EP4505233A1

EP4505233A1 - Rectangular optical fiber for projection systems

Info

Publication number: EP4505233A1
Application number: EP23720004.3A
Authority: EP
Inventors: Juan Pablo Pertierra; Barret Lippey; John Frederick ARNTSEN; Martin J. Richards
Original assignee: Dolby Laboratories Licensing Corp
Current assignee: Dolby Laboratories Licensing Corp
Priority date: 2022-04-05
Filing date: 2023-04-04
Publication date: 2025-02-12
Also published as: CN119317854A; WO2023196336A1

Abstract

Systems and methods for a rectangular optical fiber within a projection system. One projection system includes a rectangular optical fiber and a first modulator. The rectangular optical fiber is configured to emit a light in response to an image data. The rectangular optical fiber has a first aspect ratio. The first modulator is configured to receive the light from the rectangular optical fiber and to apply a spatially-varying modulation on the light, thereby to steer the light and generate a first steered light. The first modulator has a second aspect ratio.

Description

RECTANGULAR OPTICAL FIBER FOR PROJECTION SYSTEMS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. Provisional application number 63/327,399, filed on 5 April 2022, and from European Patent application number 22166775.1, filed 5 April 2022.

BACKGROUND

1. Field of the Disclosure

[0002] This application relates generally to projection systems and, more specifically, rectangular optical fibers as a light source in projection systems.

2. Description of Related Art

[0003] Digital projection systems typically utilize a light source and an optical system to project an image onto a surface or screen. The light source is typically a laser light source, a light emitting diode, or some other light source. An integrating rod is implemented to homogenize light from the light source. The optical system includes components such as mirrors, lenses, waveguides, optical fibers, beam splitters, diffusers, spatial light modulators (SLMs), phase light modulators (PLMs), and the like. The modulators may be configured as a digital light processor (DLP), a digital micromirror device (DMD), a liquid crystal on silicon (LCOS) modulator, or another appropriate modulator.

BRIEF SUMMARY OF THE DISCLOSURE

[0004] Optical fibers may be used to transmit light from an illumination source to a projector. These fibers are smaller than a typical integrating rod, which have diameters of greater than 2 mm. Optical fibers are commonly circular in construction, and the circular cross-section of the optical fiber core results in a circular output beam. The projector includes an optical system with one or more modulators that spatially-modulate the light provided by the optical fiber. The modulators are typically rectangular, having an aspect ratio and working to construct an image projected by the projector. However, as the beam output by the optical fiber is circular, light is lost through the use of the modulators. Embodiments described herein utilize rectangular optical fibers to improve the optical efficiency of the optical system.

[0005] Various aspects of the present disclosure relate to devices, systems, and methods for implementation of rectangular fibers for use with projectors.

[0006] In one aspect of the present disclosure, there is provided a projection system comprising a rectangular optical fiber and a first modulator. The rectangular optical fiber is configured to emit a light in response to an image data. The rectangular optical fiber has a first aspect ratio. The first modulator is configured to receive the light from the rectangular optical fiber and to apply a spatially-varying modulation on the light, thereby to steer the light and generate a first steered light. The first modulator has a second aspect ratio.

[0007] In another aspect of the present disclosure, there is provided a method for controlling a projection system, the method comprising receiving, with a phase-light modulator, light from a rectangular optical fiber, wherein the rectangular optical fiber is configured to emit a light in response to an image data and having a first aspect ratio, and wherein the phase-light modulator has a second aspect ratio, and steering, with the phase-light modulator, the light at an illumination angle to generate a first steered light.

[0008] In another aspect of the present disclosure, there is provided 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 comprising receiving, with a first modulator, light from a rectangular optical fiber, and steering, with a phase light modulator, the light at an illumination angle to generate a first steered light.

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

DESCRIPTION OF THE DRAWINGS

[0010] These and other more detailed and specific features of various embodiments are more fully disclosed in the following description, reference being had to the accompanying drawings, in which:

[0011] FIG. 1 illustrates a block diagram of an example projection system according to various aspects of the present disclosure;

[0012] FIG. 2A illustrates a plan view of an example spatial light modulator for use with various aspects of the present disclosure;

[0013] FIG. 2B illustrates a cross-sectional view taken along the line II-B of FIG. 2A;

[0014] FIG. 3 illustrates a plan view of an example phase light modulator for use with various aspects of the present disclosure;

[0015] FIG. 4 illustrates a cross-sectional view of another example phase light modulator for use with various aspects of the present disclosure;

[0016] FIG. 5 illustrates an example side view of an optical fiber according to various aspects of the present disclosure;

[0017] FIG. 6A illustrates a cross-section view of a circular portion of the optical fiber of FIG. 5 according to various aspects of the present disclosure; [0018] FIG. 6B illustrates a cross-section view of a rectangular portion of the optical fiber of FIG. 5 according to various aspects of the present disclosure;

[0019] FIG. 7A illustrates an example cross-section view of an array of circular optical fibers according to various aspects of the present disclosure;

[0020] FIG. 7B illustrates an example cross-section view of an array of rectangular optical fibers according to various aspects of the present disclosure; and

[0021] FIG. 8 illustrates an example optical state in an example projection system according to various aspects of the present disclosure.

DETAILED DESCRIPTION

[0022] This disclosure and aspects thereof can 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), and the like. The foregoing summary is intended solely to give a general idea of various aspects of the present disclosure, and does not limit the scope of the disclosure in any way.

[0023] In the following description, numerous details are set forth, such as optical device configurations, timings, operations, and the like, in order to provide an understanding of one or more aspects of the present disclosure. It will be readily apparent to one skilled in the art that these specific details are merely examples and not intended to limit the scope of this application.

[0024] Moreover, while the present disclosure focuses mainly on examples in which the various circuits are used in digital projection systems, it will be understood that this is merely one example of an implementation. It will further be understood that the disclosed systems and methods can be used in any device in which there is a need to project light; for example, cinema, consumer, and other commercial projection systems, heads-up displays, virtual reality displays, and the like.

[0025] Projector Systems

[0026] Optical systems described herein implement rectangular optical fibers to transfer light from a light source to optics within a projector. While a light source and a rectangular optic fiber may be referred to separately, it is to be understood that the rectangular optic fiber is a component of the light source. Thus, reference to only the light source does not exclude the rectangular optic fiber.

[0027] FIG. 1 illustrates an example high contrast projection system 100 according to various aspects of the present disclosure. In particular, FIG. 1 illustrates a projection system 100 which includes a light source 101 (e.g., an optical fiber) configured to emit a first light 102; illumination optics 103 (one example of an illumination optical system in accordance with the present disclosure) configured to receive the first light 102 and redirect or otherwise modify it, thereby to generate a second light 104; a first modulator 105 configured to apply a spatially-varying modulation to the second light 104, thereby to steer the second light 104 and generate a third light 106; first projection optics 107 configured to receive the third light 106 and redirect or otherwise modify it, thereby to generate a fourth light 108; a second modulator 109 configured to modulate the fourth light 108, thereby to generate a fifth light 110; and second projection optics 111 configured to receive the fifth light 110 and project it as a sixth light 112 onto a screen 113. The first modulator 105 may be a phase-based modulator or some other modulator. The second modulator 109 may be an amplitudebased modulator or some other modulator. In some embodiments, the projection system 100 may not include the illumination optics 103; rather, the first light 102 is received directly by the first modulator 105. [0028] The projection system 100 further includes a controller 114 configured to control various components of the projection system 100, such as the light source 101, the first modulator 105, and/or the second modulator 109. In some implementations, the controller 114 may additionally or alternatively control other components of the projection system 100, including but not limited to the illumination optics 103, the first projection optics 107, and/or the second projection optics 111. The controller 114 may be one or more processors such as a central processing unit (CPU) of the projection system 100. The illumination optics 103, the first projection optics 107, and the second projection optics 111 may respectively include one or more optical components such as mirrors, lenses, waveguides, optical fibers, beam splitters, diffusers, and the like. With the exception of the screen 113, the components illustrated in FIG. 1 may be integrated into a housing to provide a projection device. Such a projection device may include additional components such as a memory, input/output ports, communication circuitry, a power supply, and the like. In some embodiments, the light source 101 includes a laser light source, an LED, or some other light emitter which emits light situated outside of the housing of the projection device, in combination with a fiber optic cable configured to deliver the light output by the light emitter to the illumination optics 103 within the housing of the projection device. In other embodiments, both the light emitter and its respective fiber optic cable are located within the housing of the projection device.

[0029] In some implementations, the light output by the light source 101 is coherent light. In some aspects of the present disclosure, the light source 101 may comprise multiple individual 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 the controller 114; 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 successively displayed. Individual elements in the projection system 100, including the illumination optics 103 the first modulator 105, and/or the second modulator 109 may be controlled by the controller 114. The image signal may originate from an external source in a streaming or cloud-based manner, may originate from an internal memory of the projection system 100 such as a hard disk, may originate from a removable medium that is operatively connected to the projection system 100, or combinations thereof.

[0030] The first projection optics 107 and/or the second projection optics 111 may include a filter to mitigate effects caused by internal components of the projection system 100. In some systems, the first modulator 105 (which will be described in more detail below) and/or the second modulator 109 may include a cover glass and cause reflections, device switching may temporarily cause unwanted steering angles, and various components may cause scattering. To counteract this and decrease the floor level of the projection system 100, the filter may be a Fourier (“DC”) filter component configured to block a portion of the third light 106 and/or the fifth light 110. Thus, the filter may increase contrast by reducing the floor level from light near zero angle, which will correspond to such elements as cover-glass reflections, stroke transition states, and the like. This DC block region may be actively used to prevent certain light from reaching the screen 113. In some aspects of the present disclosure, the filter prevents the undesired light from reaching the screen 113 by steering said light to a light dump located outside the active image area, in response to control from the controller 114.

[0031] Although FIG. 1 illustrates a generally linear optical path, in practice the optical path is generally more complex. For example, in the projection system 100, the second light 104 from the illumination optics 103 is steered to the first modulator 105 at an oblique angle, and the fourth light 108 steered from the first projection optics 107 is steered to the second modulator 109 at an oblique angle. In order to ensure that the image on the screen 113 has an acceptable clarity and contrast ratio, the illumination optics 103 may be designed and/or controlled to ensure that the angle of incidence on the first modulator 105 is correct, while maintaining the position of the second light 104 centered on the first modulator 105. The first modulator 105 and/or the first projection optics

107 may be designed and/or controlled to ensure that the angle of incidence on the second modulator 109 is correct, while maintaining the position of the fourth light 108 centered on the second modulator 109.

Spatial Light Modulator

[0032] In some implementations, the first modulator 105 and/or the second modulator 109 is a digital micromirror device (DMD) composed of a plurality of mirrors used to adjust the angle of incidence of light (e.g., the fourth light 108). To illustrate the effects of the angle of incidence and the DMD mirrors, FIGS. 2A-2B show an example DMD 200 in accordance with various aspects of the present disclosure. In particular, FIG. 2A illustrates a plan view of the DMD 200, and FIG. 2B illustrates partial cross-sectional view of the DMD 200 taken along line II-B illustrated in FIG. 2A. 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). Each micromirror 202 may correspond to one pixel of the eventual projection image, and may be configured to tilt about a rotation axis 208, shown for one particular subset of the micromirrors 202, by electrostatic or other type of actuation. The individual micromirrors 202 have a width 212 and are arranged with gaps of width 210 therebetween. The micromirrors 202 may be formed of or coated with any highly reflective material, such as aluminum or silver, to thereby specularly reflect light. The gaps between the micromirrors 202 may be absorptive, such that input light which enters a gap is absorbed by the substrate 204.

[0033] While FIG. 2A expressly shows only some representative micromirrors 202, in practice the DMD 200 may include many more individual micromirrors in a number equal to a resolution of the projection system 100. In some examples, the resolution may be 2K (2048x1080), 4K (4096x2160), 1080p (1920x1080), consumer 4K (3840x2160), and the like. Moreover, in some examples the micromirrors 202 may be rectangular and arranged in the rectangular array; hexagonal and arranged in a hexagonal array, and the like. Moreover, while FIG. 2A illustrates the rotation axis 208 extending in an oblique direction, in some implementations the rotation axis 208 may extend vertically or horizontally.

[0034] As can be seen in FIG. 2B, each micromirror 202 may be connected to the substrate 204 by a yoke 214, which is rotatably connected to the micromirror 202. The substrate 204 includes a plurality of electrodes 216. While only two electrodes 216 per micromirror 202 are visible in the cross-sectional view of FIG. 2B, each micromirror 202 may in practice include additional electrodes. While not particularly illustrated in FIG. 2B, the DMD 200 may further include spacer layers, support layers, hinge components to control the height or orientation of the micromirror 202, and the like. The substrate 204 may include electronic circuitry associated with the DMD 200, such as complementary metal-oxide semiconductor (CMOS) transistors, memory elements, and the like.

[0035] Depending on the particular operation and control of the electrodes 216, the individual micromirrors 202 may be switched between an “on” position, an “off’ position, and an unactuated or neutral position. If a micromirror 202 is in the on position, it is actuated to an angle of (for example ) -12° (that is, rotated counterclockwise by 12° relative to the neutral position) to specularly reflect input light 206 into on-state light 218. If a micromirror 202 is in the off position, it is actuated to an angle of (for example) +12° (that is, rotated clockwise by 12° relative to the neutral position) to specularly reflect the input light 206 into off-state light 220. The off-state light 220 may be directed toward a light dump that absorbs the off-state light 220. In some instances, a micromirror 202 may be unactuated and lie parallel to the substrate 204. The particular angles illustrated in FIGS. 2A-2B and described here are merely examples and not limiting. In some implementations, the on- and off-position angles may be between ±11 and ±13 degrees (inclusive), respectively. Phase Light Modulator

[0036] Rather than a spatial light modulator, the first modulator 105 and/or the second modulator

109 may be a phase light modulator. A phase light modulator (PLM) imparts a spatially-varying phase modulation to the light, and redirects the modulated light toward the respective projection optics. The phase light modulator may be a reflective type, in which the phase light modulator reflects incident light with a spatially-varying phase; alternatively, the phase light modulator may be of a transmissive type, in which the phase light modulator imparts a spatially-varying phase to light as it passes through the phase light modulator. In some aspects of the present disclosure, the phase light modulator has a liquid crystal on silicon (LCOS) architecture. In other aspects of the present disclosure, the phase light modulator has a micro-electromechanical system (MEMS) architecture such as a DMD.

[0037] FIG. 3 illustrates one example of the first modulator 105 and/or the second modulator 109, implemented as a reflective LCOS PLM 300 and shown in a partial cross-sectional view. As illustrated in FIG. 3, the PLM 300 includes a silicon backplane 310, a first electrode layer 320, a second electrode layer 330, a liquid crystal layer 340, a cover glass 350, and spacers 360. The silicon backplane 310 includes electronic circuitry associated with the PLM 300, such as CMOS transistors and the like. The first electrode layer 320 includes an array of reflective elements 321 disposed in a transparent matrix 322. The reflective elements 321 may be formed of any highly optically reflective material, such as aluminum or silver. The transparent matrix 322 may be formed of any highly optically transmissive material, such as a transparent oxide. The second electrode layer 330 may be formed of any optically transparent electrically conductive material, such as a thin film of indium tin oxide (ITO). The second electrode layer 330 may be provided as a common electrode corresponding to a plurality of the reflective elements 321 of the first electrode layer 320. In such a configuration, each of the plurality of the reflective elements 321 will couple to the second electrode layer 330 via a respective electric field, thus dividing the PLM 300 into an array of pixel elements.

Thus, individual ones (or subsets) of the plurality of the reflective elements 321 may be addressed via the electronic circuitry disposed in the silicon backplane 310, thereby to modify the state of the corresponding reflective element 321.

[0038] The liquid crystal layer 340 is disposed between the first electrode layer 320 and the second electrode layer 330, and includes a plurality of liquid crystals 341. The liquid crystals 341 are particles which exist in a phase intermediate a solid and a liquid; in other words, the liquid crystals 341 exhibit a degree of directional order, but not positional order. The direction in which the liquid crystals 341 tend to point is referred to as the “director.” The liquid crystal layer 340 modifies incident light entering from the cover glass 350 based on the birefringence An of the liquid crystals 341 , which may be expressed as the difference between the refractive index in a direction parallel to the director and the refractive index in a direction perpendicular to the director. From this, the maximum optical path difference may be expressed as the birefringence multiplied by the thickness of the liquid crystal layer 340. This thickness is set by the spacer 360, which seals the PLM 300 and ensures a set distance between the cover glass 350 and the silicon backplane 310. The liquid crystals 341 generally orient themselves along electric field lines between the first electrode layer 320 and the second electrode layer 330. As illustrated in FIG. 3, the liquid crystals near the center of the PLM 300 are oriented in this manner, whereas the liquid crystals 341 near the periphery of the PLM 300 are substantially non-oriented in the absence of electric field lines. By addressing individual ones of the plurality of reflective elements 321 via a phase-drive signal, the orientation of the liquid crystals 341 may be determined on a pixel -by -pixel basis.

[0039] FIG. 4 illustrates another example of the first modulator 105 and/or the second modulator 109, implemented as a DMD PLM 400 and shown in a partial cross-sectional view. As illustrated in FIG. 4, the PLM 400 includes a backplane 410 and a plurality of controllable reflective elements as pixel elements, each of which includes a yoke 421, a mirror plate 422, and a pair of electrodes 430.

While only two electrodes 430 are visible in the cross-sectional view of FIG. 4, each reflective element may in practice include additional electrodes. While not particularly illustrated in FIG. 4, the PLM 400 may further include spacer layers, support layers, hinge components to control the height or orientation of the mirror plate 422, and the like. The backplane 410 includes electronic circuitry associated with the PLM 400, such as CMOS transistors, a memory array, and the like.

[0040] The yoke 421 may be formed of or include an electrically conductive material so as to permit a biasing voltage to be applied to the mirror plate 422. The mirror plate 422 may be formed of any highly reflective material, such as aluminum or silver. The electrodes 430 are configured to receive a first voltage and a second voltage, respectively, and may be individually addressable. Depending on the values of a voltage on the electrodes 430 and a voltage (for example, the biasing voltage) on the mirror plate 422, a potential difference exists between the mirror plate 422 and the electrodes 430, which creates an electrostatic force that operates on the mirror plate 422. The yoke 421 is configured to allow vertical movement of the mirror plate 422 in response to the electrostatic force. The equilibrium position of the mirror plate 422, which occurs when the electrostatic force and a spring-like force of the yoke 421 are equal, determines the optical path length of light reflected from the upper surface of the mirror plate 422. Thus, individual ones of the plurality of controllable reflective elements are controlled to provide a number (as illustrated, three) of discrete heights and thus a number of discrete phase configurations or phase states. As illustrated, each of the phase states has a flat profile. In some aspects of the present disclosure, the electrodes 430 may be provided with different voltages from one another so as to impart a tilt to the mirror plate 422. Such tilt may be utilized with a light dump of the type described above.

[0041] The PLM 400 may be capable of high switching speeds, such that the PLM 400 switches from one phase state on the order of tens of ps, for example. In order to provide for a full cycle of phase control, the total optical path difference between a state where the mirror plate 422 is at its highest point and a state whether the mirror plate 422 is at its lowest point should be approximately equal to the wavelength X of incident light. Thus, the height range between the highest point and the lowest point should be approximately equal to X/2.

Optic Fiber

[0042] As previously stated, the light source 101 may include both a light emitter and an optical fiber. FIG. 5 illustrates one example of an optical fiber 500 for use with the light source 101. The optical fiber 500 includes a circular portion 510 and a rectangular portion 540. The circular portion 510 and the rectangular portion 540 are coupled together via a splicing portion 530. The circular portion 510 includes a circular outer cladding 515, a circular inner cladding 525, and a circular core 520. The rectangular portion 540 includes a rectangular outer cladding 555, a rectangular inner cladding 565, and a rectangular core 560. In some embodiments, the rectangular portion 540 does not include the rectangular inner cladding 565.

[0043] Light from a light emitter travels through the circular core 520, reflecting off the circular inner cladding 525 as it travels. The light then travels through the splicing portion 530 into the rectangular core 560. Light exits the optical fiber 500 via a projecting end 550. Any light that may escape either inner cladding (due to mis-adjustment, too much fiber bending, or similar circumstances) is reflected by the respective outer cladding. In some embodiments, the entire length of the optical fiber 500 has a rectangular cross-section (e.g., consists only of the rectangular portion 540), rather than splicing the rectangular portion 540 to the circular portion 510.

[0044] FIG. 6A illustrates a partial cross-sectional view of the circular portion 510 taken along line V-A illustrated in FIG. 5. As seen in FIG. 6A, the circular portion 510 has a circular cross-section with a diameter 600. The diameter 600 is less than 2 mm. FIG. 6B illustrates a partial cross-sectional view of the rectangular portion 540 taken along line V-B illustrated in FIG. 5. The rectangular portion 540 includes a width 605 and a length 610, together forming a rectangular aspect ratio.

[0045] In some embodiments, rather than splicing the rectangular portion 540 to the circular portion 510, the rectangular optical fiber is instead formed by creating an array of circular optical fibers. FIG. 7A illustrates an example optical fiber 700 formed by a plurality of circular optical fibers 715. The plurality of circular optical fibers 715 form an array having a width 705 and a length 710. In the illustrated embodiment, the optical fiber 700 has an aspect ratio of a 16 by 9 array of circular optical fibers 715. However, the optical fiber 700 may have a different aspect ratio. For example, the optical fiber 700 may have an aspect ratio of 1. In some examples, one axis of the optical fiber 700 is stretched optically to match an aspect ratio of a downstream modulator (such as the first modulator 105).

[0046] In some embodiments, rather than a being formed of an array of circular optical fibers, the optical fiber 700 may be formed of a plurality of rectangular optical fibers. FIG. 7B illustrates an example optical fiber 750 formed by a plurality of rectangular optical fibers 765. The plurality of rectangular optical fibers 765 form an array having a width 755 and a length 760. In the illustrated embodiment, the optical fiber 750 has an aspect ratio of a 16 by 9 array of rectangular optical fibers 765. The aspect ratio of the optical fiber 750 may match the aspect ratio of the first modulator 105. While some embodiments use arrays of optical fibers to achieve the desired aspect ratio, low- etendue optical systems may benefit from the single optical fiber 500 to achieve small, bright spots in projected images.

Example Optical System

[0047] One example implementation of the present disclosure provides an optical system having a first light-steering modulator, such as a PLM or an SLM, that receives light from a rectangular optical fiber. FIG. 8 illustrates an example optical state of a partial optical system 800 in accordance with the present disclosure. The partial optical system 800 may be an example, at least in part, of the projection system 100.

[0048] In particular, FIG. 8 illustrates a light source 801, a first light 802, illumination optics 803, a second light 804, a first modulator 805, a third light 806, first projection optics 807, a fourth light 808, a second modulator 809, a fifth light 810, second projection optics 811, a sixth light 812, and an optical output 813. Various elements illustrated in FIG. 8 may correspond to various elements (or parts of various elements) illustrated in FIG. 1. In some implementations, the first modulator 805 is a PLM device, and the second modulator 809 is a SLM device. In some examples, the second modulator 809 is attached to a prism 821 , such as a prism that combines light in the RGB color domain to white light.

[0049] The light source 801 is an output of a rectangular optical fiber, such as the projecting end 550 described with respect to FIG. 5. Accordingly, the first light 802 has an aspect ratio equal to the aspect ratio of the rectangular optical fiber (e.g., the light source 801).

[0050] In the implementation illustrated in FIG. 8, the illumination optics 803 includes a first diffuser 814, a first lens 815, and a second lens 816. The first diffuser 814 may alter the first light 802 and create a desired point-spread-function (PSF) for the second light 804 received by the first modulator 805. In some implementations, the first diffuser 814 is synchronized with the first modulator 805 and/or the second modulator 809. Additionally, in some examples, the first diffuser 814 is spinning. In other examples, the first diffuser 814 is stationary. In some implementations, the first diffuser 814 may blur the image projected by the light source 801, removing coherence from the first light 802 preventing the need for precise registration requirements. [0051] Although shown as including two lenses, the illumination optics 803 may be composed of any number of lenses to direct the first light 802 to the first modulator 805 at a predetermined illumination angle 0. Moreover, while each individual lens is separately illustrated, the individual lenses may be cemented to one another. Additionally, each lens group may be composed of any type of lenses, such as concave lenses, collimator lenses, negative meniscus lenses, and positive meniscus lenses. In some implementations, the illumination optics 803 includes a cylindrical lens to modify the aspect ratio of the first light 802 projected by the light source 801. In other implementations, the partial optical system 800 does not include the illumination optics 803 such that the first light 802 directly contacts the first modulator 805. The aspect ratio of the first light 802 may be the same as the aspect ratio of the first modulator 805 (e.g., a second aspect ratio).

[0052] While the aspect ratio of the light source 801 may match the aspect ratio of the first modulator 805, in many implementations, the second light 804 (or the first light 802) impacts the first modulator 805 at a predetermined illumination angle. Accordingly, the first modulator 805 is tilted (e.g., not perpendicular) from the perspective of the light source 801. To adjust for this “tilt”, the aspect ratio of the first modulator 805 may be selected to equal the aspect ratio of the “tilted” first modulator 805. For example, the first modulator 805 rests on an axis not perpendicular to an axis defined by the first light 802. The aspect ratio of the first modulator 805, from the perspective of the light source 801, is a tilted aspect ratio. The aspect ratio of the light source 801 is equal to the tilted aspect ratio of the first modulator 805 such that the entire area of the first modulator 805 receives light.

[0053] In the implementation illustrated in FIG. 8, the first projection optics 807 (e.g., imaging relay optics) includes a third lens 818, a first filter 819, and a fourth lens 820. In other implementations, the first projection optics 807 may not include the first filter 819. The first filter 819 may include an aperture configured to pass a predetermined diffractive order, or predetermined illumination angle, of the third light 806. For example, the first filter 819 may include a “Fourier part” or “Fourier lens assembly” which refers to an optical system that spatially Fourier transforms modulated light (e.g., light from the first modulator 805) by focusing the modulated light onto a Fourier plane. The spatial Fourier transform imposed by the Fourier part converts the propagation angle of each diffraction order of the modulated light to a corresponding spatial position on the Fourier plane. The Fourier part thereby enables selection of desired diffraction orders, and rejection of undesired diffraction orders, by spatial filtering at the Fourier plane.

[0054] Although shown as including two lenses, the first projection optics 807 may be composed of any number of lenses to direct the fourth light 808 to the second modulator 809 at a second predetermined illumination angle cp. Moreover, while each individual lens is separately illustrated, the individual lenses may be cemented to one another. In some examples, the third lens 818 and the fourth lens 820 may be composed of several lenses forming a lens group. Additionally, each lens or lens group may be composed of any type of lenses, such as concave lenses, negative meniscus lenses, and positive meniscus lenses.

[0055] In the implementation of FIG. 8, the second projection optics 811 includes a fifth lens 823, a sixth lens 824, a second filter 825, a seventh lens 826, and an eighth lens 827. In other implementations, the second projection optics 811 may not include the second filter 825. The second filter 825 may be functionally similar to the first filter 819 (e.g., including a “Fourier part”). In some implementations, the second filter 825 is configured to improve the black level of the second modulator 809. In some implementations, the optical system 800 includes a window actuator 822 situated optically between the second modulator 809 and the second projection optics 811. The window actuator 822 is configured to upscale the image reflected by the second modulator 809 (e.g., the fifth light 810). For example, the window actuator 822 may upscale the image reflected by the second modulator 809 from a 720p image to a 1080p image, a 1080p image to a 2K image, a 2K image to a 4K image, or the like.

[0056] In some implementations, the optical system 800 includes a second diffuser 817. The second diffuser 817 may add angular diversity to the third light 806 after the image is reconstructed, reducing the impact of dust and other obstructions within the optical system 800. In some implementations, the second diffuser 817 is synchronized with the first modulator 805 and/or the second modulator 809. Additionally, in some examples, the second diffuser 817 is spinning. In other examples, the second diffuser 817 is stationary.

[0057] The image output by the light source 801 is constructed on a plane (e.g., a reconstructed image plane) between the first modulator 805 and the second modulator 809. The angle between the reconstructed image formed on the reconstructed image plane and the optical axis is controlled by the first illumination angle 0. The reconstructed image from the first modulator 805 is then imaged onto the second modulator 809, but the plane of the second modulator 809 is tilted with respect to the reconstructed image plane. To account for this tilt in the reconstructed image, in some implementation, the first illumination angle 0 is selected to satisfy the Scheimpflug criteria of the second modulator 809. As previously described, when the second modulator 809 is a DMD, the micromirrors 202 are tilted to approximately 12°. In such an implementation, the first illumination angle 0 is selected to be approximately 24°. In implementations where the second modulator 809 is a DLP, the second modulator has diagonally (i.e., 45° azimuth tilt) tilted mirrors. In this scenario, the first illumination angle 0 at the first modulator 805 is also chosen to be 45°. By selecting the first illumination angle 0 to satisfy the Scheimpflug criteria, the reconstructed image is completely in focus on the second modulator 809. [0058] In some embodiments, distortion of the reconstructed image results in the image having a trapezoidal shape on the second modulator 809. Such distortion prevents efficient fill of the second modulator 809, as the trapezoidal shape does not fill the rectangular shape of the second modulator 809. Accordingly, the first illumination angle 0 may be selected such that the reconstructed image provided by the first modulator 805 is approximately rectangular on the second modulator 809, achieving improved optical efficiency.

[0059] To achieve or adjust the first illumination angle 0, the position of the light source 801, the illumination optics 803, the first modulator 805, the first projection optics 807, and the second modulator 809 may be set during construction of the optical system 800. In some implementations, the positions of the light source 801, the illumination optics 803, and the first projection optics 807 may be set or adjusted to alter the first illumination angle 0 using a respective track and actuator controlled by the controller 114. In some implementations, the reflection characteristics of the illumination optics 803 and the first projection optics 807 are electrically controlled by the controller 114 to alter the first illumination angle 0.

[0060] In some embodiments, the optical system 800 represents only a single color channel of the projection system 100. Accordingly, each color channel in the projection system 100 may have its own optical system configured similar to the optical system 800, each having their own respective first modulator 105 and second modulator 109. Each color channel may be combined following their respective optical output 813 prior to being projected on the screen 113. The optical output 813 may be a 3-channel prism, such as that found in U.S. Patent No. 10,197,902, “High Contrast Discrete Input Prism for Image Projectors,” which is incorporated herein by reference in its entirety. [0061] The above projection systems may provide for an optical configuration utilizing a rectangular optical fiber for providing light to a modulator having the same aspect ratios, improving the optical efficiency of the system and increasing an amount of light reflected by the modulator.

[0062] Systems, methods, and devices in accordance with the present disclosure may take any one or more of the following configurations.

[0063] (1) A projection system comprising: a rectangular optical fiber configured to emit a light in response to an image data, the rectangular optical fiber having a first aspect ratio; and a first modulator configured to receive the light from the rectangular optical fiber and to apply a spatially- varying modulation on the light, thereby to steer the light and generate a first steered light, the first modulator having a second aspect ratio.

[0064] (2) The projection system according to (1), wherein the first aspect ratio is different than the second aspect ratio.

[0065] (3) The projection system according to (1) or (2), further comprising a first projection optics disposed between the rectangular optical fiber and the first modulator, the first projection optics configured to convert the aspect ratio of the light emitted by the rectangular optical fiber from the first aspect ratio to the second aspect ratio.

[0066] (4) The projection system according to (3), wherein the first projection optics includes a cylindrical lens.

[0067] (5) The projection system according to any one of (1) to (4), wherein the first aspect ratio is the same as the second aspect ratio.

[0068] (6) The projection system according to any one of (1) to (5), wherein the rectangular optical fiber includes: a first optical fiber portion having a circular shape; and a second optical fiber portion having a rectangular shape, the second optical fiber portion being spliced onto an end of the first optical fiber portion.

[0069] (7) The projection system according to any one of (1) to (6), wherein the rectangular optical fiber includes a plurality of optical fiber portions configured as a rectangular array.

[0070] (8) The projection system according to any one of (1) to (7), further comprising: a second modulator configured to receive the first steered light and to apply a spatially-varying modulation on the first steered light, thereby to generate a second steered light, wherein an image included in the light emitted by the rectangular optical fiber is constructed optically between the first modulator and the second modulator.

[0071] (9) The projection system according to (8), wherein the first modulator applies a spatially- varying phase modulation on the light, and wherein the second modulator applies a spatially-varying amplitude modulation on the first steered light.

[0072] (10) The projection system according to any one of (1) to (9), wherein the rectangular optical fiber is configured to emit light on a first axis, wherein the first modulator is situated on a plane defined by a second axis, and wherein the second axis is not perpendicular to the first axis such that the first modulator is tilted respective to the rectangular optical fiber.

[0073] (11) The projection system according to (10), wherein the second aspect ratio of the first modulator from the perspective of the rectangular optical fiber is a tilted aspect ratio, and wherein the first aspect ratio of the rectangular optical fiber is equal to the tilted aspect ratio.

[0074] (12) A method for controlling a projection system, the method comprising: receiving, with a phase-light modulator, light from a rectangular optical fiber, wherein the rectangular optical fiber is configured to emit a light in response to an image data and having a first aspect ratio, and wherein the phase-light modulator has a second aspect ratio, and steering, with the phase-light modulator, the light at an illumination angle to generate a first steered light.

[0075] (13) The method according to (12), wherein the first aspect ratio is different than the second aspect ratio.

[0076] (14) The method according to (12) or (13), further comprising: converting, with first projection optics disposed between the rectangular optical fiber and the phase-light modulator, the aspect ratio of the light emitted by the rectangular optical fiber from the first aspect ratio to the second aspect ratio.

[0077] (15) The method according to (14), wherein the first projection optics includes a cylindrical lens.

[0078] (16) The method according to any one of (12) to (15), wherein the rectangular optical fiber includes: a first optical fiber portion having a circular shape; and a second optical fiber portion have a rectangular shape, the second optical fiber portion being spliced onto an end of the first optical fiber portion.

[0079] (17) The method according to any one of (12) to (16), further comprising: receiving, with a spatial-light modulator, the first steered light, and steering, with the spatial-light modulator, the first steered light to generate a second steered light, wherein an image included in the light emitted by the rectangular optical fiber is constructed optically between the phase-light modulator and the spatial- light modulator.

[0080] (18) The method according to (17), further comprising: applying, with the phase-light modulator, a spatially-varying phase modulation on the light, and applying, with the spatial-light modulator, a spatially-varying amplitude modulation on the first steered light. [0081] (19) The method according to any one of (12) to (18), wherein the rectangular optical fiber is configured to emit light on a first axis, wherein the phase-light modulator is situated on a second axis, wherein the second axis is not perpendicular to the first axis such that the phase-light modulator is tilted respective to the rectangular optical fiber and such that the second aspect ratio of the phase-light modulator from the perspective of the rectangular optical fiber is a tilted aspect ratio, and wherein the first aspect ratio of the rectangular optical fiber is equal to the tilted aspect ratio.

[0082] (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 comprising the method according to any one of (12) to (19).

[0083] With regard to the processes, systems, methods, heuristics, etc. described herein, it should be understood that, although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of processes herein are provided for the purpose of illustrating certain embodiments, and should in no way be construed so as to limit the claims.

[0084] Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the application is capable of modification and variation.

[0085] All terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those knowledgeable in the technologies described herein unless an explicit indication to the contrary in made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.

The 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. In addition, 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 the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.

Claims

1. A projection system, comprising: a rectangular optical fiber configured to emit a light in response to an image data, the rectangular optical fiber having a first aspect ratio; and a first modulator configured to receive the light from the rectangular optical fiber and to apply a spatially-varying modulation on the light, thereby to steer the light and generate a first steered light, the first modulator having a second aspect ratio.

2. The projection system according to claim 1, wherein the first aspect ratio is different than the second aspect ratio.

3. The projection system according to claim 1 or 2, further comprising a first projection optics disposed between the rectangular optical fiber and the first modulator, the first projection optics configured to convert the aspect ratio of the light emitted by the rectangular optical fiber from the first aspect ratio to the second aspect ratio.

4. The projection system according to any one of claim 1 to claim 3, wherein the first aspect ratio is the same as the second aspect ratio.

5. The projection system according to any one of claim 1 to claim 4, wherein the rectangular optical fiber includes: a first optical fiber portion having a circular shape; and a second optical fiber portion having a rectangular shape, the second optical fiber portion being spliced onto an end of the first optical fiber portion.

6. The projection system according to any one of claim 1 to claim 5, wherein the rectangular optical fiber includes a plurality of optical fiber portions configured as a rectangular array.

7. The projection system according to any one of claim 1 to claim 6, further comprising: a second modulator configured to receive the first steered light and to apply a spatially- varying modulation on the first steered light, thereby to generate a second steered light, wherein an image included in the light emitted by the rectangular optical fiber is constructed optically between the first modulator and the second modulator.

8. The projection system according to any one of claim 1 to claim 7, wherein the rectangular optical fiber is configured to emit light on a first axis, wherein the first modulator is situated on a second axis, and wherein the second axis is not perpendicular to the first axis such that the first modulator is tilted respective to the rectangular optical fiber.

9. The projection system according to claim 8, wherein the second aspect ratio of the first modulator from the perspective of the rectangular optical fiber is a tilted aspect ratio, and wherein the first aspect ratio of the rectangular optical fiber is equal to the tilted aspect ratio.

10. A method for controlling a projection system, the method comprising: receiving, with a phase-light modulator, light from a rectangular optical fiber, wherein the rectangular optical fiber is configured to emit a light in response to an image data and having a first aspect ratio, and wherein the phase-light modulator has a second aspect ratio, and steering, with the phase-light modulator, the light at an illumination angle to generate a first steered light.

11. The method according to claim 10, wherein the first aspect ratio is different than the second aspect ratio.

12. The method according to claim 10 or 11, further comprising: converting, with first projection optics disposed between the rectangular optical fiber and the phase-light modulator, the aspect ratio of the light emitted by the rectangular optical fiber from the first aspect ratio to the second aspect ratio.

13. The method according to any one of claim 10 to claim 12, wherein the rectangular optical fiber includes: a first optical fiber portion having a circular shape; and a second optical fiber portion having a rectangular shape, the second optical fiber portion being spliced onto an end of the first optical fiber portion.

14. The method according to any one of claim 10 to claim 13, wherein the rectangular optical fiber is configured to emit light on a first axis, wherein the phase-light modulator is situated on a second axis, wherein the second axis is not perpendicular to the first axis such that the phaselight modulator is tilted respective to the rectangular optical fiber and such that the second aspect ratio of the phase-light modulator from the perspective of the rectangular optical fiber is a tilted aspect ratio, and wherein the first aspect ratio of the rectangular optical fiber is equal to the tilted aspect ratio.

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 comprising the method according to any one of claim 10 to claim 14.