Why is the smartphone screen always off when you listen to the phone?

If you notice you will see, every time a call comes in, you press the player button and put the phone close to your ear to listen, the smartphone screen immediately turns off automatically.

The fact that the smartphone screen turns off when we listen to the phone not only helps to prevent a part of the body (such as the ear) from touching the screen and disrupting the call but also saves the device's battery .

So, why can smartphones do this completely automatically? That's thanks to a sensor called Proximity Sensors, which is usually placed on the front of the smartphone, near the camera area or speaker that detects when things get close to the sensor.

Proximity sensor emits a type of electromagnetic field, a type of light (such as infrared light) or a beam of radiation. Based on the field or return signals, the proximity sensor determines whether the smartphone is near your body (listening to the phone) to respond accordingly.

The operating range of proximity sensors on smartphones is about 2cm to 5cm. In addition, there are many other proximity sensors used in industry that can detect objects at a longer distance.

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