Two separate schemes are used for detecting light intensity in low light conditions and high light conditions. In high light conditions, two threshold voltages are set and the time between the crossing of a sensor voltage at the two threshold voltages is measured to determine the light intensity in the high light conditions. In low light conditions, a comparator is used to compare the voltage level of the sensor voltage relative to a reference voltage that increase over time. The time when the reference voltage reaches the sensor voltage level is detected to determine the light intensity in the low light conditions.

An apparatus comprising at least one pair of a first inner and second outer photodetector, each photodetector comprising a channel member, respective source and drain electrodes configured to enable a flow of electrical current through the channel member between the source and drain electrodes, and a plurality of quantum dots configured to generate electron-hole pairs on exposure to incident electromagnetic radiation to produce a detectable change in the electrical current flowing through the channel member. The first inner and second outer photodetectors are configured to generate electron-hole pairs which produce an increase and decrease in electrical current through the channel members. The first inner and the second outer photodetectors share a common channel member, which is partitioned by one or more of the respective source and drain electrodes respectively extending in two dimensions such that the first inner photodetector is defined within the second outer photodetector.

Disclosed are optical devices and methods of manufacturing optical devices. An optical device can include a substrate; an optical emitter chip affixed to the front surface of the substrate; and an optical sensor chip affixed to the front surface of the substrate. The optical sensor chip can include a main sensor and a reference sensor. The optical device can include an opaque dam separating the main optical sensor and the reference sensor. The optical device can include a first transparent encapsulation block encapsulating the optical emitter chip and the reference optical sensor and a second transparent encapsulation block encapsulating the main optical sensor. The optical device can include an opaque encapsulation material encapsulating the first transparent encapsulation block and the second transparent encapsulation block with a first opening above the main optical sensor and a second opening above the optical emitter chip.

The present disclosure provides an optical system suitable for detecting muzzle flashes in a scene, the optical system comprising: a first optical module customized for detecting flashes at short range of the optical system by analyzing irradiance received on a first infrared sensor; a second optical module customized for detecting flashes at long range of the optical system by analyzing irradiance received on a second infrared sensor; wherein: the first and second optical modules are configured to share a common field of view and to operate independently of each other.

A diamond identification apparatus is disclosed, the diamond identification apparatus comprising a support platform for receiving a gemstone at an observation position, a first light source arranged to emit light at a predetermined angle towards the observation position and a first photodiode arranged to detect an amount of light from the first light source being reflected from the gemstone at the observation position. The diamond identification apparatus further comprises a second light source arranged to emit light towards the observation position, a second photodiode arranged to detect light from the second light source that passes through the gemstone at the observation position and a processor unit.

Embodiments relate generally to gas detector systems and method, wherein a gas detector system may comprise at least one emitter configured to emit radiation in a beam path; at least one detector configured to receive at least a portion of the emitted radiation, wherein the emitted radiation generates at least two focused spots at the at least one detector; a ring reflector configured to direct the emitted radiation around the ring reflector toward the at least one detector, wherein the ring reflector comprises at least a portion of a spheroid shape, and wherein the ring reflector is configured to allow gas to flow through at least a portion of the beam path; and a processing circuit coupled to the one or more detectors configured to processes an output from the one or more detectors.

Apparatus and associated methods relate to determining the wavelength of a narrow-band light beam. Two portions of the narrow-band light beam are projected onto two dissimilar photodetectors, respectively. The two dissimilar photodetectors have dissimilar spectral responses over a domain of wavelengths that includes the wavelength of the narrow-band light beam. Each of the two dissimilar photodetectors generates an output signal indicative of a photocurrent induced by the projection of the portion of the narrow-band light beam thereon. A ratio of the differences between the photocurrents to the sum of the photocurrents of the two dissimilar photodetectors is determined. The determined ratio is a monotonic function of wavelength over the domain wavelengths including the wavelength of the narrow-band light beam. The determined ratio is thereby indicative of the wavelength of the narrow-band light beam.

An optical liquid height determination system of the present embodiments includes light sensors capturing different amounts of light, based on level of liquid in the tank that blocks or limits light to particular sensors. The tank is enclosed in a container with a light source and the light sensors are installed on walls of the container. Light emitted by the light source is transmitted to the light sensors by passing through the liquid product, scattered, diffused, diffracted or reflected by the dairy product, through the tank walls which may be transparent or translucent, or from other surfaces in the container within which the tank is enclosed by. The set of electrical signals received from all the light sensors are compared against sets of calibrated signals corresponding to known liquid levels in the tank. The known height corresponding to the nearest set of calibrated signals is determined as the measured liquid height in the tank.

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.

A light intensity detection method includes: determining whether light intensity detection needs to be performed; detecting whether there is a finger touch in an optical detection region of an optical fingerprint sensor if light intensity detection needs to be performed, wherein the optical detection region is located in at least one part of a display region of a display; enabling a light intensity detection function if no finger touch is detected, and collecting light intensity data by using the optical fingerprint sensor; and processing the collected light intensity data, and calculating a value of current ambient light intensity according to the light intensity data.