OLED based touch sensing and user identification

A touch screen, comprising:

• a plurality of light emitting diodes (LEDs) configured to emit a first light for displaying one or more images, the plurality of LEDs including first LEDs and second LEDs, the first LEDs configured to emit a second light for optical touch sensing, the second light being a predetermined light different from and independent from the one or more images displayed with the first light, and the second LEDs configured to sense at least a portion of a reflection of the second light and generate one or more signals indicative of the reflection of the second light;
• a plurality of current sources coupled to the plurality of LEDs;
• sense circuitry coupled to the second LEDs;
• a switch configured to electrically couple and decouple the second LEDs to the sense circuitry during a touch sensing mode;
• and
• a processor configured to:
• receive the one or more signals generated by the second LEDs, and
• determine one or more properties of one or more proximate objects based on the one or more signals.