KR100626272B1 - Barium silicate phosphor, manufacturing method of the same, and white light emitting device and emitting film using the same - Google Patents

Abstract

The present invention discloses a yellow phosphor and a white light emitting device using the same. The phosphor of the present invention is a barium silicate system represented by (Ba _{1 - y} M _y ) _{3- x} SiO ₅ : Eu ^{2 +} _x (0 <x ≤ 1, 0 ≤ y ≤ 0.9, M = Sr, Ca, Mg) Phosphor. The light emitting device using the phosphor of the present invention has a broad wavelength spectrum, shows excellent properties in terms of color purity, and shows very high light emission efficiency when applied to a light emitting diode.

White Light Emitting Diode, Yellow, Phosphor, Barium Silicate

Description

Barium silicate-based phosphor, a method of manufacturing the same, and a white light emitting device and a light emitting film using the same TECHNICAL FIELD

1 is an XRD pattern of a barium silicate-based phosphor according to the present invention.

2 is a photoluminescence measurement result of the barium silicate-based phosphor according to the present invention.

3 is a schematic diagram of a light emitting device using a conventional phosphor.

4 is an emission spectrum of a white light emitting device using a barium silicate-based phosphor and a blue light emitting diode according to the present invention.

5 is an emission spectrum of a white light emitting device using a barium silicate-based phosphor and a long wavelength ultraviolet light emitting diode according to the present invention.

The present invention relates to a phosphor and a white light emitting device using the same, and more particularly to a barium silicate-based phosphor, a method for manufacturing the same and a white light emitting device using the same.

White LEDs are one of the next generation light emitting devices that can replace conventional general lighting. The white light emitting diode has much lower power consumption than a conventional light source, exhibits high light emission efficiency and high brightness, and has a long life and a fast response speed. There are three methods for manufacturing a white light emitting diode.

The first method uses a mixture of high-brightness red, green, and blue light emitting diodes, and has a disadvantage in that the circuit is complicated and expensive because three light emitting devices must be manufactured using three chips.

The second method is to coat red, green and blue light emitting phosphors on a long wavelength ultraviolet light emitting diode, which is disclosed in international patent application WO9839805. This method is the most ideal way to generate three wavelength white light by transmitting ultraviolet light through three primary fluorescent materials. However, since the heat is emitted from the light emitting diodes badly, the light emitting efficiency is not good. In addition, no phosphor having good luminous efficiency with respect to long-wavelength ultraviolet rays is found, and thus, in the conventional case, only 2 to 3 mW of output is shown. Organic resins are used as resins to cover ultraviolet rays, and organic resins absorb and deteriorate ultraviolet rays, thereby degrading the life and quality of LEDs.

The third method is to manufacture a white light emitting diode coated with a yellow light emitting phosphor on a blue light emitting diode, which is currently the most widely studied. This has the advantage that the structure is simple and easy to manufacture and obtain high brightness white light. This method is described in detail in International Application Publication No. WO9805078 filed by Nichia, Japan, and published by S. Nakamura (S. Nakamura, "The Blue Laser Diode", Springer-Verlag, P. 216-219, 1997). It is also described in detail. This is a blue light emitted from the light emitting diode yttrium aluminum garnet _{(Y 2 Al 5 O 12:} Ce 3 +; YAG) and to emit light of yellow and then absorbed in the phosphor of, a combination of blue and yellow light White light is produced. However, such a YAG-based light emitting phosphor has a relatively weak light emission intensity in the red region due to the nature of the light emission wavelength, which makes it difficult to obtain excellent color rendering characteristics and is sensitive to color temperature, which is not suitable for lighting and LCD color background light sources. there is a problem.

In order to solve these problems, new yellow light emitting phosphors other than YAG are urgently needed.

The present invention has been made to solve the problems of the prior art as described above, and to provide a phosphor that provides excellent light emission characteristics of high brightness.

Another object of the present invention is to provide a white light emitting device having excellent luminance of high brightness.

One aspect of the present invention for achieving the above object provides a barium silicate-based phosphor. This phosphor is a phosphor of the composition (Ba _{1 - y} M _y ) _{3- x} SiO ₅ : Eu ^{2 +} _x , wherein x is 0 <x ≤ 1, 0 ≤ y ≤ 0.9 and M is Sr, Ca and Mg It is configured to include one selected from a configured group.

When M is Sr, it is preferable that y is 0 ≦ y ≦ 0.9 in the composition formula. When M is Ca and Mg, it is preferable that y is 0 ≦ y ≦ 0.5 in the composition formula.

The present invention provides a method for producing a barium silicate-based phosphor. The phosphor is prepared by firing a mixture of a material containing barium carbonate (BaCO ₃ ), silica (SiO ₂ ), europium oxide (Eu ₂ O ₃ ), and at least one alkaline earth metal (M) (Ba _{1). -y} M _y ) A phosphor of _3-x SiO ₅ : Eu ²⁺ _x composition is prepared.

Another aspect of the present invention provides a white light emitting device. The white light emitting device is made of at least one light emitting diode emitting light in the region of 400 to 470 nm and the barium silicate-based phosphor. The phosphor consists of a formula of (Ba _{1 - y} M _y ) _{3- x} SiO ₅ : Eu ^{2 +} _x , wherein 0 <x ≤ 1, 0 ≤ y ≤ 0.9, and M is Sr, Ca, and Mg. It is configured to include one selected from a configured group.

The light emitting diode is a blue light emitting diode having a main peak wavelength of 460 nm, for example, InGaN, and the light excited by the phosphor may have a wavelength band of 500 to 700 nm. As another example, the light emitting diode is a long wavelength infrared light emitting diode having a main peak wavelength of 405 nm, for example, GaN, and the light excited by the phosphor may have a wavelength band of 450 to 700 nm.

Another aspect of the present invention provides a light emitting film. The light emitting film is represented by the chemical formula of (Ba _{1 - y} M _y ) _3-x SiO ₅ : Eu ²⁺ _x (0 <x ≤ 1, 0 ≤ y ≤ 0.9, and M is at least one of Sr, Ca, and Mg). And a barium silicate-based phosphor.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. However, the spirit of the present invention is not limited to the present embodiment, and other embodiments may be easily proposed by adding or replacing components.

A barium silicate-based phosphor according to an aspect of the present invention will be described. The production method will be described with reference to preferred embodiments.

First, barium silicate (BaCO ₃ ), silica (SiO ₂ ) and europium oxide (Eu ₂ O ₃ ) are mixed in a predetermined solvent. Specifically, the material is weighed in the desired proportions according to the desired composition, and the solvent uses ethanol for effective mixing. In addition, using a mixer such as ball milling (agate mortar) or agate mortar in the ethanol to mix and dry to a uniform composition. The drying temperature is 80 to 150 ° C, preferably 120 ° C, and the drying time is 1 to 24 hours, preferably 24 hours. The dried mixture is placed in a high purity alumina tube, the alumina tube is placed in an electric furnace, and heat treated in a reducing atmosphere. Here, when the heat treatment temperature is less than 800 ° C, single crystals of barium silicate are not completely produced, and thus the luminous efficiency is reduced. When the heat treatment temperature is higher than 1600 ° C, the luminance rapidly decreases due to overreaction. Therefore, the heat treatment temperature is preferably 800 to 1600 ° C, more preferably 1350 ° C. The heat treatment time is 1 to 48 hours, preferably 36 hours. Here, in order to create a reducing atmosphere, a hydrogen mixed gas of 2 to 25% can be used.

In addition, the heat treatment is carried out by adding a fluoride flux, the amount of the fluoride flux used is 0.1 to 5 wt% based on (Ba _{1 - y} M _y ) _{3- x} SiO ₅ : Eu ^{2 +} _x , preferably 2.5 wt%. Fluoride used in the present invention is barium fluoride, ammonium fluoride, sodium fluoride and the like. By heat treatment using such a fluoride, it is possible to easily obtain a single phase phosphor, and to obtain an excellent phosphor of high brightness even at a low synthesis temperature.

After the heat treatment, the mixture was cooled to room temperature and sufficiently pulverized to obtain a phosphor of a powder having a diameter of 5 to 20 μm.

Phosphor of the present invention forms a matrix is Ba and Si, and Eu ^{2 +} acts as a surfactant. If the amount of Eu is less than 0.001, it is not sufficient to serve as an activator. If the amount of Eu is more than 1, the luminance decrease due to concentration quenching effect is large, which is not preferable.

Figure 1 is the chemical formula Ba _{2 .94} SiO _5: shows the XRD diffraction pattern of a barium silicate-based phosphor Eu ^{2 +} _{0. 06.} Referring to FIG. 1, it is confirmed that the single phase of barium silicate is well formed.

2 is a result of measuring the photoluminescence (PL) of the barium silicate-based phosphor according to the present invention. Referring to FIG. 2, the emission intensity of the red region is higher than that of the conventional YAG system. Meanwhile, in the barium silicate-based phosphor, alkaline earth metal (M) may be substituted and added to the place of Ba ions. The result is _{(Ba 1 - y M y)} 2.97 SiO 5: Eu may be represented by the ^{2 +} _{0. 03. (Ba 1 - y M y)} 2.97 SiO 5: substituted with the amount of Eu ^{2 +} so as to addition of the alkaline earth metal ion in place of Ba ions at _0.03, of the Ba 1 mol of substance of 0.2 moles to 0.8 containing an alkaline earth metal molar do. Thereafter, the same process as the manufacturing method may be performed. 2 is the case where M is Sr. As the amount of strontium substituted is increased, the emission intensity in the red spectral region is increased. The alkaline earth metal (M) may be Sr, Ca, Mg, and the like, and in the case of Sr, the material containing the alkaline earth metal may be strontium carbonate.

A white light emitting device according to another aspect of the present invention will be described.

3 is a schematic diagram of a light emitting device using a conventional phosphor. Referring to FIG. 4, the white light emitting device includes a reflection cup 101, a light emitting diode 103 disposed on the reflection cup 101, and a phosphor excited by light emitted from the light emitting diode 103. 107, an electrode line 105 connected to the light emitting diode 103, and a light transmissive epoxy 109 encapsulating the light emitting diode chip 103. The light emitting diodes 103 are connected to an external power source by the pole line 105. The phosphor 107 is mixed with the epoxy resin 109 and disposed outside the light emitting diode 103. The phosphor 107 may be mixed with various resins such as silicone resins in addition to epoxy resins to form a white light emitting device in a manner of molding the light emitting diodes 103 around them. The phosphor 107 is formed outside the light emitting diode 103 so that light emitted from the light emitting layer of the light emitting diode 103 serves as excitation light of the phosphor 107.

4 is an emission spectrum of a white light emitting device using a barium silicate-based phosphor and a blue light emitting diode according to the present invention. The blue light emitting diode may be InGaN and generates blue light having a wavelength having a main peak of 460 nm. The phosphor of Ba ₂ SiO _{5 .97} made according to the present invention: and barium silicate-based phosphor having a composition ratio of Eu ^{2 +} _0.03, the phosphor of YAG series _{((Y 0 .9 Ce 0 .1} ) 3 Al 5 O 12 ) Was used as a comparative example.

When the white light is described in detail, the blue light emitted from the light emitting diode 103 (460 nm) passes through the barium silicate phosphor. Here, some light is used to excite a yellow phosphor made of barium silicate to implement yellow, and the other light is transmitted as it is as blue light. Therefore, as described above, the yellow light passing through the yellow phosphor and the blue light passing through the yellow phosphor as it is overlapped with each other to realize white light.

Referring to FIG. 4, the conventional YAG phosphor lacks the emission intensity of the red region and thus the color rendering characteristics are not good, whereas the barium silicate-based phosphor of the present invention exhibits excellent emission intensity in the red region. It can be seen that the wavelength of light excited by the barium silicate-based phosphor according to the present invention shows a broad wavelength spectrum of 500 to 700 nm, and the luminance is further improved as compared with the comparative example. Therefore, the barium silicate-based phosphor according to the present invention can be improved in color purity, and can be applied as a high-efficiency fluorescent material in a white light emitting device and an active light emitting liquid crystal display.

5 is an emission spectrum of a white light emitting device using a barium silicate-based phosphor and a long wavelength ultraviolet light emitting diode according to the present invention. The light emitting diode may be GaN and generates light having a wavelength having a main peak of 405 nm. The phosphor is a barium silicate phosphor having a composition ratio of Ba _2.97 SiO ₅ : Eu ²⁺ _0.03 prepared according to the present invention, and a YAG phosphor ((Y _0.9 Ce _0.1 ) ₃ Al ₅ O ₁₂ ) was used as a comparative example. .

Referring to FIG. 5, the phosphor of the present invention shows a broad spectrum of wavelengths at 450 to 700 nm in a long wavelength ultraviolet light emitting diode, and it is possible to confirm improved luminance than the phosphor of the comparative example. Although not shown, when a long wavelength ultraviolet light emitting diode of GaNrP or ZnOrP is used, a light emission peak of a green region, which does not appear in the blue light emitting diode, is displayed, thereby obtaining more improved color coordinates and luminance.

A light emitting film according to another aspect of the present invention will be described. A phosphor is barium silicate-based phosphor of the present invention _{(Ba 1 - y Sr y)} 2.97 SiO 5: Eu ^{2 +} was _{0. 03.}

(Example 1)

The barium silicate-based fluorescent material _{(Ba 1 - y Sr y)} 2.97 SiO 5: Eu 2 + 0. 03 with a polyester resin to f0.2: 0.8, 0.25: 0.75, 0.3: in a weight ratio of 0.7, the control tree illustration mill Mix while milling for 1 hour. The mixed batch was extruded with a screw extruder to prepare a master batch. The prepared master batch and the polyester resin were mixed in a weight ratio of 1: 1. This finally prepared master batch contains phosphors at 10%, 12.5% and 15.0%, respectively. This was put into a screw (for film production) extruder and melt-extruded at 260 ° C. to prepare a film having a thickness of 300 μm.

(Example 2)

The barium silicate-based phosphor and the polyimide resin were mixed at a weight ratio of 0.2: 0.8, 0.25: 0.75, and 0.3: 0.7 while milling with an attrition mill for 1 hour. The mixed batch was extruded with a screw extruder to prepare a master batch. The prepared master batch and polyimide resin were mixed in a weight ratio of 1: 1. This finally prepared master batch contains phosphors at 10%, 12.5% and 15.0%, respectively. This was put into a screw (for film production) extruder and melt-extruded at 260 ° C. to prepare a film having a thickness of 300 μm.

(Example 3)

The barium silicate-based phosphor and the polyvinyl chloride resin were mixed at a weight ratio of 0.2: 0.8, 0.25: 0.75, and 0.3: 0.7 while milling with an attrition mill for 1 hour. The mixed batch was extruded with a screw extruder to prepare a master batch. The prepared master batch and polyvinyl chloride resin was mixed in a weight ratio of 1: 1. This finally prepared master batch contains phosphors at 10%, 12.5% and 15.0%, respectively. This was put into a screw (film manufacturing) extruder and melt-extruded at 150 ° C. to prepare a film having a thickness of 300 μm.

(Example 4)

The barium silicate-based phosphor and General Purpose Polystyrene (GPPS) resin were mixed at a weight ratio of 0.2: 0.8, 0.25: 0.75, and 0.3: 0.7 while milling with an attrition mill for 1 hour. The mixed batch was extruded with a screw extruder to prepare a master batch. The prepared master batch and GPPS resin were mixed in a weight ratio of 1: 1. This finally prepared master batch contains phosphors at 10%, 12.5% and 15.0%, respectively. This was put into a screw (for film production) extruder and melt-extruded at 230 ° C. to prepare a film having a thickness of 300 μm.

The light emitting film thus prepared was attached to a light emitting device using a blue light emitting diode, and the color coordinates of Table 1 were analyzed using an integrating sphere. It can be seen that all exhibit excellent color coordinate characteristics.

content 10% 12.5% 15% location X Y X Y X Y Example 1 0.290 0.302 0.299 0.310 0.298 0.313 Example 2 0.285 0.302 0.294 0.308 0.300 0.312 Example 3 0.292 0.305 0.301 0.316 0.310 0.308 Example 4 0.287 0.289 0.292 0.302 0.303 0.298

As described in detail above, according to the present invention, a barium silicate-based yellow phosphor could be manufactured, and a phosphor having a broad spectrum of emission spectrum and emitting light efficiently even when a blue light emitting diode was used as an excitation energy source could be obtained. . Further, a barium silicate-based white light emitting device having a high emission intensity in the red region and excellent color rendering characteristics can be obtained.

In addition, even when the phosphor of the present invention is applied to a long wavelength ultraviolet light emitting diode, high luminance emission was confirmed and white was realized.

In addition, it was possible to efficiently increase the emission wavelength shift and emission through the Sr substitution of Ba site.

The phosphor of the present invention has a very high luminous efficiency when applied to a long wavelength ultraviolet light emitting diode and an active light emitting liquid crystal display, and thus is particularly effective when used as a back light source for a liquid crystal display such as lighting, a notebook, a mobile phone, and the like.

Embodiments of the present invention described above and illustrated in the drawings should not be construed as limiting the technical spirit of the present invention. Persons having ordinary knowledge in the technical field of the present invention can change and change the technical idea of the present invention in various forms, and the improvement and change are within the protection scope of the present invention as long as it is obvious to those skilled in the art. Will belong.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the invention described in the claims below. It will be appreciated that it can be changed.

Claims (10)

Represented by the formula (Ba _1-y M _y ) _3-x SiO ₅ : Eu ²⁺ _x (0 <x ≤ 1, 0 ≤ y ≤ 0.9, M is at least one selected from the group consisting of Sr, Ca and Mg) Barium silicate-based phosphor. The method according to claim 1, M is Ca or Mg, y is 0 ≤ y ≤ 0.5 barium silicate-based phosphor. Forming a mixture of barium carbonate (BaCO ₃ ), silica (SiO ₂ ), and europium oxide (Eu ₂ O ₃ ); Drying the mixture; And Heat-treating the dried mixture to form barium silicate represented by the formula Ba _{3 - x} SiO ₅ : Eu ^{2 +} _x (0 <x ≤ 1). The method according to claim 3, The mixture comprises a material having at least one alkaline earth metal (M) selected from the group consisting of Sr, Ca and Mg, wherein the barium silicate is (Ba _1-y M _y ) _3-x SiO ₅ : Eu ²⁺ _x A method for producing a barium silicate-based phosphor represented by the formula (0 <x ≤ 1, 0 ≤ y ≤ 0.9, M is at least one selected from the group consisting of Sr, Ca, and Mg). The method according to claim 3, The heat treatment is carried out in a reducing atmosphere, a method of producing a barium silicate-based phosphor using a gas mixed with hydrogen gas 2 to 25% by weight. The method according to claim 3, The heat treatment temperature is a method of producing a barium silicate-based phosphor of 800 ~ 1600 ℃. Light emitting diodes having a main peak wavelength of 400 to 470 nm; And Excited by the light emitted from the light emitting diode, (Ba _1-y M _y ) _3-x SiO ₅ : Eu ²⁺ _x (0 <x ≤ 1, 0 ≤ y ≤ 0.9, M is Sr, Ca and Mg White light emitting device comprising a barium silicate-based phosphor represented by the formula of at least one selected from the group consisting of. The method according to claim 7, The light emitting diode is a blue light emitting diode having a main peak wavelength of 460nm, the light excited by the phosphor has a wavelength band of 500 ~ 700nm. The method according to claim 7, The light emitting diode is a long wavelength infrared light emitting diode having a main peak wavelength of 405nm, the light excited by the phosphor has a wavelength band of 450 ~ 700nm. Excited by light emitted from the light emitting diode, and (Ba _1-y M _y ) _3-x SiO ₅ : Eu ²⁺ _x (0 <x ≤ 1, 0 ≤ y ≤ 0.9, M being Sr, Ca and Mg A light emitting film comprising a barium silicate-based phosphor represented by the formula of at least one selected from the group consisting of.

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