Eye detection method and apparatus

Abstract

The present disclosure relates to eye detection methods and devices. A head-mounted device has a plurality of electrodes configured to detect optical events, such as movement of one or more eyes or a coarse eye pose. In some examples, the one or more electrodes can be coupled to dielectric elastomer materials whose shape can be changed to change contact between a user of the head-mounted device and the one or more electrodes to ensure adequate contact and adequate electrode signal quality. In some examples, the one or more electrodes can be coupled to pressure sensors and control circuitry to monitor and adjust applied pressure. In some examples, the optical events can be used as triggers for operating the device, including transitioning between operating power modes. In some examples, the triggers can invoke higher resolution sensing capabilities of the head-mounted device. In some examples, the electrodes can be used as on-head detectors for waking up and / or unlocking the device.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Patent Application No. 17 / 448,873, filed September 24, 2021, the contents of which are incorporated herein by reference in their entirety for all purposes. Background Technology

[0003] Some devices offer eye-tracking systems for human-computer interaction. In some applications, devices capture a user's eye movements and use these movements as intuitive input to operate the device and evoke its features, thus allowing for faster and more efficient interaction. There is a desire for devices that reduce interaction conflicts between users and devices. Summary of the Invention

[0004] Some examples of this disclosure relate to a head-mounted device having multiple electrodes configured to detect optical events, such as movement or coarse eye posture of one or more eyes. In some examples, the one or more electrodes may be coupled to a dielectric elastomer material whose shape is changeable to alter the contact between the user of the head-mounted device and the one or more electrodes, ensuring sufficient contact and adequate electrode signal quality. In some examples, the one or more electrodes may be coupled to a pressure sensor and control circuitry to monitor and adjust applied pressure. In some examples, these optical events may serve as triggers for operating the device, including transitions between operating power modes. In some examples, these triggers may activate the head-mounted device's higher resolution sensing capabilities. In some examples, these electrodes may serve as head-mounted detectors for waking up and / or unlocking the device. Attached Figure Description

[0005] Figure 1 A symbolic hardware diagram of a system for detecting eye events according to some embodiments of this disclosure is shown.

[0006] Figure 2 A functional block diagram of a system for detecting eye events according to some embodiments of the present disclosure is shown.

[0007] Figure 3 Multiple electrodes for detecting eye events are shown in locations around a user’s face and head, according to an example of this disclosure.

[0008] Figure 4 An exemplary electrode configuration according to an example of this disclosure is shown, which includes a spring-loaded needle element to improve coupling between the electrode and tissue.

[0009] Figure 5AAn exemplary electrode configuration according to an example of this disclosure is shown, which includes one or more elements in an inactive state, but which may be activated to improve coupling between the electrode and the tissue.

[0010] Figure 5B Examples according to this disclosure are shown. Figure 5A An exemplary electrode configuration includes one or more elements in an activated state to improve coupling between the electrode and tissue.

[0011] Figure 6A An exemplary electrode configuration according to an example of this disclosure is shown, which includes one or more elements in an inactive state, but which may be activated to improve coupling between the electrode and tissue. In addition, the exemplary electrode configuration includes a pressure sensor co-located with the electrode.

[0012] Figure 6B Examples according to this disclosure are shown. Figure 6A An exemplary electrode and pressure sensor configuration is provided, which is activated to improve coupling between the electrode and the tissue.

[0013] Figure 6C A feedback control system for adjusting the amount of pressure applied to tissue by an electrode, according to some examples of this disclosure, is shown.

[0014] Figure 7 Exemplary signal processing of the counter electrode signal according to some embodiments of the present disclosure is shown.

[0015] Figure 8 Exemplary electrodes and analog front-ends for processing electrode signals are shown according to some embodiments of the present disclosure.

[0016] Figure 9 Examples of sensor data associated with a head-mounted device are shown, according to some examples of this disclosure.

[0017] Figure 10 Methods for reducing power consumption in eye tracking according to some examples of this disclosure are shown. Detailed Implementation

[0018] In the following description of the examples, reference will be made to the accompanying drawings, which form part of the following description, and specific examples that can be implemented are shown by way of example in the drawings. It should be understood that other examples and structural changes may be used without departing from the scope of the disclosed examples.

[0019] As computer input technology continues to evolve, advancements in input devices allow users to interact with computing systems more efficiently. Head-mounted devices, including elements configured to detect eye movement, are an example of inventions that can further improve the speed, efficiency, and ease with which users can interact with one or more computing systems. In some implementations, a user's gaze can be detected to seamlessly invoke device functionality. For example, even when the user's hands are otherwise occupied, one or more eye events (e.g., blinking, eye focusing, and / or gaze movement) can be monitored to wake and / or unlock the device. Gaze estimation can also be used for eye pose recognition, providing input to various user interfaces (such as selecting or switching between settings) and providing input shortcuts. In addition or alternatively, gaze focusing and / or movement can be used as triggers to switch the device and / or system from a lower-power operating mode to a higher-power operating mode to reduce computational complexity and extend the device's battery life. As mentioned herein, eye events can include one or more blinks, fixations, and / or saccades. It should also be understood that eye events can include sequences of one or more eye events (e.g., a sequence of one or more blinks, gazes, and / or saccades in some combination). Other use cases for the detection of eye events include head-mounted device recognition (e.g., sensing devices being worn on a user's head and turned on), accessibility for people with disabilities, and eye health.

[0020] In some embodiments, the head-mounted device may include electrodes configured to monitor electrical pulses corresponding to eye events. For example, electrodes coupled to a dielectric elastomer (DE) material may be arranged around characteristic features of the body, including but not limited to those in contact with and / or above the nose, behind and / or around the ears, temples, and / or any other location suitable for detecting and capturing electrical pulses associated with one or more eye events or other brain-related events and neural activity.

[0021] Figure 1 Symbolic hardware diagrams of a system 100 for detecting eye events according to some embodiments of this disclosure are shown. In some embodiments, system 100 may include a portable device 102, which may be a wearable device such as glasses, goggles, a sun visor, a face mask, a helmet, or other head-mounted device. In some embodiments, device 102 may be communicatively coupled to device 104, which may be a smartphone, tablet computer, laptop computer, auxiliary device for communicating with another device, wearable host device, etc. In some embodiments, device 102 may, in addition to or alternatively, be communicatively coupled to one or more devices 106, which may be accessory devices such as laser pointers, handheld touch controllers, gloves, etc. In some embodiments, system 100 may include only a single device 102 (and optional accessory devices 106), wherein device 102 includes the functionality of device 104.

[0022] In some embodiments, multiple electrodes and associated circuitry (not shown) may be located on or within device 102 such that, when the device is worn on a user's head, the electrodes contact selected areas of the user's head at the eyes, nose, temples, and / or ears. The voltage difference between the electrodes can be measured to detect electrical impulses associated with one or more eye events, such as movement of the user's gaze (the location where the user's eyes are focused). Specific operations can be initiated when the user's gaze is associated with a specific area or object within a computer-generated environment or physical environment, or with a specific user interface display within a computer-generated environment. In various embodiments, the computer-generated environment may be presented on a display or surface within device 102 (e.g., on glasses or a head-mounted device) or on a display or surface within device 104 (e.g., on a display of a computing device).

[0023] Figure 2 A functional block diagram of a system 200 for detecting eye events according to some embodiments of the present disclosure is shown. In some embodiments, system 200 may be at least partially incorporated into device 202 (portable device), which may be a wearable device such as glasses, goggles, visors, face shields, helmets, or other head-mounted devices. A plurality of electrodes 208 may be located on device 202 for detecting electrical pulses associated with one or more eye events. These electrical pulses may be detected by measuring the voltage difference between the electrodes using receiver 216 and may be converted into digital signals via analog-to-digital converter (ADC) 220. In some embodiments, a plurality of elastomers 210 may be attached to electrodes 208 to help the electrodes make better contact with the user's skin. In one example, actuator 212 may apply a stimulating voltage (e.g., DC, AC, and / or some combination thereof) to elastomers 210, which may cause the elastomers to deform in response to the applied electric field and cause electrodes 208 to apply increased pressure to the user's skin. In some embodiments, pressure sensor 214 may be used near electrodes 208 to detect the pressure applied to the user's skin. The electrical signal from pressure sensor 214 can be received by receiver 218 and converted into a digital signal via ADC 222. Controller 226 can be coupled to one or more ADCs 220 and 222 to receive and / or process the digitized signals from electrode 208 and pressure sensor 214. Pressure information received from pressure sensor 214 can be processed by controller 226 to determine the update voltage to be applied by driver 212. In this way, a feedback loop can be created to maintain appropriate pressure on electrode 208 for the user.

[0024] In some embodiments, the driver 212, receivers 216 and 218, ADCs 220 and 222, and controller 226 may constitute the analog front-end (AFE) 224 of the elastomer 210, electrode 208, and pressure sensor 214, and may be partially or completely integrated into a single package (e.g., within an integrated circuit and / or system-on-a-chip). However, the embodiments described with respect to the front-end circuitry are merely exemplary and not intended to limit in any way. For example, the components described above do not necessarily require a single package. In some embodiments, controller 226 may be coupled to one or more wireless communication modules 228 (e.g., Bluetooth Low Energy radio modules, Zigbee modules) configured to facilitate the transmission and / or reception of signals. Communication module 228 may also be coupled to one or more antennas 230 and one or more power sources, such as battery 290. In some embodiments, the components described above may be partially or completely integrated into a single package (e.g., within an integrated circuit and / or system-on-a-chip).

[0025] In some embodiments, device 202 may be communicatively coupled to device 204, which may be a smartphone, tablet computer, laptop computer, auxiliary device communicating with another device, wearable host device, or other device separate from device 202. However, in other embodiments, a single device 202 may include, for example, Figure 2 The device 204 shown in the diagram has the following functions. The communication circuitry 232 in device 204 may optionally include circuitry for communicating with electronic devices (such as device 202), networks (such as the Internet, intranets, wired networks and / or wireless networks, cellular networks and wireless local area networks (LANs)). The communication circuitry 232 may also optionally include circuitry for using near-field communication (NFC) and / or short-range communication such as... The circuit used for communication.

[0026] Device 204 may optionally include various sensors 234 (e.g., hand tracking sensors, position sensors, image sensors, touch-sensitive surfaces, motion and / or orientation sensors, eye tracking sensors, microphones or other audio sensors, etc.), one or more display generation components (such as display 236), one or more processors 238, one or more memories 240, input devices 242 and other components. Figure 2 One or more communication buses, not shown, may optionally be used for communication between the components of device 204 mentioned above.

[0027] Processor 238 may optionally include one or more general-purpose processors, one or more graphics processors, and / or one or more digital signal processors (DSPs). In some embodiments, memory 240 may be a non-transitory computer-readable storage medium (e.g., flash memory, random access memory, or other volatile or non-volatile memory or storage device) storing computer-readable instructions configured to be executed by processor 238 to perform the techniques, processes, and / or methods described herein. In some embodiments, memory 240 may include a non-transitory computer-readable storage medium. A non-transitory computer-readable storage medium may be any medium (e.g., excluding signals) that can tangibly contain or store computer-executable instructions for use by or in connection with instruction execution systems, apparatuses, and devices. Non-transitory computer-readable storage media may include, but are not limited to, magnetic storage devices, optical storage devices, and / or semiconductor storage devices. Examples of such storage devices include magnetic disks, optical discs based on CD, DVD, or Blu-ray technology, and persistent solid-state memories such as flash memory, solid-state drives, etc.

[0028] Display 236 may optionally include a single display (e.g., a liquid crystal display (LCD), an organic light-emitting diode (OLED), or other types of display). In some embodiments, display 236 may include multiple displays. In some embodiments, display 236 may include a display having a touch-sensitive surface (e.g., a touchscreen), a projector, a holographic projector, a retinal projector, etc.

[0029] In some embodiments, sensor 234 may include a touch-sensitive surface configured to receive user input (touch and / or proximity input) such as tap and swipe inputs or other gestures. In some embodiments, display 236 and the touch-sensitive surface together may form a touch-sensitive display (e.g., a touchscreen integrated with or communicating with device 204 externally to device 204). Device 204 may also optionally include one or more input devices 242 other than the touch-sensitive surface, such as a physical keyboard, mouse, stylus and / or joystick (or any other suitable input device), and receive input from said one or more input devices.

[0030] Sensor 234 may also include image sensors, which may optionally include one or more visible light image sensors (such as charge-coupled device (CCD) sensors) and / or complementary metal-oxide-semiconductor (CMOS) sensors operable to obtain images of physical objects from the real-world environment. The image sensors may optionally include one or more infrared (IR) or near-infrared (NIR) sensors (such as passive or active IR or NIR sensors) for detecting infrared or near-infrared light from the real-world environment. For example, an active IR sensor may include an IR emitter for emitting infrared light into the real-world environment. The image sensors may optionally include one or more cameras configured to capture movement of the physical object in the real-world environment. The image sensors may optionally include one or more depth sensors configured to detect the distance between the physical object and device 204. In some embodiments, information from one or more depth sensors may allow the device to identify objects in the real-world environment and distinguish them from other objects in the real-world environment. In some embodiments, one or more depth sensors may allow the device to determine the texture and / or shape of objects in the real-world environment.

[0031] In some embodiments, device 204 may use a combination of a CCD sensor, an event camera, and a depth sensor to detect the physical environment surrounding the device. In some embodiments, the image sensor may include a first image sensor and a second image sensor. The first and second image sensors may work together and may optionally be configured to capture different information about physical objects in the real-world environment. In some embodiments, the first image sensor may be a visible light image sensor, and the second image sensor may be a depth sensor. In some embodiments, device 204 may use the image sensor to detect the position and orientation of device 204 and / or display 236 in the real-world environment. For example, device 204 may use the image sensor to track the position and orientation of display 236 relative to one or more stationary objects in the real-world environment. In some embodiments, sensors such as cameras (e.g., image sensors) may be used to capture images of the real-world environment. The images may be processed by processing circuitry (one or more processors 238) to locate and measure light sources. In some embodiments, light may be determined based on reflections from light sources in the environment and / or shadows cast by light sources in the environment. In some embodiments, deep learning (e.g., supervised learning) or other artificial intelligence or machine learning is used to estimate illumination characteristics based on the input image.

[0032] In some embodiments, sensor 234 may optionally include a hand-tracking sensor and / or an eye-tracking sensor. The hand-tracking sensor may be configured to track the position and / or movement of a user's hand and / or fingers relative to a computer-generated environment, relative to display 236, and / or relative to another coordinate system. An eye-tracking sensor (different from electrodes 208, which may also be used for eye tracking) may be configured to track the position and movement of a user's gaze (eyes, face, or head, more generally) relative to a real-world or computer-generated environment and / or relative to display 236. The user's gaze may include the direction in which the eyes are guided, optionally intersecting with a specific point or spatial region, and / or intersecting with a specific object. In some embodiments, the hand-tracking sensor and / or eye-tracking sensor may be implemented together with display 236 (e.g., in the same device). In some embodiments, the hand-tracking sensor and / or eye-tracking sensor may be implemented separately from display 236 (e.g., in different devices).

[0033] In some implementations, the hand-tracking sensor may use an image sensor (e.g., one or more IR cameras, 3D cameras, depth cameras, etc.) that captures three-dimensional information from the real world, including one or more hands. In some examples, the hand can be distinguished with sufficient resolution to differentiate the fingers and their corresponding positions. In some implementations, one or more image sensors may be positioned relative to the user to define the image sensor's field of view and interaction space, in which the finger / hand position, orientation, and / or movement captured by the image sensor are used as input (e.g., to differentiate from the user's idle hand or other hands of other people in the real-world environment). The advantage of tracking fingers / hands used for input (e.g., gestures) may be that using fingers / hands for input provides an input method that does not require the user to touch or hold the input device, and using an image sensor allows tracking without requiring the user to wear beacons or sensors on their hand / finger.

[0034] In some embodiments, the eye-tracking sensor may include one or more eye-tracking cameras (e.g., IR cameras) and / or an illumination source (e.g., an IR light source / LED) that emits light toward the user's eyes. The eye-tracking camera may be pointed at the user's eyes to receive reflected light from the light source directly or indirectly from the eyes. In some embodiments, both eyes are tracked separately by a corresponding eye-tracking camera and illumination source, and gaze can be determined by tracking both eyes. In some embodiments, one eye (e.g., the dominant eye) is tracked by a corresponding eye-tracking camera / illumination source.

[0035] Device 204 may optionally include a microphone or other audio sensor. Device 204 may use the microphone to detect sound from the user and / or the user's real-world environment. In some embodiments, the microphone may include an array of microphones that optionally operate together (e.g., to identify ambient noise or locate sound sources in the space of the real-world environment). In some embodiments, audio and / or voice input captured using one or more audio sensors (e.g., microphones) may be used to interact with a user interface or computer-generated environment when permitted by the user of the electronic device.

[0036] Device 204 may optionally include a position sensor configured to detect the position of device 204 and / or display 236. For example, the position sensor may optionally include a GPS receiver that receives data from one or more satellites and allows device 204 to determine its absolute position in the physical world. Device 204 may also optionally include a motion and / or orientation sensor configured to detect the orientation and / or movement of device 204 and / or display 236. For example, device 204 may use an orientation sensor to track changes in the position and / or orientation of device 204 and / or display 236 (e.g., relative to a physical object in a real-world environment). The orientation sensor may optionally include one or more gyroscopes, one or more accelerometers, and / or one or more inertial measurement units (IMUs).

[0037] Device 204 or system 200 may support a variety of applications that can be displayed in a computer-generated environment, such as one or more of the following applications: drawing applications, presentation applications, word processing applications, website creation applications, disk editing applications, spreadsheet applications, game applications, telephone applications, video conferencing applications, email applications, instant messaging applications, fitness support applications, photo management applications, digital camera applications, digital video camera applications, web browsing applications, digital music player applications, TV channel browsing applications, and / or digital video player applications.

[0038] A computer-generated environment can be displayed using one or both of devices 202 and 204 (including the use of one or more display generation components). The computer-generated environment may optionally include various graphical user interfaces (“GUIs”) and / or user interface objects. As described herein, a computer-generated environment including various GUIs can be displayed using device 202 or device 204, which includes one or more display generation components. The computer-generated environment may include one or more GUIs associated with an application. For example, the computer-generated environment may display menus or optional options to launch or display a user interface for an application running in the computer-generated environment. Similarly, the computer-generated environment may display menus or optional options to perform actions regarding an application running in the computer-generated environment.

[0039] It should be understood that Figure 2 The architecture is exemplary, but devices 202 and 204 are not limited to this. Figure 2 The components and configurations. For example, devices 202 and 204 may include fewer, additional, or other components in the same or different configurations.

[0040] Figure 3 Multiple electrodes 304 for detecting eye events are shown in locations around a user's face and head, according to an example of this disclosure. Although in Figure 3 Not shown, but in a representative example, electrodes 304 may be formed in, coupled to, or otherwise disposed on a structure (such as eyeglasses), and in other examples, may be formed in, coupled to, or otherwise disposed on the housing of different types of head-mounted devices, such as a pair of goggles, glasses, a face mask, a helmet, or a sun visor. In various examples, the structure or device may have a shape factor that allows the structure or device to rest partially or completely on the user's face. In some examples, the structure or device may include one or more transparent or nearly entirely transparent lenses 306. In some examples, lenses 306 may be formed of suitable materials selected to optimize durability, visibility, glare reduction, and / or projection or display of images / videos (e.g., to display user interfaces and corresponding elements). In some embodiments, one or more materials may be partially or completely disposed above the surface of one or more faces of lens 306 to achieve the aforementioned optical and / or mechanical properties.

[0041] In some embodiments, electrodes 304 may function as sensors configured to capture physiological signals associated with one or more eye events. For example, using electrodes 304 can provide a less costly implementation for performing eye tracking compared to camera-based systems. Electrodes 304 may have a linear or near-linear relationship between the eye's viewing angle and the amplitude of the output signal. By distributing multiple electrodes at different locations around the eye, electrodes 304 can extract information about the eye's orientation, movement, and / or fixation for further processing. In some embodiments, electrodes may be configured as electrooculography (EOG) sensors to provide measurements of the eye's electrical activity. Specifically, EOG sensors can detect the voltage difference between the cornea and retina of the eye and capture EOG signals. For example, EOG sensors may be configured to provide an indication of the dipoles formed between the cornea and retina of the eye. In addition to or alternatively, electrodes may be configured as electroencephalography (EEG) sensors that capture EEG signals and provide measurements of the user's brain's electrical activity. Alternatively, electrodes may be configured as electromyography (EMG) sensors to capture EMG signals and provide measurements of electrical activity in muscles and / or tissues associated with the eye. All these types of sensors can be used to capture and interpret the intentions of the wearer of device 300.

[0042] This document primarily describes implementations including sensors (e.g., referred to as EOG sensors) configured to detect EOG signals; however, it should be noted that this description is merely exemplary and not intended to be limiting in any way. For example, EEG signals, EMG signals, some combination thereof, and / or any suitable physiological electrical signals associated with one or more ocular events may be used in conjunction with and / or in place of one or more EOG sensors, where appropriate. Similarly, implementations describing EEG and / or EMG sensors may be supplemented with and / or replaced by EOG sensors, where appropriate.

[0043] In some embodiments, electrodes 304 may be placed on or within the housing of the structure or device, or some combination thereof. For example, electrodes 304 may be positioned such that when the structure or device is worn, substantial contact is made between the electrodes and one or more portions of the user's head, preferably with exposed skin. In various examples, electrodes 304a may be configured to contact the user's forehead, electrodes 304b and 304c may be configured to contact the opposite side of the user's nose, electrodes 304d and 304k may be configured to contact the ear and / or the area around the ear, electrodes 304e and 304f may be configured to contact the area around the user's temples, electrodes 304g and 304h may be configured to contact the area around the user's cheeks, and electrodes 304i and 304j may be configured to contact the area around the user's eyebrows.

[0044] In some embodiments, the number of electrodes 304 may be more and / or fewer than shown. For example, device 300 may include two electrodes that provide indication of one or more eye events to the device upon sensing. In addition, or alternatively, more than [a certain number of electrodes may be introduced]. Figure 3 The diagram shows a larger number of electrodes to provide additional information about eye movement.

[0045] It should be understood that the disclosure herein regarding the location, form, and function of the electrodes is not intended to be limiting in any way. In some embodiments, the electrodes may be arranged in different locations, on surfaces or in housings, and may present any suitable shape and / or size as needed. For example, the location of the electrodes may be selected based on the relative distance between the respective electrode and one or more (e.g., reference) electrodes. In some embodiments, the reference electrode may be arranged at a sufficient distance from one or more other electrodes (e.g., measuring electrodes) to increase the magnitude of the differential signal between the reference and the one or more electrodes. This may include electrode 304a, which provides a reference symmetrical with respect to additional electrodes (e.g., electrodes 304b and 304c may be arranged on opposite surfaces of the bridge of the nose, thus symmetrically arranged with respect to electrode 304a to achieve an EOG sensing configuration). In addition or alternatively, one or more reference electrodes may be dynamically selected when operating device 300 to configure an appropriate optical event sensing mode (e.g., EOG, EMG, and / or EEG). Alternatively or in addition, electrodes 304d and / or 304k (e.g., for EEG sensing) may be configured as reference electrodes, such that the reference electrodes are positioned sufficiently far from additional measurement electrodes (e.g., electrodes 304b and 304c) to increase the magnitude of the differential signal between the reference and either of the electrodes 304. For example, the first reference electrode may be connected to a first input of a differential amplifier, while the measurement electrode is connected to a second input of the differential amplifier. Simultaneously, the second reference electrode may be connected to a stimulation signal. The stimulation may be selected to mitigate the effects of undesirable common-mode noise on the differential signal between the first reference electrode and the measurement electrode due to mismatches between internal and external components in the signal path. Alternatively or in addition, the stimulation may be selected to otherwise mitigate the effects of undesirable noise on the sensing and operating device. In some embodiments, driving the second reference electrode (e.g., using right-leg driving technology) may improve the suppression of common-mode noise. For example, device 300 can sense ambient noise at 60 Hz, and a controller included in device 300 may include circuitry configured to drive a second reference electrode having a stimulus associated with reducing 60 Hz noise. In some embodiments, the reference electrode may be configured to cancel one or more signals (broadband noise, narrowband signals, etc.). It should be understood that any electrode can be configured to act as a reference electrode. For example, in some embodiments, a multiplexer may receive inputs from some or all of the electrodes and programmably select any one of the received inputs as the reference electrode. In some embodiments, the reference electrode may alternate between different electrode positions, and a set of electrode measurements may be obtained each time the reference electrode changes to a different position. These multiple sets of electrode measurements may be used in combination or individually to optimize signal quality and accuracy and to obtain data for eye gaze determination.

[0046] In some embodiments, electrode 304 may be a “dry” electrode (e.g., without conductive gel), which provides a discreet, low-cost, and practical solution for sensing EOG signals. Conventional wet electrodes utilize one or more materials configured to improve the detection of physiological signals; however, materials (e.g., electrolytic gels) may be uncomfortable and unsuitable outside of clinical applications, and may be more expensive than dry electrodes. Therefore, when implemented in some devices, electrode 304 may be formed from one material or a suitable combination of materials to ensure portability, reusability, cleanliness, and comfort while reducing costs. In some embodiments, electrode 304 may be formed from one or more suitable conductive materials (such as steel, copper, carbon, aluminum, copper, gold, silver, tin, beeswax, and / or titanium). The electrode may also include a coating (e.g., foam, powder, film, etc.) disposed on one or more surfaces of the electrode. The materials associated with the electrode may be suitably selected to optimize signal quality and impedance between the skin and the electrode.

[0047] When sensing EOG signals or other physiological signals, sufficient contact between the electrodes and the user's tissue (e.g., epidermis) can be crucial for improving signal quality and integrity, as well as obtaining predictable impedance presented to the device's driving and / or sensing circuitry. However, contact requirements can present challenges when designing devices that accommodate variations in the user's physical and physiological characteristics and user-induced movement (e.g., intentional or unintentional device displacement). For example, the human head provides a highly variable contact surface, including contours and variable surface conditions (including hair, oil, scar tissue, sweat, etc.). Furthermore, the user's head is frequently in motion and can cause device movement, potentially affecting electrode contact integrity. Therefore, wearable device solutions, particularly for eye gaze and / or detection applications, benefit from mechanisms that apply variable pressure between the electrodes and human tissue.

[0048] Therefore, in some embodiments, the electrodes may be coupled to elements configured to improve contact between the electrodes and the user's tissue. In some embodiments, these elements may apply pressure to the electrodes to press, pull, and / or deform them, thereby providing contact force on one or more surfaces of the electrodes before, during, and / or after electrical measurements. The applied force can better couple the user's tissue (e.g., epidermis) and the electrodes mechanically and electrically, thereby optimizing electrical measurements. In some embodiments, the contact force may be applied via mechanical elements.

[0049] Figure 4An exemplary electrode configuration according to an example of this disclosure is shown, which includes a spring-loaded needle element to improve coupling between the electrode and tissue. In some embodiments, device 400 may be configured to measure one or more EOG signals. As described above, it may be advantageous to provide continuous contact between electrode 404 and tissue 414, such that device 400 can reliably obtain measurements of electrical impulses associated with the user of the device, for example, by providing stimulation and / or measurement signals via the electrode. In some embodiments, the device may include one or more elements, such as spring-loaded needle 410, which may be coupled to the electrode to improve contact between one or more surfaces of the electrode and the tissue. In some embodiments, spring-loaded needle 410 and / or electrode 404 may be held within a housing 412 within the device and spring-biased relative to the housing. In some embodiments, tissue 414 may correspond to the user's skin (e.g., epidermis) of the electrode. In some embodiments, electrode 404 may be partially or completely mounted on a surface of the device. When tissue contacts the electrode, the spring-loaded needle may be compressed, thereby applying force toward the tissue to the electrode and improving the quality of mechanical and / or electrical contact.

[0050] Figure 5A An exemplary electrode configuration according to an example of this disclosure is shown, which includes one or more elements in an inactive state, but which may be activated to improve the coupling between electrode 504 and tissue 514. Figure 5A An exemplary device 500 is shown, comprising a housing 508, two electrodes 504A and 504B formed in or on the housing (although other electrodes may also be present in or on the device), and one or more elastomeric (elastic polymer) materials 516 (e.g., dielectric elastomer materials). In some examples, the elastomer 516 may be sandwiched between electrodes 504A and 504B. In some examples, the device 500 may include circuitry 518 for driving electrodes 504A and 504B. Driving electrodes 504B may change the shape of the elastomer 516 and conform the electrode to and contact the user's tissue 514 (e.g., epidermis). Although in Figure 5ANot shown, but electrodes 504 and elastomer 516 can also be arranged in other suitable configurations. For example, electrodes 504A and 504B can be arranged spaced apart in the same or nearly identical plane. Elastomer 516 can be arranged in a different plane from the electrodes, such that an electric field (e.g., formed by different voltages applied to electrodes 504A and 504B) can change the shape of the elastomer, and in some cases even when a portion of the surface of the elastomer is not coupled relative to a portion of the electrode. In some embodiments, elastomer 516 can be formed of an electroactive material including, but not limited to, dielectric elastomers. Dielectric elastomers can provide compressive stress in response to an applied electric field and can provide many benefits in EOG sensing systems, especially when incorporated into designs requiring robust, lightweight, and comfortable solutions. Dielectric elastomers can exhibit high flexibility / deformation in the presence of an applied electric field, but can return to their initial shape in the absence or reduction of the electric field. Dielectric elastomers may include acrylic resins, silicones, polyurethanes, fluoroelastomers, ethylene-propylene rubbers, and / or any other suitable materials capable of undergoing large reversible deformation in response to an electric field. As mentioned herein, dielectric elastomers will be used to describe a range of suitable electroactive materials; however, it should be understood that such descriptions and embodiments herein are merely exemplary and not intended to be limiting in any way.

[0051] Figure 5B Examples according to this disclosure are shown. Figure 5A An exemplary electrode configuration includes one or more elements in an activated state to improve coupling between electrode 504 and tissue 514. Figure 5B In this circuit, circuit 518 (e.g., a source) applies a voltage or current to electrodes 504A and 504B. In response to the application of voltage and / or current, an electric field is generated between electrodes 504A and 504B. In response to this applied electric field, the resulting electrostatic pressure and mechanical compression cause the elastic body 516 located between electrodes 504A and 504B to deform (compared to its state before deformation). Figure 5AIn contrast, the elastomer contracts in thickness and expands in area. Because electrodes 504A and 504B are coupled to the elastomer 516, the increased surface area of ​​the elastomer causes the electrodes to twist or “bend” and protrude from the device housing 508, resulting in an increased force or pressure exerted by the electrodes on the tissue 514. In some embodiments, the elastomer 516 is configured as a planar or near-planar membrane that may protrude beyond a dimension parallel to the plane of the membrane. In some embodiments, the elastomer 516 may be implemented as a multilayer dielectric elastomer material. Multilayer dielectric elastomers allow for the formation of complex shapes that conform to allow for better contact between the electrodes and the tissue and / or increase the contact surface area between the electrodes and the tissue. The number of layers will depend on the location of the electrodes around the area of ​​the face, where there is considerable variability among users (e.g., cheekbones, eyebrows, etc.).

[0052] Figure 6A An exemplary electrode configuration according to an example of this disclosure is shown, which includes one or more elements in an inactive state, but which may be activated to improve coupling between electrode 604 and tissue 614. In addition, the exemplary electrode configuration includes a pressure sensor 622 co-located with the electrode. Besides the addition of the pressure sensor 622 and associated electronics, Figure 6A Similar to Figure 5A and Figure 5B In some embodiments, each electrode pair of device 600 may be coupled to one or more corresponding pressure sensors 622. The pressure sensors 622 may be coupled to a surface and / or integrated into electrodes 604A and / or 604B, and may supply signals and / or data to controller 620 associated with the force exerted by the electrodes on tissue 614. In some embodiments, each electrode of device 600 may be coupled to one or more corresponding pressure sensors (e.g., an electrode or electrode grid). Therefore, wearable devices, such as headbands including one or more pressure sensors, can moderate the pressure exerted by electrodes 604 and balance the need to establish and maintain contact between the electrodes and tissue 614 (on the one hand) with user comfort (on the other hand).

[0053] Figure 6B Examples according to this disclosure are shown. Figure 6A An exemplary electrode and pressure sensor configuration is provided, which is activated to improve coupling between electrode 604 and tissue 614. Figure 6BIn the example, a circuit (e.g., a source) within controller 620 applies a voltage or current to electrodes 604A and 604B. In response to the application of voltage and / or current, an electric field is generated between electrodes 604A and 604B. In response to this applied electric field, the resulting electrostatic pressure and mechanical compression cause the elastic body 616 located between electrodes 604A and 604B to deform (compared to its state before deformation). Figure 6A In contrast, the elastomer shrinks in thickness and expands in area. Because electrodes 604A and 604B are coupled to the elastomer 616, the increased surface area of ​​the elastomer causes the electrodes to twist or “bend” and protrude from the device housing 608. Electrodes 604 and / or the elastomer 616 come into contact with tissue 614, which may correspond to the user's tissue, such as the epidermis.

[0054] Because pressure sensor 622 is co-located with electrode 604, the pressure sensor can detect the pressure applied to the tissue by the electrode when the electrode contacts tissue 614. Device 600 may include control circuitry within controller 620 coupled to pressure sensor 622 to capture and process pressure readings from the pressure sensor. In some examples, pressure sensor 622 may be monitored selectively rather than continuously. For example, nose / ear electrodes may detect the presence of brain signals or other signals indicating user activity (e.g., by detecting EEG and / or EOG signals). When user activity is detected, other electrodes (e.g., around the eye area) may be activated, and the pressure sensor circuitry may also be activated. When pressure sensing is activated, pressure sensor 622 may supply the controller 620 with signals and / or data associated with the force applied to tissue 614 by electrode 604. In some embodiments, each electrode of device 600 may be coupled to one or more corresponding pressure sensors (e.g., an electrode or electrode grid).

[0055] Figure 6C A feedback control system 648 for adjusting the amount of pressure applied by electrode 604 to tissue 614, according to some examples of this disclosure, is shown. The feedback control system 648 ensures that electrode 604 applies sufficient pressure to tissue 614 to obtain an accurate electrode signal, while maintaining a relative limit on the applied pressure to ensure that the user is not subjected to excessive mechanical force when the device attempts to optimize contact. In some embodiments, relevant pressure sensor data may be used as part of a closed-loop feedback control system 648 associated with device 600. The feedback control system 648 may include a pressure sensor 622, a comparator 652, drive circuitry 654, and an elastomer 616. Figure 6BIn one embodiment, the actual pressure 660 applied between the electrode 604 and the tissue 614 can be detected by a pressure sensor 622. The pressure signal 650 from the pressure sensor 622 can be fed back to a comparator 652, which determines the difference between the desired pressure P0 and the actual pressure 660 and generates a difference signal 656. The desired pressure P0 can be a predetermined pressure level intended to provide sufficient electrode signal quality for accurate eye-tracking. The difference signal 656 can be fed into a drive circuit 654, which generates a voltage signal 658 to the electrodes 604, which in turn can cause changes in the deformation of the elastomer 616 and the actual pressure 660. If the difference signal 656 indicates that the actual pressure 660 is less than the desired pressure P0, the drive circuit 654 can modify the voltage signal 658 applied to the electrode 604 to further bend or deform the elastomer 616 and increase the actual pressure 660. After one or more iterations, the feedback control system 648 may increase the actual pressure 660 until it reaches an achieved pressure P that is approximately equal to the desired pressure P0. However, if the difference signal 656 indicates that the actual pressure 660 is greater than the desired pressure P0, the drive circuit 654 may modify the voltage signal 658 applied to the electrode 604 to reduce the bending or deformation of the elastomer 616 and reduce the actual pressure 660 until it reaches the desired pressure P0. The feedback control system 648 also ensures that the actual pressure 660 is not large enough to subject the user to excessive mechanical force when the device attempts to optimize contact. In some embodiments, the control algorithm associated with the closed-loop feedback system may run locally. Alternatively, the control algorithm may be run partially or entirely by a device communicatively coupled to the device 600 (e.g., using a wireless communication channel). In addition or alternatively, pressure data may be monitored and / or replaced by other characteristics associated with EOG sensing, including but not limited to the impedance of one or more portions of the sensing circuit, the signal-to-noise ratio of the received signal, and data associated with the movement of the device and / or its constituent parts.

[0056] For example, instead of pressure sensor 622, the impedance of the contact between electrode 604 and skin / tissue 614 can be estimated, and the current (e.g., a current signal) applied to elastomer 616 (dielectric polymer) can be varied as needed until sufficient impedance is achieved. Impedance measurements can be obtained via circuitry also used for connection to the electrodes. For example, device 600 may include one or more current sources configured to supply current to the user's body. The voltage and current measured via electrode 604 can be used to calculate the impedance associated with sensing the EOG signal. Specifically, impedance can indicate the quality of contact between tissue 614 and electrode 604.

[0057] When sufficient electrode contact is made with the user's tissue to generate an accurate electrode signal, electrode data can be collected and processed to perform gaze detection and eye tracking. Gaze detection and eye tracking can be used as user input to trigger various functions. In addition to or alternatively, other triggers for switching between operating modes can be implemented. For example, triggers may involve eye events including detecting the user's gaze. Specifically, eye events may include a predefined area of ​​gaze, including but not limited to a corner of the user's field of vision (referred to herein as the "trigger angle"). The trigger angle may also be configured based on the absolute and / or relative dimensions of the device. To accommodate differences in the physical characteristics of potential users, for example, the trigger angle may correspond to detecting gaze at a location on or within the lens (e.g., corresponding to...). Figure 3 (The corner of lens 306). Alternatively, the trigger angle can be determined partly or entirely based on the determination of the relative angle of the user's eyes. In some embodiments, a first eye event (e.g., directing the gaze toward the trigger angle) can be detected at a first resolution, and one or more additional eye events can be detected at a higher resolution after the eye event is detected (e.g., after a threshold amount of time). This embodiment allows the system to capture a wide range of general eye events and, in response to a condition (e.g., a threshold amount of time, a sequence of one or more gazes at one or more locations, and / or the detection of one or more blinks), capture finer and more accurate variations associated with one or more eye events.

[0058] In some embodiments, multiple electrodes may be configured to detect EOG signals, signals associated with eye movement that can be mapped to a defined coordinate system. In some embodiments, the electrodes may be configured to generate a two-dimensional coordinate map to interpret eye movement. In some examples, the two-dimensional coordinate map may involve eye rotation (e.g., toward the coronal plane bisects the user's head). For example, a user's straight-ahead gaze may correspond to an initial position, such as a vector extending orthogonally (e.g., in the Z direction) to an imaginary coronal plane bisects the user's head (e.g., an XY two-dimensional plane). In some embodiments, the electrodes may provide a linear or approximately linear relationship between eye rotation (e.g., vertical and horizontal rotation or a combination thereof) and the voltage output by the electrodes. Thus, an exemplary device may detect one or more voltages from the electrodes and compute the perceived rotation of the eye as a processed signal (e.g., a signal indicating vertical and horizontal rotation or a combination thereof). In some embodiments, one or more processed signals may be used to compute the rotation of the eye away from the initial position, and a vector corresponding to the eye movement may be computed. In some examples, vectors can be projected onto an imaginary coronal plane to better correlate the vertical and / or horizontal movement of the eye with the vertical and / or horizontal navigation of the user interface.

[0059] An exemplary use case for the behavior described above could be unlocking a user's device 600 in response to an eye event. Unlocking device 600 could include providing the user with access to one or more functions and / or operating modes of the device. For example, even when mounted on the user's head, device 600 could remain in a low-power mode until an eye event is detected.

[0060] In response to the detection that device 600 is worn by a user, the device may optionally activate the functionality of one or more components to improve the detection of eye events, but the device state may appear almost completely or completely unchanged to the user. In this operating mode, device functionality may be partially enabled. After optionally entering a more fully enabled mode, the user may optionally be prompted to guide their gaze toward a position. In some embodiments, the user's gaze and / or movement may correspond to eye events including eye movement from a first direction to a second direction (e.g., eye movement from the left side of the screen to the right side of the screen). It should be understood that the described eye events are not limiting and may correspond to any suitable movement, including but not limited to linear or almost perfectly linear (e.g., vertical, horizontal, diagonal) eye movement or eye movement along curved and / or irregular paths.

[0061] In some embodiments, device 600 may be configured to detect eye events using a minimal number of electrodes (e.g., two electrodes). For example, device 600 may include two electrodes configured to detect one or more eye events. In some embodiments, as few as two electrodes may be implemented to detect wake-up conditions. The wake-up conditions described herein can be combined in a variety of combinations. As described herein, wake-up conditions may include detecting EOG and / or EEG signals corresponding to a user placing device 600 on their head. Wake-up conditions may also, in addition to or alternatively, include detecting directional eye movements, such as unidirectional eye movements. In some embodiments, wake-up conditions may include eye events associated with a user's gaze at a trigger angle. For example, a device including at least three electrodes may be configured to detect eye events corresponding to a gaze at a specific angle of the eye, thereby providing device 600 with EOG sensor data that may optionally be used as a wake-up condition.

[0062] Figure 7 Exemplary signal processing of electrode signals according to some embodiments of the present disclosure is illustrated. In some embodiments, electrode signal 766 may correspond to a direct measurement value of the electrode. The voltage corresponding to electrode signal 766 may be further processed by a head-mounted device (such as in...). Figure 2 (in the AFE 224 of device 202), and / or further processed by an associated computing system that may optionally be a separate device (such as in Figure 2(In device 204). For example, the signal may pass through one or more filters. In some embodiments, the filters may include one or more high-pass filters 762, one or more band-pass filters (not shown), and / or one or more low-pass filters 764. Filters may be configured to attenuate noise, mitigate signal drift, prevent aliasing, etc. One or more machine learning algorithms may be configured, in addition to or alternatively, to process the received electrode signal 766. For example, a convolutional neural network (CNN)-based model 768 may be applied to the data corresponding to the electrode signal 766 to improve the characteristics of horizontal angle and / or viewing angle, blink events, and / or gaze fixation, and generate an updated model 770. The device and / or associated computing system may be configured to invoke functions, methods, and / or processes associated with the device and / or system, including switching between operating modes, activating speech recognition software, etc.

[0063] Figure 8 Exemplary electrodes 804 and analog front-end 872 for processing electrode signals are shown according to some embodiments of this disclosure. Active electrode 804-A and reference electrode 804-B are available. Figure 8 The exemplary circuit elements shown are used for modeling. In some examples, these electrodes 804 may have a signal amplitude of 50µV to 3.5mV, a frequency content of 0Hz to 40Hz, and an electrode DC offset of up to + / -1V (which may depend on the electrode material and skin contact). In some embodiments, the device may include an analog front end 872 to condition and sample the signals from these electrodes. For example, the device circuitry may include one or more amplifiers 874 (e.g., programmable gain amplifiers). The inputs of the respective amplifiers may be connected to, for example,... Figure 8 The active and reference electrodes shown are used to obtain a differential voltage at the amplifier output, which corresponds to the relative voltage difference detected by the active electrodes and associated with an eye event. The output of amplifier 874 may be further coupled to one or more variable analog-to-digital converters (ADCs) 876, which may be configured to quantize the signal at one or more resolutions. Controller 878 may be coupled to one or more ADCs 876 to receive and / or process the digitized signal.

[0064] In some embodiments, the analog front end 872 may include one or more elements for measuring impedance. For example, the analog front end may include one or more current sources configured to stimulate a user's tissue. The voltage measured in response (e.g., by one or more electrodes of the device) can then be used with a known current to calculate the impedance. In some embodiments, the measured impedance may be used by a controller included in the device to configure one or more dielectric elastomers (e.g., to increase and / or decrease the pressure between one or more electrodes and the user's tissue). Increased pressure helps achieve better signal quality by reducing the electrode-skin impedance to a level that does not impair user comfort.

[0065] In some implementations, the analog front-end circuitry may be configured to specific specifications. For example, the signal received by the one or more amplifiers may span a range including, but not limited to, 50µV to 3.5mV, thus including frequency content including, but not limited to, 0Hz to 40Hz. Additionally or alternatively, the common-mode input range of the amplifier may include + / -1V, and the input impedance may exceed 1GΩ.

[0066] Figure 9 Examples of EOG sensor data associated with a head-mounted device according to some examples of this disclosure are shown. In some embodiments, the device may include multiple electrodes configured to detect eye movement. In some embodiments, the electrodes may be arranged to capture EOG signals. As described herein, the electrode configuration is not limited in any way, provided that the signals captured by the electrodes are associated with eye events. For example, the EOG signal output by the electrodes may correspond to a user's blink. In addition or alternatively, the intensity of the blink may be sensed and detected by the head-mounted device. In some embodiments, one or more electrodes may be arranged to contact tissue above and / or below the user's eyes. In addition or alternatively, one or more electrodes may be arranged to contact tissue on the outer and / or inner sides of the eyes. In some embodiments, the electrodes may be arranged to contact the bridge of the user's nose (e.g., corresponding to...). Figure 3 The electrodes 304b and / or 304c are in contact with the user's forehead (e.g., corresponding to electrode 304a) and / or with the area around and behind the user's ears (e.g., corresponding to 304d and 304k).

[0067] In some implementations, the electrode in contact with the user's forehead may be configured as a reference voltage to calculate multiple differential voltages indicating eye gaze and / or movement. For example, signals 932 and 934 may correspond to the differential voltage between the reference electrode on the user's forehead (e.g., corresponding to electrode 304a) and electrodes on the right and left sides of the user's nose (e.g., corresponding to electrodes 304b and 304c). Signals 936 and 938 may correspond to the differential voltage between the reference electrode and electrodes behind / around the user's right and left ears (e.g., corresponding to electrodes 304d and 304k).

[0068] In some implementation schemes, Figure 9 The signals shown may correspond to several eye events. For example, signals 932, 934, 936, and 938 during time period 940 may correspond to a user's blink. As previously mentioned, the intensity of the blink may also be detected. Blinking can be used to perform functions of the device, such as confirming and / or selecting elements of the user interface associated with the head-mounted device. In some embodiments, the EOG signals provided by the electrodes may correspond to eye rotation in one or more directions. For example, events associated with eye movement may correspond to the horizontal and / or vertical angles of the gaze and may be detected during time period 942. During time period 942, signals 932, 934, 936, and 938 exhibit a descending slope that may correspond to changes in the eye's viewing angle, including an upward shift of the user's gaze. In some embodiments, the EOG signals may also capture the state of the user's gaze. Time period 944 may correspond to the user maintaining a specific viewing angle (e.g., the viewing angle established during time period 942). In addition, subsequent changes in the viewing angle may be detected, as shown during time period 946, which may correspond to a rightward shift of the user's gaze. In some implementations, the settling or near-settling periods of signals 932, 934, 936, and 938 may increase and / or decrease as the user's gaze angle changes. Similarly, in some implementations, the magnitudes of signals 932, 934, 936, and 938 may vary from user to user and vary with the intensity of the event (e.g., based on the intensity of a blink).

[0069] Figure 10Methods for reducing power consumption in eye tracking according to some examples of this disclosure are illustrated. Device power consumption can be particularly critical when integrated power is limited (e.g., in wearable devices that include a limited power source, such as a battery). Furthermore, heat generated during operation of the electronics can increase discomfort with the wearable device; therefore, reducing the power consumed by the device can be a critical device and / or system design consideration. In some embodiments, signals captured by electrodes with sufficient contact can be captured and configured to alter the operating mode of the device. As described above, electrodes can be arranged and configured to contact one or more of the temples, nose, cheeks, eyebrows, behind the ears, etc. In some embodiments, a subset of the device's electrodes (e.g., electrodes in contact with the user's nose and / or one or more ears) can be configured to capture signals corresponding to the user's brain activity. For example, electrical impulses corresponding to eye and / or muscle movements within the user's face can be detected. In addition, or alternatively, brain activity associated with eye and / or muscle movements can be detected. In some embodiments, the device may operate in a low-power mode, as shown in box 1080, before brain activity is sensed (e.g., an EEG signal is detected). The low-power mode may include shutting down some or all of the components and / or circuitry within and / or associated with the head-mounted device. In some embodiments, some or all of the components and / or circuitry may be configured to be in a sleep mode (e.g., low power consumption). In some embodiments, the low-power mode may include configuring some or all of the components and / or circuitry associated with the head-mounted device to operate polling registers, communication channels, or other computing and sensing circuitry at a lower rate and / or resolution. In some embodiments, the device may operate in a low-power mode until further electrical activity associated with one or more eye events is detected, and the detected electrical activity may be quantified into energy levels (e.g., by integrating the electrical activity over time), as shown in box 1082. When operating in low-power mode, power is conserved before a trigger is received (e.g., detection of brain activity and / or eye events), thereby optimizing device lifespan and minimizing excessive computation, calculation, and / or measurement beyond those associated with the detection of a trigger. In some embodiments, the calculated energy level can be compared to a threshold energy level, as shown in box 1082. If the calculated energy level exceeds the threshold, this can trigger the device to enter a higher-power mode.

[0070] Upon detection of a trigger, the operating mode can transition from a lower power mode to a higher power mode, as shown in box 1084. For example, one or more analog-to-digital converters (ADCs) can be configured to transition from a first resolution (box 1080) under lower power conditions to a second resolution (box 1084) under higher power conditions, the second resolution being finer than the first resolution. In some examples, the trigger may also be associated with stimulation, measurement, and / or configuration of one or more electrodes enabling the device. In some embodiments, in response to a trigger, one or more electrodes can transition from a sleep (i.e., lower power) mode to a higher power mode, in which the one or more electrodes can be sensed, polled, and / or detected. Additionally or alternatively, a pressure sensor 622 coupled to and / or embedded in the electrodes can be similarly configured in response to a trigger. In some embodiments, coarse electrode-based eye tracking, as shown in box 1086, can be utilized until a finer resolution eye tracking is required, which may depend on the functions performed by the eye tracking and / or the presented application or user interface. Where a finer resolution eye tracking is required, camera-based eye tracking can be utilized, as shown in box 1088.

[0071] Therefore, based on the foregoing, some examples of this disclosure relate to a device for detecting eye movement, the device comprising: a sensing circuit configured to sense physiological signals, the sensing circuit including a plurality of electrodes; and one or more elastomeric materials coupled to corresponding electrode pairs among the plurality of electrodes, wherein the corresponding electrode pairs are configured to receive signals associated with a change in the shape of the one or more elastomeric materials, and the corresponding electrode pairs are configured to improve contact between at least one electrode in the corresponding electrode pair and a user's tissue. Alternatively, or in addition to one or more of the examples above, in some examples, the one or more elastomeric materials comprise dielectric elastomeric materials. Alternatively, or in addition to one or more of the examples above, in some examples, the device further comprises: one or more pressure sensors coupled to at least one electrode in the corresponding electrode pair; and control circuitry coupled to the one or more pressure sensors and the sensing circuitry. Alternatively, or in addition to one or more of the examples above, in some examples, the signals associated with a change in the shape of the one or more elastomeric materials are modified based on a first criterion. Alternatively, or in addition to one or more of the examples above, in some examples, the first criterion includes satisfying a threshold signal-to-noise ratio associated with a physiological signal. Alternatively, or in addition to one or more of the examples above, in some examples, the first criterion includes a threshold amount of force detected by the one or more pressure sensors. Alternatively, or in addition to one or more of the examples above, in some examples, the signal associated with changing the shape of one or more elastomeric materials is modified based on impedance associated with a physiological signal. Alternatively, or in addition to one or more of the examples above, in some examples, the device further includes one or more current sources configured to supply current to corresponding electrode pairs via the user's tissue. Alternatively, or in addition to one or more of the examples above, in some examples, the physiological signal is a differential signal between two corresponding electrode pairs of the plurality of electrodes, wherein a first corresponding electrode pair of the plurality of electrodes is configured as a reference electrode, and a second corresponding electrode pair of the plurality of electrodes is configured as an active electrode. Alternatively, or in addition to one or more of the examples above, in some examples, the device further includes: circuitry configured to detect noise affecting the device; and a third corresponding electrode of the plurality of electrodes configured to supply a stimulation signal to the user of the device, wherein the stimulation signal is associated with reducing the detected noise.Alternatively, or in addition to one or more of the examples above, in some examples, the device further includes: one or more amplifiers coupled to respective electrode pairs; one or more analog-to-digital converters, wherein the resolution of each of the one or more analog-to-digital converters is variable; and communication circuitry communicatively coupled to the processing circuitry and configured to transmit data associated with physiological signals. Alternatively, or in addition to one or more of the examples above, in some examples, the physiological signals are associated with one or more eye events. Alternatively, or in addition to one or more of the examples above, in some examples, the plurality of electrodes includes one or more electrooculography (EOG) sensors.

[0072] Some examples of this disclosure relate to a method for detecting eye movement, the method comprising: coupling one or more elastomeric materials to a respective electrode pair of a plurality of electrode pairs; contacting the respective electrode pair and the one or more elastomeric materials with tissue associated with a user's eye; receiving a signal at the respective electrode pair; modifying the shape of the one or more elastomeric materials and the coupled respective electrode pair based on the received signal to improve contact between the respective electrode pair and the user's tissue; and sensing a physiological signal from the respective electrode pair, the physiological signal being associated with eye movement. Alternatively, or in addition to one or more of the examples above, in some examples, the one or more elastomeric materials comprise a dielectric elastomeric material. Alternatively, or in addition to one or more of the examples above, in some examples, the method further comprises modifying the shape of the one or more elastomeric materials and the coupled respective electrode pair based on a first criterion. Alternatively, or in addition to one or more of the examples above, in some examples, the first criterion comprises the amount of force exerted by the respective electrode pair on the user's tissue. Alternatively, or in addition to one or more of the examples above, in some examples, the first criterion comprises a threshold signal-to-noise ratio associated with the physiological signal. Alternatively, or in addition to one or more of the examples above, in some examples, the first criterion includes a threshold impedance associated with a physiological signal. Alternatively, or in addition to one or more of the examples above, in some examples, the corresponding electrode pair includes one or more electrooculography (EOG) sensors.

[0073] Some examples of this disclosure relate to a device for detecting eye movement, the device comprising: a sensing circuit configured to sense physiological signals associated with eye movement from a plurality of electrodes; and a processor communicatively coupled to the sensing circuit and programmed to: operate the sensing circuit in a first power level operating mode based on the physiological signal satisfying a first criterion indicating a first level of eye movement; and operate the sensing circuit in a second power level operating mode, different from the first mode, based on the physiological signal satisfying a second criterion indicating a second level of eye movement. Alternatively, or in addition to one or more of the examples above, in some examples, the first power mode includes operating one or more analog-to-digital converters at a first resolution, and the second power mode includes operating the one or more analog-to-digital converters at a second resolution higher than the first resolution. Alternatively, or in addition to one or more of the examples above, in some examples, the first criterion includes comparing the energy level of the physiological signal with the energy of a threshold amount. Alternatively, or in addition to one or more of the examples above, in some examples, the first criterion is associated with blinking. Alternatively, or in addition to one or more of the examples above, in some examples, the first criterion is associated with eye fixation. Alternatively, or in addition to one or more of the examples above, in some examples, the first criterion includes determining via sensing circuitry that a user of the device is wearing the device. Alternatively, or in addition to one or more of the examples above, in some examples, the physiological signal includes an electrooculogram (EOG) signal. Alternatively, or in addition to one or more of the examples above, in some examples, the processor is further programmed to operate the sensing circuitry and processing circuitry in a third operating mode, different from the first and second modes, when the sensing circuitry is operated in a second power level operating mode, based on the physiological signal satisfying a third criterion. Alternatively, or in addition to one or more of the examples above, in some examples, the device also includes one or more cameras configured to detect eye events, and operation in the third operating mode also includes using the one or more cameras to collect information associated with the physiological signal.

[0074] Some examples of this disclosure relate to a method for detecting eye movement, the method comprising: sensing a physiological signal from a plurality of electrodes, the physiological signal being associated with eye movement; operating a sensing circuit in a first power level operating mode based on the physiological signal satisfying a first criterion indicating a first level of eye movement; and operating the sensing circuit in a second power level operating mode, different from the first mode, based on the physiological signal satisfying a second criterion indicating a second level of eye movement. Alternatively, or in addition to one or more of the examples above, in some examples, the first power mode includes operating one or more analog-to-digital converters at a first resolution, and the second power mode includes operating the one or more analog-to-digital converters at a second resolution higher than the first resolution. Alternatively, or in addition to one or more of the examples above, in some examples, the first criterion includes comparing the energy level of the physiological signal with the energy of a threshold amount. Alternatively, or in addition to one or more of the examples above, in some examples, the first criterion is associated with blinking. Alternatively, or in addition to one or more of the examples above, in some examples, the first criterion is associated with eye fixation. Alternatively, or in addition to one or more of the examples above, in some examples, the first criterion includes determining that a user of the device is wearing the device. Alternatively, or in addition to one or more of the examples above, in some examples, the physiological signals include electrooculography (EOG) signals or electroencephalography (EEG) signals. Alternatively, or in addition to one or more of the examples above, in some examples, the method further includes: when the sensing circuit is operated in a second power level operating mode, operating the sensing circuit and processing circuit in a third operating mode, different from the first and second modes, based on the physiological signals meeting a third criterion. Alternatively, or in addition to one or more of the examples above, in some examples, operating in the third operating mode further includes using one or more cameras to collect information associated with the physiological signals.

[0075] While examples of this disclosure have been fully described with reference to the accompanying drawings, it should be noted that various changes and modifications will become apparent to those skilled in the art. It should be understood that such changes and modifications are considered to be included within the scope of the examples of this disclosure as defined by the appended claims.

Claims

1. A device for detecting eye movement, the device comprising: A sensing circuit configured to sense physiological signals, the sensing circuit including a plurality of electrodes; and One or more elastomeric materials, said one or more elastomeric materials being coupled to corresponding electrode pairs among the plurality of electrodes; The respective electrode pair is configured to receive physiological signals, and the shape of the respective electrode pair and the shape of the one or more elastomeric materials are changed based on the received physiological signals to improve contact between at least one electrode of the respective electrode pair and the user's tissue.

2. The device according to claim 1, wherein the one or more elastomeric materials include dielectric elastomer materials.

3. The device according to claim 1, further comprising: One or more pressure sensors, the one or more pressure sensors being coupled to at least one electrode in the respective electrode pair; and A control circuit, which is coupled to the one or more pressure sensors and the sensing circuit.

4. The device of claim 3, wherein the signal associated with modifying and changing the shape of the one or more elastomeric materials is based on a first criterion.

5. The device of claim 4, wherein the first criterion includes satisfying a threshold signal-to-noise ratio associated with the physiological signal.

6. The device of claim 4, wherein the first criterion includes a threshold amount of force detected by the one or more pressure sensors.

7. The device of claim 1, wherein the signal associated with changing the shape of the one or more elastomeric materials is modified based on impedance associated with the physiological signal.

8. The device of claim 7, further comprising one or more current sources configured to supply current to the respective electrode pairs via the tissue of a user of the device.

9. The device according to claim 1, wherein the physiological signal is a differential signal between two corresponding electrode pairs of the plurality of electrodes, wherein: The first corresponding electrode pair among the plurality of electrodes is configured as a reference electrode, and The second corresponding electrode pair among the plurality of electrodes is configured as an active electrode.

10. The device according to claim 9, further comprising: A circuit configured to detect noise affecting the device; and A third corresponding electrode of the plurality of electrodes, the third corresponding electrode being configured to supply a stimulation signal to a user of the device, wherein the stimulation signal is associated with reducing detected noise.

11. The device according to claim 1, further comprising: Processing circuitry; One or more amplifiers, said one or more amplifiers being coupled to the respective electrode pairs; One or more analog-to-digital converters, wherein the resolution of each of the one or more analog-to-digital converters is variable; and A communication circuit, which is communicatively coupled to the processing circuit and configured to transmit data associated with the physiological signal.

12. The device of claim 1, wherein the physiological signal is associated with one or more eye events.

13. The device of claim 1, wherein the plurality of electrodes comprises one or more electrooculography (EOG) sensors.

14. A method for detecting eye movement, the method comprising: One or more elastomer materials are coupled to corresponding electrode pairs in multiple electrode pairs; The respective electrode pairs and the one or more elastomeric materials are brought into contact with the tissue associated with the user's eye; Physiological signals are received at the corresponding electrode pairs; The shape of the one or more elastomeric materials and the corresponding coupled electrode pairs is altered based on the received physiological signals to improve the contact between the corresponding electrode pairs and the user's tissue. as well as Physiological signals are sensed from the corresponding electrode pairs, and these physiological signals are associated with eye movements.

15. The method of claim 14, wherein the one or more elastomeric materials comprise dielectric elastomeric materials.

16. The method of claim 14, further comprising: The shape of the one or more elastomeric materials and the corresponding coupled electrode pairs is modified based on a first standard.

17. The method of claim 16, wherein the first criterion includes the amount of force applied by the respective electrode pair to the tissue of the user.

18. The method of claim 16, wherein the first criterion includes a threshold signal-to-noise ratio associated with the physiological signal.

19. The method of claim 14, wherein the respective electrode pair comprises one or more electrooculography (EOG) sensors.

20. A non-transitory computer-readable storage medium storing one or more programs, said one or more programs comprising instructions that, when executed by one or more processors of an electronic device, cause the electronic device to perform any one of the methods according to claims 14 to 19.

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