KR20170134179A - Phosphor and manufacturing method thereof, and light emitting device using the phosphor - Google Patents

Abstract

Provided are a phosphor of which an initial light emitting intensity maintenance rate is improved, and a light emitting device using the phosphor. The phosphor of the present invention is a silicofluoride phosphor, wherein an intensity ratio I_(IR) of an intensity I_2 of a maximum peak existing in a range of 3,570 to 3,610 cm^-1 to an intensity I_1 of a maximum peak existing in a range of 1,200 to 1,240 cm^-1 in an infrared ray absorption spectrum is 0.01 or less; and ECoN of an octahedron which has a center of a site occupied by silicon or manganese and has a site of fluorine as an apex is 5.6-6.0 inclusive when performing a structural analysis process of an X-ray powder diffraction profile by a Rietveld analysis method in conditions that a crystal system is a monoclinic crystal system, and that the crystal system is set to a crystal structure which has a face-centered symmetry with a space group P1.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a phosphor, a method of manufacturing the phosphor, and a light emitting device using the phosphor.

The present invention relates to a phosphor, a method for producing the phosphor, and a light emitting device using the phosphor.

A light emitting diode (LED) light emitting device is mainly composed of a combination of an LED chip and a phosphor as an excitation light source, and can emit light of various colors depending on the combination thereof.

In a white LED light emitting device that emits white light, a combination of an LED chip and a phosphor emitting light in the blue region is used. For example, a combination of an LED chip emitting blue light and a phosphor mixture may be mentioned. As the fluorescent material, a yellow light-emitting fluorescent material that emits yellow light, which is a complementary color of blue, is used, and is used as a pseudo white light LED light-emitting device. In addition, a three-wavelength type white LED in which an LED chip emitting blue light, a green-yellow light-emitting fluorescent substance, and a red light-emitting phosphor are used has been developed. A K ₂ SiF ₆ : Mn phosphor is known as one of the red light emitting phosphors used in such a light emitting device.

In the conventionally known fluorophosphors, when light is continuously excited to emit light, the light emission intensity after a lapse of time tends to be lower than the initial light emission intensity. When the phosphor is used in a light emitting device, it is preferable that the change in the light emission intensity with time is small, that is, the light emission intensity retention rate is high. For this reason, it is desired to improve the luminescence intensity retention rate of the phosphor. In order to meet such a demand, there is a report that the surface of the phosphor is treated with a treatment liquid containing a surface treating agent such as an organic amine or an ammonium salt to improve the durability in a high temperature and high humidity test. However, in such a method, it is necessary to carry out a step of further performing a treatment on the phosphor synthesized once, and another method is required to suppress the production cost of the phosphor. In addition, since a conventionally known fluorophosphor phosphor generally tends to lower its light emission intensity when it comes into contact with moisture, it is not preferable to carry out surface treatment using a treatment agent containing such moisture after synthesis.

Japanese Patent Publication No. 2009-528429 Japanese Patent Application Laid-Open No. 2014-141684

It is an object of the present invention to provide a phosphor improved in luminescence intensity maintenance ratio without lowering the luminescence intensity of the phosphor and a luminescent device using such a phosphor.

The phosphor according to the embodiment has a composition represented by the following formula (A):

_{(K 1-p / k,} M p / k) a (Si 1-xy, Ti x, Mn y) F b (A)

(here,

M is at least one species selected from the group consisting of Na and Ca,

k is the number of the mantissa of M, which is 1 or 2,

1.5? A? 2.5,

5.0? B? 6.5,

0? P / k? 0.1,

0? X? 0.3, and

0 < y? 0.06

being)

Lt; RTI ID = 0.0 >

I _IR = I ₂ of the intensity I ₂ of the maximum peak in the range of 3570 to 3610 cm ^-1 with respect to the intensity I ₁ of the maximum peak existing in the range of 1200 to 1240 cm ^{-1 in} the infrared absorption spectrum / I ₁ is not less than 0 and not more than 0.01, and

The powder X-ray diffraction profile was measured for a crystal structure having an octahedral structure centering on a site occupied by silicon or manganese and having a peak at the site of fluorine, , An effective coordination number ECoN defined by the following general formula (B) when an average crystal structure is determined by Rietveld analysis under the conditions set in the crystal structure having

(Wherein w _i is represented by the following formula (C);

Wherein, l _i is six silicon (or manganese) in the octahedron - a combined length of the combination of the second of the bond between the fluorine, i (i = 1, 2 , 3, 4, 5, 6), l av is less than Represented by the general formula (D);

In the formula, 1 _min represents the minimum value among the six silicon (or manganese) -fluorine bond lengths of the octahedron)

Is not less than 5.6 but not more than 6.0.

The light emitting device according to the embodiment is characterized by comprising a light emitting element that emits light having a peak in a wavelength range of 440 nm to 470 nm and a phosphor layer containing the phosphor.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram showing an infrared absorption spectrum of a phosphor according to an embodiment. FIG.
2 is an enlarged view of an infrared absorption spectrum (800 to 1600 cm ^-1 ) of a phosphor according to an embodiment.
3 is an enlarged view of an infrared absorption spectrum (2500 to 4000 cm ^-1 ) of a phosphor according to an embodiment before and after dehydration treatment.
4 is a graph showing the relationship between the effective coordination number ECoN of phosphors and the internal quantum efficiency according to the embodiment;
5 is a cross-sectional view of a light emitting device according to an embodiment.
6 is a sectional view of a light emitting device according to another embodiment;

Hereinafter, the embodiments will be described in detail. The embodiments described below represent a phosphor and a light-emitting device for embodying the technical idea of the present invention, and the present invention is not limited to the following examples.

The inventors of the present invention have conducted intensive studies and studies on manganese-activated phosphors mainly containing potassium suicide. As a result, it has been found that a specific peak of an infrared absorption spectrum of a phosphor (hereinafter also referred to as an IR spectrum) The intensity ratio and the specific crystal structure are correlated with the luminescence efficiency of the phosphor and the luminescence intensity retention rate of the phosphor.

In an embodiment, a preferable phosphor is one represented by the following general formula (A).

_{(K 1-p / k,} M p / k) a (Si 1-xy, Ti x, Mn y) F b (A)

(Wherein,

M is at least one species selected from the group consisting of Na and Ca,

k is the number of the mantissa of M, which is 1 or 2,

1.5? A? 2.5,

5.0? B? 6.5,

0? P / k? 0.1,

0? X? 0.3, and

0 < y? 0.06

being)

The phosphor according to the embodiment contains manganese as an activator. In order to convert this phosphor into a red light emitting phosphor, it is preferable that the valence of manganese is +4. Manganese of another valence may be contained, but it is preferable that the ratio is small, and most preferably all manganese is +4.

In the case where manganese is not contained (y = 0), light emission can not be confirmed even when excited by light having an emission peak in an ultraviolet to blue region. Therefore, it is necessary that x in the general formula (A) is larger than 0. Further, when the content of manganese is large, the light emitting efficiency tends to be improved, and y is preferably 0.005 or more.

However, when the content of manganese is excessively large, a concentration quenching phenomenon occurs, and the emission intensity of the phosphor tends to become weak. In order to avoid such a problem, the content ratio (y) of manganese is preferably 0.06 or less, and more preferably 0.05 or less.

Further, as described above, the phosphors according to the embodiments may contain elements other than K, Si, F and Mn which are the main constituent elements. As the element to be contained, for example, a small amount of Na, Ca, Ti or the like may be contained. Even when these elements are contained in a small amount, the phosphors exhibit a similar luminescence spectrum in the red region, and a desired effect can be achieved. However, the content of these elements is preferably small in view of the stability of the phosphor and the cost of synthesizing the reactive phosphor when synthesizing the phosphor. In addition, an element other than those exemplified here may be contained as an inevitable component in some cases. Even in such a case, the effects of the embodiment are generally exhibited.

In addition, the phosphor according to the embodiment may contain an abnormal phase or an impurity in addition to the main phase. At this time, it is preferable that not only the composition of the whole phosphor but also the composition of the main phase satisfies the above general formula (A).

In order to analyze the content of each element with respect to the whole phosphor, for example, the following method can be mentioned. The synthesized phosphor is alkali-melted by a metal element such as K, Na, Ca, Si, Ti and Mn, and is irradiated with ICP light emission (for example, by IRIS Advantage type ICP emission spectrochemical analyzer (trade name, manufactured by Thermo Scientific Inc.) It can be analyzed by spectroscopy. The non-metallic element F can be analyzed by, for example, a DX-120 type ion chromatograph analyzer (trade name, manufactured by Dio Nex Co., Ltd.), by separating the synthesized phosphor by thermal hydrolysis. The analysis of F can also be performed by ion chromatography after alkali melting as in the case of the above-described metal elements.

In addition, the phosphor according to the embodiment does not contain oxygen stoichiometrically. However, oxygen may inevitably be incorporated into the phosphor during the synthesis process of the phosphor or after decomposition of the surface of the phosphor after synthesis. Although the content of oxygen in the phosphor is preferably 0, it is preferable that the ratio of [oxygen content] / [(fluorine content) + (oxygen content)] is less than 0.05, since the luminous efficiency is not significantly damaged.

Conventionally, when a fluorophosphor phosphor having a basic structure containing potassium, silicon and fluorine and activated with manganese is used as a light emitting device, when the light emitting device is continuously operated, the light emission intensity of the phosphor decreases Resulting in a color shift of light emission. There are many ways to solve this problem, but there was room for improvement. On the other hand, the inventors of the present invention have found that exhibiting excellent IR spectra among these phosphors exhibit excellent properties. Specifically, the intensity of the maximum peak present in the IR spectrum at 3570 to 3610 cm ^-1 against the intensity of the maximum peak present at 1200 to 1240 cm ^-1 (hereinafter sometimes referred to as I ₁ ) It represents the following, I ₂ d is in) the _{non-I IR (I 2 / I 1} ) having excellent characteristics are 0.01 or less in the case of the phosphor.

The intensity ratio of the IR spectrum is considered to correspond to the content of various OH groups present in the phosphor. That is, as described later, the peak present at 3570 to 3610 cm ^-1 corresponds to the natural vibration of the OH bond of the isolated OH group, and the peak near 3200 cm ^-1 of the OH bond contained in the water molecule It is assumed that it corresponds to natural vibration. It is considered that the phosphor exhibits excellent characteristics when the intensity ratio in the IR spectrum of the phosphor is within a specific range, that is, when the OH bond contained in the phosphor is small.

The method of measuring the IR spectrum is not particularly limited, but can be measured by an infrared spectrometer such as a VERTEX 70V FT-IR spectrometer (trade name, manufactured by Bruker Optics Co., Ltd.). The measurement conditions may be, for example, as follows.

Wavelength resolution: 4 cm ^-1

Sample Scan Count: 100 times

Measured wave range: 350 to 4000 cm ^-1

Measuring Atmosphere: Vacuum

Detector: TGS (DTGS) detector

The IR spectrum measurement method includes a transmission method, a reflection method, an ATR method, and the like. The phosphor according to the present embodiment is generally a powder having a particle diameter of several mu m to 60 mu m, It is preferable to perform it by a diffuse reflection method. The diffuse reflection method is generally carried out by diluting a light-permeable diluent such as KBr or KCl in an infrared region at an appropriate concentration (about 1 to 10%). In the IR spectrum of the phosphor of the present embodiment, Since the peak intensities around 3590 cm ^{-1 and} around 3220 cm ^-1 are small, it is preferable to perform the measurement without using the diluent. However, in the background measurement, it is preferable to perform the measurement using the diluent.

Fig. 1 shows an example of the IR spectrum of the phosphor according to the present embodiment. Fig. 2 is an enlarged view of the IR spectrum of Fig. 1 at 800 to 1600 cm <" ^{1 &} gt ;. 2 also shows an IR spectrum of a K ₂ SiF ₆ powder in which Mn is not activated (for example, a commercial Sakae reagent manufactured by Kanto Kagaku). 2, peaks at 800 to 1600 cm < ^-1 > are observed at almost the same positions in the Mn-activated phosphor and the K ₂ SiF ₆ powder not activated by Mn. In this respect, it is considered that the peak near 800 to 1600 cm ^-1 in the Mn-activated phosphor corresponds to the vibration mode inherent to the matrix K ₂ SiF ₆ crystal.

3 is an enlarged view of the IR spectrum of FIG. 1 at 2500 to 4000 cm ^-1 . 3, it can be seen that almost no peak is detected in this range in the phosphor of the embodiment. On the other hand, in the conventional silicon fluoride phosphors in which the internal dehydration treatment of particles is not carried out, it is general that there is a vibration peak in such a range. That is, in the case of producing the phosphor according to the embodiment, it is preferable to form a phosphor crystal in an aqueous medium and then dehydrate the inside of the specific phosphor particle (detailed later). In the phosphors before the dewatering treatment in the inside of the phosphor particles, a sharp vibration peak can be observed in the vicinity of 3720, 3630 and 3590 cm ^-1 . Further, a broad vibration peak at 2500 to 3500 cm ^-1 is confirmed. The oscillation peak of the electron is considered to be a peak inherent in the isolated OH group present in the phosphor. The latter broad vibration peak is considered to be a peak attributed to the OH bond included in the water molecule adsorbed to the phosphor crystal, hydrogen bond or coordination bond. The present embodiment is completed on the basis of the knowledge that the sharp maximum peak intensity (I ₂ ) existing at 3570 to 3610 cm ^-1 correlates with the characteristics of the phosphor.

However, since the IR measurement is generally used for qualitative evaluation, it is difficult to quantitatively evaluate the sharp maximum peak existing at 3570 to 3610 cm ^-1 , and the correlation between the peak intensity and the characteristics of the phosphor is specified It is difficult to do. Therefore, in the embodiment, with reference to the maximum peak, present in the 1200 to 1240㎝ ^-1 is considered to be attributable to a natural oscillation mode of K ₂ SiF ₆ determined in the resulting IR spectrum 3570 to 3610 for it, The relative intensity (I _IR = I ₂ / I ₁ ) of the maximum peak present at ^-1 was taken as an index.

In addition, the above-mentioned maximum peak position (wavenumber) in the IR spectrum may vary depending on the composition of the phosphor and the synthesis conditions of the phosphor. In the present embodiment, the peak position near 1220 cm ^-1 is an important factor. The peak position may fluctuate by about ± 15 cm ^-1 under the preferable condition and about ± 5 cm ^-1 under the more preferable condition.

Further, in order to perform measurement in a wide wave number range, it is preferable to use a TGS (DTGS) detector having high response linearity.

In the present embodiment, when the phosphor is used for a light emitting device when the relative intensity I _IR value is 0.01 or less, the change of the light emission intensity with the lapse of time during continuous operation is small, that is, It was found out. In the present embodiment, detailed reasons why the phosphor exhibits excellent characteristics when the relative intensity I _IR is in the above-described range are not sufficiently clarified. However, it is estimated as follows. When a fluorescent material having a general fluoride as a matrix is incorporated in a light emitting device, the fluorescent material becomes hot by operation, and as a result, hydrolysis involving the isolated OH group contained in the fluorescent material occurs, . On the other hand, in the phosphor according to the embodiment, since the content of the isolated OH group is small, it is presumed that the hydrolysis does not occur and the decrease in the emission intensity is also reduced.

The relative intensity I _IR is preferably 0.01 or less, more preferably 0.005 or less, and still more preferably 0.002 or less. Most preferably, there is no peak in the range of 3570 to 3610 cm ^-1 , that is, I ₂ = I _IR = 0.

The phosphors according to the embodiments can be produced by any method, for example, by the method described below.

The phosphor having the composition represented by the general formula (A) can be obtained by dissolving, in an aqueous solution of hydrofluoric acid in which a mixture of hexafluorosilicic acid (H ₂ SiF ₆ ), potassium hexafluoromanganate (K ₂ MnF ₆ ), sodium hexafluoromanganate, The potassium-containing raw material is added and reacted, and the like. In addition, a method in which a Si source and a Ti source are reacted in an aqueous solution of hydrofluoric acid with potassium permanganate or the like, or a method in which a potassium source is added to a solution in which hexafluorosilicic acid and potassium hexafluoromanganate (K2MnF6) It can be synthesized by a precipitation method or the like. In either production method, the basic phosphor can be obtained by synthesizing it in an aqueous solution using hydrofluoric acid, followed by drying treatment such as suction filtration.

According to the investigations of the present inventors, it has been found that, even in the case of a phosphor after drying treatment such as suction filtration, water molecules adsorbed on the isolated OH group or the surface of the phosphor are inevitably contained in the phosphor. It is possible to reduce the content of water contained in the isolated OH group or the phosphor to some extent by selecting the synthesis method or optimizing the synthesis parameters, but it is not easy to completely remove the isolated OH group or the water molecule by the examination of the synthesis method. Therefore, in order to remove the isolated OH group or the water molecules, after the synthesis of the above-mentioned basic phosphor and, if necessary, the drying treatment is carried out, dehydration treatment is performed inside the phosphor particles to remove the isolated OH group or water molecule can do. The dehydration treatment inside the phosphor particles is preferably carried out at a temperature in the range of 200 ° C to 800 ° C, a pressure range of 0.0003 to 8 atm, and a treatment time of 1 minute to 24 hours. More preferably not lower than 200 ° C and not higher than 750 ° C, not lower than 0.01 atm and not higher than 6 atm, not lower than 5 but not higher than 10 hours. The atmosphere in which the dehydration process is performed in the inside of the phosphor particles can be performed in nitrogen, argon, helium, fluorine atmosphere or the like.

However, if dehydration treatment is performed inside the excess phosphor particles to remove the isolated OH group or water molecule and lower the I _IR value, it is considered that a part of the phosphor is denatured or oxidized. It has been common that phosphor formed in an aqueous medium is not actively heated or subjected to dehydration treatment in the inside of the particle by depressurization or the like for reasons of avoiding denaturation or oxidation. In the embodiment, in order to avoid denaturation or oxidation of such a phosphor, it is possible to control by adjusting the temperature, pressure and atmosphere in the dehydration process inside the synthesized phosphor particles.

Fig. 4 shows the relationship between the effective coordination number ECoN of the phosphor and the internal quantum efficiency. Here, the effective coordinate number ECoN is a physical quantity indicating deformation of the coordinated polyhedron. For example, when the crystal structure is a perfect octahedron, there is no deformation, and ECoN is 6. ECoN becomes smaller as the crystal structure is deformed, and smaller as the strain becomes larger. Specifically, the ECoN is a crystal structure having an octahedral structure in which a site occupied by silicon or manganese is at the center and a site of fluorine is the apex, and the powder X-ray diffraction profile is an equation (B) when the average crystal structure is determined by Rietveld analysis under the condition set to a crystal structure having face-center symmetry, in which the space group is P1.

(Wherein w _i is represented by the following formula (C);

Wherein, l _i is six silicon (or manganese) in the octahedron - a combined length of the combination of the second of the bond between the fluorine, i (i = 1, 2 , 3, 4, 5, 6), l av is less than Represented by the general formula (D);

In the formula, 1 _min represents the minimum value among the six silicon (or manganese) -fluorine bond lengths of the octahedron)

In addition, the powder X-ray diffraction profile to be analyzed is an actual value, and the crystal to be measured may contain an abnormal phase or an impurity in addition to the main phase represented by the above general formula (A). When the measured powder X-ray diffraction profile has a distinctly different shape from the known columnar phase, the profile shape (peak) not corresponding to the columnar phase is excluded, because the content thereof is relatively small and therefore generally negligible Can be interpreted.

Further, the absorption coefficient of the phosphor and the internal quantum efficiency? 'Are calculated by the following equations.

Wherein,

E (?): The total spectrum of the excitation light source irradiated onto the phosphor (converted to photon number)

R (?): The excitation light source reflected light spectrum of the phosphor (converted to photon number)

P (?): Emission spectrum of phosphor (converted to photon number)

to be.

The absorption coefficient of the phosphor and the internal quantum efficiency can be measured by, for example, a C9920-02G absolute PL quantum yield measuring apparatus (trade name, manufactured by Hamamatsu Photonics K.K.). As the excitation light when the matrix coloring is measured, a peak wavelength of about 650 nm and a half width of 5 to 10 nm can be used. As the excitation light for measuring the internal quantum efficiency, blue light having a peak wavelength in the vicinity of 440 to 470 nm and a half width of 5 to 15 nm can be used.

Further, in order to use the phosphor according to the embodiment for a light-emitting device or the like, the internal quantum efficiency is preferably 70% or more. It can be seen from Fig. 4 that when the ECoN is increased, the internal quantum efficiency is increased. In order to achieve an internal quantum efficiency of 70% or more, the ECoN is preferably 5.6 or more, more preferably 5.8 or more. By definition, the maximum value of ECoN is 6.0. 4, it can be seen that the higher the ECoN of the phosphor represented by the general formula (A), the higher the quantum efficiency. Therefore, it is preferable that ECoN is high. In order to achieve such a high ECON, various methods can be taken. As one method for achieving a high ECON, it is preferable to optimize the dehydration condition inside the phosphor particles.

The phosphors according to the embodiments may be classified according to the application method to the light emitting device to be used. In general white LEDs or the like using excitation light having an emission peak in the blue region, it is preferable to use phosphor particles classified generally in the range of 1 to 50 mu m. If the particle diameter of the fluorescent substance after classification is excessively small, the emission intensity may be lowered. In addition, when the particle diameter is excessively large, phosphors are clogged in the phosphor layer coating apparatus when applied to an LED, which may result in lowering of working efficiency and yield, and color irregularity of the completed light emitting device.

The phosphor according to the embodiment is excited by an excitation light source having an emission peak in the ultraviolet to blue region. When this phosphor is used for a light emitting device, it is preferable to use, as an excitation light source, a light emitting element having an emission peak in a wavelength range of 440 nm to 470 nm from the excitation spectrum of the phosphor. It is not preferable from the viewpoint of light emission efficiency to use a light emitting element having an emission peak outside the wavelength range described above. As the light emitting element, a solid light source element such as an LED chip or a laser diode can be used.

The phosphor according to the embodiment is a phosphor that emits red light. Therefore, when blue light is used for the excitation light source, a white light emitting device can be obtained by using the green light emitting phosphor and the yellow light emitting phosphor in combination. When ultraviolet light is used for the excitation light source, a white light emitting device can be obtained by using the blue light emitting phosphor in combination with the green light emitting phosphor and the yellow light emitting phosphor. The kind of the phosphor to be used may be arbitrarily selected in accordance with the purpose of the light emitting device. For example, when providing a white light emitting device for illumination with a low color temperature, a light emitting device having both efficiency and color rendering property can be provided by combining the phosphor according to the embodiment and the yellow light emitting phosphor.

The green light-emitting fluorescent substance and the yellow light-emitting fluorescent substance may be referred to as a fluorescent substance having a main emission peak in a wavelength range of 520 nm to 570 nm. Such as phosphor, for example, (Sr, Ca, Ba) 2 SiO 4: Eu, Ca 3 (Sc, Mg) 2 Si 3 O 12: silicate phosphor, such as _{Ce (Y, Gd) 3 (} Al, Ga ) ₅ O _12: activate Eu, Eu: Ce, etc. of the aluminate phosphor, (Ca, Sr, Ba) Ga 2 S 4: Eu , etc. of the sulfide phosphor, (Ca, Sr, Ba) Si 2 O 2 N 2 Alkaline earth oxynitride phosphors such as (Ca, Sr) -? SiAlON,? SiAlON, and the like. The main luminescence peak is a wavelength at which the peak intensity of the luminescence spectrum is the largest, and the luminescence peak of the exemplified phosphor has been reported so far in the literature. Further, a slight change in the emission peak of about 10 nm is recognized due to the addition of a small amount of element or slight compositional variation during the production of the phosphor. Such a phosphor is also included in the above-exemplified phosphor.

The blue light-emitting fluorescent substance may be a fluorescent substance having a main emission peak in a wavelength region of 440 nm to 500 nm. For example, (Sr, Ca, Ba, Mg) 5 (PO 4) 3 (Cl, Br): Eu, (Sr, Ca, Ba, Mg) 5 (PO 4) (3Cl): halo phosphate such as Eu Phosphor, a phosphor such as 2SrO · 0.84P ₂ O ₅ · 0.16B ₂ O ₃ : Eu, and an alkaline earth metal aluminate phosphor such as BaMgAl ₁₀ O ₁₇ : Eu.

In the light emitting device using the phosphor according to the embodiment, the orange light-emitting fluorescent substance and the red light-emitting fluorescent substance other than those described above may also be used depending on the use.

Examples of the orange-emitting phosphor, a red light-emitting fluorescent material _{(Sr, Ca, Ba) 2} SiO 4: silicate phosphor, Li, such as Eu (Eu, Sm) tungstate fluorescent material such as _{W 2 O 8, (La,} Gd, Y) 2 O ₂ S: oxysulfide phosphor such as Eu, (Ca, Sr, Ba ) S: Eu , etc. of the sulfide phosphor, (Sr, Ba, Ca) 2 Si 5 N 8: Eu, (Sr, Ca) AlSiN 3: Eu , etc. And the like. By using these phosphors in combination with the phosphors according to the embodiments, it is possible to further improve not only the efficiency but also the color rendering property in illumination use and the color area in backlight use. However, if the number of the used phosphors is excessively large, the phosphors absorb and emit light, and the reabsorption and luminescence phenomenon or scattering phenomenon occur, and the light emitting efficiency of the light emitting device is lowered.

Fig. 5 shows a cross section of the light emitting device according to the embodiment. In the illustrated light emitting device, the light emitting device has a lead 100, a lead 101 and a stem 102, a semiconductor light emitting element 103, a reflecting surface 104, and a phosphor layer 105. At the center of the bottom, the semiconductor light emitting element 103 is mounted by Ag paste or the like. As the semiconductor light emitting element 103, ultraviolet light emission or light emission in a visible region can be used. For example, it is possible to use a semiconductor light emitting diode such as a GaAs-based or GaN-based semiconductor. The arrangement of the lead 100 and the lead 101 can be appropriately changed. In the concave portion of the light emitting device, the phosphor layer 105 is disposed. This phosphor layer 105 can be formed by dispersing the phosphor according to the embodiment in a resin layer containing, for example, a silicone resin at a ratio of 5 wt% or more and 80 wt% or less.

As the semiconductor light emitting element 103, a flip chip type having an n-type electrode and a p-type electrode on the same plane can be used. In this case, problems caused by wires such as disconnection and peeling of wires and light absorption by wires are solved, and a semiconductor light emitting device with high reliability and high luminance can be obtained. Further, an n-type substrate may be used for the semiconductor light emitting element 103 so as to have the following structure. Specifically, an n-type electrode is formed on the back surface of the n-type substrate, a p-type electrode is formed on the top surface of the semiconductor layer on the substrate, and an n-type electrode or a p-type electrode is mounted on the lead. The p-type electrode or the n-type electrode can be connected to the other lead by a wire. The size and shape of the semiconductor light emitting element 103 and the dimensions and shape of the concave portion can be appropriately changed.

Fig. 6 shows an example of a shell-type light emitting device. The semiconductor light emitting device 201 is mounted on the lead 200 'with the mount material 202 interposed therebetween and is covered with the pre-dipping material 204. The lead 200 is connected to the semiconductor light emitting element 201 by the bonding wire 203 and is sealed with the casting material 205. The pre-dipping material 204 contains a phosphor according to the embodiment.

As described above, the light emitting device according to the embodiment, for example, the white LED is optimal not only for general illumination but also for a light emitting device used in combination with a color filter or the like, for example, a light source for a liquid crystal backlight. Specifically, it can be used as a red light emitting material of an inorganic electroluminescence device using a backlight light source of a liquid crystal or a blue light emitting layer.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples unless the scope of the invention is exceeded.

[Example 1, Comparative Example 1]

After the KMnO ₄ powder and the KF powder were dissolved in the HF aqueous solution, the H ₂ O ₂ aqueous solution was slowly added dropwise, and the K ₂ MnF ₆ was synthesized by sufficiently reacting in the HF aqueous solution. The synthesized K ₂ MnF ₆ was subjected to suction filtration to obtain a K ₂ MnF ₆ powder. Further, the SiO ₂ powder was dissolved in the HF aqueous solution to adjust the H ₂ SiF ₆ solution. Further, the KF powder was dissolved in the HF aqueous solution to adjust the KF aqueous solution. The K ₂ MnF ₆ powder synthesized in the adjusted H ₂ SiF ₆ solution was dissolved to adjust the reaction solution. K ₂ SiF ₆ : Mn was synthesized by dripping a previously prepared KF aqueous solution into the prepared reaction solution and sufficiently reacting in the reaction solution. The synthesized K ₂ SiF ₆ : Mn was subjected to suction filtration to obtain a phosphor powder (Comparative Example 1). The composition analysis of the synthesized fluorescent material was analyzed and found to _{K 2. 03 (Si 0.98, Mn} 0.02) F 6. Further, in order to completely remove isolated OH groups and water molecules from the synthesized phosphors, dehydration treatment was performed inside the phosphor particles (Example 1).

IR spectra of Example 1 and Comparative Example 1 were measured. The intensity I _IR of the maximum peak in the range of 3570 to 3610 cm ^-1 with respect to the intensity of the maximum peak in the range of 1200 to 1240 cm ^-1 in the infrared absorption spectra of Example 1 and Comparative Example 1, The quantum efficiency was as shown in Table 1.

For the IR spectrum measurement, a VERTEX70V FT-IR spectrometer (trade name, manufactured by Bruker Optics Co., Ltd.) was used. The detection limit of I _IR by this apparatus is 0.001, and when it is below the detection limit, it is described as 0.001 or less in Table 3.

After these samples were ground in a mortar, powder X-ray diffraction measurement was carried out using SmartLab (trade name, manufactured by Rigaku). The measurement was carried out using concentration method and the 2? Was swept in the range of 5 to 140 占 폚. The obtained powder X-ray diffraction profile was defined as a crystal structure having a face-centered symmetry with a polynomial of unity and a space group of P1, with the atomic coordinates shown in Table 1 as an initial structure. PDXL II (trade name, manufactured by Rigaku Corporation) ) To perform the Rietveld analysis, and the average structure was refined. The a-axis length, b-axis length and c-axis length of the average crystal structure at this time were 8.1419 Å, and α, β and γ were 90.000 °. The R factors indicating the convergence of interpretation were Rwp of 5.39 and S of 1.40.

Also, Table 1 corresponds to the fractional coordinate of the ideal octahedral structure determination. That is, the coordinates of each element of the unit lattice can be obtained by expanding the partial coordinates in Table 1 as belonging to the space group P1 and by developing it according to the symmetry of the space group. From the results shown in Table 1, the effective coordination number ECoN in the crystal structure of the octahedron centering on the Si / Mn site and having six F sites as apexes was calculated based on the above-mentioned formula. At this time, the value of the effective coordination number ECoN was 6.

Table 2 shows the atomic coordinates of the crystals obtained in Example 1 obtained after the analysis of the powder X-ray diffraction profile. The a-axis length, the b-axis length and the c-axis length of the average crystal structure at this time were 8.1130 (7) A, 8.152 (2) A, and 8.142 ), 90.14 (3), and 90.06 (3) degrees, respectively.

From the results shown in Table 2, the effective coordination number ECoN of the octahedron centering on the Si / Mn site and having six F sites as apexes was calculated based on the above-mentioned formula. The results are shown in Table 3.

The phosphors of Example 1 and Comparative Example 1 were mixed together with a resin and sealed on a GaN-based LED light-emitting device to obtain a light-emitting device. For each light emitting device, current was injected into each LED, and the light emitting device was continuously lit. The behavior of the luminescent intensity of the phosphors of Example 1 and Comparative Example 1 was observed. The retention ratios of luminescence intensity after 500 hours and after 1000 hours were as shown in Table 3. From these results, it can be understood that in the phosphor according to the embodiment, the decrease in light emission intensity is suppressed when the light emitting device is used.

Next, phosphors were synthesized in the same manner as in Comparative Example 1, and phosphors of Examples 2 to 6 in which drying conditions were changed were synthesized. I _IR , ECoN and internal quantum efficiency in the phosphor were as shown in Table 3. In addition, the phosphors of Examples 2 to 6 were mixed together with the resin, and the luminescence intensity retention ratio of the light-emitting device sealed on the GaN-based LED light-emitting device was as shown in Table 3.

From these results, it is the I _IR 0.01 or less, and high, the internal quantum efficiency is sufficient for practical use or more ECoN is 0.56, it can be seen that at the same time the light emission intensity retention ratio is also high.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other forms, and various omissions, substitutions, and alterations can be made without departing from the gist of the invention. These embodiments and their modifications fall within the scope and spirit of the invention, and are included in the scope of the invention as defined in the claims and their equivalents.

100 and 101: Lead
102: Stem
103: Semiconductor light emitting element
104: Reflecting surface
105: phosphor layer
200 and 200 ': lead
201: Semiconductor light emitting element
202: Mount material
203: Bonding wire
204: pre-dipping material
205: casting material

Claims (9)

(A): < EMI ID =
_{(K 1-p / k,} M p / k) a (Si 1-xy, Ti x, Mn y) F b (A)
(here,
M is at least one species selected from the group consisting of Na and Ca,
k is the number of the mantissa of M, which is 1 or 2,
1.5? A? 2.5,
5.0? B? 6.5,
0? P / k? 0.1,
0? X? 0.3, and
0 < y? 0.06
being)
Lt; RTI ID = 0.0 &gt;
I _IR = I ₂ of the intensity I ₂ of the maximum peak in the range of 3570 to 3610 cm ^-1 with respect to the intensity I ₁ of the maximum peak existing in the range of 1200 to 1240 cm ^{-1 in} the infrared absorption spectrum / I ₁ is not less than 0 and not more than 0.01, and
The powder X-ray diffraction profile was measured for a crystal structure having an octahedral structure centering on a site occupied by silicon or manganese and having a peak at the site of fluorine, , An effective coordination number ECoN defined by the following general formula (B) when an average crystal structure is determined by Rietveld analysis under the conditions set in the crystal structure having
[Equation 1]

(Wherein w _i is represented by the following formula (C);
&Quot; (2) &quot;

Wherein, l _i is six silicon (or manganese) in the octahedron - a combined length of the combination of the second of the bond between the fluorine, i (i = 1, 2 , 3, 4, 5, 6), l av is less than Represented by the general formula (D);
&Quot; (3) &quot;

In the formula, 1 _min represents the minimum value among the six silicon (or manganese) -fluorine bond lengths of the octahedron)
Is 5.6 or more and 6.0 or less. The method according to claim 1,
The I _IR is less than zero or 0.005, the phosphor. 3. The method according to claim 1 or 2,
In the general formula (A), p / k = 0 and x = 0. 4. The method according to any one of claims 1 to 3,
And the internal quantum efficiency? 'Of the phosphor is 70% or more. Characterized by comprising a light emitting element which emits light having a peak in a wavelength region of 440 nm or more and 470 nm or less and a phosphor layer containing a phosphor according to any one of Claims 1 to 4, . 6. The method of claim 5,
Wherein the phosphor layer further comprises a phosphor having an emission peak in a wavelength range of 520 nm to 570 nm. A process for producing a phosphor according to any one of claims 1 to 4,
(A) (i) a process for producing a silicon carbide thin film comprising the steps of: (i) combining a Si-containing raw material and a Ti-containing raw material with potassium permanganate and sodium permanganate in the presence of an aqueous solution of hydrofluoric acid; (ii) A coprecipitation method in which a potassium-containing raw material and a sodium-containing raw material are added to an aqueous solution of hydrofluoric acid in which a mixture with sodium is dissolved, or a step
(B) a step of dehydrating the phosphor synthesized in (A) above in an inert gas at a temperature of 200 ° C or more and 800 ° C or less
To form a phosphor. 8. The method of claim 7,
Wherein the step of dewatering the inside of the phosphor is performed at a pressure of 0.0003 to 8 atm. 9. The method according to claim 7 or 8,
Wherein the inert gas is nitrogen, argon, or helium gas.

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