Optical architecture for beam steering projectors

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 and apply spatially varying phase modulation to the light to steer the light at an illumination angle and produce a first steered light. The spatial light modulator is configured to receive the first redirected light, apply a spatially varying amplitude modulation to the light, redirect the light toward the projection optical system, and generate a second redirected 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

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the following priority applications: U.S. Provisional Application No. 63 / 345,473 filed on May 25, 2022 (reference number D21066USP1) and European Patent Application No. 22175389 filed on May 25, 2022 (reference number D21066EP). background 1. Technical Field

[0003] The present application relates generally to projection systems and optical configurations within projection systems. 2. Background technology

[0004] 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), and the like. Some optical systems include a light steering pre-modulator that effectively modulates the phase of the light, followed by a second modulator that effectively modulates the amplitude of the light. The modulator can be configured as a digital light processor (DLP), a digital micromirror device (DMD), a liquid crystal on silicon (LCOS) modulator, or another suitable modulator. Summary of the invention

[0005] Both DLP and PLM can be configured as digital micromirror devices (DMDs), which include multiple micromirrors to manipulate light. The algorithm for controlling DLP modulates the light by independently tilting each micromirror to direct the light toward the desired optical path, or to direct the light away from the desired optical path and toward a "light collector". The algorithm for controlling PLM modulates the light by independently moving each micromirror up or down relative to the PLM housing, thereby adjusting the phase of the light. Other algorithms for controlling PLM modulate light by controlling the refractive index of the liquid crystal medium. Both DLP and PLM have a theoretical optimal illumination angle, at which the quality of the diverted light is maintained and distortion is reduced. The embodiments described herein utilize a reconstruction plane of an image created by a first modulator in the optical path to improve the optical efficiency of the optical system.

[0006] Various aspects of the present disclosure relate to devices, systems, and methods for projection display.

[0007] In an exemplary aspect of the present disclosure, a beam steering projection system is provided, which includes 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 spatially varying phase modulation to the light, so that the light is turned at an illumination angle and a first turned light is generated. The spatial light modulator is configured to receive the first turned light, apply spatially varying amplitude modulation to the light, turn the light toward the projection optical system and generate a second turned 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.

[0008] In another exemplary aspect of the present disclosure, a beam steering projection system is provided, which includes a light source, a first modulator, an imaging relay optical device, and a second modulator. The light source is configured to emit light. The first modulator is configured to receive light from the light source and apply spatially varying phase modulation to the light, thereby steering the light at a first illumination angle and generating a first steering light. The imaging relay optical device is configured to receive the first steering light and generate a second steering light at a second illumination angle. The second modulator is configured to receive the second steering light, apply spatially varying amplitude modulation to the light, steering the light toward the projection optical system and generating a third steering light. The plane of the secondary image constructed after the first modulator and before the second modulator is parallel to the first modulator.

[0009] 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 and apply spatially varying phase modulation to the light, thereby steering the light at an illumination angle and generating a first steering light; and a spatial light modulator configured to receive the first steering light and apply spatially varying amplitude modulation to the light, thereby steering the light toward the projection optical system. The method includes: receiving light from the light source using a phase light modulator; and steering the light at an illumination angle to generate a first steering light using the phase light modulator. The method also includes: constructing a reconstructed image on a reconstructed image plane using the first steering light; and receiving the first steering light using the spatial light modulator.

[0010] In this way, various aspects of the present disclosure provide for the display of images with high dynamic range and high resolution, and provide effective improvements in at least the technical fields of image projection, holography, signal processing, and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] These and other more detailed and specific features of various embodiments are more fully disclosed in the following description with reference to the accompanying drawings, in which:

[0012] Figure 1 illustrates a block diagram of an exemplary projection system according to various aspects of the present disclosure;

[0013] Figure 2A illustrates a plan view of an exemplary spatial light modulator for use with various aspects of the present disclosure;

[0014] Figure 2B The diagram shows Figure 2A A cross-sectional view taken along line II-B;

[0015] Figure 3 illustrates a plan view of an exemplary phase light modulator for use with various aspects of the present disclosure;

[0016] Figure 4 illustrates a cross-sectional view of another exemplary phase light modulator for use with various aspects of the present disclosure; and

[0017] Figure 5 Exemplary optical conditions in an exemplary projection system according to various aspects of the present disclosure are illustrated. DETAILED DESCRIPTION

[0018] The present disclosure and its various aspects may be implemented in various forms, including: hardware, devices or circuits controlled by computer-implemented methods, computer program products, computer systems and networks, user interfaces and application programming interfaces; as well as hardware-implemented methods, signal processing circuits, memory arrays, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), etc. The foregoing summary is intended only to give a general idea of ​​the various aspects of the present disclosure and is not intended to limit the scope of the present disclosure in any way.

[0019] In the following description, many details such as optical device configuration, timing, operation, etc. are set forth to provide an understanding of one or more aspects of the present disclosure. It is obvious to those skilled in the art that these specific details are only exemplary and are not intended to limit the scope of the present application.

[0020] In addition, although the present disclosure focuses on examples of using various circuits in digital projection systems, it should be understood that this is only one example of an implementation. It should be further understood that the disclosed systems and methods can be used in any device that needs to project light; for example, theater projection systems, consumer-grade projection systems and other commercial projection systems, head-up displays, virtual reality displays, etc.

[0021] Projector System

[0022] Light steering modulators can create images at a different plane than the modulator plane itself. This plane can be a virtual plane or a real plane. Light steering modulators can have a flat reflective mirror surface, so there is generally no inherent illumination angle except for a certain configuration that allows normal illumination. Light steering modulators can create images or objects on the modulator itself and have angled reflectors.

[0023] The optical system described herein reconstructs an image that corresponds optically to a premodulator. The image can be reconstructed optically downstream or optically upstream of the premodulator. The angle between the reconstructed image and the optical axis is controlled according to the illumination angle, under the condition that the reconstructed premodulator is parallel to the premodulator, as described in more detail below. The reconstructed premodulator image itself is imaged onto the primary modulator, but in this imaging operation, the object plane is tilted.

[0024] Figure 1 An exemplary high contrast projection system 100 according to various aspects of the present disclosure is illustrated. In particular, Figure 1 A projection system 100 is illustrated, comprising: a light source 101 configured to emit a first light 102; an illumination optical device 103 (an example of an illumination optical system according to the present disclosure), the illumination optical device configured to receive the first light 102 and redirect or otherwise modify the first light to produce a second light 104; a PLM 105, the PLM configured to apply a spatially varying phase modulation to the second light 104, thereby turning the second light 104 and producing a third light 106; a first projection optical device 107, the first projection optical device configured to receive the third light 106 and redirect or otherwise modify the third light to produce a fourth light 108; a DLP 109, the DLP configured to modulate the fourth light 108 to produce a fifth light 110; and a second projection optical device 111, the second projection optical device configured to receive the fifth light 110 and project the fifth light as the sixth light 112 onto a screen 113. The DLP 109 may be an amplitude-based SLM or other modulator.

[0025] The projection system 100 also includes a controller 114, which is 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 embodiments, the controller 114 can additionally or alternatively control other components of the projection system 100, including but not limited to the illumination optical device 103, the first projection optical device 107, and / or the second projection optical device 111. The controller 114 can be one or more processors of the projection system 100, such as a central processing unit (CPU). The illumination optical device 103, the first projection optical device 107, and the second projection optical device 111 can each include one or more optical components such as reflectors, lenses, waveguides, optical fibers, beam splitters, diffusers, etc. In addition to the screen 113, Figure 1 The components shown can 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, power supplies, etc.

[0026] The light source 101 may be, for example, a laser light source, an LED, etc. In general, the light source 101 is any light emitter that emits light. In some embodiments, the light is coherent light. In some aspects of the present disclosure, the light source 101 may include a plurality of separate light emitters, each corresponding to a different wavelength or wavelength band. The light source 101 may include a dimming device that dynamically changes the intensity and / or extension of the emitted light in an optical or optical mechanical manner. The light source 101 emits light in response to an image signal provided by a controller 114; the controller is, for example, one or more processors of the projection system 100, such as a central processing unit (CPU). The image signal includes image data corresponding to a plurality of frames to be displayed continuously. The various elements in the projection system 100 (including the illumination optical device 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 such as a hard disk of the projection system 100, may be derived from a removable medium operably connected to the projection system 100, or may be derived from a combination of the above.

[0027] The first projection optics 107 and / or the second projection optics 111 may include filters to mitigate effects caused by internal components of the projection system 100. In some systems, the PLM 105 (described in more detail below) may include a cover glass and cause reflections, device switching may temporarily cause unwanted steering angles, and various components may cause scattering. To counteract this and reduce the minimum 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 contrast by reducing the minimum level from light near zero angle, which will correspond to elements such as cover glass reflections, travel conversion states, etc. This DC blocking area can be actively used to prevent certain light from reaching the screen. Additionally, the filter can mitigate modal noise from the light source 101 (such as a fiber-coupled laser) that is reflected by the cover glass and has energy at a small angle relative to most of the emitted light. An example of reducing cover glass noise is provided in PCT Patent Application No. PCT / US2020 / 013950, “Attenuating Wavefront Determination for Noise Reduction,” by Angelo P. Arrifano and Juan P. Pertierra, which is incorporated herein by reference. In some aspects of the disclosure, the filter prevents the undesired light from reaching the screen by diverting the light to a light collector located outside the active image area in response to control from the controller 114.

[0028] Although Figure 1 A generally linear optical path is illustrated, but in reality the optical path is often more complex. For example, in the projection system 100, the second light 104 from the illumination optics 103 is turned at an oblique angle to the PLM 105, and the fourth light 108 from the first projection optics 107 is turned at an oblique angle to the DLP 109. To ensure that the image on the screen 113 has acceptable clarity and contrast, the illumination optics 103 can be designed and / or controlled to ensure that the angle of incidence on the PLM 105 is correct while keeping the position of the second light 104 centered on the PLM 105. The PLM 105 and / or the first projection optics 107 can be designed and / or controlled to ensure that the angle of incidence on the DLP 109 is correct while keeping the position of the fourth light 108 centered on the DLP 109.

[0029] Digital Light Processor

[0030] In some embodiments, the DLP 109 is a digital micromirror device (DMD) composed of multiple mirrors for adjusting the incident angle of light (e.g., the fourth light 108). To illustrate the impact of the incident angle and the DMD mirrors, FIG. 2A to FIG. 2B An exemplary DMD 200 is shown in accordance with various aspects of the present disclosure. In particular, Figure 2A A plan view of the DMD 200 is shown, and Figure 2B The diagram shows Figure 2A 2-B. 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 a pixel of a final projected image and may be configured to tilt around a rotation axis 208 (which is shown for a specific subset of micromirrors 202) due to electrostatic or other types of actuation. Each micromirror 202 has a width 212 and is arranged with a gap of width 210 between the micromirrors. The micromirrors 202 may be coated with or formed of any highly reflective material such as aluminum or silver to specularly reflect light. The gaps between the micromirrors 202 may be absorptive so that input light entering the gaps is absorbed by the substrate 204.

[0031] Although Figure 2A Only some representative micromirrors 202 are explicitly shown, 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. Furthermore, in some examples, the micromirrors 202 may be rectangular and arranged in a rectangular array; may be hexagonal and arranged in a hexagonal array, etc. Furthermore, although Figure 2A The rotation axis 208 is illustrated extending in an oblique direction, but in some embodiments, the rotation axis 208 may extend vertically or horizontally.

[0032] like Figure 2B As can be seen in FIG. 1 , each micromirror 202 may be connected to a substrate 204 via a yoke 214 that is rotatably connected to the micromirror 202. The substrate 204 includes a plurality of electrodes 216. Figure 2B Only two electrodes 216 are visible per micromirror 202 in the cross-sectional view of FIG. 1 , but each micromirror 202 may actually include additional electrodes. Figure 2B200, but DMD 200 may also include a spacer layer, a support layer, a hinge member for controlling the height or orientation of micromirror 202, etc. Substrate 204 may include electronic circuits associated with DMD 200, such as complementary metal oxide semiconductor (CMOS) transistors, memory elements, etc.

[0033] Depending on the specific operation and control of the electrode 216, each micromirror 202 can be switched between an "on" position, an "off" position, and an unactuated or neutral position. If the micromirror 202 is in the on position, it is actuated to an angle of, for example, -12° (i.e., 12° counterclockwise relative to the neutral position) to mirror-reflect the input light 206 into an on-state light 218. If the micromirror 202 is in the off position, it is actuated to an angle of, for example, +12° (i.e., 12° clockwise relative to the neutral position) to mirror-reflect the input light 206 into an off-state light 220. The off-state light 220 can be directed toward a light collector that absorbs the off-state light 220. In some instances, the micromirror 202 can be unactuated and parallel to the substrate 204. In FIG. 2A to FIG. 2B The specific angles illustrated in and described herein are exemplary only and are not limiting. In some embodiments, the open position angle and the closed position angle may be between ±11 degrees and ±13 degrees, respectively (inclusive). In other embodiments, the open position angle and the closed position angle may be between ±10 degrees and ±18 degrees, respectively (inclusive).

[0034] Phase Optical Modulator

[0035] like Figure 1 As illustrated, the controller 114 also controls the PLM 105, which receives light from the light source 101. The PLM 105 imparts a spatially varying phase modulation to the light and redirects the modulated light toward the first projection optics 107. The PLM 105 can be a reflective type, in which the PLM 105 reflects incident light with a spatially varying phase; alternatively, the PLM 105 can be a transmissive type, in which the PLM 105 imparts a spatially varying phase to the light as the light passes through the PLM 105. In some aspects of the disclosure, the PLM 105 has a liquid crystal on silicon (LCOS) architecture. In other aspects of the disclosure, the PLM 105 has a micro-electromechanical system (MEMS) architecture.

[0036] Figure 3 An example of a PLM 105 is illustrated, which is implemented as a reflective LCOS PLM 300 and is shown in a partial cross-sectional view. Figure 3As shown, 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 a spacer 360. The silicon backplane 310 includes electronic circuits associated with the PLM 300, such as CMOS transistors, etc. The first electrode layer 320 includes an array of reflective elements 321 arranged in a transparent matrix 322. The reflective elements 321 can be formed of any highly optically reflective material such as aluminum or silver. The transparent matrix 322 can be formed of any highly optically transmissive material such as a transparent oxide. The second electrode layer 330 can be formed of any optically transparent conductive material such as an indium tin oxide (ITO) film. The second electrode layer 330 can be provided as a common electrode corresponding to the plurality of reflective elements 321 of the first electrode layer 320. In such a configuration, each of the plurality of reflective elements 321 will be coupled to the second electrode layer 330 via a corresponding electric field, thereby dividing the PLM 300 into an array of pixel elements. Therefore, each reflective element (or a subset) of the plurality of reflective elements 321 may be addressed via electronic circuitry disposed in the silicon backplate 310 , thereby modifying the state of the corresponding reflective element 321 .

[0037] 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 that exist in a phase between a solid state and a liquid state; in other words, the liquid crystals 341 exhibit a certain degree of directional order, rather than positional order. The direction in which the liquid crystals 341 tend to point is called a "director." The liquid crystal layer 340 modifies the incident light entering 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 a direction parallel to the director and the refractive index in a direction perpendicular to the director. Thus, the maximum optical path difference can be expressed as the birefringence multiplied by the thickness of the liquid crystal layer 240. The thickness is set by the spacer 260, which seals the PLM 300 and ensures a set distance between the cover glass 350 and the silicon backplane 310. The liquid crystals 341 generally orient themselves along the electric field lines between the first electrode layer 320 and the second electrode layer 330. As Figure 3 As shown, liquid crystal near the center of PLM 300 is oriented in this manner, while liquid crystal 241 near the periphery of PLM 300 is substantially unoriented due to the absence of electric field lines passing therethrough. By addressing individual ones of the plurality of reflective elements 321 via a phase drive signal, the orientation of liquid crystal 341 can be determined on a pixel-by-pixel basis.

[0038] Figure 4 Another example of a PLM 105 is illustrated, which is implemented as a DMD PLM 400 and is shown in a partial cross-sectional view. Figure 4As shown, the PLM 400 includes a back plate 410 and a plurality of controllable reflective elements as pixel elements, each of which includes a yoke 421, a reflector plate 422, and a pair of electrodes 430. Figure 4 Only two electrodes 430 are visible in the cross-sectional view of FIG, but each reflective element may actually include additional electrodes. Figure 4 Although not specifically shown in FIG. 4 , PLM 400 may further include spacer layers, support layers, hinge components for controlling the height or orientation of mirror plate 422, etc. Backplane 410 includes electronic circuits associated with PLM 400, such as CMOS transistors, memory arrays, etc.

[0039] The yoke 421 may be formed of or include a conductive material to allow 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 value of the voltage on the electrode 430 and the voltage on the mirror plate 422 (e.g., the bias voltage), there is a potential difference between the mirror plate 422 and the electrode 430, which generates an electrostatic force acting on the mirror plate 422. The yoke 421 is configured to allow the mirror plate 422 to move vertically in response to the electrostatic force. The equilibrium position of the mirror plate 422 that occurs when the electrostatic force and the spring-like force of the yoke 421 are equal determines the optical path length of the light reflected from the upper surface of the mirror plate 422. Therefore, each of the controllable reflective elements in the plurality of controllable reflective elements is controlled to provide a plurality of (three as illustrated) discrete heights and thus provide a plurality of discrete phase configurations or phase states. As illustrated, each phase state has a flat curve. In some aspects of the disclosure, electrodes 430 may be provided with different voltages from one another in order to impart a tilt to mirror plate 422. Such a tilt may be used with light collectors of the type described above.

[0040] For example, the PLM 400 may be capable of a high switching speed, such that the PLM 400 switches from one phase state in, for example, the order of tens of μs. To provide a complete phase control cycle, 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. Therefore, the height range between the highest point and the lowest point should be approximately equal to λ / 2.

[0041] In some embodiments, the PLM 105 creates fixed diffraction orders where the mirror plate 422 produces multiple "copies" of the light impinging thereon. The PLM 105 steers the light within the range of each diffraction order, thereby producing multiple "copies" of the image at the reconstruction plane. The image steered by the PLM 105 can be formed on the image reconstruction plane at a distance where the diffraction orders are separated and do not overlap. In some embodiments, the image reconstruction plane is closer to the PLM 105 to reduce blurring of the reconstructed image. A Fourier filter is implemented with the PLM 105 to remove overlap of the diffraction orders at the image reconstruction plane. In some embodiments, the diffraction patterns constructively interfere with each other to form the reconstructed image. Accordingly, if a portion of the light steered by the PLM 105 is blocked, the reconstructed image is blurred compared to a reconstructed image that includes all of the light from the PLM 105.

[0042] Optical Architecture

[0043] One exemplary embodiment of the present disclosure provides an optical system having a first light steering pre-modulator (eg, a PLM) followed by a second modulator (eg, a DLP). Figure 5 An exemplary optical state of a partial optical system 500 according to the present disclosure is illustrated. The partial optical system 500 may be, at least in part, an example of the projection system 100.

[0044] In particular, Figure 5 A light source 501, a first light 502, an illumination optics 503, a second light 504, a first modulator 505, a third light 506, an illumination relay optics 507, a fourth light 508, a second modulator 509, a fifth light 510, a second projection optics 511, a sixth light 512 and an optical output 513 are illustrated. Figure 5 The various components shown in the figure can be used with Figure 1 The illustrated elements (or portions of the elements) correspond. In some embodiments, the first modulator 505 is a PLM device and the second modulator 509 is a DLP device. In other embodiments, the first modulator 505 is a DLP device and the second modulator 509 is a PLM device. In some embodiments, the first modulator 505 is within a prism (such as a prism that converts light in an RGB color domain into white light) for modulation. In some examples, the second modulator 509 is within a prism 521 (such as a prism that converts light in an RGB color domain into white light).

[0045] exist Figure 5In the illustrated embodiment, the illumination optics 503 includes a first diffuser 514, a first lens 515, and a second lens 516. The first diffuser 514 can change the first light 502 and create a desired point spread function (PSF) for the second light 504 received by the first modulator 505. In some embodiments, 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 spinning. In other examples, the first diffuser 514 is stationary. In some embodiments, the first diffuser 514 can blur the image projected by the light source 501, thereby avoiding the need for precise alignment requirements.

[0046] Although shown as including two lenses, the illumination optical device 503 can be composed of any number of lenses to direct the first light 502 to the first modulator 505 at a predetermined illumination angle θ. In addition, although each individual lens is illustrated separately, the individual lenses can be cemented to each other. Additionally, each lens group can be composed of any type of lens, such as a concave lens, a collimating lens, a negative meniscus lens, and a positive meniscus lens.

[0047] exist Figure 5 In the illustrated embodiment, the illumination relay optics 507 (e.g., imaging relay optics) includes a third lens 518, a first filter 519, and a fourth lens 520. In other embodiments, the illumination relay optics 507 may not include the first filter 519. The first filter 519 may include an aperture configured to allow the third light 506 of a predetermined diffraction order or a predetermined illumination angle to pass through. For example, the first filter 519 may include a "Fourier section" or a "Fourier lens assembly", which refers to an optical system that performs a spatial Fourier transform on the modulated light (e.g., light from the first modulator 505) by focusing the modulated light onto a Fourier plane. The spatial Fourier transform applied by the Fourier section converts the propagation angle of each diffraction order of the modulated light into a corresponding spatial position on the Fourier plane. The Fourier section is thereby able to select the desired diffraction order and reject the undesired diffraction order by performing spatial filtering at the Fourier plane. For example, the Fourier portion can be configured to allow projection light at an angle of 12° to pass through. The spatial Fourier transform of the modulated light at the Fourier plane is equivalent to the Fraunhofer diffraction pattern of the modulated light. In some embodiments, the first optical filter 519 blocks light components that increase the black level, thereby reducing the black level and improving the effective contrast of the first modulator 505. In some embodiments, the first optical filter 519 is optically located between the first modulator 505 and the third lens 518 to improve the characteristics of the light modulated by the first modulator 505.

[0048] Although shown as including two lenses, the illumination relay optics 507 may be comprised of any number of lenses to direct the fourth light 508 at the second predetermined illumination angle. Guided to the second modulator 509. In addition, although each individual lens is illustrated separately, the individual lenses can be glued to each other. In some examples, the third lens 518 and the fourth lens 520 can be composed of several lenses forming a lens group. Additionally, each lens or lens group can be composed of any type of lens, such as a concave lens, a negative meniscus lens, and a positive meniscus lens.

[0049] exist Figure 5 In some embodiments, the second projection optical device 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 embodiments, the second projection optical device 511 may not include the second filter 525. The second filter 525 can be functionally similar to the first filter 519 (e.g., including a "Fourier part"). In some embodiments, the second filter 525 is configured to improve the black level of the second modulator 509. In some embodiments, the optical system 500 includes a window actuator 522, which is optically located between the second modulator 509 and the second projection optical device 511. The window actuator 522 is configured to increase the resolution of the image (e.g., the fifth light 510) reflected by the second modulator 509. For example, the window actuator 522 may upgrade the 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, and so on.

[0050] In some embodiments, the optical system 500 includes a second diffuser 517. The second diffuser 517 can define a plane on which the image from the first modulator 505 is reconstructed (e.g., a reconstructed image plane). In some embodiments, the reconstructed image plane is parallel to the first modulator 505. After image reconstruction, the second diffuser 517 can also add angular diversity to the third light 506, thereby reducing the impact of dust and other obstructions within the optical system 500. In some embodiments, 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 spinning. In other examples, the second diffuser 517 is stationary.

[0051] In other embodiments, the reconstructed image plane is separated from the second diffuser 517. For example, the reconstructed image plane can be located optically upstream or optically downstream of the second diffuser 517. In embodiments where the optical system 500 does not include the second diffuser 517, the reconstructed image plane can 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. Additionally, in some embodiments, the reconstructed image plane can be angularly offset from the first modulator 505. In such embodiments, the illumination relay optics 507 can be configured to control the third light 506 so that the reconstructed image contacts the second modulator 509 at a desired angle. For example, the illumination relay optics 507 is tilted so that the image plane between the second diffuser 517 and the second modulator 509 is aligned with the second illumination angle. or 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 embodiments, a glass sheet or an additional lens (such as a tilted or decentered lens element or a glass prism element) is used to tilt the reconstructed image plane so that the reconstructed image contacts the second modulator 509 at a desired angle.

[0052] In some embodiments, the image reconstruction plane is optically before the first modulator 505. For example, the image reconstruction plane can be located at the first diffuser 514, or optically located between the first modulator 505 and the first diffuser 514. In such embodiments, the image reconstruction plane can be virtual, such that it is visible downstream from the first modulator 505.

[0053] The angle between the reconstructed image formed on the reconstructed 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 relative to the reconstructed image plane. To account for this tilt in the reconstructed image, in some embodiments, the first illumination angle θ is selected to meet the Scheimpflug criterion of the second modulator 509. As previously described, when the second modulator 509 is a DMD, the micromirror 202 is tilted to approximately 12°. In this embodiment, the first illumination angle θ is selected to be approximately 24°. In an embodiment where the second modulator 509 is a DLP, the second modulator has a reflector that is tilted diagonally (i.e., 45° azimuth tilt). In this case, the first illumination angle θ at the first modulator 505 is also selected to be 45°. By selecting the first illumination angle θ to meet the Scheimpflug criterion, the reconstructed image is fully focused on the second modulator 509. In other embodiments, the second illumination angle is selected to be approximately 24°. In the case where the first modulator 505 and the second modulator 509 comprise prisms, the respective illumination angles of the first modulator and the second modulator may be selected taking into account the geometry of the prisms.

[0054] In some embodiments, the distortion of the reconstructed image causes the image on the second modulator 509 to have a trapezoidal shape. This distortion prevents the effective filling of the second modulator 509 because the trapezoidal shape cannot fill the rectangular shape of the second modulator 509. Accordingly, the first illumination angle θ can be selected so that the reconstructed image provided by the first modulator 505 is approximately rectangular on the second modulator 509, thereby improving optical efficiency. In some embodiments, the reconstructed image provided by the first modulator 505 is distorted so that the image is approximately rectangular on the second modulator 509.

[0055] 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 construction of the optical system 500. In some embodiments, the positions of the light source 501, the illumination optics 503, and the illumination relay optics 507 can be set or adjusted using corresponding tracks and actuators controlled by the controller 114 to change the first illumination angle θ. In some embodiments, the reflective properties 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.

[0056] In some embodiments, optical system 500 represents only a single color channel of projection system 100. Accordingly, each color channel in projection system 100 can have its own optical system configured similarly to optical system 500, each with its own corresponding PLM 105 and DLP 109. Each color channel can be combined after their respective optical outputs 513 and then projected onto screen 113. Optical output 513 can be a 3-channel prism, such as found in U.S. Pat. No. 10,197,902, "High Contrast Discrete Input Prism for Image Projectors," which is incorporated herein by reference in its entirety.

[0057] The above projection system may provide an optical configuration that utilizes a reconstructed image plane of an image reflected by a first modulator to improve the efficiency of a second modulator.

[0058] Systems, methods, and devices according to the present disclosure may adopt any one or more of the following configurations.

[0059] (1) A beam steering projection system, the beam steering projection system comprising: a light source, the light source being configured to emit light in response to an image signal, wherein the image signal comprises image data; a phase light modulator, the phase light modulator being configured to receive light from the light source and to apply spatially varying phase modulation to the light, thereby steering the light at an illumination angle and generating a first steering light; and a spatial light modulator, the spatial light modulator being configured to receive the first steering light, apply spatially varying amplitude modulation to the light, thereby steering the light toward a projection optical system and generating a second steering 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.

[0060] (2) The beam steering projection system of (1), wherein the illumination angle satisfies the Scheimpflug criterion for the spatial light modulator.

[0061] (3) According to any one of (1) to (2), the beam steering projection system further includes a diffuser optically disposed between the phase light modulator and the spatial light modulator.

[0062] (4) The beam steering projection system of (3), wherein the secondary image is constructed at the diffuser.

[0063] (5) According to any one of (1) to (4), the beam steering projection system also includes a filter optically arranged between the phase light modulator and the spatial light modulator, wherein the filter is configured to increase the effective contrast of the first steered light.

[0064] (6) According to any one of (1) to (5), the beam steering projection system also includes a diffuser optically arranged between the light source and the phase light modulator, and the diffuser is configured to create a preconfigured point spread function of the light.

[0065] (7) According to any one of (1) to (6), the beam steering projection system also includes a filter optically arranged after the spatial light modulator, wherein the filter is configured to reduce the black level of the second steering light.

[0066] (8) The beam steering projection system according to any one of (1) to (7), wherein the spatial light modulator is disposed within a prism.

[0067] (9) A beam steering projection system, comprising: a light source, configured to emit light; a first modulator, configured to receive light from the light source and apply spatially varying phase modulation to the light, thereby steering the light at a first illumination angle and generating first steering light; an imaging relay optical device, configured to receive the first steering light and generate second steering light at a second illumination angle; and a second modulator, configured to receive the second steering light, apply spatially varying amplitude modulation to the light, thereby steering the light toward a projection optical system and generating third steering light, wherein a plane of a secondary image constructed after the first modulator and before the second modulator is parallel to the first modulator.

[0068] (10) The beam steering projection system of (9), wherein the first modulator and the second modulator are digital micromirror devices.

[0069] (11) According to any one of (9) to (10), the beam steering projection system also includes a first diffuser, which is optically arranged between the first modulator and the second modulator.

[0070] (12) According to any one of (9) to (11), the beam steering projection system also includes a filter optically arranged between the first modulator and the second modulator, wherein the filter is configured to increase the effective contrast of the first steered light.

[0071] (13) The beam steering projection system of (12), wherein the filter is optically disposed between the first modulator and the imaging relay optical device.

[0072] (14) According to any one of (9) to (13), the beam steering projection system also includes a diffuser optically arranged between the light source and the first modulator, and the diffuser is configured to create a preconfigured point spread function of the light.

[0073] (15) According to any one of (9) to (14), the beam steering projection system also includes a filter optically arranged after the second modulator, wherein the filter is configured to reduce the black level of the third steering light.

[0074] (16) According to any one of (9) to (15), the beam steering projection system also includes a window actuator optically arranged between the second modulator and the projection optical system, and the window actuator is configured to increase the resolution of the image defined by the third steering light.

[0075] (17) According to any one of (9) to (16), the beam steering projection system also includes a diffuser optically arranged between the first modulator and the second modulator, wherein the secondary image is constructed at the diffuser.

[0076] (18) A method for a beam steering projection system, the beam steering projection system comprising: a light source, the light source being configured to emit light; a phase light modulator, the phase light modulator being configured to receive light from the light source and to apply spatially varying phase modulation to the light, thereby steering the light at an illumination angle and generating a first steering light; and a spatial light modulator, the spatial light modulator being configured to receive the first steering light and to apply spatially varying amplitude modulation to the light, thereby steering the light toward a projection optical system, the method comprising: receiving light from the light source using the phase light modulator, steering the light at the illumination angle to generate the first steering light using the phase light modulator, constructing a reconstructed image on a reconstructed image plane using the first steering light, and receiving the first steering light using the spatial light modulator.

[0077] (19) The method according to (18), wherein the beam steering projection system also includes a filter optically arranged between the phase light modulator and the spatial light modulator, and wherein the method also includes: using the filter to increase the effective contrast of the first steering light.

[0078] (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).

[0079] (21) A beam steering projection system according to (12) or (13), or any one of (14) to (17) when dependent on (12) or (13), wherein the filter is configured to block light components that increase the black level.

[0080] (22) A beam steering projection system according to any one of (21), (12), (13), or (14) to (17) when subject to (12) or (13), wherein the filter is configured to block one or more diffraction orders of the first steered light.

[0081] With respect to the processes, systems, methods, heuristics, etc. described herein, it should be understood that although the steps of these processes, etc. have been described as being performed in a particular ordered order, these processes can be practiced with the described steps performed in an order different from that described herein. It should further be understood that certain steps can be performed simultaneously, other steps can be added, or certain steps described herein can be omitted. In other words, the process descriptions herein are provided for the purpose of illustrating certain embodiments and should in no way be construed as limiting the claims.

[0082] Accordingly, it should be understood that the above description is intended to be illustrative rather than restrictive. By reading the above description, many embodiments and applications other than the examples provided will be apparent. The scope should not be determined with reference to the above description, but should be determined with reference to the full range of equivalents to which the appended claims and these claims are eligible for consideration. It is expected and desired that the technology discussed herein will develop in the future, and the disclosed systems and methods will be incorporated into such future embodiments. In a word, it should be understood that the present application is capable of modification and change.

[0083] All terms used in the claims are intended to be given their broadest reasonable interpretations and ordinary meanings as understood by those skilled in the art described herein, unless an explicit indication to the contrary appears herein. In particular, use of singular articles such as "a," "an," "the," and "said" should be understood to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.

[0084] The abstract of the present disclosure is provided to allow the reader to quickly determine the nature of the technical disclosure. This abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the aforementioned detailed description, it can be seen that various features are combined together into various embodiments for the purpose of connecting the present disclosure as a whole. The method of the present disclosure should not be interpreted as reflecting the intention that the claimed embodiments incorporate more features than those explicitly recited in each claim. On the contrary, as reflected in the attached claims, the inventive subject matter lies in less than all the features of a single disclosed embodiment. Therefore, the attached claims are hereby incorporated into the detailed description, and each claim stands alone as a separately claimed subject matter.

Claims

1. A beam steering projection system, the beam steering projection system comprising: a light source configured to emit light in response to an image signal, wherein the image signal includes image data; a phase light modulator configured to receive light from the light source and apply spatially varying phase modulation to the light, thereby turning the light at an illumination angle and generating first turned light; and a spatial light modulator configured to receive the first redirected light, apply spatially varying amplitude modulation to the light, redirect the light toward the projection optical system and generate second redirected 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.

2. The beam steering projection system of 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 at the diffuser.

4. The beam steering projection system according to any one of claims 1 to 3, further comprising a filter optically arranged between the phase light modulator and the spatial light modulator, wherein: The filter is configured to increase the effective contrast of the first turned light and block one or more diffraction orders of the first turned light.

5. The beam steering projection system according to any one of claims 1 to claim 4, further comprising a diffuser optically disposed between the light source and the phase light modulator, the diffuser being configured to create 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 arranged after the spatial light modulator, wherein: The filter is configured to reduce a black level of the second redirected light.

7. A beam steering projection system, comprising: a light source configured to emit light; a first modulator configured to receive light from the light source and apply spatially varying phase modulation to the light, thereby steering the light at a first illumination angle and generating first steered light; imaging relay optics configured to receive the first turned light and produce second turned light at a second illumination angle; as well as a second modulator, the second modulator being configured to receive the second redirected light, apply spatially varying amplitude modulation to the light, redirect the light toward the projection optical system and generate third redirected light, Wherein, a plane of the secondary image constructed after the first modulator and before the second modulator is parallel to the first modulator.

8. The beam steering projection system of 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 any one of claims 7 to 8, further comprising a filter optically arranged between the first modulator and the second modulator, wherein: The filter is configured to increase the effective contrast of the first redirected 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 to block one or more diffraction orders of the first turned 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 optics.

12. The beam steering projection system of 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 create 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, wherein: The secondary image is constructed at the diffuser.

14. 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 light from the light source and apply spatially varying phase modulation to the light, thereby steering the light at an illumination angle and generating first steered light; and a spatial light modulator configured to receive the first redirected light and apply spatially varying amplitude modulation to the light so as to redirect the light toward a projection optical system, the method comprising: receiving light from the light source using the phase light modulator, using the phase light modulator to redirect the light at the illumination angle to generate the first redirected light, constructing a reconstructed image on a reconstructed image plane using the first deflected light, and The first redirected light is received by using the spatial light modulator.

15. The method according to claim 14, wherein: The beam steering projection system further comprises an optical filter optically disposed between the phase light modulator and the spatial light modulator, and wherein the method further comprises: using the filter to increase the effective contrast of the first redirected light, and The filter is used to block one or more diffraction orders of the first redirected light.

16. A non-transitory computer readable medium storing instructions which, when executed by a processor of a beam steering projection system, cause the beam steering projection system to perform operations including the method of any one of claims 14 to 15.

Images