The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 05, 1990
Filed:
Dec. 12, 1988
John N Cederquist, Ann Arbor, MI (US);
Environmental Research Institute of Michigan, Ann Arbor, MI (US);
Abstract
A method for producing multicolor holographic optical elements useful in presentation of multicolor holographic images in a head-up display (HUD) system. Because of restricted geometries, such HUDs should allow for reconstruction of wavefronts employing all readout beams coming from the same direction, with the reconstructed wavefront being cast in a specified direction. A first method for producing a multicolor HOE satisfying these conditions makes all recording at the same wavelength but with varying record geometries. A second method for producing multicolor HOEs employs the same record geometries but uses varying wavelengths of recording light. This allows the recording to be made under conditions where the diffraction efficiency of the resulting HOEs is controlled, as are the displayed colors. As the consequence of this, the multicolor HOE can be made under conditions which allow the Bragg condition to be satisfied for each of the readout wavelengths allowing a uniformly bright multicolor wavefront to be reconstructed. A third method for producing such HOEs is to further change the recording geometry by redirecting all the recording wavefronts through the same angular interval. This minimizes the crosstalk which occurs between images recorded at different wavelengths. Also disclosed are apparatus for display of each of the HOEs.