The operation steps of an integrating sphere spectrophotometer system

As an emerging light source, LED is very different in its own structure and luminous characteristics compared with traditional light sources. Due to the self-absorption effect of the LED itself and the measurement error caused by the inner shield of the integrating sphere, the traditional integrating sphere luminous flux measurement device is used to measure the luminous flux of the LED. The position of the light source and the screen in the traditional integrating sphere device should be adjusted to reduce the luminous flux measurement error. The data simulated by the software and theoretical calculations prove that the LED should be placed on the inner wall of the integrating sphere and 90° in the same plane as the detector probe.

High Precision Spectroradiometer Integrating Sphere System 

The difficulty of the light source of light source is the test of light flux. Compared with the traditional light source, due to the particularity of LEDs, although the International Lighting Commission (CIE) and the measurement research institutions of the United States, Canada and other countries have proposed the test method of LED optical flux, it has not been recognized internationally to this day Simple test method with similar optical flux test methods.

The existing LED optical flux test methods exist, including: ① The use of optical battery detectors cannot achieve the accurate matching of LEDs to see function v (λ) at all spectral points, especially the existing detectors in blue and red waves are large. Cause test errors; ② Placing objects such as transmission screens in the integral ball along the use of traditional light source testing methods. Because the points of the LED are generally small, even only 5cm in diameter, the point ball theory will not be satisfied, resulting in the original rational error of the test of the test of the test; ③ If the standard light is placed on the inner surface of the integral ball, the conventional standard lights that shine in all directions will not be used, and the LED standard light is difficult to achieve spectral standards. The above problems have made the test of LED optical flux have not yet been perfected and unified, which has also affected the discrimination of LED performance, which is not conducive to the development of the LED industry. The main problem that this article focuses on and discussed is the reasonable position of the LED in the integrating sphere device that measures the total light flux of LED, that is, whether the LED can be placed in the inner wall of the integrating sphere instead of the sphere heart.

1. The measurement principle of the total light flux of LED
There are two methods: absolute measurement and relative measurement of LED total optical flux. The relative measurement method is simple and easy to measure than the absolute measurement method. The integrating sphere used for the relative measurement of the light flux is a hollow complete ball shell. The inner wall of the sphere is sprayed with a white drift layer evenly. A window is opened on the sphere wall of the window detector.

2. The operation step of integrating sphere
The importance is self -evident as the main measurement tool for testing the LED lighting fixture as the main measurement tool for testing LED lighting fixtures. If the role of equipment is also very important, it is necessary to talk about the standard operation specifications of the device here. There are two parts of the standard operation specifications mentioned now: the first point is the standard specification environment, that is, the laboratory requirements; the second point is the operator’s own skill level and operating specifications.

The following will briefly explain the relevant details and requirements
The first part of the standard and standard environment has such requirements for the optical laboratory: the size of the room, this should be judged according to the size of the equipment and the height of the equipment; the second is the air flow, temperature and humidity, and safety protection measures in the laboratory. Essence these are just a brief explanation. Regarding the requirements of laboratory, relevant standards have requirements.

The second part is the point to be said. First of all, we know what equipment composition of the spectrometer & integration sphere system: a complete set of spectrometer accumulation sphere systems by the spectroradiometer, optical fiber, digital power meter(measurement of electrical ginseng), AC power supply (power supply to the measured material), DC power supply (DC power supply ( Power measuring power supply to standard lights or DC inputs), integrating sphere (judgment according to the size of the lamp measurement), standard lights (setting the integrating sphere standard) and cabinet (integrated all equipment).

First of all, you need to do the following steps before the test
1. Check the connection of all equipment and confirm that all the connection is correct and safe (the connection here includes the connection between the equipment and the equipment and the power supply supply);
2. Open the computer software and set related parameters (such as setting data and parameters needed);
3. Install the standard light in the correct position in the integral ball. Please follow the laboratory operation standards;
4. After installing the standard light, turn on the DC DC power supply, and enter the software in the setting of the standard light calibration report one by one. After confirming, click to start the preheating standard light and standard. After the standard is successful, turn off the DC power supply to remove the standard light, and switch the power to AC AC power supply;
5. Install the lamp (please note that the type of lamps is required. If the lamp is tested, the lamps are glowing around, such as LED ball bubbles, CFL energy -saving lamps, etc. The lamp measurement is directed, such as street lights, LED panel lights, etc. It is best to install the lamp on the position of the integral ball -side opening to do 2π test), install the lamp measurement, turn on the AC power supply, and set it in the test software to set up a quilt. The warm -up time of the lamp is usually stabilized for the LED light source output for about 10 minutes;
6. After the warm -up, the software will automatically analyze and calculate the corresponding data. At this time, the software interface will display the test results and print out the test report;
7. After completing the above actions, you need to turn off the power and total control power switch of each instrument;

Test report as below

LPCE-2 Test Report

3. Application of integrating sphere
1. Light receiver
As a optical receiver, the light to be measured into the integrating sphere through a small hole, and one or two photoelectric detectors (such as silicon optical pipes or photoelectric pipes) are installed on the inner wall of the integrating sphere. The light current output by the photoelectric detector is proportional to the illumination of the inner wall of the integrating sphere. That is, it is proportional to the optical flux of the integral ball. Then, through the professional CMS software analysis, the output light current changes, and then calculate the changes in the light flux in the uniform light accumulation.

2. Optical meter
There are two holes at the ends of the horizontal axis of the uniform light source of the integrating sphere. One end is the light input part, and the other end is the light output part. In the light output section, the optical detector and optical degree are arranged to detect the brightness or illuminance of the output. Before leaving the factory, the system needs to be calibrated to obtain system parameters.

3. Uniform surface lighting
A few light bulbs are arranged on the inner wall of the integrating sphere evenly and the inner wall of the light outlet hole. The light emitted by the light bulb has spread multiple times through the inner wall, forming a uniform and bright luminous spherical surface, which can be used as the surface of an object that is measured by the measuring system. It has uniform brightness and large vision (2W> 140 degrees) Basically consistent with the outlet). The uniform light source of the integral ball is used to measure the gradient coefficient of the photographic mirror and the uniformity of the surface illuminance.

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