Projection display system including a high fill ratio silicon spatial light modulator

Abstract

A display system includes a light source and a first optical system coupled to the light source and adapted to provide an illumination beam along an illumination path. The display system also includes a spatial light modulator positioned in the illumination path. The spatial light modulator includes a semiconductor substrate including a plurality of electrode devices and a hinge structure coupled to the semiconductor substrate. The hinge structure includes silicon material. The spatial light modulator also includes a mirror post coupled to the hinge structure and extending to a predetermined distance from the semiconductor substrate and a mirror plate coupled to the mirror post and overlying the plurality of electrode devices. The display system further includes a second optical system coupled to the spatial light modulator and adapted to project an image onto a projection surface.

1 . A display system comprising:
 a light source;   a first optical system optically coupled to the light source and adapted to provide an illumination beam along an illumination path;   a spatial light modulator positioned in the illumination path, the spatial light modulator comprising:
 a CMOS substrate including a plurality of multi-level electrode devices; 
 a hinge structure coupled to the CMOS substrate, wherein the hinge structure comprises silicon material; 
 a mirror post coupled to the hinge structure and extending to a predetermined distance from the CMOS substrate; and 
 a mirror plate coupled to the mirror post and overlying the plurality of multi-level electrode devices; and 
   a second optical system optically coupled to the spatial light modulator and adapted to project an image onto a projection surface.   
   
   
       2 . The display system of  claim 1  wherein the plurality of multi-level electrode devices comprise a first layer coupled to the CMOS substrate and a second layer coupled to the first layer and extending to a predetermined height from the CMOS substrate. 
   
   
       3 . The display system of  claim 1  wherein the mirror plate is rotated about the hinge structure to one or more deflection positions in response to electrical signals provided by the plurality of multi-level electrode devices. 
   
   
       4 . The display system of  claim 3  further comprising a color wheel positioned between the light source and the spatial light modulator, wherein the color wheel is operative to provide a sequential train of optical pulses, each optical pulse characterized by a different wavelength and wherein the one or more deflection positions produced in response to electrical signals in synchronous correspondence with a predetermined optical pulse. 
   
   
       5 . The display system of  claim 1  wherein the spatial light modulator further comprises a mirror stop comprising a first landing structure operative to terminate deflection of the mirror plate at a first deflection angle and a second landing structure operative to terminate deflection of the mirror plate at a second deflection angle. 
   
   
       6 . The display system of  claim 5  wherein an upper portion of the first landing structure and the second landing structure comprise a layer coplanar with the hinge structure. 
   
   
       7 . The display system of  claim 1  wherein the mirror plate further comprises a reflective surface applied on an uppermost surface of the mirror plate, the reflective surface comprising one of silicon/metal alloy, silicon/aluminum alloy, or Ti/Al and wherein the mirror plate comprises one of single crystal silicon, polysilicon, or amorphous silicon. 
   
   
       8 . A projection display system comprising:
 a spatial light modulator including a plurality of micro-mirrors controllably deflectable between a first deflection angle and a second deflection angle, wherein each micro-mirror of the plurality of micro-mirror is associated with a pixel of an image and wherein each micro-mirror comprises:
 one or more multi-level electrodes provided on a support substrate; 
 a hinge device coupled to the support substrate, wherein the hinge device comprises silicon material; 
 a mirror post coupled to the hinge device and extending away from the support substrate; and 
 a mirror plate coupled to the mirror post and overlying the one or more multi-level electrodes; 
   projection optics provided in a projection path lying along the first deflection angle and adapted to project the image on a projection surface;   optics provided in a light dump path lying along the second deflection angle and adapted to reduce an intensity of light propagating along the light dump path;   a plurality of light emitting diodes configured to produce a sequential train of optical pulses in an illumination beam, each one of the plurality of light emitting diodes producing an optical pulse of a different wavelength; and   illumination optics optically coupled to the plurality of light emitting diodes and adapted to direct the illumination beam to the spatial light modulator.   
   
   
       9 . The projection display system of  claim 8  further comprising a video display controller coupled to an input port and the one or more multi-level electrodes, the video display controller in electrical communication with the plurality of light emitting diodes and configured to receive input video signals and correspondingly produce electrical signals according to a pulse width modulation scheme. 
   
   
       10 . The projection display system of  claim 9  wherein at least a portion of the plurality of light emitting diodes is activated by the electrical signals and the mirror plate is angularly rotated on the hinge device between the first deflection angle and the second deflection angle in response to the electrical signals being provided by the plurality of multi-level electrode devices. 
   
   
       11 . The projection display system of  claim 9  wherein the electrical signals are configured by the video display controller to produce the first deflection angle during a first time period having a predetermined temporal characteristic and the second deflection angle during a second time period with a temporal characteristic being substantially the complement of the first time period. 
   
   
       12 . The projection display system of  claim 11  wherein the first time period is configured to produce a reflection of at least a portion of a predetermine optical pulse within the sequential train to the projection optics by the mirror plate being maintained at the first deflection angle. 
   
   
       13 . The projection display system of  claim 11  wherein the second time period is configured to produce a reflection of at least a portion of the sequential train to the optics in the light dump path by the mirror plate being maintained at the second deflection angle. 
   
   
       14 . The projection display system of  claim 8  wherein the first deflection angle and the second deflection angle are about 15° from a non-deflected position. 
   
   
       15 . A projection display system comprising:
 a spatial light modulator including a plurality of micro-mirrors controllably deflectable between a first deflection angle and a second deflection angle, wherein each micro-mirror of the plurality of micro-mirror is associated with a pixel of an image and wherein each micro-mirror comprises:
 one or more electrodes provided on a CMOS substrate; 
 a hinge device coupled to the CMOS substrate, wherein the hinge device comprises silicon material; 
 a mirror post coupled to the hinge device and extending away from the CMOS substrate; and 
 a mirror plate coupled to the mirror post and overlying the one or more electrodes; 
   optics provided in a projection path lying along the first deflection angle and adapted to project the image on a projection surface;   optics provided in a light dump path lying along the second deflection angle and adapted to reduce an intensity of light propagating along the light dump path;   a video display controller coupled to an input port and operative to receive input video signals, the video display controller configured to produce electrical signals according to a pulse width modulation scheme and corresponding to the input video signals;   one or more lasers operative as a light source and configured to produce a sequential train of optical pulses in an illumination beam, the one or more lasers in electrical communication with the video display controller and configured to produce an optical pulse of a different wavelength according to the electrical signals; and   illumination optics optically coupled to the one or more lasers and adapted to direct the illumination beam to the spatial light modulator.   
   
   
       16 . The projection display system of  claim 15  wherein the video display controller is coupled to the one or more electrodes and the electrical signals are configured to produce a deflection of a corresponding mirror plate in the spatial light modulator. 
   
   
       17 . The projection display system of  claim 15  wherein the video display controller is coupled to the one or more electrodes and configured to produce the first deflection angle during a first time period and the second deflection angle during a second time period. 
   
   
       18 . The projection display system of  claim 15  wherein the one or more electrodes further comprise at least one multi-level electrode having at least a first level and a second level and wherein the spatial light modulator further comprises a plurality of vias configured to provide electrical coupling between the first level of the one or more electrodes, the second level of the one or more electrodes, and the mirror plate of each micro-mirror. 
   
   
       19 . The projection display system of  claim 18  wherein electrical signals produced by the video display controller are coupled to the one or more electrodes to produce deflection of the mirror plates of predetermined ones of the plurality of micro-mirrors. 
   
   
       20 . The projection display system of  claim 15  wherein the one or more electrodes further comprise multi-level electrodes having at least a first level and a second level and a first set of vias providing electrical coupling between the first level of the one or more multi-level electrode devices and the second level of the one or more multi-level electrode devices.