LCD projection system with polarization doubler

Claim 2

A projector system comprising: lamp means to generate light; collector means to gather and re-direct the generated light; a light pipe having an entrance pupil, an exit pupil, a center section and an optical axis, the light from the collector means being directed on the entrance pupil; a Liquid Crystal Display (LCD) image forming means to form an image and having an image gate, the exit pupil directing the light on the image gate; and a projector lens; characterized in that a Polarizing Beam Splitter (PBS) is positioned between the light pipe and the LCD image gate and that the light pipe is hollow, not filled with a dielectric, with mirror walls and tapered in shape with the entrance pupil having an area whose ratio to the area of a cross-section perpendicular to the optical axis of the center section is at least 1.5:1; and wherein the PBS comprises a single rectangular input face having an aspect ratio of 1/2 W:H and a rectangular output face having an aspect ratio of H:W where W is width and H is height.

Claim 3

A projector system comprising: lamp means to generate light; collector means to gather and re-direct generated light; a light pipe having an entrance pupil, an exit pupil, a center section and an optical axis, the light from the collector means being directed on the entrance pupil; a Liquid Crystal Display (LCD) image forming means to form an image and having an image gate, the exit pupil directing the light on the image gate; and a projector lens; characterized in that a Polarizing Beam Splitter (PBS) is positioned between the light pipe and the LCD image gate and that the light pipe is hollow, not filled with a dielectric, with mirror walls and tapered in shape with the entrance pupil having an area whose ratio to the area of a cross-section perpendicular to the optical axis of the center section is at least 1.5:1; and wherein the image gate is rectangular and has an aspect ratio of width W to height H (W:H) and the light pipe exit pupil is rectangular with an aspect ratio of W/2:H.

Claim 4

A projector system comprising: lamp means to generate light; collector means to gather and re-direct generated light; a light pipe having an entrance pupil, an exit pupil, a center section and an optical axis, the light from the collector means being directed on the entrance pupil; a Liquid Crystal Display (LCD) image forming means to form an image and having an image gate, the exit pupil directing the light on the image gate; and a projector lens; characterized in that a Polarizing Beam Splitter (PBS) is positioned between the light pipe and the LCD image gate and that the light pipe is hollow, not filled with a dielectric, with mirror walls and tapered in shape with the entrance pupil having an area whose ratio to the area of a cross-section perpendicular to the optical axis of the center section is at least 1.5:1; and wherein the image gate is rectangular and has an aspect ratio of width W to height H (W:H) and the light pipe exit pupil is rectangular with an aspect ratio of W/2:H.

Claim 5

A projector system comprising: lamp means to generate light; collector means to gather and re-direct the generated light; a light pipe having an entrance pupil an exit pupil a center section and an optical axis, the light from the collector means being directed on the entrance pupil; a Liquid Crystal Display (LCD) image forming means to form an image and having an image gate, the exit pupil directing the light on the image gate; and a projector lens; characterized in that a Polarizing Beam Splitter (PBS) is positioned between the light pipe and the LCD image gate and that the light pipe is hollow, not filled with a dielectric, with mirror walls and tapered in shape with the entrance pupil having an area whose ratio to the area of a cross-section perpendicular to the optical axis of the center section is at least 1.5:1; and wherein the collector means is a reflector with a central axis, mirror internal walls and is a compound reflector having at least two elliptical curves having two different eccentricities and is circular in cross-sections perpendicular to the axis.

Claim 6

A projector system comprising: lamp means to generate light; collector means to gather and re-direct the generated light; a light pipe having an entrance pupil an exit pupil a center section and an optical axis, the light from the collector means being directed on the entrance pupil; a Liquid Crystal Display (LCD) image forming means to form an image and having an image gate, the exit pupil directing the light on the image gate; and a projector lens; characterized in that a Polarizing Beam Splitter (PBS) is positioned between the light pipe and the LCD image gate and that the light pipe is hollow, not filled with a dielectric, with mirror walls and tapered in shape with the entrance pupil having an area whose ratio to the area of a cross-section perpendicular to the optical axis of the center section is at least 1.5:1; and wherein the collector means is a reflector with a central axis, mirror internal walls and is a compound reflector having at least two elliptical curves having two different eccentricities and is circular in cross-sections perpendicular to the axis.

Claim 7

A projector system as in claim 3 wherein the reflector is curved and concave in shape in profiles through the axis, and the profile curvature comprises at least two ellipses having different eccentricities and both eccentricities are in the range of 0.60-0.90.

Claim 8

A projector system comprising: an elliptical reflector having a central axis, the lamp being positioned at the reflector's axis; a metal halide arc lamp within the reflector and having an arc gap in the range of 1-6 mm; a hollow light pipe not filled with dielectric and having an optical axis, an entrance pupil, a rectangular exit pupil, a central section between the entrance and exit pupils, flat mirror interior reflecting walls of low expansion glass, and a tapered shape in which the entrance pupil is at least 50% larger than the area of a cross-section of the central section taken perpendicular to the optical axis; a cold mirror coating means coating the reflecting walls to reflect visible light and transmit infra-red light; a LCD (Liquid Crystal Display) panel; a Polarizing Beam Splitter (PBS) means positioned between the light pipe and the LCD panel to split unpolarized light from the light pipe into P and S polarized beams and to reverse the polarization of either the P or S beams and to combine the two beams side-by-side to form a single beam having one polarization; and a projector lens means to project images formed by the LCD panel onto a screen.

Claim 9

A projector system comprising: an elliptical reflector having a central axis, the lamp being positioned at the reflector's axis; a metal halide arc lamp within the reflector and having an arc gap in the range of 1-6 mm; a hollow light pipe not filled with dielectric and having an optical axis, an entrance pupil, a rectangular exit pupil, a central section between the entrance and exit pupils, flat mirror interior reflecting walls of low expansion glass, and a tapered shape in which the entrance pupil is at least 50% larger than the area of a cross-section of the central section taken perpendicular to the optical axis; a cold mirror coating means coating the reflecting walls to reflect visible light and transmit infra-red light; a LCD (Liquid Crystal Display) panel; a Polarizing Beam Splitter (PBS) means positioned between the light pipe and the LCD panel to split unpolarized light from the light pipe into P and S polarized beams and to reverse the polarization of either the P or S beams and to combine the two beams side-by-side to form a single beam having one polarization; and a projector lens means to project images formed by the LCD panel onto a screen.

Claim 10

A light engine for an optical projector system using a rectangular Liquid Crystal Display (LCD) panel having an aspect ratio of Width:Height (W:H), the light engine comprising: lamp means to generate light; collector means to collect and direct the generated light; and a light pipe having an entrance pupil and an exit pupil; characterized in that: a Polarizing Beam Splitter (PBS) is positioned between the light pipe and the LCD panel; the light pipe exit pupil has a rectangular face and an aspect ratio of W/2:H and the PBS generates a uni-polarized beam which is rectangular in cross-section and having an aspect ratio of W:H.

Claim 11

A light engine for an optical projector system using a rectangular Liquid Crystal Display (LCD) panel having an aspect ratio of Width:Height (W:H), the light engine comprising: lamp means to generate light; collector means to collect and direct the generated light; and a light pipe having an entrance pupil and an exit pupil; characterized in that: a Polarizing Beam Splitter (PBS) is positioned between the light pipe and the LCD panel; the light pipe exit pupil has a rectangular face and an aspect ratio of W/2:H and the PBS generates a uni-polarized beam which is rectangular in cross-section and having an aspect ratio of W:H.

Claim 12

A light engine as in claim 6 wherein the lamp means is a metal halide arc lamp having an arc gap in the range of 1-6 mm.

Claim 13

A projector system comprising: lamp means to generate light; a compound reflector having an optical axis to gather and direct the generated light; the reflector having a curvature whose cross-sections through the optical axis are segments of at least two different curves; a light pipe having an entrance pupil, a rectangular exit pupil reflective internal walls, a center section between the entrance and exit pupils, and an optical axis, the light from the reflector being directed on the entrance pupil, the light pipe being double tapered in shape with the entrance pupil and exit pupil each having a larger area than the area of a cross-section of the center section; a Liquid Crystal Display (LCD) panel means to form an image and an aspect ratio of W:H; a Polarizing Beam Splitter (PBS) having a rectangular input face with an aspect ratio of W/2:H positioned between the reflector and the LCD panel means; and a projector lens.

Claim 14

A projector system comprising: lamp means to generate light; a compound reflector having an optical axis to gather and direct the generated light; the reflector having a curvature whose cross-sections through the optical axis are segments of at least two different curves; a light pipe having an entrance pupil, a rectangular exit pupil reflective internal walls, a center section between the entrance and exit pupils, and an optical axis, the light from the reflector being directed on the entrance pupil, the light pipe being double tapered in shape with the entrance pupil and exit pupil each having a larger area than the area of a cross-section of the center section; a Liquid Crystal Display (LCD) panel means to form an image and an aspect ratio of W:H; a Polarizing Beam Splitter (PBS) having a rectangular input face with an aspect ratio of W/2:H positioned between the reflector and the LCD panel means; and a projector lens.

Claim 15

A projector system as in claim 8 wherein the lamp means is a plasma arc lamp having an arc gap in the range of 1-6 mm.

Claim 16

A projector system as in claim 8 wherein the lamp means is a metal halide arc lamp or an incandescent lamp.

Claim 17

A projector system as in claim 9 wherein the two different curves of the reflector are ellipses having two different eccentricities and with two different focal lengths which are ±2 mm from a central focal point.

Claim 18

A projector system as in claim 8 wherein the reflector has a mirror internal wall, a back closed end portion having an elliptical curve in profile with a first eccentricity and an open end portion having an elliptical curve in profile with a second eccentricity which is larger than the first eccentricity.

Claim 19

A projector system as in claim 8 wherein the light pipe is hollow, without a dielectric filling, and has flat walls of low expansion glass.

Claim 20

A projector system as in claim 8 wherein the entrance pupil is square, round or octagonal.

Claim 21

A projector system comprising: (a) a metal halide arc lamp having an arc gap in the range of 1-6 mm; (b) a reflector having a central axis, the lamp arc gap being along the reflector's axis; the reflector being circular in cross-sections perpendicular to the central axis and being curved in profile in at least two elliptical curves having different eccentricities; (c) a light pipe having an entrance pupil, a rectangular exit pupil, a center section between the entrance and exit pupils, an optical axis, and a tapered shape in which the entrance pupil is at least 50% larger than the area of a cross-section of a center section taken perpendicular to the optical axis; (d) a Polarizing Beam Splitter (PBS) means to receive unpolarized light from the light pipe exit pupil and convert it to uni-polarized light; (e) a LCD (Liquid Crystal Display) panel illuminated by uni-polarized light transmitted from the PBS; and (f) a projector lens means to project images formed by the LCD panel onto a screen.

Claim 22

A projector system comprising: (a) a metal halide arc lamp having an arc gap in the range of 1-6 mm; (b) a reflector having a central axis, the lamp arc gap being along the reflector's axis; the reflector being circular in cross-sections perpendicular to the central axis and being curved in profile in at least two elliptical curves having different eccentricities; (c) a light pipe having an entrance pupil, a rectangular exit pupil, a center section between the entrance and exit pupils, an optical axis, and a tapered shape in which the entrance pupil is at least 50% larger than the area of a cross-section of a center section taken perpendicular to the optical axis; (d) a Polarizing Beam Splitter (PBS) means to receive unpolarized light from the light pipe exit pupil and convert it to uni-polarized light; (e) a LCD (Liquid Crystal Display) panel illuminated by uni-polarized light transmitted from the PBS; and (f) a projector lens means to project images formed by the LCD panel onto a screen.

Claim 23

A projector system as in claim 15 wherein the elliptical curves each have a different focal point.