A method of proximity sensing which comprises emitting light from an emitter and detecting reflected light, applying an offset to the detected reflected light to provide an output signal indicative of proximity, determining an average signal of the output signal; determining whether drift has occurred by comparing the output signal to a first threshold and comparing the average signal to a different threshold, and adjusting the offset if drift is identified.

An apparatus comprises a display screen, and an optical sensor module which is disposed behind the display screen. The optical sensor module further comprises a light emitter operable to generate light having a wavelength for transmission through the display screen toward a target object. A light sensor is operable to sense light reflected by the target object and having the wavelength. A reducer is arranged for reducing the optical power density by increasing a diameter of a light beam generated by the light emitter on the display screen, wherein the reducer is disposed between the light emitter and the display screen so as to intersect the light beam generated by the light emitter.

This invention provides an earphone with a low light transmittance and a non-porous sensor cover. Covering the sensing cover on the proximity sensing device can reduce the interference of most of the ambient light and improve measurement accuracy.

A color temperature switching scheme for an LED lighting device is disclosed. The color temperature switching scheme comprises a plurality of different color temperature performances correspondingly generated by a plurality of different paired combinations of a first electric power allocated to a first LED load emitting a light with a first color temperature and a second electric power allocated to a second LED load emitting a light with a second color temperature such that a mingled color temperature between the first color temperature and the second color temperature can be generated thru a light diffuser. For tuning the mingled color temperature of the LED lighting device a reverse yet complementary power adjustment process for distributing a total electric power T between the first LED circuit and the second LED circuit is required such that a total light intensity remains unchanged while the mingled color temperature is being adjusted.

A color temperature switching scheme for an LED lighting device is disclosed. The color temperature switching scheme comprises a plurality of different color temperature performances correspondingly generated by a plurality of different paired combinations of a first electric power allocated to a first LED load emitting a light with a first color temperature and a second electric power allocated to a second LED load emitting a light with a second color temperature such that a mingled color temperature between the first color temperature and the second color temperature can be generated thru a light diffuser. For tuning the mingled color temperature of the LED lighting device a reverse yet complementary power adjustment process for distributing a total electric power T between the first LED circuit and the second LED circuit is required such that a total light intensity remains unchanged while the mingled color temperature is being adjusted.

Methods, systems, and devices for wearing detection are described. A method may include directing light from a light source to a detector using an optical light guide of the wearable device, where the optical light guide includes an optical interface configured to allow at least a portion of the directed light to escape the optical light guide based on a refractive property of a material contacting the optical interface. The method may include measuring, via the detector, an amount of escaped light which escaped the optical light guide, where the amount of escaped light is indicative of a level of surface contact at the optical interface of the optical light guide. The method may further include controlling an activation of one or more sensors of the wearable device based on the amount of escaped light.

A theory and a technical foundation for building a technical framework of a color temperature tuning technology are disclosed, composing a power allocation algorithm and a power allocation circuitry, wherein the power allocation algorithm is a software for designing a process of dividing and sharing a total electric power between at least a first LED load emitting light with a first color temperature CT1 and a second LED load emitting light with a second color temperature CT2 to generate at least one paired combination of a first electric power X allocated to the first LED load and a second electric power Y allocated to the second LED load to create at least one mingled light color temperature CTapp thru a light diffuser according to color temperature tuning formulas CTapp=CT1.Math.X/(X+Y)+CT2.Math.Y/(X+Y) and X+Y=constant; and the power allocation circuitry is a hardware designed for implementing the process.

The present invention provides a proximity sensing device, which comprises an ambient light calibration digital-to-analog converter and at least one crosstalk calibration digital-to-analog converters. The proximity sensing device is able to quickly generate calibration parameters for the interference caused by the ambient list and crosstalk caused by different reflection, to calibrate the sensed signals to avoid wrong judgments.

An apparatus includes a display screen, and an optical proximity sensor module disposed behind the display screen. The optical proximity sensor module includes a light emitter operable to produce light having a wavelength for transmission through the display screen toward a target object, and a light sensor operable to sense light reflected by the target object and having the wavelength. The optical proximity sensor module can includes means for reducing a maximum energy density of a light beam produced by the light emitter. The means for reducing the maximum energy density of the light beam is disposed between the light emitter and the display screen so as to intersect the light beam produced by the light emitter. In some cases, there are multiple light emitters collectively operable to provide sufficient optical energy for proximity sensing without producing a visible spot on the display screen. These and other techniques can help reduce or eliminate display screen distortion caused by energy from the light emitters.

A proximity sensor (1) with crosstalk compensation comprises a transmitting circuit (10) to transmit a signal to be reflected at a target (2) and a disturbing object (3), and a receiving circuit (20) to receive a reflected signal (RS) having a useful component (RSI) and a noise component (RS2). The receiving circuit (20) comprises an output node (A20) to provide an output signal (Vout2) in dependence from the distance of the proximity sensor (1) from the target (2). The receiving circuit (20) comprises a crosstalk compensation circuit (100) comprising a first charging circuit (110) to provide a first charge for for coarse crosstalk compensation and a second charging circuit (120) to provide a second charge for fine crosstalk compensation. A control circuit (30) sets an amount of the first and the second charge so that the output signal (Vout2) of the crosstalk compensation circuit (100) is dependent on the useful component (RSI) and independent on the noise component (RS2) of the reflected signal (RS).