JPH11352507A - Liquid crystal device, liquid crystal polarizing switch and display device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal device in which ununiformity will not be generated in the operating characteristic of liquid crystal by reducing effects due to sheet resistances. SOLUTION: A liquid crystal material 14 is held between a first transparent substrate 11 and a second transparent substrate 12, in which transparent electrodes are formed and conductive materials 15, 16 whose the resistivity are lower than that of the transparent electrodes, are formed on external takeoff parts of the first and second transparent electrodes 11, 12. By this constitution, even if voltages are impressed on the end parts of the extraction electrodes, the voltages can be instantaneously impressed on the whole extraction electrodes, and as a result, the symmetry of the distribution of voltage impressed on the liquid crystal is drastically increased in the inside of the surface of pixels.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device used for a liquid crystal polarization shutter for controlling polarization using liquid crystal, and a display device using the same.

[0002]

2. Description of the Related Art Conventionally, a polarizing shutter is disposed in front of a display, and two polarizing plates having different polarization directions are installed on the left and right of the glasses. A technique has been developed in which an image is viewed three-dimensionally by viewing the image (for example, see Japanese Patent Laid-Open No.
05201 publication).

[0003] The above-mentioned liquid crystal polarizing shutter generally has a polarizing plate on one or both sides of a liquid crystal device in which at least a liquid crystal material is sandwiched in a narrow gap between two transparent substrates on which transparent electrodes are formed. It is used by applying a rectangular voltage to the liquid crystal device and switching the polarization of transmitted light.

[0004]

However, when the polarizing shutter is large in size, for example, when used in a large television, the sheet resistance of the transparent electrode affects the polarizing shutter.
The present inventor has clarified that the voltage applied to the transparent electrode is not uniformly applied to the entire liquid crystal device, resulting in a problem that the operation characteristics of the liquid crystal become non-uniform. That is, the voltage applied to the liquid crystal layer decreases as the distance from the voltage application point increases, resulting in non-uniform in-plane response of the shutter.

[0005] Therefore, the above problems will be described in detail below with reference to the drawings.

FIG. 7 shows a plan view and a sectional view of a conventional general liquid crystal device. FIG. 7A shows the case where the extraction electrodes of the opposing first transparent substrate 1 and second transparent substrate 2 are formed in one direction, and FIG. 7B shows the case where the first transparent substrate 1 and the second transparent substrate 2 are formed. This shows a case where the extraction electrodes of the transparent substrate 2 are formed in two directions. FIG. 9 shows a measurement result of a rising response speed as a liquid crystal shutter when a voltage is applied to the extraction electrode of the liquid crystal device shown in FIG. FIG. 8 shows the measurement positions at points A, B, and C shown in FIG.

[0007] The liquid crystal device used for the measurement is formed by forming an ITO transparent electrode on a glass substrate, applying an alignment film, performing an alignment treatment, and then filling a gap having a thickness of 3 μm with a vertical alignment liquid crystal. The size is 20 cm in length and width. 3 of the nearest point A, the middle point B and the farthest point C of the voltage application
At this point, a 90 percent rise response at an applied voltage of 15 V was measured. As is clear from FIG. 9, the rise time was about 1 ms at the location A where the voltage was applied closest, while the result exceeded 5 ms at the location where the voltage was applied farthest. The shutter used for the display can be used with a slight crosstalk when driven at 30 to 60 Hz. However, since the frame rate is 8.3 ms when driven at 120 Hz, it cannot be used as a shutter.

In view of the above problems, the inventor of the present invention has found that the cause of the non-uniformity of the voltage applied to the liquid crystal layer of the liquid crystal polarizing shutter is that the sheet resistance of the transparent electrode formed on the transparent substrate is large. I found something.

Accordingly, it is a primary object of the present invention to provide a liquid crystal device in which the influence of the sheet resistance is reduced and the operating characteristics of the liquid crystal do not become uneven.

[0010]

In order to achieve the above object, a liquid crystal device of the present invention comprises at least a liquid crystal material sandwiched between two transparent substrates on which transparent electrodes are formed,
An electrode material having a lower resistivity than that of the transparent electrode is formed on a portion of the transparent electrode which is taken out of the transparent electrode. According to this configuration, even if a voltage is applied to the end of the extraction electrode, the voltage can be instantaneously applied to the entire extraction electrode.

In the above configuration, if an electrode material having a lower resistivity than the transparent electrode is further formed on the periphery of the transparent electrode, the uniformity of the response speed in the plane can be further improved.

Further, even when the voltage applied to the transparent electrode on the external extraction portion is configured to be higher in the central portion than in the end portion, the uniformity of the response speed in the plane can be improved. As a specific means in this case, the transparent electrode of the external extraction portion is divided into a plurality of parts, an electric resistance is connected to each of the plurality of divided transparent electrodes, and the value of the electric resistance at the end is set at the central part. There is a method of making it larger than the electric resistance value.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid crystal device, a liquid crystal polarization switch and a display device according to an embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows a plan view and a cross-sectional view of a liquid crystal device according to Embodiment 1 of the present invention, which shows one pixel of the liquid crystal device. FIG. 1A shows the opposing first transparent substrate 11.
FIG. 1B shows a case where the extraction electrodes of the first transparent substrate 11 and the second transparent substrate 12 are formed in one direction.
2 shows a case where the extraction electrodes of the transparent substrate 12 are formed in two directions.

First, the case of FIG. 1A will be described.
Although not shown, a transparent electrode (for example, ITO) is formed on the entire surface of the first transparent substrate 11 and the second transparent substrate 12, and the transparent electrodes are arranged so as to face each other. The liquid crystal material 14 is sandwiched between the two transparent substrates. By applying a voltage between the transparent electrodes formed on the two transparent substrates, the direction of the liquid crystal material 14 can be controlled to control the transmission and non-transmission of light.

When a polarizing plate is provided on at least one of the liquid crystal devices, it is possible to obtain a liquid crystal polarization switch that switches the polarization of transmitted light by applying a voltage to the liquid crystal device.

Here, in the liquid crystal device according to the present embodiment, an electrode having a lower resistivity than the transparent electrode is provided on the outside extraction portion of the transparent electrode formed on the first transparent substrate 11 and the second transparent substrate 12. Material is formed.

Specifically, a copper foil is connected by a conductive paste on a portion where the transparent electrode is taken out. With such a configuration, even if a voltage is applied from a part (end) of the extraction electrode as shown by reference numerals 17 and 18 in FIG. It becomes possible. That is, in FIG. 1A, the voltage applied from the left end is also instantaneously applied to the right end. As a result, the symmetry of the distribution of the voltage applied to the liquid crystal is significantly increased in the plane of the pixel, and the liquid crystal switch can be operated at high speed.

Therefore, when a display is arranged in front of the liquid crystal polarization switch and the liquid crystal polarization switch is operated to switch a specific screen displayed on the display between transparent and non-transparent, an image is displayed. The problem based on the talk can be solved.

Although copper foil is used in the above example, instead of electrode materials having low resistivity, Cr, Au, A
A metal material such as 1 can be used. In this case, a metal material that is plated with a hardly corrosive metal material such as Au may be used, and these metal materials may be connected to the transparent electrode with a conductive paste containing a conductive material such as Ag or C. Instead of the copper foil, only a conductive paste containing a conductive material such as Ag or C may be used.

Next, the case of FIG. 1B will be described.
FIG. 1B shows a first transparent substrate 11 and a second transparent substrate 12.
1 shows the case where the extraction electrodes are formed in two directions, and basically the same effects as in the case of FIG. 1A can be obtained.

However, in the example shown in FIG. 1B, two extraction electrodes are formed on the transparent substrate on one side with the pixel region interposed therebetween, and these electrodes are connected by conducting wires. Assuming that the electric resistance of the conductive wire is negligibly small, even if a voltage is applied from a part (end) of the extraction electrode, a voltage can be instantaneously applied to the extraction electrode facing the pixel.

(Embodiment 2) Hereinafter, Embodiment 2 of the present invention.
Will be described with reference to FIGS. Note that also in this embodiment, when a polarizing plate is provided in at least one of the liquid crystal devices, a liquid crystal polarization switch that switches the polarization of transmitted light by applying a voltage to the liquid crystal device can be obtained. When a display is arranged in front of the device, a liquid crystal polarization switch can be operated to switch a specific screen displayed on the display to transmissive or non-transmissive, thereby displaying an image.

First, FIG. 2 shows a plan view and a sectional view of a liquid crystal device according to the present embodiment (for one pixel of the liquid crystal device). FIG. 2A shows the first transparent substrate 21 facing the first transparent substrate 21.
FIG. 2B shows a case where the extraction electrodes of the second transparent substrate 22 and the first transparent substrate 21 are formed in one direction.
The case where the extraction electrode of the transparent substrate 22 is formed in two directions is shown.

The liquid crystal device according to the present embodiment is basically similar to the liquid crystal device according to the first embodiment, except that an electrode material having a lower resistivity than the transparent electrode is provided on the periphery of the transparent electrode. 25 and 26 are formed. That is, as shown in FIG. 2, a material having a low resistivity is formed on the transparent electrode so as to surround the pixel display area. The conductive material having a low resistivity is the same as that of the first embodiment. For example, a metal material such as Cr, Au, Al, or Cu can be formed by vapor deposition, sputtering, or the like.

According to the liquid crystal device of the present embodiment as described above, since the resistance of the entire peripheral portion can be reduced, the uniformity and symmetry are further improved as compared with the first embodiment. Obtained.

FIG. 4 shows a result of measuring a rising response speed as a liquid crystal shutter of the liquid crystal device manufactured according to the present embodiment (when a voltage is applied from one direction of the extraction electrode). The liquid crystal device used here was manufactured by forming an ITO transparent electrode on a glass substrate, applying an alignment film, performing alignment treatment, and then filling a gap with a thickness of 3 μm with vertical alignment liquid crystal. And the size is 20 cm in length and width. As shown in FIG. 3, the measurement points are a point A closest to the voltage application, an intermediate point B, and a point C farthest. FIG. 4 shows a 90% rise response measured at an applied voltage of 15V. As is clear from the results in FIG. 4, the rise time is about 0.6 ms in the places A and B closest to the electrodes, whereas the result is 0.8 ms in the place farthest from the voltage application.
The response speed was significantly improved as compared with the conventional device shown in FIG.

(Embodiment 3) Hereinafter, Embodiment 3 of the present invention.
Will be described with reference to FIGS. 5 and 6. FIG. Note that also in this embodiment, when a polarizing plate is provided in at least one of the liquid crystal devices, a liquid crystal polarization switch that switches the polarization of transmitted light by applying a voltage to the liquid crystal device can be obtained. When a display is arranged in front of the device, a liquid crystal polarization switch can be operated to switch a specific screen displayed on the display to transmissive or non-transmissive, thereby displaying an image.

First, FIG. 5 shows a plan view and a sectional view of a liquid crystal device according to the present embodiment (for one pixel of the liquid crystal device). FIG. 5 shows a case where the extraction electrodes of the opposing first transparent substrate 31 and second transparent substrate 32 are formed in one direction, but the present embodiment is different from the above-described embodiment. As in the first and second embodiments, the first transparent substrate and the second
The present invention can also be applied to a case where the extraction electrode of the transparent substrate is formed in two directions.

According to the liquid crystal device of the second embodiment, the response speed can be made uniform in the plane as compared with the conventional one, but as shown in FIG. Since the voltage is more likely to be applied to the portion, the response speed is slightly worse in the central portion, and there is still an uneven portion in view of the uniformity of the entire surface (that is, points A and C).
The response speed at the point is slightly lower than the response speed at the point B.)

Therefore, the liquid crystal device of the present embodiment is configured such that the voltage applied to the transparent electrode on the external extraction portion is higher at the center than at the ends.

As a specific means, the transparent electrode at the outside extraction portion is divided into a plurality of parts, an electric resistance is connected to each of the plurality of divided transparent electrodes, and the value of the electric resistance at the end is changed to the electric resistance at the center. The resistance is made larger than the resistance (the low resistance layer formed on the transparent electrode is divided so that the voltage applied to the end is smaller than the voltage applied to the center). Explaining with reference to FIG. 5, the take-out transparent electrode is divided into three, divided into two groups of a central part and a peripheral part, and a first conductive material 35 and a second conductive material 36 are formed thereon. . A resistor of R1 is inserted between the end group and the input line, and a resistor of R2 is inserted between the end group and the input line, and a voltage drop due to the resistance is used. As a specific example, R1 is 1 kΩ,
Drive is performed by connecting 0Ω (that is, short circuit) to R2.

FIG. 6 shows the measurement results of the characteristics of the liquid crystal device according to the present embodiment prepared as described above (measurement positions are the same as in the above-described second embodiment). The response speed at the end is slightly reduced by the connection of the resistor, but the uniformity of the entire surface is improved. The selection of the resistance value used here depends on the sheet resistance of the transparent electrode. The greater the sheet resistance, the greater the effect and the greater the difference between the applied voltages.

The sheet resistance of the transparent electrode depends on the material of the transparent substrate. When the transparent substrate is made of glass, the sheet resistance after the formation of the ITO electrode is about several tens of ohms / square centimeter because the substrate is easily heated. However, when a resin is used for the transparent substrate, the sheet resistance increases by about one digit due to film formation at room temperature and becomes about several hundreds Ω / cm 2. Thus, the effects of the present invention appear significantly.

The liquid crystal device according to the embodiment of the present invention has been described in detail above. This liquid crystal device is used for a liquid crystal polarizing shutter, and the liquid crystal shutter is used for stereoscopic display for left and right images for binocular vision. As a separation shutter, C
Installed in front of RT, turn on applied voltage in synchronization with screen,
By turning it off, it was possible to function as a polarizing shutter for a large screen display, and the observer could easily stereoscopically view by using polarized glasses having left and right polarized lights different from each other. In addition, the use of the liquid crystal shutter sufficiently supports a frequency of 120 Hz, which is a frequency at which flicker is not perceived.

The liquid crystal material used in the present invention includes:
In addition to the vertically aligned liquid crystal, a nematic liquid crystal, a ferroelectric liquid crystal, an antiferroelectric liquid crystal, a ferroelectric liquid crystal polymer, or the like can be used.

[0037]

As described above, according to the present invention, the voltage applied to the liquid crystal layer can be increased by enlarging the transparent electrode portion of the liquid crystal device and forming a conductive material layer having a smaller sheet resistance on the transparent electrode. Non-uniformity can be reduced, the response speed of the liquid crystal can be increased, and the in-plane uniformity can be improved. The present invention exhibits a remarkable effect particularly in a liquid crystal panel having a large size such as a liquid crystal polarization shutter or a liquid crystal panel using a resin substrate.

[Brief description of the drawings]

FIG. 1 is a plan view and a cross-sectional view of a liquid crystal device according to Embodiment 1 of the present invention.

FIG. 2 is a plan view and a cross-sectional view of a liquid crystal device according to Embodiment 2 of the present invention.

FIG. 3 is a diagram showing a measurement position of a rising response speed as a liquid crystal shutter of a liquid crystal device created according to a second embodiment of the present invention;

FIG. 4 is a view showing a result of measuring a rising response speed as a liquid crystal shutter of the liquid crystal device manufactured according to the second embodiment of the present invention;

FIG. 5 is a plan view and a cross-sectional view of a liquid crystal device according to Embodiment 3 of the present invention.

FIG. 6 is a diagram showing a result of measuring a rising response speed as a liquid crystal shutter of the liquid crystal device manufactured according to the third embodiment of the present invention;

FIG. 7 is a plan view and a cross-sectional view of a conventional liquid crystal device.

FIG. 8 is a diagram showing a measurement position of a rising response speed as a liquid crystal shutter of a conventional liquid crystal device.

FIG. 9 is a diagram showing a measurement result of a rising response speed as a liquid crystal shutter of a conventional liquid crystal device.

[Explanation of symbols]

 1, 11, 21, 31 First transparent substrate 2, 12, 22, 32 Second transparent substrate 3, 13, 23, 33 Sealing seal 4, 14, 24, 34 Liquid crystal material 15, 25, 35 Conductive material 16, 26, 36 Conductive material 17, 27, 37 First extraction electrode 18, 28, 38 Second extraction electrode

 ──────────────────────────────────────────────────の Continued on front page (72) Inventor Katsumi Adachi 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (7)

[Claims] 1. A liquid crystal material is sandwiched between at least two transparent substrates on which a transparent electrode is formed, and an electrode material having a lower resistivity than the transparent electrode is formed on a portion from which the transparent electrode is taken out. A liquid crystal device. 2. The liquid crystal device according to claim 1, wherein an electrode material having a lower resistivity than the transparent electrode is further formed on a peripheral portion of the transparent electrode. 3. The liquid crystal device according to claim 1, wherein a voltage value applied to the transparent electrode on the external take-out portion is higher in a central portion than in an end portion. 4. A transparent electrode at an outside extraction portion is divided into a plurality of parts, an electric resistance is connected to each of the plurality of divided transparent electrodes, and a value of the electric resistance at an end portion is larger than a value of the electric resistance at a central portion. 2. The liquid crystal device according to claim 1, wherein the size is increased. 5. A metal material mainly composed of Cr, Au, or Al, or a conductive paste containing a conductive material of Ag or C, as an electrode material having a lower resistivity than the transparent electrode. The liquid crystal device according to claim 1. 6. A liquid crystal material is sandwiched between at least two transparent substrates on which a transparent electrode is formed, and an electrode material having a lower resistivity than the transparent electrode is formed on an external extraction portion of the transparent electrode. A polarizing plate is provided on at least one of the liquid crystal devices, and a voltage is applied to the liquid crystal device to switch polarization of transmitted light. 7. A liquid crystal material is sandwiched between at least two transparent substrates on which a transparent electrode is formed, and an electrode material having a lower resistivity than the transparent electrode is formed on a portion from which the transparent electrode is taken out. A polarizing plate is provided on at least one of the liquid crystal devices, a liquid crystal polarization switch that switches the polarization of light transmitted by applying a voltage to the liquid crystal device, and a display disposed in front of the liquid crystal polarization switch, A display device, wherein a specific screen displayed on the display is switched between transparent and non-transparent by operating a liquid crystal polarization switch.