An electronic device is described. The electronic device may include a housing, a rotatable crown, and a self-mixing interferometry (SMI) sensor positioned within the housing. The rotatable crown may include an array of retroreflective surface features that reflect incident light back to a light source. Each retroreflective surface feature of the array of retroreflective surface features may be formed as a corner-cube with three perpendicular faces. The SMI sensor or associated processing electronics may compare originally emitted light with reflected light to identify a movement or distance of the rotatable crown with respect to the SMI sensor.

A reflective optical encoder has a hub member mounted on a rotation shaft, and a circular scale plate fixed to the hub member by an adhesive and having, on a front surface thereof, a pattern composed of high reflection portions having a high light reflectance and low reflection portions having a low light reflectance. Further, a step is provided at an outer peripheral portion of the hub member, and an outer diameter of the scale plate is larger than an outer diameter at an outermost peripheral portion of an adhesive surface of the hub member in which the scale plate and the hub member are bonded.

Photonic processors are described. The photonic processors described herein are configured to perform matrix-matrix (e.g., matrix-vector) multiplication. Some embodiments relate to photonic processors arranged according to a dual-rail architecture, in which numeric values are encoded in the difference between a pair optical signals (e.g., in the difference between the powers of the optical signals). Relative to other architectures, these photonic processors exhibit increased immunity to noise. Some embodiments relate to photonic processors including modulatable detector-based multipliers. Modulatable detectors are detectors designed so that the photocurrent can be modulated according to an electrical control signal. Photonic processors designed using modulatable detector-based multipliers are significantly more compact than other types of photonic processors.

Photonic processors are described. The photonic processors described herein are configured to perform matrix-matrix (e.g., matrix-vector) multiplication. Some embodiments relate to photonic processors arranged according to a dual-rail architecture, in which numeric values are encoded in the difference between a pair optical signals (e.g., in the difference between the powers of the optical signals). Relative to other architectures, these photonic processors exhibit increased immunity to noise. Some embodiments relate to photonic processors including modulatable detector-based multipliers. Modulatable detectors are detectors designed so that the photocurrent can be modulated according to an electrical control signal. Photonic processors designed using modulatable detector-based multipliers are significantly more compact than other types of photonic processors.

There is provided an optical encoder including an encoding medium and a substrate. The encoding medium has a relative movement with respect to the substrate in a predetermined direction. The substrate includes an index photodiode and two control photodiodes. The index photodiode is arranged between the two control photodiodes along the predetermined direction. The output signals of the two control photodiodes are for controlling ON/OFF of gain regulation on an output signal of the index photodiode so as to turn on the gain regulation within an interval during which the index photodiode does not generate an index pulse but to turn off the gain regulation within an interval during which the index photodiode generates the index pulse.

A rotational structure is configured such that a hollow portion, in which a base member is opposed to a rotational member, is formed around a shaft member. An encoder provided in the hollow portion includes a detection target member rotated together with one of the rotational member and the base member and having a physical quantity changing in a circumferential direction, and a detector capable of detecting the physical quantity of the detection target element and rotated together with the other of the rotational member and the base member.

A linear rotary encoder includes a pair of rotational surfaces. A contact belt has a first end coupled to a first rotational surface in the pair and a second end coupled to a second rotational surface in the pair. The contact belt is driven to rotate around the pair of rotational surfaces by a driving force applied to media to move the media from the first end toward the second end. An encoding scale is coupled to an inner surface of the contact belt. A reader is positioned to read the encoding scale as the contact belt rotates around the pair of rotational surfaces. The reader generates an output signal indicating a position of the media based on reading of the encoding scale.

The rotation detection apparatus including an annular member, a scale member having flexibility and being fixed to a circumferential portion of the annular member, and a detector facing the scale member and configured to detect relative rotation between the scale member and the detector. The circumferential portion of the annular member includes multiple convex portions and multiple concave portions along a circumferential direction of the annular member. The scale member is in contact with the multiple convex portions. Both ends, in the circumferential direction, of the scale member are fixed to the circumferential portion.

In order to provide a detection device that can accurately detect thermal deformation in any state including a case where thermal deformation has already occurred, there is provided a detection device which includes: a scale with a strained grating; and two sensor heads mounted on a pedestal at a predetermined distance, the sensor heads detecting positions on the scale based on the grating. Thermal deformation of the pedestal or the scale is detected based on a change in a difference between the positions detected by the two sensor heads.

An encoder includes a scale and a sensor. The scale has first and second absolute patterns. The sensor includes a light source, and first and second absolute light receivers. The first and second absolute light receivers receive light from the first and second absolute patterns, respectively. The first absolute light receiver receives light from the first pattern and includes first and second light receiving elements. Each first light receiving elements outputs a first signal with a first phase. Each second light receiving elements outputs a first signal with a second phase. The first and second light receiving elements are arranged alternately. The second absolute light receiver includes third and fourth light receiving elements. Each third light receiving element outputs a second signal with the first phase. The third and fourth light receiving elements are arranged alternately. Each fourth light receiving element outputs a second signal with the second phase.