Method of color correction in a color video display system

• US 6,008,939 A
• Filed: 02/01/1999
• Issued: 12/28/1999
• Est. Priority Date: 04/06/1998
• Status: Expired due to Term

• Current Assignee: Sherwood Partners Incorporated, Stryker Corporation
• Original Assignee: Optimize, Inc.
• Inventors: Hebert, Raymond T.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US09/241,828
• Time in Patent Office: 330 Days
• Field of Search: 359/475, 359/472, 359/466, 359/558, 359/559, 359/482, 359/13, 345/8
• US Class Current: 359/475
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/0116 comprising devices for correcting chromatic aberration
• CPC Class Codes: G02B 2027/0132 comprising binocular systems
• CPC Class Codes: G02B 2027/0136 with a single image source for both eyes
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 3/002 to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT
• CPC Class Codes: G09G 3/003 to produce spatial visual effects

Abstract

Low-cost complex plastic optics allow biocular viewing of video images generated by a single electro-optic display device, such as in a head-mounted display (HMD) for commercial or medical viewing applications. A dual off-axis configuration uses nearly collimated illumination optics and intermediate imaging optics to fill both eyepieces from a single display device without the need for a beamsplitter. Multiple illumination schemes are provided for either monochrome or color, and in either two-dimensional or time-sequential true stereographic presentation. Light from multicolor sources is superimposed, mixed, and homogenized by mixing light cones with diffractive collectors. Offsetting color overcorrection and undercorrection of individual optical elements achieves overall chromatic correction with minimal optical element complexity.

Claims

1. A method of color correction in a color video display viewing system, comprising:

collecting and collimating colored light from a substantial point source into a substantially collimated beam using a collimating lens;

illuminating an image display surface with said substantially collimated beam;

converging said collimated beam to form an intermediate image of said display surface at an intermediate image plane using an imaging element, wherein said converged beam passes through a plane of minimum convergence between said imaging element and said intermediate image plane and wherein an image of said substantial point source is formed at said plane of minimum convergence;

forming a virtual image of said intermediate image plane using an eyepiece lens;

wherein said collimating lens is color undercorrected and said imaging element is color overcorrected to offset said color undercorrected collimating lens, such that said image at said plane of minimum convergence is color corrected.

2. A method of color correction in a color video display viewing system, comprising:

collecting and collimating colored light from a substantial point source into a substantially collimated beam using a collimating lens;

illuminating an image display surface with said substantially collimated beam;

converging said collimated beam to form an intermediate image of said display surface at an intermediate image plane using an imaging element, wherein said converged beam passes through a transform plane located between said imaging element and said intermediate image plane and wherein an image of said substantial point source is formed at said transform plane; and

forming a virtual image of said intermediate image plane using an eyepiece lens, wherein said imaging element is color overcorrected and said eyepiece lens is substantially undercorrected, such that said virtual image is color corrected.

3. The method according to claim 2, wherein said imaging element is color overcorrected and said collimating lens is color undercorrected to offset said color overcorrected imaging element, such that said image at said transform plane is color corrected.