JP2023041678A - Improved manufacturing for virtual and augmented reality system and component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide improved manufacturing for a virtual and augmented reality system and a component.

SOLUTION: An improved diffraction structure for a 3D display system is disclosed. The improved diffraction structure includes an intermediate layer between a waveguide substrate and an upper grid surface. The upper grid surface comprises a first material corresponding to a first refractive index value, a lower layer comprises a second material corresponding to a second refractive index value, and the substrate comprises a third material corresponding to a third refractive index value. According to additional embodiments, an improved approach is provided for mounting the deposits of a transfer material on the substrate, which enables very precise distribution and deposition of different transfer patterns on a given number of substrate surfaces.

SELECTED DRAWING: Figure 19

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present disclosure relates to virtual and augmented reality imaging and visualization systems.

Modern computing and display technology is leading to so-called "virtual reality", in which digitally reproduced images, or portions thereof, are presented to the user in a manner that appears to be real or can be perceived as such. Or promoting the development of systems for "augmented reality" experiences. Virtual reality, or "VR" scenarios, typically involve the presentation of digital or virtual image information without transparency to other actual, real-world visual inputs. Augmented reality, or "AR" scenarios, typically involve the presentation of digital or virtual image information as an extension of the user's visualization of the real world around them. For example, referring to FIG. 1, an augmented reality scene (4) is depicted in which a user of AR technology is shown a real-world scene featuring people, trees, a building as a background, and a concrete platform (1120). A park-like setting (6) is visible. In addition to these items, users of AR technology can also see a robot statue (1110) standing on a real-world platform (1120) and a flying cartoon-like avatar character (1110) that looks like an anthropomorphic bumblebee. 2) are "seen", but these elements (2, 1110) do not exist in the real world. In conclusion, the human visual perceptual system is very complex, and VR or AR technologies facilitate a comfortable, natural-feeling and rich presentation of virtual image elements among other virtual or real-world image elements. is difficult to generate.

There are a number of challenges when presenting 3D virtual content to users of AR systems. A premise of presenting 3D content to users involves the generation of multiple depth perceptions. In other words, it may be desirable for some virtual content to appear closer to the user, while other virtual content appears to occur further away. Therefore, to achieve 3D perception, AR systems should be configured to deliver virtual content in different focal planes to the user.

For a 3D display to provide a true sense of depth, and more specifically a simulated sense of surface depth, for each point in the display's field of view, generate an accommodative response corresponding to its virtual depth. It is desirable to If the accommodation response to a display point does not correspond to the virtual depth of that point, which is determined by convergence and stereoscopic binocular depth cues, the human visual system experiences accommodative collisions and produces unstable results. Absence of vision, adverse eye strain, headaches, and accommodation information can result in an almost complete lack of surface depth.

Therefore, there is a need for improved techniques for implementing 3D displays that solve these and other problems of conventional approaches. The systems and techniques described herein are configured to work with typical human visual configurations and address these challenges.

Embodiments of the present invention are directed to devices, systems and methods for facilitating virtual and/or augmented reality interactions for one or more users.

An augmented reality (AR) display system for delivering augmented reality content to a user, according to some embodiments, includes an image source for providing one or more frames of image data and one or more frames of image data. and a diffractive optical element (DOE) for receiving light associated with one or more frames of image data and directing the light to a user's eye. , the DOE comprises a waveguide substrate corresponding to the waveguide refractive index, a surface grating, and an intermediate layer (also referred to herein as the "lower layer") disposed between the waveguide substrate and the surface grating. ), the lower layer comprising a DOE corresponding to the lower layer diffraction index different from the waveguide index.

According to some embodiments of the invention, a diffractive structure is employed for a DOE that includes an underlying layer between the waveguide substrate and the upper grating surface. The upper grating surface comprises a first material corresponding to a first refractive index value, the lower layer comprises a second material corresponding to a second refractive index value, and the substrate comprises a third refractive index value. A corresponding third material is provided.

Any combination of the same or different materials may be employed to implement each of these portions of the structure, for example all three materials are different (and all three materials correspond to different refractive index values). ), or two of the layers share the same material (e.g., two of the three materials are the same and thus have a common refractive index that differs from the refractive index value of the third material). share values). Any suitable set of materials may be used to implement any layer of the improved diffractive structure.

Various combinations are therefore available, where a lower layer of one index of refraction is combined with an upper grating of another index of refraction, along with a substrate of a third index of refraction, and adjustment of their relative values is dependent on the angle of incidence provides many variations in the dependence of diffraction efficiency on . A layered waveguide with layers of different refractive indices is presented. Various combinations and permutations are presented along with associated performance data to demonstrate functionality. Advantages include an increase in angle, which provides an increase in output angle with the grating and therefore an increase in field of view with the eyepiece. Additionally, the ability to counteract the normal decrease in diffraction efficiency with angle is functionally beneficial.

According to additional embodiments, improved approaches are provided for implementing deposition of transfer material onto a substrate as well as transfer of transfer material into patterns for implementing diffraction. These approaches allow very precise distribution, deposition and/or formation of different transfer materials/patterns onto any number of substrate surfaces. According to some embodiments, patterned distribution of transfer material (eg, patterned inkjet distribution) is performed to implement deposition of transfer material onto a substrate. This approach, using patterned inkjet distributions, allows very precise volumetric control over the material to be deposited. Additionally, this approach can serve to provide a smaller, more uniform substrate beneath the grating surface.

In some embodiments, a template is provided having a first set of deeper depth structures with a second set of shallower depth structures. When depositing transfer material on the transfer receiving side, a relatively larger volume of transfer material is deposited corresponding to the deeper depth features of the template. Additionally, a relatively smaller volume of transfer material is deposited corresponding to the shallower depth features of the template. This approach allows simultaneous deposition of different thicknesses of material so that different features are formed on the transfer receiving side. This approach is intended to produce distributions that are intentionally non-uniform for structures with different depths and/or feature parameters, e.g., feature structures are on the same substrate and have different thicknesses. can be This can be used, for example, to create spatially distributed volumes of transfer material that allow simultaneous transfer of structures of variable depth with the same underlayer thickness.

Some embodiments relate to approaches for implementing simultaneous deposition of multiple types of transfer materials onto a substrate. This allows materials with optical properties to be deposited simultaneously over multiple portions of the substrate at one time. This approach also provides the ability to tune local areas associated with specific functions (e.g., to act as incoupling gratings, orthogonal pupil expander (OPE) gratings, or exit pupil expander (EPE) gratings). offer. Different types of materials can include the same material with different optical properties (eg, two versions of the same material with different refractive indices) or two entirely different materials. Any optical property of the material, such as refractive index, opacity, and/or absorbance, can be considered and selected when employing this technique.

According to another embodiment, multi-sided transfer may be employed to transfer to multiple sides of the optical structure. This allows transfer to occur on different sides of the optical element, implementing multiplexing of functions throughout the base layer volume. In this way different eyepiece functions can be implemented without adversely affecting the grating structure function. A first template can be used to generate a transfer on the substrate/transfer-receiving side "A" and to form a first pattern with a first material on side A of the structure. Another template can be used to produce a second transfer on side "B" of the same substrate, which forms a second pattern with a second material on side B of the substrate. Sides A and B can have the same or different patterns and/or can have the same or different types of materials.

Additional embodiments relate to multi-layer overtransfer and/or multi-layer separation/offset substrate integration. In either/both of these approaches, the previously transferred pattern can be jetted and printed again. Adhesive can be jetted onto the first layer, a second substrate is bonded to it (possibly with air gaps), and a subsequent jetting process deposits and transfers onto the second substrate. can be done. A series of transferred patterns can be joined together sequentially in a roll-to-roll process. Note that the approach of implementing multi-layer overtransfer can be used with or instead of the multi-layer separation/offset substrate integration approach. For multi-layer transfer, a first transfer material is deposited on the substrate and transferred, followed by deposition of a second transfer material, transferring both the first transfer material and the second transfer material. can result in a composite multi-layer structure with For multi-layer separation/offset substrate integration, both first substrate 1 and second substrate 2 may be transferred with a transfer material, after which substrates 1 and 2 may, in one embodiment, possibly leave an air gap. It can be pinched and bonded with offset features (also transferred) provided between the active structures of substrate 2 and the backside of substrate 1 . Transferred spacers can be used to create voids.

According to yet another embodiment, an approach is disclosed for implementing variable volume deposition of material distributed across a substrate, which may rely on a priori knowledge of surface non-uniformity. This corrects for surface non-uniformities in the substrate that can lead to undesirable parallelism and poor optical performance. Variable volume deposition of transfer material can be employed to provide a horizontal distribution of the transfer material to be deposited, independent of the underlying topography or physical feature set. For example, the substrate is pulled flat by a vacuum chuck and in situ measurements can be made to assess surface height using, for example, low coherence or laser-based contact measurement probes. The dispensed volume of transfer material can be varied according to the measured data, resulting in a more uniform layer upon reproduction. Any type of non-uniformity such as thickness variations and/or the presence of depressions, peaks, or other anomalies or features associated with localized locations on the substrate may also be addressed by this embodiment of the invention.

Note that any of the aforementioned embodiments can be combined together. Furthermore, additional and other objects, features, and advantages of the present invention are set forth in the detailed description, drawings, and claims.
For example, the present application provides the following items.
(Item 1)
A method of manufacturing a diffractive optical element, comprising:
depositing one or more sets of materials on a substrate;
identifying a template, the template having a transfer pattern formed thereon;
transferring the transfer pattern into the set of one or more materials on the substrate using the template;
The method, wherein the transfer pattern comprises a diffraction pattern for the diffractive optical element.
(Item 2)
the set of one or more materials on the substrate comprises a first portion of material and a second portion of material;
the template comprises a first set of depth structures and a second set of depth structures, the first set of depth structures having a different depth than the second set of depth structures;
The transfer pattern comprises a first pattern and a second pattern,
simultaneously forming the first pattern and the second pattern on the substrate, the template forming the first pattern with the first set of depth structures on the first portion of the material; , wherein the template transfers the second pattern with the second set of depth structures onto the second portion of the material.
(Item 3)
3. The method of any of items 1-2, wherein the first pattern corresponds to a first grating pattern and the second pattern corresponds to a second grating pattern.
(Item 4)
4. The method of any of items 1-3, wherein the first and second portions of the material correspond to a non-uniform distribution of the material over the substrate.
(Item 5)
5. The method of any of items 1-4, wherein the substrate forms a uniform thickness underlayer and the first and second patterns form variable depth structures on the uniform thickness underlayer.
(Item 6)
The set of one or more materials on the substrate comprises a first portion of material and a second portion of material, wherein the first portion of material is different than the second portion of material. A method according to any one of items 1 to 5, having optical properties.
(Item 7)
7. The method of any of items 1-6, wherein the different optical properties between the first portion of the material and the second portion of the material correspond to different refractive indices, opacities or absorbances. .
(Item 8)
8. The method of any of items 1-7, wherein the first portion of the material is deposited over the second portion of the material prior to transfer.
(Item 9)
The set of one or more materials on the substrate comprises a first portion of material and a second portion of material, the first portion of material on a first side of the substrate. , the second portion of the material is on a second surface of the substrate;
transferring a first pattern into a first portion of the material on the first side of the substrate;
transferring a second pattern into a second portion of the material on the second side of the substrate;
A method according to any one of items 1-8.
(Item 10)
10. The method of any of items 1-9, wherein the first pattern is different than the second pattern.
(Item 11)
11. The method of any of items 1-10, wherein the first portion of material is a different material than the second portion of material.
(Item 12)
The set of one or more materials on the substrate comprises a first portion of material and a second portion of material, wherein the first portion of material deposits the second portion of material. 12. The method of any of items 1-11, previously deposited and transferred.
(Item 13)
13. A method according to any of items 1 to 12, wherein transfer is performed onto said second portion of said material.
(Item 14)
14. The method of any of items 1-13, wherein the first substrate with a first transferred pattern is superimposed on the second substrate with a second transferred pattern.
(Item 15)
15. The method of any of items 1-14, wherein the first substrate with the first transferred pattern is bonded to the second substrate with the second transferred pattern.
(Item 16)
16. Any of items 1-15, wherein spacers form a gap between the first substrate having the first transferred pattern and the second substrate having the second transferred pattern. The method described in .
(Item 17)
17. The method of any of items 1-16, wherein variable levels of the set of one or more materials are deposited on the substrate.
(Item 18)
18. The method of any of items 1-17, wherein the variable levels of the set of one or more materials deposited on the substrate are identified by measuring variability in surface uniformity of the substrate. .
(Item 19)
19. The method of any of items 1-18, wherein the set of one or more materials is deposited on the substrate by inkjet deposition.
(Item 20)
A diffractive optical element formed using the method of any of items 1-19.

FIG. 1 illustrates an augmented reality (AR) user's view through a wearable AR user device in one illustrated embodiment. FIG. 2 illustrates a conventional stereoscopic 3D simulation display system. FIG. 3 illustrates an improved approach for implementing a stereoscopic 3D simulation display system, according to some embodiments of the invention. 4A-4D illustrate various systems, subsystems, and components to address the goal of providing a high quality, pleasingly perceived display system for human VR and/or AR. 4A-4D illustrate various systems, subsystems, and components to address the goal of providing a high quality, pleasingly perceived display system for human VR and/or AR. 4A-4D illustrate various systems, subsystems, and components to address the goal of providing a high quality, pleasingly perceived display system for human VR and/or AR. 4A-4D illustrate various systems, subsystems, and components to address the goal of providing a high quality, pleasingly perceived display system for human VR and/or AR. FIG. 5 illustrates a plan view of an exemplary configuration of a system utilizing improved diffractive structures. FIG. 6 illustrates a stacked waveguide assembly. FIG. 7 illustrates the DOE. Figures 8 and 9 illustrate exemplary diffraction patterns. Figures 8 and 9 illustrate exemplary diffraction patterns. Figures 10 and 11 illustrate two waveguides into which the beam is injected. Figures 10 and 11 illustrate two waveguides into which the beam is injected. FIG. 12 illustrates a stack of waveguides. FIG. 13A illustrates an exemplary approach for implementing a diffractive structure having a waveguide substrate and upper grating surface, but no underlying layer. FIG. 13B shows a chart of exemplary simulation results. FIG. 13C shows an annotated version of FIG. 13A. FIG. 14A illustrates an exemplary approach for implementing a diffractive structure having a waveguide substrate, bottom layer, and top grating surface. FIG. 14B illustrates an exemplary approach for implementing a diffractive structure having a waveguide substrate, bottom layer, grating surface, and top surface. FIG. 14C illustrates an exemplary approach for implementing a stack of diffractive structures having a waveguide substrate, bottom layer, grating surface, and top surface. FIG. 15A illustrates an exemplary approach for implementing a diffractive structure having a high index waveguide substrate, a low index underlayer, and a low index top grating surface. FIG. 15B shows a chart of exemplary simulation results. FIG. 16A illustrates an exemplary approach for implementing a diffractive structure having a low index waveguide substrate, a high index lower layer, and a low index upper grating surface. FIG. 16B shows a chart of exemplary simulation results. FIG. 17A illustrates an exemplary approach for implementing a diffractive structure having a low index waveguide substrate, a medium index underlayer, and a high index top grating surface. FIG. 17B shows a chart of exemplary simulation results. Figures 18A-D illustrate modification of underlayer properties. Figures 18A-D illustrate modification of underlayer properties. Figures 18A-D illustrate modification of underlayer properties. Figures 18A-D illustrate modification of underlayer properties. FIG. 19 illustrates an approach for implementing precise variable volume deposition of transfer material onto a single substrate. FIG. 20 illustrates an approach and transfer steps for implementing directional co-deposition of multiple different transfer materials into the same layer, according to some embodiments. 21A-B illustrate exemplary approaches for implementing two-sided transfer in the context of a total internal reflection diffractive optical element. FIG. 22 illustrates a structure formed using the approach shown in FIGS. 21A-B. FIG. 23 illustrates an approach for implementing multi-layer overtransfer. FIG. 24 illustrates an approach for implementing multi-layer isolation/offset substrate integration. FIG. 25 illustrates an approach for implementing variable volume deposition of material distributed across a substrate to address surface non-uniformities.

According to some embodiments of the present invention, a diffractive structure is employed, the diffractive structure comprising an underlayer/middle layer between the waveguide substrate and the upper grating surface. The upper grating surface comprises a first material corresponding to a first refractive index value, the lower layer comprises a second material corresponding to a second refractive index value, and the substrate comprises a third refractive index value. A corresponding third material is provided.

One advantage of this approach is that with proper selection of the relative indices of refraction for the three layers, the minimum total internal reflection angle is reduced as the index of refraction is increased, resulting in the structure being able to accommodate a wider range of incidence. It is possible to get a wider field of view for the light. Diffraction efficiency can be increased, allowing for “brighter” light output to the display of the image viewing device.

Various combinations are available, where a lower layer of one index of refraction is combined with an upper grating of another index, along with a substrate of a third index of refraction; provides many variations in the dependence of diffraction efficiency on . A layered waveguide with layers of different refractive indices is presented. Various combinations and permutations are presented along with associated performance data to demonstrate functionality. Advantages include an increase in angle, which provides an increase in output angle with the grating and thus an increase in field of view with the eyepiece. Additionally, the ability to counter the normal decrease in diffraction efficiency with angle is functionally beneficial.

(Display system according to some embodiments)
This portion of the disclosure describes exemplary display systems that may be used in conjunction with the improved diffractive structures of the present invention.

FIG. 2 illustrates a conventional stereoscopic 3D simulation display system, typically having separate displays 74 and 76 for each eye 4 and 6, respectively, at a fixed radial focal distance 10 from the eye. This conventional approach fails to take into account many of the useful cues utilized by the human eye and brain for detecting and interpreting depth in three dimensions, including accommodation cues.

In fact, the typical human eye is capable of interpreting a large number of depth layers, for example about 12 depth layers, based on radial distance. A near field limit of about 0.25 meters is approximately the closest depth of focus, and a far field limit of about 3 meters means that any item more than about 3 meters away from the human eye receives infinity focus. do. The focal layer becomes thinner and thinner closer to the eye. In other words, the eye can perceive focal length differences that are very small relatively close to the eye, and this effect dissipates as objects are further away from the eye. At infinite object locations, the depth of focus/refraction interval value is approximately 1/3 diopters.

FIG. 3 illustrates an improved approach for implementing a stereoscopic 3D simulation display system, according to some embodiments of the present invention, with two composite images, one for each eye 4 and 6. different radial depths of focus (12) for different sides (14) of each image are utilized to provide the perception of three-dimensional depth stratification within the image perceived by each eye. obtain. Since multiple focal planes (e.g., 12 focal planes) exist between the user's eye and infinity, these focal planes and the data in the depicted relationship help define the virtual elements for the user's viewing. It can be used to locate within an augmented reality scenario. This is because the human eye is constantly moving and utilizes the focal plane to perceive depth. Although this diagram shows a particular number of focal planes at various depths, implementations of the invention may use any number of focal planes as needed for the particular application desired, and the invention is therefore not limited to devices having only the specific number of focal planes shown in any of the figures in this disclosure.

4A-4D, some general component options are illustrated according to some embodiments of the present invention. In the portion of the detailed description that follows the discussion of FIGS. 4A-4D, various systems, subsystems, and components provide a high quality, pleasingly perceived display system for human VR and/or AR. Presented to address the purpose.

As shown in Figure 4A, an AR system user (60) is depicted wearing a frame (64) structure coupled to a display system (62) positioned in front of the user's eyes. A speaker (66), in the depicted configuration, is coupled to frame (64) and positioned adjacent to the user's ear canal (in one embodiment, another speaker, not shown, is adjacent to the user's other ear canal). and provides stereo/shapable sound control). The display (62) is operably coupled (68), such as by a wired lead or wireless connection, to a local processing and data module (70), the data module (70) being fixedly attached to the frame (64). , fixedly attached to a helmet or hat (80), as shown in the embodiment of FIG. 4B, embedded within headphones, and in a rucksack configuration to the user (as shown in the embodiment of FIG. 4C). 60), or removably attached to the waist (84) of the user (60) in a belt-tie configuration, as shown in the embodiment of FIG. 4D, It can be mounted in various configurations.

The local processing and data module (70) may comprise a power saving processor or controller and digital memory such as flash memory, both of which may be utilized to assist in data processing, caching and storage. Data is a) from sensors that may be operably coupled to the frame (64) such as image capture devices (such as cameras), microphones, inertial measurement units, accelerometers, compasses, GPS units, wireless devices, and/or gyroscopes. captured data; and/or b) retrieved and/or processed using a remote processing module (72) and/or a remote data repository (74), possibly for processing or retrieval before passing to a display (62) This is the data that has been The local processing and data module (70) may be operably coupled, such as via a wired or wireless communication link, to a remote processing module (72) and a remote data repository (74) (76, 78), these remote modules ( 72, 74) are operatively coupled to each other and available as resources to local processing and data modules (70).

In one embodiment, remote processing module (72) may comprise one or more relatively powerful processors or controllers configured to analyze and process data and/or image information. In one embodiment, remote data repository (74) may comprise a relatively large scale digital data storage facility that may be available through the Internet or other networking configuration in a "cloud" resource configuration. In one embodiment, all data is stored and all calculations are performed in the local processing and data module, allowing full autonomous use from any remote module.

Perception of Z-axis difference (ie, linear distance from the eye along the optical axis) can be facilitated by waveguides with variable focus optic configurations. Image information from the display can be collimated, injected into a waveguide and distributed in a large exit pupil fashion using any suitable substrate-guided optical method known to those skilled in the art, and then variable focus Optical element capabilities can be utilized to change the focus of the wavefront of the light emerging from the waveguide, providing the eye with the perception that the light emerging from the waveguide is from a particular focal length. In other words, the incident light is collimated to avoid problems in a total internal reflection waveguide configuration, so that it exits in a collimated manner, allowing the viewer's eye to accommodate to the far point, Requires it to be focused on the retina, necessarily as it would be from optical infinity, unless some other intervention causes the light to be refocused and perceived as from a different viewing distance. will be interpreted. One such intervention that is suitable is a variable focus lens.

In some embodiments, collimated image information is launched into a piece of glass or other material at an angle such that it is totally internally reflected and passed into an adjacent waveguide. The waveguide may be configured such that collimated light from the display is distributed to exit substantially uniformly across the distribution of reflectors or diffractive features along the length of the waveguide. Upon exiting toward the eye, the exiting light is passed through the variable focus lens element and, depending on the controlled focus of the variable focus lens element, exits the variable focus lens element and enters the eye with varying levels of light. (a collimated flat wavefront represents optical infinity; larger beam divergence/wavefront curvature represents a closer viewing distance to the eye 58).

In a "frame sequential" configuration, stacks of sequential two-dimensional images are sequentially fed to a display in a manner similar to the way a computed tomography system uses stacked image slices to represent three-dimensional structures, resulting in three-dimensional Perceptions can be generated over time. A series of 2D image slices can be presented to the eye, each at a different focal length to the eye, and the eye/brain will integrate such stacks into the perception of a coherent 3D volume. Depending on the display type, row-by-row or even pixel-by-pixel ordering can be done to create the perception of three-dimensional viewing. For example, in a scanning light display (such as a scanning fiber display or a scanning mirror display), the display presents the waveguide one line or one pixel at a time in a sequential manner.

Referring to FIG. 6, a stacked waveguide assembly (178) has multiple waveguides (182, 184, 186, 188, 190) and multiple weak lenses (198, 196, 194, 192). can be utilized to provide three-dimensional perception to the eye/brain by using multiple waveguides and multiple weak lenses, each waveguide indicating the focal length to be perceived for that waveguide level. Together they are configured to transmit image information to the eye at various levels of wavefront curvature for the tube level. Multiple displays (200, 202, 204, 206, 208), or in another embodiment a single multiplexed display, are collimated into waveguides (182, 184, 186, 188, 190) can be utilized to inject image information, each of the waveguides being configured to distribute incident light substantially equally over the length of each waveguide for emission to the eye, as described above; can be

The waveguides (182) closest to the eye are configured to deliver collimated light to the eye, which may represent an optical infinity focal plane, as it is launched into such waveguide (182). be. The next upper waveguide (184) is to transmit collimated light that passes through a first weak lens (192; e.g., weak negative lens) before it can reach the eye (58). Configured. Such a first weak lens (192) allows the eye/brain to direct light emanating from its next upper waveguide (184) from a first focal plane closer inward toward the person from optical infinity. can be configured to create some convex wavefront curvature, as interpreted as Similarly, the third upper waveguide (186) passes its output light through first (192) and second (194) lenses before reaching the eye (58). The combined power of the first (192) and second (194) lenses allows the eye/brain to direct light originating from the third waveguide (186) above it to the next upper waveguide ( 184) to create another increasing amount of wavefront divergence to interpret the light from optical infinity as originating from a second focal plane even closer inward toward the person. .

The other waveguide layers (188, 190) and weak lenses (196, 198) are similarly configured, with the highest waveguide (190) in the stack representing the focal plane closest to the person, of total focal power. To do so, it transmits its output through all of the weak lenses between it and the eye. Compensating lens layer to compensate for the stacking of lenses (198, 196, 194, 192) when viewing/interpreting light originating from the world (144) on the other side of the stacked waveguide assembly (178) (180) is placed at the top of the stack to compensate for the total power of the lens stack below (198, 196, 194, 192). Such a configuration provides as many perceived focal planes as there are waveguide/lens pairs available, again with a relatively large exit pupil configuration, as described above. Both the reflective side of the waveguide and the focusing side of the lens can be static (ie, not dynamic or electroactive). In an alternative embodiment, which is dynamic and uses electro-active features as described above, a small number of waveguides can be multiplexed in a time-sequential manner to produce a larger number of effective focal planes. obtain.

Various diffractive configurations can be employed to focus and/or redirect the collimated beam. For example, passing a collimated beam through a linear diffraction pattern such as a Bragg grating will deflect or "steer" the beam. Passing a collimated beam through a radially symmetric diffraction pattern, or "Fresnel zone plate" will change the focus of the beam. A combined diffraction pattern with both linear and radial elements can be employed to produce both deflection and focusing of a collimated input beam. These deflection and focusing effects can be produced in reflective as well as transmissive modes.

These principles can be applied in conjunction with waveguide configurations to allow additional optics control. As shown in Figure 7, the diffraction pattern (220), or "diffractive optical element" (or "DOE"), changes as the collimated beam undergoes total internal reflection along the planar waveguide (216). , is embedded in the planar waveguide (216) such that it intersects the diffraction pattern (220) at multiple locations. The structure may also include another waveguide (218) into which a beam may be injected (e.g., by a projector or display), and the DOE (221) within this another waveguide (218). Embedded.

Preferably, the DOE (220) deflects only a portion of the light of the beam toward the eye (58) with each crossing point of the DOE (220), while the remainder is via total internal reflection. It has a relatively low diffraction efficiency as it continues to travel through the planar waveguide (216). The light carrying the image information is thus split into a number of related light beams that exit the waveguide at multiple locations, the result being a planar waveguide (216), as shown in FIG. A very uniform pattern of outgoing emissions towards the eye (58) for this particular collimated beam bouncing off at . The exit beams towards the eye (58) are shown in FIG. 8 as substantially parallel since in this case the DOE (220) has only a linear diffraction pattern. However, changes to this linear diffraction pattern pitch can be exploited to controllably deflect the outgoing collimated beam, thereby creating scanning or tiling functionality.

Referring to FIG. 9, as the radially symmetric diffraction pattern components of the embedded DOE (220) change, the exit beam pattern becomes more divergent, which causes the eye to accommodate for closer distances, We want the exit beam pattern to be focused on the retina, which will be interpreted by the brain as light from a viewing distance closer to the eye than optical infinity.

Referring to FIG. 10, along with the addition of other waveguides (218) into which beams can be injected (eg, by a projector or display), other waveguides (218) such as linear diffraction patterns The DOE (221) embedded within may serve to spread the light across a larger planar waveguide (216), which may vary depending on the particular DOE configuration in operation. 216) to provide a very large incident field of incident light, e.g. a large eyebox, to the eye (58).

Although the DOEs (220, 221) are depicted as bisecting the associated waveguides (216, 218), this need not be the case. They can also be placed closer to or on either side of either of the waveguides (216, 218) so as to have the same functionality. Thus, as shown in FIG. 11, with the injection of a single collimated beam, the entire field of cloned collimated beams can be directed toward the eye (58). In addition, for combined linear diffraction pattern/radially symmetric diffraction pattern scenarios such as those described above, beam distribution waveguide optics with Z-axis focusing capability (for functionality such as functional extension of the exit pupil , in those configurations of FIG. 11, the exit pupil can be as large as the optical element itself, which can be a very significant advantage for user comfort and ergonomics), but the presentation , and both the divergence angle of the cloned beams and the wavefront curvature of each beam represent light originating from points closer than optical infinity.

In one embodiment, one or more DOEs are switchable between an actively diffracting "on" state and a non-significantly diffracting "off" state. For example, the switchable DOE may comprise a layer of polymer-dispersed liquid crystal, in which the microdroplets comprise the diffraction pattern in the host medium, and the refractive index of the microdroplets It can be switched to substantially match the refractive index of the material (in which case the pattern does not significantly diffract the incident light), or the microdroplets can be switched to a refractive index that does not match that of the host medium. It can be switched (in which case the pattern actively diffracts incident light). Additionally, beam scanning or tiling functionality can be achieved with dynamic changes to the diffraction term. As previously mentioned, it is desirable to have relatively low diffraction grating efficiencies in each of the DOEs (220, 221). Because it facilitates the distribution of light, and furthermore, light coming through the waveguide that is desirably transmitted (e.g. light originating from the world 144 towards the eye 58 in an augmented reality configuration) This is because the lower diffraction efficiency of the DOE (220) that it intersects is less affected and thus a better view of the real world is achieved through such a configuration.

Arrangements such as those illustrated herein are preferably driven with image information injection in a time-sequential approach, with frame-sequential driving being the simplest to implement. For example, an image of the sky at optical infinity can be thrown in at time 1 and a diffraction grating that keeps the light collimated can be used. An image of a closer tree branch can then be thrown in at time 2 while the DOE controllably imparts focus changes, e.g. Provides the perception of coming from a closer focal length. This kind of paradigm can be repeated in a fast time series fashion such that the eye/brain perceives the input to be all parts of the same image. This is just an example of two focal planes. Preferably, the system will include more focal planes to provide smoother transitions between objects and their focal lengths. This type of configuration generally assumes that the DOE is switched relatively slowly (ie, in the range of tens to hundreds of cycles/second, synchronous with the frame rate of the display that populates the image).

On the contrary, the DOE element can shift the focus by tens to hundreds of MHz or more as the pixels are scanned into the eye (58) using a scanning light display type approach. , a configuration that facilitates switching the focus state of the DOE elements on a pixel-by-pixel basis. This means that the overall display frame rate can be kept very low (low enough to ensure that "flicker" is not a problem (in the range of about 60-120 frames/sec)). Desirable, because it means.

Between these ranges, if the DOE can be switched at a KHz rate, the focus on each scan line can be adjusted on a row-by-row basis, which gives the user an indication of, for example, temporal artifacts during eye movement relative to the display. From a point of view, it can give tangible advantages. For example, different focal planes in a scene may be interleaved in this manner to minimize visible artifacts in response to head movement (as discussed in detail later in this disclosure). A row-by-row focus modulator can be operatively coupled to a line-scan display, such as a grating light valve display, in which a linear array of pixels is swept to form an image. The row-by-row focus modulator can be operably coupled to scanned light displays such as fiber scanned displays and mirror scanned light displays.

A stacked configuration similar to that of FIG. 6 can use dynamic DOEs to provide multi-plane focusing simultaneously. For example, with three simultaneous focal planes, the principal focal planes (eg, based on measured ocular accommodation) can be presented to the user, with +margin and −margin (i.e., one closer focal plane, One more distant focal plane) can be utilized to provide a large focal range that the user can accommodate before a plane update is required. This increased focus range can provide a temporal advantage when the user switches to a closer or farther focus (i.e., as determined by accommodation measurements), with the new plane of focus centered on , and the + and - margins are again ready for fast switching to either side while the system catches up.

Referring to FIG. 12, collimated images having reflectors (254, 256, 258, 260, 262) at one end and cast at one end by displays (224, 226, 228, 230, 232), respectively A planar waveguide (244, 246, A stack (222) of 248, 250, 252) is shown. Each of the reflectors may all have slightly different angles to reflect the emitted light toward a common destination, such as the pupil. Lenses (234, 236, 238, 240, 242) may be inserted between the display and the waveguide for beam steering and/or focusing.

As mentioned above, objects at optical infinity produce substantially plane wavefronts, while objects closer, such as 1 m from the eye, produce curved wavefronts (with about 1 m convex radii of curvature). The optics of the eye have sufficient refractive power to bend an incident ray of light so that it is ultimately focused on the retina (convex wavefront is changed to concave and then to focus on the retina) must have These are the basic functions of the eye.

In many of the above embodiments, the light directed at the eye is treated as part of one continuous wavefront, some of which will impinge on the pupil of a particular eye. In another approach, the light directed to the eye can be effectively discretized or split into multiple beamlets or individual rays, each of which can be functionally created by a set of beamlets or rays. As part of a larger aggregate wavefront, it has a diameter and unique propagation path of less than about 0.5 mm. For example, curved wavefronts are approximated by gathering a plurality of separate, neighboring collimated beams approaching the eye from the appropriate angle to represent the origin, each coinciding with the center of the radius of curvature of the desired aggregated wavefront. obtain.

When the beamlets have a diameter of about 0.5 mm or less, it is as if they were generated through a pinhole lens configuration, which means that each individual beamlet is always independent of the accommodation state of the eye. , at relative focal points on the retina, however the trajectory of each beamlet will be affected by the accommodation state. For example, if the beamlets approach the eye parallel and represent a discretized, collimated collective wavefront, then an eye that is correctly accommodated to infinity will all converge to the same shared spot on the retina. , will deflect the beamlets and appear in focus. If the eye accommodates, say, to 1 m, the beam will be focused to a spot in front of the retina, cross paths, and hit multiple nearby or partially overlapping spots on the retina, appearing blurred.

If the beamlets approach the eye in a diverging configuration and the shared origin is 1 meter from the viewer, 1 m accommodation steers the beams to a single spot on the retina and should appear in focus. deaf. If the viewer adjusts to infinity, the beamlets will converge to a spot behind the retina, creating multiple nearby or partially overlapping spots on the retina, creating a blurred image. Stated more generally, accommodation of the eye determines the degree of overlap of the spots on the retina, and a given pixel is "in focus" when all of the spots are directed to the same spot on the retina. "cage" and "defocused" when the spots are offset from each other. This notion that beamlets of diameter 0.5 mm or less can all be focused at all times and aggregated to be perceived by the eye/brain as being substantially identical to the coherent wavefront is It can be utilized in creating compositions for comfortable 3D virtual or augmented reality perception.

In other words, a set of multiple narrow beams can be used to mimic the situation with a larger diameter varifocal beam, and if the beamlet diameter is kept at a maximum of about 0.5 mm, if desired, the comparison In order to maintain a static focus level and produce a defocused perception, beamlet angular trajectories can be chosen to create an effect similar to a larger defocused beam (such defocus The process may not be identical to Gaussian blurring as for larger beams, but will produce a multimodal point spread function that can be interpreted in a manner similar to Gaussian blurring).

In some embodiments, the beamlets are not mechanically deflected to create this collective focal effect, but rather the eye is sensitive to both multiple angles of incidence and multiple locations at which the beamlets intersect the pupil. receive a superset of many beamlets, including Some of the beamlets from the superset (either emitted from the same shared origin in space or ) are turned on with matching color and intensity to represent the aggregate wavefront, while beamlets in the superset that are inconsistent with the shared origin are not turned on with their color and intensity. (although some of them may be turned on at some other color and intensity level to represent different pixels, for example).

Referring now to FIG. 5, an exemplary embodiment 800 of an AR system using modified diffractive structures will now be described. An AR system generally includes an image generation processor 812, at least one FSD 808 (fiber scanning device), FSD circuitry 810, coupling optics 832, and waveguides stacked together with an improved diffractive structure described below. and at least one optical assembly (DOE assembly 802) having a wave tube. The system may also include eye tracking subsystem 806 . As shown in FIG. 5, the FSD circuit includes an image generation processor 812 with a Maxim chip CPU 818, a temperature sensor 820, a piezoelectric drive/transducer 822, a red laser 826, a blue laser 828, and a green laser 830. , a circuit 810 in communication with a fiber combiner that combines all three lasers 826 , 828 , 830 . Note that other types of imaging techniques can also be used instead of FSD devices. For example, high resolution liquid crystal display (“LCD”) systems, backlit ferroelectric panel displays, and/or high frequency DLP systems may all be used in some embodiments of the invention.

The image generation processor is responsible for generating the virtual content that is ultimately displayed to the user. An image generation processor may convert an image or video associated with the virtual content into a format that can be projected to the user in 3D. For example, in generating 3D content, virtual content needs to be formatted such that portions of a particular image are displayed on particular depth planes, while others are displayed on other depth planes. can be. Alternatively, the images may all be generated at a particular depth plane. Alternatively, the image generation processor may be programmed to feed slightly different images to the right and left eyes such that when viewed together, the virtual content appears coherent and comfortable to the user's eyes. In one or more embodiments, the image generation processor 812 delivers virtual content to the optical assembly in a chronological fashion. A first portion of the virtual scene may be delivered first such that the optical assembly projects the first portion at a first depth plane. Image generation processor 812 may then deliver another portion of the same virtual scene such that the optical assembly projects the second portion into a second depth plane, and so on. Here, the Alvarez lens assembly can be laterally translated quickly enough to produce multiple lateral translations (corresponding to multiple depth planes) on a frame-by-frame basis.

Image generation processor 812 may further include memory 814, CPU 818, GPU 816, and other circuitry for image generation and processing. The image generation processor can be programmed with desired virtual content to be presented to the user of the AR system. It should be appreciated that in some embodiments, the image generation processor may be housed within the wearable AR system. In other embodiments, the image generation processor and other circuitry may be housed within a beltpack coupled to the wearable optics.

The AR system also includes coupling optics 832 for directing light from the FSD to optical assembly 802 . Coupling optics 832 may refer to one or more conventional lenses used to direct light into the DOE assembly. The AR system also includes an eye tracking subsystem 806 configured to track the user's eyes and determine the user's focus.

In one or more embodiments, software blur can be used to induce blur as part of the virtual scene. A blur module may be part of the processing circuitry in one or more embodiments. A blur module may blur a portion of one or more frames of image data being fed into the DOE. In such embodiments, the blur module may completely blur portions of frames that are not intended to be rendered at a particular depth frame. An exemplary approach that may be used to implement the aforementioned image display system and components therein is described in US patent application Ser. No. 14/555,585.

(improved diffraction structure)
As previously described, a collimated beam is totally internally reflected along the planar waveguide, and a diffraction pattern is formed on the planar waveguide such that the beam intersects the diffraction pattern at multiple locations. be able to. This array can be stacked to provide image objects at multiple focal planes within a stereoscopic 3D simulation display system, according to some embodiments of the present invention.

FIG. 13A illustrates one possibility that may be taken to implement the structure 1300 of a waveguide 1302 (also referred to herein as a “light guide,” “substrate,” or “waveguide substrate”). approach, in which an outcoupling grating 1304 is formed directly on the top surface of waveguide 1302, e.g., as a combined monolithic structure, and/or both are formed from the same material ( (even if not built from the same monolithic structure). In this approach, the refractive index of the grating material is the same as that of waveguide 1302 . The refractive index n (or “refractive index”) of a material describes the degree to which light propagates through its medium and is defined as n=c/v, where c is the speed of light in a vacuum and v is is the phase velocity of light in the medium. The index of refraction determines the degree to which light is bent or refracted as it enters the material.

FIG. 13B shows a chart 1320 of exemplary simulation results for a single polarization of the efficiency of light exiting structure 1300 as a function of the angle at which light is propagating in the waveguide. The chart shows that the diffraction efficiency of light outcoupled to structure 1300 decreases at higher angles of incidence. As can be seen, at an angle of about 43 degrees, the efficiency drops relatively steeply on the plots depicted due to the total internal reflectance variation with angle of incidence in media with uniform refractive index.

Thus, the usable range of configuration 1300 is somewhat limited, and thus undesirable as the bounce spacing may decrease at higher angles of incidence, which may also reduce the brightness seen by the observer at those angles. Is possible. Diffraction efficiency is lower at the shallowest angles of incidence, which is quite desirable as the bounce spacing between interactions with the top surface (see FIG. 13C) is very far and the chances of light outcoupling are very low. do not have. Dimming signals with fewer outcoupled samples will therefore result from this arrangement, a problem exacerbated by gratings with lower diffraction efficiencies at these high angles with this polarization orientation. Will. Note that "1T" as used herein and in the figures refers to the first transmission diffraction order.

In some embodiments of waveguide-based optical systems or substrate-guided optical systems such as those described above, different pixels in the substrate-guided image are represented by beams propagating at different angles in the waveguide, and the light is , propagate along the waveguide by total internal reflection (TIR). The range of beam angles that remain trapped within the waveguide by TIR is a function of the refractive index difference between the waveguide and the medium outside the waveguide (eg, air). The higher the refractive index difference, the greater the number of beam angles. In some embodiments, the range of beam angles propagating along the waveguide is correlated with the field of view of the image coupled out of the plane of the waveguide by the diffractive element and with the image resolution supported by the optical system. Correlate. Additionally, the angular range over which total internal reflection occurs is dictated by the refractive index of the waveguide. In some embodiments, a minimum of about 43 degrees and a practical maximum of about 83 degrees, thus a range of 40 degrees.

FIG. 14A illustrates an approach for addressing this problem, according to some embodiments of the present invention, in which a structure 1400 includes an intermediate layer 1406 (herein , referred to as “lower layer 1406”). Top surface 1304 comprises a first material corresponding to a first refractive index value, bottom layer 1406 comprises a second material corresponding to a second refractive index value, and substrate 1302 comprises a third refractive index value. It has a third material corresponding to the value. Any combination of the same or different materials may be employed to implement each of these portions of structure 1400, for example all three materials are different (and all three materials correspond to different refractive index values). ), or two of the layers share the same material (e.g., two of the three materials are the same and thus have a common refractive index that differs from the refractive index value of the third material). share values). Any combination of refractive index values can be employed. For example, one embodiment includes a low refractive index for the underlayer and uses higher refractive index values for the surface grating and substrate. Other exemplary configurations having other exemplary combinations of refractive index values are described below. Any suitable set of materials may be used to implement structure 1500 . For example, polymers, glass, and sapphire are all examples of materials that may be selected to implement any of the layers of structure 1400 .

As shown in FIG. 15A, in some embodiments, a relatively higher index substrate is used as the waveguide substrate 1302, with a relatively lower index underlayer 1406 and a relatively lower index upper grating surface. It may be desirable to implement structure 1500 with 1304 . It is possible to obtain a wider field of view through the relationship n1*sin(θ1)=n2*sin(90) and from the fact that the minimum total internal reflection angle is reduced as the refractive index is increased. Because you get For a substrate with a refractive index of 1.5, the critical angle is 41.8 degrees. However, for a substrate refractive index of 1.7, the critical angle is 36 degrees.

A grating formed on a higher refractive index substrate will outcouple light even if it itself has a lower refractive index, as long as the layer of material that makes up the grating is not too thick between the grating and the substrate. can be used to This is related to the fact that such a configuration can be used to have a wider range of angles for total internal reflection (“TIR”). In other words, the TIR angle drops to lower values with such a configuration. Additionally, it should be noted that many of the current etching processes may not be well suited for extending to high index glasses. In some embodiments, it is desirable to reliably and inexpensively replicate the outer bonding layer.

The composition of underlayer 1406 can be adjusted to alter the performance characteristics of structure 1500 by, for example, changing the thickness of underlayer 1406 . The configuration of FIG. 15A (the structure includes a grating structure 1304 on top comprising a relatively low refractive index material, with an associated lower refractive index underlayer 1406, which has an associated high refractive index light guiding substrate). 1302) can be modeled to yield data such as that depicted in FIG. 15B. Referring to this figure, the left plot 1502a relates to a configuration with a zero thickness underlayer 1502. FIG. Center plot 1502b shows data for underlayer 1502 that is 0.05 microns thick. The right plot 1502c shows data for a 0.1 micron thick underlayer 1502 .

As shown by the data in these plots, as the underlayer thickness is increased, the diffraction efficiency as a function of angle of incidence becomes much more nonlinear and suppressed at high angles, which may be undesirable. Therefore, in this case, the underlying control is the key functional input. However, when using only a zero-thickness underlayer and the grating feature itself possessing a lower index of refraction, the range of angles supported by the structure is limited to the higher index base material, not the lower index grating feature material. Note that it is governed by TIR conditions.

Referring to FIG. 16A, an embodiment of a structure 1600 featuring a relatively high refractive index underlayer 1406 on a lower refractive index substrate 1302 is illustrated, the top surface grating 1304 being lower than the underlayer 1406, not necessarily It has an index of refraction comparable to, but not equal to, that of the substrate 1302 . For example, the top surface grating may correspond to a refractive index of 1.5, the lower layer may correspond to a refractive index of 1.84, and the substrate may correspond to a refractive index of 1.5. For this example, assume that the period is 0.43 μm and λ corresponds to 0.532 μm.

A simulation related to such a configuration is presented in FIG. 16B. As shown in this figure, for chart 1602a with a 0.3 micron thick underlayer 1406, the diffraction efficiency drops as in the previous configuration, but then begins to rise at the higher end of the angular range. This is also true for the 0.5 micron thick underlayer 1406 configuration, as shown in chart 1602b. Advantageously, in each of these (0.3 micron, 0.5 micron) configurations, the efficiency is relatively high at the higher extremes of the angular range. Such functionality may tend to counteract the more sparse bounce spacing concerns discussed above. Also shown in this figure is a chart 1602c for an embodiment featuring an example of 90 degree rotated polarization, where the diffraction efficiency is low as might be expected, but is steeper compared to shallower angles. It exhibits desirable behavior in terms of providing greater efficiency at angles.

In fact, in some embodiments, diffraction efficiency versus angle may increase at higher angles. This may be a desirable feature for some embodiments as it helps compensate for the lower bounce spacing that may occur at higher propagation angles. Thus, the structural configuration of FIG. 16A promotes an increase in diffraction efficiency vs. angle at higher angles and may therefore be preferred in embodiments where it is desirable to compensate for lower bounce spacings (occurring with higher propagation angles), It is desirable for the monolithic construction mentioned above.

Referring to FIG. 17A, another structure 1700 is depicted in which underlayer 1406 has a refractive index substantially higher than that of substrate 1302 . The grating structure 1304 is on top, and the grating structure 1304 also has a higher refractive index than the underlying layer 1406 . For example, the top surface grating may correspond to a refractive index of 1.86, the lower layer may correspond to a refractive index of 1.79, and the substrate may correspond to a refractive index of 1.5. As before, assume for this example that the period is 0.43 μm and λ corresponds to 0.532 μm.

Referring to FIG. 17B, chart 1702 shows simulation data illustrated for structure 1700 of FIG. 17A. As shown in chart 1702, the resulting plot of diffraction efficiency versus angle of incidence compensates for the aforementioned lower bounce spacing at relatively high angles of incidence and generally retains reasonable diffraction efficiency over a wider range of angles. demonstrate desirable general behavior that helps to

Note that underlayer 1406 need not be uniform across the substrate. Any property of underlayer 1406 may be varied at different locations on the substrate, such as differences in thickness, composition, and/or refractive index of underlayer 1406 . One possible reason for varying the properties of the underlayer 1406 is to promote uniform display properties in the presence of known variations in either the display image and/or non-uniform transmission of light within the display system. be.

For example, consider the case where a waveguide structure receives incident light at a single internal coupling location 1802 on the waveguide, as shown in FIG. 18A. As incident light is injected into waveguide 1302 , less and less light will remain as it propagates along the length of waveguide 1302 . This means that output light near the incoupling location 1802 may result in appearing “brighter” than output light further along the length of the waveguide 1302 . If the underlayer 1406 is uniform along the length of the waveguide 1302, the optical effect of the underlayer 1406 can enhance this non-uniform brightness level across the substrate.

Properties of the underlayer 1406 can be adjusted across the substrate 1302 to make the output light more uniform. FIG. 18B illustrates an approach in which the thickness of the lower layer 1406 is varied over the length of the waveguide substrate 1302, with the lower layer 1406 being thinner near the internal coupling location 1802 and thicker with increasing distance from the location 1802. Become. Thus, the effect of underlayer 1406 to promote greater diffraction efficiency is, at least in part, to ameliorate the effects of optical loss along the length of waveguide substrate 1302, thereby reducing the overall can promote a more uniform light output over the

FIG. 18C illustrates an alternative approach in which the thickness of underlayer 1406 is not varied, but the refractive index of underlayer 1406 is varied across substrate 1302 . For example, to address the problem that output light near location 1802 tends to be brighter away from location 1802, the refractive index for lower layer 1406 is the same or similar to substrate 1302 near location 1802. , but configured to have an increasing difference in their refractive index values at locations away from location 1802 . The composition of the underlayer 1406 material can be varied at different locations to yield different refractive index values. FIG. 18D illustrates a hybrid approach in which both the thickness and refractive index of underlayer 1406 are varied across substrate 1302 . Note that this same approach can be taken to vary the thickness and/or refractive index of upper grating surface 1304 and/or substrate 1302 in conjunction with or instead of varying lower layer 1406. sea bream.

Thus, various combinations are available, with a lower layer 1406 of one index of refraction combined with a substrate 1302 of a third index of refraction, with an upper grating 1304 of another index of refraction, and adjusting the relative values of these , which provides many variations in the dependence of the diffraction efficiency on the angle of incidence. A layered waveguide with layers of different refractive indices is presented. Various combinations and permutations are presented along with associated performance data to demonstrate functionality. Advantages include increased angle, which provides an increased output angle with the grating 1304 and thus an increased field of view with the eyepiece. Additionally, the ability to counteract the normal decrease in diffraction efficiency with angle is functionally beneficial.

FIG. 14B illustrates an embodiment in which another layer (top surface) of material 1409 is placed above grating layer 1304 . Layer 1409 can be implemented configurable to address different design goals. For example, layer 1409 can form an intervening layer between multiple stacked diffractive structures 1401a and 1401b, eg, as shown in FIG. 14C. As shown in FIG. 14C, this intervening layer 1409 can be employed to eliminate any voids/gaps and provide a support structure for the stacked diffractive components. In this use case, layer 1409 can be formed from a material having a relatively low refractive index, eg, approximately 1.1 or 1.2. Although not shown in this figure, other layers (such as weak lenses) may also be placed between diffractive structures 1401a and 1401b.

Additionally, layer 1409 can be formed from a material having a relatively high refractive index. In this situation, it is the grating on layer 1409 rather than grating surface 1304 that will provide a diffractive effect for all or a significant amount of the incident light.

As will be apparent, different relative combinations of refractive index values can be selected for different layers, including layer 1409, to achieve desired optical effects and results.

Such structures may be manufactured using any suitable manufacturing technique. Certain high refractive index polymers, such as the one known as "MR174", can be directly embossed, printed, or etched to produce the desired patterned structures, but curing shrinkage and the like of such layers are associated. There are issues to be addressed. Thus, in another embodiment, another material may be transferred, embossed, or etched onto the high refractive index polymer layer (ie, such as a layer of MR174) to produce functionally similar results. Current state-of-the-art printing, etching (i.e., which can include resist removal and patterning steps similar to those utilized in conventional semiconductor processes), and embossing techniques allow such printing, embossing, and/or may be utilized and/or combined to perform etching steps. For example, molding techniques similar to those used in DVD production may also be used for certain replication steps. Additionally, certain jetting or deposition techniques utilized in printing and other deposition processes may also be utilized to deposit certain layers with precision.

The following portions of the disclosure will now describe improved approaches for implementing formed patterns on substrates for diffraction, the imprinting of the deposited imprint material is the Done according to some embodiments of the invention. These approaches allow very precise distribution of transfer material and very precise formation of different transfer patterns on any number of substrate surfaces. Note that the following description can be used with and to implement the lattice configuration described above. However, it should be noted that the deposition approach of the present invention can be used with other configurations as well.

According to some embodiments, a patterned distribution of transfer material (eg, patterned inkjet distribution) is performed to implement the deposition of transfer material onto the substrate. This approach, using patterned inkjet distributions, allows very precise volumetric control over the material to be deposited. In addition, this approach can serve to provide a smaller, more uniform base layer beneath the grating surface, and, as mentioned above, the base thickness of the layer has a significant effect on eyepiece/optical device performance. can have a significant impact.

FIG. 19 illustrates an approach for implementing precise variable volume deposition of transfer material onto a single substrate. As shown, a template 1902 is provided having a first set of deeper depth structures 1904 and a second set of shallower (eg, standard) depth structures 1906 . When depositing transfer material on transfer receiving side 1908 , a relatively larger volume of transfer material 1910 is deposited corresponding to portions of template 1902 with deeper depth features 1904 . In contrast, a relatively smaller volume of transfer material 1912 is deposited corresponding to shallower depth features 1906 of template 1902 . The template is then used to transfer the first and second sets of depth structures into the transfer material to form respective structures having different depths and/or patterns in the transfer material. This approach thus allows simultaneous formation of different features on the transfer recipient 1908 .

This approach can be utilized to generate intentionally non-uniform distributions for structures with different depths and/or feature parameters, e.g., feature structures are on the same substrate and different have a thickness; This can be used, for example, to generate spatially distributed volumes of transfer material that allow simultaneous transfer of structures of variable depth with the same underlayer thickness.

The bottom of FIG. 19 illustrates a structure 1920 formed using the previously described deposition techniques/apparatus, where the underlayer 1922 has a uniform thickness despite differences in pattern depth and volume. It can be seen that the transfer material is deposited in structure 1920 with a non-uniform thickness. Here, top layer 1924 includes a first portion 1926 having a first set of layer thicknesses, while a second portion 1928 has a second set of layer thicknesses. In this example, portion 1926 corresponds to a thicker layer compared to the standard/shallower thickness of portion 1928 . However, any combination of thicknesses can be constructed using the concepts of the present invention, with thicknesses that are either/or thicker and/or less than the standard thickness being formed on the underlying layer. Please note.

This ability can be used, for example, to deposit larger volumes of material to act as spacer elements, and to aid in constructing multilayer diffractive optical elements, for example.

Some embodiments relate to approaches for implementing simultaneous deposition of multiple types of transfer materials onto a substrate. This allows materials with optical properties to be deposited simultaneously over multiple portions of the substrate at one time. This approach is also useful for tuning local areas associated with specific functions (e.g., serving as incoupling gratings, orthogonal pupil expander (OPE) gratings, or exit pupil expander (EPE) gratings)). provide the ability.

FIG. 20 illustrates an approach and transfer steps for implementing directional co-deposition of multiple different transfer materials into the same layer, according to some embodiments. As shown, a template 2002 is provided for transferring patterns into different types of transfer materials 2010 and 2012 on a transfer receiving side 2008 . Materials 2010 and 2012 may comprise the same material with different optical properties (eg, two versions of the same material with different refractive indices) or two entirely different materials.

Any optical property of the material can be considered and selected when employing this technique. For example, as shown in the embodiment of FIG. 20, material 2010 corresponds to a high refractive index material deposited in one section of transfer receiving side 2008, while at the same time material 2012 corresponds to an area of a second section. corresponds to the lower refractive index material deposited within.

As shown in the resulting structure 2020, this forms a multifunctional diffractive optical element having a high refractive index portion 2026 and a lower refractive index portion 2028. FIG. In this case, the high refractive index portion 2026 for the first feature and the portion 2028 for the second feature were transferred simultaneously.

Although this example illustratively identifies the refractive index of a material as an optical property that should be "tuned" when simultaneously depositing materials, other optical properties may also be used to determine the type of material to deposit in different portions of the structure. Note that it may be considered when identifying For example, opacity and absorbance are other properties that can be used to distinguish materials for deposition into different parts of the structure and to adjust the local properties of the final product.

Additionally, one type of material may be deposited above/below another material prior to transfer. For example, one refractive index material can be deposited directly under a second refractive index material just prior to transfer to create a refractive index gradient to form a diffractive optical element. This can be used, for example, to implement the structure shown in FIG. 17A (or any of the other related structures described above or in the figures).

According to another embodiment, multi-sided transfer can be employed to transfer to multiple sides of the optical structure. This allows transfer to occur on different sides of the optical element, implementing multiplexing of functions throughout the base layer volume. In this way different eyepiece functions can be implemented without adversely affecting the grating structure function.

21A-B illustrate exemplary approaches for implementing two-sided transfer in the context of a total internal reflection diffractive optical element. As illustrated in FIG. 21A, a first template 2102a can be used to generate a transfer on side "A" of substrate/transfer receiving side 2108. As shown in FIG. This forms a first pattern 2112 having the first material on side A of the structure.

As illustrated in FIG. 21B, template 2102b can be used to generate a second imprint on side "B" of the same substrate. This forms a second pattern 2114 having a second material on side B of the substrate.

Note that sides A and B can have the same or different patterns and/or can have the same or different types of materials. Additionally, the patterns on each side may comprise varying layer thicknesses (eg, using the approach of FIG. 19) and/or may have different material types on the same side (eg, using the approach of FIG. 20). approach).

As shown in FIG. 22, a first pattern 2112 has been transferred onto side A of substrate 2108 and a second pattern 2114 has been transferred onto opposite side B. FIG. A compound function of the resulting two-sided transferred element 2200 can now be realized. In particular, when incident light is applied to the two-sided transferred element 2200, some light exits the element 2200 and implements the first function 1, while other light exits the second Implement function 2 of 2.

Additional embodiments relate to multi-layer overtransfer and/or multi-layer separation/offset substrate integration. In either/both of these approaches, previously transferred patterns can be jetted and printed again. Adhesive can be jetted onto the first layer, a second substrate is bonded to it (possibly with air gaps), and a subsequent jetting process deposits and transfers onto the second substrate. can be done. A series of transferred patterns can be joined together sequentially in a roll-to-roll process. Note that the approach of implementing multi-layer overtransfer can be used with or instead of the multi-layer separation/offset substrate integration approach.

FIG. 23 illustrates an approach for implementing multi-layer overtransfer. Here, a first transfer material 2301 can be deposited onto a substrate 2308 and transferred. This is followed by deposition (and possible transfer) of a second transfer material 2302 . This results in a composite multilayer structure having both the first transfer material 2301 and the second transfer material 2302 . In one embodiment, a subsequent transfer may be implemented for the second transfer material 2302. In alternative embodiments, subsequent transfer is not implemented for the second transfer material 2302 .

FIG. 24 illustrates an approach for implementing multi-layer isolation/offset substrate integration. Here both the first substrate 1 and the second substrate 2 can be deposited with a transfer material and then transferred. Substrate 1 and Substrate 2 may then be sandwiched and bonded, in one embodiment possibly offset features (also transferred ). Transferred spacers 2404 can be used to create voids 2402 .

According to yet another embodiment, an approach is disclosed for implementing variable volume deposition of material distributed across a substrate, which may rely on a priori knowledge of surface non-uniformities. To illustrate, consider the substrate 2502 shown in FIG. As shown, surface non-uniformities in substrate 2502 can result in undesirable parallelism and poor optical performance. In this case, the substrate 2502 (or previously transferred layer) can be measured for variability.

Variable volume deposition of transfer material can be employed to provide a horizontal distribution of the transfer material to be deposited, independent of the underlying topography or physical feature set. For example, the substrate is pulled flat by a vacuum chuck and in situ measurements can be made to assess surface height using, for example, low coherence or laser-based contact measurement probes. The dispensed volume of transfer material can be varied according to measured data to result in a more uniform layer when reproduced. In this example, substrate portion 2504a has the highest level of variation, portion 2504b has an intermediate level of variation, and portion 2504c has the lowest level of variation. Thus, a large volume of transfer material can be deposited in portion 2504a, a medium volume of transfer material can be deposited in portion 2504b, and a small/standard volume of transfer material can be deposited in portion 2504c. be done. As shown by the resulting product 2506, this results in a more uniform total substrate/transfer material/transfer pattern thickness, which in turn can tune or benefit the performance of the transferred device.

Note that while the example shows variations due to thickness non-uniformity, other types of non-uniformity may also be addressed by this embodiment of the invention. In another embodiment, such variations may result from the presence of pits, peaks, or other anomalies or features associated with localized locations on the substrate.

In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made therein without departing from the broader spirit and scope of the invention. For example, the foregoing process flows have been described with reference to a particular order of process actions. However, the order of many of the process actions described may be changed without affecting the scope or operation of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Various exemplary embodiments of the invention are described herein. Reference is made to these examples in a non-limiting sense. They are provided to illustrate the broader and more explorable aspects of the invention. Various changes may be made to the invention as described and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process act or step to the objective, spirit or scope of the present invention. Moreover, as will be appreciated by those of ordinary skill in the art, each of the individual variations described and illustrated herein may be modified from among several other embodiments without departing from the scope or spirit of the invention. It has discrete components and features that can be easily separated from or combined with any feature. All such modifications are intended to be within the scope of the claims associated with this disclosure.

The present invention includes methods that can be performed using a target device. A method may include an act of providing such a suitable device. Such offerings may be made by end users. In other words, the act of "providing" simply means that the end-user obtains, accesses, approaches, locates, configures, activates, powers on, or claim to act differently. The methods described herein can be performed in any order of the recited events that is logically possible, as well as in the recited order of events.

Illustrative aspects of the invention are described above, along with details regarding material selection and manufacturing. As for other details of the invention, these may be understood in connection with the above-referenced patents and publications and generally known or appreciated by those skilled in the art. The same may hold true with respect to method-based aspects of the invention in terms of additional acts as commonly or logically employed.

Additionally, while the invention has been described with reference to several embodiments that optionally incorporate various features, the invention is described and directed as it is contemplated with respect to each variation of the invention. is not limited to Various changes may be made to the invention as described and equivalents (whether described herein or included for some simplicity) without departing from the true spirit and scope of the invention. or not) can be substituted. Additionally, when a range of values is provided, all intervening values between the upper and lower limits of that range and any other stated or intervening value within the stated range are encompassed within the invention. Please understand.

Any optional feature of the described variations of the invention may be described and claimed independently or in combination with any one or more of the features described herein is also assumed. References to items in the singular include the possibility that there are plural forms of the same item. More specifically, as used herein and in the claims associated herewith, "a", "an", "said", and " The singular form "the (the)" includes plural referents unless otherwise specified. In other words, use of the articles allows for "at least one" of the subject item in the above description as well as the claims associated with this disclosure. It is further noted that such claims may be drafted to exclude any optional element. Accordingly, this statement does not serve as an antecedent for use of exclusive terms such as "only", "only", etc., or use of a "negative" limitation in connection with the recitation of claim elements. intended to fulfill.

The term "comprising" in the claims associated with this disclosure, without the use of such exclusive language, means that a given number of elements are recited or characterized in such claim. It is intended to allow inclusion of any additional elements, regardless of whether the addition of may be viewed as a transformation of the nature of the elements recited in such claims. Unless specifically defined herein, all technical and scientific terms used herein are to be understood in the broadest possible manner while maintaining validity of the claims. It is something that is given a certain meaning.

The scope of the present invention is not limited to the examples and/or subject specification provided, but rather is limited only by the scope of the claim language associated with this disclosure.

The above description of illustrated embodiments is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. Although specific embodiments and examples are described herein for purposes of illustration, various equivalent modifications depart from the spirit and scope of the disclosure, as will be recognized by those skilled in the art. can be done without The teachings provided herein of various embodiments implement a virtual or AR or hybrid system and/or employ a user interface, not necessarily the exemplary AR system generally described above, and/or other device can also be applied.

For example, the foregoing detailed description describes various embodiments of devices and/or processes through the use of block diagrams, schematic diagrams, and examples. To the extent such block diagrams, schematic diagrams, and examples contain one or more functions and/or acts, each function and/or act in such block diagrams, flow diagrams, or examples may: It will be appreciated by those skilled in the art that the implementations can be implemented individually and/or collectively by a wide variety of hardware, software, firmware, or virtually any combination thereof.

In one embodiment, the present subject matter may be implemented via an application specific integrated circuit (ASIC). One skilled in the art, however, will appreciate that the embodiments disclosed herein can be, in whole or in part, as one or more computer programs executed by one or more computers (e.g., on one or more computer systems). as one or more programs executed by one or more controllers (e.g., microcontrollers), one or more programs executed by one or more processors (e.g., microprocessors) The above programs, as firmware, or virtually any combination thereof, can equally be implemented in a standard integrated circuit, designing circuits and/or writing code for software and/or firmware. Incorporation would be well within the skill of one of ordinary skill in the art in light of the teachings of this disclosure.

Once the logic is implemented as software and stored in memory, the logic or information can be stored on any computer-readable medium for use by or in connection with any processor-related system or method. can In the context of this disclosure, memory is a computer-readable medium, be it electronic, magnetic, optical, or other physical device or means, containing or storing a computer and/or processor program. Logic and/or information is a computer-based system, processor-containing system, or other system capable of fetching instructions from an instruction execution system, apparatus, or device, and executing instructions associated with the logic and/or information. It can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, such as a system, apparatus, or device.

In the context of this specification, a "computer-readable medium" stores a program associated logic and/or information for use by or in connection with an instruction execution system, apparatus, and/or device. can be any element. A computer readable medium can be, for example, without limitation, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include portable computer diskettes (magnetic, CompactFlash cards, Secure Digital, or equivalent), random access memory (RAM), read Special purpose memory (ROM), erasable programmable read-only memory (EPROM, EEPROM, or flash memory), portable compact disc read-only memory (CDROM), digital tape, and other non-transitory media would be included.

Many of the methods described herein can be performed with variations. For example, many of the methods may include additional acts, omit some acts, and/or be performed in a different order than that illustrated or described.

The various embodiments described above can be combined to provide further embodiments. All U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to herein and/or listed in application data sheets are herein incorporated by reference for the specific teachings of this specification. and unless contradicted by definitions, which are hereby incorporated by reference in their entirety. Aspects of the embodiments can be modified, if necessary, to employ the systems, circuits, and concepts of the various patents, applications, and publications to provide still further embodiments. .

These and other changes can be made to the embodiments in light of the above detailed description. Generally, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, although such claims should be construed to include all possible embodiments, along with the full range of equivalents to which the Company is entitled. Accordingly, the claims are not limited by the disclosure.

Moreover, the various embodiments described above can be combined to provide additional embodiments. Aspects of the embodiments can be modified, if necessary, to employ concepts of the various patents, applications, and publications to provide yet further embodiments.

These and other changes can be made to the embodiments in light of the above detailed description. Generally, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, although such claims should be construed to include all possible embodiments, along with the full range of equivalents to which the Company is entitled. Accordingly, the claims are not limited by the disclosure.

Claims (15)

A method of manufacturing a diffractive optical element for use in a three-dimensional virtual reality and/or augmented reality display system, said method comprising:
directly depositing a first portion of material and a second portion of material on a substrate, the first portion of material having a first depth and a second portion of material having a first depth; has a second depth, said first depth being different than said second depth;
transferring a patterned template into a set of one or more materials on the substrate, the template comprising a first set of depth structures and a second set of depth structures; , a first portion of the material is deposited at the first depth corresponding to the first set of depth structures, and a second portion of the material corresponds to the second set of depth structures. deposited at said second depth of
including
The method, wherein the transfer pattern comprises a diffraction pattern for the diffractive optical element. The transfer pattern comprises a first pattern and a second pattern,
The method includes forming the first pattern and the second pattern on the substrate by simultaneously transferring the first pattern and the second pattern, the template having the depth transferring said first pattern with a first set of structures onto a first portion of said material, said template transferring said second pattern with said second set of depth structures onto a second portion of said material; 2. The method of claim 1, wherein the transfer onto two parts. 3. The method of claim 2, wherein the first pattern corresponds to a first grating pattern and the second pattern corresponds to a second grating pattern. 4. The method of claim 2 or claim 3, wherein the first portion of material and the second portion of material correspond to a non-uniform distribution of the material over the substrate. A method according to any one of claims 2 to 4, wherein said substrate forms an underlayer of uniform thickness and said first pattern and said second pattern form variable depth structures. A method according to any preceding claim, wherein the first portion of material has different optical properties than the second portion of material. 7. The method of claim 6, wherein different optical properties between the first portion of material and the second portion of material correspond to different refractive indices, different opacities, or different absorbances. 8. A method according to claim 6 or claim 7, wherein the first portion of material is deposited over the second portion of material prior to transfer. depositing a first portion of the material on a first side of the substrate;
depositing a second portion of the material on a second side of the substrate;
transferring the first pattern into a first portion of the material on the first side of the substrate;
transferring the second pattern into a second portion of the material on the second side of the substrate;
The method according to any one of claims 2 to 5, comprising 2. The method of claim 1, wherein the first portion of material is deposited and transferred prior to depositing the second portion of material. 2. The method of claim 1, wherein the method further comprises overlaying a first substrate having a first transfer pattern onto a second substrate having a second pattern. 12. The method of Claim 11, wherein the method further comprises bonding the first substrate having the first transfer pattern to the second substrate having the second pattern. The method includes placing spacers between the first substrate having the first transferred pattern and the second substrate having the second transferred pattern to form the first substrate. 13. The method of claim 11 or 12, further comprising forming an air gap between a substrate and said second substrate. The method further includes depositing variable levels of the set of one or more materials on the substrate, wherein the one material deposited on the substrate.
14. The method of any one of claims 1-13, wherein variability levels of a set of one or more materials are identified by measuring variability in the surface uniformity of the substrate. A method according to any one of the preceding claims, wherein said set of one or more materials is deposited on said substrate by inkjet deposition.

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