Providing drivers with perfectly illuminated roads: a compact brightness sensor for headlamp control.
Osram introduces a new photodiode with ambient light sensitivity for automotive applications
Osram Opto Semiconductors expands its ambient light sensor portfolio to address automotive applications challenged by strict limitations with respect to cost or size. The new photodiode SFH 2716 A01 combines a good technical performance and a small package in the most economic way. Typical applications include headlamp control or automatic dimming of dashboard backlighting.
The SFH 2716 A01 offers the same ambient light sensing characteristics as the large area photodiode SFH 2430 commonly used in automotive applications. Its spectral sensitivity is considerably reduced in the infrared wavelength range and reaches a maximum at 570 nanometers (nm). The sensor is thus adjusted closely to the spectral sensitivity of human eyes, known as V-Lambda, and measures ambient light conditions in a way that matches human perception. Ambient light sensors like these are used in vehicles to automatically dim instruments and dashboard backlights to ensure reliable visibility under all conditions. Automatic headlamp control is another application that ensures additional safety especially at twilight or when entering tunnels. In this case, the photodiode is integrated into the rain sensor that is attached to the inner surface of the windshield.
Small chip brings down cost and size
In some cases, both these applications may benefit from a more compact and economic variant of the SFH 2430. To bring down cost and size, the SFH 2716 A01 has a tiny chip with an active area of 0.348 mm2. As a consequence, its sensitivity is lower and thus yields a photocurrent of 57 microampere (μA) at a brightness of 100 lux (lx). The chip is mounted in a compact Chipled package measuring only (2 x 1.25 x 0.8) mm and the new photodiode is qualified for automotive applications.