POLARIZATION CONVERSION ASSEMBLY AND SINGLE-IMAGER MICRO PROJECTION ENGINE

1 . A polarization conversion assembly, comprising:

a light source adapted to induce a collimated illumination beam forwards along a first direction;

a planar polarization beam splitter configured in an included facing angle α close to 45 degree with the first direction, and adapted to transmit a first polarization portion of the collimated illumination beam in first polarization state and reflect a second polarization portion of the collimated illumination beam in second polarization state perpendicular to first polarization state as a reflected second polarization portion in second polarization state along a second direction perpendicular to the first direction; and

a reflective quarter wave composite plate configured in parallel to and facing the planar polarization beam splitter forwards along the first direction, and adapted to reflect while polarization rotating by 90-degree from second polarization state to first polarization state, the reflected second polarization portion as a converted second polarization portion in first polarization state along the first direction.

2 . The polarization conversion assembly according to claim 1 , wherein the planar polarization beam splitter is adherently sandwiched between a first side-face of a transparent triangular prism and a first side-face of a transparent four-side polygon.

3 . The polarization conversion assembly according to claim 2 , wherein the reflective quarter wave composite plate is adhered to a second side-face opposite and parallel to the first side-face of the transparent four-side polygon.

4 . The polarization conversion assembly according to claim 2 , wherein the transparent triangular prism and the transparent four-side polygon are made from any one or combination of glasses, silicone and solid transparent organic materials comprising polycarbonates and PMMA.

5 . The polarization conversion assembly according to claim 1 , wherein the light source is generated by any one or combination of arc lamps, tungsten lamps, halide lamps, electromagnetic ballast, light emitting diodes and lasers.

6 . The polarization conversion assembly according to claim 1 , wherein the planar polarization beam splitter is either a multilayer polarizing beam splitting film or a wire grid polarizing plate.

7 . A single-imager micro projection engine, comprising:

the polarization conversion assembly of the claim 1 ;

a reflective polarization modulation imager comprising a plurality of reflective modulation-imager pixels in a regularly tiled planar arrangement perpendicular to the collimated illumination beam, facing the planar polarization beam splitter opposite to the light source, and adapted to receive q first polarization portion in first polarization state and a converted second polarization portion in first polarization state, and provide a modulated illumination of continued images in second polarization state; and

a projection lens system configured opposite to the reflective quarter wave composite plate relative to the planar polarization beam splitter, and adapted to allow the projection illumination of continued images which is formed after the polarization conversion assembly reflects the modulated illumination of continued images to lead through the projection lens system and project to a projection screen.

8 . The single-imager micro projection engine according to claim 7 , further comprising:

an imaging polarization beam splitter adapted to receive the first polarization portion of the collimated illumination beam and the converted second polarization portion from the planar polarization beam splitter, transmit the first polarization portion and the converted second polarization portion to the reflective polarization modulation imager, and reflect the modulated illumination of continued images in second polarization state from the reflective polarization modulation imager to the projection lens system.

9 . The single-imager micro projection engine according to claim 8 , wherein the reflective polarization modulation imager comprises a second transmissive quarter wave plate and a reflective intensity modulation imager panel.

10 . The single-imager micro projection engine according to claim 9 , wherein the reflective intensity modulation imager panel comprises a micro electrical-mechanical diffractive pixel array or a Galvanic light valve array in a regularly tiled planar arrangement.

11 . The single-imager micro projection engine according to claim 8 , wherein the reflective polarization modulation imager is a liquid crystal on silicon imager.

12 . The single-imager micro projection engine according to claim 8 , further comprising means for adjusting and balancing the first polarization portion and the converted second polarization portion received by the reflective polarization modulation imager.

13 . The single-imager micro projection engine according to claim 12 , wherein the means is adapted to electrically instruct the reflective polarization modulation imager upon measuring and calibrating, to adjust and balance reflected light outputs between the first half facing area receiving the first polarization portion and the second half facing area receiving the converted second polarization portion.

14 . The single-imager micro projection engine according to claim 13 , wherein the means is adapted to apply optical compensation to the first half facing area.

15 . The single-imager micro projection engine according to claim 14 , wherein the means is adapted to reduce intensity of the first polarization portion before applying the optical compensation to the first half facing area.