Gray level control method and optical projection system
AssigneeDelta Electronics, Inc.
InventorYu-Chang Wang
Life of this patent
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Abstract
The invention provides a gray level control method for outputting a total gray level during a total period, including: dividing the total period into M unit periods; alternatively outputting a gray level “0” or a selected gray level during each unit period; and integrating the gray levels output during the M unit periods to obtain the total gray level, wherein during each of N successive unit periods of the M unit periods the selected gray level is a first gray level, and during each of the remaining (M−N) unit periods the selected gray level is lower than the first gray level.
Claims19
A gray level control method for outputting a total gray level during a total period consisting of M unit periods, comprising:
- controlling a light source to continuously emitting light at variable brightness levels during the total period;
- controlling a light modulator to be switched on to pass the light of the light source or be switched off to block the light source for each of the M unit periods;
- selectively outputting one of a gray level “0” by switching on the light modulator and a specified gray level by switching off the light modulator during each unit period;
- and
- integrating the gray levels output during the M unit periods to obtain the total gray level,
- wherein during each of N successive unit periods of the M unit periods the specified gray level is a first gray level, and during each of the remaining (M−N) unit periods the specified gray level is lower than the first gray level,
- wherein M is a constant value, and the specified gray level for each unit period cannot be changed, and
- wherein the first gray level corresponds to the maximum brightness level that can be emitted by the light source.
An optical projection system, comprising:
- a light source;
- a light source driver driving the light source to change the brightness of the light source;
- a light modulator selectively switching whether or not to output the light from the light source;
- and
- a controller controlling the light modulator and the light source driver,
- wherein the controller controls the light modulator to be switched on or off for each one of M unit periods, and controls the light source driver to drive the light source to continuously output light at variable brightness levels during the M unit periods,
- wherein during each of N successive unit periods of the M unit periods the brightness level of the light source is equal to a first brightness, and during each of the remaining (M−N) unit periods the brightness level of the light source is lower than the first brightness, and
- wherein the overall brightness output from the light modulator during the M unit periods corresponds to a total gray level,
- wherein M is a constant value, and the brightness level for each unit period cannot be changed, and
- wherein the first brightness corresponds to the maximum brightness level that can be emitted by the light source.
Dependencies are inferred from the claim text.