JP4459941B2 - Phosphor and method for producing the same, and phosphor-containing composition, light emitting device, image display device, and illumination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel phosphor excellent in temperature characteristics, its manufacturing method, a phosphor-containing composition and a light-emitting device using the same, and an image display device and an illuminating device using the light-emitting device. <P>SOLUTION: The phosphor comprises a crystal phase having a chemical composition of the formula: Ce<SB>x</SB>M<SP>III</SP><SB>3-x</SB>M<SP>IV</SP><SB>y</SB>X<SP>-III</SP><SB>z</SB>(wherein M<SP>III</SP>represents elements that occupy the trivalent site together with Ce in the crystal structure, provided that trivalent metal elements account for &ge;90 mol% of such the elements and that La, Lu, Y and Gd totally account for &ge;90 mol% of the trivalent metal elements; M<SP>IV</SP>represents elements that occupy the tetravalent site in the crystal structure, provided that tetravelent metal elements account for &ge;90 mol% of such the elements and that Si and Ge totally account for &ge;90 mol% of the tetravelent metal elements; X<SP>-III</SP>represents elements that occupy the negative trivalent site in the crystal structure, provided that nitrogen accounts for &ge;85 mol% of such the elements; and x, y and z represent numbers satisfying the relations: 0.001&le;x&le;1, 5.4&le;y&le;6.6 and 9.9&le;z&le;12.1, respectively) and has an emission peak within a wavelength range of 480-650 nm. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a phosphor and a method for producing the same, a phosphor-containing composition and a light emitting device using the phosphor, and an image display device and an illumination device using the light emitting device. More specifically, the present invention relates to a phosphor excellent in temperature characteristics and a method for producing the same, a phosphor-containing composition and a light emitting device using the phosphor, and an image display device and an illumination device using the light emitting device.

The phosphor emits fluorescence of a predetermined color by absorbing excitation light, and is used in a light emitting device or the like. Of these, Y ₃ Al ₅ O ₁₂ : Ce (hereinafter referred to as “YAG” where appropriate) has been widely used as a phosphor that emits yellow fluorescence (yellow phosphor).
On the other hand, as described in Patent Document 1, La-based phosphors such as La ₃ Si ₈ N ₁₁ O ₄ are also known. These known La-based nitride phosphors are all phosphors emitting blue fluorescence (blue phosphors).
Further, Patent Documents 2 and ₃ describe phosphors having a composition of La ₃ Si ₆ N ₁₁ : Ce.

JP 2005-112922 A JP 2003-206481 A US Pat. No. 6,670,748 B2

  A light-emitting device using a phosphor is usually provided with a light source for emitting excitation light. However, many of these light sources generate heat during light emission. For this reason, when the light emitting device is used, the temperature of the phosphor may increase due to heat generated by the light source. In particular, since a brighter light emitting device has been demanded in recent years, a high-output light source such as a power LED may be used as a light source. The degree of temperature also increases.

  However, since conventional phosphors such as YAG have insufficient temperature characteristics, the light emission intensity is often lower in a high temperature environment than in a normal temperature environment. Therefore, the brightness of the conventional light emitting device may be reduced by the above temperature increase. In addition, since the balance of light components emitted from the light emitting device is easily changed due to a decrease in the emission intensity of the phosphor, it is difficult to change the color of the light emitted from the light emitting device to a desired color.

Patent Documents 2 and ₃ describe that the emission region of the phosphor La ₃ Si ₆ N ₁₁ : Ce is 435 nm to 452 nm (blue). However, according to studies by the present inventors, the phosphor does not emit blue light.

As described above, the development of a phosphor excellent in temperature characteristics has not yet been satisfactory, and further improvement has been demanded.
The present invention was devised in view of the above-mentioned problems. A novel phosphor excellent in temperature characteristics and a method for producing the same, a phosphor-containing composition and a light-emitting device using the phosphor, and a light-emitting device are disclosed. It is an object of the present invention to provide an image display device and a lighting device used.

  As a result of intensive studies to solve the above problems, the present inventors have found that a phosphor having a specific composition range has favorable temperature characteristics and is suitable as a phosphor that emits yellow light. In addition, the present inventors have found that this phosphor exhibits very excellent characteristics as a light source and can be suitably used for applications such as a light-emitting device, thereby completing the present invention.

That is, the gist of the present invention includes a crystal phase having a chemical composition represented by the following formula [1], the oxygen content in the phosphor is 1.53% by weight or less, and a wavelength of 480 nm or more and 650 nm or less. It exists in the fluorescent substance characterized by having a luminescence peak in the range (Claim 1).
^{_{Ce x M III 3-x M}} IV y X -III z [1]
(In the formula [1], M ^III is an element that enters a trivalent site together with Ce in the crystal structure of the formula [1] , and 90 mol% or more is occupied by a trivalent metal element, and includes La 90 mol% or more in the trivalent metal element, M ^IV is formula a element entering the tetravalent sites in the crystal structure of [1], 9 0 mol% or more tetravalent The tetravalent metal element contains 90 mol% or more of Si, and X- ^III is an element that enters a -3 valent site in the crystal structure of the formula [1]. Te, and nitrogen represents an element represents at least 85 mol%, x represents a number satisfying 0.001 ≦ x ≦ 0.4, y satisfies the 5. 7 ≦ y ≦ 6. 3 And z represents a number satisfying 10.5 ≦ z ≦ 11.6 .)

At this time, it is preferable that the phosphor emits yellow light.
Furthermore, the phosphor preferably has two or more excitation peaks in a wavelength range of 300 nm or more and 530 nm or less (Claim 3) .

Another gist of the present invention resides in a phosphor-containing composition comprising the phosphor and a liquid medium (claim 4 ).

Still another subject matter of the present invention includes a first light emitter and a second light emitter that emits visible light by irradiation of light from the first light emitter, and the second light emitter comprises the above-mentioned characterized in that it contains phosphor at least one consists in a light-emitting device (claim 5).

Still another subject matter of the present invention lies in an image display device comprising the light emitting device as a light source (Claim 6 ).

Still another subject matter of the present invention lies in an illuminating device comprising the light emitting device as a light source (Claim 7 ).

  ADVANTAGE OF THE INVENTION According to this invention, the novel fluorescent substance excellent in the temperature characteristic and its manufacturing method can be provided. Moreover, a high-performance light-emitting device can be obtained by using a phosphor resin composition containing this phosphor. Moreover, this light-emitting device is used suitably for the use of an image display apparatus or an illuminating device.

Hereinafter, the present invention will be described with reference to embodiments and examples, but the present invention is not limited to the following embodiments and examples, and may be arbitrarily modified without departing from the gist of the present invention. Can be implemented.
In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
Furthermore, the relationship between color names and chromaticity coordinates in this specification is all based on the JIS standard (JISZ8110).

Further, in the phosphor composition formula in this specification, each composition formula is delimited by a punctuation mark (,). In addition, when a plurality of elements are listed separated by commas (,), one or two or more of the listed elements may be included in any combination and composition. For example, the composition formula “(Ba, Sr, Ca) Al ₂ O ₄ : Eu” has “BaAl ₂ O ₄ : Eu”, “SrAl ₂ O ₄ : Eu”, and “CaAl ₂ O ₄ : Eu”. If: the _{"Ba 1-x Sr x Al 2} O 4 Eu ": the _{"Ba 1-x Ca x Al 2} O 4 Eu ": a _{"Sr 1-x Ca x Al 2} O 4 Eu " _{"Ba 1-x-y Sr x} Ca y Al 2 O 4: Eu " and all assumed to generically indicated (in the above formula, 0 <x <1,0 <y <1,0 <X + y <1).

[I. Phosphor of the present invention]
[I-1. Composition of crystal phase]
The phosphor of the present invention contains a crystal phase having a chemical composition represented by the following formula [1].
^{_{Ce x M III 3-x M}} IV y X -III z [1]
(In the above formula [1],
M ^III is an element that enters a trivalent site together with Ce in the crystal structure of the formula [1], and 90 mol% or more is occupied by a trivalent metal element. In which the total of La, Lu, Y and Gd represents 90 mol% or more,
M ^IV is an element that enters a tetravalent site in the crystal structure of the formula [1], and 90 mol% or more is occupied by a tetravalent metal element. Among the tetravalent metal elements, Si is Si. And an element in which the total of Ge occupies 90 mol% or more,
X- ^III represents an element that enters a -3 valent site in the crystal structure of the formula [1], and nitrogen represents an element that occupies 85 mol% or more;
x represents a number satisfying 0.001 ≦ x ≦ 1,
y represents a number satisfying 5.4 ≦ y ≦ 6.6,
z represents a number satisfying 9.9 ≦ z ≦ 12.1. )

Hereinafter, the formula [1] will be described in detail.
In the formula [1], M ^III represents an element that enters a trivalent site together with Ce in the crystal structure of the formula [1]. Examples include trivalent metal elements such as La, Lu, Y, Gd, Pr, Nd, Sm, Eu, Tb, Ho, Er, Yb, Sc, Ga, In, Al, Ga, and Bi. Can be mentioned. M ^III may be used alone or in combination of two or more.

However, in the formula [1] is usually 90 mol% or more of M ^III, preferably 92 mol% or more, and more preferably at least 95 mol%, is occupied by a trivalent metal element. In addition, the upper limit of this range is theoretically 100 mol% or less, and it is most preferable that it is 100 mol%. If the proportion of the trivalent metal element in M ^III becomes too small, the emission intensity may be reduced.

In addition, the trivalent metal element (that is, the trivalent metal element occupying 90 mol% or more of M ^III ) is the total of La, Lu, Y, and Gd in the entire trivalent metal element. The ratio is usually 90 mol% or more, preferably 92 mol% or more, more preferably 95 mol% or more. In addition, the upper limit of this range is theoretically 100 mol% or less, and it is most preferable that it is 100 mol%. If the total ratio of La, Lu, Y, and Gd in the entire trivalent metal element is too small, the emission intensity may be reduced.

In the formula [1], M ^IV represents an element that enters a tetravalent site in the crystal structure of the formula [1]. Examples thereof include Si, Ge, Sn, Ti, Zr, Hf and the like. Further, M ^IV may be used alone or may be used in combination of two or more.

However, in the formula [1] is usually 90 mol% or more of M ^IV, preferably 92 mol% or more, and more preferably at least 95 mol%, is occupied by tetravalent metal elements. In addition, the upper limit of this range is theoretically 100 mol% or less, and it is most preferable that it is 100 mol%. When the ratio of the tetravalent metal elements occupying the M ^IV is too small, the emission intensity may be lowered.

Moreover, the tetravalent metal element (i.e., tetravalent metal element accounts for at least 90 mol% of M ^IV) occupies in the entire tetravalent metal elements, the total ratio of Si and Ge is usually It is 90 mol% or more, preferably 92 mol% or more, more preferably 95 mol% or more. In addition, the upper limit of this range is theoretically 100 mol% or less, and it is most preferable that it is 100 mol%. If the total ratio of Si and Ge in the total tetravalent metal element is too small, the emission intensity may be reduced.

In the formula [1], X- ^III represents an element that enters a -3valent site in the crystal structure of the formula [1]. For example, -3 valent elements such as N; -2 valent elements such as O and S; -1 valent elements such as F and Cl; X- ^III may be used ^alone or in combination of two or more. Here, the X ^-III, OH ^- is intended to include those two elements, such as bound.

However, in the formula [1], N is usually occupied by 85 mol% or more, preferably 92 mol% or more, more preferably 95 mol% or more of X- ^III . In addition, although there is no restriction | limiting in the upper limit of this range, In theory, it is 100 mol% or less, and it is most preferable that it is 100 mol%. However, in practice, since the oxygen in the raw material are contained, oxygen is mixed into the phosphor crystal phases to be synthesized, the ratio of N to total X ^-III is correspondingly reduced from 100%, X ^{- In} many cases, the proportion of N in ^III is 99 mol% or less. If the proportion of N in X- ^III is too small, the emission intensity tends to decrease.
In addition, when the ratio of N to X- ^III is less than 100 mol%, it is preferable that it is O as elements other than N contained as X- ^III .

  In the formula [1], x is a number representing the number of moles of Ce, and is usually 0.001 or more, preferably 0.005 or more, more preferably 0.01 or more, still more preferably 0.02 or more, Usually, it is 1 or less, preferably 0.7 or less, more preferably 0.4 or less, and still more preferably 0.3 or less. If x is too small, the excitation light emission by Ce is not sufficient, and the light emission intensity may be lowered. If x is too large, concentration quenching may occur and the light emission intensity may be lowered.

In the formula [1], y is a number representing the number of moles of M ^IV is usually 5.4 or more, preferably 5.7 or more and usually 6.6 or less, preferably 6.3 or less, A value close to 6 is preferred. When y is too small or too large, lattice defects are caused and the light emission intensity is often lowered.

In the formula [1], z is a number representing the number of moles of X- ^III , usually 9.9 or more, preferably 10.5 or more, more preferably 10.7 or more, and usually 12.1 or less. Preferably it is 11.6 or less, More preferably, it is 11.3 or less, and the one close | similar to 11 is preferable. If z is too small or too large, lattice defects are often caused and the emission intensity is often lowered.

Specific examples of preferred ones of the chemical composition of the formula [1] are given below, but the composition of the phosphor of the present invention is not limited to the following examples.
That is, as a preferable example of the chemical composition of the formula [1], as an example in which oxygen is not mixed, Ce _0.1 La _2.9 Si ₆ N ₁₁ , Ce _0.02 La _2.98 Si ₆ N _{11 and the} like, in which slight oxygen is mixed, Ce _0.1 La _2.89 Si ₆ N _10.97 O _0.03 , Ce _0.1 La _2.7 Si ₆ N _10.4 O _0.6 etc. are mentioned.

  Moreover, if the phosphor of the present invention contains at least a part of the crystal phase having the chemical composition of the formula [1] described above, the entire phosphor has the chemical composition of the formula [1]. You do not need to have it. The phosphor of the present invention may contain a crystal phase different from the crystal phase having the chemical composition of the formula [1], and the phosphor as a whole may have two or more kinds of crystal phases. Under the present circumstances, about parts other than the crystal phase which has a chemical composition of Formula [1], unless the effect of this invention is impaired remarkably, there is no restriction | limiting and it is arbitrary. However, in order to obtain the advantages of the present invention remarkably, it is most preferable that the entire phosphor is composed of a crystal phase having the chemical composition of the formula [1] described above.

[I-2. Characteristics of phosphor
[I-2-1. Characteristics of fluorescent color]
The phosphor of the present invention usually emits yellow light. That is, the phosphor of the present invention is usually a yellow phosphor.
When the phosphor of the present invention emits yellow light, the chromaticity coordinates of the fluorescence are usually (x, y) = (0.393, 0.464), (0.513, 0.464), (0 .393, 0.584) and (0.513, 0.584), preferably (x, y) = (0.418, 0.489), (0.488, 0.489), (0.418, 0.559), and coordinates within the region surrounded by (0.488, 0.559).
The fluorescence chromaticity coordinates can be calculated from an emission spectrum described later.

[I-2-2. Characteristics of emission spectrum]
The fluorescence spectrum (emission spectrum) emitted by the phosphor of the present invention is not particularly limited. However, in view of the use as a yellow phosphor, the emission spectrum has the following characteristics when excited with light having a wavelength of 455 nm. It is preferable.

  That is, the emission peak wavelength of the phosphor of the present invention is in the wavelength range of 480 nm or more and 650 nm or less. Since Ce as an activator has two types of ground states, the phosphor of the present invention often has two emission peaks according to the difference in energy level between the two types of ground states. In this case, the emission peak on the long wavelength side has an emission peak in a wavelength range of usually 550 nm or more, preferably 570 nm or more, and usually 650 nm or less, preferably 620 nm or less. On the other hand, the peak on the short wavelength side has an emission peak in a wavelength range of usually 480 nm or more, preferably 510 nm or more, and usually 580 nm or less, preferably 570 nm or less. If the wavelength of the emission peak is too short or too long, an appropriate complementary color relationship cannot be obtained in combination with the first light emitter described later, and it may be difficult to obtain good white light.

  Further, the light emitting region of the phosphor of the present invention will be described. In the emission spectrum, the wavelength region where the height of the highest emission peak is half or more is preferably wider, and the upper limit is usually 520 nm or more, preferably 530 nm or more, and the lower limit is usually 620 nm or less, preferably Is 600 nm or less. Since the light emitting region is large in this way, when the phosphor of the present invention is used, the color rendering properties of the light emitting device and the like can be improved.

In addition, the phosphor of the present invention has a full width at half maximum of emission peak (hereinafter referred to as “FWHM” as appropriate) of usually 110 nm or more, preferably 120 nm or more, more preferably 130 nm or more. Thus, when the half value width is wide, when the phosphor of the present invention is combined with a blue LED or the like, the color rendering properties of the light emitting device or the like can be improved. In addition, although there is no restriction | limiting in the upper limit of the half value width of a light emission peak, Usually, it is 280 nm or less.
In addition, the phosphor of the present invention often has a plurality of emission peaks to be precise, and in the case of having a plurality of emission peaks, the width of the wavelength region having an intensity of half or more of the intensity of the highest intensity peak. Is the full width at half maximum.

  The measurement of the emission spectrum of the phosphor of the present invention and the calculation of the emission region, emission peak wavelength, and peak half-value width can be performed at room temperature using an apparatus such as a fluorescence measuring apparatus manufactured by JASCO Corporation.

[I-2-3. Characteristics related to excitation spectrum]
The excitation light spectrum (excitation spectrum) of the phosphor of the present invention is not limited, and the phosphor of the present invention can be excited by light in the blue region or light in the near ultraviolet region.
Among them, the excitation light suitable for the phosphor of the present invention is usually emitted in a wavelength region of 420 nm or more, preferably 430 nm or more, more preferably 435 nm or more, and usually 490 nm or less, preferably 480 nm or less, more preferably 470 nm or less. It has a peak (hereinafter, the emission peak of excitation light is referred to as “excitation peak” as appropriate). Even if the excitation peak is too short or too long, the intensity excited by the first illuminant described later decreases.

In particular, the excitation spectrum of the present invention preferably has two or more excitation peaks, and more preferably has two or more excitation peaks in a wavelength range of usually 300 nm to 530 nm, more preferably 360 nm to 410 nm. It is more preferable to have excitation peaks both in the following wavelength range and in the wavelength range of 430 nm to 475 nm. This is because it can be excited by light in the blue region or light in the near ultraviolet region. In particular, the phosphor of the present invention has an excitation peak in the light emitting region of a zinc oxide LED that emits light in the near ultraviolet region, and is therefore suitable as a phosphor to be combined with a near future LED.
The ratio of but this time, no limit to the size of each excitation peak, the highest excitation peak (i.e., most intense large excitation peak) and height I _A of the high excitation peak in the second to the height I _B I _A / I _B is usually 0.5 or more, preferably 0.6 or more, more preferably 0.64 or more. If the ratio I _A / I _B is too small or too large, it may be difficult to obtain the effect that excitation is possible with both light in the blue region and light in the near ultraviolet region. The upper limit is usually 2 or less.

  The measurement of the excitation spectrum and the calculation of the excitation peak can be performed using a device such as a fluorescence measuring device manufactured by JASCO Corporation at room temperature, for example.

[I-2-4. Characteristics related to oxygen content]
The oxygen content of the phosphor of the present invention is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1.8% by weight or less, preferably 1.3% by weight or less, more preferably 1.2% by weight. It is as follows. If the oxygen content of the phosphor of the present invention is too high, the emission intensity may be reduced. Furthermore, the crystal phase that emits blue light described in Japanese Patent Application Laid-Open No. 2003-206481 (Patent Document 4) and US Pat. No. 6,670,748B2 (Patent Document 5) (according to the study by the present inventors, La ₃ Si ₆ N ₁₁ : Ce, but not LaSi ₃ N ₅ : Ce), and yellow light emission tends not to be obtained. Note that the lower limit of the oxygen content is such that even if the oxygen is not contained, oxygen is mixed into the synthesized phosphor crystal phase due to the oxygen contained in the raw material, so that the oxygen content is 0. Often 2% by weight or more.
The oxygen content of the phosphor of the present invention can be measured by a method in which oxygen in the phosphor is detected with infrared rays after carbonization.

[I-2-5. Weight median diameter]
The phosphor of the present invention preferably has a weight median diameter in the range of usually 0.1 μm or more, particularly 0.5 μm or more, and usually 30 μm or less, especially 20 μm or less. If the weight median diameter is too small, the luminance is lowered and the phosphor particles tend to aggregate, which is not preferable. On the other hand, when the weight median diameter is too large, there is a tendency that uneven coating or blockage of a dispenser or the like occurs, which is not preferable.
The weight median diameter of the phosphor of the present invention can be measured using a device such as a laser diffraction / scattering particle size distribution measuring device.

[I-2-6. Temperature characteristics]
The phosphor of the present invention is excellent in temperature characteristics. For example, when excited with excitation light having a wavelength of 455 nm, the emission intensity maintenance factor at a temperature of 140 ° C. with respect to the temperature of 24 ° C. (that is, the ratio of the emission intensity I _{24 at} 24 ° C. to the emission intensity I _{140 at} 140 ° C. I ₁₄₀ / I ₂₄ ) is usually 60% or more, preferably 66% or more, more preferably 72% or more. Thus, since it is excellent in temperature characteristics, the light-emitting device of the present invention is suitable for use in a light-emitting device described later.
The emission intensity maintenance rate can be measured with a plate heating type temperature characteristic evaluation apparatus.

[I-2-7. chemical resistance]
The phosphor of the present invention is usually excellent in chemical resistance. For example, the phosphor of the present invention can emit fluorescence even after the crystal phase having the chemical composition of the formula [1] is not dissolved in aqua regia having a very strong acid strength and is immersed in aqua regia. Therefore, the phosphor of the present invention can be used in various environments and is very useful industrially.

[I-3. Method for producing phosphor]
There is no restriction | limiting in the manufacturing method of the fluorescent substance of this invention, Arbitrary methods can be employ | adopted. For example, a phosphor precursor can be prepared as a raw material, the phosphor precursors can be mixed (mixing step), and the mixed phosphor precursor can be fired (firing step). Hereinafter, as an example of the method for producing the phosphor of the present invention, this production method (hereinafter, appropriately referred to as “production method according to the present invention”) will be described.

[I-3-1. Preparation of phosphor precursor]
Examples of the phosphor precursor include Ce raw material (hereinafter referred to as “Ce source” as appropriate), M ^III raw material (hereinafter referred to as “M ^III source” as appropriate), and M ^IV raw material (hereinafter referred to as appropriate). called "M ^IV source"), and, to prepare a raw material of ^{X -III} (hereinafter referred to as ^{"X -III} source").

Examples of the Ce source, M ^III source, and M ^IV source used in the production method according to the present invention include nitrides of these Ce, M ^III and M ^IV , nitrogen-containing compounds such as Si (NH) ₂ , oxidation, and the like. Products, hydroxides, carbonates, nitrates, sulfates, oxalates, carboxylates, halides and the like. What is necessary is just to select suitably from these compounds according to the kind of baking atmosphere, such as nitrogen, hydrogen containing nitrogen, ammonia, and argon.

  Specific examples of the Ce source include cerium nitride and cerium oxide.

Specific examples of the M ^III source are listed separately for each type of M ^III as follows.
That is, among the M ^III sources, examples of the La source include lanthanum nitride, lanthanum oxide, lanthanum nitrate, lanthanum hydroxide, lanthanum oxalate, and lanthanum carbonate. Of these, lanthanum nitride is preferable.
Among the M ^III sources, examples of the Lu source include lutetium nitride, lutetium oxide, lutetium nitrate, and lutetium oxalate.
Further, among the M ^III sources, examples of the Y source include yttrium nitride, yttrium oxide, yttrium nitrate, yttrium oxalate, and yttrium carbonate.
Among the M ^III sources, examples of the Gd source include gadolinium nitride, gadolinium oxide, gadolinium nitrate, gadolinium hydroxide, and gadolinium oxalate.

Specific examples of the M ^IV source are listed separately for each type of M ^IV as follows.
That is, among the M ^IV sources, examples of the Si source include Si ₃ N ₄ , SiO ₂ , H ₄ SiO ₄ , Si (NH) ₂ , and Si (OCOCH ₃ ) ₄ . Among these, Si ₃ N ₄ is preferable.
Among the M ^IV sources, examples of the Ge source include Ge ₃ N ₄ , GeNH, GeO ₂ , Ge (OH) ₄ , Ge (OCOCH ₃ ) ₄ , and GeCl ₄ . Among these, Ge ₃ N ₄ is preferable.

Specific examples of the X ^{- III} source are listed separately for each type of X- ^III as follows.
That is, among the X- ^III sources, examples of the N source include nitrides such as lanthanum nitride, silicon nitride, and cerium nitride. When ammonia, hydrogen-containing nitrogen, or the like is selected as the firing atmosphere, the firing atmosphere can be an N source.
Among the X- ^III sources, examples of the O source include oxygen contained in silicon nitride, oxygen contained in lanthanum nitride, oxygen in cerium oxide, and the like.
Further, among the X- ^III sources, examples of the S source include sulfides such as lanthanum sulfide and cerium sulfide.
Among the X- ^III sources, examples of the F source include fluorides such as lanthanum fluoride and cerium fluoride.
Further, among the X- ^III sources, examples of the Cl source include chlorides such as lanthanum chloride and cerium chloride.

Incidentally, Ce source, M ^III source, M ^IV source and X ^-III source, respectively, may be used alone, or as a combination of two or more kinds in any combination and in any ratio.
A certain phosphor precursor may also ^serve as two or more of Ce source, M ^III source, M ^IV source and X- ^III source.

[I-3-2. Mixing process]
The method of mixing the Ce source, the M ^III source, the M ^IV source, and the X- ^III source is not particularly limited, and examples thereof include the following methods (A) and (B).

(A) Dry pulverizer such as hammer mill, roll mill, ball mill, jet mill, etc., pulverization using mortar and pestle, etc., mixer such as ribbon blender, V-type blender and Henschel mixer, or mortar and pestle A dry mixing method in which phosphor precursors such as Ce source, M ^III source, M ^IV source and X- ^III source are pulverized and mixed in combination with mixing.

(B) Add a solvent or dispersion medium such as water to phosphor precursors such as Ce source, M ^III source, M ^IV source and X- ^III source, and add a pulverizer, mortar and pestle, or evaporating dish and stir bar A wet mixing method in which the mixture is mixed to form a solution or slurry and then dried by spray drying, heat drying, or natural drying.

[I-3-3. Firing step]
In the firing step, a mixture of phosphor precursors such as Ce source, M ^III source, M ^IV source and X ^{- III} source obtained by the above-mentioned mixing step is usually obtained from a material having low reactivity with each phosphor precursor. This is done by heating in a heat-resistant container such as a crucible or tray.

Although the temperature at the time of baking is arbitrary as long as the phosphor of the present invention is obtained, it is usually 1400 ° C. or higher, preferably 1600 ° C. or higher, more preferably 1700 ° C. or higher, and usually 2300 ° C. or lower, preferably 2150 ° C. or lower. Range. If the firing temperature is too low or too high, it tends to be difficult to produce the crystal phase of the present invention.
The pressure at the time of firing varies depending on the firing temperature and the like, but in normal cases, it is often performed at normal pressure from the viewpoint of simplicity. However, when the firing atmosphere is nitrogen, it is usually 3 atmospheres or more, preferably 4 atmospheres or more, more preferably 8 atmospheres or more.
The firing time varies depending on the temperature and pressure during firing, but is usually 10 minutes or longer, preferably 1 hour or longer, usually 24 hours or shorter, preferably 10 hours or shorter.

  The atmosphere during firing is not particularly limited as long as the phosphor of the present invention is obtained, but in the present invention, firing is preferably performed in an atmosphere having a low oxygen concentration. This is for suppressing the oxygen content of the obtained phosphor. The oxygen concentration at the time of firing is preferably 100 ppm or less, more preferably 50 ppm or less, and particularly preferably 20 ppm or less. Ideally, no oxygen is present at all. As specific examples of the atmosphere at the time of firing, it is desirable to change appropriately according to the type of raw material, but a mixed gas of nitrogen and hydrogen, an inert gas such as ammonia gas, argon, carbon monoxide, carbon dioxide, and the like It is possible to use a mixed gas or the like. Among these, nitrogen gas or a mixed gas of nitrogen and hydrogen is preferable.

  Further, from the viewpoint of suppressing the oxygen content of the phosphor, when handling the phosphor precursor before the firing step, each operation is preferably performed in an atmosphere having a low water content and oxygen content. Therefore, for example, from the weighing of each phosphor precursor to the filling of the phosphor precursor into a crucible or the like in the firing step, the phosphor precursor should be handled in an atmosphere with a low water content and oxygen content. Is preferred.

[I-3-4. Post-processing]
After the above-described firing step, the phosphor of the present invention can be obtained by performing treatments such as washing, drying, and classification as necessary.
In addition, when manufacturing the light-emitting device by the method to be described later using the phosphor of the present invention, it is preferable to perform a known surface treatment, for example, calcium phosphate treatment, if necessary, before use.
Further, if the portion other than the crystal phase having the chemical composition of the formula [1] is removed by aqua regia treatment or the like, the luminous efficiency of the phosphor of the present invention can be further enhanced.

[I-4. Use of phosphor]
The phosphor of the present invention can be used for any application that uses the phosphor. In particular, taking advantage of the fact that it can be excited by blue light or near-ultraviolet light, various light emitting devices (see “ It is suitable for use in the light-emitting device of the invention. In particular, when the phosphor of the present invention is a yellow phosphor, a white light emitting device can be manufactured by combining an excitation light source that emits blue light. Further, by combining this white light emitting device with a red phosphor (phosphor that emits red fluorescence), it is possible to realize a light emitting device that emits light of a light bulb color (warm white). A white light emitting device can also be manufactured by combining the phosphor of the present invention and a blue phosphor with an excitation light source that emits near-ultraviolet light.

  The emission color of the light-emitting device is not limited to white, and if necessary, by combining red phosphor, blue phosphor, green phosphor (phosphor emitting green fluorescence), other types of yellow phosphor, etc. A light emitting device that emits light of any color can be manufactured. The light-emitting device thus obtained can be used as a light-emitting portion (particularly a liquid crystal backlight) or an illumination device of an image display device.

[I-5. Phosphor-containing composition]
When the phosphor of the present invention is used for a light emitting device or the like, it is preferably used in a form dispersed in a liquid medium. The phosphor of the present invention dispersed in a liquid medium will be referred to as “the phosphor-containing composition of the present invention” as appropriate.

  The liquid medium that can be used in the phosphor-containing composition of the present invention is a liquid medium that exhibits liquid properties under the desired use conditions, and that suitably disperses the phosphor of the present invention and does not cause undesirable reactions. If there is, it is possible to select an arbitrary one according to the purpose. Examples of the liquid medium include silicone resin, epoxy resin, polyvinyl resin, polyethylene resin, polypropylene resin, and polyester resin. These liquid media may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. In addition, an organic solvent can be contained in the liquid medium.

  The amount of the liquid medium used may be appropriately adjusted according to the application, etc., but in general, the weight ratio of the liquid medium to the phosphor of the present invention is usually 3% by weight or more, preferably 5% by weight or more, Moreover, it is 30 weight% or less normally, Preferably it is the range of 15 weight% or less. When the amount of the liquid medium is too small, the amount of light emitted from the phosphor-containing composition per volume tends to decrease, and when the amount is too large, the dispersibility of the phosphor powder tends to deteriorate and color unevenness tends to occur.

In addition to the phosphor of the present invention and the liquid medium, the phosphor-containing composition of the present invention may contain other optional components depending on its use and the like. Examples of other components include a diffusing agent, a thickener, a bulking agent, and an interference agent. Specifically, silica-based fine powder such as Aerosil, alumina and the like can be mentioned. In addition, these other components may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.
In general, when the phosphor-containing composition is used for a constituent member such as a light emitting device (for example, a second light emitter to be described later), the phosphor-containing composition is cured by curing a liquid medium. Use.

[II. Light emitting device]
Next, the light emitting device of the present invention will be described. The light-emitting device of the present invention includes at least a first light-emitting body and a second light-emitting body that emits visible light when irradiated with light from the first light-emitting body.
[II-1. First luminous body]
The 1st light-emitting body in the light-emitting device of this invention light-emits the light which excites the 2nd light-emitting body mentioned later. The light emission wavelength of the first light emitter is not particularly limited as long as it overlaps with the absorption wavelength of the second light emitter described later, and a light emitter having a wide light emission wavelength region can be used. Usually, an illuminant having an emission wavelength from the near-ultraviolet region to the blue region is used, and specific values are usually 300 nm or more, preferably 330 nm or more, and usually 500 nm or less, preferably 480 nm or less. A luminescent material is used. As the first light emitter, a semiconductor light emitting element is generally used. Specifically, a light emitting diode (abbreviated as “LED” as appropriate) or a semiconductor laser diode (semiconductor laser diode as appropriate). And abbreviated as “LD”).

Among these, as the first light emitter, a GaN LED or LD using a GaN compound semiconductor is preferable. This is because GaN-based LEDs and LDs have significantly higher light emission output and external quantum efficiency than SiC-based LEDs that emit light in this region, and are extremely bright with very low power when combined with the phosphor. This is because light emission can be obtained. For example, for a current load of 20 mA, GaN-based LEDs and LDs usually have a light emission intensity 100 times or more that of SiC-based. GaN-based LEDs and LDs preferably have an Al _X Ga _Y N light emitting layer, a GaN light emitting layer, or an In _X Ga _Y N light emitting layer. Among the GaN-based LEDs, those having an In _X Ga _Y N light-emitting layer are particularly preferable because the emission intensity is very strong, and in the GaN-based LD, the multiple quantum of the In _X Ga _Y N layer and the GaN layer is preferable. A well structure is particularly preferable because the emission intensity is very strong.

  In the above, the value of X + Y is usually a value in the range of 0.8 to 1.2. In the GaN-based LED, those in which the light emitting layer is doped with Zn or Si or those without a dopant are preferable for adjusting the light emission characteristics.

A GaN-based LED has these light-emitting layer, p-layer, n-layer, electrode, and substrate as basic components, and the light-emitting layer is made of n-type and p-type Al _X Ga _Y N layers, GaN layers, or In _X Those having a hetero structure sandwiched between Ga _Y N layers and the like have high luminous efficiency, and those having a hetero structure having a quantum well structure further have high luminous efficiency and are more preferable.

[II-2. Second luminous body]
The second light emitter in the light emitting device of the present invention is a light emitter that emits visible light upon irradiation with light from the first light emitter described above, and contains the first phosphor, depending on its use and the like. The second phosphor is appropriately contained. Further, for example, the second light emitter is configured by dispersing the first and / or second phosphors in a sealing material.

[II-2-1. First phosphor]
In the light emitting device of the present invention, the second light emitter contains the above phosphor of the present invention, and contains at least one or more phosphors of the present invention as the first phosphor. In addition to the phosphor of the present invention, a phosphor that emits the same color fluorescence as the phosphor of the present invention (same color combined phosphor) may be used as the first phosphor. Since the phosphor of the present invention is usually a yellow phosphor, other types of yellow phosphor can be used together with the phosphor of the present invention as the first phosphor.

As an example of a yellow phosphor that can be used together with the phosphor of the present invention as the first phosphor, Y ₃ Al ₅ O ₁₂ : Ce, Eu-activated M _x (Si, Al) ₁₂ (O, N) ₁₆ ( M represents a metal element such as Ca, Y, etc. Here, x is the number of moles of oxygen atoms divided by the average valence of M, and the number of moles of oxygen atoms is usually greater than 0, 4 .3 or less is preferable). In addition, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and ratios.

The emission peak wavelength λ _p (nm) of the first phosphor is not limited, but when a yellow phosphor is used as the first phosphor, it is usually 500 nm or more, preferably 520 nm or more, and usually 650 nm or less. The wavelength range is preferably 630 nm or less. Even if the emission peak wavelength of the first phosphor is too short or too long, a good white color tends not to be obtained in combination with the first phosphor or the second phosphor.

  There is no limitation on the half-value width (FWHM) of the emission peak of the first phosphor, but when a yellow phosphor is used as the first phosphor, it is usually 110 nm or more, preferably 120 nm or more, and usually 280 nm or less. is there. If this half-value width is too narrow, the color rendering may deteriorate.

  The emission peak wavelength and half-value width of the first phosphor can be measured by a fluorescence measuring device equipped with a CCD or a multi-photo analyzer.

  When the phosphor of the present invention and other phosphors are used in combination as the first phosphor, the ratio of the two is arbitrary as long as the effects of the present invention are not significantly impaired. However, it is preferable that the ratio of the phosphor of the present invention is large. Specifically, the ratio of the phosphor of the present invention to the entire first phosphor is usually 40% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more. However, it is particularly preferable to use only the phosphor of the present invention as the first phosphor.

[II-2-2. Second phosphor]
The second light emitter in the light emitting device of the present invention may contain a phosphor (that is, a second phosphor) in addition to the first phosphor described above, depending on the application. The second phosphor is a phosphor having an emission wavelength different from that of the first phosphor. Usually, since these second phosphors are used to adjust the color tone of light emitted from the second light emitter, the second phosphor emits fluorescence having a color different from that of the first phosphor. Often phosphors are used. As described above, since a yellow phosphor is usually used as the first phosphor, examples of the second phosphor include phosphors other than yellow phosphors such as a red phosphor, a green phosphor, and a blue phosphor. Is used.

  When a red phosphor is used as the second phosphor, any red phosphor can be used as long as the effects of the present invention are not significantly impaired. At this time, the emission peak wavelength of the red phosphor is usually in the wavelength range of 610 nm or more, preferably 615 nm or more, more preferably 620 nm or more, and usually 660 nm or less, preferably 655 nm or less, more preferably 650 nm or less. Is preferred. When the emission peak wavelength of the red phosphor is too short or too long, it may be difficult to obtain warm white light such as a light bulb color.

  When a green phosphor is used as the second phosphor, any green phosphor can be used as long as the effects of the present invention are not significantly impaired. At this time, the emission peak wavelength of the green phosphor is usually in the wavelength range of 500 nm or more, preferably 510 nm or more, more preferably 520 nm or more, and usually 570 nm or less, preferably 560 nm or less, more preferably 550 nm or less. Is preferred.

  When a blue phosphor is used as the second phosphor, any blue phosphor can be used as long as the effects of the present invention are not significantly impaired. At this time, the emission peak wavelength of the blue phosphor is usually in the wavelength range of 430 nm or more, preferably 435 nm or more, more preferably 440 nm or more, and usually 490 nm or less, preferably 480 nm or less, more preferably 470 nm or less. Is preferred. Even if the emission peak wavelength of the blue phosphor is too short or too long, a good white color tends not to be obtained in combination with the first phosphor and the first phosphor.

  In addition, as a 2nd fluorescent substance, 1 type of fluorescent substance may be used independently, and 2 or more types of fluorescent substance may be used together by arbitrary combinations and a ratio. Further, the ratio between the first phosphor and the second phosphor is also arbitrary as long as the effects of the present invention are not significantly impaired. Therefore, the usage amount of the second phosphor, the combination and ratio of the phosphors used as the second phosphor, and the like may be arbitrarily set according to the use of the light emitting device.

  In the light emitting device of the present invention, the presence / absence and type of the second phosphor (red phosphor, blue phosphor, green phosphor, etc.) described above may be appropriately selected according to the use of the light emitting device. . For example, when the first phosphor is a yellow phosphor, when the light-emitting device of the present invention is configured as a light-emitting device that emits yellow light, only the first phosphor may be used. The use of this phosphor is usually unnecessary.

  On the other hand, in order to obtain light of a desired color, as the phosphor contained in the second phosphor, a light emitting device is appropriately combined with the first phosphor (yellow phosphor) and the second phosphor. It is also possible to configure.

Examples of preferable combinations of the first light emitter, the first phosphor, and the second phosphor in the case of constituting the light emitting device include the following combinations (i) to (iv). .
(I) A blue light emitter (blue LED or the like) is used as the first light emitter, and a yellow phosphor (such as the phosphor of the present invention) is used as the first phosphor. Thus, a light emitting device that emits pseudo white light can be configured.
(Ii) A blue phosphor (blue LED or the like) is used as the first phosphor, a yellow phosphor (such as the phosphor of the present invention) is used as the first phosphor, and red fluorescence is used as the second phosphor. Use the body. Thereby, the light-emitting device which light-emits light bulb color can be comprised.
(Iii) A near ultraviolet light emitter (near ultraviolet LED or the like) is used as the first light emitter, a yellow phosphor (such as the phosphor of the present invention) is used as the first phosphor, and the second phosphor is used. A blue phosphor is used. Thus, a light emitting device that emits pseudo white light can be configured.
(Iv) A near ultraviolet light emitter (near ultraviolet LED or the like) is used as the first light emitter, a yellow phosphor (such as the phosphor of the present invention) is used as the first phosphor, and the second phosphor is used. A red phosphor and a blue phosphor are used. Thereby, the light-emitting device which light-emits light bulb color can be comprised.

[I-2-3. Other characteristics of first and second phosphors]
The weight median diameter of the first phosphor and the second phosphor is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1 μm or more, particularly 0.5 μm or more, and usually 30 μm or less, especially 20 μm. The following range is preferable. When the weight median diameter is too small, the luminance is lowered and the phosphor particles tend to aggregate. On the other hand, when the weight median diameter is too large, there is a tendency for coating unevenness and blockage of a dispenser to occur.

[II-2-4. Sealing material]
The second light emitter is usually configured by dispersing a first phosphor and a second phosphor used as necessary in a sealing material.
If the example of a sealing material is given, resin materials, such as a thermoplastic resin, a thermosetting resin, and a photocurable resin, will be mentioned. Specific examples include methacrylic resins such as methyl polymethacrylate; styrene resins such as polystyrene and styrene-acrylonitrile copolymers; polycarbonate resins; polyester resins; phenoxy resins; butyral resins; polyvinyl alcohols; Cellulose resins such as cellulose acetate butyrate; epoxy resins; phenol resins; silicone resins. Further, an inorganic material such as a siloxane bond formed by solidifying a solution obtained by hydrolytic polymerization of a solution containing an inorganic material such as a metal alkoxide, ceramic precursor polymer or metal alkoxide by a sol-gel method, or a combination thereof. An inorganic material can be used.
In addition, a sealing material may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

[II-3. Configuration of light emitting device]
The other configurations of the light emitting device of the present invention are not particularly limited as long as the first light emitting body and the second light emitting body described above are provided. Usually, the first light emitting body described above is formed on an appropriate frame. And a second light emitter. At this time, the second light emitter is excited by the light emission of the first light emitter (that is, the first and second phosphors are excited) to emit light, and the first light emitter emits light. And / or it arrange | positions so that light emission of a 2nd light-emitting body may be taken out outside. In this case, the first phosphor and the second phosphor are not necessarily mixed in the same layer. For example, the second phosphor is contained on the layer containing the first phosphor. For example, the phosphor may be contained in a separate layer for each color development of the phosphor, such as by stacking layers.

  In the light emitting device of the present invention, members other than the first light emitter, the second light emitter, and the frame described above may be used. An example thereof is a sealing material. As a specific example, the sealing material can be used for the purpose of bonding the first light emitter, the second light emitter, and the frame in the light emitting device. In addition, as a sealing material, the thing similar to what was illustrated as a constituent material of a 2nd light-emitting body can be used, for example.

[II-4. Embodiment of Light Emitting Device]
Hereinafter, the light-emitting device of the present invention will be described in more detail with reference to specific embodiments. However, the present invention is not limited to the following embodiments, and does not depart from the gist of the present invention. It can be implemented with arbitrary modifications.

  FIG. 1 is a diagram schematically showing a configuration of a light emitting device according to an embodiment of the present invention. The light emitting device 1 of the present embodiment absorbs a part of light emitted from the frame 2, a blue LED (first light emitter) 3 that is a light source, and the blue LED 3, and emits light having a wavelength different from that. It comprises a fluorescent light emitting part (second light emitter) 4.

  The frame 2 is a metal base for holding the blue LED 3 and the fluorescent light emitting unit 4. On the upper surface of the frame 2, a trapezoidal concave section (dent) 2A having an opening on the upper side in FIG. Thereby, since the frame 2 has a cup shape, the light emitted from the light emitting device 1 can have directivity, and the emitted light can be used effectively. Furthermore, the inner surface of the recess 2A of the frame 2 is enhanced in light reflectance in the entire visible light region by metal plating such as silver. Can be discharged in a predetermined direction.

  A blue LED 3 is installed as a light source at the bottom of the recess 2 </ b> A of the frame 2. The blue LED 3 is an LED that emits blue light when supplied with electric power. Part of the blue light emitted from the blue LED 3 is absorbed as excitation light by the light emitting substance (first phosphor and second phosphor) in the fluorescent light emitting unit 4, and another part emits light. It is discharged from the device 1 in a predetermined direction.

  The blue LED 3 is installed at the bottom of the recess 2A of the frame 2 as described above. Here, the frame 2 and the blue LED 3 are bonded by a silver paste (a mixture of silver particles in an adhesive) 5. Thus, the blue LED 3 is installed on the frame 2. Further, the silver paste 5 also plays a role of efficiently radiating heat generated in the blue LED 3 to the frame 2.

  Further, a gold wire 6 for supplying power to the blue LED 3 is attached to the frame 2. That is, the electrode (not shown) provided on the upper surface of the blue LED 3 is connected by wire bonding using the wire 6, and when the wire 6 is energized, power is supplied to the blue LED 3. It emits blue light. One or a plurality of wires 6 are attached in accordance with the structure of the blue LED 3.

Furthermore, a fluorescent light emitting unit 4 that absorbs a part of the light emitted from the blue LED 3 and emits light having a different wavelength is provided in the recess 2A of the frame 2. The fluorescent light emitting unit 4 is formed of a phosphor and a transparent resin (sealing material). In the present embodiment, the phosphor is a substance that is excited by the blue light emitted from the blue LED 3 and emits light having a longer wavelength than the blue light. The phosphor constituting the fluorescent light emitting unit 4 may be a single type or a mixture of plural, and the sum of the light emitted from the blue LED 3 and the light emitted from the phosphor light emitting unit 4 has a desired color. Choose to be. The color is not limited to white, but may be yellow, orange, pink, purple, blue-green, or the like. Further, it may be an intermediate color between these colors and white. Here, a yellow fluorescent material (first fluorescent material) and a red fluorescent material (second fluorescent material) made of the fluorescent material of the present invention are used as the fluorescent material, and light bulb color light is emitted from the light emitting device. Suppose that
Moreover, transparent resin is a binder of the fluorescence light emission part 4, and uses the above-mentioned sealing material here.

  The mold unit 7 functions as a lens for protecting the blue LED 3, the fluorescent light emitting unit 4, the wire 6 and the like from the outside and controlling the light distribution characteristics. The mold part 7 mainly uses an epoxy resin.

  Since the light emitting device of the present embodiment is configured as described above, when the blue LED 3 emits light, the yellow phosphor and the red phosphor in the phosphor light emitting section 4 are excited to emit light. As a result, the light emitting device emits light of a light bulb color composed of blue light emitted from the blue LED 3, yellow light emitted from the yellow phosphor, and red light emitted from the red phosphor.

  At this time, in the light emitting device of this embodiment, the phosphor of the present invention having excellent temperature characteristics is used as the yellow phosphor. For this reason, even if the blue LED 3 generates heat, the luminance of the light emitted from the yellow phosphor does not significantly decrease. As a result, it is possible to suppress a decrease in the light emission intensity of the light emitting device due to the heat generated by the blue LED 3, and the light emitting device emits light. It is possible to prevent the color from changing due to a decrease in the luminance of yellow light.

The light-emitting device of the present invention is not limited to the above-described embodiment, and can be implemented with any changes without departing from the gist thereof.
For example, a surface-emitting type can be used as the first light emitter, and a film-like one can be used as the second light emitter. In this case, it is preferable to have a shape in which the film-shaped second light emitter is in direct contact with the light emitting surface of the first light emitter. In addition, contact here means producing the state which the 1st light-emitting body and the 2nd light-emitting body have touched exactly without passing air or gas. As a result, it is possible to avoid a light amount loss in which light from the first light emitter is reflected by the film surface of the second light emitter and oozes out, so that the light emission efficiency of the entire apparatus can be improved.

FIG. 2 is a schematic perspective view showing an example of a light emitting device in which a surface light emitting type is used as the first light emitter and a film-like one is applied as the second light emitter. In the light-emitting device 8 shown in FIG. 2, a surface-emitting GaN-based LD 10 as a first light-emitting body is provided on a substrate 9, and a film-shaped second light-emitting body 11 is formed on the surface-emitting GaN-based LD 10. Has been. Here, in order to create a state where they are in contact with each other, the LD 10 as the first light emitter and the second light emitter 11 are prepared separately, and their surfaces are brought into contact with each other by an adhesive or other means. Alternatively, the second light emitter 11 may be formed (molded) on the light emitting surface of the LD 10. As a result, the LD 11 and the second light emitter 11 can be brought into contact with each other.
According to the light-emitting device 8 having such a configuration, in addition to the same advantages as those of the above-described embodiment, it is possible to improve the light emission efficiency by avoiding the loss of light amount.

[II-5. Application of light emitting device]
The application of the light-emitting device of the present invention is not particularly limited, and can be used in various fields where a normal light-emitting device is used. Among these, since the temperature characteristics are good, the light emitting device of the present invention is particularly preferably used as a light source of an image display device and a lighting device. In addition, when using the light-emitting device of this invention as a light source of an image display apparatus, using with a color filter is preferable.

  An example of a surface emitting illumination device 12 incorporating the light emitting device 1 is schematically shown in FIG. In the surface light emitting illumination device 12, a large number of light emitting devices 1 are provided on the bottom surface of a rectangular holding case 13 whose inner surface is light-opaque such as a white smooth surface, and a power source for driving the light emitting device 1 is provided on the outside thereof. And a circuit or the like (not shown). In order to make the light emission uniform, a diffuser plate 14 such as a milky white acrylic plate is fixed to a portion corresponding to the lid portion of the holding case 13.

  When the surface emitting illumination device 12 is used, the light emitting device 1 emits light. This light is transmitted through the diffusion plate 14 and emitted upward in the drawing, and illumination light with uniform brightness can be obtained within the surface of the diffusion plate 14 of the holding case 13.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these, unless it deviates from the summary.

[About raw materials]
As raw materials for the crystal matrix, lanthanum nitride powder and silicon nitride powder (average particle size 0.5 μm, oxygen content 0.93% by weight, α-type content 92%) were used. On the other hand, cerium nitride powder or cerium oxide powder synthesized by nitriding metal cerium in ammonia was used as a material for the activator element.

[Example 1]
The cerium nitride powder, lanthanum nitride powder, and silicon nitride powder were weighed by the weight (g) shown in Table 1, respectively. Here, CeN and LaN are weighed 24% more than the theoretical values. Subsequently, after mixing for 10 minutes with an agate pestle and mortar, the resulting mixture was molded into pellets with a diameter of 6.5 mm by applying a pressure of 150 kg / cm ² using a molding machine, and placed in a boron nitride crucible. I put it in. The powder weighing, mixing, molding, and filling steps were all performed in a glove box capable of maintaining a nitrogen atmosphere with a moisture content of 1 ppm or less and oxygen of 1 ppm or less.

The boron nitride crucible containing the raw material was set in an electric furnace of graphite resistance heating type. In the firing operation, first, the firing atmosphere is evacuated by a diffusion pump, heated from room temperature to 800 ° C. at a rate of 20 ° C. per minute, and nitrogen at a temperature of 800 ° C. is introduced with a purity of 99.999% by volume. The temperature was raised to 1950 ° C. at 20 ° C. per minute and held at 1950 ° C. for 2 hours. The sample obtained after firing was coarsely pulverized and then pulverized using a mortar and pestle made of a sintered silicon nitride, and Ce _0.1 La _2.9 Si ₆ N ₁₁ powder (the molar ratio of Ce and La was Including an error of about 25%).

Table 1 shows the raw materials and the charged weight, and Table 2 shows the charged molar ratio. Table 2 also shows the relative X-ray diffraction main peak of each phase, which is a measure of how much La ₃ Si ₆ N ₁₁ phase and LaSi ₃ N ₅ phase are generated in the obtained sample. Intensity, oxygen concentration in the phosphor obtained by elemental analysis, and emission characteristics obtained by measurement of excitation spectrum and emission spectrum are shown. In Table 2, the emission characteristics were measured by blue excitation for the yellow emission peak and near ultraviolet excitation for the blue emission peak. Each excitation wavelength is as shown in Table 2.

In addition, the excitation spectrum and emission spectrum of the phosphor prepared in Example 1 were compared with Y ₃ Al ₅ O ₁₂ : Ce (ie, YAG; manufactured by Kasei Optonics, product No. P46-Y3). FIG. 4 shows the excitation spectrum and emission spectrum of the phosphor prepared in Example 1 (indicated as La ₃ Si ₆ N ₁₁ : Ce in FIG. 4) and YAG. The excitation spectrum and emission spectrum were measured using a fluorescence measuring apparatus F-4500 manufactured by Hitachi, Ltd. Specifically, a three-dimensional spectrum of excitation and emission was taken, and after determining the excitation peak position and emission peak position, the emission spectrum and excitation spectrum were precisely measured at each peak position.
FIG. 4 shows that the phosphor manufactured in Example 1 can be excited even at wavelengths in the near ultraviolet region. In FIG. 4, the vertical axis represents the normalized intensity obtained by normalizing the peak intensity with the maximum emission peak size.

In addition, it can be seen from FIG. 4 that the emission spectrum of the phosphor produced in Example 1 covers almost the entire emission region of YAG and extends to a lower wavelength region than YAG. From this point, it can be seen that the phosphor produced in Example 1 has the advantage that the color rendering properties can be improved.
In addition, when the half value width was calculated | required about the phosphor of Example 1 and the emission spectrum of YAG, it was 132 nm in Example 1, and 129 nm in YAG. Also from this point, it can be seen that the phosphor manufactured in Example 1 has an advantage that the color rendering property can be improved.
Further, the x value and y value of the chromaticity coordinates of the phosphor of Example 1 were 0.453 and 0.525, respectively.

[Examples 2 to 5 and Comparative Examples 1 to 3]
In Examples 2 to 5 and Comparative Examples 1 to 3, experiments were performed in the same manner as in Example 1 except that the raw materials and the charged weight thereof were different. The raw materials and their charged weights are shown in Table 1, and the charged molar ratios are shown in Table 2. Table 2 also shows the relative intensities of the X-ray diffraction main peaks of each phase, which is a measure of how much La ₃ Si ₆ N ₁₁ phase and LaSi ₃ N ₅ phase are generated in the obtained sample. The oxygen concentration in the phosphor obtained by elemental analysis and the emission characteristics obtained by measurement of the excitation spectrum and emission spectrum are shown. In Table 2, the emission characteristics were measured with blue light excitation for the yellow emission peak and near ultraviolet light excitation for the blue emission peak. Each excitation wavelength is as shown in Table 2. The relative intensity of the luminescence peak was determined as the intensity of the yellow and / or blue luminescence peak of Examples 2 to 5 and Comparative Examples 1 to 3, with the intensity of the yellow luminescence peak of Example 1 being 100.

As can be seen from Table 2, when CeO ₂ is used as a raw material, the smaller the amount, the lower the oxygen concentration in the sample, the less the generation of LaSi ₃ N ₅ phase, and the generation of La ₃ Si ₆ N ₁₁ phase. The amount increases. Accordingly, it can be seen that the blue emission intensity derived from the LaSi ₃ N ₅ phase decreases and the yellow emission intensity derived from the La ₃ Si ₆ N ₁₁ phase increases. On the other hand, when CeN is used as a raw material, it can be seen that the yellow emission intensity is strong regardless of the molar ratio in which it is used. Furthermore, as seen in Comparative Examples 1 to 3, it can be seen that the yellow emission intensity becomes zero when the molar ratio of CeO ₂ is 0.15 or more. From the above, it can be seen that the lower the oxygen concentration, the better the emission intensity in the yellow emission region.

FIG. 5 shows the excitation spectrum and emission spectrum of the phosphor manufactured in Example 1 using 0.036 mol of CeN and the phosphor manufactured in Comparative Example 1 using 0.061 mol of CeO ₂ . Show. In FIG. 5, the vertical axis indicates the relative intensity of light emission. From FIG. 5, it was found that yellow light emission can be obtained by reducing the oxygen concentration in the phosphor, such as using CeN as the Ce source. Further, from the excitation spectrum shown in FIG. 5, the phosphor (La ₃ Si ₆ N ₁₁ phase) produced in Example 1 is excited in both the near-ultraviolet region and the blue region, but the phosphor produced in Comparative Example 1 ( It can be seen that (LaSi ₃ N ₅ phase) is excited in the near ultraviolet region but not excited in the blue region.

[Example 6]
The phosphor prepared in Example 2 was stirred with 20 mL of aqua regia for 10 minutes, allowed to stand for 14 hours, washed with water, dried, pulverized, then stirred again with 20 mL of aqua regia for 3 hours and 40 minutes, washed with water and dried. Then, the excitation spectrum and the emission spectrum were measured, and the emission characteristics of the phosphor treated with aqua regia were obtained. The measured excitation spectrum and emission spectrum are shown in FIG. FIG. 6 also shows the excitation spectrum and emission spectrum of the phosphor prepared in Example 2. In FIG. 6, the vertical axis indicates the relative intensity of light emission. FIG. 6 shows that the blue LED excitation yellow emission intensity is increased 1.6 times by the aqua regia treatment.

Moreover, the X-ray diffraction pattern was measured for the phosphors produced in each of Example 2 and Example 6. The measurement results are shown in FIG. From FIG. 7, the phosphor produced in Example 2 includes a different phase other than the La ₃ Si ₆ N ₁₁ phase. However, the phosphor produced in Example 7 has almost all the different phases removed by aqua regia treatment, La ₃ Si ₆ N ₁₁ can see that the phosphor closer to the single phase is obtained, a blue LED excitation yellow phosphor _La 3 _Si 6 _N 11: it became clear that Ce.

Table 3 shows the light emission characteristics of the phosphors produced in Example 2 and Example 6, respectively.

[Example 7]
The experiment was performed in the same manner as in Example 4 except that the raw material powder was not molded. The light emission characteristics are shown in Table 4. It turns out that blue LED excitation yellow luminescence intensity is also high in the case of powder.

[Example 8]
Using the phosphor treated with aqua regia in Example 6, the luminance was measured by the following method, and the temperature characteristics were evaluated. For comparison, YAG was similarly evaluated.
<Evaluation of temperature characteristics>
A phosphor is excited at 455 nm, which is the dominant wavelength of a GaN-based blue light-emitting diode, in a nitrogen atmosphere, at 24 ° C. before heating, and at each temperature set by heating, using a luminance meter BM-5A manufactured by Topcon Corporation Luminance was measured.

  The results are shown in FIG. In FIG. 8, the luminescence intensity at each measurement temperature is shown as the relative intensity when the luminescence intensity at 24 ° C. is 100 as the vertical axis (maintenance rate (%)). From FIG. 8, it can be seen that the phosphor manufactured in Example 6 is superior in temperature characteristics because the maintenance ratio of luminance is high even when the temperature is higher than that of the conventional phosphor YAG. .

The use of the phosphor of the present invention is not particularly limited and can be used in various fields where ordinary phosphors are used. However, by utilizing the property of excellent temperature characteristics, such as near-ultraviolet LED and blue LED It is suitable for the purpose of realizing a general illuminator that is excited by a light source.
Further, the light emitting device of the present invention using the phosphor of the present invention having the above-described characteristics can be used in various fields where a normal light emitting device is used. And particularly preferably used.

It is a figure which shows typically the structure of the light-emitting device which concerns on one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view showing an embodiment of the present invention, showing an example of a light-emitting device using a surface-emitting type as a first light emitter and a film-like one as a second light emitter. is there. BRIEF DESCRIPTION OF THE DRAWINGS It is shown about one Embodiment of this invention, and is a figure which shows typically an example of the surface emitting illumination device incorporating the light-emitting device. It is a figure which shows the excitation spectrum and emission spectrum of the fluorescent substance and YAG which were produced in Example 1 of this invention. It is a figure which shows the excitation spectrum and emission spectrum of the fluorescent substance produced in Example 1 and Comparative Example 1 of this invention. It is a figure which shows the excitation spectrum and emission spectrum of the fluorescent substance produced in Example 2 and Example 6 of this invention. It is a figure which shows the X-ray-diffraction pattern of the fluorescent substance produced in Example 2 and Example 6 of this invention. It is a figure showing the evaluation result of the temperature characteristic in Example 8 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 Frame 2A The recessed part of a frame 3 Blue LED (1st light-emitting body)
4 Fluorescent light emitter (second light emitter)
5 Silver paste 6 Wire 7 Mold part 8 Light-emitting device 9 Substrate 10 Surface-emitting GaN-based LD (first light emitter)
DESCRIPTION OF SYMBOLS 11 2nd light-emitting body 12 Surface emitting illuminating device 13 Holding case 14 Diffusion plate

Claims (7)

Containing a crystal phase having a chemical composition of the following formula [1],
The oxygen content in the phosphor is 1.53% by weight or less, and
A phosphor having an emission peak in a wavelength range of 480 nm or more and 650 nm or less.
^{_{Ce x M III 3-x M}} IV y X -III z [1]
(In the above formula [1],
M ^III is an element that enters a trivalent site together with Ce in the crystal structure of the formula [1] , 90 % by mole or more is occupied by a trivalent metal element, and the trivalent metal element contains Containing 90 mol% or more of La,
M ^IV is an element that enters a tetravalent site in the crystal structure of the formula [1] , and 90 mol% or more is occupied by a tetravalent metal element, and among the tetravalent metal elements, Containing 90 mol% or more of Si,
X- ^III represents an element that enters a -3 valent site in the crystal structure of the formula [1], and nitrogen represents an element that occupies 85 mol% or more;
x represents a number satisfying 0.001 ≦ x ≦ 0.4 ;
y is 5. 7 ≦ y ≦ 6. Represents a number satisfying 3 ,
z represents a number satisfying 10.5 ≦ z ≦ 11.6 . ) The phosphor according to claim 1, which emits yellow light. 3. The phosphor according to claim 1, wherein the phosphor has two or more excitation peaks in a wavelength range of 300 nm or more and 530 nm or less. The phosphor according to any one of claims 1 to 3 ,
A phosphor-containing composition comprising a liquid medium. A first light emitter, and a second light emitter that emits visible light by irradiation of light from the first light emitter,
The light emitting device, wherein the second light emitter contains at least one phosphor according to any one of claims 1 to 3 . An image display device comprising the light-emitting device according to claim 5 as a light source. An illumination device comprising the light emitting device according to claim 5 as a light source.

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