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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
First Claim
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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.

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