Projection display device

• US 20020176055A1
• Filed: 05/20/2002
• Published: 11/28/2002
• Est. Priority Date: 05/22/2001
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: De Vaan, Adrianus Johannes Stephanes Maria, Vanlier, Gerardus Johannes Josephus
• Granted Patent: US 6,702,446 B2
• Time in Patent Office: Days
• US Class Current: 353/31
• CPC Class Codes: H04N 9/3117 by using a sequential colour filter producing two or more colours simultaneously, e.g. by creating scrolling colour bands

Abstract

The invention relates to a projection display device comprising an illumination system having a light source and an optical guiding means for providing an illumination beam, an image display system comprising a display panel for modulating the illumination beam with image information and projecting the image on a screen, and color filter means provided on a wheel, rotatable mounted at its hub, for transmitting colored portions of the illumination beam for illuminating the display panel. In order to improve the efficiency of the projection display device, the color filter means comprises adjacent spiral-shaped filter portions for simultaneously illuminating portions of the display panel by the colored portions of the illumination beam so that the portions of the display panel are consecutively illuminated by the colored portions of the illumination beam.

Claims

1. A projection display device comprising

an illumination system having a light source and an optical guiding means for providing an illumination beam,

color filter means provided on a wheel, for transmitting colored portions of the illumination beam for illuminating the display panel, and

an image display system having a display panel for modulating the colored portions of the illumination beam with image information and projecting an image on a screen, characterized in that the color filter means comprises adjacent spiral-shaped filter portions for simultaneously illuminating portions of the display panel by the colored portions of the illumination beam so that the portions of the display panel are consecutively illuminated by the colored portions of the illumination beam.

2. A projection display device as claimed in claim 1, characterized in that the spiral-shaped portions extend from a first radius to a second radius of the wheel, the second radius being larger than the first radius, in which the first and second radii depend on the size of the display panel.

3. A projection display device as claimed in claim 1, characterized in that the spiral-shaped filter portions have an identical shape.

4. A projection display device as claimed in claim 1,2 or 3, characterized in that the spiral-shaped filter portions are arranged to transmit red, green and blue light, respectively.

5. A projection display device as claimed in claim 1,2 or 3, characterized in that the spiral-shaped filter portions are arranged to transmit red, green, blue and white light, respectively.

6. A projection display device as claimed in claim 2 characterized in that a cross-section in a radial direction of a spiral-shaped portion of a color selected from the group of red, green, blue and white extends from the first radius to the second radius of the wheel.

7. A projection display device as claimed in claim 6, characterized in that the projection display device is provided with a control means for providing the light source with a square-wave current for supplying a constant power to the light source and for imposing an arc-stabilisation pulse on the square-wave current for each change of polarity of the square-wave current, the control means being arranged to synchronise the occurrence of the arc-stabilisation pulse with the occurrence in the illumination beam of a maximum cross-section in the radial direction of the spiral-shaped portion having the selected color.

8. A projection display device as claimed in any one of the preceding claims, characterized in that the spiral-shaped filter portions comprise a dichroic filter.

9. A projection display device as claimed in claim 8, characterized in that the projection display device comprises light recycle means for re-using light from the dichroic filter.

10. A projection display device as claimed in claim 1, characterized in that the color filter wheel comprises a cholesteric color filter.

11. A projection display device as claimed in any one of the preceding claims, characterized in that the projection display device is provided with a transmissive image display panel or a reflective image display panel.