Modular Waveguide Displays and Related Applications

The present disclosure relates to modular waveguide displays including: a modular frame; a waveguide lens attached to the modular frame, where the waveguide lens in configured to be attached to the modular frame to locate one or more waveguides within the waveguide lens in front of the modular frame; and an optical engine which is configured to be attached to the modular frame, wherein, when the optical engine is attached to the modular frame, the optical engine is configured to provide image containing information to a front side of the one or more waveguides. Advantageously, a modular waveguide display allows for customization by a user. The modular waveguide display is designed to operate without such components as the optical engine when such functionality is undesired to save weight and power. Also, modular waveguide displays allow for parallel development of components such as the waveguide lens and the optical engine.

FIELD OF THE INVENTION

The present invention generally relates to waveguide-based displays and, more specifically, to modular waveguide displays.

BACKGROUND

Waveguides can be referred to as structures with the capability of confining and guiding waves (i.e., restricting the spatial region in which waves can propagate). One subclass includes optical waveguides, which are structures that can guide electromagnetic waves, typically those in the visible spectrum. Waveguide structures can be designed to control the propagation path of waves using a number of different mechanisms. For example, planar waveguides can be designed to utilize diffraction gratings to diffract and couple incident light into the waveguide structure such that the in-coupled light can proceed to travel within the planar structure via total internal reflection (“TIR”).

Fabrication of waveguides can include the use of material systems that allow for the recording of holographic optical elements within the waveguides. One class of such material includes polymer dispersed liquid crystal (“PDLC”) mixtures, which are mixtures containing photopolymerizable monomers and liquid crystals. A further subclass of such mixtures includes holographic polymer dispersed liquid crystal (“HPDLC”) mixtures. Holographic optical elements, such as volume phase gratings, can be recorded in such a liquid mixture by illuminating the material with two mutually coherent laser beams. During the recording process, the monomers polymerize, and the mixture undergoes a photopolymerization-induced phase separation, creating regions densely populated by liquid crystal micro-droplets, interspersed with regions of clear polymer. The alternating liquid crystal-rich and liquid crystal-depleted regions form the fringe planes of the grating. The resulting grating, which is commonly referred to as a switchable Bragg grating (SBG), has all the properties normally associated with volume or Bragg gratings but with much higher refractive index modulation ranges combined with the ability to electrically tune the grating over a continuous range of diffraction efficiency (the proportion of incident light diffracted into a desired direction). The latter can extend from non-diffracting (cleared) to diffracting with close to 100% efficiency.

Waveguide optics, such as those described above, can be considered for a range of display and sensor applications. In many applications, waveguides containing one or more grating layers encoding multiple optical functions can be realized using various waveguide architectures and material systems, enabling new innovations in near-eye displays for augmented reality (“AR”) and virtual reality (“VR”), compact head-up displays (“HUDs”) and helmet-mounted displays or head-mounted displays (HMDs) for road transport, aviation, and military applications, and sensors for biometric and laser radar (“LIDAR”) applications.

SUMMARY OF THE DISCLOSURE

Many embodiments are directed to modular waveguide display devices, their design, and their methods of use.

Various embodiments are directed to a modular waveguide display device including:a modular frame;a waveguide lens attached to the modular frame, wherein the waveguide lens is configured to be attached to the modular frame to locate one or more waveguides within the waveguide lens in front of the modular frame; andan optical engine which is configured to be attached to the modular frame, wherein, when the optical engine is attached to the frame, the optical engine is configured to provide image containing light to a front side of the one or more waveguides.

In various other embodiments, the front side of the one or more waveguides is the side opposite to a user's eye.

In still various other embodiments, the one or more waveguides include incoupling optical elements and outcoupling optical elements, and where, the optical engine is further configured to inject modulated light into the one or more waveguides through the incoupling optical elements.

In still various other embodiments, the outcoupling optical elements are configured to output the image containing light into a user's eye.

In still various other embodiments, the incoupling optical elements are configured to receive modulated light coming from the same direction as modulated light outputted by the outcoupling optical element.

In still various other embodiments, the modular frame includes at least one of one or more cameras, one or more speakers, one or more microphones, and one or more batteries.

In still various other embodiments, the one or more cameras includes stereo cameras integrated at opposite sides of the modular frame.

In still various other embodiments, the stereo cameras are configured to perform tracking.

In still various other embodiments, the tracking includes six degrees of freedom tracking.

In still various other embodiments, the one or more cameras includes a center camera mounted integrated in the center of the modular frame.

In still various other embodiments, the modular frame is adapted to accept another optical engine which is attachable to and removable from the waveguide lens, wherein, when the other optical engine is attached to the waveguide lens, the other optical engine is configured to inject light containing image information into the one or more waveguides.

In still various other embodiments, the optical engine is configured to be removable from the modular frame and the modular frame is capable of operating without the optical engine installed.

In still various other embodiments, the modular frame is configured to take images, take videos, operate as a virtual assistant, record sound, or play sound when the optical engine is removed.

In still various other embodiments, the waveguide lens is configured to be removable from the modular frame and the modular frame is capable of operating without the waveguide lens installed.

Further, various embodiments are directed to a modular waveguide display device including:a waveguide lens;an optical engine; anda modular frame including:a first mechanical connector configured to connect the waveguide lens to the modular frame;a second mechanical connector configured to connect the optical engine to the modular frame; andan electrical connector which connects to a corresponding electrical connector on the optical engine allowing the modular frame to operate the optical engine,wherein, when the waveguide lens and the optical engine are mounted on the modular frame, the optical engine is configured to inject light containing image data into the waveguide lens.

In various other embodiments, the optical engine is removable from the modular frame.

In still various other embodiments, the modular frame includes at least one of a mono-camera, a stereo-camera, audio speakers, or a microphone.

In still various other embodiments, the modular frame is configured to continue operating the at least one of mono-camera, stereo-camera, audio speakers, or microphone when the optical engine is removed from the modular frame.

In still various other embodiments, the modular frame includes a battery which is configured to power both the modular frame and the optical engine.

In still various other embodiments, the second mechanical connector and the electrical connector of the modular frame is configured to accept another optical engine.

In still various other embodiments, the optical engine and the other optical engine have different features from one another.

In still various other embodiments, the first mechanical connector is configured to accept another waveguide lens.

In still various other embodiments, the waveguide lens and the other waveguide lens have different features from one another.

In still various other embodiments, the waveguide lens includes incoupling optical elements and outcoupling optical elements.

In still various other embodiments, the incoupling optical elements are configured to incouple the light containing image data from the optical engine and the outcoupling optical elements are configured to outcouple the light containing image data into a user's eye.

In still various other embodiments, the optical engine is configured to inject light into the incoupling optical elements from a side of the waveguide lens opposite to the side where the outcoupling optical elements are configured to outcouple the light containing image data into the user's eye.

In still various other embodiments, the waveguide lens is configured to be substantially optically transparent to light from the surround environment.

Further, various embodiments are directed to a modular waveguide display device including:a modular frame including:a first mechanical connector configured to connect a waveguide lens to the modular frame;a second mechanical connector configured to connect an optical engine to the modular frame; andan electrical connector configured to connect to a corresponding electrical connector on the optical engine allowing the modular frame to operate the optical engine,wherein, when the waveguide lens and the optical engine are mounted on the modular frame, the optical engine is configured to inject light containing image data into the waveguide lens.

In various other embodiments, the optical engine is removable from the modular frame.

In still various other embodiments, the modular frame includes at least one of a mono-camera, a stereo-camera, audio speakers, or a microphone.

In still various other embodiments, the modular frame is configured to continue operating the at least one of mono-camera, stereo-camera, audio speakers, or microphone when the optical engine is removed from the modular frame.

In still various other embodiments, the modular frame includes a battery which is configured to power both the modular frame and the optical engine.

In still various other embodiments, the second mechanical connector and the electrical connector of the modular frame is configured to accept another optical engine.

In still various other embodiments, the optical engine and the other optical engine have different features from one another.

In still various other embodiments, the first mechanical connector is configured to accept another waveguide lens.

In still various other embodiments, the waveguide lens and the other waveguide lens have different features from one another.

In still various other embodiments, the waveguide lens includes incoupling optical elements and outcoupling optical elements.

In still various other embodiments, the incoupling optical elements are configured to incouple the light containing image data from the optical engine and the outcoupling optical elements are configured to outcouple the light containing image data into a user's eye.

In still various other embodiments, the optical engine is configured to inject light into the incoupling optical elements from a side of the waveguide lens opposite to the side where the outcoupling optical elements are configured to outcouple the light containing image data into the user's eye.

In still various other embodiments, the waveguide lens is configured to be substantially optically transparent to light from the surround environment.

DETAILED DESCRIPTION

For the purposes of describing embodiments, some well-known features of optical technology known to those skilled in the art of optical design and visual displays have been omitted or simplified in order to not obscure the basic principles of the invention. Unless otherwise stated, the term “on-axis” in relation to a ray or a beam direction refers to propagation parallel to an axis normal to the surfaces of the optical components described in relation to the invention. In the following description the terms light, ray, beam, and direction may be used interchangeably and in association with each other to indicate the direction of propagation of electromagnetic radiation along rectilinear trajectories. The term light and illumination may be used in relation to the visible and infrared bands of the electromagnetic spectrum. Parts of the following description will be presented using terminology commonly employed by those skilled in the art of optical design. As used herein, the term grating may encompass a grating including a set of gratings in some embodiments. For illustrative purposes, it is to be understood that the drawings are not drawn to scale unless stated otherwise.

Waveguides and waveguide displays in accordance with various embodiments of the invention can be configured and implemented in many different ways. Conventionally, implementations of waveguide displays typically include bulky housing and components to accommodate various features. The components of these conventional waveguide displays are typically static and not easily changed. However, depending on the application, some features within the waveguide display may not be required or desired. This leads to unnecessary bulk that can affect the device's aesthetic and/or the user's comfort. As such, many embodiments of the invention are directed towards modular waveguide displays of which the solutions and implementations can keep bulk to a minimum for a specific application. A user is able to include only portions of the functionality which the user deems advantageous when the device is in use. Additionally, such designs can allow for the devices to be configurable by the end user to his or her aesthetic preference. Further, portions of the waveguide display may be changed based on a user's desires or based on new technology which may be released.

Further, modular waveguide displays have separate components which perform separate functions which are joined when the device is to be used. Having separate components allows for these separate components to be easily improved upon without having to adjust the entire display at any given time. This can speed up innovation within the given components which can decrease the ultimate cost and throughput of manufacture of the device. Also, the modularity of the display allows for separate components to be innovated upon by separate component manufacturers and then easily integrated into the overall device.

Referring now to the drawings, modular waveguide displays in accordance with various embodiments of the invention are illustrated. Modular waveguide displays can be implemented in many different devices, including but not limited to monocular and binocular eyewear.FIG.1is a perspective view of a modular waveguide display100implemented binocular eyewear (e.g. eyeglasses) in accordance with an embodiment of the invention. By implementing removable components, the display can be utilized for various applications while keeping bulk to a minimum. Eyeglass waveguide displays can be utilized for various applications, including but not limited to virtual reality, augmented reality, mixed reality, telepresence, and telecommunications. Eyeglass waveguide displays can also function as simple, traditional eyewear, which can include prescription and tinted lenses. In some embodiments, the waveguide display includes a removeable and/or swappable prescription insert. Device implemented for these applications, or a subset of these applications, can include removable components such that the end user can remove/include components for specific applications. Such components can also be swapped with other components for various purposes. The swappable components can allow for different choices in size, shape, material, and function. For example, the eyeglass waveguide displays may be capable of augmented reality. These eyeglass waveguide displays may include a light source or picture generation unit (e.g. a spatial light modulator).

With continued reference toFIG.1, the modular waveguide display100includes a modular frame102with an optical engine104which is configured to be attached to the modular frame102. The optical engine104is configured to be removable and swappable with other optical engines. The modular frame102may be operated without the optical engine104and still retain the functionality of the modular frame102with or without one or more waveguides106. With the light source or optical engine104removed the user may utilize the device for telepresence applications without the use of AR or VR capabilities which may reduce the size of the device and/or enhance aesthetics. In addition to being removable, such devices can also allow for swappable optical engines, which can be advantageous as different applications can have different light and/or power requirements.

In a number of embodiments, the modular frame102may include a proximity sensor, which can allow for power saving operation. For example, the proximity sensor can determine whether a user is currently wearing the device. In cases where a user is not detected, the optical engine104may be turned off to conserve power. The modular frame102may include various features such as cameras, speakers, and microphones for various features and/or to enable other applications, such as but not limited to telepresence applications. These features may be included in the modular frame102or be provided through a series of attachments. The modular waveguide display100may further include one or more waveguides106which may be attached to the modular frame102. When the optical engine104is attached to the modular frame102, the optical engine104may be configured to inject light including image data into the one or more waveguides106. The one or more waveguides106may be mounted in a waveguide frame108. As illustrated, the optical engine104may be configured to inject light into the front of the one or more waveguides106in the same side as the environment and opposite to the viewer's eyes. The waveguide frame108may have a center camera cover110or a hole which may be adapted to fit with a center camera described below.

FIG.2illustrates an exploded view of the modular waveguide display100described in connection withFIG.1. The description ofFIG.1is applicable toFIG.2and will not be repeated. As shown, the optical engine104that can be coupled to the waveguide106through an attachment slot210on top of the modular frame102. In some embodiments, the optical engine104latches onto the modular frame102to provide a flushed surface. Push spring release mechanisms can also be implemented for these latches. As can readily be appreciated, the modular waveguide display100can be designed to receive the optical engine104in different locations, the specific configuration of which can depend on the requirements of a given application. In many cases, the configuration of how the optical engine104is attached depends on the specific waveguide of the one or more waveguides106utilized.

The modular frame102may include connectors202which may electrically communicate with a corresponding electrical connectors204included on the optical engine104. The modular frame102may also include stereo cameras206mounted on opposite sides of the modular frame102. The stereo cameras206may provide for tracking such as six degrees of freedom (6DoF) tracking. The modular frame102may also include a center camera208(seen inFIG.15) which may be used to capture images and/or video for telepresence. The center camera208may be adapted for use with the center camera cover110.

The modular waveguide display100in accordance with various embodiments of the invention can incorporate other removable and/or swappable components, including but not limited to electronics, cameras, microphones, power delivery components, batteries, fail-safe mechanisms, frames, and waveguides. In many embodiments, the modular waveguide display100includes an eyetracker. In some embodiments, the modular waveguide display100includes a wired connection point for data and power delivery. For example, in a number of embodiments, one of the temples include an interface point for a Universal Serial Bus (USB) connection, such as but not limited to USB-C. In several embodiments, one of the temples includes an antenna interface. For various reasons, including safety concerns, the display can be configured to have a wired connection severed in response to accidental tugging of the wired connection. In such cases, the modular waveguide display100may be adapted to still function despite the lost in power. In many embodiments, the modular waveguide display includes a battery component, which can be removeable/swappable to allow operation of the device without a wired power delivery mechanism. In several embodiments, at least one supercapacitor is implemented to power the modular waveguide display100.

FIG.3Ais another perspective view of the modular waveguide display100described in connection withFIGS.1and2.FIG.3Bis a front view of the modular waveguide display100described in connection withFIGS.1and2.FIGS.3A and3Binclude identically numbered features to those ofFIGS.1and2. The description of identically numbered features are applicable to these figures and these descriptions will not be repeated.

AlthoughFIGS.1-3illustrate a specific implementation of the modular waveguide display100, various designs and configurations can be implemented as appropriate depending on the specific requirements of a given application. For example, different configurations can be implemented depending on the specific type of waveguide implemented. In some embodiments, the one or more waveguides106may include various waveguide technologies. The one or more waveguides106may include diffraction gratings for various functions such as input gratings (e.g. incoupling gratings), output gratings (e.g. outcoupling gratings), and/or beam expanders. These diffraction gratings may utilize Bragg gratings. Examples of waveguides incorporating Bragg gratings, waveguide display designs, and waveguide display configurations are discussed in the sections below in further detail.

Waveguides Incorporating Bragg Gratings

Optical structures recorded in waveguides can include many different types of optical elements, such as but not limited to diffraction gratings. In many embodiments, the grating implemented is a Bragg grating (also referred to as a volume grating). Bragg gratings can have high efficiency with little light being diffracted into higher orders. The relative amount of light in the diffracted and zero order can be varied by controlling the refractive index modulation of the grating, a property that is can be used to make lossy waveguide gratings for extracting light over a large pupil. One class of gratings used in holographic waveguide devices is the Switchable Bragg Grating (“SBG”). SBGs can be fabricated by first placing a thin film of a mixture of photopolymerizable monomers and liquid crystal material between glass plates or substrates. In many cases, the glass plates are in a parallel configuration. One or both glass plates can support electrodes, typically transparent tin oxide films, for applying an electric field across the film. The grating structure in an SBG can be recorded in the liquid material (often referred to as the syrup) through photopolymerization-induced phase separation using interferential exposure with a spatially periodic intensity modulation. Factors such as but not limited to control of the irradiation intensity, component volume fractions of the materials in the mixture, and exposure temperature can determine the resulting grating morphology and performance. As can readily be appreciated, a wide variety of materials and mixtures can be used depending on the specific requirements of a given application.

In many embodiments, the SBGs may include holographic polymer dispersed liquid crystal (HPDLC) material. During the recording process, the monomers polymerize and the mixture undergoes a phase separation. The LC molecules aggregate to form discrete or coalesced droplets that are periodically distributed in polymer networks on the scale of optical wavelengths. The alternating liquid crystal-rich and liquid crystal-depleted regions form the fringe planes of the grating, which can produce Bragg diffraction with a strong optical polarization resulting from the orientation ordering of the LC molecules in the droplets.

The resulting volume phase grating can exhibit very high diffraction efficiency, which can be controlled by the magnitude of the electric field applied across the film. When an electric field is applied to the grating via transparent electrodes, the natural orientation of the LC droplets can change, causing the refractive index modulation of the fringes to lower and the hologram diffraction efficiency to drop to very low levels. Typically, the electrodes are configured such that the applied electric field will be perpendicular to the substrates. In a number of embodiments, the electrodes are fabricated from indium tin oxide (“ITO”). In the OFF state with no electric field applied, the extraordinary axis of the liquid crystals generally aligns normal to the fringes. The grating thus exhibits high refractive index modulation and high diffraction efficiency for P-polarized light. When an electric field is applied to the HPDLC, the grating switches to the ON state wherein the extraordinary axes of the liquid crystal molecules align parallel to the applied field and hence perpendicular to the substrate. In the ON state, the grating exhibits lower refractive index modulation and lower diffraction efficiency for both S- and P-polarized light. Thus, the grating region no longer diffracts light. Each grating region can be divided into a multiplicity of grating elements such as for example a pixel matrix according to the function of the HPDLC device. Typically, the electrode on one substrate surface is uniform and continuous, while electrodes on the opposing substrate surface are patterned in accordance to the multiplicity of selectively switchable grating elements.

Typically, the SBG elements are switched clear in 30 μs with a longer relaxation time to switch ON. Note that the diffraction efficiency of the device can be adjusted, by means of the applied voltage, over a continuous range. In many cases, the device exhibits near 100% efficiency with no voltage applied and essentially zero efficiency with a sufficiently high voltage applied. In certain types of HPDLC devices, magnetic fields can be used to control the LC orientation. In some HPDLC applications, phase separation of the LC material from the polymer can be accomplished to such a degree that no discernible droplet structure results. An SBG can also be used as a passive grating. In this mode, its chief benefit is a uniquely high refractive index modulation. SBGs can be used to provide transmission or reflection gratings for free space applications. SBGs can be implemented as waveguide devices in which the HPDLC forms either the waveguide core or an evanescently coupled layer in proximity to the waveguide. The glass plates used to form the HPDLC cell provide a total internal reflection (“TIR”) light guiding structure. Light can be coupled out of the SBG when the switchable grating diffracts the light at an angle beyond the TIR condition.

Waveguides Incorporating Protective Layers

Waveguides and waveguide displays can include protective layers in accordance with various embodiments of the invention. In many embodiments, the waveguide or waveguide display incorporates at least one protective layer. In further embodiments, the waveguide or waveguide display incorporates two protective layers, with one on each side of the device. As discussed in the sections above, waveguides and waveguide displays can be constructed with transparent substrates that, through their air interfaces, provide a TIR light guiding structure. In those cases, the protective layer can be implemented and incorporated such that there is minimal disruption to the substrates' air interfaces. In some embodiments, the protective layer can by virtue of its material properties and/or method of deposition onto a waveguide substrate, compensate for surface defects in the substrate, such as not limited to a surface ripple, scratches, and other nonuniformities that cause the surface geometry to deviate from perfect planarity (or other desired surface geometries). Protective layers can be implemented in various thicknesses, geometries, and sizes. For example, thicker protective layers can be utilized for applications that require more durable waveguides. In many embodiments, the protective layer is sized and shaped similar to the waveguide in which it is incorporated. For curved waveguides, the protective layer can also be curved. In further embodiments, the protective layer is curved with a similar curvature as the waveguide. Protective layers in accordance with various embodiments of the invention can be made of various materials. As can readily be appreciated, the properties of the protective layer, including but not limited to thicknesses, shapes, and material compositions, can be selected based on the specific requirements of a given application. For example, protective layers can be implemented to provide structural support for various applications. In such cases, the protective layer can be made of a robust material, such as but not limited to plastics and other polymers. Depending on the application, the protective layer can also be made of glass, silica, soda lime glass, polymethyl methacrylate (PMMA), polystyrene, polyethylene, and other plastics/polymers.

In some embodiments, the protective layer can be incorporated using spacers to provide and maintain an air gap between the waveguide's substrates and the protective layers. Such spacers can be implemented similarly to those described in the sections above. For instance, a suspension of spacers and acetone can be used to spray onto the outer surface of the waveguide. In many cases, it is desirable to uniformly spray the suspension. The acetone can evaporate, leaving behind the spacers. The protective layer (which has had glue/adhesive/sealant/etc. added at the edges) can then be placed and vacuumed down into contact with the spacers. Although in some applications the spacers may move a small amount, they generally stay in place due to van der Waals forces. The spacers can be made of any of a variety of materials, including but not limited to plastics (e.g., divinylbenzene), silica, and conductive materials. In several embodiments, the material of the spacers is selected such that its refractive index does not substantially affect the propagation of light within the waveguide cell. The spacers can take any suitable geometry, including but not limited to rods and spheres. Additionally, spacers of any suitable size can be utilized. For instance, in many cases, the sizes of the spacers range from 1 to 30 μm. As can readily be appreciated, the shape and size of the spacers utilized can depend on the specific requirements of a given application. In some cases, the protective layer may advantageously be disposed further away from the waveguide. In such embodiments, larger sized spacers can be utilized.

The incorporation of protective layers can be implemented with different waveguide configurations, including single and multi-layered waveguides. For example, multi-layered waveguides can incorporate two protective layers, one disposed near each of the outer surfaces. In addition to providing environmental isolation and structural support for the waveguide, the protective layers can also be implemented for a variety of other applications. In many embodiments, the protective layer allows for dimming and/or darkening. The protective layer can incorporate materials for photochromic or thermochromic capabilities. The protective layer can also be configured to allow for controllable dimming and/or darkening. In several embodiments, the protective layer implements electrochromic capabilities. The protective layer can also provide a surface for other films, including but not limited to anti-reflective coatings and absorption filters. Such films can be implemented to avoid seeing light from the outside. In many cases, such films cannot be directly placed onto the waveguide, which can be due to the required high temperature processes or disturbance to the waveguiding in general. In many embodiments, the protective layer includes a coating that creates a mirroring effect. In some embodiments, the protective layer includes a gradual tint that is darker near the top of the lens. In a number of embodiments, the protective layer provides optical power. In further embodiments, the protective layer provides variable, tunable optical power. Such focus tunable lenses can be implemented using fluidic lenses or SBGs. In some applications, a picture generation unit is implemented and, depending on the waveguide application and design, may require an unobstructed light path between the PGU and the waveguide as the protective layer could refract the input beam, leading to positional errors. In many cases, an incident beam will contain rays that are at an angle to the waveguiding substrates. These effects will be exacerbated as the incident ray angles increase. Even for an incident beam that will not be refracted, there are still potential issues as the material used in the protective layer can impact the polarization of the beam and introduce scatter. In such embodiments, the protective layer can be designed and shaped accordingly to prevent the protective layer's interference with the light path.

Modular Waveguide Displays

Modular waveguide displays in accordance with various embodiments of the invention can be configured in many different ways, including but not limited to incorporating different levels of modularity and the type and number of components to be implemented. In many embodiments, the choice of component and how such component is implemented can depend on the specific application and/or other components. For example, waveguides incorporating different gratings and grating designs can have different requirements of how and where the light from the optical engine is coupled. In a number of embodiments, the modular waveguide display is implemented as a monocular display, with only one lens being active and coupled to a projection system. The other lens may be a dummy lens or may include functionality such as correction of vision of the user.

In some embodiments, the waveguide display is designed to have the optical engine introduce light to the front side of the waveguide (e.g. the side opposite the user's eyes).FIG.4is a diagram of a configuration where the optical engine includes a projector which introduces light to the front side of the waveguide in accordance with embodiments of the invention. Typically, in AR or VR devices, the projector is configured to introduce light from the rear side of the waveguide or the same side as the user's eyes. However, it has been discovered that introducing light from the rear side of the waveguide causes difficult alignment of the projector and the waveguides. Without limitation to any particular theory, introducing light from the rear side may cause portions of the waveguide (e.g. the incoupling optical elements and/or outcoupling optical elements) to act as mirrors which may cause difficult alignment of the projector light with the light outcoupled to the user's eye. Thus, it would be extremely beneficial when light is injected from the rear for precise alignment of the projector and the waveguide lens. However, precise alignment is difficult to implement in a modular waveguide display where the waveguide lens and the optical engine are frequently removed and swapped.

Conversely, implementing the projector on the front side of the waveguide or on the side opposite the user's eyes allows for easier alignment of the projector and the waveguide. Without limitation to any particular theory, introducing light from the front side may cause the waveguide to act as a periscope which allows a less precisely aligned projector and waveguide to function properly. Thus, implementing the projector on the front side of the waveguide allows for easy alignment of the waveguide lens and the optical engine which is beneficial for situation where the waveguide lens and the optical engine frequently removed and swapped which is the case in a modular design.FIG.4illustrates a waveguide402including an incoupling optical element404which incouples projector light410. The projector light410comes from a direction on the same side of the waveguide402as the world light408and on an opposite side of the waveguide402as the user's eye414. The waveguide402includes an outcoupling optical element414which outcouples light412including the projector light410and the world light408into the user's eye414. The implementation described in connection withFIG.4may be implemented in the design described in connection withFIGS.1-3.

Further, as can readily be appreciated, different types of optical engines104can be implemented as appropriate depending on the specific requirements of a given application. For example, the optical engine104may include projectors each including a waveguide integrated laser source. In other embodiments, an LED light source is utilized. As can readily be appreciated, various light sources and optical components, such as but not limited to prisms and collimating optics, can be utilized as appropriate depending on the specific requirements of a given application. The optical engine104may include projectors such as digital light processing (DLP) projectors, light-emitting diode (LED) projectors, liquid crystal display (LCD) projectors, or Liquid Crystal on Silicon (LCoS) projectors. The projectors may be one or more electrically switchable bragg grating (ESBG) devices which is disclosed in U.S. Pat. No. 8,224,133 entitled “LASER ILLUMINATION DEVICE” which is hereby incorporated by reference in its entirety. In some embodiments, the optical engine104can be implemented with two projectors in a single housing. Such configurations can ensure a set distance between the two projectors, which can be advantageous in many cases. In some embodiments, features are included to allow for the components to be implemented and attached to the device in a robust manner such that there are no alignment issues. In several embodiments, the components are designed to allow for a relatively high margin of misalignment. Specifically, in a number of embodiments, the waveguides are designed to still operate with a margin of misalignment to allow for robust incorporation into the device.

FIG.5Aconceptually illustrates the internal components of the optical engine104described in connection withFIGS.1-3in accordance with an embodiment of the invention. As illustrated, the optical engine104is electrically coupled to the modular waveguide display through two electrical connections202(e.g. MIPI interfaces) on either side of the eyewear frame.FIG.5Bshows an enlarged image of how the optical engine104is attached to one of the electrical connection502. The optical engine104includes connectors204which correspond to the electrical connectors202of the modular frame102to make up the electrical connections502. Connectors204of the optical engine104may include pins such as retractable pins. These retractable pins may be pogo pins. The pins may vary in length based on their different connection types in order to connect with the electrical connectors202of the modular frame102based on specific timings. The pins of the optical engine may correspond to pads of the electrical connectors202of the modular frame102. As can readily be appreciated, various other connection interfaces can be utilized as appropriate, including connections for any signals and/or power delivery for other projection systems. The optical engine module104and the one or more waveguides106are all removable/swappable from the modular frame102, which itself can be designed to be swappable for different modular frames102. In some embodiments, the modular frame102may have more or less functionality depending on the desired functionality.

FIG.6is a cross sectional view of an example implementation of the pins604a,604b,604cof the connector204of the optical engine104and their corresponding pads602a,602b,602cof the electrical connector202of the modular frame102. When the connector204of the optical engine104mates with an electrical connector204of the modular frame102, the pins604a,604b,604cconnect in an order corresponding to their height. Thus, it is advantageous to have staggered heights when it is advantageous for certain components to connect before others. In this example, a first pin604ahas a first height h1, a second pin604bhas a second height h2, and a third pin604chas a third height h3and h1>h2>h3. Thus, when the connector204is joined to the electrical connector202, the first pin604awill connect to a first pad602aof the electrical connector204followed by the second pin604bto a second pad602bof the electrical connector204, and followed by the third pin604cto a third pad602cof the electrical connector204.

In some embodiments, the first pin604amay be connected to ground, the second pin604bmay be connected to signal, and the third pin604cmay be connected to power. Thus, when the connector204is joined to the electrical connector202, the optical engine104is first connected to ground which purges the circuits within the optical engine104of any residual charge that may damage the circuits if the optical engine104was connected to power first. Next, the optical engine104is connected to signal which allows the device to be fully ready to operate before the optical engine104is connected to power. Lastly, the optical engine104is connected to power which powers the up the device only after the ground and signal have been connected. While, only one pin is shown for each of the first pin604a,the second pin604b,and the third pin604c,one of ordinary skill would recognize that there could be multiple pins of similar height corresponding to each of these pins. Further, while only three different heights are included in this example, one of ordinary skill would understand that more heights may be included to allow for sequential connection of more components. In some embodiments, the connector204may be a MIPI connector to provide adequate data bandwidth while being a standardized connector. The connector204may also be other connector types to adjust for various aspects such as bandwidth requirements.

In many embodiments, the electrical connectors202of the modular frame102allow for a variety of different components to be electrically connected to the modular waveguide display100. As discussed in the sections above, the modular waveguide display100can also operate with the optical engine104removed for reduced size and increased aesthetics. For example, if a user does not contemplate using the optical engine104functionalities during a particular session, then the modular waveguide display100may be run without the optical engine104while retaining the remaining functionality of the modular frame102and waveguides106. The modular frame102may also be run by itself without the waveguides106to further save weight when the user does not desire the functionality of the waveguides106.

FIGS.7A-7Cconceptually illustrate three different views of a modular waveguide display700in accordance with an embodiment of the invention. The modular waveguide display700is the modular waveguide display100described in connection withFIGS.1-3except operated without the optical engine104. The modular waveguide display700includes identically numbered features as those of the modular waveguide display100described in connection withFIGS.1-3. The description ofFIGS.1-3is applicable toFIGS.7A-7Cand these descriptions will not be repeated. The modular frame102includes electrical connectors202which are capable of accepting the optical engine104. In some embodiments, the electrical connectors202allow for various components, such as but not limited to the optical engine104, to be electrically connected to the eyewear device. In further embodiments, the electrical connectors202allow for the components to be electrically connected to internal electronics, such as but not limited to printed circuit boards, within the modular frame102. However, the modular waveguide display700still provides functionality without the optical engine104. For example, the modular frame102may include one or more cameras, speakers, and/or microphones which may be used to capture images, capture video, capture audio, and/or play audio. The modular frame102may be operated to provide a virtual assistant to the user. The cameras may integrate with the virtual assistant to provide audio feedback for video cues. The waveguides106may include optical correction capabilities which may be provided to the user even when the optical engine is absent. Removal of the optical engine104may decrease size, save weight, and conserve power.

FIG.8conceptually illustrates a modular waveguide display800in accordance with an embodiment of the invention. As illustrated, the modular waveguide display800is the modular waveguide display100described in connection withFIGS.1-3operated without the optical engine104and the waveguides106. The description of the modular frame102ofFIGS.1-3is applicable in the modular waveguide display700ofFIG.8. Also, the description of the modular waveguide display700ofFIG.7is applicable toFIG.8. Removal of the optical engine104and the waveguides106may save weight and power. The modular frame102may be operated alone to provide the functionality described above without the optical engine104or the waveguides106.

FIG.9conceptually illustrates an internal view of the modular frame102in accordance with an embodiment of the invention. As shown, the modular frame102houses two printed circuit boards902connected by a flex ribbon904in between. As can readily be appreciated, the electronics can be implemented as appropriated depending on the specific application. In many embodiments, the electronics provide instructions and processing power for the components with which they are connected.FIG.10conceptually illustrates an internal view of how the optical engine104is positioned with respect to the printed circuit boards902in accordance with an embodiment of the invention.

Modular components to be implemented with waveguide displays in accordance with various embodiments of the invention can be configured to be attached to the device in various ways. In many embodiments, the components are magnetically attached to the device. In some embodiments, the component is mechanically attached through latches or screws.FIG.11is an exploded view of the modular waveguide display100described in connection withFIGS.1-3. The waveguide display100includes a modular frame102, an optical engine104, and one or more waveguides106. As shown, the waveguides106may be housed in a waveguide frame108which may be attached to the modular frame102through several connection points1102dispersed through the front of the modular frame102. The connection points1102may be magnetic and the waveguide frame108may have corresponding magnetic connections. In some embodiments, there may be three connection points1102, two of which may be located at the sides of the front of the modular frame102and one of which may be located in the middle of the front of the modular frame102. While connection points1102at the two sides of the front of the modular frame102may connect the modular frame102to the waveguide frame108, it has been discovered that the third connection point1102in the center of front of the modular frame102creates more stability for the waveguides106which may be sensitive to movement. Further, there may be buttons on the side of the waveguide frame108which separate the waveguide frame108from the modular frame102and allow the waveguide frame108to be removed from the modular frame102.

Modular components allow for the possibility of swappable modules that enable the end user to select and balance for aesthetic, comfort, and performance concerns. For example, waveguide modules can often be implemented in various shapes without altering the optical functions of the waveguide. As such, the waveguide modules can be implemented in various designs to allow for different aesthetical choices for the end user.FIGS.12A-12Cconceptually illustrate a modular frame102paired with a first waveguide module1202a,a second waveguide module1202b,and a third waveguide module1202cin accordance with various embodiments of the invention. The waveguide modules1202a,1202b,1202ceach include one or more waveguides and a waveguide frame. The three different waveguide module designs may provide different aesthetic features and different functional features which may be selected based on a user's particular requirements. The user may also swap between the different waveguide modules1202a,1202b,1202cbased on a user's tastes, preferences, and utility for features at the time.FIG.12Dshows a comparison between the modular frame102paired with the first waveguide module1202a,the second waveguide module1202b,and the third waveguide module1202c.FIG.13shows a comparison between the modular frame102paired with three additional waveguide modules1302a,1302b,1302c.

In addition to providing flexibility in aesthetics and functionality, modular waveguide displays in accordance with various embodiments of the invention can provide a better fit for a wide variety of users. In many embodiments, the modular waveguide display includes various removeable and swappable components for customizing the fit for the user. For example, in some embodiments, the waveguide display includes swappable nose pads that varies in height, size, and/or shape. Such implementations can allow for a better fit across for users that may have nose features that deviates from the typical average. In several embodiments, the nose pad component is designed to mechanically attached to the modular waveguide display. In further embodiments, the nose pad components provide a further mechanical connection to a removeable nose pad frame.FIG.14illustrates a nose pad component1400in accordance with an embodiment of the invention. The nose pad component1400includes a removable nose pad frame1402which are adapted to mechanically connect to nose pads1404. The nose pad frame1402may connect to any of the modular waveguide displays discussed through this disclosure. In some embodiments, the nose pad frame1402may connect to the modular frame102. In some embodiments, the nose pad frame1402may connect to the waveguide frame108. In many embodiments, the modular frame102is locked to the nose pad frame1402with a push spring releasing mechanism. As can readily be appreciated, such components can be implemented with different sizes and shapes to accommodate a wide range of the population.

Another customization option can include removable and/or swappable ear hooks.FIG.15is an exploded view of a modular waveguide display having removable ear hooks1502in accordance with an embodiment of the invention.FIG.15includes many identically labeled features as those ofFIGS.1-3. The description ofFIGS.1-3are also applicable forFIG.15. Also,FIG.15shows the nose pad component1400described in connection withFIG.14. InFIG.15, the modular waveguide display also includes removable ear hooks1502. The removable ear hooks1502may connect into the modular frame102and hold the modular frame102on a user's face. Different ear hooks can swapped to provide a better fit depending on the user's head shape. In some embodiments, the removable ear hooks1502may be connected with a strap or band. Such components can be advantageous for various applications, including but not limited to athletics.

Depending on the application, weight distribution of the modular waveguide display can be a concern. For example, in some applications, the modular waveguide display is front-heavy. In such cases, it can be advantageous for the temples of the modular frame102to provide a greater hold on the user's head. As such, the modular frame102may include temple components with movable joints having a preload. In a number of embodiments, the temples are weighted to counteract the weight of any front components, providing adequate weight distribution for a more comfortable fit. In some embodiments, the temple can open wider than 90 degrees relative to the waveguide lens106and waveguide frame108. Such implementations can also allow for compatibility with larger head sizes.

In addition to customized fit, many modular waveguide displays are designed with various safety features. For example, as discussed above, such modular waveguide displays can include one or more batteries for providing power, or uninterrupted power as a secondary backup power source. In such embodiments, the battery(s) can be incorporated within one or both of the temple component of the modular frame102.FIG.16Ais an exploded view of a battery structure1600including a battery1604and an internal frame structure1606which can make up the temple component of the modular frame102in accordance with an embodiment of the invention.FIG.16Bis a perspective view of the battery structure1600ofFIG.16A. As shown, the internal frame structure1606can house the battery1604while only covering one side of the battery1604. This asymmetrical covering allows for a weaker point for any force to preferentially escape. By positioning the weaker side away from the user's head, such hazards can be mitigated. However, typical battery components introduce safety concerns, including but not limited to the possibilities of battery failure resulting in the battery catching on fire or exploding. Since the temple components are in proximity to the user's head, this is a critical concern. In many embodiments, the construction of the temple components and internal structures of such components are designed to mitigate potential hazards including those described above. For example, an internal frame structure1606can be provided that strengthens only the side closest to the user's head. In case of any exothermic force, the energy will be directed towards the weaker side—e.g., the side away from the user's head that is not reinforced. In several embodiments, the temple component can be constructed to be thicker on the side closer to the head for the same reasons as the implementation of the internal structure described above. As can readily be appreciated, both methods can be implemented together. The battery structure1600also includes a wiring1602which is used to connect the battery1604to the circuit boards within the modular frame102. While the wiring1602is illustrated on the side away from the head, the wiring1602may also be positioned to run along the other side.

With reference back toFIGS.1-3, another safety consideration includes the nature of the waveguides106within the modular waveguide display100. As described above, waveguides106in accordance with various embodiments of the invention can be implemented using glass substrates. In many cases, these substrates are thin and can be prone to shattering. Given that these waveguides are meant to be operated near the user's eyes, there is a potential hazard if the waveguides106were to shatter into shards. To address this issue, the waveguides106can include at least one additional layer of material on the side facing the user's eyes. This layer can be applied similarly to the protective layer as described above. In many embodiments, the additional layer includes an anti-reflective coating. In some embodiments, the additional layer is made of a robust material, such as but not limited to plastics, polymers, shatter-resistant glass, and glass substrates backed by a film.

Turning back toFIG.15, in many embodiments, the waveguide display includes at least one tracking camera206. In further embodiments, the waveguide display includes two tracking cameras206, positioned on either side of the user's head. In some applications, it is advantageous for the camera to be placed as forward as possible, with respect to the user's perspective, to allow for enough clearance such that there is no interference from any of the modular waveguide display's components to the operation of the camera206. To accommodate this, many embodiments include waveguides106shaped to allow the camera206to be placed in the same plane as the waveguide106.FIG.17Ais an exploded view of one example of a waveguide lens1700which includes waveguides1702held together by a waveguide frame108.FIG.17Bis an integrated view of the waveguide lens1700described in connection withFIG.17A. As shown, the waveguides1702are shaped to allow a camera to be placed as far forward as possible. The waveguides1702include a waveguide portion1702aand a camera portion1702b. In the illustrative embodiment, the waveguides1702includes a protective layer that covers both the waveguide portion1702aand the camera portion1702b.

The tracking cameras206can be implemented in many different ways. In a number of embodiments, the cameras206are each coupled together with a speaker to form a module. In many implementations, the camera206forms a pocket of air behind the lens. By coupling the camera206together with a speaker, the pocket can be utilized as an internal resonance cavity for the speaker. Such configurations can allow for smaller footprints compared to traditional implementations. In some embodiments, the modular frame102includes two camera/speaker modules, each positioned near a corner at which a temple connects to a main frame body. Due to the round shape of a typical user's head and the angular corners formed by the main frame body and the temples, there exist spaces in which the modules can be disposed without affecting the fit of the modular waveguide display100. By positioning the cameras206on either side of the user's head, the required distance for some applications, such as but not limited to depth perception, can be satisfied. Additionally, similarly placement for the cameras206can allow for stereo sound. In further embodiments, the waveguide display further includes an additional set of speakers disposed within the temples.

FIG.18is an exploded view of a modular frame102in accordance with an embodiment of the invention. As illustrated, the modular frame102includes a circuit board1802which includes stereo camera modules1804. The circuit board1802may also include a center camera module1806. The circuit board1802may be housed within a front module housing1808. A front plate1810encapsulates the circuit board1802within the front module housing1808. The front module housing1808connects to two temples1812. The various components and electronics of the modular waveguide display100may generate a large amount of heat. For example, the circuit board1802may support various electrical or electronic components, such as but not limited to a central processor. In a number of embodiments, the circuit board1802and processor is incorporated in the front module housing1808, which is disposed near the user's forehead when the modular waveguide display100is worn. As such, heat production can be an issue in relation to the user's comfort. In many embodiments, the front plate1810may act as a heatsink disposed on the side opposite the user's head and designed to be thermally connected with at least one of the electronic components, such as but not limited to the central processor, in order to facilitate the dissipation of heat.

In addition to the passive usage of heatsinks, the modular waveguide display100can include perforations in the modular frame102or a housing of the optical engine104. The perforations can allow for better air flow, which increases the dissipation of thermal energy due to the circulation of the ambient air. In some embodiments, perforations are placed to allow external air to flow inside the housing of the optical engine104and over one or more heat generating component, such as the central processor. This airflow path can allow for heightened cooling when the user is currently in motion, which can force more airflow over the heat generating component. In several embodiments, performance of the components can be controlled, or throttled, depending on the current operating condition. For example, the modular waveguide display100can be configured to determine, using sensors such as but not limited to inertial measurement unit sensors, whether a user is in motion and how much motion in order to throttle the performance of any electronic component as necessary (e.g. the faster the user is in motion, the more airflow and cooling is provided to the components, allowing for higher levels of performance).

FIG.19Aillustrates an exploded view of an implementation of a modular waveguide display according to an embodiment of the invention.FIG.19Bis a perspective view of the modular waveguide display ofFIG.19A. The modular waveguide display ofFIGS.19A and19Bshare identically numbered features as the modular waveguide display100ofFIGS.1-3and these features will not be repeated. The modular waveguide display may include a prescription lens1902which is configured to provide vision correction to the user. The prescription lens1902may be mounted with nose pads1904. The prescription lens1902mounted behind the waveguides106. The modular frame102may also include one or more buttons1906which allow the user to control the modular waveguide display.FIG.20illustrates an image of an example waveguide frame108mounted on a fabricated modular frame102.

Additional Features

FIGS.21-30illustrates an example embodiment including various additional features which may be present in any of the embodiments discussed above.FIG.21is a perspective view of a modular waveguide display2100in accordance with an embodiment of the invention.FIGS.22A and22Bare various exploded views of the modular waveguide display2100. The modular waveguide display2100includes a modular frame2102. The modular frame2102may be attached to an optical engine2104and one or more waveguides2106. The optical engine2104may be adapted to input light including image data into the one or more waveguides2106. The one or more waveguides2106may be mounted on a waveguide frame2108.

FIGS.23A-23Care various views of the modular waveguide display2100illustrating the presence of a retention wheel2302located on the optical engine2104. The retention wheel2302may be used to adjust the amount of tension of the which may be applied to from the optical engine2104onto the modular frame2102. Tension from the optical engine2104may produce flexion in the modular frame2102which may flex the waveguide frame2108which thus flexes the one or more waveguides2106. Optimizing the amount of tension placed on the modular frame2102may limit the amount of flex within the one or more waveguides2106which may be extremely sensitive to the amount of warpage. The retention wheel2302may be adjusted through a user's thumb or other fingers.

FIG.24is a view of the modular waveguide display2100illustrating the presence of a nose clip2402mounted on the modular frame2102. When a user wears the modular waveguide display2100the nose clip2402contacts the nose. As illustrated, the nose clip includes multiple places of contact at multiple locations of the nose which may improve balance of the modular waveguide display2100on the user's nose. While weight is minimized in the modular waveguide display2100, this device tends to be heavier than traditional eyeglasses and thus the updated nose clip2402allows the user's nose to properly balance the additional weight.

FIG.25is a perspective view of a housing2502which encapsulates the optical engine2104in accordance with an embodiment of the invention. The housing2502may protect the internal components of the optical engine2104such as the projectors. The housing2502may include ribs2504placed in the interior portion of the housing2502. The ribs2504may improve the strength of the housing2502which allow the housing2502to better protect the optical engine.

FIGS.26A-26Care various views of the modular waveguide display2100illustrating the presence of an alignment ball2602in the optical engine2104. The alignment ball2602may be used to align components2604of projectors. During operation, the components2604of the projector affect various properties (e.g. directionality) of the light transmitted into the one or more waveguides2606. The alignment ball2602may be used to align the light transmitted into the one or more waveguides2606. Because of the modularity of the modular waveguide display2100, the alignment of the optical engine2104and one or more waveguides2606may change depending on how the components are mounted and swapped components with different properties. Thus, the alignment ball2602may help keep the one or more waveguides2606in proper alignment with the projectors in the optical engine2104. The alignment ball2602may be a gimbal bearing. The alignment ball2602may be on one or both sides of the optical engine2604.

FIG.27is a perspective view of the modular waveguide display2100without the optical engine2104installed and illustrating aspects of the retention mechanism which retains the waveguide frame2108on the modular frame2102. As illustrated, the waveguide frame2108may include a slide clip2702which may be used to release the center retaining mechanism from the modular frame2102. The slide clip2702may be located in the center of the waveguide frame2108.FIG.28Aillustrates an enlarged view of the slide clip2702andFIG.28Billustrates a cross-sectional view of the waveguide frame2108mounted on the modular frame2102. The cross-sectional view goes through the slide clip2702showing the internal mechanism of the slide clip2702.

Turning back toFIG.27, the modular frame2102may also include one or more release buttons2704which may be used to release one or more connections of the modular frame2102to the waveguide frame2108.FIG.29Aillustrates a cross-sectional view of the waveguide frame2108mounted on the modular frame2102going through the release button2704and showing one or more springs2902located on the waveguide frame2108. The springs2902may include a bracket2904which may increase the directionality of the movement of the springs2902. When the release button2704is activated, the springs2902may work in conjunction with the bracket2904to separate the waveguide frame2108from the modular frame2102.FIG.29Bis a view of the waveguide frame2108mounted on the modular frame2102illustrating the positioning of the springs2902and the bracket2904.FIGS.30A and30Bare various views of the waveguide frame2108illustrating the springs2902and the bracket2904.

As discussed previously, all the additional features discussed in connection withFIGS.21-30may be applicable to devices discussed throughout this disclosure. For example, the additional features ofFIGS.21-30may also be implemented in the devices discussed in connection withFIGS.1-20.

Doctrine of Equivalents

While the above description contains many specific embodiments of the invention, these should not be construed as limitations on the scope of the invention, but rather as an example of one embodiment thereof. It is therefore to be understood that the present invention may be practiced in ways other than specifically described, without departing from the scope and spirit of the present invention. Thus, embodiments of the present invention should be considered in all respects as illustrative and not restrictive. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their equivalents.