Projection system with rotatable anamorphic lens

Abstract

To provide a projection system having a rotatable anamorphic lens.SOLUTION: The light projection system includes a light source, a light integrator, a relay lens system including two or more rotatable anamorphic lenses, the anamorphic lenses being tilted about an optical axis to transform a uniform pattern of light into an image having a specified aspect ratio, at least one spatial light modulator configured to receive the image and direct a spatially modulated image into an optical path, and at least one projection lens configured to receive the spatially modulated image from the optical path and project the spatially modulated image onto an image plane with the specified aspect ratio. In a DLP projection system, the relative angle of two or more rotatable anamorphic lenses is less than 90 degrees in order to pre-distort the image and result in a more rectangular spatially modulated image with a specified aspect ratio.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to the following priority applications: U.S. Provisional Application No. 63 / 034,311 (Reference No. D19051USP1), filed June 3, 2020; and European Application No. 20178043.4 (Reference No. D19051EP), filed June 3, 2020.

[0002] [Technical field] FIELD OF THE DISCLOSURE The present disclosure relates generally to improvements in optical projection systems. [Background technology]

[0003] Digital Light Processing (DLP) projection systems are used worldwide for digital cinema. The Digital Cinema Initiatives (DCI) was formed in March 2002 as a joint project of major film studios to develop system specifications for digital cinema. DCI-compliant DLP cinema projectors use two formats related to the way films are shot and edited. These two formats include "flat" (also known as "Academy"), which has an aspect ratio of 1.85:1, and "Cinemascope" (also known as "Scope"), which is 2.66:1 wide but is usually projected at 2.35:1.

[0004] In a DLP projection system, the image is generated by a spatial light modulator (SLM), such as a matrix of tiny mirrors arranged on a semiconductor chip known as a digital micro-mirror device (DMD). The DMD is an electromechanical device whose pixel-generating elements form an array of hundreds or thousands of tiny tiling mirrors. To allow the mirrors to tilt, each is attached to one or more hinges mounted on support posts and spaced apart by an air gap above underlying control circuitry. The control circuitry provides electrostatic forces that selectively tilt the corner mirrors. Light incident on the mirror array is reflected in one direction by the "on" mirrors and in another direction by the "off" mirrors. The pattern of "on" versus "off" mirrors forms the image.

[0005] In most applications, light waves from the DMD are projected onto a screen by a projection lens. In projection systems with a single DLP chip, color is generated by placing a color wheel between a white lamp and the DLP chip, or by using individual light sources to generate the primary colors. In DLP projection systems with a DLP chip, a prism is used to separate the light from the lamp, and each primary color of light is routed to its own DMD chip. In the DMD chip, each primary color is recombined with the other primary colors and routed through a lens.

[0006] In a liquid-crystal display (LCD) projection system, a light source emits a beam of intense white light that passes through a light integrator (e.g., a fly's eye integrator), which homogenizes the light. The homogenized light is then passed to a dichroic mirror coated with a film designed to reflect only certain wavelengths of color, creating red, green, and blue light beams. Some LCD projectors use individual LEDs for each color rather than a film-coated dichroic mirror. The red, green, and blue light beams pass through a transmissive LCD panel made up of tiny pixels that block or pass light when triggered by an electric current. The red, green, and blue tints output by the LCD panel are recombined in a dichroic prism into a single image composed of millions of colors. The single image is then projected onto a screen by a projection lens. Summary of the Invention

[0007] The present disclosure relates to a projection system with a rotatable anamorphic lens.

[0008] According to an aspect of the present disclosure, there is provided a digital light processing (DLP) projection system. The DLP projection system comprises: A light source and a rectangular integrator rod configured to receive light from the light source and distribute the light in a uniform pattern; a relay lens system including two or more rotatable anamorphic lenses, the anamorphic lenses being tilted about an optical axis to simultaneously convert the uniform pattern of light into an image having a specified aspect ratio, the relative angles of the anamorphic lenses to each other being less than 90 degrees to pre-distort the image; at least one spatial light modulator configured to receive the pre-distorted image and direct a spatially modulated image onto a light path; at least one projection lens configured to receive the spatially modulated image from the optical path and project the spatially modulated image onto an image plane with the specified aspect ratio; Includes.

[0009] According to another aspect, a liquid crystal display (LCD) projection system is provided. The LCD projection system comprises: A light source and a lens array configured to receive light from the light source and distribute the light in a uniform pattern; a relay lens system including two or more rotatable anamorphic lenses, the anamorphic lenses tilted about an optical axis to convert the uniform pattern of light into an image having a specified aspect ratio, the anamorphic lenses having a compression ratio of approximately 1.13:1; at least one spatial light modulator configured to receive the image and direct a spatially modulated image onto a light path; at least one projection lens configured to receive the spatially modulated image from the optical path and project the spatially modulated image onto an image plane with the specified aspect ratio; Includes.

[0010] The details of the disclosed implementations are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will become apparent from the description, drawings, and claims.

[0011] Certain embodiments disclosed herein provide one or more of the following advantages: The illumination aspect ratio of the projection system is changed (e.g., from an aspect ratio of 2.35 to 1.85) using two or more rotatable anamorphic lenses. Changing the aspect ratio allows only pixels representing data to be illuminated on the image plane, thereby increasing the brightness of the projected image. Additionally, DLP projection systems use rotatable anamorphic lenses to pre-distort the image projected onto the DMD chip, producing a more rectangular spatially modulated image.

[0012] In the accompanying drawings referenced below, various embodiments are illustrated as block diagrams, flowcharts, and other figures. Each block in a flowchart or block may represent a module, program, or portion of code, including one or more executable instructions for performing specified logical functions. Although these blocks are shown in a particular order for performing method steps, they do not necessarily have to be performed in the exact order shown. For example, they may be performed in reverse order or simultaneously, depending on the characteristics of each operation. It should be noted that each block in the block diagrams and / or flowcharts, and combinations thereof, may be implemented by a dedicated software-based or hardware-based system that performs the specified functions / operations, or by a combination of dedicated hardware and computer instructions. [Brief explanation of the drawings]

[0013] [Figure 1A] FIG. 1 is a side view of an exemplary illumination system of an optical projection system.

[0014] [Figure 1B] A typical illumination area showing a parallelogram image of a rectangular integrator rod projected onto the SLM surface is shown.

[0015] [Figure 2] FIG. 1 is a conceptual diagram illustrating a relay lens system using paraxial lenses, showing the orientation of cylindrical optics (rectangular) to stretch an image vertically, according to an embodiment.

[0016] [Figure 3] 3 is a conceptual diagram of the relay lens system of FIG. 2 showing the orientation of the cylindrical optics (rectangle) that stretches the image laterally, according to an embodiment.

[0017] [Figure 4] 10 illustrates a rectangular illumination spot with the cylindrical lens rotated to a first position to reduce distortion, according to an embodiment.

[0018] [Figure 5] 10 illustrates a rectangular illumination spot with the cylindrical lens rotated to a second position to reduce distortion, according to an embodiment.

[0019] [Figure 6] FIG. 1 is a conceptual block diagram of a DLP projection system using a relay lens system with a rotatable anamorphic lens, according to an embodiment.

[0020] [Figure 7] FIG. 1 is a conceptual block diagram of an LCD projection system using a relay lens system with a rotatable anamorphic lens, according to an embodiment.

[0021] The same reference numbers used in the various drawings indicate similar elements. DETAILED DESCRIPTION OF THE INVENTION

[0022] Cinema microdisplays have an aspect ratio of 2048x1080 (or 4096x2160), which does not match the geometry of either DCI format, so some pixels are unused. In the case of a scope, several dozen rows of pixels at the top and bottom of the microdisplay do not display data but remain illuminated by the optics, which are currently optimized to illuminate the entire chip in both formats. In flat projection systems, some rows of pixels are unused but would be illuminated anyway.

[0023] Typical projection systems use one of two methods to homogenize the light and create uniform illumination. The first method uses a rectangular integrator rod (solid or hollow). The second method uses a lens array, as found in most LCD projectors. In the first method, the image of the rectangular integrator rod is projected onto the image plane. In DLP projection systems, the DMD surface is illuminated at a 24-degree angle (from the vertical or y-axis, where the z-axis is the optical axis) and a 45-degree clocking angle (from the horizontal or x-axis), resulting in some distortion of the image of the rectangular integrator rod. If the imaging optics are telecentric, the projected image will be a parallelogram rather than a rectangle.

[0024] In DLP and LCD projection systems, an anamorphic telescope is placed in the projection system's illumination relay optics. The anamorphic telescope "compresses" the image on the rectangular integrator rod by a specified amount. Anamorphic optics enlarge the image in one axis but do not change the image size along the orthogonal axis. By using an optical integrator with a specified aspect ratio and compression (e.g., a 2.08:1 aspect ratio and a 1.13:1 compression), an image on the SLM surface is created with the desired DCI-compliant aspect ratio (e.g., an aspect ratio of 2.35:1 or 1.85:1), depending on the orientation of the anamorphic optics (e.g., 2.08 x 1.13 = 2.35 and 2.08 / 1.13 = 1.85).

[0025] In a DLP projection system, arranging cylindrical anamorphic lenses in a relay lens system at a suitable angle (e.g., less than 90 degrees) relative to each other pre-distorts the image, making the illumination spot on the DMD surface more rectangular. Therefore, in addition to solving the dual-format cinema projection problem, rotatable anamorphic lenses can also be used in a specific direction to rectangularize the illumination shape of a DLP projection system. This reduces the magnification required to illuminate the DMD surface and improves efficiency by approximately 8-10%.

[0026] Although the exemplary embodiments disclosed herein are optimized for only one color, more complex optics utilizing various glasses can be used to simultaneously focus all three primary colors (red, green, and blue) onto each SLM.

[0027] Exemplary Embodiments FIG. 1A illustrates an exemplary illumination system 100 for an optical projection system. The illumination system 100 includes an optical integrator 101, a relay lens 102, and an SLM 103. In a DLP projection system embodiment, the optical integrator 101 is a rectangular integrator rod. The rectangular integrator rod is a hollow or solid, internally reflecting "light pipe" that uses multiple reflections of a focused light source to obtain uniformity of round or irregular illumination patterns and convert them into a uniform rectangular pattern. This pattern is imaged by the relay lens system 102 onto the SLM 103 (e.g., a DMD chip), which is then projected onto an image plane (e.g., a theater screen) by a projection lens (not shown). The rectangular integrator rod 101 is used to improve uniformity and efficiently match the aspect ratio of the illumination source and the SLM 103. The relay lens system 102 contains relay optics used to position the uniform rectangular pattern on the SLM 103.

[0028] In DLP projection systems, the SLM 103 is typically illuminated at an angle (from normal) twice the micromirror tilt angle (e.g., 24 degrees for a 12-degree tilt device) and a clocking angle (from horizontal) of 45 degrees, resulting in some distortion of the image on the SLM 103. This distortion is typical of rod-based DLP projection systems and reduces efficiency. The relay lens system 200, described below with reference to Figures 2 and 3, includes two or more rotatable anamorphic lenses to change the aspect ratio of the image projected onto the SLM 103 (e.g., a DMD chip) and eliminate image distortion, resulting in a substantially rectangular image that utilizes all pixels of the aspect ratio. In effect, the anamorphic optical system produces a parallelogram image on a flat surface, but when this image strikes the SLM 103 at 24 degrees, the parallelogram distortion is canceled. The anamorphic ratio (AR) of the cylindrical lens group (the ratio of the focal lengths of the illumination relays parallel and perpendicular to the axis of the cylinder) preferably satisfies the condition AR>1 / cos(θ), where θ is the illumination angle of the SLM103, nominally 24 degrees.

[0029] FIG. 1B shows a typical illumination area showing a parallelogram image of the rectangular integrator rod 101 projected onto the SLM 103.

[0030] Figure 2 shows a relay lens system using paraxial lenses, showing the orientation of the cylindrical optics (rectangle) to stretch the image vertically, according to an embodiment. Figure 3 shows the relay lens system of Figure 2, showing the orientation of the cylindrical optics (rectangle) to stretch the image horizontally, according to an embodiment.

[0031] An exemplary relay lens system 200 shown in Figures 2 and 3 includes rotatable anamorphic lenses 201 and 202 (forming an "anamorphic telescope"), spherical illumination lenses 203 and 204, and an SLM 205. The lines passing through the optical system in Figure 2 represent light rays from a light source (not shown), which can be any coherent light source, such as white light, a high-power light-emitting diode (LED), or a laser.

[0032] In an embodiment, spherical illumination lenses 203, 204 project an image of a rectangular integrator rod (not shown) without affecting its aspect ratio. Meanwhile, anamorphic lenses 201, 202 project a version of the rectangular integrator rod's image compressed along its longer dimension (typically by a factor of two). In the illustrated embodiment, anamorphic lenses 201, 202 are cylindrical lenses with any desired surface type, including, but not limited to, convex, concave, biconcave, or a combination of convex and concave surfaces (a "meniscus" surface type). In an embodiment, dual elements can be used to reduce light loss and increase the contrast ratio of the displayed image.

[0033] The degree to which the anamorphic lenses 201, 202 correct the aspect of the image they receive (referred to herein as the "aspect correction ratio") is determined by many factors, including the radius, thickness, and glass type of each element of the lens. Therefore, the same configuration of anamorphic lenses 201, 202 can be modified to have different optical prescriptions, thereby providing other correction ratios. The anamorphic lenses 201, 202 can be any size sufficient to capture all or most of the light rays from the light source. For example, the anamorphic lens 201 can be the same size as the anamorphic lens 202, or they can be different sizes.

[0034] As previously mentioned, the orientation of anamorphic lenses 201, 202 shown in Figure 2 "stretches" the image vertically, while the orientation of anamorphic lenses 201, 202 shown in Figure 3 "stretches" the image horizontally. Note that the orientation of anamorphic lenses 201, 202 shown in Figure 3 is rotated 90 degrees about the optical axis from the orientation shown in Figure 2. In an embodiment where the aspect ratio of the rectangular integrator rod is 2.08:1 and anamorphic lenses 201, 202 provide 1.13:1 compression, the image projected at image plane 205 will have a DCI-compliant aspect ratio of 2.35:1 or 1.85:1 (since 2.08 x 1.13 = 2.35 and 2.08 / 1.13 = 1.85). Thus, stretching the image projected onto image plane 205 modifies the projection system's illumination intensity to illuminate only the pixels representing the data, increasing the brightness of the projected image by up to 20%. In practice, the rectangular integrator rod 101 does not have the exact aspect ratio of the desired illumination spot in the case of DLP illumination, because the image is stretched by impinging on the DMD face at an oblique angle. In the case of LCD projection, when the illumination is perpendicular to the LCD modulation panel, the integrator aspect ratio more closely matches the desired illumination shape.

[0035] In an embodiment, the anamorphic lenses 201, 202 are mounted in a lens barrel with bearings or other mechanical devices that facilitate rotation of the anamorphic lenses 201, 202 about their optical axes, and an appropriate control system can be used to manually or automatically rotate the lenses 201, 202, as described with reference to FIG. 6 . For example, the anamorphic lenses 201, 202 can be rotated 90 degrees about their optical axes whenever a change in DCI format is required. In an embodiment, the anamorphic lenses 201, 202 are mounted in a lens turret attached to the projector that can be manually or automatically rotated to orient the lenses about their optical axes. As used herein, an "optical axis" is, to a first approximation, an imaginary line that defines the path that light propagates through a projection system. As used herein, an "optical path" is the path that light follows as it travels through an optical medium or optical system.

[0036] In a DLP projection system, the anamorphic lenses 201, 202 can be used to pre-distort the image projected onto the SLM 205, when placed at a particular orientation in the relay lens system 200, so that the image becomes more rectangular.

[0037] Figure 4 shows a rectangular illumination spot with cylindrical anamorphic lenses 201, 202 rotated to a first position, according to an embodiment. Figure 5 shows a rectangular illumination spot with cylindrical anamorphic lenses 201, 202 rotated to a second position, according to an embodiment. The first and second positions can be empirically determined for a particular application and projection system illumination optics using computer-based modeling and simulation.

[0038] Therefore, in addition to solving the dual-format cinema projection problem, the addition of rotatable anamorphic lenses 201, 202, which rotate at a specific relative orientation to each other (e.g., less than 90 degrees), allows DLP projection systems to achieve a more rectangular shape for the illuminated image. A more rectangular image reduces the magnification required to illuminate the DMD chip, improving efficiency by approximately 8-10%.

[0039] Although the exemplary embodiments disclosed herein are optimized for only one color, more complex optics utilizing various glasses can be used to simultaneously focus all three primary colors (red, green, and blue) onto each SLM (e.g., DMD chip, LCD panel).

[0040] 6 is a conceptual block diagram of a DLP projection system 600 using a relay lens system with a rotatable anamorphic lens, according to an embodiment. System 600 is for monochrome only. Those skilled in the art will recognize that a DLP projection system can be adapted for three colors by using a color wheel or a Total Internal Reflection (TIR) ​​prism to split the light to the primary colors and separate DLD chips for each color. The relay lens system can include a separate lens assembly for each color, or three separate relay lens systems can be used to change formats and correct image distortion.

[0041] System 600 includes a light source 601, a light integrator 602, a relay lens system 603, a spatial light modulator 604, a projection lens or lens group 605, a lens controller 607, a processor 608, and a memory 609. The dotted arrows in Figure 6 represent the optical path. Note that Figure 6 is simplified for clarity, and a practical DLP projection system would include other components such as optical reflectors, mirrors (e.g., folding mirrors, dichroic mirrors, front surface mirrors) and / or lenses (e.g., focusing lenses, shaping lenses, collimating lenses, condenser lenses) and / or apertures (e.g., vignetting apertures) for directing and / or focusing the light beams, diffractive beam shapers, light sinks, and color wheels or prism assemblies (e.g., TIR prisms) for processing the light paths of the three primary colors (red, green, and blue).

[0042] In the illustrated exemplary embodiment, light source 601 illuminates light integrator 602. In an embodiment, light integrator 602 is a solid or hollow rectangular integrator rod. Light source 601 can be a high-pressure xenon arc lamp unit, an LED, or a laser. Light integrator 602 outputs a uniform rectangular pattern, which is imaged by relay lens system 603 onto spatial light modulator 604 and then projected by projection lens 605 onto image plane 606 (e.g., a theater screen). In an embodiment, spatial light modulator 604 is a DMD, a liquid crystal display (LCD), or a liquid crystal on silicon (LCoS).

[0043] The relay lens system 604 includes two or more rotatable anamorphic lenses, as described with reference to FIGS. 2 and 3 . In an embodiment, the anamorphic lenses are cylindrical. In an embodiment, the relay lens system 603 includes a barrel for housing the anamorphic lenses and, optionally, other illumination optics. The anamorphic lenses are mounted within a barrel on bearings or other suitable mechanical devices to facilitate rotation of the lenses in two different directions, as described with reference to FIGS. 2 and 3 . In an embodiment, the rotation of the anamorphic lenses is controlled by a lens control 607, which is controlled by a processor 608. In an embodiment, the processor 608 also controls the operation of the spatial light modulator 604 based on software or firmware instructions stored in a memory 609. In other embodiments, a separate processor is used to control the operation of the spatial light modulator 604 from the processor used to control the rotation of the anamorphic lenses of the relay lens system 603.

[0044] During operation, a projectionist can use an input device (e.g., a computer graphical user interface) to change the format and set the angular position of the anamorphic lens to remove distortion. Input provided by the projectionist is processed by a processor 608, which instructs the lens control unit 607 to send control signals to the relay lens system 603 to rotate the anamorphic lens. In an embodiment, the relay lens system 603 includes a rotational actuator coupled to a lens holder for holding the anamorphic lens in the optical path and one or more feedback sensors (e.g., angular velocity sensors) for providing closed-loop feedback to the lens control unit 607. The lens control unit 607 can be a processor or an application-specific integrated circuit (ASIC) that executes software or firmware instructions. The lens control unit 607 can implement a state machine and / or appropriate control algorithms to control the lens rotation in a stable manner. In another embodiment, the anamorphic lens is manually rotated by a user using a hardware mechanism (e.g., a lever) attached to the relay lens system 603.

[0045] FIG. 7 is a conceptual block diagram of an LCD projection system 700 that uses a relay lens system with a rotatable anamorphic lens, according to an embodiment.

[0046] Light source 701 emits a beam of intense white light that passes through a light integrator (e.g., fly's eye integrator 702), which homogenizes the light. The homogenized light is passed to a dichroic mirror, which is coated with a film designed to reflect only certain wavelengths of color, creating red, green, and blue light beams. In some LCD projection systems, the white light and dichroic mirror are replaced with red, blue, and green LEDs. The red, green, and blue light beams pass through a relay lens system 707. The output of relay lens system 707 passes through a transmissive LCD panel 708, which is made up of tiny pixels that block or pass light when triggered by an electric current. The red, green, and blue color images output by the transmissive LCD panel 708 are recombined by a dichroic prism 709 into a single image composed of millions of colors. The single image is projected onto a screen by a projection lens 710.

[0047] The relay lens system 707 includes two or more rotatable anamorphic lenses, as described with reference to FIGS. 2 and 3 . In an embodiment, the anamorphic lenses are cylindrical. In an embodiment, the relay lens system 707 includes a barrel for housing the anamorphic lenses and, optionally, other illumination optics. The anamorphic lenses are mounted within a barrel on bearings or other suitable mechanical devices to facilitate rotation of the lenses in two different directions, as described with reference to FIGS. 2 and 3 . In an embodiment, the rotation of the anamorphic lenses is controlled by a lens control unit 704, which is controlled by a processor 705. In an embodiment, the processor 705 also controls the operation of the transmissive LCD panel 708 based on software or firmware instructions stored in memory 706. In other embodiments, a separate processor is used to control the operation of the transmissive LCD panel 708 from the processor used to control the rotation of the anamorphic lenses of the relay lens system 707.

[0048] During operation, a projectionist can use an input device (e.g., a computer graphical user interface) to change the format and set the angular position of the anamorphic lens to remove distortion. Input provided by the projectionist is processed by a processor 705, which instructs the lens control 704 to send control signals to the relay lens system 707 to rotate the anamorphic lens. In an embodiment, the relay lens system 707 includes a rotational actuator coupled to a lens holder for holding the anamorphic lens in the optical path and one or more feedback sensors (e.g., angular velocity sensors) for providing closed-loop feedback to the lens control 704. The lens control 704 can be a processor or an application-specific integrated circuit (ASIC) that executes software or firmware instructions. The lens control 704 can implement a state machine and / or appropriate control algorithms to control the lens rotation in a stable manner. In another embodiment, the anamorphic lens is manually rotated by a user using a hardware mechanism (e.g., a lever) attached to the relay lens system 707.

[0049] While the present specification includes numerous specific implementation details, these should not be considered limitations on the scope of what may be claimed, but rather as descriptions of features specific to a particular implementation. Certain features described herein in the context of separate embodiments may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single embodiment may also be implemented separately or in any suitable subcombination in multiple embodiments. Furthermore, while features may be described above as operating in a particular combination and initially claimed as such, one or more features from the claimed combination may, in some cases, be separated from the combination, and the claimed combination may be directed to a subcombination or a variation of the subcombination. The logical flow depicted in the figures does not require the particular order or sequential order depicted to achieve desirable results. Furthermore, other steps may be provided or steps may be removed from the described flow, and other components may be added or removed from the described system. Accordingly, other implementations are within the scope of the following claims.

[0050] Various aspects of the invention may be apparent from the following enumerated example embodiments (EEE). (EEE1) An optical projection system, comprising: A light source and a light integrator configured to receive light from the light source and distribute the light in a uniform pattern; a relay lens system including two or more rotatable anamorphic lenses, the anamorphic lenses being tilted about an optical axis to simultaneously convert the uniform pattern of light into an image having a specified aspect ratio and pre-distort the image; and at least one spatial light modulator configured to receive the pre-distorted image and direct a spatially modulated image onto a light path; at least one projection lens configured to receive the spatially modulated image from the optical path and project the spatially modulated image onto an image plane with the specified aspect ratio; A system including: (EEE2) The system described in EEE1, wherein the light source is one or more lasers. (EEE3) The system described in EEE1 or EEE2, wherein the light integrator is a rectangular integrator rod and the corrected image has a substantially rectangular shape. (EEE4) A system described in any of EEE1 to EEE3, wherein the light integrator has an aspect ratio of approximately 2.08:1, the anamorphic lens has a compression ratio of approximately 1.13:1, and the pre-distorted image received by the spatial light modulator has an aspect ratio of approximately 1.85:1 or approximately 2.35:1. (EEE5) The system described in any of EEE1 to EEE4, wherein the anamorphic lenses are configured to be rotated together to a first angular position to stretch the image vertically, and then rotated together to a second angular position to stretch the image horizontally. (EEE6) The system described in any of EEE1 to EEE5, wherein at least one of the anamorphic lenses has at least one convex surface arranged perpendicular to the optical axis. (EEE7) The system described in any one of EEE1 to EEE6, wherein at least one of the anamorphic lenses is a cylindrical lens. (EEE8) The system described in any one of EEE1 to EEE7, further comprising a lens control unit that controls the rotation of one or more of the anamorphic lenses about the optical axis. (EEE9) The system described in any of EEE1 to EEE9, further including one or more processors in communication with the lens control unit, the one or more processors instructing the control unit to rotate one or more of the anamorphic lenses around the optical axis and controlling reflection of the pre-distorted image by the spatial light modulator. (EEE10) The system according to any one of EEE1 to EEE9, wherein the spatial light modulator is a digital micromirror device. (EEE11) The system of any of EEE1 to 10, wherein the specified aspect ratio is in accordance with the Digital Cinema Initiative (DCI) illumination format specification. (EEE12) An optical projection system, comprising: A light source and a light integrator configured to receive light from the light source and distribute the light in a uniform pattern; a relay lens system including two or more rotatable anamorphic lenses, the anamorphic lenses being tilted about an optical axis to convert the uniform pattern of light into an image having a specified aspect ratio; and at least one spatial light modulator configured to receive the image and direct a spatially modulated image onto a light path; at least one projection lens configured to receive the spatially modulated image from the optical path and project the spatially modulated image onto an image plane with the specified aspect ratio; A system including: (EEE13) The system described in EEE12, wherein the anamorphic lenses are configured to be rotated together to an angular position to stretch the image vertically, and then rotated together to a second angular position to stretch the image horizontally. (EEE14) The system according to any one of EEE12 to 13, wherein the optical integrator is a lens array. (EEE15) The system according to any one of EEE12 to 14, wherein the spatial light modulator is a transmissive liquid crystal display (LCD) panel or a liquid crystal on silicon (LCoS).

Claims

1. 1. A digital light processing (DLP) projection system comprising: A light source and a rectangular integrator rod configured to receive light from the light source and distribute the light in a uniform rectangular pattern; a relay lens system including at least first and second rotatable anamorphic lenses, the first and second anamorphic lenses being tilted about an optical axis to receive the uniform rectangular pattern of light and change an aspect ratio of the uniform rectangular pattern of light, the first anamorphic lens being rotated by less than 90 degrees relative to the second anamorphic lens, the first and second anamorphic lenses adding a parallelogram distortion to the shape of the uniform rectangular pattern of light to produce pre-distorted light having a non-rectangular parallelogram shape; at least one rectangular spatial light modulator configured to receive the pre-distorted light and spatially modulate the pre-distorted light, the rectangular spatial light modulator being illuminated by the pre-distorted light at an illumination angle θ such that the parallelogram distortion is canceled, the rectangular spatial light modulator being configured to direct a spatially modulated image having a rectangular shape onto a light path; at least one projection lens configured to receive the spatially modulated image from the optical path and project the spatially modulated image onto an image plane with a specified aspect ratio; Including, the system.

2. The system of claim 1 , wherein the light source is one or more lasers.

3. 3. The system of claim 1, wherein the rectangular integrator rod has an aspect ratio of approximately 2.08:1, the first and second anamorphic lenses have a compression ratio of approximately 1.13:1, and the pre-distorted light received by the rectangular spatial light modulator has an aspect ratio of approximately 1.85:1 or approximately 2.35:

1.

4. 4. The system of claim 1, wherein the first and second anamorphic lenses are configured to be rotated together to a first angular position to stretch the image vertically, and then rotated together to a second angular position to stretch the image horizontally.

5. The system of any one of claims 1 to 4, wherein at least one of the first and second anamorphic lenses has at least one convex surface disposed perpendicular to the optical axis.

6. A system according to any preceding claim, wherein θ is nominally 24 degrees.

7. The system of any one of claims 1 to 6, further comprising a lens control unit that controls rotation of two or more of the first and second anamorphic lenses about the optical axis.

8. 8. The system of claim 7, further comprising one or more processors in communication with the lens control, the one or more processors instructing the lens control to rotate two or more of the first and second anamorphic lenses about the optical axis to control reflection of the pre-distorted light by the rectangular spatial light modulator.

9. The system of any one of claims 1 to 8, wherein the rectangular spatial light modulator is a digital micromirror device (DMD).

10. The system of any of claims 1 to 9, wherein the specified aspect ratio complies with the Digital Cinema Initiative (DCI) illumination format specification.

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