Macnica Inc. exhibited an ultraviolet sensor, no bigger than grain of rice, at the Embedded Systems Expo & Conference (ESEC), which opened in Tokyo on July 9, 2003.
The sensor is a surface-mount type, measuring 2.54mm x 2.0mm x 1.1mm. It is “possibly the world’s smallest” ultraviolet sensor responding only to UV-A and UV-B waves, according to Macnica.
The sensor is sensitive to a wavelength range of 270nm to 410nm (UV-A and UV-B waves). Having almost no sensitivity to visible light, it does not work as an illumination sensor.
In the demo, an evaluation board was connected to a mockup of a mobile phone containing an embedded UV sensor. Macnica demonstrated an application that produced an animated image of a growing sprout on the evaluation board’s LCD panel when the phone was exposed to UV light.