Optical sensing apparatus and operating method thereof

Abstract

An optical sensing apparatus and an operating method thereof are disclosed, and the apparatus includes a sensing unit, an analog / digital conversion unit, a switching unit, a first processing unit, and a second processing unit. The sensing unit provides a light sensing signal. The analog / digital conversion unit is coupled to sensing unit and converts light sensing signal into a digital light sensing signal. The switching unit is coupled to analog / digital conversion unit and selectively switched to a first mode or a second mode according to a mode control signal. The first processing unit and second processing unit are coupled to analog / digital conversion unit and switching unit. When switching unit is switched to first mode according to mode control signal, first processing unit generates a photoplethysmography (PPG) signal according to digital light sensing signal; when switching unit is switched to second mode according to mode control signal, second processing unit generates a proximity sensing signal according to digital light sensing signal.

Description

technical field [0001] The present invention relates to optical sensing, in particular to an optical sensing device capable of both proximity sensing and heart rate sensing and its operating method. Background technique [0002] Because the hemoglobin in the blood is light-absorbing, and the pulse formed by the arterial rhythm will cause the change of the thickness of the arterial blood vessel, which will also change the blood content in the blood vessel. Therefore, the traditional optical sensor can use a light volume change Tracing (Photoplethysmography, PPG) technology to sense blood vessel pulse heart rate. The principle is: use a group of light sources to send light beams through the skin of the area to be tested and inject them into the artery, and use a group of photosensors corresponding to the wavelength of light on the opposite side (penetrating) or at the same time of the area to be tested. Side (reflective) for intensity sensing of transmitted or reflected light...

AI Technical Summary

Problems solved by technology

However, since the filtering frequency of this high-pass filter is usually set at about 0.5Hz, it must be composed of capacitors with high capacitance values ​​in circuit implementation

Whether using external or built-in capacitors, the overall volume and cost of the optical sensor will increase, which is not conducive to its application in portable and wearable electronic devices

In addition, the range of motion noise that this high-pass filter can withstand is also limited to a certain extent, and it cannot be dynamically adjusted in response to different motion noises.

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