Holographic optical devices

• US 6,580,529 B1
• Filed: 12/15/2000
• Issued: 06/17/2003
• Est. Priority Date: 04/02/1998
• Status: Expired due to Term

• Current Assignee: Elbit Systems Electro-Optics ELOP Limited (Elbit Systems Limited)
• Original Assignee: ELOP Electro-Optics Industries Limited, Yeda Research and Development Co. Ltd. (Weizmann Institute of Science)
• Inventors: Amitai, Yaakov, Friesem, Asher
• Primary Examiner(s): Juba, Jr., John
• Application Number:
  US09/647,520
• Time in Patent Office: 914 Days
• Field of Search: 359/13, 359/14, 359/15, 359/16, 359/19, 359/33, 359/34, 359/25, 359/32, 359/9, 385/37, 385/129
• US Class Current: 359/13
• CPC Class Codes: G02B 27/0081 with means for altering, e.g. enlarging, the entrance or exit pupil
• CPC Class Codes: G02B 27/0944 Diffractive optical elements, e.g. gratings, holograms gratings per se G02B5/18; holograms used as optical elements per se G02B5/32
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G03H 1/0408 Total internal reflection [TIR] holograms, e.g. edge lit or substrate mode holograms
• CPC Class Codes: G03H 1/2249 Holobject properties
• CPC Class Codes: G03H 1/2286 Particular reconstruction light G03H1/24 takes precedence; Beam properties
• CPC Class Codes: G03H 2001/2226 Edge lit holograms TIR recording G03H1/0408
• CPC Class Codes: G03H 2001/226 Virtual or real
• CPC Class Codes: G03H 2001/261 in optical contact
• CPC Class Codes: G03H 2001/264 One hologram being a HOE
• CPC Class Codes: G03H 2210/30 3D object

Abstract

The invention provides a holographic optical device, including a light-transmissive substrate; a first holographic optical element carried by the substrate; at least one second holographic optical element carried by the substrate laterally of the first holographic optical element, and at least one third holographic optical element carried by the substrate laterally displaced from the first and second holographic optical elements; wherein the center of at least one of the first, second or third holographic optical elements is located outside a single, straight line.

Claims

1. A holographic optical device, comprising:

a light-transmissive substrate having two opposite major surfaces parallel to the major plane of the substrate;

a first holographic optical element having a first area carried by said substrate for coupling optical waves from a light source and propagating them inside said substrate by total internal reflection;

at least one second holographic optical element having a second area carried by said substrate and being laterally displaced along the major plane of the substrate, from said first holographic optical element for changing the projection on substrate plane of the propagation directions of said optical waves, and

at least one third holographic optical element having a third area carried by said substrate and being laterally displaced along the major plane of the substrate from said first and second holographic elements for coupling the optical waves out of said substrate;

wherein the projection of the grating vectors of said first, second and third holographic optical elements on the major surface of the substrate are oriented along three different directions, and

wherein at least one of the lateral active areas of said third holographic optical element is larger than the lateral active area of said first holographic optical element.

2. The device according to claim 1, wherein at least one of said holographic optical elements is embodied in said substrate by recording said elements as an interference pattern of two mutually coherent optical waves.

3. The device according to claim 1, wherein at least one of said holographic optical elements is embodied in said substrate by means of computer-generated masks and lithographic techniques, or by direct writing techniques.

4. The device according to claim 1, wherein said first holographic optical element and said third holographic optical element are located on the same major surface of the substrate.

5. The device according to claim 1, wherein said first holographic optical element is located on one major surface of said substrate and said third holographic optical element is located on another major surface of said substrate.

6. The device according to claim 1, wherein said first holographic optical element has optical power utilizable as a collimating lens.

7. The device according to claim 1, wherein said first holographic optical elements diffracts trapped optical waves into a direction calculated to reach the eye of an observer.

8. The device according to claim 1, wherein said third holographic optical element is a display hologram illuminated by internally reflected light from said first and second holographic optical elements, so as to construct a three-dimensional image.

9. The device according to claim 1, wherein the diffraction efficiencies of said holographic optical elements vary locally for achieving output waves with uniform intensities.

10. The device according to claim 1, wherein the diffraction efficiencies of said holographic optical elements vary locally in order to achieve output waves with predefined intensities.