Proximity Sensor
A device that senses when another object is close by.
In a mobile phone, a proximity sensor is most commonly used to detect when the phone is held to the face. Specifically, the sensor detects human skin within a certain distance. The sensor is typically placed next to the speaker area at the top of the phone.
The phone uses this information to temporarily power down the display - to save battery life - and the touch screen, to prevent the face from accidentally touching on-screen buttons and triggering unwanted actions.
There are multiple types of proximity sensors, employing different technology. One type projects an invisible beam of infrared light and measures the beam's reflection from nearby surfaces. Another type uses capacitive technology (like touch-screens) that uses an electric field to detect the unique electrical properties of human skin.
Some types of proximity sensors detect any type of solid object, while other types are tuned specifically for one material, such as human skin.
Last updated Jan 22, 2022 by Rich Brome
Editor in Chief Rich became fascinated with cell phones in 1999, creating mobile web sites for phones with tiny black-and-white displays and obsessing over new phone models. Realizing a need for better info about phones, he started Phone Scoop in 2001, and has been helming the site ever since. Rich has spent two decades researching and covering every detail of the phone industry, traveling the world to tour factories, interview CEOs, and get every last spec and photo Phone Scoop readers have come to expect. As an industry veteran, Rich is a respected voice on phone technology of the past, present, and future.
