Abstract: Disclosed is an optical component, which comprises a prism element adjacent to a lens element, where the two elements are separated by a small air gap. In disclosed embodiments, the elements have adjacent and parallel surfaces which are substantially planar and which, with the small air gap, operate through Total Internal Reflection (“TIR”) to direct light beams that strike the planar surfaces. Light beams that strike at less than the critical angle are internally reflected, while light beams which strike at greater than the critical angle pass through. The TIR surfaces thereby separate the desired optical signals from the spurious ones. The combined TIR prism lens operates as a single and integrated component which directs desired light beams to a reflective optical processing element such as a Spatial Light Modulator and which focuses the processed light beams as they leave the combined TIR prism lens.

Abstract: Prism elements having TIR surfaces placed in close proximity to the active area of a SLM device 302 to separate unwanted off-state 324 and/or flat-state 326 light from the projection ON-light bundle 322. The TIR critical angle of these prisms is selected to affect either the off-state light or additionally, any portion of flat-state light reflected from the SLM. These TIR surfaces are placed to immediately reflect the unwanted light as it comes off the SLM, thereby preventing the contamination of light along the projection path, which tends to degrade the system contrast. To further improve the optical performance of the system, these TIR prisms can be attached directly to the SLM package 300, completely eliminating the package window.

Abstract: A TIR prism for use in projection displays, which enables angular separation of input illumination and projection light. By controlling the critical angle of a TIR surface, a portion of the illumination cone can be made to fail TIR, thereby being removed from the system prior to overlapping the projected light and lowering the image contrast. Since this truncation of the illumination aperture is translated proportionally across all optical apertures, the input aperture can be increased to overcome the loss of image brightness due to removing this portion of the illumination. In addition, other TIR surfaces are incorporated to remove unwanted diffracted light from OFF-pixels and flat-surfaces soon after this light enters the prism, preventing it from scattering into the desired projected light path from the ON-state pixels.

Abstract: The present application describes embodiments of a neutral density color wheel filter. According to one embodiment, a neutral density color wheel (100) includes an opaque coating (135) over one or more color segments (120, 130, 140, 150, 160, 170) with randomly placed transmissive regions (131). The transmissive regions (131) can be configured to substantially transmit incident light and the opaque coating (135) can be configured to substantially block or absorb the incident light. Alternatively, the transmissive regions (131) can be configured to substantially transmit the incident light. The color segments with opaque coating (135) and transmissive regions (131) substantially eliminate light recycling due to the reflection from the color wheel. The light transmission from the color wheel (100) is independent of the optics of a display system.

Abstract: The addition of DMD illumination modulator(s) 702 in series with projection SLM(s) 706/709 to produce high-performance projection displays with improved optical efficiency, reliability, and lower maintenance requirements. This approach eliminates the vibration, audible noise, and safety problems associated with high speed rotating color filter wheels 203 commonly used in SLM projectors and controls the light applied to individual areas of the projection SLM(s).

Abstract: An image display system includes a light source capable of generating an illumination light beam along an illumination path. The system also includes a modulator operable to receive at least a portion of the illumination light beam and to selectively communicate at least some of the illumination light beam received by the modulator along a projection light path. The system further includes at least one adjustable illumination aperture operable to selectively control an amount of the at least a portion of the illumination light beam received by the modulator based at least in part on image data.

Abstract: A three element prism system and method for splitting/combining three different colors of light arranged such that the size of a selected one of the color prism, such as for example, the red prism and, consequently the clear aperture, are increased without a corresponding increase in the size of the other prisms (e.g., the blue and green prisms). This is accomplished by adjusting the air gap A2 of the selected light path (e.g., red) so that the effective total selected light path T, which includes the selected light air gap A2 and the selected light glass path G2 is the same as the total path length T of both the other light paths (e.g., green and blue) comprised of air gap A1 plus glass path G1.

Abstract: A projection lens that uses a TIR surface as both an angular filter and fold mirror. A first lens element 602 is placed very close to the TIR prism assembly 604. Because the lens is so close, it gathers both off state and state light from the modulator. Off state light from the DMD follows path 606 while on state light follows path 608. A total internal reflection surface 610 receives both the on state and the off state light. Because the off state light strikes the TIR surface at an angle less than the Brewster's angle, the off state light passes through the TIR prism and is removed from the projection path. The on state light strikes the TIR surface at an angle greater than Brewster's angle and is reflected by the TIR surface through the remaining projection lens components.

Abstract: A sequential color display system using a white light source (202) to create a full color image projected onto an image plane (214). A dynamic filter (206), typically a series of moving dichroic filters, generates a series of primary colored light beams that are swept across the surface of a spatial light modulator (210). Light rejected by the dynamic filter (206) enters a light recycler (204) and is reapplied to the dynamic filter (206). The light recycler is typically one or more reflective surfaces, including mirrors, baffles, enclosures, lamp reflectors, TIR surfaces, or specially coated material arranged in such a way as to encourage light toward an aperture separating the light recycler (204) and the dynamic filter (206). Typically all three primary colors are produced simultaneously by the dynamic filter (206).

Abstract: An image display system includes a light source capable of generating an illumination light beam along an illumination path. The system also includes a modulator operable to receive at least a portion of the illumination light beam and to selectively communicate at least some of the illumination light beam received by the modulator along a projection light path. The system further includes at least one adjustable illumination aperture operable to selectively control an amount of the at least a portion of the illumination light beam received by the modulator based at least in part on image data.

Abstract: A method and system for improving the contrast ratio of a projected image. An asymmetric aperture stop within a lens is used to provide a 20-30% improvement in the contrast ratio of a projected image when used with offset projection. Using slightly offset projection, the majority of the on-state projection light from the modulator array passes through a region (512) that is not centered in the projection lens pupil. The blocked region (504) of the asymmetric aperture is oriented toward the illumination path (510) and away from the specular reflection path (508). The asymmetric aperture (502) is able to block a significant portion of the diffracted light using the blocked region (504), without blocking much of the desired projection light passing through the remainder of the aperture. The result is that dark regions of the image become significantly darker, while light regions remain about the same. The same effect occurs without the offset illumination shown in FIG. 3, but to a lesser extent.

Abstract: A method and system for improving the contrast ratio of a projected image. An asymmetric aperture stop within a lens is used to provide a 20-30% improvement in the contrast ratio of a projected image when used with offset projection. Using slightly offset projection, the majority of the on-state projection light from the modulator array passes through a region (512) that is not centered in the projection lens pupil. The blocked region (504) of the asymmetric aperture is oriented toward the illumination path (510) and away from the specular reflection path (508). The asymmetric aperture (502) is able to block a significant portion of the diffracted light using the blocked region (504), without blocking much of the desired projection light passing through the remainder of the aperture. The result is that dark regions of the image become significantly darker, while light regions remain about the same. The same effect occurs without the offset illumination shown in FIG. 3, but to a lesser extent.

Abstract: Prism elements having TIR surfaces placed in close proximity to the active area of a SLM device 302 to separate unwanted off-state 324 and/or flat-state 326 light from the projection ON-light bundle 322. The TIR critical angle of these prisms is selected to affect either the off-state light or additionally, any portion of flat-state light reflected from the SLM. These TIR surfaces are placed to immediately reflect the unwanted light as it comes off the SLM, thereby preventing the contamination of light along the projection path, which tends to degrade the system contrast. To further improve the optical performance of the system, these TIR prisms can be attached directly to the SLM package 300, completely eliminating the package window.

Abstract: Prism elements having TIR surfaces placed in close proximity to the active area of a SLM device 302 to separate unwanted off-state 324 and/or flat-state 326 light from the projection ON-light bundle 322. The TIR critical angle of these prisms is selected to affect either the off-state light or additionally, any portion of flat-state light reflected from the SLM. These TIR surfaces are placed to immediately reflect the unwanted light as it comes off the SLM, thereby preventing the contamination of light along the projection path, which tends to degrade the system contrast. To further improve the optical performance of the system, these TIR prisms can be attached directly to the SLM package 300, completely eliminating the package window.

Abstract: An optical system and method of increasing the contrast of a projected image. The optical system 1800 comprises a combination of aperture stops 1810, 1812 in at least one of the illumination and projection paths to filter scattered light and/or light prone to scatter into the projection aperture.

Abstract: A TIR prism for use in projection displays, which enables angular separation of input illumination and projection light. By controlling the critical angle of a TIR surface, a portion of the illumination cone can be made to fail TIR, thereby being removed from the system prior to overlapping the projected light and lowering the image contrast. Since this truncation of the illumination aperture is translated proportionally across all optical apertures, the input aperture can be increased to overcome the loss of image brightness due to removing this portion of the illumination. In addition, other TIR surfaces are incorporated to remove unwanted diffracted light from OFF-pixels and flat-surfaces soon after this light enters the prism, preventing it from scattering into the desired projected light path from the ON-state pixels.

Abstract: A projection lens that uses a TIR surface as both an angular filter and fold mirror. A first lens element 602 is placed very close to the TIR prism assembly 604. Because the lens is so close, it gathers both off state and state light from the modulator. Off state light from the DMD follows path 606 while on state light follows path 608. A total internal reflection surface 610 receives both the on state and the off state light. Because the off state light strikes the TIR surface at an angle less than the Brewster's angle, the off state light passes through the TIR prism and is removed from the projection path. The on state light strikes the TIR surface at an angle greater than Brewster's angle and is reflected by the TIR surface through the remaining projection lens components.

Abstract: Disclosed is an optical component, which comprises a prism element adjacent to a lens element, where the two elements are separated by a small air gap. In disclosed embodiments, the elements have adjacent and parallel surfaces which are substantially planar and which, with the small air gap, operate through Total Internal Reflection (“TIR”) to direct light beams that strike the planar surfaces. Light beams that strike at less than the critical angle are internally reflected, while light beams which strike at greater than the critical angle pass through. The TIR surfaces thereby separate the desired optical signals from the spurious ones. The combined TIR prism lens operates as a single and integrated component which directs desired light beams to a reflective optical processing element such as a Spatial Light Modulator and which focuses the processed light beams as they leave the combined TIR prism lens.

Abstract: The addition of DMD illumination modulator(s) 702 in series with projection SLM(s) 706/709 to produce high-performance projection displays with improved optical efficiency, reliability, and lower maintenance requirements. This approach eliminates the vibration, audible noise, and safety problems associated with high speed rotating color filter wheels 203 commonly used in SLM projectors and controls the light applied to individual areas of the projection SLM(s).

Abstract: A micromirror device having an array of mirrors 802 formed with a jagged leading 804 and trailing 806 edge. The jagged leading and trailing edges eliminate the features that cause the most diffraction-straight edges that are perpendicular to the incident illumination 808. The leading and trailing edges preferably are formed as a series of saw teeth having a 45° angle to the incident illumination 808. Angling the edges relative to the illumination axis greatly reduces the diffraction that would occur from edges perpendicular to the illumination axis. By reducing the diffraction, the jagged leading and trailing edges enable the use of orthogonal illumination which reduces the cost, size, and weight of the associated TIR prism. The number of saw teeth can vary, but the three-tooth pattern provides an optimum mixture of low diffraction and ease of production.