Auto focus system for a SLM based image display system
First Claim
1. An image display system, comprising:
- a light source generating light;
a spatial light modulator modulating said light to form an image comprised of pixels;
a display image plane;
an optical system focusing said image on said image plane;
a sensor sensing a focus of at least one said pixel projected on said image plane and providing a sensor output indicative thereof, said sensor output being a function of sensed sharpness of multiple said pixels projected on said image plane, and said sensed pixels have a high contrast in intensity from an “
on”
pixel to an “
off”
pixel; and
adjustment means for altering a parameter of said optical system a function of said sensor output.
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Accused Products
Abstract
An image display system (10) having an auto-focus system (24). An image sensor (20) such as a CCD camera, senses the sharpness of pixels (26) comprising a portion of the image at a screen (16), preferably a magnified portion of the image. A sensor data processor (22) processes the pixel data from the sensor (20), and instructs the auto focus system (24) to adjust an optical parameter such as the focal length of a projector lens (14) as a function of the sensor (20) output. A DMD-type SLM is preferably utilized due to the uniform geometric features of the pixel mirrors, but other SLM'"'"'s can be used. The sharpness or contrast between an “on” and an “off” pixel is sensed, and preferably a 10×10 array of pixels arranged in a checker board pattern is sensed.
92 Citations
36 Claims
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1. An image display system, comprising:
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a light source generating light;
a spatial light modulator modulating said light to form an image comprised of pixels;
a display image plane;
an optical system focusing said image on said image plane;
a sensor sensing a focus of at least one said pixel projected on said image plane and providing a sensor output indicative thereof, said sensor output being a function of sensed sharpness of multiple said pixels projected on said image plane, and said sensed pixels have a high contrast in intensity from an “
on”
pixel to an “
off”
pixel; and
adjustment means for altering a parameter of said optical system a function of said sensor output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of focusing a display system including a light source generating light, a spatial light modulator (SLM) modulating the light, and an optical system comprising a projection lens focusing the modulated light on a display image plane, comprising the steps of;
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a) illuminating the SLM with the light to define an image comprised of pixels at the display image plane;
b) sensing a sharpness of at least one pixel of the image at the display image plane, said sensing is performed from adjacent the projection lens, said sensing performed by sensing a transition between an “
on”
pixel and an “
off”
pixel; and
c) adjusting an optical parameter of the optical system as a function of the sensed pixel sharpness. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A method of focusing a display system including a light source generating light, a spatial light modulator (SLM) modulating the light, and an optical system focusing the modulated light on a display image plane, comprising the steps of;
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a) illuminating the SLM with the light to define an image comprised of pixels at the display image plane;
b) sensing a sharpness of at least one pixel of the image at the display image plane, by sensing a transition between an “
on”
pixel and an “
off”
pixel; and
c) adjusting an optical parameter of the optical system as a function of the sensed pixel sharpness. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A method of focusing a display system including a light source generating light, a spatial light modulator (SLM) modulating the light, and an optical system focusing the modulated light on a display image plane, comprising the steps of;
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a) illuminating the SLM with the light to define an image comprised of pixels at the display image plane, wherein said SLM is a micromechanical device having deflectable pixel-members with gaps defined therebetween;
b) sensing the sharpness of a portion of the image corresponding to the gaps between the pixel-members; and
c) adjusting an optical parameter of the optical system as a function of the sensed pixel sharpness. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
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31. A method of focusing a display system including a light source generating light, a micromechanical spatial light modulator (SLM) modulating the light, and an optical system comprising a projection lens focusing the modulated light on a display image plane, comprising the steps of;
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a) illuminating the SLM with the light to define an image comprised of pixels at the display image plane;
b) sensing, from adjacent the projection lens, a sharpness of at least one pixel of the image at the display image plane by sensing a portion of the image corresponding to gaps between deflectable pixel members; and
c) adjusting an optical parameter of the optical system as a function of the sensed pixel sharpness. - View Dependent Claims (32, 33, 34, 35, 36)
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Specification