Fluorescent lamp history
Fluorescent lamp, also known as fluorescent lamp.
The conventional fluorescent lamp, that is, the low-pressure mercury lamp, is a low-pressure arc discharge source that utilizes a low-pressure mercury vapor to emit ultraviolet light after being energized, thereby causing the phosphor to emit visible light.
In 1974, Philips in the Netherlands first developed a phosphor that would emit red, green and blue light that is sensitive to the human eye. The development and application of three primary colors (also known as the three primary colors) phosphors is an important milestone in the history of fluorescent lamps.
After the 1950s, most of the fluorescent lamps used calcium halophosphate, commonly known as halogen powder. The halogen powder is cheap, but the luminous efficiency is not high enough, the thermal stability is poor, the light decay is large, and the luminous flux maintenance rate is low. Therefore, it is not suitable for use in a thin tube diameter compact fluorescent lamp.
In 1974, Philips in the Netherlands first developed a phosphor cerium oxide (red light, peak wavelength 611 nm) that emits red, green and blue light that is sensitive to human eyes. Magnesium polyaluminate (green light, peak wavelength) 541nm) and magnesium polyaluminate bismuth (blue light, peak wavelength of 450nm) mixed into a three-primary phosphor (complete name is rare earth element trichromatic phosphor), its luminous efficiency is high (average luminous efficiency is 80lm) Above /W, about 5 times that of incandescent lamps), the color temperature is 2500K-6500K, and the color rendering index is about 85. Using it as a raw material for fluorescent lamps can greatly save energy, which is the reason for high-efficiency energy-saving fluorescent lamps. It can be said that the development and application of rare earth element trichromatic phosphors is an important milestone in the history of fluorescent lamps. Without a three-primary phosphor, it is impossible to have a new generation of thin-tube compact high-efficiency fluorescent lamps. However, the rare earth element trichromatic phosphor also has its disadvantages, and its biggest disadvantage is that it is expensive.