and 6b. 23 are fitted so as to sandwich the wiring boards 5a and 5b, whereby a pair of plates of the bent metal plate 23 facing each other form metal plates 6a and 6b, respectively.

According to the liquid crystal display device 14a having the above structure,
Furthermore, wire bonding 22 is applied against pressure from the outside.
Will be protected and will not be disconnected.

The present invention is not limited to the above embodiment, and various changes and improvements may be made without departing from the scope of the present invention.

[0027]

As described above, according to the liquid crystal display device of the present invention, a driving IC in which two types of terminals are arranged is face down with one terminal row on the non-display area of one glass substrate. By bonding and fixing, and arranging the other terminal row outside one glass substrate and wire-bonding individually with the bonding pads on the pad arrangement surface of the wiring board, the manufacturing time can be shortened. As a result, the manufacturing cost is reduced, the reliability of bonding to the drive IC is further increased, and as a result, it is possible to provide a miniaturized liquid crystal display device of high quality and low cost.

[Brief description of the drawings]

FIG. 1 is a plan view of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of the liquid crystal display device according to the embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of a main part of the liquid crystal display device according to the embodiment of the present invention.

FIG. 4 is a side view of the liquid crystal display device according to the embodiment of the present invention.

FIG. 5 is a plan view of a conventional liquid crystal display device.

FIG. 6 is an enlarged view of a main part of a conventional liquid crystal display device.

FIG. 7 is an enlarged cross-sectional view of a main part of a conventional liquid crystal display device.

FIG. 8 is an enlarged cross-sectional view of a main part of a liquid crystal display device according to another embodiment of the present invention.

[Description of sign]

 2 Upper glass substrate 3 Lower glass substrate 4 Display area 5, 5a, 5b Wiring board 6, 6a, 6b Metal plate 8, 8a, 8b Driving IC 9 Non-display area 14, 14a Liquid crystal display device 15 Bonding pad 16 Pad arrangement surface 23 Bent metal plate

Claims (2)

[Claims] A first glass substrate having a display region bonded through a liquid crystal;
The wiring board and the two end surfaces are arranged side by side so that one metal plate is on one main surface of the glass substrate and the wiring board, and the other metal board is on the other main surface of the other glass substrate and the wiring board. The other metal plate is provided, and a pad array surface on which a plurality of bonding pads are arrayed is provided on a portion of the wiring board facing the other metal plate, and two types of terminals are arrayed in parallel. The drive IC has one terminal row fixed to the non-display area of one glass substrate by face-down bonding, and the other terminal row of the drive IC is arranged outside the one glass substrate to form a wiring board. Liquid crystal display device with individual wire bonding to the bonding pads on the pad array surface. 2. A bent metal plate having a U-shaped cross section is fitted to the wiring board, and a pair of plates facing each other form one metal plate and the other metal plate, respectively. The liquid crystal display device according to claim 1, wherein: