JPS5922088A - Liquid crystal 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 liquid crystal display device. Specifically, the present invention relates to a liquid crystal display device W in which a driving circuit is mounted on a liquid crystal panel and is integrated with a substrate.

Conventionally, conductive rubber has generally been used to connect a liquid crystal panel and a circuit board. However, because conductive rubber moves easily, it is difficult to align the conductive rubber for electrical connection.
The conductive rubber had to be held down with a constant force, which made it difficult to adjust the force, the pressure tended to be uneven, and the circuit board was prone to bending due to the force that crushed the conductive rubber, resulting in a loss of reliability.

An object of the present invention is to eliminate such drawbacks and provide a highly reliable liquid crystal display device f6.

The liquid crystal display device of the present invention uses a flexible substrate to connect the liquid crystal panel and the circuit board, and the flexible substrate is connected to the liquid crystal panel and the circuit board by soldering.
This object is achieved by disposing an elastic body between the liquid crystal panel and the circuit board, and by pressing the joint between the flexible substrate and the liquid crystal panel or the circuit board.

Hereinafter, the liquid crystal display device of the present invention will be explained using the drawings.

FIG. 1 is a schematic diagram of a first embodiment of the liquid crystal display device of the present invention. The liquid crystal panel 1 is attached to the circuit board 3 by the holding frame 2.
is fixed to the terminal on the circuit board 3, and the power supply and other simple signals are input from the outside and displayed on the liquid crystal panel 1 (
For example, "F, psoNJ) E is being performed.

FIG. 2 shows a cross-sectional view of the liquid crystal display device f'tffi of the present invention, which is the first embodiment of the present invention shown in FIG.
The figure shows an exploded view.

The liquid crystal panel 1 shown in FIGS. 2 and 3 consists of at least two glass substrates and a liquid crystal material sandwiched between them. The liquid crystal panel 1 is a twisted nematic type (
Hereinafter, it will be abbreviated as TN type. ), the upper and lower 04 light plates and reflection plates are fixed to the substrate with a silicone-based or acrylic-based adhesive or adhesive. When the liquid crystal panel 1 is a White-Taylor guest-host type (hereinafter abbreviated as GH type), a UV"74 filter is attached to the upper surface of the liquid crystal panel 1, and a reflection plate is attached to the lower surface.

On the circuit board 3, at least a driving element 4 such as an IC for driving and displaying the liquid crystal panel 1 is mounted. As the substrate 3, a Gala Evo board, one paper Evo board, one paper phenol board, or a 004 board (manufactured by Hitachi Chemical) is used. Gala Evo board has high hardness and low heat shrinkage.
It has good environmental resistance and is highly reliable. Paper evo substrates, paper phenol substrates, or 004 substrates are inexpensive.

In particular, the manufacturing process of the 004 substrate is simple and the cost is low. The circuit board 3 needs to have a certain degree of hardness, and extremely soft materials such as flexible boards are generally not suitable. However, since the liquid crystal panel 1 and the circuit board 3 are connected by soldering to the flexible board 5, the thickness of the circuit board 3 is much softer than when conventional conductive rubber is used. A metal pattern on the circuit board 6 is exposed at a connection point between the circuit board 3 and the flexible board 5 (hereinafter referred to as a board connector section). The metal pattern is generally a copper foil and preferably has a thickness of 3 to 20 μm or less. Ordinary copper foil has a thickness of 39/I m, but the thickness of the copper foil of the board connector portion 31 of the circuit board 3 used in the liquid crystal display device of the present invention is within the range of 3 to 20/I m. Use something thin. On the silver foil pattern, nickel plating, no-1 da plating, gold plating, gold flash, power! 1 A thin metal layer of 0.1 to 5/J tn may be formed by electrolytic gold plating, silver plating, silver flash, or electroless silver plating. The thickness of the metal pattern of the board connector part 31 is as follows: When a layer is formed, the thickness including the irj metal layer shall be within the range of 3 to 20 μm. By forming a thin metal layer on a metal pattern such as copper foil, the film-like electrode connector 5
The reliability of the electrical connection between the circuit board 3 and the circuit board 3 is improved by 1 μm due to the rust prevention of the metal pattern. There are advantages such as improved drive display characteristics because there is no sag in the drive waveform. q "3 This advantage is especially great when thin metal is formed on the foil.Gold plating by electrolysis is used especially in fields where reliability is required, and when the terminal for electrolytic plating cannot be removed. It is preferable to perform electroless gold plating or gold flash.The circuit board 3 is provided with an external terminal 32 for electrical connection to the outside at !111.A connector may be connected to this terminal.

Attachment holes 30 are provided at the four ends of the circuit board 3 so that the present liquid crystal display device can be easily attached to an external device.

A through hole 20 is also provided in the presser frame.

The liquid crystal display device of the present invention includes bolts, nuts, screws, etc.
It is used by attaching to an external device through the receptacle hole 20.30.

The flexible substrate 5 electrically connects the rotating substrate 3 and the liquid crystal panel 1. The flexible substrate 5 used includes, for example, a 35 micron silver foil formed on a 25 μm washable polyimide base film. At least the copper foil is exposed at the terminal portions of the flexible substrate 5 that are connected to the liquid crystal panel 1 and the circuit board 3. The flexible substrate 5 is connected to the liquid crystal panel 1 or the circuit board 3 by forming a solder layer on at least one of the terminals and soldering them together, by applying heat, or by applying heat and ultrasonic waves at the same time. It will be done. For example, solder is applied to the terminals of the flexible substrate 5 and the terminals of the liquid crystal panel 1 and the circuit board 3 using a soldering iron to form a solder layer.

Next, the terminal positions of the flexible substrate 5 and the liquid crystal panel 1 or the circuit board 3 are aligned, and the two are screwed together and a temperature of about 120 to 500° C., which is the temperature at which the solder layer melts, is applied to completely join them. In addition, if 7lux is mixed in the solder, if you clean it with polyhydric alcohol after forming a solder layer on the terminal or after applying solder (=J) to both, the joint will be damaged by the residual flux. 1. The appearance does not become unsightly.Also, another method is to bond the flexible substrate 5 and the liquid crystal panel 1 on at least one terminal, and to bond the flexible substrate 5 and the liquid crystal panel 1 on at least one terminal. After brushing solder cream onto one terminal, using screen printing, etc., and aligning and overlapping the positions of both terminals to be joined, apply approximately 1.
Both may be soldered by applying heat of 20 to 300°C. At this time, if ultrasonic waves are used in combination, the bond will be stronger and the production time will be shorter. Furthermore, among the flexible substrate 5° liquid crystal panel 11 circuit board 3, two parts to be joined are overlapped with their terminal positions aligned, and the solder is melted on the overlapped terminal part using a heating means such as a soldering iron. You can also pour it in and solder the two together.

The elastic body 6 is made of sponge rubber, natural rubber, urethane foam,
It is an elastic body made of foamed polyurethane, silicone rubber, etc., and is formed in a size such that it is compressed when the liquid crystal panel 1 is fixed to the circuit board 3 by the holding frame 2, and uses the repulsive force generated thereby. , flexible substrate 5
This is to hold down the connection parts of the liquid crystal panel 1 and the circuit board 3. In addition to this, the elastic body 6 also has the function of a support body that holds the liquid crystal panel 1 in a predetermined position. The flexible substrate 5 is bonded to the liquid crystal panel 1 and the circuit board 3 by soldering, but since the elastic body 6 further presses this bonded portion, the bonded portion may peel off and the mechanical connection may be broken. In addition, the elastic body 6 prevents short circuits and leaks from occurring at the joint due to dust, etc.
1 improves emotional reliability.

The coupling member 61 may be formed on one or both surfaces of the elastic body 6. The bonding portion i: A11 may be a commercially available double-sided tape. Further, in this case, an acrylic adhesive, a rubber adhesive, or a thermoplastic adhesive is formed on the surface of the elastic body 6 by spraying, brushing, screen printing, or the like. For example, Cemedine KK's "a 40
There is oJ.

The presser frame 2 is a thin metal plate with a thickness of 01 to 1.2 m.
It is mJ quantity. The materials used are iron, copper, copper, and brass.

There are stainless steel and aluminum plates. The thin metal plate used for the presser frame 2 has a constant thickness, and is made of rolled metal material.
For example, rolled steel plate is good. Iron materials are the cheapest available. When iron powder is used, plating with nickel, chromium, etc. will provide a rust-preventing effect. Furthermore, the use of stainless steel plates has advantages such as being resistant to rust, easy to process, and strong. The presser frame 2 is as shown below.
A single metal plate is pressed into a predetermined shape and then bent.

Next, a method for assembling the liquid crystal display device of the present invention using such parts will be explained. First, on LCD panel 1,
The flexible substrate 5 is connected by soldering. Next, the other terminal of the flexible board 5 is connected to the circuit board 3 by hot pressing. Next, the elastic body 6 is installed under the terminal of the liquid crystal panel 1. Next, attach the presser frame 2 to the LCD panel 1.
The legs 23 are set into the holes 35 of the circuit board 3 from above. Next, the legs 23 of the holding frame 2 protruding from the back side of the hole 33 of the circuit board are twisted to fix the holding frame 2 and the liquid crystal panel 1 to the circuit board 3.

In addition, when assembling, if holes 20 and 30 for assembly are provided in the presser frame 2 and the circuit board 3, the workability will be improved.
In addition, the alignment of the liquid crystal panel 1 is completed, and a liquid crystal display device with good appearance is assembled. When fixing the presser frame 2 to the circuit board 3, pass long and thin pins (hereinafter referred to as pins) through the assembly holes 20 of the presser frame 2 and the assembly holes 30 of the circuit board 3, and then use the upper HC bin to connect the circuit board. Align the substrate 5 and the presser frame 2 so that the holes 20.30 and the pins are positioned so that the outer periphery of the liquid crystal panel 1 is exactly in contact with the outer periphery of the hole 20.30 and the pin. Next, the liquid crystal panel 1 is moved so that its outer periphery touches the outer periphery of the pins inserted into the holes 20 and 30. Next, the legs 23 of the presser frame 2 are moved.
Twist and attach the LCD panel 1 and frame 2 to the circuit board 3.
to be fixed.

FIG. 4 shows a first embodiment of the flexible substrate 5 used in the liquid crystal display device +b of the present invention. Figure 4 (rL)
is a plan view, and (b) is a sectional view. 51 is a polyimide-based or polyester-based base film, and has a thickness of 20 to 100 II m.

Polyimide has excellent heat resistance and is easy to solder.
Polyester-based materials have poor heat resistance and require careful soldering, but are inexpensive. 52 is a metal foil such as copper foil, aluminum foil, or iron foil formed on the base film, and the thickness is 20~20 mm.
It is 50 μm. Examples of copper foil include electrolytic copper foil and rolled copper foil. Electrolytic copper foil allows fine patterns to be formed, while rolled silver foil has excellent bending resistance, is advantageous in cases of tight bending, and is inexpensive. By using such a flexible substrate 5, it becomes possible to solder the connecting portions.

FIG. 5 shows a second embodiment of the flexible substrate 5. As shown in FIG.

FIG. 5(a) is a plan view, and FIG. 5(h) is a sectional view. 51.
Reference numerals 52 denote a base film and metal foil, respectively, which are similar to those explained in FIG. 4. An overlay 53 is provided on the metal foil 52. The sub-burley 53 is made of solder resist ink or film. ) 1y salmon number 71 fi ~ 60 /J? It is about 7L. The film used is polyimide or polyester. The properties of this film are similar to those described in FIG. By forming the overlay 53, the flexibility of the flexible board 5 is strengthened, and by covering the parts other than the terminals, short-circuits with other parts or dust can be prevented.
J-fitting eliminates short circuits and leaks.

FIG. 6 shows a sixth embodiment of the flexible substrate 5.

A reinforcing member 54 made of a reinforcing plate or a reinforcing film is provided below the base film 51. Reinforcement part It 54
When using a reinforcing plate as a reinforcing plate, a paper phenol substrate or a glass epoxy substrate with a thickness of 0.2 to 1-6 mm is used. When using a reinforcing film as the reinforcing part 1454, T3 of 005 cylinder to t o mm IV? Reester film is used. These are used when strength is required.

In addition, the base film "1 gold H5 pattern 52t
Metal honeycomb 52.!=n-barley film 53,
The base film 51 and the reinforcing member 54 are bonded together using an adhesive or adhesive.

FIG. 7 is a sectional view of a second embodiment of the liquid crystal display device d of the present invention. Transparent electrodes are formed on the terminal portions of the liquid crystal panel 1, and an electroless nickel plating layer is formed thereon. And the nickel plating Jt
Molten solder is applied to the top with a soldering iron.
A thin Noonda layer is formed. The circuit board 3 is a glass epoxy board, and the terminal portion has a gold layer made of gold flash formed on a copper foil pattern. Then, molten solder is applied onto the gold layer using a soldering iron to form a thin solder layer. The flexible substrate 5 has a copper foil pattern formed on a polyimide resin base, and molten solder is applied onto the silver foil pattern using a soldering iron to form a thin solder layer. The terminal portions of the flexible substrate 5, the liquid crystal panel 1, and the circuit board 3 were aligned, and the terminal portions were heated and compressed using ultrasonic waves, and both were soldered. The elastic body 6 was made of foamed neoprene. Elastic body 6 top 0 circuit board 3
On the side is double-sided adhesive tape T made by Sony Chemical KK.
I pasted the 4000F and got it. Next, an elastic body 6 is attached to the terminal portion to which the flexible board 5 on the circuit board s is soldered.
was attached using double-sided adhesive tape. And j:
1. :The liquid crystal panel 1 is fixed onto the circuit board 3 by a pressing frame 2 formed by pressing an XOξ steel plate.

In this way, the terminal part of the circuit board 3 connected to the flexible board 5 can be connected to the joint part 4' made of double-sided adhesive tape.
Since the elastic body 6 made of nemeprene can be reliably pressed through A' 61, the elastic body 6 will not move, and the liquid crystal panel will be stable against vibrations and cracks. Assembly was easy because the position of 6 was fixed.

FIG. 8 is a sectional view of a third embodiment of the liquid crystal display device d of the present invention. The fifth embodiment of the liquid crystal display device of the present invention shown in FIG. 8 is assembled with the same H quality of each component as the second embodiment of the liquid crystal display device of the present invention shown in FIG. It is something that The difference is that the elastic body 6 is made of foamed neoprene.
The circuit board 3111Q and the liquid crystal panel 1flllI
A connecting member 6 made of double-sided adhesive tape on both sides 1f11 of
1 is pasted together.

In this way, the circuit board 5, elastic body 6, and liquid crystal panel 1 are mutually coupled via the coupling member 61 made of double-sided tape, so that the alignment of the liquid crystal panel 1 with respect to the circuit board 3 is perfect! It is I.

Configuring the liquid crystal display device of the present invention in this manner has the following advantages.

(1) The liquid crystal panel 1 and the circuit board 5 are flexible substrates 5
The connection pattern on the flexible substrate 5 is formed of gold foil such as copper foil, and compared to the connection pattern of conductive rubber, which is formed of graphite particles, for example, the connection pattern on the flexible substrate 5 is a continuous Because it is a metal pattern,
The reliability of the connecting circuit is high, and the electrical resistance of the connecting circuit is low.

(2) The connection terminals of the flexible substrate 5 and the liquid crystal panel 1 and the flexible substrate 5 and the circuit board 3 are connected by solder (q), and the electrical resistance of the connection is low and the mechanical strength is high. In the case of rubber, the conductive rubber must be crushed with a certain force, and the electrical resistance of the connection part was large, several ohms, but in the case of soldering, it is less than a few ohms.Therefore, the output end of the driver It is possible to reduce the electrical resistance from the LCD to the liquid crystal, and to reduce the time constant, making it possible to maximize the response speed of the liquid crystal without sacrificing the liquid crystal drive waveform. Therefore, it is effective for automobiles and dual-frequency applications where high response speed is required.In addition, there is no difficulty in keeping the rubber at a constant position as in the case of the conductor R1 rubber.

(8) The connection terminal portions of the flexible substrate 5 and the liquid crystal panel 1 and the flexible substrate 5 and the circuit board 3 are connected by soldering, and although this connection portion is hard, it is held down by a soft elastic body 6. This prevents the hard soldered connections from breaking. In addition, when a shock force or vibration is applied to the liquid crystal display of the present invention, the impact force or vibration is absorbed by the elastic body 6, so that the liquid crystal panel 1, the circuit board 5, or the joint part is not damaged. There is no. Furthermore, since the connecting portion is covered with the elastic body 6, it is possible to prevent leaks and short circuits caused by dust, dirt, etc. on the chair.

(4) Since the liquid crystal panel 1 and the circuit board 3 are connected by soldering on the flexible board 5, the electrical connection between the liquid crystal panel 1 and the circuit board 3 is easy and reliable. Conductive rubber is used. and LCD, < panel 1 and circuit board 3
However, in the liquid crystal display device of the present invention, the flexible substrate 5 is connected to the liquid crystal panel 1 and the circuit board 3 by soldering, so that the workability is easy. It is reliable, there is no misalignment of terminal alignment or conductive rubber connections, and it is reliable and has good workability.

(5) In the liquid crystal display device a of the present invention, the force that would crush the conductive rubber is not applied when pressing the elastic body 6 to establish electrical continuity, so the circuit board 3 may be soft. The material r1 can be selected from a wide variety of inexpensive materials.

As described above, the liquid crystal display device N of the present invention is easy to assemble, has high reliability, and greatly contributes to the development of industry.

[Brief explanation of the drawing]

FIG. 1 is an overview diagram of a first embodiment of the liquid crystal display device of the present invention, FIG. 2 is a sectional view, and diagram tR3 is an exploded elevational view. FIG. 4 shows a first embodiment of the flexible substrate. FIG. 5 shows a second embodiment of the flexible substrate. FIG. 6 shows a third embodiment of the flexible substrate. FIG. 7 shows a second embodiment of the liquid crystal display device of the present invention. FIG. 8 shows a third embodiment of the liquid crystal display device of the present invention. 1...Liquid crystal panel 2...Press frame 3...Circuit board 5...Flexible board 6...Elastic body or more Applicant: Shinshu Seiki Co., Ltd. Representative Patent Attorney Mr. Mogami Figure 1 Figure 2 1 Figure 3

Claims (1)

[Claims] (1) A liquid crystal display device comprising at least a liquid crystal panel, a circuit board on which a driving element for driving the liquid crystal panel is mounted, and a holding frame for fixing the liquid crystal panel to the circuit board, The liquid crystal panel and the circuit board are 1L using flexible boards. The flexible substrate is coupled to the liquid crystal panel and the circuit board by soldering, and the flexible substrate and the liquid crystal panel or the flexible substrate are connected between the liquid crystal panel and the circuit board. A liquid crystal display device (d
0