A system includes a sensor for measuring a skin parameter. The sensor includes at least three spatially separated light sources for providing unpolarized visible light, a detector located at a first distance from each of the light sources selected from the range of 10-80 mm and at a second distance from the skin, and a polarizer including one or more of a segmented polarizer and a spatially varying polarizer. In a sensing mode, the light sources are configured to sequentially illuminate the skin with the light with optical axes at an angle of incidence selected from the range of 10°-80°, and the detector is configured to sequentially detect light reflected from the skin and generate corresponding detector signals.

Systems, methods, and apparatus for differential phase contrast microscopy by transobjective differential epi-detection of forward scattered light are provided. In some embodiments, a microscope objective comprises: a housing with mounting threads at a second end; optical components defining an optical axis, comprising: an objective lens mounted at a first end, configured to collect light from a sample placed in a field of view, the plurality of optical components create a pupil plane at a first distance along the optical axis at which rays having the same angle of incidence on the objective lens converge at the same radial distance from the optical axis; a photodetector within the housing offset from the optical axis at a second distance along the optical axis; and another photodetector within the housing at second distance along the optical axis and offset from the optical axis in the opposite direction from the first photodetector.

The invention comprises a method and apparatus for sampling skin of a person as a part of noninvasive analyte property determination system, comprising the steps of: providing an analyzer, comprising: sources and at least three detectors at least partially embedded in a probe housing, the probe housing comprising a sample side surface, the detectors including: a range of differing radial distances from a first illumination zone; repetitively illuminating an illumination zone of the skin with photons in a range of 1200 to 2500 nm; detecting portions of the first photons with the at least three detectors; and using signals from the at least three detectors and a metric, respectively classifying the skin into a first, second, and third tissue state, the radial distances of the at least three detectors differing from each other by greater than ten percent.

A solid-state gas spectrometer for detection of molecules of target gases. An emitter generates light having wavelengths both within and outside of one or more absorption bands of a target molecule. The light provided by the emitter passes through an airway adapter. A reflective beam splitter splits the light transmitted through the airway adapter, into two convergent beams each focused on a light detector. One of the light detectors, which is covered by a filter that rejects light having wavelengths within one or more absorption bands of the target molecule, serves as the sensing detector. The other light detector, which may or may not be covered by a filter, serves as the reference detector. The concentration of a target gas molecule in the gas sample is estimated based on a differential signal that is generated using the signals received from the reference and sensing detectors.

Disclosed is an optical probe of an optical coherence tomography (OCT) system according to an exemplary embodiment of the present disclosure. The optical probe of the OCT system includes: an optical fiber receiving light generated from a light source and transferring the received light to a plurality of lenses and receiving light reflected from tissue from the plurality of lenses and transferring the received light to an optical coherence system; a plurality of lenses including a first lens positioned at a distal end of the optical fiber and a second lens positioned at a predetermined point in a longitudinal direction of the optical fiber; and a sheath capable of accommodating the optical fiber therein.

A photoplethysmogram (PPG) sensor includes a pixel array that collects light, a pixel sampler that converts the light collected through the pixel array into a plurality of pixel data, an effective area determiner that determines an effective area and a non-effective area of the pixel array based on the pixel data, a power controller that is operable to cut off power to the non-effective area of the pixel array, and a PPG data generator that generates PPG data from pixel data corresponding to the effective area among the pixel data.

Provided is an apparatus configured to estimate bio-information, the apparatus including a pulse wave sensor including a plurality of channels disposed in an isotropic shape, a force sensor configured to measure a force applied by an object to the pulse wave sensor, and a processor configured to detect a center of gravity based on pressure, applied by the object, in a space formed by the plurality of channels based on pulse wave signals measured by each of the plurality of channels included in the pulse wave sensor, provide a user with guide information with respect to contact of the object to the pulse wave sensor based on the detected center of gravity, and estimate bio-information based on the pulse wave signals and the force which are measured based on the guide information.

A photoplethysmographic (PPG) device is disclosed. The PPG device can include one or more light emitters and one or more light sensors to generate the multiple light paths for measuring a PPG signal and perfusion indices of a user. The multiple light paths between each pair of light emitters and light detectors can include different separation distances to generate both an accurate PPG signal and a perfusion index value to accommodate a variety of users and usage conditions. In some examples, the multiple light paths can include the same separation distances for noise cancellation due to artifacts resulting from, for example, tilt and/or pull of the device, a user's hair, a user's skin pigmentation, and/or motion. The PPG device can further include one or more lenses and/or reflectors to increase the signal strength and/or and to obscure the optical components and associated wiring from being visible to a user's eye.

A photovoltaic unit that includes a biological interface for sensing an electrical signal from the biological tissue, the biological interface including a multilayered piezoelectric amplifier including a composite impulse generating layer including a matrix of a piezo polymeric material and dispersed phases including piezo nanocrystals and carbon nanotubes. The photovoltaic unit also includes a transducer structure comprising a fiber substrate having quantum dots present on a receiving end of the fiber. The receiving end of the fiber receiving the electrical signal. The quantum dots converts the electrical signal to a light signal.

A measurement apparatus includes a light source, a sensor including light detection cells including a first light detection cell and a second light detection cell, and an electronic circuit. The circuit causes the light source to emit a light pulse, causes the first light detection cell to detect a reflected light pulse from a target in an exposure period including at least part of a period from when an intensity of the reflected light pulse starts increasing to when it starts falling and generate a first signal, causes the second light detection cell to detect the reflected light pulse in an exposure period including at least part of a trailing period from when the intensity of the reflected light pulse starts falling to when it stops falling and generate a second signal. The circuit generates, based on the first and second signals, data representing states of the target.