KR20050103500A - Polarization recovery system using redirection - Google Patents

Abstract

A polarization recovery system includes a polarizing beam splitter transmitting light of a useful polarization in an output direction and reflecting light of a non-useful polarization in a first orthogonal direction substantially orthogonal to the output direction. An initial reflector may reflect the non-useful polarization light in a second orthogonal direction substantially orthogonal to the output direction and the first orthogonal direction, and a final reflector may reflect the non-useful polarization light in the output direction. The non-useful polarization light may be rotated substantially to light of the useful polarization by the initial and final reflectors.

Description

Polarization Recovery System Using Redirection

This application claims priority to U.S. Provisional Application No. 60 / 448,471, filed Feb. 21, 2003, and U.S. Provisional Application No. 60 / 469,393, May 12, 2003, which is incorporated herein by reference. It is included in the application. This application is part of a continuing application of patent application Ser. No. 10 / 347.522, filed Jan. 21, 2003, filed March 23, 2001, patent application Ser. No. 6,587,269.

The present invention relates to recovering light that is not useful in a projection system.

Projection displays work by projecting light onto a screen. This light is arranged in a pattern of color, contrast or a combination thereof. This pattern is observed by an observer who is already familiar with things such as letters or appearances, and the observer associates images with patterns and recognizes them by identifying them. This pattern may be formed in various ways. One way to form the patterns is to modulate a beam of light into a stream of information.

The polarized light can be modulated by filtering with a polarization filter. When the polarization of the polarizing filter matches that of the incident light, the polarizing filter generally passes the light. Liquid crystal display (LCD) imagers can be used to perform modulation with an LCD type projection display. The LCD imager may include pixels that can be modulated by changing their polarization to match or otherwise differ from the polarization of the incident light. The polarization of the selected pixel is changed when the LCD pixel is modulated, and when the light output from the imager is detected by another polarizer, the input light to the LCD imager is polarized in such a way that the selected pixel is dark. Depending on the presence of light the pattern can be projected on the screen. If the polarization of the pixel is modulated with information about the pattern familiar to the viewer, the viewer will be able to recognize the projected pattern on the screen.

One way to polarize light for an LCD imager is to use a polarizing beam splitter (PBS). Polarized light may be provided to an imaging system having a lens array, such as a fly's eye lens, and a polarizing beam splitter array. Parabolic reflectors can be used to focus light nearly parallel with a fly's eye lens. The beam will be divided into a plurality of sections by the lens array and each section will be refocused by the other lens array into a polarizing beam splitter array. However, a parabolic reflector can reduce the brightness of a light source such as, for example, an arc. In addition, the efficiency of the fly's eye lens repair system is critically limited by the placement of the two lens arrays and the polarization beam splitter array. In conclusion, a polarizing recovery system consisting of a parabolic reflector and fly's eye lens may not be suitable for sequential color single imager systems.

Elliptical reflectors can be used with light pipes and color wheels to produce continuous color and the like. However, such systems still require a polarization recovery system and do not address the inherent loss of brightness associated with elliptical reflectors. The light output from the polarization beam splitter array is then linearly polarized and focused to a target. Each polarizing beam splitter splits unpolarized light into beams with heterogeneous polarization. Only one of the beams will be the correct polarization input to the LCD imager after the light is polarized. The other beam will be inaccurately polarized and therefore not directly useful.

A polarization recovery system can be used to recover un useful polarized light by converting it into useful light with accurate polarization. Various methods have been developed for converting incorrectly polarized light into accurate polarized light to have a high degree of utility. One method, as shown in FIG. 1, is to transfer the light of the first polarized light 102 directly from the polarizing beam splitter 104 to the output 106, and output 106. The second polarized light 108 is reflected at an angle at, for example 90 °. The light of the second polarizing light 108 is then reflected and paralleled to the light of the first polarizing light 102 and guided to the output 106. A retarder plate 110, such as a quarter wavelength or half wavelength plate, is disposed in the optical path of the second polarizing light 108 and thus first polarizing light 102. By rotating, the output consists only of the first polarizing light 102.

The retarder plate rotates from one polarizing light to another polarizing light by slowing the speed of light in one plane, allowing the light in the plane of symmetry to pass relatively unobstructed. The rate at which light propagates through the medium is generally related to its wavelength. Thus, the degree to which light is delayed is also related to its wavelength. Because the retarder plate, which is applied to broadband light, passes some light in a wavelength range, some light is delayed more than others. In general, retarder plates are tailored to specific wavelengths. In particular, wavelengths longer or shorter than the fitted wavelength will not be completely rotated from the unusable polarized light to the correct polarized light. Thus, some light at wavelengths longer or shorter than the fitted wavelength will be lost or at least not recovered. In addition, the retarder plate is relatively expensive and inferior in reliability. Retarder plates make the polarization recovery system itself expensive and less reliable.

Although these systems are used industrially, component costs are expensive and they require very precise placement and optical design. As a result, there is a need for a system capable of performing polarization conversion with high efficiency, simple placement and low cost.

1 is a diagram illustrating a polarization recovery system.

2 is a diagram schematically illustrating a polarizing recovery system according to an embodiment of the present invention.

3A and 3B are diagrams illustrating a polarization recovery system used in one embodiment of the present invention.

4A and 4B are diagrams illustrating a polarization recovery system used in one embodiment of the present invention.

5 is a diagram illustrating a polarization recovery system used in an embodiment of the present invention.

6A-6C illustrate straight and tapered light pipes used in one embodiment of the present invention.

7A-7H are cross-sectional views of various light pipes used in one embodiment of the present invention.

8A to 8E illustrate various shapes of light pipes used in an embodiment of the present invention.

9 is a view showing a polarizing recovery device used in an embodiment of the present invention.

In a first aspect of the invention, a polarizing recovery system includes a polarizing beam splitter that conducts useful polarizing light in an output direction and reflects unused polarizing light in a first orthogonal direction substantially perpendicular to the output direction. An initial reflector disposed reflectively in the first orthogonal direction and reflecting the undesired polarized light in a second orthogonal direction that is orthogonal to the output direction and the first orthogonal direction, and in the second orthogonal direction And a final reflector disposed reflectively and reflecting the undesired polarized light in the output direction, wherein the unused polarized light is rotated into the useful polarized light by the initial and final reflectors.

In a second aspect of the invention, a method of recovering polarization comprises polarizing light into useful polarized light and unused polarized light, conducting the useful polarized light in an output direction, Reflecting the non-use polarized light in a first orthogonal direction orthogonal to and reflecting the non-use polarized light in a second orthogonal direction orthogonal to the output direction and the first orthogonal direction; And reflecting the unusable polarized light in the output direction.

In a third aspect of the invention, a polarization recovery system comprises means for polarizing light into useful polarized light and unused polarized light, means for conducting the useful polarized light in an output direction, and perpendicular to the output direction. Means for reflecting said unused light in a first orthogonal direction, means for reflecting said unused light in a second orthogonal direction orthogonal to said output direction and said first orthogonal direction, and said output in said output direction It may include means for reflecting light that is not useful.

It would be highly desirable if the unusable polarizing light could be recovered and used by causing its polarization to be converted to accurate or useful polarizing light. Since retarder plates make the polarization recovery system very expensive and less reliable, it may be highly desirable that the polarization recovery can be performed without depending on the use of the retarder plate. Polarization recovery would preferably be performed with broadband radiation. It would be desirable for the manufacture and assembly of the polarization recovery system to be relatively simple. It may be desirable to allow the polarization recovery system to use a color wheel as a single imager system.

2 illustrates a polarization recovery system 200 according to a first embodiment of the present invention. The polarization recovery system 200 can include a polarizing beam splitter 202, such as a multi-layer coated polarizing beam splitter or a wire-grid polarizing beam splitter. In one embodiment of the invention, the light input to the polarizing beam splitter 202 is obtained directly or indirectly from electromagnetic radiation, ie, the source 212 of light. The source of electromagnetic radiation 212 may be an xenon lamp, a metal halide lamp, an arc lamp such as a high intensity discharge (HID) lamp, a mercury lamp, or the like. In addition to the lamp as described above, a halogen lamp or a filament lamp may be used as the supply source.

Polarization recovery system 200 according to an embodiment of the present invention, as shown in Figures 2 and 5, the input light pipe (224), supercube (268) and output An output light pipe 232 may be provided. In some embodiments of the invention, the output light pipe 232 may be a homogenizer or an integrator or the like. The output of the input light pipe 224 may be coupled to the supercube 268 which is a prism combination. The input light pipe 224 may use total internal reflection (TIR) to propagate light to the supercube 268.

In some embodiments of the invention, the input light pipe 224, the output light pipe 232, or both the input light pipe and the output light pipes 224, 232 are tapered as shown in FIG. 6A. It may have a shape, a reduced taper shape as shown in FIG. 6B, or a straight line shape as shown in FIG. 6C. In addition, the cross-sectional shape of the input light pipe 224, the output light pipe 232, or both the input light pipe and the output light pipe 224, 232 is rectangular, circular, as shown in Figs. It may be triangular, rectangular, ladder, pentagonal, hexagonal or octagonal in shape. In addition, at least one of the input light pipe 224 and the output light pipe 232 is an optical fiber, a bundle of fibers, a bundle of molten fibers, a polygonal waveguide as shown in FIGS. 8A to 8E. Or a hollow light pipe.

Other embodiments of the invention are shown in FIGS. 3 and 4. The polarizing beam splitter 202 is used to provide unpolarized light with useful polarizable light 204 (see FIGS. 3A and 4A) having a first polarization 270 as shown in FIGS. 3A and 4A. As shown in 3b and 4b, it can be separated into non-use polarizing light 208 having a second polarization 272. The polarizing beam splitter 202 transmits useful polarizable light 204 in the output direction 206 and the non-use polarized light 208 is in a first orthogonal direction substantially perpendicular to the output direction 206. Reflected at (210). In one embodiment of the present invention, the first polarization 270 means s-polarized or horizontally polarized light and the second polarization is p-polarized or vertically polarized light. Can mean. In other embodiments of the invention, polarization planes may be applied in reverse.

Useful polarizing light 204 propagates through polarizing beam splitter 202 and is redirected by first output reflector 220 and second output reflector 222, as shown in FIGS. 3A and 4A, The polarization 270 exits from the second output reflector 222 unchanged. On the other hand, the unusable polarizing light 208 may pass through the polarizing beam splitter 202 and then be reflected by the original reflector 214 as shown in FIGS. 3B and 4B. The original reflector 214 reflects the unusable polarizing light 208 around an axis substantially perpendicular to the plane of its polarization 272, where the plane is an s-polarized or vertical polarized plane. . And the final reflector 218 reflects unpolarized light 208 in a direction parallel to the output direction 206. The inclined surface of the original reflector 214 is rotatable at an angle of 90 ° relative to the final reflector 218. Unusable polarized light 208 is referred to as still unusable polarized light 208 for tracking purposes, but this soon becomes useful polarized light, which is not useful polarized light 208. This is because the polarization plane of is vertically or p-polarized to match the polarization plane of the useful polarization light 204. In one embodiment of the present invention, the useful polarizing light 204 and the unusing polarizing light 208 are combined and homogenized in the output light pipe 232.

In one embodiment of the present invention, the first output reflector 220 may be arranged to be reflective in the output direction 206. The first output reflector 220 may reflect useful polarizing light 204 in a second orthogonal direction 216. In another embodiment of the invention, the first output reflector 220 may be a mismatched impedance, such as a prism, a rectangular prism, or a mirror. In one embodiment, the first output reflector 220 may have a coating that transmits a predetermined portion of the electromagnetic radiation spectrum. The coating may serve to remove non-visible light before it is combined in the imager. In some embodiments of the invention, the predetermined portion of the electromagnetic radiation spectrum may be infrared, visible light, a predetermined band of wavelengths of light, a specific color of light, or a combination thereof. In another embodiment of the present invention, the coating may reflect infrared light, visible light, a predetermined band of wavelengths of light, a specific color of light, or any combination thereof.

According to one embodiment of the present invention, as shown in FIG. 3A, the second output reflector 222 may be arranged to be reflective in the second orthogonal direction 216. The second output reflector 222 may reflect useful polarizing light 204 in the output direction 206. According to another embodiment of the present invention, as shown in FIG. 4B, the second output reflector 222 may be disposed to be reflective in the output direction 206. The second output reflector 222 reflects the unusable polarized light 208 in the second orthogonal direction 216. In some embodiments of the invention, the second output reflector 222 may be a mismatched impedance, such as a prism, a rectangular prism, or a mirror. In one embodiment, the second output reflector 222 may have a coating that transmits a predetermined portion of the electromagnetic radiation spectrum. The coating may serve to remove invisible invisible light before it is combined in the imager. In some embodiments of the invention, the predetermined portion of the electromagnetic radiation spectrum may be infrared, visible light, a predetermined band of wavelengths of light, light of a specific color, or a combination thereof. In other embodiments, the coating may reflect infrared light, visible light, a predetermined band of wavelengths of light, light of a particular color, or any combination thereof.

In one embodiment of the present invention, the initial reflector 214 may be arranged to be reflective in the first orthogonal direction 210. The original reflector 214 may reflect unused polarized light 208 in a second orthogonal direction 216 substantially perpendicular to the output direction 206 and the first orthogonal direction 210. In some embodiments of the invention, the original reflector 214 may be a mismatched impedance, such as a prism, a rectangular prism, or a mirror. Mismatched impedances can echo waves, such as electromagnetic waves, in an echo manner. The mismatched impedance may reflect, for example, a portion of the wave or a predetermined range of wavelengths and transmit other portions or other wavelengths of the wave.

In one embodiment of the invention, the original reflector 214 may have a coating that transmits a predetermined portion of the electromagnetic radiation spectrum. The coating may serve to remove invisible invisible light before it is combined in the imager. In some embodiments of the present invention, the predetermined portion of the electromagnetic radiation spectrum may be red light, visible light, a predetermined band of wavelengths of light, light of a specific color, or a combination thereof. In another embodiment of the present invention, the coating may reflect infrared light, visible light, a predetermined band of wavelengths of light, light of a particular color, or any combination thereof.

In one embodiment of the present invention, the final reflector 218 may be disposed to be reflective in the second orthogonal direction 216. The final reflector 218 may reflect unusable polarized light 208 in the output direction 206. In some embodiments of the invention, the final reflector 218 may be a mismatched impedance, such as a prism, a rectangular prism, or a mirror. In one embodiment of the invention, the final reflector 218 may have a coating that transmits a predetermined portion of the electromagnetic radiation spectrum. The coating may serve to remove invisible invisible light before it is combined in the imager. In some embodiments of the invention, the predetermined portion of the electromagnetic radiation spectrum may be infrared, visible light, a predetermined band of wavelengths of light, light of a specific color, or a combination thereof. In another embodiment of the present invention, the coating may reflect infrared light, visible light, a predetermined band of wavelengths of light, light of a particular color, or any combination thereof.

In one embodiment of the present invention, the polarization 272 of the unusable polarizing light 208 is the polarization 270 of the polarizing light 204 useful by the initial and final reflectors 214, 218. Can be rotated to In addition, the first orthogonal direction 206 and the second orthogonal direction 216 may lie on the plane of the polarization 272 of the polarizing light 208 which is not substantially useful. This basic block is such that the polarization 272 of the unusable polarizing light 208 is converted to the polarization 270 of the useful polarizing light 204 and redirected in the output direction 206. Thus, as described above, it is possible to reflect and redirect the unusable polarizing light 208 from the polarizing beam splitter 202.

According to another embodiment of the present invention, as shown in FIG. 9, the initial reflector 214 is not useful for a polarization around an axis where the final reflector 218 is substantially orthogonal to the plane of polarization 272. Compared to reflecting light 208, it is possible to reflect unpolarized light 208 around the axis in the plane of polarization 272 so that unusable polarized light 208 is polarized ( 270). Light from the final reflector 218 passes through a spacer 246 such that the unpolarized, horizontally polarized light 208, which is not useful, exits in the same plane as the useful polarizable light 204. . The two outputs are combined and homogenized in the output light pipe 232 and have numerical apertures and shapes that are converted to the required numerical aperture (NA) and shape at the output face. In one embodiment of the invention, the output light pipe 232 may use Total Internal Reflection (TIR) to propagate light to its output.

In one embodiment, the useful polarizing light 204 is redirected to the output direction by the final reflector 218 and then exits the polarizing beam splitter 202 in a different direction than the unpolarizing polarizing light 208. Can be. In one embodiment, as shown in FIG. 3A, the first output reflector 220 and the second output reflector 222 are useful polarizing light 204 in the same direction as the non-useable polarizing light 208. Can be used to redirect. In another embodiment, as shown in FIG. 4A, the first output reflector 220 redirects the useful polarizing light 204, while as shown in FIG. 4B, the second output reflector 222. Redirects the unusable polarizing light 208 in the same direction as the useful polarizing light 204. In either case, spacers 246 may be used to cause useful polarizable light 204 to exit on the same surface as non-useable polarized light 208. By doing so, the useful polarizable light 204 and the unusable polarized light 208 can be easily coupled in the output light pipe 232.

In one embodiment, the supercube 268 may be comprised of a polarizing beam splitter 202 and reflectors 214, 218, 220, 222. Light can propagate through these optical elements by total reflection. The surface of the optical elements can be optically polished to promote total reflection. In one embodiment, the optical material used for the reflectors 214, 218, 220, 222 may have a high refractive index to promote total reflection of skew rays. In one embodiment, the input and output sides of the optical device may be coated with an anti-reflective (AR) coating to minimize Fresnel reflection losses.

In one embodiment, reflectors 214, 218, 220, 222 may be made of optical glass, such as SF11 (n = 1.785). In other embodiments, reflectors 214, 218, 220, 222 may be made of optical glass such as BK7 (n = 1.517). However, in this embodiment, light rays will begin to leak on the walls, in particular on the diagonal walls of the reflectors 214, 218, 220, 222.

In one embodiment, spacers 246 may be used in combination with reflectors 214, 218, 220, 222 to form large cubic shapes for easy packaging. In one embodiment, the spacer 246 may be a cube. In one embodiment, each reflector 214, 218, 220, 222 may be combined with an auxiliary spacer 246, such as a right angle spacer, to form a small cube. In one embodiment, eight small cubes may form the supercube 268. In one embodiment, reflectors 214, 218, 220, 222 and spacers 272 are stacked together to form a supercube 268. In one embodiment, the elements can be adhered to each other by an adhesive material. In another embodiment, the elements can be secured to each other by mechanical holder means. This structure is simple, but losses can be minimized.

In some embodiments, a gap is formed in the reflector 214, 218, 220, 222 or polarizing beam splitter 202 between any two input and output light pipes 224 and 232, so that total reflection To promote and reduce losses. In one embodiment, the input light pipe 224, the reflectors 214, 218, 220, 222, and the output light pipe 232 may be separated by a small air gap.

In one embodiment, as shown in FIG. 5, the supercube 268 may be made of individual elements. In one embodiment, some of the elements may be combined into a single unit. In one embodiment, for example, two prisms may be combined into a single prism. In this embodiment, the pair of reflectors 214, 218, 220, 222 may be combined through a manufacturing process, for example a glass molding process. In other embodiments, the two prisms may be glued to each other to form a single unit. In one embodiment, two prisms may be combined with half of the polarization beam splitter 202 to form a single unit. In such embodiments, the entire PCS system may consist of two elements with spacers 246. In other embodiments, one prism may be combined with the spacer 246. In another embodiment, the system may be separate from the polarization beam splitter 202 and consist of two elements. In this embodiment, the cost is minimized.

In one embodiment, polarizing beam splitter 202 and reflectors 214, 218, 220, 222 may be substantially cubic. In one embodiment, polarizing beam splitter 202 and reflectors 214, 218, 220, 222 may be substantially similar in size in all respects except for the hypotenuse of the reflector. In this embodiment, the output side of the input light pipe 224 may be rectangular, and the input side of the output light pipe 232 may be a rectangle having an aspect ratio of 2: 1. The non-cube shape can be supplemented so that the input side of the output light pipe 232 has a ratio different from 2: 1, even if the coupling loss is as large as possible.

In some embodiments, the input and output light pipes 224, and 232 and the reflectors 214, 218, 220, 222, or polarizing beam splitter 202 are coated with an antireflection (AR) coating to increase efficiency. Can be. In some embodiments, the input and output light pipes 224 and 232 may be in the form of increased or decreased tapered, depending on the needs of the application. Reflectors 214, 218, 220, and 222 may be reflectors coated to suit high angle light. In addition to the above, the supercube 268 may be used in various shapes.

In one embodiment, the input light pipe 224 may be disposed adjacent to the input 226 of the polarizing beam splitter 202. In such an embodiment, the input light pipe 224 may have an input surface 228 and an output surface 230. In some embodiments, input light pipe 224 may be made of quartz, glass, plastic, or acrylic. In some embodiments, input light pipe 224 may be a tapered light pipe (TLP) or a straight light pipe (SLP). In some embodiments, the shape of the input surface 228 may be planar, convex, concave, donut or spherical. The surface of the input light pipe 224 may be coated to maintain total reflection. The size of the input surface 228 and the output surface 230 may be selected such that the output numerical aperture NA matches a device that receives light from the input light pipe 224.

In one embodiment, the output surface 230 may be disposed adjacent the input 226 of the polarizing beam splitter 202. In some embodiments, the shape of the output surface 230 may be planar, convex, concave, donut or spherical. In one embodiment, input light pipe 224 may receive substantially unpolarized light at input surface 228 and may transmit unpolarized light at output surface 230 to polarizing beam splitter 202. have.

In one embodiment, the input light pipe 224 may be hollow. The output surface 230 may be a lens in which only one side is convex. The convex surface of the output surface 230 may be spherical or cylindrical depending on the final placement and cost of the device. The power of output surface 230 may be designed such that light from output surface 230 is imaged on polarizing beam splitter 202. The inner surface of the input light pipe 224 may be covered with a polarizing retaining material.

In one embodiment, the output light pipe 232 may be disposed adjacent to the output 234 of the supercube 268. In one embodiment, output light pipe 232 may have an input surface 236 disposed adjacent output direction 206 and output surface 238. Output light pipe 232 may receive useful polarizing light 208 and useful polarizing light 204 at input surface 236 and not useful polarizing light 208 at output surface 238. And useful polarizing light 204.

In some embodiments, the shape of the input surface 236 may be planar, convex, concave, donut or spherical. In some embodiments, the shape of the output surface 238 can be planar, convex, concave, donut or spherical. In some embodiments, output light pipe 232 may be made of a material selected from the group consisting of quartz, glass, plastic, or acrylic. In some embodiments, the output light pipe 232 may be a tapered light pipe (TLP) or a straight light pipe (SLP). The surface of the output light pipe 232 may be coated to maintain total reflection polarization. The size of the input surface 236 and the output surface 238 may be selected such that the output numerical aperture NA matches a device that receives light from the output light pipe 232.

In one embodiment, the output light pipe 232 may be hollow. Output surface 238 may be convex in shape. The convex surface of the output surface 238 can be spherical or cylindrical, depending on the final shape and the cost of the device. The power of the output surface 238 can be designed such that light from the output surface 238 is imaged on the image projection system. The inner surface of output light pipe 232 may be coated with a polarizing retaining material.

In one embodiment, shell reflector 240 may reflect light from source 212 to polarizing beam splitter 202. In one embodiment, shell reflector 240 may have a coating that transmits a predetermined portion of the electromagnetic radiation spectrum. This is used to remove invisible invisible light before it is combined in the imager. In some embodiments, the predetermined portion of the electromagnetic radiation spectrum may be infrared, visible light, a predetermined band of wavelengths of light, a specific color of light, or a combination thereof. In other embodiments, the coating may reflect infrared light, visible light, a predetermined band of wavelengths of light, a specific color of light, or any combination thereof.

In one embodiment, shell reflector 240 may have first and second focal points 242 and 244. In one embodiment, the source of electromagnetic radiation 212 is reflected from the shell reflector 240 and emits a beam of light that is substantially converging at the second focal point 244. 242 may be disposed substantially adjacent. In one embodiment, the input surface 228 may be disposed adjacent to the second focal point 244 to collect and transmit substantially all light. In some embodiments, shell reflector 240 may be at least a portion of an elliptical surface of the revolution, a substantially spherical surface of the revolution, or a substantially donut shaped surface of the revolution.

In one embodiment, shell reflector 240 may have a primary reflector 250 having a first optical axis 252, and first focus 242 may be a focal point of primary reflector 250. . In this embodiment, the shell reflector 240 also includes a second optical axis disposed substantially symmetrically to the primary reflector 250 such that the first and second optical axes 252 and 256 are substantially collinear. May be provided with a secondary reflector 254 having 256. In such an embodiment, the second focal point 244 can be the focal point of the secondary reflector 254 and a ray of light can be reflected from the primary reflector 250 toward the secondary reflector 254 and substantially the second focal point. May be collected at 244. In some embodiments, the primary and secondary reflectors 250 and 254 may each be substantially elliptical surfaces of revolution, or substantially parabolic surfaces of revolution.

In one embodiment, the primary reflector 250 may be a substantially elliptical surface of at least a portion of the revolution, and the secondary reflector 254 may be a substantially hyperbolic surface of at least a portion of the revolution. In other embodiments, the primary reflector 250 may be a substantially hyperbolic surface of at least a portion of the revolution, and the secondary reflector 254 may be a substantially elliptical surface of at least a portion of the revolution.

The source 212 may be disposed at the first focal point 242 of the primary reflector 250 to collimate the collected light and direct it to the secondary reflector 254. The output at the input surface 228 can be directed to the input light pipe 224. In such an embodiment, the input light pipe 224 may be a tapered light pipe (TLP). The input light pipe 24 is useful for modifying the numerical aperture or cross sectional area of the image of the source 212. Light may be directed to the supercube polarization recovery system to obtain linearly polarized light in the output light pipe 232. Linear polarized light is also suitable for illumination of LCD-based imager chips that require polarized light.

The degree of collimation may depend on the size of the source 212. Secondary reflector 254 may be disposed symmetrically with respect to primary reflector 250 to occupy a common optical axis. The beam introduced into the secondary reflector 250 is focused at the second focal point 244 where the target, eg, the input light pipe 224, is placed. The input light pipe 224 combines the light from the second focal point 244 of the secondary reflector 254. In one embodiment, the source 212 may be imaged on the target in a ratio of 1: 1 so that the brightness of the source 212 is essentially maintained. The image of the source 212 at the input surface 228 will be exactly the same as the source 212 at a unit magnification, due to the 1: 1 symmetry of the device.

The polarization recovery apparatus 200 can maintain its width through its source collector component. The overall angle of light at the input surface 228 may be approximately 180 degrees around the axis of the source 212 due to the size of the reflectors and approximately 90 degrees around the axis perpendicular to the axis of the source 212. These angles can be very large in applications such as micro displays. In one embodiment, the input light pipe 224 transforms the high input numerical aperture NA and the small input area into a low numerical aperture NA and a larger output area without loss of brightness, thereby reducing the angle. It may be a tapered light pipe (TLP).

In one embodiment, the source 212 may not be circular. In some embodiments, the input of the input light pipe 224 may be designed in a rectangular, elliptical, octagonal, or other cross-sectional shape to match the image shape of the source 212. Inputs conforming to the image of the source 212 may prevent or reduce the reduction in system width due to inconsistency in shape. The output size and aspect ratio of the input light pipe 224 can be designed to match the size and aspect ratio of the imager panel, but the super cube-based configuration can be relatively arbitrary.

The primary and secondary reflectors 250 and 254 may cover a rotation arc range of substantially 180 ° to maximize the collection efficiency, ie, the primary reflector 250 is approximately at the exit of the light source 212. Collect the class almost accurately. Retro-reflector 258 may be disposed on opposite sides of primary reflector 250 to collect the other half of the radiated light. In one embodiment, retro-reflector 258 may be a hemispherical retro-reflector. In one embodiment, the central portion of the bend of the retro-reflector 258 may be disposed adjacent to the source 212 of the lamp. In this embodiment, almost all light can be reflected back through source 212 d to be collected by primary reflector 250 and subsequently focused into a light pipe. In practice, the efficiency of the retro-reflector 258 will be reduced by 60% to 80% by reflection loss, Fresnel reflection loss and distortion loss from the lid of the source 212.

In one embodiment, retro-reflector 258 may be disposed on the side of source 212 symmetrically to shell reflector 240. In one embodiment, retro-reflector 258 may be a spherical retro-reflector. In one embodiment, retro-reflector 258 may be integral with shell reflector 240. In one embodiment, retro-reflector 258 may be a coating that conveys a predetermined portion of the electromagnetic radiation spectrum. This can be used to remove non-visible light that is not useful before it is combined in the imager. In some embodiments, the predetermined portion of the electromagnetic radiation spectrum may be infrared, visible light, a predetermined band of wavelengths of light, a specific color of light, or a combination thereof. In other embodiments, the coating may reflect infrared light, visible light, a predetermined band of wavelengths of light, a specific color of light, or any combination thereof.

In one embodiment of the present invention, image projection device 260 may be disposed adjacent output direction 206 to collect substantially all of the useful polarizable light 204. In some embodiments, image projection device 260 may be a liquid crystal on silicon (LCOS) imager, a digital micrometer device (DMD) chip, or a transmissive liquid crystal display (LCD) panel.

In one embodiment of the invention, the focusing lens 22 may be disposed adjacent the output direction 206, and the image projection device 260 is disposed adjacent the output side 264 of the focusing lens 262. . The image 266 illuminated by the useful polarized light collected and focused by the focusing lens 262 may be emitted by the projection device 260 to be displayed.

In one embodiment of the invention, the method of recovering polarization comprises polarizing light into useful polarized light 204 and unused polarized light 208, and polarized light useful in output direction 206. Conducting 204, reflecting the unused polarized light 208 in a first orthogonal direction orthogonal to the output direction 206, the output direction 206 and the first orthogonal direction Reflecting the non-use polarized light 208 in a second orthogonal direction 216 orthogonal to direction 210 and reflecting the non-use polarized light 208 in the output direction 206. It may include the step of.

Although the invention has been described above, the invention is not limited to the specific embodiments described. It will be apparent to one skilled in the art that many modifications and variations can be made from the specific embodiments described herein within the spirit of the invention.

Claims (39)

A polarizing beam splitter that conducts useful polarizable light 204 in the output direction 206 and reflects the unpolarized light 208 in the first orthogonal direction 210 that is orthogonal to the output direction 206 ( 202); The unpolarized light 208 in the second orthogonal direction 216 disposed reflectively in the first orthogonal direction 210 and orthogonal to the output direction 206 and the first orthogonal direction 210. An initial reflector 214 reflecting); And A final reflector 218 disposed reflectively in the second orthogonal direction 216 to reflect the unusable polarized light 208 in the output direction 206, And wherein said unusable polarizing light (208) is rotated towards said useful polarizing light (204) by said initial and final reflectors (214, 218). The method of claim 1, A first output reflector (220) disposed reflexibly in the output direction (206) to reflect the useful polarizing light (204) in the second orthogonal direction (216); And And a second output reflector 222 disposed reflectively in the second orthogonal direction 216 to reflect the useful polarizable light 204 in the output direction 206. Recovery device 200. The method of claim 2, And the first output reflector (220) is selected from the group consisting of prisms, rectangular prisms, mismatched impedances, and mirrors. The method of claim 2, The first output reflector 220 has a coating that transmits a predetermined portion of the electromagnetic radiation spectrum selected from the group consisting of infrared light, visible light, a predetermined band of wavelengths of light, a specific color of light, and combinations thereof. Polarizing recovery apparatus 200 to be used. The method of claim 2, And the second output reflector (222) is selected from the group consisting of prisms, rectangular prisms, mismatched impedances, and mirrors. The method of claim 2, The second output reflector 222 has a coating that transmits a predetermined portion of the electromagnetic radiation spectrum selected from the group consisting of infrared light, visible light, a predetermined band of wavelengths of light, a specific color of light, and combinations thereof. Polarizing recovery apparatus 200 to be used. The method of claim 1, And further comprising an input light pipe 224 having an input surface 228 and an output surface 230, the output surface 230 disposed adjacent to the input surface 226 of the polarizing beam splitter 202 and And the input light pipe 224 receives unpolarized light at the input surface 228 and reflects the unpolarized light at the output surface 230 to the polarizing beam splitter 202. Polarizing recovery device 200. The method of claim 7, wherein The shape of the input surface (228) is selected from the group consisting of planar, convex, concave, donut, and spherical. The method of claim 7, wherein The shape of the output surface (230) is polarizing recovery device, characterized in that selected from the group consisting of planar, convex, concave, donut, and spherical. The method of claim 7, wherein And the input light pipe (224) is made of a material selected from the group consisting of quartz, glass, plastic, or acrylic. The method of claim 7, wherein And the input light pipe (224) is selected from the group consisting of straight light pipes (SLP) and tapered light pipes (TLP). The method of claim 1, And further comprising an output light pipe 232 having an input surface 234 and an output surface 236 disposed adjacent to the output direction 206, wherein the output light pipe 232 comprises the input surface 234. And receive useful polarizing light (204) and conduct the useful polarizing light (204) at the output surface (236). The method of claim 12, The shape of the input surface 234 is selected from the group consisting of planar, convex, concave, donut, and spherical. The method of claim 12, The shape of the output surface (236) is selected from the group consisting of planar, convex, concave, donut, and spherical. The method of claim 12, And the output light pipe (232) is made of a material selected from the group consisting of quartz, glass, plastic, or acrylic. The method of claim 12, And the output light pipe (232) is selected from the group consisting of straight light pipes (SLP) and tapered light pipes (TLP). The method of claim 1, The original reflector (214) is selected from the group consisting of a prism, a rectangular prism, a mismatched impedance, and a mirror. The method of claim 1, The original reflector 214 has a coating which transmits a predetermined portion of the electromagnetic radiation spectrum selected from the group consisting of infrared light, visible light, a predetermined band of wavelengths of light, a specific color of light, and combinations thereof. Polarization recovery apparatus 200. The method of claim 1, And the final reflector (218) is selected from the group consisting of prisms, rectangular prisms, mismatched impedances, and mirrors. The method of claim 1, The final reflector 218 is provided with a coating for transmitting a predetermined portion of the electromagnetic radiation spectrum selected from the group consisting of infrared light, visible light, a predetermined band of wavelengths of light, a specific color of light, and combinations thereof. Polarization recovery apparatus 200. The method of claim 1, A shell reflector 240 having first and second focal points 242, 244; And A magnetic radiation source 212 disposed adjacent the first focal point 242 of the shell reflector 240 and reflecting from the shell reflector 240 to emit light rays that collect at the second focal point 244. More, And the input surface (228) is disposed adjacent to the second focal point (244) to collect and conduct all the light. The method of claim 21, The shell reflector (240) comprises at least a portion of a shape selected from the group consisting of an elliptical surface of a revolution, a spherical surface of a revolution, and a toroidal surface of a revolution. The method of claim 1, The shell reflector 240 includes a primary reflector 250 having a first optical axis 252, the first focal point 242 is the focal point of the primary reflector 250, The shell reflector 240 further includes a secondary reflector 254 having a second optical axis 256 disposed to be symmetrical to the primary reflector 250, wherein the first and second optical axes 252, 256 is substantially collinear and the second focal point 244 is the focal point of the secondary reflector 254, And the light beam is reflected from the primary reflector (250) towards the secondary reflector (254) and collected at the second focal point (244). The method of claim 23, wherein And the primary and secondary reflectors (250, 254) each comprise at least a portion of a shape selected from the group consisting of an elliptical surface of a revolution and a parabolic surface of a revolution. The method of claim 23, wherein The primary reflector 250 comprises at least a portion of an elliptical surface of a revolution, And the secondary reflector (254) comprises at least a portion of a hyperbolic surface of a revolution. The method of claim 23, wherein The primary reflector 250 comprises at least a portion of a hyperbolic surface of a revolution, And the secondary reflector (254) comprises at least a portion of an elliptical surface of a revolution. The method of claim 23, wherein The shell reflector 240 is provided with a coating for transmitting a predetermined portion of the electromagnetic radiation spectrum selected from the group consisting of infrared, visible light, a predetermined band of wavelengths of light, a specific color of light, and combinations thereof. Polarization recovery apparatus 200. The method of claim 21, And a retroreflector (258) disposed on a side of the source opposite the shell reflector (240). The method of claim 28, The retroreflector (258) is a spherical retroreflector (258). The method of claim 28, The retroreflector 258 is characterized by having a coating for transmitting a predetermined portion of the electromagnetic radiation spectrum selected from the group consisting of infrared, visible light, a predetermined band of wavelengths of light, a specific color of light, and combinations thereof. Polarization recovery apparatus 200. The method of claim 21, And the source of electromagnetic radiation (212) comprises an arc lamp. The method of claim 31, wherein The arc lamp is characterized in that it comprises a lamp selected from the group consisting of xenon lamps, metal halide lamps, UHP lamps, HID lamps or mercury lamps. Photonic Recovery Device 200. The method of claim 21, The source (212) of electromagnetic radiation is selected from the group consisting of halogen lamps and filament lamps. The method of claim 1, And an image projection device (260) disposed adjacent said output direction (206) to collect said useful polarizing light (204). The method of claim 34, wherein The image projection apparatus 260 is selected from the group consisting of a silicon liquid crystal (LCOS) imager, a digital micrometer device (DMD) chip, and a transmissive liquid crystal display (LCD) panel. (200). The method of claim 21, And the shape of the polarizing beam splitter (202) coincides with the opening of the source of electromagnetic radiation (212). The method of claim 1, And wherein said polarizing beam splitter (202) comprises a wire-grid polarizing beam splitter. Polarizing the light into useful polarizable light 204 and unused polarizable light 208; Conducting said useful polarizing light 204 in an output direction 206; Reflecting the unusable polarized light (208) in a first orthogonal direction orthogonal to the output direction (206); Reflecting the unusable polarized light (208) in the second orthogonal direction (216) orthogonal to the output direction (206) and the first orthogonal direction (210); And Reflecting the unusable polarized light (208) in the output direction (206). Means for polarizing the light into useful polarizable light 204 and unused polarized light 208; Means for conducting said useful polarizing light 204 in an output direction 206; Means for reflecting the unusable polarized light (208) in a first orthogonal direction orthogonal to the output direction (206); Means for reflecting the unusable polarized light (208) in the second orthogonal direction (216) orthogonal to the output direction (206) and the first orthogonal direction (210); And And means for reflecting the unusable polarized light (208) in the output direction (206).