Transparency viewing device comprising passive matrix LCD

• US 5,835,173 A
• Filed: 05/28/1996
• Issued: 11/10/1998
• Est. Priority Date: 11/28/1993
• Status: Expired due to Fees

• Current Assignee: Smartlight Ltd.
• Original Assignee: Smartlight Ltd.
• Inventors: Inbar, Dan, Wolf, Hanan, Levi, Benzion
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): DUDEK, JAMES A
• Application Number:
  US08/654,277
• Time in Patent Office: 896 Days
• Field of Search: 349/61, 40/361, 40/363, 345/102, 345/77
• US Class Current: 349/61
• CPC Class Codes: G02B 27/026 and a display device, e.g. CRT, LCD, for adding markings or signs or to enhance the contrast of the viewed object
• CPC Class Codes: G02F 1/13306 Circuit arrangements or driving methods for the control of single liquid crystal cells G02F1/132, G02F1/133382 take precedence
• CPC Class Codes: G02F 1/13318 Circuits comprising a photodetector
• CPC Class Codes: G02F 1/13336 Combining plural substrates to produce large-area displays, e.g. tiled displays

Abstract

A transparency viewing device including a faceplate adapted for mounting at least one transparency thereon, an LCD array having a given chromaticity underlying the faceplate, a source of backlighting for the LCD array having a variable chromaticity and a controller which controls the chromaticity of the backlighting source based on the chromaticity of the light passing through the film and the LCA.

Claims

1. A transparency viewing device comprising:

a faceplate adapted for mounting at least one transparency thereon;

an LCD array having a given chromaticity underlying the faceplate;

a source of backlighting for the LCD array having a variable chromaticity; and

a controller which controls the chromaticity of the backlighting source based on the chromaticity of the light passing through the film and the LCD array.

2. A transparency viewing device according to claim 1 and comprising:

a sensor which views the faceplate and the transparency thereon and generates a chromaticity signal based on the light which passes through the LCD array and the film,

wherein the controller controls the chromaticity of the backlighting source responsive to the chromaticity signal.

3. A transparency viewing device according to claim 1 wherein the source of backlighting comprises a plurality of lighting sources having different chromaticities and wherein the controller controls the chromaticity by varying the relative intensities of the lighting sources having different chromaticities.

4. A transparency viewing device according to claim 2 wherein the source of backlighting comprises a plurality of lighting sources having different chromaticities and wherein the controller controls the chromaticity by varying the relative intensities of the lighting sources having different chromaticities.

5. A transparency viewing device according to claim 1 wherein the LCD array defines an array of pixels, wherein the LCD is substantially effective to block light within a relatively limited range of angles around the normal to the LCD in a light blocking mode and is relatively ineffective to block light reaching it from angles outside the limited range of angles and further comprising:

a light detector which views the array from an angle outside the range of angles at which the LCD is substantially effective to block the light in the light blocking mode.

6. A transparency viewing device according to claim 5 wherein the source of backlighting comprises:

a light source; and

a brightness enhancing, BE, device situated between the light source and the LCD array, which accepts light at a relatively large angle from the normal to the LC device and which transmits the major portion of the accepted light through a relatively limited angle around the normal to the LCD array for which the LCD is substantially effective to selectively block the light and a lesser portion of the light at a range of angles relatively far from the normal at which the LCD is not effective to block the light.

7. A transparency viewing device according to claim 5 in which the detector is a camera.

8. A transparency viewing device according to claim 6 in which the detector is a camera.

9. A transparency viewing device according to claim 2 wherein the LCD array defines an array of pixels, wherein the LCD is substantially effective to effectively block light within a relatively limited range of angles around the normal to the LCD in a light blocking mode and is relatively ineffective to block light reaching it from angles outside the limited range of angles and further comprising:

a light detector which views the array from an angle outside the range of angles at which the LCD is substantially effective to block the light in the light blocking mode.

10. A transparency viewing device according to claim 9 wherein the source of backlighting comprises:

a light source; and

a brightness enhancing, BE, device situated between the light source and the LCD array, which accepts light at a relatively large angle from the normal to the LC device and which transmits the major portion of the accepted light through a relatively limited angle around the normal to the LCD array for which the LCD is substantially effective to selectively block the light and a lesser portion of the light at a range of angles relatively far from the normal at which the LCD is not effective to block the light.

11. A transparency viewing device according to claim 9 in which the detector is a camera.

12. A transparency viewing device according to claim 3 wherein the LCD array defines an array of pixels, wherein the LCD is substantially effective to effectively block light within a relatively limited range of angles around the normal to the LCD in a light blocking mode and is relatively ineffective to block light reaching it from angles outside the limited range of angles and further comprising:

a light detector which views the array from an angle outside the range of angles at which the LCD is substantially effective to block the light in the light blocking mode.

13. A transparency viewing device according to claim 12 wherein the source of backlighting comprises:

a light source; and

a brightness enhancing, BE, device situated between the light source and the LCD array, which accepts light at a relatively large angle from the normal to the LC device and which transmits the major portion of the accepted light through a relatively limited angle around the normal to the LCD array for which the LCD is substantially effective to selectively block the light and a lesser portion of the light at a range of angles relatively far from the normal at which the LCD is not effective to block the light.

14. A transparency viewing device according to claim 12 in which the detector is a camera.

15. A transparency viewing device according to claim 4 wherein the LCD array defines an array of pixels, wherein the LCD is substantially effective to effectively block light within a relatively limited range of angles around the normal to the LCD in a light blocking mode and is relatively ineffective to block light reaching it from angles outside the limited range of angles and further comprising:

a light detector which views the array from an angle outside the range of angles at which the LCD is substantially effective to block the light in the light blocking mode.

16. A transparency viewing device according to claim 15 wherein the source of backlighting comprises:

a light source; and

a brightness enhancing, BE, device situated between the light source and the LCD array, which accepts light at a relatively large angle from the normal to the LC device and which transmits the major portion of the accepted light through a relatively limited angle around the normal to the LCD array for which the LCD is substantially effective to selectively block the light and a lesser portion of the light at a range of angles relatively far from the normal at which the LCD is not effective to block the light.

17. A transparency viewing device according to claim 15 in which the detector is a camera.

18. A transparency viewing device according to claim 1 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

a driver which identically electrifies a plurality of row electrodes which drive identical patterns of pixels, and which identically electrifies a plurality of column electrodes which drive identical patterns of pixels, wherein each of said patterns of pixels includes at least one pixel which is to be activated and wherein at least some of the plurality of row electrodes and some of the plurality of column electrodes are not contiguous.

19. A transparency viewing device according to claim 1 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

a driver which identically electrifies, using a non-scanning mode, those row electrodes which drive identical patterns of pixels, and which identically electrifies, using a non-scanning mode, those column electrodes which drive identical patterns of pixels.

20. A transparency viewing device according to claim 1 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

a driver which identically electrifies at least one row electrode and one at least one column electrode resulting in an effective null RMS voltage across at least one pixel element.

21. A transparency viewing device according to claim 2 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

a driver which identically electrifies a plurality of row electrodes which drive identical patterns of pixels, and which identically electrifies a plurality of column electrodes which drive identical patterns of pixels, wherein each of said patterns of pixels includes at least one pixel which is to be activated and wherein at least some of the plurality of row electrodes and some of the plurality of column electrodes are not contiguous.

22. A transparency viewing device according to claim 2 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

a driver which identically electrifies, using a non-scanning mode, those row electrodes which drive identical patterns of pixels, and which identically electrifies, using a non-scanning mode, those column electrodes which drive identical patterns of pixels.

23. A transparency viewing device according to claim 2 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

a driver which identically electrifies at least one row electrode and one at least one column electrode resulting in an effective null RMS voltage across at least one pixel element.

24. A transparency viewing device according to claim 3 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

a driver which identically electrifies a plurality of row electrodes which drive identical patterns of pixels, and which identically electrifies a plurality of column electrodes which drive identical patterns of pixels, wherein each of said patterns of pixels includes at least one pixel which is to be activated and wherein at least some of the plurality of row electrodes and some of the plurality of column electrodes are not contiguous.

25. A transparency viewing device according to claim 3 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

a driver which identically electrifies, using a non-scanning mode, those row electrodes which drive identical patterns of pixels, and which identically electrifies, using a non-scanning mode, those column electrodes which drive identical patterns of pixels.

26. A transparency viewing device according to claim 3 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

a driver which identically electrifies at least one row electrode and one at least one column electrode resulting in an effective null RMS voltage across at least one pixel element.

27. A transparency viewing device according to claim 4 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

a driver which identically electrifies a plurality of row electrodes which drive identical patterns of pixels, and which identically electrifies a plurality of column electrodes which drive identical patterns of pixels, wherein each of said patterns of pixels includes at least one pixel which is to be activated and wherein at least some of the plurality of row electrodes and some of the plurality of column electrodes are not contiguous.

28. A transparency viewing device according to claim 4 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

a driver which identically electrifies, using a non-scanning mode, those row electrodes which drive identical patterns of pixels, and which identically electrifies, using a non-scanning mode, those column electrodes which drive identical patterns of pixels.

29. A transparency viewing device according to claim 4 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

a driver which identically electrifies at least one row electrode and one at least one column electrode resulting in an effective null RMS voltage across at least one pixel element.

30. A transparency viewing device according to claim 5 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

wherein the driver identically electrifies a plurality of row electrodes which drive identical patterns of pixels, and identically electrifies a plurality of column electrodes which drive identical patterns of pixels, wherein each of said patterns of pixels includes at least one pixel which is to be activated and wherein at least some of the plurality of row electrodes and some of the plurality of column electrodes are not contiguous.

31. A transparency viewing device according to claim 5 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

wherein the driver identically electrifies, using a non-scanning mode, those row electrodes which drive identical patterns of pixels, and identically electrifies, using a non-scanning mode, those column electrodes which drive identical patterns of pixels.

32. A transparency viewing device according to claim 5 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

wherein the driver identically electrifies at least one row electrode and one at least one column electrode resulting in an effective null RMS voltage across at least one pixel element.

33. A transparency viewing device according to claim 6 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

wherein the driver identically electrifies a plurality of row electrodes which drive identical patterns of pixels, and identically electrifies a plurality of column electrodes which drive identical patterns of pixels, wherein each of said patterns of pixels includes at least one pixel which is to be activated and wherein at least some of the plurality of row electrodes and some of the plurality of column electrodes are not contiguous.

34. A transparency viewing device according to claim 6 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

wherein the driver identically electrifies, using a non-scanning mode, those row electrodes which drive identical patterns of pixels, and identically electrifies, using a non-scanning mode, those column electrodes which drive identical patterns of pixels.

35. A transparency viewing device according to claim 6 wherein the LCD array comprises:

a passive matrix LCD array situated intermediate the source of back lighting and the faceplate and comprising a plurality, N, of row electrodes and a plurality, M, of column electrodes separated by liquid crystal material, wherein the intersections of the row and column electrodes define a matrix of N×

M pixel elements arranged in N rows and M columns, which pixels can be excited by a voltage difference between the two electrodes intersecting a pixel; and

wherein the driver identically electrifies at least one row electrode and one at least one column electrode resulting in an effective null RMS voltage across at least one pixel element.

36. A transparency viewing device in accordance with claim 5 wherein the light detector acquires an image of the faceplate with the LCD array in a light blocking mode and including a processor which determines the extent of a transparency mounted on the viewing surface from said image.

37. A transparency viewing device in accordance with claim 5 wherein the light detector acquires an image of the faceplate with the LCD array in a light blocking mode and including a processor which determines the extent of an image on a transparency mounted on the viewing surface from said image.

38. A transparency viewing device in accordance with claim 9 wherein the light detector acquires an image of the faceplate with the LCD array in a light blocking mode and including a processor which determines the extent of a transparency mounted on the viewing surface from said image.

39. A transparency viewing device in accordance with claim 9 wherein the light detector acquires an image of the faceplate with the LCD array in a light blocking mode and including a processor which determines the extent of an image on a transparency mounted on the viewing surface from said image.

40. A transparency viewing device in accordance with claim 12 wherein the light detector acquires an image of the faceplate with the LCD array in a light blocking mode and including a processor which determines the extent of a transparency mounted on the viewing surface from said image.

41. A transparency viewing device in accordance with claim 12 wherein the light detector acquires an image of the faceplate with the LCD array in a light blocking mode and including a processor which determines the extent of an image on a transparency mounted on the viewing surface from said image.

42. A transparency viewing device in accordance with claim 15 wherein the light detector acquires an image of the faceplate with the LCD array in a light blocking mode and including a processor which determines the extent of a transparency mounted on the viewing surface from said image.

43. A transparency viewing device in accordance with claim 15 wherein the light detector acquires an image of the faceplate with the LCD array in a light blocking mode and including a processor which determines the extent of an image on a transparency mounted on the viewing surface from said image.

44. A method of viewing a transparency comprising:

backlighting an LCD array on which a transparancy is to be mounted, for viewing with a source of backlighting having a variable chromaticity; and

controling the chromaticity of the backlighting source based on the chromaticity of the LCD array and the transparancy.