Wearable head-up display including visual artifact reduction combiner - Patent Application 20070122997

Abstract

A wearable head-up display (WHUD) reduces the occurrence of visual artifacts by using a projector in conjunction with a combiner that includes multiple combiner elements, such as dichroic prisms. The projector is configured with one or more features, or any combination thereof, that 1) reduce the amount of stray light generated at the combiner, or 2) redirect the stray light so that it cannot exit the projector and therefore cannot create visual artifacts. As described herein, reducing the generated stray light and redirecting the stray light reduces the likelihood of visual artifacts appearing in a user's eyes, thereby improving the user experience with the WHUD system.

Description

[Background technology]

[0001] The present disclosure generally relates to augmented reality (AR) eyewear that blends real-world views with a head-up display overlay. A wearable head-up display (WHUD) is a wearable electronic device that uses an optical combiner to combine a real-world image with a virtual image. The optical combiner may be integrated with one or more lenses to provide a combiner lens that can be incorporated into the support frame of the WHUD. During operation, the combiner lens provides a virtual display that a user can see when the WHUD is worn on the user's head. Some optical combiners transmit light using a waveguide (also called a light guide). Generally, light from a projector in the WHUD enters the combiner's waveguide through an in-coupler, propagates along the waveguide via total internal reflection (TIR), and exits the waveguide through an out-coupler. When the eye's pupil is aligned with one or more exit pupils provided by the out-coupler, at least a portion of the light exiting the out-coupler enters the eye's pupil, thereby enabling the user to see the virtual image. The optical combiner lens is transparent so the user can also see the real world.

[0002] The present disclosure may be better understood, and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings, in which: The use of the same reference symbols in different drawings indicates similar or identical items. [Brief explanation of the drawings]

[0003] [Figure 1] 1 illustrates a portion of an augmented reality (AR) display system, according to some embodiments. [Figure 2] 1 illustrates a portion of an augmented reality (AR) display system, according to some embodiments. [Figure 3] 1 illustrates an example of a dichroic prism projector, according to some embodiments. [Figure 4]10 illustrates an example of how a dichroic prism projector creates visual artifacts in a WHUD, according to some embodiments. [Figure 5] 1 illustrates an example of a portion of a dichroic prism projector that includes apertures in the dichroic coating to reduce visual artifacts, according to some embodiments. [Figure 6] FIG. 1 illustrates an example of a dichroic prism projector that uses lenses to reduce visual artifacts, according to some embodiments. [Figure 7] 1 illustrates an exemplary dichroic prism projector with angled sides to reduce visual artifacts, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0004] WHUD systems are typically configured to display images by transmitting light to a user's eyes through an optical combiner lens. In many systems, such as those having an eyeglass form factor, the lenses are positioned relatively close to the user's eyes. However, at such a distance, the user's eyes may be particularly sensitive to visual artifacts, such as artifacts caused by stray light (e.g., light that is not properly positioned relative to the source image). Therefore, it is desirable to reduce the occurrence of visual artifacts in WHUD systems while maintaining a relatively small footprint for the projector and other optical components.

[0005] To maintain a small footprint, some WHUD systems use projectors that include a combiner with multiple combiner elements arranged as cross members within a cubic structure, also known as an X-cube. The combiner includes a housing generally shaped like a cube, with combiner elements (e.g., prisms) arranged along the diagonals of the cube. In some embodiments, dichroic coatings are sandwiched between the prisms to selectively pass or reflect specific states of light, such as light of different colors or polarizations. The projector includes panels (e.g., red, green, and blue panels) that generate different states of light based on the corresponding image to be displayed. The panels are arranged so that each panel transmits light through a different face of the cubic housing, and the dichroic coatings are selected so that each coating surface reflects light in one of the states and transmits light in the other states. For example, in some embodiments, the dichroic coating of a first prism reflects red light and transmits green and blue light, while the dichroic coating of a second prism reflects blue light and transmits green and red light. With this arrangement, the dichroic prisms are configured to combine the red, green, and blue light generated by each panel into an output beam for delivery to an incoupler of the WHUD (e.g., via a set of lenses). However, in at least some cases, light from at least one panel (e.g., green light) reflects off a portion of a face of the cubic housing, resulting in the combined light containing unwanted or "stray" light and causing visual artifacts to be projected by the WHUD.

[0006] 1-7 illustrate techniques for reducing the occurrence of visual artifacts in a WHUD that uses a projector with a combiner that includes multiple combiner elements, such as dichroic prisms. In some embodiments, the projector is configured with one or more features, or any combination thereof, that 1) reduce the amount of stray light generated in the combiner, or 2) redirect the stray light so that it cannot exit the projector and therefore cannot create visual artifacts. As described herein, reducing the stray light generated and redirecting the stray light reduces the likelihood of visual artifacts being seen by a user, thereby improving the user experience with the WHUD system.

[0007] To illustrate, in some embodiments, the dichroic coating of the dichroic prism is configured with an aperture over a portion of each prism face, i.e., the dichroic coating is applied so that stray light is absorbed, scattered, reflected, or redirected by the aperture. The aperture is positioned to prevent stray light of a specified color from exiting the projector, thereby reducing the likelihood that the light will cause visual artifacts.

[0008] In some embodiments, a lens is disposed on the output face of the cube structure. The lens is shaped to reflect light that enters the lens within a specified range of angles so that the light undergoes total internal reflection and therefore does not exit the projector. In some embodiments, an absorbing surface is disposed on the exterior of the exit face to absorb the reflected light.

[0009] In another embodiment, one or more faces of the cube are angled relative to the input face of one of the panels (e.g., the green panel). This arrangement reflects the input light so that at least some of the stray light is not sent to the projector lens and therefore not sent to the in-coupler of the WHUD system. That is, the cube structure is shaped so that some of the stray light cannot reach the system's exit pupil and is therefore not visible to the user.

[0010] 1 illustrates an exemplary display system 100 using an AR optical system, according to some embodiments. The display system 100 has a support structure 102 including an arm 104 that houses a projector including a dichroic prism structure. The projector is configured to project an image toward a user's eye via a waveguide (not shown), so that the user, via an out-coupler, perceives the projected image as being displayed within a field of view (FOV) region 106 of a display located on a lens element 110. In the illustrated embodiment, the display system 100 is a near-eye display system in the form of a WHUD, in which the support structure 102 is configured to be worn on the user's head and has the general shape and appearance (i.e., form factor) of a pair of eyeglasses (e.g., sunglasses) frame.

[0011] The support structure 102 houses or otherwise includes various components, such as a projector and a waveguide, to facilitate the projection of such images toward the user's eyes. In some embodiments, the support structure 102 further includes various sensors, such as one or more front-facing cameras, rear-facing cameras, other light sensors, motion sensors, accelerometers, etc. In some embodiments, the support structure 102 includes one or more radio frequency (RF) interfaces or other wireless interfaces, such as a Bluetooth interface, a WiFi interface, etc. Additionally, in some embodiments, the support structure 102 further includes one or more batteries or other portable power sources for powering the electrical components of the display system 100. In some embodiments, some or all of these components of the display system 100 are contained entirely or partially within the interior volume of the support structure 102, such as within the arms 104 of region 112 of the support structure 102. It should be noted that while an exemplary form factor is shown, in other embodiments, the display system 100 may have a different shape and appearance than the eyeglass frames shown in FIG. 1 . Unless otherwise specified, instances of the term "or" herein should be understood to refer to a non-exclusive definition of "or." For example, the phrase "X or Y" herein means "either X or Y, or both."

[0012] One or both of lens elements 108, 110 may be used by display system 100 to provide an augmented reality (AR) display in which rendered graphical content is provided superimposed on or otherwise combined with a real-world view perceived by a user through lens elements 108, 110. For example, the projection system of display system 100, according to various embodiments, uses light to form a perceptible image or series of images by projecting display light to a user's eye through a projector of the projection system, a waveguide formed at least partially within the corresponding lens element 108 or 110, and one or more optical elements (e.g., one or more retro-reflective optical elements, scan mirrors, optical relays, or collimation lenses disposed between the projector and the waveguide or integrated with the waveguide).

[0013] One or both of the lens elements 108, 110 comprise a lens stack having multiple layers, at least one of which includes at least a portion of a waveguide that directs display light received by a waveguide in-coupler to a waveguide out-coupler. The waveguide outputs the display light toward the eye of a user of the display system 100. The display light is modulated and projected to the user's eye so that the user perceives the light as an image. Additionally, each of the lens elements 108, 110 is sufficiently transparent to allow the user to see through the lens element, thereby providing a view of the user's real-world environment, whereby the image appears superimposed on at least a portion of the real-world environment.

[0014] In some embodiments, the projector of the projection system of display 100 is a digital light processing-based projector or any combination of light sources, such as a set of lasers or one or more light-emitting diodes (LEDs), and a combiner that combines the light sources into a projection light beam. In some embodiments, the projector is configured to input the projection light beam (representing an image or portion of an image for display) into a waveguide of the projector. The waveguide expands the display light and outputs the display light through an out-coupler toward the user's eye.

[0015] The projector is communicatively coupled to a controller and a non-transitory processor-readable storage medium or memory that stores processor-executable instructions and other data that, when executed by the controller, cause the controller to control operation of the projector. In some embodiments, the controller controls the projector to selectively set the position and size of the FOV via the out-coupler region 106. In some embodiments, the controller is communicatively coupled to one or more processors (not shown) that generate content to be displayed on the display system 100. The projector outputs display light via a waveguide toward the out-coupling region 106 of the display system 100. In some embodiments, at least a portion of the out-coupler of the waveguide overlaps with the FOV region. The range of different user eye positions from which a display can be viewed is referred to herein as the eyebox of the display.

[0016] 2 shows a portion of a display system 200 including a projection system having a projector 208 and a waveguide 212 with one or more optical paths between an in-coupler 214 and an out-coupler 216 of the waveguide 212. In some embodiments, the display system 200 corresponds to the display system 100 of FIG. 1. In this example, an arm 204 of the display system 200 houses the projector 208 including an optical engine (e.g., one or more display panels) having a combiner, the in-coupler 214, and a portion of the waveguide 212.

[0017] In one particular embodiment, the combiner is a cross-dichroic prism, also known as an X-cube. In an embodiment, the combiner is configured with one or more features to reduce the effect of stray light on the displayed image, such as an aperture in the dichroic coating of the prism, a lens that redirects stray light away from the in-coupler, or an angled surface that directs stray light away from the in-coupler 214.

[0018] The display system 200 includes an optical combiner lens 218 that includes a first lens 220, a second lens 222, and a waveguide 212, where the waveguide 212 is embedded or otherwise disposed between the first lens 220 and the second lens 222.

[0019] Light exiting outcoupler 216 passes through first lens 220 (which may, for example, correspond to an embodiment or portion of lens element 110 of display system 100). In use, display light exiting first lens 220 enters the pupil of eye 224 of a user wearing display system 200, causing the user to perceive a display image conveyed by display light output from optical engine 208. Because optical combiner lens 218 is substantially transparent, at least some light from a real-world scene corresponding to the environment around display system 200 passes through second lens 222, waveguide 212, and first lens 220 to reach user's eye 224. In this way, an image or other graphical content output by projector 208, when projected onto the user's eye 224, is combined (e.g., overlaid) with a real-world image of the user's environment to provide the user with an AR experience.

[0020] Waveguide 212 of display system 200 includes two diffractive structures: in-coupler 214 and out-coupler 216. In some embodiments, one or more exit pupil expanders, such as a diffraction grating, are positioned intermediate between in-coupler 214 and out-coupler 216 to receive light coupled into waveguide 212 by in-coupler 214, expand the received display light in the one or more exit pupil expanders, and redirect the light to out-coupler 216, which then couples the display light out of waveguide 212 (e.g., toward a user's eye 224).

[0021] As used herein, the term "waveguide" is understood to mean a combiner that transfers light from an in-coupler (such as in-coupler 214) to an out-coupler (such as out-coupler 216) using one or more of total internal reflection (TIR), special filters, or reflective surfaces. In some display applications, the display light is a collimated image, and the waveguide transfers and replicates the collimated image to the eye. In general, the terms "in-coupler" and "out-coupler" are understood to refer to any type of optical grating structure, including, but not limited to, a diffraction grating, a hologram, a holographic optical element (e.g., an optical element using one or more holograms), a volume diffraction grating, a volume hologram, a surface-relief diffraction grating, or a surface-relief hologram. In some embodiments, a given in-coupler or out-coupler is configured as a transmission grating (e.g., a transmission diffraction grating or a transmission holographic grating) that transmits the display light to the in-coupler or out-coupler. In some embodiments, a given in-coupler or out-coupler is a reflective grating (e.g., a reflective diffraction grating or a reflective holographic grating), which reflects light back to the in-coupler or out-coupler. In this example, the in-coupler 214 relays the received display light to the out-coupler 216 via multiple optical paths through a waveguide. In some embodiments, the in-coupler 214 redirects a first portion of the display light to the out-coupler 216 via a first optical path in which a first exit-pupil expander (not shown, implemented in some embodiments as a folding grating) is disposed, and redirects a second portion of the display light toward the out-coupler 216 via a second optical path in which a second exit-pupil expander (not shown, implemented in some embodiments as a folding grating) is disposed. The display light propagates through the waveguide 212 via TIR. The out-coupler 216 then outputs the display light to the user's eye 224.

[0022] In some embodiments, the projector 208 is coupled to a driver or other controller (not shown), which controls the timing of the emission of display light from the light sources (e.g., LEDs) of the projector 208 according to instructions received by the controller or driver from a computer processor (not shown) coupled to the controller, and modulates the output light so that it is perceived as an image when output to the retina of a user's eye 224. For example, during operation of the display system 200, the light sources of the projector 208 output light of selected wavelengths, and the output light is directed to the user's eye 224 via the waveguide 212. The projector 208 modulates the intensity of each of its light sources so that the output light represents a pixel of the image. For example, the intensity of a given light source or group of light sources of the projector 208 corresponds to the brightness of a corresponding pixel of an image projected by the projector 208 of the display system 200.

[0023] FIG. 3 illustrates an example of a projector 208 according to some embodiments. In the illustrated example, the projector 208 includes a set of light sources including a red light source 330, a green light source 331, and a blue light source 332. The projector 208 also includes a combiner 335, a lens set 338, and a projection lens 337. The red light source 330, the green light source 331, and the blue light source 332 are each configured to generate light of a corresponding color (red, green, and blue, respectively) based on a set of instructions or signaling representing an image to be displayed. In some embodiments, the red light source 330, the green light source 331, and the blue light source 332 are each panel light sources. In other embodiments, the red light source 330, the green light source 331, and the blue light source 332 are laser light sources, micro-LED light sources, etc. It will be appreciated that in various embodiments, the light sources 330-332 each provide light in a different state, such as a different color (as described above), a different polarization, etc., or any combination thereof.

[0024] Combiner 335 includes a housing having a generally cubic structure, and each of light sources 330-332 is positioned facing a corresponding face of the cube such that light projected by the light source is projected toward the corresponding face of the cube. For example, surface 341 of the cube is positioned facing green light source 331. Thus, light projected by each of light sources 330-332 passes through the corresponding face of the cube and reaches the interior of combiner 335. Thus, for example, surface 341 is constructed of a transparent material so that green light generated by green light source 331 passes through the interior of the housing of combiner 335.

[0025] Combiner 335 further includes cross surfaces 342 and 343, each of which is disposed along a corresponding body diagonal of the cube. Thus, cross surfaces 342 and 343 form an X-shape within combiner 335. Cross surfaces 342 and 343 are constructed of a generally transparent material to allow light to pass through, and at least a portion of each of cross surfaces 342 and 343 is coated with a dichroic coating that reflects light of a corresponding color. Specifically, in the example of FIG. 3 , cross surface 342 is coated with a dichroic coating that reflects red light and transmits green and blue light, and cross surface 343 is coated with a dichroic coating that reflects blue light and transmits red and green light. The effect of this configuration of dichroic coatings is that red light generated by red light source 330 and blue light generated by blue light source 332 are each reflected by the corresponding cross surface toward cube face 336. Additionally, cross surfaces 342 and 343 allow green light to pass through. This allows green light generated by green light source 331 to pass through surface 341 and toward surface 336. Surface 336 is constructed of a transparent material that allows red, green, and blue light to pass through. Thus, combiner 335 combines the red, green, and blue light into an output beam having all three colors of light and transmits the combined light out of surface 336 of combiner 335.

[0026] In the illustrated embodiment, face 336 of combiner 335 is positioned opposite lens set 338. The combined output light of dichroic prism face 336 is thus projected toward lens set 338, where the direction, refractive power, and other properties of the output light are modified according to the shape of each of the lenses. Lens 337 receives light from lens set 338 and projects the received light out of projector 208 (e.g., toward incoupler 214). In some embodiments, lens set 338, including lens edges, apertures, and barrels, also reduces or eliminates stray light as it absorbs, blocks, or redirects unwanted light.

[0027] As mentioned above, in some cases, the path of at least some of the light from one or more of the light sources 330-332 is misdirected based on surface reflections at the combiner 335. FIG. 4 illustrates an example according to some embodiments. In the illustrated example, at least some of the green light generated by the green light source 331 is reflected off the interior surfaces of the cube, including the interior surfaces facing the red and blue light sources 330 and 331. As a result of this reflection, some of the green light is not properly positioned within the output beam of the projector 208, at least for the image to be projected. For example, in some cases, reflections of the green light (sometimes referred to herein as "stray" light) result in a green "ghost" effect or other visual artifacts in the image projected by the projector 208. To ameliorate the effects of these visual artifacts, in some embodiments, the combiner 335 includes one or more features that reduce the likelihood of stray light reaching the in-coupler 214.

[0028] For example, in some embodiments, combiner 335 includes apertures in one or more of the dichroic coatings. The apertures are located on one or more of the cross faces of the cube, the faces of the cube, or any combination thereof, and are arranged to reduce reflection of light from the interior surfaces of the cube. An example according to some embodiments is shown in FIG. 5 . In the example shown, apertures are located in the dichroic coatings of cross faces 342 and 343 near the corners of the cube and around each of cross faces 342 and 343. Thus, cross face 342 includes coating aperture 552 and coating region 553, and cross face 343 includes coating aperture 555 and coating region 554. Coating apertures 552 and 555 do not include a dichroic coating and therefore reflect, scatter, redirect, or absorb green light, while coating regions 553 and 554 allow green light to pass. By placing coated apertures 552 and 555 around cross faces 342 and 343, respectively, the amount of unwanted green light that reflects off the interior surfaces of the cube is reduced, thereby reducing the amount of stray green light projected by projector 208 and therefore reducing the visibility of any artifacts.

[0029] Coated openings 552 and 555 can be created in any of several ways. For example, in some embodiments, a dichroic coating is applied to the entirety of each cross face, and then an absorbing coating is applied to the areas corresponding to coated openings 552 and 555. In some embodiments, when the dichroic coating is applied to cross faces 342 and 343, a mask is placed over the areas corresponding to openings 552 and 555 so that the respective dichroic coating is not applied to these areas. In other embodiments, a dichroic coating is applied to the entirety of each cross face, and then the coating is removed in the areas corresponding to coated openings 552 and 555 by etching, washing, or other removal techniques.

[0030] In some embodiments, projector 208 includes one or more lenses that direct stray light so that at least a substantial portion of the stray light is not transmitted to in-coupler 214, thereby reducing the likelihood of visual artifacts in the resulting image. FIG. 6 illustrates an example according to some embodiments. In the illustrated example, projector 208 includes lens 655 positioned between face 336 and lens 338 of combiner 335. Lens 655 is thus positioned to receive light output at face 336, including stray green light. As shown in FIG. 6, lens 655 is configured to reflect light away from lens 338. That is, the shape and position of lens 655 have the effect of reflecting light received at a specified angle and position back toward combiner 335 and away from lens 338. However, lens 655 is also shaped and positioned such that light received by lens 655 at other specified positions and angles is transmitted to lens 338. In other words, the configuration of lens 655 redirects unwanted light away from lens 338 and thus away from intercoupler 214, while directing light for display to lens 338. Thus, stray green light is reflected away from intercoupler 214, and light corresponding to the image for display is directed to intercoupler 214, improving the overall quality of the displayed image.

[0031] In some cases, light reflected by lens 655 may in turn be reflected off other surfaces of projector 208, potentially resulting in visual artifacts. Therefore, to further reduce the likelihood of visual artifacts, in some embodiments, projector 208 includes an absorbing surface 656. Absorbing surface 656 is configured to absorb light in a specified wavelength range, and therefore light of a particular color. For example, in some embodiments, absorbing surface 656 is configured to absorb green light (i.e., light in a wavelength range corresponding to the color green). In some embodiments, absorbing surface 656 is configured by coating the absorbing surface with a pigment or other material that absorbs light of the corresponding color. Absorbing surface 656 is positioned within projector 208 to absorb light reflected by lens 655. For example, in the example of FIG. 6 , the absorbing surface is positioned at or near light sources 330 and 332. Thus, the absorbing surface absorbs green light reflected by lens 655, reducing the likelihood that the reflected green light will cause visual artifacts or other errors.

[0032] In some embodiments, the shape of combiner 335 is configured to prevent stray light from being transmitted to in-coupler 214. FIG. 7 illustrates an example according to some embodiments. Specifically, FIG. 7 illustrates combiners 765 and 766, each having a sloped surface that directs stray light away from in-coupler 214. For example, combiner 765 includes a surface 341 facing light source 331, a surface 760 facing light source 330, and a surface 761 facing light source 332. Surfaces 760 and 341 are positioned and connected such that surfaces 760 and 341 form an obtuse angle. Similarly, surfaces 761 and 341 are positioned and connected such that surfaces 761 and 341 form an obtuse angle. The effect of this configuration is that some green light, particularly stray green light, is not transmitted to lens 338 and therefore not transmitted to in-coupler 214. Thus, no stray light is transmitted to the display, reducing the possibility of ghosting or other visual artifacts.

[0033] Dichroic prism 766 includes surface 341 facing light source 331, surface 762 facing light source 330, and surface 763 facing light source 332. Surfaces 762 and 341 are positioned and connected such that surfaces 762 and 341 form an acute angle. Similarly, surfaces 763 and 341 are positioned and connected such that surfaces 763 and 341 form an acute angle. The effect of this configuration is that some of the green light, particularly stray green light, is transmitted to lens 338 but at an angle that prevents the light from being transmitted to in-coupler 214. Thus, stray light is not transmitted to the display, reducing the possibility of ghosting or other visual artifacts.

[0034] In some embodiments, certain aspects of the techniques described above may be performed by one or more processors of a processing system executing software. The software includes one or more sets of executable instructions stored on, or otherwise tangibly embodied in, a non-transitory computer-readable storage medium. The software may include instructions and specific data that, when executed by, one or more processors, operate to cause the one or more processors to perform one or more aspects of the techniques described above. Non-transitory computer-readable storage media may include, for example, magnetic or optical disk storage devices, solid-state storage devices such as flash memory, cache, random access memory (RAM), or other non-volatile memory device or devices, and the like. The executable instructions stored on the non-transitory computer-readable storage medium may be in the form of source code, assembly language code, object code, or other instruction formats that are interpreted or otherwise executable by one or more processors.

[0035] A computer-readable storage medium may include any storage medium, or combination of storage media, that is accessible by a computer system during use to provide instructions and / or data to the computer system. Such storage media may include, but are not limited to, optical media (e.g., compact discs (CDs), digital versatile discs (DVDs), Blu-ray discs), magnetic media (e.g., floppy disks, magnetic tape, or magnetic hard drives), volatile memory (e.g., random access memory (RAM) or cache memory), non-volatile memory (e.g., read-only memory (ROM) or flash memory), or microelectromechanical systems (MEMS)-based storage media. A computer-readable storage medium may be incorporated into a computing system (e.g., system RAM or ROM), fixedly attached to a computing system (e.g., a magnetic hard drive), removably attached to a computing system (e.g., an optical disk or universal serial bus (USB)-based flash memory), or connected to a computer system via a wired or wireless network (e.g., network-accessible storage (NAS)).

[0036] It should be noted that not all of the operations or elements described above in the general description are required, that some of the particular operations or devices may not be required, and that one or more additional operations may be performed or elements in addition to those described above may be included. Furthermore, the order in which activities are listed is not necessarily the order in which they are performed. Also, concepts have been described with reference to specific embodiments. However, those skilled in the art will recognize that various modifications and changes can be made without departing from the scope of the present disclosure, as set forth in the claims below. Accordingly, the specification and drawings should be regarded in an illustrative rather than a restrictive sense, and all such variations are intended to be within the scope of the present disclosure.

[0037] Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, and solutions to problems, as well as any feature or features that may cause or make more pronounced any benefit, advantage, or solution, should not be construed as critical, necessary, or essential features of any or all claims. Moreover, the specific embodiments disclosed above are exemplary only, as the disclosed inventive subject matter may be modified and practiced in different but equivalent manners that will be apparent to those skilled in the art having the benefit of the teachings herein. No limitations are intended to the details of construction or design herein shown, other than as set forth in the claims below. It is therefore apparent that the particular embodiments disclosed above may be altered or modified, and that all such variations are considered within the scope of the disclosed inventive subject matter. Accordingly, the protection sought herein is as set forth in the claims below.

Claims

1. A projector, a plurality of light sources including a first light source that emits light in a first state and a second light source that emits light in a second state; a combiner, the combiner comprising: a first cross surface; a first coating on the first cross surface that transmits light in the first state and reflects light in the second state, the first coating having a first aperture.

2. The projector of claim 1 , wherein the first state and the second state each include a different color of light.

3. 10. The projector of claim 1, wherein the first aperture at least one of absorbs, reflects, scatters, or redirects light in the first state.

4. The combiner further comprises: a second cross surface; 10. The projector of claim 1, further comprising a second coating on said second cross surface, said second coating having a second opening.

5. the plurality of light sources includes a first light source that emits light in a first state and a second light source that emits light in a second state; 5. The projector of claim 4, wherein the first coating transmits light in the first state and reflects light in the second state, and the second coating transmits light in the first state and reflects light in a third state.

6. 6. The projector of claim 5, wherein the second opening reflects light of the first color.

7. further comprising a lens disposed at the output of the combiner; The projector of claim 6 , wherein the first opening and the second opening are positioned so that a portion of the light in the first state does not reach the lens.

8. A projector, a plurality of light sources including a first light source that emits light in a first state and a second light source that emits light in a second state; a combiner that receives light from the plurality of light sources and provides an output light, the combiner including a first coating that transmits light in the first state and reflects light in the second state, the projector further comprising: A projector including a first lens that reflects a first portion of the output light away from the first lens.

9. 9. The projector of claim 8, wherein the first state and the second state each include a different color of light.

10. The projector of claim 9 , further comprising an absorbing surface that absorbs light in the first state.

11. 11. The projector of claim 10, wherein the absorbing surface is positioned to receive the light reflected by the first lens.

12. 10. The projector of claim 9, further comprising a second lens, the first lens transmitting a second portion of the output light to the second lens.

13. 10. The projector of claim 9, wherein the second lens delivers the second portion of the light to a waveguide in-coupler.

14. the plurality of light sources includes a first light source that emits light in a first state and a second light source that emits light in a second state; 9. The projector of claim 8, wherein the first coating transmits light in the first state and reflects light in the second state, and the second coating transmits light in the first state and reflects light in a third state.

15. A projector, Multiple light sources; a combiner, the combiner comprising: a first cross surface; a housing including a first surface connected to the first cross surface and a second surface, the first surface and the second surface forming one of an acute angle and an obtuse angle.

16. the plurality of light sources includes a first light source that emits light in a first wavelength range associated with a first state, and a second light source that emits light in a second wavelength range associated with a second state; 16. The projector of claim 15, wherein the first surface of the housing receives light in the first state.

17. 17. The projector of claim 16, wherein the first surface and the second surface form an acute angle.

18. 17. The projector of claim 16, wherein the first surface and the second surface form an obtuse angle.

19. The housing further comprises:

16. The projector of claim 15, including a third surface, wherein the first surface and the third surface form one of an acute angle and an obtuse angle.

20. 20. The projector of claim 19, further comprising a lens disposed at the output of the combiner.

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