Micro collimator system and method for a head up display (HUD)

• US 10,746,989 B2
• Filed: 09/10/2018
• Issued: 08/18/2020
• Est. Priority Date: 05/18/2015
• Status: Active Grant

• Current Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Brown, Robert D., Stratton, Eric P.
• Primary Examiner(s): Choi, William
• Application Number:
  US16/126,618
• Publication Number:
  US 20200026072A1
• Time in Patent Office: 708 Days
• Field of Search: 359630, 359631, 345 7- 9
• CPC Class Codes: G02B 17/0852 having a field corrector only
• CPC Class Codes: G02B 2027/0116 comprising devices for correcting chromatic aberration
• CPC Class Codes: G02B 2027/0127 comprising devices increasing the depth of field
• CPC Class Codes: G02B 2027/0141 characterised by the informative content of the display
• CPC Class Codes: G02B 2027/015 involving arrangement aiming to get less bulky devices
• CPC Class Codes: G02B 27/0056 by using a diffractive optical element
• 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 27/0103 comprising holographic elements
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 27/30 Collimators
• CPC Class Codes: G02B 27/4211 correcting chromatic aberrations G02B27/0056, G02B27/4222, G02B27/4227 take precedence
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G02B 6/0096 the lights guides being of the hollow type

Abstract

A head up display can use a catadioptric collimating system. The head up display includes an image source. The head up display also includes a collimating mirror, and a polarizing beam splitter. The light from the image source enters the beam splitter and is reflected toward the collimating mirror. The light striking the collimating mirror is reflected through the beam splitter toward a combiner. A field lens can include a diffractive surface. A corrector lens can be disposed after the beam splitter.

Claims

1. A head up display, comprising:

a projector comprising a polarizing beam splitter and a curved reflector, wherein the polarizing beam splitter is configured to provide light from an image source to the curved reflector so that the projector provides collimated light;

a light pipe configured to convey the collimated light from an input to an output, wherein the light pipe is configured to expand a pupil associated with the collimated light in a first dimension as the collimated light travels through the light pipe by striking four elongated sides of the light pipe; and

a combiner configured to receive the collimated light from the light pipe and expand the pupil in a second direction.

2. The head up display of claim 1, wherein the projector further comprises:

a corrector lens and a field lens with a diffractive surface for providing color correction and having a higher order of aberration control.

3. The head up display of claim 2, wherein the combiner is a waveguide having a top planar surface matching a bottom elongated side of the light pipe.

4. The head up display of claim 1, wherein the projector comprises a corrector lens, a field lens, the curved reflector, and the polarizing beam splitter provided in a package with a volume of less than 1 cubic centimeter.

5. The head up display of claim 1, wherein the light pipe comprises a diffraction grating at the input.

6. The head up display of claim 1, wherein the light pipe comprises two diffraction gratings.

7. The head up display of claim 1 further comprising:

a second light pipe disposed between the light pipe and the combiner; and

a gradient reflective coating between the light pipe and the second light pipe.

8. The head up display of claim 1, further comprising:

an input component between the projector and the light pipe.

9. The head up display of claim 8, wherein the input component comprises two diffraction gratings.

10. A method of providing information to a pilot, the method comprising:

providing light from a light source through a fold element to an image source and folding light from the image source using the fold element;

reflecting the light from the image source within a polarizing beam splitter to a curved reflective surface;

providing light from the curved reflective surface through the polarizing beam splitter to a corrector lens; and

providing light from the corrector lens as collimated light to a light pipe.

11. The method of claim 10, further comprising providing the light from the corrector lens through a field lens comprising a diffractive surface.

12. The method of claim 11, wherein the fold element is a polarizing beam splitting component.

13. The method of claim 10, further comprising:

diffracting light out of a waveguide to the pilot.

14. The method of claim 13, further comprising:

diffracting light into the waveguide from the light pipe.

15. A head up display system, comprising:

a collimator;

at least one light pipe;

a waveguide comprising an output diffraction grating associated with a first main planar surface, wherein the light pipe is configured so light travels through the light pipe in a corkscrew fashion and is injected into the waveguide.

16. The head up display system of claim 15, wherein the light pipe has an elongated side matching a top planar side of the waveguide, the top planar side being disposed perpendicular to the first main planar surface.

17. The head up display system of claim 16, wherein the light pipe comprises a gradient diffraction grating for injecting the light into the top planar side of the waveguide.

18. The head up display system of claim 16, wherein the collimator comprises on axis arrangement.

19. The head up display system of claim 16, wherein an exit pupil for the collimator is at least three inches wide.

20. The head up display system of claim 15, wherein the light pipe comprises an input grating.