The light-emitting device of the LED display is LED, that is, light-emitting diode. Understanding some of the main professional terms and technical parameters of LED can help us choose the right LED display, and it can also help us in the daily maintenance and use of the LED display.
1. What is the luminous intensity (luminance) of the LED?
Answer: Luminous intensity (luminance, I) is defined as: the luminous intensity of a point light source in a certain direction, that is, the amount of light emitted by the luminous body in a unit time, also referred to as luminosity, and the common unit is candlelight (cd, candela). An international candlelight is defined as the luminosity emitted by a candle made of whale fat burning 120 grains per hour, and one grain of cold is equal to 0.0648 grams.
2. What is the unit of luminous intensity (luminance)?
Answer: The commonly used unit of luminous intensity is candlelight (cd, candela). The international standard candlelight (lcd) is defined as 600,000 points perpendicular to the blackbody (its surface area is 1m2) when the ideal black body is at the platinum freezing point temperature (1769℃). One of the luminosity, the so-called ideal black body means that the emissivity of the object is equal to 1, the energy absorbed by the object can be radiated out, so that the temperature has been kept uniform and fixed, the international standard candle (candela) and the old standard candle (candle) interchange The relationship is 1candela=0.981candle.
3. What is luminous flux? What is the unit of luminous flux?
Answer: The definition of luminous flux (φ) is: the energy emitted by a point light source or a non-point light source in a unit time, among which the visual person (the radiant flux that can be felt by humans) is called luminous flux. The unit of luminous flux is lumens (lm for short). 1 lumens (lumen or lm) is defined as the luminous flux of an international standard candle light source in a unit solid arc angle. Since the entire spherical area is 4πR2, the first-class luminous flux is equal to one candle. The emitted luminous flux is 1/4π, or the spherical surface has 4π, so according to the definition of lumens, it can be known that a cd point light source will radiate 4π lumens, that is, φ (lumens) = 4πI (candle light), assuming that △Ω is a small three-dimensional arc Angle, the luminous flux △φ in the △Ω solid angle, then △φ=△ΩI.
4. What is the meaning of a foot candle?
Answer: One foot candle refers to the illuminance on the surface orthogonal to the light one foot away from the light source (point light source or non-point light source) of one candle light. The luminous flux received in a square foot is the illuminance at 1 lumen, and 1ftc=10.76lux.
5. What is the meaning of one meter candle?
Answer: One-meter-candle light refers to the illuminance on the surface orthogonal to the light at a distance of one meter away from a one-candle light source (point light source or non-point light source), called lux (lux, also written as lx), that is, per square meter The luminous flux received inside is the illuminance at 1 lumens (lumens/m2).
6. What is the meaning of lux?
Answer: The illuminance when the received luminous flux per square meter is 1 lumen
7. What is the meaning of illuminance?
Answer: Illuminance (E) is defined as: the luminous flux per unit area of the illuminated object, or the luminosity per unit area of the illuminated object per unit time. The unit is in meter-candles or foot-candles ( ftc) said.
8. What is the relationship between illuminance, luminosity, and distance?
Answer: The relationship between illuminance, luminosity, and distance is: E (illuminance) = I (luminance)/r2 (distance squared).
9. What are the factors related to the illuminance of the subject?
Answer: The illuminance of the illuminated object is related to the luminous intensity of the light source and the distance between the illuminated object and the light source, but has nothing to do with the color, surface properties and surface area of the illuminated object.
10. What is the meaning of light effect (lumens/watt, lm/w)?
Answer: The ratio of the total luminous flux emitted by the light source to the electric power (watts) consumed by the light source is called the luminous efficiency of the light source
11. What is color temperature?
Answer: When the color emitted by the light source is the same as the color radiated by the black body at a certain temperature, the temperature of the black body is the color temperature.
