Extended Detection Range With VCNL Family of Proximity Sensors

Vishay's VCNL4010, VCNL4020, and VCNL3020 proximity  sensors each combine an infrared emitter, PIN photodiode, and signal processing IC  in a single package with a 16-bit ADC. With a range of up to 20 cm (7.9 in), these stand-alone, single-component solutions greatly simplify the use and design-in of proximity  sensors in consumer and industrial applications. This application note will explore extending the range of these devices even further using external infrared emitting diodes (IRED) and drivers. In addition, mechanical design considerations will be discussed.
http://www.vishay.com/doc?84225