JPH07248488A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve reflection preventing performance, to make a displayed picture easy to be viewed and to enhance display quality such is contrast. CONSTITUTION:A liquid crystal display device is provided with a transparent substrate 67 arranged on the display surface side of a liquid crystal display substrate 62 and a tablet board 66 arranged on the back surface side of the substrate 62. The locus of a stylus 83 tracing the surface of the substrate 67 is detected by the board 66. Based on the detection, the locus of the stylus 83 is displayed on the display surface of the substrate 62. Then, an intermediate layer 100 consisting of a material whose refractive index is approximate to those of the substrates 67 and 62 is provided between the substrate 67 traced by the stylus 83 and the substrate 62.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device,
In particular, the present invention relates to a liquid crystal display device commonly referred to as a pen input type, which displays a locus of the stylus by tracing the display surface with the stylus.

[0002]

2. Description of the Related Art The basic structure of this type of liquid crystal display device is
It has a liquid crystal display substrate and a tablet board arranged on the back surface side of the liquid crystal display substrate, and the tablet board detects the locus of the stylus by tracing the display surface side of the liquid crystal display substrate with a stylus. Based on this detection, the locus of the stylus is displayed on the display surface of the liquid crystal display substrate.

Since the above-mentioned liquid crystal display substrate has a structure in which, for example, two glass substrates are opposed to each other with a liquid crystal interposed therebetween, when the surface of the liquid crystal display substrate is directly traced by the stylus, the additional The liquid crystal unevenness caused by the deflection of the glass substrate due to the pressure appears on the display surface as it is, and the display quality is deteriorated.

Therefore, it is usual that another glass substrate for tracing the stylus is arranged with a certain gap on the display surface side of the liquid crystal display substrate.

FIG. 18 is a sectional view schematically showing the structure of a conventional pen input type liquid crystal display device, showing an example of a semi-transmissive type liquid crystal display device.

In the drawing, 11 is an upper electrode substrate, 12 is a lower electrode substrate, 15 is an upper polarizing plate, 16 is a lower polarizing plate, 17 is a semitransparent film, 40 is a birefringent member, 50 is a liquid crystal layer, and 52 is a liquid crystal layer. Sealing agent, 60 is a liquid crystal cell, 62 is a liquid crystal display substrate, 63 is a light guide, 66 is a tablet board, 67 is a transparent substrate, 6
7A is a non-glare treated surface, 67B is a soft sheet, 67
C is a glass plate, 83 is a stylus, 101A is an optical path (external light), 101B is an optical path (display image light, light source is a backlight).

As shown in the figure, this liquid crystal display device has a semi-transparent film 17, and the image formed in the liquid crystal cell 60 is in the transmissive mode when the backlight (not shown) is on, and the image of the backlight is displayed. In the off state, each is displayed in reflection mode.

As a disclosure of the prior art relating to this type of liquid crystal display device, for example, Japanese Patent Application Laid-Open No. 3412/1992 is available.
No. 82 publication can be mentioned.

[0009]

In the above conventional liquid crystal display device, when the displayed image is viewed in the reflection mode,
External light 101A entering the liquid crystal display device from the outside
Is the point P on the inside of the glass plate 67C and the outside Q of the upper polarizing plate 15.
There is a problem in that the display image is very difficult to see due to the reflected light at each point.

Further, in the above-mentioned conventional liquid crystal display device, when the displayed image is viewed in the transmission mode, the display image light 101B using the backlight as a light source is the inside R of the glass plate 67C.
However, there is a problem in that the display image becomes very difficult to see because the transmittance is reduced by reflecting the light inward at the point S and the point S on the outside of the upper polarizing plate 15, so that the brightness is reduced. Of course, even in this case, there is a problem in that the difficulty of seeing due to the reflection of the extraneous light is added to the decrease in the luminance, and the display image becomes more difficult to see.

The present invention has been made in view of the above circumstances, and its object is to make the displayed image clearer than before and to be disturbed by the reflection of extraneous light in both reflection mode and transmission mode. Another object is to provide a liquid crystal display device in which a display image is very easy to see.

[0012]

In order to achieve the above-mentioned object, the present invention basically has a liquid crystal display substrate 62 and a display surface of the liquid crystal display substrate as shown in FIG. A transparent substrate 67 disposed on the side of the liquid crystal display substrate, and a tablet board 66 disposed on the back side of the liquid crystal display substrate. The tablet board 66 detects the locus of the stylus 83 tracing the surface of the transparent substrate 67. In a liquid crystal display device configured to display the locus of the stylus on the display surface of the liquid crystal display substrate 62 based on detection, a liquid crystal display substrate 62 and the transparent substrate 67 traced by the stylus 83 are arranged between the transparent substrate 67 and the liquid crystal display substrate 62. An intermediate layer 100 made of a substance having a refractive index similar to those of the substrates 67 and 62 is provided.

Further, according to the present invention, the liquid crystal display substrate 62 and the transparent substrate 67 arranged on the display surface side of the liquid crystal display substrate.
And a tablet board 66 disposed on the back surface side of the liquid crystal display substrate, the tablet board 66 detects the locus of the stylus 83 tracing the surface of the transparent substrate 67, and based on this detection, the liquid crystal display substrate In a liquid crystal display device configured to display the locus of the stylus 83 on the display surface 62, at least a non-glare surface 67A is formed on the surface of the transparent substrate 67 traced by the stylus 83, and traced by the stylus. Between the transparent substrate 67 and the liquid crystal display substrate 62, an intermediate layer 100 made of a substance having a refractive index similar to those of the substrates 67 and 62 is provided.

Furthermore, the present invention is characterized in that the intermediate layer 100 is formed of a curable resin.

Further, according to the present invention, the intermediate layer 1
00 is optically in close contact with the transparent substrate 67 and the liquid crystal display substrate 62.

[0016]

In FIG. 1, 11 is an upper electrode substrate, 12 is a lower electrode substrate, 15 is an upper polarizing plate, 16 is a lower polarizing plate, 17 is a semi-transparent film, 40 is a birefringent member, 50 is a liquid crystal layer, and 52 is a liquid crystal layer. Sealing agent, 60 liquid crystal cell, 62 liquid crystal display substrate, 63 light guide, 66 tablet board, 67 transparent substrate, 67A
Is a non-glare treated surface, 67B is a soft sheet, 67C is a glass plate, 83 is a stylus, 100 is an intermediate layer, 101
A is an optical path (external light), 101B is an optical path (display image light, light source is a backlight).

Similar to the description with reference to FIG. 18, the liquid crystal display device has the semi-transparent film 17, and the image formed in the liquid crystal cell 60 is in the transmissive mode when the backlight (not shown) is on, Further, when the backlight is off, the display is performed in the reflection mode.

According to the above-mentioned structure, the external light 101A has the transparent layer 67 and the liquid crystal display substrate 6 due to the presence of the intermediate layer 100.
Since the liquid crystal display substrate 62 reaches the liquid crystal display substrate 62 without being reflected at the boundary of 2, the reflection by the external light 101A is only the diffuse reflection of the non-glare treatment layer 67A of the transparent substrate 67. In addition, the display image light 101B that uses a backlight as a light source also receives the intermediate layer 1
The presence of 00 allows light to be transmitted to the outside without being reflected at the boundary between the transparent substrate 67 and the liquid crystal display substrate 62, so that the transmission is also improved, the brightness is improved, and the contrast is enhanced to make the displayed image very easy to see.

The above-mentioned intermediate layer 100 is formed by injecting a curable resin between the transparent substrate 67 and the liquid crystal display substrate 62, or is formed by a thin plate or film of a curable resin coated with an adhesive on both sides, and is formed between them. By arranging them in optical contact with each other, there is no air layer at each boundary,
The reflection of light at the boundary is prevented.

The so-called non-glare layer 67A
Not only makes the writing feeling with the stylus good, but also serves to obscure the outline of extraneous light by diffuse reflection so as not to disturb the display image.

The soft sheet 67B which constitutes the transparent substrate 67 relieves the pressing force of the stylus, reduces the influence of damage to the liquid crystal element, and at the same time functions to prevent scattering even when the glass plate is broken. Ensure safety.

[0022]

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

FIG. 2 is a developed perspective view for explaining the overall structure of an embodiment of the liquid crystal display device according to the present invention, in which 62 is a liquid crystal display substrate, 62A is a printed circuit board, 62B is a liquid crystal display drive circuit, and 63 is a conductor. An optical body, 63A is a cold cathode tube, 64 is a cold cathode tube cover, 65 is a support frame, 66 is a tablet board, 67 is a transparent substrate, 68 is a metal frame, 69 is a spacer, and 100 is an intermediate layer.

In the figure, a printed circuit board 62A having a U-shape is arranged in the same plane as the liquid crystal display circuit board 62 around the liquid crystal display circuit board 62 (three sides in this figure).

A liquid crystal display drive circuit 62B is arranged at the boundary between the liquid crystal display board 62 and the printed board 62A. The liquid crystal display drive circuit 62B has a structure in which a semiconductor device is mounted on a flexible substrate, for example, and the electrodes formed on the flexible substrate are connected to the respective electrodes of the liquid crystal display substrate 62 and the printed circuit board 62A. ing.

The light guide 6 is provided on the back surface of the liquid crystal display substrate 62.
3 are arranged. This light guide 63 is used for the liquid crystal display substrate 6.
2 has a function of irradiating the back surface with light. That is, a light source (backlight) including a cold cathode tube 63A is arranged on one end surface of the light guide 63, and light from the cold cathode tube 63A enters the light guide 63 through the one end surface. Main surface of the light guide 63 (surface facing the liquid crystal display substrate 62)
It is supposed to be diffusely reflected from.

For this reason, a diffused reflection film is formed on the one end surface of the light guide 63 and the other surface except the main surface, and all the light from the cold cathode tubes 63A is guided to the light guide 63 side. A cold cathode ray tube cover 64 for introduction into A cylindrical reflector may be provided on the outer periphery of the cold cathode ray tube 63A except for the portion facing the light guide 63 to further improve the light utilization rate.

The liquid crystal display substrate 62 and the light guide 6 are also provided.
3, there is a support frame 65 in which the cold cathode tube 63A and the cold cathode tube cover 64 are accurately positioned and housed. The support frame body 65 has a box shape and is integrally molded of, for example, synthetic resin, and an appropriate locking portion formed of a protrusion or the like is formed in accordance with the arrangement of the above-mentioned components.

That is, by arranging the parts so that the side end surfaces of the parts come into contact with the locking portions, the parts can be positioned with respect to the support frame 65. The support frame 65 also has a function of a light-shielding cover for preventing light from the cold cathode tubes 63A from leaking in the display direction.

Further, a tablet board 66 is arranged on the back surface of the support frame 65. The tablet board 66 detects the position of the stylus when the stylus, which will be described later, is brought close to the coordinates of the tablet board 66, and displays the coordinate position of the liquid crystal display substrate 62 corresponding to the coordinate position. ing.

Thus, by tracing the transparent substrate 67 constituting the display surface of the liquid crystal display device with the stylus,
The locus is displayed as it is on the liquid crystal display substrate 62.

That is, although the stylus is traced on the display surface of the liquid crystal display substrate 62, a so-called transparent substrate 67 is provided on the main surface side of the liquid crystal display substrate 62.
Are arranged so that they can be traced directly to the surface of the transparent substrate 67. The liquid crystal display substrate 62 is, for example, 2
Since the glass substrates are arranged so as to face each other through the liquid crystal, direct tracing of the surface of the liquid crystal display substrate 62 by the stylus causes the liquid crystal unevenness to be displayed as it is due to the bending of the glass substrate due to the pressure applied. It will be done.

An intermediate layer 1 made of a transparent resin material is preferably provided between the transparent substrate 67 and the liquid crystal display substrate 62.
00 are inserted, and these transparent substrate 67 and intermediate layer 1
00 and the liquid crystal display substrate 62 are optically intimately integrated with each other, and they are combined with the light guide 63 and the cold cathode tube cover 6
4, the support frame 65 and the tablet board 66 are integrated by fitting a metal frame 68 having a U-shaped cross section to each of a pair of side portions in the longitudinal direction of the assembly, thereby forming a modular liquid crystal display. It is a component of the device.

3A and 3B are block diagrams of a liquid crystal display device according to the present invention. FIG. 3A is a plan view, FIG. 3B is a left side view, FIG. 3C is a right side view, and FIG. The same reference numerals as those in FIG. 2 correspond to the same parts.

In the figure (a), line IV-IV, V
Cross-sectional views taken along line -V, line VI-VI, and line VII-VII are shown in FIGS. 4, 5, 6, and 7, respectively.

Next, the liquid crystal display substrate 62, the light guide 63, the cold cathode tube cover 64, the support frame 65, the tablet board 66, the transparent substrate 67, the intermediate layer 100, the metal frame 68 and the like described above will be described in more detail. .

Liquid Crystal Display Substrate 62 FIG. 8 is a perspective exploded view showing an embodiment in which the present invention is applied to an STN type liquid crystal display device. 5 is an optical axis of a uniaxial birefringent member, and 6 is an upper electrode substrate. Liquid crystal alignment direction, 7 is the liquid crystal alignment direction of the lower electrode substrate, 8 is the polarization axis or absorption axis of the upper polarizing plate,
9 is the polarization axis or absorption axis of the lower polarizing plate, 10 is the twist direction of the liquid crystal molecules, 11 is the upper electrode substrate, 12 is the lower electrode substrate, and 15
Is an upper polarizing plate, 16 is a lower polarizing plate, 17 is a semitransparent film, 21,
22 is an alignment film, 31 is an upper electrode, 32 is a lower electrode, 40 is a birefringent member, 50 is a liquid crystal layer, 51 is a notch, 52 is a sealant, 60 is a liquid crystal cell, 62 is a liquid crystal display substrate, and 67 is A transparent substrate, 100 is an intermediate layer.

In the figure, in order to align the liquid crystal molecules between the upper and lower electrode substrates 11 and 12 sandwiching the liquid crystal layer 50 so as to form a twisted helical structure, the upper and lower electrode substrates 11 and 12 are A so-called rubbing method, which is a method of rubbing the surfaces of the alignment films 21 and 22 made of an organic polymer resin made of polyimide, for example, in contact with the liquid crystal 12 with a cloth in one direction, is used. The rubbing direction at this time, that is, the rubbing direction, the rubbing direction on the upper electrode substrate 11 and the rubbing direction 7 on the lower electrode substrate 12 are the alignment directions of the liquid crystal molecules. The two upper and lower electrode substrates 11 and 12 thus oriented are opposed to each other with a gap d1 so that the rubbing directions 6 and 7 intersect each other at about 180 to 360 degrees. The electrode substrates 11 and 12 are adhered to each other by a frame-shaped sealant 52 having a cutout 51 for injecting liquid crystal, and the gap has positive dielectric anisotropy, and a predetermined amount of an optically active substance is added. When the nematic liquid crystal is enclosed, the liquid crystal molecules have a helical molecular arrangement with the twist angle θ in the figure between the electrode substrates. In addition, 31 and 32 are upper and lower electrodes, respectively. A member (hereinafter referred to as a birefringent member) 40 having a birefringence effect on the upper electrode substrate 11 of the liquid crystal cell 60 thus configured.
Are provided, and upper and lower polarizing plates 15 and 16 are provided with the member 40 and the liquid crystal cell 60 interposed therebetween.

A semi-transparent film 17 is provided under the lower polarizing plate 16 and between the backlight and the semi-transparent film 17 and functions in both a reflection mode (when the backlight is not lit) and a transmission mode (when the backlight is lit). It is like this.

An intermediate layer 100 made of a transparent resin is provided between the outer surface of the upper polarizing plate 15 (the surface opposite to the liquid crystal cell) and the transparent substrate 67. Further, the surface of the upper electrode substrate 11 is usually subjected to so-called non-glare treatment for the purpose of preventing light reflection, but in the case of this embodiment, it is not performed, and in the main surface of the transparent substrate 67. It has been given.

The twist angle θ of the liquid crystal molecules in the liquid crystal layer 50.
Is preferably 200 to 300 degrees, but the transmittance −
The range of 230 to 270 degrees is more preferable from the practical viewpoint of avoiding the phenomenon that the lighting state near the threshold value of the applied voltage curve becomes an orientation that scatters light and maintains excellent time division characteristics. . This condition basically makes the response of the liquid crystal molecules to the voltage more sensitive and acts to realize excellent time division characteristics. The refractive index anisotropy [Delta] n ₁ and the product [Delta] n ₁ · d ₁ of the thickness d ₁ of the liquid crystal layer 50 in order to obtain excellent display quality from preferably 0.5 [mu] m 1.0
It is desirable to set in the range of μm, more preferably 0.6 μ to 0.9 μm.

The birefringent member 40 acts to modulate the polarization state of the light passing through the liquid crystal cell 60, and converts what could be colored display by the liquid crystal cell 60 alone into black and white display. Thus the birefringent member 40 refractive index anisotropy [Delta] n ₂ and is extremely important product [Delta] n ₂ · d ₂ of a thickness d _2, preferably 0.8μm from 0.4 .mu.m, more preferably 0.5μm To 0.7 μm.

Further, since the liquid crystal display device 62 according to the present invention utilizes the elliptically polarized light due to the birefringence, the polarizing plate 15,
When the uniaxial transparent birefringent plate is used as the birefringent member 40, the relationship between the 16 axes and the liquid crystal alignment directions 6 and 7 of the electrode substrates 11 and 12 of the liquid crystal cell 60 is extremely important. .

Light guide 63 The light guide 63 is made of a transparent resin body made of, for example, acrylic or the like, and on the side where the main surface facing the liquid crystal display substrate 62 and the cold cathode tube 63 are arranged as described above. A diffuse reflection film is formed except for the side end faces. The diffused reflection film in this case is not necessarily limited to the one adhered to the light guide body 63, and may be the one arranged so as to contact the corresponding surface.

In the case of this embodiment, the cold cathode fluorescent lamp 6 is used.
3A is arranged on one side of the other sides than the longitudinal direction.

Cold-cathode tube cover 64 The cold-cathode tube cover 64 is made of, for example, a synthetic resin material, and functions as a light-shielding cover for introducing light from the cold-cathode tube 63A to the light guide 63 side. I have.

As shown in FIG. 4, this cold cathode tube cover 6
The reference numeral 4 extends so as to be positioned on one side of the light guide 63, and the side end surface of the extension is close to the liquid crystal display substrate 62.

Further, a step portion 64A is formed on the side end surface, and one side portion of the transparent substrate 67 is supported by the step portion 64A. And this transparent substrate 6
The other side of 7 is supported by a spacer 69 made of silicon or rubber, as shown in FIG. That is, the cold cathode tube cover 64 also serves as a support for the transparent substrate 67.

The transparent substrate 67 is supported by the intermediate layer 100 with a certain gap from the display surface of the liquid crystal display substrate 62.

In the above-described embodiment, the case where there is only one cold cathode tube cover 64 has been described, but it may be formed on the other side portions facing each other (thus, there are two cold cathode tube covers). ), In this case, other cold cathode tube covers can have the same configuration.

Support Frame 65 The support frame 65 has a box shape and is made of, for example, a synthetic resin material. The light guide 6 is provided in the support frame 65.
3, the cold cathode tube 63A, the transparent substrate and the liquid crystal display substrate 62 which are optically closely adhered to each other by the intermediate layer 100, and the cold cathode tube cover 64 can be arranged with accurate positioning.

For example, as shown in FIG. 2, the support frame 65 formed by integrally molding a synthetic resin material has a protrusion 95.
Are formed by simultaneous molding. The projection 95 is arranged such that its side surface abuts the side end surface of each component.

Metal frame 68 The metal frame 68 is made of a non-magnetic material such as stainless steel having a U-shaped cross section, and is made of a transparent substrate 67 and a liquid crystal display substrate 6.
2, printed circuit board 62A, light guide 63, cold cathode ray tube 63
A, the front surface of the transparent substrate 67 and the back surface of the tablet board 66 at a pair of sides (upper side and lower side) in the longitudinal direction among the sides of the assembly of the cold cathode ray tube cover 64, the support frame 65, and the tablet board 66. Are fitted to press. As a result, a modularized liquid crystal display device having high mechanical strength is constructed.

In the above structure, all the metal frames 68 are non-magnetic materials.
For example, the portion of the metal frame 68 attached to the lower side of the liquid crystal display device may be a magnetic body.

In this structure, the metal frame 68 is made of a non-magnetic material in any one of them, or is made of a non-magnetic material in one of them. Therefore, in the former case, the periphery of the display surface does not affect the magnetic force, and the stylus position is not detected in error.

In the latter case, the tablet board is mounted by mounting the metal frame 68 at a relatively long distance from the display surface, for example, on the lower side of the display surface (when the metal frame 68 which is not a non-magnetic material is used). The detection of the stylus position at 66 can now be made more reliable.

Tablet Board 66 FIG. 9 is a plan view for explaining an embodiment of the tablet board applied to the liquid crystal display device according to the present invention. As shown in FIG. 9, it corresponds to the display surface of the liquid crystal display substrate 62. A so-called antenna coil is arranged in the detection area 66A. This antenna coil is composed of a plurality of coils arranged at equal intervals in the x-axis direction and a plurality of coils arranged at equal intervals in the y-axis direction.

FIG. 10 is an explanatory view of the detection principle of an embodiment of the tablet board applied to the liquid crystal display device according to the present invention.

As shown in the figure, coils 80A, 80B, 80C, which are arranged in parallel in the x-axis direction at equal intervals ,.
And coils 81A, 81 arranged at equal intervals in the y-axis direction.
B, 81C, ... Are arranged as shown.

By placing a stylus 83, for example, which produces an alternating magnetic flux, close to the plane on which such an antenna coil is formed, the coil 8 in the x direction at the close portion is placed.
A current is generated in 0A and the coil 81C in the y direction. Therefore, the position of the stylus 83 is determined by detecting which coil the current is flowing through to the coordinates (x, y).
You will be able to know by.

Further, a wiring layer area 66B is formed around the detection area 66A in which the antenna coil is formed in this way, in which a wiring layer for extracting the electrode of each coil to the outside is formed.

Further, a notch 66C is formed in the peripheral portion of the tablet board 66. This notch 66C
Is provided, for example, on each of the longitudinal sides, and is provided in proximity to the other side orthogonal to the longitudinal side.

It goes without saying that the tablet board is not limited to the stylus detecting mechanism as described above, and can be constituted by other known detecting means including the function of the stylus.

FIG. 11 is a plan view showing a state where the tablet board is fixed to the support frame in the embodiment of the liquid crystal display device according to the present invention.

In the figure, the notch 66C serves as a screw hole for fixing the tablet board 66 to the support frame 65, and is viewed from the tablet board 66 side fixed with the screw 66D. It is a figure.

In such a structure, since the tablet board 66 is fixed to the supporting frame body 65 by the screw 66D, the positional displacement between the supporting frame body 65 and the tablet board 66 is extremely unlikely to occur. The positional relationship of the tablet board 66 with respect to the support frame body 65 is always maintained as predetermined.

Even when the screws 66D are fixed, the screws 66D can be screwed into the tablet board 66 with the support frame 65 accurately positioned in the through holes of the screws 66D. The displacement of the tablet board 66 with respect to the frame body 65 can be suppressed as much as possible.

Further, in particular, if the screw 66D is screwed into the support frame 65 through the notches formed on the respective sides of the tablet board 66, the size of the tablet board 66 can be minimized. The width of the support frame 65 can be reduced accordingly.

This corresponds to the recent demand that the size of the display surface should be increased as much as possible while the width of the peripheral frame (usually called a frame) should be minimized. .

Transparent Substrate 67 The transparent substrate 67 is a transparent substrate on which the stylus 83, which is a writing means, is directly traced on the main surface.

This embodiment is characterized in that the intermediate layer 100 is installed between the transparent substrate 67 and the liquid crystal display substrate 62.

The intermediate layer 100 fills a space between the transparent substrate 67 and the liquid crystal display substrate 62 with a resin material or the like having a refractive index similar to those of the both substrates to bring them into a bonded state.

A soft soft sheet may be attached to the main surface in order to improve the writing quality with a writing means (stylus). There is no problem even if the surface of this soft sheet is subjected to so-called non-glare treatment with silica spray coating.

Next, the intermediate layer 10 in the embodiment of the present invention.
A method of forming 0 will be described.

(Pretreatment) When the adhesive portion of the intermediate layer 100 is a glass substrate, the surface is cleaned with a solvent such as an alkaline detergent or acetone.

When the portion to which the intermediate layer 100 is adhered is a resin substrate such as a polarizing plate, pretreatment with a neutral detergent or the like is effective.

(Intermediate Layer Forming Method 1) An appropriate spacer is put between both substrates sandwiching the intermediate layer and the periphery is fixed with a tape or the like so that the liquid material before curing which becomes the intermediate layer does not leak. At this time, an injection port for injecting the liquid substance is formed. In addition, the above-mentioned spacer is the same as that shown in FIG.
The spacer 69 shown in 1 may be used as it is.

As the liquid material for the intermediate layer, a polyester resin obtained by adding a suitable cross-linking agent to unsaturated polyester is used as a main component, and a hardening agent is added thereto in a small amount. This is injected through the injection port, and the injection port is closed after the injection.

Then, for example, a heat treatment is applied at 65 ° C. for 50 minutes or longer to cure.

(Intermediate Layer Forming Method 2) As in the forming method 1, the surfaces of both substrates are pretreated.
Urethane resin is used as the liquid material which becomes the intermediate layer.

A small amount of an ultraviolet curing agent is added to this urethane resin, and the urethane resin is injected in the same manner as in the forming method 1 described above. Then, for example, a curing treatment is performed for 15 minutes with an ultraviolet lamp having an output of 0.5 mW / cm ^2. . This intermediate layer is 40 ° C
Can be peeled off with warm water and regenerated.

(Intermediate Layer Forming Method 3) Examples of the intermediate layer forming material include polyethylene, polypropylene, urethane, acryl, phenol, epoxy,
Melanin, nylon, polyimide, polycarbonate,
Appropriate adhesives or pressure-sensitive adhesives are applied to both surfaces of a transparent synthetic resin plate such as butyl, epoxyphenol, vinyl chloride, polyester, and other various gels, and bonded to both substrates. The intermediate layer thus formed can also be peeled off and regenerated by selecting an adhesive material or an adhesive material to be used.

When the above-mentioned transparent synthetic resin plate is used, the adhesive or pressure-sensitive adhesive to be used fixes the both substrates so that they are in optical contact with each other (that is, no air remains on the bonding surface).

12 and 13 are explanatory views showing the surface reflectance of the liquid crystal display device formed by each of the above-mentioned intermediate layer forming methods in comparison with the conventional case in which the intermediate layer is not interposed. FIG. FIG. 13 is a main part configuration diagram of a liquid crystal display device, and FIG. 13 is a comparison diagram of reflectance.

In FIG. 12, the same reference numerals as those in the above embodiment correspond to the same portions, and in FIG. 13, Ra is the reflectance at the interface between air and the transparent substrate 67, and Rb is the transparent substrate 67 and the intermediate layer 1.
00 is the reflectance at the interface, and Rc is the reflectance at the interface between the intermediate layer 100 and the liquid crystal display substrate 62 (upper polarizing plate 15).

As shown in FIG. 13, the total reflectance at each interface of the conventional one having no intermediate layer 100 is 14%, while the total reflectance of the present invention having the intermediate layer 100 is 4. 4%, and that of the present invention is about 1 / compared with the conventional one.
Reduced to 3.

As a result, the light from the window and the reflection of extraneous light such as a fluorescent light are hardly noticed, and the display screen is very easy to see.

The contrast C is defined by the following equation.

C = {brightness of the lit part of the liquid crystal display device (brightness of the liquid crystal display device + external light reflection brightness)} / {brightness of the non-lighted part of the liquid crystal display device (external light reflection brightness)} = 1+ (liquid crystal display (Luminance of device) / (external light reflection luminance) (1) In the configuration of the liquid crystal display device according to the present invention, the reflectance of external light is reduced to 1/3, and as a result, the contrast is about 3 from the formula (1). Doubled, the displayed image becomes clearer.

Another Embodiment of the Present Invention FIG. 14 is a development schematic diagram for explaining another embodiment of the liquid crystal display device according to the present invention, in which 67P is a transparent substrate made of hard-coated glass, 71 is a grid, and The same reference numerals as in the example correspond to the same parts.

In this embodiment, the above-mentioned liquid crystal display device is incorporated in the panel 70. In the configuration shown in the figure, the transparent substrate 67P can be arranged separately from the liquid crystal display device main body.

That is, the liquid crystal display substrate 62 is the panel 70.
The transparent substrate 67P is arranged so as to be exposed on the display surface of the liquid crystal display substrate 62, and the transparent substrate 67P can be arranged above the liquid crystal display substrate 62 via the intermediate layer 100.

Then, a grid 71 for drawing a graph is drawn on the surface of the transparent substrate 67P, which is convenient for drawing the graph.

FIG. 15 is an explanatory view of still another configuration of the transparent substrate in the above-mentioned other embodiment of the present invention, in which, in addition to the transparent substrate 67P, FIGS. c)
As shown in, a transparent substrate 67 in which ruled lines are drawn, respectively.
There are a transparent substrate 67R on which Q and a dot are drawn, and a transparent substrate 67S on which a document frame is drawn, and these can be replaced and arranged on the panel 70 as needed.

With this structure, for example, when writing characters, the transparent substrate 67Q with ruled lines is attached,
When drawing a graph, a transparent substrate 67P on which a grid is drawn can be attached.

Therefore, it becomes possible to make the drawing easy according to the drawing mode of the character or graph.

FIG. 16 is an explanatory view of still another configuration of the transparent substrate in the above-mentioned other embodiment of the present invention. For example, in the case of a transparent substrate 67P in which grids having different dimensions are drawn, its side is shown. A bar code 72 is formed at one location, and a panel 70 is formed with a photodiode array 73 for reading the bar code 72 when the transparent substrate 67P is arranged as shown in FIG. is there.

FIG. 17 is a block diagram for explaining an example of the transparent substrate identification circuit in the above-mentioned other embodiment of the present invention. As shown in FIG. 17, the output from the photodiode array 73 is input to the identification circuit 74. The identification circuit 74 recognizes the type of grid of the transparent substrate 67P currently arranged based on the information stored in the memory 75 in advance. Then, the origin of the liquid crystal display substrate 62 is made to coincide with the origin of the grid by the coordinate conversion circuit 76.

In such a case, the display area of the display surface of the liquid crystal display substrate 62 is substantially narrowed, the calculation for graph display on the liquid crystal display substrate 62 is reduced, and the display response is accelerated. To have.

In the above embodiment, the glass plate is used as the liquid crystal display substrate of the liquid crystal display device. However, in a so-called flexible liquid crystal display device using a flexible resin film as the substrate, a soft sheet is especially formed under the transparent substrate. It is not necessary to interpose, and the above transparent substrate can also be a flexible substrate such as a resin sheet.

[0101]

As described above, according to the present invention,
Since the light transmittance from the liquid crystal display substrate side can be increased and the reflection of external light can be suppressed, the display quality and the visibility of the displayed image can be improved.

Since the intermediate layer can be easily formed, the liquid crystal display device can be manufactured at low cost.

Then, it is possible to provide a pen-input liquid crystal display device which is easy to write when a stylus is in contact.

[Brief description of drawings]

FIG. 1 is a structural diagram schematically illustrating a basic configuration of a liquid crystal display device according to the present invention.

FIG. 2 is a developed perspective view illustrating the overall structure of an embodiment of the liquid crystal display device according to the present invention.

FIG. 3 is a configuration diagram of a liquid crystal display device module according to the present invention.

4 is a cross-sectional view taken along line IV-IV in FIG.

5 is a cross-sectional view taken along the line VV in FIG.

6 is a sectional view taken along line VI-VI in FIG.

7 is a sectional view taken along line VII-VII in FIG.

FIG. 8 is a perspective exploded view showing an embodiment of a liquid crystal display substrate.

FIG. 9 is a plan view illustrating an embodiment of a tablet board applied to the liquid crystal display device according to the present invention.

FIG. 10 is an explanatory diagram of a detection principle of an embodiment of the tablet board applied to the liquid crystal display device according to the present invention.

FIG. 11 is a plan view showing a state where the tablet board is fixed to the support frame in the embodiment of the liquid crystal display device according to the present invention.

FIG. 12 is a main part configuration diagram showing the surface reflectance of the liquid crystal display device according to the present invention in comparison with a conventional case in which an intermediate layer is not interposed.

FIG. 13 is a comparative view of the reflectance showing the surface reflectance of the liquid crystal display device according to the present invention in comparison with the conventional case in which no intermediate layer is interposed.

FIG. 14 is a development schematic view illustrating another embodiment of the liquid crystal display device according to the present invention.

FIG. 15 is an explanatory diagram of still another configuration of the transparent substrate in the other embodiment of the present invention.

FIG. 16 is an explanatory diagram of still another configuration of the transparent substrate in the other embodiment of the present invention.

FIG. 17 is a block diagram illustrating an example of a transparent substrate identification circuit according to another embodiment of the present invention.

FIG. 18 is a sectional view schematically showing a configuration of a conventional pen input type liquid crystal display device.

[Explanation of symbols]

 11 Upper Electrode Substrate 12 Lower Electrode Substrate 15 Upper Polarizing Plate 16 Lower Polarizing Plate 17 Semitransparent Film 40 Birefringent Member 50 Liquid Crystal Layer 52 Sealant 60 Liquid Crystal Cell 62 Liquid Crystal Display Substrate 63 Light Guide 66 Tablet Board 67 Transparent Substrate 67A Non-glare Treatment Surface 67B Soft sheet 67C Glass plate 83 Stylus 100 Intermediate layer 101A Optical path (external light) 101B Optical path (display image light, light source is backlight).

Claims (4)

[Claims] 1. A liquid crystal display substrate, a transparent substrate arranged on the display surface side of the liquid crystal display substrate, and a tablet board arranged on the back surface side of the liquid crystal display substrate, tracing the surface of the transparent substrate. In the liquid crystal display device configured to detect the stylus locus by the tablet board and display the stylus locus on the display surface of the liquid crystal display substrate based on the detection, the transparent substrate and the liquid crystal traced by the stylus. A liquid crystal display device characterized in that an intermediate layer made of a substance having a refractive index similar to those of both substrates is provided between the display substrate and the display substrate. 2. A liquid crystal display substrate, a transparent substrate arranged on the display surface side of the liquid crystal display substrate, and a tablet board arranged on the back surface side of the liquid crystal display substrate, tracing the surface of the transparent substrate. In the liquid crystal display device configured such that the tablet board detects the locus of the stylus, and based on this detection, the locus of the stylus can be displayed on the display surface of the liquid crystal display substrate, on the surface of the transparent substrate traced by the stylus. At least a non-glare layer is formed, and an intermediate layer made of a substance having a refractive index similar to those of the both substrates is provided between the transparent substrate traced by the stylus and the liquid crystal display substrate. Liquid crystal display device. 3. A liquid crystal display device according to claim 1, wherein the intermediate layer is made of a curable resin. 4. The liquid crystal display device according to claim 1, wherein the intermediate layer is in optical contact with the transparent substrate and the liquid crystal display substrate.