Seiko Epson Corporation

Infocus Corporation

Infocus Systems, Inc.

Steven E Stark

Henry Frazier Pruett

Edmund D Passon

A frame sequential color display projection system () of this invention includes an arc lamp () having a predetermined power rating for providing a source of polychromatic light that propagates through a color wheel () that sequentially provides R, G, B, and optionally, W light colors during respective sequential time periods. A display controller () is synchronized with the color wheel to generate color image data during the respective time periods. A light valve, such as a DMD (), receives the color image data for generating the frame sequential color display. A lamp ballast () is also synchronized with the color wheel to provide nominal and boosted power levels () to the arc lamp during selected ones of the time periods such that the projector provides a brighter, color-adjusted display without requiring the arc lamp to operate at an average power level exceeding its predetermined power rating.

Lamp power pulse modulation in color sequential projection displays

A frame sequential color display projection system ( ) of this invention includes an arc lamp ( ) having a predetermined power rating for providing a source of polychromatic light that propagates through a color wheel ( ) that sequentially provides R, G, B, and optionally, W light colors during respective sequential time periods. A display controller ( ) is synchronized with the color wheel to generate color image data during the respective time periods. A light valve, such as a DMD ( ), receives the color image data for generating the frame sequential color display. A lamp ballast ( ) is also synchronized with the color wheel to provide nominal and boosted power levels ( ) to the arc lamp during selected ones of the time periods such that the projector provides a brighter, color-adjusted display without requiring the arc lamp to operate at an average power level exceeding its predetermined power rating.

A multimedia projector (30) employing a color wheel (42) in a frame sequential color display system includes a light sensor (68) positioned to receive light scattered from a point in an optical path (34) after the color wheel. The light sensor detects particular colors of light propagating through red, green, and blue filter segments (R, G, and B) on the color wheel and toward a display device (50). The light sensor provides, without any adjustments, an inherently accurate timing mark signal (78) to a display controller (56) to ensure that red, green, and blue image data are properly synchronized with the respective filter segments R, G, and B. In particular, the light sensor receives polychromatic light through a yellow optical filter (74) to illuminate an optoelectric detector (70) that is responsive to visible and near IR light wavelengths. The photodetector drives a timing mark signal generator (80) to detect a sudden increase in yellow (red plus green) light, which indicates to the display controller that filter segment R has just rotated into the optical path.

Growing community of inventors

Portland, OR, United States of America

Steven E Stark