Display system with variable beam expansion for multiple lasers

Abstract

To reduce clipping and loss of brightness of a projected image.SOLUTION: There is provided a laser projection system (200), where light output by an optical engine is directed to a first scan mirror (206) as two angularly separated laser light beams (1002 and 1102). The angularly separated laser light beams typically have different angles of incidence (1010 and 1110) on a second scan mirror (208) of an optical scanner. Respectively different levels of magnification are applied to a beam diameter of each of the angularly separated laser light beams in a first dimension, such that the angularly separated laser light beams have respectively different beam diameters (1012 and 1112) upon incidence at the second scan mirror. The different beam diameters of the angularly separated laser light beams result in regions of incidence of each of the angularly separated laser light beams on the second scan mirror being equal or substantially similar.SELECTED DRAWING: Figure 1

Description

[Background technology]

[0001] background Some display systems use projectors, which are optical devices that project or illuminate a pattern of light onto another object (e.g., onto the surface of another object, such as onto a projection screen) to display an image or video on or through the other object. In projectors that use lasers as light sources (i.e., "laser projectors"), each beam of laser light generated by the laser projector is temporally modulated to provide a pattern of laser light, and controllable mirrors, such as digital micromirrors, are typically used to spatially distribute the modulated pattern of laser light over a two-dimensional area of ​​the other object. The spatial distribution of the modulated pattern of laser light generates an image of the other object. Summary of the Invention

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

[0003] [Figure 1] FIG. 1 illustrates a display system having an integrated laser projection system, according to some embodiments. [Figure 2] FIG. 1 illustrates a laser projection system having an optical scanner including an optical repeater disposed between two scanning mirrors, according to some embodiments. [Figure 3] FIG. 1 illustrates a waveguide having an input coupler, an output coupler, and an exit pupil expander in accordance with some embodiments. [Figure 4] FIG. 1 illustrates a laser projection system including a molded reflective relay disposed between two scanning mirrors, according to some embodiments. [Figure 5]1 illustrates a laser projection system including a molded reflective repeater disposed between two scanning mirrors, illustrating the light path through the molded reflective repeater, according to some embodiments. [Figure 6] FIG. 1 illustrates a partial see-through view of a wearable head-up display (WHUD) including a laser projection system, according to some embodiments. [Figure 7] FIG. 2 illustrates a partially transparent front isometric view of a laser projection system disposed within a WHUD, according to some embodiments. [Figure 8] FIG. 2 illustrates a partially transparent rear isometric view of a laser projection system disposed within a WHUD, according to some embodiments. [Figure 9] FIG. 1 illustrates a top view of a portion of a laser projection system in which a pair of angularly separated lasers are routed through an optical scanner and incident on an input coupler, according to some embodiments. [Figure 10] FIG. 2 illustrates a top view of a portion of a laser projection system in which a laser light beam is incident on a reflective surface of a second scanning mirror, according to some embodiments. [Figure 11] A diagram showing a top view of a portion of a laser projection system in which a laser light beam is incident on a reflective surface of a second scanning mirror at an angle that can result in a portion of the laser light beam missing the reflective surface depending on the beam diameter of the laser light beam, in some embodiments. [Figure 12] FIG. 1 illustrates a top view of an optical scanner of a laser projection system in which a first amount of beam expansion is applied to a first laser light beam by a first reflective surface of an optical repeater, according to some embodiments. [Figure 13] FIG. 10 illustrates a top view of an optical scanner of a laser projection system in which a second amount of beam expansion is applied to the second laser light beam by a second reflective surface of the optical repeater, according to some embodiments. [Figure 14]A figure showing a top view of an optical scanner of a laser projection system including a first reflective surface of the example of Figure 12 and a second reflective surface of the example of Figure 13, each providing different levels of magnification to angularly separated laser light beams, in accordance with some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0004] Detailed Description 1-14 illustrate embodiments for compactly arranging a near-eye display system (e.g., a wearable head-up display (WHUD)) or another display system having multiple angularly separated laser inputs, each of which has different amounts of beam expansion applied by different reflective surfaces of an optical repeater. Using the techniques described herein, two or more laser inputs (sometimes referred to herein as "laser light beams") of such a display system are angularly separated with respect to one another, such that these two or more laser light beams are neither parallel nor perpendicular to one another, but instead propagate along tilted (i.e., "angularly offset," "angularly separated") optical paths. Due to the angular separation of two or more laser light beams, the angles of incidence of each of such laser light beams on one or more scanning mirrors of the system's optical scanner are typically different, resulting in different sized incidence areas of the laser light beams on such scanning mirrors for laser light beams having the same or similar beam diameters, which can affect performance and user experience in a WHUD. To compensate for differences in the angles of incidence and corresponding areas of the incidence regions of such angularly separated light beams, different levels of beam expansion (i.e., magnification) are applied to each of the angularly separated laser light beams, so that in some embodiments, the areas of the incidence regions of each of the angularly separated laser light beams on a given scanning mirror of the optical scanner are the same or approximately the same.

[0005] To further illustrate, in some examples, laser light beams are provided on the scanning mirror having incident areas significantly larger or smaller than the reflective surface of the scanning mirror. For example, portions of the angularly separated laser light beams miss the reflective surface of the scanning mirror, resulting in a loss of brightness in the image projected by the near-eye display system. Image brightness can be maintained at a relatively high level by reducing the level of magnification applied to any of the angularly separated laser light beams that would otherwise have an incident area larger than the reflective surface of the scanning mirror. As another example, providing laser light beams with an incident area smaller than the reflective surface of the scanning mirror results in an underutilization of the reflective surface of the scanning mirror and a corresponding reduction in the optical resolution of the near-eye display. This underutilization of the reflective surface is mitigated by increasing the level of magnification applied to any of the angularly separated laser light beams that would otherwise have an incident area smaller than the reflective surface of the scanning mirror.

[0006] In some embodiments of the technology disclosed herein, a display system includes a laser projection system including an optical engine having at least two modulatable laser light sources, two scanning mirrors, an optical repeater, and a waveguide. In operation, the at least two modulatable laser light sources provide laser light (output as two or more angularly separated laser light beams), and the two scanning mirrors sequentially receive the laser light, each scanning the laser light across a respective direction (e.g., the first scanning mirror scans the light along a first dimension and the second scanning mirror scans the light along a second dimension, where the second dimension may be substantially perpendicular to the first dimension). The waveguide includes an input coupler at which it receives the scanned laser light from the second scanning mirror. The input coupler redirects the received light through the waveguide, in some examples via an intervening exit pupil expander (EPE), towards an output coupler of the waveguide, where the light exits the waveguide (e.g., towards a user's eye). so that it is projected onto

[0007] In some embodiments of such a display system, two angularly separated laser light beams are output (e.g., via an optical engine and a beam combiner) to an optical scanner including first and second scanning mirrors and an optical repeater. The display system is configured such that a first of the two angularly separated laser light beams is incident on the first scanning mirror, which scans the first laser light beam along a first scanning dimension onto a first reflective surface of the optical repeater. A second of the two angularly separated laser light beams is also incident on the first scanning mirror, which scans the second laser light beam along the first scanning dimension onto a second reflective surface of the optical repeater. The first reflective surface directs the first laser light beam toward a third reflective surface of the optical repeater. The second reflective surface directs the second laser light beam toward a fourth reflective surface of the optical repeater. The third reflective surface directs the first laser light beam toward the second scanning mirror, which scans the first laser light beam across a first region of the waveguide input coupler along a second scanning dimension at least substantially perpendicular to the first scanning dimension. The fourth reflective surface directs the second laser light beam toward the second scanning mirror, which scans the second laser light beam across a second region of the waveguide input coupler along the second scanning dimension. In some embodiments, the first region of the input coupler overlaps the second region of the input coupler.

[0008] In some embodiments, the first and second reflective surfaces of the optical repeater are non-overlapping reflective surfaces of molded optical repeaters. In some embodiments, the third and fourth reflective surfaces of the optical repeater are non-overlapping surfaces of molded optical repeaters. In some embodiments, the first reflective surface expands the beam diameter of the first laser light beam having a first magnitude along a first "non-scanning" dimension that is perpendicular or substantially perpendicular to the scanning dimension and the direction of propagation of the first laser light beam (sometimes referred to herein as performing beam expansion or magnification). In some embodiments, the second reflective surface expands the beam diameter of the second laser light beam having a second magnitude along a second non-scanning dimension that is perpendicular or substantially perpendicular to the scanning dimension and the direction of propagation of the second laser light beam. In some embodiments, the first magnitude is different from the second magnitude. In some embodiments, the first reflective surface has a different optical prescription than the second optical prescription of the second reflective surface, resulting in different amounts of beam expansion being applied to the first laser light beam by the first reflective surface and to the second laser light beam by the second reflective surface along the first and second non-scanning dimensions, respectively.

[0009] Generally, as the angle of incidence of a given laser light beam on a surface (such as that of a scanning mirror) deviates from the normal to that surface, the area of ​​the surface region on which the laser light beam is incident increases. The surface region on which the laser light beam is incident is sometimes referred to herein as the “incident region.” In an example laser projection system, if the incident region of a given laser light beam and a given scanning mirror is larger than the reflective surface of the scanning mirror, the portion of the laser light beam that does not impinge on the reflective surface will not be reflected by the scanning mirror (a scenario sometimes referred to as “clipping” or “aperture clipping”), resulting in a loss of brightness in the image displayed using the laser projection system. In particular, in embodiments of the laser projection system of the present disclosure that utilize two or more angularly separated laser light beams as inputs, each laser light beam will typically have a different angle of incidence on the second scanning mirror, resulting in different sized incident regions on the second scanning mirror. Assuming that each of the laser light beams input to the laser projection system initially have the same or substantially the same beam diameter and have different angles of incidence relative to the second scanning mirror, the incidence areas of the laser light beams relative to the second scanning mirror will be such that beams of the same level (i.e., magnitude) are formed along the respective non-scanning dimensions of each of the laser light beams via the reflective surface of the optical repeater. If beam expansion is applied, the laser light beams will have different sizes, resulting in non-idealities. For example, if at least one of the incidence areas of the laser light beams exceeds the size of the reflective surface of the second scanning mirror, undesirable clipping and loss of brightness of the projected image will result. This loss of brightness can be mitigated by instead applying a reduced level of expansion to any laser light beams having incidence areas with respective areas that exceed (e.g., significantly exceed) that of the reflective surface of the second scanning mirror. As another example, if at least one of the laser light beams has an incidence area on the second scanning mirror that is smaller (e.g., significantly smaller) than the reflective surface of the second scanning mirror, the optical resolution of the projected image will be undesirably reduced. This reduction in optical resolution can be mitigated by instead applying a greater level of expansion to any laser light beams having incidence areas with respective areas that are smaller (e.g., significantly smaller) than the reflective surface of the second scanning mirror.

[0010] As identified above, by applying different levels of beam expansion to the angularly separated laser light beams of such a laser projection system along respective non-scanning dimensions (e.g., via different reflective surfaces having different optical prescriptions), the size of the respective incidence area of ​​each of the angularly separated laser light beams on the second scanning mirror can be independently selected. For example, by applying different levels of beam expansion to the first and second angularly separated laser light beams along respective non-scanning dimensions (where the first and second angularly separated laser light beams have the same initial beam diameter and different angles of incidence on the second scanning mirror), the first incidence area of ​​the first laser light beam can be set to be equal to or approximately equal to the second incidence area of ​​the second laser light beam, and in some embodiments, equal to or approximately equal to the size of the reflective surface of the second scanning mirror.

[0011] According to embodiments of the present disclosure, a laser projection system is provided that includes an optical relay having reflective surfaces with different optical prescriptions, such that different levels of beam expansion are applied to angularly separated laser light beams incident on the respective reflective surfaces. In some embodiments, different levels of beam expansion are applied along respective non-scanning dimensions of the angularly separated laser light beams, such that the angularly separated laser light beams have similar or identically sized respective incident areas on the second scanning mirror relative to each other, relative to the reflective surface of the second scanning mirror, or both.

[0012] It should be noted that while some embodiments of the present disclosure are described and illustrated with reference to a particular exemplary near-eye display system in the form of a wearable head-up display (WHUD), it is understood that the apparatus and techniques of the present disclosure are not limited to this particular example, but instead may be implemented in any of a wide variety of display systems using the guidelines provided herein.

[0013] 1 illustrates an exemplary display system 100 using scanning-based optics according to some embodiments, having a support structure 102 including an arm 104 that houses a laser projection system configured to project images toward a user's eye such that the user perceives the projected image as being displayed within a field of view (FOV) area 106 of the display on one or both of lens elements 108, 110. In the illustrated embodiment, display system 100 is a near-eye display system in the form of a WHUD, in which support structure 102 is configured to be worn on the user's head and has the general shape and appearance (i.e., form factor) of an eyeglass (e.g., sunglasses) frame. Support structure 102 contains or may include various components to facilitate the projection of such images toward the user's eye, such as a laser projector, optical scanner, and waveguide. In some embodiments, the support structure 102 further includes various sensors, such as one or more front-facing cameras, rear-facing cameras, other light sensors, motion sensors, accelerometers, etc. The support structure 102 may further include one or more radio frequency (RF) interfaces or other wireless interfaces, such as a Bluetooth™ interface, a WiFi interface, etc. Additionally, in some embodiments, the support structure 102 further includes one or more batteries or other portable power sources for powering the electrical components of the display system 100. In some embodiments, some or all of these components of the display system 100 are contained entirely or partially within an interior volume of the support structure 102, such as within the arms 104 within the region 112 of the support structure 102. Note that while an exemplary form factor is shown, it is understood that in other embodiments, the display system 100 may have a different shape and appearance than the eyeglass frames shown in FIG. 1 . It should be understood that instances of the term “or” herein refer to a non-exclusive definition of “or” unless otherwise stated. For example, as used herein, the phrase "X or Y" means "X, or Y, or both."

[0014] One or both of the lens elements 108, 110 are used by the display system 100 to provide an augmented reality (AR) display. In an AR display, rendered graphical content can be superimposed on or otherwise combined with a view of the real world as perceived by a user through the lens elements 108, 110. For example, laser light used to form a perceptible image or series of images can be projected by a laser projector in the display system 100 to a user's eye through a series of optical elements, such as a waveguide formed at least in part by corresponding lens elements, one or more scanning mirrors, and one or more optical repeaters. To this end, one or both of the lens elements 108, 110 include at least a portion of a waveguide that routes display light received by an input coupler of the waveguide to an output coupler of the waveguide, which outputs the display light toward the eye of a user of the display system 100. The display light is modulated and scanned onto the user's eye such that the user perceives the display light as an image. Additionally, each of the lens elements 108, 110 is sufficiently transparent to allow a user to see through the lens element and provide a view of the user's real-world environment such that the image appears superimposed on at least a portion of the real-world environment.

[0015] In some embodiments, the projector is a digital light processing-based projector, a scanning laser projector, or any combination of a modulatable light source, such as a laser or one or more light-emitting diodes (LEDs), and a dynamic reflector mechanism, such as one or more dynamic scanners or a digital light processor. In some embodiments, the projector includes multiple laser diodes (e.g., red, green, and blue laser diodes) and at least one scanning mirror (e.g., two one-dimensional scanning mirrors that can be microelectromechanical systems (MEMS)-based or piezoelectric-based). The projector is communicatively coupled to a controller and a non-transitory processor-readable storage medium or memory that stores processor-executable instructions and other data that, when executed by the controller, cause the controller to control the operation of the projector. In some embodiments, the controller is communicatively coupled to a processor (not shown) that controls the size of the projector's scanning area and the location of the scanning area and generates the content displayed on the display system 100. The projector scans light over a variable area designated as the FOV area 106 of the display system 100. The size of the scan area corresponds to the size of the FOV area 106, and the scan area location corresponds to the region of one of the lens elements 108, 110 where the FOV area 106 is visible to the user. It is desirable to have a wide FOV to accommodate the outcoupling of light over a range of degrees. Herein, the range of different user eye positions from which the display will be visible is referred to as the eyebox of the display.

[0016] In some embodiments, the projector routes light through first and second scanning mirrors, an optical repeater disposed between the first and second scanning mirrors, and a waveguide disposed at the output of the second scanning mirror. In some embodiments, at least a portion of the output coupler of the waveguide can overlap the FOV area 106. These aspects are described in further detail below.

[0017] 2 shows a schematic block diagram of a laser projection system 200 that projects an image directly onto a user's eye via laser light. The laser projection system 200 includes an optical engine 202, an optical scanner 204, and a waveguide 205. The optical scanner 204 includes a first scanning mirror 206, a second scanning mirror 208, and an optical repeater 210. The waveguide 205 includes an input coupler 212 and an output coupler 214, which in this example is optically aligned with the user's eye 216. In some embodiments, the laser projection system 200 is implemented in a wearable head-up display, such as the display system 100 of FIG. 1, or another display system.

[0018] The optical engine 202 includes one or more laser light sources configured to generate and output laser light 218 (e.g., visible laser light such as red, blue, and green laser light, and in some embodiments, invisible laser light such as infrared laser light). In some embodiments, the optical engine 202 is coupled to a driver or other controller (not shown) that controls the timing of the emission of laser light from the laser light sources of the optical engine 202 according to instructions received by the controller or driver from a coupled computer processor to modulate the laser light 218 that is perceived as an image when output to the retina of a user's eye 216.

[0019] For example, during operation of laser projection system 200, multiple laser light beams, each having a different wavelength, are output by laser light sources of optical engine 202 and then combined via a beam combiner (not shown) before being directed toward user's eye 216. Optical engine 202 modulates the intensity of each of the laser light beams so that the combined laser light reflects off a series of pixels of an image. The particular intensity of each laser light beam at any given time contributes to the corresponding color content and amount of brightness of the pixel represented by the combined laser light at that time.

[0020] In some embodiments, one or both of the first and second scanning mirrors 206 and 208 of the optical scanner 204 are MEMS mirrors. For example, the first scanning mirror 206 and the second scanning mirror 208 are MEMS mirrors that are driven by respective actuation voltages to oscillate during active operation of the laser projection system 200, thereby causing the first and second scanning mirrors 206 and 208 to scan the laser light 218. The oscillation of the first scanning mirror 206 causes the laser light 218 output by the optical engine 202 to be scanned through the optical repeater 210 and across the surface of the second scanning mirror 208. The second scanning mirror 208 scans the laser light 218 received from the first scanning mirror 206 toward the input coupler 212 of the waveguide 205. In some embodiments, the first scanning mirror 206 oscillates or otherwise rotates about a first axis 219 such that the laser light 218 is scanned in only one dimension (i.e., linearly) across the surface of the second scanning mirror 208. In some embodiments, the second scanning mirror 208 oscillates or otherwise rotates about a second axis 221. In some embodiments, the first axis 219 is tilted relative to the second axis 221.

[0021] In some embodiments, the input coupler 212 has a substantially rectangular profile and is configured to receive the laser light 218 and direct the laser light 218 into the waveguide 205. The input coupler 212 is defined by a smaller dimension (i.e., width) and a larger, orthogonal dimension (i.e., length). In embodiments, the optical repeater 210 is a line-scan optical repeater that receives the laser light 218 scanned in a first dimension (e.g., the first dimension corresponding to the smaller dimension of the input coupler 212) by the first scanning mirror 206, routes the laser light 218 to the second scanning mirror 208, and focuses (e.g., by collimation) the laser light 218 in the first dimension at an exit pupil plane of the optical repeater 210 beyond the second scanning mirror 208. As used herein, a "pupil plane" refers to a location along the optical path of the laser light through an optical system where the laser light is focused at an aperture along one or more dimensions. For example, the optical repeater 210 can be associated with one or more entrance pupil planes located along the optical path of the laser light through the optical system, where the laser light is focused to a virtual aperture before entering the optical repeater 210. For example, the optical repeater 210 can be associated with one or more exit pupil planes located along the optical path of the laser light through the optical system, where the laser light is focused to a virtual aperture along one or more dimensions after exiting the optical repeater 210. In some embodiments, the entrance pupil plane of the optical repeater 210 can be positioned coincident with the first scanning mirror 206. In some embodiments, the entrance pupil plane of the optical repeater 210 can be located at an intermediate location between the first scanning mirror 206 and the optical repeater 210. In some embodiments, the exit pupil plane of the optical repeater 210 can be positioned coincident with the second scanning mirror 208. In some embodiments, the exit pupil plane of the optical repeater 210 can be positioned coincident with the input coupler 212.

[0022] In some examples, the laser light is focused along a first dimension to a virtual aperture in a first entrance pupil plane (e.g., the laser light is focused along the x- and y-dimensions to a point or line along the z-dimension in a Cartesian coordinate system having an x-axis, a y-axis, and a z-axis) and along a second dimension to a virtual aperture in a second entrance pupil plane (e.g., the second dimension is substantially perpendicular to the first dimension), where the first and second entrance pupil planes are different in location. In some examples, the laser light is focused along a first dimension to a virtual aperture in a first exit pupil plane (e.g., the laser light is focused along the x- and y-dimensions to a point or line along the z-dimension in a Cartesian coordinate system having an x-axis, a y-axis, and a z-axis) and along a second dimension to a virtual aperture in an exit pupil plane (e.g., the second dimension is substantially perpendicular to the first dimension), where the first and second exit pupil planes are different in location. In other examples, the laser light is focused to a virtual aperture at a single entrance pupil plane along all dimensions (e.g., the laser light is focused to a virtual aperture along each of the x, y, and z dimensions) and to a virtual aperture at a single exit pupil plane along all dimensions. Although in this example, optical engine 202 is shown outputting a single beam of laser light 218 (which itself may be a combination of two or more light beams, each having a different polarization or wavelength) toward the first scanning mirror, in some embodiments, optical engine 202 is configured to generate and output two or more laser light beams toward the first scanning mirror, where the two or more laser light beams are angularly separated with respect to one another (i.e., they are "angularly separated laser light beams"). As explained above, two or more laser light beams are “angularly separated” when they propagate along different non-parallel, non-perpendicular optical paths that are tilted (e.g., angularly offset) relative to one another, and in some instances, the angular separation of the optical paths causes the two or more laser light beams to converge so that they overlap one another along one or more dimensions (e.g., such overlap corresponds to a virtual aperture in a pupil plane).

[0023] In this example, the possible optical paths of the laser light 218 are initially diverged along the first scanning dimension following reflection by the first scanning mirror 206, but these optical paths are later diverged by the optical repeater 208. Due to the concentration provided by optical repeater 210, the beams intersect at an exit pupil plane beyond second scanning mirror 208. For example, the width (i.e., smallest dimension) of a given exit pupil plane roughly corresponds to the diameter of the laser beam corresponding to that exit pupil plane. Thus, the exit pupil plane can be considered a "virtual aperture." In some embodiments, the exit pupil plane of optical repeater 210 coincides with input coupler 212. In some embodiments, the entrance pupil plane of optical repeater 210 coincides with first scanning mirror 206.

[0024] According to various embodiments, the optical repeater 210 includes one or more spherical, aspherical, parabolic, or freeform lenses that shape and relay the laser light 218 to the second scanning mirror 208, or includes a molded reflective repeater that includes two or more optical surfaces, including, but not limited to, spherical, aspherical, parabolic, or freeform lenses or reflectors (sometimes referred to herein as "reflective surfaces"), that shape and direct the laser light 218 to the second scanning mirror 208. The second scanning mirror 208 receives the laser light 218 and scans the laser light 218 in a second dimension. The second dimension corresponds to the long dimension of the input coupler 212 of the waveguide 205. In some embodiments, the second scanning mirror 208 causes an exit pupil plane of the laser light 218 to be swept along a line along the second dimension. In some embodiments, the input coupler 212 is positioned at or near a sweep line downstream from the second scanning mirror 208 so that the second scanning mirror 208 scans the laser light 218 as columns or rows across the input coupler 212.

[0025] In some embodiments, the optical engine 202 includes an edge-emitting laser (EEL) that emits laser light 218 having a substantially elliptical, non-circular cross-section, and the optical repeater 210 expands or minimizes the laser light 218 along one or both of a first direction (e.g., a major radius of the beam profile of the laser light 218) or a second direction (e.g., a minor radius of the beam profile of the laser light 218) to reshape (e.g., circularize) the laser light 218 before focusing the laser light 218 at the second scanning mirror 208. In some such embodiments, the surface of the mirror plate of the first scanning mirror 206 is elliptical and non-circular (e.g., similar in shape and size to the cross-sectional area of ​​the laser light 218). In other such embodiments, the surface of the mirror plate of the first scanning mirror 206 is circular.

[0026] The waveguide 205 of the laser projection system 200 includes an input coupler 212 and an output coupler 214. The term "waveguide," as used herein, will be understood to mean a combiner that transmits light from an input coupler (such as input coupler 212) to an output coupler (such as output coupler 214) using one or more of total internal reflection (TIR), special filters, or reflective surfaces. In some display applications, the light is a collimated image, and the waveguide transmits and replicates the collimated image to the eye. In general, the terms "input coupler" and "output coupler" will be understood to refer to any type of optical grating structure, including, but not limited to, a diffraction grating, a hologram, a holographic optical element (e.g., an optical element using one or more holograms), a volume diffraction grating, a volume hologram, a surface-relief diffraction grating, or a surface-relief hologram. In some embodiments, a given input or output coupler is configured as a transmission grating (e.g., a transmission diffraction grating or a transmission holographic grating) such that the input or output coupler transmits light and applies a designed optical function to the light while transmitting. In some embodiments, a given input or output coupler is a reflection grating (e.g., a reflection diffraction grating or a reflection holographic grating) such that the input or output coupler reflects light and applies a designed optical function to the light while reflecting. In this example, laser light 218 received at input coupler 212 is relayed to output coupler 214 via waveguide 205 using TIR. Laser light 218 is then output to user's eye 216 via output coupler 214. As discussed above, in some embodiments, waveguide 205 has an eyeglass form factor and a display system utilizing laser projection system 200 The optical system may be implemented as part of an eyeglass lens, such as lens element 108 or 110 (FIG. 1).

[0027] 2 , in some embodiments, additional optical components are included in any of the optical paths between the optical engine 202 and the first scan mirror 206, between the first scan mirror 206 and the optical repeater 210, between the optical repeater 210 and the second scan mirror 208, between the second scan mirror 208 and the input coupler 212, between the input coupler 212 and the output coupler 214, or between the output coupler 214 and the eye 216 (e.g., to shape the laser light for viewing by the user's eye 216). In some embodiments, a prism is used to steer the light from the second scan mirror 208 to the input coupler 212 so that the light is coupled into the input coupler 212 at an angle suitable for promoting propagation of the light in the waveguide 205 by TIR. Also, in some embodiments, an exit pupil expander such as a fold grating (e.g., exit pupil expander 304 of FIG. 3 described below) is positioned at an intermediate stage between input coupler 212 and output coupler 214 to receive light coupled into waveguide 205 by input coupler 212, expand the light, and redirect the light towards output coupler 214, which then couples the laser light out of waveguide 205 (e.g., towards the user's eye 216).

[0028] 3 illustrates an example of light propagation within the waveguide 205 of the laser projection system 200 of FIG. 2, according to some embodiments. As shown, light received via the input coupler 212, scanned along the scanning dimension 302, is directed to the exit pupil expander 304 and then routed to the output coupler 214 for output (e.g., toward a user's eye). In some embodiments, the exit pupil expander 304 expands one or more dimensions of the eyebox of a display system (e.g., the display system 100 of FIG. 1, the WHUDs 600, 702 of FIGS. 6 and 7) that includes the laser projection system 200 (e.g., relative to the dimensions of the display's eyebox in the absence of the exit pupil expander 304). In some embodiments, the input coupler 212 and the exit pupil expander 304 each include a respective one-dimensional diffraction grating (i.e., a diffraction grating extending along one dimension) that diffracts incident light in a particular direction depending on the angle of incidence of the incident light and the structural aspects of the diffraction grating. 3 shows a substantially ideal case in which input coupler 212 directs light straight down (relative to the currently shown view) in a first direction perpendicular to scanning dimension 302, and exit pupil expander 304 directs light to the right (relative to the currently shown view) in a second direction perpendicular to the first direction. It should be understood that, although not shown in this example, in some embodiments, the first direction in which input coupler 212 directs light is not exactly perpendicular to scanning dimension 302, but is slightly or substantially tilted.

[0029] 4 illustrates an exemplary embodiment of a laser projection system 200 in which the optical repeater 210 includes a molded reflective repeater. As shown, the laser projection system 200 includes a substrate 402 on which a beam combiner 404, a primary lens 406, and a mirror 408 are disposed. According to various embodiments, the substrate 402 is a printed circuit board (PCB) or another applicable substrate.

[0030] The optical engine 202 includes a set of one or more laser light sources 410 (e.g., laser diodes), such as the illustrated red laser light source 410-1, green laser light source 410-2, and blue laser light source 410-3, and a processor or other controller operates the optical engine 202 to modulate the intensity of each of the laser light sources 410 to provide a corresponding red, green, and blue light contribution to a corresponding pixel of an image being generated for display to a user. The primary lens 406 includes a corresponding number of collimation lenses (e.g., three for the three laser light sources 410 in the example above) that are interposed in the optical path between each laser light source 410 of the optical engine 202 and the beam combiner 404. For example, each laser light source 410 is collimated through the primary lens 406. , and output laser light of different wavelengths (e.g., corresponding to respective red, blue, and green wavelengths) that are combined in beam combiner 404 to generate the laser light that is projected by laser projection system 200 (i.e., laser light 218 shown in FIG. 2 ). Beam combiner 404 receives the individual laser light inputs and outputs the combined laser light 218 to mirror 408, which redirects laser light 218 onto a reflective surface 412 of first scanning mirror 206. First scanning mirror 206 scans laser light 218 into optical repeater 210 along a first scanning dimension.

[0031] In the example of FIG. 4 , optical repeater 210 is a molded reflective repeater that can be molded, for example, from a solid, transparent component (e.g., glass or an optical plastic such as Zeonex), with its reflective surfaces implemented as a mirror coating or metasurface. In some embodiments, one or more reflective surfaces of molded reflective repeater 1802 reflect light via TIR and, therefore, do not require a mirror coating or fabricated metasurface to reflect light. Such a mold can simplify the fabrication of laser projection system 200 by facilitating the incorporation of some or all of the optical surfaces of the repeater into a single element rather than several separate, distinct elements. Furthermore, in some embodiments, the use of a molded structure allows light to propagate through one or more regions of molded reflective repeater 1802 via TIR, rather than propagating light through these regions using a mirror coating.

[0032] Optical repeater 210 is configured to route laser light 218 toward reflective surface 414 of second scanning mirror 208. Second scanning mirror 208 scans laser light 218 across an input coupler (such as input coupler 212) of waveguide 205 along a second scanning dimension. In some embodiments, the second scanning dimension is perpendicular to a plane along which the laser light propagates through optical repeater 210.

[0033] 5 illustrates example paths that concurrent laser beams output by optical engine 202 may take through optical repeater 210 for embodiments in which optical repeater 210 is a molded reflective repeater. As shown, optical engine 202 outputs red laser beam 218-1, green laser beam 218-2, and blue laser beam 218-3 toward beam combiner 404. Beam combiner 404 combines the individual beams of laser beams 218-1, 218-2, and 218-3 into laser beam 218 and redirects laser beam 218 toward mirror 408. Mirror 408 reflects laser beam 218 onto first scanning mirror 206. First scanning mirror 206 scans laser beam 218 into optical repeater 210 along a first scanning dimension 502. The optical repeater 210 reflects the laser light 218 from reflective surfaces 504, 506, 508, and 510, and then outputs the laser light 218 toward the reflective surface 414 of the second scanning mirror 208. The second scanning mirror 208 then scans the laser light 218 across the input coupler 212 along a second scanning dimension 512, where the laser light 218 is focused onto the input coupler 212 at most or all of the achievable scan angles of the first scanning mirror 206. While in this example the beam combiner 404 is shown outputting a single beam of laser light 218, it should be understood that in some embodiments the beam combiner 404 is configured to output two or more angularly separated beams of laser light directed onto the first scanning mirror 206.

[0034] Figure 6 shows a portion of a WHUD 600 that includes the laser projection system 200 of Figure 2. In some embodiments, the WHUD 600 represents the display system 100 of Figure 1. The optical engine 202, the optical scanner 204, the input coupler 212, and a portion of the waveguide 205 are included in arm 602 of the WHUD 600 in this example.

[0035] The WHUD 600 includes an optical combiner lens 604 including a first lens 606, a second lens 608, and a waveguide 205, with the waveguide 205 disposed between the first lens 606 and the second lens 608. Light exiting through the output coupler 214 travels through the second lens 608 (e.g., corresponding to the lens element 110 of the display system 100). In use, the light exiting the second lens 608 enters the pupil of the eye 610 of a user wearing the WHUD 600, causing the user to perceive a displayed image carried by the laser light output by the optical engine 202. The optical combiner lens 604 is substantially transparent, allowing light from a real-world scene corresponding to the environment around the WHUD 600 to pass through the first lens 606, the second lens 608, and the waveguide 205 to reach the user's eye 610. In this way, the images or other graphical content output by the laser projection system 200, when projected onto the user's eye 610, are combined (e.g., overlaid) with real-world images of the user's environment, providing the user with an AR experience.

[0036] Although not shown in the illustrated example, in some embodiments, additional optical elements are included in any of the optical paths between the optical engine 202 and the input coupler 212, between the input coupler 212 and the output coupler 214, or between the output coupler 214 and the user's eye 610 (e.g., to shape the laser light for viewing by the user's eye 610). By way of example, a prism is used to steer light from the optical scanner 204 to the input coupler 212 so that the light is coupled into the input coupler 212 at an angle suitable for promoting propagation of the light in the waveguide 205 by TIR. Also, in some embodiments, an exit pupil expander (e.g., exit pupil expander 304), such as a fold grating, is positioned at an intermediate stage between the input coupler 212 and the output coupler 214 to receive the light coupled into the waveguide 205 by the input coupler 212, expand the light, and redirect the light towards the output coupler 214, which then couples the laser light out of the waveguide 205 (e.g., towards the user's eye 610).

[0037] 7 and 8 show two different perspective views, namely, partially transparent views 700 (FIG. 7) and 800 (FIG. 8), of a portion of a WHUD 702 that represents the WHUD 600 of FIG. 6 or the display system 100 of FIG. 1. The WHUD 702 includes an exemplary configuration of the laser projection system 200 of FIGS. 2, 4, and 5 for embodiments in which the optical repeater 210 is a molded reflective repeater. In some embodiments, the WHUD 702 corresponds to the display system 100 of FIG. 1, and the shown portion of the WHUD 702 corresponds to the region 112 of the display system 100.

[0038] As shown by view 700 in Figure 7 and view 800 in Figure 8, arm 704 of WHUD 702 houses optical engine 202, primary lens 406, first scan mirror 206, optical repeater 210, and at least a portion of substrate 402. Frame section 706 of WHUD 702 houses second scan mirror 208, first scan mirror 206, optical repeater 210, and a portion of substrate 402. As shown by view 700 in Figure 7, input coupler 212 and output coupler 214 of waveguide 205 (not fully shown in the views of Figures 7 and 8) are each embedded in or otherwise disposed on lens 708 (e.g., one embodiment of lens 110 in Figure 1). As explained above, the laser light output by the optical engine 202 (e.g., laser light 218 in FIG. 5 ) is routed to the input coupler 212 via at least the first scanning mirror 206, the optical repeater 210, and the second scanning mirror 208. The first scanning mirror 206 oscillates or otherwise rotates to scan the laser light along a first scanning dimension, and the second scanning mirror 208 oscillates or otherwise rotates to scan the laser light along a second scanning dimension perpendicular to the first scanning dimension. The laser light reflected by the second scanning mirror 208 is focused into a line at the input coupler 212. The relayed laser light received at the input coupler 212 is transmitted to the output coupler 212 via the waveguide 205. 14. The laser light received at output coupler 214 is then directed out of waveguide 205 (e.g., towards the eye of a user of WHUD 702).

[0039] 9 shows an exemplary perspective view of a laser projection system 900 (one embodiment of laser projection system 200 of FIG. 2) that uses two angularly separated laser light beams to carry image information for projection. In this example, the perspective view of laser projection system 900 is provided with respect to a three-dimensional Cartesian coordinate system having orthogonal x-, y-, and z-axes, where the perspective view provides a perspective looking down the positive z-axis.

[0040] Optical engine 202 includes two or more laser light sources configured to each output a different wavelength of laser light toward beam combiner 404. Beam combiner 404 combines the wavelengths of laser light output by optical engine 202 into a first laser light beam 902 and a second laser light beam 904 that are angularly separated from one another (e.g., by an angle between about 0 degrees and about 10 degrees) and outputs first and second laser light beams 902 and 904 (sometimes referred to herein as first and second angularly separated laser light beams 902 and 904) toward first scanning mirror 206. In some embodiments, first laser light beam 902 and second laser light beam 904 are each considered an "aggregate" laser light beam because they include multiple wavelengths of laser light combined via beam combiner 404. In this example, only the central rays of the first and second laser light beams 902 and 904 are shown, but it should be understood that the first and second laser light beams 902 and 904 are scanned across their respective scan regions by the first and second scanning mirrors 206 and 208, and the central rays shown are centered within the scan regions. The first and second laser light beams 902 and 904 converge along the x and y dimensions (with respect to the axes shown) and overlap (e.g., overlap in the z dimension, having the same or substantially the same z coordinate at one or more overlap points) at a reflective surface of the first scanning mirror 206 (e.g., reflective surface 412 in FIG. 4 ), which corresponds to a first entrance pupil plane of the optical repeater 210. According to various embodiments, other entrance pupil planes corresponding to the concentration of the first and second laser light beams 902 and 904 onto the virtual aperture along other dimensions or planes (e.g., dimensions or planes substantially perpendicular to the x-y dimensions) may be disposed at the same or substantially the same location along the optical paths of the first and second laser light beams 902 and 904 as the first entrance pupil plane, or may instead be disposed at other locations along these optical paths. In some embodiments, the first axis 219 about which the first scanning mirror 206 is configured to oscillate is aligned or substantially aligned along the x-y dimensions and perpendicular or substantially perpendicular to the z-axis.

[0041] The first scanning mirror 206 scans the first and second laser light beams 902 and 904 into the optical repeater 210 along a first scanning dimension (e.g., scanning dimension 302 in FIG. 3 , first scanning dimension 502 in FIG. 5 ) that corresponds to or substantially corresponds to an xz dimension that is substantially orthogonal to the xy dimension. Upon reflection by the first scanning mirror 206, the optical paths of the first and second laser light beams 902 and 904 again diverge and become angularly separated along the xy dimension. In some embodiments, the optical repeater 210 expands each of the first and second laser light beams 902 and 904 along one or more dimensions (e.g., circularizes each of the first and second laser light beams 902 and 904). According to various embodiments, different levels (i.e., magnitudes) of expansion (sometimes referred to as beam expansion) of the first and second laser light beams 902 and 904 along their respective non-scanning dimensions are applied by the reflective surfaces of the optical repeater 210. As used herein, two dimensions (e.g., lines, planes, directions, etc.) are considered "substantially orthogonal" or "substantially perpendicular" to one another when they are orthogonal or perpendicular to one another within about 15 degrees. The optical repeater 210 transmits the first and second laser light beams 902 and 904 to the second scanning The first and second laser light beams 902 and 904 are relayed to the scanning mirror 208 to focus the first and second laser light beams 902 and 904 along the xy dimensions and the scanning area of ​​each of the first and second laser light beams 902 and 904 in the z dimension along their respective propagation directions.

[0042] In this example, the first and second laser light beams 902 and 904 are incident on two separate locations on the reflective surface (e.g., reflective surface 414 in FIG. 4 ) of the second scan mirror 208 (i.e., the exit pupil plane of the optical repeater along the x- and y-dimensions is not disposed on the second scan mirror 208). However, it should be understood that in some embodiments, the first and second laser light beams 902 and 904 are instead incident on the reflective surface of the second scan mirror 208 in an area that is substantially the same as or at least partially overlaps with the area of ​​the reflective surface of the second scan mirror 208, and in some such embodiments, the reflective surface of the second scan mirror 208 acts as the exit pupil plane of the optical repeater 210 along the x- and y-dimensions. As used herein, two areas (e.g., the area of ​​an incident region and the area of ​​a reflective surface, the areas of two incident regions, etc.) are considered "substantially the same" if a first of the two areas is within about 66% to about 133% of the size of a second of the two areas. The second scanning mirror 208 scans the first and second laser light beams 902 and 904 along the x-y dimension (e.g., the second scanning dimension 512 in FIG. 5) toward the input coupler 212.

[0043] In this example, upon reflection by the second scanning mirror 208, the first and second laser light beams 902 and 904 converge along the x and y dimensions and overlap (e.g., overlap in the z dimension) at a first exit pupil plane of the optical repeater 210 at the input coupler 212. However, in embodiments in which the exit pupil plane of the optical repeater 210 is disposed at or substantially at the reflective surface of the second scanning mirror 208, the first and second laser light beams 902 and 904 instead diverge along the x and y dimensions after reflection by the second scanning mirror 208 and impinge at different locations along the input coupler 212. According to various embodiments, other exit pupil planes corresponding to the convergence of the first and second laser light beams 902 and 904 to the virtual aperture along other dimensions or planes (e.g., dimensions or planes substantially perpendicular to the x-y dimensions, such as the z-dimension) may be disposed at the same or substantially the same location as the first exit pupil plane along the optical paths of the first and second laser light beams 902 and 904, or may alternatively be disposed at other locations along these optical paths. In addition, the respective scanning regions of the first and second laser light beams 902 and 904 each converge with respect to the z-dimension along their respective propagation directions, such that the second scanning mirror 208 scans each of the first and second laser light beams 902 and 904 along a respective substantially one-dimensional path (e.g., in a respective line or arc) at the input coupler 212 (e.g., at the first exit pupil plane 908). As used herein, a "substantially one-dimensional" path refers to a path that follows a single straight or curved line (eg, an arc).

[0044] 9, the first and second laser light beams 902 and 904 input to the optical scanner 204 are shown as angularly separated and converging along the x- and y-axes at a first entrance pupil plane at the first scanning mirror 206 and a first exit pupil plane at the input coupler 212, but in some alternative embodiments of the laser projection system 900, the first and second laser light beams 902 and 904 are not angularly separated by a substantially non-zero amount, but are instead parallel or collinear. In such alternative embodiments, each of the first and second laser light beams 902 and 904 undergoes independent convergence (i.e., of the light of each individual beam relative to, but not necessarily relative to, the other beams) to a virtual aperture along the x- and y-axes at the first entrance pupil plane and the first exit pupil plane.

[0045] FIG. 10 shows a laser light beam 1002 (sometimes referred to herein as the “first laser beam”). 1 shows an exemplary perspective view 1000 of a portion of a laser projection system (one embodiment of the laser projection system 200 of FIG. 2 ) in which a first laser light beam 1002 (referred to as “first laser light beam 1002”) is incident on the reflective surface 414 of the second scanning mirror 208 at an angle of incidence 1010, represented here as θ, with respect to the plane along which the reflective surface 414 is oriented (sometimes referred to herein as the plane of the reflective surface 414). In this example, the first laser light beam 1002 has a beam diameter 1012 and an angle of incidence 1010 such that the area of ​​incidence of the first laser light beam 1002 on the second scanning mirror 208 is entirely within the boundary defined by the reflective surface 414. That is, all or substantially all of the first laser light beam 1002 is incident on the reflective surface 414. In some embodiments, the first laser light beam 1002 is an aggregate laser light beam that includes multiple laser light wavelengths that have been previously combined, for example, using a beam combiner (e.g., an embodiment of the beam combiner 404 in Figures 4, 9).

[0046] In this example, the optical path of first laser light beam 1002 is shown via central ray 1006, first boundary ray 1004, and second boundary ray 1008. For example, the light of first laser light beam 1002 is substantially or completely disposed within the area defined by first boundary ray 1004 and second boundary ray 1008, and is centered or substantially centered along central ray 1006. The shortest distance between first boundary ray 1004 and second boundary ray 1008 defines beam diameter 1012.

[0047] As shown, the second scanning mirror 208 includes a reflective surface 414 having a width 1014. The angle of incidence 1010 of the first laser light beam 1002 at the reflective surface 414 is defined here as the angle θ, relative to the xy plane, between the plane of the reflective surface 414 and the central ray 1006 of the first laser light beam 1002 as the first laser light beam 1002 approaches the reflective surface 414. The beam diameter 1012, the angle of incidence 1010, and the width 1014 of the reflective surface 414 collectively determine whether the incidence area of ​​the first laser light beam 1002 on the second scanning mirror 208 is located entirely on the reflective surface 414 or whether a portion of the incidence area misses the reflective surface. In some embodiments, the beam diameter 1012 of the first laser light beam 1002 is set via an expansion of the first laser light beam 1002 applied to the optical repeater 210 (e.g., via one or more reflective surfaces thereof having an optical prescription that results in such expansion).

[0048] While the second scan mirror 208 is shown in a particular orientation (i.e., a first orientation) herein, it should be understood that the reflective surface 414 of the second scan mirror 208 oscillates or otherwise rotates (e.g., about an axis in the z dimension, such as the second axis 221 shown in FIG. 2 ). In some embodiments, the reflective surface 414 oscillates or otherwise rotates independently of the body of the second scan mirror 208, while in other embodiments, the reflective surface 414 oscillates or otherwise rotates with all or a portion of the body of the second scan mirror 208. Such rotation of the reflective surface 414 typically changes the size of the incidence area of ​​the first laser light beam 1002 on the reflective surface 414 due to the resulting change in the angle of incidence 1010 (e.g., the size of the incidence area decreases as the angle of incidence 1010 approaches perpendicular to the reflective surface 414 and increases as the angle of incidence 1010 approaches parallel to the reflective surface 414). In some embodiments, the beam diameter 1012 of the first laser light beam 1002 is set so that the incidence area of ​​the first laser light beam 1002 on the second scanning mirror 208 is disposed substantially (e.g., with at least about 80% of the first laser light beam 1002 incident on the reflective surface 414) or completely on the reflective surface 414 throughout each period of oscillation or rotation of the reflective surface 414. That is, the first laser light beam 1002 remains substantially or completely incident on the reflective surface 414 even when the reflective surface is at the extremes of its rotation or oscillation during operation. Herein, the maximum extent to which the scanning mirror rotates or oscillates in a given direction during operation is referred to as the extreme of its rotation or oscillation in that direction.

[0049] 11 shows an exemplary perspective view 1100 of a portion of a laser projection system (one embodiment of laser projection system 200 of FIG. 2) in which a laser light beam 1102 (sometimes referred to herein as “second laser light beam 1102”) is incident on a reflective surface 414 of a second scanning mirror 208 at an angle of incidence 1110, represented here as φ, with respect to the plane along which the reflective surface 414 is oriented. In some embodiments, the second laser light beam 1102 is an aggregate laser light beam including multiple laser light wavelengths that have previously been combined using, for example, a beam combiner (e.g., an embodiment of beam combiner 404 of FIGS. 4, 9).

[0050] 10 may be provided together as angularly separated laser light beams to second scanning mirror 208. In some embodiments, angle of incidence 1110 of second laser light beam 1102 is further from normal to the plane of reflective surface 414 than angle of incidence 1010 of first laser light beam 1002, resulting in a larger area of ​​incidence of second laser light beam 1102 on second scanning mirror 208 compared to the area of ​​incidence of first laser light beam 1002 on second scanning mirror 208 for examples in which second laser light beam 1102 and first laser light beam 1002 have the same or similar respective beam diameters.

[0051] In the first example, the second laser light beam 1102 has a beam diameter 1112 such that, for a given angle of incidence 1110, the incidence area of ​​the second laser light beam 1102 on the second scanning mirror 208 partially exceeds the boundary defined by the reflective surface 414. That is, in the first example, a portion of the second laser light beam 1102 misses (and is therefore not reflected by) the reflective surface 414, resulting in a reduced brightness of the image produced by the laser projection system. In some embodiments of the first example, the beam diameter 1112 of the second laser light beam 1102 is the same as or substantially the same as the beam diameter 1012 of the first laser light beam 1002. In some embodiments of the first example, the beam diameter 1116 is set via the expansion of the second laser light beam 1102 applied by the reflective surface of the optical repeater 210.

[0052] In the first example, the optical path of second laser light beam 1102 is shown via central ray 1106, first boundary ray 1104, and second boundary ray 1108. The light of second laser light beam 1102 is substantially or completely disposed within the area defined by first boundary ray 1104 and second boundary ray 1108, and is centered or substantially centered along central ray 1106. The shortest distance between first boundary ray 1104 and second boundary ray 1108 defines beam diameter 1112. As shown, a portion of the light of second laser light beam 1102 near boundary rays 1104 and 1108 misses reflective surface 414 due to the incident area of ​​second laser light beam 1102 exceeding width 1114 of reflective surface 414.

[0053] In the second example, second laser light beam 1102 has a beam diameter 1116 that is smaller, in terms of incidence angle 1110, than beam diameter 1112 of the first example, such that the incidence area of ​​second laser light beam 1102 on second scanning mirror 208 falls entirely within the boundary defined by reflective surface 414. That is, in the second example, all or substantially all of second laser light beam 1102 is incident on reflective surface 414. In some embodiments of the second example, beam diameter 1116 of second laser light beam 1102 is smaller than beam diameter 1012 of first laser light beam 1002.

[0054] In some embodiments of the second example, the first laser light beam 1002 and the second Laser light beams 1102 are initially generated with matching or substantially matching beam diameters, and different respective levels of expansion are applied to each of first laser light beam 1102 and second laser light beam 1102 by the reflective surfaces of optical repeater 210, resulting in second laser light beam 1102 having a beam diameter 1116 that is smaller than beam diameter 1012 of first laser light beam 1002. In some embodiments of the second example, beam diameter 1116 is set by the expansion of second laser light beam 1102 applied by the reflective surfaces of optical repeater 210 such that the incidence areas of each of first laser light beam 1002 and second laser light beam 1102 are the same size or substantially the same size. By applying different levels of expansion to the first laser light beam 1002 and the second laser light beam 1102 in this manner, even if the first laser light beam 1002 and the second laser light beam 1102 are initially generated with the same or substantially similar beam diameters, the beam diameter of the second laser light beam 1102 can be made smaller than the diameter of the first laser light beam 1002 to account for the difference in the incidence angles 1010 and 1110 of the first laser light beam 1002 and the second laser light beam 1102 at the second scanning mirror 208 and the corresponding difference in the incidence areas.

[0055] In the second example, the optical path of second laser light beam 1102 is shown via central ray 1106, third boundary ray 1118, and fourth boundary ray 1120. The light of second laser light beam 1102 is substantially or completely disposed within the area defined by third boundary ray 1118 and fourth boundary ray 1120, and is centered or substantially centered along central ray 1106. The shortest distance between third boundary ray 1118 and fourth boundary ray 1120 defines beam diameter 1116. As shown, when second laser light beam 1102 has beam diameter 1116, all or substantially all of second laser light beam 1102 is incident on reflective surface 414.

[0056] In both the first and second examples, the angle of incidence 1110 of the second laser light beam 1102 on the reflecting surface 414 is defined, relative to the xy plane, as the angle φ between the plane of the reflecting surface 414 and the central ray 1106 of the second laser light beam 1102 as the second laser light beam 1102 approaches the reflecting surface 414. The beam diameter 1112 or 1116, the angle of incidence 1110, and the width 1114 of the reflecting surface 414 collectively determine whether the incident area of ​​the second laser light beam 1102 on the second scanning mirror 208 is located entirely on the reflecting surface 414 or whether a portion of the incident area misses the reflecting surface.

[0057] 10 (e.g., to facilitate comparison between the respective angles of incidence 1110 and 1110). As explained above, rotation of the reflective surface 414 typically changes the size of the incidence area of ​​the second laser light beam 1102 at the reflective surface 414 due to the resulting change in the angle of incidence 1110 (e.g., the size of the incidence area decreases as the angle of incidence 1110 approaches perpendicular to the reflective surface 414 and increases as the angle of incidence 1110 approaches parallel to the reflective surface 414). In some embodiments, the beam diameter 1116 of the second laser light beam 1102 is set such that the incidence area of ​​the laser light beam 1102 on the second scanning mirror 208 is disposed substantially (e.g., with 90% or more of the second laser light beam 1102 incident on the reflective surface 414) or entirely on the reflective surface 414 throughout each period of oscillation or rotation of the reflective surface 414. That is, the second laser light beam 1102 remains substantially or entirely incident on the reflective surface 414 even when the reflective surface is at extremes of rotation or oscillation during operation.

[0058] FIG. 12 shows an exemplary perspective view 1200 of a portion of a laser projection system (one embodiment of the laser projection system 200 of FIG. 2), in which a laser light beam 1202 (sometimes referred to herein as the “first laser light beam 1202,” and similar to the first laser light beam 1202 of FIG. 10) is projected. Following reflection from reflective surface 412 of first scanning mirror 206, laser light beam 1202 (which is one embodiment of laser light beam 1002) travels along the optical path shown, impinging on first reflective surface 1204, then on second reflective surface 1206, and then on reflective surface 414 of second scanning mirror 208. Second scanning mirror 208 scans first laser light beam 1202 along a path (e.g., a line or an arc) at input coupler 212. First reflective surface 1204 and second reflective surface 1206 are reflective surfaces of an optical repeater, such as, for example, the embodiment of optical repeater 210 of any of FIGS. 2, 4, 5, 7, 8, and 9.

[0059] First reflective surface 1204 is configured to focus first laser light beam 1202 to an intermediate pupil plane 1208 in the x and y dimensions. The beam width of first laser light beam 1202 then expands in the x and y dimensions until it encounters second reflective surface 1206. Second reflective surface 1206 collimates first laser light beam 1202 and reflects first laser light beam 1202 towards second scanning mirror 208. According to various embodiments, either or both of first reflective surface 1204 and second reflective surface 1206 have an optical prescription that effectively expands first laser light beam 1202. That is, the magnification caused by either or both of the first and second reflective surfaces 1204 and 1206 causes the first laser light beam 1202 to have a larger beam diameter in the first dimension after being reflected by the second reflective surface 1206 compared to the beam diameter in the first dimension of the first laser light beam 1202 between the first scanning mirror 206 and the first reflective surface 1204. Here, the beam diameter of the first laser light beam 1202 in the "first dimension" refers to the diameter of the first laser light beam 1202 along the x- and y-dimensions, or along a dimension substantially perpendicular to the scanning dimension of the first scanning mirror 206. The amount of magnification applied to the beam diameter of the first laser light beam 1202 in the first dimension by either or both of the first and second reflective surfaces 1204 and 1206 is sometimes referred to herein as a "first magnification level."

[0060] 13 shows an exemplary perspective view 1300 of a portion of a laser projection system (one embodiment of laser projection system 200 of FIG. 2 ) in which laser light beam 1302 (sometimes referred to herein as “second laser light beam 1302” and is one embodiment of second laser light beam 1102 of FIG. 11 ) travels along the optical path shown, following reflection from reflective surface 412 of first scanning mirror 206, impinging on third reflective surface 1304, then fourth reflective surface 1306, and then reflective surface 414 of second scanning mirror 208. Second scanning mirror 208 scans second laser light beam 1302 along a path (e.g., a line or an arc) at input coupler 212. The third reflective surface 1304 and the fourth reflective surface 1306 are reflective surfaces of an optical repeater such as, for example, the optical repeater 210 embodiment of any of Figures 2, 4, 5, 7, 8 and 9.

[0061] The third reflective surface 1304 is configured to focus the second laser light beam 1302 to an intermediate pupil plane 1308 in the x and y dimensions. The beam width of the second laser light beam 1302 then expands in the x and y dimensions until it encounters the fourth reflective surface 1306. The fourth reflective surface 1306 collimates the second laser light beam 1302 and reflects it towards the second scanning mirror 208. According to various embodiments, either or both of the third reflective surface 1304 and the fourth reflective surface 1306 have an optical prescription that effectively expands the second laser light beam 1302. That is, the magnification caused by either or both of the third reflective surface 1304 and the fourth reflective surface 1306 causes the second laser light beam 1302 to have a larger beam diameter in the first dimension after being reflected by the fourth reflective surface 1306 compared to the beam diameter in the first dimension of the second laser light beam 1302 between the first scanning mirror 206 and the third reflective surface 1304. Here, the beam diameter of the second laser light beam 1302 in the "first dimension" refers to the beam diameter along the x-y dimension, or the dimension substantially perpendicular to the scanning dimension of the first scanning mirror 206. This refers to the diameter of second laser light beam 1302 along its origin. The amount of expansion applied to the beam diameter of second laser light beam 1302 in the first dimension by either or both of third reflective surface 1304 and fourth reflective surface 1306 is sometimes referred to herein as the "second expansion level."

[0062] 14 shows an exemplary perspective view 1400 of a portion of a laser projection system (one embodiment of laser projection system 200 of FIG. 2) including an embodiment of first laser light beam 1202 and first and second reflective surfaces 1204 and 1206 of the example of FIG. 12 and second laser light beam 1302 and third and fourth reflective surfaces 1304 and 1306 of the example of FIG. 13. As shown in this example, first laser light beam 1202 and second laser light beam 1302 are angularly separated from one another. Note that, as shown, the respective optical paths of first laser light beam 1202 and second laser light beam 1302 intersect at various points.

[0063] In this example, an optical repeater, such as the embodiment of optical repeater 210 in any of Figures 2, 4, 5, 7, 8, and 9, includes reflective surfaces 1204, 1206, 1304, and 1306. In some embodiments, each of reflective surfaces 1204, 1206, 1304, and 1306 is a separate reflective element, such as a mirror, a metasurface, etc. In some embodiments, each of reflective surfaces 1204, 1206, 1304, and 1306 is included as a surface of a molded reflective repeater (e.g., a monolithic molded reflective repeater).

[0064] Due to the angular separation of the first laser light beam 1202 and the second laser light beam 1302, the first laser light beam 1202 has a first angle of incidence (e.g., angle of incidence 1010 in FIG. 10 ) at the reflective surface 414 of the second scanning mirror 208 that is different from the second angle of incidence (e.g., angle of incidence 1110 in FIG. 10 ) of the second laser light beam 1302 at the reflective surface 414. In this example, the first angle of incidence of first laser light beam 1202 on reflective surface 414 is closer to perpendicular to the plane of reflective surface 414 than the second angle of incidence of second laser light beam 1302, such that the incidence area of ​​first laser light beam 1202 on second scanning mirror 208 is smaller than the incidence area of ​​second laser light beam 1302 if first laser light beam 1202 and second laser light beam 1302 have the same beam diameter when incident on second scanning mirror 208. To accommodate the difference in the respective angles of incidence of the first laser light beam 1202 and the second laser light beam 1302 on the second scanning mirror 208, as shown, the first laser light beam 1202 and the second laser light beam 1302 initially have similar or matching beam diameters, but a first level of expansion is applied to the beam diameter of the first laser light beam 1202 in a first dimension (i.e., the x- and y-dimensions) by one or both of the first reflective surface 1204 and the second reflective surface 1206, while a second level of expansion is applied to the beam diameter of the second laser light beam 1302 in the first dimension by one or both of the third reflective surface 1304 and the fourth reflective surface 1306. For example, the first level of expansion is greater than the second level of expansion, such that when the first and second beams are incident on the second scanning mirror 208, the beam diameter of the first laser light beam 1202 in the first dimension (e.g., a beam diameter of approximately 1 mm) is greater than the beam diameter of the second laser light beam 1202 in the first dimension (e.g., a beam diameter of approximately 0.9 mm).In some embodiments, the first and second levels of expansion applied to the respective beam diameters of first laser light beam 1202 and second laser light beam 1302 by reflective surfaces 1204 and 1206, and reflective surfaces 1304 and 1306, respectively, are set so that the respective incidence areas of first laser light beam 1202 and second laser light beam 1302 on second scanning mirror 208 are equal or substantially equal in area, shape, or both, and each lie completely or substantially within the perimeter defined by reflective surface 414 of second scanning mirror 208. Angularly separated first laser light beams 1202 and 1302 may be configured to apply different levels of expansion in the first dimension. By applying this to the respective beam diameters of mirror 1202 and second laser light beam 1302, a larger incidence area of ​​second laser light beam 1302 on second scanning mirror 208 can be accommodated without increasing the size of reflective surface 414. This approach can be advantageous, for example, in the case of a laser projector where the size of the reflective surface (e.g., reflective surface 414) of the second scanning mirror is a limiting factor and it is not desirable to increase the size of the reflective surface to accommodate the larger incidence area of ​​the wider angle laser light beam (e.g., second laser light beam 1302) of the two angularly separated input laser light beams.

[0065] While first laser light beam 1202 and second laser light beam 1302 are shown in this example as having similar or the same respective initial beam diameters ("initial beam diameter" herein refers to the beam diameter of first and second laser light beam 1202 after reflection at first scanning mirror 206 and before reflection by reflective surfaces 1204 and 1304), it should be understood that in some embodiments, first laser light beam 1202 and second laser light beam 1302 instead have different initial beam diameters along at least a first dimension. In some such embodiments, a first level of expansion applied to first laser light beam 1202 by reflective surfaces 1204 and 1206 is different from a second level of expansion applied to second laser light beam 1302 by reflective surfaces 1304 and 1306, where the first level of expansion is different from the second level of expansion. The first level of magnification and the second level of magnification can be sized to cause the beam diameters of first laser light beam 1202 and second laser light beam 1302, after reflection by reflective surfaces 1206 and 1306, to have the same or substantially the same respective shapes, areas, or both as those of reflective surface 414 of second scanning mirror 208, given different respective angles of incidence of first laser light beam 1202 and second laser light beam 1302 on second scanning mirror 208.

[0066] In alternative embodiments, each of reflective surfaces 1204, 1206, 1304 and 1306 provides the same level of expansion to first and second laser light beams 1202 and 1302, and the initial beam diameters of first and second laser light beams 1202 and 1302 are selected to be different (e.g., in the first dimension) such that their incidence areas on second scanning mirror 208 are the same or substantially the same, and in some embodiments have the same area, shape or both as reflective surface 414 of second scanning mirror 208. That is, rather than applying different levels of expansion to laser light beams 1202 and 1302, laser light beams 1202 and 1302 are introduced into the optical repeater with different initial beam diameters, and the same level of expansion is applied to each of laser light beams 1202 and 1302 by reflective surfaces 1204, 1206, 1304 and 1306, such that, given the different angles of incidence of laser light beams 1202 and 1302 at second scanning mirror 208, the different initial beam diameters of laser light beams 1202 and 1302 cause the respective incidence areas of first laser light beam 1202 and second laser light beam 1302 to be the same or substantially the same, and in some embodiments have the same or substantially the same respective shape, area or both as that of reflective surface 414 of second scanning mirror 208.

[0067] The various embodiments described above are provided in the context of generating and routing laser light through an optical system, however, it should be understood that other applicable collimated light sources and corresponding light may be used in conjunction with the described embodiments in addition to or instead of such laser light and corresponding laser light sources.

[0068] It should be noted that not all operations or elements described above in the general description are required, that certain operations or portions of devices may not be required, and that one or more additional operations may be performed or elements may be included in addition to those described. Furthermore, the order in which operations are listed is not necessarily the order in which they are performed. Also, concepts have been described with reference to specific embodiments. However, those skilled in the art will recognize that various modifications and changes can be made without departing from the scope of the present disclosure as set forth in the following claims. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present disclosure.

[0069] Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, benefits, advantages, solutions to problems, and any features that can cause any benefit, advantage, or solution to occur or become more pronounced should not be construed as critical, necessary, or essential features of any or all claims. Moreover, the specific embodiments disclosed above are merely exemplary, as the disclosed subject matter may be modified and implemented in various but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. No limitations are intended to the details of construction or design shown herein, other than as described in the appended claims. It is therefore apparent that the specific embodiments disclosed above may be altered or modified, and all such variations are considered within the scope of the disclosed subject matter. Accordingly, the protection sought herein is as set forth in the appended claims.

Claims

1. 1. A laser projection system comprising: an optical repeater configured to receive and relay a first laser light beam and a second laser light beam and to apply different levels of expansion to the first laser light beam and the second laser light beam, respectively, to generate a first expanded laser light beam and a second expanded laser light beam; the first laser light beam and the second laser light beam are angularly separated, and the first expanded laser light beam and the second expanded laser light beam are scanned into the optical repeater; the laser projection system The laser projection system further comprising a first scanning mirror configured to receive the expanded first laser light beam and the expanded second laser light beam from the optical repeater.

2. 10. The laser projection system of claim 1, further comprising a second scanning mirror configured to scan the first expanded laser light beam and the second expanded laser light beam into the optical repeater.

3. The optical repeater comprises: a first reflective surface configured to apply a first level of magnification to the first laser light beam; a second reflective surface configured to apply a second level of magnification to the second laser light beam; 3. The laser projection system of claim 1 or claim 2, comprising:

4. 4. The laser projection system of claim 3, wherein the optical repeater is a molded reflective repeater, the first reflective surface is a first reflective surface of the molded reflective repeater, and the second reflective surface is a second reflective surface of the molded reflective repeater.

5. 5. The laser projection system of claim 1, wherein the first expanded laser light beam has a first incidence area on the first scanning mirror and the second expanded laser light beam has a second incidence area on the first scanning mirror, the first incidence area being substantially similar in area to the second incidence area.

6. 6. The laser projection system of claim 5, wherein the first scanning mirror is configured to receive the first expanded laser light beam at a first angle of incidence and to receive the second expanded laser light beam at a second angle of incidence, the first angle of incidence being different from the second angle of incidence.

7. 6. The laser projection system of claim 5, wherein the first entrance area and the second entrance area are each bounded by a reflective surface of the first scanning mirror.

8. A near-eye display comprising the laser projection system according to any one of claims 1 to 7, an eyeglass frame including at least a portion of the laser projection system; and a spectacle lens; The near-eye display, wherein the laser projection system is configured to output the first laser light beam and the second laser light beam through at least a portion of the eyeglass lens.

9. A near-eye display, a laser projection system, the laser projection system comprising: an optical repeater configured to receive the angularly separated laser light beams, apply different levels of expansion to the angularly separated laser light beams, and repeat the expanded angularly separated laser light beams; a scanning mirror configured to receive the expanded, angularly separated laser light beams from the optical repeater and to scan the expanded, angularly separated laser light beams; Near-eye display.

10. the angularly separated laser light beams include a first laser light beam and a second laser light beam, and the optical repeater comprises: a first reflective surface configured to apply a first level of magnification to the first laser light beam; a second reflective surface configured to apply a second level of magnification to the second laser light beam; The near-eye display of claim 9 , comprising:

11. 11. The near-eye display of claim 10, wherein the optical repeater is a molded reflective repeater, the first reflective surface is a first reflective surface of the molded reflective repeater, and the second reflective surface is a second reflective surface of the molded reflective repeater.

12. 11. The near-eye display of claim 10, wherein the first laser light beam has a first incident area on the scanning mirror and the second laser light beam has a second incident area on the scanning mirror, the first incident area being substantially similar in area to the second incident area.

13. 13. The near-eye display of claim 12, wherein the scanning mirror is configured to receive the first laser light beam at a first angle of incidence and the second laser light beam at a second angle of incidence, the first angle of incidence being different from the second angle of incidence.

14. 1. A method comprising: receiving angularly separated laser light beams from a first scanning mirror using an optical repeater; applying different levels of magnification to each of the angularly separated laser light beams using the optical repeater; relaying the expanded angularly separated laser light beams to a second scanning mirror using the optical repeater; A method comprising:

15. receiving the expanded angularly separated laser light beam from the optical repeater using the second scanning mirror; 15. The method of claim 14, wherein a first one of the expanded angularly separated laser light beams has a first angle of incidence and a first area of ​​incidence on the second scanning mirror, and a second one of the expanded angularly separated laser light beams has a second angle of incidence and a second area of ​​incidence on the second scanning mirror.

16. applying different levels of magnification to each of the angularly separated laser light beams using the optical repeater; a first beam diameter of the first laser light beam using a first reflective surface of the optical repeater; applying a first level of magnification to applying a second level of expansion to a second beam diameter of the second laser light beam using a second reflective surface of the optical repeater; 16. The method of claim 15, comprising:

17. 17. The method of claim 16, wherein the first incident region has a first area defined at least in part by the first beam diameter and the first angle of incidence, and the second incident region has a second area defined at least in part by the second beam diameter and the second angle of incidence, and the first area is substantially similar to the second area.

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