The essence of light is electromagnetic waves, which is […]
The essence of light is electromagnetic waves, which is a form of energy in a very small part of the entire electromagnetic spectrum. Light is a form of energy that is radiated into the human eye through the optic nerve, which is the part of the spectrum that can be seen by the naked eye. . These rays range in wavelength from 360 to 830 nm and are only a very small fraction of the electromagnetic radiation spectrum. The temperature is much higher than the 50 Hz operating temperature, resulting in a higher color temperature white color table and better color rendering.
Second, the luminous flux
The sum of the energy emitted by the light source and received by the human eye is the luminous flux. In general, the higher the power of the same type of lamp, the greater the luminous flux. For example, a 40W ordinary incandescent lamp has a luminous flux of 350---470lm, while a 40W ordinary straight-tube fluorescent lamp has a luminous flux of about 2800lm, which is 6-8 times that of an incandescent lamp.
The luminous flux received by the unit on the illuminated surface is called illuminance. If the luminous flux received per square meter of the illuminated surface is 1 (1 m), the illuminance is 1 (1x). Unit: Lux (1x). 1 lux (1x) corresponds to the illuminance when the luminous flux on the surface is 1 lumen (1m). In the summer sunshine, the ground illumination at noon is about 5000 1x, the ground illumination in winter is about 2000 1x, and the sunny moonlit night illumination is about 0.2 1x.
The brightness of a light source in a certain direction is the unit projection area of the light source in that direction, and the luminous flux emitted in a unit solid angle. If we regard each object as a light source, then brightness is the degree to which the light source is illuminated, and the illuminance is just to treat each object as the object to be illuminated, using a piece of wood to illustrate, when a certain beam shines on the board, we Talk about how much illumination the board has, and then how much light is reflected by the board to the human eye. It is called the brightness of the board. Then there is the following formula: brightness is equal to the illumination multiplied by the reflectivity. The illuminance of a white cloth and a black cloth in the same position in the same room is the same, and the brightness is different.
Five, light effects
The ratio of the total luminous flux emitted by the light source to the electrical power (watts) consumed by the source is referred to as the efficacy of the source. Unit: lumens / watt (lm / W)
Sixth, color temperature
When the color of the light emitted by the light source is the same as the color of the black body radiated at a certain temperature, the temperature of the black body is referred to as the color temperature of the light source, expressed by the absolute temperature K (kelvim). The theory of blackbody radiation is based on thermal radiation. Therefore, the spectral power distribution of a thermal radiation source such as an incandescent lamp is close to that of a blackbody in the visible region. Both are continuous spectra. The concept of color temperature can fully describe this. The color characteristics of a class light source.
Seven, the relevant color temperature
When the color of the light emitted by the light source is close to the color of the black body radiating at a certain temperature, the temperature of the black body is called the correlated color temperature of the light source, and the unit is K. Since the gas discharge source is generally a discontinuous spectrum and does not completely match the continuous spectrum of blackbody radiation, the correlated color temperature is used to approximate its color characteristics. A light source with a color temperature (or correlated color temperature) below 3300K, the color is reddish, giving a warm feeling. When the color temperature exceeds 5300K, the color is blue, giving a cold feeling. In areas with high temperatures, light sources with a color temperature higher than 4000K are often used, while those with lower temperatures use light sources below 4000K.
Eight, color rendering index
Both sunlight and incandescent lamps radiate a continuous spectrum of red, orange, yellow, green, cyan, blue, purple, etc. in the visible light wavelength range (380nm-760nm). The object shows its true color under the illumination of sunlight and incandescent lamps, but when the object is illuminated by a non-continuous spectrum of gas discharge lamps, the color will have different degrees of distortion. We present the true color of the object to the object. The degree is called the color rendering of the light source. In order to quantitatively evaluate the color rendering of the light source, the concept of color rendering index is introduced. Based on the standard light source, the color rendering index is set to 100, and the color rendering indexes of the remaining light sources are all below 100. The color rendering index is represented by Ra. The larger the Ra value, the better the color rendering of the light source.
Nine, light intensity
The luminous flux emitted by a light source in a unit solid angle in a given direction is called the luminous intensity of the light source in that direction, referred to as the light intensity. Unit: Candela (cd)
Ten, the average life expectancy
Refers to the number of hours that a group of lamps ignite when they have 50% of the lamps that are not lit. Unit: Hour (h) 11. Economic life The integrated beam output is reduced to a specific proportion of hours while considering the damage of the bulb and the attenuation of the beam output. This ratio is 70% for outdoor light sources and 80% for indoor light sources such as fluorescent lamps.
Light source luminous efficiency refers to the ratio of the luminous flux emitted by a light source to the electrical power consumed by the light source. Luminaire efficiency (also called light output factor) is an important criterion for measuring the energy efficiency of a luminaire. It is the ratio between the luminous flux output by the luminaire and the luminous flux output from the illuminator.
Objects with extremely high brightness in the field of view have a strong contrast of brightness, which can cause visual discomfort, called glare. Glare is divided into disabling glare and discomfort glare, which is an important factor affecting quality.
Thirteen, power factor
It is the ratio of the actual input power to the surface power of the line. Its ideal value is 1, and less than 1 causes loss of the conveyor system and increases the load on the power generation equipment.