TW202314306A - Selective deposition/patterning for layered waveguide fabrication - Google Patents

Abstract

Layered waveguides, multi-layer waveguide displays with layered waveguides, and methods of fabricating layered waveguides with selective bonding material deposition and/or patterning.

Description

Selective deposition or patterning for layered waveguide fabrication

The present invention relates to a selective deposition or patterning for the fabrication of layered waveguides. Related applications

This application asserts U.S. Provisional Application No. 1 filed on August 6, 2021 and entitled "SELECTIVE OPTICAL ADHESIVE DEPOSITION/PATTERNING FOR LAYERED WAVEGUIDE FABRICATION" 63/230,532, and U.S. Nonprovisional Patent Application No. 17/815,944, filed July 29, 2022, which are hereby incorporated by reference in their entirety for all purposes.

Artificial reality systems such as head-mounted display (HMD) or heads-up display (HUD) systems generally include devices configured to be used in front of a user's eyes via an electronic or optical display. or near-eye displays (for example, in the form of headphones or a pair of glasses) that present content. Near-eye displays can present virtual objects or combine images of real objects with virtual objects, such as in virtual reality (VR), augmented reality (augmented reality, AR) or mixed reality (mixed reality, MR) applications middle. For example, in an AR system, a user can see virtual objects (such as computer-generated images (CGI)) and their surroundings through, for example, see-through transparent display glass or lenses (commonly referred to as optical see-through). The image of both the environment.

One example of an optical see-through AR system may use a waveguide-based optical display, where light of a projected image may be coupled into a waveguide (eg, a transparent substrate), propagate within the waveguide, and then be coupled out of the waveguide at various locations. In some optical see-through AR systems, the light of the projected image may be coupled into or out of the waveguide using a diffractive optical element, such as a surface relief grating or a holographic grating. Light from the surrounding environment can also pass through the diffractive optical element in the see-through region of the waveguide and reach the user's eyes.

The present invention generally relates to multilayer waveguides, multilayer waveguide displays, and methods of making multilayer waveguides and displays thereof. Various inventive embodiments are described herein, including devices, systems, methods, materials, and the like.

Certain aspects are directed to a method of making one or more multilayer waveguides. The method includes receiving or forming a first waveguide layer and forming a bonding layer (eg, a layer of optically clear adhesive material) having one or more cut channels on the first waveguide layer. The method also includes forming a bonded waveguide stack by: bonding the second waveguide layer to the first waveguide layer; and cutting through the bonded waveguide stack along one or more cutting channels to form one or more multilayer waveguides. Additionally, the method includes forming one or more multilayer waveguide displays using the one or more multilayer waveguides.

Certain aspects are directed to a method of fabricating one or more multilayer waveguide displays. The method includes receiving or forming a first waveguide layer having one or more gratings (eg, input and/or output gratings). The method also includes forming a layer of optically clear adhesive material having one or more cut channels on the first waveguide layer. The method also includes forming a bonded waveguide stack by: bonding the second waveguide layer to the first waveguide layer; and cutting through the bonded waveguide stack along one or more cutting channels to form one or more multilayer waveguide displays. The method also includes forming one or more multilayer waveguide displays using the one or more multilayer waveguides.

Certain aspects are directed to a method of making one or more multilayer waveguides. The method includes receiving or forming a first waveguide layer and depositing a sacrificial material on the first waveguide layer along one or more dicing channels. The method also includes depositing an optically clear adhesive material in a region within the interior perimeter formed by the one or more dicing channels, forming a bonded waveguide stack by bonding the second waveguide layer to the first waveguide layer, and One or more dicing channels are cut through the bonded waveguide stack through the sacrificial material to form one or more multilayer waveguides.

Certain aspects are directed to multilayer waveguides fabricated by: receiving or forming a first waveguide layer; depositing sacrificial material on the first waveguide layer along one or more dicing channels; Depositing an optically clear adhesive material in a region within the inner perimeter formed by the channel; forming a bonded waveguide by bonding the second waveguide layer to the first waveguide layer; and cutting along one or more dicing channels through the sacrificial material The bonded waveguides are stacked to form one or more multilayer waveguides.

Certain aspects are directed to a multilayer waveguide display fabricated by receiving or forming a first waveguide layer with one or more gratings, and forming an optical waveguide layer with one or more dicing channels on the first waveguide layer. Layer of transparent adhesive material. A second waveguide layer is bonded to the first waveguide layer to form a waveguide stack, and the bonded waveguide stack is cut along one or more dicing channels to form one or more multilayer waveguides. A multilayer waveguide display is formed using one or more multilayer waveguides.

Certain aspects are directed to a multilayer waveguide display comprising a layered waveguide and one or more grating couplers configured to diffractively couple display light into or out of the layered waveguide And/or refract and transmit ambient light through the layered waveguide. A layered waveguide is fabricated by cutting through the bonded waveguide stack along one or more dicing channels in at least one of the plurality of waveguide layers of the bonded waveguide stack, wherein one or more dicing channels are free of bonding material ( such as adhesive materials).

Certain aspects are directed to one or more multilayer waveguides fabricated by receiving or forming a first waveguide layer, and forming a layer of optically clear adhesive material on the first waveguide layer. The layer of optically clear adhesive material has one or more cut channels free of optically clear adhesive material. The one or more multilayer waveguides are further fabricated by bonding the second waveguide layer to the first waveguide layer to form a waveguide stack, and cutting through the bonded waveguide stack along one or more dicing channels to form the one or more multilayer waveguides .

Certain aspects are directed to a method of making one or more multilayer waveguides. The method includes receiving or forming a first waveguide layer and depositing a sacrificial material in one or more regions on the first waveguide layer along one or more dicing channels. The method also includes depositing a bonding material at least partially within an interior perimeter of the one or more regions with a sacrificial material, and bonding the second waveguide layer to the first waveguide layer with the bonding material to form a bonded waveguide stack. Additionally, the method includes cutting through the bonded waveguide stack along one or more cutting channels to form one or more multilayer waveguides.

This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to this disclosure, in appropriate portions, of the entire specification, any or all drawings and respective claims. The foregoing, along with other features and examples, will be described in more detail below in the following specification, claims, and accompanying drawings.

In the following description, for purposes of explanation, specific details are set forth in order to provide a thorough understanding of certain inventive embodiments. It is evident, however, that various embodiments may be practiced without these specific details. The drawings and descriptions are not intended to be limiting.

The techniques disclosed herein relate generally to artificial reality display systems. More particularly, and without limitation, disclosed herein are layered waveguides for augmented or mixed reality and displays thereof, systems and methods for fabricating layered waveguides using selective optical adhesive deposition and/or patterning .

In an optical see-through waveguide display system, display light may be coupled into the waveguide by an input coupler, and then coupled out of the waveguide by an output coupler (eg, a grating coupler) towards the user's eye. The waveguide and coupler can be transparent to visible light, allowing a user to observe the surrounding environment through the waveguide display. Due to the different angles of diffraction of display light from different fields of view or colors, display light from different fields of view or colors may not be uniformly coupled out of the waveguide towards the user's eyes.

According to some embodiments, layered waveguides can be used to improve the uniformity of display light from different fields of view or different colors. A layered waveguide may include multiple waveguide layers with selected refractive indices and thicknesses.

In some examples, methods of fabricating layered waveguides use a dicing process that performs laser ablation, or the like, to cut through the bonded layered waveguide stack to singulate individual waveguides. Laser ablation operations may include using a high powered laser to iteratively remove material in areas to scratch through the layered waveguide stack. If optically-clear adhesive (OCA) or other bonding material is present at the edge of the waveguide die during the dicing operation, laser ablation or other similarly destructive process can reduce the adhesive material at the edge of individual waveguides of joint strength. Certain bonding processes can generate residual stress in the adhesive material layer due to, for example, polymerization shrinkage from ultraviolet (UV) curing or from thermal bonding layers with mismatched coefficients of thermal expansion (CTE). In some cases, to relieve residual stress in the bonding layer, delamination beginning at the edge of the waveguide (where the bonding strength of the adhesive material may have been reduced during the dicing process) may propagate inwards over time such that The waveguide layer is layered.

In certain implementations, methods of fabricating layered waveguides remove or avoid the formation of adhesive or other bonding material in one or more dicing channels in a bonded waveguide stack where dicing occurs. In this way, the properties of the bonding layer may not be affected by the dicing process, and delamination due to reduced bonding strength due to laser ablation or similar processes may be avoided.

In certain implementations, the method of fabricating a layered waveguide forms sacrificial material in one or more dicing lines. The sacrificial material may be formed prior to depositing the adhesive material to form barriers within which the adhesive material may be deposited by, for example, a drop casting process or an inkjet process. Alternatively, the sacrificial material may be formed in one or more cut channels formed in the bonding material.

In the following description, for purposes of explanation, specific details are set forth in order to provide a thorough understanding of examples of the present disclosure. It may be evident, however, that various examples may be practiced without these specific details. For example, devices, systems, structures, assemblies, methods, and other components may be shown as components in block diagram form in order not to obscure the examples with unnecessary detail. In other instances, well-known devices, processes, systems, structures and techniques may be shown without unnecessary detail in order not to obscure the examples. The drawings and descriptions are not intended to be limiting. The terms and expressions that have been used in this disclosure are terms of description and not of limitation, and in the use of such terms and expressions it is not intended to exclude any equivalents or parts of the features shown and described. The word "example" is used herein to mean "serving as an instance, instance, or illustration." Any particular example or design described herein as an "example" is not necessarily to be construed as being better than or superior to other particular examples or designs.

1 is a simplified block diagram of an example of an artificial reality system environment 100 including a near- eye display 120 according to certain embodiments. The artificial reality system environment 100 shown in FIG. 1 may include a near-eye display 120 , an optional external imaging device 150 , and an optional input/output interface 140 , each of which may be coupled to an optional console 110 . Although FIG. 1 shows an example of an AR system environment 100 including a near-eye display 120 , an external imaging device 150 , and an input/output interface 140 , any number of these components may be included in the AR system environment 100 , Or any of these components may be omitted. For example, there may be multiple near-eye displays 120 that may be monitored by one or more external imaging devices 150 in communication with console 110 . In some configurations, the augmented reality environment 100 may not include the external imaging device 150 , the optional input/output interface 140 , and the optional console 110 . In alternative configurations, different or additional components may be included in the augmented reality system environment 100 .

The near-eye display 120 may be a head-mounted display that presents content to the user. Examples of content presented by the near-eye display 120 include one or more of images, video, audio, or any combination thereof. In some embodiments, the audio is presented via an external device (e.g., speakers and/or headphones) that receives audio information from near-eye display 120 , console 110 , or both, and presents the audio based on the audio information material. The near-eye display 120 may include one or more rigid bodies that may be rigidly or non-rigidly coupled to each other. Rigid couplings between rigid bodies may cause the coupled rigid bodies to act as a single rigid entity. A non-rigid coupling between rigid bodies allows the rigid bodies to move relative to each other. In various embodiments, near-eye display 120 may be implemented in any suitable form factor, including a pair of eyeglasses. Some specific examples of near-eye display 120 are described further below with respect to FIGS. 2 and 3 . Additionally, in various embodiments, the functionality described herein may be used in headsets that combine images of the environment external to near-eye display 120 with artificial reality content (eg, computer-generated images). Therefore, the near-eye display 120 can amplify the image of the physical real-world environment outside the near-eye display 120 through the generated content (eg, image, video, sound, etc.), so as to present the augmented reality to the user.

In various embodiments, the near-eye display 120 may include one or more of the display electronics 122 , the display optics 124 , and the eye-tracking unit 130 . In some specific examples, the near-eye display 120 may also include one or more positioners 126 , one or more position sensors 128 and an inertial measurement unit (IMU) 132 . In various embodiments, the near-eye display 120 may omit any of the eye-tracking unit 130 , the locator 126 , the position sensor 128 , and the IMU 132 , or include additional elements. Additionally, in some embodiments, near-eye display 120 may include elements that combine the functionality of the various elements described in FIG. 1 .

Display electronics 122 may display images to a user or facilitate displaying images to a user based on data received from, for example, console 110 . In various specific examples, the display electronics 122 may include one or more display panels, such as a liquid crystal display (liquid crystal display; LCD), an organic light emitting diode (organic light emitting diode; OLED) display, an inorganic light emitting diode (inorganic light emitting diode; ILED) display, micro light emitting diode (micro light emitting diode; μLED) display, active-matrix OLED display (active-matrix OLED display; AMOLED), transparent OLED display (transparent OLED display; TOLED) or some other display. For example, in one implementation of near-eye display 120 , display electronics 122 may include a front TOLED panel, a rear display panel, and optical components between the front and rear display panels (e.g., attenuators, polarizers, or diffraction or spectral film). Display electronics 122 may include pixels to emit light of a primary color such as red, green, blue, white or yellow. In some implementations, the display electronics 122 can display a three-dimensional (3-dimensional; 3D) image through the stereoscopic effect generated by the two-dimensional panel to generate a subjective perception of image depth. For example, the display electronics 122 may include left and right displays located in front of the user's left and right eyes, respectively. The left and right displays may present copies of the image that are shifted horizontally relative to each other to create a stereoscopic effect (ie, the user viewing the image's perception of depth).

In some embodiments, display optics 124 may display image content optically (e.g., using optical waveguides and couplers), or amplify image light received from display electronics 122 , correcting optical errors associated with image light , and present the corrected image light to the user of the near-eye display 120 . In various embodiments, display optics 124 may include one or more optical elements, such as substrates, optical waveguides, apertures, Fresnel lenses, convex lenses, concave lenses, filters, input/output couplers, Or any other suitable optical element that may affect the image light emitted from the display electronics 122 . Display optics 124 may include a combination of different optical elements, and mechanical couplers to maintain the relative spacing and orientation of the optical elements in the combination. One or more optical elements in display optics 124 may have an optical coating, such as an anti-reflective coating, a reflective coating, a filter coating, or a combination of different optical coatings.

Amplification of image light by display optics 124 may allow display electronics 122 to be physically smaller, weigh less and consume less power than larger displays. Additionally, zooming in increases the field of view of the displayed content. The amount of magnification of image light by display optics 124 can be varied by adjusting, adding optics 124 , or removing optical elements from display optics 124 . In some embodiments, display optics 124 may project the displayed image to one or more image planes that may be farther away from the user's eyes than near-eye display 120 .

Display optics 124 may also be designed to correct for one or more types of optical errors, such as two-dimensional optical errors, three-dimensional optical errors, or any combination thereof. Two-dimensional errors may include optical aberrations that occur in two dimensions. Example types of two-dimensional errors may include barrel distortion, pincushion distortion, longitudinal chromatic aberration, and lateral chromatic aberration. Three-dimensional errors may include optical errors that occur in three dimensions. Example types of three-dimensional errors may include spherical aberration, coma, field curvature, and astigmatism.

Locators 126 may be objects positioned in particular locations on near-eye display 120 relative to each other and relative to a reference point on near-eye display 120 . In some implementations, the console 110 can identify the locator 126 in images captured by the external imaging device 150 to determine the location, orientation, or both of the artificial reality headset. Locators 126 may be light emitting diodes (LEDs), right angle reflectors, reflective markers, a type of light source that contrasts with the environment in which near-eye display 120 operates, or any combination thereof. In embodiments where the locator 126 is an active component such as an LED or other type of light emitting device, the locator 126 may emit infrared (IR) light in the visible light band (eg, approximately 380 nm to 750 nm). Light in the frequency band (eg, about 750 nm to 1 mm), in the ultraviolet band (eg, about 10 nm to about 380 nm), in another part of the electromagnetic spectrum, or any combination of parts of the electromagnetic spectrum.

External imaging device 150 may include one or more cameras, one or more video cameras, any other device capable of capturing images including one or more of locators 126 , or any combination thereof. Additionally, external imaging device 150 may include one or more filters (eg, to increase the signal-to-noise ratio). External imaging device 150 may be configured to detect light emitted or reflected from locator 126 in the field of view of external imaging device 150 . In embodiments where locators 126 include passive elements (e.g., retroreflectors), external imaging device 150 may include a light source that illuminates some or all of locators 126 that reflect light back into The light source in the external imaging device 150 . Slow calibration data can be communicated from the external imaging device 150 to the console 110 , and the external imaging device 150 can receive one or more calibration parameters from the console 110 to adjust one or more imaging parameters (e.g., focal length, focus, frame rate , sensor temperature, shutter speed, aperture, etc.).

The position sensor 128 can generate one or more measurement signals in response to the movement of the near-eye display 120 . Examples of position sensors 128 may include accelerometers, gyroscopes, magnetometers, other motion detection or error correction sensors, or any combination thereof. For example, in some embodiments, position sensor 128 may include multiple accelerometers to measure translation (eg, forward/backward, up/down, or left/right) and to measure rotation Multiple gyroscopes for motion such as pitch, yaw or roll. In some specific examples, the various position sensors may be oriented orthogonally to one another.

IMU 132 may be an electronic device that generates rapid calibration data based on measurement signals received from one or more of position sensors 128 . Position sensor 128 may be positioned external to IMU 132 , internal to IMU 132 , or any combination thereof. Based on one or more measurement signals from one or more position sensors 128 , IMU 132 may generate quick calibration data indicating an estimated position of near-eye display 120 relative to an initial position of near-eye display 120 . For example, IMU 132 may integrate measurements received from accelerometers over time to estimate a velocity vector, and integrate the velocity vector over time to determine an estimated location of a reference point on near-eye display 120 . Alternatively , IMU 132 may provide sampled measurement signals to console 110 , which may determine quick calibration data. While a reference point can generally be defined as a point in space, in various embodiments, a reference point can also be defined as a point within near-eye display 120 (eg, the center of IMU 132 ).

The eye tracking unit 130 may include one or more eye tracking systems. Eye tracking may refer to determining the position of the eye relative to the near-eye display 120 , including the orientation and position of the eye. An eye tracking system may include an imaging system to image one or more eyes, and optionally include a light emitter that generates light that is directed to the eye so that light reflected by the eye can be picked up by the imaging system . For example, the eye tracking unit 130 may include an incoherent or coherent light source (eg, a laser diode) that emits light in the visible or infrared spectrum, and a camera that captures the light reflected by the user's eyes . As another example, eye tracking unit 130 may capture reflected radio waves emitted by a miniature radar unit. The eye tracking unit 130 may use low power light emitters that emit light at frequencies and intensities that will not damage the eyes or cause physical discomfort. Eye-tracking unit 130 may be configured to increase the contrast of eye images captured by eye-tracking unit 130 while reducing the overall power consumed by eye-tracking unit 130 (e.g., reducing power consumed by the optical transmitter and imaging system). For example, in some implementations, eye tracking unit 130 may consume less than 100 milliwatts of power.

The near-eye display 120 may use the orientation of the eyes to, for example, determine the user's inter-pupillary distance (IPD), determine gaze direction, introduce depth cues (e.g., blurry images outside the user's primary line of sight), collect Heuristic information about user interactions in VR media (e.g., time spent on any particular entity, object, or frame, which varies depending on the stimulus to which it is exposed) is based in part on at least one of the user's eyes. some other function of orientation, or any combination thereof. Since the orientation of the user's two eyes can be determined, the eye tracking unit 130 may be able to determine where the user is looking. For example, determining the gaze direction of the user may include determining a point of convergence based on the determined orientations of the user's left and right eyes. The point of convergence may be the point where two foveal axes of the user's eyes intersect. The user's gaze direction may be a line and direction passing through the point of convergence and the midpoint between the pupils of the user's eyes.

The input/output interface 140 may be a device that allows a user to send action requests to the console 110 . An action request may be a request to perform a specific action. For example, an action request may start or end an application or perform a specific action within an application. The input/output interface 140 may include one or more input devices. Example input devices may include a keyboard, mouse, game controller, glove, buttons, touch screen, or any other suitable device for receiving motion requests and communicating the received motion requests to console 110 . Action requests received by input/output interface 140 may be communicated to console 110 where actions corresponding to the requested actions may be performed. In some embodiments, the input/output interface 140 can provide tactile feedback to the user according to commands received from the console 110 . For example, the input/output interface 140 may provide haptic feedback when an action request is received or when the console 110 has performed the requested action and communicated the instruction to the input/output interface 140 . In some embodiments, the external imaging device 150 can be used to track the input/output interface 140 , such as tracking the position or position of the controller (which may include, for example, an IR light source) or the user's hand to determine the user's motion. In some embodiments, the near-eye display 120 may include one or more imaging devices to track the input/output interface 140 , such as tracking the position or position of a controller or a user's hand to determine the user's motion.

The console 110 may provide content to the near-eye display 120 for presentation to the user based on information received from one or more of the external imaging device 150 , the near-eye display 120 , and the input/output interface 140 . In the example shown in FIG. 1 , the console 110 may include an app store 112 , a headset tracking module 114 , an artificial reality engine 116 , and an eye tracking module 118 . Some embodiments of the console 110 may include different or additional modules than those described in conjunction with FIG. 1 . The functionality described further below may be distributed among the components of console 110 in different ways than described here.

In some embodiments, console 110 may include a processor and a non-transitory computer-readable storage medium storing instructions executable by the processor. A processor may include multiple processing units that execute instructions in parallel. A non-transitory computer-readable storage medium can be any memory such as a hard drive, removable memory, or solid-state drive (eg, flash memory or dynamic random access memory (DRAM)) body. In various embodiments, the modules that interface with the console 110 described in FIG. 1 can be encoded as instructions in a non-transitory computer-readable storage medium that, when executed by the processor, cause the processor to proceed further below. function described.

The application store 112 can store one or more application programs for the console 110 to execute. An application may include a set of instructions that, when executed by a processor, generate content for presentation to a user. The content generated by the application may be input received from the user in response to movement of the user's eyes, or input received from the input/output interface 140 . Examples of applications may include: gaming applications, conferencing applications, video playback applications, or other suitable applications.

The headphone tracking module 114 can use the slow calibration information from the external imaging device 150 to track the movement of the near-eye display 120 . For example, the headset tracking module 114 may use observed locators from the slow calibration information and a model of the near-eye display 120 to determine the location of a reference point for the near-eye display 120 . The headset tracking module 114 can also use the location information from the quick calibration information to determine the location of the reference point of the near-eye display 120 . Additionally, in some embodiments, the headset tracking module 114 may use portions of the fast calibration information, the slow calibration information, or any combination thereof to predict the future location of the near-eye display 120 . The headset tracking module 114 may provide the estimated location or the predicted future location of the near-eye display 120 to the artificial reality engine 116 .

The artificial reality engine 116 can execute the application program in the artificial reality system environment 100 , and receive the position information of the near-eye display 120 , the acceleration information of the near-eye display 120 , the speed information of the near-eye display 120 , and the near-eye display 120 from the headset tracking module 114. its predicted future location, or any combination thereof. The artificial reality engine 116 may also receive estimated eye position and orientation information from the eye tracking module 118 . Based on the received information, the artificial reality engine 116 may determine content to provide to the near-eye display 120 for presentation to the user. For example, if the received information indicates that the user has looked to the left, the artificial reality engine 116 may generate content for the near-eye display 120 that reflects the movement of the user's eyes in the virtual environment. In addition, the augmented reality engine 116 may take an action within an application executing on the console 110 in response to an action request received from the input/output interface 140 and provide feedback to the user indicating that the action has been taken. The feedback can be visual or auditory feedback via the near-eye display 120 , or tactile feedback via the input/output interface 140 .

The eye-tracking module 118 can receive eye-tracking data from the eye-tracking unit 130 and determine the position of the user's eyes based on the eye-tracking data. The location of the eye may include the orientation, location, or both of the eye relative to the near-eye display 120 or any element thereof. Since the rotational axis of the eye changes depending on the position of the eye in its socket, determining the position of the eye in its socket may allow the eye tracking module 118 to more accurately determine the orientation of the eye.

2 is a perspective view of an example of a near - eye display in the form of an HMD device 200 for implementing some of the examples disclosed herein. The HMD device 200 may be part of, for example, a VR system, an AR system, an MR system, or any combination thereof. The HMD device 200 may include a main body 220 and a head strap 230 . FIG. 2 shows the bottom side 223, the front side 225 , and the left side 227 of the main body 220 in perspective view. The head strap 230 may have an adjustable or extendable length. There may be sufficient space between the main body 220 of the HMD device 200 and the head strap 230 to allow the user to mount the HMD device 200 on the user's head. In various embodiments, HMD device 200 may include additional components, fewer components, or different components. For example, instead of head strap 230, in some embodiments, HMD device 200 may include eyeglass temples and temple tips, as shown, for example, in FIG. 3 below.

HMD device 200 may present media to a user that includes virtual and/or augmented views of a physical real-world environment with computer-generated elements. Examples of media presented by HMD device 200 may include images (eg, two-dimensional (2D) or three-dimensional (3D) images), video (eg, 2D or 3D video), audio, or any combination thereof. These images and videos can be presented to the user's eyes by one or more display assemblies (not shown in FIG. 2 ) enclosed in the main body 220 of the HMD device 200 . In various embodiments, one or more display assemblies may include a single electronic display panel or multiple electronic display panels (eg, one display panel for each eye of a user). Examples of electronic display panels may include, for example, LCDs, OLED displays, ILED displays, μLED displays, AMOLEDs, TOLEDs, some other display, or any combination thereof. The HMD device 200 may include two eye frame regions.

In some implementations, the HMD device 200 may include various sensors (not shown in the figure), such as a depth sensor, a motion sensor, a position sensor, and an eye tracking sensor. Some of these sensors can use structured light patterns for sensing. In some implementations, the HMD device 200 can include an input/output interface for communicating with a console. In some implementations, the HMD device 200 may include a virtual reality engine (not shown in the figure), the virtual reality engine may execute the application program in the HMD device 200 , and receive depth information of the HMD device 200 from various sensors, Location information, acceleration information, velocity information, predicted future location, or any combination thereof. In some implementations, information received by the virtual reality engine may be used to generate signals (eg, display commands) for one or more display assemblies. In some implementations, the HMD device 200 may include locators (not shown, such as locators 126 ) positioned in fixed positions on the body 220 relative to each other and relative to a reference point. Each of the locators can emit light that can be detected by an external imaging device.

3 is a perspective view of an example of a near - eye display 300 in the form of a pair of glasses for implementing some of the examples disclosed herein. Near-eye display 300 may be a particular implementation of near-eye display 120 of FIG. 1 and may be configured to operate as a virtual reality display, an augmented reality display, and/or a mixed reality display. The near-eye display 300 includes a frame 305 and a display 310 . Display 310 can be configured to present content to a user. In some embodiments, display 310 may include display electronics and/or display optics. For example, as described above with respect to near-eye display 120 of FIG. 1 , display 310 may include an LCD display panel, an LED display panel, or an optical display panel (eg, a waveguide display assembly).

The near-eye display 300 may further include various sensors 350a , 350b , 350c , 350d , and 350e on or within the frame 305 . In some embodiments, the sensors 350a - 350e may include one or more depth sensors, motion sensors, position sensors, inertial sensors, or ambient light sensors. In some embodiments, the sensors 350a - 350e may include one or more image sensors configured to generate image data representing different fields of view in different directions. In some embodiments, the sensors 350a - 350e can be used as input devices to control or affect the displayed content of the near-eye display 300 , and/or provide an interactive VR/AR/MR experience to the user of the near-eye display 300 . In some embodiments, the sensors 350a - 350e can also be used for stereoscopic imaging.

In some embodiments, the near-eye display 300 may further include one or more illuminators 330 to project light into the physical environment. The projected light can be associated with different frequency bands (eg, visible, infrared, ultraviolet, etc.) and can be used for various purposes. For example, the illuminator 330 can project light into a dark environment (or an environment with low intensity infrared light, ultraviolet light, etc.) to assist the sensors 350a to 350e in capturing images of different objects in the dark environment . In some embodiments, illuminators 330 may be used to project certain light patterns onto objects within the environment. In some embodiments, illuminator 330 may be used as a locator, such as locator 126 described above with respect to FIG. 1 .

In some specific examples, the near-eye display 300 may also include a high-resolution camera 340 . The camera 340 can capture images of the physical environment in the field of view. The captured image can be processed, for example, by a virtual reality engine (e.g., artificial reality engine 116 of FIG. 1 ) to add virtual objects to the captured image or to modify physical objects in the captured image, and the processed image Can be displayed to the user by the display 310 for AR or MR applications.

4 illustrates an example of an optical see-through augmented reality system 400 including a waveguide display , according to certain embodiments. The augmented reality system 400 may include a projector 410 and a combiner 415 . Projector 410 may include a light source or image source 412 and projector optics 414 . In some embodiments, the light source or image source 412 may include one or more micro LED devices described above. In some embodiments, the image source 412 may include a plurality of pixels for displaying virtual objects, such as an LCD display panel or an LED display panel. In some embodiments, image source 412 may include a light source that produces coherent or partially coherent light. For example, the image source 412 may include a laser diode, a vertical cavity surface-emitting laser, an LED, and/or a micro-LED as described above. In some embodiments, image source 412 may include a plurality of light sources (eg, the micro LED arrays described above) each emitting monochromatic image light corresponding to a primary color (eg, red, green, or blue). In some embodiments, image source 412 can include three two-dimensional arrays of micro-LEDs, where each two-dimensional array of micro-LEDs can include LEDs configured to emit light having a primary color (eg, red, green, or blue). Micro LEDs. In some embodiments, image source 412 may include an optical pattern generator, such as a spatial light modulator. Projector optics 414 may include one or more optical components that can condition light from image source 412 , such as expand, collimate, scan, or project light from image source 412 to combiner 415 . The one or more optical components may include, for example, one or more lenses, liquid lenses, mirrors, apertures and/or gratings. For example, in some embodiments, image source 412 can include one or more one-dimensional arrays of micro-LEDs or an array of elongated two-dimensional micro-LEDs, and projector optics 414 can include arrays of micro-LEDs configured to scan one-dimensional arrays of micro-LEDs. Or elongated two-dimensional micro-LED arrays to produce one or more one-dimensional scanners (eg, micromirrors or micromirrors) for image frames. In some embodiments, projector optics 414 may include a liquid lens (eg, a liquid crystal lens) having a plurality of electrodes that allows light from image source 412 to be scanned.

The combiner 415 may include an input coupler 430 for coupling light from the projector 410 into the substrate 420 of the combiner 415 . The combiner 415 can transmit at least 50% of the light in the first wavelength range and reflect at least 25% of the light in the second wavelength range. For example, the first wavelength range may be visible light from about 400 nm to about 650 nm, and the second wavelength range may be in the infrared band, eg, from about 800 nm to about 1000 nm. The input coupler 430 may include a volume holographic grating, a diffractive optical element (DOE) (eg, a surface relief grating), a sloped surface of the substrate 420 , or a refractive coupler (eg, a wedge or a dimple). For example, the input coupler 430 may comprise a reflective volume Bragg hologram or a transmissive volume Bragg hologram. For visible light, the input coupler 430 can have a coupling efficiency greater than 30%, 50%, 75%, 90%, or higher. The light coupled into the substrate 420 may propagate within the substrate 420 through, for example, total internal reflection (TIR). Substrate 420 may be in the form of a lens of a pair of eyeglasses. Substrate 420 may have a flat or curved surface, and may include one or more types of dielectric materials, such as glass, quartz, plastic, polymer, poly(methyl methacrylate) (PMMA), crystal or ceramic. The thickness of the substrate can range, for example, from less than about 1 mm to about 10 mm or more. The substrate 420 may be transparent to visible light.

Substrate 420 may include or be coupled to a plurality of output couplers 440 each configured to extract from substrate 420 at least a portion of the light guided by and propagating within substrate 420 and to extract the extracted The light 460 is directed to an eye window 495 where an eye 490 of a user of the augmented reality system 400 may be positioned when the augmented reality system 400 is in use. Multiple output couplers 440 can duplicate the exit pupil to increase the size of the human eye window 495 so that the displayed image is visible over a larger area. Like the input coupler 430 , the output coupler 440 may include a grating coupler (eg, a volume hologram or a surface relief grating), other diffractive optical elements, gratings, or the like. For example, the output coupler 440 may comprise a reflective volume Bragg hologram or a transmissive volume Bragg hologram. Output coupler 440 may have different coupling (eg, diffraction) efficiencies at different locations. Substrate 420 may also allow light 450 from the environment in front of combiner 415 to pass through with little or no loss. Output coupler 440 may also allow light 450 to pass through with very little loss. For example, in some implementations, output coupler 440 may have very low diffraction efficiency for light 450 such that light 450 may be refracted or otherwise pass through output coupler 440 with very little loss, and thus may have Higher than the intensity of the extracted light 460 . In some implementations, output coupler 440 can have high diffraction efficiency for light 450 and can diffract light 450 in certain desired directions (ie, diffraction angles) with very little loss. Thus, the user may be able to view the combined image of the environment in front of the combiner 415 and the image of the virtual object projected by the projector 410 .

5A illustrates an example of a near-eye display (NED) device 500 including a waveguide display 530 according to certain embodiments. NED device 510 may be an example of near-eye display 120 , augmented reality system 400 , or another type of display device. NED device 500 may include light source 510 , projection optics 520 and waveguide display 530 . Light source 510 may include multiple panels for light emitters of different colors, such as a panel of red light emitters 512 , a panel of green light emitters 514 , and a panel of blue light emitters 516 . Red emitters 512 are organized in an array; green emitters 514 are organized in an array; and blue emitters 516 are organized in an array. The size and spacing of the light emitters in light source 510 may be small. For example, each light emitter can have a diameter of less than 2 µm (eg, about 1.2 µm) and a pitch of less than 2 µm (eg, about 1.5 µm). Therefore, the number of light emitters in each of the red light emitter 512 , green light emitter 514 , and blue light emitter 516 can be equal to or greater than the number of pixels in the displayed image, such as 960× 720 , 1280× 720 , 1440×1080 , 1920×1080, 2160×1080, or 2560×1080 pixels. Therefore, display images can be generated by the light sources 510 simultaneously. Scanning elements may not be used in NED device 500 .

Before reaching waveguide display 530 , light emitted by light source 510 may be conditioned by projection optics 520 , which may include an array of lenses. Projection optics 520 may collimate or focus light emitted by light source 510 into waveguide display 530 , which may include coupler 532 for coupling light emitted by light source 510 into waveguide display 530 . Light coupled into waveguide display 530 may propagate within waveguide display 530 by, for example, total internal reflection as described above with respect to FIG. 4 . The coupler 532 may also couple a portion of the light propagating within the waveguide display 530 out of the waveguide display 530 and toward the user's eye 590 .

5B illustrates an example of a near - eye display (NED) device 550 including a waveguide display 580 according to certain embodiments. In some embodiments, NED device 550 may use scanning mirror 570 to project light from light source 540 to an image field in which user's eyes 590 may be positioned. NED device 550 may be an example of near-eye display 120 , augmented reality system 400 , or another type of display device. Light source 540 may include one or more columns or rows of light emitters of different colors, such as columns of red light emitters 542 , columns of green light emitters 544 , and columns of blue light emitters 546 . For example, red light emitter 542 , green light emitter 544 , and blue light emitter 546 may each include N columns, each column including, for example, 2560 light emitters (pixels). Red emitters 542 are organized in an array; green emitters 544 are organized in an array; and blue emitters 546 are organized in an array. In some embodiments, light source 540 may include a single row of light emitters for each color. In some embodiments, light source 540 can include multiple rows of light emitters for each of red, green, and blue, where each row can include, for example, 1080 light emitters. In some embodiments, the size and/or pitch of light emitters in light source 540 may be relatively large (e.g., about 3 to 5 μm), and thus light source 540 may not include enough light emitters to simultaneously generate a full display image . For example, the number of light emitters for a single color may be less than the number of pixels in a displayed image (eg, 2560x1080 pixels). The light emitted by light source 540 may be a collection of collimated or diverging beams.

Light emitted by light source 540 may be conditioned by various optical devices such as collimating lenses or freeform optics 560 before reaching scan mirror 570 . Free-form optical element 560 may comprise, for example, a faceted facet or another light-folding element that can direct light emitted by light source 540 to scanning mirror 570 , such as to direct light emitted by light source 540 The direction of propagation of the light changes, for example, by about 90° or more. In some embodiments, freeform optics 560 can be rotatable to allow light to scan. Scanning mirror 570 and/or freeform optics 560 may reflect and project light emitted by light source 540 onto waveguide display 580 , which may include coupler 582 for coupling light emitted by light source 540 into waveguide display 580 . Light coupled into waveguide display 580 may propagate within waveguide display 580 by, for example, total internal reflection as described above with respect to FIG. 4 . The coupler 582 may also couple a portion of the light propagating within the waveguide display 580 out of the waveguide display 580 and toward the user's eye 590 .

The scanning mirror 570 may include a microelectromechanical system (MEMS) mirror or any other suitable mirror. Scanning mirror 570 is rotatable to scan in one or two dimensions. As the scanning mirror 570 rotates, the light emitted by the light source 540 can be directed to different areas of the waveguide display 580 , so that the complete display image can be projected onto the waveguide display 580 and guided by the waveguide display 580 to use in each scanning cycle. The eyes of the hunter 590 . For example, in embodiments where light source 540 includes light emitters for all pixels in one or more columns or rows, scanning mirror 570 may be rotated in a row or column direction (eg, x or y direction) to scan an image. In embodiments where light source 540 includes light emitters for some but not all pixels in one or more columns or rows, scanning mirror 570 may be rotated in both column and row directions (e.g., both x and y directions) to Projecting a display image (for example, using a raster-type scan pattern).

The NED device 550 can operate in a predefined display period. A display period (eg, a display cycle) may refer to the duration for which a full image is scanned or projected. For example, the display period may be the inverse of the desired frame rate. In the NED device 550 including the scanning mirror 570 , the display period may also be referred to as a scanning period or a scanning cycle. The light generation by light source 540 may be synchronized with the rotation of scanning mirror 570 . For example, each scan cycle may include multiple scan steps, wherein the light source 540 may generate a different light pattern in each respective scan step.

During each scanning cycle, as the scanning mirror 570 rotates, a displayed image may be projected onto the waveguide display 580 and the user's eyes 590 . The actual color value and light intensity (eg, brightness) of a given pixel site displaying an image may be the average of the three colored (eg, red, green, and blue) light beams illuminating that pixel site during a scan period. After a scan cycle is complete, the scan mirror 570 may return to its original position to project the previous columns of light for the next displayed image, or may rotate in the reverse direction or in a scanning pattern to project the light of the next displayed image, with a new set of A driving signal may be fed to the light source 540 . The same process may be repeated as the scan mirror 570 rotates through each scan cycle. Thus, different images can be projected to the user's eye 590 in different scan cycles.

6A illustrates an example of an optical see-through augmented reality system including a waveguide display 600 for exit pupil expansion and a surface relief grating , according to certain embodiments. Waveguide display 600 may include substrate 610 (eg, a waveguide), which may be similar to substrate 420 . Substrate 610 may be transparent to visible light and may include, for example, glass, quartz, plastic, polymer, PMMA, ceramic, _{Si3N4 ,} or crystalline substrates. The substrate 610 may be a flat substrate or a curved substrate. The substrate 610 may include a first surface 612 and a second surface 614 . The display light can be coupled into the substrate 610 by the input coupler 620 and can be reflected by the first surface 612 and the second surface 614 by total internal reflection, so that the display light can propagate within the substrate 610 . The input coupler 620 may include a grating, a refractive coupler (eg, a wedge or a wedge), or a reflective coupler (eg, a reflective surface with an oblique angle relative to the substrate 610 ). For example, in one embodiment, the input coupler 620 may include a plenum that can couple display lights having different colors into the substrate 610 at the same refraction angle. In another example, the input coupler 620 can include a grating coupler that can diffract different colors of light into the substrate 610 in different directions. For visible light, the input coupler 620 may have a coupling efficiency greater than 10%, 20%, 30%, 50%, 75%, 90%, or greater.

The waveguide display 600 may also include a first output grating 630 and a second output grating 640 positioned on one or both surfaces of the substrate 610 (e.g., the first surface 612 and the second surface 614 ) for expanding in two dimensions The display light beam is incident to fill the human eye window with the display light. The first output grating 630 may be configured to expand at least a portion of the display light beam along one direction, such as generally in the x-direction. Display light coupled into substrate 610 may propagate in the direction shown by line 632 . Although the display light propagates within the substrate 610 in the direction shown by the line 632 , whenever the display light propagating within the substrate 610 reaches the first output grating 630 , a portion of the display light may be directed by the region of the first output grating 630 . The second output grating 640 diffracts, as shown by line 634 . Whenever the display light propagating within the substrate 610 reaches the second output grating 640 , the second output grating 640 can then distort the display light in different directions (e.g. , substantially in the y direction) to expand the display light from the first output grating 630 .

Figure 6B illustrates an example of an eye frame including a two-dimensionally replicated exit pupil. FIG. 6B shows that a single input pupil 605 can be replicated by a first output grating 630 and a second output grating 640 to form a converging exit pupil 660 comprising a two-dimensional array of individual exit pupils 662 . For example, the exit pupil may be replicated in the approximate x direction by the first output grating 630 and in the approximate y direction by the second output grating 640 . As described above, output light from individual exit pupils 662 traveling in the same direction can be focused onto the same location in the retina of the user's eye. Thus, a single image may be formed in the two-dimensional array of individual exit pupils 662 from the output light by the user's eye.

FIG. 7 illustrates an example of a tilted grating 720 in a waveguide display 700 according to certain embodiments. Slanted grating 720 may be an example of input coupler 430 , output coupler 440 or grating couplers 620 , 630 and 640 . The waveguide display 700 may include a tilted grating 720 on a waveguide 710 , such as the substrate 420 or the substrate 610 . Slanted grating 720 may act as a grating coupler for coupling light into or out of waveguide 710 . In some specific examples, the tilted grating 720 may include a one-dimensional periodic structure with a period p . For example, the tilted grating 720 may include a plurality of ridges 722 and grooves 724 between the ridges 722 . Each period of the tilted grating 720 may include ridges 722 and grooves 724 , which may be air gaps or regions filled with a material having a refractive index _ng2 . The ratio between the width d of the ridge 722 and the grating period p may be referred to as the duty cycle. Slanted grating 720 may have a duty cycle in the range of, for example, about 10% to about 90% or greater. In some specific examples, the duty cycle can vary between cycles. In some embodiments, the period p of the tilted grating can vary from region to region on the tilted grating 720 , or can vary from period to period (ie, chirped) across the tilted grating 720 .

Ridge 722 may be made of a material having a refractive index n _g1 , such as a silicon- _containing material (e.g., _SiO2 , _Si3N4 , SiC, _SiOxNy , or _amorphous silicon), an organic material (e.g., spin-on carbon (spin on carbon; SOC) or amorphous carbon layer (amorphous carbon layer; ACL) or masonry-like carbon (diamond like carbon; DLC)) or inorganic metal oxide layer (for example, TiO _x , AlO _x , TaO _x , HfO _x etc.). Each ridge 722 can include a leading edge 726 having an inclination angle α and a trailing edge 728 having an inclination angle β. In some embodiments, the leading edge 726 and the trailing edge 728 of each ridge 722 can be parallel to each other. In other words, the inclination angle α is substantially equal to the inclination angle β. In some embodiments, tilt angle α may be different than tilt angle β. In some embodiments, tilt angle α may be substantially equal to tilt angle β. For example, the difference between the tilt angle α and the tilt angle β may be less than 20%, 10%, 5%, 1% or less. In some embodiments, the tilt angle α and the tilt angle β may range, for example, from about 30° or less to about 70° or more.

In some implementations, the grooves 724 between the ridges 722 can be overcoated or filled with an overcoat 730 . Overcoat 730 may include a material having a refractive index _ng2 that is higher or lower than that of the material of ridge 722 . For example, in some embodiments, high-index materials such as hafnium oxide, titanium dioxide, tantalum oxide, tungsten oxide, zirconium oxide, gallium sulfide, gallium nitride, gallium phosphide, silicon, and high-index polymers can be used to fill the groove 724 . In some embodiments, the recess 724 may be filled with a low-index material such as silicon oxide, aluminum oxide, porous silicon dioxide, or a fluorinated low-index monomer (or polymer). Therefore, the difference between the refractive index of the ridge and the refractive index of the groove may be greater than 0.1, 0.2, 0.3, 0.5, 1.0 or more.

The tilted grating 720 as a diffractive optical element may be wavelength dependent. For example, due to the different wavelengths λ, light of different colors incident at the same angle of incidence may diffract for the same diffraction order at diffraction angles to satisfy the grating equations. Light of the same color from different fields of view can also be diffracted at different angles to satisfy the grating equation.

8 illustrates the propagation of display light 840 and external light 830 in an exemplary waveguide display 800 including waveguide 810 and grating coupler 820 . _The waveguide 810 may be a flat or curved transparent substrate having a refractive index _n2 greater than the free space refractive index n1 (eg, 1.0). The grating coupler 820 may be, for example, a Bragg grating or a surface relief grating.

Display light 840 may be coupled into waveguide 810 by, for example, input coupler 430 of FIG. 4 , or other couplers described above (eg, slanted surfaces or angled surfaces). Display light 840 may propagate within waveguide 810 by, for example, total internal reflection. When the display light 840 reaches the grating coupler 820 , the display light 840 can be diffracted by the grating coupler 820 into, for example, 0-order diffracted (ie, reflected) light 842 and −1-order diffracted light 844 . The 0th order diffraction may propagate within the waveguide 810 and may be reflected at various locations from the bottom surface of the waveguide 810 towards the grating coupler 820 . The −1st order diffracted light 844 may be coupled (eg, refracted) out of the waveguide 810 towards the user's eye because the total internal reflection condition may not be satisfied at the bottom surface of the waveguide 810 due to the angle of diffraction.

The external light 830 can also be diffracted by the grating coupler 820 into, for example, the 0th order diffracted light 832 and the −1st order diffracted light 834 . Both the 0th order diffracted light 832 and the -1st order diffracted light 834 can be refracted out of the waveguide 810 toward the user's eyes. Thus, the grating coupler 820 can act as an input coupler for coupling the external light 830 into the waveguide 810 and can also act as an output coupler for coupling the display light 840 out of the waveguide 810 . Accordingly, the grating coupler 820 may act as a combiner for combining the external light 830 and the display light 840 . In general, the diffraction efficiency (i.e., transmission diffraction) of grating coupler 820 (e.g., surface relief grating coupler) for external light 830 is the same as the diffraction efficiency of grating coupler 820 for display light 840 (ie, reflection diffraction) can be similar or equivalent.

To diffract light in a desired direction toward the user's eye and to achieve a desired diffraction efficiency for certain diffraction orders, the grating coupler 820 may comprise a blazed or sloped grating, such as a sloped Bragg grating or a surface relief grating in which the grating ridges and grooves The grooves may be inclined relative to the surface normal of the grating coupler 820 or waveguide 810 . layered waveguide

Layered waveguides (also referred to herein as "multilayer waveguides") may include multiple waveguide layers of different refractive indices and/or thicknesses bonded together. In one example, a thick optical substrate is bonded to a base layer to form a two-layer waveguide stack. Having multiple waveguide layers may allow selective coupling of certain wavelengths of light and/or angles of light through different layers of the layered waveguide. For example, a waveguide layer of lower index material can be bonded to the base waveguide layer to couple blue light through the waveguide layer of lower index material to increase the brightness of the layered waveguide, such as depicted in the example shown in Figure 9B .

Having multiple bonded waveguide layers can also increase efficiency over a single layer waveguide. For example, as illustrated by comparing the single layer waveguide 910 with the layered waveguide 911 shown in FIGS. 9A and 9B , an already denser field of view (field- of-view; FOV), layered waveguides can improve brightness compared to single-layer waveguides.

Uniformity in a layered waveguide such as the layered waveguide 911 depicted in FIG . Relief towards heterosexual media. For example, a layered waveguide having a thickness of 850 µm thick with a first layer of 500 µm thick SiC, a second layer of 350 µm thick glass and 5 µm thick LC layer (n _e = 1.65 and n ₀ = 1.5).

FIG. 9A illustrates the propagation of external light 930 in an example of a waveguide display 900 with a single layer waveguide 910 and a grating coupler 920 . Single layer waveguide 910 may be flat or curved. The single layer waveguide 910 includes a transparent waveguide layer 940 having a refractive index n ₂ (eg, 2.7) greater than a free space refractive index n ₁ (eg, 1.0). The grating coupler 920 may be, for example, a Bragg grating or a surface relief grating. For simplicity, the illustrated example shows a single bounce of light at the interface between the transparent waveguide layer 940 and the surrounding free space 915 . It will be appreciated that light may bounce multiple times at the interface with free space and/or be transmitted to free space 915 .

Although not shown, in another implementation, display light may also pass through, for example , one or more input couplers, such as input coupler 430 of FIG . or inclined surface)) coupled into the single-layer waveguide 910 . Display light may propagate within the single layer waveguide 910 by, for example, total internal reflection. When the display light reaches the grating coupler 920 , the display light can be diffracted by the grating coupler 920 into, for example, 0-order diffracted (ie, reflected) light and −1-order diffracted light. The 0th order diffraction can propagate in the single-layer waveguide 910 and can be reflected from the bottom surface of the single-layer waveguide 910 toward the grating coupler 920 at different locations. -1st order diffracted light may be coupled (eg, refracted) out of the waveguide 910 towards the user's eye since the total internal reflection condition may not be satisfied at the bottom surface of the single layer waveguide 910 due to the angle of diffraction.

The external light 930 can also be diffracted by the grating coupler 920 into, for example, 0-order diffracted light and −1-order diffracted light. Both the 0th order diffracted light and the -1st order diffracted light can be refracted out of the single layer waveguide 910 toward the user's eyes. Thus, the grating coupler 920 may act as an input coupler for coupling external light 930 into the waveguide 910 and may also act as an output coupler for coupling display light out of the waveguide 910 . Therefore, the grating coupler 920 can act as a combiner for combining the external light 930 and the display light. In general, the diffraction efficiency (i.e., transmission diffraction) of a grating coupler 920 (eg, a surface relief grating coupler) for external light 930 is different from that of a grating coupler 920 for display light ( That is, reflection-diffraction) may be similar or equivalent.

To diffract light in a desired direction toward the user's eye and to achieve a desired diffraction efficiency for certain diffraction orders, the grating coupler 920 may comprise a blazed or sloped grating, such as a sloped Bragg grating or a surface relief grating, in which the grating ridges and grooves The slots may be inclined relative to the surface normal of the grating coupler 920 or waveguide 910 .

FIG. 9B illustrates the propagation of external light 930 in an exemplary waveguide display 901 including a layered waveguide 911 and a grating coupler 920 . The layered waveguide 911 can be flat or curved. The layered waveguide 911 comprises a first transparent waveguide layer 950 having a refractive index n ₂ (eg, 2.7) greater than a free space refractive index n ₁ (eg, 1.0) and a second transparent waveguide layer 960 having a refractive index n ₃ . In this example, the second transparent waveguide layer 960 has a refractive index n ₃ smaller than the refractive index n ₂ , such as, for example, 1.7 to selectively couple eg blue light through the second transparent waveguide layer 960 . The grating coupler 920 may be, for example, a Bragg grating or a surface relief grating. For simplicity, the illustrated example shows a single bounce of light at the interface between the first waveguide layer 950 and the second waveguide layer 960 and between the second waveguide layer 960 and the surrounding free space 915 . It will be appreciated that light may bounce multiple times at the interface.

Although not shown, in another implementation, display light may also pass through, for example, one or more input couplers, such as input coupler 430 of FIG . Or inclined surface)) coupled into the layered waveguide 911 . Display light may propagate within the layered waveguide 911 by, for example, total internal reflection. When the display light reaches the grating coupler 920 , the display light can be diffracted by the grating coupler 920 into, for example, 0-order diffracted (ie, reflected) light and −1-order diffracted light. The 0th order diffraction can propagate in the layered waveguide 911 and can be reflected from the bottom surface of the layered waveguide 911 toward the grating coupler 920 at different locations. The −1st order diffracted light may be coupled (eg, refracted) out of the layered waveguide 911 towards the user's eye because the total internal reflection condition may not be satisfied at the bottom surface of the layered waveguide 911 due to the diffraction angle.

The external light 930 can also be diffracted by the grating coupler 920 into, for example, 0-order diffracted light and −1-order diffracted light. Both the 0th order diffracted light and the −1st order diffracted light can be refracted out of the layered waveguide 911 toward the user's eyes. Thus, the grating coupler 920 may act as an input coupler for coupling external light 930 into the layered waveguide 911 and may also act as an output coupler for coupling display light out of the layered waveguide 911 . Therefore, the grating coupler 920 can act as a combiner for combining the external light 930 and the display light. In general, the diffraction efficiency (i.e., transmission diffraction) of a grating coupler 920 (eg, a surface relief grating coupler) for external light 930 is different from that of a grating coupler 920 for display light ( That is, reflection-diffraction) may be similar or equivalent.

To diffract light in a desired direction toward the user's eye and to achieve a desired diffraction efficiency for certain diffraction orders, the grating coupler 920 may comprise a blazed or sloped grating, such as a sloped Bragg grating or a surface relief grating, in which the grating ridges and grooves The slots may be inclined relative to the surface normal of the grating coupler 920 or the layered waveguide 911 .

FIG. 10A illustrates an example of a waveguide display 1000 with a single layer waveguide 1001 . Waveguide display 1000 includes a substrate 1010 of transparent material, which may be similar to substrate 420 , substrate 610 , or waveguide 710 . Substrate 1010 may include, for example, glass, silicon, silicon nitride, silicon carbide, _LiNbO3 , _TiO2 , GaN, AlN, SiC, CVD masonry, ZnS, or any other suitable material. An input grating 1020 and one or more output gratings 1030 and 1040 may be etched in the substrate 1010 or a layer of grating material formed on the substrate 1010 . The input grating 1020 and output gratings 1030 and 1040 may comprise inclined or vertical surface relief gratings, and may comprise an overcoat filling the grating grooves as described above. Output gratings 1030 and 1040 may be etched on opposing surfaces of substrate 1010 . In some embodiments, only one output grating 1030 or 1040 may be used. As described above with reference to, for example, FIGS. 4 and 6A , input grating 1020 can couple display light of different colors (e.g., red, green, and/or blue) from different viewing angles (or within different FOVs) into substrate 1010, which The incoupled display light can be guided by total internal reflection. Whenever incoupled display light reaches output grating 1030 or 1040 , a portion of the incoupled display light propagating within substrate 1010 may be coupled out of substrate 1010 by output grating 1030 or 1040 toward the human eye window of waveguide display 1000 .

As described above, in order to satisfy the grating equation, light of different colors (wavelengths) and/or from different viewing angles may have different diffraction angles. For example, in the example illustrated in FIG. 10A , two beams of different colors (e.g., red and blue) and the same angle of incidence (e.g., about 0°) can be diffracted by the input grating 1020 into the substrate 1010 different directions. More specifically, light beams with shorter wavelengths (eg, blue light) may have smaller diffraction angles. Two light beams with the same color but different incident angles can also be diffracted by the input grating 1020 to two different directions within the substrate 1010 . Due to the different propagation directions, the two incoupled light beams can reach the surface of the substrate 1010 after propagating different distances in the x-direction. Therefore, light beams with smaller angles relative to the surface normal direction of the substrate 1010 may reach the output grating 1030 or 1040 more times than light beams with larger angles relative to the surface normal direction of the substrate 1010 . Therefore, display lights of different colors or from different FOVs may be directed to the human eye window at different densities, and thus display lights of different colors or from different FOVs may be directed to the user's eyes non-uniformly.

According to some embodiments, to improve the uniformity of the display across all colors and light from all FOVs, layered waveguides can be implemented. Layered waveguides may include waveguide layers having different desired refractive indices and/or thicknesses. In one implementation, multiple waveguide layers in a layered waveguide stack may have the waveguide layer with the highest index of refraction at the center of the layer stack, and the index of refraction of the waveguide layers in the stack may be from the center outward toward both sides of the layer stack. Relative Outer Decrease In some embodiments, the refractive index of the waveguide layer may decrease from one side of the layer stack to the opposite side.

Figure 10B illustrates an example of a layered waveguide display 1002 with a layered waveguide 1003 according to certain embodiments. Multilayer waveguide display 1002 includes a substrate of transparent material (also referred to as a "first waveguide layer") 1012 , input gratings 1022 and 1024 , and output gratings 1032 and 1042 , which may be similar to substrate 1010 , input grating 1020 , and output grating 1030, respectively. and 1040 . The input gratings 1022 and 1024 and the output gratings 1032 and 1042 may be formed in the first waveguide layer 1012 or may be a layer of grating material formed on the first waveguide layer 1012 . In one example, the input gratings 1022 and 1024 and/or the output gratings 1032 and 1042 can be vertical or inclined surface relief gratings formed in the first waveguide layer 1012 or a layer of grating material formed on the first waveguide layer 1012 , and and/or may include a coating that fills the outside of the grating grooves. The multilayer waveguide display 1002 also includes a second waveguide layer 1050 , which may be, for example, a thin layer (e.g., a few hundred microns, such as between about 100 μm and between about 600 µm). In some implementations, the difference between the index of refraction of the first waveguide layer 1012 and the index of refraction of the second waveguide layer 1050 can be about 0.1, 0.2, 0.25, 0.3, or greater.

In the example shown in FIG. 10B , a first light beam 1060 (e.g., having a longer wavelength or larger viewing angle) can be coupled into the first waveguide layer 1012 by the input grating 1022 and can be coupled with respect to the first waveguide layer 1012. The larger angle of the surface normal direction propagates in the first waveguide layer 1012 . Therefore, due to the larger incident angle and larger difference between the refractive indices of the first waveguide layer 1012 and the second waveguide layer 1050 , the first light beam 1060 can pass through the first waveguide layer 1012 and the second waveguide layer through total internal reflection. Interface reflection between 1050 . A second light beam 1062 (e.g., having a shorter wavelength and/or a smaller viewing angle) can be coupled into the first waveguide layer 1012 by the input grating 1022 , and can be at a larger angle relative to the surface normal direction of the first waveguide layer 1012. propagates within the first waveguide layer 1012 . Therefore, due to the smaller angle of incidence, the second light beam 1062 may not be reflected at the interface between the first waveguide layer 1012 and the second waveguide layer 1050 by total internal reflection. Thus, the second light beam 1062 can instead be refracted at the interface into the second waveguide layer 1050 at a larger refraction angle, and can then be attributed to the increased angle of incidence and the difference between the refractive index of the second waveguide layer 1050 and air. Larger differences (eg, about 0.5) are reflected at the bottom surface of the second waveguide layer 1050 by total internal reflection. Thus, even though the second beam 1062 may have a smaller propagation angle than the first beam 1060 relative to the surface normal direction of the first waveguide layer 1012 , the second beam 1062 may travel in the z direction before being reflected by total internal reflection A longer distance, and thus can travel a similar distance in the x-direction as the first beam 1060 before being reflected by total internal reflection. In this way, the first beam 1060 and the second beam 1062 may be diffracted by the output grating 1032 or 1042 about the same number of times at about the same interval to improve uniformity. The thickness and refractive index of the first waveguide layer 1012 and the second waveguide layer 1050 can be selected to achieve the desired performance.

FIG. 11A illustrates an example of a multilayer waveguide display 1100 including a layered waveguide 1101 according to certain embodiments. Multilayer waveguide display 1100 may include a first waveguide layer having one or more input gratings and/or one or more output gratings. In FIG. 11A , a multilayer waveguide display 1100 includes a first waveguide layer 1110 having input gratings 1120 and 1122 and output gratings 1130 and 1140 formed in a first waveguide layer 1012 or similar to the waveguide display 1000 and described above. The multilayer waveguide display 1002 is formed on a layer of grating material on the first waveguide layer 1012 . The first waveguide layer 1110 may include, for example, glass, silicon, silicon nitride, silicon carbide, _LiNbO3 , _TiO2 , GaN, AlN, SiC, CVD diamond, ZnS, and the like. The input gratings 1120 and 1122 and/or the output gratings 1130 and 1140 may be inclined or vertical surface relief gratings and may include coatings that fill the grooves of the gratings. The multilayer waveguide display 1100 also includes a second waveguide layer 1150 and a third waveguide layer 1160 on opposite sides of the first waveguide layer 1110 . The second waveguide layer 1150 and the third waveguide layer 1160 may each be a thin layer (e.g., a few hundred micrometers, such as between about 100 μm and about 600 μm) of a transparent material having a lower refractive index than the first waveguide layer 1110 . between). For example, the difference between the refractive index of the first waveguide layer 1110 and the refractive index of the second waveguide layer 1150 or the third waveguide layer 1160 can be about 0.1, 0.2, 0.25, 0.3 or more. The multilayer waveguide display 1100 can achieve a more uniform reproduction of light with different colors and/or from different FOVs as described above with respect to Figure 10B . The thickness and refractive index of the first waveguide layer 1110 , the second waveguide layer 1150 , and the third waveguide layer 1160 can be selected to achieve the desired performance.

FIG. 11B illustrates an example of a multilayer waveguide display 1102 including a layered waveguide 1103 according to certain embodiments. The multilayer waveguide display 1102 may include a first waveguide layer having one or more input gratings and one or more output gratings. In FIG. 11B , multilayer waveguide display 1102 includes a first waveguide layer 1112 having input gratings 1124 and 1126 and output gratings 1132 and 1142 formed thereon in waveguide display 1000 and multilayer waveguide display 1002 or 1100 as described above. . The first waveguide layer 1112 may include, for example, glass, silicon, silicon nitride, silicon carbide, _LiNbO3 , _TiO2 , GaN, AlN, SiC, CVD diamond, ZnS, and the like. The input gratings 1124 and 1126 and the output gratings 1132 and 1142 may be inclined or vertical surface relief gratings and may include overcoatings that fill the grating grooves as described above with respect to eg FIG. 7 . The multilayer waveguide display 1102 also includes a second waveguide layer 1152 and a third waveguide layer 1162 on opposite sides of the first waveguide layer 1112 . The second waveguide layer 1152 and the third waveguide layer 1162 may each be a thin layer (e.g., a few hundred microns, such as between about 100 μm and about 600 µm). In one example, the difference between the refractive index of the first waveguide layer 1112 and the refractive index of the second waveguide layer 1152 or the third waveguide layer 1162 may be about 0.1, 0.2, 0.25, 0.3 or greater. The second waveguide layer 1152 and the third waveguide layer 1162 may have the same or different refractive indices and/or may have the same or different thicknesses.

Additionally, a fourth waveguide layer may be formed on the second waveguide layer 1152 and a fifth waveguide layer may be formed on the third waveguide layer 1162 . In FIG. 11B , multilayer waveguide display 1102 includes fourth waveguide layer 1170 disposed adjacent to second waveguide layer 1152 and fifth waveguide layer 1180 disposed adjacent to third waveguide layer 1162 . Fourth waveguide layer 1170 and fifth waveguide layer 1180 may each be a thin layer ( e.g., a few hundred microns, such as between about 100 µm and about 600 µm). In one example, the difference between the index of refraction of the second waveguide layer 1152 and the index of refraction of the fourth waveguide layer 1170 and the difference between the index of refraction of the third waveguide layer 1162 and the index of refraction of the fifth waveguide layer 1180 may be About 0.1, 0.2, 0.25, 0.3 or more. The fourth waveguide layer 1170 and the fifth waveguide layer 1180 may have the same or different refractive indices and/or may have the same or different thicknesses. The multilayer waveguide display 1102 can achieve a more uniform reproduction of light with different colors and/or from different FOVs as described above with respect to Figure 8B . The thickness and/or refractive index of the first waveguide layer 1112 , the second waveguide layer 1152 , the third waveguide layer 1162 , the fourth waveguide layer 1170 , and the fifth waveguide layer 1180 can be selected to achieve the desired performance.

While the illustrated examples of waveguide stacks 1100 and 1102 in FIGS. 11A and 11B show a layered waveguide 1101 with three waveguide layers 1110 , 1150 , 1160 , and a layer with five waveguide layers 1112 , 1152 , 1162 , 1170 , 1180 shaped waveguide 1102 , but may include fewer or additional waveguide layers in other implementations. For example, in one implementation, the multilayer waveguide display 1100 in FIG. 11A may not include the second waveguide layer 1150 or the third waveguide layer 1160 . As another example, in one implementation, multilayer waveguide display 1102 may not include waveguide layers 1162 and 1180 or waveguide layers 1152 and 1170 .

In various embodiments, the multilayer waveguide displays disclosed herein can include layered waveguides having two or more waveguide layers, such as three, four, five or more layers. In some embodiments, the waveguide layer with the lowest index of refraction (also known as the low-index waveguide layer) can be positioned on the same side as the input and output gratings, and the waveguide layer with the highest index of refraction (also known as the high-index waveguide layers) may be positioned on opposite sides of the layer stack. For example, waveguide layers may be configured in a waveguide stack to lower the index of refraction from one side of the layer stack to the opposite side, for example where the waveguide layer with the lowest index of refraction is positioned on the side with the input and output gratings. In another example, the waveguide layer with the lowest index of refraction can be positioned on the opposite side of the layer stack. For example, waveguide layers may be configured in a waveguide stack where the waveguide layer has the highest index of refraction at the center of the stack, and then other waveguide layers are configured to decrease (eg, gradually decrease) the index of refraction towards opposite sides of the layer stack. In some cases, the refractive index profile of the waveguide layer stack may be symmetric and have the highest value, such as at the center of the layer stack. For example, referring to the stack shown in FIG. 11B , the first waveguide layer 1112 may have the highest index of refraction in the stack at the center of the stack, the third waveguide layer 1162 may have a lower index of refraction than the first waveguide layer 1112 , The fifth waveguide layer 1180 can have a lower refractive index than the third waveguide layer 1162 , the second waveguide layer 1152 can have a lower refractive index than the first waveguide layer 1112 and/or the fourth waveguide layer 1170 can have a lower refractive index than the second waveguide layer 1170. The refractive index of layer 1152 . In other cases, the refractive index profile of the waveguide layer stack may not be symmetrical about the center of the waveguide layer stack.

Multiple waveguide layers with different refractive indices and thicknesses (e.g., 100 or 200 µm) may need to be flat with low total thickness variation (e.g., <1 µm) or surface roughness (e.g., with a mean square root area roughness). Multiple waveguide layers may need to have low transmitted haze and will not require polishing. It may also be desirable to fabricate multiple waveguide layers at low temperatures, such as room temperature. Therefore, it can be challenging to fabricate multiple waveguide layers on a substrate on which grating couplers are etched. Multilayer waveguides can be formed by bonding multiple low index substrates or layers to a substrate (eg, SiC substrate), by lamination, by slot coating, chemical vapor deposition (eg, PECVD), or the like. production. However, these techniques may not be able to achieve the desired properties of multiple waveguide layers. Inkjet 3-D printing

According to some embodiments, multilayer (lamellar) waveguides can be fabricated using one or more inkjet 3-D printing techniques. During inkjet 3-D printing, a number of small droplets of resin material (sometimes referred to herein as ink) can be deposited on a substrate with input and output gratings formed thereon. The number of small droplets of resin material (eg, in the form of a two-dimensional array) can form a uniform thin layer (eg, about 10 µm), which can be crosslinked, eg, by ultraviolet (UV) curing or heat treatment. One or more additional thin layers of resin material may be deposited on the first cross-linked thin layer and cross-linked until the desired total thickness of the waveguide layer is achieved. For example another waveguide layer with a different (e.g. lower) refractive index can be printed on the already printed waveguide layer (e.g. with a higher refractive index than the other waveguide layer) or can be printed on the waveguide opposite the already printed waveguide layer on one side of the layer stack.

Using the 3-D printing techniques disclosed herein, material can be deposited only on selected areas of interest, such as only on top of a functional device (eg, an output grating). Only one dicing operation may be required to form individual devices from a base wafer on which one or more waveguide layers are deposited. Both the base wafer and other substrates need not be diced and then bonded together. Materials used in 3-D printing techniques may have lower densities than, for example, SiC substrates (eg, about 3.21 g/cm ³ ), fused silica (eg, about 2.17 g/cm ³ ), or other substrate materials (eg, , about 1.25 g/cm ³ ). Therefore, waveguide displays fabricated using 3-D printing can have a lighter weight than waveguide displays fabricated by other deposition techniques. Additionally, materials for 3-D printing can be tuned to have a desired index of refraction. For example, high refractive index nanoparticles can be added to the resin material to tune the refractive index of the resin material. In one implementation, for example, high refractive index nanoparticles may be added to the resin material to increase the refractive index of the resin material from about 1.45 or lower to about 2.0 or higher. In another implementation, high refractive index nanoparticles may be added to the resin material to increase the refractive index of the resin material from about 1.45 or lower to between about 1.5 and about 1.8.

In some embodiments, materials for inkjet 3-D printing technology may include a base resin having at least one actinic light curable moiety selected from the group comprising: acrylate, epoxy, vinyl, sulfur Alcohols, allyls, vinyl ethers, allyl ethers, epoxy acrylates, urethane acrylates, and acrylic polyesters. Materials for inkjet 3-D printing may also include photoinitiators, such as photo radical generators (PRG) or photoacid generators. The nanoparticles used to tune the refractive index of the resin material may include metal oxides, such as titanium oxide, zirconium oxide, hafnium oxide, tungsten oxide, zinc telluride, gallium phosphide, derivatives of any of the foregoing materials, or the like. Any combination of materials. Method for manufacturing layered (multilayer) waveguides

In general, multilayer waveguides are fabricated by bonding multiple waveguide layers together. For example, an optically clear adhesive (OCA) or other bonding material may be used to bond one or more waveguide layers to a base waveguide layer having one or more waveguide die disposed thereon to form a bonded waveguide stack. One or more individual waveguides may be severed from the bonded waveguide stack in a dicing process.

A method of fabricating multilayer waveguides may use a dicing process that performs laser ablation, or the like, to cut through the bonded waveguide stack to singulate individual waveguides. Laser ablation may employ a high power laser to repeatedly remove material in regions to scratch through multiple layers of the waveguide stack. If bonding material (eg, optically clear adhesive) is present at the edges of waveguide die during the dicing operation, laser ablation or other similarly destructive processes can reduce the bond strength of the bonding material at the edges of individual waveguides. Certain bonding processes may generate residual stress in the bonding material layer due to, for example, polymerization shrinkage during an ultraviolet (UV) curing process or due to a coefficient of thermal expansion (CTE) mismatch during a thermal bonding process. In some instances, delamination may begin at the edge of the waveguide prior to relieving residual stress in the bonding material layer, where the bonding strength of the bonding layer may have been reduced during the dicing process. This delamination front can then propagate inwards over time, creating delamination between the waveguide layers. Figure 21A depicts an example of a waveguide stack 2101 prior to a cutting operation. FIG. 21B depicts a multilayer waveguide 2102 with delamination at its edges after a cutting operation. In the example shown in FIG. 21B, a sawing operation is performed on a bonded waveguide stack having one or more waveguide dies, wherein bonding material is present at the edges of the one or more waveguide dies during the sawing operation.

Some example formations of the methods of making layered waveguides described herein may be free (or substantially free, such as more than A bonded waveguide stack that is 90% free or more than 99% free of bonding material. Some of these examples are described below with reference to Figures 14-19 .

In certain implementations, the layered waveguide is formed in part by selectively dispensing (e.g., by inkjet deposition) an optically clear adhesive (OCA) material or other bonding material, and after bonding the waveguide layers by bonding the bonded The material is formed by exposing the material to ultraviolet (UV) light and/or thermal processes to cure the bonding material. The OCA material or other bonding material can be a blend of relatively low molecular weight monomers that can be exposed to UV light after bonding. OCA materials or other bonding materials may have properties including one or more of the following: (i) may flow as a neat material for good contact during bonding; (ii) may be subsequently mixed with a suitable photoinitiator such as , cationic, anionic, free radical) conjugative cross-linking; (iii) low light loss including turbidity and absorption; (iv) high refractive index (eg, greater than 1.5 or greater than 1.6); (v) good adhesion/wetting properties (containing hydrogen bonding/polar groups); and (VI) good bonding strength in the cross-linked state. In such implementations, the first (base) waveguide layer may have a substrate comprising one or more of: siloxane, silsesquioxane, (thio)urethane, amide, ( Thio)urea, (thio)carbonate, (thio)phosphate, aromatic (terrene, biphenyl, benzodithiophene and similar). In some cases, monomeric functional groups may be added to substrates including one or more of: (i) free radical (meth)acrylate, acrylamide, styrene, vinyl carbonyl, vinyl ring propane and the like; or (ii) ring-opening materials such as cyclic ethers (eg, epoxides, propylene oxide, and the like) cyclic carbonyls (eg, carbonates, lactones, and the like). In one example, the substrate is 67% fluorene diacrylate, 30% glycidyl POSS, 3% PAG (365 nm). In another example, the substrate is a solvent (PGMEA) containing 20-60 wt% solids.

In certain implementations, the optically clear adhesive material or other bonding material can have a lower index of refraction than that of one or more layers of the waveguide stack. For example, the optically clear adhesive material or other bonding material may have a lower index of refraction than that of the waveguide layer having the lowest index of refraction (also sometimes referred to as the lowest index layer) in the waveguide stack. In one example, the lowest index layer has a refractive index of 1.7 and the OCA material or other bonding material has a refractive index of 1.6. In another example, the lowest index layer has a refractive index of 1.7 and the OCA material or other bonding material has a refractive index of 1.5.

In certain implementations, the layer is formed in part by thermally bonding an optically clear adhesive material or other bonding material and selectively patterning the layer of bonding material to remove material, such as removing material at one or more dicing channels shaped waveguide. In some cases, an optically clear adhesive material or other bonding material can include a high molecular weight thermoplastic polymer that can be melted for thermal bonding and then cooled to increase bond strength. Optically clear adhesive materials or other bonding materials may have properties including one or more of the following: (i) low Tg (eg, <150 C or preferably less than 100 C) for thermal bonding; (ii) may Photopatternable in positive or negative tone development processes; (iii) can be crosslinked after bonding with appropriate chemistry (e.g., cationic, anionic, radical, thermal); (iv) low light including haze and absorption Loss; (v) high refractive index (eg, greater than 1.5 or greater than 1.6); and (vi) good bond strength in the crosslinked state (eg, tunable MW, crosslinkable). In such implementations, the first waveguide layer (sometimes referred to as the base waveguide layer) may have a substrate comprising one or more of: siloxane, silsesquioxane, (thio)urethane Esters, amides, (thio)ureas, (thio)carbonates, (thio)phosphates, aromatics (tribene, biphenyl, benzodithiophene and similar). Monomer functional groups may be added to substrates comprising one or more of: (i) free radical (meth)acrylate, acrylamide, styrene, vinylcarbonyl, vinylcyclopropane; or (ii) ) ring-opening materials, such as cyclic ethers (epoxides, propylene oxide, etc.), cyclic carbonyls (carbonates, lactones, etc.). In one example, the substrate is a 30 kDa copolymer containing 30% tert-butyl methacrylate, 50% biphenyl methacrylate, and 20% glycidyl methacrylate. In another example, the substrate was PGMEA solvent at 20% solids (97% polymer: 3% PAG).

12 is a diagram 1200 illustrating an example of a process flow depicting operations of a method of fabricating a layered waveguide, according to certain embodiments. The operations depicted in diagram 1200 are for purposes of illustration only and are not intended to be limiting. In various implementations, diagram 1200 may be modified to add additional operations, omit some operations, or change the order of operations. One or more of the operations described in diagram 1200 may be performed using, for example, one or more semiconductor manufacturing systems, such as ink jet systems, spin coating systems, chemical vapor deposition (CVD) systems, physical vapor deposition (physical vapor deposition; PVD) systems, ion or plasma etching (for example, ion beam etching (IBE), plasma etching (PE) or reactive ion etching (RIE)) systems and the like.

12 depicts a first (base) waveguide layer 1210 (e.g., glass, silicon, silicon nitride, silicon carbide, LiNbO ₃ , TiO ₂ , GaN , AlN, SiC, CVD diamond, ZnS wafer, etc.). At operation 1260 , a layer 1220 of optically clear adhesive (OCA) material or other bonding material is deposited on the first waveguide layer 1210 .

At operation 1270 , second waveguide layer 1230 , such as a low index substrate or other layer, is bonded to first waveguide layer 1210 , optically clear adhesive (OCA) material layer or other bonding material layer 1220 in a bonding process to form a waveguide Stack 1235 . The bonding process may include ultraviolet (UV) curing and/or thermal bonding processes.

At operation 1280 , a dicing process is performed to form one or more individual waveguide devices 1240 (eg, one, two, three, four, five or more waveguide devices) from the waveguide stack 1235 . In the illustrated example, four waveguide devices 1240 are formed from waveguide stack 1235 . The dicing process may include laser ablation or other similar techniques for cutting through the waveguide stack 1235 . In some cases, the first waveguide layer 1210 may have a higher index of refraction than the second waveguide layer 1230 to produce index modulation.

Although not shown, the method of fabricating the multilayer waveguide shown in FIG. 12 may also include one or more operations for forming one or more input and/or output gratings in the first waveguide layer 1210 (e.g., by etching). The input and output gratings may comprise, for example, inclined or vertical surface relief gratings.

FIG. 13 includes a flowchart 1300 depicting an example of operations in a method of fabricating a multilayer waveguide according to certain embodiments. Certain operations may be similar to those depicted in FIG. 12 . The operations shown in flowchart 1300 are for purposes of illustration only and are not intended to be limiting. In various implementations, flowchart 1300 may be modified to add additional operations, omit some operations, or change the order of operations. The operations described in flowchart 1300 may be performed using, for example, one or more semiconductor manufacturing systems, such as ink jet systems, spin coating systems, chemical vapor deposition (CVD) systems, physical vapor deposition (PVD) systems, ion or Plasma etching (eg, ion beam etching (IBE), plasma etching (PE), or reactive ion etching (RIE)) systems and the like.

At operation 1310 , a first waveguide layer (e.g., glass, silicon, silicon nitride, silicon carbide, _LiNbO3 , _TiO2 , GaN, AlN, SiC, CVD diamond, ZnS wafer, etc.). The first waveguide layer may have one or more input and/or output gratings formed thereon.

At operation 1320 , a layer of optically clear adhesive (OCA) material or other bonding layer is deposited on the first waveguide layer.

At operation 1330 , the second waveguide layer is bonded to the first waveguide layer in a bonding process using a bonding layer, such as an OCA material. The bonding process may include UV curing and/or thermal bonding processes.

At an optional (depicted by dashed lines) operation 1335 , one or more additional waveguide layers are bonded to the second waveguide layer to supplement the waveguide stack. For example, each additional waveguide layer may be formed on the waveguide stack by depositing an additional bonding layer and bonding the respective additional waveguide layer in a bonding step. In certain aspects, the first waveguide layer can have a higher index of refraction than the second waveguide layer and/or other additional waveguide layers in the stack to produce index modulation at interfaces. For example, the refractive index of multiple waveguide layers may be reduced from a first waveguide layer by subsequent bonded waveguide layers. In some instances, the materials and thicknesses of the waveguide layers in the stack can selectively couple wavelengths of light passing through the layers in the waveguide.

At operation 1340 , a dicing process is performed to cut through the bonded waveguide stack to form one or more individual waveguide devices. device. The dicing process may include laser ablation or other similar techniques for cutting through the waveguide stack. Method for Fabricating Layered Waveguides Using Selective Deposition / Removal

In certain implementations, the method of fabricating a layered waveguide removes or avoids the formation of adhesive or other bonding material in one or more dicing channels in a bonded waveguide stack to be diced. In this way, the properties of the bonding material layer may not be affected by the dicing process, and delamination due to reduced bonding strength by laser ablation or other similar operations occurring during the dicing process may be avoided. Such methods of fabricating layered waveguides may result in one or more cut lines that may be free (or substantially free, such as more than 90% free or more than 99% free) of bonding material around respective waveguide dies bonded waveguide stack.

14 includes a diagram 1400 illustrating an example of a process flow depicting operations of a method of fabricating a layered waveguide according to an embodiment. The operations depicted in diagram 1400 are for purposes of illustration only and are not intended to be limiting. In various implementations, diagram 1400 may be modified to add additional operations, omit some operations, or change the order of operations. One or more operations described in diagram 1400 may be performed using, for example, one or more semiconductor manufacturing systems, such as inkjet systems, spin coating systems, chemical vapor deposition (CVD) systems, physical vapor deposition (PVD) systems , ion or plasma etching (eg, ion beam etching (IBE), plasma etching (PE), or reactive ion etching (RIE)) systems, and the like.

14 depicts a first waveguide layer 1410 (e.g., glass, silicon, silicon nitride, silicon carbide, LiNbO ₃ , TiO ₂ , GaN, AlN, SiC, CVD diamond, ZnS wafer ) with one or more waveguide dies 1412 wait). At operation 1460 , a layer 1420 of an optically clear adhesive material such as a transparent bonding material or other bonding material is deposited on the first waveguide layer 1410 and one or more dicing channels 1422 are formed in the bonding layer 1420 . In certain implementations, the one or more cut channels 1422 may be deposited using techniques described herein as part of an additive process of depositing bonding material in the region of the first waveguide layer 1410 outside the one or more cut channels 1422 . For example, an inkjet process or a drop casting process may be used to selectively deposit bonding material (eg, OCA material) on regions of the first waveguide layer 1410 outside of the one or more dicing channels 1422 . In this example, one or more cutting channels 1422 can remain free or substantially free of bonding material. In other implementations, an ablation process may be used to remove material at one or more dicing channels 1422 to expose the first waveguide layer 1410 . For example, bonding layer 1420 may be deposited, such as by spin coating, and an etching process, such as a lithography process, may be used to remove material from one or more dicing channels 1422 . Before the etching process, the mask layer can be patterned on the first waveguide layer 1410 using a dicing channel pattern. The mask layer may comprise, for example, a metal or metal alloy material such as chromium or chromium oxide. The mask layer may have high resistance for dry etching, such as plasma etching. An etch process may then be performed to remove bonding material from bonding layer 1420 in one or more dicing channels 1422 . In one aspect, a photolithographic patterning process including positive tone development or negative tone development may be performed.

At operation 1470 , the second waveguide layer 1430 is bonded to the first waveguide layer 1410 using the bonding layer 1420 in a bonding process to form a bonded waveguide stack 1435 . The bonding process may include UV curing and/or thermal bonding processes. In one implementation, the second waveguide layer 1430 may have a lower index of refraction than the first waveguide layer 1410 , for example, to produce index modulation.

At operation 1480 , a dicing process is performed to form one or more individual layered waveguides 1440 (also referred to as layered waveguide devices) from the bonded waveguide stack 1435 . The dicing process may include laser ablation or other similar techniques for cutting through bonded waveguide stack 1435 in one or more dicing channels 1422 . Although not shown, in another implementation, the fabrication depicted in FIG. 14 may also include forming in or on the exterior surfaces of the first waveguide layer 1410 and/or the second waveguide layer 1430 (e.g., by etch) one or more input gratings and/or output gratings. The input grating and/or the output grating may comprise, for example, inclined or vertical surface relief gratings.

In FIG. 14 , a layer of bonding material 1420 is disposed over the entire first waveguide layer 1410 except in one or more cut channels 1422 . In other implementations, the bonding material layer 1420 may be disposed in a region above the one or more waveguide dies 1412 and not be disposed in at least a portion of the region outside of the one or more dicing channels 1422 . In another implementation, the waveguide die 1412 may be within one or more dicing channels 1422 .

FIG. 15 includes a flowchart 1500 depicting the operations of an example of a method of fabricating a layered waveguide according to embodiments. Some of the operations may be similar to those depicted in FIG. 14 . The operations depicted in diagram 1500 are for purposes of illustration only and are not intended to be limiting. In various implementations, diagram 1500 may be modified to add additional operations, omit some operations, or change the order of operations. For example, although not shown, the process may also include forming one or more input and/or output gratings in or on the outer surface of the first waveguide layer and/or the second waveguide layer. The input grating and/or the output grating may comprise, for example, inclined or vertical surface relief gratings. One or more of the operations described in diagram 1500 may be performed using, for example, one or more semiconductor manufacturing systems, such as ink jet systems, spin coating systems, chemical vapor deposition (CVD) systems, physical vapor deposition (PVD) systems , ion or plasma etching (eg, ion beam etching (IBE), plasma etching (PE), or reactive ion etching (RIE)) systems, and the like.

At operation 1510 , a first waveguide layer (e.g., glass, silicon, silicon nitride, silicon carbide, _LiNbO3 , TiO ₂ , GaN, AlN, SiC, CVD diamond, ZnS wafer, etc.). In one implementation, the first waveguide layer may have one or more input and/or output gratings formed in or on the surface of the first waveguide layer.

At operation 1520 , an optically clear adhesive (OCA) material or other bonding material is deposited on the first waveguide layer, and one or more cut channels are formed in the bonding material layer. In certain implementations, one or more dicing channels may be deposited using techniques described herein as part of an additive process of depositing bonding material in regions of the first waveguide layer outside of the dicing channels. For example, an inkjet process or a drop casting process may be used to selectively deposit bonding material (eg, OCA material) on regions of the first waveguide layer outside the one or more cut channels. In this example, one or more cutting channels may remain free or substantially free of bonding material. In other implementations, an ablation process may be used to remove material at one or more dicing channels, thereby exposing the first waveguide layer. For example, a bonding layer can be deposited, such as by spin coating, and an etching process, such as a lithography process, can be used to remove material from one or more dicing channels. Before the etching process, the mask layer can be patterned on the first waveguide layer using a dicing channel pattern. The mask layer may comprise, for example, a metal or metal alloy material such as chromium or chromium oxide. The mask layer may have high resistance for dry etching, such as plasma etching. An etch process may then be performed to remove bonding material from the bonding layer in the one or more dicing channels. In one aspect, a photolithographic patterning process including positive tone development or negative tone development may be performed.

At operation 1530 , the second waveguide layer is bonded onto the first waveguide layer using the bonding material deposited in operation 1520 in a bonding process to form a bonded waveguide stack. The bonding process may include UV curing and/or thermal bonding processes. In one implementation, the second waveguide layer may have a lower refractive index than the first waveguide layer. The respective indices of refraction of the first and second waveguide layers can be selected for the desired index modulation. A bonded waveguide stack may have one or more cut channels free or substantially free of bonding material. In one implementation, the bonding material is disposed over the entire first waveguide layer except in the one or more cut channels. In another implementation, the bonding material may only be disposed within the inner perimeter of one or more cutting channels. In some cases, one or more dicing channels surround one or more waveguide dies and do not overlap or include portions of one or more waveguide dies. In other cases, one or more waveguide dies are in respective one or more dicing channels.

At an optional operation 1535 (depicted by dashed lines), one or more additional waveguide layers are bonded to the second waveguide layer and/or the first waveguide layer to supplement the bonded waveguide stack. For example, each additional waveguide layer can be formed on the waveguide stack by depositing an additional bonding layer and bonding the respective additional waveguide layer in a bonding step. In certain aspects, the first waveguide layer can have a higher index of refraction than the second waveguide layer and/or other additional waveguide layers in the stack to produce index modulation at interfaces. For example, the refractive index of the waveguide layer can be reduced from the first waveguide layer by subsequent bonded waveguide layers. In some instances, the materials and thicknesses of the waveguide layers in the stack can selectively couple wavelengths of light passing through the layers in the waveguide.

At operation 1540 , a dicing process is performed to cut through the bonded waveguide stack at one or more dicing channels to form one or more individual layered waveguides. The dicing process may include laser ablation or other similar techniques for cutting through the waveguide stack. Method for fabricating layered waveguides using selective deposition / removal and cutting of sacrificial materials in vias

In certain implementations, the method of making a layered waveguide forms a sacrificial material in one or more cut channels in a bonding layer between waveguide layers. The sacrificial material can be a material that is not normally bonded to the bonding layer. In one aspect, the sacrificial material is an inert polymeric material. In another aspect, the sacrificial material has orthogonal reactivity with the material of the bonding layer.

16 includes a diagram 1600 illustrating an example of a process flow depicting operations of a method of fabricating a layered waveguide according to an embodiment. The operations depicted in diagram 1600 are for purposes of illustration only and are not intended to be limiting. In various implementations, diagram 1600 may be modified to add additional operations, omit some operations, or change the order of operations. One or more operations described in diagram 1600 may be performed using, for example, one or more semiconductor manufacturing systems, such as inkjet systems, spin coating systems, chemical vapor deposition (CVD) systems, physical vapor deposition (PVD) systems , ion or plasma etching (eg, ion beam etching (IBE), plasma etching (PE), or reactive ion etching (RIE)) systems, and the like.

16 depicts a first waveguide layer 1610 (e.g., glass, silicon, silicon nitride, silicon carbide, LiNbO ₃ , TiO ₂ , GaN, AlN, SiC, CVD diamond, ZnS wafer ) with one or more waveguide die 1612 wait). At operation 1660 , a layer 1620 of an optically clear adhesive material such as a transparent material or other bonding material is deposited on the first waveguide layer 1610 and one or more dicing channels 1622 are formed in the bonding layer 1620 . In certain implementations, the one or more dicing channels 1622 may be deposited using techniques described herein as part of an additive process of depositing bonding material in regions of the first waveguide layer 1610 outside of the one or more dicing channels 1622 . For example, an inkjet process or a drop casting process may be used to selectively deposit bonding material (eg, OCA material) on regions of the first waveguide layer 1610 outside of the one or more dicing channels 1622 . In other implementations, an ablation process may be used to remove material at one or more dicing channels 1622 to expose the first waveguide layer 1610 . For example, bonding layer 1620 may be deposited, such as by spin coating, and an etching process, such as a lithography process, may be used to remove material from one or more dicing channels 1622 . Before the etching process, the mask layer can be patterned on the first waveguide layer 1610 using a dicing channel pattern. The mask layer may comprise, for example, a metal or metal alloy material such as chromium or chromium oxide. The mask layer may have high resistance for dry etching, such as plasma etching. An etch process may then be performed to remove bonding material from bonding layer 1620 in one or more dicing channels 1622 . In one aspect, a photolithographic patterning process including positive tone development or negative tone development may be performed.

At operation 1665 , sacrificial material 1624 is deposited into one or more dicing channels 1622 . For example, an inkjet deposition process or a drop casting process may be used to selectively deposit sacrificial material 1624 into one or more dicing channels 1622 of bonding layer 1620 . The sacrificial material can be a material that is not normally bonded to the bonding layer. In one aspect, the sacrificial material is an inert polymeric material. In another aspect, the sacrificial material has orthogonal reactivity with the material of the bonding layer.

At operation 1670 , the second waveguide layer 1630 is bonded to the first waveguide layer 1610 using the bonding layer 1620 in a bonding process to form a bonded waveguide stack 1635 . The bonding process may include UV curing and/or thermal bonding processes. In one implementation, the second waveguide layer 1630 may have a lower index of refraction than the first waveguide layer 1610 , for example, to produce index modulation.

At operation 1680 , a dicing process is performed to form one or more individual layered waveguides 1640 (also referred to as layered waveguide devices) from the bonded waveguide stack 1635 . The dicing process may include laser ablation or other similar techniques for cutting through bonded waveguide stack 1635 at one or more dicing channels 1622 . Although not shown, in another implementation, the process depicted in FIG. 16 may also include forming (e.g. , by etching ) one or more input gratings and/or output gratings. The input grating and/or the output grating may comprise, for example, inclined or vertical surface relief gratings.

In FIG. 16 , a layer of bonding material 1620 is disposed over the entire first waveguide layer 1610 except in one or more cut channels 1622 . In other implementations, the bonding material layer 1620 may be disposed in a region above the one or more waveguide die 1612 and not disposed in at least a portion of the region outside the one or more dicing channels 1622 . In another implementation, the waveguide die 1612 may be within one or more dicing channels 1622 .

FIG. 17 includes a flowchart 1700 depicting the operations of an example of a method of fabricating a layered waveguide according to embodiments. Some of the operations may be similar to those depicted in Figures 14 and 16 . The operations depicted in diagram 1700 are for purposes of illustration only and are not intended to be limiting. In various implementations, diagram 1700 may be modified to add additional operations, omit some operations, or change the order of operations. For example, although not shown, the process may also include forming one or more input and/or output gratings in or on the outer surface of the first waveguide layer and/or the second waveguide layer. The input grating and/or the output grating may comprise, for example, inclined or vertical surface relief gratings. One or more operations described in diagram 1700 may be performed using, for example, one or more semiconductor manufacturing systems, such as inkjet systems, spin coating systems, chemical vapor deposition (CVD) systems, physical vapor deposition (PVD) systems , ion or plasma etching (eg, ion beam etching (IBE), plasma etching (PE), or reactive ion etching (RIE)) systems, and the like.

At operation 1710 , a first waveguide layer (e.g., glass, silicon, silicon nitride, silicon carbide, _LiNbO3 , TiO _2. GaN, AlN, SiC, CVD diamond, ZnS wafer, etc.). In one implementation, the first waveguide layer may have one or more input and/or output gratings formed in or on the surface of the first waveguide layer.

At operation 1720 , an optically clear adhesive (OCA) material or other bonding material is deposited on the first waveguide layer, and one or more cut channels are formed in the bonding material layer. In certain implementations, one or more dicing channels may be deposited using the techniques described herein as part of an additive process of depositing bonding material in the region of the first waveguide layer outside the dicing channels. For example, an inkjet process or a drop casting process may be used to selectively deposit bonding material (eg, OCA material) on regions of the first waveguide layer outside the one or more cut channels. In other implementations, an ablation process may be used to remove material at one or more dicing channels, thereby exposing the first waveguide layer. For example, a bonding layer can be deposited, such as by spin coating, and an etching process, such as a lithography process, can be used to remove material from one or more dicing channels. Before the etching process, the mask layer can be patterned on the first waveguide layer using a dicing channel pattern. The mask layer may comprise, for example, a metal or metal alloy material such as chromium or chromium oxide. The mask layer may have high resistance for dry etching, such as plasma etching. An etch process may then be performed to remove bonding material from the bonding layer in the one or more dicing channels. In one aspect, a photolithographic patterning process including positive tone development or negative tone development may be performed.

At operation 1725 , sacrificial material is deposited into the one or more cutting channels. For example, an inkjet process or a drop casting process may be used to selectively deposit sacrificial material into one or more dicing channels.

At operation 1730 , the second waveguide layer is bonded to the first waveguide layer using a bonding layer, such as an OCA material, in a bonding process. The bonding process may include UV curing and/or thermal bonding processes.

At operation 1730 , the second waveguide layer is bonded to the first waveguide layer in a bonding process using a bonding material having one or more cut channels of sacrificial material to form a bonded waveguide stack. The bonding process may include UV curing and/or thermal bonding processes. In one implementation, the second waveguide layer may have a lower refractive index than the first waveguide layer. The respective indices of refraction of the first and second waveguide layers can be selected for the desired index modulation. A bonded waveguide stack may have one or more cut channels free or substantially free of bonding material. In one implementation, the bonding material is disposed over the entire first waveguide layer except in the one or more cut channels. In another implementation, the bonding material may only be disposed within the inner perimeter of one or more cutting channels. In some cases, one or more dicing channels surround one or more waveguide dies and do not overlap or include portions of one or more waveguide dies. In other cases, one or more waveguide dies are in respective one or more dicing channels.

At an optional operation 1735 (depicted by dashed lines), one or more additional waveguide layers are bonded to the second waveguide layer and/or the first waveguide layer to supplement the bonded waveguide stack. For example, each additional waveguide layer may be formed on the waveguide stack by depositing an additional bonding layer and bonding the respective additional waveguide layer in a bonding step. In certain aspects, the first waveguide layer can have a higher index of refraction than the second waveguide layer and/or other additional waveguide layers in the stack to produce index modulation at interfaces. For example, the refractive index of the waveguide layer can be reduced from the first waveguide layer by subsequent bonded waveguide layers. In some instances, the materials and thicknesses of the waveguide layers in the stack can selectively couple wavelengths of light passing through the layers in the waveguide.

At operation 1740 , a dicing process is performed to cut through the bonded waveguide stack and through the sacrificial material in one or more dicing lanes to form one or more individual layered waveguides. The dicing process may include laser ablation or other similar techniques for cutting through the waveguide stack.

In an alternate implementation, the sacrificial material may be deposited prior to depositing the bonding material at operation 1720 . In this implementation, the sacrificial material may act as a barrier during deposition of the bonding layer material, such as in a drop casting process or the like. During deposition of the bonding material, the sacrificial material acts as a barrier maintaining the bonding material in the region around the waveguide die and in the region inside the one or more dicing channels.

18 includes a diagram 1800 illustrating an example of a process flow depicting operations of a method of fabricating a layered waveguide according to an embodiment. The operations depicted in diagram 1800 are for purposes of illustration only and are not intended to be limiting. In various implementations, diagram 1800 may be modified to add additional operations, omit some operations, or change the order of operations. One or more operations described in diagram 1800 may be performed using, for example, one or more semiconductor manufacturing systems, such as ink jet systems, spin coating systems, chemical vapor deposition (CVD) systems, physical vapor deposition (PVD) systems , ion or plasma etching (eg, ion beam etching (IBE), plasma etching (PE), or reactive ion etching (RIE)) systems, and the like.

18 depicts a first waveguide layer 1810 (e.g., glass, silicon, silicon nitride, silicon carbide, LiNbO ₃ , TiO ₂ , GaN, AlN, SiC, CVD diamond, ZnS wafer) with one or more waveguide dies 1812 wait).

At operation 1855 , sacrificial material 1824 is formed on first waveguide layer 1810 in one or more dicing channels 1822 . In one implementation, an inkjet process or drop casting process or other additive process may be used to selectively deposit sacrificial material 1824 in one or more dicing channels 1822 . In another implementation, an ablation process may be used to form sacrificial material 1824 in one or more dicing channels 1822 . For example, a sacrificial material 1824 may be deposited on the first waveguide layer 1810 , and an etch process may be used to remove the sacrificial material outside of one or more dicing channels 1822 according to, for example, a dicing channel pattern. Before the etching process, the mask layer can be patterned on the first waveguide layer 1810 using a dicing channel pattern. The mask layer may comprise, for example, a metal or metal alloy material such as chromium or chromium oxide. The mask layer may have high resistance for dry etching, such as plasma etching. An etch process may then be performed to remove the sacrificial material from the first waveguide layer 1810 outside the one or more dicing channels 1822 and leave the sacrificial material 1824 in the one or more dicing channels 1822 . In one aspect, a photolithographic patterning process including positive tone development or negative tone development may be performed. The sacrificial material can be a material that is not normally bonded to the bonding layer. In one aspect, the sacrificial material is an inert polymeric material. In another aspect, the sacrificial material has orthogonal reactivity with the material of the bonding layer.

At operation 1860 , a layer 1820 of optically clear adhesive material or other bonding material is deposited on first waveguide layer 1810 in one or more regions bonded by the inner perimeter of sacrificial material 1824 within one or more dicing channels 1824 . For example, a drop casting process or similar process may be used to deposit bonding material (eg, OCA) in one or more regions, and the bonding material may be spread out until it reaches sacrificial material 1824 . The sacrificial material 1824 may act as a barrier to maintain the bonding material 1820 within the inner perimeter of the sacrificial material 1824 and within one or more regions within the cut channel 1822 . In the illustrated example, one or more regions surround waveguide die 1812 and are the outer regions above waveguide die 1812 . In another example, one or more regions are above the waveguide die 1812 . Bonding material 1820 may be formed as part of an additive process using the deposition techniques described herein. For example, an inkjet process or a drop casting process may be used to selectively deposit bonding material within one or more dicing channels 1822 .

At operation 1870 , the second waveguide layer 1830 is bonded to the first waveguide layer 1810 using the bonding layer 1820 in a bonding process to form a bonded waveguide stack 1835 . The bonding process may include UV curing and/or thermal bonding processes. In one implementation, the second waveguide layer 1830 may have a lower index of refraction than the first waveguide layer 1810 , for example, to produce index modulation.

At operation 1880 , a dicing process is performed to form one or more individual layered waveguides 1840 (also referred to as layered waveguide devices) from the bonded waveguide stack 1835 . The dicing process may include laser ablation or other similar techniques for cutting through bonded waveguide stack 1835 in one or more dicing channels 1822 . Although not shown, in another implementation, the fabrication depicted in FIG. 18 may also include forming in or on the exterior surfaces of the first waveguide layer 1810 and/or the second waveguide layer 1830 (e.g., by etch) one or more input gratings and/or output gratings. The input grating and/or the output grating may comprise, for example, inclined or vertical surface relief gratings.

In FIG. 18 , bonding material 1820 is disposed within the inner perimeter of one or more cut channels 1822 . In other implementations, bonding material 1820 may be disposed in one or more regions over one or more waveguide die 1812 . In one aspect, bonding material 1820 may not be disposed in any area outside of one or more cutting channels 1822 .

FIG. 19 includes a flowchart 1900 depicting an example of the operations of a method of fabricating a multilayer waveguide according to certain embodiments. Some of the operations may be similar to those depicted in FIG. 18 . The operations depicted in diagram 1900 are for purposes of illustration only and are not intended to be limiting. In various implementations, diagram 1900 may be modified to add additional operations, omit some operations, or change the order of operations. For example, although not shown, the process may also include forming one or more input and/or output gratings in or on the outer surface of the first waveguide layer and/or the second waveguide layer. The input grating and/or the output grating may comprise, for example, inclined or vertical surface relief gratings. One or more of the operations described in diagram 1900 may be performed using, for example, one or more semiconductor manufacturing systems, such as inkjet systems, spin coating systems, chemical vapor deposition (CVD) systems, physical vapor deposition (PVD) systems , ion or plasma etching (eg, ion beam etching (IBE), plasma etching (PE), or reactive ion etching (RIE)) systems, and the like.

At operation 1910 , a first waveguide layer (e.g., glass, silicon, silicon nitride, silicon carbide, _LiNbO3 , TiO _2. GaN, AlN, SiC, CVD diamond, ZnS wafer, etc.). In one implementation, the first waveguide layer may have one or more input and/or output gratings formed in or on the surface of the first waveguide layer.

At operation 1915 , a sacrificial material is formed on the first waveguide layer according to (eg, according to a cut-channel pattern) one or more cut channels. In one implementation, an inkjet process, drop casting process, or other selective additive process may be used to selectively deposit sacrificial material in one or more dicing channels, such as dicing channel 1822 shown in FIG. 18 . In another implementation, an ablation process may be used to form sacrificial material in one or more dicing channels. For example, a sacrificial material may be deposited on the first waveguide layer, and an etch process may be used to remove the sacrificial material outside one or more dicing channels according to the dicing channel pattern patterned on the first waveguide layer. Before the etching process, the mask layer can be patterned on the first waveguide layer using a dicing channel pattern. The mask layer may comprise, for example, a metal or metal alloy material such as chromium or chromium oxide. The mask layer may have high resistance for dry etching, such as plasma etching. An etch process may then be performed to remove sacrificial material from the first waveguide layer outside of the one or more scribed channels. In one aspect, a photolithographic patterning process including positive tone development or negative tone development may be performed. The sacrificial material can be a material that is not normally bonded to the bonding layer. In one aspect, the sacrificial material is an inert polymeric material. In another aspect, the sacrificial material has orthogonal reactivity with the material of the bonding layer.

At operation 1920 , a layer of optically clear adhesive material or other bonding material is deposited on the first waveguide layer in one or more regions bonded by the interior perimeter of the sacrificial material within the one or more cut channels. For example, a drop casting process or similar process can be used to deposit bonding material (eg, OCA) in one or more regions, and the bonding material can be spread out until reaching the sacrificial material. The sacrificial material can serve to maintain the bonding material within one or more regions of the perimeter of the sacrificial material and within the cut channel. In the illustrated example, the one or more regions surround the waveguide die and are the outer regions above the waveguide die. In another example, one or more regions are above the waveguide die. The bonding material can be formed as part of an additive process using the deposition techniques described herein. For example, an inkjet process or a drop casting process may be used to selectively deposit bonding material within one or more dicing channels.

At operation 1930 , the second waveguide layer is bonded to the first waveguide layer in a bonding process using a bonding material having one or more cut channels of sacrificial material to form a bonded waveguide stack. The bonding process may include UV curing and/or thermal bonding processes. In one implementation, the second waveguide layer may have a lower refractive index than the first waveguide layer. The respective indices of refraction of the first and second waveguide layers can be selected for the desired index modulation. A bonded waveguide stack may have one or more cut channels free or substantially free of bonding material. In this implementation, the bonding material is only disposed within the inner perimeter of the one or more cutting channels. In some cases, one or more dicing channels surround one or more waveguide dies and do not overlap or include portions of one or more waveguide dies. In other cases, one or more waveguide dies are in respective one or more dicing channels.

At an optional operation 1935 (depicted by dashed lines), one or more additional waveguide layers are bonded to the second waveguide layer and/or the first waveguide layer to supplement the bonded waveguide stack. For example, each additional waveguide layer can be formed on the waveguide stack by depositing an additional bonding layer and bonding the respective additional waveguide layer in a bonding step. In certain aspects, the first waveguide layer can have a higher index of refraction than the second waveguide layer and/or other additional waveguide layers in the stack to produce index modulation at interfaces. For example, the refractive index of the waveguide layer can be reduced from the first waveguide layer by subsequent bonded waveguide layers. In some instances, the materials and thicknesses of the waveguide layers in the stack can selectively couple wavelengths of light passing through the layers in the waveguide.

At operation 1940 , a dicing process is performed to cut through the bonded waveguide stack and through the sacrificial material in one or more dicing lanes to form one or more individual layered waveguides. The dicing process may include laser ablation or other similar techniques for cutting through the waveguide stack.

Although the illustrated examples of layered waveguides in FIGS. 14 , 16 , and 18 have dicing channels, the dicing channels are positioned in one or more dicing channels (eg, dicing channel 1422 and waveguide die 1412 , shown in FIG. Within the inner perimeter of dicing channel 1622 and waveguide die 1612 shown in FIG. 16 and dicing channel 1822 and waveguide die 1812 shown in FIG . 18 ), at a distance from the inner perimeter of one or more dicing channels, but The disclosure is not so limited. In other implementations, one or more waveguide dies may be positioned within one or more dicing channels.

In some aspects, the method of fabricating a multilayer waveguide described with respect to FIGS . 12 , 13 , 14 , 15 , 16 , 17 , 18 and 19 may also include the operation of forming one or more grating couplers to form a multilayer waveguide display .

20 is a simplified block diagram of an example electronic system 2000 for implementing an example near-eye display (eg, an HMD device) of some of the examples disclosed herein. Electronic system 2000 may be used as the electronic system of the HMD device described above or other near-eye display. In this example, the electronic system 2000 may include one or more processors 2010 and a memory 2020 . Processor 2010 may be configured to execute instructions for operating at several components, and may be, for example, a general purpose processor or microprocessor suitable for implementation within a portable electronic device. The processor 2010 can be communicatively coupled with a plurality of components within the electronic system 2000 . To achieve this communicative coupling, processor 2010 may communicate across bus 2040 with the other illustrated components. Bus 2040 may be any subsystem adapted to communicate data within electronic system 2000 . The bus 2040 may include a plurality of computer buses and additional circuitry to transfer data.

The memory 2020 can be coupled to the processor 2010 . In some embodiments, memory 2020 can provide both short-term and long-term storage, and can be divided into units. Memory 2020 may be: volatile, such as static random access memory (static random access memory; SRAM) and/or DRAM; and/or non-volatile, such as read-only memory (read-only memory; ROM) ), flash memory and the like. In addition, the memory 2020 may include a removable storage device, such as a secure digital (SD) card. The memory 2020 may provide storage of computer readable instructions, data structures, program modules, and other data for the electronic system 2000 . In some specific examples, the memory 2020 can be distributed into different hardware modules. A set of instructions and/or code may be stored on memory 2020 . The instructions may take the form of executable code executable by the electronic system 2000 , and/or may take the form of source code and/or installable code compiled on the electronic system 2000 and/or upon installation (eg, using any of a number of generally available compilers, installers, compression/decompression utilities, etc.), may take the form of executable code.

In some embodiments, the memory 2020 can store a plurality of application program modules 2022 to 2024 , and these application program modules can include any number of application programs. Examples of applications include: game applications, conference applications, video playback applications, or other suitable applications. Apps may include depth-sensing capabilities or eye-tracking capabilities. Application modules 2022 to 2024 may include specific instructions to be executed by processor 2010 . In some embodiments, some applications or parts of the application modules 2022 to 2024 can be executed by other hardware modules 2080 . In some embodiments, memory 2020 may additionally include secure memory, which may include additional security controls to prevent copying or other unauthorized access to secure information.

In some embodiments, the memory 2020 may include an operating system 2025 loaded therein. Operating system 2025 is operable to initiate execution of instructions provided by application modules 2022-2024 and /or manage other hardware modules 2080 , and interface with wireless communication subsystem 2030 , which may include one or more wireless transceivers. Operating system 2025 may be adapted to perform other operations across components of electronic system 2000 , including thread processing, resource management, data storage control, and other similar functionality.

Wireless communication subsystem 2030 may include, for example, infrared communication devices, wireless communication devices and/or chipsets (such as Bluetooth® devices, IEEE 802.11 devices, Wi-Fi devices, WiMax devices, cellular communication facilities, etc.) and/or similar communication interface. Electronic system 2000 may include one or more antennas 2034 for wireless communication as part of wireless communication subsystem 2030 or as a separate component coupled to any part of the system. Depending on desired functionality, the wireless communication subsystem 2030 may include separate transceivers to communicate with base transceiver stations and other wireless devices and access points, which may include communication with wireless wide-area networks (WWAN), Communication of different data networks and/or network types over a wireless local area network (WLAN) or a wireless personal area network (WPAN). A WWAN may be, for example, a WiMax (IEEE 802.16) network. The WLAN can be, for example, an IEEE 802.11x network. A WPAN can be, for example, a Bluetooth network, IEEE 802.17x, or some other type of network. The techniques described herein may also be used for any combination of WWAN, WLAN, and/or WPAN. Wireless communication subsystem 2030 may permit the exchange of data with a network, other computer systems, and/or any other devices described herein. Wireless communication subsystem 2030 may include components for using antenna 2034 and wireless link 2032 to transmit or receive data such as an identifier of the HMD device, location data, geographic maps, heat maps, photos or videos. The wireless communication subsystem 2030 , the processor 2010 , and the memory 2020 may together comprise at least a portion of one or more of the means for performing some of the functions disclosed herein.

Embodiments of the electronic system 2000 may also include one or more sensors 2090 . Sensors 2090 may include, for example, image sensors, accelerometers, pressure sensors, temperature sensors, proximity sensors, magnetometers, gyroscopes, inertial sensors (eg, a combination accelerometer and gyroscope) module), an ambient light detector, or any other similar module operable to provide a sensory output and/or receive a sensory input, such as a depth sensor or a position sensor. For example, in some embodiments, the sensor 2090 may include one or more inertial measurement units (IMU) and/or one or more position sensors. The IMU may generate calibration data indicating an estimated position of the HMD device relative to an initial position of the HMD device based on measurement signals received from one or more of the position sensors. The position sensor may generate one or more measurement signals in response to motion of the HMD device. Examples of position sensors may include, but are not limited to, one or more accelerometers, one or more gyroscopes, one or more magnetometers, another suitable type of sensor to detect motion, error for an IMU Calibration of a type of sensor, or some combination thereof. The position sensors may be located external to the IMU, internal to the IMU, or some combination thereof. At least some sensors may use structured light patterns for sensing.

The electronic system 2000 can include a display module 2060 . The display module 2060 can be a near-eye display, and can present information such as images, videos, and various instructions from the electronic system 2000 to the user in a graphical manner. This information may originate from one or more application modules 2022-2024 , virtual reality engine 2026 , one or more other hardware modules 2080 , combinations thereof, or be used to interpret graphical content for the user (eg, by by any other suitable component of Operating System 2025 ). The display module 2060 may use liquid crystal display (liquid crystal display; LCD) technology, LED technology (including, for example, OLED, ILED, mLED, AMOLED, TOLED, etc.), light emitting polymer display (light emitting polymer display; LPD) technology, or some other display technologies.

The electronic system 2000 can include a user input/output module 2070 . The user input/output module 2070 can allow the user to send action requests to the electronic system 2000 . An action request may be a request to perform a specific action. For example, an action request may start or end an application or perform a specific action within the application. The user input/output module 2070 may include one or more input devices. Example input devices may include touch screens, trackpads, microphones, buttons, dials, switches, keyboards, mice, game controllers, or devices for receiving action requests and communicating received action requests to the electronic system 2000 . any other suitable device. In some embodiments, the user input/output module 2070 can provide tactile feedback to the user according to commands received from the electronic system 2000 . For example, haptic feedback may be provided when an action request is received or has been performed.

The electronic system 2000 may include a camera 2050 , and the camera 2050 may be used to take pictures or videos of the user, for example, to track the position of the user's eyes. The camera 2050 can also be used to take pictures or videos of the environment, such as for VR, AR or MR applications. The camera 2050 may include, for example, a complementary metal-oxide-semiconductor (CMOS) image sensor with millions or tens of millions of pixels. In some implementations, camera 2050 may include two or more cameras that may be used to capture 3D images.

In some specific examples, the electronic system 2000 may include a plurality of other hardware modules 2080 . Each of the other hardware modules 2080 may be a physical module within the electronic system 2000 . While each of the other hardware modules 2080 may be permanently configured as a configuration, some of the other hardware modules 2080 may be temporarily configured to perform specific functions or be temporarily enabled. Examples of other hardware modules 2080 may include, for example, audio output and/or input modules (eg, microphones or speakers), near field communication (NFC) modules, rechargeable batteries, battery management systems, wired / wireless battery charging system, etc. In some embodiments, one or more functions of other hardware modules 2080 can be implemented in software.

In some specific examples, the memory 2020 of the electronic system 2000 can also store the virtual reality engine 2026 . The virtual reality engine 2026 can execute applications in the electronic system 2000 and receive position information, acceleration information, velocity information, predicted future position, or some combination thereof of the HMD device from various sensors. In some embodiments, information received by the virtual reality engine 2026 may be used to generate signals (eg, display commands) for the display module 2060 . For example, if the received information indicates that the user has looked to the left, the virtual reality engine 2026 can generate content for the HMD device that reflects the user's movement in the virtual environment. Additionally, the virtual reality engine 2026 can perform in-application actions in response to action requests received from the user input/output module 2070 and provide feedback to the user. The feedback provided may be visual, auditory or tactile feedback. In some implementations, the processor 2010 may include one or more graphics processing units (graphic processing units; GPUs) of the executable virtual reality engine 2026 .

In various implementations, the hardware and modules described above can be implemented on a single device or multiple devices that can communicate with each other using wired or wireless connections. For example, in some implementations, some components or modules such as the GPU, virtual reality engine 2026 , and applications (eg, tracking applications) may be implemented on a console separate from the head mounted display device. In some implementations, a console can connect to or support more than one HMD.

In alternative configurations, different and/or additional components may be included in electronic system 2000 . Similarly, the functionality of one or more of the components may be distributed among the components in a different manner than that described above. For example, in some embodiments the electronic system 2000 may be modified to include other system environments, such as an AR system environment and/or a MR environment.

The methods, systems, and devices discussed above are examples. Various embodiments may omit, substitute, or add various procedures or components as appropriate. For example, in alternative configurations, the methods described may be performed in an order different from that described, and/or various stages may be added, omitted, and/or combined. Furthermore, features described with respect to certain embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments can be combined in a similar manner. Furthermore, technology evolves, and thus many of the elements are examples that do not limit the scope of the disclosure to those particular examples.

Specific details are given in the description to provide a thorough understanding of specific examples. However, specific examples may be practiced without such specific details. For example, well-known circuits, processes, systems, structures and techniques have been shown without unnecessary detail in order not to obscure the particular example. This description provides example specifics only, and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the foregoing descriptions of the specific examples will provide those of ordinary skill in the art with a description that can enable various specific examples to be practiced. Various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the disclosure.

Additionally, some embodiments are described as processes depicted as flowcharts or block diagrams. Although each may describe operations as sequential processes, many operations may be performed in parallel or simultaneously. Additionally, the order of operations can be reconfigured. Processes may have additional steps not included in the figures. Furthermore, embodiments of the methods may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. When implemented in software, firmware, middleware or microcode, the code or segments of written code to perform associated tasks may be stored in a computer-readable medium such as a storage medium. A processor can perform associated tasks.

It will be apparent to those skilled in the art that substantial changes may be made according to particular requirements. For example, custom or special purpose hardware may also be used, and/or particular elements may be implemented in hardware, software (including portable software, such as applets, etc.), or both. Additionally, connections to other computing devices, such as network input/output devices, may be employed.

Referring to the figures, a component that may include memory may include a non-transitory machine-readable medium. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any storage medium that participates in providing data that causes a machine to operate in a specific manner. In the specific examples provided above, various machine-readable media can be involved in providing instructions/code to a processing unit and/or other device(s) for execution. Additionally or alternatively, a machine-readable medium may be used to store and/or carry such instructions/code. In many implementations, the computer-readable medium is a physical and/or tangible storage medium. Such media may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Common forms of computer readable media include, for example, magnetic and/or optical media, such as compact disks (CDs) or digital versatile disks (digital versatile disks (DVDs); punched cards; paper tape; Any other physical media; RAM; programmable read-only memory (PROM); erasable programmable read-only memory (EPROM); FLASH-EPROM; any Other memory chips or cartridges; carrier waves as described below; any other medium from which a computer can read instructions and/or code. A computer program product may include code and/or machine-executable instructions which may represent a program, function, subroutine, program, routine, application (App), subroutine formula, module, package, class, or any combination of instructions, data structures, or program statements.

Those of ordinary skill in the art will appreciate that information and signals used to convey the messages described herein can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

As used herein, the terms "and" and "or" may include a variety of meanings which are also expected to depend, at least in part, on the context in which such terms are used. Typically, "or" when used in relation to a list, such as A, B, or C, is intended to mean A, B, and C (here used in an inclusive sense), and A, B, or C (here used in an exclusive sense) . In addition, as used herein, the term "one or more" may be used to describe any feature, structure or characteristic in the singular or may be used to describe some combination of features, structures or characteristics. It should be noted, however, that this is merely an illustrative example and that claimed subject matter is not limited to this example. Furthermore, the term "at least one of" if used in relation to a list (such as A, B or C) may be interpreted to mean any combination of A, B and/or C, such as A, AB, AC, BC, AA, ABC, AAB, AABBCCC, etc.

Furthermore, while certain specific examples have been described using specific combinations of hardware and software, it should be recognized that other combinations of hardware and software are possible. Certain embodiments may be implemented in hardware only or in software only, or using a combination thereof. In one example, the software can be implemented by a computer program product containing computer code or instructions executable by one or more processors for performing the tasks described in this disclosure. Any or all of the steps, operations or processes, wherein the computer program can be stored on a non-transitory computer readable medium. The various processes described herein may be implemented in any combination on the same processor or on different processors.

Where a device, system, component, or module is described as being configured to perform certain operations or functions, it may be possible, for example, by designing electronic circuits to perform the operations, by programming programmable electronic circuits (such as micro processor) to perform operations (such as by executing computer instructions or code, or a processor or core programmed to execute code or instructions stored on a non-transitory memory medium), or any combination thereof this configuration. Processes may communicate using a variety of techniques, including but not limited to known techniques for inter-process communication, and different pairs of processes may use different technologies, or the same pair of processes may use different technologies at different times.

Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than a restrictive sense. It will be apparent, however, that additions, subtractions, deletions, and other modifications and changes may be made to the specification and drawings without departing from the broader spirit and scope as set forth in the claims. Thus, while certain embodiments have been described, such embodiments are not intended to be limiting. Various modifications and equivalents are within the scope of the following patent applications.

100: Artificial Reality System Environment 110: Console 112: App store 114:Headphone Tracking Module 116: Artificial Reality Engine 118:Eye Tracking Module 120: near-eye display 122: display electronics 124: Display optics 126: Locator 128: Position sensor 130:Eye Tracking Unit 132: Inertial measurement unit 140: input/output interface 150: external imaging device 200: HMD device 220: subject 223: bottom side 225: front side 227: left side 230: head strap 300: near-eye display 305: frame 310: Display 330: illuminator 340: high resolution camera 350a: sensor 350b: sensor 350c: sensor 350d: sensor 350e: sensor 400: Optical see-through augmented reality system 410:Projector 412: image source 414:Projector optics 415: Combiner 420: Substrate 430: Input coupler 440: output coupler 450: light 460: extracted light 490: eyes 495: Human eye window 500: near-eye display device 510: light source 512: red light emitter 514: Green emitter 516:Blue light emitter 520: Projection optics 530: waveguide display 532:Coupler 540: light source 542: red light emitter 544: Green emitter 546:Blue light emitter 550: near-eye display 560: Freeform Optics 570: Scan mirror 580:Waveguide display 582:Coupler 590: eyes 600: waveguide display 605: Single input pupil 610: Substrate 612: first surface 614: second surface 620: Input coupler 630: the first output raster 632: line 634: line 640: second output raster 650: Exit area 660: Gathered exit pupil 662: individual exit pupil 700:Waveguide display 710: waveguide 720: tilted grating 722: Ridge 724: Groove 726: front edge 728: rear edge 730: Outer coating 800:Waveguide display 810: waveguide 820: grating coupler 830: external light 832:0 order diffracted light 834:-1st order diffracted light 840: display light 842:0 order diffracted light 844:-1st order diffracted light 900:Waveguide display 901: Exemplary Waveguide Display 910: single layer waveguide 911: Layered waveguide 915: free space 920: grating coupler 930: external light 940: transparent waveguide layer 950: the first transparent waveguide layer 960: the second waveguide layer 1000: waveguide display 1001: single layer waveguide 1002:Layered waveguide display 1003: layered waveguide 1010: Substrate 1012: The first waveguide layer 1020: grating 1022: input raster 1024: input raster 1030: output raster 1032: output raster 1040: output raster 1042: output raster 1050: the second waveguide layer 1060: first beam 1062: Second beam 1100: Multiple Waveguide Display 1101: layered waveguide 1102: Multilayer waveguide display 1103: layered waveguide 1110: the first waveguide layer 1112: The first waveguide layer 1120: input raster 1122: input raster 1124: input raster 1126: input raster 1130: output raster 1132: output raster 1140: output raster 1142: output raster 1150: the second waveguide layer 1152: the second waveguide layer 1160: The third waveguide layer 1162: The third waveguide layer 1170: The fourth waveguide layer 1180: The fifth waveguide layer 1200: Figure 1210: the first waveguide layer 1212:Waveguide grain 1220: bonding material layer 1230: the second waveguide layer 1235: waveguide stack 1240: individual waveguide device 1260: Operation 1270: Operation 1280: Operation 1300: flow chart 1310: Operation 1320: Operation 1330: Operation 1335: Operation 1340: Operation 1400: Figure 1410: The first waveguide layer 1412: waveguide grain 1420: Bonding material layers 1422: cutting channel 1430: Second waveguide layer 1435: waveguide stack 1440: Individual layered waveguides 1460: Operation 1470: Operation 1480: Operation 1500: Flowchart 1510: Operation 1520: Operation 1530: Operation 1535: Operation 1540: Operation 1600: Figure 1610: The first waveguide layer 1612: waveguide grain 1620: Bonding material layers 1622: cutting channel 1624: sacrificial material 1630: Second waveguide layer 1635: Waveguide Stacking 1640: Individual layered waveguides 1660: Operation 1665: Operation 1670: Operation 1680: Operation 1700: Flowchart 1710: Operation 1720: Operation 1725: operation 1730: Operation 1735: operation 1740: Operation 1800: Figure 1810: First waveguide layer 1812:Waveguide Die 1820: Layers of bonding material 1822: Cutting Channel 1824: Sacrificial material 1830: Second waveguide layer 1835: Waveguide stacking 1840: Individual layered waveguides 1855: Operation 1860: Operation 1870: Operation 1880: Operation 1900: Flowchart 1910: Operation 1915: Operation 1920: Operation 1930: Operation 1935: Operation 1940: Operation 2000: Electronic systems 2010: Processor 2020: Memory 2022: App Mods 2024: App Mods 2025: Operating system 2026: Virtual reality engine 2030: Subsystems 2032: Wireless link 2034: Antenna 2040: busbar 2050: Camera 2060: display module 2070: User Input/Output Module 2080: hardware module 2090: sensor 2101: waveguide stack 2102: Multilayer waveguide d: width p: grating period α: tilt angle β: tilt angle λ:wavelength

Illustrative specific examples are described in detail below with reference to the following figures. [ FIG. 1 ] is a simplified block diagram of an example of an artificial reality system environment including a near-eye display, according to certain embodiments. [ FIG. 2 ] Is a perspective view of an example of a near-eye display in the form of a head mounted display device for implementing some of the examples disclosed herein. [ FIG. 3 ] Is a perspective view of an example of a near-eye display in the form of a pair of glasses for implementing some of the examples disclosed herein. [ FIG. 4 ] illustrates an example of an optical see-through augmented reality system including a waveguide display according to certain embodiments. [ FIG. 5A ] illustrates an example of a near-eye display device including a waveguide display according to certain embodiments. [ FIG. 5B ] illustrates an example of a near-eye display device including a waveguide display according to some embodiments. [ FIG. 6A ] Illustrates an example of an optical see-through augmented reality system including a waveguide display and a surface relief grating for exit pupil expansion, according to certain embodiments. [ FIG. 6B ] illustrates an example of a human eye window including a two-dimensionally replicated exit pupil, according to certain embodiments. [ FIG. 7 ] illustrates an example of a slanted grating in a waveguide display according to some embodiments. [ FIG. 8 ] Illustrates propagation of display light and external light in an example of a waveguide display according to some embodiments. [ FIG. 9A ] illustrates propagation of display light in an example of a waveguide display according to certain embodiments. [ FIG. 9B ] Illustrates the propagation of display light in an example of a waveguide display with multilayer waveguides according to certain embodiments. [ FIG. 10A ] Illustrates the propagation of display light in an example of a waveguide display with multilayer waveguides according to certain embodiments. [ FIG. 10B ] Illustrates the propagation of display light in an example of a waveguide display with multilayer waveguides according to certain embodiments. [ FIG. 11A ] Illustrates the propagation of display light in an example of a waveguide display with multilayer waveguides according to certain embodiments. [ FIG. 11B ] Illustrates the propagation of display light in an example of a waveguide display with multilayer waveguides according to certain embodiments. [ FIG. 12 ] is a diagram illustrating an example of a process flow depicting operations of a method of manufacturing a multilayer waveguide according to certain embodiments. [ FIG. 13 ] is a flowchart depicting the operation of an example of a method of fabricating a multilayer waveguide according to certain embodiments. [ FIG. 14 ] is a diagram illustrating an example of a process flow depicting operations of a method of manufacturing a layered waveguide according to certain embodiments. [ FIG. 15 ] is a flowchart depicting the operation of an example of a method of manufacturing a layered waveguide according to certain embodiments. [ FIG. 16 ] is a diagram illustrating an example of a process flow depicting operations of a method of manufacturing a layered waveguide according to certain embodiments. [ FIG. 17 ] is a flowchart depicting the operation of an example of a method of manufacturing a layered waveguide according to certain embodiments. [ FIG. 18 ] is a diagram illustrating an example of a process flow depicting operations of a method of manufacturing a layered waveguide according to certain embodiments. [ FIG. 19 ] is a flowchart depicting the operation of an example of a method of manufacturing a layered waveguide according to certain embodiments. [ FIG. 20 ] Is a simplified block diagram of an exemplary electronic system for implementing an exemplary near-eye display of some of the examples disclosed herein. [ FIG. 21A ] is a photograph of a bonded waveguide stack fabricated according to an example. [ FIG. 21B ] is a photograph of a waveguide stack fabricated according to an example. The figures depict specific examples of the disclosure for purposes of illustration only. Those skilled in the art will readily recognize from the following description that alternative embodiments of the illustrated structures and methods may be used without departing from the principles or laudable benefits of the present disclosure. In the figures, similar components and/or features may have the same reference label. In addition, various components of the same type may be distinguished by the use of a dash after the reference label and a second label to distinguish among similar components. If only a first reference label is used in the specification, the description applies to any of similar components having the same first reference label independently of the second reference label.

1300: flow chart

1310: Operation

1320: Operation

1330: Operation

1335: Operation

1340: Operation

Claims (29)

A method of fabricating one or more multilayer waveguides, the method comprising: receiving or forming a first waveguide layer; forming a bonding layer with one or more dicing channels on the first waveguide layer; bonding a second waveguide layer to the first waveguide layer to form a bonded waveguide stack; and The bonded waveguide stack is cut through the bonded waveguide stack along the one or more cutting channels to form one or more multilayer waveguides. The method of claim 1, wherein the bonding layer is formed by depositing an optically transparent adhesive material. The method of claim 2, wherein the one or more cutting channels do not contain the optically clear adhesive material. The method of claim 1, wherein forming the bonding layer comprises inkjet depositing a two-dimensional array of droplets of an optically clear adhesive material on the first waveguide layer. The method of claim 4, wherein the material forming the optically clear adhesive comprises a base resin, and the base resin comprises a material selected from the group consisting of: acrylate, epoxy, vinyl, mercaptan, allyl base, vinyl ether, allyl ether, epoxy acrylate, urethane acrylate, and acrylic polyester. The method according to claim 5, wherein the optically transparent adhesive material further comprises nanoparticles containing metal oxides. The method of claim 1, further comprising depositing a sacrificial material in the one or more dicing channels. The method of claim 7, wherein cutting through the bonded waveguide stack includes cutting through the sacrificial material. The method of claim 1, wherein the one or more dicing channels surround one or more waveguide dies in the first waveguide layer. The method of claim 1, wherein the one or more dicing channels are formed by: (i) patterning the bonding layer using photolithography or (ii) by selecting outside the one or more dicing channels An optically clear adhesive material is selectively deposited to form the bonding layer. The method according to claim 1, wherein one or both of the second waveguide layer and the bonding layer has a refractive index which is the same as or lower than that of the first waveguide layer. The method according to claim 1, further comprising forming one or more input gratings and/or output gratings in the first waveguide layer. The method of claim 1, further comprising forming one or more additional waveguide layers on the bonded waveguide stack, each additional waveguide layer being formed by: depositing an optically clear adhesive material; and The additional waveguide layer is bonded. The method of claim 1, wherein cutting through the bonded waveguide stack comprises applying laser ablation along the one or more cutting channels. A method of making one or more multilayer waveguide displays, the method comprising: receiving or forming a first waveguide layer having one or more gratings; forming a layer of optically clear adhesive material having one or more cut channels on the first waveguide layer; bonding a second waveguide layer to the first waveguide layer to form a bonded waveguide stack; cutting through the bonded waveguide stack along the one or more cutting channels to form one or more multilayer waveguides; and The one or more multilayer waveguide displays are formed using the one or more multilayer waveguides. The method of claim 15, further comprising depositing a sacrificial material in at least a portion of the one or more dicing channels. The method of claim 15, wherein the one or more cutting channels do not contain an optically clear adhesive material. One or more multilayer waveguides manufactured by: receiving or forming a first waveguide layer; forming a layer of optically clear adhesive material on the first waveguide layer, the layer of optically clear adhesive material having one or more cut channels free of optically clear adhesive material; bonding a second waveguide layer to the first waveguide layer to form a bonded waveguide stack; and The bonded waveguide stack is cut through the bonded waveguide stack along the one or more cutting channels to form the one or more multilayer waveguides. One or more multilayer waveguides as claimed in claim 18, wherein the multilayer waveguides are further fabricated by depositing sacrificial material at the one or more dicing channels. The one or more multilayer waveguides of claim 18, wherein forming the layer of optically clear adhesive material comprises inkjet depositing droplets of optically clear adhesive material on the first waveguide layer. One or more multilayer waveguides as claimed in claim 18, wherein one or both of the second waveguide layer and the optically transparent adhesive material layer have a refractive index that is the same as or lower than that of the first waveguide layer refractive index. A multilayer waveguide display comprising: A layered waveguide fabricated by cutting through a bonded waveguide stack along one or more dicing channels in at least one of a plurality of waveguide layers of the bonded waveguide stack, wherein the one or more dicing channels do not contain bonded waveguides materials; and One or more grating couplers configured to diffractively couple display light into or out of the layered waveguide and/or to refractively transmit ambient light through the layered waveguide. The multilayer waveguide display of claim 22, wherein the one or more cut lines comprise sacrificial material. The multilayer waveguide display of claim 23, wherein the sacrificial material is deposited prior to depositing the bonding layer on the first waveguide layer of the plurality of waveguide layers of the bonded waveguide stack. A method of fabricating one or more multilayer waveguides, the method comprising: receiving or forming a first waveguide layer; depositing sacrificial material in one or more regions along one or more dicing channels on the first waveguide layer; depositing a bonding material at least partially within an interior perimeter of the one or more regions with the sacrificial material; bonding a second waveguide layer to the first waveguide layer with the bonding material to form a bonded waveguide stack; and The bonded waveguide stack is cut through the bonded waveguide stack along the one or more cutting channels to form one or more multilayer waveguides. The method of claim 25, wherein the bonding material is an optically clear adhesive material and the one or more cutting channels do not contain the optically clear adhesive material. The method of claim 25, wherein depositing the bonding material comprises inkjet depositing a two-dimensional array of droplets of an optically clear adhesive material on the first waveguide layer. The method according to claim 25, wherein one or both of the second waveguide layer and the bonding material has a refractive index which is the same as or lower than that of the first waveguide layer. The method of claim 25, further comprising forming one or more gratings at an outer surface of at least one of the first waveguide layer and the second waveguide layer.

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