An optical sensor arrangement comprises a photodiode (11), an integrator (12) with an integrator input (15) coupled to the photodiode (11), a comparator (13) with a first input (18) coupled to an integrator output (16) of the integrator (12), and a reference capacitor circuit (14) that is coupled to the integrator input (15) and is designed to provide a charge package to the integrator input (15). In a start phase (A), charge packages are provided to the integrator input (15), until a comparator input voltage (VIN) at the first input (18) of the comparator (13) crosses a comparator switching point.

An optical sensor arrangement comprises a photodiode (11), an integrator (12) with an integrator input (15) coupled to the photodiode (11), a comparator (13) with a first input (18) coupled to an integrator output (16) of the integrator (12), and a reference capacitor circuit (14) that is coupled to the integrator input (15) and is designed to provide a charge package to the integrator input (15). In a start phase (A), charge packages are provided to the integrator input (15), until a comparator input voltage (VIN) at the first input (18) of the comparator (13) crosses a comparator switching point.

An optical sensor arrangement has an integrator, a photodiode for providing a current corresponding to a first polarity, a comparator coupled to the integrator for comparing a voltage with a threshold voltage to provide a comparison output, a reference charge circuit and a control unit. The reference charge circuit is coupled to the integrator for selectively providing first charge packages of a first size or second charge packages of a second size. The control unit is configured to control operation in a calibration phase, in an integration phase and in a residual measurement phase. During the calibration phase, the reference charge circuit provides one of the first charge packages and one or more of the second charge packages to the integrator until the comparison output changes. A reference number is determined corresponding to a number of the second charge packages provided. During the integration phase, the photodiode is connected to the integrator and the reference charge circuit provides one of the first charge packages to the integrator in response to a respective change of the comparison output. An integration number corresponding to a number of the changes of the comparison output is determined. During the residual measurement phase that immediately follows the integration phase, the reference charge circuit provides one or more of the second charge packages to the integrator until the comparison output changes. A residual number corresponding to a number of the second charge packages provided is determined.

An optical sensor arrangement has an integrator, a photodiode for providing a current corresponding to a first polarity, a comparator coupled to the integrator for comparing a voltage with a threshold voltage to provide a comparison output, a reference charge circuit and a control unit. The reference charge circuit is coupled to the integrator for selectively providing first charge packages of a first size or second charge packages of a second size. The control unit is configured to control operation in a calibration phase, in an integration phase and in a residual measurement phase. During the calibration phase, the reference charge circuit provides one of the first charge packages and one or more of the second charge packages to the integrator until the comparison output changes. A reference number is determined corresponding to a number of the second charge packages provided. During the integration phase, the photodiode is connected to the integrator and the reference charge circuit provides one of the first charge packages to the integrator in response to a respective change of the comparison output. An integration number corresponding to a number of the changes of the comparison output is determined. During the residual measurement phase that immediately follows the integration phase, the reference charge circuit provides one or more of the second charge packages to the integrator until the comparison output changes. A residual number corresponding to a number of the second charge packages provided is determined.

A wearable computing device includes an electronic display with a configurable brightness level setting, a physiological metric sensor system including a light source configured to direct light into tissue of a user wearing the wearable computing device and a light detector configured to detect light from the light source that reflects back from the user. The device may further include control circuitry configured to activate the light source during a first period, generate a first light detector signal indicating a first amount of light detected by the light detector during the first period, deactivate the light source during a second period, generate a second light detector signal indicating a second amount of light detected by the light detector during the second period, generate a physiological metric based at least in part on the first light detector signal and the second light detector signal, and modify the configurable brightness level setting based on the second light detector signal.

A wearable computing device includes an electronic display with a configurable brightness level setting, a physiological metric sensor system including a light source configured to direct light into tissue of a user wearing the wearable computing device and a light detector configured to detect light from the light source that reflects back from the user. The device may further include control circuitry configured to activate the light source during a first period, generate a first light detector signal indicating a first amount of light detected by the light detector during the first period, deactivate the light source during a second period, generate a second light detector signal indicating a second amount of light detected by the light detector during the second period, generate a physiological metric based at least in part on the first light detector signal and the second light detector signal, and modify the configurable brightness level setting based on the second light detector signal.

A system, apparatus and method of improved measurement of the SPF factor of sunscreen compositions. In one embodiment, a method of measuring the protection of a sunscreen composition includes exposing skin to a known intensity of light, measuring the amount of remitted light from the skin, applying sunscreen to the skin, exposing the skin to which the sunscreen has been applied the known intensity of emitted light of the spectrum of light from which the sunscreen is intended to protect the skin, measuring the amount of light remitted from the skin, and calculating a UltraViolet-A Protection Factor (UVA-PF) of the sunscreen by comparing the amount of light remitted from the skin with the sunscreen to the amount of light remitted from the skin without the sunscreen.

A system, apparatus and method of improved measurement of the SPF factor of sunscreen compositions. In one embodiment, a method of measuring the protection of a sunscreen composition includes exposing skin to a known intensity of light, measuring the amount of remitted light from the skin, applying sunscreen to the skin, exposing the skin to which the sunscreen has been applied the known intensity of emitted light of the spectrum of light from which the sunscreen is intended to protect the skin, measuring the amount of light remitted from the skin, and calculating a UltraViolet-A Protection Factor (UVA-PF) of the sunscreen by comparing the amount of light remitted from the skin with the sunscreen to the amount of light remitted from the skin without the sunscreen.

To more appropriately adjust the brightness inside a vehicle. Provided is a system including: a first vehicle configured to output, to a server, information regarding illuminance of light incident on a vehicle by associating with information regarding a traveling environment; a second vehicle configured to output information regarding a traveling environment to the server; and the server including a controller configured to generate, based on the information regarding the illuminance of the light incident on the first vehicle, information regarding a sudden-change point that is a point at which a change amount of the illuminance of the light incident on the first vehicle exceeds a prescribed value, and configured to output, based on the information regarding the traveling environment of the second vehicle acquired from the second vehicle, information regarding the sudden-change point to the second vehicle.

In one respect, disclosed is a soiling measurement device for measuring the loss of light transmission to photovoltaic (PV) devices in a photovoltaic array arising from the accumulation of soiling particles, comprising a light source, a reference photodetector, a soiling collection window, a photodetector positioned underneath the soiling collection window, and a measurement and control system.