Patent ID: 6375330
Filing Date: 2002-04-23
Classification: H04N

Abstract:
An image projection engine apparatus comprising:a light source; a reflector that collects and condenses light emitted by said light source into a first focus of light; a mirror that redirects said first focus of light; a compander positioned to receive said first focus of light, said compander comprising an elongate member having an entrance face and an exit face oppositely opposed from said entrance face, said entrance face comprising a quadrilateral having a fixed aspect ratio, said entrance face having a first surface area, said exit face comprising a quadrilateral having said fixed aspect ratio and a second surface area, said second surface area being greater than said first surface area, said compander outputting a telecentric light beam, a first polarizing beamsplitter cube for receipt of said telecentric light beam, said first polarizing beamsplitter cube oriented such that it outputs a telecentric light beam having a first polarization; a condenser that receives said telecentric light beam having said first polarization state from said first polarizing beamsplitter cube and focuses said telecentric light beam along a first optical axis; a dichroic mirror disposed at a substantially forty-five degree angle with respect to said first optical axis, said first dichroic mirror adapted to split said light beam into a green light beam substantially along a second optical axis and a magenta light beam substantially along said first optical axis, said magenta beam having a red component and a blue component; a prism assembly, said prism assembly comprising: a first dichroic trimming mirror positioned substantially perpendicular to said second optical axis; a second polarization beamsplitter cube, said second polarization beam splitter cube comprising a first beam splitting hypotenuse which reflects first polarization green light along a third optical axis and transmits second polarization green light along said second optical axis; a first reflective liquid-crystal-on-silicon semiconductor light valve imaging device affixed to said second polarization beamsplitter cube and being substantially perpendicular to said third optical axis, said first reflective liquid-crystal-on-silicon semiconductor light valve imaging device reflecting green light towards said first beam splitting hypotenuse along said third optical axis, said first beam splitting hypotenuse reflecting first polarization green light along said second optical axis and transmitting second polarization green light along said third optical axis; a first half-wave retarder affixed to said second polarization beamsplitter cube and being substantially perpendicular to the third optical axis; a second dichroic trimming mirror arranged substantially perpendicularly to said first optical axis; a second half-wave retarder affixed to said second dichroic trimming mirror, said second half-wave retarder being substantially perpendicular to said first optical axis, said second half-wave retarder switching first polarization red light to said second polarization; a third polarization beamsplitter cube, said third polarization beam splitter cube comprising a second beam splitting hypotenuse which reflects first polarization light along a fourth optical axis and transmits second polarization light along said first optical axis; a second reflective liquid-crystal-on-silicon semiconductor light valve imaging device affixed to said third polarization beamsplitter cube and being substantially perpendicular to said first optical axis, said second reflective liquid-crystal-on-silicon semiconductor light valve imaging device reflecting red light towards said second beam splitting hypotenuse along said first optical axis, said second beam splitting hypotenuse reflecting first polarization red light along said fourth optical axis and transmitting second polarization red light along said first optical axis; a third reflective liquid-crystal-on-silicon semiconductor light valve imaging device affixed to said third polarization beamsplitter cube and being substantially perpendicular to said fourth optical axis, said third reflective liquid-crystal-on-silicon semiconductor light valve imaging device reflecting blue light back towards said second beam splitting hypotenuse along said fourth optical axis, said second beam splitting hypotenuse reflecting first polarization blue light along said first optical axis and transmitting second polarization blue light along said fourth optical axis; a third half-wave retarder affixed to said third polarization beamsplitter cube that is substantially perpendicular to said fourth optical axis, said third half-wave retarder switching said first polarization red light to said second polarization; said first reflective liquid-crystal-on-silicon semiconductor light valve imaging device, said second reflective liquid-crystal-on-silicon semiconductor light valve imaging device and said third reflective liquid-crystal-on-silicon semiconductor light valve imaging device each comprising an active imaging area having substantially said fixed aspect ratio and substantially said second surface area; and a fourth polarization beamsplitter cube affixed to said first half-wave retarder and said third half-wave retarder such that said third optical axis is substantially perpendicular to said fourth optical axis, said fourth polarization beam splitter cube comprising a third beam splitting hypotenuse which reflects first polarization light along said third optical axis and transmits second polarization light along said fourth optical axis.