Compact sized optical projection system

• US 5,612,814 A
• Filed: 08/24/1995
• Issued: 03/18/1997
• Est. Priority Date: 08/24/1994
• Status: Expired due to Fees

• Current Assignee: Dongbu Daewoo Electronics Corporation (Dayou Holdings Co.,Ltd.)
• Original Assignee: Daewoo Electronics Company Limited (Dayou Holdings Co.,Ltd.)
• Inventors: Yang, Jin-Se
• Primary Examiner(s): Epps, Georgia Y.
• Assistant Examiner(s): BEY, DAWN MARIE
• Application Number:
  US08/518,871
• Time in Patent Office: 572 Days
• Field of Search: 359/212, 359/213, 359/214, 359/223, 359/224, 359/247, 359/259, 359/290, 359/291, 359/292, 359/295, 359/302, 359/316, 359/318, 359/846, 359/847, 359/848, 359/849, 359/850 , 359/851, 359/852, 359/853, 359/854, 359/855, 359/856, 359/857, 348/755, 348/756, 348/771
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0858 the reflecting means being moved or deformed by piezoelectric means

Abstract

A compact sized optical projection system capable of displaying an image of M×N pixels in various sizes, wherein M and N are integers, includes a light source, a source stopper, a source lens, a total reflection mirror, an array of M×N actuated mirrors, a projection stopper, a projection lens, a projection screen and an array of M×N pixel filters, wherein the array of M×N pixel filters includes a plurality of sets of R pixel filter, G pixel filter and B pixel filter, and each of the sets is repeated both in a horizontal and a vertical directions, and each of the pixel filters is capable of transmitting only one of the primary light beams.

Claims

1. An optical projection system capable of displaying an image of M×

N pixels, wherein M and N are integers, comprising;

a light source for emitting a white light, wherein the white light consists of a first, a second and a third primary light beams, each of the primary light beams being one of the primary colors;

an array of M×

N actuated mirrors for changing an optical path of each of the primary light beams reflected therefrom in response to an electric signal, wherein each of the actuated mirrors includes a pedestal, an actuator cantilevered from the pedestal and a mirror formed on top of the actuator, and the mirror in each of the actuated mirrors has a bending portion and an unbending portion, the unbending portion referring to a portion of the mirror on top of a portion of the actuator directly cantilevered on the pedestal, and each of the actuators is made of a piezoelectric or an electrostrictive material which deforms in response to the electric signal applied thereto;

a source stopper, provided with a light transmitting portion having a specific configuration and a light stopping portion and being placed in front of the light source, for shaping the white light from the light source into a predetermined configuration;

a source lens, disposed between the source stopper and the light source, for focussing the white light onto the source stopper;

an optical means for reflecting the white light from the source stopper to the array of M×

N actuated mirrors at a predetermined angle;

a field lens located between the optical means and the array of M×

N actuated mirrors, wherein the field lens is used for collimating the white light reflected from the optical means onto the array of M×

N actuated mirrors and for refocussing each of the primary light beams reflected from each of the actuated mirrors in the array;

an array of M×

N pixel filters, disposed between the field lens and the array of M×

N actuated mirrors, each of the pixel filters being capable of transmitting only one of the primary light beams, wherein each of the primary light beams transmitted through the array of M×

N pixel filters impinges onto a corresponding actuated mirror in the array and each of the primary light beams reflected by each of the actuated mirrors impinges onto the field lens through the array of M×

N pixel filters to thereby produce a packet of reflected primary light beams;

a projection screen being placed in front of the array of M×

N actuated mirrors for displaying an image made of the M×

N number of pixels thereon;

a projection stopper located between the optical means and the projection screen, provided with a light transmitting portion and a light stopping portion for passing a predetermined amount from the packet of reflected primary light beams refocussed by the field lens to thereby produce a packet of modulated primary light beams; and

a projection lens for projecting the packet of modulated primary light beams from the projection stopper onto the projection screen.

2. The optical projection system of claim 1, wherein the array of M×

N pixel filters includes a plurality of sets of R pixel filter, G pixel filter and B pixel filter, and each of the sets is repeated both in a horizontal and a vertical directions.

3. The optical projection system of claim 1, wherein each of the pixel filters is capable of transmitting only one of the primary light beams.

4. The optical projection system of claim 3, wherein each of the sets is of a perfect square.

5. The optical projection system of claim 3, wherein each of the pixel filters includes a dichroic coating, die coating or pigment coating.

6. The optical projection system of claim 5, the dichroic coating is made of a dielectric material.

7. The optical projection system of claim 2, wherein the array of M×

N pixel filters further includes a black matrix having a plurality of diffusion bands, each of the diffusion bands separating the columns of the pixel filters in the array.

8. The optical projection system of claim 7, wherein each of the diffusion bands in the black matrix has the same width as the unbending portion in each of the actuated mirrors.

9. The optical projection system of claim 7, each of the diffusion bands in the black matrix is aligned along the column direction of the array of M×

N actuated mirrors.

10. The optical projection system of claim 7, wherein each of the diffusion bands in the black matrix is made of a light reflective material.

11. The optical projection system of claim 10, wherein the light reflective material is chromium.