Optical Relay for Compact Head Up Display

• US 20100053753A1
• Filed: 06/24/2009
• Published: 03/04/2010
• Est. Priority Date: 08/26/2008
• Status: Active Grant

• Current Assignee: Microvision, Inc.
• Original Assignee: Microvision, Inc.
• Inventors: Nestorovic, Nenad, Hegland, Joel E.
• Granted Patent: US 7,854,523 B2
• Time in Patent Office: Days
• US Class Current: 359/493
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/012 comprising devices for attenuating parasitic image effects
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• CPC Class Codes: G02B 2027/0127 comprising devices increasing the depth of field
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/28 for polarising used in stereoscopes G02B30/25

Abstract

An optical relay (500) includes a glare trap (512) that in one embodiment has one or more surfaces configured to reflect light impinging the surface (550) at an angle less than a first angle (722) relative to a normal line (710), and to transmit light impinging the surface (550) at an angle greater than a second angle (723) relative to the normal line (710). In other embodiments, the glare trap (512) reflects light impinging at an angle greater than a first angle and transmit light impinging at an angle that is less than a second angle. The separation between the first angle (722) and second angle (723) can be on the order of 20 degrees or more, but this angle can be reduced or eliminated when polarized light is used within the optical relay (500).

Claims

1. An optical relay for a head up display, the optical relay comprising:

a glare trap having angularly selectivity by being capable of reflecting light having an angle of incidence less than a first angle, and being capable of transmitting light having an angle of incidence greater than a second angle; and

a first optic arranged to receive light reflected off the glare trap at an angle of incidence less than the first angle, and to direct light through the glare trap at an angle of incidence greater than the second angle to exit the glare trap.

2. An optical relay as claimed in claim 1, further comprising:

a second optic arranged to receive the light reflected off the glare trap at an angle of incidence less than the first angle a first time, and to redirect light to the first optic that is reflected off the glare trap at an angle of incidence less than the first angle a second time.

3. An optical relay as claimed in claim 1, further comprising a lens disposed between a display and the glare trap to provide a relatively flat field or to position an eyebox, or combinations thereof.

4. An optical relay as claimed in claim 1, further comprising a wedge optic disposed between a display and the glare trap to adjust optical distortion in an image projected by the display.

5. An optical relay as claimed in claim 1, wherein light is incident upon the glare trap two or more times before passing through the glare trap.

6. An optical relay as claimed in claim 1, wherein the glare trap has an optical coating disposed on a surface thereof to provide an angular selectivity of the glare trap.

7. An optical relay as claimed in claim 1, wherein the first angle is separated from the second angle by about 20 degrees or more.

8. An optical relay as claimed in claim 1, wherein the light reflected off the glare trap at the angle of incidence less than the first angle comprises predominantly s-polarized light.

9. An optical relay as claimed in claim 8, further wherein the light directed through the glare trap at the angle of incidence greater than the second angle comprises one of predominantly p-polarized light or predominantly s-polarized light.

10. An optical relay as claimed in claim 8, wherein the first angle is separated from the second angle by about 10 degrees or more.

11. An optical relay as claimed in claim 1, wherein the glare trap comprises a pane of material that is at least partially transparent to light, further wherein the pane has an optical coating disposed on a surface thereof to provide an angular selectivity to the pane.

12. A head up display, comprising:

a housing;

a display module disposed in the housing; and

an optical relay disposed in the housing, the optical relay comprising;

a glare trap having angularly selectivity by being capable of reflecting light emitted from the display module having an angle of incidence less than a first angle, and being capable of transmitting light having an angle of incidence greater than a second angle; and

a first optic arranged to receive light reflected off the glare trap at an angle of incidence less than the first angle, and to direct light through the glare trap at an angle of incidence greater than the second angle to exit the housing through the glare trap.

13. A head up display as claimed in claim 12, wherein the glare trap has an optical coating disposed on a surface thereof to provide an angular selectivity of the glare trap.

14. A head up display as claimed in claim 12, wherein the first optic operates to provide an apparent magnified image disposed at a selected distance from a viewer.

15. A head up display as claimed in claim 12, wherein the light reflected off the glare trap at the angle of incidence less than the first angle comprises predominantly a s-polarized light, further wherein the light directed through the glare trap at the angle of incidence greater than the second angle comprises one of predominantly p-polarized light or predominantly s-polarized light.

16. An optical relay for a head up display, the optical relay comprising:

a glare trap having angular selectivity by being capable of reflecting light having an angle of incidence greater than a first angle, and by being capable of transmitting light having an angle of incidence less than a second angle; and

a first optic arranged to receive light reflected off the glare trap at an angle of incidence greater than the first angle, and to direct light through the glare trap at an angle of incidence less than the second angle to exit the glare trap;

wherein the light having the angle of incidence greater than the first angle comprises predominantly s-polarized light, wherein the light having the angle of incidence less than the second angle comprises one of predominantly p-polarized light or predominantly s-polarized light.

17. An optical relay as claimed in claim 16, wherein the glare trap comprises an optical coating disposed on a surface thereof to provide the angular selectivity between the first angle and the second angle, wherein the first angle is separated from the second angle by about 10 degrees or more.

18. An optical relay as claimed in claim 16, wherein the glare trap and the first optic comprises a singular piece of monolithic optical material, wherein the first optic comprises one or more surfaces of the singular piece of monolithic optical material.

19. An optical relay as claimed in claim 18, wherein at least one of the one or more surfaces comprises an optical coating disposed on a surface thereof to provide the angular selectivity to the glare trap.

20. An optical relay as claimed in claim 18, wherein at least one of the one or more surfaces comprises comprising an optical coating configured to provide greater reflectivity.

21. An optical relay for a head up display, the optical relay comprising:

a glare trap having transmission selectivity by being capable of reflecting light having a first polarization, and by being capable of transmitting light having a second polarization; and

a first optic arranged to receive light reflected off the glare trap at a first angle of incidence, and to direct light through the glare trap at a second angle of incidence to exit the glare trap;

wherein the light having the first angle of incidence comprises light substantially polarized in a first orientation, wherein the light having the second angle of incidence comprises light substantially polarized in a second orientation;

wherein the first orientation and the second orientation are substantially orthogonal.

22. The optical relay of claim 21, wherein the light polarized in the first orientation comprises predominantly s-polarized light, further wherein the light polarized in the second orientation comprises predominantly p-polarized light.

23. The optical relay of claim 22, wherein the first angle of incidence and the second angle of incidence are the same.

24. The optical relay of claim 22, wherein the first angle of incidence is less than the second angle of incidence.

25. The optical relay of claim 22, wherein the first angle of incidence is greater than the second angle of incidence.