The new TCS3720, the next generation of ams OSRAM’s ‘behind OLED’ sensors, is intended for use with smartphone display screens which operate at a high refresh rate with high-frequency PWM brightness control, and which have low transmissivity. These display features create extremely challenging operating conditions for a behind OLED ALS/proximity sensor: high speed shortens the blanking time in which the device can measure optical signals, while low transmissivity attenuates the signal reaching the sensor’s photodiodes.

ams OSRAM innovations in the TCS3720 have produced greatly increased sensitivity and dynamic range compared to earlier generations of behind OLED sensors. The TCS3720 achieves more than five times the sensitivity of the first-generation TCS3701, and a three times higher signal-to-noise ratio (SNR). The TCS3720 is supplied in a 3.34mm x 1.36mm x 0.6mm 12-pin OLGA package.

ams OSRAM has also introduced independent VSYNC timing of the ALS and proximity sensing functions to give improved centering of measurement operations in the blanking window.

The outcome of these innovations is accurate measurement performance even when operating behind a faster, darker OLED screen. In typical implementations, the TCS3720 can reliably support a proximity sensing range of up to 5cm, while providing color and illuminance measurements for granular optimization of the phone display’s brightness and color balance.

“Today’s smartphone provides an amazing display experience, offering silky smooth rendering of dynamic action scenes in high resolution. With the launch of the TCS3720, smartphone manufacturers can meet customers’ expectations for superlative display performance without compromising display management or proximity sensing function,” said Will Zhou, director of product marketing for integrated optical sensors at ams OSRAM.

The TCS3720 is a fully integrated ALS and proximity sensor IC. It includes:

Two advanced drivers for infrared proximity sensing VCSELs
Red, green, blue and clear photodiode channels with built-in ultraviolet and infrared blocking interference filters
Self-maximizing dynamic range
Advanced cross-talk cancellation
Adjustable infrared emitter timing and power output to permit optimization for SNR or power consumption

The TCS3720 is in volume production now. For more information on the sensor go to https://ams.com/tcs3720 and for more information on the evaluation kit to https://ams.com/tcs3720-eval-kit.

TCS3720 from ams OSRAM offers higher sensitivity and higher signal-to-noise ratio to maintain measurement performance when operating behind new low-transmissivity screens
Image: ams

New ALS/proximity sensor from ams OSRAM enables accurate color and brightness management of latest smartphones’ high-speed, high-definition OLED displays
Image: OSRAM