An external element of a timepiece including a frame made of a first material, the external element further including at least one light sensor.

This disclosure relates to measuring ultraviolet (UV) exposure. One example system includes an electronic sensor chip that includes a UV sensor that measures a UV intensity reading, an inertial measurement unit that acquires movement data of the UV sensor, and at least one processor. The system further includes a light pipe that guides light towards the UV sensor and a diffuser that has an angle-dependent transmission function and covers an end of the light pipe. Example operations can be performed by the processor include determining a solar incidence angle between a direction of the sun and a normal direction of the UV sensor, computing an estimation of a maximum UV intensity at normal incidence based on the UV intensity reading, the solar incidence angle, and the angle-dependent transmission function of the diffuser, and outputting a UV index based on the estimation of the maximum UV intensity at normal incidence.

An extreme ultraviolet light generating apparatus includes: EUV light sensors configured to measure energy of extreme ultraviolet light from mutually different directions, the extreme ultraviolet light being generated by applying laser light to a target supplied to a predetermined region in a chamber; an application position adjusting unit configured to adjust an application position of the laser light to the target supplied to the predetermined region; and a controller configured to control the application position adjusting unit such that a centroid of the extreme ultraviolet light becomes a targeted centroid, the centroid of the extreme ultraviolet light being specified from measurement results of the EUV light sensors, the controller controlling the application position adjusting unit such that the application position is scanned in accordance with reference scan points mutually different in position, and calibrating the targeted centroid based on the measurement results acquired for the reference scan points.

One variation of a method for measuring ambient ultraviolet light radiation including: calculating a target direct orientation of a light exposure device based on a location, a current date and time, and a direct solar position model; calculating a target diffuse orientation of the light exposure device based on the location, the current date and time, and a diffuse solar position model; in response to detecting alignment between orientation of the light exposure device and the target direct orientation, recording a direct ultraviolet value; in response to detecting alignment between orientation of the light exposure device and the target diffuse orientation, recording a diffuse ultraviolet value; in response to detecting alignment between orientation of the light exposure device and a target global orientation, recording a global ultraviolet value; and calculating an ultraviolet index based on the global ultraviolet value, the direct ultraviolet value, and the diffuse ultraviolet value.

The present invention relates to a detector assembly and method incorporating angled sensors, such that the area of coverage and detection sensitivity are maximized. The present invention finds particular applicability in the detection of sparks and the like in the presence of combustible gases, dusts, and the like via optical, infrared (IR), and ultraviolet (UV) methodologies and the like.

Techniques are provided to furnish a light sensor that includes a filter positioned over a photodetector to filter visible and infrared wavelengths to permit the sensing of ultraviolet (UV) wavelengths. In one or more implementations, the light sensor comprises a semiconductor device (e.g., a die) that includes a substrate. A photodetector (e.g., photodiode, phototransistor, etc.) is formed in the substrate proximate to the surface of the substrate. In one or more implementations, the substrate comprises a silicon on insulator substrate (SOI). A filter (e.g., absorption filter, interference filter, flat pass filter, McKinlay-Diffey Erythema Action Spectrum-based filter, UVA/UVB filter, and so forth) is disposed over the photodetector. The filter is configured to filter infrared light and visible light from light received by the light sensor to at least substantially block infrared light and visible light from reaching the photodetector. The thickness of the SOI substrate can be tailored to modify received UV/visible wavelength ratios.

A UV dosimeter function is provided in a portable multifunction device. The device utilizes a UV light sensor to detect the user's presence while outdoors and measure the cumulative outdoor exposure time. The cumulative UV exposure is optionally provided via a messaging service or alert, and a UV index value is optionally utilized with the cumulative outdoor exposure to determine the risk of skin damage and to provide user guidance relating to recommended protective measures. An ambient light sensor is optionally provided and is used to augment the UV light thresholds used to determine the light exposure state.

Provided is a solid-state light-receiving device for ultraviolet light, which is capable of measuring an irradiation amount of UV-rays, which are harmful to a human body, accurately and appropriately with a simple structure, and of being formed easily and integrally with sensors of peripheral circuits, and which is small, lightweight, low cost, and suitable for mobile or wearable applications. The solid-state light-receiving device for ultraviolet light includes a first photodiode, a second photodiode, and a differential circuit to which signals based on outputs of those photodiodes are input. The solid-state light-receiving device for ultraviolet light also includes semiconductor layer regions, which are formed in and on the above-mentioned photodiodes, and each of which includes a highest concentration position of semiconductor impurities.

In accordance with at least one aspect of this disclosure, an ultraviolet radiation (UV) sensor includes a UV sensitive material and a first electrode and a second electrode connected in series through the UV sensitive material such that UV radiation can reach the UV sensitive material. The UV sensitive material can include at least one of zinc tin oxide, magnesium oxide, magnesium zinc oxide, or zinc oxide. The electrodes can be interdigitated comb electrodes.

A flame sensor detects the presence of a flame in a combustion system in which the flame emits light. The flame sensor includes a body connectable with the combustion system. A photodetector is supported in the body. The photodetector responds to light emitted by the flame and generates an electrical signal proportional to an intensity of the light. A window is supported in the body and located between the combustion system and photodetector. The window is susceptible to contamination from the combustion system and the contamination may decrease sensitivity of the photodetector. A light source is supported in the body. The light source emits light so that a predetermined amount of the light emitted by the light source reflects into the photodetector when contamination is present on the window and the photodetector generates a signal indicative of contamination on the window.