Unlocking and working principle of distance sensor

I remember when I used my mobile phone before Bian Xiao, I often accidentally hung up on other people's phones. Sometimes when I'm holding the phone in my hand, I suddenly hear someone hello, hello, hello. When I was in my pocket, I accidentally bumped into someone else's phone or accidentally sent some messy information to others, which led to so many jokes without knowing it. This is all because the distance sensor is unlocked.

principle of operation

Distance sensors, also known as displacement sensors, are generally located on both sides of the receiver or in the receiver groove to facilitate its work. When the user answers or makes a call, he holds the mobile phone close to his head. When the distance sensor can measure a certain distance, he informs the screen background light to turn off, and then lights it after taking it away, which is more convenient for users to operate and saves electricity.

A machine that detects the physical changes of an object through various elements and measures the distance displacement from the sensor to the object by converting the changes into distances. According to the different components used, it can be divided into optical displacement sensor, linear proximity sensor and ultrasonic displacement sensor. The distance sensor used in mobile phone is a kind of sensor that measures distance by measuring time.

The infrared pulse sensor emits a very short light pulse, and measures the time from emission to object reflection, and calculates the distance from the object by measuring the time.

Calculation method

Light emitted by light source of optical displacement sensor (intelligent sensor ZX-L-N series, etc.). ) is condensed by a lens and irradiated on an object. The reflected light emitted by an object is focused on a one-dimensional position detection element (PSD)* through a light receiving lens. If the position of the object (the distance from the tester) changes, the imaging position on PSD will be different; If the two output balances of PSD change, the imaging position on PSD will be different, and the two output balances of PSD will change again. If these two outputs are taken as A and B respectively, and A/(A+B) is calculated, plus appropriate pulling coefficient' K' and residual' C', the formula can be obtained as follows: displacement = A/(A+B)+K+C. The measured value is not the illuminance (brightness), but the displacement of the two outputs A and B. Therefore, even if the measured object and the measured object

Application in life

Nowadays, distance sensors are widely used in mobile phones: when the mobile phone is connected, if the distance sensor (an inconspicuous small rectangle between the auxiliary camera and the light sensor) is blocked, the screen will turn black. That is, when you answer the phone, the screen will turn black, saving electricity and preventing misoperation.

Now many smart phones also have this. When the sensor is close to the skin, the touch screen will fail, mainly to prevent the human face from misoperation of the touch screen, which is still very useful on the touch screen.

Is the distance sensor very powerful? Unlocking with the distance sensor can not only reduce misunderstandings in life, but also reduce the misoperation of the mobile phone, which is more humanized. Nowadays, mobile phones are basically touch screens, and distance sensors are well used in mobile phones. I used to think it would be nice to have a mobile phone. I didn't expect that smart phones have become very common in just a few years, and mobile phones will definitely continue to develop. I believe that in a few years, the mobile phone can get rid of the limitation of the screen and become more perfect, and the distance sensor will definitely play a greater role.

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