Head-up display

• US 20060007055A1
• Filed: 06/28/2004
• Published: 01/12/2006
• Est. Priority Date: 06/28/2004
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Haim, Elias S., Larson, Brent D., Dubin, Matthew B.
• Granted Patent: US 7,482,996 B2
• Time in Patent Office: Days
• US Class Current: 345/8
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00

Abstract

Methods and apparatus are provided for a combined image on a head-up display. A data image display provides a first part of a combined image. An optical input provides a second part of the combined image, e.g., the background scene. A combiner superimposes the first and second parts to provide the combined image to the viewer. The data image display preferentially delivers s-polarized light to the combiner, which has a selective reflectance region for preferentially reflecting s-polarized light in a wavelength region of interest. In a preferred embodiment, the data image display comprises a backlight, a liquid crystal layer and two polarizers oriented so that the data images directed toward the combiner are s-polarized with respect to the selective reflectance region. A polarization rotation element may also be used in the data image display to facilitate s-polarization orientation.

Claims

1. A head-up display combining at least first and second images so as to be simultaneously visible to a viewer looking at the head-up display, comprising:

a data display source configured to supply the first image;

an optical input configured to supply the second image; and

a combiner coupled to the data display source and the optical input, the combiner configured to reflect the first image toward the viewer and transmit the second image toward the viewer, wherein the first image is substantially s-polarized with respect to the combiner.

2. The display of claim 1 wherein combiner comprises a surface layer for receiving and reflecting the first image and a supporting optically transparent body under the surface layer, wherein the surface layer and the body have different optical properties such that the surface layer preferentially reflects s-polarized light received from the data display toward the viewer.

3. The display of claim 2 wherein the substrate preferentially transmits p-polarized light.

4. The display of claim 1 wherein the data display comprises:

a backlight;

a rear polarizer coupled to the backlight;

a liquid crystal layer coupled to the rear polarizer; and

a front polarizer coupled to the liquid crystal layer.

5. The display of claim 4 further comprising a polarization-rotating element coupled to the front polarizer.

6. The display of claim 5 wherein the polarization-rotating element is optically after the front polarizer.

7. The display of claim 5 wherein the polarization-rotating element is optically before the front polarizer.

8. The display of claim 4 further comprising a polarization-rotating element coupled between the liquid crystal layer and the front polarizer.

9. The display of claim 4 wherein the liquid crystal layer comprises an in-plane nematic liquid crystal material.

10. The display of claim 4 wherein the liquid crystal layer comprises a twisted nematic liquid crystal material.

11. The display of claim 1 wherein the combiner is tilted at an angle so as to approach the Brewster Angle for transmitted p-polarized light from the data image source.

12. The display of claim 1 wherein the combiner is tilted at an angle so as to approach the Brewster Angle for light from the optical input for the second image.

13. The display of claim 1 wherein the data display source is substantially viewing angle symmetric for binocular vantage point pairs associated with the viewer.

14. The display of claim 1 wherein the first image has a direction of polarization and the data display source has a viewing angle symmetry axis that is perpendicular to the direction of polarization of the first image.

15. A head-up display comprising:

a source configured to emit first light containing a data image;

an optical input configured to emit second light derived from a forward scene; and

a combiner configured to having at least a first surface and superpose the first and second light to thereby provide a combined image,

wherein the first light is s-polarized with respect to the first surface of the combiner.

16. The display of claim 15 wherein the first surface of the combiner optically faces toward the source for providing the first light and toward a viewer of the combined image.

17. The display of claim 15 wherein the first surface comprises a layer that selectively reflects the s-polarized light.

18. The display of claim 17 wherein the source for providing the first light comprises:

a backlight;

a first polarizer coupled to and receiving light from the backlight;

a liquid crystal containing layer coupled to and receiving light from the first polarizer;

a second polarizer coupled to and receiving light from the liquid crystal containing layer.

19. The display of claim 18 further comprising a wavelength selective polarization-rotating element coupled to the second polarizer.

20. A head-up display for supplying a combined image to a viewer, comprising:

a data image display configured to supply a first part of the combined image;

an optical input configured to supply a second part of the combined image; and

a combiner configured to receive and combine the first and second parts to provide the combined image to the viewer,

wherein the combiner has thereon a selective reflectance region that preferentially reflects s-polarized light of the first part in a wavelength region of interest, and

wherein the data image display comprises a backlight, an LC layer and two or more polarizers oriented so that data images in the first part directed toward the combiner are s-polarized with respect to the selective reflectance region of the combiner.

21. The head-up display of claim 20 further comprising a polarization rotation element coupled to the data image display.

22. The head-up display of claim 20 wherein the selective reflectance region preferentially transmits p-polarized light incident thereon.

23. The head-up display of claim 20 wherein the data image display is substantially viewing angle symmetric for binocular vantage point pairs associated with the viewer.

24. The head-up display of claim 20 wherein the data image display has a viewing angle symmetry axis that is perpendicular to the s-polarized light of the first part.