High Power Emitters for Illumination Applications0 pages
Application Note
nnnnMore and more applications are using
nnnninvisible infrared (IR) light sources with high
nnnnoptical output power levels in the range of
nnnnWatts. This paper focuses on the benefits
nnnnusing high power infrared products and their
nnnnspecial requirements in the application.
nnnnIn general high power emitters can be driven
nnnnwith DC currents in the range of 1 Ampere
nnnnwhereas most low power products like 5 mm
nnnnRadiais are limited to 100 mA.
nnnnAs the light output increases with driving
nnnncurrent the optical power is raised by a
nnnnfactor of ten compared to standard devices.
nnnnAt the same time much less board space is
nnnnoccupied as fewer devices are needed. On
nnnnthe other hand a careful thermal
nnnnmanagement is absolutely mandatory
nnnnbecause the thermal power dissipation is
nnnnincreasing in the same way as the optical
nnnnoutput power. To keep the junction
nnnntemperature of the chip as low as possible a
nnnnlow thermal resistance is needed and the
nnnnstandard FR4-PCB has to be replaced by a
nnnnmetal core PCB. Like this a high optical
nnnnefficiency of the IRED can be achieved.
nnnnHigh power emitters as infrared light sources
nnnnare used in:
nnnnClosed-circuit television (CCTV)
nnnnBiometrie access control systems
nnnnMachine vision systems
nnnnAutomatic number plate recognition
nnnn(AN PR)
nnnnCamera based distance systems
nnnn3D-cameras (gesture recognition,
nnnnplay tables)
nnnn3DTV (data transmission to shutter
nnnnglasses)
nnnnNight Vision
nnnnSensing systems (pre-crash)
nnnnDriver monitoring
nnnnPtjllnum Diagcn
nnnnSFH 4m
nnnnS F hi 423$
nnnnOSTAR Lighting
nnnnSFH 47M
nnnn5FH 4751
nnnnHigh power product overview.
nnnnIn Figure 1 the OSRAM IR high power
nnnnproduct portfolio is presented. A product
nnnnselection guide with the main optical
nnnnparameters is shown in Table 1 (see
nnnnChapter 4).
nnnnIn general two common wavelengths
nnnn(850 nm and 940 nm) are available. The
nnnnspectral emission range matches well to the
nnnnsensitivity range of standard photo diodes,
nnnnphoto transistors or CCD and CMOS
nnnncameras with extended IR sensitivity.
nnnnThe available Diamond Dragons with
nnnnintegrated ±20° silicone lens provide a
nnnnnarrower beam compared to the Platinum
nnnnDragons with ±60°. The focussed beam
nnnnallows an irradiation of objects at higher
nnnndistances. The OSLON is in between with
nnnn±45°.
nnnnFor applications where space is very limited
nnnnthe 850 nm double stacked emitters
nnnn(SFH 4235, SFH 4715S), where two
nnnnvertically stacked pn-junctions are used in
nnnnone chip, are the right choice. These devices
nnnnSeptember, 2011
nnnnPage 1 of 10
nnnnOSRAM
nnnnOpto Semiconductors
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