Phosphor yana nufin waɗanda suke shirya rarrabi a kan radiyasiya ko samun kayayyakin. An haɗa shi daga kalmar Greek "phosphoros", wanda yana nufin "light-bringer". Phosphors suna da semiconductors, wadanda suke da uku energy bands: valence band, conduction band, da forbidden band.
Valence band yana daya da takamarta da ake biyuwa electrons. Conduction band yana daya da takamarta da ake biyuwa electrons za su yi lokaci. Forbidden band yana daya da gap bayan valence da conduction bands, wanda ba za a iya kasance electrons.
Phosphors suna da imanen da ke dogara da impurities ko dopants, wadanda suke yin energy levels additional a kan forbidden band. Wanen energy levels suna da muhimmiya ga electrons ko holes (positive charges) wadanda suke ci gaba da radiyasiya ko samun kayayyakin. Idan electrons ko holes sun zo zuwa hali na biye, suke tattauna energy as photons of light.
Yadda Tsakiyar Phosphor Coating Ya Canza Radiyasiya UV Zuwa Rarrabi Da Ake Iya Ƙunshi
Ingantaccen radiyasiya UV zuwa rarrabi da ake iya ƙunshi da tsakiyar phosphor yana nufin fluorescence. Fluorescence yana faru idan atom ko molecule yana ci gaba da photon of high-energy radiation da ke tattauna photon of lower-energy radiation. Farko da ake biyo bayan absorbed da emitted photons yana ci gaba da heat.
Wannan diagram yana bayyana yadda fluorescence yake faru a kan tsakiyar phosphor made of zinc sulfide (ZnS) doped with silver (Ag) as an activator.
Model of Zinc Sulfide
A – B :- Electron Jump
B – E :- Electron Migration
E – D :- Electron Jump
D – C :- Electron Jump
A – C :- Hole Migration
Photon of UV radiation with a wavelength of 253.7 nm strikes the phosphor coating and excites an electron from a sulfur (S) atom to a zinc (Zn) atom. This creates a positive hole in the valence band and a negative ion (Zn^-) with an extra electron in the conduction band.
The extra electron migrates from one Zn^- ion to another through the crystal lattice in the conduction band.
Meanwhile, the positive hole moves from one S atom to another in the valence band until it reaches an Ag atom, which acts as a trap.
The Ag atom captures the electron from the Zn^- ion near it and becomes neutral (Ag^0). This releases a photon of visible light with a longer wavelength than the UV photon.
The electron from the Ag^0 atom jumps back to the S atom where the hole was created, completing the cycle.
Rarrabin da ake iya ƙunshi yana dogara da farko bayan Ag trap level da Zn^- level. Dopants different can create different trap levels and thus different colors. For example, copper (Cu) can produce green light, manganese (Mn) can produce orange light, and cadmium (Cd) can produce red light.
Nau'ukan da Muhimmancin Tsakiyar Phosphor Coating
Akwai nau'ukan da duka da tsakiyar phosphor coating wadanda suke amfani da su a kan lambu-lambu fluorescent, depending on the desired color and quality of light. Some common types are:
Halophosphate: This is a mixture of calcium halophosphate (Ca5(PO4)3X) and magnesium tungstate (MgWO4), where X can be fluorine (F), chlorine (Cl), or bromine (Br). It produces white light with a yellowish or bluish tint, depending on the ratio of F to Cl or Br. It has a low color rendering index, which means that it cannot render colors accurately. The lamp efficacy is about 60 to 75 lm/W.
Triphosphor: This is a mixture of three different phosphors, each emitting a primary color of red, green, and blue. The combination of these colors produces white light with a high color rendering index of 80 to 90 and a lamp efficacy of about 80 to 100 lm/W. Triphosphor lamps are more expensive than halophosphate lamps, but they offer better color quality and energy efficiency.
Multi-phosphor: This is a mixture of four or more phosphors, each emitting a different color of the visible spectrum. The aim is to create a smooth and continuous spectral distribution that mimics natural daylight. Multi-phosphor lamps have the highest color rendering index of over 90 and a lamp efficacy of about 90 to 110 lm/W. They are also the most expensive type of fluorescent lamps, but they provide the best color performance and visual comfort.
Tsakiyar phosphor coating can be applied in different ways, such as by spraying, dipping, or electrophoretic deposition. The thickness and uniformity of the coating affect the light output and quality of the lamp. The phosphor coating can also degrade over time due to exposure to heat, humidity, and UV radiation, resulting in reduced brightness and color shift.
Phosphor coating is widely used in various applications that require high-quality and energy-efficient lighting, such as:
General lighting: Phosphor coating can provide white light with different color temperatures and color rendering indices, depending on the needs and preferences of the users. For example, warm white light (2700 to 3000 K) is suitable for residential and hospitality settings, while cool white light (4000 to 5000 K) is preferred for offices and commercial spaces.
Display lighting: Phosphor coating can enhance the appearance and attractiveness of products and artworks by providing vivid and accurate colors. For example, tri-phosphor or multi-phosphor lamps can be used for displaying fruits, vegetables, meats, flowers, paintings, etc.
Medical lighting: Phosphor coating can improve the visibility and diagnosis of medical conditions by providing high-quality and natural-looking light. For example, multi-phosphor lamps can be used for surgical procedures, dental examinations, skin treatments, etc.
Specialty lighting: Phosphor coating can create various effects and functions by emitting different colors or wavelengths of light. For example, black light lamps use phosphors that emit UV radiation that can make certain materials glow in the dark. Germicidal lamps use phosphors that emit UV-C radiation that can kill bacteria and viruses. Grow lamps use phosphors that emit red and blue light that can stimulate plant growth.
Conclusion
Tsakiyar phosphor coating yana daya da muhimmin yanayin lambu-lambu fluorescent wanda suke canza radiyasiya UV zuwa rarrabi. Yana dogara da rarrabin da ake iya ƙunshi da lambu-lambu. Akwai nau'ukan da duka da tsakiyar phosphor coating wadanda suke amfani da su a kan abubuwa daban-daban. Tsakiyar phosphor coating can provide energy-efficient and high-performance lighting solutions for various needs and preferences.
Statement: Respect the original, good articles worth sharing, if there is infringement please contact delete.
