Integrating sphere> is a hollow sphere whose inner wall is coated with white diffuse reflection material, also known as photometric sphere, optical flux sphere, etc. One or several windows are opened on the wall of the ball, which are used as light inlet holes and receiving holes for placing light receiving devices. The inner wall of the integrating sphere should be a good spherical surface, and it is usually required that its deviation relative to the ideal spherical surface should not be greater than 0.2% of the inner diameter. The inner wall of the ball is coated with an ideal diffuse reflective material, that is, a material with a diffuse reflectance close to 1. The integrating sphere system is composed of a spectrometer, a standard light source, a DC power supply, an AC power supply, and an electrical parameter measuring instrument>, providing calibration of luminous flux, color temperature, wavelength, chromaticity, voltage, current and other items.
1. The working principle of the integrating sphere>
The light is collected by the integrating sphere through the sampling port as shown in the figure below. After multiple reflections inside the integrating sphere, the light will exist in various positions inside the integrating sphere very uniformly. When using the light inside the integrating sphere to measure, it allows us to measure The result is more reliable. The advantage of using the integrating sphere structure is that it can reduce and eliminate the measurement error caused by the shape of the light, the divergence angle, and the difference in responsivity at different positions on the detector.
2. Electrical parameter measuring instrument>
It is an electronic measuring instrument used to measure voltage, current, electric power, etc.
Uses: It is mainly used to measure the electrical parameters of related instruments and meters, such as voltage, current, electric power, power factor, etc.
1. Electrical parameter comprehensive measuring instruments mainly include digital power parameter measuring instruments, single-phase electric parameter measuring instruments and three-phase electric parameter measuring instruments, etc. Among them, the digital power meter adopts surface-mount technology, which is smaller in size and more stable in quality. Interface function and measurement function, the measurement function is more comprehensive, such as harmonic wave, PWM wave, no-load loss, etc., which can meet the testing requirements of laboratory power frequency products.
2. The digital power meter can be divided into single-phase power meter according to the test voltage phase linePower meter and three-phase power meter. Single-phase power meter is widely used in the measurement of TV sets, transformers, etc., and three-phase power meter is suitable for parameter measurement of three-phase instruments such as motors.
3. Digital power meters can be divided into AC power meters, DC power meters or AC and DC power meters, and the corresponding models can be selected according to actual application needs.
4. Digital power meters can be divided into general power meters and high-precision power meters according to the test accuracy. The accuracy of conventional power meters on the market is generally 0.5, that is, the error is 5/1000; the high precision can be as high as 1/10,000 Five.
3. The steps of measuring LED lights with an integrating sphere>
1. Preparation: Prepare an integrating sphere of appropriate size, a standard light source with a luminous flux close to that of the lamp light source, and an ambient temperature of about 25 degrees to avoid wind blowing into the integrating sphere;
2. Inspection: Install the standard light source into the integrating sphere, connect the current source and power meter, and then turn on the standard light source. On the operating interface of the integrating sphere software, adjust to continuous testing until the luminous flux reaches stability, and record the luminous flux value;
3. Calibration: The operation of calibration is similar to that of inspection, the difference is that zero calibration must be performed before lighting the standard light source. After the luminous flux reaches stability, enter the standard color temperature and standard luminous flux of the standard light source on the operating interface of the integrating sphere software, and then click to start calibration, and the integrating sphere tester will automatically complete the calibration;
4. Test the sample: install the sample in the integrating sphere, light the sample, close the integrating sphere, and start the test. After the luminous flux is stable, record the value.
4. Measurement method of integrating sphere>
The Integrating Sphere> tester adopts the relative comparison method. When measuring, it is necessary to use a standard light source to calibrate first, and then calculate the actual measurement value of the integrating sphere by comparing with the value of the standard light source.
When using the integrating sphere tester to measure, install the standard light source in the integrating sphere, connect the current source and the electrical parameter measuring instrument, and then turn on the standard light source. Adjust the operating interface of the integrating sphere software, and thenmeasure the electrical parameters The instrument will start to operate, and the current, voltage, and power values will appear on the display frequency until the luminous flux reaches stability, and record its luminous flux value and current value. Therefore, the integrating sphere electrical parameter measuring instrument is an important tool for light intensity detection Devices, electrical parameter measuring instruments are mainly used to measure the output of light sources. Whether the light emission comes from weak light sources (such as fluorescence) or from high-energy pulsed lasers, electrical parameter measuring instruments are ideal for laboratory production departments or work sites It is an indispensable tool in various application environments.