Patent Application
20130009097
1. Fields of the Invention
The present invention relates to a phosphor and a method of manufacturing the same, especially to an oxynitride phosphor and a method of manufacturing the same.
2. Descriptions of Related Art
For energy savings, carbon reduction, and environment protection, conventional light sources are gradually replaced by white-light LED (light emitting diode)-based lighting in developed countries. The LED features on compact size, low power consumption, long life time, low heat emission, and short reaction time. LED is easy to install in equipment, of low heat radiation, and used for high frequency operation and over 100 thousand hours. It uses only one-eighths or one-tenths power in comparison with conventional light bulbs and a half power compared with fluorescent lights. LED overcomes a plurality of shortcomings of incandescent bulbs. Thus the white light LED is a new light source for illumination and displays of the 21st century. It is called green light source due to its features of energy saving and environment protection.
Refer to U.S. Pat. No. 5,998,925 applied by Japanese Nichia Corporation filed in 1996, a light emitting diode (LED) includes a semiconductor element emitting blue light and a phosphor activated with cerium. The phosphor is Cerium-doped yttrium aluminum garnet (YAG:Ce) that emits yellow light. Thus the LED emits white light by blending the blue light and the yellow light emitted by the phosphor. Although the nitride phosphors available now are of better thermal resistance and water resistance, its cost is high. The cost of oxide phosphors is low yet it has poor thermal stability and poor water resistance. Thus oxynitride phosphors have received considerable attention compared to the existing nitride and oxide phosphors. The precursor for synthesis of the oxynitride phosphors does not include nitride with extreme air-sensitivity. The synthesis temperature is reduced by using a part of oxides. Moreover, the oxynitride phosphors have good stability similar to that of the nitrides. The oxynitride phosphors have advantages of both oxides and nitrides. Thus a plurality of oxynitride phosphors including β-SiAlON, MSi2O2N2 (M=Ca, Sr, Ba), etc. has been developed recently.
As to the oxynitride phosphor MxAyBzOuNv (0.00001≦y≦3; 0.00001≦z≦6; 0.00001≦u≦12; 0.00001≦v≦12; 0.00001≦x≦5), M is a single active center or a mixture of active centers. A is a bivalent element or a mixture of a plurality of bivalent elements. B can be a trivalent element, a tetravalent element, a mixture of a plurality of trivalent elements or a mixture of a plurality of tetravalent elements. O is a univalent element, a bivalent element, a mixture of a plurality of univalent elements, or a mixture of a plurality of bivalent elements. N is a univalent element, a bivalent element, a trivalent element, a mixture of a plurality of univalent elements, a mixture of a plurality of bivalent elements, or a mixture of a plurality of trivalent elements. This chemical formula has been developed and patented by OSRAM GESELLSCHAFT MIT BESCHRÄNKTER HAFTUNG in 2008 with Pat. App. No. PCT/EP2008/059726 and the title is “TEMPERATURE-STABLE OXYNITRIDE PHOSPHOR AND LIGHT SOURCE COMPRISING A CORRESPONDING PHOSPHOR MATERIAL”. However, the patent doesn't disclose that this formula is able to be synthesized under high pressure.
In 2009, Mitsubishi Chemical Corporation has also applied for the patent with Pub. No. WO/2009/017206, App. No. PCT/JP2008/063802 filed on Jul. 31, 2008 and the title is “PHOSPHOR AND METHOD FOR PRODUCING THE SAME, CRYSTALLINE SILICON NITRIDE AND METHOD FOR PRODUCING THE SAME, PHOSPHOR-CONTAINING COMPOSITION, LIGHT-EMITTING DEVICE USING THE PHOSPHOR, IMAGE DISPLAY DEVICE, AND ILLUMINATING DEVICE”. A pure product revealed in this patent is synthesized under normal pressure and is obtained by using pre-treated silicon nitride (Si3N4) precursor.
In recent years, light emitting devices with phosphor composition have been applied to backlights. The full width at half maximum (FWHM) of the phosphor required is smaller than 30 nm so that the resolution of the spectrum is improved after passing through a filter. The patents mentioned above don't disclose formula of phosphors whose FWHM is smaller than 30 nm.
Therefore it is a primary object of the present invention to provide an oxynitride phosphor and a method of manufacturing the same. The full width at half maximum (FWHM) of a peak of emission wavelength of the oxynitride phosphor is smaller than 30 nm so that the oxynitride phosphor is applied to backlights.
It is another object of the present invention to provide an oxynitride phosphor and a method of manufacturing the same. The oxynitride phosphor is excited by vacuum ultraviolet light with a wavelength range of 130 nm to 300 nm or light with a wavelength range of 300 nm to 550 nm wavelength range. The emission wavelength of the oxynitride phosphor is ranging from 400 nm to 700 nm. Thus the oxynitride phosphor can be applied to plasma display panels.
It is a further object of the present invention to provide an oxynitride phosphor and a method of manufacturing the same. A precursor is sintered under high pressure and high temperature for synthesis of the oxynitride phosphor. The manufacturing process is simple and the phosphor can be mass-produced.
In order to achieve the above objects, an oxynitride phosphor of the present invention is provided. The general formula of the oxynitride phosphor is Ba3-xSi6O12N2: Yx, wherein x is ranging from 0 to 1 and Y is praseodymium (Pr) or terbium (Tb) used as a luminescent center. The full width at half maximum (FWHM) of a peak of emission wavelength of the oxynitride phosphor is smaller than 30 nm.
A method of manufacturing an oxynitride phosphor of the present invention is provided. And the method includes a plurality of steps. Firstly, provide a precursor and then sinter the precursor by solid-state reaction for synthesis of an oxynitride phosphor. The general formula of the oxynitride phosphor is Ba3-xSi6O12N2: Yx, wherein x is ranging from 0 to 1 and Y is praseodymium (Pr) or terbium (Tb) used as a luminescent center. The full width at half maximum (FWHM) of the oxynitride phosphor is smaller than 30 nm.
The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein
Refer to
Refer to
Refer to
Refer to
Refer to
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative devices shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 100123637 | Jul 2011 | TW | national |
