Ambient light sensors enable light-based solutions to automatically adapt to the ambient conditions and thereby not only ensuring ideal visibility but also high energy efficiency. After introducing the latest ambient light sensors product line for automotive interior applications Osram Opto Semiconductors has now added a new solution ideally suited for smart street lighting and consumer applications. A street light application example with the new SFH 5701 will be presented at electronica 2018 in Munich.
Category: Street & Urban
Location: Regensburg, Germany
Technology/Services: Photo IC
The majority of the latest generation of industrial and home automation applications with a display using ambient light sensors (ALS) to improve the user experience as well as to optimize the overall system power. Other applications require ambient light sensors to modulate a light source or trigger other product features. Many of these applications are stand-alone systems and require high quality but cost effective and easy to implement ambient light sensors. Analog ambient light sensors are a perfect fit for such use cases.
An application example that demonstrated the benefits of analog ALS is the use in smart street lighting. Until recently, there has been little that local governments could do to reduce the cost of road lighting. It is an absolute essential element in keeping road users and pedestrians safe at any hour of the day. The utilization of LED technology has already provided a very attractive alternative to traditional lighting – one that is both highly energy-efficient and meets international regulation for brightness. Sensor technology now adds an intelligent way to adapt street lighting automatically to the ambient conditions. In opposite to traditional timers for street lighting the detectors can identify the exact ambient light independently from the time. Therefore if it is a foggy day or an early night fall the brightness will automatically be increased while it will be decreased whenever the ambient light is brighter to make sure only the necessary minimum of energy will be used.
The SFH 5701 analog ambient light sensor is Osram Opto Semiconductors’ latest addition to its comprehensive sensor portfolio. The ALS is an active component in which the IC is powered by the signal current and is therefore not reliant on an external power supply. It therefore features only two pins instead of three or more – making it much easier to connect and operate.
The sensor is an analog component with a linear integrated amplifier which supplies a typical signal of 135 µA at 100 lux. The combined high dynamic range and high sensitivity at low illuminance of 0.01 lux produce reliable light measurements for a wide range of ambient light conditions. With a footprint of just 1.25 mm x 2.0 mm x 0.8 mm the surface-mountable component is also extremely compact. Integrated thermal compensation makes the component insensitive to temperature fluctuations and thereby eliminating temperature based false reading, which is important in many applications fields including outdoor lighting.
The special filter encapsulation of the SFH 5701 allows mainly green light to penetrate and filters out infrared wavelengths very efficiently. This ensures that the sensor is ideally adapted to the spectral sensitivity of the human eye, which also is most sensitive to light in the green range of the color spectrum. Overall, the sensor detects light in the spectrum between 450 nm and 700 nm – the visible range for the human eye.
In addition to smart street lighting the ALS solutions can also be used for various display and consumer applications as well as for home automation. The product line of ALS with the same footprint also offers products specifically qualified and certified for industrial (SFH 5701) as well as for automotive applications (SFH 5701- A01).