WO2016114480A1 - Color conversion glass for leds having excellent light uniformity - Google Patents

Abstract

Disclosed is a color conversion glass for LEDs having excellent light uniformity. The color conversion glass for LEDs according to the present invention is a color conversion glass (phosphor in glass: PIG), disposed on the front of an LED, for converting colors, wherein a filler having a refractive index of 1.63-1.80 is added to a basic color conversion glass containing phosphor and glass having a refractive index of 1.5-1.6.

Description

Color conversion glass for LED with excellent light uniformity

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Phosphor In Glass (PIG) manufacturing technology, and more particularly, to a color conversion glass for LED having excellent color conversion efficiency and excellent light uniformity.

Phosphors are required for white light emission from LEDs emitting monochromatic light such as blue light.

The following three methods are mainly used to implement the phosphor.

The first method is to mold silicon mixed with yellow phosphor on a blue LED chip. In the case of the white LED package manufactured in such a form, there is a problem in that yellowing occurs due to deterioration of the color conversion material at a high temperature, and also serves as a main factor in the deterioration of reliability due to gas and moisture penetration.

The second is a method of dispersing and molding a yellow phosphor in an organic material such as epoxy. In this case, too, there is a problem that the heat resistance is weak by using an organic material.

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

On the other hand, in the case of such a color conversion glass, the light is concentrated in the center portion of the front surface of the LED light source, there is a problem that the light intensity is somewhat lower.

As a solution to this problem, a separate member such as a diffuser plate is mainly disposed on the front surface of the color conversion glass. However, in the case of such a method, the cost is greatly increased according to the use of a separate member such as a diffusion plate, and there is a problem in that the light intensity decreases while the light passes through the diffusion plate.

Background art related to the present invention is a LED lighting diffusion member disclosed in the Republic of Korea Patent Publication No. 10-2011-0054680 (published on May 25, 2011) and the LED lamp having the same. The document discloses a diffusion member having a cover and a diffusion plate, and having a structure in which irregularities are formed in the diffusion plate.

An object of the present invention is to provide a color conversion glass that can exhibit excellent light uniformity without using a separate member such as a diffusion plate.

Color conversion glass for LED according to an embodiment of the present invention for achieving the above object is a color conversion glass (Phosphor In Glass (PIG)) is disposed on the front surface of the LED to convert the color, phosphor and glass having a refractive index of 1.5 ~ 1.6 A filler having a refractive index of 1.63 to 1.80 is added to the basic color conversion glass to be included.

In this case, the filler may include at least one of sapphire single crystal powder and lanthanum glass powder.

In addition, the filler may be added to 50 parts by weight or less based on 100 parts by weight of glass.

Moreover, it is preferable that the said filler has a largest particle diameter of 20 micrometers or less.

In addition, the glass by weight, SiO ₂ 55-70%, Al ₂ O ₃ 10-22%, B ₂ O ₃ 1-15%, CaO 10% or less and SrO 2-10%, R ₂ O (R = Li, Na, K, Rb and Cs), Sb ₂ O ₃ , F, Cl, SO ₃ , P ₂ O ₅ , V ₂ O ₅ , PbO, ZnO and Bi ₂ O ₃ are not intentionally added May be glass.

In addition, the glass by weight, SiO ₂ 55-70%, Al ₂ O ₃ 10-22%, B ₂ O ₃ 1-15%, CaO 10% or less, SrO 2-10%, MgO 5% by weight or less And BaO: made of at least one of 5 wt% or less, R ₂ O (R = Li, Na, K, Rb and Cs), Sb ₂ O ₃ , F, Cl, SO ₃ , P ₂ O ₅ , V _It may be a glass in which ₂ O ₅ , PbO, ZnO and Bi ₂ O ₃ are not intentionally added.

The color conversion glass for LEDs according to the present invention has an advantage of exhibiting excellent light uniformity as a result of adding a filler having a refractive index of 1.63 to 1.80 to the basic color conversion glass.

1 schematically shows an example of an LED package to which the color conversion glass according to the present invention is applied.

2 shows an example in which light is concentrated near a direction angle of 90 °.

3 shows an example in which light is evenly distributed at a direction angle of 45 ° to 135 °.

[Description of the code]

101: package body 102: LED chip

103: color conversion glass

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments and drawings described below in detail. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, only the embodiments are to make the disclosure of the present invention complete, it is common in the art It is provided to fully inform those skilled in the art of the scope of the invention, which is to be defined only by the scope of the claims.

Hereinafter, with reference to the accompanying drawings, it will be described in detail with respect to LED color conversion glass excellent in the light uniformity according to the present invention.

1 schematically shows an example of an LED package to which the color conversion glass according to the present invention is applied.

Referring to FIG. 1, an LED chip 102 is mounted on a package body 101. As described above, the light emitted from the LED chip 102 is mainly a blue wavelength, and in order to use it as white light, a yellow phosphor having a complementary color relationship with blue is required or red and green phosphors for constituting three primary colors of light. Is required.

This phosphor is included in the color conversion glass 103 mounted on the front of the package.

FIG. 2 illustrates an example in which light is concentrated around a direction angle of 90 °, and FIG. 3 illustrates an example in which light is evenly distributed at a direction angle of 45 ° to 135 °. When using an LED as a light source such as a lighting lamp, a car lamp, a backlight unit, it is necessary to secure a light uniformity at a wide orientation angle as shown in FIG. 3.

Color converting glass (Phosphor In Glass (PIG)) according to the present invention is a color conversion glass for converting the color disposed on the front of the LED, and includes a phosphor and a glass having a refractive index of 1.5 ~ 1.6. The phosphor may be included in an amount of about 3 to 70 wt% based on the total weight of the phosphor and the glass. The content of the phosphor may be adjusted by the thickness of the color conversion glass, the LED size, the number of LEDs, and the like.

In addition, the color conversion glass according to the present invention is characterized in that a filler having a refractive index of 1.63 to 1.80 is added to the basic color conversion glass including such a phosphor and glass. As a result of the addition of a filler having a higher refractive index than that of glass, it was possible to exhibit excellent optical uniformity at a wide orientation angle, because the diffuse reflection was increased by the filler.

In this case, the filler may include at least one of sapphire single crystal powder and lanthanum glass powder.

Moreover, it is preferable that a filler is added in 50 weight part or less with respect to 100 weight part of glass contained in basic color conversion glass. As the filler content is increased, light uniformity may be improved by increasing diffuse reflection, but when the filler is excessively more than 50 parts by weight, the light transmittance may be greatly reduced. When comprehensively considering securing the light uniformity and preventing light transmittance, the filler is more preferably contained in an amount of 10 to 40 parts by weight, and most preferably in an amount of 15 to 30 parts by weight.

Moreover, it is preferable that a filler has a largest particle diameter of 20 micrometers or less. When the filler size is coarse beyond 20 µm, an excessively large roughness may be generated on the surface of the color conversion glass having a thickness of about 500 µm, thereby decreasing the light transmittance.

On the other hand, the glass included in the basic color conversion glass in weight%, SiO ₂ 55-70%, Al ₂ O ₃ 10-22%, B ₂ O ₃ 1-15%, CaO 10% or less and SrO 2-10% Consisting of R ₂ O (R = Li, Na, K, Rb and Cs), Sb ₂ O ₃ , F, Cl, SO ₃ , P ₂ O ₅ , V ₂ O ₅ , PbO, ZnO and Bi ₂ O ₃ may be glass that is not intentionally added. (Glass composition 1)

In addition, the glass contained in the basic color conversion glass in weight%, SiO ₂ 55-70%, Al ₂ O ₃ 10-22%, B ₂ O ₃ 1-15%, CaO 10% or less, SrO 2-10% , MgO 5% by weight or less, BaO: 5% by weight or less of one or more, and R ₂ O (R = Li, Na, K, Rb and Cs), Sb ₂ O ₃ , F, Cl, SO ₃ , It may be a glass in which P ₂ O ₅ , V ₂ O ₅ , PbO, ZnO and Bi ₂ O ₃ are not intentionally added. (Glass composition 2)

In the case of the glasses, components capable of exhibiting chemical reactions with phosphors, such as R ₂ O (R = Li, Na, K, Rb and Cs), Sb ₂ O ₃ , F, Cl, SO ₃ , By preventing the use of P ₂ O ₅ , V ₂ O ₅ , PbO, ZnO, and Bi ₂ O ₃ , the color conversion efficiency can be maximized and bubbles can be suppressed by firing for a short time above the softening temperature. As a result, light transmittance and light extraction efficiency can be improved.

Hereinafter, the role of each component and its content will be described.

SiO ₂ contributes to improving the glass stability by forming a three-dimensional network structure. The SiO ₂ is preferably added at 55 to 70% by weight of the total weight of the glass. When the addition amount of SiO ₂ is less than 55% by weight, the addition effect is insufficient. In contrast, if SiO ₂ exceeds 70% by weight, there is a problem in the glass softening temperature is too high.

Al ₂ O ₃ contributes to glass stabilization. The Al ₂ O ₃ is preferably added at 10 to 22% by weight of the total weight of the glass. When the addition amount of Al ₂ O ₃ is less than 10% by weight, the addition effect is insufficient. On the contrary, when the addition amount of Al ₂ O ₃ exceeds 22% by weight, the glass fluidity may be greatly reduced.

B ₂ O ₃ contributes to the formation of mesh, and contributes to lowering the firing temperature through viscosity reduction. The B ₂ O ₃ is preferably added in 1 to 15% by weight of the total weight of the glass. When the amount of B ₂ O ₃ added is less than 1% by weight, the effect of addition is insufficient. In contrast, when the amount of B ₂ O ₃ added exceeds 15% by weight, crystallization of the glass may proceed rapidly.

CaO and SrO lower the softening temperature of the glass, contributing to lowering the firing temperature for producing color converted glass. These components are preferably added in CaO: 10% by weight or less, SrO: 2-10% by weight, and may further include one or more of 5% by weight or less of MgO and 5% by weight or less of BaO. In addition, the total content of CaO, SrO, MgO, BaO is more preferably 10 to 25% by weight of the total weight of the glass. In the above range, the softening temperature may be lowered without reducing the light transmittance, and when any component exceeds the above range, problems such as reduced fluidity and promotion of crystallization may occur.

The glass having the composition may be prepared by firing at about 800 ° C. or more corresponding to a softening temperature or more. When firing below the softening temperature of the glass powder, there is a problem that a large amount of bubbles are generated in the fired glass to lower the light transmittance and light extraction efficiency, it is preferable to perform the firing above the softening temperature of the glass powder. However, when the firing temperature is too high exceeding 980 ℃, phosphor discoloration may occur.

In order to evaluate the effect of the glass composition was carried out the following experiment.

To the glass powder having a glass composition shown in Table 1 and Table 2, the phosphors were mixed in the same amount and molded in a plate form, and then baked at the firing temperature shown in Table 3 for 30 minutes to prepare a color conversion material.

In Table 1 and Table 2, a unit is a weight part, and when a total is 100 weight part, it is the same value as weight%.

TABLE 1

TABLE 2

TABLE 3

(2) Visually evaluating the phosphor reaction with respect to the basic color conversion glass to which glass compositions 1 to 42 were applied, and evaluated according to the following criteria.

O: Excellent (no phosphor discoloration)

(Triangle | delta): Normal (phosphor discolors finely)

X: Not applicable (phosphor discoloration)

Referring to Table 3, in the case of the specimens 38 to 41 satisfying the glass component presented in the present invention, the phosphor discoloration did not occur as a whole, although firing was performed at 800 ° C. or higher. However, in case of specimen 42, the phosphor was slightly discolored when firing was performed at an excessively high temperature of 1000 ° C.

However, in the case of specimens 1 to 37 that did not satisfy the glass component presented in the present invention, phosphor discoloration occurred as a whole.

Table 4 shows the intensity of light for each of the beam angles for the two color conversion glasses. When the intensity of light at the 90 ° directivity angle corresponding to the front surface of the LED light source was 100%, the intensity was expressed as a relative value at another directivity angle.

As a comparative example, a filler was not added to the basic color conversion glass composed of the glass having the glass composition of No. 38 and the phosphor of Table 2, and the refractive index was 1.76 and the maximum particle diameter of the basic color conversion glass having the glass composition of No. 38 of Table 2 was used. An example was given when 20 parts by weight of sapphire single crystal powder filler having a thickness of 20 μm was added to the glass weight contained in the basic color conversion glass.

TABLE 4

Referring to Table 4, it can be seen that in the case of the embodiment in which the filler is added in an appropriate amount, the light uniformity is relatively excellent in the remarkably wide direction angle range compared to the comparative example in which the filler is not added.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above embodiments and can be modified in various forms, and having ordinary skill in the art to which the present invention pertains. It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Claims (6)

Phosphor In Glass (PIG) disposed on the front of the LED to convert color, The color conversion glass characterized by adding the filler of refractive index 1.63-1.80 to the basic color conversion glass containing fluorescent substance and the glass of refractive index 1.5-1.6. The method of claim 1, The filler is a color conversion glass, characterized in that it comprises at least one of sapphire single crystal powder and lanthanum-based glass powder. The method of claim 1, The filler is added to 50 parts by weight or less based on 100 parts by weight of glass, color conversion glass. The method of claim 1, The filler has a maximum particle diameter of 20㎛ or less, color conversion glass. The method of claim 1, The glass is By weight%, consisting of 55 to 70% SiO ₂ , 10 to 22% Al ₂ O ₃ , 1 to 15% B ₂ O ₃ , CaO 10% or less and SrO 2 to 10%, R ₂ O (R = Li, Na, K, Rb and Cs), Sb ₂ O ₃ , F, Cl, SO ₃ , P ₂ O ₅ , V ₂ O ₅ , PbO, ZnO and Bi ₂ O ₃ are intentionally Color converting glass, characterized in that the glass is not added. The method of claim 1, The glass is By weight%, SiO ₂ 55-70%, Al ₂ O ₃ 10-22%, B ₂ O ₃ 1-15%, CaO 10% or less, SrO 2-10%, MgO 5% by weight or BaO: 5 weight It consists of one or more of% or less, R ₂ O (R = Li, Na, K, Rb and Cs), Sb ₂ O ₃ , F, Cl, SO ₃ , P ₂ O ₅ , V ₂ O ₅ , PbO, ZnO and Bi ₂ O ₃ are intentionally Color converting glass, characterized in that the glass is not added.

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