KR20100111545A - Process for preparing orange color phosphor - Google Patents

Abstract

PURPOSE: A manufacturing method of an orange color phosphor is provided to use the phosphor for a high color rendering illumination by applying a UV excitation light and an AC power source. CONSTITUTION: A manufacturing method of an orange color phosphor comprises the following steps: mixing silver as a main part activator, and copper and aluminum as a collaboration activator, to a zinc sulfide parent(S10); and calcinating the mixture after adding 0.158 parts of AgNO3 by weight, 0.325 parts of Cu by weight, 2.082 parts of Al(NO3)3 by weight, and 0.28 parts of CaO by weight(S30,S40).

Description

Production method of yellow luminescent phosphor {PROCESS FOR PREPARING ORANGE COLOR PHOSPHOR}

The present invention relates to a method of manufacturing a yellow light emitting phosphor, and more particularly, by emitting light to have high color rendering and excellent light emitting luminance by applying UV excitation light and AC power, it is possible to manufacture a yellow light emitting phosphor that can be used for high color rendering. It relates to a manufacturing method.

Phosphor is a material that emits visible light by receiving energy from the outside and is an important material indispensable in photoelectronics. Such phosphors are used to produce LED white light as an information element, and high efficiency LEDs are being widely expanded in the light source field such as backlights of liquid crystal TVs, headlamps of automobiles, and general lighting.

The high efficiency high color rendering LED began replacing the incandescent lamp in 2007, and the currently commercially available white LED converts the blue LED and yellow phosphor into white color, and can use the transmitted light of the blue LED. It has the advantage of converting high efficiency into high efficiency, but this complementary white LED has a shortcoming that it looks dark when seeing an object with red color because of lack of red component among blue, green and red light which are three primary colors of light. Because of its high correlation color temperature (CCT) and low color rendering index (CRI) of about 65-80, eyes are easily tired and natural colors of objects are not properly reproduced, making them unsuitable for general lighting.

Such blue LEDs generally have high efficiency and low color rendering index, and conversely, high color rendering index has low efficiency, which limits the application of LED lighting fixtures.In order to use white LEDs for backlight and lighting, the amount of light of LED white light, Qualitative improvements, such as the range of light shining, the color temperature and color rendering of light, must be made.

In order to improve this, the white LED method using the UV LED chip as an excitation light source can secure excellent color stability by applying a blue, green, and red multilayer phosphor on the chip to have a very broad spectrum, and CCT Since it is possible to control and CRI, it is attracting attention as a next-generation method for realizing a white LED for lighting, and to realize this, it is required to develop phosphors excited by UV and AC power.

Phosphor shows different emission characteristics according to each excitation source. Especially, when the phosphor for cathodeluminescence (CL) is used as the phosphor for electroluminescence (EL), the phosphor does not emit light or is low even if it emits light. Luminance and short half-life are not suitable as phosphors for EL. Combining RGB or RGBOY (red, green, blue, orange, yellow) phosphors with UV LEDs emits multicolored light from the UV-stimulated phosphors and creates a white color with a mixture of emitted multicolored lights. In addition to the free mixing of color temperature and color rendering, the use of a combination of yellow phosphors increases the number of parameters that can be controlled by itself. Therefore, the yellow phosphor has a high color rendering index UV LED device is the core field of the next-generation light source device.

Typical phosphors for CL include YVO ₄ : Eu Y ₂ O ₃ : Eu phosphors, which are rare earths using europium (Eu) as an activator, and have a light emission wavelength range of 611 to 626 nm. Such phosphors are used for color TV (clolor picture tube), monochrome display (monochrome display) and vacuum fluorescent display (vacuum fluorescent display). In order to be applied to the EL, it must have durability and high brightness that can withstand high voltage application, and thus is used only for the display device, and is not applied to the next generation EL device.

As known yellow phosphors, Nemoto's YAG Nemoto-00902 and YAG nemoto-432 have been developed, and the emission wavelength shows a major peak at 570 to 590 nm and has a broad emission spectrum gradually decreasing to 700 nm. In addition, commercially available EL phosphors are yellow ZnS: Mn (Kasei optonix, KX-605A). Inorganic EL phosphors exhibiting good luminescent properties even at low voltages include ZnS in which manganese (Mn) is added as an activator. It has been reported to emit light at direct current and low voltage by adding copper (Cu) and chlorine (Cl) to Mn powder (A Vecht et al 1969 J. Phys. D: Appl. Phys. 2 953-966). The luminescence properties by AC and DC (G.Neunert et al 2003 Acta. Phys. Pol. A vol. 104) have been newly verified, but the emission wavelength is 580nm yellow phosphor.

The present invention relates to a method of manufacturing a yellow light emitting phosphor, and more particularly, to produce a yellow light emitting phosphor that can be used for high color rendering by emitting light to have high color rendering and excellent light emitting brightness by applying UV excitation light and AC power. It is about a method.

The method of manufacturing a yellow light emitting phosphor according to the present invention includes a mixing step of mixing copper (Cu) and aluminum (Al) with a zinc sulfide (ZnS) powder matrix as a main active agent and silver (Ag) as a co-activator, and the mixing step It characterized in that it comprises a firing step of firing the mixture in.

In addition, the method of manufacturing a yellow light emitting phosphor according to the present invention, the firing step is characterized in that it comprises the step of firing the mixture at a temperature of 900 ~ 1200 ℃.

In addition, the method of manufacturing a yellow light emitting phosphor according to the present invention, the mixing step, 0.158 parts by weight of AgNO ₃ , 0.325 g by weight of Cu, 2.082 parts by weight of Al (NO ₃ ) ₃ and CaO with a flux to 1000 parts by weight of ZnS 0.28 parts by weight is added and mixed, and the firing step includes a prefiring step of firing the mixture at a temperature of 500 ° C. in a vacuum state, and a firing of the prefired firing material at a temperature of 900 to 1200 ° C. in a reducing atmosphere. It is characterized in that it comprises a secondary firing step, and the secondary firing step of firing the first fired calcined product to room temperature and then to a temperature of 500 ℃.

According to the above configuration, the method of manufacturing a yellow light emitting phosphor according to the present invention can produce a yellow light emitting phosphor that can be used for high color rendering by emitting light to have high color rendering and excellent light emitting brightness by applying UV excitation light and AC power. That has the advantage.

High color rendering UV LED and EL lighting using the yellow light emitting phosphor produced according to the present invention can reduce the power consumption by 50%, 71% in the electricity bill, 75% in maintenance costs compared to the existing CCFL-type lighting, and adapt The electricity consumption can reduce the cost of about 8 trillion won to maintain the power plant construction.

In addition, UV LED and EL lighting with high color rendering are used to replace neon and incandescent billboards that depend on imports, and can be used as a light source for the advertising market of about 2 trillion won. We expect to see an import replacement effect of W100bn.

Hereinafter, a method of manufacturing a yellow light emitting phosphor according to the present invention will be described in detail with reference to the drawings and examples.

The method of the yellow light emitting phosphor according to the embodiment of the present invention is as follows.

In order to prepare a ZnS: Ag, Cu, Al phosphor according to the present invention, a compound containing Ag as an activator, a Cu-containing compound, and a co-activator as aluminum in the raw material on the parent ZnS powder (Al) is mixed and at least one of CaO, KI and NaI is mixed and added as a flux. AgNO ₃ or Ag ₂ SO ₄ is used as a compound containing Ag as an activator, and Al ₂ (So ₄ ) _{3 ·} 18H ₂ O or Al (NO ₃ ) is used as a compound containing aluminum as a co-activator. _3, aluminum compounds such as 9H ₂ O is used.

After mixing them for 3 to 24 hours, the mixture is placed in an alumina or quartz crucible and a mixture of activated carbon and sulfur is placed on the raw material composition, and then the lid is covered and calcined under a reducing atmosphere of nitrogen or hydrogen. During firing, the temperature increase rate is 2 to 20 ° C / min, and the firing temperature is maintained at 900 ° C to 1200 ° C. The spherical yellow ZnS: Ag, Cu, Al phosphor obtained by the above method has an average particle size of 8 to 20 µm after washing with water, and the color coordinates represented by CIE 1931 have 0.541 to 0.558 and y is 0.450 to 0.461.

Referring to the embodiment shown in Figure 1 will be described in more detail the process for the production of ZnS: Ag, Cu, Al phosphor according to an embodiment of the present invention.

Example 1

1. Mixing step (S10)

The zinc sulfide (ZnS) powder is mixed with silver (Ag) as a main activator and copper (Cu) and aluminum (Al) as a co-activator.

The components for producing the phosphor and the total amount thereof are ZnS: 1000g, AgNO ₃ : 0.158g, Cu: 0.325g, Al (NO ₃ ) ₃ : 2.082g, CaO: 0.28g.

First, an AgNO ₃ silver compound as an activator, copper (Cu), and an Al (NO ₃ ) ₃ 9H ₂ O aluminum compound as a co-activator are mixed, and CaO is added as a flux.

The raw material mixture which mixed the active agent and the flux is mixed using a ball mill.

2. Pre-firing step (S20)

After filling the raw material mixture in a quartz crucible, the raw material mixture is put into a vacuum furnace and baked in an electric furnace at 500 ° C. for at least 1 hour while maintaining a vacuum state using a rotary pump. This is to prevent the phosphor brightness caused by impurities from being lowered by removing moisture and oxygen gases present between the mixed powder particles and to obtain sufficient time for the flux CaO to be stably reacted at an early stage. This is because maintaining the vacuum is much more effective than removing moisture at normal atmospheric pressure. At a temperature of 600 ° C. or higher, CaO, which is a flux, melts to form precipitates, so that it is difficult to obtain an appropriate compound.

3. First firing step (S30)

After the prefiring is finished, the mixture is charged into a heat-resistant crucible, and covered with sulfur (S) powder on top of the mixture, and then capped and calcined at 900-1200 ° C. for 2 to 3 hours under a reducing atmosphere. When the temperature rises above 600 ° C, zinc (Zn) and sulfur (S) in zinc sulfide (ZnS) are separated from sulfur (S) due to different vapor pressures, resulting in the parent zinc sulfide (ZnS). Defects are generated, and it becomes difficult to effectively inject raw materials of platinum (Ag), copper (Cu), and alumina (Al) added as an activator. To prevent this, the sulfur (S) powder is covered to suppress the occurrence of defects of zinc sulfide. After the reaction is completed, the natural cooling to room temperature and ZnS: Ag, Cu, Al yellow phosphor can be obtained.

In this case, when only copper (Cu) is added as an activator, needle-like copper sulfide (Cu _x S) is formed on the surface of zinc sulfide (ZnS), contributing to blue light emission, but added as an activator and coactivator. platinum (Ag) and the alumina (Al) is formed to block the entire instrumentation (electric field) around the Ag ²⁺ ions the rate of diffusion is faster than Cu ²⁺ ions unstable Cu ²⁺ ions, and the Cu ²⁺ ions Zn Interferes with the substitution with ²⁺ ions. The addition of such co-activators has been shown to inhibit local blue light emission by Cu ²⁺ ions. Since, Ag ²⁺ ions are here (excite) emission of a photon (photon) in the state transition copies (radiative transitions) the sural sacheon the (non-radiative transitions) resulting in a fully implanted Ag ²⁺ ions, not to lose energy Is shown to contribute to luminescence by excitating holes bound to Cu ²⁺ and A1 ²⁺ ions without losing energy.

4. Second firing step (S40)

In order to improve the characteristics of the synthesized spherical yellow phosphor, it is cooled to room temperature and then reheated in a secondary firing step. N ₂ + H ₂ (10%) was reheated at 800 ° C. for 5 hours / min. This is because the work for activating the already produced compound interferes with the role of the active agent due to the increase of defects due to oxygen vacancy in ZnS. This results in a different energy level (complex defect) due to different impurities than when oxygen is substituted at the position of the Zn atom of the ZnS compound. Particularly, in the case of platinum (Ag), as the melting temperature is higher than 1700 ° C. and the temperature is increased, the absorption of hydrogen and oxygen is increased, thereby acting as a main cause of the redox reaction. In order to remove this, it is possible to increase the luminance of the phosphor by adding nitrogen (N ₂ ), which is an inert gas, and reactive gas (H ₂ ) to remove oxygen pores present in ZnS by reacting with hydrogen.

5. Classification step (S50)

Finally classify the completed firing. In general phosphor preparation, it is necessary to wash and dry to remove the flux and reactant remaining after firing, but the CaO flux added in the present invention does not need to be removed with the reactant, thereby obtaining a high purity compound.

6. Results

FIG. 2 is a graph illustrating color coordinates by UV excitation of a yellow light emitting phosphor manufactured according to the first embodiment. Referring to FIG. 2, the ZnS: Ag, Cu, Al yellow phosphor has a color coordinate of CIE x = 0.543 and y = 0.454.

3 is a graph illustrating the light emission wavelength of the yellow light-emitting phosphor prepared according to the first embodiment. Referring to FIG. 3, the yellow light emitting phosphor according to the present invention exhibited a wavelength of 575 nm in the yellow region due to excitation by UV wavelength in the 337 nm band using a nitrogen (N ² ) laser.

4 is a graph illustrating an EL device structure. Referring to Figure 4, a thin transparent PET film 5 made on the back electrode (4), titanium barium oxide (BaTiO ₃₎ made of tin oxide (ITO) having a 0.1㎛ thickness of the first insulating layer 3, and The light emitting layer 2, which is a phosphor (ZnS: Ag, Cu, Al) having a thickness of 3 mu m, was applied, and composed of a transparent electrode 1 made of 0.2 mu m tin oxide (ITO). The yellow band of 575nm was obtained by applying AC voltage of 400hz and 250V to the device thus constructed.

Hereinafter will be described in preparation for a specific embodiment of the yellow light emitting phosphor according to the present invention.

Example 2

<Control 1>

As in Example 1, 0.158 g of AgNO ₃ was added to 1000 g of powdered ZnS (manufactured by Sakai Co., Ltd.), and 2.082 g of Al (N0 ₃ ) ₃ and 0.325 g of Cu were added as a co-activator, followed by wet mixing. The mixture was calcined under a reducing atmosphere for 2 hours to prepare a phosphor, and the thus prepared phosphor was washed several times to obtain a finished product.

<Control 2>

The yellow phosphor was prepared in the same manner as in Control 1 except that AgNO ₃ and Al (N0 ₃ ) _{3 were} changed in a 1: 5 molar ratio. Table 1 shows the luminescence properties of the phosphors according to the above embodiments.

<Control Group 3>

The yellow phosphor was prepared by the same method as in Control 1 but changing the AgNO ₃ and Al (N0 ₃ ) ₃ changes in a 1: 2 molar ratio. Table 1 shows the luminescence properties of the phosphors according to the above embodiments.

<Control 4>

The yellow phosphor was prepared in the same manner as in Control 1 except that AgNO ₃ and Al (N0 ₃ ) _{3 were} changed in a 2: 1 molar ratio. Table 1 shows the luminescence properties of the phosphors according to the above embodiments.

<Control 5>

The yellow phosphor was prepared in the same manner as in Control 1 except that AgNO ₃ and Al (N0 ₃ ) _{3 were} changed in a 4: 1 molar ratio. Table 1 shows the luminescence properties of the phosphors according to the above embodiments.

1Khz, 600V CIE x CIE y cd / m ² Control 1 0.54 0.45 300
Control 2 0.55 0.46 240
Control 3 0.51 0.43 180
Control 4 0.50 0.44 90
Control group 5 0.49 0.48 34

As can be seen from Table 1, it can be seen that the luminance and color coordinates due to UV excitation light are changed according to the mixing ratio of the activator and the coactivator.

As can be seen in FIG. 2, the yellow light-emitting phosphor (control 1) according to the present invention can be seen that the color coordinate is CIE x = 0.5433 y = 0.4540 (coordinate indicated by reference numeral 1), as can be seen from FIG. The yellow light-emitting phosphor according to the present invention can be obtained from the AC power supply and UV excitation, so that it is possible to obtain a high luminance of 575 nm wavelength.

As described above, the ZnS: Ag, Cu, Al phosphors according to the present invention exhibit excellent emission peaks by UV-excited light, and thus have no practical difficulty and obtain yellow phosphors that operate under high current density and emit high luminance. The phosphor of the present invention can be said to be very valuable in practical terms.

The manufacturing method of the yellow light-emitting phosphor described above and shown in the drawings is only one embodiment for carrying out the present invention, and should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is defined only by the matters set forth in the claims below, and the embodiments which have been improved and changed without departing from the gist of the present invention will be apparent to those skilled in the art. It will be said to belong to the protection scope of the present invention.

1 is a flowchart illustrating a manufacturing process of a yellow light emitting phosphor according to an embodiment of the present invention.

Figure 2 is a graph showing the color coordinates of the yellow light-emitting phosphor according to the UV excitation light according to an embodiment of the present invention

3 is a graph showing the light emission wavelength of a yellow light emitting phosphor according to an embodiment of the present invention

4 is a cross-sectional view showing the structure of a lighting apparatus using a yellow light-emitting phosphor according to an embodiment of the present invention

Claims (3)

A mixing step of mixing zinc sulfide (ZnS) powder matrix with silver (Ag) as a main activator and copper (Cu) and aluminum (Al) as a co-activator; And a firing step of firing the mixture in the mixing step. The method of claim 1, The firing step includes the step of firing the mixture at a temperature of 900 ~ 1200 ℃ method of producing a yellow light emitting phosphor. The method of claim 1, In the mixing step, 0.158 parts by weight of AgNO ₃ , 0.325 g by weight of Cu, 2.082 parts by weight of Al (NO ₃ ) ₃ , and 0.28 parts by weight of CaO are added and mixed with the flux, The firing step may include a pre-firing step of firing the mixture at a temperature of 500 ° C. in a vacuum state, and a first firing step of firing the fired product pre-fired in a reducing atmosphere at a temperature of 900 to 1200 ° C., and primary firing. And a secondary firing step of cooling the calcined product to room temperature and then calcining at a temperature of 500 ° C.

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