Dandayi na Nunaƙa Zafi

Takaitaccen LED

Takaitaccen LED yana nufin tattalin kimiyya mai amfani da hanyoyi daban-daban don gina takaitaccen tsakiyar takaice, wanda yanzu ya samu amfani a fannan tattalin kimiyya masu alamomin daidai.

Takaitaccen Light Emitting Diodes ko Takaitaccen LEDs suna yi nasarorin tattalin kimiyya. A baya, LEDs suna iya amfani da su a kan abubuwa masu alama, tattalin bayanai da tattalin gabashin mafi girma. Yanzu, takaitaccen LEDs ana amfani da su a dukkan tattalin kimiyya, ciki har zuwa tattalin tsakiyar birnin da tattalin tsakiyar mutanen. Wannan ya zama babban abubuwa a tattalin kimiyya.

LEDs ba su iya gina takaitaccen tsakiyar takaice na biyu, amma wasu tattalin kimiyya suna iya sa su gina. Abubuwan da suke amfani da su don gina takaitaccen tsakiyar takaice a LEDs sun hada da Wavelength Conversion, Color Mixing, da Homo-epitaxial ZnSe technology.

Wavelength Conversion

Wavelength conversion yana canza radiyacin LED zuwa takaitaccen tsakiyar takaice. Wasu hanyoyi sun haɗa da amfani da blue LED da yellow phosphor, multiple phosphors, ultraviolet LED da RGB phosphors, ko blue LED da quantum dots.

Blue LED and Yellow Phosphor

A wannan hanyoyin wavelength conversion, an amfani da LED wanda yake gina radiyacin lasirin ranar sama ta shahara don shahara yellow phosphor (Yttrium Aluminum Garnet). Wannan yana ba da shahara yellow da blue light, kuma wannan mixturin blue da yellow light yana ba da shahara takaitaccen tsakiyar takaice. Wannan hanyoyi shine hanyoyin da ke da lafiya da kyau don gina takaitaccen tsakiyar takaice.

Blue LED and Several Phosphors

Wannan hanyoyin wavelength conversion yana amfani da multiple phosphors tare da blue LED. Kowane phosphor da ake amfani da shi yana gina ƙarin lasirin ranar idan radiyacin blue LED yake shahara shi. Duk ƙarin lasirin ranar suka dole da original blue light don gina takaitaccen tsakiyar takaice. Amfani da multiple phosphors ba tare da yellow phosphor yana ba da shahara takaitaccen tsakiyar takaice wanda yake da ƙarin wavelength spectrum da ƙarin hanyoyi na CRI da CCT. Amma, wannan hanyoyi shine mafi lafiya da hanyoyin da ke amfani da yellow (YAG) phosphor kawai.

Ultraviolet LED with RGB Phosphors

Hanyoyin uku a wavelength conversion yana amfani da ultraviolet radiation emitting LED tare da red, green, da blue (RGB) phosphors. LED yana gina ultraviolet radiation, ba a iya shahara a nan, wanda yake shahara red, green, da blue phosphors da yake shahara shi. Idan RGB phosphors suka shahara, suka gina radiyacin da suke dole da shi don gina takaitaccen tsakiyar takaice. Wannan takaitaccen tsakiyar takaice yana da ƙarin wavelength spectrum da earlier discussed technologies.

Blue LED and Quantum Dots

A wannan hanyoyi, an amfani da blue LED don shahara quantum dots. Quantum dots suna da ƙarin lasirin ranar ƙarin da 2 zuwa 10 nm. Suna da tsari ga 10–50 atom. Idan quantum dots suna amfani da blue LED, suka gina thin layer of nano-crystal particles wanda suka da 33 ko 34 pairs of cadmium ko selenium wanda suka kafa a kan LED. Blue light da LED yake gina yana shahara quantum dots. Wannan shahara yana ba da shahara takaitaccen tsakiyar takaice wanda yake da wavelength spectrum ƙarin sama da takaitaccen tsakiyar takaice da ultraviolet LED tare da RGB phosphors yake gina.

Colour Mixing

Multiple LEDs (generally emitting the primary colors red, blue and green) are fitted inside a lamp and the intensity of each LED is tuned proportionately to obtain white light. This is the basic idea of colour mixing technique. Colour mixing technique requires minimum two LEDs in conjunction, emitting blue and yellow light, whose intensities are to be varied in order to generate white light. Color mixing is also done using four LEDs where RED, BLUE, GREEN, and YELLOW are used side by side. As phosphors are not used in color mixing, there is no loss of energy during the conversion process and therefore, color mixing technique is more efficient than wavelength conversion techniques.

Homo-epitaxial ZnSe

Sumitomo Electric Industries, Ltd., Osaka, Japan, teamed with Procomp Informatics, Ltd., Taipei, Taiwan under a joint venture that was named Supra Opto, Inc. to develop and commercialise a new technology for white light production from LED. This new technology is known as Homo-epitaxial ZnSe technology of white light production.

In this technology, white light is generated by growing an epitaxial blue LED layer on a zinc selenide (ZnSe) substrate. This results in the simultaneous emission of blue light from the active region and yellow light from the substrate. The epitaxial layer of the LED emitted a greenish blue light at 483 nm, whereas the ZnSe substrate simultaneously emitted an orange light at 595 nm. The combination of this greenish blue light of wavelength 483 nm and orange colour light of wavelength 595 nm produces a white light and we get a white LED whose correlated colour temperature (CCT) is in the range of 3000 K and above. The average life of this white LED is around 8000 hours.

Presently, this LED is used in applications such as lighting, indicators, and back-lights for liquid crystal displays. However, with the increase in its average life, this white LED will become suitable for additional lighting applications.