Utilizing Integrating Sphere and Digital Power Meter for Measurement Applications

Integrating sphere is an empty cavity sphere with white diffuse material coated on its inner wall, also known as lightmeter, light sphere, etc. One or several windows are opened on the sphere wall to serve as light inlet and receptacle of light receiver. The inner wall of the integrating sphere should be a good spherical surface, usually requiring that its deviation from the ideal surface should not be greater than 0.2% of the inner diameter. The inner wall of the sphere is coated with ideal diffuse material, that is, the diffuse coefficient is close to 1. The integrating sphere system consists of spectrometer, standard light source, DC power supply, AC power supply, parameter meter for measuring light flux, color temperature, wavelength, chromaticity, voltage and current, etc.

LISUN LPCE-2 Integrating Sphere Spectroradiometer LED Testing System is for single LEDs and LED lighting products light measurement. LED’s quality should be tested by checking its photometric, colorimetric and electrical parameters. According to CIE 177, CIE84,  CIE-13.3, IES LM-79-19, Optical-Engineering-49-3-033602, COMMISSION DELEGATED REGULATION (EU) 2019/2015, IESNA LM-63-2, IES-LM-80 and ANSI-C78.377, it recommends to using an array spectroradiometer with an integrating sphere to test SSL products. The LPCE-2 system is applied with LMS-9000C High Precision CCD Spectroradiometer or LMS-9500C Scientific Grade CCD Spectroradiometer, and a-molding integrating sphere with holder base. This sphere is more round and the test result is more accruate than the traditional integrating sphere.

I. The working principle of the integrating sphere
The light is collected by the integrating sphere through the sampling port, after multiple reflections inside the integrating sphere, the light will be evenly distributed in all positions inside the sphere. When using the light in the sphere to measure, it can make the results of our measurement more reliable. The advantage of the integrating sphere structure is that it can reduce and eliminate the measurement errors caused by the shape of the light, divergence angle and response differences at different positions of the detector.

II. The digital power meter is an electronic measuring instrument used to measure voltage, current, power, etc.
Uses: It is mainly used to measure power parameters of related instruments and meters, such as voltage, current, power, power factor, etc.
Classification:
1. Digital power parameter meters, single-phase power parameter meters and three-phase power parameter meters are the main types of power parameter comprehensive meters. Digital power meter adopts tablet technique, smaller volume, more stable quality, rich interface function and measurement function, more comprehensive measurement function, such as harmonic, PWM wave, no-load loss, etc., which can meet the requirements of production frequency product detection in the laboratory.
2. According to the test voltage phase line, digital power meters can be divided into single-phase wattmeters and three-phase wattmeters. The single-phase wattmeter is widely used in the measurement of TV sets, transformers, etc., while the three-phase wattmeter is suitable for the parameter measurement of three-phase instruments such as motors.
3. Digital wattmeters can be divided into AC wattmeters, DC wattmeters or AC/DC wattmeters according to the test accuracy, and the corresponding models can be selected according to the actual application needs.
4. Digital wattmeters can be divided into general wattmeters and high precision wattmeters according to the test accuracy. The accuracy of the wattmeter on the market is generally 0.5 level, that is, the error is 0.005; high precision can be as high as 0.0001.

III. Steps to measure the LED light with integrating sphere

1. Preparation: prepare a suitable size integrating sphere, a standard light source with light flux close to the light source of the lamp, ambient temperature around 25 degrees Celsius, and avoid wind blowing into the integrating sphere;
2. Calibration: Install the standard light source in the integrating sphere, connect the current source and the power meter, and then turn on the standard light source. Set to continuous test at the software operation interface of the integrating sphere until the light flux reaches a stable value, and record the light flux value;
3. Calibration: The calibration operation is similar to the inspection, but the calibration needs to be calibrated before turning on the standard light source. After the light flux reaches a stable value, input the standard color temperature and standard light flux of the standard light source into the software operation interface of the integrating sphere, and then click Start calibration, the integrating sphere tester will automatically complete the calibration;
4. Test sample: Install the sample in the integrating sphere, turn on the sample, close the integrating sphere, and start the test. After the light flux is stable, record the value.

IV. Measurement Method of Integrating Sphere
The integrating sphere tester adopts the relative comparison method. During measurement, the standard light source needs to be calibrated first, and then compared with the standard light source value to calculate the actual measurement value of the integrating sphere. When using the integrating sphere tester to measure, install the standard light source in the integrating sphere, connect the current source and the electric parameter meter, and then turn on the standard light source. Adjust on the software operation interface of the integrating sphere. At this time, the electric parameter meter starts to work, and the current, voltage and power values appear on the frequency. Until the flux reaches a stable value, record its flux value and current value. Therefore, the electric parameter meter of the integrating sphere is an important device for light intensity detection. Whether the light emission is from weak light source (such as fluorescence) or from high-energy pulsed laser, the electric parameter meter is indispensable in laboratory production departments or working field and other application environments.

Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.

Our main products are Goniophotometer, Integrating Sphere, Spectroradiometer, Surge Generator, ESD Simulator Guns, EMI Receiver, EMC Test Equipment, Electrical Safety Tester, Environmental Chamber, Temperature Chamber, Climate Chamber, Thermal Chamber, Salt Spray Test, Dust Test Chamber, Waterproof Test, RoHS Test (EDXRF), Glow Wire Test and Needle Flame Test.

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Tags：LPCE-2 (LMS-9000)