Goniophotometer is a test device to measure the light emitted from a light source with different angles.
Goniophotometer word constituted from goniometer which use to measure angles and photometer which use to measure the light. Goniophotometer device also has the same equipment that measures angle and light.
Goniophotometer measures distribution and photometric properties of light emitted from different angles from a light source. Goniophotometer can measure light intensity (candela), light level (lux) and brightness (cd/m2).
It is possible to calculate lumen value of light source by using the data of light intensity. Light intensity values of a light source with different angles have taken. These values use to find total light output which means lumen by mathematical calculations. If the measurement of lumen made by this way, the accuracy will be high.
The tests with goniophotometer should be done in a dark room. The requirements of the room are determined by the manufacturer of test device. Room sizes, wall paint, and temperature are important in goniophotometer measurements. If the darkroom does not meet the manufacturer’s specifications, measurement can be incorrect.
Ambient temperature should be 25°C to do the test correctly. Room sizes can be changed according to the lamp type to be tested and the test device. Wall of the room should be painted in flat black paint which do not reflection feature.
Instead of goniophotometer, the integration sphere is generally used for lumen measure. Because there is no need for a darkroom in this method and can be measured more quickly.
Goniophotometer device is used to do performance tests of light equipment in lighting and automotive sectors. Light measurements of traffic signal lamps are also performed with goniophotometer.
In addition to devices with light, reflective of traffic signs and other reflective materials can be measured by goniophotometer.
LDT (EULUMDAT) and IES files are obtained after the measurement of light distribution. Lighting simulations can be performed by transferring these files to software such as DIALux.
Goniophotometer is used to design, development, production and quality tests of devices with light.