Electric lamp and discharge devices: systems – Current and/or voltage regulation
Reexamination Certificate
1999-12-21
2001-06-12
Philogene, Haissa (Department: 2821)
Electric lamp and discharge devices: systems
Current and/or voltage regulation
C315S307000, C315S244000, C315SDIG007, C348S771000, C348S811000
Reexamination Certificate
active
06246185
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the field of high intensity arc discharge lamps, more particularly to power supplies for high frequency high intensity arc discharge lamps.
BACKGROUND OF THE INVENTION
Arc lamps have long been used to provide a high intensity beam of light for use in a projection display system. Many of the projection display systems in use today, whether a traditional theater movie projectors or a micromirror based conference room projector, use an arc lamp as a light source. Arc lamps provide a high intensity light beam with a color spectrum suitable for image projection in a relatively small package.
Some arc lamps use an alternating current supply to drive the lamp. Changes in the polarity of the drive current create fluctuations in the intensity of the light generated by the light source. These fluctuations are not a concern for most types of displays. The fluctuations, however, degrade the projected image when they occur only during a portion of an image created by binary pulse width modulation (PWM). In order to use an arc lamp, binary PWM display systems must be synchronized to the fluctuations. Synchronizing the display system to the arc lamp increases the cost of the system and often reduces the brightness of the display system.
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 a high frequency arc lamp power supply and display system using the high frequency arc lamp and supply. According to one embodiment of the disclosed invention, a display system is disclosed. The display system comprising: a light source, a modulator array, and a controller providing image data signals to the modulator array. The light source provides a periodically varying beam of light, wherein the period of the light source output is equal to or less than one tenth the LSB period of the display.
According to another embodiment of the invention, a power supply is disclosed. The power supply produces a high frequency signal to drive an arc lamp. Yet another embodiment of the disclosed invention provides a method of displaying an image. The method comprising: pulsing a light source to provide a periodic beam of light along a light path, and pulse width modulating said beam of light with a spatial light modulator. The period of the periodically varying beam of light is less than 0.1 times a least significant pulse width period so that several periods of fluctuations are integrated in each LSB period.
REFERENCES:
patent: 5192946 (1993-03-01), Thompson et al.
patent: 5504504 (1996-04-01), Markandey et al.
patent: 5510824 (1996-04-01), Nelson
patent: 5774196 (1998-06-01), Marshall
patent: 6072283 (2000-06-01), Hedrei et al.
Brady III Wade James
Brill Charles A.
Philogene Haissa
Telecky , Jr. Frederick J.
Texas Instruments Incorporated
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