JP2004227010A - Touch input type liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch input type liquid crystal display (LCD) device with low reflectance, high contrast, and high visibility. <P>SOLUTION: In the touch input mode LCD device equipped with an LCD on the lower side of a transparent touch panel, an upper side polarizing plate is disposed on an upper surface of the transparent touch panel, comprising an upper side optical retardation film imparting 1/4 wavelength retardation to incident light with a wavelength equal to the center wavelength of the visible ray region and equipped with a movable electrode part on the lower surface thereof and a lower side optical retardation film imparting 1/4 wavelength retardation to the incident light with the wavelength equal to the center wavelength of the visible ray region and equipped with a fixed electrode part on the upper surface thereof disposed via a space layer, a lower side polarizing plate is disposed on the lower surface of the LCD, an optically isotropic film is disposed between the fixed electrode part and the lower side optical retardation film wherein the fixed electrode part is directly formed on the optically isotropic film. Besides thermal distortion temperatures of the upper side optical retardation film and the optically isotropic film are 150°C or higher. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a touch input type liquid crystal display device which suppresses reflected light such as fluorescent light indoors and reflected light due to external light outdoors and has high contrast and high visibility.

  2. Description of the Related Art Conventionally, as a configuration of a touch input type liquid crystal display device, a liquid crystal display 2 is provided below a transparent touch panel 1, and the transparent touch panel 1 is configured such that a movable sheet 20 and a fixed sheet 21 are arranged via a space layer 7. In some cases, upper and lower polarizers 8 and 9 are disposed on the upper and lower surfaces of the liquid crystal display 2 (see FIG. 17).

  Further, in order to increase the contrast, the upper polarizing plate 8 may be disposed on the upper surface of the movable sheet 20 of the transparent touch panel 1 instead of disposing the upper polarizing plate 8 on the upper surface of the liquid crystal display 2 (see FIG. 18). .

  However, in the touch input type liquid crystal display device having the above configuration, in a room such as a fluorescent lamp 504 as shown in FIG. 19 or outdoors as shown in FIG. When an input operation is performed on the personal computer 502 or the portable terminal 500 with the pen 503 or 501, the interface between the spatial layer of the transparent touch panel 1 of the liquid crystal display device and the fixed electrode portion provided on the upper surface of the fixed side sheet and the transparency. The display screen was very difficult to see due to the reflection of light at two places on the top surface of the touch panel 1. This is because, when light passes from a medium having a low refractive index to a medium having a high refractive index, the larger the difference between the refractive indexes, the more the light is reflected at the interface.

  In the case where the upper polarizing plate 8 is arranged on the upper surface of the movable sheet 20 of the transparent touch panel 1, there is a method of forming the upper surface of the upper polarizing plate 8 in a satin shape to prevent reflected light, but it is necessary to sufficiently suppress the reflected light. Can not.

  Accordingly, it is an object of the present invention to provide a touch-input type liquid crystal display device with low reflection, high contrast, and high visibility even in a room with a fluorescent light or the like or outdoors, by solving the above problems. It is.

  In order to achieve the above object, the present invention provides a touch-input type liquid crystal display device having a liquid crystal display (2) below a transparent touch panel (1), wherein the liquid crystal display device is a quarter of incident light having a central wavelength in the visible region. An upper optical retardation film (4) having a phase delay of wavelength and having a movable electrode portion (3) on the lower surface, and a phase retarder of 1/4 wavelength for incident light of the center wavelength in the visible region and having an upper surface. An upper polarizing plate (8) is disposed on the upper surface of the transparent touch panel (1) in which a lower optical retardation film (6) having a fixed electrode portion (5) is disposed via a spatial layer (7). A lower polarizing plate (9) is disposed on a lower surface of the liquid crystal display (2), and an angle between an optical axis of the upper optical retardation film (4) and an absorption axis of the upper polarizing plate (8) is about 45.゜ and below The angle between the optical axis of the optical retardation film (6) and the linearly polarized light emitted from the liquid crystal display (2) and the linearly polarized light to be emitted from the device surface is about 45 °, and the upper optical retardation film is formed. The angle between the optical axis of (4) and the optical axis of the lower optical retardation film (6) is about 90 °, and a straight line to be emitted from the device surface out of the linearly polarized light emitted from the liquid crystal display (2). The angle between the polarized light and the absorption axis of the upper polarizing plate (8) was 90 °. According to the first aspect of the present invention, the fixed electrode section (5) is directly formed on the lower optical retardation film (6), and the upper optical retardation film (4) and the lower optical retardation film (4) are formed. The optical retardation film (6) was configured so that the heat deformation temperature was 150 ° C. or higher.

  Further, according to the second aspect of the present invention, a glass substrate (11) having optical isotropy is provided between the fixed electrode portion (5) and the lower optical retardation film (6). The fixed electrode portion (5) was directly formed on the anisotropic glass substrate (11), and the upper optical retardation film (4) had a heat deformation temperature of 150 ° C. or more. .

  According to the third aspect of the present invention, an optically isotropic film (12) is provided between the fixed electrode part (5) and the lower optical retardation film (6), and the optically isotropic film is provided. The fixed electrode portion (5) is directly formed on (12), and the upper optical retardation film (4) and the optically isotropic film (12) have a heat deformation temperature of 150 ° C. or more. did.

(Deletion)

  Further, in the first aspect of the present invention, the upper optical retardation film (4) and the lower optical retardation film (6) are configured so that the heat deformation temperature thereof is 170 ° C. or more.

(Deletion)

  Further, in the second aspect of the present invention, the upper optical retardation film (4) is configured so that the heat deformation temperature thereof is 170 ° C. or higher.

(Deletion)

  Further, in the third aspect of the present invention, the upper optical retardation film (4) and the optically isotropic film (12) are configured such that the heat deformation temperature is 170 ° C. or higher.

  In each aspect of the present invention, a transparent resin plate (16) having optical isotropy is arranged between the transparent touch panel (1) and the liquid crystal display (2).

  In the third aspect of the present invention, a transparent resin plate (16) having optical isotropy is arranged between the optical isotropic film (12) and the lower optical retardation film (6). It was configured to be.

  In each embodiment of the present invention, the thickness of the upper optical retardation film (4) is set to be 50 μm or more and 150 μm or less.

  In each embodiment of the present invention, the member on which the fixed electrode portion (5) is directly formed and the liquid crystal display (2) or all of the members between them are formed of a transparent adhesive layer or a transparent removable layer. It was configured so that it was completely adhered by a sheet.

  Further, the touch input type liquid crystal display device of the present invention is configured such that a transparent film (22) having low moisture permeability and excellent dimensional stability is bonded to the upper surface of the upper polarizing plate (8) ( Fourth embodiment: the fixed electrode portion is directly formed on the lower optical retardation film, the fifth embodiment: the fixed electrode portion is formed directly on the glass substrate, and the sixth embodiment: the fixed electrode portion is formed directly on the optically isotropic film.

  Further, in the fourth to sixth aspects of the present invention, a low reflection processing layer (23) is provided on the upper surface of the transparent film (22) bonded to the upper surface of the upper polarizing plate (8).

  In the fourth to sixth aspects of the present invention, an antifouling treatment layer (24) is provided on the upper surface of the transparent film bonded to the upper surface of the upper polarizing plate (8).

  Further, in the fourth to sixth aspects of the present invention, a hard coat treatment layer (25) is provided on the upper surface of the transparent film bonded to the upper surface of the upper polarizing plate (8).

  The present invention also relates to a method for manufacturing a touch-input type liquid crystal display device for manufacturing the above-mentioned touch-input type liquid crystal display device, the method for removing a residual solvent from the film material of the upper optical retardation film (4). Forming a transparent conductive film of the movable electrode portion (3) directly on the film material after heat treatment for performing the heat treatment for reducing dimensional errors in forming lead wires. A movable sheet is obtained through a step of forming a lead wire of the movable electrode section (3), a step of curing a binder of ink forming the lead wire and a heat treatment for removing a solvent, and the lower optical retardation film (6) is obtained. Forming a transparent conductive film of the fixed electrode portion (5) directly on the film material after performing a heat treatment for removing a residual solvent in the film material of (a). After the heat treatment for reducing the dimensional error at the time of forming the lead wire, the step of forming the lead wire of the fixed electrode portion (5), the heat treatment for curing the binder of the ink forming the lead wire and removing the solvent are performed. The fixed side sheet is obtained through the applying step, the movable side sheet and the fixed side sheet are bonded, and then the upper polarizing plate (8) is bonded to the upper surface of the upper optical retardation film (4) of the movable side sheet. After the combination, a pressure defoaming treatment was performed, and the fixed side sheet was bonded to a liquid crystal display to manufacture a touch input type liquid crystal display device.

  The present invention also relates to a touch input type liquid crystal display device manufacturing method for manufacturing the touch input type liquid crystal display device, wherein the heat treatment for removing residual solvent in the film material of the upper optical retardation film (4). Forming a transparent conductive film of the movable electrode portion (3) directly on the film material, performing a heat treatment to reduce a dimensional error in forming a lead wire, and then forming the movable electrode portion. The movable side sheet is obtained through the step (3) of forming a lead wire, the step of curing the binder of the ink having formed the lead wire and the step of removing the solvent, and forming the movable side sheet on the glass substrate (11) having optical isotropy. A step of directly forming a transparent conductive film of the fixed electrode portion (5), a step of forming a lead wire of the fixed electrode portion (5), a binder of ink forming the lead wire A fixed-side sheet is obtained through a step of performing a heat treatment of curing and solvent removal, the movable-side sheet and the fixed-side sheet are bonded, and then the upper side of the movable-side sheet is placed on the upper surface of the upper optical retardation film (4). After laminating the polarizing plate (8), applying pressure defoaming treatment, and laminating the fixed side sheet with the liquid crystal display via the lower optical retardation film (6) between the fixed side sheet and the touch input type liquid crystal. A display device was configured to be manufactured.

  The present invention also relates to a touch input type liquid crystal display device manufacturing method for manufacturing the touch input type liquid crystal display device, wherein the heat treatment for removing residual solvent in the film material of the upper optical retardation film (4). Forming a transparent conductive film of the movable electrode portion (3) directly on the film material, performing a heat treatment to reduce a dimensional error in forming a lead wire, and then forming the movable electrode portion. The movable side sheet is obtained through the step (3) of forming a lead wire, the step of curing the binder of the ink forming the lead wire and performing the heat treatment of removing the solvent, and obtaining the movable side sheet in the film material of the optically isotropic film (12). A step of directly forming a transparent conductive film of the fixed electrode portion (5) on the film material after a heat treatment for removing the residual solvent; After performing a heat treatment for reducing the process error, forming a lead wire of the fixed electrode part (5), curing the binder of the ink forming the lead wire, and performing a heat treatment for removing the solvent, and then the fixing side. After obtaining a sheet, the movable side sheet and the fixed side sheet are bonded together, and then the upper polarizing plate (8) is bonded to the upper surface of the upper optical retardation film (4) of the movable side sheet, and then pressed. A defoaming treatment was performed, and the fixed side sheet was bonded to a liquid crystal display via the lower optical retardation film (6) therebetween to manufacture a touch input type liquid crystal display device.

  Further, in the method of manufacturing a touch input type liquid crystal display device of the present invention, the heat treatment for removing the residual solvent in each of the film materials is performed at 150 ° C. or more.

  Further, in the manufacturing method of the touch input type liquid crystal display device of the present invention, the heat treatment for reducing the dimensional error at the time of forming the lead wire is performed at 100 ° C. or more and less than 130 ° C.

  In the method of manufacturing a touch input type liquid crystal display device according to the present invention, the heat treatment for curing the binder of the ink forming the lead wire and removing the solvent is performed at 100 ° C. or more and less than 150 ° C.

  Further, in the method of manufacturing a touch input type liquid crystal display device of the present invention, the pressure defoaming treatment is performed at 40 to 80 ° C., 4 to 9 kg / cm 2 for 10 to 120 minutes.

  In the method of manufacturing a touch input type liquid crystal display device according to the present invention, at least one of the movable electrode portion (3) and the fixed electrode portion (5) is provided with an electrode lead portion in advance, and the movable sheet is fixed to the movable side sheet. After laminating the side sheets, it was configured to be pressure-bonded to the connector (40) at 120 ° C or more and less than 170 ° C via an anisotropic conductive adhesive.

  The touch input type liquid crystal display device according to the present invention has the above configuration and operation, and thus has the following effects.

  That is, by arranging the angle between the absorption axis of the upper polarizing plate and the optical axis of the upper optical retardation film at about 45 °, the light becomes circularly polarized light or substantially circularly polarized light, enters the space layer of the transparent touch panel, and is reflected. The circularly or substantially circularly polarized light again passes through the upper optical retardation film and becomes linearly polarized light perpendicular to the transmission axis of the upper polarizing plate, so that reflected light is suppressed. Here, the absorption axis of the upper polarizing plate 8 is an axis parallel to the stretching direction of the film material. The light passing through the upper polarizing plate 8 is polarized and emitted from the upper polarizing plate 8 as linearly polarized light only in a direction orthogonal to the absorption axis. Note that an axis perpendicular to the absorption axis is called a transmission axis. In order for the upper polarizing plate 8 to transmit linearly polarized light, the transmission axis and the direction must match. Linearly polarized light whose directions do not match cannot pass through the upper polarizing plate 8.

  Also, it is desired that the linearly polarized light emitted from the liquid crystal display be emitted from the device surface so that the optical axis of the lower optical retardation film is at an angle of about 90 ° with respect to the optical axis of the upper optical retardation film. By disposing between the transparent touch panel and the liquid crystal display at an angle of about 45 ° with respect to the linearly polarized light, coloring of the display screen when viewed from the observer side is suppressed, and high contrast and no coloring A display screen is obtained. The linearly polarized light emitted from the liquid crystal display and desired to be emitted from the surface of the device has an angle of 90 ° with the absorption axis of the upper polarizing plate.

  Further, in the touch input type liquid crystal display device, reflection of light on the uppermost surface is suppressed by performing low reflection processing on the uppermost surface.

  According to the above improvement, the liquid crystal display including the transparent touch panel according to the present invention can obtain a display screen with low reflection, high contrast, and excellent visibility even in a room having a fluorescent light or the like or outdoors.

  Since the present invention has the above-described configuration and operation, the upper polarizing plate and the layers behind the upper polarizing plate suppress reflected light such as fluorescent light indoors or reflected light due to external light outdoors and have high contrast. Thus, a liquid crystal display device of a touch input type with high visibility can be obtained.

  Furthermore, when a transparent film is stuck on the upper surface of the upper polarizing plate, the following effects are exhibited by the transparent film. That is, by adhering the transparent film to the upper surface of the upper polarizing plate, the durability of the surface is improved, and the surface of the upper polarizing plate can be prevented from being damaged by pen or finger input. In addition, by attaching a transparent film to the upper surface of the upper polarizing plate, it is possible to prevent moisture absorption from the surface of the upper polarizing plate, thereby suppressing the contraction, expansion, and distortion of the upper polarizing plate. The change in retardation value of the laminated upper optical retardation film is suppressed, color unevenness does not occur, and the antireflection function is not impaired.

  Hereinafter, a touch input type liquid crystal display device and a method of manufacturing the same according to various embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a sectional view showing a resistive touch type liquid crystal display device (transmission type TN) according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view of the liquid crystal display device of FIG. 1, FIG. 3 is a schematic sectional view of the liquid crystal display device of FIG. 1, and FIG. It is explanatory drawing for demonstrating the state suppressed, and FIG. 5 is explanatory drawing of a backlight light guide plate.

  FIG. 6 is a sectional view showing a touch input type liquid crystal display device (transmission type STN) according to a second embodiment of the present invention.

  FIG. 7 is a sectional view showing a touch input type liquid crystal display device (reflection type STN) according to a third embodiment of the present invention.

  FIG. 8 is an explanatory diagram of a transmission axis direction and an optical axis direction in the touch input type liquid crystal display device (TN) according to the embodiment of the present invention.

  FIG. 9 is a cross-sectional view illustrating a touch input type liquid crystal display device (transmission type TN) according to a modification of the first embodiment.

  FIG. 10 is a cross-sectional view illustrating a touch input type liquid crystal display device (reflection type STN) according to a modification of the third embodiment.

  In the figure, 1 is the transparent touch panel, 2 is a liquid crystal display, 3 is a movable electrode part, 4 is an upper optical retardation film, 5 is a fixed electrode part, 6 is a lower optical retardation film, 7 is a space layer, and 8 is a spatial layer. Upper polarizing plate, 9 is a lower polarizing plate, 10 is a spacer, 11 is a glass substrate, 12 is an optically isotropic film, 13 is a backlight light guide plate, 14 is an optical compensation retardation plate, 15 is a reflection plate, and 16 is a reflection plate. Each shows a transparent resin plate.

  FIG. 5 shows an edge light surface emitting device having a general structure of the backlight light guide plate 13. In FIG. 5, 13a denotes a linear light source, 13c denotes a light guide plate, 13d denotes a light reflection plate, 13e denotes a light scattering layer, and 13b denotes a diffusion sheet. Light guided from the linear light source 13a into the light guide plate 13c is emitted from the front surface (the upper surface in FIG. 5) of the light guide plate 13c by the light scattering layer 13e and the light reflecting plate 13d formed on the lower surface of the light guide plate 13c. . Further, the light emitted from the light guide plate 13c is uniformly and entirely emitted from the surface by the diffusion sheet 13b provided on the upper surface of the light guide plate 13c.

  The movable electrode section 3 is composed of a flexible transparent conductive film 3a and lead wires 3b. The material for forming the movable electrode portion 3 is mainly a metal oxide such as tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide, or indium tin oxide (ITO), or a metal oxide thereof. There are a composite film, gold, silver, copper, tin, nickel, aluminum, palladium, and the like.

  The upper optical retardation film 4 has a function of changing the linearly polarized light into circularly polarized light or substantially circularly polarized light by giving a time phase shift to the two orthogonally polarized light components obtained by decomposing the linearly polarized light. Is a transparent film having a function of delaying the phase by １ ／ wavelength with respect to the incident light having the central wavelength in the visible region. That is, by using the upper optical retardation film 4, one of two orthogonally polarized light components obtained by decomposing the linearly polarized light causes a phase delay of about の of the center wavelength of about 550 nm in the visible region, that is, about 138 nm. . In this case, if the amplitudes of the polarized light of the two orthogonal components are equal, the light becomes circularly polarized light, otherwise, the light becomes elliptically polarized light. Here, "the center wavelength of the visible region is about 550 nm" is, for example, the center wavelength of the visible region is about 550 nm, and the reason why the center wavelength is about 550 nm is as follows. That is, when the center wavelength of the visible region is considered in relation to the human luminosity curve, the human visible light region is about 400 nm to 700 nm, and the luminosity peak is at about 550 nm. This is because by suppressing light reflection at a wavelength of 550 nm, reflection can be prevented from being sensed by human eyes.

  The upper optical retardation film 4 also has a function as an input unit for a pen or a finger of a touch panel, and therefore must have flexibility to facilitate input.

  Further, since the upper optical retardation film 4 is subjected to a high temperature treatment when forming the movable electrode portion 3 and forming the circuit, the film material used is required to have a heat resistance of 150 ° C. or more. In a film material having a low heat distortion temperature (in other words, less than 150 ° C. as described later), the retardation value, which is the value of the phase delay of the two-component polarization, changes due to the high-temperature treatment, and the touch according to the embodiment of the present invention described above. In the configuration of the input type liquid crystal display device, the visibility of the display screen is inferior. However, it has been found that a film material having a higher heat deformation temperature (in other words, 150 ° C. or higher as described later) has a change in retardation value during high-temperature treatment reduced to a practically negligible level. Examples of such a material include a uniaxially stretched polymer film having a heat deformation temperature of 150 ° C. or more, for example, polyarylate, polyether sulfone, norbornene-based resin, and polysulfone. Particularly, as the film material, a uniaxially stretched polyarylate, polyethersulfone, or polysulfone film having a heat deformation temperature of 170 ° C. or more is preferable.

  The reason why the film material having a heat deformation temperature of 150 ° C. or more is used as the film material of the upper optical retardation film 4 and the reason that the heat material preferably has a heat deformation temperature of 170 ° C. or more will be described in detail below. .

  First, the reason why a film material having a heat distortion temperature of 150 ° C. or more is used as the film material of the upper optical retardation film 4 will be described below.

  Generally, when heat equal to or higher than the thermal deformation temperature of the film material of the upper optical retardation film 4 is applied to the film material of the upper optical retardation film 4, the heat causes the film material of the upper optical retardation film 4 to be deformed or distorted. Causes deterioration. In this case, the upper optical retardation film 4 cannot maintain a phase difference (retardation) of １ ／ wavelength, and as a result, it becomes impossible to suppress reflection or obtain an accurate image. Therefore, the film material that can be used is limited by the temperature of each heat treatment described below performed on the upper optical retardation film 4 in the present embodiment.

  In addition, even if the heat distortion temperature of the film material of the upper optical retardation film 4 is low (for example, less than 150 ° C.), if the heat treatment is performed at a temperature lower than the low heat distortion temperature, the film of the upper optical retardation film 4 due to the heat No deformation or deterioration of the material occurs, but in this case, the heat treatment naturally becomes meaningless, that is, various effects obtained by the heat treatment described later cannot be obtained. The heat treatment for manufacturing the upper optical retardation film 4 will be described below in the order of steps, that is, in the order of heat treatment (1) to heat treatment (3).

Heat treatment (1)
Usually, in order to continuously manufacture a large number of upper optical retardation films 4 of a liquid crystal display device, one film material corresponding to one or an arbitrary number of upper optical retardation films 4 is continuously connected. A roll-shaped film material is prepared. Before forming a transparent conductive film constituting a part of the movable electrode part 3 on such a roll-shaped film material, it is necessary to perform a heat treatment at a temperature as high as possible for a predetermined time in order to remove the residual solvent in the film material. There is. This is because the presence of a residual solvent in the film material makes it impossible to stably form the transparent conductive film on the film material. Therefore, after removing the residual solvent in the film material, in order to form a transparent conductive film having excellent stability and high strength on the film material, the residual solvent is kept at a high temperature of 150 ° C. or more for a predetermined time. It is necessary to form a transparent conductive film on a film material after performing a heat treatment for removing the film. The reason is that the residual solvent cannot be sufficiently removed at a temperature lower than 150 ° C., and a transparent conductive film having excellent stability and high strength cannot be formed on a film material at all. Therefore, in order to remove the residual solvent in the film material, the heat deformation temperature of the film material, that is, the upper optical retardation film 4 needs to be 150 ° C. or more.

Heat treatment (2)
After forming the transparent conductive film on the film material as described above, in order to form a desired circuit connected to the already formed transparent conductive film on the roll-shaped film material, first, The film material in the form of a roll is cut into single sheets to form a film material sheet for the upper optical retardation film 4. Then, if necessary, a heat treatment is performed on the film material sheet to minimize dimensional errors during circuit formation. This heat treatment is desirably performed at 100 ° C. or higher and lower than 130 ° C. for about 1 hour. Therefore, the heat distortion temperature of the film material needs to be 130 ° C. or higher, and preferably 150 ° C. or higher is sufficient.

Heat treatment (3)
At the time of forming a circuit on the film material sheet, high-temperature drying is performed to cure the binder and remove the solvent of the ink that has formed the desired circuit connected to the transparent conductive film. This high-temperature drying is performed at 100 ° C. or higher and lower than 150 ° C. for 30 to 60 minutes. Therefore, the heat deformation temperature of the film material needs to be 150 ° C. or higher.

  As described above, since the various heat treatments (1) to (3) are performed, the film material of the upper optical retardation film 4 may be a uniaxially stretched polymer film having a heat deformation temperature of 150 ° C. or more, For example, polyarylate, polyether sulfone, polysulfone, norbornene-based resin and the like can be mentioned. As the film material, a uniaxially stretched polyarylate, polyether sulfone, or polysulfone film having a heat deformation temperature of 170 ° C. or more is particularly preferable. As described above, various heat treatments can be performed if the heat deformation temperature of the film material is 150 ° C. or higher. However, by performing the heat treatment at 170 ° C. or higher before forming the transparent conductive film, the crystallization of the transparent conductive film (ie, high strength) Is performed sufficiently, so that a more stable transparent electrode can be obtained. In order to perform the heat treatment at 170 ° C. or higher, the heat deformation temperature of the film material needs to be 170 ° C. or higher which is higher than the heat treatment temperature.

  The thickness of the upper optical retardation film 4 is preferably 50 μm or more and 150 μm or less. If the thickness of the upper optical retardation film 4 exceeds 150 μm, the total thickness combined with the upper polarizer 8 becomes thick, and the input with a finger or a pen becomes heavy, and characters cannot be input clearly. Further, if the thickness of the upper optical retardation film 4 is less than 50 μm, the film itself will have no rigidity, and wrinkles and undulations will occur during circuit formation, making it difficult to bond the film to the upper polarizing plate 8. Therefore, the thickness of the upper optical retardation film 4 is preferably 50 μm or more and 150 μm or less. More preferably, it is 75 μm or more and 125 μm or less. It is more preferable that the upper optical retardation film 4 has a thickness of 75 μm or more and 125 μm or less because the film has a thickness of 50 μm or more and less than 75 μm, and the film does not wrinkle. Ripples with valleys cannot be completely eliminated. By setting the thickness of the upper optical retardation film 4 to 75 μm or more, the waving can be completely eliminated. Further, even when the thickness is 125 μm or more and less than 150 μm, the input with a pen or a finger becomes light and a character can be input clearly, but when the thickness is less than 125 μm, a character can be input particularly clearly.

  1, 6, 7, 9, and 10, the member around the space layer 7 sandwiched between the movable electrode 3 and the fixed electrode 5 is an upper optical member that supports the electrodes 3 and 5. It is a double-sided tape 19 for bonding the retardation film 4 and the base material on which the fixed electrode portion 5 is directly formed. An adhesive material may be used instead of the double-sided tape 19. Examples of the adhesive used in the adhesive or the double-sided tape 19 include acrylic, epoxy, urethane, and copolymers thereof, and the double-sided tape is preferably Nitto Denko 532, for example.

  The fixed electrode section 5 is composed of a transparent conductive film 5a, a lead wire 5b, and the like, like the movable electrode section 3. As a material for forming the fixed electrode portion 5, an oxide such as tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide, or indium tin oxide (ITO), or a composite mainly containing these metal oxides There are films, gold, silver, copper, tin, nickel, aluminum, aluminum, palladium, and the like.

  In the first embodiment, a lower optical retardation film 6 (see FIG. 1) is used as a base material on which the fixed electrode portion 5 is directly formed.

  On the other hand, in the second embodiment, a transparent glass substrate 11 having optical isotropy (see FIG. 6) is used as a base on which the fixed electrode portion 5 is directly formed.

  In the third embodiment, the transparent optically isotropic film 12 (see FIG. 7) is used as a base material on which the fixed electrode portion 5 is directly formed.

  Similarly to the upper optical retardation film 4, the base material of the second embodiment and the third embodiment is also subjected to high temperature treatment when forming the fixed electrode portion 5 and forming the circuit.

  The characteristics required as the material of the lower optical retardation film 6 are the case where the transparent conductive film constituting a part of the fixed electrode portion 5 is provided thereon as in the first embodiment, and the case where the second and third films are formed. Since this is different from the case where the transparent conductive film constituting a part of the fixed electrode unit 5 is not provided thereon as in the embodiment, the description will be made separately below.

  First, when a transparent conductive film constituting a part of the fixed electrode portion 5 is provided thereon as in the first embodiment, that is, the lower optical retardation film 6 includes the fixed electrode portion 5 including the transparent conductive film. In the case of directly forming, the following characteristics are required.

  Examples of the material of the lower optical retardation film 6 include a uniaxially stretched transparent polymer film having a heat deformation temperature of 150 ° C. or more, such as polyarylate, polyether sulfone, polysulfone, or norbornene-based resin. . This is because, when the heat distortion temperature is lower than 150 ° C., the heat treatment at the time of manufacturing the touch panel causes a change in retardation in a portion where the liquid crystal display is visually recognized on the touch panel, so that a sufficiently low reflection effect cannot be obtained. Further, even if the light required for forming a pixel cannot be emitted due to a change in retardation, or unnecessary light is emitted for forming a pixel, and an accurate image cannot be formed. is there. The heat treatment performed on the lower optical retardation film 6 on which the fixed electrode portion 5 is directly formed is each of the heat treatments (1) to (3) as described for the upper optical retardation film 4. Like the upper optical retardation film 4, the material of the lower optical retardation film 6 preferably has a heat deformation temperature of 170 ° C. or more to sufficiently crystallize the transparent conductive film.

  Next, when the transparent conductive film is not provided thereon as in the second and third embodiments, that is, the fixed electrode portion 5 including the transparent conductive film has optical isotropy as in the second embodiment. The following characteristics are required when formed on the glass substrate 11 or when the fixed electrode portion 5 including the transparent conductive film is formed on the optically isotropic film 12 as in the third embodiment. Is done.

  Examples of the material of the lower optical retardation film 6 on which the transparent conductive film is not provided include a uniaxially stretched transparent polymer film having a heat deformation temperature of 130 ° C. or more, for example, polycarbonate, polyarylate, polyether sulfone, Norbornene-based resins, polysulfone, and the like can be given. In this case, since the heat treatments (1) to (3) as described for the production of the upper optical retardation film 4 are not relevant, it is not necessary to have a heat deformation temperature of 150 ° C. or more. However, a heat distortion temperature of 130 ° C. or more is still required. This is because if the heat distortion temperature is lower than 130 ° C., the retardation value may change over time.

  On the other hand, as the optically isotropic film 12 forming the fixed electrode portion 5, an unstretched polymer film having a heat deformation temperature of 150 ° C. or more, for example, polyarylate, polyether sulfone, polysulfone, or norbornene-based resin Are preferred. This is because the optically isotropic film 12 does not have a retardation value, so there is no problem in that respect. Nevertheless, each heat treatment (1) as described in the production of the upper optical retardation film 4 is performed. This is because the steps (3) to (3) require a heat deformation temperature of 150 ° C. or more that can withstand this.

  As described above, in the first and third embodiments, by using the lower optical retardation film 6 and the optically isotropic film 12, the case where the glass substrate 11 having optical isotropic is used in the second embodiment is different from that in the first and third embodiments. In comparison, the overall thickness of the transparent touch panel 1 is reduced, and the thickness and weight of the touch input type liquid crystal display device can be reduced. For example, in the case of the second embodiment in which the fixed electrode portion 5 is formed on the glass substrate 11 having optical isotropy, in the case of the first embodiment in which the lower optical retardation film 6 is used, or in the case of optical isotropy. In the case of the third embodiment using the film 12, the thickness of the lower optical retardation film 6 or the optical isotropic film 12 is 0.7 mm while the thickness of the optically isotropic glass substrate 11 is 0.7 mm. Can be set to 0.075 mm, and the thickness of the base material for the fixed electrode in the case of the first embodiment or the third embodiment is about 1/10 of the thickness of the second embodiment. On the other hand, when the glass substrate 11 having optical isotropy is used as in the case of the second embodiment, the pressing of a finger or a pen or the like is performed as compared with the case of the first embodiment or the third embodiment. Stability and durability are more stable.

  As a modification of the first embodiment, when priority is given to pressing stability and durability similar to the glass substrate 11 having optical isotropy over thinning in the first embodiment, the transparent touch panel 1 It is preferable to dispose a transparent resin plate 16 having optical isotropy between the liquid crystal display 2 and the liquid crystal display 2 (see FIG. 9).

  As a modification of the third embodiment, in the third embodiment, when priority is given to pressing stability and durability similar to the glass substrate 11 having optical isotropy over thinning, the optical isotropy is used. It is preferable to dispose a transparent resin plate 16 having optical isotropy between the conductive film 12 and the lower optical retardation film 6 (see FIG. 10).

  As a material of the transparent resin plate 16 having optical isotropy in each of the above-described modifications, for example, a resin having excellent transparency such as a polycarbonate-based resin, an acrylic-based resin, or a polystyrene-based resin is used. The thickness of the transparent resin plate 16 having optical isotropy is, for example, 0.3 to 5.0 mm. If the thickness is less than 0.3 mm, the stability and durability of pressing deteriorate, so that deformation such as dents easily occurs due to repeated input. Further, if it exceeds 5.0 mm, it becomes heavier than glass and is not effective as a portable device.

  On the other hand, a number of spacers 10 are formed between the movable electrode unit 3 and the fixed electrode unit 5 that are opposed to each other, and the spacers 10 are pressed by pressing the upper optical retardation film 4 with a finger or a pen. The movable electrode section 3 contacts the fixed electrode section 5 in an area where there is no input, and an input is performed.

  The spacer 10 in the figure is exaggerated for easy understanding, and it is actually difficult to visually recognize the spacer. As an actual example, the height of each spacer 10 is 1 to 15 μm, the outer diameter of the cylinder that is each spacer 10 is 30 to 100 μm, and the spacers 10 are arranged at a constant interval of 0.1 mm to 10 mm. ing.

  An upper polarizing plate 8 is disposed on the upper surface of the upper optical retardation film 4, and its absorption axis is disposed at an angle of about 45 ° with respect to the optical axis of the upper optical retardation film 4. Here, about 45 ° is for changing linearly polarized light into circularly polarized light or substantially circularly polarized light, and is allowed up to ± 3 °. By arranging in this manner, the amplitudes of the two orthogonal polarization components become equal, and the linearly polarized light that has passed through the upper optical retardation film 4 becomes circularly polarized light or substantially circularly polarized light.

  Here, the reason why the absorption axis of the upper polarizing plate 8 is allowed to be ± 3 ° with respect to 45 ° with respect to the optical axis of the upper optical retardation film 4 will be described.

  If the absorption axis of the upper polarizing plate 8 is not arranged so as to form an angle of exactly 45 ° with the optical axis of the upper optical retardation film 4, the linearly polarized light incident on the upper optical retardation film 4 It becomes elliptically polarized light without changing to circularly polarized light.

  Thereafter, the circularly polarized light returned by the reflection passes through the upper optical retardation film 4 again and is emitted as linearly polarized light from the upper surface of the upper optical retardation film 4, but the elliptically polarized light returned by the reflection is reflected by the upper optical retardation film. 4 emits as elliptically polarized light closer to linearly polarized light from the upper surface. In the case of perfect linearly polarized light, since it is orthogonal to the transmission axis (similar to a slit) of the upper polarizing plate 8 thereafter, it is not emitted from the upper surface of the upper polarizing plate 8, and as a result, reflected light can be suppressed. . On the other hand, when the light is not completely linearly polarized as described above, the emission of the component perpendicular to the transmission axis of the upper polarizing plate 8 can be stopped, but the component that matches the transmission axis of the upper polarizing plate 8 can be stopped. 8 from the upper surface. That is, extra reflection remains.

  However, if the absorption axis of the upper polarizing plate 8 is within ± 3 ° even if it is not exactly at an angle of 45 ° with respect to the optical axis of the upper optical retardation film 4, almost circular polarization (that is, substantially circular polarization) is obtained. The same is true, and the reflected light finally emitted from the upper surface of the upper polarizing plate 8 (the upper surface of the liquid crystal display device) can be ignored.

  Next, as a material of the upper polarizing plate 8, generally, polyvinyl alcohol is impregnated with a dichroic dye such as iodine or a dye and stretched, and a cellulose-based protective material such as triacetyl cellulose is formed on both front and rear surfaces. A flexible polarizing plate having a thickness of 200 μm and covered with a film is used. An example of such an upper polarizing plate 8 is “HEG1425DU manufactured by Nitto Denko”.

  Further, a low reflection treatment layer may be formed on the upper surface of the upper polarizing plate 8 by performing a low reflection treatment. Examples of the low reflection treatment method include a method of applying a low reflection material using a low refractive index resin such as a fluororesin or a silicon resin, forming a metal multilayer film, and attaching a low reflection film. Here, generally, about 4% of the total reflection of the touch input type liquid crystal display device is the reflection of the touch panel surface, and the processing of suppressing the reflection to less than 1% is called the low reflection processing. .

  In order to protect the upper polarizing plate 8 and the upper optical retardation film 4 from abrasion due to pressing by a finger or a pen, a hard coat processing layer made of an acrylic resin, a silicon resin, or a UV curable resin is provided on the upper polarizing plate 8. It may be formed.

  By arranging the transparent touch panel 1 and the upper polarizing plate 8 in such a configuration, it is possible to suppress reflected light due to light incident from the outside as described below.

  Incident light from the observer side passes through the upper polarizing plate 8 and becomes linearly polarized light. When this linearly polarized light passes through the upper optical retardation film 4 which gives a 1/4 wavelength phase delay to the incident light of the central wavelength whose optical axis is inclined by about 45 ° with respect to the absorption axis of the upper polarizing plate 8, the linearly polarized light becomes The polarization components are orthogonal to each other and divided into two polarization components having the same amplitude, and one of the polarization components causes a phase delay of 波長 wavelength. As a result, the light is changed from linearly polarized light to circularly polarized light or substantially circularly polarized light. Then, the circularly-polarized light or substantially circularly-polarized light reflected at the interface between the spatial layer 7 and the fixed electrode portion 5 having the largest difference in the refractive index at the interface passes through the upper optical retardation film 4 again. The light that has passed through the upper optical retardation film 4 changes from circularly or substantially circularly polarized light to linearly polarized light. At this time, the linearly polarized light changes by 90 ° with respect to the linearly polarized light that first passes through the upper polarizing plate 8. Since the light becomes linearly polarized light substantially perpendicular to the transmission axis of the upper polarizing plate 8, light does not pass. Therefore, reflected light is suppressed.

  The substantially circularly polarized light here is a state very close to circularly polarized light. When the optical axis of the upper optical retardation film 4 forms an angle of 45 ° with the absorption axis of the upper polarizing plate 8, the light becomes circularly polarized light, and otherwise, it becomes elliptically polarized light. In the above embodiment of the present invention, since the upper polarizing plate 8 and the upper optical retardation film 4 are arranged with a tolerance of ± 3 ° with respect to the angle, a case where the light is changed to “circularly polarized light or substantially circularly polarized light” is used here. “Substantially circularly polarized light” is elliptically polarized light within the allowable range of ± 3 °. The optical axis of the upper optical retardation film 4 is an axis parallel to a stretching direction of a film material of the upper optical retardation film 4 as a raw material.

  The absorption axis (or absorption axis) of the upper polarizing plate 8 is an axis parallel to the stretching direction of the film material. The light passing through the upper polarizing plate 8 is polarized and emitted from the upper polarizing plate 8 as linearly polarized light only in a direction orthogonal to the absorption axis.

  Note that an axis perpendicular to the absorption axis is called a transmission axis. In order for the upper polarizing plate 8 to transmit linearly polarized light, the transmission axis and the direction must match. Linearly polarized light whose directions do not match cannot pass through the upper polarizing plate 8.

  The linearly polarized light emitted from the liquid crystal display 2 is converted from the light from the backlight to linearly polarized light by the polarizer (in this case, the lower polarizer) as described above, and then passes through the liquid crystal display 2. For example, in the case of a normally white display mode, light is emitted so as to coincide with the transmission axis of the upper polarizing plate 8 below the threshold voltage, and not coincident with the transmission axis of the upper polarizing plate 8 above the threshold voltage. It is emitted. In the normally black display mode, on the contrary, when the threshold voltage is exceeded, the light is emitted so as to coincide with the transmission axis of the upper polarizer 8. Out.

  Similarly to the absorption axis of the upper polarizing plate 8, the absorption axis (or absorption axis) of the lower polarizing plate 9 is an axis parallel to the stretching direction of the film material. The light passing through the lower polarizing plate 9 is polarized and emitted from the lower polarizing plate 9 as linearly polarized light only in a direction orthogonal to the absorption axis.

  Further, in order to suppress coloring when the display screen of the liquid crystal display device is viewed from the observer side, between the upper optical retardation film 4 of the transparent touch panel 1 and the liquid crystal display 2 with respect to the incident light of the center wavelength, 1 /. A lower optical retardation film 6 for providing a phase delay of four wavelengths is arranged. More preferably, when the lower optical retardation film 6 is bonded to the entire upper surface of the liquid crystal display 2 via a transparent adhesive or the like, not only the coloring of the display screen can be suppressed but also the reflected light can be more effectively suppressed. .

  At this time, the optical axis of the upper optical retardation film 4 and the optical axis of the lower optical retardation film 6 are arranged at about 90 °. Here, about 90 ° is for changing circularly polarized light or substantially circularly polarized light after passing through the lower optical retardation film 6 to linearly polarized light by the upper optical retardation film 4, and is allowed to be ± 3 °. .

  Further, the lower optical retardation film 6 is arranged such that the optical axis of the lower optical retardation film 6 is about 45 ° with respect to the linearly polarized light emitted from the liquid crystal display 2 and desired to be emitted from the device surface. Here, about 45 ° is for changing linearly polarized light into circularly polarized light or substantially circularly polarized light, and is allowed up to ± 3 °. In the case of the configuration using the lower optical retardation film 6 having the fixed electrode portion 5 on the upper surface, the coloring of the display screen is suppressed and the optical screen is part of the transparent touch panel 1. Need not be added. Among the linearly polarized light emitted from the liquid crystal display 2, the linearly polarized light to be emitted from the surface of the device has an angle of 90 ° with the absorption axis of the upper polarizing plate 8.

  As a liquid crystal display system used for the liquid crystal display 2, there are a transmission type and a reflection type TN liquid crystal display type, a transmission type and a reflection type STN display type, and the like. The lower optical retardation film 6 may be disposed so that the angle formed by the optical axis of the lower optical retardation film 6 and the optical axis of the lower optical retardation film 6 with respect to the linear polarized light to be emitted from the device surface is approximately 45 °. .

  In the case of the transmission type and the reflection type STN liquid crystal display system, in addition to the liquid crystal cell 2a as a configuration of the liquid crystal display 2, generally, as shown in FIG. The phase difference plate 14 is arranged on the upper surface of the liquid crystal cell 2a.

  In the case of a general TN liquid crystal display, as shown in FIG. 8, light emitted from the backlight light guide plate 13 passes through the polarizing plate 9 and becomes linearly polarized light. When this linearly polarized light passes through the liquid crystal display 2 below the threshold voltage, it becomes a 90 ° twisted linearly polarized light. Further, the linearly polarized light that has passed through the lower optical retardation film 6 becomes circularly polarized light and returns to linearly polarized light again by the upper optical retardation film 4. At this time, since the angle of the optical axis of the two optical retardation films is about 90 °, the direction of the linearly polarized light is orthogonal to the absorption axis of the upper polarizing plate 8 in the normally white display mode. That is, it coincides with the transmission axis. Therefore, the linearly polarized light can pass through the polarizing plate 8 and reach the observer.

  In the touch input type liquid crystal display device having the above-described configuration, the member on which the fixed electrode portion (5) is directly formed and the liquid crystal display 2 or all the members between them are displayed on the display surface. It may be adhered outside with a double-sided adhesive tape, but more preferably, it is entirely adhered with a transparent pressure-sensitive adhesive layer or a transparent removable sheet. In addition, all members may be stuck by only one of the transparent pressure-sensitive adhesive layer and the transparent removable sheet, or may be bonded by a transparent removable sheet between the members bonded by the transparent pressure-sensitive adhesive layer. May be mixed.

  The transparent pressure-sensitive adhesive layer is formed by applying a general transparent pressure-sensitive adhesive. Examples of the adhesive include an acrylic resin such as an acrylic ester copolymer, a urethane resin, a silicone resin, and a rubber resin. The transparent removable sheet is formed by forming a transparent polymer adhesive into a gel sheet. Examples of the polymer adhesive include urethane, acrylic, and natural polymer materials. With the transparent pressure-sensitive adhesive layer or the transparent removable sheet, the air layer between the member on which the fixed electrode portion (5) is directly formed and the liquid crystal display 2 can be eliminated. Has a refractive index higher than that of air, and constitutes a lower optical retardation film 6, a glass substrate 11 having optical isotropy, an optical isotropic film 12, a transparent resin plate 16 having optical isotropy, and the liquid crystal display 2. Since it is close to the refractive index of members such as glass plates, it suppresses the reflection of light at the interface between the transparent adhesive layer and the transparent removable sheet and these members, and finally the air layer, such as when double-sided adhesive tape is used The transmittance is higher than that of the structure having. Further, since the refractive index of the transparent pressure-sensitive adhesive layer or the transparent removable sheet is close to the refractive index of each member described above, the refraction of light at the interface between the transparent pressure-sensitive adhesive layer or the transparent removable sheet and each member is suppressed, and the screen is screened. There is no shadow on the display.

  In addition, the members adhered by the transparent re-peelable sheet are strong against the separating force acting in the vertical direction and the displacing force in the horizontal direction, and are easily separated when the members are separated from each other so as to be flipped from the ends. Has features. Therefore, there is no fear of peeling in a normal use state after mounting, and it can be easily peeled at the time of maintenance or the like. Needless to say, the adhesive strength of the transparent re-peelable sheet does not decrease even after repeated detachment. Also, when a urethane-based polymer adhesive is used, the transparent re-peelable sheet is a material having both water absorbency and air absorptivity. The release sheet absorbs at room temperature and can ultimately give a bubble-free product without special treatment. The special treatment is, for example, a treatment in which a roll is moved while applying pressure from the end of the surface of the transparent touch panel 1 to expel bubbles. Such a special treatment cannot be applied to the case of the transparent touch panel 1 using the glass substrate 11 having optical isotropy, and the above-described bubble absorption at room temperature becomes extremely useful.

  Next, a method for manufacturing a touch input type liquid crystal display device will be described in detail.

(Upper optical retardation film 4 of touch panel 1)
The upper optical retardation film 4 can have a predetermined retardation by uniaxially stretching the unstretched film material. In this embodiment, the refractive index in the x direction, which is the optical axis direction of the film material, the refractive index in the y direction perpendicular to the x direction, and the thickness direction of the film material, ie, the z direction perpendicular to the x direction and the y direction. By controlling the refractive index, a roll-shaped film material having a phase difference of 1/4 wavelength in visible light of about 550 nm as an example, which is the wavelength having the highest visibility, is obtained. Used for film 4. The case where the lower optical retardation film 6 has a phase difference is the same as that of the upper optical retardation film 4.

(Movable electrode part 3 of touch panel 1)
A part of the transparent conductive film of the movable electrode part 3 is formed on the roll-shaped film material for the upper optical retardation film 4, and the method includes sputtering, vapor deposition, or CVD. Before forming a transparent conductive film, it is necessary to perform as high a temperature treatment as possible to remove the residual solvent in the film material. This is because the presence of the residual solvent makes it impossible to form a stable transparent conductive film. After removing the residual solvent, the transparent conductive film is formed. In order to make the transparent conductive film more stable and have high strength, it is necessary to form the film at a high temperature of 150 ° C. or higher. Therefore, in a film material having a heat deformation temperature of less than 150 ° C., heat such as 150 ° C. or more causes deterioration such as deformation and distortion, and a phase difference of 波長 wavelength cannot be maintained. On the other hand, if the heat treatment is performed at a temperature lower than 150 ° C., the removal of the residual solvent becomes insufficient, and a stable high-strength transparent conductive film cannot be obtained. Therefore, the film material for forming the transparent conductive film must be a film material having a heat deformation temperature of 150 ° C. or higher because a high temperature treatment of 150 ° C. or higher is performed to remove the residual solvent in the film material.

  Since the film material with a transparent conductive film for the upper optical retardation film 4 thus produced is usually in the form of a roll as described above, it is cut into a predetermined size for forming a circuit, and Make a film material sheet. However, one film material sheet may be one touch panel 1, but is not limited thereto, and may be an arbitrary number of touch panels 1.

  The cut film material sheet is subjected to a heat treatment as needed to minimize dimensional errors during circuit formation. The heat treatment is desirably performed at 100 ° C. or higher and lower than 130 ° C. for about 1 hour. After that, a circuit for a lead wire or the like which is the remaining part of the movable electrode unit 3 is formed. The circuit forming method includes screen printing, offset printing, a roll coater, and a dispenser. As the ink used for forming the circuit, an ink obtained by dispersing conductive fine metal particles in a binder made of a thermosetting resin is used, and the viscosity is adjusted by adding a solvent to improve printability. Silver, nickel, copper, gold, or the like is used as the metal fine particles used in the conductive ink. High temperature drying is performed to cure the binder and remove the solvent. The drying temperature is 100 ° C. or more and less than 150 ° C. for 30 to 60 minutes. Adjust the drying conditions appropriately according to the ink used. It goes without saying that a film material whose phase difference of 1/4 wavelength does not change by heat treatment at the time of circuit formation is selected.

  When circuits are formed on a single film material sheet in a multi-pattern (that is, providing several touch panels), a large number of circuit-forming films can be produced in a short time, which is efficient.

  In cutting the roll film and forming the circuit, it is necessary to consider the direction of the optical axis of the upper optical retardation film 4. This is because there are various types of liquid crystal display systems such as TN and STN systems, and the angle between the linearly polarized light that is twisted out of the liquid crystal display and the side of the display screen is different depending on the system. Naturally, the optical axis of the upper optical phase difference film 4 arranged so as to form a certain angle with the linearly polarized light forms a different angle with respect to the side of the upper optical phase difference film 4 for each liquid crystal display. However, the side of the display screen is not necessarily 45 ° from the linearly polarized light that is twisted out of the liquid crystal display 2 and the side of the display screen. In this case, the optical axis of the upper optical retardation film 4 is also relative to the side of the upper optical retardation film 4. Although not parallel, the optical axis direction and the stretching direction of the roll-shaped upper optical retardation film 4 are parallel. Therefore, the following is performed to make the optical axis of the upper optical retardation film 4 arranged as a member of the touch panel 1 have a predetermined angle with respect to the side of the upper optical retardation film 4. One is a method of giving an angle to the cutting for forming the circuit. For example, if the optical axis of the upper optical retardation film 4 of the transparent touch panel 1 must be at an angle of 30 ° with respect to the side of the upper optical retardation film 4, cutting is also performed when cutting for forming a circuit. The edge of the subsequent sheet material film sheet is cut into a rectangular shape having a predetermined size at an angle of 30 ° with respect to the edge of the roll-shaped film material, and then the circuit is printed and formed in a normal pattern. Alternatively, it is a method of giving an angle to the pattern layout. For example, when a circuit is formed by printing, the roll-shaped film material can be cut perpendicularly to the stretching direction by forming the pattern layout of the plate for forming the circuit print at an angle of 30 ° as a whole (of course, in the latter case). In this case, since the sheet material sheet and the layout of the pattern have an angle, when obtaining one film material sheet to be arranged on the touch panel 1 to be described later, cutting is performed at an angle after circuit formation. There is a need.)

  Further, in forming a circuit, it is necessary to prevent unnecessary contact (that is, unnecessary overlapping) between the transparent conductive film and the lead wire. Usually, the transparent conductive film is subjected to a patterning process into a predetermined shape before forming the circuit. Keep it. Examples of the patterning method include a printing resist method, a photolithography method, and a method of directly pattern-printing a transparent conductive film.

(Fixed electrode part 5 of touch panel 1)
On the other hand, in the formation of the fixed electrode section 5, a circuit is formed in substantially the same process as that of the movable electrode section 3. When the optically isotropic film 12 or the glass substrate 11 having optically isotropic property is disposed between the lower optical retardation film 6 and the fixed electrode part 5, the optics or the like on which the fixed electrode part 5 is directly formed Since the isotropic film 12 or the glass substrate 11 having optical isotropy does not have an optical axis, it is not necessary to form an angle when cutting or forming a circuit. When the fixed electrode portion 5 is directly provided on the lower optical retardation film 6, it is exactly the same as the case where the movable electrode portion 3 is provided on the upper optical retardation film 4. The same ink material as the ink used in the movable electrode unit 3 can be used. High temperature drying is performed to cure the binder and remove the solvent. The drying temperature is 100 ° C. or more and less than 150 ° C. for 30 to 60 minutes (when the fixed electrode portion 5 is directly provided on the lower optical retardation film 6, the phase difference of 波長 wavelength is not changed by the heat treatment at the time of forming the circuit. It goes without saying that an optical retardation film is selected).

(Ensuring insulation of touch panel 1)
After the circuit formation, the movable side sheet (upper optical retardation film 4) on which the movable electrode section 3 is directly formed and the fixed side sheet (optically isotropic film 12, or optical section) on which the fixed electrode section 5 is directly formed Before combining the anisotropic glass substrate 11 and the lower optical retardation film 6) into the touch panel 1, in order to prevent lead wires and electrodes from being in contact with each other between upper and lower members to cause insulation failure, furthermore, In order to prevent metal oxidation of the circuit, an insulating layer is formed on at least one of the movable electrode side and the fixed electrode side. As a method for forming the insulating layer, there are a printing resist method, screen printing, offset printing, a roll coater, a dispenser, and the like as in the circuit formation. As the material, a thermosetting resin or the like having an insulating property is used.

  Further, in order to secure insulation between the transparent conductive film of the movable electrode portion 3 of the touch panel 1 and the transparent conductive film of the fixed electrode portion 5, the upper surface of the touch panel 1 is pushed or released with a pen or a finger. In order to smoothly turn ON and OFF the conduction in the event of a break, a large number of spacers 10 are formed between the transparent conductive film of the movable electrode portion 3 and the transparent conductive film of the fixed electrode portion 5. The formation surface of the spacer 10 is formed on the electrode surface of at least one of the transparent conductive film on the fixed electrode portion side and the movable electrode portion side. As a method of forming the spacer 10, there is a screen printing, an offset printing, a dispenser method, or the like, which is directly formed into an arbitrary shape of the spacer 10. In addition, there is a photolithography method in which a film formed over the entire surface is patterned into a spacer shape, a printing resist method, or the like. Although the shape of the spacer is not particularly limited, it is desirable to arrange the spacers at the same shape and at regular intervals in order to perform a uniform input in order to eliminate an uninputable portion. When the spacers are formed in a dot shape, it is desirable that the spacer diameter is small and the height is low. As an example, an array pattern having a spacer diameter of 30 to 100 μm, a height of 1 to 15 μm, a spacer pitch of 0.1 to 10 mm, and an intersection pattern of a plurality of lines orthogonal to each other vertically and horizontally is formed on the side of the touch panel 1. On the other hand, it can be formed by being rotated by 0 to 90 ° as a whole.

(Cut for one electrode sheet)
A movable side sheet (upper optical retardation film 4) directly formed with a movable electrode portion 3 and a fixed side sheet (optically isotropic film 12 or an optically isotropic film) directly formed with a fixed electrode portion 5 on which a circuit is formed. The glass substrate 11 having the property and the lower optical retardation film 6) are further cut into a predetermined size in the case of a multi-pattern. When the fixed side sheet is a film, the sheet is cut by a Thomson mold, a mold, a cutting plotter, or the like. In particular, when cutting the glass substrate 11 having optical isotropy, it is desirable to insert a blade from the surface opposite to the conductive film because the conductive film surface is hard and difficult to insert a blade. By doing so, the glass cross section is cut neatly, and a decrease in strength is prevented.

(Lamination of upper and lower movable side sheets and fixed side sheets)
The movable side sheet (upper optical retardation film 6) directly formed with the movable electrode section 3 and the fixed side sheet (optically isotropic film 12 or glass substrate having optical isotropic property) directly formed with the fixed electrode section 5 11, the lower optical retardation film 6) is bonded with an adhesive or a double-sided tape 19 to form a space layer 7 between the electrodes. In the case of forming a circuit with a multi-pattern, if the adhesive or the double-sided tape 19 is formed in advance before cutting the upper and lower movable side and fixed side sheets, the process time can be further shortened and it is more efficient. An adhesive material or a double-sided tape 19 is formed around the movable electrode portion 3 or the fixed electrode portion 5 and bonded so that the two electrode portions 3 and 5 are opposed to each other, and are pressure-bonded by applying external pressure. The adhesive material in place of the double-sided tape 19 is formed by screen printing or the like, and the double-sided tape used is punched in a frame shape in advance. These are formed outside the see-through area of the touch panel 1. When the adhesive or the double-sided tape enters the see-through area, the image on the edge of the touch panel becomes blurred and difficult to see. Examples of the adhesive include acrylic, epoxy, urethane, and copolymers thereof, and as the double-sided tape, for example, Nitto Denko 532 or the like is preferably used.

(Connector)
An external take-out unit (connector) 40 for detecting a contact position (that is, an input position) of the upper and lower electrode units 3 and 5 of the touch panel 1 is provided. As a method, there is a method of extracting an electrode from each of the electrode portions 3 and 5, a method of extracting an electrode from one of the electrode portions 3 and 5, and the like. It is preferable that an electrode lead portion is provided on the touch panel 1 in advance, and the electrode is pressed against the connector (40) at 120 ° C. or more and less than 170 ° C. via an anisotropic conductive adhesive.

  The above is the method of manufacturing the touch panel 1. Next, a method of manufacturing a touch input type liquid crystal display device by combining the touch panel 1 and the liquid crystal display 2 will be described.

(Lamination of upper polarizing plate 8)
The upper polarizing plate 8 is attached to the upper surface of the upper optical retardation film 4 of the touch panel 1 manufactured as described above. When a transparent film is further disposed on the upper polarizing plate 8, the upper polarizing plate 8 and the transparent film may be separately bonded to the upper optical retardation film 4 on the touch panel 1, or the upper polarizing plate may be 8 and a transparent film may be cut into a predetermined size and bonded on the touch panel 1. These films are adhered to the entire surface via a transparent adhesive. Although the sizes of the upper polarizing plate 8 and the transparent film are not particularly limited, they are usually adhered so as to be the same as the outer shape of the touch panel or about 0.1 to 1 mm inside each side of the outer shape of the touch panel. This is because, when the outer polarizer 8 and the transparent film are outside the outer shape of the touch panel, the upper polarizer 8 and the transparent film are easily peeled off when an external force is applied. However, the size is not limited to this.

  After bonding the upper polarizing plate 8, pressure degassing treatment is performed at 40 to 80 ° C and 4 to 9 kg / cm 2 for 10 to 120 minutes. When the upper polarizer 8 is pasted on the touch panel 1, air bubbles are mixed between the upper optical retardation film 4 and the upper polarizer 8 or between the upper polarizer 8 and the transparent film. Thus, the bubbles can be dispersed, and the adhesion between the films can be improved.

(Lamination of the lower optical retardation film 6 without directly forming the fixed electrode portion 5)
When an optically isotropic film 12 or a glass substrate 11 having optical isotropy is used as a fixed side sheet for directly forming the fixed electrode portion 5, a lower optical phase difference between the fixed side sheet and the liquid crystal display 2. The film 6 is arranged. The lower optical retardation film 6 is entirely formed on a member on the liquid crystal display 2 side (a glass surface of the liquid crystal display unit, or a polarizing plate or another optical retardation film disposed on the liquid crystal display unit) via an adhesive. It is desirable to stick them together. The lower optical retardation film 6 may be pasted to a polarizing plate or another optical retardation film disposed on the liquid crystal display portion in advance and then to the liquid crystal display portion, or separately to the liquid crystal display portion. May be combined.

  After bonding, it is desirable to perform pressure defoaming treatment. A pressurized defoaming treatment is performed at 40 to 80 ° C and 4 to 9 kg / cm 2 for 10 to 120 minutes. By performing this operation, the bubbles can be dispersed, and the adhesion between the films can be improved.

(Lamination of the fixed side sheet to the liquid crystal display side)
The fixed sheet directly forming the fixed electrode section 5 is adhered to a member on the liquid crystal display side together with the members arranged on the fixed sheet directly forming the fixed electrode section 5 with a double-sided tape or the like. It may be directly attached to a member on the liquid crystal display side (the lower optical retardation film 6 may be the uppermost layer as described above), or a housing may be provided between the member on the liquid crystal display side and the housing. May be pasted on. Alternatively, it may be attached to the entire surface with a transparent pressure-sensitive adhesive layer or a transparent removable sheet.

  Next, a touch input type liquid crystal display device and a method of manufacturing the same according to fourth to sixth embodiments of the present invention will be described.

  This fourth embodiment is made for the following purpose. That is, in the liquid crystal display devices according to the first to third embodiments, the following problems may occur.

  First, when the durability of the surface of the upper polarizing plate 8 is not good, the surface of the upper polarizing plate 8 may be damaged due to pen input or the like, and the utility may be poor. Further, when moisture is absorbed from the surface of the upper polarizing plate 8, the upper polarizing plate 8 is liable to contract, expand or be distorted, and the upper optical retardation film 4 bonded to the upper polarizing plate 8 follows the retardation value. Is partially changed, and when viewed from the observer side, color unevenness is conspicuous, and the antireflection function may be impaired.

  Therefore, an object of the fourth to sixth embodiments of the present invention is to solve the above-mentioned disadvantages, and to solve the above-mentioned problems, to provide a transparent touch panel 1 having excellent surface durability and preventing moisture absorption on the upper polarizing plate 8 and a touch input using the same. It is an object of the present invention to provide a liquid crystal display device of the type.

  Hereinafter, fourth to sixth embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 11 is a sectional view showing a touch input type liquid crystal display device (transmission type TN) according to the fourth embodiment.

  FIG. 12 is a sectional view showing a touch input type liquid crystal display device (transmission type STN) according to the fifth embodiment.

  FIG. 13 is a sectional view showing a touch input type liquid crystal display device (reflection type STN) according to the sixth embodiment.

  FIG. 14 is an explanatory diagram in the transmission axis direction and the optical axis direction in the touch input type liquid crystal display device (TN) according to the embodiment of the present invention.

  FIG. 15 is a cross-sectional view showing a touch input type liquid crystal display device (transmissive TN) according to a modification of the fourth embodiment.

  FIG. 16 is a sectional view showing a touch input type liquid crystal display device (reflection type STN) according to a modification of the sixth embodiment.

  In the figure, 22 is a transparent film, 23 is a low reflection treatment layer, 24 is an antifouling treatment layer, and 25 is a hard coat treatment layer.

  As the base material on which the fixed electrode portion 5 is directly formed, the lower optical retardation film 6 (fourth embodiment; see FIG. 11) or the glass substrate 11 having optical isotropy (fifth embodiment; see FIG. 12) Alternatively, an optically isotropic film 12 (sixth embodiment; see FIG. 13) is used. These base materials are also subjected to high-temperature treatment when forming the fixed electrode portion 5 and forming the circuit similarly to the upper optical retardation film 4.

  In the fourth embodiment, when priority is given to pressing stability and durability similar to the glass substrate 11 having optical isotropy over thinning, the optical isotropy is provided between the transparent touch panel 1 and the liquid crystal display 2. It is preferable to arrange a transparent resin plate 16 having a property (see FIG. 15). In the sixth embodiment, when priority is given to pressing stability and durability similar to the glass substrate 11 having optical isotropy over thinning, the optical isotropic film 12 and the lower optical retardation film 6 need It is preferable to dispose a transparent resin plate 16 having optical isotropy between them (see FIG. 16). As a material of the transparent resin plate 16 having optical isotropy, for example, a resin having excellent transparency such as a polycarbonate-based resin, an acrylic-based resin, or a polystyrene-based resin is used. Its thickness is 0.3-5.0 mm. If the thickness is less than 0.3 mm, the stability and durability of pressing deteriorate, so that deformation such as dents easily occurs due to repeated input. Further, if it exceeds 5.0 mm, it becomes heavier than glass and is not effective as a portable device.

  The function of the transparent film 22 is excellent in transparency, low in moisture permeability, and excellent in dimensional stability. As a material of the transparent film 22, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyether ketone, polyolefin, or the like is used. Its thickness is 100 μm or less, preferably 80 μm.

  Further, a low-reflection processing layer 23 which has been subjected to low-reflection processing may be applied to the upper surface of the transparent film 22 bonded to the upper surface of the upper polarizing plate 8. The low-reflection treatment method for forming the low-reflection treatment layer 23 includes applying a low-reflection material using a low-refractive-index resin such as a fluororesin or a silicone resin, forming a multi-layered metal film by vapor deposition, or the like. There is a method of attaching a reflective film, sandblasting, embossing, matte coating, or processing the surface into a satin finish by etching or the like. Further, these low reflection processing methods may be combined.

  Further, an antifouling treatment layer 24 which has been subjected to antifouling treatment may be applied to the upper surface of the transparent film 22 bonded to the upper surface of the upper polarizing plate 8.

  Further, in order to protect the transparent film 22 bonded to the upper surface of the upper polarizing plate 8 from abrasion due to pressing by a finger or a pen or the like, a hard coat treatment layer 25 which has been subjected to a hard coat treatment may be applied. For example, the hard coat processing layer 25 made of an acrylic resin, a silicon resin, a UV curing resin, or the like is formed.

  Further, the low reflection treatment layer 23, the antifouling treatment layer 24, and the hard coat treatment layer 25 may be formed by combining some of them.

  By arranging the transparent touch panel 1 and the upper polarizing plate 8 in such a configuration, it is possible to suppress reflected light due to light incident from the outside as described below.

  Incident light transmitted through the transparent film 22 from the observer side passes through the polarizing plate 8 and becomes linearly polarized light. Other functions and effects are the same as those of the previous embodiment.

  Although the present invention has been fully described in connection with preferred embodiments with reference to the accompanying drawings, various changes and modifications will be apparent to those skilled in the art. It is to be understood that such changes and modifications are included therein unless they depart from the scope of the invention as set forth in the appended claims.

FIG. 1 is a sectional view showing a touch-input type liquid crystal display device (transmissive TN (Twisted Nematic)) according to the first embodiment of the present invention. FIG. 2 is an exploded perspective view of the liquid crystal display device of FIG. 1. FIG. 2 is a schematic sectional view of the liquid crystal display device of FIG. FIG. 2 is an explanatory diagram for describing a state in which reflection of external light is suppressed in the liquid crystal display device of FIG. 1. It is explanatory drawing of a backlight light guide plate. It is sectional drawing which shows the liquid crystal display device (transmission type STN (Super Twisted Nematic)) of the touch input system which concerns on 2nd Embodiment. It is sectional drawing which shows the liquid crystal display device (reflection type STN) of the touch input type which concerns on 3rd Embodiment. It is explanatory drawing of the transmission axis direction and the optical axis direction in the touch input type liquid crystal display device (TN) which concerns on the said embodiment of this invention. It is sectional drawing which shows the liquid crystal display device (transmission type TN) of the touch input type based on the modification of 1st Embodiment. It is sectional drawing which shows the liquid crystal display device (reflection type STN) of the touch input type which concerns on the modification of 3rd Embodiment. It is sectional drawing which shows the liquid crystal display device (transmission type TN) of the touch input type based on 4th Embodiment of this invention. It is sectional drawing which shows the liquid crystal display device (transmission type STN) of the touch input type which concerns on 5th Embodiment of this invention. It is sectional drawing which shows the liquid crystal display device (reflection type STN) of a touch input method based on 6th Embodiment of this invention. FIG. 3 is an explanatory diagram of a transmission axis direction and an optical axis direction in the touch input type liquid crystal display device (TN) according to the embodiment. It is sectional drawing which shows the liquid crystal display device (transmission type TN) of the touch input type which concerns on the modification of 4th Embodiment. It is sectional drawing which shows the liquid crystal display device (reflection type STN) of the touch input type which concerns on the modification of 6th Embodiment. It is sectional drawing which shows an example of the liquid crystal display apparatus provided with the conventional general transparent touch panel. It is sectional drawing which shows another example of the liquid crystal display provided with the conventional general transparent touch panel. FIG. 18 is an explanatory diagram for explaining a state when the portable personal computer having the conventional liquid crystal display device of FIG. 17 is used in a room such as a fluorescent lamp. FIG. 19 is an explanatory diagram illustrating a state when the portable terminal having the conventional liquid crystal display device of FIG. 18 is used outdoors.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 The said transparent touch panel 2 Liquid crystal display 3 Movable electrode part 4 Upper optical retardation film 5 Fixed electrode part 6 Lower optical retardation film 7 Space layer 8 Upper polarizing plate 9 Lower polarizing plate 10 Spacer 11 Glass substrate 12 Optical isotropic Film 13 Backlight light guide plate 13a Linear light source 13b Diffusion sheet 13c Light guide plate 13d Light reflector 13e Light scattering layer 14 Optical compensation retardation plate 15 Reflector 16 Transparent resin plate 19 Double-sided tape 20 Movable sheet 21 Fixed side sheet 22 Transparent film 23 Low reflection treatment layer 24 Antifouling treatment layer 25 Hard coat treatment layer 40 Connector 500 Portable terminal 501 Pen 502 Portable personal computer 503 Pen 504 Fluorescent lamp

Claims (4)

In a touch input type liquid crystal display device having a liquid crystal display below the transparent touch panel,
An upper optical retardation film having a phase delay of 1/4 wavelength with respect to the incident light having the center wavelength in the visible region and having a movable electrode portion on the lower surface; and a 1/4 wavelength with respect to the incident light having the center wavelength in the visible region. An upper polarizing plate is disposed on the upper surface of the transparent touch panel in which a lower optical retardation film having a fixed electrode portion on the upper surface and a lower electrode is provided via a spatial layer, and a lower surface on the lower surface of the liquid crystal display. A polarizing plate is disposed, an angle between the optical axis of the upper optical retardation film and the absorption axis of the upper polarizing plate is about 45 °, and the light emitted from the optical axis of the lower optical retardation film and the liquid crystal display. The angle between the linearly polarized light and the linearly polarized light to be emitted from the device surface is about 45 °, and the optical axis of the upper optical retardation film and the optical axis of the lower optical retardation film are different from each other. Degrees There are about 90 °, an angle formed 90 ° with the absorption axis of the linear polarized light and the upper polarizer is desired to exit from among the device surface of the linearly polarized light emitted from the liquid crystal display,
An optically isotropic film is provided between the fixed electrode portion and the lower optical retardation film, and the fixed electrode portion is directly formed on the optically isotropic film, and the upper optical retardation film and A touch input type liquid crystal display device in which the heat distortion temperature of the optically isotropic film is 150 ° C. or higher. The touch input type liquid crystal display device according to claim 1, wherein the upper optical retardation film and the optically isotropic film have a heat deformation temperature of 170 ° C or higher. The touch-input type liquid crystal according to claim 1, wherein a transparent resin plate having optical isotropy is arranged between the optical isotropic film and the lower optical retardation film. Display device. The touch input type liquid crystal display device according to claim 1, wherein a thickness of the upper optical retardation film is 50 μm or more and 150 μm or less.

Images