February 9, 2021 by Gina Roos
Targeting edge-to-edge smartphone displays, the TSL2520 and TSL2521 ambient light sensors from ams fit in a tiny bezel or gap between the display screen and the chassis of the smartphone to enable the screen to stretch from edge-to-edge of the chassis with no aperture. This enables smartphone manufacturers to maximize the viewable screen area while enabling camera image correction, said ams.
The ams TSL2520 ambient light sensor (ALS) features four photodiodes for visible light sensing and two infrared photodiodes, which allows for rejection of IR interference and produces accurate measurements of ambient light intensity (lux). The photodiodes are placed at the end of the sensor’s 2 x 1 x 0.5 mm package, so the device can be positioned at the gap between the display screen and the chassis of the phone to maximize the screen-to-body ratio.
The TSL2521 provides the same ALS function and identical mechanical specifications as the TSL2520 but adds flicker detection capability. Sensing flicker in artificial light sources such as LEDs at frequencies up to 7 kHz, the TSL2521 provides an image correction input to the phone’s camera. This allows the camera to eliminate banding and other flicker-generated artefacts that can distort captured images and videos, said the company.
Operating from a 1.8-V supply and featuring configurable sleep modes, the TSL2520/21 sensors offer low power consumption to extend the run time of the phone’s battery. They also offer accuracy and high sensitivity measuring ambient light levels down to 1 mlux. The sensors can operate under any glass types and inks with any degree of light attenuation without requiring a visible aperture in the display glass, according to ams. Samples are available for both devices.
Also aimed at maximizing the screen-to-body ratio for a wider viewable display area, ams recently introduced the TCS3410 combined ambient light/RGB color and flicker detection sensor that measures 2 x 1 mm with a 0.5-mm height. Targeting bezel-less and ultra-narrow bezel smartphones, the low-profile makes it easy to fit in waterdrop notch designs used in selfie cameras or in the ultra-narrow bezel of a smartphone.