Head-up display

• US 20070217018A1
• Filed: 12/15/2006
• Published: 09/20/2007
• Est. Priority Date: 12/15/2005
• Status: Active Grant

• Current Assignee: Saab AB
• Original Assignee: Saab AB
• Inventors: Fredriksson, Arnold
• Granted Patent: US 7,391,574 B2
• Time in Patent Office: Days
• US Class Current: 359/631
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/015 involving arrangement aiming to get less bulky devices
• CPC Class Codes: G02B 27/0103 comprising holographic elements
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements

Abstract

A head-up display system including an image source with a projection lens where the lens projects an intermediate image on a diffuser, forming an intermediate image on the diffuser matt surface. A first planar semi-transparent mirror is arranged to reflect the intermediate image towards a head-up semi-transparent collimating mirror. The collimating mirror also combines the image with the background.

Claims

1-14. -14. (canceled)

15. A head-up display system, comprising:

an image source;

a projection lens arranged to receive an image from the image source;

a diffuser comprising a matt surface, wherein said projection lens is arranged relative to the diffuser to project an intermediate image on the diffuser matt surface;

a planar semi-transparent mirror arranged to receive the intermediate image from the diffuser; and

a head-up collimating mirror arranged to receive said intermediate image from the planar semi-transparent mirror.

16. The head-up display system according to claim 15, further comprising:

a folding mirror arranged optically between the projection lens and the diffuser.

17. The head-up display system according to claim 15, wherein said image source is a transmitting image source.

18. The head-up display system according to claim 15, wherein said image source is a reflecting image source.

19. The head-up display system according to claim 15, wherein the head-up collimating mirror has a radius of curvature having a center of curvature in the vicinity of a midpoint between eyes of a pilot viewing the display.

20. The head-up display system according to claim 15, wherein the diffuser matt surface has a radius of curvature that is arranged to be approximately one-half of a radius of curvature of the collimating mirror.

21. The head-up display system according to claim 15, wherein the diffuser comprises a ground or sand blasted surface.

22. The head-up display system according to claim 15, wherein the diffuser matt surface comprises a surface with a diffraction pattern or a holographic layer.

23. The head-up display system according to claim 15, wherein the collimating mirror and the semi-transparent flat mirror are designed to reflect a main part of one or a few colors while transmitting a main part of all other colors, and wherein the image generator generates guidance symbols, aiming marks and/or a thermal image having said color(s).

24. The head-up display system according to claim 15, wherein said image source comprises an image generating display and a light source where the light source comprises one or more light emitting diodes.

25. The head-up display system according to claim 24, further comprising:

a luminance control unit for adjusting an average brightness of the light source relative to a background brightness, such that image symbols become clearly visible.

26. The head-up display system according to claim 15, further comprising:

an alignment device for aligning an image seen by a pilot with a fuselage of a aircraft.

27. The head-up display system of claim 26, further comprising:

a flat mirror;

a detector focusing lens; and

a detector,

wherein said alignment device comprises a second semi-transparent mirror being arranged parallel, or with a known angle relative to the first semi-transparent mirror, wherein said second semi-transparent mirror is arranged to reflect light corresponding to a small part of an image towards the flat mirror, letting reflected light pass through the second semi-transparent mirror towards the detector focusing lens that focus a small part of the image on the detector.

28. The head-up display system according to claim 27, wherein said alignment device comprises an encoding unit for encoding the position of each pixel, and wherein the detector comprises electronics comprising means for determining a position in a display image that corresponds to a direction for a normal to the reference mirror, the system further comprising:

control electronics configured to move or adjust the image seen by the pilot, such that the image seen by the pilot becomes precisely aligned to the fuselage of the aircraft.