A fast laser diode of OSRAM Opto Semiconductors provides light for the new 3D camera of the Swedish manufacturer FOTONIC. The component has been developed specially for 3D cameras like the FOTONIC C70. It facilitates range finding for moving object with good depth resolution at video rate.
OSRAM Opto Semiconductors‘ new infrared laser diode provides high optical power of about 0.5 Watt, even when in continuous wave operation. With a wavelength of about 845 nanometers the light is hardly visible to the human eye, and yet it is well within the sensibility range of the camera chip.
Three-dimensional cameras superimpose a two-dimensional picture with information on the range and surface profile of an object. Industrial applications for such systems are, for example, the gauging of fluid levels or the grading of objects according to size or shape. Three-dimensional sensors also provide reliable stereoscopic information, e.g. for the control of robot arms.
Fast Modulation yields high resolution
The camera FOTONIC C70 is based on a CMOS sensor and it makes use of the principle of time-of-flight measurement. A laser diode, which is integrated into the camera, transmits a light pulse which the target reflects back. Each of the 120×160 pixels of the camera chip records the distance to the object by measuring a respective phase shift compared to the emitted light pulse. The precision of this distance measurement and the range of the sensor increases with the modulating frequency of the light source. Due to their fast switching times of only a few nanoseconds, laser diodes are particularly well suited for this application. The laser diode, developed for this kind of 3D cameras is modulated with 44 MHz. Within the range of 0.1 to 7 meter, the camera measures distances with an accuracy of 3 up to 30 millimeter. For OSRAM Opto Semiconductors it is the first application of a laser diode in a 3D sensor of this type. Rickard Åström of FOTONIC is convinced of the laser’s performance: “Together with OSRAM we’ve managed to increase the performance of our FOTONIC C70 Camera. We plan to use this component in future generations of our camera.”
Dr. Jörg Heerlein, marketing manager for pulsed laser diodes at OSRAM Opto Semiconductors, predicts a growing market for such applications: “In industry, three-dimensional sensor technology is on the advance. This technology is becoming interesting for the consumer market and the automobile sector, too. To name a few applications, it is used for touch screens, or in sensors for accident avoidance systems in automobiles. We therefore designed this new laser diode specially for 3D sensor technology.” The sturdy metal package of the component meets the demands for industrial applications. OSRAM Opto Semiconductors will present the laser together with the FOTONIC C70 3D camera at the Measurement Fair Sensor+Test 2011 in Nuremberg at the beginning of June.
The 3D camera FOTONIC C70 produces relief images which yield the distance between object and camera for each pixel. Fast and powerful light sources like the new pulsed laser diode of OSRAM Opto Semiconductors facilitate particularly precise range finding.