JPS62147434A - Liquid crystal optical shutter - Google Patents

Abstract

PURPOSE:To improve response and contrast by providing >=2 kinds of modes of each liquid crystal cell determined by the orientation configuration of molecules of liquid crystal and the combination of the orientation configuration and the axis of polarization of a polarizing plate. CONSTITUTION:A liquid crystal optical shutter is formed by laminating the 1st liquid crystal cell 20 and the 2nd liquid crystal cell 21. The 1st liquid crystal cell 20 changes in mode (cutoff-transmission mode) from a dark visual field to transmission when applied with a voltage and the 2nd liquid crystal cell 21 changes in mode (transmission-cutoff mode) from transmission to the dark visual field when applied with a voltage. This liquid crystal optical shutter composed of the 1st and the 2nd liquid crystal cells 20 and 21 is applied with an opposite-phase voltage to alternate the transmission state and cutoff state. Consequently, optical shutter effect with a high response speed is obtained when light is transmitted and cut off according to whether the voltage is applied or not, and the contrast is improved by employing multilayered structure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a liquid crystal optical shutter, and particularly to one with improved response and contrast.

(Prior Art) Liquid crystal light shutters have been known that transmit or block light by changing the arrangement of molecules in accordance with the positive voltage applied.

As shown in Fig. M4, this liquid crystal optical jammer is made by sequentially applying transparent electrodes 3, 4 and alignment films 5, 6 to the inner surfaces of a pair of glass substrates 1, 2 facing each other with an interval of approximately 10 Cpm. It is generally known that a layered structure is formed, a polarizing plate 1.8 is attached to each outer surface, and a twisted nematic TN liquid crystal 9 is sealed between each of these glass substrates 1.2.

(Problems to be Solved by the Invention) However, in the liquid crystal optical shutter configured as described above, the response time of the liquid crystal 9 to on/off of a voltage signal is slow, and it is difficult to apply a voltage as shown in FIG. 5(A), for example. stone and
The amount of transmitted light transmitted through the liquid crystal 9 has a particularly long fall time, as shown in () in the same figure, and has a problem of poor responsiveness.

For this reason, when such a liquid crystal optical shutter is used as a high-speed multiplex shutter that is turned on and off at high speed, there is a certain limit to how high the speed can be increased.

In addition, if the cell gap of the liquid crystal light shutter is made thinner in order to improve the responsiveness of the liquid crystal, the contrast deteriorates. A problem arises in that the amount of transmitted light decreases.

(Means for solving the problem) The present invention has been made in view of the above-mentioned circumstances.
It is an object of the present invention to provide a liquid crystal optical shutter that can improve responsiveness and contrast at the same time.

In order to achieve the above object, the present invention provides a liquid crystal optical shutter as shown in FIG. 1, in which a pair of substrates 10. The liquid AI 4 , 15 inserted between it and 12.13 and each of the above substrates 10.11 and 12.1
The above liquid crystals 14 and 15 are stacked on 3 and 4mg of 1lEFl is applied! 22, 23, 26.

A plurality of liquid crystal cells 20.21 having the above-mentioned liquid crystal cells 20.21 and 21 are stacked, and the above-mentioned Each liquid crystal cell 20, 21 has two or more modes.

(Function) In the liquid crystal light shutter constructed as described above, by constructing the liquid crystal light shutter from the liquid crystal cells 20 and 21 of (Ia), the light shielding property can be improved. can be improved.

In addition, by making the liquid crystal cells 20.21 multi-layered, each liquid crystal cell 20.21 can be
The cell gap can be made thinner, which can improve responsiveness.

(Example) Hereinafter, a detailed example according to the present invention will be explained using Figures 1 to 3.

FIG. 1 is a diagram showing a liquid crystal light shutter according to this embodiment, and this liquid crystal light shutter is formed by laminating a first liquid crystal cell 20 and a second liquid crystal cell 21. As shown in FIG.

In this embodiment, the first liquid crystal cell 20 is
The second liquid crystal cell 21 is in a mode that changes from dark field to transmission when a voltage is applied (blocking-transmission mode). - cut-off mode).

That is, the first liquid crystal cells 20 are spaced apart from each other by approximately 5 μm.
A pair of glass substrates 10.11 facing each other with an interval of about
Transparent electrodes 22, 23 and alignment films 24. '2
5't-A layer respectively and this glass substrate 10.
Between 11 and 11, a twisted O-Matic liquid crystal 14 made by adding cholesteric liquid crystal (Ch liquid crystal) to O-Matic liquid crystal (Np liquid crystal) having positive dielectric anisotropy is sealed. Furthermore, polarizing plates 16 and 1 are provided on the outer surface of each of the glass substrates 10 and 11.
The alignment films 24 and 25 are aligned so that the molecules of the liquid crystal 14 are arranged in an approximately 906 twisted arrangement.

As a result, when a voltage is applied to this first liquid crystal cell 20, the dark field changes to transmission.

- The second liquid crystal cell 21 has the same glass substrates 12 and 13 as the first liquid crystal cell 20, transparent 'II
It is provided with I poles 26 and 27, alignment films 2B and 29, and liquid crystal 15, and polarizing plates 18 and 19 are laminated on the outer surface of each of the glass substrates 12 and 13 (D) so as to form crossed Nicols.

In addition, the above-mentioned 1. Second liquid crystal cell 20°21K
j? The polarization axes of the polarizing plates 17 and 18 that are in contact with each other are equal. Therefore, one of the polarizing plates 17 and 18 that are in contact with each other in this way may be omitted.

To drive the liquid crystal optical shutter configured as described above, 14
As shown in FIG. 42 (5) and (b), voltages with opposite phases are applied. Accordingly, the first and second liquid crystal cells 20
．． The liquid crystal light shutter consisting of 21 alternately repeats a transmitting state and a light blocking state.

In this embodiment, as shown in FIG. 2 GA) and CB)! ! ! The amount of transmitted light when voltage is applied is shown in the same figure (Q
), the fall time in this case is 3 [
rnsec], thereby improving responsiveness.

Further, as another embodiment of the present invention, as shown in FIG. 3, polarizing plates 3G and 31.32 as described above may be sandwiched within a substrate 33.34.35 made of a transparent material. In this way, the step of bonding the polarizing plate can be omitted, the thickness can be reduced, and the performance of this type of liquid crystal optical shutter can be further improved.

The mode of each liquid crystal cell according to the present invention is not limited to the above-mentioned embodiments; for example, by applying a voltage, the mode changes from a dark field to a cloudy state, or from a cloudy state to a dark field. It may be a mode that changes the field of view.

Further, in each of the above embodiments, a polarizing plate was provided, but the present invention may be applied to an arrangement without a polarizing plate.

(Effects of the Invention) As is clear from the above description, according to the present invention, a light shutter effect with a steep response speed can be achieved in both cases of light transmission and blocking due to the application and non-application of voltage. Furthermore, the contrast can be improved by forming a multilayer structure.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of essential parts showing an embodiment according to the present invention;
Fig. M2 is a time chart showing the relationship between the driving voltage signal and the amount of transmitted light in the embodiment shown in Fig. 1, Fig. 3 is a schematic cross-sectional view of 9 parts showing another embodiment according to the present invention, and Fig. 4 is a schematic sectional view of the main part showing the conventional example, and M5Uy:J is II! of the conventional example shown in FIG. , is a diagram showing the relationship between the dual-use voltage signal and the amount of transmitted light. 10.11, 12, 13, 33, 34, 35...substrate (glass substrate). 14.15--LCD, 16.1? , 18, 19, 30, 31. 32 fist/fist polarizing plate, 2G, 21... liquid crystal cell, 22.23, 26.27... conductive film (on transparent electrode 24
．． 21.28.29...Alignment film. Patent applicant: Victor Company of Japan. Representative Shishi Michi Part', 0th block's width is 2nd figure, 8th figure

Claims (1)

[Scope of Claims] A plurality of liquid crystal cells each comprising a liquid crystal sealed between a pair of substrates facing each other with a predetermined interval and a conductive film laminated on each of the substrates and applying a voltage to the liquid crystal are stacked, A liquid crystal optical shutter characterized in that each liquid crystal cell has two or more modes determined by the alignment form of liquid crystal molecules and the combination of this alignment form and the polarization axis of a polarizing plate.