What are the three goniophotometer types?

Goniophotometer is the main measurement equipment for the light distribution performance test of lamps and luminous. It can be used to measure the spatial light intensity distribution of lamps or light sources, total luminous flux and lamp efficiency and other parameters. The composition of the Goniophotometer system includes: precision turntable and control system, spectrum analysis system, standard lamp, alignment system, computer processing system and other parts. LISUN design different goniophotometer types according to market survey.

Different goniophotometer types, the test method is different. Depending on the arrangement of the measuring light path, two measurement schemes can be used to measure the luminous flux: the illuminance integral method and the luminous intensity integral method.
1. Illuminance integral method. There is no limit to the measurement distance, and the required measurement space is small. As long as the illuminance can be measured, an accurate total luminous flux can be obtained even if the distance is short. It can be measured with a compact goniophotometer, by measuring the illuminance distribution of the light source in the space and integrating the whole space to obtain the total luminous flux. Because it is not sensitive to the measurement distance and the installation position of the light source, and can avoid the use of mirrors, it can achieve high measurement accuracy. It is the method recommended by CIE to achieve the luminous flux reference unit.
2. Light intensity integration method. The light intensity integration method measures the light intensity distribution of the light source in the space, and integrates the whole space to obtain the total luminous flux. To measure the light intensity distribution, a sufficient distance is required. The measured object can be regarded as a point light source, and the light intensity can be measured using the inverse square of the distance.

Goniophotometers are mainly divided into below goniophotometer types: rotating lamps, rotating detectors, and fixed lamps.
1. Luminaire Rotary Goniophotometer
1) Also known as horizontal goniophotometer, it has simple structure and low cost.
2) During the test, the detector is fixed, the lamp is installed horizontally, and the lamp rotates around its own horizontal axis and vertical axis.
3) After testing the illuminance value, the light intensity can be calculated according to the distance between the light source and the probe.
4) Because the installation direction of the lamp during test and actual use is usually inconsistent, and the rotation will destroy the thermal balance and change the light output, so it will affect the measurement accuracy.

2. Center rotating mirror type Goniophotometer
1) The light source is installed on the rocker arm and rotates in the opposite direction and synchronously around the reflector in a considerable space.
2) The structure is complex, the cost is high, and a large installation space is required. The synchronization error is an unavoidable principle error.
3) The airflow generated by the rotation causes a large change in the temperature of the sample, and the space movement will also cause the HID light source to be affected by the magnetic field, and the measurement results are relatively unstable.

3. Circular motion reflector type Goniophotometer
1) The lamp rotates on its own axis, the reflector rotates around the lamp, and the probe synchronously tracks the reflected light.
2) The C-γ coordinate system measurement method can be realized, which meets the LED measurement requirements of CIE No.70 and LM-79.
3) It is suitable for measuring the spatial light intensity distribution and all luminosity parameters of indoor lighting fixtures, floodlight fixtures, and road lighting fixtures.

High Precision Rotation Luminaire Goniophotometer

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