Optical: systems and elements – Optical modulator – Light wave temporal modulation
Reexamination Certificate
1999-12-21
2001-09-04
Sugarman, Scott J. (Department: 2873)
Optical: systems and elements
Optical modulator
Light wave temporal modulation
Reexamination Certificate
active
06285491
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
The following patents and/or commonly assigned patent applications are hereby incorporated herein by reference:
Patent No.
Filing Date
Issue Date
Title
5,278,652
March 23, 1993
Jan. 11, 1994
DMD Architecture and
Timing for Use in a
Pulse-Width Modulated
Display System
5,583,688
Dec. 21, 1993
Dec. 10, 1996
Multi-Level Digital
Micromirror Device
FIELD OF THE INVENTION
This invention relates to the field of display systems, more particularly to pulse-width modulated display systems using periodically varying light sources.
BACKGROUND OF THE INVENTION
Digital display systems temporally modulate light to create images. A typical digital display system uses a digital micromirror device (DMD) to selectively reflect portions of an incident beam of light to an image plane. The DMD is an array of mirrors that are rotated in one of two directions about a torsion hinge. In the first position (on), light incident the mirror is reflected towards an image plane, typically by way of a projection lens. The light reaching the image plane forms a bright spot on the image plane representing a picture element, or pixel. When the mirror is rotated in the opposite direction to a second position (off), the light reflected by the mirror does not reach the image plane and the pixel corresponding to the mirror in the off position is dark.
Intermediate intensities are created by rapidly cycling the mirror on and off. The amount of light reflected to the image plane is a function of the duty cycle of the mirror. The human eye, or other integrator such as a photosensitive medium located at the image plane, integrates the amount of light reaching each pixel over a period of time and creates the impression of an intermediate pixel brightness. Color images are formed by superimposing three simultaneously or sequentially-generated single-color images.
Although the duty cycle of the mirror controls the time during which light is reflected to the image plane, other factors may upset the relationship between pixel intensity and duty cycle. What is needed is a more efficient method of controlling pixel intensity in pulse-width modulated display systems.
SUMMARY OF THE INVENTION
Objects and advantages will be obvious, and will in part appear hereinafter and will be accomplished by the present invention which provides a method and system for adaptive temporal modulation of a periodically varying light source. One embodiment of the claimed invention provides a method of temporally modulating a light beam. According to this embodiment, a light source is provided for sourcing a beam of light along a light path. A light modulator is provided on the light path. The light modulator comprises an array modulator elements, each modulator element operable to selectively relay light incident the modulator element to an image plane in response to an image signal. The quantity of light provided by the light source is detected and a signal representing the light output is generated. A controller receives image data words and controls the operation of the light modulator, the controller serially provides each bit of the image data words to the light modulator for a separate time period in a frame period. The quantity of light output during the time period for each bit represents the relative weight of the bit.
According to another embodiment of the disclosed invention, display system is provided. The display system comprises a light source, a modulator array, a means for detecting the amount of light from the light source, and a controller. The controller receives image data and controls the modulator array. The image data comprises multiple bits of image data for each element in the modulator array. The controller provides bits of image data to the modulator array elements such that the total quantity of light directed by each modulator element to an image plane is proportional to the weight of the image data bit.
REFERENCES:
patent: 5278652 (1994-01-01), Urbanus et al.
patent: 5583688 (1996-12-01), Hornbeck
patent: 5969710 (1999-10-01), Doherty et al.
patent: 5986721 (1999-11-01), Jones, Jr. et al.
patent: 6201521 (2001-03-01), Doherty
Doherty Donald B.
Marshall Stephen W.
Perry Roger P.
Brady III Wade James
Brill Charles A.
Magee John
Sugarman Scott J.
Telecky , Jr. Frederick J.
LandOfFree
Adaptive temporal modulation of periodically varying light... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Adaptive temporal modulation of periodically varying light..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Adaptive temporal modulation of periodically varying light... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2485077