High-dimming-ratio avionics display

Abstract

Disclosed are dual-light-source, high dimming-ratio avionics displays with digital light processing projector technology for rendering a visual display from generated light. The dual light sources are directed towards a beam splitter adapted to pass a substantial portion of the light from the first light source and to reflect a minority portion of the light from the second light source. An image is rendered at a substantially transparent, selectively reflective substrate adapted to reflect light of a range of visible wavelengths toward a viewer of the displays.

What is claimed is: 
     
         1 . A projector for rendering a visual display toward a user at one of a plurality of dimming levels comprising:
 a beam splitter having a first surface adapted to pass light received from a first light emitting diode out of the projector and a second surface adapted to pass light received from a second light emitting diode out of the projector;   a first light source comprising the first light emitting diode;   a second light source comprising the second light emitting diode;   a processing element coupled with the first light source and the second light source, the processing element configured to:
 determine a first light source intensity and a second light source intensity, 
 control the first light source to output light toward the beam splitter at the determined first light source intensity during high ambient light conditions, and 
 control the second light source to output light toward the beam splitter at the determined second light source intensity during ambient light conditions associated with low ambient light conditions; 
   wherein the second light source outputting light from the second light emitting diode toward the beam splitter is angularly disposed to light output by the first light source from the first light emitting diode.   
     
     
         2 . The projector of  claim 1 , wherein the determined second light source intensity is less than the determined first light source intensity. 
     
     
         3 . The projector of  claim 1 , wherein the high ambient light conditions are associated with direct sunlight, and wherein the low ambient light conditions are associated with darkness. 
     
     
         4 . The projector of  claim 1 , wherein the beam splitter is orientated at a  45 -degree angle to the first light emitting diode. 
     
     
         5 . The projector of  claim 1 , wherein the beam splitter is orientated at a  45 -degree angle to the second light emitting diode. 
     
     
         6 . The projector of  claim 1 , wherein the first light source further comprises a first light emitting diode drive circuit, and wherein the second light source further comprises a second light emitting diode drive circuit. 
     
     
         7 . The projector of  claim 6 , wherein the processing element is further configured to:
 control the brightness of the first light source by controlling the first light emitting diode drive circuit to select a current level for the first light emitting diode, and   control the brightness of the second light source by controlling the second light emitting diode drive circuit to select a current level for the second light emitting diode.   
     
     
         8 . The projector of  claim 7 , wherein the first light emitting diode drive circuit and the second light emitting diode drive circuit select the brightness of the first light emitting diode and the second light emitting diode, respectively, by means of pulse width modulation. 
     
     
         9 . The projector of  claim 8 , wherein the processing element is able to control the first light emitting diode drive circuit and the second light emitting diode drive circuit to provide a dimming ratio of at least 200,000-to-1. 
     
     
         10 . The projector of  claim 1 , wherein the beam splitter passes light received from the first light emitting diode and the second light emitting diode having a plurality of wavelengths, the plurality of wavelengths including wavelengths associated with green light. 
     
     
         11 . The projector of  claim 1 , wherein the visual display is projected forward at eye-level of a pilot of an aircraft on a head-up display. 
     
     
         12 . The projector of  claim 11 , wherein the light output by the projector from the first light source at the determined first light source intensity is visible to the pilot in ambient light conditions associated with direct sunlight. 
     
     
         13 . The projector of  claim 11 , wherein the light output by the projector from the second light source at the determined second light source intensity is visible to the pilot in ambient light conditions associated with darkness. 
     
     
         14 . A projector for rendering a visual display toward a user at one of a plurality of dimming levels comprising:
 a beam splitter having a first surface adapted to pass light received from a first light emitting diode out of the projector and a second surface adapted to pass light received from a second light emitting diode out of the projector;   a first light source comprising the first light emitting diode;   a second light source comprising the second light emitting diode;   a processing element coupled with the first light source and the second light source, the processing element configured to:
 determine a first light source intensity and a second light source intensity, 
 control the first light source to output light toward the beam splitter at the determined first light source intensity during ambient light conditions associated with direct sunlight, and 
 control the second light source to output light toward the beam splitter at the determined second light source intensity during ambient light conditions associated with ambient light conditions associated with darkness, the determined second light source intensity being less than the determined first light source intensity; 
   wherein the second light source outputting light from the second light emitting diode toward the beam splitter is angularly disposed to light output by the first light source from the first light emitting diode.   
     
     
         15 . The projector of  claim 14 , wherein the beam splitter is orientated at a  45 -degree angle to the first light emitting diode, and wherein the beam splitter is orientated at a  45 -degree angle to the second light emitting diode. 
     
     
         16 . The projector of  claim 14 , wherein the first light source further comprises a first light emitting diode drive circuit and the second light source further comprises a second light emitting diode drive circuit, and wherein the processing element is further configured to:
 control the brightness of the first light source by controlling the first light emitting diode drive circuit to select a current level for the first light emitting diode, and   control the brightness of the second light source by controlling the second light emitting diode drive circuit to select a current level for the second light emitting diode.   
     
     
         17 . The projector of  claim 14 , wherein the visual display is projected forward at eye-level of a pilot of an aircraft on a head-up display, and wherein the light output by the projector from the second light source at the determined second light source intensity is visible to the pilot in ambient light conditions associated with darkness. 
     
     
         18 . A projector for rendering a visual display toward a user at one of a plurality of dimming levels comprising:
 a beam splitter having a first surface adapted to pass light received from a first light emitting diode out of the projector and a second surface adapted to pass light received from a second light emitting diode out of the projector;   a first light source comprising the first light emitting diode;   a second light source comprising the second light emitting diode;   a processing element coupled with the first light source and the second light source, the processing element configured to:
 determine a first light source intensity and a second light source intensity, 
 control the first light source to output light toward the beam splitter at the determined first light source intensity during ambient light conditions associated with direct sunlight, and 
 control the second light source to output light toward the beam splitter at the determined second light source intensity during ambient light conditions associated with ambient light conditions associated with darkness, the determined second light source intensity being less than the determined first light source intensity; 
   wherein the second light source outputting light from the second light emitting diode toward the beam splitter is angularly disposed to light output by the first light source from the first light emitting diode;   wherein the beam splitter is orientated at a 45-degree angle to each of the first light emitting diode and the second light emitting diode.   
     
     
         19 . The projector of  claim 18 , wherein the first light source further comprises a first light emitting diode drive circuit and the second light source further comprises a second light emitting diode drive circuit, and wherein the processing element is further configured to:
 control the brightness of the first light source by controlling the first light emitting diode drive circuit to select a current level for the first light emitting diode, and   
       control the brightness of the second light source by controlling the second light emitting diode drive circuit to select a current level for the second light emitting diode. 
     
     
         20 . The projector of  claim 19 , wherein the visual display is projected forward at eye-level of a pilot of an aircraft on a head-up display, and wherein the light output by the projector from the second light source at the determined second light source intensity is visible to the pilot in ambient light conditions associated with darkness.