Optical Architecture for a Beam Steering Projector

Abstract

A beam steering projection system includes a light source configured to emit light in response to an image signal, a phase light modulator, and a spatial light modulator. The phase light modulator is configured to receive light from the light source, apply a spatially varying phase modulation to the light, thereby steering the light at a certain illumination angle and generating a first steered light. The spatial light modulator is configured to receive the first steered light, apply a spatially varying amplitude modulation to the light, steer the light toward a projection optical system, and generate a second steered light. The plane of the secondary image constructed after the phase light modulator and before the spatial light modulator is parallel to the phase light modulator.

Description

Technical Field

[0001] Cross - reference to related applications. This application claims priority from the following priority - claiming applications, namely, U.S. Provisional Application No. 63 / 345,473 (Docket No. D21066USP1) filed on May 25, 2022, and European Patent Application No. 22175389 (Docket No. D21066EP) filed on May 25, 2022.

[0002] 1. Field of the Disclosure This application generally relates to projection systems and optical components within a projection system.

Background Art

[0003] 2. Description of Related Art Digital projection systems typically utilize a light source and an optical system to project an image onto a surface or screen. The optical system includes components such as mirrors, lenses, waveguides, optical fibers, beam splitters, diffusers, spatial light modulators (SLMs), phase light modulators (PLMs), etc. Some optical systems include a light - steering pre - modulator that effectively modulates the phase of light, followed by a second modulator that effectively modulates the amplitude of light. These modulators can be configured as digital light processors (DLPs), digital micromirror devices (DMDs), liquid crystal on silicon (LCOS) modulators, or another suitable modulator.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Both DLP and PLM can be configured as a Digital Micromirror Device (DMD) that includes a plurality of micromirrors for manipulating light. Algorithms for controlling DLP modulate light by independently tilting each micromirror either to direct light along a desired optical path or away from a desired optical path towards a "light dump". Algorithms for controlling PLM modulate light by independently moving each micromirror up and down relative to the PLM housing and adjusting the phase of the light. Other algorithms for controlling PLM modulate light by controlling the refractive index of a liquid crystal medium. Both DLP and PLM have a theoretically optimal illumination angle where the quality of the directed light is maintained and distortion is reduced. Embodiments described herein utilize a reconstruction plane of an image generated by a first modulator in an optical path to improve the optical efficiency of an optical system.

[0005] Various aspects of the present disclosure relate to devices, systems, and methods for projection displays.

Means for Solving the Problems

[0006] In an exemplary aspect of the present disclosure, there is provided a beam steering projection system comprising a light source configured to emit light in response to an image signal, a phase light modulator, and a spatial light modulator. The image signal includes image data. The phase light modulator is configured to receive light from the light source and apply a spatially varying phase modulation to the light, thereby steering the light at an illumination angle to generate a first steered light. The spatial light modulator is configured to receive the first steered light, apply a spatially varying amplitude modulation to the light, and steer the light towards a projection optical system to generate a second steered light. A plane of a secondary image constructed after the phase light modulator and before the spatial light modulator is parallel to the phase light modulator.

[0007] In another exemplary aspect of the present disclosure, a beam steering projection system is provided that includes a light source, a first modulator, an imaging relay optical system, and a second modulator. The light source is configured to emit light. The first modulator receives light from the light source and applies a spatially varying phase modulation to the light, thereby steering the light to a first illumination angle and generating first steered light. The imaging relay optical system receives the first steered light and is configured to generate second steered light at a second illumination angle. The second modulator receives the second steered light and applies a spatially varying amplitude modulation to the light, steering the light toward a projection optical system and generating third steered light. A plane of a secondary image constructed after the first modulator and before the second modulator is parallel to the first modulator.

[0008] In another exemplary aspect of the present disclosure, a method for a beam steering projection system is provided. The projection system includes a light source configured to emit light, a phase light modulator configured to receive light from the light source, apply a spatially varying phase modulation to the light, thereby steering the light to an illumination angle and generating first steered light, and a spatial light modulator configured to receive the first steered light, apply a spatially varying amplitude modulation to the light, thereby steering the light toward a projection optical system. The method includes receiving light from the light source using the phase light modulator and steering the light at an illumination angle using the phase light modulator to generate first steered light. The method further includes constructing a reconstructed image on a reconstructed image plane using the first steered light and receiving the first steered light using the spatial light modulator.

[0009] Thus, various aspects of the present disclosure provide for the display of images having high dynamic range and high resolution, resulting in improvements in at least the technical fields of image projection, holography, signal processing, and the like.

Brief Description of the Drawings

[0010] These and other more detailed and specific features of the various embodiments will be more fully disclosed in the following description with reference to the accompanying drawings.

[0011]

Figure 1

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Figure 2A

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Figure 2B

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Figure 3

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Figure 4

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Figure 5

Best Mode for Carrying Out the Invention

[0017] The present disclosure and aspects thereof can be embodied in various forms including a computer-implemented method, a computer program product, a computer system and network, a user interface, and hardware, a device, or a circuit controlled by an application programming interface; as well as a hardware-implemented method, a signal processing circuit, a memory array, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc. The above summary is only intended to give a general concept of various aspects of the present disclosure and is in no way intended to limit the scope of the present disclosure.

[0018] In the following description, numerous details are set forth in order to provide an understanding of one or more aspects of the present disclosure, such as optical device configuration, timing, operation, etc. It will be readily apparent to those skilled in the art that these specific details are merely examples and are not intended to limit the scope of the present application.

[0019] Furthermore, although the present disclosure mainly focuses on examples where various circuits are used in a digital projection system, it will be understood that this is merely an example of implementation. It should be further understood that the disclosed systems and methods can be used in any device that needs to project light, such as in movie, consumer, and other commercial projection systems, head-up displays, virtual reality displays, etc.

[0020] Projector System

[0021] The light steering modulator can create an image in a plane different from the modulator plane itself. This plane can be a virtual plane or a real plane. The light steering modulator may have flat mirror surfaces and thus typically does not have a specific illumination angle other than some configuration that allows vertical illumination. The light steering modulator can generate an image or object on the modulator itself and can have angled mirrors.

[0022] The optical system described herein optically reconstructs an image with respect to a pre-modulator. The image may be optically reconstructed downstream or optically upstream from the pre-modulator. Under the condition that the reconstructed pre-modulator is parallel to the pre-modulator, the angle between the reconstructed image and the optical axis is controlled according to the illumination angle described in more detail below. The reconstructed pre-modulator image is itself imaged onto the primary modulator, but the object plane in this imaging operation is tilted.

[0023] FIG. 1 shows an exemplary high-contrast projection system 100 according to various aspects of the present disclosure. In particular, FIG. 1 shows a light source 101 configured to emit a first light 102, an illumination optical system 103 (an example of an illumination optical system according to the present disclosure) configured to receive the first light 102, redirect it or otherwise modify it, thereby generating a second light 104, a PLM 105 configured to apply a spatially varying phase modulation to the second light 104, thereby steering the second light 104 and generating a third light 106, a first projection optical system 107 configured to receive the third light 106, redirect it or otherwise modify it, thereby generating a fourth light 108, a DLP 109 configured to modulate the fourth light 108, thereby generating a fifth light 110, and a second projection optical system 111 configured to receive the fifth light 110 and project it onto a screen 113 as a sixth light 112. The DLP 109 may be an amplitude-based SLM or other modulator.

[0024] The projection system 100 further includes a controller 114 configured to control various components of the projection system 100, such as the light source 101, the PLM 105, and / or the DLP 109. In some implementations, the controller 114 may additionally or alternatively control other components of the projection system 100, including but not limited to the illumination optics 103, the first projection optics 107, and / or the second projection optics 111. The controller 114 may be one or more processors, such as a central processing unit (CPU) of the projection system 100. The illumination optics 103, the first projection optics 107, and the second projection optics 111 may each include one or more optical components, such as mirrors, lenses, waveguides, optical fibers, beam splitters, diffusers, and the like. Except for the screen 113, the components shown in FIG. 1 may be integrated into a housing to provide a projection device. Such a projection device may include additional components such as memory, input / output ports, communication circuits, a power supply, and the like.

[0025] The light source 101 may be, for example, a laser light source, an LED, etc. Generally, the light source 101 is any light emitter that emits light. In some implementations, the light is coherent light. In some aspects of the present disclosure, the light source 101 may include a plurality of individual light emitters each corresponding to a different wavelength or wavelength band. The light source 101 may include a dimming device that optically or opto-mechanically dynamically changes the intensity and / or etendue of the emitted light. The light source 101 emits light in response to an image signal provided by a controller 114, such as one or more processors, for example, a central processing unit (CPU) of the projection system 100. The image signal includes image data corresponding to a plurality of frames to be successively displayed. Individual elements within the projection system 100, including the illumination optical system 103 and / or the PLM 105, may be controlled by the controller 114. The image signal may be derived from an external source in a streaming or cloud-based manner, may be derived from an internal memory of the projection system 100, such as a hard disk, may be derived from a removable medium operatively connected to the projection system 100, or may be derived from a combination thereof.

[0026] The first projection optical system 107 and / or the second projection optical system 111 may include a filter to mitigate the effects caused by internal components of the projection system 100. In some systems, the PLM 105 (described in more detail below) includes a cover glass and may cause reflections, device switching may sometimes cause an undesirable steering angle, and various components may cause scattering. To counteract this and reduce the floor level of the projection system 100, the filter may be a Fourier (“DC”) filter component configured to block a portion of the third light 106 and / or the fifth light 110. Thus, the filter can increase the contrast by reducing the floor level from light near zero angle corresponding to elements such as cover glass reflections, stroke transition states, etc. This DC block region may be actively used to prevent certain light from reaching the screen. Further, the filter can mitigate mode noise from a light source 101 (such as a fiber-coupled laser) that has energy at a small angle with respect to most of the light reflected and emitted from the cover glass. An example of reducing cover glass noise is provided in PCT patent application No. PCT / US2020 / 013950, “Attenuated Wavefront Determination for Noise Reduction” by Angelo P. Arrifano and Juan P. Pertierra, which is incorporated herein by reference. In some aspects of the present disclosure, the filter prevents unwanted light from reaching the screen by steering the light to a light dump located outside the active image area in response to control from the controller 114.

[0027] FIG. 1 generally shows a linear optical path, but in reality, the optical path is generally more complex. For example, in projection system 100, the second light 104 from illumination optical system 103 is directed at an oblique angle towards PLM 105, and the fourth light 108 directed from the first projection optical system 107 is directed at an oblique angle towards DLP 109. To ensure that the image on screen 113 has an acceptable clarity and contrast ratio, illumination optical system 103 can be designed and / or controlled to ensure that the angle of incidence on PLM 105 is correct while maintaining the position of the second light 104 centered on PLM 105. PLM 105 and / or the first projection optical system 107 can be designed and / or controlled to ensure that the angle of incidence on DLP 109 is correct while maintaining the position of the fourth light 108 centered on DLP 109.

[0028] Digital Light Processor In some implementations, the DLP 109 is a digital micromirror device (DMD) consisting of a plurality of mirrors used to adjust the angle of incidence of light (e.g., the fourth light 108). To illustrate the angle of incidence and the effect of the DMD mirrors, FIGS. 2A-2B show an exemplary DMD 200 according to various aspects of the present disclosure. In particular, FIG. 2A is a plan view of the DMD 200, and FIG. 2B is a partial cross-sectional view of the DMD 200 taken along line II-B shown in FIG. 2A. The DMD 200 includes a plurality of square micromirrors 202 arranged in a two-dimensional rectangular array on a substrate 204. Each micromirror 202 may correspond to one pixel of the final projected image and may be configured to tilt about a rotation axis 208 shown for one particular subset of the micromirrors 202 by electrostatic or other types of actuations. The individual micromirrors 202 have a width 212 and are arranged with a gap of width 210 therebetween. The micromirrors 202 are formed of or coated with any highly reflective material such as aluminum or silver, thereby being able to specularly reflect light. The gap between the micromirrors 202 may be absorptive or may be such that the input light entering the gap is absorbed by the substrate 204.

[0029] FIG. 2A explicitly shows only some representative micromirrors 202, but in practice, the DMD 200 may include a greater number of individual micromirrors equal to the resolution of the projection system 100. In some examples, the resolution may be 2K (2048×1080), 4K (4096×2160), 1080p (1920×1080), consumer 4K (3840×2160), etc. Further, in some examples, the micromirrors 202 may be rectangular and arranged in a rectangular array; hexagonal and arranged in a hexagonal array, etc. Further, although FIG. 2A shows a rotation axis 208 extending in a diagonal direction, in some implementations, the rotation axis 208 may extend vertically or horizontally.

[0030] As shown in FIG. 2B, each micromirror 202 may be connected to a substrate 204 by a yoke 214 rotatably connected to the micromirror 202. The substrate 204 includes a plurality of electrodes 216. In the cross-sectional view of FIG. 2B, only two electrodes 216 can be seen for each micromirror 202, but each micromirror 202 may actually include additional electrodes. Although not specifically shown in FIG. 2B, the DMD 200 may further include a spacer layer, a support layer, a hinge component for controlling the height or orientation of the micromirror 202, and the like. The substrate 204 can include electronic circuits associated with the DMD 200, such as complementary metal-oxide-semiconductor (CMOS) transistors, memory elements, and the like.

[0031] Depending on the specific operation and control of the electrodes 216, the individual micromirrors 202 can be switched between an "on" position, an "off" position, and an inoperative or neutral position. When the micromirror 202 is in the on position, the micromirror is actuated to an angle of (e.g.) -12° (i.e., rotated 12° counterclockwise with respect to the neutral position) to specularly reflect the input light 206 into the on-state light 218. When the micromirror 202 is in the off position, the micromirror is actuated to an angle of (e.g.) +12° (i.e., rotated 12° clockwise with respect to the neutral position) to specularly reflect the input light 206 into the off-state light 220. The off-state light 220 may be directed towards a light dump that absorbs the off-state light 220. In some cases, the micromirror 202 may be inoperative and parallel to the substrate 204. The specific angles shown in FIGS. 2A-2B and described herein are merely exemplary and not limiting. In some implementations, the on-position angle and the off-position angle may each be between ±11 degrees and ±13 degrees (including both ends). In other implementations, the on-position angle and the off-position angle may each be between ±10 degrees and ±18 degrees (including both ends).

[0032] Phase-Type Light Modulator As shown in FIG. 1, the controller 114 also controls the PLM 105 that receives light from the light source 101. The PLM 105 imparts spatially varying phase modulation to the light and redirects the modulated light toward the first projection optical system 107. The PLM 105 may be a reflective type that reflects incident light having a spatially varying phase of the PLM 105, or alternatively, the PLM 105 may be a transmissive type that imparts a spatially varying phase to the light as the light passes through the PLM 105. In some aspects of the present disclosure, the PLM 15 has a liquid crystal on silicon (LCOS) architecture. In other aspects of the present disclosure, the PLM 105 has a microelectromechanical systems (MEMS) architecture.

[0033] FIG. 3 shows an example of the PLM 105 implemented as a reflective LCOS PLM 300 and shown in a partial cross-sectional view. As shown in FIG. 3, the PLM 300 includes a silicon backplane 310, a first electrode layer 320, a second electrode layer 330, a liquid crystal layer 340, a cover glass 350, and spacers 360. The silicon backplane 310 includes electronic circuits associated with the PLM 300 such as CMOS transistors. The first electrode layer 320 includes an array of reflective elements 321 disposed within a transparent matrix 322. The reflective elements 321 can be formed from any highly light-reflective material such as aluminum or silver. The transparent matrix 322 may be formed from any highly optically transmissive material such as a transparent oxide. The second electrode layer 330 may be formed from any optically transparent conductive material such as a thin film of indium tin oxide (ITO). The second electrode layer 330 can be provided as a common electrode corresponding to a plurality of the reflective elements 321 of the first electrode layer 320. In such a configuration, each of the plurality of reflective elements 321 is coupled to the second electrode layer 330 via its respective electric field, and thus, the PLM 300 is divided into an array of pixel elements. Thus, the individual ones (or subsets) of the plurality of reflective elements 321 are addressed via the electronic circuits disposed on the silicon backplane 310, whereby the state of the corresponding reflective element 321 can be modified.

[0034] The liquid crystal layer 340 is disposed between the first electrode layer 320 and the second electrode layer 330 and includes a plurality of liquid crystals 341. The liquid crystals 341 are particles existing in a phase intermediate between a solid and a liquid. In other words, the liquid crystals 341 exhibit a certain degree of directional order but do not exhibit positional order. The direction in which the liquid crystals 341 tend to face is referred to as the "director". The liquid crystal layer 340 modifies the light incident from the cover glass 350 based on the birefringence Δn of the liquid crystals 341 (which can be expressed as the difference between the refractive index in the direction parallel to the director and the refractive index in the direction perpendicular to the director). From this, the maximum optical path difference may be expressed as the product of the birefringence and the thickness of the liquid crystal layer 240. The thickness is set by the spacer 260 that seals the PLM 300 and guarantees a set distance between the cover glass 350 and the silicon backplane 310. The liquid crystals 341 generally align along the electric field lines between the first electrode layer 320 and the second electrode layer 330. As shown in FIG. 3, the liquid crystals near the center of the PLM 300 are aligned in this way, while the liquid crystals 241 near the periphery of the PLM 300 are substantially unaligned when there are no electric field lines. By addressing each of the plurality of reflective elements 321 via a phase drive signal, the alignment of the liquid crystals 341 can be determined for each pixel.

[0035] FIG. 4 shows another example of the PLM 105 implemented as a DMD PLM 400 and shown in a partial cross-sectional view. As shown in FIG. 4, the PLM 400 includes a backplane 410 and a plurality of controllable reflective elements as pixel elements, and each of the pixel elements includes a yoke 421, a mirror plate 422, and a pair of electrodes 430. Although only two electrodes 430 can be seen in the cross-sectional view of FIG. 4, each reflective element may actually include additional electrodes. Although not specifically shown in FIG. 4, the PLM 400 may further include a spacer layer, a support layer, a hinge component for controlling the height or orientation of the mirror plate 422, etc. The backplane 410 includes electronic circuits related to the PLM 400, such as CMOS transistors, memory arrays, etc.

[0036] The yoke 421 can be formed of, or include, an electrically conductive material so as to enable a bias voltage to be applied to the mirror plate 422. The mirror plate 422 may be formed of any highly reflective material such as aluminum or silver. The electrodes 430 are configured to receive a first voltage and a second voltage respectively and may be individually addressable. Depending on the values of the voltage on the electrodes 430 and the voltage on the mirror plate 422 (e.g., the bias voltage), a potential difference exists between the mirror plate 422 and the electrodes 430, which generates an electrostatic force acting on the mirror plate 422. The yoke 421 is configured to allow vertical movement of the mirror plate 422 in response to the electrostatic force. The equilibrium position of the mirror plate 422 that occurs when the electrostatic force is equal to the spring-like force of the yoke 421 determines the optical path length of the light reflected from the upper surface of the mirror plate 422. Thus, each of the plurality of controllable reflective elements is controlled to provide several (three in the figure) discrete heights, and thus several discrete phase configurations or phase states. As shown, each of the phase states has a flat profile. In some aspects of the present disclosure, the electrodes 430 may be given different voltages to impart an inclination to the mirror plate 422. Such an inclination may be utilized with the type of optical damper described above.

[0037] The PLM 400 can have a high switching speed such that the PLM 400 switches from one phase state, for example, on the order of tens of μs. To provide a complete cycle of phase control, the total optical path difference between the state where the mirror plate 422 is at its highest point and the state where the mirror plate 422 is at its lowest point should be approximately equal to the wavelength λ of the incident light. Thus, the height range between the highest point and the lowest point should be approximately equal to λ / 2.

[0038] In some implementations, the PLM 105 generates a fixed diffraction order, and the mirror plate 422 generates a plurality of “copies” of the light that impinges on the mirror plate. The PLM 105 steers the light within each diffraction order range to generate a plurality of image “copies” in the reconstruction plane. The images steered by the PLM 105 can be formed on the image reconstruction plane at a distance where the diffraction orders are separated without overlapping. In some implementations, the image reconstruction plane is closer to the PLM 105 to reduce blurring of the reconstructed images. A Fourier filter is implemented with the PLM 105 to remove diffraction order overlap in the image reconstruction plane. In some implementations, the diffraction patterns interfere with each other constructively to form the reconstructed image. Thus, if a portion of the light steered by the PLM 105 is blocked, the reconstructed image will be blurred compared to the reconstructed image that includes all of the light from the PLM 105.

[0039] Optical Architecture One exemplary implementation of the present disclosure provides an optical system having a first optical steering premodulator, such as a PLM, followed by a second modulator, such as a DLP. FIG. 5 shows an exemplary optical state of a partial optical system 500 according to the present disclosure. The partial optical system 500 may be at least partially an example of the projection system 100.

[0040] In particular, FIG. 5 shows a light source 501, a first light 502, an illumination optical system 503, a second light 504, a first modulator 505, a third light 506, an illumination relay optical system 507, a fourth light 508, a second modulator 509, a fifth light 510, a second projection optical system 511, a sixth light 512, and a light output 513. The various elements shown in FIG. 5 may correspond to the various elements (or portions of the various elements) shown in FIG. 1. In some implementations, the first modulator 505 is a PLM device and the second modulator 509 is a DLP device. In other implementations, the first modulator 505 is a DLP device and the second modulator 509 is a PLM device. In some implementations, the first modulator 505 is within a prism, such as a prism that converts light in the RGB color region to white light for modulation. In some examples, the second modulator 509 is within a prism 521, such as a prism that converts light in the RGB color region to white light.

[0041] In the implementation shown in FIG. 5, the illumination optical system 503 includes a first diffuser 514, a first lens 515, and a second lens 516. The first diffuser 514 may modify the first light 502 and generate a desired point-spread-function (PSF) for the second light 504 received by the first modulator 505. In some implementations, the first diffuser 514 is synchronized with the first modulator 505 and / or the second modulator 509. Additionally, in some examples, the first diffuser 514 is rotating. In other examples, the first diffuser 514 is fixed. In some implementations, the first diffuser 514 may blur the image projected by the light source 501 and prevent the need for exact alignment requirements.

[0042] Although shown as including two lenses, the illumination optical system 503 may be composed of any number of lenses to direct the first light 502 toward the first modulator 505 at a predetermined illumination angle θ. Also, although each individual lens is shown separately, the individual lenses may be joined to each other. Further, each lens group may be composed of any type of lens, such as a concave lens, a collimator lens, a negative meniscus lens, a positive meniscus lens, etc.

[0043] In the implementation shown in FIG. 5, the illumination relay optical system 507 (for example, an imaging relay optical system) includes a third lens 518, a first filter 519, and a fourth lens 520. In other implementations, the illumination relay optical system 507 may not include the first filter 519. The first filter 519 may include an aperture configured to pass a predetermined diffraction order or a predetermined illumination angle of the third light 506. For example, the first filter 519 may include a "Fourier section" or a "Fourier lens assembly" that refers to an optical system that spatially Fourier-transforms the modulated light by converging the modulated light (for example, the light from the first modulator 505) onto the Fourier plane. The spatial Fourier transform imposed by the Fourier section converts the propagation angle of each diffraction order of the modulated light to a corresponding spatial position on the Fourier plane. Thereby, the Fourier section enables the selection of the desired diffraction orders and the rejection of the undesired diffraction orders by spatial filtering on the Fourier plane. For example, the Fourier section may be configured to pass light projected at an angle of 12°. The spatial Fourier transform of the modulated light on the Fourier plane is equivalent to the Fraunhofer diffraction pattern of the modulated light. In some implementations, the first filter 519 blocks the light components that raise the black level, thereby lowering the black level and improving the effective contrast ratio of the first modulator 505. In some implementations, the first filter 519 is optically positioned between the first modulator 505 and the third lens 518 to improve the characteristics of the light modulated by the first modulator 505.

[0044] Although shown as including two lenses, the illumination relay optical system 507 may be composed of any number of lenses for directing the fourth light 508 toward the second modulator 509 at a second predetermined illumination angle φ. Also, although each individual lens is shown separately, the individual lenses may be joined to each other. In some examples, the third lens 518 and the fourth lens 520 may be composed of several lenses forming a lens group. Also, each lens or lens group may be composed of any type of lens, such as a concave lens, a negative meniscus lens, a positive meniscus lens, etc.

[0045] In the implementation of FIG. 5, the second projection optical system 511 includes a fifth lens 523, a sixth lens 524, a second filter 525, a seventh lens 526, and an eighth lens 527. In other implementations, the second projection optical system 511 may not include the second filter 525. The second filter 525 may be functionally similar to the first filter 519 (for example, including a "Fourier section"). In some implementations, the second filter 525 is configured to improve the black level of the second modulator 509. In some implementations, the optical system 500 includes a window actuator 522 optically positioned between the second modulator 509 and the second projection optical system 511. The window actuator 522 is configured to increase the resolution of an image (for example, the fifth light 510) reflected by the second modulator 509. For example, the window actuator 522 can upscale an image reflected by the second modulator 509 from a 720p image to a 1080p image, from a 1080p image to a 2K image, from a 2K image to a 4K image, etc.

[0046] In some implementations, the optical system 500 includes a second diffuser 517. The second diffuser 517 may define a plane (e.g., the reconstructed image plane) in which the image from the first modulator 505 is reconstructed. In some implementations, the reconstructed image plane is parallel to the first modulator 505. The second diffuser 517 may also add angular diversity to the third light 506 after the image is reconstructed, reducing the effects of dust and other obstacles within the optical system 500. In some implementations, the second diffuser 517 is synchronized with the first modulator 505 and / or the second modulator 509. Additionally, in some examples, the second diffuser 517 is rotating. In other examples, the second diffuser 517 is fixed.

[0047] In other implementations, the reconstructed image plane is separate from the second diffuser 517. For example, the reconstructed image plane may be located optically upstream or optically downstream of the second diffuser 517. In implementations where the optical system 500 does not include the second diffuser 517, the reconstructed image plane may be located optically upstream or optically downstream of the illumination relay optics 507 and optically between the first modulator 505 and the second modulator 509. Further, in some implementations, the reconstructed image plane may be angularly offset from the first modulator 505. In such implementations, the illumination relay optics 507 may be configured to control the third light 506 such that the reconstructed image contacts the second modulator 509 at a desired angle. For example, the image plane of the illumination relay optics 507 between the second diffuser 517 and the second modulator 509 is tilted to correspond to the second illumination angle φ, i.e., the illumination angle of the second modulator 509. This provides a focused image of the reconstructed image across the surface of the second modulator 509. In other implementations, a glass piece or additional lens such as an inclined or decentered lens element or a glass prism element is utilized to tilt the reconstructed image plane such that the reconstructed image contacts the second modulator 509 at a desired angle.

[0048] In some implementations, the image reconstruction plane is optically in front of the first modulator 505. For example, the image reconstruction plane may be located on the first diffuser 514 or optically between the first modulator 505 and the first diffuser 514. In such an implementation, the image reconstruction plane may be virtual so as to be visible from downstream of the first modulator 505.

[0049] The angle between the reconstructed image formed on the reconstruction image plane and the optical axis is controlled by the first illumination angle θ. The reconstructed image from the first modulator 505 is then imaged onto the second modulator 509, but the plane of the second modulator 509 is tilted with respect to the reconstruction image plane. To account for this tilt in the reconstructed image, in some implementations, the first illumination angle θ is selected to satisfy the Scheimpflug criteria of the second modulator 509. As described above, when the second modulator 509 is a DMD, the micromirror 202 is tilted by approximately 12°. In such an implementation, the first illumination angle θ is selected to be approximately 24°. In an implementation where the second modulator 509 is a DLP, the second modulator has a mirror tilted obliquely (i.e., at an azimuth tilt of 45°). In this scenario, the first illumination angle θ at the first modulator 505 is also selected to be 45°. By selecting the first illumination angle θ to satisfy the Scheimpflug criteria, the reconstructed image is in perfect focus on the second modulator 509. In other implementations, the second illumination angle φ is selected to be approximately 24°. In a situation where the first modulator 505 and the second modulator 509 include prisms, their respective illumination angles can be selected taking into account the geometric shape of the prisms.

[0050] In some embodiments, the distortion of the reconstructed image results in an image having a trapezoidal shape on the second modulator 509. Since the trapezoidal shape does not fit the rectangular shape of the second modulator 509, such distortion hinders the efficient filling of the second modulator 509. Thus, the first illumination angle θ is selected such that the reconstructed image provided by the first modulator 505 is approximately rectangular on the second modulator 509, and improved optical efficiency can be achieved. In some implementations, the reconstructed image provided by the first modulator 505 is distorted such that the image is approximately rectangular on the second modulator 509.

[0051] To achieve or adjust the first illumination angle θ, the positions of the light source 501, the illumination optics 503, the first modulator 505, the illumination relay optics 507, and the second modulator 509 can be set during the construction of the optical system 500. In some implementations, the positions of the light source 501, the illumination optics 503, and the illumination relay optics 507 can be set or adjusted to change the first illumination angle θ using respective tracks and actuators controlled by the controller 114. In some implementations, the reflection characteristics of the illumination optics 503 and the illumination relay optics 507 are electrically controlled by the controller 114 to change the first illumination angle θ.

[0052] In some embodiments, the optical system 500 represents only a single color channel of the projection system 100. Thus, each color channel within the projection system 100 may have its own optical system configured similarly to the optical system 500, each having its own PLM 105 and DLP 109. The color channels can be combined following their respective light outputs 513 before being projected onto the screen 113. The light output 513 may be a three-channel prism as seen in U.S. Patent No. 10,197,902, "High Contrast Discrete Input Prism for Image Projectors", which is hereby incorporated by reference in its entirety.

[0053] The above projection system can provide an optical configuration that improves the efficiency of the second modulator by using the reconstructed image plane of the image reflected by the first modulator.

[0054] The systems, methods, and devices according to the present disclosure can take any one or more of the following configurations.

[0055] (1) A light source configured to emit light in response to an image signal including image data; a phase light modulator configured to receive the light from the light source and apply a spatially varying phase modulation to the light, thereby steering the light to an illumination angle and generating a first steered light; and a spatial light modulator configured to receive the first steered light, apply a spatially varying amplitude modulation to the light, and steer the light toward a projection optical system to generate a second steered light, wherein a plane of a secondary image constructed after the phase light modulator and before the spatial light modulator is parallel to the phase light modulator. A beam steering projection system comprising a spatial light modulator.

[0056] (2) The beam steering projection system according to (1), wherein the illumination angle satisfies the shine-through criterion with respect to the spatial light modulator.

[0057] (3) The beam steering projection system according to any one of (1) to (2), further comprising a diffuser optically disposed between the phase light modulator and the spatial light modulator.

[0058] (4) The beam steering projection system according to (3), wherein the secondary image is constructed in the diffuser.

[0059] (5) The beam steering projection system according to any one of (1) to (4), further comprising a filter optically disposed between the phase light modulator and the spatial light modulator, the filter being configured to increase an effective contrast ratio of the first steered light.

[0060] (6) Further comprising a diffuser optically disposed between the light source and the phase light modulator, the diffuser being configured to generate a preconfigured point spread function of the light, the beam steering projection system according to any one of (1) to (5).

[0061] (7) Further comprising a filter optically disposed behind the spatial light modulator, the filter being configured to reduce the black level of the second steered light, the beam steering projection system according to any one of (1) to (6).

[0062] (8) The spatial light modulator is disposed within a prism, the beam steering projection system according to any one of (1) to (7).

[0063] (9) A light source configured to emit light; a first modulator configured to receive the light from the light source, apply a spatially varying phase modulation to the light, thereby steering the light to a first illumination angle and generating a first steered light; an imaging relay optical system configured to receive the first steered light and generate a second steered light at a second illumination angle; and a second modulator configured to receive the second steered light, apply a spatially varying amplitude modulation to the light, steer the light toward a projection optical system, and generate a third steered light, wherein a plane of a secondary image constructed after the first modulator and before the second modulator is parallel to the first modulator, the beam steering projection system.

[0064] (10) The first modulator and the second modulator are digital micromirror devices, the beam steering projection system according to (9).

[0065] The beam steering projection system according to any one of (9) to (10), further comprising a first diffuser optically disposed between the first modulator and the second modulator.

[0066] The beam steering projection system according to any one of (9) to (11), further comprising a filter optically disposed between the first modulator and the second modulator, the filter being configured to increase an effective contrast ratio of the first steering light.

[0067] The beam steering projection system according to (12), wherein the filter is optically disposed between the first modulator and the imaging relay optical system.

[0068] The beam steering projection system according to any one of (9) to (13), further comprising a diffuser optically disposed between the light source and the first modulator, the diffuser being configured to generate a preconfigured point spread function of the light.

[0069] The beam steering projection system according to any one of (9) to (14), further comprising a filter optically disposed after the second modulator, the filter being configured to reduce a black level of the third steering light.

[0070] The beam steering projection system according to any one of (9) to (15), further comprising a window actuator optically disposed between the second modulator and the projection optical system and configured to increase a resolution of an image defined by the third steered light.

[0071] The beam steering projection system according to any one of (9) to (16), further comprising a diffuser optically disposed between the first modulator and the second modulator, the secondary image being constructed at the diffuser.

[0072] (18) A method for a beam steering projection system, the beam steering projection system comprising: a light source configured to emit light; a phase light modulator configured to receive the light from the light source, apply a spatially varying phase modulation to the light, thereby steering the light to an illumination angle and generating a first steered light; and a spatial light modulator configured to receive the first steered light, apply a spatially varying amplitude modulation to the light, thereby steering the light toward a projection optical system, the method comprising: receiving the light from the light source using the phase light modulator; steering the light at the illumination angle using the phase light modulator to generate the first steered light; constructing a reconstructed image on a reconstructed image plane using the first steered light; and receiving the first steered light using the spatial light modulator.

[0073] (19) The beam steering projection system further comprises a filter optically disposed between the phase light modulator and the spatial light modulator, and the method further comprises increasing an effective contrast ratio of the first steered light using the filter, the method according to (18).

[0074] (20) A non-transitory computer-readable medium storing instructions that, when executed by a processor of a beam steering projection system, cause the beam steering projection system to perform operations including the method according to any one of (18) to (19).

[0075] (21) The beam steering projection system according to any one of (12) or (13), or (14) to (17) when dependent on (12) or (13), wherein the filter is configured to block light components that increase a black level.

[0076] (22) The filter is configured to block one or more diffraction orders of the first steered light, the beam steering projection system according to any one of (21), (12), (13), or (14) to (17) when dependent on (12) or (13).

[0077] Regarding the processes, systems, methods, heuristics, etc. described herein, although the steps of such processes, etc. are described as occurring according to a certain ordered sequence, it should be understood that such processes can be implemented using the described steps in an order other than that described herein. Furthermore, it should be understood that certain steps can be executed simultaneously, other steps can be added, or certain steps described herein can be omitted. In other words, the description of the processes herein is provided for the purpose of explaining certain embodiments and should in no way be construed as limiting the claims.

[0078] Thus, it should be understood that the above description is illustrative and not restrictive. Many embodiments and applications other than the examples provided will become apparent upon reading the above description. The scope should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled, rather than with reference to the above description. Future developments may occur in the technologies discussed herein, and it is expected and intended that the disclosed systems and methods will be incorporated into such future embodiments. In short, it should be understood that this application is capable of modification and change.

[0079] All terms used in the claims are intended to be given the broadest reasonable interpretation and their ordinary meaning as understood by one of ordinary skill in the art to which the technology described herein pertains, unless explicitly stated otherwise herein. In particular, the use of singular articles such as "a", "the", "said", etc. should be read as reciting one or more of the indicated elements unless the claim expressly recites a contrary limitation.

[0080] The summary of the disclosure is provided to enable the reader to quickly ascertain the nature of the technical disclosure. The summary is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Further, in the foregoing detailed description, for the purposes of improving the flow of the disclosure, it can be seen that various features are grouped together in various embodiments. This method of disclosure should not be interpreted as reflecting an intention that the embodiments recited in the claims incorporate more features than are expressly recited in each claim. Rather, as the claims reflect, the inventive subject matter lies in less than all of the features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the detailed description herein, and each claim stands on its own as a separately claimed subject matter.

Claims

1. A light source configured to emit light in response to an image signal including image data; A phase light modulator configured to receive the light from the light source, apply a spatially varying phase modulation to the light, thereby steering the light at a first illumination angle to generate a first steered light; A spatial light modulator configured to receive the first steered light, apply a spatially varying amplitude modulation to the light, steer the light toward a projection optical system, and generate a second steered light, wherein a plane of a secondary image constructed after the phase light modulator and before the spatial light modulator is parallel to the phase light modulator, A beam steering projection system.

2. The beam steering projection system according to claim 1, further comprising a diffuser optically disposed between the phase light modulator and the spatial light modulator.

3. The beam steering projection system according to claim 2, wherein the secondary image is constructed in the diffuser.

4. The beam steering projection system according to any one of claims 1 to 3, further comprising a filter optically disposed between the phase light modulator and the spatial light modulator, the filter being configured to increase an effective contrast ratio of the first steered light and block one or more diffraction orders of the first steered light.

5. The beam steering projection system according to any one of claims 1 to 4, further comprising a diffuser optically disposed between the light source and the phase light modulator, the diffuser being configured to generate a preconfigured point spread function of the light.

6. The beam steering projection system according to any one of claims 1 to 5, further comprising a filter optically disposed after the spatial light modulator, the filter being configured to reduce a black level of the second steered light.

7. A light source configured to emit light; A first modulator configured to receive the light from the light source, apply a spatially varying phase modulation to the light, thereby steering the light at a first illumination angle to generate a first steered light; An imaging relay optical system configured to receive the first steered light and generate second steered light at a second illumination angle; A second modulator configured to receive the second steered light, apply a spatially varying amplitude modulation to the light, steer the light towards a projection optical system, and generate third steered light, The plane of the secondary image constructed after the first modulator and before the second modulator is parallel to the first modulator, A beam steering projection system.

8. The beam steering projection system according to claim 7, further comprising a first diffuser optically disposed between the first modulator and the second modulator.

9. The beam steering projection system according to claim 7 or 8, further comprising a filter optically disposed between the first modulator and the second modulator, the filter being configured to increase the effective contrast ratio of the first steered light.

10. The beam steering projection system according to claim 9, wherein the filter is configured to block light components that raise the black level and / or block one or more diffraction orders of the first steered light.

11. The beam steering projection system according to claim 9 or 10, wherein the filter is optically disposed between the first modulator and the imaging relay optical system.

12. The beam steering projection system according to any one of claims 7 to 11, further comprising a diffuser optically disposed between the light source and the first modulator, the diffuser being configured to generate a preconfigured point spread function of the light.

13. The beam steering projection system according to any one of claims 7 to 11, further comprising a diffuser optically disposed between the first modulator and the second modulator, the secondary image being constructed at the diffuser.

14. A method for a beam steering projection system, the beam steering projection system including a light source configured to emit light, a phase light modulator configured to receive the light from the light source, apply a spatially varying phase modulation to the light, thereby steering the light at an illumination angle to generate a first steered light, and a spatial light modulator configured to receive the first steered light, apply a spatially varying amplitude modulation to the light, thereby steering the light toward a projection optical system. The method includes: receiving, using the phase light modulator, the light from the light source; steering, using the phase light modulator, the light at the illumination angle to generate the first steered light; constructing, using the first steered light, a reconstructed image on a reconstructed image plane; receiving, using the spatial light modulator, the first steered light. Claim 15 The beam steering projection system further includes a filter optically disposed between the phase light modulator and the spatial light modulator. The method includes: increasing, using the filter, an effective contrast ratio of the first steered light; further including blocking, using the filter, one or more diffraction orders of the first steered light. The method according to claim 14. Claim 16 A non-transitory computer-readable medium storing instructions that, when executed by a processor of a beam steering projection system, cause the beam steering projection system to perform operations including the method according to any one of claims 14 to 15.

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