JP2000241794A - Touch input type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a visual field angle characteristic and to provide a display screen which is free from a gritty feel when the mirroring-in of a background is prevented by a satin treatment. SOLUTION: This liquid crystal display device is constituted to have a low reflection touch panel arranged with at least a first quarter-wave plate 5, two layers of transparent conductive films 6 facing each other via a spacer 7, a second quarter-wave plate 8 and a polarizing plate 9 successively from a liquid crystal display side on the front surface of the liquid crystal display 2. In such a case, the front surface of the outermost plate of the reflection touch panel 1 is formed as a first satin treated surface 3 and at least one surface among the air contact surfaces (exclusive of the transparent conductive film surfaces) existing between the first quarter-wave plate 5 and the second quarter-wave plate 8 is formed as a fine second satin treated surface 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a touch input type liquid crystal display device having high visibility of a liquid crystal display screen under fluorescent light indoors or under external light outdoors.
In particular, the present invention relates to a display having excellent viewing angle characteristics and a display screen that is not glaring.

[0002]

2. Description of the Related Art Conventionally, liquid crystal display devices have been used in word processors, notebook computers, mobile phones, PDAs, and the like.
(Personal digital assistants), digital cameras and video cameras are widely used. Recently, there is a touch input type liquid crystal display device having a touch panel on the front of a liquid crystal display. The touch panel is
A structure in which two transparent plates on which a transparent conductive film is formed is arranged so that the transparent conductive films face each other via a spacer, and both transparent conductive films insulated by the spacer are part of the panel surface. Are brought into contact by pressing to electrically connect and input.

However, when the input operation of the touch panel is performed in a room with a fluorescent light or the like or outdoors, light from the outside is reflected on the surface of the transparent conductive film, and the display screen is very difficult to see.

Therefore, in order to solve such a problem,
Japanese Patent Application Laid-Open No. H10-48625 discloses that a first quarter-wave plate 5, two transparent conductive films 6 opposed to each other via a spacer 7, and a first quarter-wave plate 5 are sequentially arranged from the liquid crystal display 2 side. A low-reflection touch panel 1 in which at least a second quarter-wave plate 8 and a polarizing plate 9 whose optical axes are orthogonal to each other has been proposed. By forming a circular polarization type anti-reflection filter with the second quarter-wave plate 8 and the polarizing plate 9, it is possible to efficiently cut off the reflection of light incident from the outside on the transparent conductive film 6. If only one second quarter-wave plate 8 is used, linearly polarized light incident for display from the liquid crystal display 2 side is also changed to circularly polarized light.
The first quarter-wave plate 5 whose optical axis is orthogonal to that of the first quarter-wave plate 8 is disposed between the two transparent conductive films 6 and the liquid crystal display 2 to cancel the phase. That is, the light is converted into circularly polarized light by the first quarter-wave plate 5 and then returned to the original linearly polarized light by the second quarter-wave plate 8. Also,
The transparent conductive film 6 may be formed on a transparent substrate such as an optically isotropic glass plate or an optically isotropic transparent resin film, or may be formed on the first １ ／ wavelength plate 5 and the second 1 / 4 wavelength plate 8
May be formed directly on at least one of them.

Some of the general touch panel and the low-reflection touch panel 1 have a matte finish on the front surface of the outermost plate (see FIG. 6). The satin finish is to form irregularities on the surface of the base material by sandblasting, matte coating, or another method.
Background light can be prevented from being reflected by scattering light from the outside toward the front of the panel instead of total reflection.

[0006]

However, the unevenness of the matte-finished surface 11 not only scatters and reflects external light toward the front of the panel but also scatters and transmits light from the liquid crystal display 2. When the satin finish is rough, the interference of the scattered transmitted light and the liquid crystal pixel pitch causes grainy light and dark, and the display screen appears glaring to the observer.

[0007] If the satin finish is made finer, it becomes difficult to produce grainy light and dark, but instead, it becomes difficult to see the liquid crystal display from an oblique direction due to external light scattered and reflected toward the front of the panel. That is, the viewing angle characteristics of the liquid crystal deteriorate.

As described above, since the direction of the roughness that makes it difficult to produce grainy light and darkness is exactly opposite to the direction of the roughness that improves the viewing angle characteristics, either the problem of the viewing angle characteristics or the problem of glare is obtained. It was only possible to give priority to one and sacrifice the other, or to apply a medium-roughness satin finish to improve both the viewing angle characteristics and the glare problem halfway.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems in a touch input type liquid crystal display device in which background reflection is prevented by a satin finish, and has an excellent viewing angle characteristic and a glare on a display screen. There is no touch input type liquid crystal display device.

[0010]

In order to achieve the above object, the present invention provides a liquid crystal display comprising:
Touch input type liquid crystal provided with a low reflection touch panel on the front surface of a liquid crystal display having at least a ４ wavelength plate, two layers of transparent conductive films facing each other via a spacer, a second ４ wavelength plate, and a polarizing plate In a display device,
The front surface of the outermost plate of the low reflection touch panel is a rough first satin-finished surface, and an air contact surface (transparent conductive film) existing between the first quarter-wave plate and the second quarter-wave plate. Excluding surface)
At least one surface is a fine second satin-finished surface.

In the above configuration, the low-reflection touch panel is connected to the first ４ wavelength plate side transparent conductive film and the first conductive film.
The optical isotropic transparent plate was arranged between the wavelength plate and the 波長 wavelength plate.

In each of the above structures, the low-reflection touch panel is provided by disposing an optically isotropic transparent plate between the transparent conductive film on the second quarter-wave plate side and the second quarter-wave plate. It was configured as follows.

In each of the above structures, the low-reflection touch panel is configured such that an optically isotropic transparent plate is arranged on the front surface of the polarizing plate.

The present invention also provides, in order from the liquid crystal display side, a first quarter-wave plate, an optically isotropic transparent plate, two transparent conductive films opposed via a spacer, and a second quarter-wave plate.
In a touch input type liquid crystal display device including a wave plate and a low reflection touch panel having at least a polarizing plate disposed on the front surface of the liquid crystal display, the front surface of the outermost plate of the low reflection touch panel is a rough first matte finish surface, The first quarter-wave plate was configured so that the surface on the transparent conductive film side was a fine second satin-finished surface.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. 1 to 5 are cross-sectional views showing one embodiment of a touch input type liquid crystal display device according to the present invention. In the figure, 1 is a low-reflection touch panel, 2 is a liquid crystal display, 3 is a first matte-finished surface, 4 is a second matte-finished surface, 5 is a first quarter-wave plate, 6 is a transparent conductive film, 7
Is a spacer, 8 is a second quarter-wave plate, 9 is a polarizing plate,
Reference numeral 10 denotes an optically isotropic transparent plate.

As shown in FIGS. 1 to 5, the touch input type liquid crystal display device according to the present invention comprises two layers of transparent conductive layers opposed to each other via a first quarter-wave plate 5 and a spacer 7 from the liquid crystal display 2 side. Low-reflection touch panel 1 including at least film 6, second quarter-wave plate 8, and polarizing plate 9
Is provided on the front surface of the liquid crystal display 2, the front surface of the outermost plate of the low-reflection touch panel 1 is a rough first matte-finished surface 3, and the first quarter-wave plate 5 and the second 1 /
An air contact surface (transparent conductive film 6) existing between the four-wavelength plate 8
(Excluding the surface) is at least one second satin-finished surface 4.

The first quarter wave plate 5 and the second quarter wave plate
The wave plate 8 has a function of converting linearly polarized light into circularly polarized light or substantially circularly polarized light by giving a temporal phase shift (phase difference) to two mutually orthogonal polarized lights obtained by decomposing linearly polarized light. Polarized light in the visible light range (about 400 nm to 70
0 nm) with respect to incident light having a center wavelength (about 550 nm).
It has a function of delaying the phase by four wavelengths.
As the first quarter-wave plate 5 and the second quarter-wave plate 8, a transparent resin plate or film such as polycarbonate, polyarylate, polyether sulfone, polysulfone, norbornene-based resin is uniaxially stretched, and the stretching is performed. Controlling the refractive index in the x direction which is the direction (optical axis direction), the refractive index in the y direction orthogonal to the x direction, and the refractive index in the thickness direction of the film material, ie, the z direction orthogonal to the x direction and the y direction. Then, the above-mentioned phase difference is given.

The second quarter-wave plate 8 forms a circular polarization type anti-reflection filter in combination with the polarizing plate 9 on the front surface thereof. The reflection of the indoor fluorescent lamp and the outside light of the outside pass through the polarizing plate 9 to become linearly polarized light, and the second ４ wavelength plate 8
Is transmitted, the light becomes circularly polarized light.
Even if the light is reflected on the surface, the circularly polarized light again passes through the second quarter-wave plate 8 and becomes linearly polarized light perpendicular to the transmission axis of the polarizing plate 9, so that the reflected light is suppressed. The second quarter-wave plate 8
For the purpose, a device having flexibility to facilitate input with a pen or a finger is used.

The first quarter-wave plate 5 is disposed between the two layers of the transparent conductive film 6 and the liquid crystal display 2 so that the optical axis is orthogonal to the second quarter-wave plate 8. This is to cancel the phase. That is, the linearly polarized light incident on the first quarter-wave plate 5 for display from the liquid crystal display 2 side becomes circularly polarized light by passing through the first quarter-wave plate 5, but becomes second polarized light. After passing through the 波長 wavelength plate 8, the light returns to linearly polarized light again and passes through the polarizing plate 9 for display.

The polarizing plate 9 disposed in front of the second quarter-wave plate 8 forms a circularly-polarized type antireflection filter in combination with the second quarter-wave plate 8. When the low-reflection touch panel 1 is arranged on the liquid crystal display 2 that does not include a polarizing plate for completing a display image in its configuration, it functions as a polarizing plate for completing a display image. The absorption axis of the polarizing plate 9 disposed in front of the second quarter-wave plate 8 is formed to be 45 ° or 135 ° with the optical axis of the second quarter-wave plate 8. In general, as the polarizing plate 9, a polyvinyl alcohol film impregnated with a dichroic dye such as iodine or a dye and stretched is used, and a cellulose- or acrylic-based protective film is coated on both surfaces thereof. The front surface of the polarizing plate 9 can be subjected to antifouling treatment, antireflection treatment, and the like. Here, anti-reflection treatment means applying a low-reflection material using a low-reflection resin such as a fluororesin or a silicon resin, or forming a metal multilayer film by a vacuum evaporation method, a sputtering method, or the like. This is different from pear-skin processing.

The low reflection touch panel 1 has a first 1 /
The transparent conductive film 6 can be directly formed on both the four-wave plate 5 and the second quarter-wave plate 8 (see FIG. 1). Further, the transparent conductive film 6 on the first quarter-wave plate 5 side and the first 1
An optically isotropic transparent plate 10 may be arranged between the 波長 wavelength plate 5 and the transparent conductive film 6 (FIG. 2).
3 and 5). In addition, as shown in FIG.
The transparent conductive film 6 on the ４ wavelength plate 8 side and the second ４ wavelength plate 8
An optically isotropic transparent plate 10 may be arranged between the transparent conductive film 6 and the transparent conductive film 6 to be directly formed (see FIG. 4). Further, the transparent conductive film 6 may not be directly formed on both the first 波長 wavelength plate 5 and the second 波長 wavelength plate 8 (not shown). In any case, the transparent conductive film 6 is formed on the base material and does not exist alone. As the optically isotropic transparent plate 10, an optically isotropic glass plate, an optically isotropic transparent resin plate, a film, or the like is used. In particular, when provided between the transparent conductive film 6 on the side of the second quarter-wave plate 8 and the second quarter-wave plate 8, an optically isotropic transparent resin film is used to facilitate input. It is preferably used.

The low-reflection touch panel 1 has a polarizing plate 9
(See FIG. 5). In this case, the optically isotropic transparent plate 10 is the outermost plate of the low-reflection touch panel 1 to be subjected to the coarse first satin finish. As the optically isotropic transparent plate 10, an optically isotropic glass plate, an optically isotropic transparent resin plate or a film, etc. can be used. It is preferable to use a film. The first satin-finished surface 3 of the optically isotropic transparent plate 10 may be subjected to an antifouling treatment, an anti-reflection treatment, or the like.

As the first satin finish and the second satin finish, sand blasting, embossing, mat coating, etching and the like are used. Particularly recently, a mat coating process in which a resin filler is dispersed is often used, and the matte degree is controlled by the filler particle size and the amount of dispersion. Further, an anti-reflection treatment may be used in combination on these satin-finished surfaces.

The feature of the present invention is that the first satin-finished surface 3 of the outermost plate of the low-reflection touch panel 1 is roughened, and exists between the first quarter-wave plate and the second quarter-wave plate. The second satin-finished surface 4 is to be formed finely. External light is scattered and reflected toward the front of the panel on both the first matte treated surface 3 and the second matte treated surface 4, but is scattered and reflected toward the front of the panel on the second matte treated surface 4. External light is cut by an antireflection filter formed by the second quarter-wave plate 8 and the polarizing plate 9. Therefore, even if the second satin-finished surface 4 is finely formed, the scattered reflected light on the second satin-finished surface 4 does not make it difficult to see the liquid crystal display from an oblique direction. Meanwhile, the first
Since the satin-finished surface 3 is formed roughly, the viewing angle characteristics are extremely excellent.

Further, since the second matte processing surface 4 is formed finely, interference of scattered and transmitted light from the liquid crystal display 2 on the second matte processing surface 4 does not occur. On the other hand, the first matte-finished surface 3 is formed roughly, but the light that has already entered is finely scattered and transmitted by the second matte-finished surface 4. And the display screen is not glazed due to the grainy light and dark caused by the interference of the liquid crystal and the liquid crystal pixel pitch. Note that a plurality of second satin-finished surfaces 4 may be formed.

In FIGS. 1 to 5, the vertices of the convex portions of the second matte-finished surface 4 are drawn so as not to be in contact with the member facing the second matte-finished surface 4. It does not matter.

Examples of the material of the transparent conductive film 6 include metal oxides such as tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide and ITO, and metals such as gold, silver, copper, tin, nickel, aluminum and palladium. Is used. As a method for forming the transparent conductive film 6, a vacuum deposition method,
A sputtering method, an ion plating method, a CVD method, or the like is used. The spacer 7 is formed on the surface of any of the transparent conductive films 6. As the spacer 7,
It can be obtained by forming a transparent photocurable resin into fine dots by a photo process. Also, a large number of fine dots can be formed by a printing method to form a spacer.

Further, in the touch input type liquid crystal display device having the above-described structure, between the member subjected to the satin finish processing and the member opposed to the satin finished surface and between the members having the transparent conductive film 6 directly formed thereon. Except for the above, one or more sets of the front and rear members can be entirely bonded with a transparent adhesive or the like. Also, one or more sets of the front and rear members in the touch input type liquid crystal display device can be bonded only to the periphery with a transparent adhesive or a double-sided tape. Alternatively, they may simply be arranged.

[0029]

The touch input type liquid crystal display device of the present invention has the above-described configuration and operation, and has the following effects.

That is, a liquid crystal display comprising at least a first quarter-wave plate, two transparent conductive films opposing each other via a spacer, a second quarter-wave plate, and a polarizing plate in order from the liquid crystal display side. In a touch input type liquid crystal display device having a reflective touch panel on the front surface of a liquid crystal display, the front surface of the outermost plate of the low reflection touch panel is a rough first satin-finished surface, and the first quarter-wave plate and the second 1/4
At least one of the air contact surfaces (excluding the surface of the transparent conductive film) existing between the wave plate and the air contact surface is a fine second matte-finished surface, and is scattered toward the front of the panel by the second matte-finished surface. The reflected external light is cut by an anti-reflection filter formed by a second quarter-wave plate and a polarizing plate, and an excellent viewing angle characteristic can be obtained by the coarsely patterned first satin finish 3. Can be

In addition, on the first matte processing surface, the light incident from the liquid crystal display side has already been finely scattered and transmitted by the second matte processing surface, so that the interference of the scattered transmitted light and the liquid crystal pixel pitch are reduced. Due to this, no grainy light and dark are caused, and no glare on the display screen occurs.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a touch input type liquid crystal display device according to the present invention.

FIG. 2 is a sectional view showing an embodiment of a touch input type liquid crystal display device according to the present invention.

FIG. 3 is a cross-sectional view illustrating an embodiment of a touch input type liquid crystal display device according to the present invention.

FIG. 4 is a sectional view showing an embodiment of a touch input type liquid crystal display device according to the present invention.

FIG. 5 is a sectional view showing an embodiment of a touch input type liquid crystal display device according to the present invention.

FIG. 6 is a cross-sectional view illustrating one embodiment of a touch input type liquid crystal display device according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Low-reflection touch panel 2 Liquid crystal display 3 First satin finished surface 4 Second satin finished surface 5 First 1/4 wavelength plate 6 Transparent conductive film 7 Spacer 8 Second 1/4 wavelength plate 9 Polarizing plate 10 Optical Isotropic transparent plate 11 Nashiji treated surface

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H091 FA08X FA11X FA31X FB02 FC25 FC26 FD10 LA03 2H093 NC72 ND04 ND60 NE06

Claims (5)

[Claims] 1. The first 1 /
Touch input type liquid crystal display having a low reflection touch panel on the front surface of a liquid crystal display having at least a four-wavelength plate, two transparent conductive films facing each other via a spacer, a second quarter-wave plate, and a polarizing plate In the device, the front surface of the outermost plate of the low-reflection touch panel is a rough first satin-finished surface, and an air contact surface existing between the first quarter-wave plate and the second quarter-wave plate ( A touch input type liquid crystal display device characterized in that at least one surface of the touch input type liquid crystal display device (excluding the surface of the transparent conductive film) is a fine second satin-finished surface. 2. The low-reflection touch panel has an optically isotropic transparent plate disposed between the first quarter-wave plate side transparent conductive film and the first quarter-wave plate. 2. The touch input type liquid crystal display device according to 1. 3. The low-reflection touch panel has an optically isotropic transparent plate disposed between the transparent conductive film on the second quarter-wave plate side and the second quarter-wave plate. 1 or Claim 2
The touch input type liquid crystal display device according to any one of the above. 4. The touch-input type liquid crystal display device according to claim 1, wherein the low-reflection touch panel has an optically isotropic transparent plate disposed in front of the polarizing plate. 5. The first 1/1 in order from the liquid crystal display side.
A low-reflection touch panel including at least a four-wavelength plate, an optically isotropic transparent plate, two layers of transparent conductive films facing each other via a spacer, a second quarter-wave plate, and a polarizing plate is provided on the front surface of a liquid crystal display. In the touch input type liquid crystal display device provided in the above, the front surface of the outermost plate of the low-reflection touch panel is a rough first satin-finished surface, and the surface of the first quarter-wave plate on the side of the transparent conductive film is fine. A touch input type liquid crystal display device characterized by having a satin finish surface.