How to build the darkroom for goniophotometer

1. Best Regards,
James Peng 彭小林
General Manager
Lisun Electronics (Shanghai) Co., Ltd
Tel: +86(21)51083341 ext. 8001 Fax: +86(21)51083342
Cell: +86 138 1866 3384 SKYPE: James.lisungroup
Website: www.Lisungroup.com Email: James@Lisungroup.com
1
How to build the darkroom for Goniophotometer
Goniophotometer is mainly used for light intensity performance measurement of
luminaries and light source, which is the photometry value in different directions in space
and color distribution. Goniophotometer should run in dark room, and what are the
requirements for the test environment?
The size requirements for dark room: for example, such as LISUN LSG-2000 LM-79
Goniophotometer System. According to CIE requirement, dark room consists of 2 parts,
the recommended size of the dark room for Goniometric Rotating Console is
W5.0m*L5.0m*H5.9m; the recommended size of the dark room for Photometric Light
Path is W1.5m*H1.5m*L(15m – 30m). According to the requirements of CIE, the
recommended distance between lamp and photo detector is 6 times than the diameter of
lamp. The recommended size of operating room is no less than W3m*L3m. LISUN
GROUP engineer dept will submit the Lab Design support documents according to the
customer’s real lab size after the formal purchase order was confirmed.
Requirements of eliminating the stray light: the photodetector can only receive the light
reflected by the rotating mirror in the LSG-2000 system. The light given off directly by the
luminaries and reflected by the wall and floor is warded off by the light fence. Internal
surface of the dark room and dark path together with the surface of the light fence should
be painted unpolished black or be covered by black cloth and black carpet.

2. Best Regards,
James Peng 彭小林
General Manager
Lisun Electronics (Shanghai) Co., Ltd
Tel: +86(21)51083341 ext. 8001 Fax: +86(21)51083342
Cell: +86 138 1866 3384 SKYPE: James.lisungroup
Website: www.Lisungroup.com Email: James@Lisungroup.com
2
Temperature of the Environment: Because of the thermal performance of LED, the
photometric value and electronic performance of SSL products are sensitive to the change
of temperature and air movement. Temperature around the lamp or luminaries must be
25℃±1℃ during the test. The temperature should be measured in the distance that is no
more than 1m, and measurement height should be the same with the SSL product.
Temperature sensor should avoid the direct optical radiation of SSL product and other
light source. Therefore, you should place an air conditioner in the dark room to control the
temperature around the lamp to reach the temperature requirement of CIE. If the
measurement is not doing under the recommended temperature, this is a non-standard
condition, which should be remarked in the test report.
Requirements of Airflow: Airflow may be induced by natural aeration, air conditioner or
movement of the luminaries in the goniophotometer, but the speed of the airflow couldn’t
exceed 0.2m/s. The airflow of the tested lamp surface may greatly change the electric
value and photometric value. The testing personnel must not enter the dark room during
the test.
Vibration and shock: When the lamp is in lighting, the vibration couldn’t exceed
10m/s2(4～3000Hz), or the moving scope of the lamp couldn’t exceed 30mm (at most
4Hz).
Smoke, Dust and Moisture: The test environment must free from smoke, dust or moisture.
At the same time, even not during the measurement, smoke, dust or moisture will also
influence the reflectance of the reflecting mirror and induce more stray light. So, the test
room must be kept clean, no smoke and dry. The humidity should be less than 60% RH.
Lisun LSG-2000 Moving Mirror Goniophotometer System is widely applied to Luminaries
manufacturing enterprise and lab, such as Sharp Electronics in Memphis TN(USA), CS
TECH MEXICO, S.A. DE C.V. (Mexico), DORADO Praha s.r.o. (Czech) etc. The reason
why Lisun can win some many customers is because we always practice the motto of right
products, right price and right service. Lisun will continue feedback good quality products
and superior service in the feature.