KR20140109233A - Method of producing phosphor coated with glass using glass firt and white LEDs comprising the phosphor coated with glass - Google Patents

Abstract

The present invention relates to a method of producing a glass-coated phosphor using a glass frit, a glass-coated phosphor prepared by the same method, and a white light-emitting device comprising the phosphor. The method of producing a glass-coated phosphor includes the steps of: preparing a mixture in which the glass frit and the phosphor are mixed; preparing a pellet via the prepared mixture; preparing a plate by performing a heat-treatment of the pellet; and obtaining the glass-coated phosphor by crushing the plate. Thus, a glass-coated phosphor having improved water stability and thermal stability can be provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a glass-coated phosphor using glass frit, a method of manufacturing a phosphor using the phosphor,

The present invention relates to a method of manufacturing a glass-coated phosphor using glass frit, a glass-coated phosphor by the method, and a white light-emitting device including the phosphor.

Recently, researches on LEDs (Light Emitting Diodes) having high efficiency and environment-friendly advantages have been actively conducted in order to overcome the environmental crisis such as the energy crisis and / or global warming. In order to be used as a solid light source to replace LEDs, fluorescent lamps, incandescent lamps and LCD backlight units having excellent advantages, it is most important to realize white light. In connection with this, phosphors which are precision ceramic materials are indispensable for realizing white light using LED It is a key material.

Since the high-brightness blue LED chip was commercialized in 1993, the blue light emitted from the blue LED and a part of the blue LED were combined to form a Y ₃ Al ₅ O ₁₂ : Ce ³⁺ (YAG: White light emitting diodes (LEDs) emit white light using yellow light (560 nm) obtained by exciting a Ce phosphor. Since then, due to the patent problem of white LED using YAG: Ce phosphor, a silicate yellow phosphor has been developed and used in manufacturing white LED. White light using YAG: Ce or silicate phosphor exhibits good efficiency, but it is difficult to mass-produce white LEDs having the same color coordinates due to color separation due to a wide wavelength interval between blue and yellow. Also, it is not easy to control important color temperature and color rendering index in illuminating light source.

In order to overcome this problem, attempts have been made to improve the color rendering property by using red phosphors such as SrS: Eu ²⁺ and CaS: Eu ²⁺ , but sulfide phosphors are applied to white LEDs . In addition, in addition to these characteristics, silicate-based LEDs suffer from thermal quenching due to heat due to ambient temperature, making it difficult to manufacture reliable white LEDs. Therefore, while the development of a new phosphor is urgently required, there is a need for a technique capable of improving the disadvantages of using a conventional phosphor.

In the meantime, Xiaoxia Ju et al., Journal of Solid State Chemistry 187, pp109-113, 2012) and Zhenhe Xu et al. (Zhenhe Xu et al., Journal of Solid State Chemistry 196, pp301-308, 2012) coating the phosphor with SiO ₂ and discloses on how to improve the stability of the phosphor, etc. So-Ra Gang phosphor using the TiO ₂ (So-Ra Gang et al. , Microelectronics reliability 52, pp2174-2179, 2012) Of the present invention. In addition, there are methods for improving the stability of the phosphor by using Al ₂ O ₃ , ZnO, and ZrO ₂ in order to improve the stability of the phosphor. However, there has not been reported a document that improves the stability of the phosphor using glass frit have.

Accordingly, an object of the present invention is to provide a method of manufacturing a glass-coated phosphor using glass frit, a glass-coated phosphor by the method, and a white light emitting device including the phosphor.

Another object of the present invention is to provide a method of manufacturing a glass-coated phosphor using glass frit capable of improving moisture and thermal vulnerability of the phosphor, a method of manufacturing a glass- .

According to an aspect of the present invention, there is provided a method of manufacturing a glass-coated phosphor, the method comprising: preparing a mixture of glass frit and phosphor; Preparing pellets with the prepared mixture; Subjecting the pellet to a heat treatment to produce a plate; And grinding the plate to obtain a glass-coated phosphor.

In the preparation of the mixture, the glass frit may be mixed at 10 to 80 wt% and the phosphor at 20 to 90 wt% with respect to the whole mixture.

The heat treatment may be performed at 600 to 800 ° C for 1 to 12 hours.

Further, the above object can be achieved by the glass-coated phosphor produced by the above-described production method according to the present invention.

The above object can also be achieved by a white light emitting device comprising a glass-coated phosphor produced by the above-described manufacturing method according to the present invention.

According to the present invention, it is possible to provide a phosphor in which the glass is stuck to the phosphor and moisture and thermal stability of the phosphor having moisture and heat vulnerability are improved.

Further, according to the present invention, it is possible to provide a white light emitting device including a phosphor coated with glass having improved stability.

1 shows the results of PL intensity measurement of a glass-coated phosphor prepared according to an embodiment of the present invention,
2A and 2B are SEM photographs of a glass-coated phosphor prepared according to an embodiment of the present invention,
FIG. 3 and FIG. 4 show the PL intensity measurement results before and after moisture exposure of the glass-coated phosphor prepared according to one embodiment of the present invention,
5 is a graph showing PL intensity measurement results before and after moisture exposure of a glass-coated phosphor prepared according to another embodiment of the present invention,
6 and 7 show the effect of the pellet process on the PL intensity of the phosphor,
8 shows the TQ measurement results of the glass-coated phosphor prepared according to the present invention and the control group,
9 and 10 show EL measurement results of the glass-coated phosphor prepared according to the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

The present invention provides a method for producing a glass-coated phosphor, comprising the steps of: preparing a mixture of glass frit and phosphor; Preparing pellets with the prepared mixture; Subjecting the pellet to a heat treatment to produce a plate; And grinding the plate to obtain a glass-coated phosphor.

In the preparation of the mixture, the glass frit may include glass frit of any known composition, and preferably glass frit having the following formula (1) may be used.

[Chemical Formula 1]

SiO ₂ -B ₂ O ₃ -RO (R = Ba, Zn, Mg)

In the step of preparing the mixture, the phosphor may include a phosphor of any known composition, and preferably a phosphor of the following formula (2) may be used.

(2)

Sr _2.95 Al _0.5 Si _0.5 O _4.5 F _0.5 : Ce

In the step of preparing the mixture, the glass frit may be mixed with 10 to 80 wt% and the phosphor may be mixed with 20 to 90 wt% with respect to the whole mixture. The glass frit may be mixed in an amount of 20 to 60 wt%, and the phosphor may be mixed in an amount of 40 to 90 wt%.

The mixture is agitated so that the glass frit and the phosphor are mixed well so that the phosphor is well dispersed in the glass.

Further, the present invention includes a step of producing pellets from the mixture. It is generally known that phosphors and glass do not stick together. Therefore, when the glass powder and the phosphor are simply mixed and heat-treated, there arises a problem that the glass is not properly coated on the phosphor. In order to solve this problem, in the present invention, pellets are prepared before mixing glass frit and phosphor and then heat treatment. So that the phosphor and the glass frit are adhered to each other by the pellet.

The present invention also includes a step of performing heat treatment on the pellet to produce a plate.

The heat treatment may be carried out at 600 to 800 ° C for 1 to 12 hours under a reducing atmosphere or an atmospheric environment, as the case may be. The conditions of the heat treatment may be different depending on the conditions of the glass frit.

The plate produced after the heat treatment may be pulverized to obtain a phosphor coated with glass in powder form.

According to the manufacturing method of the present invention, a phosphor coated with glass can be obtained, and a phosphor having improved moisture and thermal stability can be provided.

Accordingly, the present invention provides a glass-coated phosphor produced by the above-described production method, and further provides a white light-emitting device including the above-prepared glass-coated phosphor. The white light emitting device can be used as various high efficiency white light sources such as light emitting diodes, laser diodes, surface emitting laser diodes, inorganic electro luminescence devices, and organic electroluminescence devices.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples.

EXAMPLE 1 Preparation of Glass-Coated Phosphor 1

Glass frit consisting of SiO ₂ -B ₂ O ₃ -RO (R = Ba, Zn, Mg) and Sr _2.95 Al _0.5 Si _0.5 O _4.5 F _0.5 : Ce phosphor were used to form a glass frit: %) 8: 2, 7: 3, and 6: 4 ratios, respectively, and pellets were prepared, and plates were prepared after heat treatment at about 600 ° C. The plate was pulverized to obtain a glass-coated phosphor according to each mixing ratio.

Example 2: Preparation of glass-coated phosphor 2

The glass frit and the phosphor were mixed in the same manner as in Example 1 except that GTP (wt%) was used in the ratio of 8: 2, 7: 3, 6: 4, 5: 5, 4: 6, 3: To obtain a glass-coated phosphor.

Experimental Example 1. PL intensity test of the phosphor of Example 1

The PL intensity (photoluminescence intensity) of each of the glass-coated phosphors prepared in Example 1 in which the mixing ratio of glass frit and phosphor was different was measured by a known method.

The results are shown in Fig. Referring to FIG. 1, it was confirmed that as the ratio of the phosphor increases at each of? _Ex 450nm and? _Em 530nm, the PL intensity increases.

Experimental Example 2: SEM measurement of the phosphor of Example 1

The size and shape of the phosphor of Example 1 were confirmed by obtaining SEM photographs of the glass-coated phosphor prepared in Example 1, in which the mixing ratio of glass frit and phosphor was 6: 4, using a known method.

Further, after the phosphor of Example 1 was exposed to moisture for 48 hours, SEM photographs were obtained again, and the results are shown in FIG.

Referring to FIG. 2, FIG. 2 (A) is a photograph of a phosphor SEM of Example 1 before immersion in water, and FIG. 2 (B) shows a SEM photograph of the phosphor of Example 1 after immersion in water.

Comparing FIG. 2 (A) and FIG. 2 (B), SEM photographs were not significantly different before and after water was added, but it was confirmed that the glass coated phosphor of small size was washed away after exposure to moisture there was.

Experimental Example 3: Improvement of moisture vulnerability of the phosphor of Example 1

In order to confirm whether the glass-coated phosphors prepared by different mixing ratios of glass frit and phosphor in Example 1 were improved in moisture susceptibility of the phosphor after substantially exposed to moisture, The PL intensity was measured by using a conventionally known method after maintaining each of the glass coated phosphors at 85 DEG C / 85% humidity for 48 hours, and the results are shown in FIG.

Referring to FIG. 3, it can be seen that as the ratio of the phosphor increases, the PL intensity (Before graph) after exposure to moisture is reduced from the PL intensity (Before graph) before exposure to moisture.

In addition, the PL intensity of the conventional fluorescent material (Ref.) Not coated with glass as a control was measured before exposure to water for 48 hours as described above, and compared with Example 1 of the present invention. The results are shown in FIG. 4 .

Referring to FIG. 4, the relative PL intensity is shown in a bar graph. In the case of the control group, the phosphor does not emit light after exposure to moisture, whereas in the case of Example 1, It is shown that the phosphors emit light both before and after the exposure. Particularly, the higher the mixing ratio of the phosphor, the smaller the reduction in the intensity of light emission than before exposure to moisture.

As a result, it was confirmed that the glass-coated phosphor according to the present invention was remarkably improved in moisture fragility.

EXPERIMENTAL EXAMPLE 4 Whether or not the moisture sensitivity of the phosphor of Example 2 improves

In order to confirm whether or not each glass-coated phosphor prepared by different mixing ratios of glass frit and phosphor in Example 2 was improved in moisture susceptibility of the phosphor after substantially exposed to moisture, the same method as Experimental Example 3 And the relative PL intensity was measured.

The results of the experiment are shown in FIG. FIG. 5 shows the relative PL intensity as a bar graph. When the mixing ratio of the glass frit and the phosphor is varied from 8: 2 to 3: 7, that is, the higher the mixing ratio of the phosphor is, And the reduction rate of the strength of the steel is reduced. However, when the mixing ratio of the glass frit and the phosphor was 2: 8, it was confirmed that the light emission intensity was somewhat reduced. Ref. 5 of FIG. 5 shows a relative PL intensity before exposure to moisture as a conventional phosphor coated with no glass.

Experimental Example 5: Effect of pelletizing process on improvement of moisture susceptibility

The glass-coated phosphor prepared by mixing the glass frit and the phosphor in the mixing ratio of the glass frit and the phosphor of Example 1 was mixed with the glass frit and the phosphor in the mixing ratio of 6: 4 in Example 1, (Control group) on the improvement of moisture susceptibility. The same method as described in Experimental Example 3 was used for the experiment for improving the water vulnerability.

The results of the experiment are shown in FIG. Referring to FIG. 6, when the graph of the pellet before test and the pellet after test of the sample of Example 1 were compared with each other, the decrease was observed before the control was exposed to moisture non-pellet before test) and non-pellet after test (wet).

Figure 7 also shows the relative PL intensity as a bar graph, and the difference between the pre-test and post-test bar graphs of the non-pellet samples was similar to that of the pellet samples before and after the test It is confirmed that the reduction of emission intensity is remarkably reduced even when the phosphor prepared after the pellet process of the present invention is exposed to moisture. Thus, it was confirmed that the pellet processing step plays a significant role in improving the moisture susceptibility. Ref. 7 shows the relative PL intensity before exposure to moisture as a conventional phosphor coated with no glass.

Experimental Example 4: Improvement of thermal vulnerability of the phosphor of Example 1

In order to confirm whether or not the glass-coated phosphor prepared by mixing the glass frit and the phosphor in the mixing ratio of the glass frit and the phosphor of Example 1 substantially improved the thermal vulnerability, the glass-coated phosphor was subjected to TQ (thermal quenching) measurements were performed. As a control, a conventional phosphor not coated with glass as a control group was also subjected to TQ measurement, and the results of the experiment are shown in FIG.

Referring to FIG. 8, it was confirmed that the glass-coated phosphor of the present invention exhibited a relatively high PL intensity at a temperature of 100 ° C. or higher as compared with the control. As a result, it was confirmed that the glass-coated phosphor according to the present invention had better thermal stability than the conventional phosphor.

Experimental Example 5 EL characteristics test of a white light emitting device including the phosphor of Example 1

In order to confirm whether the glass-coated phosphor prepared by mixing the glass frit and the fluorescent material in the ratio of 6: 4 in Example 1 can be used as a substantially white light-emitting device, the glass-coated fluorescent material of Example 1 And the EL characteristics were measured and analyzed. The results are shown in FIGS. 9 and 10. FIG.

9 and 10, it was confirmed that the phosphor of Example 1 of the present invention exhibited excellent optical characteristics under excitation of about 450 nm, and 20 mA was applied to the white LED manufactured by the phosphor of Example 1 (0.295, 0.333), respectively. These results show that the glass-coated phosphors according to the present invention can be used for white LEDs with improved efficiency.

Although several embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various modifications may be made without departing from the principles and spirit of the invention . The scope of the invention will be determined by the appended claims and their equivalents.

Claims (5)

In a method for producing a glass-coated phosphor,
Preparing a mixture of a glass frit and a phosphor;
Preparing pellets with the prepared mixture;
Subjecting the pellet to a heat treatment to produce a plate;
And grinding the plate to obtain a glass-coated phosphor. The method according to claim 1,
In the mixture preparation step,
Wherein the glass frit is mixed at 10 to 80 wt% and the phosphor is mixed at 20 to 90 wt% with respect to the whole mixture. 3. The method of claim 2,
Wherein the heat treatment is performed at 600 to 800 ° C for 1 to 12 hours. A glass-coated phosphor produced by the method of any one of claims 1 to 3. A white light emitting device comprising a glass-coated phosphor produced by the method of any one of claims 1 to 5.

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