Method for increasing the resolution of a spatial light modulator
View Patent ↗In a method for increasing the native resolution of a spatial light modulator, the light-modulating elements of the spatial light modulator are illuminated with spots of light that are smaller in size than the light-modulating elements. The spots of light are moved to different positions with respect to the light-modulating elements as different data are displayed. The light-modulating elements thus do double-duty (or triple-duty, or quadruple-duty, or more) as the spots of light are moved to different positions.
1. A method for displaying a color component of an image described by video words of a frame, the video words having bits with different bit ranks, said method comprising the steps of:
(a) for a given one of the bit ranks, actuating light-modulating elements of a spatial light modulator in accordance with values of some of the video words for the given bit rank;
(b) exposing the spatial light modulator to a light pattern that produces spots of light that are smaller than the light-modulating elements;
(c) for the given bit rank, actuating the light-modulating elements of the spatial light modulator in accordance with values of others of the video words for the given bit rank; and
(d) exposing the spatial light modulator to the light pattern, shifted with respect to the exposure in step (b).
2. The method of claim 1 , wherein the spatial light modulator is a digital micromirror device and the light-modulating elements are micromirrors, and wherein steps (a) and (c) comprise turning the micromirrors on or off.
3. The method of claim 1 , wherein the spatial light modulator is a digital micromirror device having an array of micromirrors that are disposed in an image-forming area of the digital micromirror device, and wherein steps (b) and (d) comprise exposing the digital micromirror device to light impinging on the image-forming area from a direction approximately perpendicular to the image-forming area.
4. The method of claim 3 , wherein micromirrors that are on reflect light at an acute angle with respect to the image-forming area, and further comprising intercepting the light that is reflected at the acute angle with a reflector that re-directs the light.
5. The method of claim 3 , wherein step (b) comprises passing light through a light pattern device when the light pattern device is in a first position, and step (d) comprises passing light through the light pattern device when the light pattern device is in a second position.
6. The method of claim 1 , wherein steps (b) and (d) are conducted using light having a first intensity, and further comprising the steps of:
(e) for another one of the bit ranks, actuating the light-modulating elements of a spatial light modulator in accordance with values of some of the video words for the another one of the bit ranks;
(f) exposing the spatial light modulator to a light pattern that produces spots of light that are smaller than the light-modulating elements, using light having a second intensity;
(g) for the another one of the bit ranks, actuating the light-modulating elements of the spatial light modulator in accordance with values of others of the video words for the another one of the bit ranks; and
(h) exposing the spatial light modulator to the light pattern, shifted with respect to the exposure in step (f), using light having the second intensity.
7. A method for displaying a color component of an image described by video words of a frame, the video words having bits with different bit ranks, said method comprising the steps of:
(a) generating light having the color of the color component;
(b) conveying the light along an optical path to an image-forming area of a digital micromirror device, the light impinging on the image-forming area from a direction perpendicular to the image forming area.
8. The method of claim 7 , wherein the optical path passes through a spot-forming unit, and further comprising actuating the spot-forming unit to produce light spots at different regions of the micromirrors of the digital micromirror device.
9. The method of claim 8 , wherein the spot-forming device comprises a light pattern device having a pattern of apertures, and further comprising focusing the apertures on the image-forming area.
10. A method for displaying a color component of at least a portion of an image, said at least a portion of the image being described by a set of video words having bits with different bit ranks, said method comprising the steps of:
(a) for a given one of the bit ranks, actuating micromirrors of a digital micromirror device in accordance with values of some of the video words for the given bit rank;
(b) exposing the spatial light modulator to a light pattern that produces spots of light on the micromirrors, the spots of light being smaller than the micromirrors;
(c) for the given bit rank, actuating the micromirros of the digital micromirror device in accordance with values of others of the video words for the given bit rank; and
(d) exposing the digital micromirror device to the light pattern, shifted with respect to the exposure in step (b).
11. The method of claim 10 , wherein the micromirrors that are disposed in an image-forming area of the digital micromirror device, and wherein steps (b) and (d) comprise exposing the digital micromirror device to light impinging on the image-forming area from a direction approximately perpendicular to the image-forming area.
12. The method of claim 11 , wherein micromirrors that are on reflect light at an acute angle with respect to the image-forming area, and further comprising intercepting the light that is reflected at the acute angle with a reflector that re-directs the light.
13. The method of claim 10 , wherein step (b) comprises passing light through a light pattern device when the light pattern device is in a first position, and step (d) comprises passing light through the light pattern device when the light pattern device is in a second position.
14. The method of claim 10 , wherein steps (b) and (d) are conducted using light having a first intensity, and further comprising the steps of:
(e) for another one of the bit ranks, actuating the micromirrors of the digital micromirror device in accordance with values of some of the video words for the another one of the bit ranks;
(f) exposing the digital micromirror device to a light pattern that produces spots of light on the micromirrors that are smaller than the micromirrors, the light-modulating elements, using light having a second intensity;
(g) for the another one of the bit ranks, actuating the micromirrors of the digital micromirror device in accordance with values of others of the video words for the another one of the bit ranks; and
(h) exposing the digital micromirror device to the light pattern, shifted with respect to the exposure in step (f), using light having the second intensity.