Projection system and method with adjustable angle illumination

Abstract

A projection system and a calibration method thereof, comprising: a light source configured to emit light in response to image data; an illumination optical system configured to guide the light, the illumination optical system comprising a first reflector and a second reflector; a digital micromirror device (DMD) comprising a plurality of micromirrors, each configured to reflect the guided light as on-state light to a filter, or to reflect the guided light as off-state light to a light collector; determining a deviation between an actual orientation angle of the DMD and an expected orientation angle; calculating a first angular adjustment amount corresponding to the first reflector and a second angular adjustment amount corresponding to the second reflector; and actuating the first reflector according to the first amount and actuating the second reflector according to the second amount.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 014,239, filed on April 23, 2020, and European Patent Application No. 20171002.7, filed on April 23, 2020, which are incorporated herein by reference. Technical Field

[0003] The present application relates generally to projection systems and methods for driving projection systems. Background Art

[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, and spatial light modulators (SLMs). The contrast ratio of a projector represents the projector's brightest output relative to the projector's darkest output. The contrast ratio is a quantifiable measure of contrast and is defined as the ratio of the brightness of the projector's brightest output to the brightness of the projector's darkest output. This definition of contrast ratio is also known as the "static" or "natural" contrast ratio.

[0005] Some projection systems are based on an SLM that implements spatial amplitude modulation. In such systems, a light source provides a light field that represents the brightest level that can be reproduced in the image, and the light is attenuated or discarded to create the desired scene level. Some high-contrast examples of projection systems based on this structure use a Fourier stop and semi-collimated illumination system in the projection optics to improve contrast. In this structure, the illumination angle at the SLM has a significant impact on the projected image, including but not limited to its contrast and clarity. Summary of the Invention

[0006] Various aspects of the present disclosure relate to devices, systems, and methods for projection displays for high contrast projection architectures.

[0007] In an exemplary aspect of the present disclosure, a projection system is provided, comprising: a light source configured to emit light in response to image data; an illumination optical system configured to guide the light, the illumination optical system comprising a first reflector and a second reflector; a digital micromirror device comprising a plurality of micromirrors, wherein each micromirror is configured to reflect the guided light as on-state light to a filter when the lens is in an on position, and to reflect the guided light as off-state light to a light collector when the lens is in a closed position; and a controller configured to: determine a deviation between an actual orientation angle of the digital micromirror device and an expected orientation angle of the digital micromirror device, calculate a first angular adjustment amount corresponding to the first reflector and a second angular adjustment amount corresponding to the second reflector, and actuate the first reflector according to the first amount and actuate the second reflector according to the second amount, so as to maintain a position and a focus of the guided light on the digital micromirror device and cause the on-state light to be incident within a predetermined distance from a center of the filter.

[0008] In another exemplary aspect of the present disclosure, a method for calibrating a projection system is provided, the projection system including a light source configured to emit light in response to image data; an illumination optical system configured to guide the light, the illumination optical system including a first reflector and a second reflector; and a digital micromirror device including a plurality of micromirrors, the plurality of micromirrors being respectively configured to reflect the guided light as on-state light to a filter when the lens is in an on position, and to reflect the guided light as off-state light to a light collector when the lens is in a closed position. The method includes: determining a deviation between an actual orientation angle of the digital micromirror device and an expected orientation angle of the digital micromirror device, calculating a first angular adjustment amount corresponding to the first reflector and a second angular adjustment amount corresponding to the second reflector, and actuating the first reflector according to the first amount and actuating the second reflector according to the second amount, so as to maintain a position and a focus of the guided light on the digital micromirror device and make the on-state light incident within a predetermined distance from a center of the filter.

[0009] In another exemplary aspect of the present disclosure, a non-transitory computer-readable medium storing instructions is provided that, when executed by a processor of a projection device, causes the projection device to perform operations. The projection device includes a light source configured to emit light in response to image data; an illumination optical system configured to guide the light, the illumination optical system including a first reflector and a second reflector; and a digital micromirror device (DMD) including a plurality of micromirrors, each configured to reflect the guided light as on-state light toward an optical filter when the lens is in an open position, and to reflect the guided light as off-state light toward a light collector when the lens is in a closed position. The operations include determining a deviation between an actual orientation angle of the DMD and an expected orientation angle of the DMD, calculating a first angular adjustment amount corresponding to the first reflector and a second angular adjustment amount corresponding to the second reflector, and actuating the first reflector according to the first amount and actuating the second reflector according to the second amount, thereby maintaining a position and a focus of the guided light on the DMD and causing the on-state light to be incident within a predetermined distance from a center of the optical filter.

[0010] Thus, various aspects of the present disclosure provide for the display of images with high dynamic range and high resolution, and achieve 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 A block diagram illustrating an exemplary projection system according to various aspects of the present disclosure is shown;

[0013] Figures 2A-2B shows diagrams of exemplary spatial light modulators useful in various aspects of the present disclosure;

[0014] Figures 3A-3B shows exemplary optical states in an exemplary projection system according to various aspects of the present disclosure;

[0015] Figure 4 Shown Figures 3A-3B An exemplary alignment method in an exemplary optical system;

[0016] Figures 5A-5B Shown Figures 3A-3B exemplary relationships between mirror angles in an exemplary optical system;

[0017] Figure 6 illustrates exemplary optical states in another exemplary projection system according to various aspects of the present disclosure;

[0018] Figure 7 Shown for Figure 6 an exemplary linkage of an exemplary optical system;

[0019] Figure 8 Shown for Figure 6 Another exemplary linkage of the exemplary optical system;

[0020] Figures 9A-9B Shown for Figure 6 an exemplary optical state of another exemplary linkage of an exemplary optical system;

[0021] Figure 10 Shown Figure 6 exemplary embodiments of exemplary optical systems; and

[0022] Figure 11 Shown Figure 6 An exemplary alignment method in an exemplary optical system. DETAILED DESCRIPTION

[0023] The present disclosure and its aspects may be embodied 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 disclosure in any way.

[0024] In the following description, many details are set forth, such as optical device configuration, timing, operation, etc., in order to provide an understanding of one or more aspects of the present disclosure. It will be apparent to those skilled in the art that these specific details are merely exemplary and are not intended to limit the scope of the present application.

[0025] Furthermore, while the present disclosure primarily focuses on examples of various circuits used in digital projection systems, it should be understood that this is merely one example of implementation. It should also be understood that the disclosed systems and methods can be used in any device that requires projecting light; for example, cinema-grade, consumer-grade, and other commercial projection systems, head-up displays, virtual reality displays, and the like.

[0026] projection system

[0027] The optics of an SLM-based projection system can be roughly divided into two parts: optics located on the illumination side (i.e., optically upstream of the SLM) and optics located on the projection side (i.e., optically downstream of the SLM). The SLM itself includes a plurality of modulating elements arranged in, for example, a two-dimensional array. Each modulating element receives light from the illumination optics and transmits the light to the projection optics. In some examples, the SLM can be implemented as a digital micromirror device (DMD); this will be discussed in more detail below. However, in general, a DMD includes a two-dimensional array of reflective elements (micromirrors or simply "mirrors") that selectively reflect light toward the projection optical system or discard light based on the position of each reflective element.

[0028] As described above, high-contrast projection systems that use a semi-collimated illumination system and a Fourier stop in the projection optics can be significantly affected by variations in the angle of incident light on the DMD. To prevent degradation of the projected image, the projection system can maintain the position and focus of the output of the illumination optics (e.g., light output from an integrator rod or other uniformity correction device and subsequently reflected by one or more reflective elements) on the DMD, while keeping the reflected beam centered within the input of the projection optics (e.g., the filter aperture). However, the exact position of the first and second angles of the DMD mirrors can be affected by manufacturing or other tolerances, resulting in some variation in the actual first and second angles. To compensate for variations in the DMD mirror angles between different physical DMDs and ensure that the beam is properly centered, the angle of light emitted (e.g., reflected) from the DMD can be controlled. This control should be robust to variations in the first and second angles of the DMD mirrors. Robustness against angular variations can be provided by implementing adjustment of the angle of incidence of the light beam on the DMD so that, when reflected by the DMD mirrors, the exiting beam is always at (or substantially at) the nominal design exit angle to the aperture. Furthermore, because each color channel in a color projection system may have different angular requirements, it is desirable to provide adjustments for each color.

[0029] The structure of such a high contrast projection system may provide special constraints in addition to the adjustment and maintenance of the proper illumination angle. For example, the projection system may utilize a prism that recombines the three colors and / or a folding mirror before the prism to reduce the size of the optics and the projector itself. In addition, because the illumination optics focus the aperture onto the DMD, the optics may be constrained to maintain a constant distance between the aperture and the DMD. Furthermore, as described above, the image of the aperture must be centered on the DMD. Here, an example of a projection system is described that is capable of adjusting the input angle to the DMD without changing the focus or position of the integrating rod (or other uniformity correction device) at the DMD.

[0030] Figure 1An exemplary high contrast projection system 100 according to various aspects of the present disclosure is shown. Specifically, Figure 1 A projection system 100 is shown, which includes 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), which is configured to receive the first light 102 and redirect or modify it to generate a second light 104; a DMD 105, which is configured to receive the second light 104 and selectively redirect and / or modulate it into a third light 106; a filter 107, which is configured to filter the third light 106 to produce a fourth light 108; and a projection optics 109, which is configured to receive the fourth light 108 and project it as a fifth light 110 onto a screen 111.

[0031] In actual implementation, the projection system 100 may include fewer optical components, or may include additional optical components, such as mirrors, lenses, waveguides, optical fibers, beam splitters, diffusers, etc. In addition to the screen 111, Figure 1 The components shown can be integrated into a housing to provide a projection device. Such a projection device can include additional components such as memory, input / output ports, communication circuitry, a power supply, etc.

[0032] The light source 101 can be, for example, a laser light source, an LED, or the like. Generally, the light source 101 is any light emitter that emits coherent light. In some aspects of the present disclosure, the light source 101 can include a plurality of separate light emitters, each corresponding to a different wavelength or wavelength band. The light source 101 emits light in response to an image signal provided by a controller 112; for example, one or more processors, such as a central processing unit (CPU) of the projection system 100. The image signal includes image data corresponding to a plurality of frames to be displayed continuously. Various elements in the projection system 100, including the illumination optical device 103 and / or the DMD 105, can be controlled by the controller 112. The image signal can originate from an external source in a streaming or cloud-based manner, can originate from an internal memory of the projection system 100, such as a hard disk, can originate from a removable medium operably connected to the projection system 100, or a combination thereof.

[0033] although Figure 1 A generally linear optical path is shown, but in practice the optical path is typically more complex. For example, in projection system 100, second light 104 from illumination optics 103 is directed to DMD chip 105 (or chips) at a fixed angle determined by the steering angle of the DMD mirrors.

[0034] To illustrate the effect of incident angle and DMD mirrors, Figures 2A-2B An exemplary DMD 200 is shown in accordance with various aspects of the present disclosure. Figure 2Ashows a plan view of the DMD 200, and Figure 2B A partial cross-sectional view of a DMD 200 is shown. The DMD 200 includes a plurality of square micromirrors 202 arranged in a two-dimensional rectangular array on a substrate 204. In some examples, the DMD 200 may be a digital light processor (DLP) from Texas Instruments. Each micromirror 202 may correspond to a pixel of the final projected image and may be configured to tilt relative to a rotation axis 208 shown for a particular subset of the micromirrors 202 by electrostatic or other actuation. Each micromirror 202 has a width 212 and is arranged with a spacing of width 210 therebetween. The micromirrors 202 may be formed of or coated with any highly reflective material, such as aluminum or silver, to specularly reflect light. The spacing between the micromirrors 202 may be absorptive so that input light entering the spacing is absorbed by the substrate 204.

[0035] Although Figure 2A Only a few representative micromirrors 202 are 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), and so on. Furthermore, in some examples, the micromirrors 202 may be rectangular and arranged in a rectangular array; hexagonal and arranged in a hexagonal array; and so on. Furthermore, although Figure 2A The rotation axis 208 is shown extending in an oblique direction, but in some embodiments, the rotation axis 208 may extend vertically or horizontally.

[0036] like Figure 2B As shown, each micromirror 202 can be connected to a substrate 204 via a yoke 214, which is rotatably connected to the micromirror 202. The substrate 204 includes a plurality of electrodes 216. Figure 2B Only two electrodes 216 are visible in each micromirror 202 in the cross-sectional view of FIG, but each micromirror 202 may actually include additional electrodes. Figure 2B Although not specifically shown, the DMD 200 may further include a spacer layer, a support layer, a hinge member for controlling the height or orientation of the micromirror 202, etc. The substrate 204 may include electronic circuits associated with the DMD 200, such as CMOS transistors, memory elements, etc.

[0037] Depending on the specific operation and control of the electrodes 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., rotated 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., rotated 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 may be directed to a light collector (light dump) that absorbs the off-state light 220. In some cases, the micromirror 202 may be unactuated and parallel to the substrate 204. Figures 2A-2B The specific angles shown in the figure are merely exemplary and non-limiting. In some embodiments, the open position and closed position angles can be between ±12 degrees and ±13 degrees (inclusive).

[0038] exist Figure 1 In the context of FIG, the DMD mirrors use a tilt angle of 12° to reflect or discard light, and the second light 104 is directed at a fixed angle of 24° to the DMD chip 105. When the single mirror is tilted at a first predetermined angle (e.g., -12°), the mirror is considered to be in the on state and redirects the light to the filter 107 and the projection optics 109. When the single mirror is tilted at a second predetermined angle (e.g., +12°), the mirror is considered to be in the off state and redirects the light to a light collector located outside the active image area.

[0039] To ensure that the image on screen 111 has acceptable clarity and contrast, the illumination optics can be designed and / or controlled to ensure that the angle of incidence on DMD 105 is correct, aperture focus is maintained, and aperture position is maintained, regardless of the presence of prisms and fold mirrors in projection system 100.

[0040] Dual mirror alignment control system

[0041] In an exemplary embodiment of the present disclosure, the above can be achieved by using two mirrors placed in series. Figures 3A-3B An exemplary optical state of a portion of an optical system 300 according to the present invention is shown.

[0042] In particular, Figures 3A-3BAn integrator rod 301, a first light 302, an illumination lens system 303 (which may include one or more individual lenses), a second light 304, a first reflector 305, a third light 306, a second reflector 307, a fourth light 308, a DMD 309, a fifth light 310, an aperture 311, and a sixth light 312 are shown. The first reflector 305 and the second reflector 307 are both configured for angular adjustment. Because the first reflector 305 is located optically upstream (and therefore further away from the DMD) than the second reflector 307, the position of the third light 306 on the second reflector 307 moves when the first reflector 305 changes its angle. In this way, the first reflector 305 is configured to primarily provide translation (i.e., an effective translation function), while the second reflector 307 is configured to primarily provide angular adjustment. For purposes of explanation, Figures 3A-3B The portion of optical system 300 in FIG. 3 is shown in an orientation where first light 302 propagates generally horizontally. Figures 3A-3B The various elements shown in FIG. Figure 1 Various elements (or parts of various elements) shown in FIG.

[0043] In some examples, integrator rod 301 may be a component of light source 101 that receives light from the light-emitting elements of light source 101 and outputs light such that first light 302 corresponds to first light 102. In other examples, integrator rod 301 may be a component of illumination optics 103 such that integrator rod 301 receives first light 102 and integrates it to form first light 302. In some examples, illumination lens system 303, first reflector 305, and second reflector 307 are components of illumination optics 103 such that fourth light 308 corresponds to second light 104. First reflector 305 and / or second reflector 307 may be formed of or coated with any highly reflective material, such as aluminum or silver, to specularly reflect light.

[0044] DMD 309 may correspond to DMD 105. For ease of explanation, DMD 309 is illustrated as a flat surface; however, in reality, DMD 309 includes multiple individual reflective elements that may or may not be oriented along the same plane. Thus, DMD 309 may have a configuration such as Figures 2A-2B The structure shown is configured to selectively reflect and direct fourth light 308 (i.e., second light 104) depending on whether the various reflective components of DMD 309 are in an on position, a closed position, or a neutral position. Thus, fifth light 310 can correspond to third light 106. In some examples, aperture 311 can be a component of filter 107, thereby providing filtered illumination to the projection optics. Figures 3A-3BIn order to provide a suitable contrast ratio and image clarity, the fifth light 310 should be centered on the aperture 311.

[0045] exist Figure 3A In the illustrated state, the surface of DMD 309 is oriented at an angle of 12.5° (measured from vertical). To ensure that fifth light 310 is centered on aperture 311, first mirror 305 and second mirror 307 are each oriented at an angle of 45°. First light 302 propagates from integrator rod 301 along the horizontal optical axis to illumination lens system 303. In practice, first light 302 expands as it propagates, oriented toward a non-zero solid angle at the surface of illumination lens system 303. Illumination lens system 303 is configured to image first light 302 onto DMD 309 such that second light 304 is focused at a virtual point that is the same optical distance from the exit of illumination lens system 303 as DMD 309. In other words, the focal point of illumination lens system 303 is located at a distance substantially equal to the sum of the optical path lengths of second light 304, third light 306, and fourth light 308.

[0046] Second light 304 is specularly reflected by first mirror 305, causing third light 306 to propagate vertically toward second mirror 307. Third light 306 is specularly reflected by second mirror 307, causing fourth light 308 to propagate horizontally toward DMD 309, where it is reflected toward the center of aperture 311 as fifth light 310.

[0047] However, in practice, any deviation in the orientation angle of the DMD 309 will cause a shift in the incident point of the fifth light 310 on the aperture 311. This shift can be offset by adjusting the first reflector 305 and the second reflector 307. Figure 3B Such a countermeasure is shown.

[0048] exist Figure 3B In the state shown, the surface of DMD 309 is oriented at an angle of 10.5° (measured from vertical), which is consistent with Figure 3A The states shown differ by 2°. This angular difference is provided for ease of explanation in the visualization; in actual implementation, manufacturing and other tolerances in DMD 309 may result in an angular difference of approximately 0.5° or less. To accommodate variations in the orientation of DMD 309, the input angle of fourth light 308 to DMD 309 can be varied. This can be achieved by appropriately adjusting first reflector 305 and second reflector 307.

[0049] Adjustment causes the first reflector 305 to tilt to move the light beam to the left. Figure 3B In the particular example shown, the first reflector 305 is positioned relative to Figure 3AThe position in the middle has a 0.5° counterclockwise tilt adjustment. Tilt the second reflector 307 to move the beam upward, which corresponds to relative to Figure 3A Together, these tilt adjustments accommodate orientation deviations in the DMD 309 so that the fifth light 310 remains centered on the aperture 310. The first mirror 305 and the second mirror 307 can be actuated by, for example, servo motors.

[0050] Adjustments to the first and second mirrors 305, 307 may be made during calibration of the projection system 100. Calibration may occur in real time (eg, after the projection system 100 is installed and before or during image projection) or during manufacturing.

[0051] Dual mirror alignment method

[0052] Figure 4 An exemplary alignment method is shown, which can be used in Figures 3A-3B A calibration of the portion of the optical system 300 shown is performed during operation. Figure 4 The alignment method may be performed in an automated manner; for example by a computer program, which will be described in more detail below.

[0053] In operation 401, an alignment method determines the orientation angle of the DMD 309, or the deviation of the orientation angle from an expected angle. The orientation angle can be determined directly, for example, by physically measuring the orientation angle of the DMD 309 in the projection system 100. Additionally or alternatively, the orientation angle can be determined indirectly, for example, by illuminating the DMD 309 at a known angle and measuring the output angle of the reflected light. In some embodiments, operation 401 can be performed in a test fixture before the DMD 309 is mounted on its prism assembly.

[0054] In operation 402, the alignment method calculates the appropriate angular adjustment amount for the first reflector 305 and the second reflector 307 based on the measured orientation angle (or deviation) of the DMD 309. The appropriate angular adjustment amount may be an amount that causes the fifth light 310 to be focused on the aperture 310. The calculation of operation 402 can be performed using a computer program that receives a single input (the orientation angle of the DMD 309, or the orientation angle of the DMD 309 relative to the desired angle) and outputs the orientation angles of the first reflector 305 and the second reflector 307. An exemplary calculation process that takes the difference between the orientation angle of the DMD 309 and the desired angle ("dmddeltheta") as input to perform ray tracing is shown in Table 1 in a MATLAB-like pseudo-code format.

[0055] Table 1:

[0056]

[0057]

[0058] The calculation outputs of Table 1 are the adjusted orientation angle of the first mirror 305 ("farmirrortheta"), the adjusted orientation angle of the second mirror 307 ("nearmirrortheta"), and the change in focus ("deltafocus"). The change in focus may result in some degree of defocus; however, depending on the f-number of the projection system 100, the change in focus may not be detectable. The inputs and outputs of the calculations of Table 1 are given in Table 1. Figure 5A In addition, Figure 5B The farmirrortheta (501) and nearmirrortheta (502) are shown as a function of dmdeltheta. Figures 5A-5B An example is shown where the magnitude of farmirrortheta is between zero and 0.1267 degrees and the magnitude of nearmirrortheta is between zero and 0.3737 degrees, but the disclosure is not limited thereto. In some examples (and depending on the relative positions of the first mirror 305 and the second mirror 307), the magnitude of farmirrortheta can be between zero and 0.2 degrees and the magnitude of nearmirrortheta can be between zero and 0.6 degrees.

[0059] from Figure 5A As can be seen, any changes in the system's focus are small (2 μm or less). Depending on the system parameters, the shift in focus may not become noticeable until the change exceeds about 20 μm, and is typically more noticeable for projection systems with small f-stops. In some implementations, the projection system 100 has an f-stop of f15 or higher. In such implementations, the effect on the focus of the system 100 is undetectable. However, if the projection system 100 has a very small f-stop, in one example, at least one of the first reflector 305 or the second reflector 307 should be translated in addition to being rotated. In another example, the position of the illumination lens system 303 along the optical axis of the first light 302 can be adjusted to maintain focus.

[0060] The calculations of operation 402 may be performed at calibration time, or may be pre-performed and stored in a lookup table associated with projection system 100. In such an implementation, the calibration method may calculate the appropriate mirror angle adjustments by referencing the lookup table rather than performing the operations shown in Table 1.

[0061] After the above calculations at operation 402, the alignment method actuates the mirror to impart the calculated orientation thereon at operation 403. Such actuation may be accomplished using a stepper motor, a servo motor, or other suitable adjustment mechanism. In some examples, Figure 1 The actuation is performed under the control of the controller 112. In other examples, the actuation is performed under manual control.

[0062] Mechanical pivot alignment control system

[0063] Although Figures 3A-5B A dual-mirror implementation of the projection system 100 is shown, but the present disclosure is not limited thereto. In another exemplary embodiment of the present disclosure, the above can be implemented by using a single mirror and by adjusting the angle of the mirror and its position.

[0064] In any such implementation, changes in the mirror position will result in changes in the aperture focus. Thus, for each angle adjustment, the illumination optics 103 should be refocused. However, focus adjustments also result in small changes in the proper position of the mirror, so multiple adjustments may be performed to achieve the proper combination of focus, position, and angle.

[0065] Figure 6 600 according to the present disclosure. In particular, Figure 6 Shown are an illumination lens system 601 (which may include one or more individual lenses), a first light 602, a reflector 603, a second light 604, a DMD 605, a third light 606, a virtual light path 607, and a virtual pivot point 608. For purposes of explanation, Figure 6 The portion of optical system 600 in FIG. 5 is shown in an orientation where first light 602 propagates generally vertically. Figure 6 The various elements shown may correspond to Figure 1 Various elements (or portions of various elements) are shown.

[0066] In some assemblies, illumination lens system 601 can be a component of illumination optical system 103 that receives first light 102 or intermediate light from an upstream optical component within illumination optical system 103. Illumination lens system 601 transmits the received light as first light 602 to reflector 603, which can be formed of or coated with any highly reflective material, such as aluminum or silver, to specularly reflect first light 602 as second light 604.

[0067] DMD 605 may correspond to DMD 105. For ease of explanation, DMD 605 is illustrated as a flat surface; however, in reality, DMD 605 includes multiple individual reflective elements that may or may not be oriented along the same plane. Thus, DMD 605 may have a configuration such as Figures 2A-2B The structure shown can selectively reflect and direct second light 604 depending on whether the various reflective components of DMD 605 are in an on position, a closed position, or a neutral position. Thus, third light 606 can correspond to third light 106 and can be directed to and focused on downstream components to provide an appropriate contrast ratio and image clarity.

[0068] In the comparative example, if there were no mirrors, and therefore the light path from the illumination optics was directed from the illumination aperture to the DMD at the correct angle and correct focus, and the system had a configuration in which the components had a single-axis pivot point located at the center of the DMD surface, then the angle of illumination could be adjusted without affecting the position or focus of the aperture image. However, this comparative example was not implemented in a configuration that included a mirror (e.g., a fold mirror or total internal reflection in a prism). Therefore, in order to reproduce the effect of such a pivot, Figure 6 A virtual pivot simulation is further shown.

[0069] exist Figure 6 In FIG, because the individual reflective elements of DMD 605 pivot on a single axis, and because sufficient contrast ratio and projected image clarity rely on correction of the different mirror pivot angles, the optical path of light incident on DMD 605 can similarly pivot only about the same single axis. To illustrate this point, Figure 6 Also shown are a virtual light path 607 and a virtual pivot point 608. If the reflector 603 were not present, the virtual light path 607 would track the trajectory of the first light 602. The virtual pivot point 608 represents the surface of the DMD 605 but is not physically located on that surface. Figure 6 An example is shown where only one reflective element is present in the optical path, but even in a system with multiple reflective elements (e.g., mirrors, total internal reflection prisms, etc.), the virtual pivot point 608 can be found by expanding all reflections (e.g., by determining and utilizing multiple virtual optical paths). In any case, if the source of the first light 602 (e.g., the illumination lens system 601) is physically rotated about the virtual pivot point, the position and focus will not change when the angle of the reflective surface of the DMD 605 is adjusted. A mechanical linkage can be used to achieve this rotation.

[0070] Figure 7 An exemplary mechanical linkage configuration is shown. Figure 7In the Figures 1 and 2, the solid circles represent connector hinges that have a fixed position, which can be called "grounded" hinges. The hollow circles represent connector hinges that are free to translate. Figure 7 Shown are a first fixed connector hinge 701, a second fixed connector hinge 702, a first connector 711 having a first end connected to the first fixed connector hinge 701, a second connector 712 having a first end connected to the second fixed connector hinge 702, a first free hinge 721 connected to the second end of the first connector 711, a second free hinge 722 connected to the second end of the second connector 712, a carrier 731, and a pivot point 741 that may coincide with a third free hinge. The first connector 711, the second connector 712, and the carrier 731 are rigid bodies. Figure 7 In the left part, the carrier 731 is in an unadjusted configuration. In this configuration, the first connector 711 and the second connector 722 are pointing to the pivot point position. Figure 7 , the carrier 731 has been rotated counterclockwise to provide the desired rotation and accommodate the orientation angle of the DMD 605.

[0071] As a result of the counterclockwise rotation, the position of the pivot point 741 moves only a small amount. The amount by which the focal position changes depends on the respective lengths of the first connector 711 and the second connector 722, and the amount by which the pivot point position changes depends on the specific geometry of the linkage implementation.

[0072] Figure 8 Another example linkage 800 is shown. Figure 8 Shown are a first fixed connector hinge 801, a second fixed connector hinge 802, a first connector 811 having a first end connected to the first fixed connector hinge 801, a second connector 812 having a first end connected to the second fixed connector hinge 802, a first free hinge 821 connected to the second end of the first connector 811, a second free hinge 822 connected to the second end of the second connector 712, a carrier 731, and a pivot point 841. The first connector 811, the second connector 812, and the carrier 831 are rigid bodies. The carrier 831 has a generally coffin-like shape; however, because the pivot point 841 should not be part of the optical surface, in practice the uppermost portion of the carrier 831 can be cut away (by Figure 8 In one specific example, including Figure 8 The optical path of the system of the exemplary linkage configuration has an optical path of approximately 500 mm, which is close to the minimum practical length of a D-Cinema DMD device having a diagonal of approximately 35 mm.

[0073] Figure 8The linkage 800 is driven by a combination of a drive mechanism 851, a drive hinge 852, and a drive connector 853, which extends between the drive hinge 852 and the lower vertex of the carrier 831. The action of the drive mechanism transmitted to the carrier 831 via the drive connector 853 provides translation of the carrier 831. Figure 7 Compared to the linkage shown, Figure 8 The linkage 800 shown can result in smaller changes in the position of the pivot point 841. In one specific example, a rotation applied to accommodate an angular shift in the light path from 0° to 0.5° (e.g., due to a change in the orientation angle of the reflective elements of the DMD) can result in a 0.06 μm translation of the pivot point. Such a translation would be undetectable. The position shift of the focus could be larger (e.g., ~13 μm), which might not be detectable with an optical system having an f-number of f20 or f15. In any case, the properties and structure of the DMD itself can mitigate the effects of focus changes or confine the effects to the edges.

[0074] In practical implementation, bearings (e.g. Figure 7-8 The effect of clearance in the bearings in the various hinges shown in can itself affect the location of the virtual pivot point. However, this can be mitigated by modifying the geometry of the linkage to make it more tolerant of bearing clearance. Figures 9A-9B An example of such a geometry for linkage 900 is shown.

[0075] Figure 9A -B shows a first fixed connector hinge 901, a second fixed connector hinge 902, a first connector 911 having a first end connected to the first fixed connector hinge 901, a second connector 912 having a first end connected to the second fixed connector hinge 902, a first free hinge 921 connected to the second end of the first connector 911, a second free hinge 922 connected to the second end of the second connector 912, a carrier 931, and a pivot point 941. The first connector 911, the second connector 912 and the carrier 931 are rigid bodies. The carrier 931 has a generally coffin-like shape; however, because the pivot point 941 should not be part of the optical surface, in practice the uppermost portion of the carrier 931 can be cut away (by Figure 9A -Dotted line in B). Figure 9A The linkage 900 is shown in an unrotated position, Figure 9B The linkage 900 is shown in a rotated position.

[0076] The linkage 900 is driven by a combination of a drive mechanism 951, a drive hinge 952, and a drive connector 953, with a drive connector 953 extending between the drive hinge 952 and the lower vertex of the carrier 931. The motion of the drive mechanism transmitted to the carrier 931 via the drive connector 953 provides translation of the carrier 931.

[0077] and Figure 8 The angle between the first and second connectors (in Figures 9A-9B The angle between the first connector 911 and the second connector 912 is larger. The increase in angle increases the tolerance of the bearing clearance of the linkage 900 to an angle of 45°, which is Figures 9A-9B . However, this change may result in a slightly larger focus change (e.g., 16 μm vs. 13 μm). In the event that this increase causes the focus change to become significant, the lengths of the first connector 911 and the second connector 912 can be increased to compensate while maintaining the angle between them. The amount of increase in the length of the first connector 911 and the second connector 912 is limited by the coefficient of thermal expansion of the materials of the first connector 911 and the second connector 912.

[0078] To further reduce the amount of bearing play in the linkage 900, a preload can be applied to the bearings. In addition to the axial preload (e.g., two bearings per pivot point), a spring can be added that is attached to the bottom surface of the carrier 931 at one end and to a fixed point (e.g., the ground) at the other end. In some examples, the carrier 931 is provided with a slot to allow a bolt (or other fastening mechanism) to lock the linkage 900 in place after adjustment. In some examples, the slot can be provided in a straight line between the first connector 921 and the second connector 922.

[0079] In some implementations, the optical system 100 includes a linkage having a configuration similar to Figure 8 and 9A -9B, and the angle between the first and second connectors is between 10° and 40°, and its length is sufficient to maintain the desired focus. In a specific example, the angle is 30° and the length is greater than or equal to 500 mm.

[0080] Regardless of the specific linkage structure used, the various parts of the illumination optics 103, including but not limited to Figure 6 The components shown can be mounted on a carrier. Figure 10 Shows the use of Figures 9A-9B One such example of such a configuration is the linkage arrangement 900. Figure 10In the embodiment, a portion of optical system 1000 includes the linkage shown in FIG9 , with an integrator rod 1001 and an illumination lens system 1002 mounted on a carrier 931. In some examples, integrator rod 1001 may be a component of light source 101, receiving light from the light-emitting elements of light source 101; however, in other examples, integrator rod 1001 may be a component of illumination optics 103. Other methods of producing uniform illumination, such as a fly's eye assembly, may be used in place of an integrator rod.

[0081] The linkage may be adjusted during calibration of the projection system 100 to compensate for angular misalignment of the DMD 605. Calibration may occur in real time (eg, after the projection system 100 is installed and before or during image projection) or during manufacturing.

[0082] Mechanical pivot alignment method

[0083] Figure 11 An exemplary alignment method is shown, which can be Figure 10 The portion of the optical system 1000 shown is performed during calibration. Figure 11 The alignment method can be performed partially or fully as an automated process.

[0084] In operation 1101, alignment determines the orientation angle of the DMD 605. The orientation angle can be determined directly, for example, by physically measuring the orientation angle of the DMD 605 in the projection system 100. Additionally or alternatively, the orientation angle can be determined indirectly, for example, by illuminating the DMD 605 at a known angle and measuring the output angle of the reflected light. In some implementations, operation 1101 can be performed in a test fixture before the DMD 605 is mounted on its prism assembly.

[0085] At operation 1102, the alignment method calculates appropriate linkage adjustments for linkage 900 based on the measured orientation angle of DMD 605. Operation 1102 may include first calculating appropriate rotational and / or translational adjustments to be made to carrier 931, and then determining corresponding linkage adjustments of linkage 900 that will result in such rotational and / or translational adjustments.

[0086] The calculations of operation 1102 can be performed at calibration time, or can be performed in advance and stored in a lookup table associated with projection system 100. In such an implementation, the calibration method can calculate the appropriate rotation and / or translation adjustments by referencing the lookup table, rather than performing the calculations at calibration time. In other examples, the calibration method can calculate the appropriate rotation and / or translation adjustments at calibration time, and can use the lookup table to determine the corresponding linkage adjustments.

[0087] After the calculation in operation 1102, the alignment method drives the linkage to impart the calculated orientation thereto in operation 1103. This actuation can be achieved by using a stepper motor, servo motor, or other suitable adjustment mechanism as the drive mechanism 951. The drive mechanism 951 can be composed of Figure 1 The controller 112 is shown controlling the operation 1103. Operation 1103 also includes fixing the linkage after the linkage is driven to the appropriate orientation. In some examples, fixing and / or adjusting the linkage can be performed manually.

[0088] Effect

[0089] The projection system and calibration method described above can provide a configuration having illumination optics that are capable of adjusting and maintaining the proper illumination angle, maintaining the focus of the aperture, maintaining the position of the aperture, and performing all of this in a configuration that uses prisms and folding mirrors.

[0090] Systems, methods, and devices according to the present disclosure may employ any one or more of the following configurations.

[0091] (1) A projection system comprising: a light source configured to emit light in response to image data; an illumination optical system configured to guide the light, the illumination optical system comprising a first reflector and a second reflector; a digital micromirror device comprising a plurality of micromirrors, wherein each micromirror is configured to reflect the guided light as on-state light to a filter when the lens is in an on position, and to reflect the guided light as off-state light to a light collector when the lens is in a closed position; and a controller configured to: determine a deviation between an actual orientation angle of the digital micromirror device and an expected orientation angle of the digital micromirror device, calculate a first angle adjustment amount corresponding to the first reflector and a second angle adjustment amount corresponding to the second reflector, and actuate the first reflector according to the first amount and actuate the second reflector according to the second amount, thereby maintaining the position and focus of the guided light on the digital micromirror device and causing the on-state light to be incident within a predetermined distance from the center of the filter.

[0092] (2) The projection system according to (1), wherein the first reflector is located optically upstream of the second reflector.

[0093] (3) The projection system according to (2), wherein the first amount is smaller than the second amount.

[0094] (4) The projection system according to any one of (1) to (3), wherein the first amount and the second amount are proportional to the deviation.

[0095] (5) The projection system according to any one of (1) to (4), further comprising a filter, wherein the filter includes an aperture.

[0096] (6) The projection system of any one of (1) to (5), wherein the first amount is between zero and 0.2 degrees.

[0097] (7) The projection system of any one of (1) to (6), wherein the second amount is between zero and 0.6 degrees.

[0098] (8) The projection system according to any one of (1) to (7), wherein the aperture value of the projection system is f15 or higher.

[0099] (9) The projection system according to any one of (1) to (8), wherein the position of the guided light on the digital micromirror device is maintained within 20 μm.

[0100] (10) The projection system according to any one of (1) to (9), wherein the first quantity or the second quantity includes a rotational displacement and a translational displacement.

[0101] (11) A method for calibrating a projection system, the projection system comprising a light source configured to emit light in response to image data; an illumination optical system configured to guide the light, the illumination optical system comprising a first reflector and a second reflector; a digital micromirror device comprising a plurality of micromirrors, wherein the plurality of micromirrors are respectively configured to reflect the guided light as on-state light to a filter when the lens is in an on position, and to reflect the guided light as off-state light to a light collector when the lens is in a closed position, the method comprising: determining a deviation between an actual orientation angle of the digital micromirror device and an expected orientation angle of the digital micromirror device, calculating a first angle adjustment amount corresponding to the first reflector and a second angle adjustment amount corresponding to the second reflector, and actuating the first reflector according to the first amount and actuating the second reflector according to the second amount, thereby maintaining the position and focus of the guided light on the digital micromirror device and causing the on-state light to be incident within a predetermined distance from the center of the filter.

[0102] (12) The method of (11), wherein determining the deviation includes directly measuring the orientation angle of the digital micromirror device.

[0103] (13) The method of (11) or (12), wherein determining the deviation includes illuminating the digital micromirror device with light from a light source and measuring an output angle of light reflected from the digital micromirror device.

[0104] (14) The method according to any one of (11) to (13), wherein calculating the first quantity and the second quantity includes calculating a ray trace based on the deviation quantity.

[0105] (15) The method according to any one of (11) to (14), wherein calculating the first quantity and the second quantity includes using a lookup table based on the deviation quantity.

[0106] (16) The method according to any one of (11) to (15), wherein the first amount and the second amount are proportional to the deviation.

[0107] (17) The method according to any one of (11) to (16), wherein the expected orientation angle of the digital micromirror device is a first predetermined angle in the on position and a second predetermined angle in the off position.

[0108] (18) The method according to any one of (11) to (17), wherein the position of the guided light on the digital micromirror device is maintained within 20 μm.

[0109] (19) The method according to any one of (11) to (18), wherein actuating the first reflector includes rotating the first reflector and translating the first reflector, or actuating the second reflector includes rotating the second reflector and translating the second reflector.

[0110] (20) A non-transitory computer-readable medium storing instructions that, when executed by a processor of a projection system, cause the projection system to perform operations including the method according to any one of (11) to (19).

[0111] (21) A projection system comprising: a light source configured to emit light in response to image data; an illumination optical system configured to guide the light, the illumination optical system comprising a reflector and a linkage; a digital micromirror device comprising a plurality of micromirrors, wherein each micromirror is configured to reflect the guided light as on-state light to a filter when the lens is in an on position, and to reflect the guided light as off-state light to a light collector when the lens is in a closed position; a filter comprising an aperture; and a controller configured to: determine a deviation between an actual orientation angle of the digital micromirror device and an expected orientation angle of the digital micromirror device, calculate an adjustment amount of the linkage, and adjust the linkage according to the adjustment amount, thereby maintaining the position and focus of the guided light on the digital micromirror device and causing the reflected light to be incident within a predetermined distance from the center of the filter.

[0112] (22) The projection system of (21), wherein the controller is configured to actuate the linkage to pivot about a pivot point.

[0113] (23) The projection system of (22), wherein the pivot point corresponds to a virtual position of the digital micromirror device when there is no reflection.

[0114] (24) The projection system according to any one of (21) to (23), wherein the linkage device includes a carrier, a first connector, and a second connector.

[0115] (25) The projection system of (24), wherein the first connector includes a first end attached to a first fixed hinge and a second end attached to a first free hinge, wherein the first free hinge is located on the carrier.

[0116] (26) The projection system of (24) or (25), wherein the second connector includes a first end attached to the second fixed hinge and a second end attached to the second free hinge, wherein the second free hinge is located on the carrier.

[0117] (27) The projection system according to any one of (24) to (26), wherein an angle formed by the first connector and the second connector is between 10° and 40°.

[0118] (28) The projection system according to any one of (24) to (27), wherein an angle formed by the first connector and the second connector is 30°.

[0119] (29) The projection system according to any one of (24) to (27), wherein the respective lengths of the first connector and the second connector are greater than or equal to 500 mm.

[0120] (30) The projection system according to any one of (24) to (29), wherein the linkage device further includes a driving mechanism configured to actuate the carrier.

[0121] (31) The projection system according to any one of (24) to (30), wherein the integrator rod is mounted on a carrier.

[0122] (32) The projection system according to any one of (24) to (31), wherein the carrier has a coffin-like shape.

[0123] (33) A projection system according to any one of (21) to (32), wherein the expected orientation angle of the digital micromirror device is a first predetermined angle in the on position and a second predetermined angle in the off position.

[0124] (34) A method for calibrating a projection system, the projection system comprising: a light source configured to emit light in response to image data; an illumination optical system configured to guide light, the illumination optical system comprising a reflector and a linkage; a digital micromirror device comprising a plurality of micromirrors, wherein the plurality of micromirrors are respectively configured to reflect the guided light as on-state light to a filter when the lens is in an on position, and to reflect the guided light as off-state light to a light collector when the lens is in a closed position; and a filter comprising an aperture, the method comprising: determining a deviation between an actual orientation angle of the digital micromirror device and an expected orientation angle of the digital micromirror device, calculating an adjustment amount of the linkage, and adjusting the linkage according to the adjustment amount, thereby maintaining the position and focus of the guided light on the digital micromirror device and causing the reflected light to be incident within a predetermined distance from the center of the filter.

[0125] (35) The method according to (34) also includes fixing the linkage in one orientation after actuation.

[0126] (36) A method according to (34) or (35), wherein actuating the linkage comprises pivoting the linkage about a pivot point.

[0127] (37) The method of (36), wherein the pivot point corresponds to a virtual position of the digital micromirror device when there is no reflection.

[0128] (38) A method according to any one of (34) to (37), wherein actuating the linkage device includes actuating the carrier through a drive mechanism.

[0129] (39) A method according to any one of (34) to (38), wherein calculating the adjustment amount includes calculating the rotation, translation, or rotation and translation adjustment to be performed on the carrier of the linkage device, and determining the value of the adjustment amount corresponding to the rotation, translation, or rotation and translation adjustment.

[0130] (40) A non-transitory computer-readable medium storing instructions that, when executed by a processor of a projection system, cause the projection system to perform operations including the method according to any one of (34) to (39).

[0131] With respect to the processes, systems, methods, heuristics, and the like described herein, it should be understood that although the steps of these processes, and the like, have been described as occurring according to a particular ordered sequence, these processes can be implemented with the described steps performed in an order different from that described herein. It should also 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 not be construed to limit the claims in any way.

[0132] Therefore, it should be understood that the above description is illustrative and not restrictive. Upon 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 rather with reference to the appended claims and the full scope of equivalents to such claims. It is expected that future developments will occur in the technology discussed herein, and the disclosed systems and methods will be incorporated into such future embodiments. In short, it should be understood that the present application is capable of modification and variation.

[0133] Unless otherwise expressly indicated herein, all terms used in the claims are intended to be given their broadest reasonable interpretations and ordinary meanings as understood in the art described herein. In particular, use of singular articles such as "a," "an," "the," and the like should be understood to recite one or more of the indicated elements unless a claim provides an explicit limitation to the contrary.

[0134] This Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Furthermore, in the foregoing Detailed Description, it can be seen that various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments incorporate more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive subject matter lies in less than all the features of a single disclosed embodiment. Accordingly, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as separately claimed subject matter.

Claims

1. A projection system comprising: a light source configured to emit light in response to image data; an illumination optical system configured to guide light, the illumination optical system comprising a first reflector and a second reflector; A digital micromirror device comprising a plurality of micromirrors, wherein each micromirror is configured to reflect guided light as on-state light to a filter when each micromirror is in an on position, and to reflect guided light as off-state light to a light collector when each micromirror is in an off position; as well as The controller is configured as: determining a deviation between an actual orientation angle of a digital micromirror device and an expected orientation angle of the digital micromirror device, calculating a first angle adjustment corresponding to the first reflector and a second angle adjustment corresponding to the second reflector, and Actuating the first reflector according to the first angular adjustment amount and actuating the second reflector according to the second angular adjustment amount maintains the position and focus of the guided light on the digital micromirror device and causes the on-state light to be incident within a predetermined distance from the center of the filter.

2. The projection system of claim 1, wherein the first reflector is located optically upstream of the second reflector. The projection system according to claim 2 , wherein the first angle adjustment amount is smaller than the second angle adjustment amount.

4. The projection system according to any one of claims 1 to 3, wherein: The first angle adjustment amount and the second angle adjustment amount are proportional to the deviation.

5. The projection system of any one of claims 1-3, further comprising a filter, wherein the filter comprises an aperture.

6. The projection system according to any one of claims 1 to 3, wherein: The first angle adjustment amount or the second angle adjustment amount includes a rotational displacement and a translational displacement.

7. A method for calibrating a projection system, the projection system comprising: a light source configured to emit light in response to image data; an illumination optical system configured to guide light, the illumination optical system comprising a first reflector and a second reflector; A digital micromirror device comprising a plurality of micromirrors, each of the plurality of micromirrors being configured to reflect the guided light as on-state light to a filter when each micromirror is in an on position, and to reflect the guided light as off-state light to a light collector when each micromirror is in an off position; and the controller, The method comprises, by the controller: determining a deviation between an actual orientation angle of a digital micromirror device and an expected orientation angle of the digital micromirror device, calculating a first angle adjustment corresponding to the first reflector and a second angle adjustment corresponding to the second reflector, and Actuating the first reflector according to the first angular adjustment amount and actuating the second reflector according to the second angular adjustment amount maintains the position and focus of the guided light on the digital micromirror device and causes the on-state light to be incident within a predetermined distance from the center of the filter.

8. The method of claim 7, wherein determining the deviation comprises directly measuring the orientation angle of the digital micromirror device.

9. The method of claim 7, wherein determining the deviation comprises illuminating the DMD with light from a light source and measuring an output angle of the light reflected from the DMD. 10 . The method according to claim 7 , wherein calculating the first angle adjustment amount and the second angle adjustment amount comprises calculating a ray trajectory based on a deviation amount.

11. The method of any one of claims 7-9, wherein calculating the first angle adjustment amount and the second angle adjustment amount comprises using a lookup table based on an offset amount.

12. The method according to any one of claims 7 to 9, wherein the first angle adjustment amount and the second angle adjustment amount are proportional to the deviation.

13. The method according to any one of claims 7 to 9, wherein the expected orientation angle of the digital micromirror device is a first predetermined angle in the on position and a second predetermined angle in the off position.

14. The method of any one of claims 7 to 9, wherein actuating the first reflector comprises rotating the first reflector and translating the first reflector, or actuating the second reflector comprises rotating the second reflector and translating the second reflector.

15. A non-transitory computer-readable medium storing instructions, which, when executed by a processor of a projection system, cause the projection system to perform operations including the method according to any one of claims 7 to 14.

Images