LED lighting installation must be tested for points

1. luminous intensity detection Light intensity is the intensity of light, is the amount of light emitted within a certain angle. Due to the concentration of light-emitting diode light, the inverse square law is not applicable to short-range situations. cie127 standard for measuring the average normal light intensity provides two conditions: measurement condition A (far-field conditions) and measurement condition B (near-field conditions). The detector area in both cases is 1 cm2. usually, the standard condition b is used to measure the luminous intensity

2.II luminous flux and efficiency of the detection luminous flux is the sum of the amount of light emitted by the light source, that is, the amount of luminescence. Detection methods mainly include the following two: (1) integration method. If the standard luminous flux is called φ s, the luminous flux of the measured lamp φ d = ed × φ s/es. The integration method uses the "point source" principle, simple operation, but due to the color temperature deviation between the standard lamp and the measured lamp, the measurement error is larger. (2) Spectrophotometric method. The luminous flux is calculated by the spectral energy P(λ) distribution. Using a monochromator, the 380 nm ~ 780 nm spectrum of the standard lamp is measured on an integrating sphere, and then the spectrum of the lamp under test is measured under the same conditions, and the luminous flux of the lamp under test is calculated by comparison. Luminous efficiency is the ratio of the luminous flux emitted by the light source to the power consumed. Constant current method is usually used to measure the luminous efficiency of light-emitting diodes.

3. Spectral characteristics of light-emitting diode spectral characteristics of the test including spectral power distribution, color coordinates, color temperature, color rendering index, etc.. Spectral power distribution means that the light of the light source consists of many different wavelengths of colored radiation, and the radiation power of each wavelength is also different. When the light source is arranged in order of wavelengths, this difference is called the spectral power distribution of the light source. The light source is compared and measured with a spectrophotometer (monochromator) and a standard lamp. Color coordinates are the amount of light emitted by a light source expressed numerically on a coordinate diagram. There are various coordinate systems representing the color coordinate chart, and the X and Y coordinate systems are usually used. Color temperature is the amount of the light source's color table (appearance color representation) as seen by the human eye. When the light emitted by a light source is the same color as the light emitted by a **blackbody at a certain temperature, the temperature is the color temperature. In the field of lighting, color temperature is an important parameter to describe the optical properties of a light source. The theory related to color temperature is derived from blackbody radiation and can be obtained from the color coordinates of the light source including the blackbody trajectory. The color rendering index indicates the amount of light emitted by a light source that correctly reflects the color of the object being illuminated. It is usually expressed by the general color rendering index Ra, which is the arithmetic mean of the color rendering index of the light source for eight color samples. Color rendering index is an important parameter of the quality of the light source, it determines the application range of the light source. Improve the color rendering index of white light-emitting diodes is one of the important tasks of light-emitting diode research and development.

4. the effect of temperature on the optical properties of light-emitting diodes Temperature will affect the optical properties of light-emitting diodes. A large number of experiments have shown that temperature affects the emission spectrum and color coordinates of light-emitting diodes.

5. Measurement of light-emitting diode lamp electrical parameters Electrical parameters mainly include forward voltage, reverse voltage and reverse current, they are related to the normal operation of the light-emitting diode lamp, is one of the basis for judging the basic performance of light-emitting diode lamp. Light-emitting diode lamp electrical parameters are measured in two ways: a certain current voltage parameters; when the voltage is constant, test the current parameters. Specific methods are as follows: (1) DC voltage. When the forward current is applied to the light-emitting diode lamp to be tested, the light-emitting diode lamp will appear at both ends of the voltage drop. Adjust the power supply determined by the current value, and the relevant readings recorded on the DC voltmeter, which is the DC voltage of the light-emitting diode lamp. According to the relevant common sense, when the light-emitting diode positive conduction, the resistance is smaller, the ammeter external connection method is more accurate. (2) reverse current. Apply a reverse voltage to the tested light-emitting diode lamp and adjust the voltage regulator. The ammeter reading is the reverse current of the light-emitting diode lamp under test. Similar to DC voltage measurement, due to the reverse conduction when the light-emitting diode resistance is large, so the internal connection of the ammeter.