KR20170000419A - Manufacturing method of poreless structure phosphor in glass for light emitting diode - Google Patents

Abstract

The present invention relates to a manufacturing method of poreless structure phosphor in glass for a light emitting diode which can improve transmissivity and optical extraction while reducing crack defects. The manufacturing method of the poreless structure phosphor in glass comprises the following steps: (a) molding glass slurry to which phosphor is added, and drying the same to form a glass molded body; (b) pre-plasticizing the glass molded body primarily at a temperature under the softening point; and (c) plasticizing the glass molded body secondarily in a vacuum condition at a temperature between the softening point and 20C above the softening point.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a color conversion glass for a LED,

The present invention relates to a method of manufacturing a color conversion glass for LED, and more particularly, to a method of manufacturing a color conversion glass for LED having a forelain structure capable of improving transmittance and light extraction efficiency while minimizing cracking due to post- .

A phosphor is required for emitting white light from an LED (light emitting diode) emitting monochromatic light such as blue light.

As the method of implementing the phosphor, the following three main methods are used.

Firstly, it is a method of molding silicon mixed with a yellow phosphor on a blue LED chip. In the case of a white LED package manufactured in this form, yellowing occurs due to deterioration of a color conversion material at a high temperature, and further, reliability is deteriorated due to gas and moisture permeation.

Secondly, the yellow phosphor is dispersed and molded in an organic material such as epoxy or the like. In this case, too, there is a problem that the heat resistance is weak due to the use of the organic material.

Third, it is a method of mounting a color conversion glass (Phosphor In Glass; PIG) in which yellow phosphor is dispersed in glass in a cover form. In this case, the problem of high temperature deterioration as described above can be solved, and resistance to gas and moisture penetration is also excellent.

In the case of such a color conversion glass, there is a problem that light is concentrated in the central part of the front face of the LED light source and the light intensity is somewhat low in the other part.

In order to solve this problem, a separate member such as a diffusing plate is disposed in front of the color conversion glass.

However, in the method of disposing the diffusing plate on the entire surface of the color converting glass, there is a problem in that the cost is greatly increased by the use of the separate member such as the diffusing plate, and the light intensity is reduced while the light passes through the diffusing plate.

In addition, the conventional color conversion glass causes cracks in processing after firing due to the distribution of a large amount of clogged pores in the inside due to the melting of the edge portions having many pores at the time of firing at a temperature above the softening point, There was a problem.

A related prior art is Korean Patent Laid-Open Publication No. 10-2015-0048948 (published on May 5, 2015), which discloses a glass composition for supporting a phosphor, a ceramic color conversion member containing the same, and a white light emitting diode .

It is an object of the present invention to provide a method of manufacturing a color conversion glass for LED having a forelain structure capable of improving the transmittance and the light extraction efficiency while minimizing cracks caused by post-processing.

According to another aspect of the present invention, there is provided a method of manufacturing a color conversion glass for LED having a pore structure, the method comprising the steps of: (a) forming and processing a glass slurry to which a phosphor is added, followed by drying to form a glass molded body; (b) prefiring the glass molded body primarily at a temperature lower than the softening point; And (c) firing the pre-fired glass formed body in a vacuum state at a temperature ranging from a softening point to a softening point + 20 ° C.

In the method for manufacturing a color conversion glass for a LED having a pore structure according to the present invention, prefiring is performed at a temperature lower than the softening point, so that only 1 to 5% of the glass molded article is shrunk to form an open pore channel, The pre-fired glass formed body is subjected to vacuum firing while keeping the temperature near the softening point or gradually raising the temperature at a heating rate of 1 DEG C / min or less to obtain a uniform temperature profile The pores can be completely removed by controlling the rapid shrinkage in the edge region of the glass shaped article to prevent the formation of closed pores at this portion.

Accordingly, the method for manufacturing a color conversion glass for LEDs having a pore structure according to the present invention has a pore-free pore structure, thereby minimizing cracks due to post-processing, and maximizing the transmittance and light extraction efficiency.

FIG. 1 is a process flow diagram showing a method for manufacturing a color conversion glass for a LED having a forelith structure according to an embodiment of the present invention.
2 is a schematic process diagram for explaining the vacuum firing process.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish them, will become apparent by reference to the embodiments described in detail below with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Hereinafter, a method of manufacturing a colorless glass for LED according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a process flow diagram showing a method for manufacturing a color conversion glass for a LED having a forelith structure according to an embodiment of the present invention.

Referring to FIG. 1, a method of manufacturing a colorless glass for LED according to an embodiment of the present invention includes a glass molding forming step (S110), a preliminary firing step (S120), and a vacuum firing step (S130).

Glass molding

In the glass forming body forming step (S110), the glass slurry to which the phosphor is added is molded and processed, followed by drying to form a glass molded body.

In this step, the glass slurry includes a glass frit, a phosphor, a binder resin and a solvent.

At this time, the glass frit serves as a base material for forming a glass green sheet. This glass frit is one example, SiO _2, Al ₂ O _3, alkaline earth metal oxides (MgO, CrO, SrO, BaO), and B ₂ O ₃ may include a main component of the alkali-free alumino-borosilicate glass components, but this But is not limited to. That is, the glass frit may be used by mixing two or more kinds of glass frit having different melting points. In this case, it is appropriate to use glass frit having a large melting point difference between two or more kinds of glass frit.

The binder resin is added for the purpose of providing a bonding force between glass frit. As such a binder resin, known binder resins such as PVB (polyvinylbutyral), PVA (polyvinyl alcohol), acrylic, and cellulose may be used.

The solvent serves to control the viscosity of the glass paste, and alcoholic solvents, ketonic solvents, etc. may be used alone or in combination of two or more.

As the phosphor, various known phosphors can be used. Typical examples of the phosphor include a YAG, LuAg, TAG, silicate, SiAlON, BOS, and oxy nitride phosphides.

At this time, the molding can be performed by any one of press molding, injection molding and tape casting molding, and it is more preferable to use the tape casting molding method.

Thus, the glass slurry to which the phosphor is added is molded and processed, and then dried to form a glass molded body. Accordingly, the glass formed body is in a green sheet state.

Preliminary firing

In the preliminary firing step (S120), the glass preform is primarily prefired at a temperature lower than the softening point. By performing this preliminary firing, only 1 to 5% of the glass molded body is contracted, and an open pore channel is formed to the inside.

At this time, the softening point of the glass molded article is slightly different depending on the content of the glass frit, but the temperature at which the viscosity becomes 10 ^7.6 poise or less can be defined as the softening point or more.

Therefore, prefiring in the present invention is preferably performed at 500 to 750 ° C. If the pre-firing temperature is less than 500 ° C, the shrinkage of the glass formed body may not satisfy the target value. On the contrary, when the prebaking temperature exceeds 750 DEG C, there is a great possibility that the pore channel opened due to excessive shrinkage collapses.

Vacuum plasticity

In the vacuum firing step (S130), the pre-fired glass formed body is secondarily fired at a temperature from the softening point to the softening point + 20 占 폚 in a vacuum state.

At this time, the softening point of the glass molded article is slightly different depending on the content of the glass frit, but the temperature at which the viscosity becomes 10 ^7.6 poise or less can be defined as a softening point or more, specifically 600 to 850 ° C.

2 is a schematic process diagram for explaining the vacuum firing process.

As shown in Fig. 2, the pre-fired glass formed body G is subjected to vacuum firing by means of the vacuum heating apparatus 1. Fig. At this time, the prefired glass formed body (G) is mounted on a vacuum chuck (20) mounted inside a vacuum chamber (10) kept in a vacuum state. This glass formed body G is transferred to the inside of the vacuum chamber 10 through the gate valve 15 and is placed on the vacuum chuck 10.

Inside the vacuum chuck 10, a heater 40 for heating the glass formed body G to a baking temperature is mounted. The heater 40 may be designed to be divided into a plurality of portions so as to allow local heating, but the present invention is not limited thereto.

An elevating unit 30 having a lift pin 35 for controlling the height of the glass formed body G is mounted on the lower portion of the vacuum chuck 20. [ A vacuum pump 50 for adjusting the degree of vacuum in the vacuum chamber 10 is installed at a lower end of the vacuum chamber 10.

As described above, in the present invention, since the preliminarily fired glass formed body (G) is heated at a temperature rising rate of 1 ° C / min or less while maintaining the temperature at a softening point to a softening point + 20 ° C, By forming a uniform temperature profile in the entire area of the molded product G, the formation of closed pores can be prevented by controlling the rapid shrinkage in the edge region of the glass molded product G, so that the pores can be completely removed.

Alternatively, in the present invention, glass frit mixed with two or more different melting points may be used. In particular, it is appropriate to use glass frit having a large melting point difference between two or more kinds of glass frit. If vacuum firing is performed using glass frit having two or more different melting points, melting points of the glass frit are different from each other, thereby preventing the glass frit from sharply contracting.

Alternatively, in the present invention, the sintering temperature profile is maintained at around the sintering initiation temperature during the vacuum sintering process, and then the sintering temperature is raised at a rate of 1 ° C / min or less so that the sintering is slowly performed, Thereby completely removing the pores.

In this step, when the firing temperature is lower than the softening point, a large amount of bubbles are generated in the fired glass frit, thereby lowering the light transmittance and the light extraction efficiency. On the other hand, if the baking temperature is too high, exceeding the softening point + 20 ° C, discoloration may occur in the phosphor.

In addition, the firing is performed in the order of heating, holding and cooling. At this time, the firing holding time is preferably 10 to 120 minutes. If the firing holding time is less than 10 minutes, there is a high possibility that firing will not be sufficient. On the other hand, when the firing holding time exceeds 120 minutes, there is a problem that the phosphor characteristics are lowered due to the reaction between the phosphor and the glass frit.

In the method of manufacturing a color conversion glass for LED of the forelithic structure according to the above-described embodiment of the present invention, pre-firing is performed at a temperature lower than the softening point so that only 1 to 5% of the glass molded body is shrunk, (open pore channel) is formed, and then the pre-fired glass formed body is allowed to stand in the vicinity of the softening point By maintaining the temperature or slowly raising the temperature to less than 1 DEG C / min, the vacuum firing proceeds to produce a uniform temperature profile in the entire region of the glass compact, thereby controlling rapid shrinkage in the edge region of the glass compact, The pores can be completely removed.

Accordingly, the method for manufacturing a color conversion glass for LED of the pore-less structure according to an embodiment of the present invention has a pore-free structure having no pores, thereby minimizing cracks due to post-processing and maximizing the transmittance and light extraction efficiency .

Example

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

1. Color conversion glass manufacturing

Example 1

A glass slurry in which the phosphors were added in the same amounts to the glass frit described in Table 1 was molded and processed, and then dried at 50 DEG C to form a glass molded body.

Next, the glass molded body was pre-baked at 620 占 폚 for 30 minutes, and vacuum-baked at a temperature of 830 占 폚 in a vacuum chamber maintained at 3 Torr for 80 minutes to prepare a color conversion glass.

Example 2

A glass slurry in which the phosphors were added in the same amounts to the glass frit described in Table 1 was molded and processed, and then dried at 50 DEG C to form a glass molded body.

Next, the glass molded body was prebaked at 680 占 폚 for 30 minutes, and then vacuum fired at a temperature of 820 占 폚 in a vacuum chamber maintained at 4 Torr for 80 minutes to prepare a color conversion glass.

Example 3

A glass slurry in which the phosphors were added in the same amounts to the glass frit described in Table 1 was molded and processed, and then dried at 50 DEG C to form a glass molded body.

Next, the glass molded body was prebaked at 650 캜 for 40 minutes, and vacuum fired at a temperature of 830 캜 for 110 minutes in a vacuum chamber maintained at 6 Torr to produce a color conversion glass.

Example 4

A glass slurry in which the phosphors were added in the same amounts to the glass frit described in Table 1 was molded and processed, and then dried at 45 DEG C to form a glass molded body.

Next, the glass molded body was prebaked at 710 占 폚 for 50 minutes, and then vacuum fired at a temperature of 810 占 폚 for 100 minutes in a vacuum chamber maintained at 7 Torr to prepare a color conversion glass.

Comparative Example 1

A glass slurry in which the phosphors were added in the same amounts to the glass frit described in Table 1 was molded and processed, and then dried at 45 DEG C to form a glass molded body.

Next, the glass molded body was pre-baked at 760 캜 for 20 minutes, and vacuum fired at a temperature of 830 캜 for 90 minutes in a vacuum chamber maintained at 4 Torr to prepare a color conversion glass.

[Table 1] (unit:% by weight)

2. Property evaluation

Table 2 shows the physical property evaluation results of the color conversion glasses according to Examples 1 to 4 and Comparative Example 1.

1) Measurement of transmittance

The light transmittance of 400 nm to 800 nm wavelength was measured by ultraviolet / visible light spectrum measurement (UV-vis meter, cary).

[Table 2]

Referring to Table 1 and Table 2, it can be seen that the color conversion glass according to Examples 1 to 4 satisfies all of the transmittances of 95% or more, which is considered to be due to the complete removal of pores .

On the other hand, in the case of the color conversion glass according to Comparative Example 1, it can be seen that the transmittance was measured to be 85.7%, which is lower than the target value. This is because the pre-firing temperature deviates from the temperature range suggested by the present invention, It is understood that the permeability is lowered due to the collapse of the channel and generation of closed pores.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. These changes and modifications may be made without departing from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims.

S110: Glass forming body forming step
S120: preliminary firing step
S130: Vacuum firing step

Claims (6)

(a) forming and processing a glass slurry to which a phosphor is added, followed by drying to form a glass molded body;
(b) prefiring the glass molded body primarily at a temperature lower than the softening point; And
(c) secondarily firing the pre-fired glass formed body in a vacuum state at a temperature ranging from a softening point to a softening point + 20 占 폚.
The method according to claim 1,
In the step (a)
The glass formed article
Wherein the green sheet is in a green sheet state.
The method according to claim 1,
The glass slurry
A glass frit, a phosphor, a binder resin and a solvent,
Wherein the glass frit is a mixture of two or more different melting points.
The method according to claim 1,
In the step (b)
The pre-
Wherein the heat treatment is carried out at 500 to 750 占 폚.
The method according to claim 1,
In the step (b)
Wherein an open pore channel is formed inside the glass molded body so that only the glass molded body is shrunk by 1 to 5% by the preliminary firing.
The method according to claim 1,
In the step (c)
The softening point
Wherein the glass transition temperature is in a range of 600 to 850 占 폚.

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