EMITTER SYSTEM ASSEMBLY AND FORMATION METHODS, DISPLAYS, AUGMENTED REALITY SYSTEMS, AND MICRO LED DEVICES

Abstract

The emitter system assembly includes an emitter that provides optical radiation, a cavity at least partially surrounding the emitter, an aperture configured to transmit at least a portion of the optical radiation from the emitter, and a lenslet in optical communication with the aperture. The cavity includes a reflector for reflecting the optical radiation within the cavity toward the aperture. Furthermore, the cavity, aperture, and lenslet are configured to cooperate to provide an optical output having optical characteristics suitable for coupling to a projector. In a further aspect, the optical characteristics include at least one of a predetermined output direction and a solid angle. In another aspect, the emitter system includes a low index material, an anti-reflective layer, and / or an optical containment structure around the emitter.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 180,840, filed April 28, 2021, and U.S. Provisional Patent Application No. 63 / 254,959, filed October 12, 2021, the disclosures of each of which are incorporated by reference in their entirety into this application. [Background technology]

[0002] background Aspects of the present disclosure relate generally to light emitting diodes (LEDs), and more specifically to assemblies that enhance light extraction from micro light emitting diodes (micro LEDs).

[0003] Recent advances in light emitting diode (LED) technology have enabled the formation of high density display devices incorporating arrays of micro LEDs, each having an emitter pitch on the order of a few microns to a fraction of a micron. For example, WO2019209945A1 discloses various configurations of micro LED-based light field displays.

[0004] To illustrate the contrast between conventional displays and microLED-based displays, Figure 1 shows a conventional display 110 having an array 120 of light emitting elements 125, best seen in inset 130. The light emitting elements 125, which may be conventional LEDs as previously described, may all emit light at the same wavelength or may be arranged in a pattern of LEDs emitting at two or more wavelengths. For example, the array 120 may include LEDs emitting at red, green, and blue wavelengths in the visible spectrum and arranged in a regular pattern.

[0005] 1, the light emitting elements 125 may be arranged in a Q×P array across the area of ​​the display 110, where Q is the number of rows of light emitting elements 125 in the array and P is the number of columns of light emitting elements 125 in the array. Although not shown, in addition to the light emitting elements 125, a conventional display 110 may include a backplane that includes various electrical traces and contacts configured to selectively provide power to one or more of the light emitting elements 125.

[0006] FIG. 2 illustrates a light field display 210 having an array 220 of superlaces 225, as shown in a first inset 230. Additionally, as shown in a second inset 240, each superlace 225 includes a sublace 245. Each one of the sublaces 245 may be a micro-LED, as previously described. That is, each superlace 225 may correspond in size with the light emitting element 125 of FIG. 1, including a plurality of sublaces 245 formed from micro-LEDs having an emitter pitch of a few microns or a fraction of a micron. In the example illustrated in FIG. 2, each superlace 225 is shown to have an approximately square shape with each side having a superlace pitch 227. Each superlace 225 may be configured to emit light in a single wavelength range (e.g., red, green, blue wavelength ranges) or across a color range (e.g., across at least a portion of the visible electromagnetic wavelength range).

[0007] In the example shown in FIG. 2, the superlaces 225 are arranged in an N×M array, where N is the number of rows of superlaces 225 in the array and M is the number of columns of superlaces 225 in the array. As shown in FIG. 2, each one of the superlaces 225 includes a number of sublaces 245. Each one of the sublaces 245 may include, for example, a micro LED that emits at red, green, or blue wavelengths in the visible spectrum and may be arranged in a regular pattern. In one example, the sublaces 245 of different colors may be monolithically integrated on a common substrate, and each one of the micro LEDs in the sublaces 245 may range from a fraction of a micron to about 100 microns.

[0008] 3 illustrates an embodiment of light steering for the superaxels 225. As shown in inset 330, each one of the superaxels 225 may include light steering optics 340. In the example shown in FIG. 3, each light steering optics 340 is shown to have a lens pitch 345 on the order of the size of one of the superaxels 225.

[0009] While microLED-based displays enable new applications, various improvements are still possible to maximize the performance of each microLED and the overall display. In particular, compact microLED arrays for augmented reality / virtual reality (AR / VR) and other near-eye display applications require high-brightness light output with highly efficient light extraction. Summary of the Invention

[0010] Overview of the embodiment The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all possible aspects, and is not intended to identify key or critical elements of all aspects or to delineate the scope of some or all aspects. Its purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description presented later.

[0011] In one aspect of the disclosure, an emitter system assembly for providing a light output to a projector is disclosed. The emitter system assembly includes an emitter for providing light radiation, a cavity at least partially surrounding the emitter, an aperture configured to transmit at least a portion of the light radiation from the emitter, and a lenslet in optical communication with the aperture. The cavity includes a reflector for reflecting the light radiation within the cavity toward the aperture. Furthermore, the cavity, the aperture, and the lenslet are configured to cooperate to provide a light output having optical properties suitable for coupling into a projector.

[0012] In a further aspect of the present disclosure, the optical characteristic includes at least one of a predetermined output direction and a solid angle.

[0013] In a further aspect of the disclosure, an emitter system assembly for providing a light output to a projector includes a first emitter providing a first light radiation, a second emitter providing a second light radiation, a first cavity at least partially surrounding the first emitter, a second cavity at least partially surrounding the second emitter, a first aperture configured to transmit at least a portion of the first light radiation from the first emitter, a second aperture configured to transmit at least a portion of the second light radiation from the second emitter, and a lenslet in optical communication with the first and second apertures. The first cavity includes a first reflector for reflecting the first light radiation within the first cavity toward the first aperture. The second cavity includes a second reflector for reflecting the second light radiation within the second cavity toward the second aperture. The first cavity, the first aperture, the second cavity, the second aperture, and the lenslet are configured to cooperate to provide first and second optical emissions to contribute to a light output having optical characteristics suitable for coupling into a projector.

[0014] In yet another aspect of the present disclosure, an emitter system assembly for providing a light output to a projector includes a first emitter providing a first light radiation, a second emitter providing a second light radiation, a cavity at least partially surrounding the first and second emitters, an aperture configured to transmit at least a portion of the first and second light radiation from the first and second emitters, and a lenslet in optical communication with the aperture. The cavity includes a reflector for reflecting the first and second light radiation within the cavity toward the aperture. Further, the cavity, the aperture, and the lenslet are configured to cooperate to provide a light output having optical properties suitable for coupling into a projector.

[0015] In yet another aspect of the present disclosure, a method for forming an emitter system assembly includes forming an emitter array on an emitter substrate, attaching the emitter substrate to a backplane, forming an array of cavities and apertures aligned with the emitter array, and attaching a lenslet array aligned with the array of apertures.

[0016] In yet another aspect of the present disclosure, a low index material having a lower index of refraction than the material forming the cavity is incorporated around at least a portion of the opening.

[0017] In another aspect of the present disclosure, one or more anti-reflective layers are incorporated into at least one of the cavity and the opening.

[0018] In a further aspect of the present disclosure, the emitter substrate incorporates a conductive material arranged to function as a cathode shared between two or more emitters.

[0019] In another aspect of the present disclosure, the emitter system includes a light confinement feature around the emitter. In one example, the light confinement feature includes one or more reflective layers surrounding the emitter. In one aspect, the light confinement feature is formed from a structure including a metal layer or a reflective dielectric stack.

[0020] The accompanying drawings depict only some implementations and therefore should not be considered limiting of the scope. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 illustrates an example of a display having a plurality of pixels according to an aspect of the present disclosure. [Diagram 2] FIG. 2 illustrates an example of a light field display having a plurality of pixels according to an aspect of the present disclosure. [Diagram 3] FIG. 2 illustrates an example of a light field display having a plurality of pixels according to an aspect of the present disclosure. [Figure 4] FIG. 1 illustrates a general configuration for extracting light from an LED according to an embodiment of the present disclosure. [Diagram 5] 1A-1C illustrate examples of light extraction features according to aspects of the present disclosure. [Figure 6] 1A-1C illustrate examples of light extraction features according to aspects of the present disclosure. [Figure 7] 1A-1C illustrate examples of light extraction features according to aspects of the present disclosure. [Figure 8] FIG. 1 illustrates an example of a configuration for extracting light from an array of micro LEDs according to an embodiment of the present disclosure. [Figure 9] FIG. 1 illustrates an example of a configuration for extracting light from an array of micro LEDs according to an embodiment of the present disclosure. [Figure 10] FIG. 1 illustrates an example of a configuration for extracting light from an array of micro LEDs according to an embodiment of the present disclosure. [Figure 11] 1 is a flowchart illustrating a process for forming light extraction features of a micro-LED according to an embodiment of the present disclosure. [Figure 12] 13A-13D illustrate further examples of light extraction features according to aspects of the present disclosure. [Figure 13] 13A-13D illustrate further examples of light extraction features according to aspects of the present disclosure. [Figure 14] FIG. 1 illustrates a partial cross-sectional view of an emitter array with light extraction and shared cathode functionality according to an aspect of the present disclosure. [Figure 15] FIG. 1 illustrates a partial top view of an emitter array with light extraction and shared cathode functionality according to an aspect of the present disclosure. [Figure 16] 1A-1C illustrate examples of light confinement features for confining light emitted by an emitter according to aspects of the present disclosure. [Figure 17] 1A-1C illustrate examples of light confinement features for confining light emitted by an emitter according to aspects of the present disclosure. [Figure 18] 1A-1C illustrate examples of light confinement features for confining light emitted by an emitter according to aspects of the present disclosure. [Figure 19]1A-1C illustrate examples of light confinement features for confining light emitted by an emitter according to aspects of the present disclosure. [Figure 20] FIG. 1 illustrates an exemplary process flow for forming an emitter having structures for light extraction according to an aspect of the present disclosure. [Figure 21] FIG. 1 illustrates an exemplary process flow for forming an emitter having structures for light extraction according to an aspect of the present disclosure. [Figure 22] FIG. 1 illustrates an exemplary process flow for forming an emitter having structures for light extraction according to an aspect of the present disclosure. [Diagram 23] FIG. 1 illustrates an exemplary process flow for forming an emitter having structures for light extraction according to an aspect of the present disclosure. [Figure 24] FIG. 1 illustrates an exemplary process flow for forming an emitter having structures for light extraction according to an aspect of the present disclosure. [Diagram 25] FIG. 1 illustrates an exemplary process flow for forming an emitter having structures for light extraction according to an aspect of the present disclosure. [Figure 26] FIG. 1 illustrates an exemplary process flow for forming an emitter having structures for light extraction according to an aspect of the present disclosure. [Figure 27] 1A-1C illustrate possible variations of emitters and emitter arrays having light extraction features according to aspects of the present disclosure. [Figure 28] 1A-1C illustrate possible variations of emitters and emitter arrays having light extraction features according to aspects of the present disclosure. [Figure 29] 1A-1C illustrate possible variations of emitters and emitter arrays having light extraction features according to aspects of the present disclosure. [Diagram 30] 1A-1C illustrate possible variations of emitters and emitter arrays having light extraction features according to aspects of the present disclosure. [Diagram 31] 1A-1C illustrate possible variations of emitters and emitter arrays having light extraction features according to aspects of the present disclosure. [Diagram 32] 1A-1C illustrate possible variations of emitters and emitter arrays having light extraction features according to aspects of the present disclosure. [Diagram 33] 1A-1C illustrate possible variations of emitters and emitter arrays having light extraction features according to aspects of the present disclosure. [Diagram 34] 1A-1C illustrate possible variations of emitters and emitter arrays having light extraction features according to aspects of the present disclosure. [Diagram 35] 1A-1C illustrate possible variations of emitters and emitter arrays having light extraction features according to aspects of the present disclosure. [Diagram 36] 1A-1C illustrate possible variations of emitters and emitter arrays having light extraction features according to aspects of the present disclosure. [Figure 37] 1A-1C illustrate possible variations of emitters and emitter arrays having light extraction features according to aspects of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Detailed Description The detailed description set forth below in conjunction with the accompanying drawings is intended to describe various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details to allow a thorough understanding of the various concepts. However, as will be apparent to one skilled in the art, these concepts may be practiced without these specific details. In some instances, well-known components are shown in block diagram form to avoid obscuring such concepts.

[0023] To effectively utilize the small size and high efficiency of micro-LEDs, it is necessary to extract as much light generated by each micro-LED as possible. Therefore, new configurations are desirable to improve the extraction of light generated by micro-LEDs.

[0024] 4 illustrates an exemplary configuration for improving light extraction from a light emitter, such as a micro-LED. As illustrated in FIG. 4, the emitter system 400 includes an emitter 410 for providing light emission. For example, the emitter 410 may be a conventional LED or a micro-LED based on quantum well (QW) technology, or another type of compact light emitter. The emitter 410 is at least partially surrounded by a surface 422 that defines an LED cavity. The surface 422 may be a single continuous concave surface. In an embodiment, the surface 422 is a surface of a substrate 420.

[0025] An etendue gate 430 provides a spatial aperture for light from the emitter 410 to be emitted towards mode matching optics 440 that are configured to shape the light from the LED cavity into an output 450 that meets the requirements of a particular application, such as for use in a projector device. Note that although the emitter 410 is shown as a solid block, it may include multiple layers, such as n-doped semiconductor layers, one or more quantum well structures, lattice matching layers, hole blocking layers, electron blocking layers, contact layers, and other materials known in the art of semiconductor emitter fabrication.

[0026] More specifically, surface 422 may be a highly reflective surface to confine the light generated by emitter 410. The geometry of the LED cavity may be tailored for a particular application to provide an optimal geometry for light coupling through etendue gate 430. Note that although the LED cavity is referred to as a "cavity," it may be filled with a material other than air, such as a solid semiconductor (e.g., gallium nitride) or another material (e.g., an insulator) that is substantially transparent to the light emitted by emitter 410.

[0027] The etendugate 430 may be a fixed or adjustable spatial aperture for efficiently coupling light from the LED cavity with the mode matching optics 440. The etendugate 430 may further include filters, for example, for selectively transmitting light having certain characteristics, for example, light incident on the etendugate 430 within a certain range of incidence angles, polarization states, wavelengths, resonant cavity modes, and other optical properties. For example, the etendugate 430 may include one or more non-reflective, low-reflective, or anti-reflective layers to enhance display contrast in the presence of external light. As an example, an array of emitter systems 400 may be formed into a display, with each emitter system generating light that contributes to an image generated by the display. In such a display, when external light is introduced into the display, each etendugate 430 may reflect the external light, compromising the image generated by the display. Such undesirable effects can be reduced by incorporating one or more non-reflective, low-reflective, or anti-reflective layers in the etendue gate 430 so that external light reaching the etendue gate 430 can be trapped within the LED cavity.

[0028] The mode matching optics 440 may include one or more refractive, reflective, or diffractive optics arranged in an imaging or non-imaging configuration. The mode matching optics 440 may be tuned to provide an output 450 that matches the acceptance light field of a particular application. For example, if the emitter system 400 is intended to provide optical radiation for use in a projector, such as for an augmented reality (AR) or virtual reality (VR) headset, the mode matching optics 440 may be configured to convert the light transmitted through the etendue gate 430 into an output 450 that best matches the acceptance criteria of the projector. Again, non-reflective, low-reflective, or anti-reflective layers may be incorporated into the mode matching optics 440 to reduce the effects of external light introduced into the emitter system 400.

[0029] Referring back to FIG. 4, it should be noted that various variations of the emitter 410, the LED cavity 424, the etendue gate 430, and the mode matching optics 440 may be envisioned. For example, the emitter 410 may include a single emitter (e.g., a single light emitting diode), a group of two or more emitters of the same color, or a group of two or more emitters of different colors. As an example, the emitter 410 may include a combination of a red LED, a green LED, and a blue LED in a single LED cavity 424. Alternatively, the emitter 410 may include a combination of two LEDs that emit the same color, e.g., two red LEDs. The LED cavity 424 may include one or more surfaces that include a high reflectivity coating, such as, for example, a silver or aluminum reflector. The high reflectivity coating material may be selected to provide low angular dependence of the reflectivity characteristics, such that light over a range of angles of incidence is efficiently reflected within the LED cavity 424.

[0030] Additionally, the etendue gate 430 may include a single aperture, as shown in FIG. 4, or may include multiple apertures. Additionally, the etendue gate 430 may incorporate optical components such as wavelength selective filters, polarizers, grating structures, and / or refractive elements. The polarizer may transmit light of a first polarization state while reflecting light of a second, orthogonal polarization state back into the LED cavity 424. In this manner, a portion of the reflected light may be recycled within the LED cavity 424, such that a portion of the reflected recycled light may be converted to a first polarization and transmitted through the polarizer and out of the LED cavity 424.

[0031] In an embodiment, a polarizer or reflective surface within the LED cavity 424 may include features to randomize the polarization state of light transmitted or reflected therefrom. Alternatively, multiple etendue gates 430 may be coupled to the LED cavity 424. In an embodiment, a first etendue gate includes a polarizer for transmitting light of a first polarization state, while a second etendue gate includes a polarizer for transmitting light of an orthogonal second polarization state, such that the first etendue gate directs light toward a first location and the second etendue gate directs light toward a different second location.

[0032] 4 shows the etendu gate 430 aligned with the emitter 410, the etendu gate 430 may be offset from the centerline (e.g., optical axis) of the emitter 410 to adjust the amount and directionality of light transmitted through the etendu gate 430 to accommodate the requirements of the mode-matching optics 440. Additionally, the distance of the etendu gate 430 relative to the emitter 410 and the mode-matching optics 440 may be adjusted according to the desired light output.

[0033] Additionally, the mode-matching optics 440 may include at least one of the following types of optical components: refractive, filtering, polarizing, diffractive, and reflective. The mode-matching optics may form an imaging or non-imaging optical system. For example, the mode-matching optics 440 may include one or more of a spherical, cylindrical, and asymmetric optical component. The mode-matching optics 440 may further include one or more diffraction gratings, filters, and / or polarizers. The mode-matching optics 440 may be tailored to the needs of a particular application to provide an optical output with specific beam parameters, such as beam shape, telecentricity, directionality, etc., to optimize coupling of the optical output with downstream optics, such as a projector and / or a waveguide.

[0034] For example, if red, green, and blue LEDs are included as emitters 410, the etendue gate 430 and mode matching optics 440 may be positioned relative to the LEDs such that the red, green, and blue light generated by the LEDs may be directed in different directions according to color, and may exhibit wavelength-dependent refractive behavior. Furthermore, one or more reflective surfaces may be incorporated around the emitter 410, for example as surfaces at least partially defining the cavity 424, such that light emitted from the emitter 410 anywhere around the emitter 410 may be trapped and reflected into the LED cavity 424. In this way, the light distribution from the emitter 410 may be optimized for coupling into, for example, an input coupling grating (ICG), which may exhibit incident angle-dependent light coupling behavior.

[0035] The aperture shape of the etendu gate 430 and / or the mode-matching optics 440 may be circular, cylindrical, elliptical, rectangular, or square. Additionally, any of the surfaces of the emitter 410, the LED cavity 424, the etendu gate 430, and the mode-matching optics 440 may include one or more of a variety of features, such as a diffraction grating, a texture, an anti-reflective coating, a low index layer, a light absorbing material, an insulating material, a conductive material, a semiconductor material, an alloy, etc.

[0036] In general, the positions and shapes of the emitter 410, the LED cavity 424, the etendue gate 430, and the mode matching optics 440 can be decoupled from one another, thus allowing flexibility in the design of the various components of the positions and shapes, and can be adjusted on an emitter-by-emitter or pixel-by-pixel basis. The shape and form of each component shown in FIG. 4 can be formed, for example, by optical lithography, wet or dry etching procedures, nanoimprinting, and other known processing techniques. In this manner, the shape and form of each component shown in FIG. 4 can be varied throughout the array of LED emitter systems 400. Additionally, one or more color converters or other components for wavelength-dependent filtering, color conversion, attenuation, color tuning, phase correction, and / or wavefront shaping can be incorporated into one or more of the emitter 410, the LED cavity 424, the etendue gate 430, and the mode matching optics 440.

[0037] 5, the etendue gate 430 and mode matching optics 440 in the emitter system 500 may be replaced with a textured surface 530 to diffuse the light emitted from the emitter 410. In this case, the surface 422 of the LED cavity may be configured to efficiently direct the light emitted from the emitter 410 towards the textured surface 530 to provide a light output suitable for use in applications that do not require a collimated light output.

[0038] In certain cases, the LED cavity can be reduced or eliminated by appropriately designing the mode-matching optics 440. For example, as shown in FIG. 6, an emitter system 600 can include an emitter 410 located at the apex or focal plane of a surface 622 that defines a truncated compound parabolic curve (CPC), where the surface 622 functions as the mode-matching optics 440. For the emitter system 600, the surface 622 can provide sufficient mode-matching and shaped light output for a particular application. The surface 622 can be or include a concave paraboloid. The surface 622 can be a reflective surface, such as a reflective surface formed from a metal or dielectric coating. The surface 622 can be a surface of a substrate 620.

[0039] 7, an aspheric lens 740 may be used as the mode matching optic 440 formed adjacent to the emitter 410. The aspheric lens 740 may include sidewalls 742 that are formed to provide a light output of a suitable shape for a particular application with only the cavity-free aspheric lens 740 by appropriate design of the shaped sidewalls 742. In an embodiment, the sidewalls 742 are adjacent to a surface of the substrate 720. Each substrate 620, 720 is an example of a substrate 420.

[0040] 8 illustrates a cross-sectional view of an emitter array system 800 including light extraction features according to one embodiment. The emitter array system 800 includes an LED substrate 805 that supports and / or at least partially contains a plurality of emitters 810. The emitters 810 may be arranged in a two-dimensional array. Each emitter 810 is an example of an emitter 410 and is at least partially surrounded by a concave surface of the LED substrate 805.

[0041] Emitter 810 includes at least one each of emitters 810A, 810B, and 810C. In an embodiment, emitters 810A, 810B, and 810C are configured to emit light in a different respective one of three wavelength ranges. In an embodiment, the ranges correspond to the red, green, and blue regions of the electromagnetic spectrum. In another configuration, emitters 810A, 810B, and / or 810C may be configured to emit light in the same wavelength range.

[0042] In one example, each one of the emitters 810A, 810B, and 810C is surrounded by a reflective surface 815 such that light emitted by that emitter is directed downward in FIG. 8. The reflective surface 815 may be a coating formed from a metal (e.g., aluminum, gold, silver), a dielectric, a multi-layer film stack of dielectric materials, or any combination thereof. If the reflective surface 815 is a coating, the coating may be on a concave surface of the LED substrate 805.

[0043] The emitter array system 800 further includes a substrate 820 having a cavity defined by a surface 822. The substrate 820 may be a portion of the substrate 805. Examples of the surface 822 include the surface 422 and the surface 622. Examples of the substrate 820 include the substrates 420, 620, and 720.

[0044] Each respective LED cavity 824A, 824B, 824C is adjacent to an emitter 810A, 810B, 810C, respectively. The substrate 820 may be formed of a semiconductor (such as GaN) or other material (such as an insulator or transparent conductive oxide) suitable for light transmission of the desired wavelengths. The reflective surface 822 may have a coating thereon which may be formed of a metal (e.g., aluminum, gold, silver), a dielectric, a multi-layer film stack of dielectric materials, or any combination thereof.

[0045] The reflective surfaces 822 confine and / or shape the light emitted from the emitters 810A, 810B, 810C, respectively. In an embodiment, each surface 822 extends between the top and bottom surfaces of the substrate 820 such that the surface 822 defines an aperture through the substrate 820. For example, the LED cavity 824A may be defined by a cavity geometry that is optimized to couple the light emitted by the emitter 810A into the aperture 830A, the LED cavity 824B may be optimized to couple the light emitted by the emitter 810B into the aperture 830B, and the LED cavity 824C may be formed to best match the light emitted by the emitter 810C to be coupled into the aperture 830C. In another example, two or more of the LED cavities 824A, 824B, 824C may be identical to one another. Similarly, opening 830A may be different from openings 830B and / or 830C, or the dimensions of openings 830A, 830B, 830C may be the same.

[0046] The apertures 830A, 830B, 830C may be formed conjugate with the plane of an input coupling grating (ICG), such as one that serves as the input port of a waveguide for near-eye display glasses. Other types of throughput-limiting aperture configurations may be implemented according to the requirements of mode-coupling optics or other downstream optics from the aperture. Additionally, optionally, at least one of the apertures 830A, 830B, 830C may include additional optical properties, such as angle, wavelength, and / or polarization filtering capabilities.

[0047] Light emitting from LED cavities 824A, 824B, 824C through apertures 830A, 830B, 830C, respectively, is directed through lenslets 840 in the example shown in Figure 8. Each one of the lenslets 840 is an example of the mode-matching optics 440 of Figure 4. In the example shown in Figure 8, each lenslet 840 is configured to direct light from multiple emitters 810A, 810B, 810C. Each one of the lenslets 840 may be formed directly on a backplane, for example, or may be part of a lenslet array that is formed separately and attached to the backplane after formation of the apertures and absorber coating.

[0048] The emitter array system 800 may include a baffle absorber 845 that separates adjacent lenslets 840. For example, the light baffle absorber 845 may be configured to reduce crosstalk between adjacent lenslets 840. Additionally, the areas between the apertures 830A, 830B, 830C may be covered by an absorbing layer 847 to further reduce stray light passing through the lenslets 840.

[0049] In an embodiment, line 870 represents a boundary above which formers of emitters 810A, 810B, 810C, reflective surface 815, portions of LED cavities 824A, 824B, 824C, and reflective surface 822 may be formed as part of the micro-LED fabrication (as indicated by arrow 872). Below line 870 (as indicated by arrow 872), various components may be formed during processing performed after micro-LED fabrication is completed.

[0050] 9 illustrates an emitter array system 900 according to one embodiment. The emitter array system 900 includes the same micro LED manufacturing side components as the emitter array system 800 of FIG. 8. However, each one of the apertures 830A, 830B, 830C is coupled with its own lenslet 940A, 940B, 940C, respectively. Adjacent lenslets 940A, 940B, 940C may be separated by a light baffle absorber 945, and the area between the apertures 830A, 830B, 830C may be covered by an absorber layer 947. In this configuration, each one of the lenslets 940A, 940B, 940C may be configured to couple with a particular wavelength and other optical characteristics of the light emitted by a corresponding one of the emitters 810A, 810B, 810C.

[0051] FIG. 10 illustrates an emitter array system 1000 according to an embodiment. The emitter array system 1000 includes an LED substrate 1005 supporting emitters 810A, 810B, 810C having a reflective surface 815 as shown in FIG. 8. In contrast to the emitter array system 800 of FIG. 8, the emitter array system 1000 includes one LED cavity 1024 for the group of emitters 810A, 810B, 810C. The emitter array system 1000 further includes a substrate 1020 having a surface 1022 that defines the cavity 1024. The substrate 1020 may be part of the substrate 1005. The geometry of the LED cavity 1024 and the properties of the substrate 1020 may be adjusted for optimal coupling of light emitted from the emitters 810A, 810B, 810C towards the aperture 1030 and into the lenslet 1040. Lenslet 1040 is an example of lenslet 840 in Figure 8. Adjacent lenslets 1040 may be separated by light baffle absorber 1045, and the areas between the apertures 1030 may be coated with absorber material 1047. Substrates 1005 and 1020 are examples of substrates 805 and 820, respectively.

[0052] 11 illustrates an exemplary process 1100 for forming the previously disclosed emitter array system according to one embodiment. The process 1100 includes forming an emitter array on an emitter substrate 1110. Referring to FIG. 8, forming emitters 810A, 810B, 810C supported on or in a substrate 805 1110 may include at least one of (i) forming a reflective surface 815 surrounding the emitters 810A, 810B, 810C, (ii) forming the micro LED side of the LED cavities 824A, 824B, 824C, and (iii) forming a portion of the reflective surface 822.

[0053] Process 1100 proceeds to step 1120 to attach the emitter array to a backplane, followed by step 1130 to form the remainder of the LED cavities and openings. For example, after the emitter array is attached to the backplane, the emitter substrate supporting the emitter array may be removed. Finally, process 1100 proceeds to step 1140 to attach lenslets to form the structures shown in, for example, Figures 8-10.

[0054] Further examples of embodiments of light extraction features are shown in FIGS. 12 shows an emitter system 1200 including an emitter 810 having an ohmic contact 1212. Light emitted from the emitter 810 is directed into an LED cavity 1224. The emitter system includes a substrate 1205, which is an example of a substrate 805. The substrate 1205 includes a sidewall 1225. The cavity 1224 is defined by the respective surfaces of the sidewall 1225, the baffle 1247, and the top reflector 1227. One or both of the baffle 1247 and the reflector 1227 may be part of the substrate 1205. The sidewall 1225 may include one or more sidewalls or may be a layer deposited on the substrate 1205.

[0055] A portion of the light from the LED cavity 1224 is transmitted through the etendue gate 1230 and through the mode matching optics 1240 (shown here as a refractive element). The etendue gate 1230 and the optics 1240 are examples of the etendue gate 430 and the optics 440, respectively. The optical properties (e.g., shape, refractive index, beam shaping / steering) of the mode matching optics 1240 are tuned to optimize the coupling of the light from the emitter 810 with downstream optics such as a projector or a waveguide. The sidewalls 1225 confine the light emitted from the emitter 810 within the LED cavity 1224. In an embodiment, the top reflector 1227 covers the gap around the emitter 810 and the reflective sidewalls 1225 to prevent light from leaking through the gap. The top reflector 1227 can be used as an electrical contact.

[0056] 12, an absorber 1245 surrounds the mode-matching optic 1240 to absorb any stray light that is not directed out of the mode-matching optic 1240. Additionally, the baffle 1247 that serves to define the boundary of the etendue gate 1230 may also exhibit light absorbing properties that reduce stray light re-entering the LED cavity 1224 from the mode-matching optic 1240.

[0057] As shown in FIG. 12, a low index (low-n) layer 1250 surrounds the etendue gate 1230 and the baffle 1247. The index of refraction of the low-n layer 1250 may be lower than the material filling the LED cavity 1224. As an example, if the LED cavity 1224 is filled with n-doped gallium nitride (n-GaN) having an average index of refraction n=2.4, the low-n layer 1250 may be a material with an average index of refraction lower than 2.4. Examples include materials with an average index of refraction n=1.4, such as polymers. Similarly, the mode-matching optics 1240 may be formed from a high index polymer exhibiting, for example, n=1.7, such that there is an index discontinuity between the low-n layer 1250 and the mode-matching optics 1240.

[0058] Thus, there are multiple interfaces encountered by the light emitted from the emitter 810, as indicated by the circled numbers in FIG. 12. At the (1)-(2) interface, the light from the LED cavity 1224 that encounters the low-n layer 1250 is largely reflected back into the LED cavity 1224 due to the refractive index discontinuity at the interface. Similarly, at the (3)-(4) interface, the light is refracted as indicated by arrow 1280. Finally, as the light exits the mode-matching optics 1240, it is shaped and directed towards the external optics. Thus, the inclusion of the low-n layer 1250 helps to further tune the light confinement and efficient extraction of the light emitted by the emitter 810.

[0059] Although a single emitter system 1200 is shown in Figure 12, multiple emitter systems 1200 may be arranged in an array. The emitter systems in the array may be identical, or emitter systems having different emission characteristics may be included in the array.

[0060] 13 illustrates another example of a light extraction configuration according to an embodiment of the present disclosure. As shown in FIG. 13, the emitter system 1300 includes a light emitter 810 having an ohmic contact 1212. Light emitted from the emitter 810 is directed into an LED cavity 1324. The emitter system 1300 includes a substrate 1305, which is an example of the substrate 805. The substrate 1305 includes a sidewall 1325. The cavity 1324 is at least partially defined by respective surfaces of the sidewall 1325 and a baffle 1347. The baffle 1347 may be part of the substrate 1305. The sidewall 1325 may include one or more sidewalls or may be a layer deposited on the substrate 1305.

[0061] A portion of the light from the LED cavity 1324 is transmitted through the etendue gate 1330 and through the mode-matching optics 1340. The etendue gate 1330 is an example of the etendue gate 430. Again, the optical properties of the mode-matching optics 1340 are tailored to optimize the coupling of the light from the emitter 810 with downstream optics such as a projector or a waveguide. Reflective sidewalls 1325 confine the light emitted from the emitter 810 within the LED cavity 1324. An absorber 1345 surrounds the mode-matching optics 1340 to absorb any stray light that is not directed out of the mode-matching optics 1340. Additionally, the baffle 1347 that helps define the boundaries of the etendue gate 1330 may exhibit light absorbing properties that reduce stray light re-entering the LED cavity 1324 from the mode-matching optics 1340. In an embodiment, the etendue gate is an opening through the baffle 1347.

[0062] Emitter system 1300 includes a low-n layer 1350 similar to low index layer 1250 of emitter system 1200. Portions of the low-n layer are above and below baffle 1347, and within etendue gate 1330. The low-n layer 1350 also extends along reflective sidewalls 1325 to further enhance the light confinement characteristics of the LED cavity 1324. Additionally, emitter system 1300 may include an anti-reflective layer 1390 at the interface between the high index material forming the LED cavity 1324 and the low-n layer 1350.

[0063] In an embodiment, the emitter system 1300 includes a second anti-reflective layer 1392 at the interface between the low-n layer 1350 and the mode-matching optics 1340. Additionally, a third anti-reflective layer (not shown) may be included at the interface between the mode-matching optics 1340 and any downstream optics (not shown). The anti-reflective layer may function to enhance the coupling of light emitted from the emitter 810 out of the LED cavity 1324 and into the mode-matching optics 1340.

[0064] 14 and 15 respectively show partial cross-sectional and partial top views of an emitter system 1400 with light extraction and shared cathode features according to an embodiment of the disclosure. By extending the reflective light confinement layer around the LED cavity and between the emitter systems, the reflective layer itself can be used as a shared cathode for electronically addressing the light emitters. In particular, the emitter system 1400 includes multiple emitters 810, each of which is individually addressable via ohmic contacts 1212. As with the emitter systems described above, each emitter 810 is coupled to an LED cavity 1420 surrounded by a reflective layer 1425. The reflective layer 1425 is an example of a sidewall 1225, 1325, which may be formed, for example, from a reflective metallic material. Light from the emitter 810 is coupled through the LED cavity 1420 to a mode-coupling optic 1440. The mode-coupling optic 1440 may be an example of a mode-matching optic 440. The emitter system 1400 can include a substrate, such as substrate 1205, 1305, in which case the reflective layer 1425 can be a layer deposited on the substrate.

[0065] In an embodiment, low-n layer 1430 may be incorporated into the LED cavity 1420, the mode-coupling optics 1440, or anywhere in between to help improve light confinement efficiency within the LED cavity 1420 and from the mode-coupling optics 1440. Low-n layer 1450 may also extend between emitters 810 to act as an insulating layer to electrically isolate the emitters 810 from one another.

[0066] 14 and 15 , the reflective layer 1425 may extend between the emitters 810 so that it can be used as a shared cathode for the emitters 810 in the emitter system 1400. Individual addressing of each emitter 810 may be achieved by bonding via an associated ohmic contact 1212.

[0067] When silver is incorporated into the aforementioned reflective layers (e.g., reflective surfaces 1225, 1325, 1425), a known problem is the migration of silver into undesired areas of the emitter system, which can result in electrical shorting of the emitter. The configuration of the low-n layers 1350, 1430 of Figures 13 and 14 can help mitigate the migration of silver into the LED cavity. Additionally, the aforementioned reflective surfaces 1225, 1325, 1425 can also be further encapsulated in a coating to preserve the reflective properties of the reflector while mitigating problems associated with electric field induced silver migration.

[0068] Figures 16-19 show examples of light confinement features for confining light emitted by an emitter according to aspects of the present disclosure. It is noted that Figures 16-19 only show structures surrounding the emitter portion of the emitter system, i.e., the embodiments shown in Figures 16-19 may further incorporate light extraction structures such as those shown in Figures 4-15 above.

[0069] Referring first to Figure 16, this figure shows a portion of an emitter array 1600 incorporating a light confinement mechanism. The emitter array 1600 includes a number of emitters 810, each with an ohmic contact 1212 on top. For the most part, light emitted from the emitters 810 is directed downwards (i.e., towards the bottom edge of the page). However, a small portion of the light emission escapes around each emitter 810. The ohmic contacts 1212 block most of the light emission upwards (i.e., towards the top edge of the page), but light emission can escape out the sides of the emitter 810.

[0070] To address light leakage upwards and laterally, each emitter 810 can be surrounded by a reflective material to redirect light leakage downwards, e.g., to the light extraction structures described above with respect to Figures 4-15. In the example shown in Figure 16, the emitters 810 are covered by a passivation or insulating layer 1614. Using known techniques such as dry etching, wet etching, and mask lithography, a reflective structure 1618 is deposited laterally and upwards towards the ohmic contacts of each emitter 810. The passivation layer 1614 separates the reflective structure 1618 from contact with the emitters 810 and the ohmic contacts 1612. A further passivation or insulating layer may be deposited over the reflective structure 1618, after which further "wing" structures 1620 may be formed to provide further confinement of light escaping around the ohmic contacts 1612. Electrical contact may be made directly to the ohmic contact 1212 (shown as electrical contact 1616), as shown in the emitter structure on the right side of Figure 16, or electrical contact may be made through a wing structure 1620, as shown in the emitter structure on the left side. Any one of the embodiments of the emitter systems described in Figures 8-15 may include at least one of an insulating layer 1614, a reflective structure 1618, an electrical contact 1616, and a wing structure 1620.

[0071] Even if direct contact is made to the ohmic contact 1212, Figure 17 shows another embodiment in which a wing structure is formed in direct electrical contact with the ohmic contact. For example, after the passivation layer 1614 is deposited over the emitter 810 and the ohmic contact 1212, a reflective structure 1730 can be formed on the side of the emitter 810. A further passivation layer 1732 is deposited over the reflective structure 1730. Then, a further reflective structure 1740 is deposited thereon, also as shown in Figure 17.

[0072] The ohmic contact 1212 can then be accessed through the passivation layer 1614, the further passivation layer 1732, and the further reflective structure 1740, allowing the electrical contact 1616 to be connected to the ohmic contact 1212 while maintaining electrical isolation between adjacent emitters 810. Any one of the embodiments of the emitter systems described in Figures 8-16 may include at least one of the reflective structure 1730, the passivation layer 1732, and the reflective structure 1740.

[0073] FIG. 18 shows another configuration in which thin contacts are used to electrically address the ohmic contacts 1212. As shown in FIG. 18, a passivation layer 1614 covers the emitter 810 and the ohmic contacts 1212, and the large reflective structures 1840 are deposited thereon such that there is an overlap 1842 between the ohmic contacts 1212 and the large reflective structures 1840 while maintaining a space between the large reflective structures 1840 to allow electrical access to the ohmic contacts 1212 using thin bonding wires 1815 attached to thicker bonding wires 1816. In this way, optical confinement around the emitter 810 can be established in one pass of reflective layer deposition without creating a short circuit between the emitter, the large reflective layer, and the thin bonding wires 1815. Any one of the embodiments of the emitter systems shown in FIG. 8-FIG. 16 may include at least one of the reflective structures 1830, the overlap 1842, the thin bonding wires 815, and the thicker bonding wires 1816.

[0074] Yet another alternative structure for light containment is shown in FIG. 19, which illustrates a portion of an array of emitter systems. As shown in FIG. 19, emitter system 1900 includes at least one emitter 810. A passivation layer 1922 is formed over emitter 810 to provide electrical isolation. Optionally, a reflective structure (not shown) similar to those shown in FIGS. 16-18 may be formed over passivation layer 1922. Emitter system 1900 includes a dielectric Bragg reflector 1930 over emitter 810 to provide a reflective surface for containing light leakage from emitter 810.

[0075] The dielectric Bragg reflector 1930 includes multiple layers of dielectric thin films exhibiting alternating high and low refractive indices. In an embodiment, as shown in FIG. 19, the dielectric Bragg reflector 1930 is in direct contact with the emitter 810 through an opening in the passivation layer 1922. In an embodiment, the passivation layer 1922 can be incorporated into the design of the dielectric Bragg reflector 1930 such that the refractive index of the passivation layer 1922 contributes towards the overall reflectivity of the Bragg reflector 1930, and an opening in the passivation layer 1922 is not required. Finally, an ohmic contact 1212 can be placed on top of the dielectric Bragg reflector 1930 to electronically address the emitter 810.

[0076] Any one of the embodiments of the emitter systems described in Figures 8-16 may include at least one of a passivation layer 1922, a dielectric Bragg reflector 1930, and an ohmic contact 1212 thereon.

[0077] 20-26 illustrate an exemplary process flow for forming an emitter having a structure for light extraction according to an embodiment of the present disclosure. As shown in FIG. 20, an emitter array structure 2000 includes an emitter 810 formed on a planar surface of a semiconductor substrate 2014. An ohmic contact 1212 is on the emitter 810. The semiconductor substrate 2014 is an example of a substrate 805. In FIG. 21, the semiconductor substrate 2014 is modified to result in a semiconductor substrate 2114 that includes a cutout 2120 formed in the underside of the semiconductor substrate. In FIG. 22, a low-n layer 2230 (as an example, n<2.4) is conformally deposited on the underside of the semiconductor substrate 2114.

[0078] 23, a via is formed in the semiconductor substrate 2114 through the cutout 2120 and the low-n layer 2230 to provide a semiconductor substrate 2314. Additionally, a reflective material 2340 is deposited in the via to form the basis of the LED cavity as previously described.

[0079] In Figure 24, another second layer of low-n material 2450 is deposited on the underside of the semiconductor substrate 2314. In Figure 25, a polymer material 2560 is deposited to form the basis of the mode-matching optics as previously described. In Figure 26, vias are formed in the polymer material 2560 and absorbing structures are formed therein to form the mode-matching optics as previously described.

[0080] 27-37 illustrate possible variations in emitters and emitter arrays having light extraction features according to embodiments of the present disclosure.

[0081] Fig. 27 shows a variation of the emitter system 400 of Fig. 4. As shown in Fig. 27, the emitter system 2700 includes three different emitters 2710A, 2710B, 2710C, each emitter emitting light at a different wavelength (e.g., emitter 2710A emits in the red wavelength range, emitter 2710B emits in the green wavelength range, and emitter 2710C emits in the blue wavelength range) arranged in a single LED cavity 2720. A single etendue gate 2730 connects the LED cavity 2720 with a mode matching optics 2740 having an exit pupil 2750. This embodiment corresponds, for example, to one RGB pixel being integrated into one light extraction structure.

[0082] As another example, Fig. 28 shows a pair of emitters located in each light extraction structure. As shown in Fig. 28, the emitter system 2800 includes a first emitter 2810A and a second emitter 2810B housed in a first LED cavity 2820A and connected with a first etendue gate 2830A, a mode matching optics 2840A, and an exit pupil 2850A. The emitter system 2800 further includes another second emitter 2810B and a third emitter 2810C housed in a second LED cavity 2820B and connected with a second etendue gate 2830B, a second mode matching optics 2840B, and a second exit pupil 2850B. As an example, the configuration of the first etendue gate 2830A, the mode matching optics 2840A, and the exit pupil 2850A may be selected to provide optimal light confinement and extraction for a particular combination of wavelengths emitted by the first emitter 2810A and the second emitter 2810B, while the second etendue gate 2830B, the second mode matching optics 2840B, and the second exit pupil 2850B are optimized for the wavelengths provided by the combination of the second emitter 2810B and the third emitter 2810C.

[0083] 29 shows an emitter system 2900 including a pair of first emitters 2910A housed by a first LED cavity 2920A and coupled with a first etendue gate 2930A, mode matching optics 2940A, and an exit pupil 2950A. The emitter system 2900 further includes a second emitter 2910B and a third emitter 2910C housed within a second LED cavity 2920B and coupled with a second etendue gate 2930B, second mode matching optics 2940B, and a second exit pupil 2950B. Such a configuration may be useful, for example, in situations where the light emission efficiency of the first emitter 2910A is significantly lower than the light emission efficiency of emitters 2910B, 2910C, such that optimization of the light extraction efficiency of the first emitter 2910A pair is necessary to produce a desired light color gamut from the combination of three different emitters.

[0084] Alternatively, Fig. 30 shows a variation of the emitter system 2700 of Fig. 27, this time including three different etendue gates. As shown in Fig. 30, the emitter system 3000 includes three different emitters 3010A, 3010B, 3010C, each emitting light at a different wavelength (e.g., emitter 3010A emits in the red wavelength range, emitter 3010B emits in the green wavelength range, and emitter 3010C emits in the blue wavelength range) and disposed within a single LED cavity 3020. Three separate etendue gates 3030A, 3030B, 3030C connect the LED cavity 3020 with a mode-matching optics 3040 having an exit pupil 3050. This configuration may be effective, for example, when it is desirable to separate the directionality of the optical radiation from each of the emitters 3010A, 3010B, 3010C at the exit pupil 3050 by spatially filtering the optical radiation that may pass through the three etendue gates. As an example, the etendue gate 3030A may be optimized to accept light of the wavelengths emitted by the emitter 3010A, the etendue gate 3030B may be optimized to accept light of the wavelengths emitted by the emitter 3010B, and the etendue gate 3030C may be optimized to accept light of the wavelengths emitted by the emitter 3010C, such that the direction of the light rays transmitted through the three etendue gates are of a particular wavelength and are generally directed in a known direction (e.g., directly down in the figure).

[0085] Figure 31 shows another variation including three different emitters, a single LED cavity, a single etendue gate, and three different output pupils. As shown in Figure 31, the emitter system 3100 includes three different emitters 3110A, 3110B, 3110C, each emitter emitting light at a different wavelength (e.g., emitter 3110A emits in the red wavelength range, emitter 3110B emits in the green wavelength range, and emitter 3110C emits in the blue wavelength range) and is disposed within a single LED cavity 3120. The light emitted by the emitter 3110 passes through a single etendue gate 3130 into a single set of mode-matching optics and is then directed to three different output pupils 3150A, 3150B, 3150C.

[0086] In contrast, Figure 32 essentially shows a combination of three emitter systems 400, each optimized for a particular light emission wavelength. As shown in Figure 32, the emitter system 3200 includes a first emitter 3210A housed within a first LED cavity 3220A and coupled with a first etendue gate 3230A, a first mode matching optics 3240A, and a first exit pupil 3250A. Each of the first LED cavity 3220A, the first etendue gate 3230A, the first mode matching optics 3240A, and the first exit pupil 3250A is optimized for confinement and extraction of light in the red wavelength range. Similarly, the emitter system 3200 further includes a second emitter 3210B housed within a second LED cavity 3220B and coupled with a second etendue gate 3230B, a second mode matching optic 3240B, and a second exit pupil 3250B. Additionally, the emitter system 3200 includes a third emitter 3210C housed within a third LED cavity 3220C and coupled with a third etendue gate 3230C, a third mode matching optic 3240C, and a third exit pupil 3250C. The second LED cavity 3220B, the second etendue gate 3230B, the second mode matching optics 3240B, and the second exit pupil 3250B are optimized to operate at green wavelengths, while the third LED cavity 3220C, the third etendue gate 3230C, the third mode matching optics 3240C, and the third exit pupil 3250C are optimized to confine and direct blue wavelengths.

[0087] Yet another variation is shown in Figure 33. Figure 33 shows an emitter system 3300 that includes an emitter 3310 housed within an LED cavity 3320. Each of the emitters 2710, 2810, 2910, 3010, 3110, 3210, 3310 is an example of an emitter 810.

[0088] The first etendue gate 3330A and the second etendue gate 3330B may be configured to transmit different portions of the light emitted by the emitter 3310 such that the light transmitted through the first and second etendue gates exhibits different characteristics (e.g., orthogonal polarization states, or low-pass and high-pass filtering). The transmitted light is then directed through the mode matching optics 3340 and the exit pupil 3350.

[0089] The various etendue gates and exit pupils shown in Figures 8-10, 12, 13, and 27-37 illustrate some of the various possible shapes of the apertures presented by these components. For example, as shown in Figure 34, each etendue gate or exit pupil may be circular. Alternatively, as shown in Figure 35, each etendue gate or exit pupil may be elliptical. Similarly, as shown in Figures 36 or 37, each etendue gate or exit pupil may be rectangular or hexagonal. Other shapes for the etendue gates and exit pupils are possible, alone or in combination, such as in the above cases where multiple etendue gates and / or exit pupils are combined in a single emitter system.

[0090] The following description is intended to cover the general and specific features described herein. In particular, the following embodiments, and any combination of such embodiments, are contemplated.

[0091] 1. Each cavity disclosed herein may contain one or more emitters therein. In such cases, adjacent cavities may or may not be completely optically isolated from each other. For example, some degree of optical interaction between adjacent cavities may be desirable for anti-aliasing or brightness / efficiency, depending on the requirements of a given application.

[0092] 2. Each cavity disclosed herein may include one or more exit openings. 3. Each lenslet disclosed herein may be configured to direct light from one or more cavities.

[0093] 4. The forward facing exterior surface (i.e., the surface facing the mode matching optics) of any etendugate disclosed herein may include at least one of an absorptive, low reflectance, non-reflective, or other anti-reflective coating to improve display contrast when ambient light strikes the emitter. Such mechanisms to control reflections from the etendugate can be included in emitter systems with or without subsequent mode matching optics or lenslets.

[0094] 5. Any of the etendue gates disclosed herein can include a polarizer so that the emitter system provides a polarized output. In one example, the polarizer is configured to transmit light of a first polarization state while reflecting a second polarization back into the cavity, which can provide a polarized output with greater efficiency than an absorptive polarizer.

[0095] Combination of features The features described above and in the claims below can be combined in various ways without departing from the scope of the invention. The following list illustrates some non-limiting combinations that are possible.

[0096] (A1) An emitter system assembly for providing a light output to a projector includes an emitter providing light radiation, a cavity at least partially surrounding the emitter, an aperture configured to transmit at least a portion of the light radiation from the emitter, and a lenslet in optical communication with the aperture, the cavity including a reflector for reflecting the light radiation within the cavity towards the aperture, the cavity, the aperture, and the lenslet configured to cooperate to provide a light output having optical characteristics suitable for coupling to a projector.

[0097] In the (A2)(A1) embodiment, the cavity, aperture, and lenslets are configured to provide a light output having at least one of a predetermined output direction and solid angle.

[0098] (A3) Any one of embodiments (A1) or (A2) further includes a second emitter for providing a second light emission.

[0099] (A4) In any one of embodiments (A1)-(A3), the emitter provides optical radiation in a first wavelength range and the second emitter provides a second optical radiation in a second wavelength range, the second wavelength range being different from the first wavelength range.

[0100] (A5) In any one of embodiments (A1)-(A4), the cavity at least partially surrounds both the emitter and the second emitter.

[0101] (A6) In any one of embodiments (A1)-(A5), the aperture is configured to transmit at least a portion of both the optical radiation and the second optical radiation.

[0102] (A7) Any one of embodiments (A1)-(A6) further includes a second cavity at least partially surrounding the second emitter, a second aperture configured to transmit at least a portion of the optical emission from the emitter, and a second lenslet in optical communication with the second aperture.

[0103] (A8) Any one of the embodiments (A1)-(A7) further includes a light baffle absorber to at least partially prevent crosstalk between the light output and the second light output.

[0104] (A9) Any one of the embodiments (A1)-(A8) further includes a third emitter for providing a third light emission in a third wavelength range, the third wavelength range being different from the first and second wavelength ranges.

[0105] (A10) In any one of embodiments (A1)-(A9), the lenslets are formed from a low refractive index material.

[0106] (A11) Any one of the embodiments (A1)-(A10) further comprises an anti-reflective layer on the lenslets.

[0107] (A12) Any one of the embodiments (A1)-(A11) further includes an optical confinement structure around the emitter.

[0108] (A13) In any one of embodiments (A1)-(A12), the light confinement structure includes at least one of a reflective layer and a dielectric Bragg reflector.

[0109] (B1) An emitter system assembly for providing a light output to a projector includes a first emitter providing a first light emission, a second emitter providing a second light emission, a first cavity at least partially surrounding the first emitter, a second cavity at least partially surrounding the second emitter, a first opening configured to transmit at least a portion of the first light emission from the first emitter, a second opening configured to transmit at least a portion of the second light emission from the second emitter, and a first and second apertures configured to transmit at least a portion of the first light emission from the first emitter, a second aperture configured to transmit at least a portion of the second light emission from the second emitter, and a second aperture configured to transmit at least a portion of the first and second apertures. and a lenslet in optical communication with the aperture, the first cavity including a first reflector for reflecting a first optical radiation within the first cavity towards the first aperture, and the second cavity including a second reflector for reflecting a second optical radiation within the second cavity towards the second aperture, the first cavity, the first aperture, the second cavity, the second aperture, and the lenslet are configured to cooperate to provide the first and second optical radiation to contribute to a light output having optical characteristics suitable for coupling into a projector.

[0110] (B2) In embodiment (B1), the first cavity, the first aperture, the second cavity, the second aperture, and the lenslet are configured to provide a light output having at least one of a predetermined output direction and solid angle.

[0111] (B3) Any one of the embodiments (B1) or (B2) further comprises a light baffle absorber to prevent crosstalk between the first and second cavities.

[0112] (C1) An emitter system assembly for providing a light output to a projector includes a first emitter providing a first light radiation, a second emitter providing a second light radiation, a cavity at least partially surrounding the first and second emitters, an aperture configured to transmit at least a portion of the first and second light radiation from the first and second emitters, and a lenslet in optical communication with the aperture, the cavity including a reflector for reflecting the first and second light radiation within the cavity towards the aperture, the cavity, the aperture, and the lenslet configured to cooperate to provide a light output having optical properties suitable for coupling into a projector.

[0113] (C2) In the embodiment of (C1), the cavity, aperture, and lenslets are configured to provide a light output having at least one of a predetermined output direction and solid angle.

[0114] (D1) A method for forming an emitter system assembly includes forming an emitter array on an emitter substrate, attaching the emitter substrate to a backplane, forming an array of cavities and an array of apertures aligned with the emitter array, and attaching a lenslet array aligned with the array of apertures.

[0115] (D2) The method (D1) further includes removing the emitter substrate while leaving the emitter array attached to the backplane.

[0116] Thus, although the present disclosure has been provided according to the illustrated implementations, it will be readily apparent to those skilled in the art that there may be variations in the embodiments, and these variations are within the scope of the present disclosure. Accordingly, many modifications may be made by those skilled in the art without departing from the scope of the appended claims.

Claims

1. 1. An emitter system assembly for providing a light output to a projector, comprising: a first emitter providing a first light emission; a first cavity at least partially surrounding the first emitter; a first aperture configured to transmit at least a portion of the first optical radiation from the first emitter; a first lenslet in optical communication with the first aperture; Equipped with the first cavity includes a first plurality of reflectors configured to reflect a portion of the first optical radiation toward the first opening; the first cavity, the first aperture, and the first lenslet are configured to cooperate to provide a first light output having optical characteristics suitable for coupling into the projector. Emitter system assembly.

2. 2. The emitter system assembly of claim 1, wherein the first cavity, the first aperture, and the first lenslet are configured to provide the first light output having at least one of a predetermined output direction and solid angle.

3. The emitter system assembly of claim 1 , further comprising a second emitter for providing a second light emission.

4. the first emitter provides the first optical radiation in a first wavelength range; the second emitter provides the second optical radiation in a second wavelength range, the second wavelength range being different from the first wavelength range; The emitter system assembly of claim 3 .

5. The emitter system assembly of claim 3 , wherein the first opening is configured to transmit at least a portion of both the first optical radiation and the second optical radiation.

6. a second cavity at least partially surrounding the second emitter; and a second aperture configured to transmit at least a portion of the second optical radiation from the second emitter; and a second lenslet in optical communication with the second aperture; and Further equipped with the second emitter, the second cavity, the second aperture, and the second lenslet are configured to provide a second light output having optical characteristics suitable for coupling into the projector. The emitter system assembly of claim 3 .

7. 7. The emitter system assembly of claim 6, further comprising a light baffle absorber for at least partially preventing crosstalk between said first light output and said second light output.

8. a third emitter for providing a third optical radiation in a third wavelength range, the third wavelength range being different from the first wavelength range and the second wavelength range; The emitter system assembly of claim 4 , wherein the first opening is configured to transmit at least a portion of the first optical radiation, the second optical radiation, and the third optical radiation.

9. The emitter system assembly of claim 1 , wherein the first lenslet is formed from a low index material.

10. The emitter system assembly of claim 1 , further comprising an anti-reflective layer on the first lenslet.

11. The emitter system assembly of claim 1 , further comprising an optical confinement structure disposed about the first emitter.

12. The emitter system assembly of claim 11 , wherein the light confinement structure comprises at least one of a reflective layer or a dielectric Bragg reflector.

13. 1. An emitter system assembly for providing a light output to a projector, comprising: a first emitter configured to provide a first light emission; a second emitter configured to provide a second light emission; a first cavity at least partially surrounding the first emitter; a second cavity at least partially surrounding the second emitter; and a first aperture configured to transmit at least a portion of the first optical radiation from the first emitter; a second aperture configured to transmit at least a portion of the second optical radiation from the second emitter; and a lenslet in optical communication with the first aperture and the second aperture; Equipped with the first cavity includes a first plurality of reflectors configured to reflect the first optical radiation within the first cavity toward the first opening; the second cavity includes a second plurality of reflectors configured to reflect the second optical radiation within the second cavity toward the second opening; the first cavity, the first aperture, the second cavity, the second aperture, and the lenslet are configured to cooperatively provide the first light radiation and the second light radiation as at least a portion of the light output to contribute to the light output having optical characteristics suitable for coupling into the projector. Emitter system assembly.

14. 14. The emitter system assembly of claim 13, wherein the first cavity, the first aperture, the second cavity, the second aperture, and the lenslets are configured to provide the light output having at least one of a predetermined output direction and solid angle.

15. 15. The emitter system assembly of claim 14, further comprising a light baffle absorber configured to prevent crosstalk between the first cavity and the second cavity.

16. 1. An emitter system assembly for providing a light output to a projector, comprising: a first emitter configured to provide a first light emission; a second emitter configured to provide a second light emission; a cavity at least partially surrounding the first emitter and the second emitter; an aperture configured to transmit at least a portion of the first optical radiation and the second optical radiation from the first emitter and the second emitter; a lenslet in optical communication with the aperture; Equipped with the cavity includes a plurality of reflectors configured to reflect the first optical radiation and the second optical radiation within the cavity toward the opening; the cavity, the aperture, and the lenslet are configured to cooperate to provide the light output having optical characteristics suitable for coupling into the projector. Emitter system assembly.

17. 17. The emitter system assembly of claim 16, wherein the cavity, the aperture, and the lenslet are configured to provide the light output having at least one of a predetermined output direction and solid angle.

18. 1. A method for forming an emitter system assembly, comprising: forming an emitter array on an emitter substrate; attaching the emitter array and the emitter substrate to a backplane; forming an array of cavities and an array of apertures respectively aligned with said emitter array; mounting an array of lenslets respectively aligned with said array of apertures; The method includes:

19. 20. The method of claim 18, further comprising the step of removing the emitter substrate after attaching the emitter substrate to the backplane, while leaving the emitter array attached to the backplane.

20. An array of pixels having a pitch between 1 micron and 100 microns, Each of the pixels is an emitter for providing optical radiation; a cavity at least partially surrounding the emitter and having a spatial opening configured to transmit a portion of the optical radiation; an optical element optically coupled to the spatial aperture; A display, wherein the lateral extent of the spatial aperture is smaller than the lateral extent of the emitter.

21. A display as described in claim 20, wherein the spatial aperture functions as an etendue gate for the emitter.

22. A display as described in claim 20, wherein the lateral extent of the spatial opening is smaller than the lateral extent of the optical element.

23. A display as described in claim 20, wherein the optical element is configured to transmit a portion of the optical radiation having predetermined optical properties.

24. The display of claim 20, wherein the optical element is configured to transmit a portion of the optical radiation having a predetermined output direction.

25. A display as described in claim 20, wherein the cavity includes a reflective material configured to reflect a portion of the optical radiation within the cavity toward the spatial opening.

26. The display of claim 25, wherein the reflective material is either silver or aluminum.

27. The display of claim 20, wherein the emitter includes three light-emitting diodes having red, green, and blue emissions, respectively.

28. The display of claim 20, wherein the emitter emits a color selected from red, green, and blue.

29. An augmented reality system comprising a display according to any one of claims 20 to 28.

30. A light emitting diode (LED) including a red LED emitter, a blue LED emitter, and a green LED emitter having respective light emissions; and respective cavities at least partially surrounding the red LED emitter, the blue LED emitter, and the green LED emitter; the respective cavities having respective spatial openings configured to transmit respective portions of the respective optical radiation; The display further comprising an optical element optically coupled to each of the spatial apertures.

31. A display as described in claim 30, wherein the lateral extent of each of the spatial openings is smaller than the lateral extent of each of the red LED emitters, the blue LED emitters, and the green LED emitters.

32. A display as described in claim 30, wherein the lateral extent of each of the spatial openings is smaller than the lateral extent of the optical element.

33. The display comprising a plurality of pixels; A display as claimed in any one of claims 30 to 32, wherein the red, blue and green LED emitters, the respective cavities and the optical element are comprised in one pixel of the plurality of pixels.

34. A light emitting diode (LED) including a red LED emitter, a blue LED emitter, and a green LED emitter having respective light emissions; and respective cavities at least partially surrounding the red LED emitter, the blue LED emitter, and the green LED emitter; the respective cavities having respective spatial openings configured to transmit respective portions of the respective optical radiation; The display further comprising respective optical elements optically coupled to said respective spatial apertures.

35. A display as described in claim 34, wherein the lateral extent of each of the spatial openings is smaller than the lateral extent of each of the red LED emitters, the blue LED emitters, and the green LED emitters.

36. A display as described in claim 34, wherein the lateral extent of each of the spatial openings is smaller than the lateral extent of each of the optical elements.

37. The display comprising a plurality of pixels; A display according to any one of claims 34 to 36, wherein the red, blue and green LED emitters, the respective cavities and the respective optical elements are comprised in one pixel of the plurality of pixels.

38. A light emitting diode (LED) including a red LED emitter, a blue LED emitter, and a green LED emitter having respective light emissions; a cavity at least partially surrounding the red LED emitter, the blue LED emitter, and the green LED emitter; the cavities having spatial openings configured to transmit respective portions of the respective optical radiation; The display further comprising an optical element optically coupled to the spatial aperture.

39. A display as described in claim 38, wherein the lateral extent of the spatial opening is smaller than the lateral extent of each of the red LED emitter, the blue LED emitter, and the green LED emitter.

40. A display as described in claim 38, wherein the lateral extent of the spatial opening is smaller than the lateral extent of the optical element.

41. The display comprising a plurality of pixels; A display according to any one of claims 38 to 40, wherein the red, blue and green LED emitters, the cavity and the optical element are comprised in one pixel of the plurality of pixels.

42. An LED mesa; a metallic contact disposed on a first portion of a top surface of the LED mesa; a dielectric layer disposed on a second portion of the top surface of the LED mesa; a reflective layer disposed on the dielectric layer and electrically insulated from the metallic contact.

43. The micro LED device of claim 42, wherein the dielectric layer and the reflective layer extend onto a sidewall of the LED mesa.

44. The semiconductor device according to claim 4, further comprising a second LED mesa adjacent to the LED mesa; 43. The micro LED device of claim 42, wherein the dielectric layer and the reflective layer extend on a second sidewall of the second LED mesa.

45. The micro LED device of claim 42, wherein the reflective layer overlaps the reflective layer along a cross section of the micro LED device.

46. A micro LED device as described in any one of claims 42 to 45, further comprising a cavity optically coupled to the LED mesa.

47. A method for manufacturing a light-emitting diode (LED) comprising: a first micro-LED emitter optically coupled to a first optical element; and a second micro LED emitter adjacent to the first micro LED emitter and optically coupled to a second optical element; a baffle disposed between the first micro LED emitter and the second micro LED emitter, the baffle configured to reduce optical crosstalk between the first micro LED emitter and the second micro LED emitter.

48. The display of claim 47, wherein the baffle comprises a light absorbing material.

49. The display of claim 47, wherein the baffle comprises a reflective material.

50. A display as described in any one of claims 47 to 49, wherein the baffle is configured to reduce re-entry of light emitted from at least one of the first micro LED emitter or the second micro LED emitter into the first micro LED emitter.

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