Patent Description:
Digital projection systems typically utilize a light source and an optical system to project an image onto a surface or screen. The optical system includes components such as mirrors, lenses, waveguides, optical fibers, beam splitters, diffusers, spatial light modulator (SLMs), and the like. Some emerging imaging technologies use beam steering technology, which is achieved with phase modulation, tilting mirror devices, rising mirror/piston devices, and the like. In such a system, the quality of the output image is dependent on the etendue of the light, which is a measure of the effective spatial and angular size of the light source.

<CIT> discloses a light-emitting device and a projection system, comprising: a laser array light source which comprises a non-light-emitting region and a light-emitting region consisting of a plurality of laser elements; a reflective light-condensing system which comprises a light-condensing region and a non-light-condensing region, wherein the light-condensing region is used for focusing and reflecting emergent light of the laser array light source; and a light-collecting system used for collecting and emitting the emergent light from the reflective light-condensing system. <CIT> discloses that the light-collecting system, the non-light-emitting region and the non-light-condensing region are located in the same straight line parallel to a light axis of the emergent light of the laser array light source, and the light-collecting system passes through the non-light-emitting region and/or the non-light-condensing region.

<CIT> discloses a projection system including a base signal source, a highlight signal source, a base/highlight destination, and a shared optical element. <CIT> discloses that a base signal provided by the base source and a highlight signal provided by the highlight source are combined by the shared optical element.

<CIT> further discloses that in a particular embodiment, the base signal source and the highlight signal source each include a light source, a spatial light modulator, and optics, and the base/highlight destination includes optics and a spatial light modulator.

<CIT> further discloses that in a more particular embodiment, the base signal source and the highlight source provide spatially modulated lightfields to the shared optical element. <CIT> further discloses that in another particular embodiment, the base signal and the highlight signal are modulated by the spatial light modulator of the base/highlight destination after being combined.

<CIT> discloses a device, system and method for modulating light using a phase light modulator (PLM) and a spatial light modulator (SLM). <CIT> discloses that a device determines a target-destination wave, representative of an image, to be formed at an image plane of the PLM using image data, defining the image for projection, and a random seeding of spatial values of a spatially varying phase of the target-destination wave at the image plane, the image plane located between the PLM and SLM, the SLM and PLM arranged such that light reflected from the PLM illuminates the SLM. <CIT> discloses that the device determines a target-source wave to be formed at the PLM, based on: a free space transfer function between the PLM and the image plane; and the target-destination wave, and that the device determines, from the target-source wave, a phase map for controlling the PLM to form the image, and that the device controls the PLM using the phase map.

<CIT> discloses a light-emitting device and a related light source system, with the light-emitting device comprising a laser light source and a light collecting system. <CIT> discloses that the laser light source comprises a first laser array and a second laser array for respectively generating a first light and a second light with different wavelength ranges. <CIT> discloses that the light collecting system is used for collecting the light emitted from the laser light source arrays. <CIT> discloses that the ratio of the divergence angle of the collected second light to that of the first light is less than or equal to a predetermined value, which predetermined value is <NUM>.

Various aspects of the present disclosure relate to circuits, systems, and methods for projection display using both high and low etendue components of a light source. Embodiments of the invention are set out in the dependent claims.

In one exemplary aspect of the present disclosure, there is provided a projection system for etendue utilization, the projection system comprising: a light source configured to emit a light, the light including a first etendue component and a second etendue component, a first projection optics configured to project a first image on a screen, a second projection optics configured to project a second image on the screen, and an etendue splitter component. The etendue splitter component is configured to: receive the light from the light source, extract, from the light, the first etendue component and the second etendue component, provide the first etendue component to the first projection optics, and provide the second etendue component to the second projection optics.

In another exemplary aspect of the present disclosure, there is a provided a projection system for etendue utilization, the projection system comprising: a light source configured to emit a first light having a first amount of etendue, a projection device configured to project a first image on a screen, and at least one optical component. The at least one optical component is configured to: receive the first light, extract a second light having a second amount of etendue lower than the first amount of etendue, and provide the second light to the projection device.

In another exemplary aspect of the present disclosure, there is provided a projection system for etendue utilization, the projection system comprising: a light source configured to emit a first light having a first etendue, and an etendue component, wherein the etendue component is configured to receive the first light and extract, from the first light, a second light having a second etendue and a third light having a third etendue, wherein the second etendue is lower than the first etendue, and wherein the first etendue is lower than the third etendue. The projection system comprises: a first light modulator configured to receive the second light, to modulate the second light in a manner associated with a first image, and to output the modulated second light, and a second light modulator configured to receive the modulated second light from the first light modulator and to receive the third light from the etendue component, to modulate the third light and additionally modulate the modulated second light in a manner associated with the first image, and to output the modulated third light and additionally modulated second light.

In another exemplary aspect of the present disclosure, there is provided a method for etendue utilization within a projection system, the projection system including a light source configured to emit a light, the light including a first etendue component and a second etendue component, wherein the first etendue component has a lower etendue than the second etendue component, a first projection optics configured to project a first image on a screen, a second projection optics configured to project a second image on the screen, and an etendue splitter component, the method comprising: receiving the light from the light source, extracting, from the light, the first etendue component and the second etendue component, providing the first etendue component to the first projection optics, and providing the second etendue component to the second projection optics.

In another exemplary 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 including a light source configured to emit a light, the light including a first etendue component and a second etendue component, wherein the first etendue component has a lower etendue than the second etendue component, a first projection optics configured to project a first image on a screen, a second projection optics configured to project a second image on the screen, and an etendue splitter component, cause the projection system to perform operations comprising receiving the light from the light source, extracting, from the light, the first etendue component and the second etendue component, providing the first etendue component to the first projection optics, and providing the second etendue component to the second projection optics.

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:.

This disclosure and aspects thereof can be embodied in various forms, including hardware 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.

In the following description, numerous details are set forth, such as circuit 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 exemplary and not intended to limit the scope of this application.

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.

<FIG> illustrates a block diagram of an exemplary projection system <NUM> according to various aspects of the present disclosure. Specifically, <FIG> illustrates a projection system <NUM> which includes a light source <NUM> configured to emit a first light <NUM>; an etendue splitter component <NUM> configured to receive the first light <NUM> and redirect it or otherwise modify it to create a first etendue component <NUM> and a second etendue component <NUM>; a phase light modulator (PLM) <NUM> configured to apply a spatially-varying phase modulation to the first etendue component <NUM> and/or the second etendue component <NUM>, thereby to steer the first etendue component <NUM> and/or the second etendue component <NUM> and generate a third light <NUM>; first projection optics <NUM> configured to receive the third light <NUM> and redirect or otherwise modify it, thereby to generate a fourth light <NUM>; a filter <NUM> configured to filter the fourth light <NUM>, thereby to generate a fifth light <NUM>; and second projection optics <NUM> configured to receive the fifth light <NUM> and project it as a sixth light <NUM> onto a screen <NUM>. The projection system may further include an amplitude-based spatial light modulator (SLM) or other additional modulators <NUM>', illustrated in <FIG> with a dotted line. While the etendue splitter component <NUM> is illustrated as being between the light source <NUM> and the PLM <NUM>, in practice the etendue splitter component <NUM> may be located in a separate location within the projection system <NUM> and after the light source <NUM> (i.e., between the first projection optics <NUM> and the filter <NUM>, etc.). Additionally, while the second etendue component <NUM> is illustrated as being delivered to the SLM <NUM>', the second etendue component <NUM> may be delivered to other components of the projection system <NUM>, such as the first projection optics <NUM>, the filter <NUM>, or the second projection optics <NUM>. The second etendue component <NUM> may be modified by a third projection optics <NUM>, illustrated in <FIG> with a dotted line. The third projection optics <NUM> may include an integrating rod or fly-eye array configured to homogenize the second etendue component <NUM>. In some embodiments, the first etendue component <NUM> is provided to the third projection optics <NUM>, and the second etendue component <NUM> is provided to the PLM <NUM>. By having one component bypass the PLM <NUM>, the overall optical efficiency may increase.

The projection system <NUM> further includes a controller <NUM> configured to control various components of the projection system <NUM>, such as the light source <NUM>, the PLM <NUM>, and/or the SLM <NUM>'. In some implementations, the controller <NUM> may additionally or alternatively control other components of the projection system <NUM>, including but not limited to the etendue splitter component <NUM>, the first projection optics <NUM>, and/or the second projection optics <NUM>. The controller <NUM> may be one or more processors such as a central processing unit (CPU) of the projection system <NUM>. The etendue splitter component <NUM>, the first projection optics <NUM>, and the second projection optics <NUM> may respectively include one or more optical components such as mirrors, lenses, waveguides, optical fibers, beamsplitters, diffusers, and the like. The controller <NUM> may control the light source <NUM> to control brightness (e.g., dimming) based on the image content. In some implementations, the etendue splitter component <NUM> may be configured to dynamically split the first light <NUM> into the first etendue component <NUM> and the second etendue component <NUM> based on the image content, as described in more detail below. When present, SLM <NUM>' may be controlled by the controller <NUM>. For example, the controller <NUM> may provide a control signal to the SLM <NUM>' to control the individual modulation elements of the SLM <NUM>'. With the exception of the screen <NUM>, the components illustrated in <FIG> 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. Components may further be split between two projectors. In some implementations, the first etendue component <NUM> and the second etendue component <NUM> are provided to separate projectors, as described in more detail below.

The light source <NUM> may be, for example, a laser light source, a light emitting diode (LED) array, and the like. Generally, the light source <NUM> is any light emitter which emits light. In some aspects of the present disclosure, the light source <NUM> may comprise multiple individual light emitters, each corresponding to a different wavelength or wavelength band. The light source <NUM> may include a fiber optic coupling, such as a single fiber coupled laser, a direct coupling, and the like. The light source <NUM> emits light in response to an image signal provided by the controller <NUM>. The image signal includes image data corresponding to a plurality of frames to be successively displayed. 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 <NUM> such as a hard disk, may originate from a removable medium that is operatively connected to the projection system <NUM>, or combinations thereof.

As illustrated in <FIG>, the controller <NUM> controls the PLM <NUM>, which receives light from the light source <NUM>. The PLM <NUM> imparts a spatially-varying phase modulation to the light, and directs the modulated light toward the first projection optics <NUM>. The PLM <NUM> may be a reflective type, in which the PLM <NUM> reflects incident light with a spatially-varying phase; alternatively, the PLM <NUM> may be of a transmissive type, in which the PLM <NUM> imparts a spatially-varying phase to light as it passes through the PLM <NUM>. In some aspects of the present disclosure, the PLM <NUM> has a liquid-crystal-on-silicon (LCOS) architecture. In other aspects of the present disclosure, the PLM <NUM> has a micro-electromechanical system (MEMS) architecture such as a digital micromirror device (DMD).

<FIG> illustrates one example of the PLM <NUM>, implemented as a reflective LCOS PLM <NUM> and shown in a partial cross-sectional view. As illustrated in <FIG>, the PLM <NUM> includes a silicon backplane <NUM>, a first electrode layer <NUM>, a second electrode layer <NUM>, a liquid crystal layer <NUM>, a cover glass <NUM>, and spacers <NUM>. The silicon backplane <NUM> includes electronic circuitry associated with the PLM <NUM>, such as complementary metaloxide semiconductor (CMOS) transistors and the like. The first electrode layer <NUM> includes an array of reflective elements <NUM> disposed in a transparent matrix <NUM>. The reflective elements <NUM> may be formed of any highly optically reflective material, such as aluminum or silver. The transparent matrix <NUM> may be formed of any highly optically transmissive material, such as a transparent oxide. The second electrode layer <NUM> may be formed of any optically transparent electrically conductive material, such as a thin film of indium tin oxide (ITO). The second electrode layer <NUM> may be provided as a common electrode corresponding to a plurality of the reflective elements <NUM> of the first electrode layer <NUM>. In such a configuration, each of the plurality of reflective elements <NUM> will couple to the second electrode layer <NUM> via a respective electric field, thus dividing the PLM <NUM> into any array of pixel elements. A pixel element may be, for example, the smallest addressable element of the PLM <NUM>, such as each of the plurality of reflective elements <NUM>. Thus, individual ones (or subsets) of the plurality of the reflective elements <NUM> may be addressed via the electronic circuitry disposed in the silicon backplane <NUM>, thereby to modify the state of the corresponding reflective element <NUM>. A subset of the pixel elements may be binned (or grouped) together for control in order to alter (e.g., lower) the native resolution of the PLM <NUM>.

The liquid crystal layer <NUM> is disposed between the first electrode layer <NUM> and the second electrode layer <NUM>, and includes a plurality of liquid crystals <NUM>. The liquid crystals <NUM> are particles which exist in a phase intermediate between a solid and a liquid; in other words, the liquid crystals <NUM> exhibit a degree of directional order, but not positional order. The direction in which the liquid crystals <NUM> tend to point is referred to as the "director. " The liquid crystal layer <NUM> modifies incident light entering from the cover glass <NUM> based on the birefringence Δn of the liquid crystals <NUM>, 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 <NUM>. This thickness is set by the spacer <NUM>, which seals the PLM <NUM> and ensures a set distance between the cover glass <NUM> and the silicon backplane <NUM>. The liquid crystals <NUM> generally orient themselves along electric field lines between the first electrode layer <NUM> and the second electrode layer <NUM>. As illustrated in <FIG>, the liquid crystals <NUM> near the center of the PLM <NUM> are oriented in this manner, whereas the liquid crystals <NUM> near the periphery of the PLM <NUM> are substantially non-oriented in the absence of electric field lines. By addressing individual ones of the plurality of reflective elements <NUM> via a phase-drive signal, the orientation of the liquid crystals <NUM> may be determined on a pixel-by-pixel basis.

<FIG> show another example of PLM <NUM>, implemented as a DMD <NUM>. <FIG> illustrates a plan view of the DMD <NUM>, and <FIG> illustrates a partial cross-sectional view of the DMD <NUM>. The DMD <NUM> includes a plurality of square micromirrors <NUM> arranged in a two-dimensional rectangular array on a substrate <NUM>. In some examples, the DMD <NUM> may be a digital light processor (DLP) from Texas Instruments. Each micromirror <NUM> may correspond to one pixel of the eventual projection image, and may be configured to tilt about a rotation axis <NUM>, shown for one particular subset of the micromirrors <NUM>, by electrostatic or other actuation. The individual micromirrors <NUM> have a width <NUM> and are arranged with gaps of width <NUM> therebetween. The micromirrors <NUM> 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 <NUM> may be absorptive, such that input light which enters a gap is absorbed by the substrate <NUM>.

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

As can be seen in <FIG>, each micromirror <NUM> may be connected to the substrate <NUM> by a yoke <NUM>, which is rotatably connected to the micromirror <NUM>. The substrate <NUM> includes a plurality of electrodes <NUM>. While only two electrodes <NUM> per micromirror <NUM> are visible in the cross-sectional view of <FIG>, each micromirror <NUM> may in practice include additional electrodes. While not particularly illustrated in <FIG>, the DMD <NUM> may further include spacer layers, support layers, hinge components to control the height or orientation of the micromirror <NUM>, and the like. The substrate <NUM> may include electronic circuitry associated with the DMD <NUM>, such as CMOS transistors, memory elements, and the like.

Regardless of which particular architecture is used for the PLM <NUM>, it is controlled by the controller <NUM> to take particular phase configurations on a pixel-by-pixel basis. Thus, the PLM <NUM> utilizes an array of the respective pixel elements, such as a 960x540 array. The number of pixel elements in the array may correspond to the resolution of the PLM <NUM>. The maximum resolution may be determined by the point-spread function (PSF) of the light source <NUM> and on parameters of various optical components in the projection system <NUM>. In some implementations, more than one PLM <NUM> may be used in conjunction with each other. In such a configuration each modulator may have a different number of pixel elements (for example, a first PLM <NUM> has a greater number of pixel elements than a second PLM <NUM>). Additionally, the PLM <NUM> may have a lower number of pixel elements than the SLM <NUM>'. Alternatively, the PLM <NUM> may have the same number or a greater number of pixel elements than the SLM <NUM>'.

Etendue is a measurement of the effective spatial and angular size of a light source, and is related to terms such as mm<NUM>*sr (steradians), M<NUM> factor, or beam parameter product (BPP). For projection systems based on beam steering, the smallest focused spot size (or pixel) of the projected image is dependent on the etendue level. In this manner, the spot size increases with etendue, and high etendue results in a low image quality (e.g., halos around bright objects, reduced maximum brightness, etc.). Accordingly, such projection systems often require laser light sources with low etendue.

When a fiber-coupled laser is used as the light source <NUM>, the etendue is based on the fiber radius and solid angle at the fiber output, as provided in Equation <NUM>: <MAT> Where:.

The solid angle at the fiber output is dependent on the numerical aperture of the fiber, as provided in Equation <NUM>: <MAT> Where:
NA = Numerical Aperture of Fiber.

Since the etendue is directly dependent on the radius, any given light source is composed of a plurality of etendue components. For example, when observing the center of a fiber-coupled laser and moving along the radius toward the outer limit of the laser, the measurement of etendue increases from a low etendue to a high etendue. Many projection systems, such as cinema projections, require high laser power, which may also result in a higher laser etendue. This high laser etendue leads to low efficiency and low image quality for the projector. In order to utilize high laser power while efficiently using high etendue light to drive projection systems that require lower etendue light, an etendue splitter component is implemented that breaks the laser output into several etendue components having different etendue levels.

<FIG> provides the etendue splitter component <NUM>, which includes a collimator <NUM>, a mirror <NUM> (shown as first mirror segment 402a and second mirror segment 402b), a high-etendue path <NUM>, an expander <NUM>, and a low-etendue path <NUM>. The light source <NUM> emits the first light <NUM>, which is received by the collimator <NUM>. The collimator <NUM> aligns the first light <NUM> into a collimated light <NUM>. The mirror <NUM> reflects a portion of the collimated light <NUM>, which is projected toward the high-etendue path <NUM> (e.g., a first etendue path) as a first etendue component <NUM> (e.g., a high etendue component). The remaining portion of the collimated light <NUM> is a second etendue component <NUM> (e.g., a low etendue component), and is received by the expander <NUM>. The expander <NUM> expands the second etendue component <NUM> into an expanded second etendue component <NUM>, which is then received by the low-etendue path <NUM> (e.g., a second etendue path). In some implementations, the second etendue component <NUM> may be provided directly to the low-etendue path <NUM> without the expansion.

The mirror <NUM> may be in a donut shape such that a center portion of the collimated light <NUM> is the second etendue component <NUM>, resulting in the first etendue component <NUM> being a donut shape. While the first etendue component <NUM> includes a hole in its center, the first etendue component <NUM> is considered to have its own etendue equivalent to a compact counterpart. Additionally, in some embodiments, a low-etendue component may have a hole, while the high-etendue component is compact. The center of the mirror <NUM> may be a circle, a rectangle, a square, or the like. When the center of the mirror <NUM> is a rectangle, the aspect ratio of the center of the mirror <NUM> may match the aspect ratio of the PLM <NUM>. By having the aspect ratio of the center of the mirror <NUM> match with the aspect ratio of the PLM <NUM>, less light is wasted and a greater amount of the second etendue component <NUM> is utilized. The resulting uniform illumination on the PLM <NUM> when the ratios match improves image quality by eliminating artifacts arising from the non-uniform illumination that occurs when the aspect ratios do not match.

Additionally, in some implementations, the mirror <NUM> may be dynamically adjustable to adjust the size and/or aspect ratio of the center based on the image content (for example, by moving sections of the mirror <NUM> along a track, by electrically controlling reflection characteristics of the mirror, etc.). Accordingly, the etendue splitter component <NUM> may be capable of being in several different states, each state having a different ratio of the first etendue component <NUM> to the second etendue component <NUM>. In some arrangements, the center of the mirror <NUM> (or a mirror reflecting second etendue component <NUM>) may have an aspect ratio that is substantially similar to the aspect ratio of PLM <NUM> (or other light modulator receiving second etendue component <NUM>), where substantially similar is understood to mean that, if the widths of the center of the mirror <NUM> and PLM <NUM> were scaled to be identical, then the height of the center of the mirror <NUM> would be within <NUM>% of the height of the PLM <NUM>.

Additional implementations of the etendue splitter component <NUM> are possible. For example, a similar mirror <NUM> may be used on a smaller scale (e.g., with a mirror pinhole). In one embodiment, the high-etendue path <NUM> includes a fiber that homogenizes the first etendue component <NUM>, removing the donut shape. The first etendue component <NUM> may be homogenized by other means, such as with integrating rods, diffusers, or fly-eye optics. In other implementations, a Fourier filter may be used to achieve angular filtering of the beam. One of the first etendue component <NUM> and the second etendue component <NUM> may be discarded based on the image content and/or the projector requirements. In such an implementation, the second etendue component <NUM> is reflected off a mirror, while the first etendue component <NUM> merely continues through to the high-etendue path <NUM> or is manipulated by additional optics (such as the expander <NUM> or other lenses configured to manipulate the size of the first etendue component <NUM>). In another implementation, the mirror <NUM> is a first mirror that reflects the first etendue component <NUM> at a first angle, and the center of the mirror <NUM> includes a second mirror configured to reflect the second etendue component <NUM> at a second angle. Each embodiment may include altered or additional optics such that the first etendue component <NUM> and the second etendue component <NUM> are sent to the desired downstream components in the desired form.

In one implementation, a mirror may reflect the center of the collimated light <NUM> (e.g., an inverse mirror of the mirror <NUM>). <FIG> provides the etendue splitter component <NUM> according to such an implementation. The etendue splitter component <NUM> of <FIG> includes a collimator <NUM>, a mirror <NUM>, a low-etendue path <NUM>, and a high-etendue path <NUM>. The light source <NUM> emits the first light <NUM>, which is received by the collimator <NUM>. The collimator <NUM> aligns the first light <NUM> into a collimated light <NUM>. The mirror <NUM> reflects a portion of the collimated light <NUM>, which is projected toward the low-etendue path <NUM> as a first etendue component <NUM> (e.g., a low etendue component). The remaining portion of the collimated light <NUM> is a second etendue component <NUM> (e.g., a high etendue component, illustrated as first high etendue component 512a and second high etendue component 512b). The second etendue component <NUM> enters the high-etendue path <NUM>. The first high etendue component 512a and the second high etendue component 512b may be homogenized as they move downstream, as described above.

<FIG> provides the etendue splitter component <NUM> according to another implementation. The etendue splitter component <NUM> of <FIG> includes a first collimator <NUM>, a second collimator <NUM>, a first axicon 608a, and a second axicon 608b (referred to collectively as axicons <NUM>). The first collimator <NUM> receives the first light <NUM>. The first collimator <NUM> aligns the first light <NUM> into a first collimated light <NUM>. The first collimated light <NUM> is received by the second collimator <NUM>. The second collimator <NUM> aligns the first collimated light <NUM> into a second collimated light <NUM>. The second collimated light includes a first etendue component <NUM> and a second etendue component <NUM>. The second etendue component <NUM> may enter a high-etendue path (not shown). The first etendue component <NUM> may be split among two sections (a first section 606a and a second section 606b).

The first axicon 608a and the second axicon 608b may each be flat top axicons with a flat central section. The flat central section of the axicons <NUM> directs the first etendue component <NUM> to a low-etendue path (not shown). The diameter of the flat central section of the axicons <NUM> may be altered to accommodate precisely the amount of light needed for the low-etendue path section of the projection system <NUM>. Outer angled sections of the axicons <NUM> may refract the first etendue component <NUM> such that the first etendue component <NUM> is easily directed to the low-etendue path.

In some implementations, etendue separation occurs directly at the light source <NUM>. For example, <FIG> provides the etendue splitter component <NUM> according to such an embodiment. The etendue splitter component <NUM> includes a mirror <NUM>, a high-etendue path <NUM>, and a low-etendue path <NUM>. The light source <NUM> is an array composed of a plurality of sources <NUM>. The light source <NUM> projects a first light <NUM> composed of a first etendue component <NUM> (e.g., a high-etendue component) and a second etendue component <NUM> (e.g., a low-etendue component). A first subset of the plurality of sources <NUM> may be configured to project the first etendue component <NUM>, and a second subset of the plurality of sources <NUM> may be configured to project the second etendue component <NUM>. The selected sources <NUM> for each subset may be interleaved with each other. The first etendue component <NUM> directly enters the high-etendue path <NUM>. The second etendue component <NUM> reflects off of mirror <NUM> and enters the low-etendue path <NUM>. In other implementations, additional optics may be located within the light source <NUM> and the high-etendue path <NUM> and/or the low-etendue path <NUM>.

With reference to <FIG>, the ratio of the second etendue component <NUM> to the first etendue component <NUM> (e.g., ratio of low-etendue to high-etendue) present varies based on the size of the collimated light <NUM>, dependent on the etendue of the light source <NUM>, the amount of light energy desired in each path, and the size of each modulator. <FIG> provides a graph illustrating the relationship between the first etendue component <NUM> and the second etendue component <NUM> as the radius of the collimated light <NUM> increases while holding the size of the low etendue aperture in the filter constant. The size of the collimated light <NUM> may be selected based on the desired angle at the SLM <NUM>'. Additionally, only a fraction of the power of the collimated light <NUM> arrives at the SLM <NUM>', provided by Equation <NUM>: <MAT> Where:.

Accordingly, the size of the collimated light <NUM> (e.g., Rill) can be adjusted based on the desired image and requirements of the projector. While Equation <NUM> defines a circular beam, as previously described, other beam shapes and sizes may also be utilized (such as a square or rectangular beam).

The first etendue component <NUM> and the second etendue component <NUM> (or the expanded second etendue component <NUM>, henceforth referred to as equivalents) are provided to the high-etendue path <NUM> and low-etendue path <NUM>, respectively. The high-etendue path <NUM> and the low-etendue path <NUM> may both each lead to separate projectors. For example, <FIG> provides an exemplary projection system <NUM> that includes a first projector <NUM> and a second projector <NUM>. The etendue splitter component <NUM> is connected to the first projector <NUM> by the high-etendue path <NUM>, and the etendue splitter component <NUM> is connected to the second projector <NUM> by the low-etendue path <NUM>. The first projector <NUM> and the second projector <NUM> may both include components of the projection system <NUM> (shown in <FIG>), such as the PLM <NUM>, the first projection optics <NUM>, the filter <NUM>, the SLM <NUM>', the second projection optics <NUM>, and/or the controller <NUM>. Accordingly, the first projector <NUM> may include a first projection optics, and the second projector <NUM> may include a second projection optics. The first projector <NUM> and the second projector <NUM> may each have different capabilities. For example, the first projector <NUM> may be a standard DLP high-etendue projector with a per-pixel light budget, while the second projector <NUM> may be a beam-steering low-etendue projector with a global light budget. Additionally, since the first projector <NUM> receives the first etendue component <NUM>, the image projected by the first projector <NUM> on the screen <NUM> includes, or is based on, the first etendue component <NUM>. Accordingly, the second projector <NUM> receives the second etendue component <NUM>, and the image projected by the second projector <NUM> on the screen <NUM> includes, or is based on, the second etendue component <NUM>.

Each projector is capable of utilizing its respective etendue component in a different manner. For example, the first projector <NUM> may use the high-etendue path <NUM> to project a component of the desired image that is generated with a normal DLP (or amplitude modulator). The second projector <NUM>, meanwhile, may use the low-etendue path <NUM> to project a separate component of the desired image, which may use beam-steering to achieve higher peak highlights. The images are then projected on top of each other on the screen <NUM>.

The first projector <NUM> and the second projector <NUM> may also display the same image on the screen <NUM>, but perform different optical operations on the first etendue component <NUM> and the second etendue component <NUM>.

<FIG> provides an additional exemplary projection system <NUM> in which the etendue splitter component <NUM> is located within the second projector <NUM>. The low-etendue path <NUM> is within the second projector <NUM>, and the second projector <NUM> is driven using the second etendue component <NUM>. The first projector <NUM> receives the first etendue component <NUM> via the high-etendue path <NUM>. In implementations where the light source <NUM> is fiber coupled, the fiber size from the light source <NUM> may be smaller than the fiber for the first projector <NUM> (which is a high-etendue projector). Since the first projector <NUM> therefore does not require a small fiber, the efficiency of the system is increased by using a larger fiber for the high-etendue path <NUM>.

<FIG> provides another exemplary projection system <NUM> in which the high-etendue path <NUM> and the low-etendue path <NUM> both are within first projector <NUM>. The first etendue component <NUM> (from the high-etendue path <NUM>) and the second etendue component <NUM> (from the low-etendue path <NUM>) are combined for a single image output. The combination of the first etendue component <NUM> and the second etendue component <NUM> may occur anywhere within the projection system <NUM> following the etendue splitter component <NUM>. For example, the first etendue component <NUM> and the second etendue component <NUM> may both converge onto the same modulator, such as the SLM <NUM>', or prior to the modulator, such as at the first projection optics <NUM>. Combining the first etendue component <NUM> and the second etendue component <NUM> may be performed using any suitable technique for combining light paths, such as a wavelength-based technique, a polarization-based technique, or the like. Additional techniques for combining light paths may be found in <CIT>, "Aperture Sharing for Highlight Projection". By recombining the first etendue component <NUM> and the second etendue component <NUM>, the first light <NUM> is fully utilized to provide an image on the screen <NUM>.

In other implementations, two lights of two different wavelengths (e.g., different colors) may be provided to two separate etendue splitter components. For example, a first light is split into a first etendue component and a second etendue component, and a second light is split into a third etendue component and a fourth etendue component. The first etendue component may then be combined with the fourth etendue component, and the second etendue component may then be combined with the third etendue component. Accordingly, lights of varying wavelengths and polarization states may be combined while still efficiently utilizing the high and low etendue components of each.

In some implementations, the projection system includes a plurality of different wavelengths, each wavelength provided to a color channel. Each color channel may comprise, for example, the components recited with respect to projection system <NUM>. In this manner, each color channel may include its own PLM <NUM> and/or its own SLM <NUM>'. Additionally, each color channel may include its own etendue splitter component <NUM>. Alternatively, in some implementations, the same etendue splitter component <NUM> is shared for two or more color channels or for every color channel.

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.

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.

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.

Claim 1:
A projection system (<NUM>) for etendue utilization, the projection system comprising:
a light source (<NUM>) configured to emit a light (<NUM>), the light including a first etendue component (<NUM>) and a second etendue component (<NUM>), wherein the first etendue component has a lower etendue than the second etendue component;
a first projection optics (<NUM>) configurable to project an image on a screen (<NUM>);
a second projection optics (<NUM>) configurable to project an image on a screen (<NUM>); and
an etendue splitter component (<NUM>), the etendue splitter component configured to:
receive the light from the light source,
extract, from the light, the first etendue component and the second etendue component,
provide the first etendue component to the first projection optics, and
provide the second etendue component to the second projection optics,
wherein the first projection optics are configured to project a first image using the first etendue component and the second projection optics are configured to project a second image using the second etendue component.