Abstract: Improvements to gratings for use in waveguides and methods of producing them are described herein. Deep surface relief gratings (SRGs) may offer many advantages over conventional SRGs and Bragg gratings, an important one being a higher S-diffraction efficiency. In one embodiment, deep SRGs can be implemented as polymer surface relief gratings or evacuated Bragg gratings (EBGs). EBGs can be formed by first recording a holographic polymer dispersed liquid crystal (HPDLC) grating. Removing the liquid crystal from the cured grating provides a polymer surface relief grating. Polymer surface relief gratings have many applications including for use in waveguide-based displays.

Abstract: Improving the accuracy of ultrasonic touch sensing and fingerprint imaging using acoustic impedance matching is disclosed. Acoustic impedance mismatches between an ultrasonic transducer array and a sensing plate can be reduced to maximize energy transfer and minimize parasitic reflections. A reduction in acoustic impedance mismatches can be accomplished using (i) a composite epoxy having a higher acoustic impedance than epoxy alone, (ii) one or more matching layers having an acoustic impedance that is approximately the geometric mean of the acoustic impedance of the sensing plate and the acoustic impedance of the transducer array, (iii) pores or perforations in the sensing plate, or (iv) geometric structures formed in the sensing plate. In addition, parasitic reflections can be suppressed using an absorbent layer.

Abstract: Improving the accuracy of ultrasonic touch sensing and fingerprint imaging using acoustic impedance matching is disclosed. Acoustic impedance mismatches between an ultrasonic transducer array and a sensing plate can be reduced to maximize energy transfer and minimize parasitic reflections. A reduction in acoustic impedance mismatches can be accomplished using (i) a composite epoxy having a higher acoustic impedance than epoxy alone, (ii) one or more matching layers having an acoustic impedance that is approximately the geometric mean of the acoustic impedance of the sensing plate and the acoustic impedance of the transducer array, (iii) pores or perforations in the sensing plate, or (iv) geometric structures formed in the sensing plate. In addition, parasitic reflections can be suppressed using an absorbent layer.

Abstract: An electronic device may include an infrared light source and an infrared image sensor to enable infrared beacon functionality. In a location sharing scenario, a first electronic device may use the infrared light source to emit infrared light and serve as an infrared beacon. A second electronic device may use the infrared image sensor to detect the infrared beacon and identify the location of the first electronic device. The infrared image sensor that is used to detect the infrared beacon may also serve as a time-of-flight sensor for a light detection and ranging (LiDAR) module. The second electronic device (that detects the infrared beacon) may provide output such as visual, audio, and/or haptic output to inform a user of the location of the infrared beacon.

Abstract: Embodiments are disclosed for a gyroscopic precession engine for wearable devices. In an embodiment, a wearable device comprises: a support structure including at least one attachment mechanism for attaching the support structure to a human body part; at least one gyroscopic precession engine coupled to the support structure, the gyroscopic precession engine, comprising: a first motor configured to rotate a wheel mount at a first angular velocity; at least one wheel rotatably coupled to the wheel mount and configured to spin at a second angular velocity different than the first angular velocity; a second motor configured to spin the wheel at the second angular velocity; and at least one motor controller coupled to the first motor and the second motor, the at least one motor controller configured to rotate the wheel mount at the first angular velocity and spin the wheel at the second angular velocity, thereby producing a torque in a desired direction.

Abstract: Improving the accuracy of ultrasonic touch sensing and fingerprint imaging using acoustic impedance matching is disclosed. Acoustic impedance mismatches between an ultrasonic transducer array and a sensing plate can be reduced to maximize energy transfer and minimize parasitic reflections. A reduction in acoustic impedance mismatches can be accomplished using (i) a composite epoxy having a higher acoustic impedance than epoxy alone, (ii) one or more matching layers having an acoustic impedance that is approximately the geometric mean of the acoustic impedance of the sensing plate and the acoustic impedance of the transducer array, (iii) pores or perforations in the sensing plate, or (iv) geometric structures formed in the sensing plate. In addition, parasitic reflections can be suppressed using an absorbent layer.

Abstract: An ultrasonic touch sensing system that uses both compressional and shear waves for touch and water detection is disclosed. When no touch or water is present, less shear and compressional wave energy is absorbed, so both shear and compressional wave reflections do not have significant amplitude decreases. When a finger is in contact with the sensing plate, both shear and compressional wave energy is absorbed, so both shear and compressional wave reflections have significant amplitude decreases. When water is in contact with the sensing plate, compressional energy is absorbed but little or no shear wave energy is absorbed, so while compressional wave reflections have significant amplitude decreases, shear wave reflections do not. From these amplitudes, a determination can be made as to whether no touch is present on the sensing plate, whether a touch is present on the sensing plate, or whether water is present on the sensing plate.

Abstract: Ultrasonic force detection systems and methods can be based on propagation of ultrasonic waves in a user's body (e.g., in a user's digit). An amount of force can be determined using time-of-flight (TOF) techniques of one or more ultrasonic waves propagating in the user's body. In some examples, an electronic device including a transducer can be coupled to a digit, and can transmit ultrasonic waves into the digit. As the wave propagates through the thickness of the digit, a reflection of at least a portion of the transmitted wave can occur due to the bone and/or due to reaching the opposite side of the digit (e.g., finger pad). One or more reflections can be measured to determine the amount of force.

Abstract: Improving the accuracy of ultrasonic touch sensing via the reduction, elimination and/or rejection of parasitic ultrasonic reflections caused by unintended touches is disclosed. The adverse effects of these parasitic reflections can be mitigated by disrupting the symmetry of the true reflections (from the intended touch) and the parasitic reflections (from unintended touches) so that the true touch can be disambiguated from unintended touches. Identification of the true touch can then enable accurate touch localization.

Abstract: Improving the accuracy of ultrasonic touch sensing via the reduction, elimination and/or rejection of parasitic ultrasonic reflections caused by unintended touches is disclosed. The adverse effects of these parasitic reflections can be mitigated by disrupting the symmetry of the true reflections (from the intended touch) and the parasitic reflections (from unintended touches) so that the true touch can be disambiguated from unintended touches. Identification of the true touch can then enable accurate touch localization.

Abstract: An ultrasonic touch sensing system that uses both compressional and shear waves for touch and water detection is disclosed. When no touch or water is present, less shear and compressional wave energy is absorbed, so both shear and compressional wave reflections do not have significant amplitude decreases. When a finger is in contact with the sensing plate, both shear and compressional wave energy is absorbed, so both shear and compressional wave reflections have significant amplitude decreases. When water is in contact with the sensing plate, compressional energy is absorbed but little or no shear wave energy is absorbed, so while compressional wave reflections have significant amplitude decreases, shear wave reflections do not. From these amplitudes, a determination can be made as to whether no touch is present on the sensing plate, whether a touch is present on the sensing plate, or whether water is present on the sensing plate.

Abstract: Ultrasonic force detection systems and methods can be based on propagation of ultrasonic waves in a user's body (e.g., in a user's digit). An amount of force can be determined using time-of-flight (TOF) techniques of one or more ultrasonic waves propagating in the user's body. In some examples, an electronic device including a transducer can be coupled to a digit, and can transmit ultrasonic waves into the digit. As the wave propagates through the thickness of the digit, a reflection of at least a portion of the transmitted wave can occur due to the bone and/or due to reaching the opposite side of the digit (e.g., finger pad). One or more reflections can be measured to determine the amount of force.

Abstract: Acoustic touch sensing system architectures and methods for acoustic touch sensing can be used to detect a position of an object touching a surface. Acoustic touch sensing can utilize transducers (e.g., piezoelectric) to simultaneously transmit ultrasonic waves along a surface and through a thickness of a material. The location of the object can be determined based on the amount of time elapsing between the transmission of the waves and receipt of the reflected waves. In some examples, an acoustic touch sensing system can be insensitive to water contact on the device surface, and thus acoustic touch sensing can be used for touch sensing in devices that may become wet or fully submerged in water. In some examples, techniques such as isolation and absorption of acoustic energy can be used to mitigate acoustic energy reflected by portions of the electronic device and interfere with the acoustic touch sensing operation.

Abstract: Acoustic touch sensing system architectures and methods for acoustic touch sensing can be used to detect a position of an object touching a surface. Acoustic touch sensing can utilize transducers (e.g., piezoelectric) to simultaneously transmit ultrasonic waves along a surface and through a thickness of a material. The location of the object can be determined based on the amount of time elapsing between the transmission of the waves and receipt of the reflected waves. In some examples, an acoustic touch sensing system can be insensitive to water contact on the device surface, and thus acoustic touch sensing can be used for touch sensing in devices that may become wet or fully submerged in water. In some examples, techniques such as isolation and absorption of acoustic energy can be used to mitigate acoustic energy reflected by portions of the electronic device and interfere with the acoustic touch sensing operation.

Abstract: This relates to system architectures, apparatus and methods for acoustic touch detection (touch sensing) and exemplary applications of the system architectures, apparatus and methods. In some examples, the acoustic touch sensing techniques described herein can be used on a glass surface of a display or touch screen. In some examples, an acoustic touch sensing system can be configured to be insensitive to contact on the device surface by water, and thus acoustic touch sensing can be used for touch sensing in devices that are likely to become wet or fully submerged in water.

Abstract: Touch sensitive mechanical keyboards and processes for detecting touch events and key depressions on the touch sensitive mechanical keyboard are provided. The touch sensitive mechanical keyboard can include a set of individually depressible mechanical keys having a touch sensitive surface. A touch sensor layer can be disposed on top of a key mechanism and flexible interconnections provided between key segments of the touch sensor layer can allow for depression of the key mechanism of individual keys. In some examples, the flexible interconnections can be formed by patterning a spring-like structure into the touch sensor layer. In some examples, the touch sensor layer can be transparent or include openings to allow a backlight to shine through. In some examples, addressable LED backlighting with buckling interconnects can also be provided to illuminate keycaps of the mechanical keyboard.

Abstract: Acoustic touch sensing systems can include a mechanically integrated structure including multiple acoustic transducers. For example, an annular structure including one or more piezoelectric segments can be fabricated and then coupled to a front crystal/cover glass. A single structure can simplify the structural integration of the device, can provide a mechanically reliable and stable structure for improved structural integrity of the system, and can provide for improved water sealing for a waterproof or water resistant device. The piezoelectric material in the annular structure can be shear poled such that a poling direction of the piezoelectric material can follow the curvature of the annular piezoelectric structure.

Abstract: Touch sensitive mechanical keyboards and processes for detecting touch events and key depressions on the touch sensitive mechanical keyboard are provided. The touch sensitive mechanical keyboard can include a set of individually depressible mechanical keys having a touch sensitive surface. A touch sensor layer can be disposed on top of a key mechanism and flexible interconnections provided between key segments of the touch sensor layer can allow for depression of the key mechanism of individual keys. In some examples, the flexible interconnections can be formed by patterning a spring-like structure into the touch sensor layer. In some examples, the touch sensor layer can be transparent or include openings to allow a backlight to shine through. In some examples, addressable LED backlighting with buckling interconnects can also be provided to illuminate keycaps of the mechanical keyboard.

Abstract: Acoustic touch sensing systems can include a mechanically integrated structure including multiple acoustic transducers. For example, an annular structure including one or more piezoelectric segments can be fabricated and then coupled to a front crystal/cover glass. A single structure can simplify the structural integration of the device, can provide a mechanically reliable and stable structure for improved structural integrity of the system, and can provide for improved water sealing for a waterproof or water resistant device. The piezoelectric material in the annular structure can be shear poled such that a poling direction of the piezoelectric material can follow the curvature of the annular piezoelectric structure.

Abstract: This relates to system architectures, apparatus and methods for acoustic touch detection (touch sensing) and exemplary applications of the system architectures, apparatus and methods. In some examples, the acoustic touch sensing techniques described herein can be used on a glass surface of a display or touch screen. In some examples, an acoustic touch sensing system can be configured to be insensitive to contact on the device surface by water, and thus acoustic touch sensing can be used for touch sensing in devices that are likely to become wet or fully submerged in water.