Optical display device

• US 7,751,662 B2
• Filed: 01/22/2009
• Issued: 07/06/2010
• Est. Priority Date: 01/24/2008
• Status: Active Grant

• Current Assignee: CARL Zeiss JENA GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: Carl Zeiss AG (Carl-Zeiss-Stiftung)
• Inventors: Kleemann, Bernd
• Primary Examiner(s): Pak; Sung H
• Application Number:
  US12/358,034
• Publication Number:
  US 20090245730A1
• Time in Patent Office: 530 Days
• Field of Search: 385/37
• US Class Current: 385/37
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/0136 with a single image source for both eyes
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/4272 having plural diffractive elements positioned sequentially along the optical path
• CPC Class Codes: G02B 5/1861 Reflection gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence
• CPC Class Codes: G02B 5/1866 Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence

Abstract

An optical display device, in particular for use in a head-up display or a head-mounted display, comprises an essentially planar light guide, an image-generating system, a first diffraction grating by which light that comes from the image-generating system can be coupled into the light guide, and a second diffraction grating, by which the light can be coupled out again from the light guide. At least one of the two diffraction gratings is a binary-blazed grating having a multiplicity of diffraction structures, which are composed of a multiplicity of individual substructures that ensure a blaze effect and in plan view have the shape of a closed geometrical surface.

Claims

1. An optical display device comprising:

a) an essentially planar light guide;

b) an image-generating system;

c) a first diffraction grating by which light that comes from the image-generating system can be coupled into the light guide; and

d) a second diffraction grating by which the light can be coupled out again from the light guide;

wherein

e) at least one of the two diffraction gratings is a binary-blazed grating having a multiplicity of diffraction structures, which

essentially extend mutually parallel,

have a width g perpendicular to their lengthwise direction which is greater than the effective wavelength of the light that comes from the image-generating system, and

are composed of a multiplicity of individual substructures that ensure a blaze effect and have a maximum dimension p in the lengthwise direction of the diffraction structures which at least on average over a diffraction structure is less than the wavelength of the light, and

wherein the diffraction structures respectively include a row of individual substructures along a lengthwise direction, which in plan view have the shape of a closed geometrical surface whose dimension directed parallel to the lengthwise direction of the diffraction structures varies in a direction perpendicular to the lengthwise direction of the diffraction structures, and which have a maximum dimension in the direction perpendicular to the lengthwise direction of the diffraction structures, which is greater than the wavelength of the light.

2. An optical display device according to claim 1, wherein the individual substructures vary from one diffraction structure to another diffraction structure so that their shape, their maximum dimension p in the lengthwise direction of the diffraction structures and/or their spacing along the lengthwise direction of the diffraction structures varies.

3. An optical display device according to claim 2, wherein between one diffraction structure and another diffraction structure, the maximum dimension p of the individual substructures in the lengthwise direction of the diffraction structures decreases to the extent that their spacing along the lengthwise direction of the diffraction structures increases.

4. An optical display device according to claim 1, wherein the individual substructures have different profile depths from one diffraction structure to another.

5. An optical display device according to claim 1, wherein the individual substructures, of which the diffraction structures are composed, all have the same height h.

6. An optical display device according to claim 1, wherein the optical display device is part of a head-mounted display.

7. An optical display device according to claim 1, wherein the optical display device is part of a head-up display.