Lightproof goniophotometer for small LED modules

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Precise determination of the color temperature of white LEDs

The LEDGON goniophotometer from Instrument Systems determines the angle-dependent spatial radiation properties of LEDs and small LED modules. The entire hemisphere in the direction of radiation of the LED can be measured. Thanks to the high angle resolution of 0.1° exact readings can be obtained for narrow-angled LEDs.

In combination with the CAS 140D spectroradiometer, spectral parameters, e.g. angle-dependent color coordinates or color temperature, can also be measured. This is particularly important for white LEDs, as the color temperature can vary considerably, depending on the beam angle.

The LEDGON is suitable for samples with a diameter of up to 112 mm and a weight of 700 g.

Highly precise measurement of luminous flux and radiant power

The LEDGON goniophotometer is mainly used for precise determination of radiant power or luminous flux. Measurement errors in a set-up with integrating spheres due to the geometry of the latter do not occur. Instrument Systems has developed the appropriate modules for the SpecWin Pro software, with which luminous flux can be measured fully automatically and conveniently.

Examples of applications

LEDGON 100 – Technical data



Angle range

θ axis: ca. +/- 100°; Φ axis: 360°

Angle accuracy

θ axis: 0.1°; Φ axis: 1°

Sample dimensions max.

112 x 112 x 48 mm3 (W x L x H)

Sample weight max.

700 g

The instrument incorporates an optical rail with two permanently mounted rotation stages for the angles phi and theta. The rotation stage for phi has a hollow shaft into which LED test sockets from Instrument Systems (all except LED-850) can be inserted. At the other end of the optical rail is an optical probe that can be positioned at a distance of 5 to 70 cm from the LED.

The entire set-up is contained in a lightproof housing with a hinged cover.