HEAD-UP DISPLAY WITH BRIGHTNESS CONTROL

• US 20090213037A1
• Filed: 02/19/2009
• Published: 08/27/2009
• Est. Priority Date: 02/19/2008
• Status: Active Grant

• Current Assignee: Saab AB
• Original Assignee: Saab AB
• Inventors: SCHON, Peter
• Granted Patent: US 9,069,163 B2
• Time in Patent Office: Days
• US Class Current: 345/7
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/014 comprising information/image processing systems
• CPC Class Codes: G02B 2027/0141 characterised by the informative content of the display
• CPC Class Codes: G02B 27/01 Head-up displays

Abstract

A head-up display system suitable for an aircraft. The head-up display including an image source arranged outside the desired field of view of an observer and where the intensity of symbols of the image source are modulated differ depending on their perceived position relative to the horizon line. A light source is arranged for providing light to an image source which is arranged to modulate the light of the light source thereby creating an image for the head up display. A brightness control unit have inputs for vehicle pitch- and roll angle, and a calculator configured to calculate, based on the pitch and roll angles, the current position in the image of a virtual horizon line, corresponding to the real horizon line as perceived by the observer, and for controlling the brightness of symbols above the virtual horizon line to be different from the brightness of symbols below the line.

Claims

1. A head-up display system for a vehicle, comprising:

a projector part positioned outside a field of view of an observer;

a partially reflecting combiner arranged in the field of view of the observer to provide for an image of the projector part to be combined with a view of outside terrain thereby providing the observer with a view of the outside terrain with symbols superimposed thereto;

a light source for providing light of the projector part;

an image generator display for modulating the light of the light source thereby creating an image to be combined with the view of the outside terrain; and

an image generator controller having a brightness control unit arranged to provide different brightness of different portions of the image;

wherein the brightness control unit comprises inputs for vehicle pitch angle and roll angle, and a calculator configured to calculate, based on said pitch and roll angles, a position in the image of a virtual horizon line, corresponding to a real horizon line as perceived by the observer, and to calculate which portions of the image that are above said virtual horizon line, and which portions that are below the virtual horizon line, and wherein the brightness control unit can control the brightness of symbols above said virtual horizon line to be different from the brightness of symbols below the virtual horizon line.

2. The head up display system according to claim 1, wherein said image generator display comprises a Digital Micro-mirror Device.

3. The head up display system according to claim 2, wherein said brightness control unit is arranged to control pulse modulation of the Digital Micro-mirror Device.

4. The head up display system according to claim 1, wherein said image generator display comprises a Liquid Crystal Display.

5. The head up display system according to claim 4, wherein said brightness control unit is arranged to control a transmittance for each pixel of the Liquid Crystal Display.

6. A head-up display-symbol intensity control method for providing symbol intensity adjustment for symbols of a head up display, the method comprising:

calculating a position of a virtual horizon line on a head up display;

translating the position of virtual horizon line on the head up display to a corresponding position on an image source display;

determining which area of the image source display that corresponds to an area above the virtual horizon line, and which area that corresponds to an area below the virtual horizon line; and

modulating the image source to display symbols in the area above virtual horizon line with a different intensity than the image source is modulated to display symbols in the area below the horizon line.

7. The method according to claim 6, wherein the difference in intensity is generated as a function being dependent on ambient light conditions.