KR101449639B1 - Silicon oxynitride phosphor, method of fabricating the same and light device having the same - Google Patents

Abstract

The present invention relates to a silicon oxynitride phosphor, a method of manufacturing the same, and an optical device including the same. A silicon oxynitride phosphor according to an embodiment of the present invention includes a silicon oxynitride phosphor containing a compound represented by the following Formula 1 that is irradiated by an excitation light source and emits light:
[Chemical Formula 1]
Sr _{2 - z} Si (O _{1 - x} N _x ) ₄ : zEu ^{2 +}
0 < x < 1 and 0 < z &lt;

Description

TECHNICAL FIELD [0001] The present invention relates to a silicon oxynitride phosphor, a method of manufacturing the same, and an optical device including the silicon oxynitride phosphor.

The present invention relates to a phosphor mainly composed of a silicon compound, and more particularly to a silicon oxynitride phosphor, a method for producing the phosphor, and an optical device including the phosphor.

BACKGROUND ART [0002] Recently, research on an illumination device or an image display device using a solid-state light emitting device such as a semiconductor light emitting diode has been extensively carried out. Among the above lighting devices, a white light emitting diode (LED) is attracting attention as a next-generation high-efficiency lighting device that replaces a conventional incandescent lamp or a fluorescent lamp because electrons and holes combine to emit light. The white LED can be used not only for energy saving based on the efficiency but also for the use of a material having a high environmental load such as mercury and can be installed in a narrow space because the lamp can be downsized, Its application range is long.

A conventional white light emitting diode lamp is composed of a light emitting diode element that emits short wavelength light in the blue region and a phosphor that emits a long wavelength of yellow light by being excited by absorbing a part or all of the light. In this case, the white light is obtained by mixing the blue light generated by the blue light emitting diode and the yellow light generated by the excited phosphor. In the conventional yellow light emitting fluorescent material, there is a garnet fluorescent material consisting of yttrium and aluminum activated by cerium. In this case, white light is obtained by mixing blue light near 450 nm of the blue LED chip and yellow light of about 560 nm of the fluorescent material . However, the white light obtained in this way lacks the red component, and it is difficult to improve the color rendering property of the illumination. Also, due to the lack of such red components, it is difficult to obtain a white lighting device having a low color temperature similar to that of a bulb.

As another method for obtaining the illumination device having improved color rendering properties and a low color temperature, a small amount of red phosphor may be mixed with the yellow phosphor, or a green phosphor and a red phosphor may be used instead of the yellow phosphor. In this case, development of a red phosphor having excellent color purity is required. However, the red phosphor generally has a lower efficiency than the green or blue phosphor because it has a relatively low excitation spectrum in the ultraviolet band or the blue band, and is required to be mixed in a relatively large proportion (60 wt% or more) in the entire phosphor . In addition, the red phosphor needs to have excellent temperature stability in order to ensure long lifetime and high output power to an optical element such as an illumination element and a display element.

SUMMARY OF THE INVENTION The present invention provides a red light emitting phosphor which has high light emitting efficiency and excellent temperature stability while providing high purity and high luminance red light for improving color rendering.

Another technical problem to be solved by the present invention is to provide a method for producing a silicon oxynitride phosphor having the above-described advantages.

It is another object of the present invention to provide various optical devices using the silicon oxynitride phosphors having the above-described advantages.

According to an aspect of the present invention, there is provided a silicon oxynitride phosphor comprising a compound represented by the following general formula (1), which is irradiated by an excitation light source and emits light.

[Chemical Formula 1]

Sr _{2 - z} Si (O _{1 - x} N _x ) ₄ : zEu ^{2 +}

0 < x < 1 and 0 < z &lt;

According to another aspect of the present invention, there is provided a silicon oxynitride phosphor comprising a compound represented by Chemical Formula 2, which is irradiated by an excitation light source and emits light.

(2)

Sr _{2 - y - z} M _y Si (O _{1 - x} N _x ) ₄ : zEu ^{2 +}

Wherein M is any one of Ca, Ba and Mg, or a combination thereof,

0 <x <1, 0 <y <2, 0 <z? 0.4, 0 <y + z <2

According to another aspect of the present invention, there is provided a method of fabricating a silicon nitride phosphor, comprising: mixing precursor compositions having the formula SrCO ₃ , Si ₃ N _4, and Eu ₂ O ₃ ; And heat-treating the mixed resultant to form a compound represented by Formula 1.

In another embodiment, the method of manufacturing the silicon nitride phosphor is, SrCO _3, Si ₃ N ₄ and mixing the precursor composition and the metal M oxide, nitride, nitrate, carbonate, hydroxide or chloride having the formula of Eu ₂ O ₃ ; And heat-treating the mixed resultant to form a compound represented by Formula 2.

According to another aspect of the present invention, there is provided an optical device including: an excitation light source that emits light belonging to at least one of a near ultraviolet region, an ultraviolet region, and a blue region; And the silicon oxynitride phosphor which is arranged and emits light by being irradiated with the light.

 According to the embodiment of the present invention, it is possible to improve the color rendering property by providing red light of high purity and high luminance, and by selecting the ultraviolet ray, Or an oxynitride phosphor having a wide emission band from the green region to the red region can be provided. Further, according to the embodiment of the present invention, a red light emitting phosphor capable of controlling the position and intensity of the main emission wavelength of the red band can be provided.

Further, according to the embodiment of the present invention, a manufacturing method capable of reliably manufacturing a red light-emitting phosphor having the above-described advantages is provided. In addition, white light having excellent color rendering property is realized by mixing white light with a part of the light emitted from an arbitrary light source and the wavelength-converted light emitted by the excited red light-emitting phosphor, as well as the red light using the red light- Can be provided.

FIG. 1 is a graph showing the relationship between the X value of Sr _{2 - z} Si (O _{1 - x} N _x ) ₄ : zEu ^{2 +} when the heat treatment temperature of the SSON according to Example 1 of the present invention is 1,400 ° C., 1,500 ° C., 1,600 ° C., Ray diffraction (XRD) analysis.
2 is Sr ₂ SiO ₄ in the case where the heat treatment temperature of each SSON according to the first embodiment of the present invention is 1,400 ℃, 1,500 ℃, 1,600 ℃ and 1,700 ℃: excitation of Eu ^{2 +;} is (photoluminescence excitation PLE) spectrum.
3A to 3C are emission spectra of samples according to the embodiments of the present invention and the comparative example excited by light sources having wavelengths of 320 nm, 377 nm, and 466 nm, respectively.
4 is a graph showing the ratio of the emission intensity at 477 nm and the emission intensity at 610 nm (R _em ) of the SSON compound according to the heat treatment temperature changes when the excitation wavelengths are 320 nm and 377 nm, respectively.
FIG. 5 is a graph showing X-ray diffraction analysis results of samples obtained at a heat treatment temperature of 1,700 ° C. of SSON compounds, SMSON compounds, SCSON compounds, and SBSON compounds according to various embodiments of the present invention.
6 is a photoluminescence excitation (PLE) spectrum of the SSON compound, SMSON compound, SCSON compound and SBSON compound according to Example 2 of the present invention at a heat treatment temperature of 1700 ° C.
7A to 7C are emission spectra of SSON compounds, SCSON compounds, and SBSON compounds according to an embodiment of the present invention excited by electromagnetic waves having wavelengths of 320 nm, 377 nm and 466 nm, respectively.
8 is a graph showing the excitation spectra of the SSON compounds having different Eu ^{2 +} concentration in accordance with an embodiment of the invention. Curve a to the curve d is a measurement result of the SSON compound each having a 0.5 mol%, 1.0 mol%, 5 mol%, and 10 mol% Eu ^{2 +} concentration.
Figure 9 is at an excitation wavelength of 377 nm is a graph showing the emission spectrum of the SSON compounds according to the concentration change of Eu ^{2 +.}
Figure 10 is an excitation wavelength of 466 nm from a graph showing the emission spectrum of the SSON compounds according to the concentration change of Eu ^{2 +.}
11 is a graph showing a change in red light emission intensity with temperature change of an SSON compound according to an embodiment of the present invention.
12 is a cross-sectional view schematically showing a capsule illumination device as an optical device according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, It is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more faithful and complete, and will fully convey the scope of the invention to those skilled in the art.

In the following drawings, thickness and size of each layer are exaggerated for convenience and clarity of description, and the same reference numerals denote the same elements in the drawings. As used herein, the term "and / or" includes any and all combinations of any of the listed items.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" include singular forms unless the context clearly dictates otherwise. Also, &quot; comprise "and / or" comprising "when used herein should be interpreted as specifying the presence of stated shapes, numbers, steps, operations, elements, elements, and / And does not preclude the presence or addition of one or more other features, integers, operations, elements, elements, and / or groups.

Although the terms first, second, etc. are used herein to describe various elements, components, regions, layers and / or portions, these members, components, regions, layers and / It is obvious that no. These terms are only used to distinguish one member, component, region, layer or section from another region, layer or section. Thus, a first member, component, region, layer or section described below may refer to a second member, component, region, layer or section without departing from the teachings of the present invention.

In the luminescent region used in this specification, the green region in the blue region is a wavelength region band of approximately 440 nm to 580 nm, the red region in the green region is a wavelength region band of approximately 490 nm to 750 nm, the red region in the blue region is approximately 440 nm It can be said to be a wavelength range band of 750 nm.

The present application is related to "Synthesis and Luminescent Properties of (Sr, M) ₂ Si (O ₁ )", published in Journal of The Electrochemical Society, published Feb. 28, 2012, _{? x N x) 4: Eu} 2 + (M: Mg 2 +, Ca 2 +, Ba 2 +) , and on the basis of the paper of "is unloading, the articles are included herein in their entirety by this as a reference, the Should be regarded as part of the specification.

The silicon oxynitride phosphor according to embodiments of the present invention is a non-stoichiometric solid solution and is a compound represented by the following formulas. Hereinafter, the compound represented by the following formula (1) is referred to as an SSON compound.

[Chemical Formula 1]

Sr _2-z Si (O _1-x N _x ) ₄ : zEu ²⁺ ,

0 < x < 1 and 0 < z &lt;

The phosphor compound according to another embodiment of the present invention may include a compound represented by the following general formula (2) in which part or all of Sr of the above-mentioned phosphor compound is substituted with an alkali metal such as Ca, Ba, and Mg have.

(2)

Sr _{2- y} Z M _y Si (O _1-x N _x ) ₄ : zEu ²⁺

Wherein M is any one of Ca, Ba and Mg, or a combination thereof,

0 <x <1, 0 <y <2, 0 <z? 0.4, and 0 <y + z <2.

Hereinafter, in this specification, when M is _{Ca Sr 2 - y Ca y Si} 2 (O 1 - x N x) 4: Eu 2 + a SCSON compound, when the _{Ba Sr 2 - y Ba y Si} 2 (O 1 _{- x} N _x ) ₄ : Eu ^{2 +} is an SBSON compound, and when Mg is Sr _{2 - y} Mg _y Si ₂ (O _{1 - x} N _x ) ₄ : Eu ^{2 +} is referred to as an SMSON compound.

 The excitation light source may have an ultraviolet ray region of 300 nm to 330 nm, a near ultraviolet ray region of 370 nm to 410 nm and a blue visible ray region of 450 nm to 470 nm, and in the following embodiments, The wavelengths of 320 nm, 377 nm and 466 nm belonging to the above are exemplary and the present invention is not limited thereto. That is, it is to be understood that the emission characteristics at an excitation wavelength of 320 nm are representative of the emission characteristics obtained at other wavelengths of the ultraviolet region, and it is to be understood that not only the above exemplified wavelength but also all of the listed wavelength bands are included in the scope of the present invention .

Hereinafter, the features and advantages of the present invention will be described with reference to the analysis results of the sample manufactured according to the embodiment of the present invention.

The SSON compound, the SCSON compound, the SBSON compound, and the SMSON compound according to the embodiment of the present invention can be easily prepared by mixing a certain amount of solid raw materials and performing a heat treatment at a high temperature for a long time. A precursor of each element contained in Formula 1 is prepared by the solid phase method. The precursor may be a carbonate, a nitrate, a hydroxide, or a chloride of each element. Preferably, as the precursor, a carbonate of Sr, a nitride of Si, and an oxide of Eu can be used. For example, the carbonate of Sr may be SrCO ₃ , the nitride of Si may be Si ₃ N ₄ , and the oxide of Eu may be Eu ₂ O ₃ . The precursors may be provided in powder form. When SiO ₂ was used as the precursor of Si to form the mother silicate, it was confirmed that no stable phase was formed. However, as in the embodiment, when Si ₃ N ₄ is used as a precursor of Si, a crystal phase of a stable silicon oxynitride phosphor is formed.

Although a metal oxide is generally used in the production of a conventional phosphor nitride, in the present invention, an intermediate product is produced using only carbonates and nitrides thereof as precursors of Sr and Si, and then, a silicon oxynitride phosphor A fluorescent agent having a stable phase can be produced. The heat treatment may be performed in a reducing atmosphere for 30 minutes to 20 hours, for example, a nitrogen atmosphere, and the emission characteristic of the red phosphor may be controlled by controlling the nitrogen substitution by the temperature change of the heat treatment. Alternatively, the mixed powder may be heated at a relatively low temperature, for example, 500 [deg.] C, for example, before the sintering process, in order to promote crystal growth while removing impurities such as moisture, organic substances, Lt; 0 &gt; C to 1,000 &lt; 0 &gt; C for 1 hour to 10 hours. The calcining step, and the reducing atmosphere.

The sintered body obtained through the heat treatment may be pulverized into a powder form if necessary and subjected to a washing process. Thus, the compounds may have a? -Phase or? '-Phase or a mixed phase thereof as described later.

In another embodiment, the above-described red light-emitting fluorescent substance can be prepared using precursors of Ca, Ba, or Mg, which are alkali metals, together with the precursor of Sr, to prepare the compound of Formula 2 above. Each precursor of the alkali metals contained in the above formula may be a carbonate, a nitrate, a hydroxide, or a chloride of each element. Unlike the Si precursor, oxides of these metals, such as MgO, may be used as precursors. Likewise, the luminescent characteristics can be controlled through temperature control of the heat treatment in the reducing atmosphere.

The above-described embodiments relate to the solid-phase method, but this is merely illustrative and the present invention is not limited thereto. It will be understood by those skilled in the art that the red light emitting phosphor of the present invention can be produced by a known liquid phase method or vapor phase method.

FIG. 1 is a graph showing the relationship between the heat treatment temperature of the SSON compound according to the first embodiment of the present invention and the Sr ₂ SiO (SiO ₂ ) ratio when the heat treatment temperature is 1,400 ° C. (curve T 1), 1,500 ° C. (curve T 2), 1,600 ° C. (curve T 3), and 1,700 ° C. ₄ is a graph showing the X-ray diffraction (XRD) analysis results of Eu ^{2 +} (curve R). In addition, the X-ray diffraction analysis results of the Fig. 1, JCPDS (Joint Committee on Power Diffraction Standards) β-Sr 2 SiO 4 (# 38-0271) and _{α'-Sr 2 SiO 4 (#} 39-1256) on the card Respectively.

Referring to FIG. 1, β-Sr ₂ SiO ₄ (# 38-0271) and the β-Sr ₂ SiO ₄ (# 38-0271) are obtained when the heat treatment temperature of the SSON compound according to the embodiment of the present invention is 1,400 ° C., 1,500 ° C. and 1,600 ° C. and has almost the same diffraction pattern as that of α'-Sr ₂ SiO ₄ (# 39-1256). However, when the heat treatment temperature is 1700 ° C (curve T4), it can be seen that the SSON compound has the same diffraction pattern as β-Sr ₂ SiO ₄ (# 38-0271). As a comparative example, Sr ₂ SiO ₄ : Also it was the analysis of Eu ^{2 +} (hereinafter referred to curve R, hereinafter SSO), which can be seen has a _{α'-Sr 2 SiO 4 (#} 39-1256) phase. Accordingly, the SSON phosphor according to the heat-treated example 1 at a heat treatment temperature of less than 1,300 ° C to 1,650 ° C including 1,400 ° C, 1,500 ° C and 1,600 ° C is a silicate-based phosphor, β-Sr ₂ SiO ₄ (# 38-0271) And a phase having a crystal structure of? '- Sr ₂ SiO ₄ (# 39-1256).

In addition, the SSON phosphor according to Example 1 heat-treated at 1,650 ° C to 1,800 ° C including 1,700 ° C includes a single phase having a crystal structure of? -Sr ₂ SiO ₄ (# 38-0271). The phase transition from (α '+ β) -SSON (curves T1 to T3) to β-SSON (curve T4) occurs when the heat treatment temperature increases, because the phase transition between α' It is presumed that this is due to the fact that it is very susceptible to the thermal conditions such as temperature because it can be easily generated by displaced transition method without breaking.

The XRD peaks of SSON according to Example 1 were all Sr ₂ SiO ₄ on JCRDS Compared with the peak of the crystal structure, its position is slightly different. This means that Sr ₂ Si (O _1-x N _x ) ₄ , which is a substitution solid, is formed while nitrogen is partially substituted in the oxygen sites of? '- or? -Sr ₂ SiO ₄ and Si ₃ N ₄ is used instead of SiO ₂ . Hereinafter, this embodiment 1 a silicate (nitrido-silicaties) purged with nitrogen according to the Sr ₂ SiO _4: completely which has a similar crystal structure characteristic and Eu ^{2 +,} even if this distinction The description will be made as to those having different light emission characteristics.

FIG. 2 is a graph showing the relationship between the Sr ₂ SiO (SiO _{2) content and the} SiO _{2 content} in the case where the heat treatment temperature of each SSON according to Example 1 of the present invention is 1,400 ° C. (curve a), 1,500 ° C. (curve b), 1,600 ° C. a; (PLE photoluminescence excitation) spectrum of this Eu ^{+ 2} (curve e): _4. These excitation spectra were measured in the wavelength range between 200 nm and 600 nm, which is the visible light region from the ultraviolet region. In all the samples, Eu was added by 0.5 mol% of the total SSON compound.

Referring to Figure 2, Sr ₂ SiO according to Comparative Example _4: Eu ^{2 +} (curve e, or less SSO La hereinafter) in a two here Center coordination number of 10 Eu (I) and the coordination number 9 of Eu (II) Lt; RTI ID = 0.0 &gt; 320 nm &lt; / RTI &gt; and 377 nm. The SSO has a sharp decrease in the excitation intensity toward the long wavelength near 370 nm, for example, above 400 nm. This is because the wavelength corresponding to the excitation energy of the electron pair of SSO is in the ultraviolet region.

In contrast, when the heat treatment temperature of the SSON compound according to Example 1 of the present invention is 1,600 ° C (curve c) and 1,700 ° C (curve d), the position of the PLE peak at 320 nm is the peak of 320 nm Position, but the peak at 377 nm shifts toward the red wavelength, has a broad excitation band, and at the same time has a main excitation band at 400 nm to 480 nm. Other SSON compounds heat treated at low temperatures of 1,400 ° C and 1,500 ° C, represented by curves a and b, are similar to the SSON compounds indicated by curve c and curve d in the XRD pattern, but the PLE intensity is very low. Therefore, it can be seen that sufficient heat energy for the substitution reaction of nitrogen in SSO and the activation of Eu ions is not supplied at temperatures lower than 1,550 ° C including 1400 ° C and 1500 ° C.

However, in the SSON compounds heat-treated at 1,500 ° C to 1,800 ° C, including 1,600 ° C and 1,700 ° C, the nitrogen substitution was successfully performed, and PLE characteristics distinct from SSO compounds are observed as shown in FIG. Substituted nitrogen has a significant effect on the luminescence properties of Eu (II) sites and has less influence on the luminescence properties of Eu (I) sites. This is because the oxygen coordination number of Eu (II) is 9 but the number of oxygen coordination of Eu (I) is 10 and Eu (II) is shorter than the binding length of Eu (I) It is presumed that Eu (II) is influenced relatively more strongly. These features are the basis for deriving a wide screen of the lowest 5d red shift the PLE spectrum of this level of Eu ^{2 +} ion as described below. In addition, as the heat treatment temperature is increased, the PLE strength is increased.

According to an embodiment of the invention, the nitrogen ions inserted into the crystal structure of the SSO compound is huge crystal field separation (large crystal field splitting) the electron cloud spreading effect (nephelauxetic effect due to the covalent bond of the nitrogen ions; lowering the E _c where Ec is the Eu ²⁺ 5d excitation level energy center (centroid energy) of the ions induced to Im), leads to the lowest level of 5d red-shift of the wide area where the PLE spectrum, and Eu ^{2 +} ions, as described above do. As described above, according to the embodiment of the present invention, the excitation wavelength band of Sr ₂ Si (O _{1 - x} N _x ) ₄ obtained by partially replacing nitrogen ions in the oxygen sites of Sr ₂ SiO ₄ is red shifted, The region can, of course, be provided with a phosphor having a broad excitation band having the maximum excitation intensity in a short-wavelength visible light region (blue visible light region).

In recent years, an InGaN-based diode capable of emitting high-luminance light in the near-ultraviolet region and the short-wavelength visible region has been attracting attention, but an economical alternative material is required because of expensive raw materials including rare earths. SSON according to the embodiment of the present invention can be manufactured from a low cost raw material and heat treated at 1,550 ° C to 1,800 ° C including 1,600 ° C and 1,700 ° C to obtain high absorption intensity not only in the near ultraviolet region but also in a short wavelength visible light region Can be obtained. The high absorption intensity of the SSON phosphor can provide an optical device capable of high-luminance light emission with high efficiency.

Table 1 below shows the content of nitrogen and oxygen in the sample powder. Referring to Table 1, in the SSO compound according to the comparative example, the content of oxygen was about 20.6 wt%, but no nitrogen was detected. Considering that the calculated value is 23.9 wt%, this deviation is presumed to be due to the oxygen deficient composition from the stoichiometric composition since the SSO compound prepared was heat-treated in a hydrogen atmosphere. However, SSON compounds according to embodiments of the present invention that were heat treated at 1,600 &lt; 0 &gt; C and 1,700 &lt; 0 &gt; C contain about 2.0 wt% and 1.8 wt% nitrogen, respectively. Such a content can be considered to be substantially the same considering the measurement error, and broadening and redshift of the above-mentioned excitation wavelength can be obtained at 1 wt% to 10 wt% including 2.0 wt%. Although the nitrogen content is substantially the same, the β-SSON powder exhibits a slightly higher PLE intensity than the (α '+ β) -SSON powder.

sample nitrogen
(wt%) Oxygen
(wt%)  Prize SSO compound 0.0 20.6 ? '- Sr ₂ SiO ₄ SSON compound
(1600 [ ^deg.] C.) 2.0 18.6 (? '+? - Sr ₂ Si (O _{1 - x} N _x ) ₄ SSON compound
(1700 [ ^deg.] C) 1.8 17.2 β-Sr ₂ Si (O _{1 - x} N _x ) ₄

3A to 3C are emission spectra of samples according to the embodiments of the present invention and the comparative example excited by light sources having wavelengths of 320 nm, 377 nm, and 466 nm, respectively.

Referring to FIG. 3A, Sr ₂ SiO ₄ : Eu ^{2 +} (curve e) according to a comparative example has an emission spectrum having peaks at 477 nm and 540 nm, which are yellow visible light regions excited by light having a wavelength of 320 nm Can be obtained. The emission peak at 477 nm is due to the Eu (I) site, and the emission peak at 540 nm is due to the Eu (II) site. Eu (I) and Eu (II) are both excited in the case of excitation by light having a wavelength of 320 nm, but since the Eu (I) is more active than Eu (II), the peak at 477 nm is 540 nm .

In contrast, in the case of the SSON compound having a heat treatment temperature of 1,400 ° C (curve a), 1,500 ° C (curve b), 1,600 ° C (curve c) and 1,700 ° C (curve d) according to an embodiment of the present invention, The emission peak at 540 nm is completely eliminated. Instead, in the SSON compound according to the embodiment of the present invention, a new emission peak is generated at 610 nm in the red visible ray region, and the intensity of the emission peak increases as the heat treatment temperature is increased.

As the SSO compound is converted into the SSON compound, the emission peak due to the Eu (II) position is significantly influenced, but the Eu (I) position is hardly affected. As a result, the SSON compound according to an embodiment of the present invention exhibits a broadband PLE spectrum with a wavelength of 477 nm and a red wavelength due to a large shift from 540 nm to 610 nm .

Referring to Figure 3b, according to the comparative example Sr ₂ SiO _4: in Eu ^{2 +} (curve e) is 377 nm when excited by a wavelength of light, the intensity of the luminescent peak at 477 nm is reduced, but, 540 nm The intensity of the luminescent peak is higher than the luminescence peak intensity at 477 nm, unlike the excitation at 320 nm.

However, in the SSON compound according to the embodiment of the present invention, an emission peak at 477 nm and an emission peak at 610 nm are observed as in the case of irradiation with an excitation light source having a wavelength of 320 nm. However, the intensity of the emission peak at 477 nm is reduced by 50% or more, and the intensity of the emission peak at 610 nm can be increased to 200% or more. Further, in the luminescence spectrum of the SSON compound according to the embodiment of the present invention, the emission peak at 540 nm does not appear as described above.

Referring to FIG. 3C, Sr ₂ SiO ₄ : Eu ²⁺ (curve e) according to the comparative example and SSON compound (curve a to curve d) according to the embodiment of the present invention are excited by light having a wavelength of 466 nm, , The peak at 477 nm almost disappeared and the main emission peak at 540 nm and 610 nm, respectively. In the SSON compound, Eu (I) could be excited at an excitation wavelength of 320 to 377 nm, but Eu (I) was excited at an excitation wavelength of 466 nm.

3A to 3C, according to embodiments of the present invention, the SSON compounds (curves a and b) heat-treated at 1,400 ° C to 1,500 ° C have weak emission intensity, In the SSON compound annealed at 1,700 ℃ (curve d), the emission intensity increases with increasing temperature. From this, it can be seen that the nitrogen substitution during the heat treatment at 1,550 ° C to 1,800 ° C including 1,600 ° C and 1,700 ° C has been successfully performed, and the SSO compound has a significant influence on the crystal field as the SSON compound.

Further, in the SSON compound according to the embodiment of the present invention, the emission peak intensity at 477 nm can be controlled by controlling the wavelength range of the excitation light. According to the embodiment of the present invention, it can be seen that the excitation by light with a wavelength of 466 nm has sufficient energy to eliminate the contribution by Eu (I). Therefore, in the case of the SSON compound, when excitation light of the blue band is used rather than the ultraviolet band, the light emission characteristics of a long wavelength can be obtained. However, when the SSON compound is excited by a near-ultraviolet LED having an emission characteristic of an ultraviolet region or a near-ultraviolet region, preferably a near-ultraviolet region, the SSON compound exhibits a luminescent characteristic having a wide band from a blue region to a red region.

In addition, in the SSON compound, broadening of the emission peak at 540 nm and a large red transition at 610 nm can provide a broadened red spectrum. In general LED lighting elements, it is most effective when the emission wavelength of the red light-emitting phosphor is from 600 nm to 630 nm in order to improve the color rendering index of white light. According to the embodiment of the present invention, since the central light emission wavelength is 610 nm and is broadened, the color rendering property can be ensured with excellent color purity.

It is believed that these features of the present invention are caused by the strong electron cloud spreading effect of the covalent bonds caused by the incorporation of nitrogen into the crystal and the crystal field splitting. However, since the oxide-based SSO compound according to the comparative example is present in the yellow visible ray region of 600 nm or less, the emission intensity of the SSON compound at 600 nm or more, compared with the SSON compound according to the embodiment of the present invention Is not more than 40%.

The SSON according to the embodiment of the present invention is characterized in that in the case where the heat treatment temperature is 1600 占 폚 (curve T3) and 1700 占 폚 (curve T4), the near-ultraviolet region to which 320 nm and 377 nm belong and the blue visible ray In the excitation light of the region, both have the emission center wavelength at 610 nm, and a high emission intensity of 90% or more can be obtained in the 600 nm and 630 nm regions.

Therefore, the silicon oxynitride phosphor according to an embodiment of the present invention can emit red light of high purity, and by using the phosphor, it is possible to provide a white light illuminating device having improved color rendering and low color temperature. In addition, since the phosphor according to the embodiment of the present invention has a high light emission intensity, there is an advantage that brightness can be improved as well as color purity.

4 is a graph showing the ratio of the emission intensity at 477 nm and the emission intensity at 610 nm (R _em ) of the SSON compound according to the heat treatment temperature changes when the excitation wavelengths are 320 nm and 377 nm, respectively.

Referring to FIG. 4, the ratio of the emission intensity at 610 nm to the emission intensity at 477 nm (for example, 1,400 ° C, 1,500 ° C, 1,600 ° C, and 1,700 ° C) I ₆₁₀ / I ₄₇₇ ) gradually increases. SSON compounds annealed at 1,500 ° C to 1,800 ° C including 1,600 ° C and 1,700 ° C showed a R _em of greater than 1. In particular, when the excitation wavelength λ _ex was 377 nm, the emission of 610 nm was higher than that of 477 nm More dominant.

Also, although not shown in FIG. 4, in the case of excitation by light having a wavelength of 466 nm, only a single emission band was obtained in all the samples. That is, in case of the SSO compound, an emission peak occurs only at 540 nm. In the case of the SSON compound according to the embodiment of the present invention, the SSON compound can be applied as a red phosphor of a white LED using a blue light emitting chip since an emission peak appears only at 610 nn and a PLE spectrum is widely covered up to 500 nm.

5 is a graph showing the X-ray diffraction patterns of samples obtained at a heat treatment temperature of 1,700 DEG C of the SSON compound (curve S1), SMSON compound (curve S2), SCSON compound (curve S3), and SBSON compound (curve S4) according to various embodiments of the present invention. A graph showing the results of diffraction analysis. By reference, X-ray diffraction analysis of the JCPDS card _{β-Sr 2 SiO 4 (#} 38-0271) and _{α'-Sr 2 SiO 4 (#} 39-1256) on is also shown.

Referring to FIG. 5, the SSON compound (curve S1) has the same pure beta phase as the SSON compound described above. A further explanation for this can be found in FIG. However, as the other metal element M is doped, a phase change gradually occurs from a phase of? Phase?? +? Phase of a phase of? 'To a phase of?'. This depends on the ion size of the metal element M to be doped as shown in Table 2. Table 2 shows various embodiments in accordance with Example _{(Sr 1 .6 M 0 .4)} Si according to the present invention _{(O 1 - x N x)} 4: Eu 2 + doped metal ion radius and hence the emission spectrum of the ion of the compound Lt; / RTI &gt;

M Ion radius
(nm, CN = 9/10) The wavelength of the A- / B-band at each λ _ex 320 nm 337 nm 466 nm ** Phase Mg 0.089 (CN = 8) 478 ^* 477/530 604 β + α Ca 0.118 / 0.123 498/607 503/603 612 α ' Sr 0.131 / 0.136 477/606 477/602 610 beta Ba 0.147 / 0.152 492/596 502/596 607 α '

* Denotes the A-band, and ** denotes the B-band.

The size of the Mg ^{2 +} ion has a coordination number of 9 and 10 in Table 2 was described instead of the ion radius of the coordination number of 8 Mg ^{2 +} (0.089 nm) to obtain the impossible. Compared with the Ca ^{2 +} ion (ionic radius 0.112 nm) having a coordination number of 8, the ionic radius of the coordination number 9 and Ba ^{2 +} of 10 is expected to be much smaller than the ionic radius of Ca ^{2 +} . The size of the ion radius satisfies the relationship Mg <Ca <Ba.

When the metal ions are doped into the SSON compound of the? phase, the? 'phase begins to coexist with the? phase (for example, the SMSON compound), and then the? phase disappears almost (for example, it is the SCSON compound). Ultimately, for example, in the SBSON compound powder, only a pure? 'Phase is obtained. From this, it can be seen that the M ion substituted in the SSON compound prevents the transition of the α 'phase, which is a high temperature phase, to the β phase (low temperature phase) by quenching the α' phase even at room temperature. The ratio (M / Sr) of Sr to the metal M can be controlled according to the process conditions to be produced, and can be controlled by the presence or absence of the flux, the temperature and the process time, and the present invention is not limited thereto.

In one embodiment, the SMSON compound (curve S2) has a diffraction pattern almost identical to that of β-Sr ₂ SiO ₄ (# 38-0271) and α'-Sr ₂ SiO ₄ (# 39-1256) . However, it has the same diffraction pattern as that of α'-Sr ₂ SiO ₄ (# 39-1256) in the case of the SCSON compound (curve S3) and SBSON (curve S4). In the case of the SSON compound (curve S1) is has a substantially the same diffraction pattern and the _{β-Sr 2 SiO 4 (#} 38-0271). Thus, embodiments according to the second curve S2 is a silicate-based phosphor of _{β-Sr 2 SiO 4 (#} 38-0271) and _{α'-Sr 2 SiO 4 (#} 39-1256) is seen having a two-phase mixture number and, in the case of the curve S3, S4 may be predicted to have the same crystal structure and _{α'-Sr 2 SiO 4 (#} 39-1256).

The reason why each has different crystal structure is because of the size of the ion. That is, as the ion size increases (Mg <Ca <Ba), the crystal phase of β-SSON gradually disappears, and finally, only the α'-phase remains.

6 is a graph showing the relationship between the photoluminescence (SEM) of the SSON compound (curve a), the SMSON compound (curve b), the SCSON compound (curve c), and the SBSON compound excitation (PLE) spectrum. The composition of _{(Sr 1 .6 M 0 .4)} Si (O 1 - x N x) 4: Eu ^{2 +} a.

These excitation spectra were measured in the wavelength range between 200 nm and 600 nm, which is the visible light region from the ultraviolet region. All of these compounds have similar shapes and peak positions. However, the excitation intensity is increased in the order of the SMSON compound <SCSON compound <SBSON compound <SSON compound.

FIGS. 7A to 7C are emission spectra of SSON compounds, SCSON compounds, and SBSON compounds according to an embodiment of the present invention excited by excitation light sources having wavelengths of 320 nm, 377 nm and 466 nm, respectively.

Referring to FIGS. 7A to 7C, when excited by an excitation light source having a wavelength of 320 nm and 377 nm, the SSON compound, the SCSON compound and the SBSON compound according to the embodiment of the present invention are blue-green (referred to as A-band) And a red (B-band) region. However, when irradiated by an excitation light source with a wavelength of 466 nm, it exhibits only red luminescence characteristics. In addition, SSON compounds, SCSON compounds and SBSON compounds vary in wavelength of the main emission peak depending on the ion radius of M2 +.

Unlike other embodiments, the SMSON compound (curve b) has only one asymmetric band near 478 nm when excited by a light source with a wavelength of 320 nm. However, it can be confirmed that the SSON compound has two emission bands in the vicinity of 477 nm and 530 nm when irradiated with an excitation light source having a wavelength of 377 nm. From this, the nitridation reaction is not effective in causing the red shift of luminescence by Eu (II) in the SMSON compound, so that only very weak red luminescence can be obtained at excitation at 466 nm. The reason why the nitridation reaction is not effective in the SMSON compound is considered to be that the size of the Mg ²⁺ ion is relatively small, thereby offsetting the nitriding effect.

In these graphs, it can be seen that the peak position in the B-band is blue-shifted (shifted towards smaller wavelengths). The blue shift depends on the ion size of the M ion, and is shifted to blue in the order of Ca ^{2 +} <Sr ^{2 +} <Ba ^{2 +} , followed by SCSON->SSON-> SBSON. The larger the size of the M ion is due to shifts in d since the level of the crystal field separation of Eu ^{2 +} ions is smaller, Eu ^{2 +} 5d place the lowest energy level is bigger energy.

Compounds according to embodiments of the present invention exhibit red shift from an SSON compound to a SCSON compound unlike the B band when irradiated by excitation light sources of wavelengths of 320 and 377 nm in the case of the A-band. This is because Ca ^{2 +} ions are smaller than the Sr ^{+ 2} ions. The A band despite the large Ba ^{2 +} is more than Sr ^{2 +} ions, and shows a red shift to SBSON compound from SSON compound. These characteristics can be explained by comparing the crystal field and covalent bond in the Eu (I) and Eu (II) sites of the A and B spectra according to the size of M ion.

As a result, the SSON compound, the SCSON compound, the SBSON compound and the SMSON compound exhibit a wide wavelength band at an excitation wavelength near the near ultraviolet ray, which is very advantageous for white LED illumination. That is, in the case of the SSON compound, it has a wide band from the blue region to the red region, a broad emission band from the green region to the red region in the case of the SCSON compound and the SBSON compound, and a wide emission band from the blue region to the green region in the case of the SMSON compound Because.

Further, according to the embodiment of the present invention, Mg, Ba, or Ca is partially doped instead of Sr so that the red wavelength of a broad band excited by an ultraviolet region, a near ultraviolet region or a blue region light source, It is possible to obtain a red phosphor capable of maximizing the color coordination when it is used for a white LED. In addition, the silicon oxynitride phosphor according to an embodiment of the present invention can perform position tuning of a red wavelength. Thereby, the emission peak can be controlled even under the same excitation wavelength. When the metal M is Mg, a phosphor having a wide emission band from the blue region to the green region can be obtained by exciting the near-ultraviolet LED. When the metal M is Ca or Ba, the silicon oxynitride phosphor may be excited with a near ultraviolet LED to obtain a phosphor having a wide band from a green region to a red region.

8 is a graph showing the excitation spectra of the SSON compounds having different Eu ^{2 +} concentration in accordance with an embodiment of the invention. Curve a to the curve d is a measurement result of the SSON compound each having a 0.5 mol%, 1.0 mol%, 5 mol%, and 10 mol% Eu ^{2 +} concentration.

8, and therefore this increase in the strength of the spectrum with the increase of the concentration of Eu ^{2 +} to 1.0 mol% at 0.5 mol%. However, when the concentration of Eu ^{2 +} increases to 5 mol%, the intensity of the excitation spectrum begins to decrease. When the concentration of Eu ^{2 +} is 10 mol%, the intensity of the excitation spectrum decreases sharply. In addition, the increased strength of the non-emission peak of 466 nm to the emission peak intensity of the 420 nm with increasing the concentration of Eu ^{2 +.} In a preferred embodiment, Eu ^{2 +} concentration of the SSON compound is 0.8 mol% to 3 mol% containing 1.0 mol% with the largest here strength is from more preferably, 0.8 mol% to 1.2 range in mol%, the SSON compounds can have maximum excitation strength. According to the obtained excitation spectrum, the SSON powder according to the embodiment of the present invention can be applied as a near-ultraviolet light emitting diode of about 400 nm or a red phosphor of a white light emitting diode using a blue light emitting diode near 450 nm.

Figure 9 is at an excitation wavelength of 377 nm is a graph showing the emission spectrum of the SSON compounds according to the concentration change of Eu ^{2 +.} Curve a to the curve d is a measurement result of the SSON compound each having a 0.5 mol%, 1.0 mol%, 5 mol%, and 10 mol% Eu ^{2 +} concentration.

Reference to Figure 9. If, according to the embodiment of the present invention, muscle when excited by a light of excitation wavelength 377 nm in the ultraviolet ray region, Eu ^{2 +} concentration of 1.0 mol% (curve b) one time the highest in the vicinity of 608 nm And shows the emission intensity of red. In addition, this peak moves to a longer wavelength when thus increasing the concentration of Eu ^{2 +.} Thus, in accordance with an embodiment of the present invention, by controlling the concentration of Eu ^{2 +,} as well as to obtain the red light-emitting phosphor, it is possible to obtain a fluorescent substance which can control the position of the red emission peak. SSON compounds having a concentration of 0.5 mol% and 1.0 mol% of Eu 2+ can obtain light emission intensity in a wide range from a blue region to a green region in addition to a red peak having a wide half width. Therefore, the SSON compound containing 0.4 mol% to 1.2 mol% of Eu ^{2 +} containing 0.5 mol% and 1.0 mol% is very advantageous in terms of color interconnection when applied to a white light emitting diode using a near ultraviolet light emitting diode Respectively.

Figure 10 is an excitation wavelength of 466 nm from a graph showing the emission spectrum of the SSON compounds according to the concentration change of Eu ^{2 +.} Curve a to the curve d is a measurement result of the SSON compound each having a 0.5 mol%, 1.0 mol%, 5 mol%, and 10 mol% Eu ^{2 +} concentration.

Referring to Figure 10, when excited by 466 nm belongs to the blue visible region, SSON compound Eu ^{2 +} concentration represents the emission intensity of the red color high in the vicinity of 613 nm when 1.0 mol%. As the concentration of Eu ²⁺ increases, the peak shifts toward the longer wavelength side. For example, an SSON compound (curve d) in which Eu ^{2 +} is 10 mol% shows red emission at about 635 nm. According to an embodiment of the invention, it is possible to obtain a red light emission peak having a wide half-value width by adjusting the concentration of Eu ^{2 +,} it is possible to control the position of the red emission peak. therefore. The SSON compound according to an embodiment of the present invention can be used as a red phosphor of a white light emitting diode using a blue light emitting diode and can contribute to improvement of color correlation of a white light emitting diode due to a large half width of a peak.

11 is a graph showing a change in red light emission intensity with temperature change of an SSON compound according to an embodiment of the present invention.

Referring to FIG. 11, according to an embodiment of the present invention, when excited at 466 nm, which is a blue visible light region, the emission intensity gradually decreases as the temperature increases in comparison with the initial light emission intensity of the SSON compound. The SSON compound maintains a strength of about 90% of the initial light emission intensity at about 150 캜. Therefore, according to the embodiment of the present invention, Sr ₂ Si (O _{1 - x} N _x ) ₄ : Eu ^{2 +} powder is suitable as a red phosphor of a high output white light emitting diode.

Although the embodiments disclosed with reference to Figs. 8-11 relate to SSON compounds, it is expected that similar properties will also appear in SMSON compounds, SCSON compounds, or SBSON compounds in which some Sr atoms are replaced with Mg, Ca, Ba and combinations thereof . These compounds are almost unaffected by substitution by Mg, Ca, or Ba in other luminance characteristics at temperature, and have similar properties to SSON compounds.

12 is a cross-sectional view schematically showing a capsule illumination device 100 which is an optical device according to an embodiment of the present invention.

Referring to FIG. 12, the illumination device 100 includes a light source 10 that emits light and a fluorescent layer 20 that is disposed on the light path of the light source 10 and is excited by light to emit light. The light source 10 may be a semiconductor diode capable of emitting light in the recombination process occurring at the PN junction of the semiconductor. The semiconductor diode may be a UV light emitting diode capable of emitting light in the near ultraviolet region or a blue light emitting diode capable of emitting light in the blue visible light region. The phosphor layer 20 may include the red light emitting phosphor according to the embodiment of the present invention described above. The red light-emitting fluorescent material may be classified and applied so as to have a predetermined particle size distribution in the fluorescent layer 20.

The illumination device 100 may further include leads 11 and 12 for supplying electric power to the light source 10 and wires 13 electrically connecting the leads 12 and the light source 10. The light source 10, the leads 11 and 12 and the wire 13 can be sealed in a shell form by a suitable sealing material 30 such as a translucent resin, rubber and glass.

The bullet-type illumination device 100 shown in Fig. 12 is illustrative, and the present invention is not limited thereto. For example, the illumination device may be provided in a known chip type in which an illumination device is formed on a substrate having a recess portion whose top surface is opened. Alternatively, it is also possible to dispose a light source and a fluorescent layer apart from each other, and to transmit the light emitted from the fluorescent layer to a reflector. As another example, it is possible to arrange a fluorescent layer on the sealing material and further seal the fluorescent layer.

The illumination device 100 may be, for example, a white diode lamp. The white light can mix white light with a part of the emitted light from the light source 10 and the wavelength-converted light emitted by the red light-emitting phosphor excited in the fluorescent layer 20. Alternatively, the green light emitting phosphor may be further included in the fluorescent layer 20 together with the red light emitting fluorescent material. In order to realize white light, the light source 10 may be a blue light emitting diode. The blue light emitting diode may be, for example, an InGaN-based diode.

As another constitution for realizing the white light, a UV light emitting diode capable of emitting excitation light in a near ultraviolet ray region can be applied. In this case, not only a red phosphor but also a luminescent phosphor of a different color, for example, a green phosphor and a blue phosphor may be mixed in a predetermined ratio as a visible light emitter.

The illumination device 100 described above can be used as an illumination device or a display device by itself. Alternatively, the illumination device 100 may be applied to a back light unit of a display device such as a liquid crystal display device, and the present invention is not limited thereto.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be clear to those who have knowledge of.

Claims (21)

A silicon oxynitride phosphor comprising a compound represented by the following formula (1) that is irradiated by an excitation light source and emits light:
[Chemical Formula 1]
Sr _{2 - z} Si (O _{1 - x} N _x ) ₄ : zEu ^{2 +}
0 < x < 1 and 0 < z &lt; The method according to claim 1,
Wherein the silicon oxynitride phosphor is a red light-emitting phosphor. 3. The method of claim 2,
Wherein the emission peak of the red light-emitting fluorescent substance includes a main emission peak of 610 nm. The method of claim 3,
Wherein the emission peak of the red light-emitting fluorescent substance further comprises an emission peak of 477 nm. The method according to claim 1,
Wherein the excitation light source comprises ultraviolet light in the range of 300 nm to 330 nm, near ultraviolet light in the range of 370 nm to 410 nm, and blue visible light in the range of 450 nm to 470 nm. The method according to claim 1,
Wherein the silicon oxynitride phosphor has a crystal structure of? -SR ₂ SiO ₄ . The method according to claim 1,
And Z is 0.016? Z? 0.06. A silicon oxynitride phosphor containing a compound represented by the following formula (2), which is irradiated by an excitation light source and emits light.
(2)
Sr _{2 - y - z} M _y Si (O _{1 - x} N _x ) ₄ : zEu ^{2 +}
Wherein M is any one of Ca, Ba and Mg, or a combination thereof,
0 <x <1, 0 <y <2, 0 <z? 0.4, and 0 <y + z <2. 9. The method of claim 8,
Wherein the silicon oxynitride phosphor is a red light-emitting phosphor. 9. The method of claim 8,
Wherein the silicon oxynitride phosphor has a light-emitting band of a blue-green band and a band of a red color at the same time. 9. The method of claim 8,
Wherein the excitation light source comprises ultraviolet light in the range of 300 nm to 330 nm, near ultraviolet light in the range of 370 nm to 410 nm, and blue visible light in the range of 450 nm to 470 nm. 9. The method of claim 8,
Wherein the silicon oxynitride phosphor has a crystal structure of? '- Sr ₂ SiO ₄ . 9. The method of claim 8,
And Z is 0.016? Z? 0.06. SrCO _3, comprising: mixing a precursor composition having the formula Si ₃ N ₄ and Eu ₂ O _3; And
And heat-treating the mixed resultant to form a compound represented by the following formula (1): < EMI ID =
[Chemical Formula 1]
Sr _{2 - z} Si (O _{1 - x} N _x ) ₄ : zEu ^{2 +}
0 < x < 1 and 0 &lt; z &lt; 15. The method of claim 14,
Wherein the heat treatment is performed in a nitrogen atmosphere. 15. The method of claim 14,
Wherein the heat treatment is performed at 1,650 ° C to 1,800 ° C. Oxides, nitrides, carbonates, hydroxides or chlorides of precursor compositions having the formula SrCO ₃ , Si ₃ N ₄ and Eu ₂ O ₃ and metal M; And
And heat-treating the resultant mixture to form a compound represented by the following formula (2): < EMI ID =
(2)
Sr _{2 - y - z} M _y Si (O _{1 - x} N _x ) ₄ : zEu ^{2 +}
Wherein M is any one of Ca, Ba and Mg, or a combination thereof,
0 <x <1, 0 <y <2, 0 <z? 0.4, and 0 <y + z <2. 18. The method of claim 17,
Wherein the heat treatment is performed in a nitrogen atmosphere. 18. The method of claim 17,
Wherein the heat treatment is performed at 1,650 ° C to 1,800 ° C. An excitation light source that emits light belonging to at least one of a near-ultraviolet region, an ultraviolet region, and a blue region, and an excitation light source that is disposed on an optical path of the excitation light source and is illuminated by the light, And the silicon oxynitride phosphor described in item (1). 21. The method of claim 20,
Wherein the optical device is any one of a light emitting device, a lighting device, and a display device.

Images