Head up display (HUD) using a bent waveguide assembly

• US 9,507,150 B1
• Filed: 05/10/2013
• Issued: 11/29/2016
• Est. Priority Date: 09/30/2011
• 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: Stratton, Eric P., Buchholz, Christopher M., Keith, Christopher A., Brown, Robert D., Stanley, James H.
• Primary Examiner(s): Pham, Thomas K
• Assistant Examiner(s): Pichler, Marin
• Application Number:
  US13/892,026
• Time in Patent Office: 1,299 Days
• Field of Search: 359/566, 359/569, 359/572, 359/575, 359/576, 359/13, 359/630, 359/632, 359/633, 349 7- 9, 348/115
• US Class Current: 1/1
• CPC Class Codes: B64D 43/00 Arrangements or adaptations of instruments arrangements of cameras B64D47/08; aeronautical measuring instruments per se G01C
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/0145 creating an intermediate image
• CPC Class Codes: G02B 2027/0194 with combiner of laminated type, for optical or mechanical aspects
• 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 27/0149 characterised by mechanical features G02B27/0176 takes precedence
• CPC Class Codes: G02B 27/4205 having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
• CPC Class Codes: G02B 5/18 Diffraction gratings holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02F 1/163 Operation of electrochromic cells, e.g. electrodeposition cells; Circuit arrangements therefor

Abstract

The head up display provides light from an image source. The head up display includes a waveguide assembly comprising a first waveguide for disposition at an angle with respect to a top surface of a glare shield and a second waveguide disposed at an angle with respect to the first waveguide. The first waveguide has a first diffractive coupler at a first end and a second waveguide has a second diffractive coupler at a second end. The first waveguide is positioned as a combiner and allows viewing of an outside scene and information from the image source. At least part of the first waveguide is disposed beneath the top surface of a glare shield.

Claims

1. A head up display for providing light from an image source, the head up display for disposition in a vehicle having a glare shield disposed above vehicle instrumentation, the glare shield having a top surface, the head up display comprising:

a waveguide assembly comprising a first waveguide disposed at an angle with respect to the top surface of the glare shield and a second waveguide disposed at an angle with respect to the first waveguide, the first waveguide having a first diffractive coupler at a first end of the first waveguide and the second waveguide having a second diffractive coupler at a second end of the second waveguide, and the first waveguide being positioned as a combiner and allowing viewing of an outside scene and information from the image source, wherein at least part of the first waveguide is configured to be disposed beneath the top surface of the glare shield, wherein the second waveguide is disposed entirely below the top surface and a first end of the second waveguide provides light to a second end of the first waveguide beneath the top surface of the glare shield, wherein the second waveguide is configured so that the light travels from the second end of the first waveguide to the first end of the second waveguide by total internal reflection, wherein the first waveguide and the second waveguide are not a single waveguide and the first waveguide is tilted with respect to the second waveguide, wherein the second diffractive coupler is provided at a planar main surface of the second waveguide, the planar main surface being approximately parallel to the glare shield.

2. The head up display of claim 1, wherein the first and second diffractive couplers are diffraction gratings.

3. The head up display of claim 2, wherein the first and second diffractive couplers are surface relief gratings.

4. The head up display of claim 3, wherein the first and second diffractive couplers are holographic diffractive elements and the vehicle is an aircraft.

5. The head up display of claim 1, wherein the image source is part of a projector disposed entirely below the top surface of the glare shield, wherein the projector is disposed below the second waveguide at the second end of the second waveguide, wherein the second waveguide is disposed substantially parallel to the top surface of the glare shield.

6. The head up display of claim 1, wherein the first waveguide is disposed at an obtuse degree angle with respect to the second waveguide.

7. The head up display of claim 5, wherein light from the image source enters the second waveguide via the second diffractive coupler at the second end vertically with respect to gravity at the planar main surface, the planar main surface being a bottom surface and the bottom surface is horizontal with respect to gravity.

8. The head up display of claim 7, wherein second waveguide is at an obtuse angle with respect to the first waveguide.

9. The head up display of claim 1, wherein the light from a primary ray enters the first waveguide at a 90°

angle from a surface of the first waveguide and leaves the second waveguide at a 90°

angle from a surface of the second waveguide.

10. The head up display of claim 1, wherein the second diffractive coupler has a greater efficiency than the first diffractive coupler.

11. A cockpit comprising:

a glare shield for shielding aircraft instrumentation having a top surface; and

a head up display comprising;

a collimator; and

a combiner assembly, wherein the combiner assembly includes a first waveguide positioned to receive light from the collimator, wherein the combiner assembly includes a second waveguide disposed as a combiner, the second waveguide being disposed at an angle with respect to the first waveguide, the second waveguide being disposed at least partially above a top surface of the glare shield, the first waveguide having a first waveguide end disposed next to a second waveguide end of the second waveguide beneath the top surface of the glare shield, the first waveguide and the collimator being entirely disposed beneath the top surface of the glare shield, wherein the collimator is entirely disposed beneath a main planar surface of the first waveguide, wherein the main planar surface includes an input coupler configured to receive light from the collimator and the main planar surface is disposed approximately parallel to the top surface of the glare shield.

12. The cockpit of claim 11, wherein image source includes a laser or LED illuminator providing light through a beam splitter.

13. The cockpit of claim 11, wherein an output diffraction grating for the combiner is disposed above the glare shield and the second waveguide is not parallel to a top surface of the glare shield.

14. The cockpit of claim 11, wherein the first waveguide includes a diffraction grating.