From the current mechanism and structure of white LED products, the white LED is used to measure the merits of the parameters generally have the following nine.
1, the white LED current / voltage parameters (forward and reverse)
White LED has a typical PN junction voltage characteristics, through a direct impact on current white LED luminance and PN series and parallel combinations together, with each white LED-related characteristics must match in exchange must also consider its anti-state the electrical characteristics. Therefore, they must be tested at the operating point forward current and forward voltage drop and reverse leakage current and reverse breakdown voltage and other parameters.
2, the white LED luminous flux and radiant flux
The total electromagnetic energy white LED per unit time is called radiant flux emitted, which is the optical power (W). For lighting with white LED light source, more concerned about the visual effects of lighting, radiant flux that is emitted from the light source can cause the amount of that part of the human eye perceives, called flux. The ratio of electric power to the device, said radiation flux white LED radiation efficiency.
3, white LED light intensity distribution curve
The light intensity distribution curve is used to represent the distribution of the light emitted by the LED in the direction of the space. In lighting applications, calculating face LED illumination uniformity and spatial arrangement of the light intensity distribution is the most basic data. For space beam is rotationally symmetric distribution LED, with a plane through the beam axis of the curve can be expressed; for elliptical distribution of the light beam LED, is used elliptical curve length of the beam axis and the axis perpendicular to the plane of the two to represent; for asymmetric complex graphics, graphic curve of the beam axis is generally used more than six sections to represent.
4 white LED spectral power distribution
White LED spectral power distribution represents the wavelength dependence of the radiation power function, both to determine the color of light emission, but also determine its luminous flux and color rendering index. Typically relative spectral power distribution with the text S (λ) represents the spectral power along both sides of the peak decreased to 50% of its value, corresponding to the difference between the two wavelengths (Δλ = λ2-λ1) is the spectral band.
5 white LED chromaticity coordinates
For the three primary colors of red (R), green (G), and blue (B), x = R / (R + G + B), y = G / (R + G + B), z = (R + G + B) . Since x + y + z = 1, so just give the value of x and y, we can uniquely identify a color, which is commonly referred chromaticity diagram. In terms of terms of x, y coordinate system as the plane, with a colorimetric assay method to measure the nature of various colors x, y values, and plotted in the coordinate plane, you can get a chromaticity diagram. Any tongue-shaped curve on the edge of the chromaticity diagram that represents a certain wavelength of light hue, curve and any point within the human eye can see are showing a particular color mixed light. Wherein the color temperature value of white region feature point table A., B, C, D, E of the color coordinate values.
6, white LED color temperature and color rendering index
For white LED light color, etc. substantially white light, with color coordinates can accurately express the apparent color of the light source, but the specific values and habits is difficult to sense light and color together. It is often called the orange color cast light "warm" and the more Chi-white or blue Shaopian called "cool", and therefore, the light color to represent the color temperature of the light source will be more intuitive.
7, white LED thermal performance
Lighting LED luminous efficiency and power increase is one of the key issues of the current development of LED industry. At the same time, LED PN junction temperature and shell heat issues is particularly important, generally indicated by the thermal resistance, case temperature, junction temperature and other parameters.
8, radiation safety white LED
Currently, the International Electrotechnical Commission (IEC) will be equal to the product LED semiconductor laser radiation safety requirements for testing and demonstration. Because LED is a narrow beam, high-brightness light-emitting device, taking into account the radiation may harm the human eye retina, for LED applications on different occasions, the international standard specifies the requirements for effective radiation limits and test methods. Currently in the EU and the United States radiation safety, LED lighting products as a mandatory security requirements to implement.
9, white LED reliability and life
Reliability LED indicators for the ability to work properly in a variety of environments to measure the quality of life index evaluation of available LED product cycle, usually expressed in active life or ending life. In lighting applications, the effective life is the LED at rated power, the flux decay to a percentage of the initial value (predetermined value) when the duration.
(1) Average life: a number of LED lights at the same time, when after a period of time, not bright LED ratio reached 50% of the time.
(2) economic life: taking into account the damage to the LED light output attenuation and the situation under which total output is reduced to a specific percentage of the time when this ratio was 70% for the outdoor light, indoor light sources when used in 80%.
1, the white LED current / voltage parameters (forward and reverse)
White LED has a typical PN junction voltage characteristics, through a direct impact on current white LED luminance and PN series and parallel combinations together, with each white LED-related characteristics must match in exchange must also consider its anti-state the electrical characteristics. Therefore, they must be tested at the operating point forward current and forward voltage drop and reverse leakage current and reverse breakdown voltage and other parameters.
2, the white LED luminous flux and radiant flux
The total electromagnetic energy white LED per unit time is called radiant flux emitted, which is the optical power (W). For lighting with white LED light source, more concerned about the visual effects of lighting, radiant flux that is emitted from the light source can cause the amount of that part of the human eye perceives, called flux. The ratio of electric power to the device, said radiation flux white LED radiation efficiency.
3, white LED light intensity distribution curve
The light intensity distribution curve is used to represent the distribution of the light emitted by the LED in the direction of the space. In lighting applications, calculating face LED illumination uniformity and spatial arrangement of the light intensity distribution is the most basic data. For space beam is rotationally symmetric distribution LED, with a plane through the beam axis of the curve can be expressed; for elliptical distribution of the light beam LED, is used elliptical curve length of the beam axis and the axis perpendicular to the plane of the two to represent; for asymmetric complex graphics, graphic curve of the beam axis is generally used more than six sections to represent.
4 white LED spectral power distribution
White LED spectral power distribution represents the wavelength dependence of the radiation power function, both to determine the color of light emission, but also determine its luminous flux and color rendering index. Typically relative spectral power distribution with the text S (λ) represents the spectral power along both sides of the peak decreased to 50% of its value, corresponding to the difference between the two wavelengths (Δλ = λ2-λ1) is the spectral band.
5 white LED chromaticity coordinates
For the three primary colors of red (R), green (G), and blue (B), x = R / (R + G + B), y = G / (R + G + B), z = (R + G + B) . Since x + y + z = 1, so just give the value of x and y, we can uniquely identify a color, which is commonly referred chromaticity diagram. In terms of terms of x, y coordinate system as the plane, with a colorimetric assay method to measure the nature of various colors x, y values, and plotted in the coordinate plane, you can get a chromaticity diagram. Any tongue-shaped curve on the edge of the chromaticity diagram that represents a certain wavelength of light hue, curve and any point within the human eye can see are showing a particular color mixed light. Wherein the color temperature value of white region feature point table A., B, C, D, E of the color coordinate values.
6, white LED color temperature and color rendering index
For white LED light color, etc. substantially white light, with color coordinates can accurately express the apparent color of the light source, but the specific values and habits is difficult to sense light and color together. It is often called the orange color cast light "warm" and the more Chi-white or blue Shaopian called "cool", and therefore, the light color to represent the color temperature of the light source will be more intuitive.
7, white LED thermal performance
Lighting LED luminous efficiency and power increase is one of the key issues of the current development of LED industry. At the same time, LED PN junction temperature and shell heat issues is particularly important, generally indicated by the thermal resistance, case temperature, junction temperature and other parameters.
8, radiation safety white LED
Currently, the International Electrotechnical Commission (IEC) will be equal to the product LED semiconductor laser radiation safety requirements for testing and demonstration. Because LED is a narrow beam, high-brightness light-emitting device, taking into account the radiation may harm the human eye retina, for LED applications on different occasions, the international standard specifies the requirements for effective radiation limits and test methods. Currently in the EU and the United States radiation safety, LED lighting products as a mandatory security requirements to implement.
9, white LED reliability and life
Reliability LED indicators for the ability to work properly in a variety of environments to measure the quality of life index evaluation of available LED product cycle, usually expressed in active life or ending life. In lighting applications, the effective life is the LED at rated power, the flux decay to a percentage of the initial value (predetermined value) when the duration.
(1) Average life: a number of LED lights at the same time, when after a period of time, not bright LED ratio reached 50% of the time.
(2) economic life: taking into account the damage to the LED light output attenuation and the situation under which total output is reduced to a specific percentage of the time when this ratio was 70% for the outdoor light, indoor light sources when used in 80%.
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