Compact proximity sensor contributes to greater miniaturisation and battery capacity

ROHM has created a compact 2mm × 1mm proximity sensor, the RPR-0720, optimised for applications needing attachment/detachment and proximity detection.

As the use of IoT continues to grow, sensor devices that play a crucial role are demanding greater miniaturisation and functionality. The company provides a lineup of proximity sensors that incorporate light-emitting and receiving elements in a single package, supplying unmatched versatility that has led to widespread adoption in various applications, from mobile devices to industrial equipment. Mainly for wearable devices, in response to the increasing demand for small proximity sensors that can support enhanced designs and an increase in the number of parts resulting from higher functionality, the company developed a compact proximity sensor that combines a VCSEL and sensor IC.

The device is an optical sensor module that adopts a VCSEL supplying higher directivity than LEDs as the light-emitting element and a sensor IC for the light-receiving element. Compact size is accomplished by optimising the module structure utilising in-house chips, decreasing area by approximately 78% compared to conventional products. At the same time, the wide input voltage range (2.7V to 4.5V) of the built-in VCSEL removes the necessity for a peripheral voltage booster circuit (i.e. consisting of a power supply IC, three capacitors, and one inductor) when employing a Li-ion battery, contributing to greater space savings that leads to smaller applications and improved battery capacity. This makes it ideal for sensing attachment/detachment and detecting assorted conditions in a wide range of applications.

The device is suitable for a wide range of applications that use light reflection to detect conditions; attachment/detachment detection of wireless earbuds, smart watches, gaming console controllers, VR headsets, and the like paper detection in printers, copiers, shredders, and other office automation devices; e-cigarette cartridge/liquid detection; detecting various conditions in smartphones and laptops.

The company also offers an evaluation board for the compact proximity sensor (RPR-0720-EVK).