Optical output system with reflectors and lenses for highly spatially uniform light output

Abstract

To provide a suitable optical output system having reflectors and lenses for highly spatially uniform optical output. [Solution] This disclosure relates to an optical output system, and more specifically to an optical output system having a reflector and a lens. In some embodiments, the optical output system may be part of an augmented and virtual reality imaging and visualization system. In some embodiments, an optical system comprising a reflector and a lens adjacent to the optical output aperture of the reflector provides an optical output with high spatial uniformity and high efficiency. The reflector is shaped to provide an optical output with substantially uniform angles, and the lens is configured to convert this angularly uniform optical output into a spatially uniform optical output. The optical output may be directed into an optical modulator that modulates light and projects an image.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the benefit of priority under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 62 / 300,742, filed on February 26, 2016, entitled “LIGHT OUTPUT SYSTEM WITH REFLECTOR AND LENS FOR HIGHLY SPATIALLY UNIFORM LIGHT OUTPUT”, the disclosure of which is hereby incorporated by reference in its entirety.

[0002] This application also incorporates by reference in its entirety U.S. Application No. 14 / 555,585, filed on November 27, 2014; U.S. Application No. 14 / 690,401, filed on April 18, 2015; U.S. Application No. 14 / 212,961, filed on March 14, 2014; and U.S. Application No. 14 / 331,218, filed on July 14, 2014.

[0003] The present disclosure relates to a light output system, and more particularly, to a light output system having a reflector and a lens. In some embodiments, the light output system may be part of an augmented and virtual reality imaging and visualization system.

Background Art

[0004] Imaging and visualization systems may utilize a system that outputs light into a light modulation device and then modulates and projects the light to form an image in the viewer's eye. There is a continuing need to develop light projection systems that can meet the requirements of modern imaging and visualization systems.

Summary of the Invention

Means for Solving the Problems

[0005] In some embodiments, an optical system is provided. The optical system comprises a reflector having an optical input aperture, an optical output aperture, and a reflective inner sidewall extending between the optical input aperture and the optical output aperture. The optical system also comprises a lens adjacent to the optical output aperture of the reflector. The sidewall of the reflector may be shaped to provide a substantially angularly uniform optical output, and the lens may be configured to convert the substantially angularly uniform optical output into a substantially spatially uniform optical output. In some embodiments, the reflector is one of an array of reflectors, each reflector having an associated lens in front of the output aperture of the reflector.

[0006] The optical system may further include an optical modulation device configured to receive light output by a reflector through a lens. The optical system may also further include a stack of waveguides, each waveguide comprising an optically coupled optical element configured to receive light from the optical modulation device. The optically coupled optical element of each waveguide may be spatially offset from the optically coupled optical elements of other waveguides so as to be seen along the propagation axis of light into the stack. The spatial arrangement of reflectors may correspond one-to-one and match with the spatial arrangement of optically coupled optical elements, as seen in the plan view. The present invention provides, for example, the following: (Item 1) An optical system, It is a reflector, Optical input aperture and Optical output aperture and A reflective inner side wall extending between the optical input aperture and the optical output aperture. A reflector comprising, A lens adjacent to the light output aperture of the reflector and An optical system equipped with [the necessary components]. (Item 2) The optical system according to item 1, further comprising an optical emitter at the optical input aperture of the reflector. (Item 3) The light source is a light-emitting diode, as described in item 2 of the optical system. (Item 4) The optical system according to item 1, wherein the reflector is one of an array of reflectors, and each reflector has an associated lens in front of the output aperture of the reflector. (Item 5) The optical system according to item 4, wherein the array of reflectors is formed by the side walls of the openings in the integrated body. (Item 6) The optical system according to item 4, wherein the reflectors form a group of reflectors, and each reflector in the group has a different length between the optical input aperture and the optical output aperture of the reflector compared to the reflectors in the other group. (Item 7) The optical system according to item 6, wherein the length of the reflectors varies depending on the wavelength of light emitted by a light source associated with each reflector. (Item 8) The optical system according to item 7, wherein the light sources associated with the reflectors form a group of light sources, each group emitting light in a different wavelength range. (Item 9) The optical system described in item 7, wherein the light source forms a group of three or more light sources. (Item 10) The optical system according to item 9, wherein the light source forms three groups of light sources, the first of which emits red light, the second of which emits green light, and the third of which emits blue light. (Item 11) The optical system according to item 4, further comprising a light modulation device configured to receive light output by the reflector through the lens. (Item 12) The optical system according to item 11, wherein the optical modulation device comprises a liquid crystal display (LCD) or a digital light processing (DLP) display. (Item 13) The optical system according to item 11, further comprising a stack of waveguides, each waveguide comprising an internally coupled optical element configured to receive light from the optical modulation device. (Item 14) The optical system according to item 13, wherein the optical internal coupling optical elements of each waveguide are spatially offset from the optical internal coupling optical elements of other waveguides so that they are seen along the propagation axis of the light into the stack. (Item 15) The optical system described in item 14, wherein the spatial arrangement of the reflectors corresponds one-to-one with the spatial arrangement of the optically coupled optical elements, as seen in the plan view. (Item 16) The optical system according to item 13, wherein each waveguide in the stack of waveguides comprises an optically externally coupled optical element configured to output light with a different amount of divergence compared to at least some of the other waveguides in the stack of waveguides. (Item 17) The side wall has a composite parabolic condenser (CPC) of a certain curvature, as seen in a cross-section obtained along a central plane extending along the height of the reflector, and the central planes are mutually orthogonal, as described in item 1. (Item 18) The optical system according to item 18, wherein the CPC curvature of two opposing internal sidewalls differs from the CPC curvature of the other internal sidewalls. (Item 19) The other internal sidewalls have the same CPC curvature as the optical system described in item 18. (Item 20) The optical system according to item 18, wherein each of the side walls has a substantially similar profile as seen in a cross-section obtained along a plane perpendicular to an axis extending along the height of the reflector. (Item 21) The optical system according to item 1, wherein the side wall extends substantially linearly from the optical input end to the optical output end. (Item 22) The optical system according to item 1, wherein the sidewall is shaped to provide a substantially angularly uniform light output, and the lens is configured to convert the substantially angularly uniform light output into a substantially spatially uniform light output. (Item 23) The reflector is the optical system according to item 1, which consists of an even number of side walls. (Item 24) The reflector is the optical system according to item 1, which has 8 or more side walls. (Item 25) The light output aperture of the reflector has a shape that is wider along the first axis than the second axis, which is the optical system according to item 1. (Item 26) The light output aperture has an elliptical shape, which is the optical system according to item 25. (Item 27) The light output aperture has a shape with a straight side along the first axis and a curved side along the second axis, which is the optical system according to item 25. (Item 28) The light output aperture and the light input aperture of the reflector have different shapes, which is the optical system according to item 25. (Item 29) The optical system according to item 1 further includes a mask in front of the reflector, the mask has a mask aperture that is aligned with the light output aperture, and the mask aperture has one or more of different shapes or different sizes from the light output aperture. (Item 30) The mask is in front of the lens, which is the optical system according to item 29.

Brief Description of Drawings

[0007] [Figure 1] Figure 1 illustrates the view of a user of augmented reality (AR) through an AR device.

[0008] [Figure 2] Figure 2 illustrates an embodiment of a wearable display system.

[0009] [Figure 3] Figure 3 illustrates a conventional display system for simulating a three - dimensional image for a user.

[0010] [Figure 4] Figure 4 illustrates aspects of an approach to simulating a 3D image using multiple depth planes.

[0011] [Figure 5] Figures 5A-5C illustrate the relationship between the radius of curvature and the radius of focus.

[0012] [Figure 6] Figure 6 illustrates an example of a waveguide stack for outputting image information to the user.

[0013] [Figure 7] Figure 7 illustrates an example of an output beam produced by a waveguide.

[0014] [Figure 8] Figure 8 illustrates an example of a stacked waveguide assembly, including an image in which each depth plane is formed using multiple different primary colors.

[0015] [Figure 9A] Figure 9A shows a cross-sectional side view of an embodiment of a stacked waveguide set, each including an internally coupled optical element.

[0016] [Figure 9B] Figure 9B shows a perspective view of an embodiment of the multiple stacked waveguides shown in Figure 9A.

[0017] [Figure 9C] Figure 9C shows top and bottom plan views of the embodiment of the multiple stacked waveguides shown in Figures 9A and 9B.

[0018] [Figure 10] Figure 10 illustrates an embodiment of a reflector having a composite parabolic concentrator (CPC) profile.

[0019] [Figure 11]Figure 11 illustrates an embodiment of an optical system having a reflector and a lens.

[0020] [Figure 12] Figure 12 illustrates an embodiment of an optical system having an optical emitter, a reflector, and a lens.

[0021] [Figure 13] Figure 13 illustrates an example of the optical output from the optical system shown in Figures 11-12.

[0022] [Figure 14A] Figures 14A-14F illustrate embodiments of reflectors having optical input and optical output apertures with different shapes. [Figure 14B] Figures 14A-14F illustrate embodiments of reflectors having optical input and optical output apertures with different shapes. [Figure 14C] Figures 14A-14F illustrate embodiments of reflectors having optical input and optical output apertures with different shapes. [Figure 14D] Figures 14A-14F illustrate embodiments of reflectors having optical input and optical output apertures with different shapes. [Figure 14E] Figures 14A-14F illustrate embodiments of reflectors having optical input and optical output apertures with different shapes. [Figure 14F] Figures 14A-14F illustrate embodiments of reflectors having optical input and optical output apertures with different shapes.

[0023] [Figure 15A] Figures 15A and 15B illustrate embodiments of the uniformity map for the optical output of the reflector shown in Figures 14A-14C and 14D-14F, respectively. [Figure 15B] Figures 15A and 15B illustrate embodiments of the uniformity map for the optical output of the reflector shown in Figures 14A-14C and 14D-14F, respectively.

[0024] [Figure 16] Figure 16 illustrates an example of a map showing the intensity of light output in angular space for the reflector shown in Figures 14A-14C in combination with the lens.

[0025] [Figure 17] Figures 17A and 17B show perspective views of embodiments of the reflector arrays shown in Figures 14A, 14C, and 14D and 14F, respectively.

[0026] [Figure 18] Figure 18 illustrates a perspective view of an embodiment of an optical system having an array of light emitters, reflectors, and lenses, and a mask.

[0027] [Figure 19] Figure 19 shows a perspective view of an embodiment of the material body having an array of reflectors and recesses for optical emitter structures such as wiring.

[0028] [Figure 20] Figures 20A-20B illustrate perspective views of embodiments of the material body having reflectors at different heights.

[0029] [Figure 21A] Figures 21A-21E illustrate various embodiments of the reflector. [Figure 21B] Figures 21A-21E illustrate various embodiments of the reflector. [Figure 21C] Figures 21A-21E illustrate various embodiments of the reflector. [Figure 21D] Figures 21A-21E illustrate various embodiments of the reflector. [Figure 21E] Figures 21A-21E illustrate various embodiments of the reflector.

[0030] [Figure 22A] Figures 22A-22B illustrate additional perspective views of the reflector shown in Figure 21. [Figure 22B]Figures 22A-22B illustrate additional perspective views of the reflector shown in Figure 21.

[0031] [Figure 22C] Figures 22C and 22D show perspective views of the reflector in Figure 21, as seen from the optical output aperture side and the optical input aperture side, respectively. [Figure 22D] Figures 22C and 22D show perspective views of the reflector in Figure 21, as seen from the optical output aperture side and the optical input aperture side, respectively.

[0032] [Figure 23A] Figures 23A and 23B illustrate embodiments of uniformity maps for the optical output of a reflector, each having a rounded profile and sharp angles at the intersections of the internal sidewalls. [Figure 23B] Figures 23A and 23B illustrate embodiments of uniformity maps for the optical output of a reflector, each having a rounded profile and sharp angles at the intersections of the internal sidewalls.

[0033] The drawings are provided to illustrate exemplary embodiments and are not intended to limit the scope of this disclosure. [Modes for carrying out the invention]

[0034] A display system can form an image by modulating light from an optical emitter and then projecting that light for viewing by a viewer. Some imaging systems can utilize an array of optical emitters, each independently supplying light to an optical modulator. Optical emitters present various challenges. For example, systems involving an array of optical emitters can be complex, with multiple structures used to direct light propagation to the optical modulator. Due to the complexity of the assembly, the system can be difficult to manufacture.

[0035] Furthermore, it should be understood that the brightness uniformity of the image formed by the display system may depend on the spatial uniformity of the light received from the light emitter by the light modulator. As a result, in order to display an image with good brightness uniformity, it is desirable that the light received by the light modulator be spatially uniform.

[0036] Advantageously, according to some embodiments, an optical system comprising a reflector and a lens adjacent to the optical output aperture of the reflector provides an optical output with high spatial uniformity and high efficiency. Preferably, the reflector is shaped to provide an optical output with substantially uniform angles, and the lens is configured to convert this angularly uniform optical output into a spatially uniform optical output. The reflector has an optical input aperture for receiving and / or absorbing light from an optical emitter and an optical output aperture for emitting the received light. In some embodiments, the optical emitter emits light with a Lambertian angular distribution. In some embodiments, the optical emitter is an extended light source, which may be, for example, a light-emitting diode. In some embodiments, the shapes of the optical input and output apertures may vary. In some embodiments, the lens is adjacent to (e.g., in front of) the optical output aperture of the reflector.

[0037] In some embodiments, the curvature of the internal reflective surface of the reflector may follow an elliptical, hyperbolic, or biconical profile, as seen in the cross-sectional side view. In some embodiments, the internal reflective surface of the reflector may have a substantially linear profile as the reflector tapers from a relatively large optical output aperture to a smaller optical input aperture. Preferably, the reflective surface of the reflector is shaped to substantially collimate a set of edge rays corresponding to a design shape or sub-aperture fixed within the emitter surface. It should be understood that more than one set of edge rays may be included in the reflector design. For example, a reflector designed to allow an axial optical emitter shift of + / -50 microns may be designed with several sets of edge rays in this range, using a reflector shape selected to substantially collimate each set. In some embodiments, the resulting shape of the reflective surface of the reflector may deviate somewhat from an idealized off-axis parabolic cross section, but may substantially resemble the shape of a composite parabolic concentrator (CPC). It should be understood that the shape and parameters of the lens and light emitter may be selected together to achieve the desired level of spatially uniform light output and efficiency.

[0038] In some embodiments, the reflective inner surface of the reflector has the profile (viewed from a cross-sectional side view) of a composite parabolic concentrator (CPC), and this profile or curvature exists in a cross-section obtained along at least two central planes extending along the height axis of the reflector, which are mutually orthogonal. It should be understood that the height of the reflector is the distance between the optical input aperture and the optical output aperture.

[0039] In some preferred embodiments, the internal surface of the reflector may have multiple sides, all of which may have a CPC profile, as seen in the side view. In addition, all internal sidewalls may be linear or flat, as seen in the cross-sectional side view obtained along a plane perpendicular to the height axis of the reflector. Thus, the internal sidewalls are considered facets, and corners may be formed at the intersections of these internal sidewalls. Preferably, these corners at the intersections of the internal sidewalls are acute, as a result of the linear nature of the sidewalls, as described above. In some embodiments, two opposing internal sidewalls may have different CPC profiles from the other internal sidewalls. In some embodiments, all of those other internal sidewalls have the same CPC profile. In some other embodiments, at least two or all of the internal sidewalls are substantially linear and extend from the optical input end to the optical output end of the reflector. Preferably, the total number of internal sidewalls is six or more, or more preferably eight or more.

[0040] In some embodiments, multiple reflectors and associated lenses form an array that provides discrete, spatially separated light sources, for example, output to an optical modulator. For example, different optical emitters may output light into each reflector and associated lens. In some embodiments, a mask may be provided in front of the lenses to provide an optical output with a desired cross-sectional shape. In some embodiments, at least some of the optical emitters may emit light of a different wavelength than the others. In some embodiments, at least some of the reflectors may have a different height than the others. In some embodiments, the reflectors, lenses, and / or masks may be formed in separate plates of material, which may later be assembled into an optical output module.

[0041] It should be understood that CPCs have traditionally been used, for example, to collect light in solar thermal collectors or to emit light in spotlight applications. While CPCs emit light with good angular uniformity, the light can form a circular shape with low light intensity inside the circular shape, especially if the CPC has a circular shape at its output aperture. Such a circular shape exhibits an unacceptably spatially non-uniform light output, which can hinder the use of CPCs for providing light in imaging systems.

[0042] However, it has been found that a highly spatially uniform light output can be provided by using a reflector with a profile that provides an angularly uniform light output in conjunction with a lens. In some embodiments, the lens utilizes the highly angularly uniform light output of the reflector and performs a Fourier transform on the light so that, after passing through the lens, the light is converted into highly spatially uniform light.

[0043] Advantageously, high spatial uniformity allows the optical output system to be used in various optical systems where highly spatially uniform optical output is desired. For example, the optical system may be a display system, and the optical output system may output light into an optical modulation device to form an image. The optical output system can also provide high efficiency, which can increase image brightness. For example, the shapes of the optical input and output surfaces may be selected to match the shapes of the optical emitter and the surface receiving the outputted light, respectively. This matching promotes high efficiency, with a very high proportion of the light from the optical emitter reaching the receiving surface. In addition, the reflectors may be formed in an integrated body of one or more materials, which can offer the advantage of simplifying manufacturing and providing a compact structure while blocking light leakage between reflectors. In addition, other associated structures such as mask openings may also be formed in an integrated body that can be overlaid on the reflectors, which can simplify the manufacturing of those structures and their subsequent assembly into the integrated optical system. In some embodiments, the reflectors and lenses are configured to achieve 4-D photoforming.

[0044] Here, we refer to the diagram, where similar reference numbers refer to the same features throughout.

[0045] Referring to Figure 1, Augmented Reality Scene 1 is depicted. Modern computing and display technologies are accelerating the development of systems for so-called "virtual reality" or "augmented reality" experiences, in which digitally reproduced images or parts thereof are presented to the user in a manner that appears to be real, or can be perceived as such. Virtual reality or "VR" scenarios typically involve the presentation of digital or virtual image information without transparency to other real-world visual inputs, while augmented reality or "AR" scenarios typically involve the presentation of digital or virtual image information as an extension to the visualization of the real world around the user. Mixed reality or "MR" scenarios are a type of AR scenario that typically involves virtual objects integrated into and responding to the natural world. For example, an MR scenario may include AR image content that appears blocked by or is perceived to interact with objects in the real world in a different way. Figure 1 illustrates Augmented Reality Scene 1, in which the user of the AR technology sees a real-world park-like setting 20 featuring people, trees, and buildings in the background, and a concrete platform 30. The user also perceives that they are "seeing" "virtual content," such as a robotic figure 40 standing on a real-world platform 1120 and a flying, cartoonish avatar character 50 that looks like a personification of a bumblebee. These elements 50 and 40 are "virtual" in that they do not exist in the real world. The human visual perception system is complex, and generating AR technology that facilitates a comfortable, natural, and rich presentation of virtual image elements among other virtual or real-world image elements is difficult.

[0046] Figure 2 illustrates an embodiment of a wearable display system 60. The display system 60 includes a display 70 and various mechanical and electronic modules and systems to support the functions of the display 70. The display 70 may be coupled to a frame 80, which is wearable by a display system user or viewer 90 and is configured to position the display 70 in front of the user 90's eyes. In some embodiments, the display 70 may be considered eyewear. In some embodiments, a speaker 100 is coupled to the frame 80 and is configured to be positioned adjacent to the user 90's ear canal (in some embodiments, another speaker, not shown, may optionally be positioned adjacent to the user's other ear canal to provide stereo / shapeable sound control). The display system may also include one or more microphones 110 or other devices to detect sound. In some embodiments, the microphone may be configured to allow the user to provide input or commands to the system 60 (e.g., selection of voice menu commands, natural language questions, etc.) and / or enable audio communication with other persons (e.g., other users of a similar display system). The microphone may further be configured as a peripheral sensor to collect audio data (e.g., sounds from the user and / or the environment). In some embodiments, the display system may also include a peripheral sensor 120a, which is separate from the frame 80 and may be mounted on the user 90's body (e.g., on the user 90's head, torso, limbs, etc.). In some embodiments, the peripheral sensor 120a may be configured to acquire data characterizing the user 90's physiological state. For example, the sensor 120a may be an electrode.

[0047] Continuing with Figure 2, the display 70 is operably coupled to the local data processing module 140 by a communication link 130, such as a wired connection or wireless connectivity, which may be mounted in various configurations, such as being fixedly attached to the frame 80, fixedly attached to a helmet or hat worn by the user, embedded in headphones, or otherwise removable by the user 90 (e.g., in a backpack configuration, a belt-mounted configuration). Similarly, the sensor 120a may be operably coupled to the local processor and data module 140 by a communication link 120b, such as a wired connection or wireless connectivity. The local processing and data module 140 may include a hardware processor and digital memory such as non-volatile memory (e.g., flash memory or a hard disk drive), both of which may be used to assist in data processing, caching, and storage. The data includes a) data captured from sensors such as image capture devices (cameras, etc.), microphones, inertial measurement units, accelerometers, compasses, GPS units, wireless devices, gyroscopes, and / or other sensors disclosed herein (e.g., operably coupled to frame 80 or otherwise attached to user 90), and / or b) data acquired and / or processed using the remote processing module 150 and / or remote data repository 160 (including data related to virtual content) for passage to display 70 after such processing or reading, possibly. The local processing and data module 140 may be operably coupled to the remote processing module 150 and the remote data repository 160 by communication links 170, 180, such as via wired or wireless communication links, so that these remote modules 150, 160 are operably coupled to each other and available as resources to the local processing and data module 140.In some embodiments, the local processing and data module 140 may include one or more of the following: an image acquisition device, a microphone, an inertial measurement unit, an accelerometer, a compass, a GPS unit, a wireless device, and / or a gyroscope. In some other embodiments, one or more of these sensors may be mounted on the frame 80 or may be a standalone structure communicating with the local processing and data module 140 via a wired or wireless communication path.

[0048] Continuing with Figure 2, in some embodiments, the remote processing module 150 may comprise one or more processors configured to analyze and process data and / or image information. In some embodiments, the remote data repository 160 may comprise digital data storage facilities that may be available through the internet or other networking configurations in a “cloud” resource configuration. In some embodiments, the remote data repository 160 may comprise one or more remote servers that provide information, for example, information for generating augmented reality content, to the local processing and data module 140 and / or the remote processing module 150. In some embodiments, all data is stored and all calculations are performed within the local processing and data module, enabling fully autonomous use from the remote module.

[0049] Referring here to Figure 3, the perception of an image as "three-dimensional" or "3-D" can be achieved by providing slightly different presentations of the image to each eye of the viewer. Figure 3 illustrates a conventional display system for simulating a three-dimensional image with respect to a user. Two distinctly different images 190, 200, one for each eye 210, 220, are output to the user. Images 190, 200 are spaced only 230 units apart from eyes 210, 220 along an optical axis or z-axis parallel to the viewer's line of sight. Images 190, 200 are flat, and eyes 210, 220 can focus on the image by taking a single perspective-accommodated state. Such a 3-D display system relies on the human visual system, combines images 190, 200, and provides a perception of depth and / or scale of the combined image.

[0050] However, it should be understood that the human visual system is more complex and providing a realistic perception of depth is more difficult. For example, many viewers of conventional "3-D" display systems may find such systems uncomfortable or may not perceive any sense of depth at all. While not limited by theory, it is thought that viewers of objects may perceive them as "three-dimensional" due to a combination of convergence and divergence movements and accommodation. The convergence and divergence movements of two eyes relative to each other (i.e., the rotation of the eyes, where the pupils move toward or away from each other to converge the lines of sight of the eyes and fix them on an object) are closely related to the focusing (or "accommodation") of the eye's lens and pupil. Under normal conditions, changing the focus of the eye's lens, or adjusting the eye to focus from one object to another at a different distance, will automatically produce consistent changes in convergence and divergence up to the same distance, under the relationship known as the "accommodation-convergence-divergence reflex" and pupil dilation or constriction. Similarly, changes in convergence and divergence will, under normal conditions, induce consistent changes in accommodative lens shape and pupil size. As described herein, many stereoscopic or "3-D" display systems display a scene using slightly different presentations (and therefore slightly different images) to each eye so that a three-dimensional viewpoint is perceived by the human visual system. However, such systems, among other things, simply provide different presentations of the scene, but are uncomfortable for many viewers because they function against the "accommodation-convergence-divergence reflex" when the eye views all image information in a single accommodated state. Display systems that provide better coordination between accommodation and convergence and divergence can form a more realistic and comfortable simulation of three-dimensional images.

[0051] Figure 4 illustrates aspects of an approach to simulating a three-dimensional image using multiple depth planes. Referring to Figure 4, objects at various distances from eyes 210, 220 on the z-axis are accommodated by eyes 210, 220 so that those objects are in focus. Eyes 210, 220 take on specific accommodated states to focus on objects at different distances along the z-axis. As a result, a specific accommodated state can be associated with one of the depth planes 240 having an associated focal length such that an object or part of an object in a particular depth plane is in focus when the eye is in the accommodated state for that depth plane. In some embodiments, the three-dimensional image may be simulated by providing a different presentation of the image for each eye 210, 220, and by providing a different presentation of the image corresponding to each depth plane. For the sake of clarity in the illustration, it should be understood that the fields of view of eyes 210, 220 may overlap, for example, as the distance along the z-axis increases, although they are shown as separate. Furthermore, for the sake of illustration, although shown as flat, it should be understood that the contour of the depth plane can be curved in physical space so that all features within the depth plane are in focus with the eye in a particular state of perspective adjustment.

[0052] The distance between an object and the eye 210 or 220 can also change the amount of light diverging from that object as visible to that eye. Figures 5A-5C illustrate the relationship between distance and ray divergence. The distance between the object and the eye 210 is expressed in the order of decreasing distances R1, R2, and R3. As shown in Figures 5A-5C, the ray diverges more as the distance to the object decreases. As the distance increases, the ray becomes more collimated. In other words, the light field produced by a point (object or part of an object) can be said to have a spherical wavefront curvature, which is a function of the distance the point is from the user's eye. The curvature increases with decreasing distance between the object and the eye 210. Consequently, in different depth planes, the ray divergence is also different, and the divergence increases with decreasing distance between the depth plane and the viewer's eye 210. Only a single eye 210 is illustrated in Figures 5A–5C and other figures herein for the sake of clarity in the illustration; however, it should be understood that the discussion relating to eye 210 may apply to both eyes 210 and 220 of the viewer.

[0053] While not limited by theory, the human eye is typically thought to be capable of interpreting a finite number of depth planes and providing depth perception. Consequently, a highly realistic simulation of perceived depth can be achieved by providing the eye with different presentations of images corresponding to each of these limited number of depth planes. These different presentations may be used to provide depth cues to the user based on the eye's accommodation required to focus on different image features for scenes located on different depth planes, and / or based on the observation of different image features on different depth planes that are out of focus.

[0054] Figure 6 illustrates an embodiment of a waveguide stack for outputting image information to a user. The display system 250 includes a waveguide stack or stacked waveguide assembly 260, which may be used to provide three-dimensional perception to the eye / brain using a plurality of waveguides 270, 280, 290, 300, 310. In some embodiments, the display system 250 is the system 60 in Figure 2, and Figure 6 shows some parts of that system 60 in more detail. For example, the waveguide assembly 260 may be part of the display 70 in Figure 2. It should be understood that the display system 250 may be considered a light field display in some embodiments. In addition, the waveguide assembly 260 may also be referred to as an eyepiece.

[0055] Continuing with Figure 6, the waveguide assembly 260 may also include several features 320, 330, 340, and 350 between the waveguides. In some embodiments, features 320, 330, 340, and 350 may be one or more lenses. Waveguides 270, 280, 290, 300, and 310 and / or multiple lenses 320, 330, 340, and 350 may be configured to transmit image information to the eye using varying levels of wavefront curvature or ray divergence. Each waveguide level may be associated with a specific depth plane and may be configured to output image information corresponding to that depth plane. Image input devices 360, 370, 380, 390, and 400 may function as light sources for the waveguides and may be used to input image information into waveguides 270, 280, 290, 300, and 310, and each may be configured to disperse incident light across each individual waveguide for output toward the eye 210, as described herein. The light exits from the output surfaces 410, 420, 430, 440, and 450 of image input devices 360, 370, 380, 390, and 400 and is input into the corresponding input surfaces 460, 470, 480, 490, and 500 of waveguides 270, 280, 290, 300, and 310. In some embodiments, the input surfaces 460, 470, 480, 490, and 500 may each be the edge of the corresponding waveguide or a portion of the main surface of the corresponding waveguide (i.e., one of the waveguide surfaces that directly faces the world 510 or the viewer's eye 210). In some embodiments, a single beam of light (e.g., a collimated beam) may be injected into each waveguide to output a whole field of cloned collimated beams, which are directed toward the eye 210 at a specific angle (and divergence) corresponding to the depth plane associated with the particular waveguide. In some embodiments, one of the image input devices 360, 370, 380, 390, and 400 may be associated with a plurality (e.g., three) of waveguides 270, 280, 290, 300, and 310 to injected light into them.

[0056] In some embodiments, the image input devices 360, 370, 380, 390, and 400 are discrete displays that generate image information for input into the corresponding waveguides 270, 280, 290, 300, and 310, respectively. In some other embodiments, the image input devices 360, 370, 380, 390, and 400 are output terminals of a single multiplexed display that can send image information to each of the image input devices 360, 370, 380, 390, and 400 via, for example, one or more optical conduits (such as optical fiber cables). It should be understood that the image information provided by the image input devices 360, 370, 380, 390, and 400 may include light of different wavelengths or colors (e.g., different primary colors, as discussed herein).

[0057] In some embodiments, the light introduced into waveguides 270, 280, 290, 300, and 310 is provided by an optical projector system 520, which comprises an optical module 540, which may include an optical emitter such as a light-emitting diode (LED). The light from the optical module 540 may be directed and modified via a beam splitter 550 by an optical modulator 530, such as a spatial light modulator. The optical modulator 530 may be configured to change the perceived intensity of the light introduced into waveguides 270, 280, 290, 300, and 310. Embodiments of the spatial light modulator include liquid crystal displays (LCDs), including liquid crystal on silicon (LCOS) displays. Image input devices 360, 370, 380, 390, and 400 are graphically illustrated, and it should be understood that in some embodiments, these image input devices may represent different optical paths and locations within a common projection system, configured to output light into associated waveguides 270, 280, 290, 300, and 310.

[0058] In some embodiments, the display system 250 may be a scanning fiber display comprising one or more scanning fibers configured to project light in various patterns (e.g., raster scanning, helical scanning, Lissajous patterns, etc.) into one or more waveguides 270, 280, 290, 300, 310, ultimately to the viewer's eye 210. In some embodiments, the illustrated image input devices 360, 370, 380, 390, 400 may schematically represent a single scanning fiber or a bundle of scanning fibers configured to input light into one or more waveguides 270, 280, 290, 300, 310. In some other embodiments, the illustrated image input devices 360, 370, 380, 390, 400 may schematically represent a plurality of scanning fibers or a plurality of bundles of scanning fibers, each configured to input light into one of the associated waveguides 270, 280, 290, 300, 310. It should be understood that one or more optical fibers may be configured to transmit light from the optical module 540 to one or more waveguides 270, 280, 290, 300, 310. It should be understood that one or more intervening optical structures may be provided between the scanning fiber or multiple fibers and one or more waveguides 270, 280, 290, 300, 310, for example, to redirect light emanating from the scanning fiber into one or more waveguides 270, 280, 290, 300, 310.

[0059] The controller 560 controls the operation of one or more of the stacked waveguide assemblies 260, including the operation of the image input devices 360, 370, 380, 390, 400, the light source 540, and the optical module 530. In some embodiments, the controller 560 is part of the local data processing module 140. The controller 560 includes programming (e.g., instructions in a non-transient medium) to coordinate the timing and provisioning of image information to the waveguides 270, 280, 290, 300, 310, for example, according to one of the various schemes disclosed herein. In some embodiments, the controller may be a single integrated device or a distributed system connected by wired or wireless communication channels. In some embodiments, the controller 560 may be part of the processing module 140 or 150 (Figure 2).

[0060] Continuing with Figure 6, the waveguides 270, 280, 290, 300, and 310 may be configured to propagate light within each individual waveguide by total internal reflection (TIR). Each waveguide 270, 280, 290, 300, and 310 may be planar or have another shape (e.g., curved), with major upper and lower surfaces and edges extending between their major upper and lower surfaces. In the illustrated configuration, each waveguide 270, 280, 290, 300, and 310 may include external coupling optical elements 570, 580, 590, 600, and 610, respectively, configured to extract light from the waveguides by redirecting the light, propagating it within each individual waveguide, and outputting image information from the waveguides to the eye 210. The extracted light may also be referred to as externally coupled light, and the optical elements that externally couple the light may also be referred to as light extraction optical elements. The extracted beam of light can be output by the waveguide at the point where light propagating within the waveguide strikes the light extraction optical element. The external coupling optical elements 570, 580, 590, 600, 610 may be gratings, for example, including diffractive optical features as further discussed herein. For the sake of clarity and to facilitate the explanation, they are shown positioned on the bottom main surfaces of the waveguides 270, 280, 290, 300, 310, but in some embodiments, the external coupling optical elements 570, 580, 590, 600, 610 may be positioned on the top and / or bottom main surfaces, as further discussed herein, and / or directly within the volume of the waveguides 270, 280, 290, 300, 310. In some embodiments, the external coupling optical elements 570, 580, 590, 600, 610 may be mounted on a transparent substrate and formed within a layer of material that forms the waveguides 270, 280, 290, 300, 310. In some other embodiments, the waveguides 270, 280, 290, 300, 310 may be monolithic material pieces, and the external coupling optical elements 570, 580, 590, 600, 610 may be formed on and / or inside the material piece.

[0061] Continuing with reference to Figure 6, as discussed herein, each waveguide 270, 280, 290, 300, 310 is configured to emit light and form an image corresponding to a specific depth plane. For example, the waveguide 270 closest to the eye may be configured to deliver collimated light (injected into such waveguide 270) to the eye 210. The collimated light may represent the optical infinity focal plane. The next upper waveguide 280 may be configured to emit collimated light that passes through a first lens 350 (e.g., a negative lens) before reaching the eye 210. Such a first lens 350 may generate some convex wavefront curvature so that the eye / brain interprets the light originating from the next upper waveguide 280 as originating from a first focal plane closer inward from optical infinity toward the eye 210. Similarly, the third upper waveguide 290 passes its output light through both the first lens 350 and the second lens 340 before reaching the eye 210. The combined refractive power of the first lens 350 and the second lens 340 may be configured to generate another incremental amount of wavefront curvature so that the eye / brain interprets the light originating from the third waveguide 290 as originating from a second focal plane that is closer inward toward the person from optical infinity than the light originating from the next upper waveguide 280.

[0062] Similarly, the other waveguide layers 300, 310 and lenses 330, 320 are configured such that the highest waveguide 310 in the stack transmits its output through all the lenses between it and the eye for a convergent focusing force representing the focal plane closest to the person. When viewing / interpreting light originating from the other side world 510 of the stacked waveguide assembly 260, a compensating lens layer 620 may be positioned on top of the stack to compensate for the convergent force of the lower lens stacks 320, 330, 340, 350 to compensate for the stack of lenses 320, 330, 340, 350. Such a configuration provides the same number of perceived focal planes as there are available waveguide / lens pairs. Both the external coupling optical elements of the waveguides and the focusing sides of the lenses may be static (i.e., not dynamic or electroactive). In some alternative embodiments, either or both may be dynamic using electroactive features.

[0063] In some embodiments, two or more of the waveguides 270, 280, 290, 300, and 310 may have the same associated depth plane. For example, a plurality of waveguides 270, 280, 290, 300, and 310 may be configured to output images set in the same depth plane, or a plurality of subsets of waveguides 270, 280, 290, 300, and 310 may be configured to output images set in the same plurality of depth planes, with one set for each depth plane. This may offer the advantage of forming images that are tiled to provide an extended field of view in those depth planes.

[0064] Continuing with Figure 6, the external coupling optical elements 570, 580, 590, 600, and 610 may be configured to both redirect light from their respective waveguides for specific depth planes associated with the waveguides and to output the light with an appropriate amount of divergence or collimation. As a result, waveguides with different associated depth planes may have different configurations of the external coupling optical elements 570, 580, 590, 600, and 610, which output light with different amounts of divergence depending on the associated depth plane. In some embodiments, the light extraction optical elements 570, 580, 590, 600, and 610 may be volumetric or surface features, which may be configured to output light at specific angles. For example, the light extraction optical elements 570, 580, 590, 600, and 610 may be volumetric holograms, surface holograms, and / or diffraction gratings. In some embodiments, features 320, 330, 340, and 350 may not be lenses. Rather, they may simply be spacers (e.g., structures for forming cladding layers and / or voids).

[0065] In some embodiments, the external coupling optical elements 570, 580, 590, 600, and 610 are diffractive features that form a diffraction pattern or “diffractive optical element” (also referred to herein as “DOE”). Preferably, the DOE has a sufficiently low diffraction efficiency such that only a portion of the beam light is deflected toward the eye 210 through each intersection of the DOE, while the remainder continues to travel through the waveguide via the TIR. The light carrying the image information is therefore split into several associated emission beams that exit the waveguide at various locations, resulting in a very uniform pattern of emission toward the eye 210 with respect to this particular collimated beam bouncing within the waveguide.

[0066] In some embodiments, one or more DOEs may be switchable between an "on" state in which they actively diffract and an "off" state in which they do not significantly diffract. For example, a switchable DOE may comprise a layer of polymer-dispersed liquid crystal, in which microdroplets have a diffraction pattern in the host medium, and the refractive index of the microdroplets may be switched to substantially match the refractive index of the host material (in which case the pattern does not significantly diffract incident light), or the microdroplets may be switched to a refractive index that does not match that of the host medium (in which case the pattern actively diffracts incident light).

[0067] In some embodiments, a camera assembly 630 (e.g., a digital camera including visible light and infrared light cameras) may be provided to capture images of the eye 210 and / or the surrounding tissues, for example, to detect user input and / or monitor the user's physiological state. As used herein, the camera may be any image-capturing device. In some embodiments, the camera assembly 630 may include the image-capturing device and a light source that projects light (e.g., infrared light) onto the eye, which is then reflected by the eye and can be detected by the image-capturing device. In some embodiments, the camera assembly 630 may be mounted on a frame 80 (Figure 2) and may communicate with processing modules 140 and / or 150 that can process image information from the camera assembly 630. In some embodiments, one camera assembly 630 may be used per eye to monitor each eye separately.

[0068] Referring here to Figure 7, an embodiment of an outgoing beam output by a waveguide is shown. Although one waveguide is illustrated, other waveguides within the waveguide assembly 260 (Figure 6) may function similarly, and it should be understood that the waveguide assembly 260 includes multiple waveguides. Light 640 is introduced into the waveguide 270 at the input surface 460 of the waveguide 270 and propagates through the waveguide 270 by TIR. At the point where the light 640 collides on the DOE 570, a portion of the light exits the waveguide as an outgoing beam 650. The outgoing beam 650 is illustrated as substantially parallel, but may be redirected to propagate to the eye 210 at a certain angle (e.g., forming a divergent outgoing beam), depending on the depth plane associated with the waveguide 270, as discussed herein. It should be understood that a nearly parallel emitted beam may represent a waveguide with an external coupling optical element that externally couples the light to form an image that appears to be set in the depth plane at a distance from the eye 210 (e.g., optical infinity). Other waveguides or other sets of external coupling optical elements may output a more divergent emitted beam pattern, which would require the eye 210 to adjust to a closer distance and focus on the retina, and would be interpreted by the brain as light from a distance closer to the eye 210 than optical infinity.

[0069] In some embodiments, a full-color image may be formed in each depth plane by overlaying an image onto each of the primary colors, for example, three or more primary colors. Figure 8 illustrates an embodiment of a stacked waveguide assembly, where each depth plane includes an image formed using several different primary colors. The illustrated embodiment shows depth planes 240a–240f, but more or fewer depths are also considered. Each depth plane may have three or more associated primary color images, including a first image of a first color G, a second image of a second color R, and a third image of a third color B. Different depth planes are indicated in the figure by different numbers relating to diopters (dpt) following the letters G, R, and B. As merely an embodiment, the numbers following each of these letters indicate diopters (1 / m), i.e., the inverse distance of the depth plane from the viewer, and each box in the figure represents an individual primary color image. In some embodiments, the precise location of the depth plane for different primary colors may vary to account for differences in the focusing of light of different wavelengths in the eye. For example, different primary color images for a given depth plane may be placed on depth planes corresponding to different distances from the user. Such arrangements may increase visual acuity and user comfort and / or reduce chromatic aberration.

[0070] In some embodiments, each primary color light may be output by a single dedicated waveguide, and as a result, each depth plane may have multiple waveguides associated with it. In such embodiments, each box in the figure, including the letters G, R, or B, can be understood to represent an individual waveguide, and three waveguides may be provided for each depth plane, and three primary color images are provided for each depth plane. The waveguides associated with each depth plane are shown adjacent to each other in this drawing for ease of explanation, but it should be understood that in a physical device, all waveguides may be arranged in a stack with one waveguide per level. In some other embodiments, multiple primary colors may be output by the same waveguide, for example, so that only a single waveguide may be provided for each depth plane.

[0071] Continuing to refer to Figure 8, in some embodiments, G is green, R is red, and B is blue. In some other embodiments, other colors associated with other wavelengths of light, including magenta and cyan, may also be used, or may replace one or more of red, green, or blue.

[0072] Throughout this disclosure, any reference to a given color of light should be understood as encompassing light of one or more wavelengths within the range of wavelengths of light that are perceived by the viewer as that given color. For example, red light may include light of one or more wavelengths within the range of approximately 620–780 nm, green light may include light of one or more wavelengths within the range of approximately 492–577 nm, and blue light may include light of one or more wavelengths within the range of approximately 435–493 nm.

[0073] In some embodiments, the light source 540 (Figure 6) may be configured to emit light of one or more wavelengths outside the viewer's visual perception range, such as infrared and / or ultraviolet wavelengths. In addition, internal coupling, external coupling, and other light redirection structures of the waveguide of the display 250 may be configured to direct and emit this light from the display toward the user's eye 210, for example, for imaging and / or user stimulation applications.

[0074] Referring here to Figure 9A, in some embodiments, light impacting a waveguide may need to be redirected to internally couple that light into the waveguide. Internal coupling optical elements may be used to redirect and internally couple the light into its corresponding waveguide. Figure 9A illustrates a cross-sectional side view of an embodiment of multiple or set 660 stacked waveguides, each containing an internal coupling optical element. Each waveguide may be configured to output light of one or more different wavelengths or one or more different wavelength ranges. Stack 660 may correspond to stack 260 (Figure 6), and the illustrated waveguides of stack 660 may correspond to some of the multiple waveguides 270, 280, 290, 300, 310, but it should be understood that light from one or more of the image input devices 360, 370, 380, 390, 400 is input into the waveguide from a position where the light is required to be redirected for internal coupling.

[0075] The illustrated set of stacked waveguides 660 includes waveguides 670, 680, and 690. Each waveguide includes associated internal coupling optical elements (which may also be referred to as optical input areas on the waveguide), for example, internal coupling optical element 700 is located on the main surface of waveguide 670 (e.g., the upper main surface), internal coupling optical element 710 is located on the main surface of waveguide 680 (e.g., the upper main surface), and internal coupling optical element 720 is located on the main surface of waveguide 690 (e.g., the upper main surface). In some embodiments, one or more of the internal coupling optical elements 700, 710, and 720 may be located on the bottom main surfaces of the individual waveguides 670, 680, and 690 (in particular, one or more internal coupling optical elements are reflective deflection optical elements). As illustrated, the internally coupled optical elements 700, 710, and 720 may be located on the upper main surface of their respective waveguides 670, 680, and 690 (or on the upper part of the following lower waveguide), and in particular, these internally coupled optical elements are transmissive deflection optical elements. In some embodiments, the internally coupled optical elements 700, 710, and 720 may be located within the body of the respective waveguides 670, 680, and 690. In some embodiments, as discussed herein, the internally coupled optical elements 700, 710, and 720 are wavelength-selective, selectively redirecting one or more wavelengths of light while transmitting other wavelengths of light. Although illustrated on one side or corner of their respective waveguides 670, 680, and 690, it should be understood that in some embodiments, the internally coupled optical elements 700, 710, and 720 may be located within other areas of their respective waveguides 670, 680, and 690.

[0076] As illustrated, the internally coupled optical elements 700, 710, and 720 may be offset laterally from one another. In some embodiments, each internally coupled optical element may be offset so that its light does not pass through another internally coupled optical element to receive light. For example, each internally coupled optical element 700, 710, and 720 may be configured to receive light from different image input devices 360, 370, 380, 390, and 400, as shown in Figure 6, and may be separated from other internally coupled optical elements 700, 710, and 720 (e.g., separated laterally) so that it does not substantially receive light from the other internally coupled optical elements 700, 710, and 720.

[0077] Each waveguide also includes associated optical dispersion elements, for example, optical dispersion element 730 is located on the main surface (e.g., upper main surface) of waveguide 670, optical dispersion element 740 is located on the main surface (e.g., upper main surface) of waveguide 680, and optical dispersion element 750 is located on the main surface (e.g., upper main surface) of waveguide 690. In some other embodiments, optical dispersion elements 730, 740, and 750 may be located on the bottom main surfaces of the associated waveguides 670, 680, and 690, respectively. In some other embodiments, optical dispersion elements 730, 740, and 750 may be located on both the top and bottom main surfaces of the associated waveguides 670, 680, and 690, respectively, or optical dispersion elements 730, 740, and 750 may be located on different top and bottom main surfaces within different associated waveguides 670, 680, and 690, respectively.

[0078] Waveguides 670, 680, and 690 may be separated and isolated by, for example, gaseous, liquid, and / or solid layers of material. For example, as shown, layer 760a may separate waveguides 670 and 680, and layer 760b may separate waveguides 680 and 690. In some embodiments, layers 760a and 760b are formed from a low refractive index material (i.e., a material having a lower refractive index than the material forming the immediate vicinity of waveguides 670, 680, and 690). Preferably, the refractive index of the material forming layers 760a and 760b is 0.05 or greater, or 0.10 or less, than the refractive index of the material forming waveguides 670, 680, and 690. Advantageously, lower refractive index layers 760a, 760b may function as cladding layers that facilitate total internal reflection (TIR) ​​of light through waveguides 670, 680, 690 (e.g., TIR between the upper and lower main surfaces of each waveguide). In some embodiments, layers 760a, 760b are formed from air. It should be understood that the upper and lower parts of the illustrated set 660 waveguides may also include immediate cladding layers, although these are not shown.

[0079] Preferably, to facilitate manufacturing and other considerations, the materials forming waveguides 670, 680, and 690 are similar or identical, and the materials forming layers 760a and 760b are similar or identical. In some embodiments, the materials forming waveguides 670, 680, and 690 may differ between one or more waveguides, and / or the materials forming layers 760a and 760b may differ, while still maintaining the various refractive index relationships described above.

[0080] Continuing to refer to Figure 9A, rays 770, 780, and 790 are incident on set of waveguides 660. It should be understood that rays 770, 780, and 790 may also be injected into waveguides 670, 680, and 690 by one or more imaging devices 360, 370, 380, 390, and 400 (Figure 6).

[0081] In some embodiments, the rays 770, 780, and 790 may have different properties, such as different wavelengths or different wavelength ranges, which may correspond to different colors. The internal coupling optical elements 700, 710, and 720 each deflect the incident light so that the light propagates through one of the waveguides 670, 680, and 690 by TIR. In some embodiments, the internal coupling optical elements 700, 710, and 720 each selectively deflect one or more specific wavelengths of light while allowing other wavelengths to pass through the lower waveguide and associated internal coupling optical elements.

[0082] For example, the internally coupled optical element 700 may be configured to selectively deflect a ray 770 having a first wavelength or wavelength range while transmitting rays 780 and 790 having different second and third wavelengths or wavelength ranges, respectively. The transmitted ray 780 collides with an internally coupled optical element 710 configured to deflect light of the second wavelength or wavelength range, and is deflected by it. The ray 790 is deflected by an internally coupled optical element 720 configured to selectively deflect light of the third wavelength or wavelength range.

[0083] Continuing with Figure 9A, the deflected rays 770, 780, and 790 are deflected so that they propagate through the corresponding waveguides 670, 680, and 690. That is, the internal coupling optical elements 700, 710, and 720 of each waveguide deflect the light into its corresponding waveguide 670, 680, and 690, and internally couple the light into the corresponding waveguide. The rays 770, 780, and 790 are deflected at an angle that causes the light to propagate through the individual waveguides 670, 680, and 690 by TIR. The rays 770, 780, and 790 propagate through the individual waveguides 670, 680, and 690 by TIR until they collide with the corresponding optical dispersion elements 730, 740, and 750 of the waveguide.

[0084] Referring now to Figure 9B, a perspective view of an embodiment of the multiple stacked waveguides shown in Figure 9A is illustrated. As previously mentioned, the internally coupled rays 770, 780, and 790 are deflected by the internally coupled optical elements 700, 710, and 720, respectively, and then propagate by TIR within waveguides 670, 680, and 690, respectively. The rays 770, 780, and 790 then collide with the optical dispersion elements 730, 740, and 750, respectively. The optical dispersion elements 730, 740, and 750 deflect the rays 770, 780, and 790 so that they propagate toward the externally coupled optical elements 800, 810, and 820, respectively.

[0085] In some embodiments, the light dispersion elements 730, 740, and 750 are orthogonal pupil expanders (OPEs). In some embodiments, the OPEs deflect or disperse light to the external coupling optical elements 800, 810, and 820, and in some embodiments, they may also increase the beam or spot size of the light as it propagates to the external coupling optical elements. In some embodiments, the light dispersion elements 730, 740, and 750 may be omitted, and the internal coupling optical elements 700, 710, and 720 may be configured to deflect light directly to the external coupling optical elements 800, 810, and 820. For example, referring to Figure 9A, the light dispersion elements 730, 740, and 750 may be replaced by the external coupling optical elements 800, 810, and 820, respectively. In some embodiments, the external coupling optical elements 800, 810, 820 are exit pupils (EPs) or exit pupil expanders (EPEs) that direct light towards the viewer's eye 210 (Figure 7). It should be understood that the OPEs may be configured to increase the dimensions of the eyebox along at least one axis, and the EPEs may increase the eyebox along axes that intersect with the axes of the OPEs, for example, orthogonal axes. For example, each OPE may be configured to redirect a portion of the light impacting the OPE to an EPE in the same waveguide, while allowing the rest of the light to continue propagating along the waveguide. In response to the impact on the OPE, another portion of the remaining light is again redirected to the EPE, and the rest of that portion continues to propagate further along the waveguide, etc. Similarly, in response to the impact on the EPE, a portion of the impacting light is directed out of the waveguide towards the user, and the rest of that light continues to propagate through the waveguide until it impacts the EP again, at which point another portion of the impacting light is directed out of the waveguide, and so on. As a result, the internally coupled single beam of light is "duplicated" each time a portion of its light is redirected by the OPE or EPE, thereby forming a cloned beam field of light, as shown in Figure 6. In some embodiments, the OPE and / or EPE may be configured to modify the size of the beam of light.

[0086] Therefore, referring to Figures 9A and 9B, in some embodiments, the set of waveguides 660 includes, for each primary color, waveguides 670, 680, 690, internally coupled optical elements 700, 710, 720, optical dispersion elements (e.g., OPE) 730, 740, 750, and externally coupled optical elements (e.g., EP) 800, 810, 820. Waveguides 670, 680, 690 may be stacked with air gaps / cladding layers between each one. The internally coupled optical elements 700, 710, 720 redirect or deflect the incident light into their waveguides (using different internally coupled optical elements that receive light of different wavelengths). The light then propagates within the individual waveguides 670, 680, 690 at angles that will result in a TIR. In the embodiment shown, a ray 770 (e.g., blue light) is polarized by the first internally coupled optical element 700 in the manner described above, and then continues to bounce along the waveguide, interacting with the optical dispersion element (e.g., OPE) 730 and then the externally coupled optical element (e.g., EP) 800. Rays 780 and 790 (e.g., green and red light, respectively) pass through waveguide 670, with ray 780 incident on internally coupled optical element 710, where it is deflected. Ray 780 will then bounce along waveguide 680 via TIR, proceeding to its optical dispersion element (e.g., OPE) 740 and then the externally coupled optical element (e.g., EP) 810. Finally, ray 790 (e.g., red light) passes through waveguide 690 and collides with the internally coupled optical element 720 of waveguide 690. The internal optical coupling element 720 deflects the ray 790 so that it propagates by TIR to the optical dispersion element (e.g., OPE) 750, and then by TIR to the external coupling element (e.g., EP) 820. The external coupling element 820 then finally couples the ray 790 to the viewer, who also receives light from the other waveguides 670 and 680.

[0087] Figure 9C illustrates upper and lower plan views of embodiments of the multiple stacked waveguides shown in Figures 9A and 9B. As shown, waveguides 670, 680, and 690 may be vertically aligned with their associated optical dispersion elements 730, 740, and 750 and associated external coupling optical elements 800, 810, and 820. However, as discussed herein, the internal coupling optical elements 700, 710, and 720 are not vertically aligned. Rather, the internal coupling optical elements are preferably non-overlapping (e.g., laterally spaced, as seen in the upper and lower figures). As further discussed herein, this non-overlapping spatial arrangement facilitates the ingress of light from different resources into different waveguides on a one-to-one basis, thereby enabling a specific light source to be uniquely coupled to a specific waveguide. In some embodiments, arrangements including non-overlapping, spatially separated internal coupling optical elements may be referred to as pupil-shifting systems, where the internal coupling optical elements in these arrangements may correspond to subpupils.

[0088] In some embodiments, light from an optical emitter is shaped using a reflector and lenses. Figure 10 illustrates an embodiment of a reflector 2000 having the profile of a composite parabolic concentrator (CPC). The reflector 2000 has an optical input aperture 2002 and an optical output aperture 2004, both of which may be circular. The optical input aperture may receive light (e.g., rays 2010, 2020, 2030) from an optical emitter (not shown). The light is reflected from the wall 2040 of the reflector and exits the reflector 2000 through the optical output aperture 2004. Notably, the output rays 2010, 2020, 2030 have a high degree of angular uniformity and can exit the reflector substantially parallel to each other. Thus, the edge rays are collimated by the CPC. However, the spatial uniformity of the output light is poor. Undesirably, light emitted from the reflector 2010 can form hot spots in the ring shape.

[0089] Referring to Figures 11-12, a lens (e.g., a Fourier transform lens) may be used to convert the angle-uniform optical output of the reflector into a spatially uniform optical output. Figure 11 illustrates an embodiment of an optical system 2100 having a reflector 2110 and a lens 2120. The reflector 2110 has an optical input aperture 2102 and an optical output aperture 2104, and is accompanied by internal sidewalls 2112a, 2112b extending from the optical input aperture 2102 to the optical output aperture 2104. The internal sidewalls 2112a, 2112b are curved to provide an angle-uniform optical output to the lens 2120. In some embodiments, the sidewalls 2112a, 2112b have a CPC profile; that is, the curvature of the internal sidewalls 2112a, 2112b follows that of a composite parabolic condenser. It should be understood that in some embodiments, the internal sidewalls 2112a, 2112b may follow an elliptical, hyperbolic, or biconical contour. In some other embodiments, the internal sidewalls 2112a, 2112b may be substantially linear, which has been found to provide a sufficiently angularly uniform light output for the lens 21020 to output very spatially uniform light. Although the sidewalls 2112a, 2112b are shown separately in the illustrated cross-section, it should be understood that in an actual three-dimensional reflector, 2112a and 2112b are simply opposing sides of a continuous surface. Preferably, the sidewalls 2112a, 2112b are specular reflectors. In some embodiments, the sidewalls 2112a, 2112b may be formed from and / or lined with a reflective material.

[0090] Figure 12 illustrates an embodiment of an optical system 2100 having an optical emitter 2140 positioned to emit light into a reflector 2110. In some embodiments, the optical emitter 2140 is located outside the optical input aperture. In some other embodiments, the optical emitter 2140 is located inside the internal volume of the reflector 2110. In some embodiments, the optical emitter 2140 has a Lambertian emission pattern. The optical emitter 2140 may be, for example, a light-emitting diode (LED), an incandescent bulb, a fluorescent bulb, or other device that converts electrical energy into light.

[0091] Continuing to refer to Figures 11 and 12, the lens 2120 is close to the optical output aperture 2104. In some embodiments, the lens 2120 is located in front of or directly in front of the optical output aperture 2104. In some other embodiments, the lens 2120 may be located inside the reflector 2110. Preferably, the distance from the lens 2120 to the optical emitter 2140 is substantially equal to the focal length of the lens. In addition, the distance from the lens to the optical modulator (not shown) is also preferably substantially equal to the focal length of the lens.

[0092] It should be understood that the illustration of lens 2120 is schematic. It should also be understood that lens 2120 is an optically transparent structure configured to convert the angle-uniform optical output of reflector 2110 into a spatially uniform optical output. For example, as shown, light rays 2130 emitted by optical emitter 2140 are reflected from sidewalls 2112a, 2112b so that they propagate in substantially the same direction. Lens 2120 then converts this angle-uniform output into spatially uniform light 2130 that propagates away from lens 2120. In some embodiments, the lens may be a single lens. In some other embodiments, lens 2120 may be a composite lens, such as a double lens or lens system. Preferably, lens 2120 extends across substantially the entire area of ​​the optical output aperture 2104.

[0093] Figure 13 illustrates an embodiment of light output from the optical system 2100 of Figures 11-12. The light propagates away from the optical emitter 2140 into the lens 2120, and then from the lens 2120 to the optical modulator 209b. The lens 2120 and the optical modulator 209b are schematically represented as lines in this figure. As described herein, the distance between the optical emitter 2140 and the lens 2120 may be equal to the focal length of the lens, and the distance between the lens 2120 and the optical modulator 209b may also be equal to the focal length of the lens.

[0094] In some embodiments, the reflector 2110 has an optical input aperture and an optical output aperture of the same shape, for example, circular. In some other embodiments, the shapes of the optical input aperture and the optical output aperture are different. Figures 14A-14F illustrate embodiments of the reflector having optical input apertures and optical output apertures with different shapes. The ability to vary the shapes of the optical input aperture and the optical output aperture can provide the advantage of efficiently matching optical emitters and optical modulators having different shapes or aspect ratios.

[0095] Figures 14A-14C illustrate a reflector 2110 with a stepped elliptical shape. Figure 14A is a perspective view with a light output aperture 2104 facing the viewer. Figure 14B is a side view looking directly at the plane 14B of Figure 14A. Figure 14C is another side view, here looking directly at the plane 14C of Figure 14A. Plane 14B is perpendicular to plane 14C. As shown, in some embodiments, the light input aperture 2102 of the reflector 2110 has a circular shape, which expands stepped at different rates so that the light output aperture 2104 has an elliptical shape, as seen along planes 14A and 14B. For example, side walls 2112a and 2112b expand outward at a greater rate than side walls 2112c and 2112d. In some embodiments, a notch 2114 may be present in the light input aperture 2102 and extend into the side wall 2112c. The notch 2114 may allow a connector (e.g., a wire bond) for an optical emitter (e.g., optical emitter 2140, Figure 12) to be accommodated.

[0096] Figures 14D-14F illustrate a reflector 2110 with a rectangular light input aperture 2102. Figure 14D is a perspective view with a light output aperture 2104 facing the viewer. Figure 14E is a side view looking directly at the plane 14E of Figure 14D. Figure 14F is another side view, here looking directly at the plane 14F of Figure 14D. Plane 14E is perpendicular to plane 14F. As illustrated, in some embodiments, the light input aperture 2102 of the reflector 2110 has a rectangular shape (e.g., square shape), which expands in stages so that the light output aperture 2104 has a rectangular shape with different lengths and widths. It should be understood that a square light input aperture 2102 may be beneficial for meshing with square light emitters such as many LEDs. On the other hand, in applications where the reflector 2110 is used to supply light to the optical modulator 209b (Figure 6), the optical modulator 209b may be configured to produce an image in a standard aspect ratio, where one dimension is larger than the other crossing dimension (for example, the aspect ratios may be 4:3, 16:9, etc.). As shown in Figure 14D, the optical output aperture 2104 may have two straight sides 2104a, 2104b joined by two curved sides 2104c, 2104d.

[0097] Referring to Figures 14A-14F, planes 14A, 14B, 14E, and 14F are central planes that substantially divide the various illustrated embodiments of the reflector 2110 (at least with reference to the optical output aperture 2104). It should be understood that the distance from the optical output aperture 2104 to the optical input aperture 2102 can be considered to be the height of the reflector 2110, and that planes 14A, 14B, 14E, and 14F can each be considered to have axes extending along the height axis of the reflector 2110. In addition, the pairs of central planes 14A and 14B, and 14E and 14F are orthogonal to each other. Preferably, as seen in the central planes 14A, 14B, 14E, and 14F, the internal sidewalls 2112a, 2112b, 2112c, and 2112d each follow the CPC profile and have composite parabolic concentrators of a certain curvature.

[0098] An optical system comprising a reflector and a lens provides highly spatially uniform light output. Figures 15A and 15B illustrate embodiments of uniformity maps for the light output of the reflector shown in Figures 14A-14C and 14D-14F, respectively. In these maps, different colors represent different light intensities. Advantageously, as shown, the colors and intensities are highly uniform, demonstrating high spatial uniformity.

[0099] The optical output also exhibits good angular uniformity. Figure 16 illustrates an example of a map showing the intensity of the optical output in angular space for the reflector of Figures 14A–14C in combination with the lens, according to an embodiment of this specification. V corresponds to the angular spread of the optical output along the principal (longer) axis of the optical output aperture 2104 (Figure 14A), H corresponds to the angular spread of the optical output along the secondary (short) axis of the optical output aperture 2104, and the diagonal corresponds to the angular spread of the optical output along the diagonal of the optical output aperture. It is noteworthy that the cutoffs for V, H, and each diagonal are sharp, indicating that the angles at which light exits the lens are similar, with minimal stray light outside those angles.

[0100] In some embodiments, the reflector and lens system may form part of an array of reflectors and lenses. Since reflectors can simply be formed within a well-formed volume, the array of reflectors may be formed within a single body of material. Figures 17A–17B illustrate perspective views of embodiments of the array of reflectors in Figures 14A–14C and 14D–14F, respectively. Figure 17A shows a reflector having an elliptical light output aperture, as discussed with respect to Figures 14D–14F, and Figure 17B shows a reflector having an elongated output aperture with straight and curved edges. In both Figures 17A and 17B, the multiple reflectors 2110 may be formed within a body of material 2200, for example, within a plate of material. Although shown similarly for the sake of illustration, it should be understood that the size and / or shape of the reflectors within the body 2200 may vary in some embodiments.

[0101] It should be understood that the body 2200 may be formed from a variety of materials having sufficient mechanical integrity to maintain the desired shape of the reflector 2110. Examples of preferred materials include metal, plastic, and glass. As discussed herein, the body 2200 may be a plate. In some embodiments, the body 2200 is a continuous, one-piece component of the material. In some other embodiments, the body 2200 may be formed by joining together two or more components of the material.

[0102] The reflector 2110 may be formed within the body 2200 by various methods. For example, the reflector 2110 may be formed by machining the body 2200, or by removing material in a different way and engraving the reflector 2110. In some other embodiments, the reflector 2110 may be formed as the body 2200 is formed. For example, the reflector 2110 may be molded into the body 2200 as the body 2200 is molded into its desired shape. In some other embodiments, the reflector 2110 may be formed after the body 2200 has been formed by rearranging the material. For example, the reflector 2110 may be formed by imprinting.

[0103] Once the contour of the reflector 2110 is formed, the reflector volume may undergo further processing to form an inner surface having a desired reflectivity. In some embodiments, the surface of the body 2200 itself may be reflective, for example, the body may be formed from a reflective metal. In such cases, the further processing may simply involve smoothing the inner surface of the reflector 2110 to increase its reflectivity. In some other embodiments, the inner surface of the reflector 2110 may be lined with a reflective coating.

[0104] It should be understood that the shaping of the reflector 2110 as described above allows the light output of the reflector to be shaped in angular space, providing an asymmetric angular distribution. Advantageously, the reflector shape may be used to provide a light output that conforms to a desired display aspect ratio, as described herein. In some other embodiments, the desired aspect ratio may be achieved using a mask placed in front of the lens.

[0105] Figure 18 illustrates a perspective view of an embodiment of an optical system having an array of optical emitters 2140, reflectors 2110, and lenses 2120, and a mask 2400. In some embodiments, the optical emitters 2140 are mounted on a support substrate 2300, for example, a printed circuit board. The spatial layout of the optical emitters 2140 and reflectors 2110 is preferably matched so that each optical emitter 2140 is perpendicularly aligned with its individual corresponding reflector 2110. In some embodiments, the array of optical emitters 2140, reflectors 2110, and lenses 2120, and optionally the mask 2400, may form an optical module 540 (Figure 6).

[0106] In some embodiments, all optical emitters 2140 may be similar. In some other embodiments, at least some of the optical emitters 2140 may be different, for example, some optical emitters may emit light at different wavelengths or wavelength ranges than the others. For example, the optical emitters 2140 may form a group of optical emitters, for example, three groups of optical emitters, each group emitting light at wavelengths corresponding to different colors (e.g., red, green, and blue). In some embodiments, there may be more than three groups of optical emitters (to emit light at more than three different wavelength ranges). Different groups of optical emitters may be used to provide different primary color light for a display system such as a display system 250 (Figure 6). For example, the optical emitters in each group may be used to emit rays 770, 780, and 790 (Figures 9A-9B).

[0107] In some embodiments, an optical emitter, a reflector, and a lens are used to supply light to a stack of waveguides 660 (Figures 9A-9C). In such embodiments, in addition to matching the spatial layout of the optical emitter 2140 with the spatial layout of the reflector 2110, the optical emitter 2140 and the reflector 2110 are also preferably arranged to match the spatial layout of internally coupled optical elements (e.g., internally coupled optical elements 700, 710, 720) in the stack of waveguides 660. Preferably, the spatial layout of the optical emitter 2140 and the reflector 2110 matches the spatial layout of the internally coupled optical elements 700, 710, 720 such that the spatial arrangement of the reflector 2110 corresponds one-to-one with the spatial arrangement of the internally coupled optical elements 700, 710, 720, as seen in the plan view. By using such an arrangement, light from a particular optical emitter can be reliably directed into one of the associated waveguides 670, 680, or 690, rather than being directed into the others of waveguides 670, 680, or 690.

[0108] Continuing to refer to Figure 18, in the orientation shown for the optical system 2100, the optical input aperture of the reflector is at the bottom of the body 2200, and the optical output aperture is at the top of the body 2200. Preferably, the lower surface of the body 2200 is contoured to lie flat on the upper surface of the substrate 2300 so that light does not significantly propagate from the optical emitter into reflectors 2110 other than the reflector matching the optical emitter. Advantageously, both the lower surface of the body 2200 and the upper surface of the substrate 2300 may be flat, which can facilitate a tight fit at the interface between the body 220 and the substrate 2300 and prevent unwanted stray light from reaching the individual reflectors 2110.

[0109] Lens 2120 is provided at the light output aperture of the reflector 2110. As shown in the figure, each reflector 2110 has an individual associated lens 2120. In some other embodiments, some or all of the lenses may be formed within a single sheet of material. In such embodiments, the sheet of material is preferably thin, for example, thin enough to minimize light leakage between reflectors while maintaining sufficient structural integrity and holding the lenses together.

[0110] Continuing to refer to Figure 18, the mask 2400 is provided in front of the lens 2120. The mask 2400 has an opening 2402, for example, a cutout, in a desired shape for light output. Thus, the mask 2400 may be used for spatial light shaping. The opening 2402 preferably has a smaller area than the light output opening of the reflector. In some embodiments, the mask surface facing into the reflector (e.g., the bottom surface of the mask 2400) is reflective, which can increase the efficiency and brightness of the optical module comprising the light emitter 2140, the reflector 2110, and the lens 2120. In some other embodiments, the bottom surface is absorptive, which can provide greater control over the path of light passing from the reflector 2110 through the opening 2402 by preventing random reflection between the bottom surface of the mask and the reflector 2110.

[0111] In addition to defining the contour of the reflector 2110, the body 2200 may include other structures for other purposes. Figure 19 illustrates a perspective view of an embodiment of the body 2200 having an array of reflectors 2110 and recesses 2210 for optical emitter structures such as wiring. The recesses 2210 may accommodate a portion of the optical emitter 2140 (Figure 18) or a structure connected to the optical emitter 2140, and are shaped and have such depth so that the body 2200 can tightly fit to the substrate 2300 without light leakage. Similar to the reflector 2110, the recesses 2210 may be formed by various methods, including machining, molding, and imprinting.

[0112] In some embodiments, the body 2200 may have a uniform thickness. In some other embodiments, the thickness of the body 2200 may vary. Figures 20A–20B illustrate perspective views of embodiments of the body 2200 of the material having reflectors at different heights. Since the reflectors extend entirely through the body 2200, the different heights for the reflectors may be achieved by setting the thickness of the body 2200 to different heights. As an embodiment, Figures 20A–20B illustrate three heights or levels 2200a, 2200b, and 2200c. It should be understood that fewer or greater levels may be provided as desired, and the levels may be arranged differently from those shown in some embodiments.

[0113] Different heights for the reflector 2110 may offer advantages for applications where different groups of light emitters 2140 (Figure 18) emit light of different wavelengths. Light of different wavelengths may be focused to different distances from the corresponding light emitters 2140. As a result, with different heights selected based on the distance at which the light is best focused, the reflector 2110 may be expected to provide improved image quality when the light emitters 2140, reflector 2110, and lens 2120 are used in a display system. In some embodiments, where the lens 2120 is positioned at one focal distance from the associated light emitter 2140, the distance corresponding to one focal distance may vary with respect to the wavelength of the emitted light and a portion of the thickness of the body 2200, and the light emitter 2140 and associated reflector 2110 and lens 2120 may be adapted to allow the placement of the lens 2120 at a suitable one focal distance from the light emitter 2140.

[0114] In some other embodiments, all reflectors 2110 may have the same height, and the lenses 2120 for different groups of light emitters 2140 may be different. For example, the lenses 2120 for different groups of light emitters 2140 may have different focal lengths and be configured to account for differences caused by light of different wavelengths.

[0115] Referring here to Figures 21A-21E, various diagrams of embodiments of the reflector 2110 are illustrated. It should be understood that the reflector 2110 may take on various shapes that follow the CPC profile. In some embodiments, the reflector 2110 may be formed by multiple edges or facets, each having a CPC profile as seen in the side view. That is, in some embodiments, all inner edges of the reflector 2110 may have a CPC profile when each edge is seen in the side view. Figure 21A shows the reflector 2110 as seen looking down at the reflector from the optical input aperture end. Figures 21B and 21C show the reflector 2110 as seen from the opposite side. Figure 21D shows the reflector 2110 as seen from an edge perpendicular to the edges seen in Figures B and C. Figure 21E shows a perspective view of the reflector 2110 as seen from the optical output end of the reflector. Both side walls 2112a and 2112b may have a CPC profile, and both side walls 2112c and 2112d may also have a CPC profile. In addition, all other sides may have a CPC profile, as seen in the side view. Furthermore, in some embodiments, as can be seen from the figures 21A and 21E, each side of the reflector 2110 is linear or flat when viewed in a cross-sectional view obtained along a plane lateral to the height axis of the reflector 2110 (extending from the input end 2102 to the output end 2104).

[0116] In some embodiments, two opposing sides, for example, sides 2112c and 2112d or sides 2112a and 2112b, have the same CPC profile, but their profiles differ from the CPC profiles of all other sides. In addition, all other sides may have the same CPC profile. Thus, in some embodiments, the curvature of all inner sides of the reflector 2110 may be the same, except for that of a pair of opposing inner sides. In some other embodiments, as described herein, the inner sides of the reflector 2110 may follow other contours, including elliptical, hyperbolic, or biconical shapes, or the reflector 2110 may be substantially linear from the input end 2102 to the output end 2104.

[0117] Preferably, the total number of sides is an even number, such as 4, 6, 8, 10, 12, etc. In some embodiments, the total number of sides may be 8 or more, which has been found to provide a very spatially uniform optical output.

[0118] It should be understood that the optical input aperture 2102 may be sized to accommodate the lower layer optical emitter. In some embodiments, the optical emitter may have a maximum width of about 500 μm or more, 600 μm or more, 700 μm or more, or 800 μm or more. In some embodiments, the optical input aperture 2102 may have a maximum width of 500 μm or more, 600 μm or more, 700 μm or more, 800 μm or more, 900 μm or more, or 1 mm or more. In some embodiments, the optical input aperture 2102 has a width of less than 2 mm, less than 1.5 mm, or less than 1 mm.

[0119] Figures 22A-22B illustrate additional perspective views of the reflector 2110 in Figure 21. Figures 22C-22D illustrate yet another additional perspective views of the reflector 2110 as seen from the light output aperture side and the light input aperture side, respectively.

[0120] Figures 23A and 23B illustrate examples of uniformity maps for optical output of reflectors with rounded profiles (as seen in the cross-section obtained along a plane perpendicular to the height axis of the reflector) and reflectors with acute angles at the intersections of substantially linear internal sidewalls (as seen in the cross-section obtained along a plane perpendicular to the height axis of the reflector), respectively. Undesirably, as shown in Figure 23A, a reflector with a rounded profile provides an optical output with a low-intensity area in the center of the map. While this low-intensity area is undesirable in itself, it should be understood that the center of the map may also be the center of the viewer's field of vision, and the viewer may be particularly sensitive to non-uniformity within this area. Advantageously, as shown in Figure 23B, an eight-sided reflector with acute angles and CPC profiles on each side, as described above with respect to Figures 21-22D, provides very uniform optical output.

[0121] Various exemplary embodiments of the present invention are described herein. These embodiments are provided in a non-limiting sense to illustrate broader applicable aspects of the invention. Various modifications may be made to the described invention, and equivalents may be substituted without departing from the spirit and scope of the invention.

[0122] For example, it is advantageous to use it with an AR display that provides images across multiple depth planes, but the augmented reality content disclosed herein may also be displayed by a system that provides images on a single depth plane.

[0123] In addition, while advantageously applied as a light source for display systems, the reflector and lens systems disclosed herein may be used in other applications where highly spatially uniform light is desired. Furthermore, the simple mechanical structure of the reflector and lens facilitates its use in arrays of reflectors and lenses, but the reflector and system may also be used in optical systems with a single reflector and associated lens.

[0124] Furthermore, the reflector 2110 (Figure 14C) may have a notch 2114 for accommodating a connector such as a wire bond for the optical emitter, but it should be understood that in some other embodiments, the notch 2114 may be omitted. For example, the side wall 2112c may continue at the same level as the other side walls of the reflector 2110. In such embodiments, an optical emitter without a protruding wire bond may be used, and the side walls of the reflector 2110 may extend to contact a substrate such as a printed circuit board supporting the optical emitter. An embodiment of an optical emitter without a protruding wire bond is a flip-chip LED. It has been found that a wire bond extending across the optical emitter can produce shadows that produce visible artifacts in the image formed using the optical emitter. Advantageously, eliminating the wire bond and extending the reflector side walls to the optical emitter substrate can eliminate such artifacts and improve image quality.

[0125] In addition, numerous modifications may be made to adapt specific situations, materials, compositions, processes, actions or steps of a process to the object, spirit, or scope of the present invention. Furthermore, as will be understood by those skilled in the art, each of the individual modifications described and illustrated herein has discrete components and features that can be readily separated from or combined with features of any of several other embodiments without departing from the scope or spirit of the present invention. All such modifications are intended to be within the scope of the claims associated with this disclosure.

[0126] The present invention includes methods that may be performed using the device. The methods may include the act of providing such a suitable device. Such provision may be performed by a user. In other words, the act of “providing” is merely requiring the user to acquire, access, approach, position, configure, activate, power on, or otherwise operate in order to provide the necessary device in the method. The methods described herein may be performed in any logically possible order of the described events, as well as in the order in which the events are described.

[0127] Exemplary aspects of the present invention, along with details relating to material selection and manufacturing, are described above. Other details of the present invention are understood in connection with the above-referenced patents and publications and, generally, can be grasped or understood by those skilled in the art. The same may apply to the method-based aspects of the present invention in terms of additional actions that are generally or logically adopted.

[0128] In addition, although the present invention has been described with reference to several embodiments that optionally incorporate various features, the present invention is not limited to those described or indicated to be considered with respect to each modification of the present invention. Various modifications may be made to the described invention, and equivalents may be substituted (whether described herein or not for the sake of some brevity) without departing from the spirit and scope of the invention. In addition, if a range of values ​​is provided, it is understood that all intermediate values ​​between the upper and lower limits of that range, and any other specified or intermediate values ​​within that specified range, are encompassed within the present invention.

[0129] Furthermore, it should be considered that any optional feature of a variation of the invention described herein may be described and claimed independently or in combination with any one or more features of those described herein. References to singular items include the possibility of multiple identical items existing. More specifically, as used herein and in the claims associated therewith, the singular forms “a, an,” “said,” and “the” include multiple referents unless otherwise specifically stated. In other words, the use of articles allows for “at least one” of the subject items in the above description and in the claims associated with this disclosure. Furthermore, it should be noted that such claims may be drafted to exclude any optional elements. Therefore, this statement is intended to function as an antecedent for the use of such exclusive terms, or “negative” restrictions, such as “only,” “only,” and “equivalents,” relating to the description of claim elements.

[0130] Without using such exclusive terms, the term “equipped with” in the claims associated with this disclosure shall allow for the inclusion of any additional elements, whether a given number of elements are enumerated in such claims or whether the addition of features can be considered to transform the nature of the elements described in such claims. Unless otherwise specifically defined herein, all technical and scientific terms used herein are given the broadest possible generally understood meaning while maintaining the validity of the claims.

[0131] The scope of the present invention is not limited to the provided examples and / or specification, but rather is limited only to the claims associated with this disclosure.

Claims

1. A display system, wherein the display system is A reflector, wherein the reflector is Input terminal and Output terminal and A plurality of side walls extending between the input end and the output end, wherein two opposing side walls of the reflector have a first curved cross-sectional profile, and the remaining side wall has a second curved cross-sectional profile different from the first cross-sectional profile, the first curved cross-sectional profile and the second curved cross-sectional profile are defined by the cross-section from the input end to the output end, and the number of the plurality of side walls is even. A reflector comprising, A lens, wherein the lens is located at a distance equal to the focal length of the lens from the input end of the reflector, A spatial light modulator configured to receive light from the lens and to form an image by modulating the light, A mask located between the reflector and the spatial light modulator, wherein the mask has an opening smaller than the output end, and the mask is configured to limit the angular spread of light incident on the spatial light modulator. A display system equipped with the following features.

2. The display system according to claim 1, wherein the mask is located between the lens and the spatial light modulator.

3. The display system according to claim 1, wherein the mask has a mask surface facing the reflector, and the mask surface is absorbent.

4. The display system according to claim 1, wherein the opening of the mask is aligned to the center with respect to the optical axis of the reflector.

5. The display system according to claim 1, wherein the opening of the mask has a polygonal shape corresponding to the plurality of side walls of the reflector.

6. The display system according to claim 1, wherein the mask is positioned to block peripheral light rays emitted from the output end of the reflector.

7. The display system according to claim 1, wherein the mask comprises an opaque plate.

8. The display system according to claim 1, wherein the mask is positioned immediately adjacent to the output end of the reflector.

9. The display system according to claim 1, wherein the mask is spaced apart from the spatial light modulator by a distance selected to control the principal ray angle of the light incident on the spatial light modulator.

10. The display system according to claim 1, wherein the mask opening is sized to allow only light within a predetermined angular range to pass through.

11. The display system according to claim 1, wherein the mask is configured to reduce illumination non-uniformity across the spatial light modulator.

12. The display system according to claim 1, wherein the mask comprises a light-absorbing material selected to minimize reflection.

13. The display system according to claim 1, wherein the mask opening has an aspect ratio selected to match the active area of ​​the spatial light modulator.

14. The display system according to claim 1, wherein the plurality of side walls are arranged to define a tapered reflector geometry between the input end and the output end.

15. The display system according to claim 1, wherein the reflector is configured to generate a substantially uniform illumination distribution at the output end.

16. The display system according to claim 1, wherein the lens is positioned such that the input end of the reflector is substantially located at the focal point of the lens.

17. The display system according to claim 1, wherein the lens comprises at least one of a refractive lens, a distributed refractive index lens, and an aspherical lens.

18. The display system according to claim 1, wherein the spatial light modulator is configured to modulate the light in a time-series image frame.

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