Apple supplier Ams has developed a light and infrared proximity sensor that can sit behind a smartphone’s screen, reducing the area required to house such sensors to allow for a larger screen size.
Currently, sensors are typically located on front-facing bezels, the area at the top of a smartphone display that does not expand.
By developing a ‘Behind OLED’ ambient light/proximity sensor (the TCS3701) , Ams enables smartphone manufacturers to achieve the highest possible ratio of display area to body size while retaining touchscreen disablement and automatic display brightness/colour adjustment functions, which require an RGB/infrared light sensor.
Despite the constraint of operating behind an emissive OLED display screen, the TCS3701 senses the addition of the ambient light passing through the display to light emitted by the display’s pixels located just above the sensor. Measurement algorithms are used to detect ambient light levels without knowledge of the display pixel brightness above the sensor. The sensor is housed in a 2.0mm x 2.5mm x 0.5mm OQFN package.
Despite the opacity of an OLED screen, Ams said the sensor can still produce accurate light measurements in all lighting conditions.
‘Smartphone OEMs today are striving to maximise their products’ screen-to-body ratio, reducing the bezel area as much as possible on the display’s face,’ said David Moon, senior marketing manager at Ams. ‘The TCS3701 enables phone designers to take this trend to a new level.’
