Reflective LCD projector

• US 6,755,539 B2
• Filed: 12/06/2002
• Issued: 06/29/2004
• Est. Priority Date: 06/28/2000
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Brennesholtz, Matthew S.
• Primary Examiner(s): Adams, Russell
• Assistant Examiner(s): Cruz, Magda
• Application Number:
  US10/313,692
• Publication Number:
  US 20030133084A1
• Time in Patent Office: 571 Days
• Field of Search: 353/98, 353/33, 353/34, 353/37, 353/97, 353/99, 349/7, 349/67
• US Class Current: 353/98
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10

Abstract

An apparatus for projecting an image includes a light source, a polarization modulator, a projection lens, and a mirror. The mirror is positioned between the light source and the modulator and blocks a cross-sectional portion of the light from the light source from reaching the modulator. Light from the light source that reaches the modulator has its polarization modulated in accordance with a video signal to be displayed to produce a modulated signal corresponding to the video signal. The modulated light signal is reflected from the mirror into a projection lens.

Claims

1. An apparatus for projecting an image comprising:

a light source that produces light;

a modulator able to modulate polarization of the light in accordance with a video signal to be displayed to produce a modulated light signal corresponding to the video signal;

a projection lens; and

a mirror positioned between the light source and the modulator so that it blocks a cross-sectional portion of the light of the light source from reaching the modulator, and reflects the modulated light signal into the projection lens.

2. The apparatus of claim 1 wherein said cross-sectional portion of said light blocked by said mirror is substantially circular.

3. A method of producing an image for display comprising the steps of:

directing a light source toward a reflective LCD matrix;

modulating polarization associated with said light in a manner that is indicative of a video signal to be displayed to produce a modulated light signal;

reflecting said modulated light signal back to a mirror that is positioned between said light source and said LCD matrix so as to block a cross-sectional portion of the light of the light source from reaching the reflective LCD matrix; and

further reflecting said modulated light off of said mirror and through a projection lens.

4. The method of claim 3 wherein said light is modulated by at least three different modulators, each one of which modulates light of a different color.

5. The method of claim 4 wherein said mirror is substantially elliptical in shape.

6. The method of claim 4 wherein the mirror is curved.

7. A method of producing an image using a reflective LCD and a light source, the method comprising the steps of transmitting light onto the reflective LCD device, and modulating the light in accordance with a video signal indicative of the image to be displayed, parallel columns of light being transmitted to the reflective LCD device along a path that is interrupted with a reflecting mirror such that a cross-sectional portion of said light is blocked from reaching the LCD, and reflecting a portion of light not so blocked and which thus reaches the reflective LCD back onto the reflecting surface of said mirror for transmission to a projection lens element.

8. The method of claim 7 wherein said light is also transmitted through an X-cube.

9. The method of claim 7 wherein the light is modulated by changing its polarity, and wherein said modulated light is transmitted through a polarizer.