The LEDGON goniophotometer from Instrument Systems determines the spatial radiation pattern of LEDs and small LED modules. Measurement is made over the whole forward hemisphere of an emitting LED. A high angle resolution of 0.1° means exact measurements even for narrow emission angle LEDs. In combination with the CAS 140CT spectroradiometer, additional spectral parameters, such as the angle dependence of color coordinates or color temperature, can also be measured. White LEDs, for example, exhibit a significant angle dependence of the color temperature.
Exact measurements of luminous flux and total radiant power
The LEDGON goniophotometer can also be used for accurate determination of luminous flux and total radiant power. The measurement errors typical of integrating spheres (due to their geometry) are avoided. Instrument Systems has developed an appropriate add-on for the SpecWin Pro software that fully automates the measurement process.
Set up details:
The set-up consists of an optical rail with two permanently mounted rotation stages for angles theta and phi. The rotation stage for phi has a hollow shaft that is compatible with the LED test sockets from Instrument Systems (all except LED-850). The optical probe is located at the opposing end of the optical rail, and can be positioned at any distance between 5 and 70 cm with respect to the LED. The whole set-up is contained in a lightproof housing with a hinged cover.