Patent Application
20140240842
Near-eye display devices may utilize various optical technologies to deliver an image to an eye of a user. For example, a near-eye augmented reality display may utilize one or more waveguides incorporated into a see-through display configured to be positioned in front of a user's eye(s). In such a device, the waveguide may receive an image from a microdisplay at an input coupling of the waveguide, and transmits the image to an output coupling configured to direct the image toward a user's eye.
Various embodiments are disclosed herein that relate to coupling light into waveguides in a near-eye display device in a manner configured to be tolerant to misalignment of the waveguides with each other and/or other optics. For example, one disclosed embodiment provides a near-eye display device comprising one or more waveguides, wherein each waveguide comprises a light input coupling configured to receive light at a first side of the waveguide to couple the light into the waveguide, and a light output coupling configured to emit light from the waveguide at a second side of the waveguide, the second side of the waveguide being opposite the first side of the waveguide.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.
As mentioned above, a near-eye display may utilize one or more waveguides incorporated into a display (see-through or otherwise) configured to be positioned in front of a user's eye or eyes. In such a device, the waveguide may receive an image from a microdisplay at an input coupling, and transmit the image to an output coupling configured to direct the image toward a user's eye.
A color near-eye display may utilize a stack of waveguides to display color images, such that a separate waveguide is utilized for each color. Additionally, multiple waveguides may be provided for each color to provide a wider field of view for each color than may be achieved with one waveguide for each color. However, as described in more detail below, misalignment of a waveguide in a waveguide stack with other waveguides in the stack and/or other optics (such as projection optics) may give rise to additive errors in an angle of the light output by the waveguide. Such errors may be detected by the human eye if the departure from parallel between two waveguides is larger than the visual resolution of the human eye. Small errors (e.g. waveguides angularly offset from each other by ½ to 1 arcmin from parallel) may appear as blurred images, while larger errors (e.g. greater than 1 arcmin) may appear as multiple images.
Accordingly, embodiments are disclosed that relate to waveguide displays with less sensitivity to such alignment errors due to the input and output couplings of each waveguide being at opposite sides of the waveguide. In such a display, errors due to misalignment may substantially cancel, rather than increase additively at each coupling.
Prior to discussing such embodiments in detail, an example embodiment of a use environment 100 for a near-eye display device 102 is described with reference to
In the depicted example, the near-eye display device 102 is displaying augmenting imagery in the form of one or more virtual objects 105 pertaining to information regarding one or more objects in the environment 100. The displayed information may be obtained in any suitable manner. For example, the displayed information may be stored locally on the near-eye display device 102, may be retrieved from a remote service 106 and database 108 via a network 112, and/or may be received in any other suitable manner
The light source 202 may project light onto one or more microdisplays 204. In some embodiments, a single microdisplay may be used to generate images in a color field-sequential manner, while in other embodiments, separate microdisplays may be used for each color to allow the simultaneous display of colors. Further, in some embodiments, a separate microdisplay (or arrangement of plural microdisplays) may be used for each eye. Any suitable type of microdisplay may be used, including but not limited to one or more liquid crystal on silicon (LCOS) microdisplays. In yet other embodiments, one or more emissive microdisplays may be used (e.g. an organic light-emitting device microdisplay), such that light source 202 may be omitted.
A controller 206 may send control signals to the light source 202 and the microdisplay 204 to control the display of an image via the microdisplay 204. Light from the microdisplay may then be coupled into a waveguide stack 208 for delivery to an eye 210 of a user. The waveguide stack 208 includes a plurality of waveguides, such as separate waveguides for different colors (e.g. red, green and blue), as shown at 212. Further, in some embodiments, multiple waveguides may be provided for each color to help provide a wider field of view for each color than may be achieved with one waveguide for each color. It will be understood that these embodiments are described for the purpose of example, and are not intended to be limiting in any manner. For example, a single color display may utilize a single waveguide.
In contrast,
It will be understood that the input couplings 502a, 502b and the output couplings 504a, 504b may couple light into and out of the waveguides 500a, 500b in any suitable manner, such as via diffractive and/or reflective mechanisms. It further will be understood that the mitigating effects of locating the input and output couplings on opposite sides of the waveguide may be greatest when a prescription of the input coupling and the output coupling are the same. However, in some embodiments, the input coupling and output coupling may have different prescriptions where suitable.
Light may be delivered to the input coupling in any suitable manner. For example, in some embodiments, light may be delivered from a light source (e.g. a emissive microdisplay or spatial light modulating microdisplay) at the same side of the waveguide(s) as a user's eye to an input coupling(s) at an opposite side of the waveguide(s). In such an embodiment, one or more reflective structures may be used to receive light from around an edge of the waveguide(s) and to reflect the light back toward the input coupling(s). It will be understood that the term “reflective structure” represents any suitable structure for reflecting light, including but not limited to metallic mirrors, multilayer dielectric minors, total internal reflection elements, etc.
In addition to mitigating errors caused by waveguide misalignment, locating input and output couplings of a waveguide display on opposite sides of a waveguide also may help to correct for misalignments of a waveguide with respect to other optics in an optical system. For example,
In contrast, in a waveguide having input and output couplings on opposite sides of the waveguide, the angular offset introduced at the input coupling is mitigated by the angular offset at the output coupling, such that light exits the waveguide in an intended direction.
Method 900 comprises, at 902, directing light from a light source (e.g. an image producing element) into an input coupling located at a first side of the waveguide. As depicted, the coupling may comprise one or more of a reflective coupling 904 and a diffractive coupling 906. Where the waveguide display comprises a stack of multiple waveguides, light may be coupled into each waveguide of the stack of waveguides via diffractive and/or reflective mechanisms.
In some embodiments, the light source may be at a same side of the waveguide display as a user's eye. Thus, in such embodiments, method 900 may further comprise directing light around an edge of the waveguide, as indicated at 908, in order to couple the light into the waveguide at the input coupling. Any suitable reflective structure or structures may be used. Examples include, but are not limited to, minors, multilayer dielectric minors, and total internal reflection structures.
Continuing, method 900 next comprises, at 910, directing light from the input coupling, through the waveguide, and then out of the waveguide via an output coupling at a second, opposite side of the waveguide as the waveguide input coupling. In this manner, errors that may arise from misalignment of waveguides with each other (e.g. where waveguides in a waveguides stack are not parallel) and/or misalignment of the waveguide(s) with other optics, such as projection optics, may be mitigated compared to a waveguide with input and output couplings at a same side.
Computing system 1000 includes a logic machine 1002 and a storage machine 1004. Computing system 1000 may also include a display subsystem 1006, input subsystem 1008, communication subsystem 1010, and/or other components not shown in
Logic machine 1002 includes one or more physical devices configured to execute instructions. For example, the logic machine may be configured to execute machine-readable instructions that are part of one or more applications, services, programs, routines, libraries, objects, components, data structures, or other logical constructs. Such instructions may be implemented to perform a task, implement a data type, transform the state of one or more components, achieve a technical effect, or otherwise arrive at a desired result.
The logic machine may include one or more processors configured to execute software instructions. Additionally or alternatively, the logic machine may include one or more hardware or firmware logic machines configured to execute hardware or firmware instructions. Processors of the logic machine may be single-core or multi-core, and the instructions executed thereon may be configured for sequential, parallel, and/or distributed processing. Individual components of the logic machine optionally may be distributed among two or more separate devices, which may be remotely located and/or configured for coordinated processing. Aspects of the logic machine may be virtualized and executed by remotely accessible, networked computing devices configured in a cloud-computing configuration.
Storage machine 1004 includes one or more physical devices configured to hold instructions executable by the logic machine to implement the methods and processes described herein. For example, controller 206 of
Storage machine 1004 may include removable and/or built-in devices. Storage machine 1004 may include optical memory (e.g., CD, DVD, HD-DVD, Blu-Ray Disc, etc.), semiconductor memory (e.g., RAM, EPROM, EEPROM, etc.), and/or magnetic memory (e.g., hard-disk drive, floppy-disk drive, tape drive, MRAM, etc.), among others. Storage machine 1004 may include volatile, nonvolatile, dynamic, static, read/write, read-only, random-access, sequential-access, location-addressable, file-addressable, and/or content-addressable devices.
It will be appreciated that storage machine 1004 includes one or more physical devices. However, aspects of the instructions described herein alternatively may be propagated by a communication medium as a signal (e.g., an electromagnetic signal, an optical signal, etc.), as opposed to being stored on a physical device.
Aspects of logic machine 1002 and storage machine 1004 may be integrated together into one or more hardware-logic components. Such hardware-logic components may include field-programmable gate arrays (FPGAs), program- and application-specific integrated circuits (PASIC/ASICs), program- and application-specific standard products (PSSP/ASSPs), system-on-a-chip (SOC), and complex programmable logic devices (CPLDs), for example.
When included, display subsystem 1006 may be used to present a visual representation of data held by storage machine 1004. This visual representation may take the form of a graphical user interface (GUI). As the herein described methods and processes change the data held by the storage machine, and thus transform the state of the storage machine, the state of display subsystem 1006 may likewise be transformed to visually represent changes in the underlying data. Display subsystem 1006 may include one or more display devices utilizing virtually any type of technology, including but not limited to the near-eye display systems described herein. Such display devices may be combined with logic machine 1002 and/or storage machine 1004 in a shared enclosure, or such display devices may be peripheral display devices.
When included, input subsystem 1008 may comprise or interface with one or more user-input devices such as a keyboard, mouse, touch screen, microphone, or game controller. In some embodiments, the input subsystem may comprise or interface with selected natural user input (NUI) componentry. Such componentry may be integrated or peripheral, and the transduction and/or processing of input actions may be handled on- or off-board. Example NUI componentry may include a microphone for speech and/or voice recognition; an infrared, color, stereoscopic, and/or depth camera for machine vision and/or gesture recognition; a head tracker, eye tracker, accelerometer, and/or gyroscope for motion detection and/or intent recognition; as well as electric-field sensing componentry for assessing brain activity.
When included, communication subsystem 1010 may be configured to communicatively couple computing system 1000 with one or more other computing devices. Communication subsystem 1010 may include wired and/or wireless communication devices compatible with one or more different communication protocols. As non-limiting examples, the communication subsystem may be configured for communication via a wireless telephone network, or a wired or wireless local- or wide-area network. In some embodiments, the communication subsystem may allow computing system 1000 to send and/or receive messages to and/or from other devices via a network such as the Internet.
It will be understood that the configurations and/or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. As such, various acts illustrated and/or described may be performed in the sequence illustrated and/or described, in other sequences, in parallel, or omitted. Likewise, the order of the above-described processes may be changed.
The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof.
