CN1680512A - Phosphor powder formulation suitable for low operating voltage electron beam excitation and preparation method thereof - Google Patents

Abstract

The invention discloses a fluorescent powder formula suitable for low operating voltage electron beam excitation and a preparation method thereof₁₀O₁₇The material has the advantages of high light color purity, high stability and the like, the ratio of doping elements can be changed to adjust the light color of the phosphor, in addition, the formula disclosed by the invention can utilize various synthetic methods, such as a solid state reaction method, a coprecipitation method, a gel method or a microemulsion method to prepare single-phase powder, and the preparation method is simple and easy to produce in large quantities, and the obtained finished product has industrial utilization value.

Description

Fluorescent powder formulation suitable for low operating voltage electron beam excitation and its preparation method

technical field

The present invention relates to a fluorescent powder formula suitable for low operating voltage electron beam excitation and its preparation method, in particular to a fluorescent powder suitable for field emission displays, various photoelectric tubes excited by electrons and plasma, and light sources. Powder formulation and preparation method thereof.

Background technique

Displays are becoming more and more important in today's life. In addition to computers or networks, televisions, mobile phones, personal digital assistants (PDAs), and vehicle information systems all need to be controlled or transmitted through displays. For reasons of weight, volume, and health, products are adopting flat panel displays at an increasing rate. In 1999, the global flat-panel display market was approximately US$18.5 billion. This huge growth should be attributed to the good functions and low prices of liquid crystal displays (LCDs). Other flat panel displays (flat panel displays; FPDs) are in the stage of active development, and their uses include large-size home audio-visual equipment such as plasma (plasma) and projection, as well as mobile phones and digital cameras with a larger market. It is expected to surpass and replace liquid crystal displays in price and performance. The characteristic requirements of future displays lie in small size, power saving, high resolution, and rapid response, while in terms of preparation, high pass rate and easy mass production are required.

Among many display technologies, Field Emission Display (FED) is claimed to be the new technology that has the best chance of replacing LCD. The technical principle of the FED is very similar to the traditional cathode-ray tube (cathode-ray tube; CRT), and the FED is a thin cathode-ray tube. In terms of structure, CRT uses a single electron gun to emit electron beams to hit the phosphor panel, and uses a deflection plate to control the direction of the electron beams, while FED has no deflection plate, and each pixel is completed by an electron emitting tip. The entire FED consists of It consists of hundreds of thousands of active cold emitters. Although FED is similar to a thin CRT in appearance, the working voltage of FED (≤1kV) is much lower than that of CRT (15-30kV).

The first proposed field emission principle is called Spindt type micro-sized array, and each unit in the array includes a tiny circular hole and a metal cone in it. However, the lithography technology required to make round holes on the substrate and the size limitation of the evaporation technology for making metal cones both limit the size of the finished display (400mm per side), and the production cost is high. In addition, the tips of Spindttype field emitters are also prone to wear and tear to reduce lifetime. In addition to the Spindt type field emitter, the industry is looking for other alternative technologies with excellent characteristics, easy mass production, and low price. Early literature showed that diamond-structured carbon was used as a field emitter, and the required activation voltage was extremely small. Subsequent studies found that nanostructured graphite or carbon nanotubes were also good field emission materials, and carbon nanotubes (CNT) The features are particularly notable and have the greatest chance of commercialization.

Another important part of the carbon nanotube field emitter (CNT-FED) is the fluorescent material layer. The characteristics of the fluorescent material layer will determine the light color and light emission efficiency of the field emitter, which has considerable research and development value, and currently Phosphor powder research in this area is still in its infancy in the world. In terms of related patents, South Korea's Samsung has applied for more than ten patents on low operating voltage phosphors since 1998, and disclosed a variety of phosphor formulations in the patents, and all said that the phosphors are used in FED. With the advantage of high efficiency, including ZnS, (Zn, Cd)S, ZnS:Zn, ZnS:Ag, (Zn, Cd)S:Ag, Cl, ZnGa ₂ O ₄ , ZnGa ₂ O ₄ :Bi, SrTiO ₃ : RE (RE is a rare earth element) and Y ₂ SiO ₅ and other phosphors (such as US Patent No. 5068157, 6152965, 6322725, 6416688, 6440329, 6641756, and 2003197460, European Patent No. 0882776, and 1052276, and French Patent No. 2800509). In addition, Futaba DenshiKoggo of Japan has also applied for several patents on low operating voltage phosphors. The phosphors are SrTiO ₃ : Pr, ZnGa ₂ O ₄ : Li, P, (Zn, Cd) S: Ag, Cl, and La ₂ O ₂ S: RE (RE is a rare earth element), phosphor (such as US Patent No. 5619098, 2002057229 and Taiwan Patent No. 464902).

The phosphors used in commercialized FEDs are roughly P22 series phosphors, among which the blue phosphors are ZnS:Ag, Cl, the green phosphors are ZnS:Cu, Au, Al, and the red phosphors The body is Y ₂ O ₂ S:Eu. These phosphors are all phosphors used in cathode ray tubes. In order to make FED have a low operating voltage, these phosphors are not covered with aluminum layer like CRT when applied to FED, which will easily lead to deterioration and pollution of phosphors. Field emission sources, reduced vacuum, etc. will affect the lifespan, and the P22 series phosphors contain sulfur, which is less stable to the environment and climate than oxides, and it is easy to shorten the lifespan of the FED. In addition, the phosphors used in these CRTs have poor luminous efficiency when impacted by low-energy electrons.

In view of the above shortcomings, current research directions of all parties are directed towards oxide fluorescent materials that can be excited by low operating voltage, and are committed to improving the luminous intensity of oxide fluorescent materials so that they can be applied to the FED industry.

Contents of the invention

The object of the present invention is to provide a kind of fluorescent material, its main crystal lattice is BaMgAl ₁₀ O ₁₇ oxide, doped with europium ions or doped with europium and manganese ions at the same time, can get blue or blue-green after being excited by electron beams. fluorescent. Its light color is pure and its luminous intensity is high, and its structural stability is higher than that of sulfide. In addition to being suitable for fluorescent materials for FEDs, it can also be used in various electronic devices due to its pure light color and high luminous intensity. , Plasma-excited photocells and fluorescent materials for light sources.

That is, the present invention achieves the above-mentioned purpose through the following technical means; it includes:

A fluorescent powder formula with BaMgAl ₁₀ O ₁₇ as the main lattice, which can produce blue or blue-green fluorescence when excited by a low-voltage excitation source. The main lattice material formula is (Ba _1-x Eu _x ) MgAl ₁₀ O ₁₇ or (Ba _1-x Eu _x )(Mg _1-y Mn _y )Al ₁₀ O ₁₇ (0.0001≤x≤0.5 and 0.0001≤y≤0.5 or 0.05≤x≤0.2 and 0.05≤y≤0.2) , the host lattice material formula is synthesized by a solid-state reaction method, and the preparation method of the phosphor powder formula includes the following steps:

Mixing of raw materials: the raw materials include barium, europium, magnesium, manganese, and aluminum elements, which are reduced from their metal oxides or their salts, and then composed of one or more compounds of barium compounds, europium compounds, magnesium compounds, and manganese compounds , and aluminum compounds for sintering;

Sintering: pre-sintering at a temperature of 1400-1800°C for 6-24 hours in a reducing gas environment (mixed gas environment such as hydrogen)

The host lattice material formulation can also be formed by a combination of coprecipitation, gelation, or microemulsion methods.

The low-voltage excitation source is selected from carbon nanotube emitter (CNT), surface conduction electron emitter (SED), impact surface electron source (ballistic electron surface emitter; BSD), and metal insulator emitter. (metal insulator metal emitter; MIM) and other groups of electronic excitation sources; the voltage of the excitation source is ≤ 1kV, and the excitation source is a plasma excitation source.

Description of drawings

Part (a) in Fig. 1 is the X-ray powder diffraction pattern of the (Ba _1-x Eu _x )MgAl ₁₀ O ₁₇ (x=0.1) sample prepared according to the embodiment of the present invention.

Part (b) in Fig. 1 is the X of the (Ba _1-x Eu _x )(Mg _1-y Mn _y )Al ₁₀ O ₁₇ (x=0.1, y=0.08) sample prepared according to the embodiment of the present invention Light powder diffraction pattern.

Part (c) in Figure 1 is the standard X-ray powder diffraction pattern of BaMgAl ₁₀ O ₁₇ .

Figure 2 is (a) (Ba _1-x Eu _x )MgAl ₁₀ O ₁₇ (x=0.1) and (b) (Ba _1-x Eu _x )(Mg _{1- y} Mn _y ) Light emission spectrum of Al ₁₀ O ₁₇ (x=0.1, y=0.08) sample.

FIG. 3 is a CIE chromaticity coordinate diagram that calibrates the light emission spectrum of FIG. 2 .

Detailed ways

Embodiment one:

Mix 0.6274 grams of barium oxide (BaO), 0.800 grams of europium oxide (Eu ₂ O ₃ ), 0.1833 grams of magnesium oxide (MgO), and 2.3173 grams of aluminum oxide (Al ₂ O ₃ ) (that is, according to (Ba _0.9 Eu _0.1 ) MgAl The ratio of ₁₀ O ₁₇ ) is fully mixed, ground and mixed thoroughly with a mortar, and the uniform mixture is placed in an alumina crucible, and then the alumina crucible is placed in a high-temperature furnace and pre-sintered at 1650°C for 12 hours in a reducing atmosphere. The heating and cooling rates of the sintering process were both 5°C/min. After sintering, it is ground with a mortar to make it into a powder with uniform particles, and the finished product is obtained.

Embodiment two:

1.8947 grams of barium oxide (BaO), 0.2416 grams of europium oxide (Eu ₂ O ₃ ), 0.5091 grams of magnesium oxide (MgO), 7.0000 grams of aluminum oxide (Al ₂ O ₃ ), and 0.1263 grams of manganese carbonate (MnCO ₃ ) ( That is, according to the ratio of (Ba _0.9 Eu _0.1 ) (Mg _0.92 Mn _0.08 ) Al ₁₀ O ₁₇ ) mixed thoroughly, ground and mixed thoroughly with a mortar, put the uniform mixture in an alumina crucible, and then put the alumina crucible into The high-temperature furnace was pre-sintered at 1650°C for 12 hours in a reducing atmosphere, and the heating and cooling rates during the sintering process were both 5°C/min. After the sintering is completed, it is ground with a mortar to make it into a powder with uniform particles, and the finished product is obtained.

(Ba _1-x Eu _x )MgAl ₁₀ O ₁₇ (x=0.1) and (Ba _1-x Eu _x )(Mg _{1-y Mny} )Al ₁₀ O ₁₇ (x=0.1) prepared according to the embodiment of the present invention , y=0.08) sample, its crystal phase purity was identified by X-ray powder diffractometer, the results are shown in (a) and (b) in Figure 1. Compared with the X-ray powder diffraction pattern of the standard BaMgAl ₁₀ O ₁₇ compound (JCPDS no: 26-0163) in (c) in Figure 1, it can be known that the phosphor disclosed by the present invention is a single phase with a hexagonal lattice ( hexagonal), its lattice constants are a=b=5.62 Å, c=8.781 Å; α=β=90°, γ=120°.

Figure 2 shows (Ba _1-x Eu _x )MgAl ₁₀ O ₁₇ (x=0.1) and (Ba _1-x Eu _x )(Mg _{1-y Mny} )Al ₁₀ O ₁₇ ( x=0.1, y=0.08) Light emission spectrum diagram of the sample. It can be seen from the results that the two phosphors emit blue and blue-green fluorescence when excited by a low-voltage electron beam. The data of the emission spectrum are converted into the chromaticity coordinates represented by the phosphor with the formula of the chromaticity diagram formulated by the International Commission on Illumination (Commission Internationale de l'Eclairage, CIE) in 1931, which is marked in image 3. It is equivalent to the blue light of x=0.1481 and y=0.0659 and the blue-green light of x=0.1470 and y=0.2777. It is known from the chromaticity coordinate diagram that fixing the content of europium and increasing the content of manganese will make the light color of the phosphor natural. The blue moves to the green range, and the luminescent color of the phosphor can be changed by changing the concentration of dopant ions.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims (15)

1. the fluorescent powder of a suitable low operating voltage electron-beam excitation is filled a prescription, with BaMgAl ₁₀O ₁₇Be host lattice, excited by the low voltage excitaton source and can produce blue or glaucous fluorescent.

2. the fluorescent powder prescription of suitable low operating voltage electron-beam excitation according to claim 1 is characterized in that described BaMgAl ₁₀O ₁₇Be host lattice, material prescription is (Ba _1-xEu _x) MgAl ₁₀O ₁₇Or (Ba _1-xEu _x) (Mg _1-yMn _y) Al ₁₀O ₁₇, 0.0001≤x≤0.5 and 0.0001≤y≤0.5 wherein.

3. the fluorescent powder prescription of suitable low operating voltage electron-beam excitation according to claim 1 is characterized in that described BaMgAl ₁₀O ₁₇Be host lattice, material prescription is (Ba _1-xEu _x) MgAl ₁₀O ₁₇Or (Ba _1-xEu _x) (Mg _1-yMn _y) Al ₁₀O ₁₇, 0.05≤x≤0.2 and 0.05≤y≤0.2 wherein.

4. the fluorescent powder prescription of suitable low operating voltage electron-beam excitation according to claim 1 is characterized in that described BaMgAl ₁₀O ₁₇Be host lattice, material prescription is formed by coprecipitation method.

5. the fluorescent powder prescription of suitable low operating voltage electron-beam excitation according to claim 1 is characterized in that described BaMgAl ₁₀O ₁₇Be host lattice, material prescription is formed by gel method.

6. the fluorescent powder prescription of suitable low operating voltage electron-beam excitation according to claim 1 is characterized in that described BaMgAl ₁₀O ₁₇Be host lattice, material prescription is formed by the microemulsion method.

7. the fluorescent powder of suitable low operating voltage electron-beam excitation according to claim 1 prescription, it is characterized in that described low voltage excitaton source be selected from CNT (carbon nano-tube), surface conductance electron source, impact type surface electrical component, and metal insulator emissive source etc. electron excitation source in groups.

8. the fluorescent powder of suitable low operating voltage electron-beam excitation according to claim 1 is filled a prescription, and it is characterized in that the voltage≤1kV of described excitaton source.

9. a preparation method who fills a prescription in order to the fluorescent powder of making suitable low operating voltage electron-beam excitation according to claim 1 is characterized in that described BaMgAl ₁₀O ₁₇Be host lattice, material prescription is synthetic by solid state reaction, and it comprises the following steps:

A. raw material mixes;

B. sintering: need in the reducing gas environment, carry out presintering 6～24 hours with 1400～1800 ℃ of temperature.

10. preparation method according to claim 9 is characterized in that it is to form (Ba that described raw material mixes _1-xEu _x) MgAl ₁₀O ₁₇Or (Ba _1-xEu _x) (Mg _1-yMn _y) Al ₁₀O ₁₇Prescription, comprising barium, europium, magnesium, manganese and aluminium element, the source is to be selected from its metal oxide or its esters, carries out sintering again in reducing environment.

11. preparation method according to claim 10, it is characterized in that described barium compound, europium compound, magnesium compound, manganic compound, and aluminum compound formed by one or more compounds.

12. preparation method according to claim 9 is characterized in that best sintering is to carry out presintering 10～15 hours under 1400～1800 ℃ of reducing gas environment, temperature.

13. preparation method according to claim 9 is characterized in that another best sintering is to carry out presintering 10～15 hours under 1500～1700 ℃ of reducing gas environment, temperature.

14. preparation method according to claim 9, the reducing environment when it is characterized in that sintering mix the mixed-gas environment of hydrogen nitrogen.

15. preparation method according to claim 9 is characterized in that described BaMgAl ₁₀O ₁₇Be host lattice, material prescription is the method for making formation by one of group that is selected from coprecipitation method, gel method and microemulsion method.