 Wysłany: Nie 10:10, 06 Mar 2011 Temat postu: discharge lamps are also used LED |
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| LED preparation flux are smaller than the white LED. The white LED luminous flux higher than the blue LED is due to what?
First of all, to understand three basic concepts. Radiation flux (symbols: ξ, unit: W / W), said beam of light through the radiated power per unit area. For a given frequency of light near the relative radiation flux distribution function can be used e (λ) to describe. For the light of a wavelength λ, and its radiation flux can be expressed as: ξ = e (λ) dλ. See the function as (symbol: ν (λ)),restaurant board, characterized by the subjective feeling of the human eye to light. Radiation flux sufficient to describe the brightness of light, because the same flux of light,LED sign, due to different frequencies, the human eye's visual feel intensity is different. Yellow green eyes on the most sensitive to the infrared and ultraviolet are not caused by vision. In order to characterize the objective of the radiation flux and the human relationship between the subjective feelings, introduced as the see function ν (λ) concept. If a wavelength λ of 555 nm light of a wavelength of light, produce the same bright and dark vision are required radiation flux Δξλ and Δξ555nm, then the ratio: ν (λ) = Δξλ / Δξ555 nm is called as See function. Flux (symbol: Φ, Unit: lumens / lm), characterized by visual light intensity per unit of time of light energy through an area known as the radiation energy flux through this area. Absolute black body temperature in the solidification of platinum, from 5.305 * 103 cm2 area on the radiation from the luminous flux is 1 lm. Then, to further understand the meaning of luminous flux, light flux caused by the human eye or visual intensity luminous flux Ф, which is equal to radiation flux and the product of functions depending see. Λ as in the case of a band of light,business neon sign, its luminous flux can be expressed as: dФλ = kmν (λ) e (λ) dλ (3-1) where km is called the maximum efficiency,electric signs, and is a constant. Yellow phosphor white LED conversion because the role of the main spectral wavelength of 555nm the human eye is about the most sensitive, as shown in Figure 2.1 corresponds to the main white light spectrum wavelength is 548.2nm, and blue LED. LED primary wavelengths generally between 450-470nm . Question four: Our clients reflect the color of bluish white light LED, which is why? A: This question is a LED packaging factory sales engineer advice to me a problem. To solve this problem, I took the sample test, test analysis and recommendations of the three steps to answer. Measured by light-color integrated power system testing low-power blue LED (chip dominant wavelength :460-462nm) of the parameters, change the drive current (interval 5mA), record the voltage. |
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