Optical transmittance adjusting device having a matrix of electrodes each connected to a photoconductor smaller than the electrode

• US 5,657,100 A
• Filed: 01/27/1995
• Issued: 08/12/1997
• Est. Priority Date: 02/03/1992
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ishii, Yutaka, Yamamoto, Yoshitaka
• Primary Examiner(s): GROSS, ANITA P
• Application Number:
  US08/380,249
• Time in Patent Office: 928 Days
• Field of Search: 359/72, 349/41, 349/1
• US Class Current: 349/41
• CPC Class Codes: G02F 1/135 Liquid crystal cells structurally associated with a photoconducting or a ferro-electric layer, the properties of which can be optically or electrically varied G02F1/133348 takes precedence
• CPC Class Codes: G03B 27/735 in dependence upon automatic analysis of the original

Abstract

An optical transmittance adjusting device which includes an optical transmittance adjusting plane divided into a plurality of areas; and adjusting means for detecting an amount of light incident on each of the areas and adjusting an optical transmittance separately for each of the areas based on the detected amount of light.

Claims

1. A contrast ratio adjusting device, comprising:

a liquid crystal; and

a first substrate and a second substrate interposing the liquid crystal therebetween,

wherein

the first substrate includes a first transparent electrode adjacent to the liquid crystal, and

the second substrate includes a matrix of second transparent electrodes, each of which is connected to a respective transparent photoconductor, an area occupied by each photoconductor being smaller than that of its connected second transparent electrode, the second transparent electrodes and the transparent photoconductors being on the liquid crystal side of the second substrate, the first electrode and the second electrodes being supplied with an AC voltage.

2. A contrast ratio adjusting device according to claim 1, wherein the liquid crystal is formed of a material having a positive dielectric anisotropy.

3. A contrast ratio adjusting device according to claim 1, wherein the liquid crystal is formed of a material having a negative dielectric anisotropy.

4. A display apparatus comprising:

a display device, and

a contrast ratio adjusting means comprising a contrast ratio adjusting plane divided into a plurality of areas, and

adjusting means for detecting an amount of light incident on each of the areas and adjusting a contrast ratio by varying an optical transmittance separately for each of the areas, based on the detected amount of light incident on each of the areas,

wherein the adjusting means comprises a respective photoconductor for detecting the amount of light incident on each of the areas, an area occupied by each photoconductor being smaller than that of its respective area of said plane.

5. A display apparatus according to claim 4, further comprising a pair of polarizers sandwiching the display device therebetween.

6. A color plate making apparatus comprising:

a light source for emitting light to an object;

a light dividing means for dividing light, reflected from the object, into a plurality of color components;

a plate making data forming means for converting the plurality of color components into plate making data to be controlled; and

a contrast ratio adjusting means provided between the document and the plate making data forming means, the contrast ratio adjusting means comprising a contrast ratio adjusting plane divided into a plurality of areas, and adjusting means for detecting an amount of light incident on each of the areas and adjusting a contrast ratio by varying an optical transmittance separately for each of the areas, based on the detected amount of light incident on each of the areas,

wherein the adjusting means comprises a respective photoconductor for detecting the amount of light incident on each of the areas, an area occupied by each photoconductor being smaller than that of its respective area of said plane.

7. A color plate making apparatus according to claim 6, wherein the contrast ratio adjusting means is provided between the document and the light dividing means.

8. A color plate making apparatus according to claim 6, wherein the contrast ratio adjusting means is provided between the light dividing means and the plate making data forming means.

9. A color copying apparatus comprising:

a color component making means for making a plurality of color components in accordance with an image of a document;

an image reproducing means for reproducing an image based on the plurality of color components; and

a contrast ratio adjusting means provided between the document and the image reproducing means, the contrast ratio adjusting means comprising a contrast ratio adjusting plane divided into a plurality of areas, and adjusting means for detecting an amount of light incident on each of the areas and adjusting a contrast ratio by varying an optical transmittance separately for each of the areas based on the detected amount of light incident on each of the areas,

wherein the adjusting means comprises a respective photoconductor for detecting the amount of light incident on each of the areas, an area occupied by each photoconductor being smaller than that of its respective area of said plane.

10. A color facsimile apparatus comprising:

a sensor means for reading an image of a document as a plurality of color components; and

a contrast ratio adjusting means provided between the document and the sensor means, the contrast ratio adjusting means comprising a contrast ratio adjusting plane divided into a plurality of areas, and adjusting means for detecting an amount of light incident on each of the areas and adjusting a contrast ratio by varying an optical transmittance separately for each of the areas based on the detected amount of light incident on each of the areas,

wherein the adjusting means comprises a respective photoconductor for detecting the amount of light incident on each of the areas, an area occupied by each photoconductor being smaller than that of its respective area of said plane.

11. A contrast adjusting device comprising:

first and second substrates facing each other;

a transparent uniform electrode formed on the first substrate;

a plurality of pixel electrodes formed in rows and in columns along source electrodes on the second substrate, each of the pixel electrodes overlapping a corresponding one of the source electrodes;

a plurality of photoconductors for electrically connecting the pixel electrodes to the respective source electrodes, each of the photoconductors being disposed in a region where a corresponding one of the pixel electrodes overlaps a corresponding one of the source electrodes; and

an adjusting layer interposed between the pixel electrodes and the uniform electrode, the adjusting layer having variable optical transmittance which is varied in accordance with a voltage applied between the pixel electrodes and the uniform electrode,

wherein light enters and travels across the second substrate toward the plurality of photoconductors.

12. A contrast adjusting device according to claim 11, wherein the photoconductors have a narrower width than that of the source electrodes.

13. A contrast adjusting device according to claim 11, wherein the adjusting layer includes a liquid crystal material having a positive dielectric anisotropy.

14. A contrast adjusting device according to claim 11, wherein the adjusting layer includes a liquid crystal material having a negative dielectric anisotropy.