Vehicle head-up display (HUD)

Patent metadata

Field	Value
Publication number	US-12344093-B2
Application number	US-202118012948-A
Country	US
Kind code	B2
Filing date	Jun 27, 2021
Priority date	Jun 27, 2020
Publication date	Jul 1, 2025
Grant date	Jul 1, 2025

Abstract

A vehicular head-up display (HUD) for displaying an image to a user of a vehicle having a windshield ( 15 ) includes an image projector ( 14 ) outputting a collimated image and an optical aperture expander. The optical aperture expander includes a light-guide optical element (LOE) ( 10 ) having two major external surfaces ( 30 a, 30 b ). The image projector ( 14 ) injects the collimated image so as to propagate within the LOE by internal reflection at the major external surfaces. The LOE also has a set of parallel partially-reflecting internal surfaces ( 12 ) which progressively couple out the image illumination from the LOE. The optical aperture expander is deployed such that the image illumination coupled-out of the LOE ( 12 ) follows a light path including a reflection from a surface associated with the windshield ( 15 ) of the vehicle so as to be visible to the user while the user looks at a scene beyond the windshield.

First claim

What is claimed is:

1. A vehicular head-up display (HUD) for displaying an image to a user of a vehicle having a windshield, the HUD comprising:
(a) an image projector comprising an image generator and collimating optics, the image projector outputting image illumination corresponding to a collimated image; and
(b) an optical aperture expander comprising at least a first light-guide optical element (LOE), the LOE having a pair of mutually-parallel major external surfaces, the image projector being optically coupled to the optical aperture expander such that the image illumination propagates within the LOE by internal reflection at the major external surfaces, the LOE further comprising at least one set of mutually-parallel partially-reflecting surfaces internal to the LOE and oblique to the major external surfaces, the set of partially-reflecting surfaces progressively coupling out the image illumination from the LOE,
wherein the optical aperture expander is deployed such that the image illumination coupled-out of the LOE follows a light path including exiting the LOE from one of the pair of major external surfaces facing away from the windshield, being reflected from a reflective element having optical power, passing back through the LOE and being reflected from a surface associated with the windshield of the vehicle so as to be visible to the user while the user looks at a scene beyond the windshield,
wherein the surface associated with the windshield is non-planar, and wherein the optical power of the reflective element is configured to at least partially compensate for an optical aberration introduced to the image by reflection from the surface associated with the windshield.

2. The HUD of claim 1 , wherein the optical aperture expander further comprises a second set of mutually-parallel partially-reflecting surfaces deployed non-parallel to the first set of partially-reflecting surfaces, the second set of partially-reflecting surfaces being deployed to progressively redirect image illumination from the image projector towards the first set of partially-reflecting surfaces.

3. The HUD of claim 2 , wherein the second set of partially-reflecting surfaces are located within the LOE between the pair of major external surfaces.

4. The HUD of claim 2 , wherein the second set of partially-reflecting surfaces are located within a second LOE bounded by a second pair of major external surfaces.

5. The HUD of claim 4 , wherein the second LOE is deployed adjacent to one of the major external surfaces of the first LOE that is further from the windshield of the vehicle.

6. The HUD of claim 1 , wherein the reflective optical element is further configured to define an apparent distance of the image as viewed by the user after reflection from the surface associated with the windshield.

7. The HUD of claim 1 , wherein the light path includes a first reflection from the surface associated with the windshield of the vehicle at a high angle of incidence, an intermediate reflection from an additional reflective surface, and a second reflection from the surface associated with the windshield, so as to be visible to the user while the user looks at a scene beyond the windshield.

8. The HUD of claim 7 , wherein the surface associated with the windshield is an angularly-selective reflector configured to have a first reflectivity for light incident normal to the surface and a second reflectivity, less than the first reflectivity, for light at an angle of incidence greater than 45 degrees.

9. The HUD of claim 7 , wherein the additional reflective surface is a polarized beam splitter, and wherein a quarter-wave plate is interposed in the light path between the surface associated with the windshield and the additional reflective surface.

10. The HUD of claim 9 , wherein the surface associated with the windshield and the quarter-wave plate are both integrated into the windshield.

11. The HUD of claim 10 , further comprising a second quarter-wave plate integrated with the windshield and located on the far side of the surface from the user.

12. The HUD of claim 9 , wherein the polarized beam splitter is shaped to provide optical power to at least partially compensate for an optical aberration introduced to the image by reflection from the surface associated with the windshield.

13. A system comprising a first HUD and a second HUD, each of the first and second HUDs being implemented according to claim 1 , wherein each of the first and second HUDs provides a different region of a field of view visible to the user and/or renders the field of view visible from different regions of an eye-motion box.

14. The system of claim 13 , wherein the first and second HUDs are deployed in side-by-side relation.

15. The system of claim 13 , wherein the first and second HUDs are deployed in at least partially overlapping relation.

Assignees

• Lumus Ltd

Inventors

• Ronen Eitan
• Grobman Ari
• Gelberg Jonathan
• Frommer Aviv
• Glikman Eli

Classifications

• B60K35/22

  Display screens · CPC title

• B60K37/00

  Dashboards (as road-vehicle superstructure sub-units B62D25/14) · CPC title

• B60K35/60

  Instruments characterised by their location or relative disposition in or on vehicles (arrangements of lighting devices on dashboards B60Q3/10) · CPC title

• B60K2360/336

  Light guides · CPC title

• B60K2360/334

  Projection means · CPC title