Aug 1 2006
Osram Opto Semiconductors has developed a new sensor that automatically adjusts a monitor display’s brightness to that of the ambient light. What’s special about the new ambient light sensor is that it is the first such system to exactly duplicate the range of sensitivity of the human eye, which makes it possible to adjust the brightness of displays even more precisely in accordance with changing light conditions. And this means the sensor can help to prevent eye fatigue suffered by users of laptops and PCs, a problem that can quickly arise when working with bright displays in dark surroundings.
The human eye is most sensitive to light at a wavelength of 560 nanometers, which appears as a greenish yellow. And it is exactly in this color range that the SFH 5711 sensor is most sensitive — thanks to a new semiconductor material that’s been patented by Osram, a Siemens subsidiary. Until now, sensors of this type have used silicon.
The new sensor will be launched on the market in the fall. Only a few millimeters in diameter and with a supply voltage of 2.3 to five volts, the sensor is ideally suited for use in mobile devices and automobiles. Not only does the new sensor make cell phone displays more clearly visible in bright surroundings, it also prolongs the life of batteries because the display lighting only operates at full power when necessary. The sensor can distinguish the level of brightness over a vast range, from an illuminated street at night to daylight.
As a result, a computer display can automatically adjust its brightness in accordance with changing light throughout the day. For example, the display would be brighter in the midday sun than on a dim winter afternoon. In addition to the changes in brightness during the course of a day, other settings are also possible. For example, the sensor can be used in car headlights in a manner completely opposite to that just described: The sensor measures the brightness of the ambient light and automatically turns on a vehicle’s headlights when it enters a tunnel, for example, or at dusk.