In some examples, an optical encoder may consist of a light source that shines light onto a wheel which then reflects the light onto a sensor. Using information encoded in the reflected light, the rotation of the wheel may be determined. In some examples, rotation of the wheel may be determined by detecting an encoding pattern in light reflected from an exterior surface of the wheel. In some examples, the encoding pattern can be a pattern of light and dark stripes. In some examples, a pattern of light stripes can be generated from light reflecting off of reflective portions of the wheel. Some examples of the disclosure relate to using a surface topology for a wheel that can be used to generate an encoding pattern of light and dark stripes in light reflected from the surface of the wheel, even when the surface of the wheel is uniformly reflective.

A timing apparatus, system, and method are provided to determine a position of a rotating object in a device, such as an engine, and control the device according to the determined position of the rotating object. Light is emitted from a light source onto a reflecting region on a portion of the rotating object. Light is reflected off the reflecting region of the rotating object and detected as the rotating object rotates. Intensity of the reflected light is measured, via a microcontroller, and the position of the rotating object is determined according to the intensity of the detected light. A signal is generated that corresponds to the intensity of the detected light associated with the determined position of the rotating shaft. The reflecting region has a feature configured to effect a change in the intensity of the reflected light as the rotating object rotates. The microcontroller is configured to determine the determined position and to utilize the determined position and the change in the signal to control operating characteristics of the device.

An optical microcavity device (10), an alignment structure for an optical device, and a method for aligning an optical device are disclosed. The optical microcavity device (10) comprises: a first optical reflector (20); a second optical reflector (30) opposed to the first optical reflector (20) along an optical axis (40), the first and second optical reflectors (20, 30) being spaced from each other forming an open space therebetween; wherein the first optical reflector (20) comprises a first cavity reflector (22) and a first alignment reflector (24), wherein the second optical reflector (30) comprises a second cavity reflector (32) and a second alignment reflector (34), the second cavity reflector (32) comprising a recess to provide an optical microcavity between the first and second cavity reflectors (20, 30), the optical microcavity having an optical cavity length of at most 50 μm and/or an optical mode volume of 100 μm3 or less; an EM radiation source (50) configured for illuminating the optical microcavity with EM radiation (52) to cause multi-pass interference within the optical microcavity; and an alignment system configured to: illuminate the first and second alignment reflectors (24, 34) of the first and second optical reflectors (20, 30) to generate an optical interference pattern (74); detect the optical interference pattern (74); and determine a relative orientation and/or separation of the first and second optical reflectors (20, 30) based on the detected optical interference pattern (74); the alignment system further comprising an actuator system (100, 102) configured to move the first and second optical reflectors (20, 30) relative to each other to change the relative orientation and/or separation of the first and second optical reflectors (20, 30) based on the determined relative orientation and/or separation. At least one of the first and second alignment reflectors (20, 30) may comprise an alignment structure comprising at least two reflective surface portions having different angular orientations.

The range of operating angles of a position transducer is widened, and its signal-to-noise ratio is improved. The position transducer includes a light source and a detector including at least one pair of photodiodes (PDs) disposed on a predetermined circle. The detector receives light emitted from the light source to output a signal varying depending on the areas of regions where the light is received on two PDs forming a pair. The PDs are formed on separate chips, respectively, and the chips are disposed on a substrate so that one or more pairs of PDs surround the entirety of a predetermined region and have an annular shape as a whole.

The position detector of an object comprises a body defining an input receiving an optical fibre delivering a light signal, and an output delivering a signal representative of the position of the object. A mirror is mounted to move between first and second positions in the body with respect to the input. The first position or the second position ensures transmission of the light signal from the input to the output. The other of the first position and the second position prevents transmission of the light signal to the output. A spring is mounted in the body in order to place the mirror in the first position. A tip is movable relative to the body between a first position and a second position along a direction of movement and is intended to cooperate with the object to be monitored.

A scale includes a diffraction grating configured to condense diffracted light in a periodic direction of the diffraction grating in order to detect a reference position. A light receiving element array is configured to receive light from the diffraction grating. The light receiving element array includes first to fourth light receiving elements configured to output signals having phases different from each other. The first light receiving element and the second light receiving element are adjacent to each other and are arranged between the third light receiving element and the fourth light receiving element. The processing unit generates a signal representing the reference position based on a differential signal between a signal from the first light receiving element and a signal from the third light receiving element and a differential signal between a signal from the second light receiving element and a signal from the fourth light receiving element.

The invention pertains to a contactless measurement method for detecting rotation of an object over an axis coinciding with an optical axis of a probe beam. The probe beam is comprised of two monochromatic wavelengths with circular polarizations of opposite chirality, having a frequency difference for providing a heterodyne probe beam. A neutral beam splitter is provided that directs a reflected beam via a polarizer filter towards a first photodetector and that directs a transmitted beam toward a quarter wave plate attached to a rotatable object. A mirror reflects the probe beam, via the same quarter wave plate, back into the neutral beam splitter, which directs the reflected beam via a polarizer filter toward a second photodetector. The rotation is derived from the relative phase difference between the first and second photodetector signals.

The range of operating angles of a position transducer is widened, and its signal-to-noise ratio is improved. The position transducer includes a light source and a detector including at least one pair of photodiodes (PDs) disposed on a predetermined circle. The detector receives light emitted from the light source to output a signal varying depending on the areas of regions where the light is received on two PDs forming a pair. The PDs are formed on separate chips, respectively, and the chips are disposed on a substrate so that one or more pairs of PDs surround the entirety of a predetermined region and have an annular shape as a whole.

New platform technologies to actuate and sense force propagation in real-time for large sheets of cells are provided. In certain embodiments the platform comprises a device for the measurement of mechanical properties of cells or other moieties, where device comprises a transparent elastic or viscoelastic polymer substrate disposed on a rigid transparent surface; and a plurality of micromirrors disposed on or in said polymer substrate, wherein the reflective surfaces of the micromirrors are oriented substantially parallel to the surface of said polymer substrate. In certain embodiments the device comprises more than about 1,000,000, or more than about 10,000,000 micromirrors. In certain embodiments the micromirrors comprise a magnetic layer and/or a diffraction grating.

This application discloses a tactile sensor, a detection method for a touch event, a sensing device and a robot, and belongs to the field of sensor design. The tactile sensor includes: a sensing unit, an elastomer support housing and a base; the sensing unit is disposed in an inner cavity enclosed by the elastomer support housing and the base; and the sensing unit includes at least two light sources, a photo detector and a reflector, where the photo detector is disposed on base, the at least two light sources are disposed around the periphery of the photo detector on the base, and the reflector is disposed at the top of an inner cavity of the elastomer support housing. By adopting the combination of a plurality of light sources and one photo detector, the number of photo detectors for use is reduced, so that the volume of the tactile sensor is reduced.