Claims
- 1. A driving apparatus for a photoconductive liquid crystal light valve having a liquid crystal layer, a photoconductive layer and two electrodes arranged to sandwich said liquid crystal layer and photoconductive layer and designed to allow a writing light to be incident upon said photoconductive layer by light writing means coupled to a writing side, said driving apparatus comprising:
- means for applying a drive voltage signal from a drive voltage source across said two electrodes; and
- detection means for detecting an impedance across said two electrodes for use in adjusting a luminous intensity of the writing light.
- 2. The driving apparatus according to claim 1, wherein said detection means comprises an impedance element provided between said drive voltage source and one of said two electrodes and detects a voltage drop of said impedance element.
- 3. The driving apparatus according to claim 1, wherein said detection means comprises a bridge circuit having two input terminals and two output terminals, having a node between one of said two electrodes and one end of a first impedance element as one input terminal, having a node between the other end of said first impedance element and one end of a second impedance element as one output terminal, having a node between the other end of said second impedance element and one end of a third impedance element as the other input terminal, having a node between the other end of said third impedance element and the other one of said electrodes as the other output terminal, whereby said drive voltage signal is supplied across said two input terminals, and detects a voltage across said two output terminals.
- 4. The driving apparatus according to claim 3, wherein impedances of said second and third impedance elements are set equal to each other, and an impedance of individual layers excluding said photoconductive layer of said photoconductive liquid crystal light valve is set equal to that of said first impedance element.
- 5. A photoconductive liquid crystal light valve display apparatus comprising:
- a photoconductive liquid crystal light valve having a liquid crystal layer, a photoconductive layer and two electrodes arranged to sandwich said liquid crystal layer and photoconductive layer;
- video signal amplifying means for amplifying an input video signal and outputting an output video signal;
- light writing means, coupled to a writing side of said photoconductive liquid crystal light valve, for allowing a writing light corresponding to said output video signal to be incident upon said photoconductive layer;
- drive means for applying a drive voltage signal across said two electrodes;
- writing light intensity detection means for detecting an impedance across said two electrodes;
- adjusting video signal generating means for generating an adjusting video signal having a white level and a black level;
- selective supply means for supplying said adjusting video signal as an input video signal to said video signal amplifying means;
- comparing means for comparing levels of detection outputs of said writing light intensity detection means at times of generation of respectively said adjusting video signal of said white level and said adjusting video signal of said black level with reference levels corresponding to said white and black levels; and
- means for changing offset and gain of said video signal amplifying means in accordance with comparison outputs of said comparing means.
- 6. A driving and adjusting apparatus for a photoconductive liquid crystal light valve having a liquid crystal layer, a photoconductive layer and two electrodes arranged to sandwich said liquid crystal layer and photoconductive layer and designed to allow a writing light to be incident upon said photoconductive layer by light writing means coupled to a writing side, said drive and adjusting apparatus comprising:
- means for applying a drive voltage signal from a drive voltage source across said two electrodes;
- detection means for detecting an impedance across said two electrodes and outputting a detected writing light intensity signal corresponding to the detected impedance; and
- adjusting means for adjusting a luminous intensity of the writing light in response to the detected writing light intensity signal.
- 7. The driving apparatus according to claim 6, wherein said detection means comprises an impedance element provided between said drive voltage source and one of said two electrodes and detects a voltage drop of said impedance element.
Priority Claims (2)
Number |
Date |
Country |
Kind |
4-041345 |
Feb 1992 |
JPX |
|
4-091013 |
Apr 1992 |
JPX |
|
Parent Case Info
This application is a continuation of U.S. patent application Ser. No. 08/008,935, filed Jan. 26, 1993, now abandoned.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
3936640 |
Haas et al. |
Feb 1976 |
|
4205311 |
Kutaraga |
May 1980 |
|
5009490 |
Kouno et al. |
Apr 1991 |
|
Continuations (1)
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Number |
Date |
Country |
Parent |
8935 |
Jan 1993 |
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