TW201935720A - [beta]-sialon fluorescent material, production method therefor, and light emitting device - Google Patents

Abstract

This [beta]-sialon fluorescent material satisfies 2.5 > Y/X wherein X is the photoelectron intensity at a bonding energy of 103.5 eV in an X-ray photoelectron spectrum obtained using Al-K[alpha] radiation as an excitation X-ray source, and Y is the photoelectron intensity at a bonding energy of 102.0 eV.

Description

Beta-type Cylon phosphor, manufacturing method thereof, and light emitting device

The present invention relates to a β-sialon phosphor, a method for manufacturing the same, and a light emitting device.

The light-emitting device that combines a light-emitting element that emits primary light and a phosphor that absorbs primary light and emits secondary light is the next generation that can expect low power consumption, miniaturization, high brightness, and wide-range color reproducibility Light-emitting devices have attracted attention, and research and development are prevailing. For example, a light-emitting device has been proposed which combines a light-emitting element and a phosphor which emit visible light of a short wavelength from blue to purple in combination, and utilizes the light-emitting element's light emission and the color mixing of the light after the wavelength conversion of the phosphor. White light was obtained (Patent Document 1).

In recent years, light-emitting devices such as backlights, lighting, and flat-panel displays of liquid crystal displays have been required to have high brightness, and high-output light-emitting devices have been accompanied by progress. Since the high output of the light-emitting device is associated with an increase in the amount of heat generation, the light-emitting intensity decreases as the temperature of the phosphor increases, which may cause the reliability of the light-emitting device to decrease. For this reason, the pursuit of a phosphor excellent in durability (especially heat resistance) has attracted attention as a nitride or oxynitride phosphor represented by a β-sialon phosphor having a stable crystal structure.

As for a method for producing a β-Sialon phosphor, it is known to mix silicon nitride, aluminum nitride, and an optically active element compound such as hafnium oxide at a predetermined molar ratio, and perform the process at a temperature of about 2000 ° C. A method of sintering and pulverizing the obtained sintered material, and then subjecting the powdered sintered material to acid treatment (Patent Document 2). Further, a method of performing a heat treatment in a nitrogen atmosphere and a heat treatment in a rare gas environment after sintering the raw materials is also known (Patent Document 3).

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 4769132

[Patent Document 2] Japanese Patent No. 4210761

[Patent Document 3] Japanese Patent No. 5508817

However, the β-sialon phosphor manufactured by a known method such as Patent Documents 2 and 3 has insufficient durability (especially heat resistance) while maintaining the same state. When a phosphor is used in a light-emitting device, there is a problem that reliability is reduced.

The present invention aims to provide a β-sialon phosphor capable of manufacturing a light-emitting device with high reliability and a method for manufacturing the same.

Another object of the present invention is to provide a light-emitting device with high reliability.

As a result of intensive research to solve the above-mentioned problems, the inventors of the present case found that by modifying the surface of the β-sialon phosphor by heat treatment under specific conditions and performing surface modification, it is possible to obtain luminescence that imparts high reliability. The β-sialon phosphor having excellent durability (especially heat resistance) of the device has completed the present invention.

Furthermore, the inventors have performed X-ray photoelectron spectroscopic analysis on a β-sialon phosphor having the above characteristics, and found that the X-ray photoelectron spectroscopic spectrum using an Al-Kα line as an excitation X-ray source specifically The ratio of the photoelectron intensity (Counts / s) in the binding energy of the two positions is within a specific range, and even the present invention is completed.

That is, in the β-sialon phosphor according to the embodiment of the present invention, in the X-ray photoelectron spectroscopy spectrum in which Al-Kα rays are used as the excitation X-ray source, the photoelectron intensity when the binding energy is 103.5 eV is set When X is X and the photoelectron intensity when the binding energy is 102.0 eV is set to Y, 2.5> Y / X is satisfied.

A light-emitting device according to an embodiment of the present invention includes the above-described β-sialon phosphor.

In addition, the method for producing a β-sialon phosphor according to an embodiment of the present invention is such that, in a coexisting state of water with a total mass of β-sialon phosphor and water of 0.5% by mass or more, the temperature is 150 ° C or more The β-sialon phosphor is heat-treated at a temperature of approximately 50 ° C.

According to the present invention, a β-sialon phosphor capable of manufacturing a highly reliable light-emitting device and a method for manufacturing the same can be provided.

Further, according to the present invention, a highly reliable light emitting device can be provided.

FIG. 1 is an X-ray photoelectron spectroscopic spectrum of a β-sialon phosphor of Example 1 and Comparative Example 1. FIG.

2 is a spectrum of a value (KM value) of a Kubelka-Munk Function measured by FT-IR of β-sialon phosphors of Example 1 and Comparative Examples 1 to 2. FIG.

Hereinafter, the β-sialon phosphor of the present invention, a method for manufacturing the same, and embodiments of a light emitting device will be described in detail. However, the present invention is not limited to the following embodiments, and the constituent elements can be modified and embodied without departing from the gist thereof. In addition, various inventions can be formed by a suitable combination of a plurality of constituent elements disclosed in the following embodiments. For example, several constituent elements may be removed from all the constituent elements shown in the embodiment. Furthermore, constituent elements of different embodiments may be appropriately combined.

The "β-sialon phosphor" in this specification refers to a solid solution in which the Si position of β-type silicon nitride (Si ₃ N ₄ ) is partially replaced by Al and the N position is partially replaced by O, and It can be represented by the general formula: Si _6-z Al _z O _z N _8-z . In the formula, z is 0 ~ 4.2. In addition, the β-sialon fluorescent system is excited in a wide wavelength region from ultraviolet to visible light to emit green light.

In the β-sialon phosphor of this embodiment, in an X-ray photoelectron spectroscopy spectrum in which an Al-Kα line is used as an excitation X-ray source, the photoelectron intensity at a binding energy of 103.5 eV is set to X, and When the photoelectron intensity at 102.0 eV is set to Y, 2.5> Y / X is satisfied. when When 2.5 ≦ Y / X, the durability of the β-sialon phosphor is not sufficiently improved, so a highly reliable light-emitting device cannot be obtained.

Here, the X-ray photoelectron spectroscopy spectrum specifies a functional group or the like by the value of the binding energy of each photoelectron intensity. The photoelectron intensity at a binding energy of 103.5 eV indicates a Si-N bond, and the photoelectron intensity at a binding energy of 102.0 eV indicates a Si-O bond.

It can be considered that when 2.5> Y / X is satisfied, since the ratio of the Si-O bond to the Si-N bond becomes high, the surface of the β-sialon phosphor is hydrolyzed to sufficiently form an oxide layer (that is, the surface Modifications are fully carried out). When an oxide layer is sufficiently formed on the surface of the β-sialon phosphor, further hydrolysis is suppressed. As a result, when the temperature of the β-sialon phosphor in the light-emitting device rises, since the generation of ionic substances such as ammonium ions is suppressed, the reliability of the light-emitting device is improved.

X-ray photoelectron spectroscopy spectrum can be obtained by X-ray photoelectron spectroscopy (XPS). The measurement conditions are as follows.

Measuring device: X-ray photoelectron spectroscopic analysis device (ULHI-PHI, Inc. PHI5000VersaProbeII)

Output: 15kV-50W

Measurement area: 200μmΦ

Pass energy: 187eV

Step: 50ms

The β-sialon phosphor of this embodiment is preferably a value (KM value) of a Kubelka-Munk (hereinafter referred to as "KM") function using FT-IR In the spectrum, when the KM value at a wave number of 3650 cm ^-1 is set to A and the KM value at a wave number of 2600 cm ^-1 is set to D, 0.15 <A / D is satisfied.

Here, the "value of the Kuberka-Munk function" in this specification refers to a function that converts the reflectance of a substance into a value that is a characteristic absorption index inherent to a substance, and is capable of dividing the absorption coefficient by the scattering coefficient (absorption coefficient). / Scattering coefficient).

In the spectrum system using the value of the Kuberka-Munk function of FT-IR (KM value), the functional group can be specified by the value of the wave number. The KM value at a wave number of 3650 cm ^-1 indicates a Si-OH bond, and the KM value at a wave number of 2600 cm ^-1 indicates a peak derived from the structure of a β-Sialon phosphor.

It can be considered that when the ratio of 0.15 <A / D is satisfied, since the ratio of Si-OH bonds occupied by the structure of the β-sialon phosphor becomes high, the surface of the β-sialon phosphor is hydrolyzed to form an oxide layer sufficiently. (That is, the surface modification is sufficiently performed). Therefore, as a result of further suppressing the hydrolysis of the β-sialon phosphor, as the temperature of the β-sialon phosphor in the light-emitting device rises, it becomes difficult to generate ionic substances such as ammonium ions, which makes the light-emitting device Improved reliability.

The spectrum of the value of the Kuberka-Munk function (KM value) can be obtained by Fourier transform infrared absorption analysis (FT-IR). The measurement system was performed using Spectrum One manufactured by PerkinElmer Japan Co., Ltd. The measurement sample may be pelletized without diluting the β-sialon phosphor.

The β-sialon phosphor of this embodiment preferably has a KM when the wave number is 3650 cm ^-1 in a spectrum using a value of the Kuberka ^- Munk function of FT-IR (KM value). When the value is set to A and the KM value is set to B when the wave number is 3400 cm ^-1 , 0.2 <A / B is satisfied.

Here, the KM value when the wave number is 3400 cm ^-1 indicates an OH bond that adsorbs water.

It can be considered that when 0.2 <A / B is satisfied, since the ratio of the Si-OH bond of the oxide layer becomes higher than that of the OH bond that adsorbs water, the surface of the β-sialon phosphor is hydrolyzed to form an oxide layer . Therefore, when the temperature of the β-sialon phosphor in the light-emitting device rises, it becomes difficult to generate ionic substances such as ammonium ions, and the reliability of the light-emitting device is improved.

The β-sialon phosphor of this embodiment preferably has a KM when the wave number is 3200 cm ^-1 in a spectrum using a value of the Kuberka-Munk function of FT-IR (KM value). When the value is set to C and the KM value is set to B when the wave number is 3400 cm ^-1 , 0.7 <C / B is satisfied.

Here, the KM value when the wave number is 3200 cm ^-1 indicates the Al-OH bond of the oxide layer.

It can be considered that when 0.7 <C / B is satisfied, the ratio of the Al-OH bond of the oxide layer is higher than that of the O-H bond that adsorbs water, so the surface of the β-sialon phosphor is hydrolyzed to form an oxide layer sufficiently. Therefore, when the temperature of the β-sialon phosphor in the light-emitting device rises, it becomes difficult to generate ionic substances such as ammonium ions, and the reliability of the light-emitting device is improved.

The β-sialon phosphor of this embodiment having the above-mentioned characteristics can coexist in a state in which the total mass of water relative to the β-sialon phosphor and water is 0.5% by mass or more. The β-sialon phosphor is heat-treated to produce it. When the amount of coexisting water is less than 0.5% by mass or the heating temperature is less than 150 ° C, the surface hydrolysis of the β-sialon phosphor becomes insufficient, and an oxide layer is not sufficiently formed.

Combining water with β-sialon phosphor and water The method of counting the coexistence state of 0.5% by mass or more is not particularly limited. For example, after the β-sialon phosphor and water are mixed, the mixture (water content of 0.5% by mass or more) may be closed. .

Although the pressure conditions during the heat treatment are not particularly limited, it is preferable to perform the heat treatment at a gauge pressure of 0.05 MPa or more. By performing the heat treatment under the pressure conditions described above, the surface of the β-sialon phosphor can be efficiently hydrolyzed. The method for performing the heat treatment under such a pressure condition is not particularly limited, and for example, a closed container can be used and the heat treatment can be performed in a closed state.

The β-sialon phosphor before the heat treatment is not particularly limited as long as it is obtained by a known method. Specifically, the β-sialon fluorescent system before the heat treatment described above can be obtained by sintering a mixed raw material powder containing silicon nitride, aluminum nitride, and an optically active element compound such as hafnium oxide, and sintering the obtained material. Obtained by crushing. In addition, the β-sialon phosphor before the heat treatment may be subjected to an acid treatment and a heat treatment in an inactive environment as necessary. As the β-sialon phosphor before the heat treatment, a commercially available product may be used.

After the heat treatment described above, it can be further heat-treated in the atmosphere at 100 ° C or higher, preferably 100 to 600 ° C. By performing further heat treatment, since the adsorbed water and crystal water of the β-sialon phosphor can be removed, the reliability of the light emitting device is improved.

The β-sialon phosphor of this embodiment obtained in this manner is useful for use in a light-emitting device because it is difficult to generate ionic substances such as ammonium ions when the temperature in the light-emitting device rises.

The light-emitting device of this embodiment includes the above-mentioned β-type race Long fluorescent. In this light emitting device, a β-sialon phosphor is generally used as a light emitting member. The light-emitting member can be obtained by mixing and curing a β-sialon phosphor with a sealing material (for example, a silicone resin). The light emitting member may contain a phosphor other than the β-sialon phosphor.

The light-emitting device of this embodiment may include various light-emitting elements. The light emitting element is not particularly limited, but is preferably an ultraviolet LED or a blue LED that emits light having a wavelength of 240 to 480 nm, and more preferably a blue LED that emits light having a wavelength of 440 to 470 nm. For example, a white light emitting device (white LED) can be obtained by combining the above-mentioned β-sialon phosphor with an ultraviolet LED or a blue LED.

The light-emitting device of the present embodiment having the above-mentioned features has high reliability because it contains a β-sialon phosphor that is unlikely to generate ionic substances such as ammonium ions when the temperature inside the light-emitting device rises.

[Example]

Hereinafter, the present invention will be described more specifically using examples and comparative examples. However, the present invention is not limited to the following examples as long as the present invention is not deviated from the gist thereof.

(Example 1)

95% by mass of β-sialon phosphor (GR-SW529B manufactured by Denka Co., Ltd.) was mixed with 5% by mass of ion-exchanged water. Next, after putting 20 g of the mixture into a SUS316 container (50cc) with Teflon (registered trademark) as a substrate inside, heat treatment was performed at a temperature of 200 ° C. for 168 hours in a closed state. The gauge pressure in the container during the heat treatment was measured to be 1.62 MPa. Second, cast the heat-treated β-sialon phosphor while The ion-exchanged water was passed through a nylon sieve (mesh 150 μm), and then filtered using filter paper having a pore size of 10 μm or less. The filtered matter was washed with 3 L of ion-exchanged water and filtered again, and then dried at 80 ° C. for 25 hours to obtain a β-sialon phosphor of Example 1.

(Example 2)

A β-sialon phosphor of Example 2 was obtained, except that the heat treatment was performed at 200 ° C. for 48 hours. The gauge pressure in the container during the heat treatment was measured to be 1.62 MPa.

(Example 3)

The β-sialon phosphor of Example 2 was further heat-treated at 150 ° C. for 5 hours in the atmosphere to obtain the β-sialon phosphor of Example 3.

(Example 4)

The β-sialon phosphor of Example 2 was further heat-treated at 80 ° C. for 5 hours in the atmosphere to obtain the β-sialon phosphor of Example 4.

(Example 5)

Except that the heat treatment was performed at 150 ° C. for 48 hours, the treatment was performed under the same conditions as in Example 1 to obtain the β-sialon phosphor of Example 5. The gauge pressure during the heat treatment was measured to be 0.52 MPa.

(Example 6)

A β-sialon phosphor (GR-SW529B, manufactured by Denka Co., Ltd.) was mixed with 99.5% by mass and 0.5% by mass of ion-exchanged water, and treated under the same conditions as in Example 2 to obtain the product of Example 6. β-sialon phosphor. The gauge pressure during heat treatment was measured to be 0.68 MPa.

(Comparative example 1)

A β-sialon phosphor (GR-SW529B manufactured by Denka Co., Ltd.) before the heat treatment was used as Comparative Example 1.

(Comparative example 2)

A β-Sialon phosphor (GR-SW529B manufactured by Denka Co., Ltd.) was heat-treated in the atmosphere at 200 ° C. for 168 hours. Next, the heat-treated β-sialon phosphor was passed through a nylon sieve (mesh 150 μm) while being poured with ion-exchanged water, and then filtered using filter paper having a pore size of 10 μm or less. The filtered matter was washed with 3 L of ion-exchanged water and filtered again, and then dried at 80 ° C. for 25 hours to obtain a β-sialon phosphor of Comparative Example 2.

(Comparative example 3)

A β-sialon phosphor of Comparative Example 3 was obtained, except that the heat treatment was performed at 100 ° C. for 48 hours, and treated under the same conditions as in Example 1. The gauge pressure during heat treatment was measured to be 0.13 MPa.

(Comparative Example 4)

A β-sialon phosphor of Comparative Example 4 was obtained, except that the heat treatment was performed at 50 ° C. for 48 hours, and treated under the same conditions as in Example 1. The gauge pressure during heat treatment was measured to be 0.02 MPa.

(Comparative example 5)

A β-sialon phosphor (GR-SW529B, manufactured by Denka Co., Ltd.) was mixed with water and 20 g of a β-sialon phosphor was used. The same conditions as in Example 2 were used to obtain The β-sialon phosphor of Comparative Example 5. The gauge pressure during heat treatment was measured to be 0.06 MPa.

The heat treatment conditions in the above examples and comparative examples are summarized in Table 1.

X-ray photoelectron spectroscopy, Fourier transform infrared absorption analysis, and reliability evaluation were performed on the β-sialon phosphors obtained in the above examples and comparative examples.

X-ray photoelectron spectroscopy and Fourier transform infrared absorption analysis were performed under the conditions described above. The reliability evaluation was performed as follows.

<Reliability Evaluation>

2.5 g of β-Sialon phosphor obtained in the examples and comparative examples and 47.5 g of a polysilicone resin (OE6656, manufactured by Dow Corning Toray Co., Ltd.) were converted into a mixer (manufactured by THINKY Corporation) AWATORI RENTARO (registered trademark) ARE-310). Next, a light emitting element (LED) is arranged on the bottom of the concave package body and wire bonding is performed on the substrate. Then, the mixture is injected from a micro syringe so as to cover the light emitting element, and the mixture is injected at 150 ° C. Of hardening. Thereafter, a post cure was performed at 110 ° C. for 10 hours, and then sealed to prepare an LED package. As the light-emitting element, a light-emitting peak wavelength of 448 nm and a size of 1.0 mm × 0.5 mm were used.

Next, the LED package connected to the DC stabilized power supply was placed in a constant temperature and humidity tank at 85 ° C. and 85% RH and turned on at 90 mA for 1,000 hours of exposure. The total beam of the LED package before and after the exposure was measured, and the total beam retention of the LED package after the exposure was calculated. When the total beam holding ratio is 93% or more, it can be determined that the reliability is high.

The results of each evaluation described above are shown in Table 2.

Here, the X-ray photoelectron spectroscopy spectrum of the β-sialon phosphor of Example 1 and Comparative Example 1 is shown in FIG. 1 as a representative example of the results of the X-ray photoelectron spectroscopic analysis and the Fourier transform infrared absorption analysis. The spectra of the values of the Kuberka-Munk function (KM value) of the β-sialon phosphors of Example 1 and Comparative Examples 1 to 2 are shown in FIG. 2.

As shown in Table 2, in the β-sialon fluorescent system 2.5> Y / X in Examples 1 to 6, a highly reliable LED package having a full beam retention rate of 93% or more can be obtained.

On the other hand, since the β-sialon phosphor of Comparative Example 1 was not heat-treated, an oxide layer was not sufficiently formed on the surface, and became 2.5 ≦ Y / X (the ratio of the Si—O bond to the Si—N bond becomes lower). As a result, it is considered that this β-sialon phosphor generates ionic substances such as ammonium ions when the temperature rises, and the total light beam retention (reliability) of the LED package is reduced.

Since the β-sialon phosphor of Comparative Example 2 was heat-treated in the atmosphere, the surface hydrolysis was not sufficiently performed. In addition, the β-sialon phosphors of Comparative Examples 3 and 4 did not sufficiently undergo surface hydrolysis because the heat treatment temperature was too low. In addition, the β-sialon phosphor of Comparative Example 5 had not been set in a coexisting state of 0.5 mass% or more of water with respect to the total mass of the β-sialon phosphor and water during the heat treatment. The hydrolysis was not sufficiently carried out. Therefore, it can be considered that an oxide layer is not sufficiently formed on the surface of these β-sialon fluorescent systems, and becomes 2.5 ≦ Y / X (the ratio of the Si-O bond to the Si-N bond becomes lower), and the full beam of the LED package is maintained. The rate (reliability) is reduced.

In addition, after comparing Example 2 and Example 3, after the heat treatment, further heat treatment was performed in the atmosphere at a temperature of 100 ° C. or higher, so that the total light beam retention rate (reliability) of the LED package was improved. This is considered to be because the adsorbed water of the β-sialon phosphor was removed by further heat treatment. After actually observing the spectrum (KM value) of the Kubeka-Munk function, it shows that the KM value B of the O-H bond of the adsorbed water decreases and the values of A / B and C / B increase.

Even if further heat treatment is performed, when the heat treatment temperature is less than 100 ° C. as in Example 4, the effect of improving the full beam retention (reliability) of the LED package is not sufficiently obtained.

From the above results, according to the present invention, it is possible to provide a β-sialon phosphor capable of producing a highly reliable light-emitting device and a method for producing the same. Further, according to the present invention, a highly reliable light emitting device can be provided.

[Industrial availability]

The β-sialon phosphor of the present invention can be used for white A variety of light-emitting devices, such as light-emitting devices and colored light-emitting devices. Examples of the white light-emitting device include a liquid crystal display, a backlight of a liquid crystal panel, a lighting device, a signal device, and a video display device. The β-sialon phosphor and light-emitting device of the present invention can also be used as a projector.

Claims (9)

A β-Sialon phosphor is an X-ray photoelectron spectroscopy using an Al-Kα line as an excitation X-ray source. The photoelectron intensity at a binding energy of 103.5 eV is set to X and the binding energy is 102.0 When the photoelectron intensity at eV is set to Y, 2.5> Y / X is satisfied. For example, the β-sialon phosphor of claim 1, wherein the KM value when the wave number is 3650 cm ^-1 in the spectrum using the value of the Kuberka ^- Munk function of FT-IR (KM value) When it is set to A and the KM value when the wave number is 2600 cm ^-1 is set to D, 0.15 <A / D is satisfied. For example, the β-sialon phosphor of claim 1, wherein the KM value when the wave number is 3650 cm ^-1 in the spectrum using the value of the Kuberka ^- Munk function of FT-IR (KM value) When it is set to A and the KM value when the wave number is 3400 cm ^-1 is set to B, 0.2 <A / B is satisfied. For example, the β-sialon phosphor of claim 2, in which the KM value when the wave number is 3650 cm ^-1 in the spectrum using the value of the Kuberka ^- Munk function of FT-IR (KM value) When it is set to A and the KM value when the wave number is 3400 cm ^-1 is set to B, 0.2 <A / B is satisfied. The β-sialon phosphor according to any one of claims 1 to 4, wherein the wave number is 3200 cm in the spectrum using the value of the Kuberka-Munk function of FT-IR (KM value). When the KM value at ^-1 is set to C and the KM value at a wave number of 3400 cm ^-1 is set to B, 0.7 <C / B is satisfied. A light emitting device comprising a β-sialon phosphor according to any one of claims 1 to 5. A method for manufacturing a β-sialon phosphor is based on the coexistence of water with a total mass of 0.5% by mass or more relative to the β-sialon phosphor and water. The light body is heat-treated. For example, the method for producing a β-sialon phosphor according to claim 7, wherein the heat treatment is performed at a gauge pressure of 0.05 MPa or more. The method for manufacturing a β-sialon phosphor according to claim 7 or 8, wherein the heat treatment is further performed in the atmosphere at a temperature of 100 ° C or higher after the aforementioned heat treatment.