JPH0667020A - Optical control plate and display element using the same - Google Patents

Abstract

PURPOSE:To enable only the observer existing in the direction of a specific angle of field of view with respect to various display elements to be provided with information by providing the input of the light having plural vibration vector directions with the axis of absorption in the direction normal to the plane direction of a flat planar optical control plate (polarizer) as a means for limiting the angle of field of view of the display elements. CONSTITUTION:A light source 11 which emits ordinary light having various vibrations spectra of, for example, the display element 10 for signal light has a red, yellow or blue light condenser lens 12 on the front surface and further the optical control plate 13 which is formed of polyvinyl alcohol and has the axis of absorption in the direction normal to the plane direction is installed on the front surface thereof. This control plate 13 is easily produced by using polyvinyl alcohol which is a high-molecular resin. Namely, the main chains of the high polymer are rearranged in the stretching direction by uniformly stretching the film in its thickness direction or the main chains of the high- molecular resin are rearranged in the direction perpendicular to the compressing direction by compressing the film under an equal pressure in all the directions of the film plane, by that, the polarizer is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical control plate used for a display device.

[0002]

2. Description of the Related Art A signal lamp installed in a transportation facility intentionally limits a viewing angle by using a lens so that only an observer who should follow an instruction from the signal lamp can visually recognize it. Further, in order to limit the viewing angle, a method of providing a hood or a lattice (louver) on the front surface of the signal light is also used.

Further, a display element used in an automatic cash deposit / withdrawal device (hereinafter referred to as an ATM machine) installed in a financial institution or the like, or an element having both a display function and an input function (display switch panel (product name touch panel) )) Is similar to the above signal light from the viewpoint of personal information protection.
It is desirable that the viewing angle is limited so as to limit the number of viewers who can see it, but such a mechanism for limiting the viewing angle is not often used.

[0004]

When there are a large number of signal lights on a straight road or a signal light on a multi-forked road, a large number of signal lights are observed in addition to the signal lights to be originally observed, and the error of the signal lights to be observed is incorrect. It was tied to recognition. With respect to these problems, the visibility of the signal lights to be observed has been improved by mounting the signal lights downward on a straight road and by narrowing the viewing angle to limit the viewing angle by providing a hood or a grid on a multi-road road. However, since the reflection of the light on the hood and the grid and the surface emission of the signal lamp cause surface emission, these methods cannot sufficiently limit the viewing angle, and are insufficient to eliminate erroneous recognition of the signal lamp to be observed.

Further, in a display element used in a money depositing / dispensing machine (ATM) installed in a financial institution or a display switch panel, the element itself has almost no view angle limiting measure. However, depending on how the device is installed, there is a risk that the personal identification number, transaction amount, and deposit / saving balance will be leaked to other users around.

As a method of limiting the viewing angle of these display elements, an optical louver (Shoichi Matsumoto and Ichiyoshi Tsunoda: Fundamentals and Applications of Liquid Crystals, Chapter 10, 9.2 (Industrial Research Board, 1991))
However, it is difficult to use a device having a large capacity and a high definition display due to the problem of louver pitch control. Further, the method using the optical louver also causes the element to become thick. Further, there is a fiber optics plate in which thin optical fibers are bundled into a plate shape, but there is a drawback that it is expensive in terms of manufacturing.

The present invention eliminates the above-mentioned disadvantages.

[0008]

SUMMARY OF THE INVENTION In order to solve these problems, the present invention, as means for limiting the viewing angle of any display element, has a plate-like optical structure for inputting light having a plurality of vibration vector directions. An optical control plate (polarizer) characterized by having an absorption axis in a direction normal to the plane direction of the control plate (polarizer), or an angle formed by the absorption axis and the above-mentioned optical control plate (polarizer) plane ( The smaller one, θ, is 10 ≦ θ ≦ 90 °, and an optical control plate (polarizer) is installed to limit the viewing angle of the display element to solve the above problems.

[0009]

The polarizer is an optical control plate that transmits only light in a specific vibration vector direction to the input of light having various vibration vector directions. That is, it is an element having a function of selectively absorbing light having a specific vibration vector direction. Generally, conventionally used polarizers have a characteristic of absorbing a specific vibration vector direction in a plane direction, and use a function of converting natural light into linearly polarized light. Polarized glasses (sunglasses)
Has been applied to.

On the other hand, the display element of the present invention has the structure shown in FIG.
As shown in (a), the normal direction dn to the plane direction dp
The optical control plate 1 composed of a polarizer having a light absorption axis is installed in front of the display light, and as shown in FIG. 1 (b), the optical control plate 1 has a plurality of vibration vector directions. With respect to the incident natural light 2, the incident light 2a having a larger angle i with the normal direction of the polarizer has a transmission distribution characteristic 2b in which the incident light 2a is not transmitted but is absorbed. By using this characteristic, the viewing angle can be limited, and in particular, in a liquid crystal display element or the like that controls polarization, a specific viewing angle limitation can be achieved by combining the outgoing polarized light and the polarizer of the present invention. It will be possible. Therefore, the viewing angle can be selectively limited only to the direction in which information is to be provided (viewer direction).

[0011]

EXAMPLES The present invention will be specifically described below with reference to examples.

(Embodiment 1) FIG. 2 shows the structure of a signal lamp display element 10 using the present invention.

A light source 11 which emits normal light having various vibration vectors has a red, yellow or blue colored condenser lens 12 on its front surface, and further has a thickness of about 200 μm made of polyvinyl alcohol on its front surface. An optical control plate 13 having an absorption axis in a direction normal to the plane direction of was installed.

This control plate can be easily made of a polymer resin polyvinyl alcohol by the following manufacturing method.

As shown in FIG. 6, two hard plates 41 having excellent flatness are prepared, one of them has a polyvinyl alcohol material 42 which is a polymer resin of a polarizer in the center thereof, and the surrounding thereof has room temperature to high temperature, for example, 300. A liquid substance 43 having a stable chemical property at a temperature of 0 ° C. was provided, and an ultraviolet curable resin 44 mixed with a spacer 45 was provided outside the liquid substance 43. After installing the materials as shown in FIG. 7, the other plate 51 is attached, the polarizer material 42 is melted by heating, and the film is pressed to a desired film thickness (spacer 45 diameter) to fix the plate-to-plate spacing. UV curable resin 4
4 was cured. Further heating causes the material to expand. Finally, by cooling and compressing the material as shown in FIG. 8,
It is possible to obtain a film having a uniform optical characteristic having the absorption axis of this embodiment even in a large area.

That is, by uniformly stretching the film in the thickness direction of the film and rearranging the polymer main chain in the stretching direction, or by performing equal pressure compression in all the plane directions of the film as described above, the direction of the compression force is changed. The polymer backbone is rearranged in the vertical direction to obtain a polarizer.

When the viewing angle of the signal light display device of this example was measured, it was found that large transmitted light could be obtained in the direction normal to the plane direction of the polarizer, and the viewing angle was limited. This was more effective in limiting the viewing angle than the one in which the hood or grating was installed in front of the signal lamp.

(Embodiment 2) FIG. 3 shows a preferred embodiment in which the present invention is applied to a liquid crystal display element for an ATM machine.

Vertically aligned nematic liquid crystal display device (V
The AN type liquid crystal display element) is composed of a driving liquid crystal display cell 14 and polarizing plates 15 and 16 installed on both surfaces thereof, a backlight flat light source 17 on the rear side, and a normal line to the front side on the observer side with respect to the plane direction. Optical control plate 1 having absorption axis 18a in the direction
8 was installed. When the viewing angle of this liquid crystal display device was measured, it was found that large transmitted light could be obtained in the direction normal to the plane direction of the polarizer, and the viewing angle was limited to the front. This makes it impossible to visually recognize from outside the specific area, which is advantageous for confidentiality of information.

(Embodiment 3) FIG. 4 shows an ATM using the present invention.
The structure of the color cathode-ray tube display 20 for machines is shown.

A color cathode ray tube (C
An optical control plate 22 having a plane perpendicular to the cathode ray tube axis 21a is installed on the front surface of the RT) 21. The optical control plate 22 is a polarizer having an absorption axis at an angle α of, for example, 70 ° with respect to the plane direction thereof, and is installed so that the absorption axis direction and the observer direction 23 coincide with each other. When the viewing angle of this display was measured, it was found that large transmitted light could be obtained in the direction of 70 ° with respect to the plane direction of the optical control plate, and the viewing angle was limited. As a result, 60 ° to 80 ° around 70 °
It is not possible to see from outside the specific area of °, which is advantageous for confidentiality of information.

(Embodiment 4) An embodiment in which the function of a display switch panel is added to an optical control plate having an absorption axis in a direction perpendicular to the plane direction used in Embodiment 2 will be described.

FIG. 5 shows the structure of the viewing angle limited display switch panel 30. The display switch panel activates the switch by touching the panel surface with your finger.
Installed on the display surface of TM machine.

That is, the transparent electrode 32 is formed directly on the optical control plate having the absorption axis 31a in the direction perpendicular to the plane direction, and then the optical control plate 31 with stripe electrodes is stripe-opposed. A display angle limited display switch panel was prepared by combining with the substrate 34 having the electrodes 33 formed thereon. The same viewing angle limitation as in Example-2 could be realized, and the function of the display switch panel could be added by using the polarizer of the present invention.

[0025]

According to the present invention, it becomes possible to provide information to various display elements only to an observer in a specific viewing angle direction. For example, by limiting the viewing angle of the signal light, it is possible to see only from the specific viewing angle direction of the signal light, and it is possible to reduce false recognition of the signal light when there are many signal lights on a straight road or on a multi-road. Becomes In addition, by limiting the viewing angle of the display of the automatic cash deposit / withdrawal device installed in financial institutions, etc., it is possible to reduce the leakage of personal confidential information such as personal identification numbers, transaction amounts and deposit / savings balances to others. It becomes possible.

Further, the viewing angle is limited only in the vertical direction,
In order to perform various viewing angle restrictions such as making it visible only to the front, it is preferable to combine with a polarizer having an absorption axis in the plane direction.

Further, as compared with the conventional method of limiting the viewing angle using the optical louver, a thin display element having a more limited viewing angle and suitable for high-definition display with a large capacity can be easily provided. It has become possible.

Although only the LCD and CRT have been described in the present embodiment, it goes without saying that similar effects can be obtained with display elements such as PD, EL and LED.

[Brief description of drawings]

1A is a perspective view illustrating an optical control plate according to the present invention, FIG. 1B is a schematic view illustrating a viewing angle of the optical control plate in FIG.

FIG. 2 is a schematic diagram of an embodiment of the present invention.

FIG. 3 is an exploded perspective view of another embodiment of the present invention,

FIG. 4 is a schematic cross-sectional view of another embodiment of the present invention,

FIG. 5 is an exploded perspective view of another embodiment of the present invention.

FIG. 6 is a schematic view showing the manufacturing process of the optical control plate of the embodiment of the present invention,

FIG. 7 is a schematic cross-sectional view showing the manufacturing process of the optical control plate according to the embodiment of the invention.

FIG. 8 is a schematic cross-sectional view showing the manufacturing process of the optical control plate according to the embodiment of the invention.

[Explanation of symbols]

 1, 13, 23, 31 ... Optical control plate

[Procedure amendment]

[Submission date] December 8, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Optical control plate and display device using the same

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical control plate used for a display device.

[0002]

2. Description of the Related Art A signal lamp installed in a transportation facility intentionally limits a viewing angle by using a lens so that only an observer who should follow an instruction from the signal lamp can visually recognize it. Further, in order to limit the viewing angle, a method of providing a hood or a lattice (louver) on the front surface of the signal light is also used.

Further, a display element used in an automatic cash deposit / withdrawal device (hereinafter referred to as an ATM machine) installed in a financial institution or the like, or an element having both a display function and an input function (display switch panel (product name touch panel) )) Is similar to the above signal light from the viewpoint of personal information protection.
It is desirable that the viewing angle is limited so as to limit the number of viewers who can see it, but such a mechanism for limiting the viewing angle is not often used.

[0004]

When there are a large number of signal lights on a straight road or a signal light on a multi-forked road, a large number of signal lights are observed in addition to the signal lights to be originally observed, and the error of the signal lights to be observed is incorrect. It was tied to recognition. With respect to these problems, the visibility of the signal lights to be observed has been improved by mounting the signal lights downward on a straight road and by narrowing the viewing angle to limit the viewing angle by providing a hood or a grid on a multi-road road. However, since the reflection of the light on the hood and the grid and the surface emission of the signal lamp cause surface emission, these methods cannot sufficiently limit the viewing angle, and are insufficient to eliminate erroneous recognition of the signal lamp to be observed.

Further, in a display element used in a money depositing / dispensing machine (ATM) installed in a financial institution or a display switch panel, the element itself has almost no view angle limiting measure. However, depending on how the device is installed, there is a risk that the personal identification number, transaction amount, and deposit / saving balance will be leaked to other users around.

As a method of limiting the viewing angle of these display elements, an optical louver (Shoichi Matsumoto and Ichiyoshi Tsunoda: Fundamentals and Applications of Liquid Crystals, Chapter 10, 9.2 (Industrial Research Board, 1991))
However, it is difficult to use a device having a large capacity and a high definition display due to the problem of louver pitch control. Further, the method using the optical louver also causes the element to become thick. Further, there is a fiber optics plate in which thin optical fibers are bundled into a plate shape, but there is a drawback that it is expensive in terms of manufacturing.

The present invention eliminates the above-mentioned disadvantages.

[0008]

SUMMARY OF THE INVENTION In order to solve these problems, the present invention, as means for limiting the viewing angle of any display element, has a plate-like optical structure for inputting light having a plurality of vibration vector directions. An optical control plate (polarizer) characterized by having an absorption axis in a direction normal to the plane direction of the control plate (polarizer), or an angle formed by the absorption axis and the above-mentioned optical control plate (polarizer) plane ( The smaller one, θ, is 10 ≦ θ ≦ 90 °, and an optical control plate (polarizer) is installed to limit the viewing angle of the display element to solve the above problems.

[0009]

The polarizer is an optical control plate that transmits only light in a specific vibration vector direction to the input of light having various vibration vector directions. That is, it is an element having a function of selectively absorbing light having a specific vibration vector direction. Generally, conventionally used polarizers have a characteristic of absorbing a specific vibration vector direction in a plane direction, and use a function of converting natural light into linearly polarized light. Polarized glasses (sunglasses)
Has been applied to.

On the other hand, the display element of the present invention has the structure shown in FIG.
As shown in (a), the normal direction dn to the plane direction dp
The optical control plate 1 composed of a polarizer having a light absorption axis is installed in front of the display light, and as shown in FIG. 1 (b), the optical control plate 1 has a plurality of vibration vector directions. With respect to the incident natural light 2, the incident light 2a having a larger angle i with the normal direction of the polarizer has a transmission distribution characteristic 2b in which the incident light 2a is not transmitted but is absorbed. By using this characteristic, the viewing angle can be limited, and in particular, in a liquid crystal display element or the like that controls polarization, a specific viewing angle limitation can be achieved by combining the outgoing polarized light and the polarizer of the present invention. It will be possible. Therefore, the viewing angle can be selectively limited only to the direction in which information is to be provided (viewer direction).

[00011]

EXAMPLES The present invention will be specifically described below with reference to examples.

(Embodiment 1) FIG. 2 shows the structure of a signal lamp display element 10 using the present invention.

A light source 11 for emitting normal light having various vibration vectors has a red, yellow, or blue colored condenser lens 12 on its front surface, and further has a thickness of about 200 μm made of polyvinyl alcohol on its front surface. An optical control plate 13 having an absorption axis in a direction normal to the plane direction of was installed.

This control plate can be easily made of a polymer resin polyvinyl alcohol by the following manufacturing method.

As shown in FIG. 6, two hard plates 41 having excellent flatness are prepared, a polyvinyl alcohol material 42 of a polymer resin for a polarizer is provided in the center of one of the plates 41, and a room temperature to a high temperature, for example, 300 is provided around the polyvinyl alcohol material 42. A liquid substance 43 having a stable chemical property at a temperature of 0 ° C. was provided, and an ultraviolet curable resin 44 mixed with a spacer 45 was provided outside the liquid substance 43. After installing the material as shown in FIG. 7, the other plate 41 is attached, and the polarizer material 42 is melted by heating to a desired film thickness (spacer 45 diameter).
Then, the ultraviolet curable resin 44 was cured to fix the space between the plates. Further heating causes the material to expand.
Finally, by cooling and compressing the material as shown in FIG. 8, it is possible to obtain a film having a uniform optical characteristic having the absorption axis of this embodiment even in a large area.

That is, by uniformly stretching the film in the film thickness direction and rearranging the polymer main chain in the stretching direction, or by performing equal pressure compression in all the plane directions of the film as described above, The polymer backbone is rearranged in the vertical direction to obtain a polarizer.

When the viewing angle of the signal light display element of this example was measured, it was found that a large transmitted light could be obtained in the direction normal to the plane of the polarizer, and the viewing angle was limited. This was more effective in limiting the viewing angle than the one in which the hood or grating was installed in front of the signal lamp.

(Embodiment 2) FIG. 3 shows a preferred embodiment in which the present invention is applied to a liquid crystal display device for an ATM machine.

The vertically aligned nematic type liquid crystal display element (VAN type liquid crystal display element) is a driving liquid crystal display cell 14.
And the polarizing plates 15 and 16 installed on both sides thereof,
Backlight flat light source 17 on the rear side, on the observer side in front,
The optical control plate 18 having the absorption axis 18a in the direction normal to the plane direction was installed. When the viewing angle of this liquid crystal display device was measured, it was found that large transmitted light could be obtained in the direction normal to the plane direction of the polarizer, and the viewing angle was limited to the front. This makes it impossible to visually recognize from outside the specific area, which is advantageous for confidentiality of information.

(Example 3) FIG. 4 shows an AT using the present invention.
The structure of the color cathode ray tube display 20 for M machines is shown.

The front of a color cathode ray tube (CRT) 21 housed in a housing 24 absorbs light in the plane direction.
Axis of the optical control plate 22 of 10 ° ≦ θ ≦ 90 °, to Installation perpendicular to CRT tube axis 21a. The optical control plate 22 is a polarizer having an absorption axis at an angle α of, for example, 70 ° with respect to the plane direction thereof, and is installed so that the absorption axis direction and the observer direction 23 coincide with each other. When the viewing angle of this display was measured, it was found that large transmitted light could be obtained in the direction of 70 ° with respect to the plane direction of the optical control plate, and the viewing angle was limited. As a result, visual recognition is not possible from a specific area of 60 ° to 80 ° around 70 °, which is advantageous for confidentiality of information.

(Embodiment 4) An embodiment in which the function of a display switch panel is added to an optical control plate having an absorption axis in a direction perpendicular to the plane direction used in Embodiment 2 will be described.

FIG. 5 shows the structure of the viewing angle limited display switch panel 30. The display switch panel activates the switch by touching the panel surface with a finger, etc.
Installed on the display surface of ATM machines.

That is, the transparent electrode 32 is directly provided on the optical control plate having the absorption axis 31a in the direction perpendicular to the plane direction.
Then, the obtained optical control plate 31 with stripe electrodes was combined with the substrate 34 on which the stripe counter electrodes 33 were formed to form a viewing angle limited display switch panel. The same viewing angle limitation as in Example 2 could be realized, and the function of the display switch panel could be added by using the polarizer of the present invention.

[00025]

According to the present invention, it becomes possible to provide information to various display elements only to an observer in a specific viewing angle direction. For example, by limiting the viewing angle of the signal light, it is possible to see only from the specific viewing angle direction of the signal light, and it is possible to reduce false recognition of the signal light when there are many signal lights on a straight road or on a multi-road. Becomes In addition, by limiting the viewing angle of the display of the automatic cash deposit / withdrawal device installed in financial institutions, etc., it is possible to reduce the leakage of personal confidential information such as personal identification numbers, transaction amounts and deposit / savings balances to others. It becomes possible.

Further, in order to limit various viewing angles such as limiting the viewing angle only in the vertical direction and making it visible only in the front, it is preferable to combine with a polarizer having an absorption axis in the plane direction.

Further, as compared with the conventional method of limiting the viewing angle using an optical louver, a thin display element with a more limited viewing angle and suitable for high-capacity and high-definition display can be easily provided. It has become possible.

Although only the LCD and CRT have been described in this embodiment, it goes without saying that similar effects can be obtained with display elements such as PD, EL, and LEDs.

[Brief description of drawings]

1A is a perspective view illustrating an optical control plate according to the present invention, FIG. 1B is a schematic view illustrating a viewing angle of the optical control plate in FIG.

FIG. 2 is a schematic diagram of an embodiment of the present invention.

FIG. 3 is an exploded perspective view of another embodiment of the present invention,

FIG. 4 is a schematic cross-sectional view of another embodiment of the present invention,

FIG. 5 is an exploded perspective view of another embodiment of the present invention.

FIG. 6 is a schematic view showing the manufacturing process of the optical control plate of the embodiment of the present invention,

FIG. 7 is a schematic cross-sectional view showing the manufacturing process of the optical control plate according to the embodiment of the invention.

FIG. 8 is a schematic cross-sectional view showing the manufacturing process of the optical control plate according to the embodiment of the invention.

[Explanation of reference numerals] 1, 13, 23, 31 ... Optical control plate

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 4

[Correction method] Change

[Correction content]

[Figure 4]

Claims (3)

[Claims] 1. A flat optical control plate which absorbs light in a specific vibration vector direction with respect to light input having a plurality of vibration vector directions, wherein the light is transmitted in a direction normal to the plane direction of the optical control plate. An optical control plate having an absorption axis 2. A flat optical control plate that absorbs light having a plurality of vibration vector directions and absorbs light in a specific vibration vector direction, and an angle formed between the absorption axis of the light and the plane of the optical control plate described above. θ (smaller) is 10 ≦ θ ≦ 90 °, which is an optical control plate. 3. A device for emitting display light, and a light control plate provided on the front surface of the device and having an absorption axis of light in the normal direction. The light control plate controls the control plate surface of the display light. Display element that limits the viewing angle by absorbing more obliquely incident components