Optical row displacement for a fault tolerant projective display

• US 5,790,297 A
• Filed: 06/27/1997
• Issued: 08/04/1998
• Est. Priority Date: 06/26/1997
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Berlin, Andrew A.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US08/884,364
• Time in Patent Office: 403 Days
• Field of Search: 359/245, 359/259, 359/290, 359/291, 359/292, 359/295, 359/224, 345/84, 345/85, 348/770, 348/771
• US Class Current: 359/259
• CPC Class Codes: G09G 2330/08 Fault-tolerant or redundant circuits, or circuits in which repair of defects is prepared
• CPC Class Codes: G09G 3/001 using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• CPC Class Codes: G09G 3/007 Use of pixel shift techniques, e.g. by mechanical shift of the physical pixels or by optical shift of the perceived pixels
• CPC Class Codes: H04N 9/312 Driving therefor driving of electronic spatial light modulators in displays other than projection devices G09G3/34, G09G3/36; control of liquid crystal elements G02F1/133; control of micromechanical modulators G02B26/08
• CPC Class Codes: H04N 9/3182 Colour adjustment, e.g. white balance, shading or gamut white balance per se H04N9/73; control of amplitude of colour signals H04N9/68; colour control circuits for displays in general G09G5/02, G09G3/2003, G09G3/3607

Abstract

A projective display system includes a light source, a display surface, and a two dimensional light modulator array in an optical path between the light source and the display surface. The two dimensional light modulator array has a plurality of light modulators arranged in rows to modulate light from the light source, with at least one row being susceptible to failure. To compensate for any failed rows, an optical element redirects modulated light from presenting a first row of virtual pixels on the display surface to substantially occupy a second row of virtual pixels on the display surface. In conjunction with various image processing techniques for deblurring, this permits partial or complete correction for faulty rows of light modulators.

Claims

1. A display system comprising

a light source,

a display surface,

a two dimensional light modulator array having a plurality of light modulators arranged in a first row and a second row to modulate light from the light source, with light modulated by the first row presented as a first row of pixels on the display surface, and light modulated by the second row presented as a second row of pixels on the display surface, and

at least one optical element for redirecting first row modulated light from its presentation as the first row of pixels on the display surface to substantially occupy the second row of pixels on the display surface.

2. The display system of claim 1, wherein the at least one optical element further comprises a movable mirror.

3. The display system of claim 2, wherein the movable mirror is oscillated at greater than about a 10 Hz frequency.

4. The display system of claim 1, wherein the plurality of light modulators controllably transmit and absorb light.

5. The display system of claim 1, wherein the plurality of light modulators reflect light.

6. The display system of claim 1, wherein the two dimensional light modulator array further comprises a plurality of light modulators arranged in a first column and a second column to modulate light from the light source, with light modulated by the first column presented as a first row of column pixels on the display surface, and light modulated by the second column presented as a second row of column pixels on the display surface, and wherein

at least one optical element redirects first column modulated light from its presentation as the first column of pixels on the display surface to substantially occupy the second column of pixels on the display surface.

7. A fault tolerant display system comprising

a display surface for receiving a projected display,

a light source for producing a variable intensity light beam,

a two dimensional light modulator array positioned to intercept the variable intensity light beam from the light source and selectively redirect the variable intensity light beam toward the display surface, the two dimensional light modulator array having a plurality of light modulators arranged in a first row and a second row,

at least one optical element for redirecting first row modulated light from its presentation as the first row of pixels on the display surface to substantially occupy the second row of pixels on the display surface, and

a light modulator failure compensation system for correcting for failure of at least one of the plurality of light modulators, the light modulator failure compensation system having an image resealing module to reduce apparent light modulator display intensity, and a light source intensity control for increasing intensity of the variable intensity light beam.

8. The display system of claim 7, wherein the at least one optical element further comprises a movable mirror.

9. The display system of claim 7, wherein the plurality of light modulators controllably transmit and absorb light.

10. The display system of claim 7, wherein the plurality of light modulators reflect light.

11. The display system of claim 7, wherein the two dimensional light modulator array further comprises a plurality of light modulators arranged in a first column and a second column to modulate light from the light source, with light modulated by the first column presented as a first row of column pixels on the display surface, and light modulated by the second column presented as a second row of column pixels on the display surface, and wherein

at least one optical element redirects first column modulated light from its presentation as the first column of pixels on the display surface to substantially occupy the second column of pixels on the display surface.

12. A fault tolerant image display system comprising

a light modulator array having a plurality of light modulators for defining a first image,

an optical element for receiving the first image from the light modulator array to project a second image, with the optical element controlled to periodically displace the second image with a frequency exceeding about 1/10 of a second, and

a light modulator failure compensation system for correcting for failure of at least one of the plurality of light modulators, the light modulator failure compensation system having an image shifting module for redefining the first image in coordination with periodic displacement of the second image, and a resealing module to reduce apparent light modulator display intensity for at least some light modulators positioned adjacent to a failed light modulator.

13. The fault tolerant display system of claim 12, further comprising a variable intensity light source for increasing light intensity to compensate for reduced apparent light modulator display intensity.