Optical projection system

• US 5,669,687 A
• Filed: 06/20/1996
• Issued: 09/23/1997
• Est. Priority Date: 10/31/1994
• Status: Expired due to Fees

• Current Assignee: Dongbu Daewoo Electronics Corporation
• Original Assignee: Daewoo Electronics (Government of South Korea)
• Inventors: Yang, Jin-Se
• Primary Examiner(s): DOWLING, WILLIAM C
• Application Number:
  US08/667,175
• Time in Patent Office: 460 Days
• Field of Search: 353/31, 353/34, 353/37, 353/97, 353/98, 353/99, 353/84, 348/771, 348/772, 348/764, 348/755
• US Class Current: 353/98
• CPC Class Codes: H04N 9/3108 by using a single electronic spatial light modulator

Abstract

An optical projection system includes a non-point white light source for emanating a white light, a source lens for focusing the white light, a source stopper having a source aperture for shaping the white light into a predetermined configuration, an optical means having a reflection surface for reflecting the white light, a field lens for collimating the white light, an array of M×N thin film actuated mirrors for changing the optical path of the white light reflected therefrom, a projection stopper having a projection aperture for passing a predetermined amount of the white light, a relay lens system having a plurality of lenses for modulating the size of the predetermined configuration of the white light, a RGB pixel filter for dividing the white light into the primary light beams, a projection lens for projecting the primary light beams and a projection screen for displaying an image made up of M×N number of pixels thereon. In the optical projection system, the RGB pixel filter is disposed between the projection stopper and the projection lens, and hence the white light only has to pass through the RGB pixel filter once, which will, in turn, prevent the lowering of the intensity of the white light and hence the optical efficiency of the system, and it will also cut down the amount of the white light that is reflected away, thereby reducing noises at the projection screen.

Claims

1. An optical projection system capable of displaying an image having pixels on a projection screen comprising:

means for emanating a white light, wherein the white light has a first, a second and a third primary light beams, each of the primary light beams being of one of the primary colors;

an array of thin film actuated mirrors, each of the thin film actuated mirrors in the array being capable of reflecting the white light and changing an optical path of the reflected white light therefrom;

a projection stopper, provided with a projection aperture, for passing a fraction of the reflected white light from each of the thin film actuated mirrors in the array through the projection aperture thereof, to thereby modulate the intensity of the reflected white light;

an RGB pixel filter for dividing the white light passing through the projection stopper into the primary light beams; and

a projection lens for projecting the primary light beams from the RGB pixel filter on the projection screen.

2. The optical projection system of claim 1, wherein the white light from the emanating means has a predetermined configuration.

3. The optical projection system of claim 1, further comprising a field lens which is used for colliminating the white light from the emanating means onto the array of thin film actuated mirrors and for focusing the reflected white light from each of the thin film actuated mirrors onto the projection stopper.

4. The optical projection system of claim 1, wherein the fraction of the reflected white light passing through the projection stopper is determined by the optical path thereof.

5. The optical projection system of claim 1, further comprising a relay lens system disposed between the projection stopper and the RGB pixel filter.

6. The optical projection system of claim 5, wherein the relay lens system is provided with a plurality of lenses.

7. The optical system of claim 3, further comprising a source stopper, provided with a source aperture, for passing a fraction of the white light from the emanating means to the field lens.

8. The optical projection of claim 7, wherein the source stopper and the projection stopper are positioned at the focal point of the field lens.

9. An optical projection system capable of displaying an image having pixels on a projection screen comprising:

means for emanating a white light, wherein the white light has a first, a second and a third primary light beams, each of the primary light beams being of one of the primary colors;

a source stopper, provided with a source aperture, for shaping the white light from said means emanating into a predetermined configuration;

an array of actuated mirrors type optical path changing means, each of the actuated mirrors in the array being capable of reflecting the white light and changing an optical path of the reflected white light therefrom;

a field lens for collimating the white light from said source stopper and for focusing the reflected white light from each of the actuated mirrors in the array;

a projection stopper, provided with a projection aperture, for passing a fraction of the reflected white light from each of the actuated mirrors in the array through the projection aperture thereof, to thereby modulate the intensity of the reflected white light;

a RGB pixel filter for dividing the white light passing through the projection stopper into the primary light beams; and

a projection lens for projecting the primary light beams from the RGB pixel filter on the projection screen,

wherein said source and projection stoppers are placed at the focal point of said field lens.

10. An optical projection system capable of displaying an image having pixels on a projection screen comprising:

a first optical light path, having means for emanating a white light, wherein the white light has a first, a second and a third primary light beams, each of the primary light beams being of one of the primary colors, a source stopper, provided with a source aperture, for shaping the white light from said emanating means into a predetermined configuration, and an array of actuated mirrors type optical path changing means, each of the actuated mirrors in the array being capable of reflecting the white light and changing an optical path of the reflected white light therefrom; and

a second optical light path, having a projection stopper, provided with a projection aperture, for passing a predetermined amount of the reflected light from said optical path changing means to modulate the intensity of the white light, a RGB pixel filter for dividing the white light passing through the projection stopper into the primary light beams, a projection lens for projecting the primary light beams from the pixel filter onto the projection screen.