Light guide optical device

• US 7,576,916 B2
• Filed: 04/24/2007
• Issued: 08/18/2009
• Est. Priority Date: 03/21/2002
• Status: Active Grant

• Current Assignee: Lumus Ltd.
• Original Assignee: Lumus Ltd.
• Inventors: Amitai, Yaakov
• Primary Examiner(s): Ben; Loha
• Application Number:
  US11/789,220
• Publication Number:
  US 20080158685A1
• Time in Patent Office: 847 Days
• Field of Search: 359/618, 359/629, 359/630, 359/634, 359/636, 359/483, 359/485, 359/489, 359/490, 345 5- 9, 353/31, 353/33, 353/34, 353/37
• US Class Current: 359/618
• CPC Class Codes: G02B 2006/0098 for scanning
• CPC Class Codes: G02B 2027/0114 comprising dichroic elements
• CPC Class Codes: G02B 2027/012 comprising devices for attenuating parasitic image effects
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• 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 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0081 with means for altering, e.g. enlarging, the entrance or exit pupil
• 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 27/022 Viewing apparatus G02B27/04, G02B27/06, G02B27/08 take precedence
• CPC Class Codes: G02B 27/1073 characterized by manufacturing or alignment methods
• CPC Class Codes: G02B 27/108 for sampling a portion of a beam or combining a small beam in a larger one, e.g. wherein the area ratio or power ratio of the divided beams significantly differs from unity, without spectral selectivity
• CPC Class Codes: G02B 27/145 having sequential partially reflecting surfaces
• CPC Class Codes: G02B 27/148 including stacked surfaces having at least one double-pass partially reflecting surface
• CPC Class Codes: G02B 27/286 for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34
• CPC Class Codes: G02B 30/26 of the autostereoscopic type
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00
• CPC Class Codes: G02B 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/0028 : Light guide, e.g. taper
• CPC Class Codes: G02B 6/003 : Lens or lenticular sheet or layer
• CPC Class Codes: G02B 6/0055 : Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0056 : for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements

Abstract

The invention provides an optical device, including a light-transmitting substrate, optical means for coupling light into the substrate by total internal reflection, and a plurality of partially reflecting surfaces carried by the substrate, characterized in that the partially reflecting surfaces are parallel to each other and are not parallel to any of the edges of the substrate.

Claims

1. An optical device for partially reflecting a first set of light waves having a given polarization state and located within a given optical spectrum and within a first angular spectrum, and transmitting a second set of light waves having the same given polarization state and located within the same given optical spectrum and within a second angular spectrum, comprising:

a first light-transmitting substrate having a surface, and

a dichroic coating disposed on said surface,

characterized in that angles located within said first angular spectrum are smaller than angles located within said second angular spectrum and that the reflectivity by the coated surface of said first set of light waves is higher than the reflectivity by the coated surface of said second set of light waves.

2. The optical device according to claim 1, further comprising a second light-transmitting substrate optically coupled to the first light-transmitting substrate at said coated surface.

3. The optical device according to claim 1, wherein said polarization state is the P-polarization.

4. The optical device according to claim 1, wherein said polarization state is a combination of the S and the P polarizations.

5. The optical device according to claim 4, wherein the reflectance of said first set of light waves decreases monotonically with increasing incident angles at said surface.

6. The optical device according to claim 1, wherein the reflectance of said first set of light waves changes monotonically with increasing incident angles at said surface.

7. The optical device according of claim 6, wherein the reflectance of said first set of light waves increases monotonically with increasing incident angles at said surface.

8. The optical device according to claim 1, wherein said optical spectrum is located within the visual spectrum.

9. The optical device according to claim 1, wherein said optical spectrum is located within the region between 460 nm and 640 nm.

10. The optical device according to claim 1, wherein said first angular spectrum is located within the region between 15°

and 40°

.

11. The optical device according to claim 1, wherein said second angular spectrum is located within the region between 50°

and 80°

.

12. The optical device according to claim 1, wherein a specific minimal reflectance is set for said first angular spectrum.

13. The optical device according to claim 12, wherein the reflectivity by said coated surface of said first set of light waves is higher than said specific minimal reflectance.

14. The optical device according to claim 12, wherein the reflectivity of said specific minimal reflectance is higher than 20%.

15. The optical device according to claim 1, wherein a specific maximal reflectance is set for said second angular spectrum.

16. The optical device according to claim 15, wherein the reflectivity by said coated surface of said second set of light waves is lower than said specific maximal reflectance.

17. The optical device according to claim 15, wherein the reflectivity of said specific maximal reflectance is lower than 10%.