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.

Provided is a semiconductor light detection device having a relatively high detection sensitivity to a light component of a specific wavelength. The semiconductor light detection device includes: a semiconductor light receiving element, in which a first conductive layer is formed on a surface of a semiconductor substrate, a second conductive layer is formed below the first conductive layer, a third conductive layer is formed below the second conductive layer, and a photocurrent based on the intensity of incident light is output from the third conductive layer while an input voltage is applied to the first conductive layer; and a semiconductor detection circuit configured to output an output voltage based on a current difference between a first photocurrent and a second photocurrent being output in response to the application of the first input voltage and the second input voltage, respectively.

A detection unit includes multiple detection elements, which are configured to output intensities of received light as detection signals, and a light shielding portion, which is configured to regulate an incident angle of light with respect to the detection elements. The storage unit is configured to store a reference distribution indicating a distribution of intensity of light detected with the detection units caused by irradiation of reference light having a reference directivity characteristic on the detection unit. The calculation unit is configured to input the detection signals from the detection elements, to calculate the detection distribution of the intensity of received light, to input the reference distribution from the storage unit, to calculate a deviation of the detection distribution from the reference distribution, and to calculate a directivity characteristic of received light on the basis of the deviation.

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.

A detector has a sensor responsive to a first wavelength, a sensor responsive to a second wavelength, and a sensor for collecting reference readings. A gas sample is analyzed to obtain readings corresponding to the first wavelength, the second wavelength and a reference. A first absorption figure is calculated using the first reading and the reference reading, and a second absorption figure using the second reading and the reference reading. A linearizer function is applied to the first and second absorption figures to calculate first and second concentration figures. The sensor for each wavelength is calibrated for detecting the first gas such that the data collected at each wavelength gives the same reading when only the first gas is present. The ratio of the first concentration figure to the second concentration figure is used to identify whether only the first gas is present.

A display device includes a display, a first motor, an illuminance sensor, and a processor. The display displays information. The first motor changes a direction of a display surface of the display. The processor determines a first direction corresponding to a direction from a human sensor or the display surface to the eyes of the operator based on first sensing data output from the human sensor. The processor controls the first motor so that a normal direction of the display surface is the first direction when an illuminance of light incident from the first direction included in second sensing data output from the illuminance sensor is less than a first threshold. The processor controls the first motor so that the normal direction is a second direction different from the first direction when the illuminance of light incident from the first direction is the first threshold or more.

Certain aspects pertain to a cloud detector comprising a first detector module directed to a first region of the sky and a second detector module directed to a second region of the sky. Each detector module has a tube enclosing one or more sensing elements. The one or more sensing elements of the first detector module are configured to take weather condition readings from the first region of the sky. The one or more sensing elements of the second detector module are configured to take weather condition readings from the second region of the sky. In one aspect, the cloud detector is configured to detect cloud cover based on these weather condition readings. In some cases, the one or more sensing elements comprise an infrared radiation detector (e.g., thermopile) for measuring infrared radiation intensity and a photosensor element for measuring sunlight intensity.

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.

An optical parameter measurement device and a corresponding method are provided. A light beam from a to-be-tested display panel is split by a beam-splitting assembly into at least two testing light beams. A voltage value corresponding to a first testing light beam is measured by a trans-impedance amplification circuit corresponding to a first optical sensor. Next, an integration time period is determined by a control circuit according to voltage values from the trans-impedance amplification circuit and a predetermined relational model between voltage values corresponding to the light intensities and integration time periods. A voltage value corresponding to a second testing light beam is finely measured by the integration circuit corresponding to a second optical sensor within the integration time period. Finally, the display brightness value of the to-be-tested display panel is determined by the control circuit according to a voltage value from the integration circuit within the integration time period.

An optical sensor (10) includes a first switch (SW1) and a second switch (SW2), these switches are switched between a first step and a second step and thus the coupling of light receiving portions (photodiodes) and three analog-to-digital converters (ADCs) is switched. In the first step of the switch, photocurrents generated in a blue light receiving portion (BLUE), a green light receiving portion (GREEN) and a red light receiving portion (RED) are processed in real time. In the second step, photocurrents generated in an infrared light receiving portion (Ir), an environmental light receiving portion (CLEAR) and the green light receiving portion (GREEN) are processed. The photocurrents of the infrared light receiving portion (Ir) and the environmental light receiving portion (CLEAR) generated in the first step are calculated from a ratio of the two photocurrents measured in the green light receiving portion (GREEN).