High Power Emitters for Illumination Applications0 pages

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Application Note

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More and more applications are using

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invisible infrared (IR) light sources with high

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optical output power levels in the range of

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Watts. This paper focuses on the benefits

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using high power infrared products and their

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special requirements in the application.

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In general high power emitters can be driven

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with DC currents in the range of 1 Ampere

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whereas most low power products like 5 mm

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Radiais are limited to 100 mA.

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As the light output increases with driving

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current the optical power is raised by a

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factor of ten compared to standard devices.

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At the same time much less board space is

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occupied as fewer devices are needed. On

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the other hand a careful thermal

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management is absolutely mandatory

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because the thermal power dissipation is

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increasing in the same way as the optical

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output power. To keep the junction

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temperature of the chip as low as possible a

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low thermal resistance is needed and the

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standard FR4-PCB has to be replaced by a

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metal core PCB. Like this a high optical

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efficiency of the IRED can be achieved.

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High power emitters as infrared light sources

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are used in:

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Closed-circuit television (CCTV)

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Biometrie access control systems

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Machine vision systems

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Automatic number plate recognition

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(AN PR)

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Camera based distance systems

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3D-cameras (gesture recognition,

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play tables)

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3DTV (data transmission to shutter

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glasses)

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Night Vision

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Sensing systems (pre-crash)

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Driver monitoring

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Ptjllnum Diagcn

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SFH 4m

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S F hi 423$

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OSTAR Lighting

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SFH 47M

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5FH 4751

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High power product overview.

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In Figure 1 the OSRAM IR high power

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product portfolio is presented. A product

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selection guide with the main optical

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parameters is shown in Table 1 (see

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Chapter 4).

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In general two common wavelengths

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(850 nm and 940 nm) are available. The

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spectral emission range matches well to the

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sensitivity range of standard photo diodes,

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photo transistors or CCD and CMOS

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cameras with extended IR sensitivity.

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The available Diamond Dragons with

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integrated ±20° silicone lens provide a

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narrower beam compared to the Platinum

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Dragons with ±60°. The focussed beam

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allows an irradiation of objects at higher

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distances. The OSLON is in between with

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±45°.

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For applications where space is very limited

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the 850 nm double stacked emitters

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(SFH 4235, SFH 4715S), where two

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vertically stacked pn-junctions are used in

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one chip, are the right choice. These devices

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September, 2011

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Page 1 of 10

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OSRAM

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Opto Semiconductors

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