Folding mirror illumination for compact optical measurement systems

Abstract

Embodiments of the present disclosure generally relate to measurement systems and measurement methods for measuring waveguides for image quality criteria. In at least one embodiment, the optical device measurement system includes a stage, a body, and an optical engine located within the body and mounted above the stage. The optical engine includes a light source, a folding mirror angled with respect to the light source and configured to redirect rays toward the stage, one or more lenses or arrays located between the folding mirror and the stage, and a projection lens located between the one or more lenses or arrays and the stage. The system further includes a first detector located within the body and mounted above the stage adjacent to the optical engine and configured to receive projected rays projected upward from the stage.

Description

Technical Field

[0001]

[0001] Embodiments of the present disclosure generally relate to measurement of waveguides. More specifically, the embodiments described herein provide measurement systems and methods for measurement of waveguides. Background Art

[0002] Description of Related Art

[0002] Virtual reality is generally considered a computer-generated simulated environment in which a user has an apparent physical presence. Virtual reality experiences can be generated in 3D and viewed with a head-mounted display (HMD) (e.g., glasses or other wearable display devices having a near-eye display panel as a lens for displaying a virtual reality environment that replaces the actual physical environment).

[0003]

[0003] However, augmented reality enables an experience in which not only can a user view the surrounding environment through the display lens of glasses or other HMD devices, but the user can also view images of virtual objects generated for display that appear as part of the environment. Augmented reality may include any type of input (e.g., voice input and haptic input), as well as virtual images, graphics, and video that enhance or extend the environment experienced by the user. There are many challenges and design constraints in state-of-the-art augmented reality technology.

[0004]

[0004] Accordingly, what is needed in the art is a measurement system and a measurement method for measuring waveguides for image quality standards. Summary of the Invention

[0005]

[0005] Embodiments of the present disclosure generally relate to measurement systems and measurement methods for measuring waveguides for image quality criteria. More specifically, embodiments described herein provide a compact measurement system that utilizes mirror-folding illumination to measure multiple indicators.

[0006]

[0006] In at least one embodiment, an optical device measurement system is provided. The measurement system includes a stage configured to move a tray along a stage path, and a body having a first opening and a second opening to allow the stage to move through a first opening and a second opening. The system further includes an optical engine located within the body and mounted above the stage, configured to direct rays toward the stage. The optical engine includes a light source, a folding mirror angled with respect to the light source and configured to redirect rays toward the stage, one or more lenses or arrays located between the folding mirror and the stage along the optical path, and a projection lens located between the one or more lenses or arrays and the stage along the optical path. The system further includes a first detector located within the body and mounted above the stage adjacent to the optical engine, configured to receive projected rays projected upward from the stage.

[0007]

[0007] In at least one embodiment, an optical device measurement system is provided. The measurement system includes a stage configured to move a tray along a stage path, and a body having a first opening and a second opening to allow the stage to move through a first opening and a second opening. The system further includes an optical engine located within the body and mounted above the stage, configured to direct rays toward the stage. The optical engine includes a light source, a first folding mirror angled with respect to the light source, a second folding mirror opposite the first folding mirror and configured to redirect rays toward the stage, one or more lenses or arrays located between the second folding mirror and the stage along the optical path, and a projection lens located between the one or more lenses or arrays and the stage along the optical path. The system further includes a first detector located within the body and mounted above the stage adjacent to the optical engine, configured to receive projection rays projected upward from the stage.

[0008]

[0008] In at least one embodiment, a method for analyzing an optical device is provided. The method includes positioning the optical device within a measurement system and directing a ray from an optical engine toward the optical device. Directing the ray includes projecting a ray from the light source of the optical engine onto a first folding mirror, changing the direction of the ray toward the optical device, and projecting the ray onto one or more lenses or arrays and projecting it toward the optical device through the projection lens. The method further includes using a first detector to capture a plurality of first images of the projected ray projected from the optical device, and processing one or more of the plurality of first images to determine a plurality of first indicators of the optical device.

[0009]

[0009] To enable a more detailed understanding of the features of the present disclosure described above, a more specific description of the present disclosure, which has been briefly summarized above, can be obtained by referring to embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings show only exemplary embodiments and should not be considered to limit the scope of the present disclosure, and other equally valid embodiments are permitted. [Brief explanation of the drawing]

[0010] [Figure 1A]

[0010] This is a perspective front view of a substrate according to an embodiment described herein. [Figure 1B]

[0011] This is a perspective front view of a waveguide according to an embodiment described herein. [Figure 2]

[0012] This is a schematic diagram of a measurement system according to an embodiment described herein. [Figure 3]

[0013] This is a schematic diagram of the optical engine and reflection detector of a measurement system according to an embodiment described herein. [Figure 4]

[0014] This is a schematic diagram of the optical engine of a measurement system according to an embodiment described herein. [Modes for carrying out the invention]

[0011]

[0015] For ease of understanding, the same reference numerals have been used to indicate identical elements common to the figures where possible. It is assumed that elements and features of one embodiment can be usefully incorporated into other embodiments without further description.

[0012]

[0016] Embodiments of this disclosure generally relate to measurement systems and measurement methods for measuring waveguides for image quality criteria. More specifically, embodiments described herein provide a compact measurement system that utilizes mirror-folding illumination to measure multiple metrics. It has been found that the distance between the optical engine and the reflectance detector of the measurement system can be shortened by folding the illumination optical system using one or more folding mirrors, resulting in the compact measurement system described herein.

[0013]

[0017] Figure 1A is a perspective front view of a substrate 100 according to an embodiment described herein. The substrate includes a plurality of waveguides 102 arranged on the surface 101 of the substrate 100. The waveguides 102 are waveguide combiners used for virtual reality, augmented reality, or mixed reality.

[0014]

[0018] Figure 1B is a perspective front view of waveguide 102. It should be understood that waveguide 102 described herein is an exemplary waveguide, and other waveguides may be used together or modified to achieve embodiments of this disclosure. Waveguide 102 includes a plurality of waveguide structures 103 arranged on the surface 101 of substrate 100. Waveguide structures 103 may be nanostructures having submicron dimensions (e.g., nanoscale dimensions). Regions of waveguide structures 103 correspond to one or more grids 104, such as a first grid 104a, a second grid 104b, and a third grid 104c. In one embodiment, which can be combined with other embodiments described herein, waveguide 102 includes at least a first grid 104a corresponding to an input coupling grid and a third grid 104c corresponding to an output coupling grid. In another embodiment, which can be combined with other embodiments described herein, waveguide 102 further includes a second grid 104b corresponding to an intermediate grid. The waveguide structure 103 may be angled or binary. The waveguide structure 103 may have other cross-sections, including but not limited to circular, triangular, elliptical, regular polygon, irregular polygon, and / or irregular shapes.

[0015]

[0019] During operation, the first grating 104a receives an incident beam of light with intensity from the optical engine. In one embodiment, which can be combined with other embodiments described herein, the optical engine is a microdisplay. To direct a virtual image onto an intermediate grating (if used) or a third grating 104c, the incident beam is split by the waveguide structure 103 into beams with the full intensity of the incident beam. The beams undergo total internal reflection (TIR) ​​through the waveguide 102 until they contact the waveguide structure 103 of the third grating 104c, and are output to display the virtual image produced by the optical engine.

[0016]

[0020] To ensure that the waveguide 102 meets image quality standards, it is necessary to obtain measurement metrics for the manufactured waveguide 102. Each measurement metric of the waveguide 102 is tested to ensure that predetermined values ​​are achieved. Embodiments of the measurement system 200 described herein provide the ability to acquire multiple measurement metrics with improved throughput. The measurement metrics include one or more of the following: angular uniformity metric, contrast metric, efficiency metric, color uniformity metric, modulation transfer function (MTF) metric, field of view (FOV) metric, ghost image metric, and eyebox metric.

[0017]

[0021] Figure 2 is a schematic cross-sectional view of a measurement system 200 according to an embodiment described herein. The measurement system 200 includes a body 201 having a first opening 203 and a second opening 205 through which a stage 207 can move. The stage 207 is operable to move in the X, Y, and Z directions within the body 201 of the measurement system 200. The stage 207 includes a tray 209 operable to hold a waveguide 102 (as shown herein), or one or more substrates 101 having the waveguide 102 on it.

[0018]

[0022] The measurement system 200 is operable to acquire one or more measurement metrics, including one or more of the following: angular uniformity metric, contrast metric, efficiency metric, color uniformity metric, MTF metric, FOV metric, ghost image metric, or eyebox metric. The stage 207 and tray 209 may be transparent. This ensures that the measurement metrics acquired by the measurement system 200 are not affected by the translucency of the stage 207 or tray 209. The measurement system 200 communicates with the controller 220. The controller 220 is operable to facilitate the operation of the measurement system 200.

[0019]

[0023] The measurement system 200 includes an upper section 204 oriented toward the upper surface 222 of the waveguide 102 and a lower section 206 oriented toward the bottom surface 224 of the waveguide 102. The upper section 204 of the measurement system 200 includes a positioning camera 208, an optical engine 210, and a reflectance detector 212. The positioning camera 208 is operable to determine the position of the stage 207. The positioning camera 208 is also operable to determine the position of the waveguide 102 positioned on the stage 207. The positioning camera 208 includes a positioning camera body 211. The optical engine 210 is operable to project light. For example, the optical engine 210 is operable to illuminate the first grating 104a of the waveguide 102. The optical engine 210 includes an optical engine body 213. In one embodiment, which can be combined with other embodiments described herein, the optical engine 210 projects a pattern onto the first grating 104a. The reflection detector 212 detects the output beam projected from the third grating 104c of the waveguide 102. The reflection detector 212 includes a reflection detector body 215. The output beam may be emitted from the top surface 222 or the bottom surface 224 of the waveguide 102. The output beam may correspond to a pattern from the optical engine 210. The reflection detector 212 detects one or more images of the pattern. One or more images of the pattern may be processed by the controller 220 to extract each measurement index.

[0020]

[0024] The lower part 206 of the measurement system 200 includes a code reader 214 and a transmission detector 216. The code reader 214 and transmission detector are positioned opposite the alignment camera 208, the optical engine 210, and the reflection detector 212 relative to the stage 207. The code reader 214 is operable to read codes on the waveguide 102, such as quick response (QR) codes or barcodes on the waveguide 102. The codes read by the code reader 214 may contain identification information and / or instructions for obtaining one or more measurement indicators of the waveguide 102. The transmission detector 216 detects the output beam projected from the third grating 104c through the bottom surface 224 of the waveguide 102. In one embodiment, which can be combined with other embodiments described herein, the transmission detector 216 is coupled to a transmission detector stage 226. The transmission detector stage 226 is operable to move the transmission detector 216 in the X, Y, and Z directions. The transmission detector stage 226 is operable to adjust the position of the transmission detector 216 in order to enhance the detection of the output beam projected from the third grating 104c.

[0021]

[0025] The controller 220 is connected to the measurement system 200. The controller 220 includes a processor 252, memory 254, and interconnected support circuits 256. The controller 220 is electrically connected to the measurement system 200 via wires 258. The processor 252 may be any form of general-purpose microprocessor or general-purpose central processing unit (CPU) that can be used in an industrial environment, such as a programmable logic controller (PLC), supervisory control and data acquisition (SCADA) system, general-purpose graphics processing unit (GPU), or other suitable industrial controller. The memory 254 is non-transient and may be one or more readily available memories, such as random access memory (RAM), read-only memory (ROM), or any other form of local or remote digital storage. The memory 254 contains instructions, which, when executed by the processor 252, facilitate the execution of methods. Instructions in memory 254 take the form of a program product, such as a program that implements the method of the present disclosure. The program code of the program product may conform to any one of several different programming languages. Exemplary computer-readable storage media include, but are not limited to, (i) a non-write storage medium on which information is permanently stored (e.g., a read-only memory device in a computer, such as a CD-ROM disk readable by a CD-ROM drive, flash memory, a ROM chip, or any type of solid non-volatile semiconductor memory), and (ii) a writable storage medium in which changeable information is stored (for example, a floppy disk in a disk drive or a hard disk drive, or any type of solid random access semiconductor memory). When such a computer-readable storage medium carries computer-readable instructions directed to the functions of the method described in the present specification, it constitutes an embodiment of the present disclosure.

[0022]

[0026] Figure 3 is a schematic diagram of an optical engine and a reflection detector of a measurement system according to an embodiment described in the present specification.

[0023]

[0027] In some embodiments, the optical engine 210 includes a light source 260 such as an LED that emits light to a folding mirror 262. The folding mirror 262 is angled with respect to the light source 260. The folding mirror 262 is oriented at an angle of from about 30 degrees to about 70 degrees to one side of the optical engine 210 in the direction of the light source 260. The angle of the folding mirror 262 can reduce the distance between the optical engine 210 and the reflection detector 212, thereby providing space for positioning the reflection detector 212 above the third grating 104c. Reducing the distance also enables reduction of the footprint of the optical engine 210 and the reflection detector 212. The distance between the optical engine 210 and the reflection detector 212 may be from about 10 millimeters (mm) to about 20 mm, for example about 15 mm. The distance from the first end of the optical engine 210 distal to the reflection detector 212 to the second end of the reflection detector 212 distal to the optical engine 210 may be from about 30 mm to about 70 mm, for example about 50 mm.

[0024]

[0028] Light is projected through a projection lens 266 of the optical engine 210 onto a series 264 of lenses and / or arrays. The reflection detector 212 captures the light reflected from the waveguide 102 and evaluates its performance based on the test pattern projected by the optical engine 210. The reflection detector 212 includes a camera lens 268 and a camera 270.

[0025]

[0029] Figure 4 is a schematic diagram of the optical engine of the measurement system according to the embodiment described herein.

[0026]

[0030] In some embodiments, the optical engine 210 includes a light source 260 positioned on one or more folding mirrors 262. Light emitted from the light source 260 is projected onto a first folding mirror 262A through a lens 276. The first folding mirror 262A is angled relative to the light source 260 so that the projected light is reflected onto a second folding mirror 262B. The first and second folding mirrors 262A and 262B are oriented toward opposing sides of the optical engine 210. The second folding mirror 262B is angled so that the light reflected from the first folding mirror 262A is projected onto a series of lenses and / or arrays 264 and through a projection lens 266 (not shown) of the optical engine 210. The series of lenses and / or arrays 264 may include a diffuser 272 and a reticle 274.

[0027]

[0031] The folding mirrors 262A and 262B fold the optical path of the light emitted by the light source 260, shortening the distance between the optical engine 210 and the reflection detector 212, thereby creating space for positioning the reflection detector 212 on the third grid 104c. Shortening the distance also allows for a reduction in the installation area of ​​the optical engine 210 and the reflection detector 212. The distance between the optical engine 210 and the reflection detector 212 may be about 10 millimeters (mm) to about 20 mm, for example, about 15 mm or less. The distance from the first end of the optical engine 210 away from the reflection detector 212 to the second end of the reflection detector 212 away from the optical engine 210 may be about 30 mm to about 70 mm, for example, about 50 mm.

[0028]

[0032] Overall, a compact measurement system and measurement method utilizing mirror-folding illumination for measuring multiple indicators is shown and described herein. By folding the illumination optical system, one or more folding mirrors are used to reduce the distance between the optical engine and the reflective detector of the measurement system, resulting in a more compact measurement system.

[0029]

[0033] While the above applies to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from its basic scope, which is determined by the following claims.

Claims

1. An optical device measurement system, A stage configured to move trays along a stage path, In order to enable the stage to move through the first opening and the second opening, a body having the first opening and the second opening, An optical engine positioned within the main body and mounted above the stage, configured to direct light rays toward the stage, light source, A folding mirror is angled relative to the light source and configured to change the direction of the light rays toward the stage. One or more lenses or arrays positioned between the folding mirror and the stage along the optical path, and A projection lens positioned between the one or more lenses or array and the stage along the optical path. Equipped with a light engine, A first detector is located within the main body and mounted above the stage adjacent to the optical engine, configured to receive projected light rays projected upward from the stage. An optical device measurement system equipped with the following features.

2. The optical device measurement system according to claim 1, wherein the light source of the optical engine is located on the side of the optical engine opposite to the first detector.

3. The optical device measurement system according to claim 1, wherein the first detector comprises a camera and a camera lens positioned between the camera and the stage path.

4. The optical device measurement system according to claim 1, wherein the folding mirror is angled from approximately 30 degrees to approximately 70 degrees.

5. The optical device measurement system according to claim 1, wherein the distance between the optical engine and the first detector is approximately 15 mm.

6. The optical device measurement system according to claim 1, wherein the distance from the first end of the optical engine away from the first detector to the second end of the first detector away from the optical engine is approximately 50 mm.

7. The optical device measurement system according to claim 1, further comprising a second detector positioned within the main body and mounted below the stage path, configured to receive a second projected ray projected downward from the stage.

8. The system further comprises a controller that communicates with the stage, the optical engine, and the first detector, and the controller, when an instruction is executed, The optical device measurement system according to claim 1, comprising a command for determining one or more indicators of an optical device, including one or more of the following: angular uniformity indicator, contrast indicator, efficiency indicator, color uniformity indicator, modulation transfer function (MTF) indicator, field of view (FOV) indicator, ghost image indicator, or eyebox indicator.

9. An optical device measurement system, A stage configured to move trays along a stage path, In order to enable the stage to move through the first opening and the second opening, a body having the first opening and the second opening, An optical engine positioned within the main body and mounted above the stage, configured to direct light rays toward the stage, light source, A first folding mirror angled with respect to the light source, A second folding mirror opposite to the first folding mirror, configured to change the direction of the light rays toward the stage, One or more lenses or arrays positioned between the second folding mirror and the stage along the optical path, and A projection lens positioned between the one or more lenses or array and the stage along the optical path. Equipped with a light engine, A first detector is located within the main body and mounted above the stage adjacent to the optical engine, configured to receive projected light rays projected upward from the stage. An optical device measurement system equipped with the following features.

10. The optical device measurement system according to claim 9, wherein the light source of the optical engine is positioned above the first folding mirror.

11. The optical device measurement system according to claim 9, wherein the first detector comprises a camera and a camera lens positioned between the camera and the stage.

12. The optical device measurement system according to claim 9, wherein the one or more lenses or arrays comprise a diffuser and a reticle.

13. The optical device measurement system according to claim 9, wherein the distance between the optical engine and the first detector is approximately 15 mm.

14. The optical device measurement system according to claim 9, wherein the distance from the first end of the optical engine away from the first detector to the second end of the first detector away from the optical engine is approximately 50 mm.

15. The optical device measurement system according to claim 9, further comprising a second detector positioned within the main body and mounted below the stage path, configured to receive a second projected ray projected downward from the stage path.

16. The system further comprises a controller that communicates with the stage, the optical engine, and the first detector, and the controller, when an instruction is executed, The optical device measurement system according to claim 9, comprising a command to determine one or more indicators of an optical device, including one or more of the following: angular uniformity indicator, contrast indicator, efficiency indicator, color uniformity indicator, modulation transfer function (MTF) indicator, field of view (FOV) indicator, ghost image indicator, or eyebox indicator.

17. A method for analyzing optical devices, Positioning optical devices within the measurement system, This involves directing a ray of light from the optical engine towards the optical device, and directing the ray of light is Projecting the light ray from the light source of the light engine onto the first folding mirror, To change the direction of the light ray toward the optical device, and Projecting the light ray onto one or more lenses or arrays, and projecting it towards the optical device through the projection lens. Including directing a ray of light, Using a first detector, capture multiple first images of the projected light beam projected from the optical device, To determine a plurality of first indicators of the optical device, one or more of the plurality of first images are processed. Methods that include...

18. The method according to claim 17, further comprising reflecting the light rays from the first folding mirror toward the second folding mirror.

19. The method according to claim 17, wherein the plurality of first indicators include one or more of the following: an angular uniformity indicator, a contrast indicator, an efficiency indicator, a color uniformity indicator, a modulation transfer function (MTF) indicator, a field of view (FOV) indicator, a ghost image indicator, or an eyebox indicator.

20. The method according to claim 17, wherein the distance between the optical engine and the first detector is approximately 15 mm.

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