Patent ID: 12229940

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

DETAILED DESCRIPTION

Embodiments of the present disclosure relate to optical devices for augmented, virtual, and/or mixed reality applications. In one or more embodiments, an optical device metrology system is configured to measure a plurality of first metrics and one or more second metrics for optical devices, the one or more second metrics including a display leakage metric.

FIG.1Ais a perspective, frontal view of a substrate101, according to one implementation. The substrate includes a plurality of optical devices100disposed on a surface103of the substrate101. The optical devices100are waveguide combiners utilized for virtual, augmented, and/or mixed reality. The optical devices100may be part of the substrate101such that the optical devices100can be cut to be separated from the substrate101.

FIG.1Bis a perspective, frontal view of an optical device100, according to one implementation. It is to be understood that the optical devices100described herein are exemplary optical devices and that other optical devices (such as optical devices other than waveguide combiners) may be used with or modified to accomplish aspects of the present disclosure.

The optical device100includes a plurality of optical device structures102disposed on a surface103of a substrate101. The optical device structures102may be nanostructures having sub-micron dimensions (e.g., nano-sized dimensions). Regions of the optical device structures102correspond to one or more gratings104, such as a first grating104a, a second grating104b, and a third grating104c. In one embodiment, which can be combined with other embodiments, the optical device100includes at least the first grating104acorresponding to an input coupling grating and the third grating104ccorresponding to an output coupling grating. In one embodiment, which can be combined with other embodiments described herein, the optical device100also includes the second grating104bcorresponding to an intermediate grating. The optical device structures102may be angled or binary. The optical device structures102are rectangular. The optical device structures102may have other shapes including, but not limited to, circular, triangular, elliptical, regular polygonal, irregular polygonal, and/or irregular shaped cross-sections.

In operation (such as for augmented reality glasses), the input coupling grating104areceives incident beams of light (a virtual image) having an intensity from a microdisplay. The incident beams are split by the optical device structures102into T1 beams that have all of the intensity of the incident beams in order to direct the virtual image to the intermediate grating104b(if utilized) or the output coupling grating104c. In one embodiment, which can be combined with other embodiments, the T1 beams undergo total-internal-reflection (TIR) through the optical device100until the T1 beams come in contact with the optical device structures102of the intermediate grating104b. The optical device structures102of the intermediate grating104bdiffract the T1 beams to T-1 beams that undergo TIR through the optical device100to the optical device structures102of the output coupling grating104c. The optical device structures102of the output coupling grating104coutcouple the T-1 beams to the user's eye to modulate the field of view of the virtual image produced from the microdisplay from the user's perspective and further increase the viewing angle from which the user can view the virtual image. In one embodiment, which can be combined with other embodiments, the T1 beams undergo total-internal-reflection (TIR) through the optical device100until the T1 beams come in contact with the optical device structures102of the output coupling grating and are outcoupled to modulate the field of view of the virtual image produced from the microdisplay.

To facilitate ensuring that the optical devices100meet image quality standards, metrology metrics of the fabricated optical devices100are obtained prior to use of the optical devices100.

FIG.2is a schematic view of an optical device metrology system200, according to one implementation. Embodiments of the optical device metrology system200described herein provide for the ability to obtain multiple metrology metrics with increased throughput. The metrology metrics include an angular uniformity metric, a contrast metric, an efficiency metric, a color uniformity metric, a modulation transfer function (MTF) metric, a field of view (FOV) metric, a ghost image metric, an eye box metric, a display leakage metric, a see-through distortion metric, a see-through flare metric, a see-through ghost image metric, and a see-through transmittance metric. The throughput is increased via the utilization of a feeding system coupled to each of one or more subsystems of the optical device metrology system200.

The optical device metrology system200includes a first subsystem202, a second subsystem204, and a third subsystem206. Each of the first subsystem202, the second subsystem204, and the third subsystem206include a respective body201A-201C with a first opening203and a second opening205to allow a stage207to move therethrough along a stage path211that is parallel to and/or in the X-Y plane. The stage207is operable to move in an X-direction, a Y-direction, and a Z-direction in the bodies201A-201C of the first subsystem202, the second subsystem204, and the third subsystem206. The stage207includes a tray209operable to retain the optical devices100(as shown herein) or one or more substrates101. The stage207and the tray209may be transparent such that the metrology metrics obtained by the first subsystem202, the second subsystem204, and the third subsystem206are not impacted by the translucence of the stage207of the tray209. The first subsystem202, the second subsystem204, and the third subsystem206are in communication with a controller208operable to control operation of the first subsystem202, the second subsystem204, and the third subsystem206. The controller208includes instructions stored in a non-transitory computer readable medium (such as a memory). The instructions, when executed by a processor of the controller208, cause operations described herein to be conducted. The instructions, when executed by the processor of the controller208, cause one or more operations of one or more of the methods1000,1100, and/or1200to be conducted.

The instructions of the controller208include a machine learning algorithm and/or an artificial intelligence algorithm to optimize operations. In one embodiment, which can be combined with other embodiments, the instructions of the controller208include a machine learning (ML) model that is a regression model and averages data (such as metrics determined herein and/or image data collected using the alignment module494). In one example, which can be combined with other examples, the ML model is used to average and merge data to determine optimized pitches and tilts for projection structures, lenses, and cameras. In one example, which can be combined with other examples, the ML model is used to average and merge data to determine optimized powers to apply to light sources and laser sources to generate light beams and laser beams.

The first subsystem202is operable to obtain one or more metrology metrics including the angular uniformity metric, the contrast metric, the efficiency metric, the color uniformity metric, the MTF metric, the FOV metric, the ghost image metric, or the eye box metric. The second subsystem204is operable to obtain the display leakage metric. The third subsystem206is operable to obtain one or more see-through metrology metrics including the see-through distortion metric, the see-through flare metric, the see-through ghost image metric, or the see-through transmittance metric.

The optical device metrology system200is configured to determine a display leakage metric, one or more see-through metrics, and one or more other metrology metrics for a plurality of optical devices (such as waveguide combiners) on a single system using a single stage path211.

FIG.3Ais a schematic partial cross-sectional view of the first subsystem202shown inFIG.2, according to one implementation. The first subsystem202may include one or more of configurations400A,400B,400C,400D shown inFIGS.4A-4D.

As shown inFIG.3A, the first subsystem202includes an upper portion304oriented toward a top side of the optical devices100and a lower portion306oriented toward a bottom side of the optical device100.

The first subsystem202includes a first body201A having a first opening203and a second opening205to allow the stage207to move through the first opening203and the second opening205. The stage207is configured to move the tray209along the stage path211. The first subsystem202includes a first light engine310positioned within the first body201A and mounted above the stage path211. The first light engine310is an upper light engine. The first light engine310configured to direct first light beams toward the stage path211. In one embodiment, which can be combined with other embodiments, the first light beams are directed in a light pattern design toward the stage path211and toward one of the optical devices100for determination of metrology metrics. The first subsystem202includes a first detector312positioned within the first body201A and mounted above the stage path211to receive first projected light beams projected upwardly from the stage path211. The present disclosure contemplates that projected light can be light that is reflected from an optical device or transmitted through an optical device. The first detector312is a reflection detector. The first subsystem202includes a second detector316positioned within the first body201A and mounted below the stage path211to receive second projected light beams projected downwardly from the stage path211. The second detector316is a transmission detector. The first projected light beams and the second projected light beams are projected from an optical device100. In one embodiment, which can be combined with other embodiments, the first light engine310is configured to direct the first light beams toward the input coupling grating of an optical device100, and the first and second detectors312,316are configured to receive projected light beams that project from the output coupling grating of the optical device100.

The upper portion304of the first subsystem202includes an alignment detector308. The alignment detector308includes a camera. The alignment detector308is operable to determine a position of the stage207and the optical devices100. The lower portion306of the first subsystem202includes a code reader314mounted below the stage path211. The code reader314is operable to read a code of the optical devices100, such as a quick response (QR) code or barcode of an optical device100. The code read by the code reader314may include instructions for obtaining one or more metrology metrics for various optical devices100.

FIG.3Bis a schematic partial cross-sectional view of the second subsystem204shown inFIG.2, according to one implementation. The second subsystem204may include at least one configuration400E as shown inFIG.4E.

As shown inFIG.3B, the second subsystem204includes the upper portion304oriented toward a top side of the optical devices100and a lower portion oriented to toward a bottom side of the optical device100.

The second subsystem204includes a second body201B and a second light engine360positioned within the second body201B and mounted above the stage path211. The second light engine360configured to direct second light beams toward the stage path211. The upper portion304of the first subsystem202includes the alignment detector308.

The second subsystem204includes a face illumination detector318configured to receive third projected light beams projected upwardly from the stage path211. The third projected light beams are projected from an optical device100. The lower portion306of the second subsystem204includes the code reader314.

The face illumination detector318is operable to capture images to obtain the display leakage metric for the optical device100. In one embodiment, which can be combined with other embodiments, a light pattern design is directed from the second light engine360and toward the optical device100, and images of light outside a location of the user's eye are obtained and processed to obtain an eye box metric.

FIG.3Cis a schematic partial cross-sectional view of the third subsystem206shown inFIG.2, according to one implementation. The third subsystem206may include one or more configurations400F and/or400G as shown inFIGS.4F and4G.

As shown inFIG.3C, the third subsystem206includes an upper portion304oriented toward a top side of the optical devices100and a lower portion306oriented toward a bottom side of the optical device100. The third subsystem206includes a first light engine370mounted above the stage path211and configured to direct upper light beams toward the stage path211, a second light engine380mounted below the stage path211and configured to direct lower light beams toward the stage path211, and a detector390mounted above the stage path and configured to receive projected light beams projected from the stage path211. The upper portion304of the third subsystem206includes the alignment detector308. The detector390is a reflection detector. The detector390detects projected (e.g., reflected) light beams that project (e.g., reflect) from the output coupling grating from the top side of the optical devices100. The lower portion306of the third subsystem206includes the code reader314. Each of the first light engine370, the second light engine380, and the detector390are positioned within a third body201C of the third subsystem206.

FIG.4Ais a schematic view of a configuration400A of the first subsystem202shown inFIGS.2and3A, according to one implementation. The configuration400A includes the first light engine310, the first detector312, and the second detector316.

The first light engine310includes a first illuminator401, and the first illuminator401includes a first light source402and a first projection structure404. The first light engine310includes a first lens406positioned between the first illuminator401and the stage path211. The first light engine310includes one or more devices413(one is shown inFIG.4A) positioned between the first lens406and the stage path211. The one or more devices413includes one or more of a quarter wave plate or a linear polarizer. In one embodiment, which may be combined with other embodiments described herein, the first light engine310is configured to emit (e.g., project) light beams in a red spectrum, a green spectrum, and a blue spectrum. In one example, which can be combined with other examples, the first light engine310is configured to modulate or pulse light beams between the red spectrum, the green spectrum, and the blue spectrum. In one example, which can be combined with other examples, the first light engine310includes three light sources that are each configured to respectively emit light in the red spectrum, light in the green spectrum, and light in the blue spectrum.

The first projection structure404includes one or more of a display and/or a reticle. In one embodiment, which can be combined with other embodiments, the first projection structure404includes one or more of a microdisplay, a spatial light modulator (SLM), and/or a reticle. In one example, which can be combined with other examples, the SLM includes one or more of a digital micromirror device (DMD) and/or a liquid crystal on silicon (LCOS) emitter.

The first detector312includes a first camera412and a second lens410positioned between the first camera412and the stage path211. The second detector316includes a second camera416and a third lens414positioned between the second camera416and the stage path211. In the implementation shown inFIG.4A, the first projection structure404and the first lens406are oriented parallel to the stage path211.

The optical device100is positioned to align an input coupler121of the optical device100with the first light engine310, and to align an output coupler122of the optical device100with the first detector312and the second detector316. First light beams B1are directed from the first light engine310and toward the input coupler121of the optical device100. The first detector312captures a plurality of first images of first projected light beams BP1that project from the output coupler122in the red spectrum, the green spectrum, and the blue spectrum. The second detector316captures a plurality of second images of second projected light beams BP2that project from the output coupler122in the red spectrum, the green spectrum, and the blue spectrum.

The first images and the second images are full-field images. One or more of the first images and/or the second images are processed (such as by using the controller208) to determine a plurality of first metrics of the optical device100.

The plurality of first metrics include an angular uniformity metric. The angular uniformity metric can represent a ratio of light intensities across sections of light fields. For the angular uniformity metric, the processing of one or more of the plurality of first images or the plurality of second images includes comparing one or more first sections of a light pattern design with one or more second sections of the light pattern design within a single image. For the angular uniformity metric, the first light beams B1incoupled into the input coupler121undergo TIR until the incoupled first light beams B1are outcoupled (e.g., projected, such as reflected) to the first detector312.

The plurality of first metrics include a contrast metric. The contrast metric can represent a contrast between the brightest captured light within images and the darkest captured light within images. For the contrast metric, the processing of one or more of the plurality of first images or the plurality of second images includes comparing one or more bright sections of a light pattern design with one or more dark sections of the light pattern design within a single image. For the contrast metric, the first light beams B1incoupled into the input coupler121undergo TIR until the incoupled first light beams B1are outcoupled (e.g., projected, such as reflected) to the first detector312.

The plurality of first metrics include a color uniformity metric. The color uniformity metric can represent one or more ratios between the red light, the green light, and the blue light in a field. One or more of the plurality of first images, the plurality of second images, and/or the plurality of third images (described below in relation toFIG.4E) capture a red spectrum, a green spectrum, and a blue spectrum. For the color uniformity metric, the processing of one or more of the plurality of first images or the plurality of second images includes comparing a red spectrum image with a green spectrum image and a blue spectrum image using the same field area. For the color uniformity metric, the first light beams B1incoupled into the input coupler121undergo TIR until the incoupled first light beams B1are outcoupled (e.g., projected, such as reflected) to the first detector312.

The plurality of first metrics include an efficiency metric. For the efficiency metric, prior to the capturing of the plurality of first images and the capturing of the plurality of second images, the second detector316is positioned to align with the input coupler121of the optical device100in a calibration position (shown in ghost for the second detector316inFIG.4A). While the second detector316is in the calibration position, the first light engine310directs calibration light beams toward the input coupler121of the optical device100, and the second detector316captures one or more calibration images of calibration projected light beams CP1that project from the input coupler121of the optical device100. The one or more calibration images are full-field images. The second detector316is then positioned to align with the output coupler122of the optical device100. For the efficiency metric, the first light beams B1incoupled into the input coupler121undergo TIR until the incoupled first light beams B1are outcoupled (e.g., projected, such as reflected) to the first detector312and outcoupled (e.g., projected such as transmitted) to the second detector316. The first images are reflected images and the second images are transmitted images.

For the efficiency metric, the processing of one or more of the plurality of first images or the plurality of second images includes comparing the one or more calibration images with the plurality of first images and the plurality of second images.

The one or more first metrics include a modulation transfer function (MTF) metric. For the MTF metric, prior to the capturing of the plurality of first images and the capturing of the plurality of second images, directing calibration light beams from the first light engine301and toward the second detector316. The second detector316captures one or more calibration images of the calibration light beams while the second detector316is misaligned from the optical device100. The second detector316can be in the calibration position shown in ghost inFIG.4Aand aligned with the first light engine310, while the optical device100can be positioned away from the second detector316to be out of the fields-of-view of the second detector316and the first light engine310(as shown in ghost for the optical device100inFIG.4A). The second detector316can then be positioned to align with the first detector312. In one embodiment, which can be combined with other embodiments, the second images are captured prior to the capturing of the first images. For the MTF metric, the first light beams B1incoupled into the input coupler121undergo TIR until the incoupled first light beams B1are outcoupled (e.g., projected, such as reflected or transmitted) to the first detector312or the second detector316.

For the MTF metric, the processing of one or more of the plurality of first images or the plurality of second images includes comparing an outer edge of one or more sections of the one or more calibration images with the same outer edge of the same one or more sections of one or more of the plurality of first images or the plurality of second images.

The plurality of first metrics include an eye box metric. For the eye box metric, the first detector312or the second detector316is moved to scan across a plurality of locations along the output coupler122of the optical device100during the capturing of the plurality of first images or the capturing of the plurality of second images. The processing of one or more of the plurality of first images or the plurality of second images includes comparing different images that correspond to different field areas of the output coupler122. For the eye box metric, the first light beams B1incoupled into the input coupler121undergo TIR until the incoupled first light beams B1are outcoupled (e.g., projected, such as reflected or transmitted) to the first detector312or the second detector316.

The plurality of first metrics include a ghost image metric. For the ghost image metric, prior to the capturing of the plurality of first images and the capturing of the plurality of second images, calibration light beams are directed from the first light engine310and toward the second detector316. The second detector316captures one or more calibration images of the calibration light beams while the second detector316is misaligned from the optical device100. The second detector316can be in the calibration position shown in ghost inFIG.4Aand aligned with the first light engine310, while the optical device100can be positioned away from the second detector316to be out of the fields-of-view of the second detector316and the first light engine310(as shown in ghost for the optical device100inFIG.4A). The second detector316can then be positioned to align with the first detector312. In one embodiment, which can be combined with other embodiments, the second images are captured prior to the capturing of the first images.

For the ghost image metric, the processing of one or more of the plurality of first images or the plurality of second images includes comparing the one or more calibration images with one or more of the plurality of first images or the plurality of second images to determine an offset between the one or more calibration images and one or more of the plurality of first images or the plurality of second images. In one embodiment, which can be combined with other embodiments, the offset is an offset between a light pattern design (such as a reticle) in the one or more calibration images and the light pattern design (such as a reticle) in the first images or the second images.

FIG.4Bis a schematic view of a configuration400B of the first subsystem202shown inFIGS.2and3A, according to one implementation. The configuration400B includes the first light engine310, the first detector312, and the second detector316. The first light engine310includes the first light source402, the first projection structure404, and the first lens406. The first light engine310in the configuration400B includes one or more two-dimensional Galvano mirrors408(such as an array of two-dimensional Galvano mirrors) configured to turn the first light beams emitted by the first projection structure404along a 90-degree turn toward the stage path211. In the implementation shown inFIG.4B, the first projection structure404and the first lens406are oriented perpendicularly to the stage path211.

The first detector312includes the second lens410and the first camera412. The second detector316includes the third lens414and the second camera416. The first light engine310, using the one or more two-dimensional Galvano mirrors408, turns the first light beams B1along a 90 degree turn toward the stage path211and toward the input coupler121of the optical device100.

In the implementation shown inFIG.4Bthe first lens406is positioned between the first illuminator401and the stage path211along an optical path from the first illuminator and to the stage path211. The one or more two-dimensional Galvano mirrors408are positioned between the first lens406and the stage path211along the optical path. The optical path includes the 90 degree turn.

FIG.4Cis a schematic view of a configuration400C of the first subsystem202shown inFIGS.2and3A, according to one implementation. The configuration400C is similar to the configuration400A shown inFIG.4A, and includes one or more of the aspects, features, components, and/or properties thereof.

The configuration400C includes an alignment module494. The alignment module494is shown in relation to the first light engine310to align the first projection structure404and the first lens406. The alignment module494includes a laser source495, a beam splitter496, and an alignment detector497. The alignment module494includes a pinhole498formed in a plate499. The alignment detector497can include a camera. The alignment module494can be used in addition to the alignment detector308.

The alignment module494is used to conduct an alignment operation. In the alignment operation, the first light source402, the first projection structure404and the first lens406are moved out of alignment from the input coupler121of the optical device100. The alignment module494directs first laser light L1through the pinhole498and toward the optical device100using the laser source495. A light intensity of first reflected laser light RL1is determined using the alignment detector497. The first reflected laser light RL1is that first laser light L1that reflects off of the optical device100. The first reflected laser light RL1is directed to the alignment detector497using the beam splitter496. A tilt and a pitch of the laser source495is adjusted to increase the light intensity to an increased light intensity. A first position of the first reflected laser light RL1received by the alignment detector497is determined at the increased light intensity. The first position is a position of the first reflected laser light RL1within an image that the alignment detector497captures of the first reflected laser light RL1.

In the alignment operation, the first lens406is moved to be aligned with the input coupler121of the optical device100(as shown in ghost inFIG.4C), and second laser light is directed through the pinhole498and toward the first lens406. A tilt and a pitch of the first lens406is adjusted until a second position of second reflected laser light received by the alignment detector matches the first position of the first reflected laser light RL1. The second reflected laser light is the second laser light that reflects off of the first lens406and back toward the beam splitter496.

In the alignment operation, the first projection structure404is moved to be aligned with the input coupler121of the optical device100(as shown in ghost inFIG.4C), and third laser light is directed through the pinhole498and toward the first projection structure404. A tilt and a pitch of the first projection structure404is adjusted until a third position of third reflected laser light received by the alignment detector matches the first position of the first reflected laser light RL1. The third reflected laser light is the third laser light that reflects off of the first projection structure404and back toward the beam splitter496.

The alignment module494can then be moved out of alignment from the input coupler121of the optical device100, and the first light source402can be moved into alignment with the input coupler121of the optical device100. Lenses, projection structures, and cameras can be aligned using the alignment module494and the alignment operation to facilitate accurate operations, such as accurate determination of metrics of optical devices100. The operations described for the alignment operation can be combined with the methods1000,1100,1200described below.

FIG.4Dis a schematic view of a configuration400D of the first subsystem202shown inFIGS.2and3A, according to one implementation. The configuration400D includes the first light engine310, the first detector312, and the second detector316. The first light engine310includes the first light source402, the first projection structure404, a first lens406apositioned between the first illuminator401, and a lens406bpositioned between the first lens406aand the stage path211. The first light engine310includes an adjustable aperture407positioned between the lens406band the first lens406a. The adjustable aperture407can be formed in a plate415. The adjustable aperture407can be adjusted by moving the adjustable aperture407upward and downward (such as by moving the plate415) and/or by opening and closing the adjustable aperture407.

The first light engine310can include the one or more devices413shown inFIG.4Apositioned between the lens406band the stage path211. The first detector312includes a second lens410and a first camera412. The second detector316includes a third lens414and a second camera416. In one embodiment, which can be combined with other embodiments, each of the first lens406, the first lens406a, the lens406b, the second lens410and/or the third lens414is formed of the same convex lens structure having the same radius of curvature. Each of the first lens406, the first lens406a, the lens406b, the second lens410and/or the third lens414has the same lens structure. Using the same lens structure for the lenses facilitates compensating for optic aberrations, such as aberrations in reflection and/or transmission of light.

FIG.4Eis a schematic view of a configuration400E of the second subsystem204shown inFIGS.2and3B, according to one implementation. The configuration400E includes the second light engine360and the face illumination detector318. The second light engine360includes a second illuminator461and a fourth lens466positioned between the second illuminator461and the stage path211. The second illuminator461includes a second light source462and a second projection structure464. The second projection structure464and the fourth lens466are oriented parallel to the stage path211.

The second projection structure464includes one or more of a display and/or a reticle. In one embodiment, which can be combined with other embodiments, the second projection structure464includes one or more of a microdisplay, a spatial light modulator (SLM), and/or a reticle. In one example, which can be combined with other examples, the SLM includes one or more of a digital micromirror device (DMD) and/or a liquid crystal on silicon (LCOS) emitter.

The face illumination detector318includes a third camera426, a fifth lens424positioned between the third camera426and the stage path211, and an eye box blocker420positioned between the fifth lens424and the stage path211. The eye box blocker420is adjacent a face level422.

The optical device100is positioned to align the input coupler121with the second light engine360, and to align the output coupler122with the face illumination detector318. Second light beams B2are directed from the second light engine360and toward the input coupler121of the optical device100. The face illumination detector318captures a plurality of third images (in addition to the first images and the second images described in relation toFIG.4A) of third projected light beams BP3that project from the output coupler122of the optical device100.

The plurality of third images include the third projected light beams BP3that project from the output coupler122of the optical device100and past the eye box blocker420of the face illumination detector318. The plurality of third images are processed (such as by using the controller208) to determine one or more second metrics of the optical device. The one or more second metrics include a display leakage metric.

FIG.4Fis a schematic view of a configuration400F of the third subsystem206shown inFIGS.2and3C, according to one implementation. The third subsystem206includes the first light engine310mounted above the stage path211and configured to direct upper light beams toward the stage path211, and a second light engine322mounted below the stage path211and configured to direct lower light beams toward the stage path211.

The configuration400F includes a detector320mounted above the stage path211and configured to receive projected light beams projected from the stage path211. The projected light beams project from the optical device100. The first light engine310includes the first illuminator401and the first lens406. The detector320includes the second lens410and the first camera412. The second light engine322includes a device and a third lens.

The second light engine322comprises a second illuminator471and a second lens476positioned between the second illuminator471and the stage path211. The second illuminator471includes a second light source472and a second projection structure474. The second projection structure474is a display or a reticle. In one embodiment, which can be combined with other embodiments, a see-through transmittance metric of the optical device100is obtained using the configuration400F by illuminating the output coupling grating of the optical device100with the lower light beams emitted by the second light engine322.

The input coupler121of the optical device100is aligned with the first light engine310and the output coupler122is aligned with the second light engine322, as shown inFIG.4F. The detector320is aligned (e.g., vertically) with the second light engine322and misaligned from the first light engine310. The second light engine322directs first light beams LB1toward the output coupler122. Upper light beams LB2can be directed toward the input coupler121of the optical device100from the first light engine310. Using the detector320, a plurality of first images are captured of the first light beams LB1that transmit through the output coupler122and project from the output coupler322as first projected light beams PB1. The optical device100is positioned away from the second light engine322to misalign the optical device100from the second light engine322(as shown in ghost inFIG.4Ffor the optical device100) and position the optical device100out of field-of-views of the second light engine322and the detector320. Second light beams are directed from the second light engine322and toward the detector320. The detector captures a plurality of second images of the second light beams that project from the waveguide combiner as second projected light beams. The first images and the second images are full-field images. The first light beams and the second light beams are emitted (sequentially, for example) from the light engine in a red spectrum, a green spectrum, and a blue spectrum. The plurality of first images and the plurality of second images respectively capture the first light beams and the second light beams in the red spectrum, the green spectrum, and the blue spectrum. In one embodiment, which can be combined with other embodiments, the second images are captured prior to the first images.

The second images are compared with the first images (such as by using the controller208) to determine a see-through transmittance metric of the optical device100. In one embodiment, which can be combined with other embodiments, the comparing includes comparing a second light intensity of the plurality of second images with a first light intensity of the plurality of first images

FIG.4Gis a schematic view of a configuration400G of the third subsystem206shown inFIGS.2and3C, according to one implementation. The configuration400G includes the detector320, and the first light engine310. The configuration400G includes a patterned substrate490positioned below the stage path211. The patterned substrate490includes a pattern design formed thereon. Each of the first light engine310, the patterned substrate490, and the detector320are positioned within the third body201C of the third subsystem206. In one embodiment, which can be combined with other embodiments, the patterned substrate490includes one or more of a plurality of protuberances493and/or a plurality of recesses489(shown in ghost inFIG.4G) that form the pattern design.

In an aligned position shown inFIG.4G, the patterned substrate490is aligned at least partially below the detector320, and the patterned substrate490is misaligned at least partially from the first light engine310. The optical device100below the detector320to align the optical device100with the detector320, and the optical device100is positioned above the patterned substrate490at a distance D1from the patterned substrate490.

The patterned substrate490directs lower light beams491toward the optical device100. The lower light beams491are reflected off of an upper surface of the patterned substrate490toward the optical device100. The lower light beams491transmit through the optical device100and are captured using the detector320. In one embodiment, which can be combined with other embodiments, the patterned substrate490reflects ambient light as the lower light beams491. In one embodiment, which can be combined with other embodiments, the patterned substrate490reflects light from a light engine, such as the second light engine322. In one embodiment, which can be combined with other embodiments, the configuration400G includes the second light engine322configured to direct light beams toward the patterned substrate490, and the patterned substrate490reflects the light beams from the second light engine322as the lower light beams491. The first light engine310includes the first light source402, the first projection structure404, and the first lens406. The detector320includes the second lens410and the first camera412.

The detector320captures a plurality of first images of projected light beams492that project from the output coupler122of the optical device100while the patterned substrate490is partially aligned with the detector320and partially misaligned from the detector320(as shown inFIG.4G). The plurality of first images capture a red spectrum, a green spectrum, and a blue spectrum of the projected light beams492. The plurality of first images are processed (such as by the controller208) to determine one or more see-through metrics of the optical device100.

The one or more see-through metrics include a see-through flare metric. For the see-through flare metric, the optical device100is positioned below the first light engine310to align the input coupler121of the optical device100with the first light engine310. First light beams LB3are directed from the first light engine310and toward the input coupler121of the optical device100. In such an embodiment, the projected light beams492include first light beams LB3from the first light engine310and lower light beams491reflected from the patterned substrate490. The first light beams LB3are emitted from the first light engine310in a light pattern design that is different from the pattern design of the patterned substrate490.

The one or more see-through metrics include one or more of a see-through distortion metric and/or a see-through transmittance metric. For the see-through distortion metric and/or the see-through transmittance metric, the projected light beams492include light beams491reflected from the patterned substrate490. The optical device100is positioned away from the detector320to misalign the optical device100from the detector320and the patterned substrate490(as shown in ghost for the optical device100inFIG.4G) and position the optical device100out of field-of-views of the patterned substrate490and the detector320. The detector320captures a plurality of second images of reflected light beams that reflect from the patterned substrate490and toward the detector320. The plurality of second images capture the reflected light beams in the red spectrum, the green spectrum, and the blue spectrum. The processing of the plurality of first images includes comparing the plurality of second images with the plurality of first images to determine the see-through distortion metric and/or the see-through transmittance metric. In one embodiment, which can be combined with other embodiments, the second images are captured prior to capturing of the first images.

The one or more see-through metrics include a see-through ghost image metric. For the see-through ghost image metric, the optical device100is positioned away from the detector320to misalign the optical device100from the detector320and the patterned substrate490. The detector320captures a plurality of second images of reflected light beams that reflect from the patterned substrate490using the detector320. The plurality of second images capture the reflected light beams in the red spectrum, the green spectrum, and the blue spectrum. The processing of the plurality of first images includes determining an offset between the plurality of second images and the plurality of first images. In one embodiment, which can be combined with other embodiments, the offset is an offset between the pattern design (such as a reticle) in the first images and the pattern design (such as a reticle) in the second images.

FIG.5is a schematic view of an image500, according to one implementation. The image500includes a light pattern design (such as a reticle) having dark sections501and bright sections502. The image500can be used to determine the contrast metric and/or the angular uniformity metric.

For the angular uniformity metric, the processing includes comparing one or more first sections502aof the light pattern design with one or more second sections502b,502cof the light pattern design within the image500. The first and second sections502a,502b,502ccorrespond to bright sections502. The processing includes comparing light intensities of the one or more first sections502awith light intensities of the one or more second sections502b,502c. The sections502a,502b,502care disposed at different radii relative to a center of the image500.

For the contrast metric, the processing includes comparing a light intensity of one or more bright sections502aof the light pattern design with a light intensity of one or more dark sections501aof the light pattern design within the image500. The bright section502ahas a light intensity I1and the dark section501ahas a light intensity I2. The contrast metric can be determined and represented by the following Equation 1 as “C”:

C=I⁢⁢1-I⁢⁢2I⁢⁢1-I⁢⁢2(Equation⁢⁢1)

FIGS.6A-6Care schematic views of images610,620,630, according to one implementation.FIG.6Ashows a red image610,FIG.6Bshows a green image620, andFIG.6Cshows a blue image630. The images610,620,630are used to determine the color uniformity metric. The processing includes comparing the images610,620,630using the same field area in each respective image610,620,630. The same field area includes one or more bright sections602a-602c,603a-603cat the same position in each image610,620,630. The color uniformity metric can represent a ratio of light intensities of the one or more bright sections602a-602c,603a-603cin each image610,620,630.

FIGS.7A-7Care schematic views of images710,720,730, according to one implementation.FIG.7Ashows a calibration image710,FIG.7Bshows a first image (e.g., a reflected image), andFIG.7Cshows a second image (e.g., a transmitted image). The images710,720,730can be used to determine the efficiency metric.

The processing includes comparing the calibration image710with the first image720and the second image730using the same field area in each respective image710,720,730. The same field area includes one or more bright sections702a-702cat the same position in each image710,720,730. The processing includes comparing light intensities of the one or more bright sections702a-702cin the images710,720,730. The calibration image710includes a light intensity IC1for the bright section702a, the first image720includes a light intensity IR1for the bright section702b, and the second image730includes a light intensity IT1for the bright section702c.

The efficiency metric can be determined and represented by the following Equation 2 as “E”:

E=(IR⁢⁢1IC⁢⁢1)*(IT⁢⁢1IC⁢⁢1)(Equation⁢⁢2)

FIG.8is a schematic view of an image800, according to one implementation. The image800includes a light pattern design (such as a reticle) having dark sections and bright sections. The image800can be used to determine the MTF metric. The processing includes comparing an edge area832of the one or more calibration images with the same edge area (e.g., the same position within the image) of the same one or more sections of one or more of the plurality of first images or the plurality of second images. The edge area832at least partially encompasses an outer edge831of one or more sections (such as a bright section).

FIGS.9A-9Care schematic views of images910,920,930, according to one implementation. Each of the images910,920,930shows a light pattern design that can be used for light directed by the first light engine310, the first light engine370, the second light engine360, the first light engine370, the second light engine380, the second light engine322, and/or the patterned substrate490. Each of the images910,920,930can be used to determine the ghost image metric and/or other metrics (such as other first metrics). Each of the images910,920,930respectively includes a plurality of dark sections901a-901cand a plurality of bright sections902a-902c.

FIG.10is a schematic block diagram view of a method1000of analyzing optical devices, according to one implementation.

Operation1002of the method1000includes positioning an optical device within a first subsystem to align the optical device with a first detector and a second detector of the first subsystem.

Operation1004includes directing first light beams from a first light engine of the first subsystem and toward the optical device. In one embodiment, which can be combined with other embodiments, the directing includes turning the first light beams along a 90 degree turn toward the stage path.

Operation1006includes capturing a plurality of first images of first projected light beams that project from the optical device using the first detector of the first subsystem.

Operation1008includes capturing a plurality of second images of second projected light beams that project from the optical device using the second detector of the first subsystem.

Operation1010includes processing one or more of the plurality of first images or the plurality of second images to determine a plurality of first metrics of the optical device. The first metrics include an angular uniformity metric, a contrast metric, an efficiency metric, a color uniformity metric, a modulation transfer function (MTF) metric, a field of view (FOV) metric, a ghost image metric, and/or an eye box metric.

Operation1012includes positioning the optical device within a second subsystem to align the optical device with a face illumination detector of the second subsystem.

Operation1014includes directing second light beams from a second light engine of the second subsystem and toward the optical device.

Operation1016includes capturing a plurality of third images of third projected light beams that project from the optical device using the face illumination detector of the second subsystem.

Operation1018includes processing the plurality of third images to determine one or more second metrics of the optical device. The one or more second metrics include a display leakage metric.

FIG.11is a schematic block diagram view of a method1100of analyzing optical devices, according to one implementation.

Operation1102of the method1100includes positioning an optical device above a light engine to align the optical device with the light engine.

Operation1104includes directing first light beams from the light engine and toward the optical device.

Operation1106includes capturing a plurality of first images of the first light beams that project from the optical device as first projected light beams using a detector.

Operation1108includes positioning the optical device away from the light engine to misalign the optical device from the light engine.

Operation1110includes directing second light beams from the light engine and toward the detector.

Operation1112includes capturing a plurality of second images of the second light beams.

Operation1114includes comparing the plurality of second images with the plurality of first images to determine a see-through transmittance metric of the optical device.

FIG.12is a schematic block diagram view of a method1200of analyzing optical devices, according to one implementation.

Operation1202of the method1200includes positioning an optical device below a detector to align the optical device with the detector.

Operation1204includes positioning the optical device above a patterned substrate at a distance from the patterned substrate. The patterned substrate includes a pattern design formed thereon.

Operation1206includes capturing a plurality of first images of projected light beams that project from the optical device using a detector while the patterned substrate is at least partially aligned with the detector.

Operation1208includes processing the plurality of first images to determine one or more see-through metrics of the optical device. The one or more see-through metrics include one or more of a see-through transmittance metric, a see-through distortion metric, a see-through flare metric, and/or a see through ghost image metric.

Benefits of the present disclosure include using a single optical device metrology system200to determine multiple metrology metrics (such as a display leakage metric, one or more see-through metrics, and one or more other metrology metrics) for a plurality of optical devices (such as waveguide combiners) on a single system using a single stage path211. In one embodiment, which can be combined with other embodiments, a single system using a single stage path211can be used to determine a display leakage metric, an angular uniformity metric, a contrast metric, an efficiency metric, a color uniformity metric, a modulation transfer function (MTF) metric, a field of view (FOV) metric, a ghost image metric, an eye box metric, a see-through distortion metric, a see-through flare metric, a see-through ghost image metric, and a see-through transmittance metric. Benefits also include increased throughput, reduced delays and costs, and enhanced efficiencies. The throughput is increased via the utilization of a feeding system coupled to each subsystem of the optical device metrology system.

It is contemplated that one or more aspects disclosed herein may be combined. As an example, one or more aspects, features, components, and/or properties of the optical device metrology system200, the first subsystem202, the second subsystem204, the third subsystem206, the configuration400A, the configuration400B, configuration400C, the configuration400D, the configuration400E, the configuration400F, the configuration400G, the image500, the images610-630, the images710-730, the image800, the images910-930, the method1000, the method1100, and/or the method1200may be combined. As an example, one or more of the operations described in relation to the optical device metrology system200, the subsystems202,204,206, and/or the configurations400A-400G can be combined with one or more of the operations described in relation to the method1000, the method1100, and/or the method1200. Moreover, it is contemplated that one or more aspects disclosed herein may include some or all of the aforementioned benefits.

While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.