JPH10312244A - Liquid crystal display device with input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of color irregularity owing to a temperature change and humidity by connecting electric wires to the plainly different positions in respective input boards. SOLUTION: An input device is formed by a pair of input boards 1 and 4 having input electrodes for the confronting faces of the boards. At that time, heat seals are used for the flexible electric wires 7. One flexible electric wire 7 is connected only to the upper board 1 and the second wire is connected only to the lower board 4. If a place where the upper board 1 and the lower board 4 are completely fixed exists when the upper board is contracted owing to the temperature change and humidity, partial tension change occurs in the periphery of the place where the upper board 1 is fixed to the lower board 4 by upper/lower conduction. Then, the adhesive of double coated tape is used for a sealing member 8 assembling the upper board and the lower board 4. Thus, the occurrence of color irregularity owing to the temperature change and humidity can be suppressed without completely fixing the boards by adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display having an input function of inputting with a finger or a pen disposed on a display.

[0002]

2. Description of the Related Art In recent years, a liquid crystal display device having a resistive touch panel (hereinafter referred to as a touch panel) has been used as an input device for inputting with a finger or a pen with the spread of portable information devices.

It has been pointed out that a liquid crystal display device having such a touch panel has a considerably poor appearance when superimposed on a reflection type liquid crystal screen as compared with other input devices such as an electromagnetic induction type and a capacitance type. It had been. FIG. 1 shows a liquid crystal display device with a touch panel in which this is improved.
This will be described with reference to FIG. The liquid crystal cell 1 as shown in FIG.
0, a phase-difference plate 12, a lower polarizer 11, and a reflection plate 13 are laminated from above, or the phase-difference plate 12 is pasted on the upper side of the liquid crystal cell as shown in FIG. A lower polarizing plate 11 and a reflecting plate 13 are attached to the lower side of the cell 10 to form an integrated product. A touch panel is fixed on the liquid crystal cell 10 thus manufactured with a gap. Here, the touch panel has an upper substrate 1 and a lower substrate 4 adhered to each other by a sealing material 8 with a predetermined gap. The upper polarizing plate 9 is attached on the touch panel. In the configuration in which the touch panel is provided between the upper and lower polarizers as described above, if there is a difference in retardation between the upper substrate 1 and the lower substrate 4 forming the touch panel, the light once passing through the polarizer passes through the touch panel, and the phase difference is reduced. Then, the polarization state of each frequency of light changes. This is colored by passing through the polarizing plate again. Therefore, it is necessary to suppress the retardation of the upper substrate 1 and the lower substrate 4 of the touch panel used in such a configuration as low as possible. In this regard, since most of the lower substrate 4 uses glass, there is no retardation and the lower substrate 4 is suitable for use.
On the other hand, a polymer film is often used for the upper substrate 1, and a material generally used for the upper substrate 1 is polyethylene terephthalate (hereinafter, referred to as PET).
It is. Since this PET film is manufactured by biaxial stretching, it has a very large retardation and is not suitable as the upper substrate 1 of this touch panel. A film that has not been stretched in the manufacturing process and that has been manufactured by a method such as casting or extrusion can suppress retardation to a small extent, and thus can be said to be suitable as a material for the upper substrate 1.

In general, the structure of the touch panel is such that the wiring pattern of the upper substrate 1 and the wiring pattern of the lower substrate 4 are electrically connected by a vertically conductive material such as silver paste. Hereinafter, this structure will be described with reference to FIGS. The wiring pattern 2 is formed by printing a silver paste on the short side of the rectangle of the input part 3 formed by etching an ITO film formed on one surface of the upper substrate 1 by sputtering or the like by photoetching. In addition, a silver paste is printed from the long side of the rectangle of the input portion 6 formed by photo-etching the ITO film attached to one surface of the lower substrate 4 to the connection portion of the flexible electric wire, thereby forming the wiring pattern 5. To form When assembling such that the input portions 3 and 6 of the upper substrate 1 and the lower substrate 4 face each other, a flexible electric wire is connected from a position facing the wiring pattern 2 printed on the short side of the input portion 3 of the upper substrate 1. The parts are electrically connected by printing silver paste. The wiring pattern 2 printed on the short side of the input portion 3 of the upper substrate 1 and the wiring pattern 5 on the lower substrate facing the input portion 3 are connected by an upper and lower conductive material 14 in which silver paste or copper balls are mixed with an adhesive. Make it electrically conductive. At this time, the upper substrate 1 and the lower substrate 4 are adhered to each other by the sealing material 8 with a predetermined gap so that the input portions 3 and 6 face each other. Thereafter, the flexible electric wires 7 are attached to the connection portions of the flexible electric wires wired by silver paste printing.

Next, there is a method shown in FIGS. 5 and 6 as a method not using the vertical conductive material 14 used in the above touch panel structure, and this structure will be described with reference to FIGS. 5 and 6. A wiring pattern is formed by printing silver paste from the rectangular short side of the input portion 3 formed by photo-etching the ITO film sputtered on the entire lower surface of the upper substrate 1 to the connection portion of the flexible electric wire 7. Also, the IT provided on the entire upper surface of the lower substrate 4
The wiring pattern 5 is formed by printing a silver paste from the long side of the rectangle of the input portion 6 formed by photo-etching the O film to the connection portion of the flexible electric wire 7. The upper substrate 1 and the lower substrate 4 are placed so that the input portions 3 and 6 face each other, and a flexible electric wire 7 is sandwiched between flexible electric wire connecting portions wired with silver paste as shown in FIG. The upper substrate 1 and the lower substrate 4 are assembled with the sealing material 8. This flexible electric wire 7 has anisotropically conductive adhesive on both sides of the terminal portion on the touch panel side, and the first and third terminals from the left connected to the upper substrate have terminals on the upper surface. 2 from left to connect to lower board
The fourth and fourth terminals have upper and lower terminals, and opposing terminals on both sides thereof are connected by through holes. Thereafter, the flexible electric wire is thermocompression-bonded.

[0006]

However, in the above-mentioned conventional liquid crystal display device with a touch panel, when the upper substrate 1 made of a film shrinks due to a temperature change and humidity, the upper and lower conductive portions and the upper substrate 1 And lower substrate 4
Since the upper substrate 1 and the lower substrate 4 are completely fixed with an adhesive in a portion where the flexible electric wire 7 is connected between the two portions, there is a problem that a change in retardation occurs in the peripheral portion and color unevenness occurs. Had a point.

Therefore, the present invention changes the structure of the touch panel so that the upper substrate 1 and the lower substrate 4 are not completely fixed by an adhesive, so that a liquid crystal display with a touch panel that does not cause color unevenness due to temperature change and humidity. It is intended to provide a device.

[0008]

According to a first aspect of the present invention, there is provided a liquid crystal display device with an input device, comprising: a liquid crystal cell having a twisted-aligned nematic liquid crystal interposed between a pair of electrode substrates disposed opposite to each other; A liquid crystal display device with an input function in which an input device formed by a pair of input substrates having input electrodes on the surface of a substrate to be disposed is disposed between a pair of polarizing plates. A flexible electric wire is connected to the terminal.

According to the above configuration, there is an effect that color unevenness does not occur due to temperature change and humidity.

According to a second aspect of the present invention, in the liquid crystal display device with an input device, a portion of the flexible electric wire connected to each of the input substrates includes a portion to be connected to the one substrate and a portion to be connected to the other substrate. It is characterized by a divided structure.

According to the above configuration, there is an effect that the occurrence of color unevenness is prevented and that only one flexible electric wire that needs to be connected to the external control board is required.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 7 is a view showing a main part of a first embodiment of a liquid crystal display device with a touch panel according to the first aspect of the present invention. The lower substrate 4 is made of glass having a thickness of 0.7 mm made by Nippon Soda, and an ITO film having a surface resistance of 500 to 800 Ω, which is sputtered over the entire upper surface of the lower substrate 4, is photo-etched. Etching,
An input portion 6 and a wiring pattern are formed.

Further, as shown in FIG. 5, from the long side of the rectangle of the input portion 6 of the ITO film to the portion to which the flexible electric wire 7 is connected, an appropriate amount of a hardening material and carbitol are mixed with silver paste as shown in FIG. Is printed by screen printing to form the wiring pattern 5. As the upper substrate 1, a polyester sulfone sun film having a thickness of 100 μm and a retardation of 8 nm was used, and a surface resistance sputtered on the entire lower surface of the upper substrate 1 was 3 μm.
For the ITO film of about 00Ω, the input portion 3 is formed by photoetching similarly to the lower substrate 4. As for the upper substrate 1, a silver paste is screen-printed from the short side of the rectangle of the input portion 3 where the ITO film is etched to the point where the flexible electric wire of the upper substrate 1 is connected to form the wiring pattern 2 as shown in FIG. .

The upper substrate 1 and the lower substrate 4 are mutually input parts 3,
6 were placed so as to face each other, and a sealing material 8 from which a double-sided tape T-4000 made by Sony Chemical was punched was attached to the periphery of the substrate. A heat seal made of Nippon Graphite was used for the flexible electric wire 7 connected to the touch panel.

The touch panel prepared as described above was assembled to the liquid crystal cell 10 as shown in FIG.

Hereinafter, description will be made with reference to FIG. The input portions of the upper substrate 1 and the lower substrate 4 are arranged to face each other, and a sealing material 8 is adhered to the periphery of the substrate, and an upper polarizing plate 9 is provided on the upper surface of the upper substrate 1 as an upper polarizing plate 9 by Nitto Denko. NP
FG1225DU is attached via an adhesive layer. The retardation plate 12 was a uniaxially stretched polycarbonate (hereinafter, referred to as PC) film having a thickness of 120 μm and a retardation of 600 nm, and was adhered to the upper electrode substrate of the liquid crystal cell 10 via an adhesive layer. The upper and lower electrode substrates of the liquid crystal cell 10 were made of glass having a thickness of 0.7 mm.

For the lower polarizing plate 11 and the reflecting plate 13, NPF-F3225M, a polarizing plate with a reflecting plate manufactured by Nitto Denko, was adhered to the lower side of the liquid crystal cell 10 via an adhesive layer. In addition, a width of 3 mm and a height of 0.5 mm between the touch panel and the liquid crystal cell 10.
The silicone rubber was made into an appropriate length and sandwiched outside the display area to form a spacer.

Here, one flexible electric wire 7 is connected only to the upper substrate 1 and the second is connected only to the lower substrate 4, and a sealing material 8 for assembling the upper substrate 1 and the lower substrate 4 is double-sided tape or the like. When the upper substrate 1 contracts due to temperature change or humidity due to the use of the pressure-sensitive adhesive, there is no place where the upper substrate 1 and the lower substrate 4 are adhered to the same place. Since a partial change in tension around the portion fixed to the lower substrate 4 can be suppressed, the occurrence of color unevenness due to a temperature change and humidity can be suppressed.

(Embodiment 2) FIGS. 8 and 9 are views showing a main part of a liquid crystal display device with a touch panel according to a second embodiment of the present invention. To explain the configuration,
The lower substrate 4 is made of glass having a thickness of 1.1 mm manufactured by Nippon Soda, and the input portion 6 is formed by photo-etching an ITO film having a surface resistance of 500 to 800Ω attached to the entire upper surface of the lower substrate 4. I do. The wiring pattern 5 is formed by printing silver paste from the long side of the rectangle of the input portion 6 to the point where the flexible electric wire 7 of the lower substrate 4 is bonded. A PC film having a thickness of 100 μm and a retardation of 10 nm is used for the upper substrate 1, and a surface resistance applied to the entire lower surface of the upper substrate 1 is 400 to 500.
The input portion 3 is formed by photoetching the Ω ITO film in the same manner as the lower substrate 4.

The wiring pattern 2 is formed as shown in FIG. 8 by printing silver paste from the rectangular short side of the input portion 3 of the upper substrate 1 to the point where the flexible electric wire 7 of the lower substrate 4 is connected. The upper substrate 1 and the lower substrate 4 are arranged so that the input portions 3 and 6 are opposed to each other, and a sealing material 8 obtained by punching out a double-sided tape T-4000 made by Sony Chemical is attached to the periphery of the substrate. Sticky. A heat seal made of Japanese graphite is used for the flexible electric wire 7 connected to the touch panel. As shown in FIG. 10, FIG. 11, and FIG. 12, the flexible wire 7 has a fork on the touch panel connection side. One of the two forks has a terminal 7d and an anisotropic conductive adhesive layer 7 on the upper substrate side as shown in the sectional view of FIG.
c, and the back surface is the base 7a of the flexible electric wire.

The other uses a through hole 7e as shown in the sectional view of FIG.
b and the connection terminal 7d on the lower substrate side. An anisotropic conductive adhesive layer 7c is provided on the connection terminal, and an insulating layer 7f is provided on the back surface.

By sandwiching the flexible electric wire between the upper substrate 1 and the lower substrate 4 and pressing them while applying heat, one of the forks is connected only to the upper substrate 1 and the other is connected to the lower substrate 4 only. Can be. In the present embodiment, the heat seal is divided into two branches, but is not limited to two branches.
When there are a plurality of connection portions, the connection portions of the heat seal with the input device can be divided according to the number.

The touch panel prepared as described above was assembled to a liquid crystal cell as shown in FIG. This will be described below with reference to FIG. The input portions of the upper substrate 1 and the lower substrate 4 are arranged to face each other, and a sealing material 8 is provided around the substrate.
NPF-G1225DU manufactured by Nitto Denko is attached as an upper polarizing plate via an adhesive layer on the upper surface of the upper substrate 1 of the touch panel to which is adhered. On the lower side of the liquid crystal cell 10, a retardation plate 12 using a uniaxially stretched PC film having a thickness of 120 μm and a retardation of 600 nm is attached.
Further, NPF-F3225M was adhered to the outside with a polarizing plate 11 with a reflection plate 13 manufactured by Nitto Denko via an adhesive layer.

Also, a silicone rubber having a width of 3 mm and a height of 0.5 mm was provided between the touch panel and the liquid crystal cell 10 at an appropriate length, and was sandwiched outside the display area to form a spacer.

Here, as described above, the touch panel connection side is divided into two branches, one of which is connected only to the upper substrate 1,
The other is connected only to the lower substrate 4, and the adhesive is used for a seal portion for assembling the upper substrate 1 and the lower substrate 4, so that color unevenness due to temperature change and humidity can be achieved without using two flexible electric wires 7. Can be suppressed.

[0027]

As described above, according to the liquid crystal display device with a touch panel of the present invention, it is possible to suppress the occurrence of color unevenness due to temperature change and humidity.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view (1) of a conventional liquid crystal display device with a touch panel.

FIG. 2 is a sectional view (2) of a conventional liquid crystal display device with a touch panel.

FIG. 3 is a perspective view of a touch panel having a conventional structure using a vertical conductive material.

FIG. 4 is a perspective view of a flexible electric wire connection portion of the touch panel of FIG. 3;

FIG. 5 is a perspective view of a touch panel having a conventional structure that does not use a vertical conductive material.

FIG. 6 is a perspective view of a flexible electric wire connection portion of the touch panel of FIG. 5;

FIG. 7 is a perspective view of the structure of the touch panel according to the first embodiment.

FIG. 8 is a perspective view of a structure of a touch panel according to a second embodiment.

FIG. 9 is a perspective view of a flexible electric wire connection portion of the touch panel of FIG. 8;

FIG. 10 is a top view of a flexible electric wire of the touch panel of FIG. 9;

11 is a cross-sectional view of the flexible electric wire of FIG. 10 between A and A ′.

FIG. 12 is a cross-sectional view of the flexible electric wire of FIG. 10 between B and B ′.

[Brief description of reference numerals]

 1. Upper substrate 2. 2. Upper board side wiring pattern Upper board side input part 4. Lower substrate 5. 5. Lower board side wiring pattern 6. Lower board side input part Flexible electric wire 7a. Base material of flexible electric wire 7b. Flexible wire 7c. Anisotropic conductive adhesive layer of flexible electric wire 7d. Connection terminal of flexible electric wire 7e. Flexible wire through hole 7f. 7. Insulation layer of flexible electric wire Seal material 9. Upper polarizing plate 10. Liquid crystal cell 11. Lower polarizing plate 12. Phase plate 13. Reflector plate 14. Vertical conductive material

Claims (3)

[Claims] 1. A liquid crystal cell comprising a twisted-aligned nematic liquid crystal sandwiched between a pair of opposing electrode substrates, and a pair of input substrates having input electrodes on the opposing substrate surfaces. A liquid crystal display device with an input function, wherein the input device and the input device are arranged between a pair of polarizing plates, wherein flexible electric wires are connected to different positions of the input substrates of the input device in a plane. . 2. The flexible wire according to claim 1, wherein a portion to be connected to each of the input substrates is divided into a portion to be connected to the one substrate and a portion to be connected to the other substrate. Item 2. A liquid crystal display device with an input device according to item 1. 3. The liquid crystal display device with an input device according to claim 1, wherein said flexible electric wire is made of heat seal and has a through hole.