This disclosure relates generally to optics, and in particular to dimming and polarization.
A smart device is an electronic device that typically communicates with other devices or networks. In some situations the smart device may be configured to operate interactively with a user. A smart device may be designed to support a variety of form factors, such as a head mounted device, a head mounted display (HMD), or a smart display, just to name a few.
Smart devices may include one or more components for use in a variety of applications, such as gaming, aviation, engineering, medicine, entertainment, video/audio chat, activity tracking, and so on. In some examples, a smart device may include one or more optical elements.
Non-limiting and non-exhaustive embodiments of the invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.
Embodiments of switchable polarizer are described herein. In the following description, numerous specific details are set forth to provide a thorough understanding of the embodiments. One skilled in the relevant art will recognize, however, that the techniques described herein can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects.
Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
In some implementations of the disclosure, the term “near-eye” may be defined as including an element that is configured to be placed within 50 mm of an eye of a user while a near-eye device is being utilized. Therefore, a “near-eye optical element” or a “near-eye system” would include one or more elements configured to be placed within 50 mm of the eye of the user.
In aspects of this disclosure, visible light may be defined as having a wavelength range of approximately 380 nm-700 nm. Non-visible light may be defined as light having wavelengths that are outside the visible light range, such as ultraviolet light and infrared light. Infrared light having a wavelength range of approximately 700 nm-1 mm includes near-infrared light. In aspects of this disclosure, near-infrared light may be defined as having a wavelength range of approximately 700 nm-1.4 μm.
In aspects of this disclosure, the term “transparent” may be defined as having greater than 90% transmission of light. In some aspects, the term “transparent” may be defined as a material having greater than 90% transmission of visible light.
Conventional polarizers are one type of dimming option for optical elements. However, conventional polarizers typically cannot exceed 50% transmission of unpolarized light. Aspects of the present disclosure provide a switchable polarizer for active dimming in an optical element. Some switchable polarizers of this disclosure have greater than 50% light transmission in the transmissive state. In some aspects, the switchable polarizer may also allow different dark state levels, as opposed to a binary clear/dark state.
In implementations of the disclosure, a switchable polarizer includes a metal layer and a transparent conductor layer. When a first voltage level is applied to the transparent conductor layer, strips of the metal layers form chains that linearly polarize light. In a transmissive state of the switchable polarizer, a second voltage level is applied to the transparent conductor layer and the strips of the metal layers curl which breaks the chains and reduces a cross-section of the strips with respect to incident light. This may allow for a device that can switch between (1) behaving like a wire-grid polarizer and (2) behaving like a slightly-tinted window. In some implementations, a head mounted device (e.g. glasses) includes a switchable polarizer that can be activated to selectively reduce glare (e.g. light reflecting off of water) without substantially dimming other scene light.
The illustrated example of head-mounted device 100 is shown as including a frame 102, temple arms 104A and 104B, and near-eye optical elements 110A and 110B.
In some implementations, near-eye optical elements 110A/110B may each include one or more optical layers and/or coatings. For example, near-eye optical element 110A may include an illumination layer, an optical combiner layer, a lens, a filter layer, and so on. The optional illumination layer may include one or more in-field light sources that are configured to emit non-visible light towards the eyeward side 109 for eye-tracking purposes. In other examples, head mounted device 100 may include one or more light sources disposed outside the field-of-view of the user, such around a periphery of the near-eye optical element 110A (e.g., incorporated within or near the rim of frame 102).
An optional filter layer of the near-eye optical element 110A may be configured to block non-visible light received from the backside 111. The optional lens of the near-eye optical element may have a curvature for focusing light (e.g., display light and/or scene light) to the eye of the user. The near-eye optical element 110A may also include an optional optical combiner layer that is configured to receive display light that is generated by a digital display and to direct the display light towards the eyeward side 109 for presentation to the user. In some aspects, the optical combiner layer is transmissive to visible light, such as scene light 191 incident on the backside 111 of the near-eye optical element 110A. In some examples, the optical combiner layer may be configured as a volume hologram and/or may include one or more diffraction gratings (e.g., Bragg, blazed, uniform, etc.) for directing the display light towards the eyeward side 109.
As shown in
A switchable polarizer, such as described herein, may be included in the near-eye optical element 110A and/or near-eye optical element 110B, in accordance with aspects of the present disclosure. A switchable polarizer may be used as a switchable global dimming element in near-eye optical element(s) 110. In some implementations, switchable pixels are incorporated into near-eye optical element(s) 110 where each pixel (or zone of pixels) is a switchable polarizer to provide polarization and/or dimming of particular pixels or zones of pixels in the near-eye optical element(s) 110.
Transparent conductor layer 220 is configured to receive the switching signal 273. Transparent conductor layer 220 may include indium tin oxide (ITO) or other suitable transparent conductor. Transparent insulator layer 230 may be a transparent dioxide such as silicon dioxide. Transparent insulator layer 230 electrically isolates transparent conductor 220 from both adhesion layer 240 and metal layer 250.
Adhesion layer 240 may be an adhesive configured to bond metal layer 250 to transparent insulator layer 230. Metal layer 250 may be patterned to define metal strips that curl and uncurl (extend). Metal layer 250 may be made from (or include) chromium. Adhesion layer 240 may also be patterned to include voids 243 that allow portions of the strips of metal layer 250 to curl and uncurl (extend) in response to switching signal 273 (without the strips being adhered to the rest of optical structure 201). Adhesion layer 240 is disposed between metal layer 250 and transparent insulator 230, in the illustrated implementation of
In implementations of the disclosure, an optical element in the curled state may be approximately 90% transmissive. In some implementations, the curled state transmits the majority of incident light 299. Thus, the curled state of metal layer 250 may be referred to as the transmissive state of an optical element in this disclosure since the cross-section of the metal layer is reduced with respect to incoming incident light. In implementations of the disclosure, an optical element in the extended state would be approximately 15% transmissive. In some implementations, the extended state is approximately 40% transmissive. In some implementations, the extended state is approximately 50% transmissive. Thus, the extended state of the metal layer 250 may be referred to as the dark state of an optical element in this disclosure since the cross-section of the metal layer is increased with respect to incoming incident light. Furthermore, when metal strips 453 also form a plurality of chains (e.g. 481, 482, 483) that allow the optical element to function as a polarizer, the extended state of metal layer 250 may be referred to as the polarizing state of an optical element in this disclosure since the extended strips may form the chains that linearly polarize incident light 299. In implementations where strips 453 extend to form polarization chains 481, the extended state of strips 453 of metal layer 250 may be referred to as a dark state and a polarizing state.
By way of example, in frame 708, signal 709 is voltage-level high for 50% of frame 708 and voltage-level low for 50% of the frame. Thus, the average transmission, in the frame time period, will be half way between the transmission of incident light in the transmissive state and the dark state. If the dark state is 20% transmissive and the transmissive state is 80% transmissive, the average light transmission in frame 708 will be approximately 50%. Pixel P6 may be driven to 50% transmission, for example.
In frame 707, signal 709 is voltage-level high (dark state) for 25% of frame 707 and voltage-level low (transmissive state) for 75% of the frame. If the dark state is 20% transmissive and the transmissive state is 80% transmissive, the average light transmission in frame 707 will be approximately 65%. Pixel P7 may be driven to 65% transmission, for example.
In frame 706, signal 709 is voltage-level high (dark state) for 80% of frame 706 and voltage-level low (transmissive state) for 20% of the frame. If the dark state is 20% transmissive and the transmissive state is 80% transmissive, the average light transmission in frame 707 will be approximately 32%. Pixel P5 may be driven to 32% transmission, for example.
Thus, frames 706, 707, and 708 are examples of modulating a signal 709 to switch a metal layer 250 of an optical structure 201 of a pixel between an extended state and a curled state to tune an average percentage of incident light that propagates through a pixel of the optical device. Of course, the example frames in
In operation, the pixelated switchable polarization rotating layer 972 is driven to control the polarization state of the output light propagating towards switchable polarizer 973. For the pixels that are to appear dark, the pixels in pixelated switchable polarization-rotating layer 972 are driven so that the polarization orientation of the output light for a particular pixel are absorbed by the switchable polarizer 973.
Embodiments of the invention may include or be implemented in conjunction with an artificial reality system. Artificial reality is a form of reality that has been adjusted in some manner before presentation to a user, which may include, e.g., a virtual reality (VR), an augmented reality (AR), a mixed reality (MR), a hybrid reality, or some combination and/or derivatives thereof. Artificial reality content may include completely generated content or generated content combined with captured (e.g., real-world) content. The artificial reality content may include video, audio, haptic feedback, or some combination thereof, and any of which may be presented in a single channel or in multiple channels (such as stereo video that produces a three-dimensional effect to the viewer). Additionally, in some embodiments, artificial reality may also be associated with applications, products, accessories, services, or some combination thereof, that are used to, e.g., create content in an artificial reality and/or are otherwise used in (e.g., perform activities in) an artificial reality. The artificial reality system that provides the artificial reality content may be implemented on various platforms, including a head-mounted display (HMD) connected to a host computer system, a standalone HMD, a mobile device or computing system, or any other hardware platform capable of providing artificial reality content to one or more viewers.
The term “processing logic” in this disclosure may include one or more processors, microprocessors, multi-core processors, Application-specific integrated circuits (ASIC), and/or Field Programmable Gate Arrays (FPGAs) to execute operations disclosed herein. In some embodiments, memories (not illustrated) are integrated into the processing logic to store instructions to execute operations and/or store data. Processing logic may also include analog or digital circuitry to perform the operations in accordance with embodiments of the disclosure.
A “memory” or “memories” described in this disclosure may include one or more volatile or non-volatile memory architectures. The “memory” or “memories” may be removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules, or other data. Example memory technologies may include RAM, ROM, EEPROM, flash memory, CD-ROM, digital versatile disks (DVD), high-definition multimedia/data storage disks, or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information for access by a computing device.
Networks may include any network or network system such as, but not limited to, the following: a peer-to-peer network; a Local Area Network (LAN); a Wide Area Network (WAN); a public network, such as the Internet; a private network; a cellular network; a wireless network; a wired network; a wireless and wired combination network; and a satellite network.
Communication channels may include or be routed through one or more wired or wireless communication utilizing IEEE 802.11 protocols, BlueTooth, SPI (Serial Peripheral Interface), I2C (Inter-Integrated Circuit), USB (Universal Serial Port), CAN (Controller Area Network), cellular data protocols (e.g. 3G, 4G, LTE, 5G), optical communication networks, Internet Service Providers (ISPs), a peer-to-peer network, a Local Area Network (LAN), a Wide Area Network (WAN), a public network (e.g. “the Internet”), a private network, a satellite network, or otherwise.
A computing device may include a desktop computer, a laptop computer, a tablet, a phablet, a smartphone, a feature phone, a server computer, or otherwise. A server computer may be located remotely in a data center or be stored locally.
The processes explained above are described in terms of computer software and hardware. The techniques described may constitute machine-executable instructions embodied within a tangible or non-transitory machine (e.g., computer) readable storage medium, that when executed by a machine will cause the machine to perform the operations described. Additionally, the processes may be embodied within hardware, such as an application specific integrated circuit (“ASIC”) or otherwise.
A tangible non-transitory machine-readable storage medium includes any mechanism that provides (i.e., stores) information in a form accessible by a machine (e.g., a computer, network device, personal digital assistant, manufacturing tool, any device with a set of one or more processors, etc.). For example, a machine-readable storage medium includes recordable/non-recordable media (e.g., read only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.).
The above description of illustrated embodiments of the invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize.
These modifications can be made to the invention in light of the above detailed description. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.
This application claims priority to U.S. provisional Application No. 63/050,649 filed Jul. 10, 2020, which is hereby incorporated by reference.
Number | Date | Country | |
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63050649 | Jul 2020 | US |