Aberration compensation in image projection displays

• US 6,536,907 B1
• Filed: 02/08/2000
• Issued: 03/25/2003
• Est. Priority Date: 02/08/2000
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Butterworth, Mark, Towner, David K.
• Primary Examiner(s): Adams, Russell
• Assistant Examiner(s): Koval, Melissa J
• Application Number:
  US09/499,707
• Time in Patent Office: 1,141 Days
• Field of Search: 348/745, 348/746, 348/747, 348/771, 348/806, 353/69, 353/70, 353/121, 396/115, 396/149, 396/150, 396/430
• US Class Current: 353/121
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• CPC Class Codes: H04N 9/28 Arrangements for convergence or focusing
• CPC Class Codes: H04N 9/3185 Geometric adjustment, e.g. keystone or convergence optical or mechanical adjustment of convergence H04N9/317; using scanning means H04N3/22; optical or mechanical adjustments of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/14

Abstract

Optical projection systems for the display of electronic images often suffer from degraded image quality due to color field registration errors caused by lateral chromatic aberration. Although most projection lenses are partially corrected for lateral chromatic aberration during the design process, the uncorrected residual aberration limits the imaging performance of many projection displays, especially when displaying text and graphics with single-pixel-wide features. Some embodiments of the invention correct color field registration errors due to lateral chromatic aberration in multiple-imager projection systems. Other embodiments of the invention correct radial distortion and keystone distortion in single-imager and multiple-imager projection displays. In some embodiments of the invention, the imager(s) pixel geometry is arranged to compensate for optical aberrations, which result from the optical system so as to achieve a corrected image.

Claims

1. An optical imaging system having an imager arranged for processing of imaging light from a light source, to an imaging optics device having at least one lens or concave mirror, the imager including an array of pixels in which the pixel geometry is arranged to compensate for aberration in the imaging optics to thereby provide corrected imaging.

2. An optical imaging system as claimed in claim 1, including a plurality of imagers which project or receive light of respective different colors through the same imaging optics device.

3. An optical imaging system as claimed in claim 2, wherein each of the imagers has a non-uniform pixel geometry which is arranged to compensate for at least one of radial distortion and keystone distortion aberrations.

4. An optical imaging system as claimed in claim 2, wherein the non-uniform pixel geometries of the imagers are arranged differently from each other to compensate for lateral chromatic aberration.

5. An optical imaging system as claimed in claim 3, wherein the non-uniform pixel geometries of the imagers are arranged differently from each other to compensate for lateral chromatic aberration.

6. An optical imaging system as claimed in claim 1, wherein the optical imaging system is an image projection display device.

7. An optical imaging system as claimed in claim 6 including a plurality of imagers in the form of image-forming devices, wherein a first imager produces a first image field in a first wavelength range and a second imager produces a second image field in a second wavelength range, the first imager having a different non-uniform pixel geometry than the second imager.

8. An optical imaging system as claimed in claim 7, further including a third imager which produces a third image field in a third wavelength range.

9. An optical imaging system as claimed in claim 8, the third imager having the same non-uniform pixel geometry as the first imager.

10. An optical imaging system as claimed in claim 1 including a plurality of imagers in the form of image-sensing devices, wherein a first imager is reactive to imaging light of a first image field in a first wavelength range and a second imager is reactive to imaging light of a second image field in a second wavelength range, the first imager having a different non-uniform pixel geometry than the second imager.

11. An optical imaging system as claimed in claim 10, further including a third imager which is reactive to imaging light of a third image field in a third wavelength range.

12. An optical imaging system as claimed in claim 11, the third imager having the same non-uniform pixel geometry as the first imager.

13. An imager for processing light in conjunction with imaging optics, the imager having a two-dimensional array of light-producing, light modifying or light-sensing pixels, wherein the array has a non-uniform geometry with the pixels arranged to compensate for an optical aberration of the imaging optics.

14. A pixelated imager as claimed in claim 13 wherein the non-uniform geometry of the pixel array comprises a difference in adjacent pixel spacing, the difference in pixel spacing being an integral number of photolithographic grid spacings.

15. A method for producing an imager for an image forming or image acquisition system which processes imaging light from a light source by respectively projecting or receiving through an imaging optics device, comprising the steps of:

selecting an optical imaging system configuration for use with an imager;

selecting or designing imaging optics for use with the imager in the selected configuration;

selecting a set of start points;

mapping a set of end points on the imager corresponding to images of the start points formed by said imaging optics;

designing a non-uniform pixel geometry for the imager using the mapping of said start points to said end points; and

producing an imager having said non-uniform pixel geometry.

16. A method as claimed in claim 15, wherein the mapping of said end points from said start points is accomplished by computerized ray tracing.

17. A method as claimed in claim 15, wherein the optical imaging system configuration further utilizes an image projection display having a projection screen, and wherein the selection of selected set of start points corresponds to a set of points on said projection screen.

18. A method as claimed in claim 17, wherein the mapping of the set of end points corresponds to a set of points in the plane of the imager, as traced from the selected set of start points on said projection screen, in use in the selected optical imaging system configuration.

19. A method as claimed in claim 18, wherein the mapping of said end points from said start points is accomplished by computerized ray tracing.

20. A method as claimed in claim 18, wherein said selection of the set of start points represents a set of desired pixel projection locations on said projection screen, and wherein said mapping of the set of end points represents said non-uniform pixel geometry for the imager, wherein said non-uniform pixel geometry is arranged to compensate for aberration in said imaging optics.