Projection system and method employing folding mirrors and integrating rod adjustment

Abstract

A projection system and a calibration method thus involve a light source configured to emit light in response to image data, an illumination optical system configured to turn the light, the illumination optical system comprising a folding mirror and an integrator rod, a digital micromirror device (DMD) comprising a plurality of micromirrors respectively configured to reflect the turned light as on-state light to a predetermined location or to reflect the turned light as off-state light to a light collector, determining a deviation between an actual orientation angle and an expected orientation angle of a respective micromirror of the plurality of micromirrors, calculating a first rotational adjustment amount corresponding to the folding mirror and a second lateral adjustment amount corresponding to the integrator rod, and actuating the folding mirror and the integrator rod in accordance with the corresponding first and second amounts.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 104,855, filed October 23, 2020, the entire contents of which are incorporated herein by reference in their entirety. background 1. Technical Field

[0004] This application generally relates to projection systems and methods for calibrating projection systems. 2. Background Technology

[0006] Digital projection systems typically use light sources and optical systems to project images onto a surface or screen. Optical systems include components such as mirrors, lenses, waveguides, optical fibers, beam splitters, diffusers, and spatial light modulators (SLMs). A projector's contrast ratio indicates the projector's brightest output relative to its darkest output. The contrast ratio is a quantitative measure of contrast, defined as the ratio of the projector's brightest output brightness to its darkest output brightness. This definition of contrast ratio is also known as the "static" or "native" contrast ratio.

[0007] Some projection systems are based on spatial amplitude modulation (SLM). In such systems, the light source can provide a light field that achieves the brightest level reproducible on 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 architecture use a semi-collimated illumination system and a small aperture stop in the projection optics to improve contrast. In such an architecture, the illumination angle on the SLM has a substantial impact on the projected image, including but not limited to its effect on the contrast ratio and sharpness of the projected image. Summary of the Invention

[0008] Various aspects of this disclosure relate to apparatus, systems, and methods for projecting displays onto high-contrast projection architectures.

[0009] In one exemplary aspect of this disclosure, a projection system is provided, comprising: a light source configured to emit light in response to image data; an illumination optics system configured to deflect the light, the illumination optics system including an integrating bar and a folded mirror; a digital micromirror device including a plurality of micromirrors, wherein a respective micromirror is configured to reflect the deflected light as on-state light to a predetermined position when the respective micromirror is in an on position, and to reflect the deflected light as off-state light to a light collector when the respective micromirror is in a closed position; and a controller configured to: determine the actual orientation of a respective micromirror among the plurality of micromirrors of the digital micromirror device. The deviation between the angle and the target orientation angle of the corresponding micromirror among the plurality of micromirrors of the digital micromirror device; based on the deviation between the actual orientation angle and the target orientation angle of the corresponding micromirror among the plurality of micromirrors of the digital micromirror device, calculate a first rotational adjustment amount corresponding to the folding mirror and a second lateral adjustment amount corresponding to the integrating bar; rotate the folding mirror by an angle corresponding to the first amount and actuate the integrating bar in a first direction according to the second amount, wherein the second amount is based on the first amount and is configured to change the incident angle of the redirected light on the corresponding micromirror in response to the deviation and maintain the position of the redirected light on the corresponding micromirror.

[0010] In another exemplary aspect of this disclosure, a method for calibrating a projection system is provided, the projection system comprising: a light source configured to emit light in response to image data; an illumination optics system configured to deflect the light, the illumination optics system including an integrating bar and a folded mirror; and a digital micromirror device including a plurality of micromirrors, the plurality of micromirrors being configured to reflect the deflected light as on-state light to a predetermined position when the respective micromirror is in an on position, and to reflect the deflected light as off-state light to a light collector when the respective micromirror is in a closed position, the method comprising: determining the actual position of a corresponding micromirror among the plurality of micromirrors of the digital micromirror device. The deviation between the orientation angle and the target orientation angle of the corresponding micromirror among the plurality of micromirrors of the digital micromirror device; based on the deviation between the actual orientation angle and the target orientation angle of the corresponding micromirror among the plurality of micromirrors of the digital micromirror device, calculate a first rotational adjustment amount corresponding to the folding mirror and a second lateral adjustment amount corresponding to the integrating bar; rotate the folding mirror by an angle corresponding to the first direction and actuate the integrating bar in the first direction according to the second amount, wherein the second amount is based on the first amount and is configured to change the incident angle of the redirected light on the corresponding micromirror in response to the deviation and maintain the position of the redirected light on the corresponding micromirror.

[0011] In another exemplary aspect of this disclosure, a non-transitory computer-readable medium is provided for storing instructions that, when executed by a processor of a projection device, include: a light source configured to emit light in response to image data; an illumination optics system configured to deflect the light, the illumination optics system including an integrating bar and a folded mirror; and a digital micromirror device including a plurality of micromirrors, each of the plurality of micromirrors being configured to reflect the deflected light as on-state light to a predetermined position when the respective micromirror is in an on position, and to reflect the deflected light as off-state light to a light collector when the respective micromirror is in a closed position, the method comprising: determining the plurality of micromirrors of the digital micromirror device. The deviation between the actual orientation angle of the corresponding micromirror in the digital micromirror device and the expected orientation angle of the corresponding micromirror in the plurality of micromirrors of the digital micromirror device; based on the deviation between the actual orientation angle and the target orientation angle of the corresponding micromirror in the plurality of micromirrors of the digital micromirror device, a first rotation adjustment amount corresponding to the folding mirror and a second lateral adjustment amount corresponding to the integrating bar are calculated; the folding mirror is rotated by an angle corresponding to the first direction and the integrating bar is actuated in the first direction according to the second amount, wherein the second amount is based on the first amount and is configured to change the incident angle of the redirected light on the corresponding micromirror in response to the deviation and maintain the position of the redirected light on the corresponding micromirror.

[0012] In this way, various aspects of this disclosure provide for the display of images with high dynamic range and high resolution, and provide effective improvements in at least the fields of image projection, holography, signal processing, etc. Attached Figure Description

[0013] Referring to the accompanying drawings, these and other more detailed and specific features of various embodiments are disclosed more fully in the following description, in which:

[0014] Figure 1 A block diagram of an exemplary projection system according to various aspects of this disclosure is illustrated;

[0015] Figure 2A The illustration shows a plan view of an exemplary spatial light modulator used in conjunction with various aspects of this disclosure;

[0016] Figure 2B The diagram illustrates the following: along Figure 2A A cross-sectional view taken from line 2B;

[0017] Figures 3A to 3C The illustration shows exemplary optical states in an exemplary projection system according to various aspects of the present disclosure;

[0018] Figure 4 The diagram shows... Figures 3A to 3CAn exemplary adjustment method in an exemplary optical system;

[0019] Figure 5 Exemplary calibration systems according to various aspects of this disclosure are illustrated; and

[0020] Figure 6 The diagram shows... Figure 5 An exemplary calibration method for an exemplary calibration system. Detailed Implementation

[0021] This disclosure and its aspects can 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; and hardware-implemented methods, signal processing circuits, memory arrays, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), etc. The foregoing description is intended only to give a general idea of ​​the various aspects of this disclosure and does not limit the scope of this disclosure in any way.

[0022] In the following description, numerous details such as optical device configuration, timing, and operation are set forth to provide an understanding of one or more aspects of this 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 this application.

[0023] Furthermore, while this disclosure focuses primarily on examples of using various circuits in digital projection systems, it should be understood that this is merely one example of an implementation. It should also be understood that the disclosed systems and methods can be used in any device that requires the projection of light; for example, cinema projection systems, consumer projection systems and other commercial projection systems, head-up displays, virtual reality displays, etc.

[0024] Projector system

[0025] The optics of a projection system based on an illumination optics (SLM) can be broadly classified into two parts: optics located on the illumination side (i.e., upstream of the SLM) and optics located on the projection side (i.e., downstream of the SLM). The SLM itself comprises multiple modulation elements arranged, for example, in a two-dimensional array. Each modulation 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, generally, a DMD comprises a two-dimensional array of reflective elements (micromirrors or simply “mirrors”) that selectively reflect or discard light toward the projection optics based on the position of each reflective element.

[0026] As mentioned above, high-contrast projection systems using semi-collimated illumination systems and small aperture stops in projection optics can be significantly affected by differences in the angle of incidence of light on the DMD (also known as the “input angle”). To prevent projection image degradation, the projection system can maintain the position and focus of the output of the illumination optics (e.g., light output from an integrating bar or other uniformity correction device and subsequently reflected by one or more reflective elements) on the DMD, while simultaneously keeping the reflected beam centered within the aperture stop (e.g., filter aperture) of the projection optics. However, the exact position of the DMD mirror angle (e.g., the corresponding orientation angle of the DMD mirror in the “on” and / or “off” positions, which will be described in more detail below) can be affected by manufacturing tolerances or other tolerances, causing the actual angle to vary to some extent. To compensate for the difference in DMD mirror angles between different physical DMDs and ensure proper beam centering, the angle of light exiting (e.g., reflected) from the DMD (also known as the “emission angle”) can be controlled. Such control should be robust to variations in the first and second angles of the DMD mirror. Robustness to angular variations can be provided by adjusting the incident angle of the beam on the DMD so that when reflected by the DMD mirror, the outgoing beam always strikes the aperture at (or substantially at) the nominal design outgoing angle. Furthermore, since each color channel in a color projection system may have different angular requirements, it is desirable to provide adjustment for each color.

[0027] In addition to adjusting and maintaining the appropriate illumination angle, the architecture of such high-contrast projection systems can provide specific constraints. For example, the projection system can utilize prisms in which three colors are recombined and / or folded mirrors in front of the prisms to reduce the size footprint of the optics and the projector itself. Furthermore, as mentioned above, the image of the integrating bar should be centered on the DMD. Examples of projection systems are described in this paper that are able to adjust the input angle of the beam directed towards the DMD without changing the focus or position of the image of the integrating bar (or other uniformity correction device) at the DMD.

[0028] Figure 1 An exemplary high-contrast projection system 100 according to various aspects of this disclosure is illustrated. Specifically, Figure 1The diagram illustrates a projection system 100, which includes: a light source 101 configured to emit a first light 102; an illumination optics 103 (an example of an illumination optics system according to the present disclosure) configured to receive the first light 102 and redirect or otherwise modify the first light to generate a second light 104; a DMD 105 configured to receive the second light 104 and selectively redirect and / or modulate the second light into a third light 106; a first projection optics 107 configured to receive the third light 106 and project the third light into a fourth light 108; a filter 109 configured to filter the fourth light 108 to generate a fifth light 110; and a second projection optics 111 configured to receive the fifth light 110 and project the fifth light as a sixth light 112 onto a screen 113.

[0029] In practical implementations, 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 screen 113, in one embodiment, Figure 1 The illustrated components can be integrated into a housing to provide a projection device. In other embodiments, the projection system 100 may include multiple housings. For example, a light source 101, an illumination optics 103, and a DMD 105 may be housed in a first housing, and a first projection optics 107, a filter 109, and a second projection optics 111 may be housed in a second housing that can mate with the first housing. In some further embodiments, one or more of these housings may themselves include sub-components. One or more housings of such a projection device may include additional components such as memory, input / output ports, communication circuitry, power supplies, etc.

[0030] Light source 101 may be, for example, a laser light source, an LED, etc. Generally, light source 101 is any light emitter that emits light. In some embodiments, the light is coherent light. In some aspects of this disclosure, light source 101 may include multiple individual light emitters, each corresponding to a different wavelength or wavelength band. Light source 101 emits light in response to an image signal provided by controller 114; the controller is, for example, one or more processors of projection system 100, such as a central processing unit (CPU). The image signal includes image data corresponding to multiple frames to be displayed sequentially. Various elements in projection system 100 (including illumination optics 103 and / or DMD 105) may be controlled by controller 114. The image signal may be derived from an external source, either streaming or cloud-based, from internal storage of projection system 100 such as a hard disk, from a removable medium operatively connected to projection system 100, or from a combination of the above.

[0031] Although Figure 1 The diagram illustrates a generally linear optical path, but in reality, optical paths are often more complex. For example, in projection system 100, a second light 104 from illumination optics 103 is directed at a certain tilt angle to DMD chip 105 (or multiple chips).

[0032] To illustrate the effect of the incident angle and the DMD mirror Figures 2A to 2B An exemplary DMD 200 according to various aspects of this disclosure is shown. Specifically, Figure 2A The diagram illustrates a plan view of the DMD 200, and Figure 2B The diagram illustrates the following: along Figure 2A The diagram shows a partial cross-sectional view of a DMD 200 taken along line II-B. The DMD 200 comprises 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). Each micromirror 202 may correspond to a pixel of the final projected image and may be configured to tilt about a rotation axis 208 (shown for a specific subset of the micromirrors 202) due to electrostatic or other types of actuation. Each micromirror 202 has a width 212 and is arranged to be spaced apart by gaps of width 210. The micromirrors 202 may be formed of or coated with any highly reflective material such as aluminum or silver, thereby specularly reflecting light. The gaps between the micromirrors 202 may be absorptive, such that input light entering the gaps is absorbed by the substrate 204.

[0033] Although Figure 2AOnly some representative micromirrors 202 are explicitly shown, but in reality, 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-grade 4K (3840×2160), etc. Furthermore, in some examples, the micromirrors 202 may be rectangular and arranged in a rectangular array; they may be hexagonal and arranged in a hexagonal array, etc. Moreover, although... Figure 2A The figure shows a rotation axis 208 extending in an inclined direction, but in some embodiments, the rotation axis 208 may extend vertically or horizontally.

[0034] like Figure 2B As can be seen, each micromirror 202 is rotatably connected to the substrate 204 via a yoke 214. The substrate 204 includes a plurality of electrodes 216. Although in Figure 2B In the cross-sectional view, only two electrodes 216 are visible for each micromirror 202, but each micromirror 202 can actually include additional electrodes. Although not shown in... Figure 2B As specifically illustrated, DMD 200 may also include spacer layers, support layers, hinge components for controlling the height or orientation of micromirror 202, etc. Substrate 204 may include electronic circuitry associated with DMD 200, such as CMOS transistors, memory elements, etc.

[0035] Depending on the specific operation and control of electrode 216, each micromirror 202 can switch between an "on" position, an "off" position, and an unactuated or neutral position. If micromirror 202 is in the on position, it is actuated by an angle of, for example, -12° (i.e., 12° counterclockwise relative to the neutral position) to mirror the input light 206 into on-state light 218. If micromirror 202 is in the off position, it is actuated by an angle of, for example, +12° (i.e., 12° clockwise relative to the neutral position) to mirror the input light 206 into 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, micromirror 202 may be unactuated and parallel to substrate 204. Figures 2A to 2B The specific angles illustrated and described herein are merely exemplary and not limiting. In some implementations, the open position angle and the closed position angle may be between ±11 degrees and ±13 degrees (inclusive).

[0036] exist Figure 1In the context of the DMD mirror using a 12° tilt angle to reflect or discard light, the second light 104 is redirected to the DMD chip 105 at a fixed angle of 24°. When the individual mirror is tilted at a first predetermined angle (e.g., -12°), the mirror is considered to be in the open state and redirects light to the first projection optics 107, the filter 109, and the second projection optics 111 (e.g., at predetermined positions). When the individual mirror is tilted at a second predetermined angle (e.g., +12°), the mirror is considered to be in the closed state and redirects light to a light collector located outside the active image area.

[0037] To ensure that the image on screen 113 has an acceptable sharpness and contrast ratio, the illumination optics 103 may be designed and / or controlled to ensure that the angle of incidence on DMD 105 is correct, while keeping the position of the second light 104 centered on DMD 105.

[0038] Integrating bar and folding mirror control system

[0039] In one exemplary embodiment of this disclosure, the above description can be achieved by using an integrating bar and a folding mirror. Figures 3A to 3C An exemplary optical configuration of a portion of the optical system 300 according to this disclosure is illustrated. The portion of the optical system 300 may be at least partially an example of the illumination optics 103 and the DMD 105.

[0040] Specifically, Figure 3A The illustration shows an integrating bar 301 or other uniformity correction device (only its output surface is shown), a first beam 302, a first lens group 303, a second beam 304, a folding mirror 305, a third beam 306, a second lens group 307, a fourth beam 308, and a DMD 309. For illustrative purposes, Figures 3A to 3CPart of the optical system 300 is illustrated with the first light 302 generally traveling vertically. Therefore, the integrating rod 301 travels generally horizontally (perpendicular to the first light 302). The integrating rod 301 is thus configured for lateral adjustment. The integrating rod 301 further has a range of motion defined by a first point and a second point. For example, the integrating rod 301 can be configured to move from a starting point (the position of the integrating rod 301 illustrated in FIG. 3) by up to -10 mm and +10 mm. In some embodiments, the lateral dimension (e.g., diameter, aperture) of the integrating rod 301 is large enough that the first light 102 can pass through the integrating rod 301 when it is positioned across its entire range of motion. For example, the lateral dimension of the integrating rod 301 can be greater than or equal to twice the maximum value of the range of motion. The folding mirror 305 is configured for rotational adjustment. The range of motion of the folding mirror 305 is defined by a third point and a fourth point. For example, the folding mirror 305 can be configured to move within a range of 15° to 75°, where 0° is defined as the folding mirror 305 being vertical. In some embodiments, the lateral dimension (e.g., diameter) of the folding mirror 305 is large enough that the second light 304 can be reflected from the surface of the folding mirror 305 when the folding mirror 305 is positioned across its entire range of motion. For example, the lateral dimension of the folding mirror 305 can be large enough that light from the light source 101 (or the integrating bar 301) still incident on the folding mirror 305 even when the folding mirror 305 is at its maximum range of motion and the integrating bar 301 is at its maximum range of motion.

[0041] The integrating bar 301 is located optically upstream of the folding mirror 305 (and therefore farther from the DMD). Additionally, the first lens group 303 is located optically upstream of the second lens group 307. In some embodiments, the folding mirror 305 may be positioned downstream of the second lens group 307. Figures 3A to 3C The various components shown in the diagram can be used with Figure 1 The various components (or parts of various components) shown in the diagram correspond to each other.

[0042] In some examples, the integrating bar 301 may be a component of the light source 101, receiving light from the light-emitting element of the light source 101 and emitting light, such that the first light 302 corresponds to the first light 102. In other examples, the integrating bar 301 may be a component of the illumination optics 103, such that the integrating bar 301 receives the first light 102 (e.g., light emitted by the light source 101). In such examples, the first light 302 is inside the illumination optics 103 and therefore not in the light source 102. Figure 1The diagram clearly illustrates this. In some examples, the first lens group 303, the folding mirror 305, and the second lens group 307 are components of the illumination optics 103, such that the fourth light 308 corresponds to the second light 104. In some embodiments, optical elements upstream of the integrating bar 301 (e.g., some or all of the optical components of the light source 101 and / or the illumination optics 303) can be configured to travel alongside the integrating bar 301. Such a configuration can be implemented to ensure uniformity and efficiency.

[0043] The first lens group 303 includes a first lens 310 and a second lens 311. The second lens group 307 includes a third lens 312 and a fourth lens 313. Although shown as including two lenses, the first lens group 303 and the second lens group 307 can be composed of any number of lenses to guide the first light 302 to the DMD 309 at a defined angle. Furthermore, although each individual lens is illustrated separately, the individual lenses within a lens group can be cemented together. Additionally, each lens group can be composed of any type of lens, such as a concave lens, a convex lens, a biconcave lens, a biconvex lens, a plano-concave lens, a plano-convex lens, a negative meniscus lens, and a positive meniscus lens.

[0044] DMD 309 can correspond to DMD 105. For ease of illustration, DMD 309 is shown as a flat surface; however, in reality, DMD 309 includes multiple individual reflective elements, which may or may not be oriented along the same plane. In this way, DMD 309 can have, for example... Figures 2A to 2B The illustrated structure is designed to selectively reflect and guide the fourth light 308 (i.e., the second light 104) depending on whether the various reflective elements of the DMD 309 are in an on, off, or neutral position. To provide an appropriate contrast ratio and image sharpness, the fourth light 308, once reflected by the DMD 309 (i.e., the third light 106), should be centered at a predetermined position, such as the aperture (e.g., the first projection optics 107, the filter 109, and the second projection optics 111).

[0045] exist Figure 3A In the illustrated configuration, the surface of the DMD 309 is oriented normally toward the fourth beam 308. The integrating bar 301 and the folding mirror 305 are each positioned such that the fourth beam 308 emanating from the second lens group 307 is centered on the DMD 309. Typically, the DMD should be illuminated with light at twice the tilt angle of the micromirrors, but for the sake of simplicity in demonstrating the principles of the invention, Figure 3AThe fourth light 308 is shown to contact the DMD 309 at 0° relative to the surface normal of the DMD 309. The first light 302 travels along the vertical optical axis from the integrating bar 301 to the first lens group 303. In effect, the first light 302 expands as it travels, such that it faces a non-zero solid angle toward the surface of the first lens group 303. The surface of the first lens group 303 receives the first light 302 and directs it as the second light 304 to the folding mirror 305. The surface of the folding mirror 305 reflects the second light 304 as the third light 306 to the second lens group 307, such that the fourth light 308 is centered on the DMD 309. When the micromirror 202 is “on”, the micromirror is tilted at -12°, and the fourth light 308 is projected through the projection lens. When the micromirror 202 is “off”, the mirror is tilted at +12°, and the fourth light 308 is projected onto the light collector, as described above.

[0046] However, in practice, any deviation in the nominal tilt angle of the micromirrors of DMD 309 (or DMD 105) will cause the incident point of the third beam 106 on the first projection optics 107 to shift. Similarly, the fourth beam 308 being angled relative to the surface of DMD 309 at any angle other than 0° may also no longer result in the third beam 106 being centered in the aperture stop 109. These shifts can be counteracted by adjusting the integrating bar 301 and the folding mirror 305. For example, as... Figure 3B As illustrated, the integrating bar 301 can be offset in a first direction 314. The folding mirror 305 can be rotated in a second direction 315. The first direction 314 is perpendicular (e.g., transverse) to the optical axis of the integrating bar 301 (e.g., the direction of the first light 302). The second direction 315 is an angular direction indicating the rotation of the folding mirror 305. Figure 3B In this context, the second direction 311 is either counterclockwise or negative. The offset of the integrating rod 301 and the folding mirror 305 causes a deflection of the light, ultimately changing the direction of the fourth light 108. However, the movement of the integrating rod 301 and the folding mirror 305 can keep the incident point of the fourth light 108 centered in the aperture. Although the incident point is centered, the angle of the light changes based on the amount of movement of the integrating rod 301 and the folding mirror 305.

[0047] For example, in order to offset the first exemplary deviation, such as Figure 3B The fourth light 308 shown in the figure is relative to Figure 3A The unbiased example is angled at 2°, so that the incident point remains centered on DMD 309. To achieve this, the integrating bar 301 is adjusted by a first amount (e.g., a first distance) in the first direction 310, and the folding bar 305 is adjusted by a second amount (e.g., a second distance) in the second direction 315.

[0048] To offset the second exemplary deviation, such as Figure 3C The fourth light 308 shown in the figure is relative to Figure 3A The unbiased example is set at an angle of -2°, thus keeping the incident point centered on DMD 309. To achieve this, the integrating bar 301 is adjusted by a first amount in the third direction 316, and the folding mirror 305 is adjusted by a second amount in the fourth direction 317. The third direction 316 can be opposite to the first direction 314. In addition, the fourth direction 317 can be opposite to the second direction 315 (e.g., a clockwise rotation direction or a positive rotation direction).

[0049] Figures 3A to 3C The angles and angle adjustments shown are illustrative and not restrictive. In practice, specific angles and angle adjustments will depend on several factors, including but not limited to the tilt angle of the micromirrors of the DMD 309, misalignment within the projection system, and the system parameters or performance parameters selected by the user.

[0050] Integrating bar and folding mirror adjustment method

[0051] Figure 4 The illustration depicts an exemplary adjustment or alignment method that can be used in... Figures 3A to 3C The calibration of the portion of the optical system 300 shown in the figure is performed during the calibration process. Figure 4 The adjustment method can be performed automatically (e.g., through a computer program), as will be described in more detail below.

[0052] At operation 401, the adjustment method determines the orientation angle of the DMD micromirror 202, or the deviation of the orientation angle from a desired angle. Alternatively or additionally, 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.

[0053] At operation 402, the adjustment method calculates the appropriate lateral adjustment of the integrating bar 301 and the appropriate rotational adjustment of the folding mirror 305 based on the measured angle of the DMD micromirror 202. The appropriate lateral and rotational adjustments can be amounts that center the third beam 106 on the DMD 309 and in the projection aperture 109. The calculations at operation 402 can be performed using a computer program that receives a single input (the tilt angle of the DMD micromirror 202, or the orientation tilt angle of the DMD micromirror 202 relative to the desired angle) and outputs the lateral adjustment of the integrating bar 301 and the rotational adjustment of the folding mirror 305.

[0054] The calculations for operation 402 can be performed during calibration or pre-executed, and can be stored in a lookup table associated with the projection system 100. In such an implementation, the calibration method can calculate the appropriate mirror angle adjustment by referring to the lookup table.

[0055] Following the calculations in operation 402, in operation 403, the adjustment method actuates the integrator 301 and the folding mirror 305 to implement the calculated adjustment. This actuation can be implemented using a stepper motor, a servo motor, or other suitable adjustment mechanism. For example, the integrator 301 can be coupled to a first track, and the folding mirror 305 can be coupled to a servo motor. The first track and the servo motor can be coupled (e.g., via a mechanical linkage) such that movement of the integrator 301 along the first track causes a corresponding movement of the folding mirror 305 via the servo motor. The integrator 301 can be actuated in a first direction 314 by actuating the first track, thereby placing the integrator 301 in a first position, as calculated in operation 402. In another embodiment, the integrator 301 can be actuated in a third direction 316 by actuating the first track, thereby placing the integrator 301 in a second position, as calculated in operation 402. The folding mirror 305 can be actuated in the second direction 315 by actuating a servo motor, thereby placing the folding mirror 305 in a first position, as calculated in operation 402. In another embodiment, the folding mirror 305 can be actuated in the fourth direction 317 by actuating a servo motor, thereby placing the folding mirror 305 in a second position, as calculated in operation 402. In some examples, actuation is... Figure 1 The actuation is performed under the control of controller 114. In other examples, the actuation is performed under manual control.

[0056] Integrating bar and folding mirror calibration system

[0057] Figure 5 An exemplary portion of the optical system 500 for calibrating the projection system 100 is illustrated. Some components of system 500 are equivalent to... Figures 3A to 3CThe components in the illustrated system 300 are shown. Equivalent components are illustrated using the same reference numerals. System 500 includes an integrating bar 301, a first beam 302, a first lens group 303, a second beam 304, a folding mirror 305, a third beam 306, a second lens group 307, a fourth beam 308, and a DMD 309. In some embodiments, a portion of the optical system 500 also includes a prism 318, such as a total internal reflection (TIR) ​​prism. Additionally, system 500 includes a fifth beam 501, a sixth beam 502, a first projection lens 503, a beam splitter 504, a second projection lens 505, a first screen 506, a third projection lens 507, a second screen 508, and an aperture stop 509. The first projection lens 503, the second projection lens 505, and the first screen 506 can be coupled to the integrating bar 301, the second projection lens 505, and the first screen 506 respectively. Figure 1 The first projection optics 107, the second projection optics 111, and the screen 113 shown in the diagram are identical or similar. The fifth ray 501, represented by long and short dashed lines, is the edge ray of the system. The convergence point of the fifth ray 501 indicates the position of the projected image on the DMD 309. The sixth ray 502, represented by half-dashed lines, is the main ray of the system. The convergence point of the sixth ray 502 indicates the aperture stop 509 or the image of the aperture stop 509.

[0058] Beam splitter 504 separates the fifth beam 501 and the sixth beam 502, causing the light from the fifth beam 501 to converge onto the first screen 506 and the light from the sixth beam 502 to converge onto the second screen 508. Therefore, the image projected by DMD 309 is reflected onto the first screen 506. Specifically, the diffraction pattern projected by DMD 309 can be used to calibrate the projection system 100. The image from aperture stop 509 is projected onto the second screen 508. The first screen 506 can be, for example... Figure 1 The screen 113. Each image can assist in calibrating the projection system 100. For example, a technician calibrating the projection system 100 can view both the diffraction pattern and the actual image of the aperture stop 509 on the second screen 508. For calibration or testing purposes, components including the beam splitter 504 and the second lens 505 can be configured to be inserted into the paths of the fifth beam 501 and the second beam 502. After calibration, the components can be removed from the paths.

[0059] Integrating bar and folding mirror calibration method

[0060] Figure 6 An exemplary calibration method is illustrated, which can be used in... Figure 5 The calibration of the portion of the optical system 500 shown in the figure is performed during the calibration process. Figure 6 The calibration method can be performed manually to set the initial positions of the integrating bar 301 and the folding mirror 305.

[0061] At operation 601, the integrating bar 301 and the folding mirror 305 are moved to the center of their range of motion. For example, the integrating bar 301 may be moved to the center of the first track or the center of its range of motion, as described above. As described above, the folding mirror 305 may be moved to the center of its range of motion, such as 45°.

[0062] At operation 602, install a projection aperture filter, such as... Figure 1 The filter 109 may include an aperture configured to allow a fourth light 108 of a predetermined diffraction order or predetermined illumination angle to pass through. For example, the filter 109 may include a "Fourier portion" or "Fourier lens assembly," which refers to an optical system that performs a spatial Fourier transform on modulated light (e.g., light from DMD 105) by focusing the modulated light onto a Fourier plane. The spatial Fourier transform applied by the Fourier portion converts the propagation angle of each diffraction order of the modulated light into a corresponding spatial location on the Fourier plane. The Fourier portion thus enables the selection of desired diffraction orders and the rejection of undesired diffraction orders by performing spatial filtering at the Fourier plane. For example, the Fourier portion may be configured to allow projection light with an angle of 2° 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.

[0063] At operation 603, the folding reflector 305 is adjusted until the center of the diffraction pattern from DMD 309 is centered on the second screen 508. For example, the fifth light 501 can be a random noise pattern. When the fifth light 501 is projected onto the second screen 508, the observed diffraction pattern (e.g., spatial frequency) is asinc. 2 The diffraction pattern of the fifth beam 501 shifts as the folding mirror 305 is rotated. Once the diffraction pattern is centered, the folding mirror 305 is in its final calibration position. However, the image projected onto the first screen 506 may no longer be fully illuminated. At operation 604, the integrating bar 301 is adjusted until the image of the random noise pattern from the DMD 309 is fully illuminated on the first screen 506. Once the DMD 309 is fully illuminated, the integrating bar 301 is in its final calibration position. The final calibration positions of the integrating bar 301 and the folding mirror 305 are stored in the memory (e.g., a lookup table) of the controller 114 as their initial positions.

[0064] The projection system and calibration method described above can provide a configuration with illumination optics, thereby enabling the adjustment and maintenance of the appropriate illumination angle, the position of the illumination, and the performance of all these operations in an architecture using integrating bars and folded mirrors.

[0065] The systems, methods, and apparatus according to this disclosure may employ any one or more of the following configurations.

[0066] (1) A projection system comprising: a light source configured to emit light in response to image data; an illumination optics system configured to deflect the light, the illumination optics system including an integrating bar and a folding mirror; a digital micromirror device including a plurality of micromirrors, wherein a respective micromirror is configured to reflect the deflected light as on-state light to a predetermined position when the respective micromirror is in an on position, and to reflect the deflected light as off-state light to a light collector when the respective micromirror is in a closed position; and a controller configured to: determine the actual orientation angle of a respective micromirror among the plurality of micromirrors of the digital micromirror device relative to the digital micromirror. The deviation between the target orientation angles of the respective micromirrors in the plurality of micromirrors of the device; based on the deviation between the actual orientation angle and the target orientation angle of the respective micromirrors in the plurality of micromirrors of the digital micromirror device, calculate a first rotational adjustment amount corresponding to the folding mirror and a second lateral adjustment amount corresponding to the integrating bar; rotate the folding mirror by an angle corresponding to the first amount and actuate the integrating bar in a first direction according to the second amount, wherein the second amount is based on the first amount and is configured to change the incident angle of the redirected light on the respective micromirror in response to the deviation and maintain the position of the redirected light on the respective micromirror.

[0067] (2) The projection system according to (1) further includes a first lens group optically arranged between the integrating bar and the folding mirror, and a second lens group optically arranged downstream of the first lens group.

[0068] (3) The projection system according to (2), wherein the second lens group is optically arranged between the folding mirror and the digital micromirror device.

[0069] (4) The projection system according to (2), wherein the second lens group is optically arranged between the first lens group and the folding mirror.

[0070] (5) The projection system according to any one of (1) to (4) further includes a filter between the digital micromirror device and the screen, wherein the filter includes an aperture configured to allow the reflected light of a predetermined diffraction order to pass through.

[0071] (6) The projection system according to any one of (1) to (5), wherein calculating the first amount and the second amount includes matching the deviation with the first rotation adjustment amount and the second lateral adjustment amount using a lookup table stored in the memory of the controller.

[0072] (7) The projection system according to any one of (1) to (6), wherein the lateral dimension of the integral bar is greater than or equal to twice the maximum value of the second quantity.

[0073] (8) The projection system according to any one of (1) to (7) further includes a total internal reflection prism, which is optically disposed between the folding mirror and the digital micromirror device.

[0074] (9) The projection system according to any one of (1) to (8), wherein the first direction is substantially perpendicular to the optical axis of the integrating bar.

[0075] (10) 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 optics system configured to deflect the light, the illumination optics system including an integrating bar and a folded mirror; and a digital micromirror device including a plurality of micromirrors, the plurality of micromirrors being configured to reflect the deflected light as on-state light to a predetermined position when the respective micromirror is in an on position, and to reflect the deflected light as off-state light to a light collector when the respective micromirror is in a closed position, the method comprising: determining the actual orientation angle of a respective micromirror among the plurality of micromirrors of the digital micromirror device relative to the digital micromirror device. The deviation between the target orientation angles of the respective micromirrors in the plurality of micromirrors of the digital micromirror device; based on the deviation between the actual orientation angle and the target orientation angle of the respective micromirrors in the plurality of micromirrors of the digital micromirror device, a first rotational adjustment amount corresponding to the folding mirror and a second lateral adjustment amount corresponding to the integrating bar are calculated; the folding mirror is rotated by an angle corresponding to the first direction and the integrating bar is actuated in the first direction according to the second amount, wherein the second amount is based on the first amount and is configured to change the incident angle of the redirected light on the respective micromirror in response to the deviation and maintain the position of the redirected light on the respective micromirror.

[0076] (11) The method according to (10), wherein the projection system includes a first lens group optically arranged between the integrating bar and the folding mirror, and a second lens group optically arranged downstream of the first lens group.

[0077] (12) According to the method of (11), wherein the second lens group is optically arranged between the folding mirror and the digital micromirror device.

[0078] (13) According to the method of (11), wherein the second lens group is optically arranged between the first lens group and the folding mirror.

[0079] (14) The method according to any one of (10) to (13), wherein the projection system includes a filter between the digital micromirror device and the screen, wherein the filter includes an aperture configured to allow the reflected light of a predetermined diffraction order to pass through.

[0080] (15) The method according to any one of (10) to (14), wherein calculating the first amount and the second amount includes matching the deviation with the first rotational adjustment amount and the second lateral adjustment amount using a lookup table stored in the memory of the controller.

[0081] (16) The method according to any one of (10) to (15), wherein the lateral dimension of the integral bar is greater than or equal to twice the maximum value of the second quantity.

[0082] (17) The method according to any one of (10) to (16), wherein the projection system includes a total internal reflection prism optically disposed between the folding mirror and the digital micromirror device.

[0083] (18) The method according to any one of (10) to (17), wherein the first direction is substantially perpendicular to the optical axis of the integrating bar.

[0084] (19) 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 (10) to (18).

[0085] Regarding the processes, systems, methods, heuristics, etc., described herein, it should be understood that although the steps of such processes, etc., have been described as being performed in a specific ordered order, such processes can be practiced using the described steps performed in a different order than that described herein. Furthermore, it should be understood that certain steps may be performed simultaneously, other steps may be added, or certain steps described herein may 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.

[0086] Therefore, it should be understood that the above description is intended to be illustrative rather than restrictive. Many embodiments and applications beyond the examples provided will become apparent upon reading the above description. The scope should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their eligible equivalents. It is anticipated and desired that the techniques discussed herein will evolve in the future, and the disclosed systems and methods will be incorporated into such future embodiments. In conclusion, it should be understood that modifications and changes are possible with this application.

[0087] All terms used in the claims are intended to be given the broadest reasonable interpretation and common meaning as understood by one skilled in the art described herein, unless expressly indicated otherwise herein. In particular, the use of singular articles such as “a,” “the,” and “said” should be understood to refer to one or more of the indicated elements, unless the claims expressly limit this to the contrary.

[0088] An abstract of this disclosure is provided to allow the reader to quickly determine the nature of the technical disclosure. This abstract is submitted on the premise 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 combined together in various embodiments for the purpose of making this disclosure a coherent whole. The method of this disclosure should not be construed as reflecting an intention to incorporate more features than expressly recited in each claim in the claimed embodiments. Rather, as reflected in the claims, the inventive subject matter lies in fewer than all the features of a single disclosed embodiment. Therefore, the appended claims are thus incorporated into the detailed description, each claim being an independent subject matter claimed.

Claims

1. A projection system, comprising: The light source is configured to emit light in response to image data; An illumination optical system configured to redirect the light, the illumination optical system comprising an integrating bar and a folding mirror; A first lens group is optically arranged between the integrating bar and the folding mirror; A digital micromirror device includes a plurality of micromirrors, wherein a corresponding micromirror is configured to reflect the directed light as on-state light to a predetermined position when the corresponding micromirror is in an open position, and to reflect the directed light as off-state light to a light collector when the corresponding micromirror is in a closed position, wherein the light is projected onto the digital micromirror device at a first position. A second lens group, optically arranged between the folding mirror and the digital micromirror device; and The controller is configured as follows: Receive a value indicating the deviation between the actual orientation angle of a corresponding micromirror among the plurality of micromirrors of the digital micromirror device and the target orientation angle of the corresponding micromirror among the plurality of micromirrors of the digital micromirror device. Based on the deviation between the actual orientation angle and the target orientation angle of the corresponding micromirrors among the plurality of micromirrors of the digital micromirror device, a first rotational adjustment amount corresponding to the folding mirror and a second lateral adjustment amount corresponding to the integrating bar are calculated. The folding mirror is rotated by an angle corresponding to the first quantity using the first actuator, and The integral bar is actuated in the first direction using a second actuator according to a second quantity. The second quantity is based on the first quantity and is configured to change the incident angle of the redirected light on the corresponding micromirror in response to the deviation and to maintain the position of the redirected light on the corresponding micromirror.

2. The projection system according to claim 1, wherein: The second lens group is optically arranged downstream of the first lens group.

3. The projection system according to any one of claims 1 to 2, further comprising a filter between the digital micromirror device and the screen, wherein, The filter includes an aperture configured to allow reflected light of a predetermined diffraction order to pass through.

4. The projection system according to any one of claims 1 to 2, wherein, Calculating the first and second amounts involves matching the deviation with the first rotational adjustment amount and the second lateral adjustment amount using a lookup table stored in the controller's memory.

5. The projection system according to any one of claims 1 to 2, wherein, The lateral dimension of the integral bar is greater than or equal to twice the maximum value of the second quantity.

6. The projection system according to any one of claims 1 to 2 further includes a total internal reflection prism, the total internal reflection prism being optically disposed between the folding mirror and the digital micromirror device.

7. The projection system according to any one of claims 1 to 2, wherein, The first direction is substantially perpendicular to the optical axis of the integrating bar.

8. An automatic calibration method performed by a controller of a projection system, the projection system comprising: The light source is configured to emit light in response to image data; An illumination optical system configured to redirect the light, the illumination optical system comprising an integrating bar and a folding mirror; A first lens group optically arranged between the integrating bar and the folding mirror; A digital micromirror device includes multiple micromirrors, each of which is configured to reflect the directed light as on-state light to a predetermined position when the corresponding micromirror is in an open position, and to reflect the directed light as off-state light to a light collector when the corresponding micromirror is in a closed position, wherein the light is projected onto the digital micromirror device at a first position. The method includes: and a second lens group optically arranged between the folding mirror and the digital micromirror device. Receive a value indicating the deviation between the actual orientation angle of a corresponding micromirror among the plurality of micromirrors of the digital micromirror device and the target orientation angle of the corresponding micromirror among the plurality of micromirrors of the digital micromirror device. Based on the deviation between the actual orientation angle and the target orientation angle of the corresponding micromirrors among the plurality of micromirrors of the digital micromirror device, a first rotational adjustment amount corresponding to the folding mirror and a second lateral adjustment amount corresponding to the integrating bar are calculated. The folding mirror is rotated by an angle corresponding to the first quantity using the first actuator, and The integral bar is actuated in the first direction using a second actuator according to a second quantity. The second quantity is based on the first quantity and is configured to change the incident angle of the redirected light on the corresponding micromirror in response to the deviation and to maintain the position of the redirected light on the corresponding micromirror.

9. The method according to claim 8, wherein, The second lens group is optically arranged downstream of the first lens group.

10. The method according to any one of claims 8 to 9, wherein, The projection system includes a filter between the digital micromirror device and the screen, wherein the filter includes an aperture configured to allow reflected light of a predetermined diffraction order to pass through.

11. The method according to any one of claims 8 to 9, wherein, Calculating the first and second amounts involves matching the deviation with the first rotational adjustment amount and the second lateral adjustment amount using a lookup table stored in the controller's memory.

12. The method according to any one of claims 8 to 9, wherein, The lateral dimension of the integral bar is greater than or equal to twice the maximum value of the second quantity.

13. The method according to any one of claims 8 to 9, wherein, The projection system includes a total internal reflection prism, which is optically positioned between the folding mirror and the digital micromirror device.

14. The method according to any one of claims 8 to 9, wherein, The first direction is substantially perpendicular to the optical axis of the integrating bar.

15. 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 claims 8 to 14.

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