JP2007308605A - Fluorophor for electron beam excitation use, and color display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorophor for electron beam excitation use excellent in luminance and color purity. <P>SOLUTION: The fluorophor for electron beam excitation use contains both oxygen and nitrogen as its constituent elements and has a peak wavelength within the range of 400-500 nm in its emission spectrum when excited by electron beams. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a phosphor that emits light by electron beam excitation, and particularly to a display device using an electron beam such as a field emission display (hereinafter referred to as “FED”), a fluorescent display tube, a color cathode ray tube, or the like. The present invention relates to a phosphor that can be suitably used, and a color display device using the phosphor.

  In recent years, research and development on field emission display devices (FED) using field emission cathodes (FEC) have been actively conducted. Candidates for blue phosphors for FED include sulfide phosphors such as ZnS: Ag and ZnS: Ag, Cl. However, there is a problem that they deteriorate due to electron beam irradiation during excitation. Furthermore, deterioration of the electron emission ability of FEC due to the scattered matter generated by decomposition of ZnS by electron beam irradiation is also a major obstacle to practical use.

  Several proposals have been made to prevent the degradation of ZnS. For example, Patent Document 1 attempts to suppress degradation by co-activating Ag and Al in ZnS. However, the improvement of deterioration cannot be said to be sufficient, and it has not yet been put into practical use.

Therefore, in order to avoid the problem of the sulfide-based phosphor as described above, Y ₂ SiO ₅ : Ce, which is less deteriorated by electron beam irradiation, is being studied as a phosphor that can replace the ZnS-based phosphor. (See Patent Documents 2 to 4)
JP 2006-89699 A Japanese Patent Laid-Open No. 11-302640 JP 2001-271065 A JP 2003-55657 A

Y ₂ SiO ₅ : Ce can be said to be an excellent phosphor in that it does not decompose and scatter during electron beam irradiation and has durability against electron beam excitation irradiation. However, there is a disadvantage that the luminance is inferior to that of the ZnS phosphor.

The object of the present invention has been made in consideration of the above-mentioned problems, and emits blue light having sufficient luminance while durability at the time of electron beam irradiation is equal to or higher than that of Y ₂ SiO ₅ : Ce. It is another object of the present invention to provide a phosphor for electron beam excitation, and a color display device using the phosphor for electron beam excitation.

In order to solve the above-mentioned problems, the present inventors have made researches on various phosphor compositions, and as a result, phosphors containing oxygen and nitrogen as constituent elements have a Y ₂ SiO in durability during electron beam irradiation. ₅ : The present invention was completed by conceiving that it is a phosphor for electron beam excitation that emits blue light having sufficient luminance while being equivalent to or more than Ce.

That is, the first configuration for solving the above-described problem is
The phosphor for electron beam excitation includes oxygen and nitrogen as constituent elements and has a peak wavelength in a wavelength range of 400 nm to 500 nm in an emission spectrum when excited by an electron beam.

The second configuration is the phosphor described in the first configuration,
It is represented by the general formula MmAaBbOoNn: Z, where the M element is one or more elements having a valence of II, the A element is one or more elements having a valence of III, and the B element is an IV valence One or more elements having a valence of O, O is oxygen, N is nitrogen, and Z is one or more activators. .

A third configuration is the phosphor according to the second configuration,
5.0 <(a + b) / m <9.0, 0 ≦ a / m ≦ 2.0, 0 <o <n, n = 2 / 3m + a + 4 / 3b−2 / 3o It is a phosphor for excitation.

The fourth configuration is the phosphor according to the second or third configuration,
0 <a / m ≦ 2.0, 4.0 ≦ b / m ≦ 8.0, 6.0 ≦ (a + b) /m≦8.0, 0 <o / m ≦ 3.0 And a phosphor for electron beam excitation.

A fifth configuration is the phosphor according to any one of the second to fourth configurations,
A phosphor for electron beam excitation characterized by m = 1, a = x, b = (6-x), o = (1 + x), n = (8−x), and 0 <x ≦ 1. is there.

A sixth configuration is the phosphor according to any one of the second to fifth configurations,
M element is one or more elements selected from Mg, Ca, Sr, Ba, Zn, rare earth elements having a valence of II,
The element A is one or more elements selected from Al, Ga, In, Tl, Y, Sc, P, As, Sb, Bi,
B element is one or more elements selected from Si, Ge, Sn, Ti, Hf, Mo, W, Cr, Pb, Zr,
The element Z is a phosphor for electron beam excitation characterized by being one or more elements selected from rare earth elements or transition metal elements.

A seventh configuration is the phosphor according to any one of the second to sixth configurations,
M element is one or more elements selected from Mg, Ca, Sr, Ba, Zn,
The A element is one or more elements selected from Al, Ga, and In,
B element is Si and / or Ge;
The Z element is a phosphor for electron beam excitation characterized by being one or more elements selected from Eu, Ce, Pr, Tb, Yb, and Mn.

An eighth configuration is the phosphor according to any one of the second to seventh configurations,
The phosphor for electron beam excitation is characterized in that M element is Sr, A element is Al, B element is Si, and Z element is Eu.

A ninth configuration is the phosphor according to any one of the second to eighth configurations,
A phosphor for electron beam excitation characterized in that the value of z / (m + z), which is the molar ratio of M element to Z element, is 0.0001 or more and 0.5 or less.

A tenth configuration is the phosphor according to any one of the first to ninth configurations,
16.0 wt% or more, 25.0 wt% or less of Sr, 2.0 wt% or more, 9.0 wt% or less of Al, 0.5 wt% or more of 11.5 wt% or less of O, 2. A phosphor for electron beam excitation characterized by containing 23.0 wt% or more and 32.0 wt% or less of N and more than 0 and 3.5 wt% or less of Eu.

An eleventh configuration is the phosphor according to any one of the first to tenth configurations,
In the X-ray diffraction pattern by the powder method using CoKα ray, the Bragg angle (2θ) shows the strongest diffraction peak in the range of 35 ° to 37 °,
Furthermore, the Bragg angle (2θ) of the X-ray diffraction pattern by the powder method is 23.6 ° to 25.6 °, 33 ° to 35 °, 39.7 ° to 40.7 °, 43 ° to 44 °. There are two, two, one, and one characteristic diffraction peak in the range,
When the relative intensity of the diffraction peak with the strongest intensity found in the Bragg angle (2θ) range of 35 ° to 37 ° is 100%, the relative intensity of these diffraction peaks is 2.0% or more and 40% or less. It is a fluorescent substance for electron beam excitation characterized by the above-mentioned.

A twelfth configuration is the phosphor according to any one of the first to eleventh configurations,
The phosphor for electron beam excitation is characterized in that the crystal of the product phase contained in the phosphor has an orthorhombic structure.

A thirteenth configuration is the phosphor according to any one of the first to twelfth configurations,
A phosphor for electron beam excitation, wherein a crystal of a generation phase contained in the phosphor has a crystal system represented by a space group Imm2.

A fourteenth configuration is the phosphor according to any one of the first to thirteenth configurations,
The average particle diameter (D50) of the phosphor powder containing primary particles having a particle size of 10 μm or less and aggregates in which the primary particles aggregate is 1.0 μm or more and 10 μm. The phosphor for electron beam excitation characterized by the following.

A fifteenth configuration is the phosphor according to any one of the first to fourteenth configurations,
A phosphor for electron beam excitation characterized by having a half-value width of an emission spectrum of 50 nm or less.

A sixteenth configuration is the phosphor according to any one of the first to fifteenth configurations,
The phosphor for electron beam excitation is characterized in that the chromaticity coordinates of the emission color of the phosphor are 0.1 <x <0.2 and 0 <y <0.1.

A seventeenth configuration is the phosphor according to any one of the first to sixteenth configurations,
The phosphor for electron beam excitation is characterized in that the chromaticity coordinates of the emission color of the phosphor are 0.1 <x <0.2 and 0 <y <0.05.

  An eighteenth configuration is a color display device using the phosphor for electron beam excitation according to any one of the first to seventeenth configurations.

According to the phosphor according to any one of the first to seventeenth configurations, since the obtained phosphor contains nitrogen, when excited by an electron beam, the durability against the irradiated electron beam is Y. ₂ SiO ₅ : A phosphor having an emission spectrum in the blue range and having excellent emission efficiency, emission intensity, and luminance while being equivalent to or more than an oxide phosphor represented by ₂ SiO ₅ : Ce.

  Among these, according to the phosphor described in the fourteenth configuration, since the obtained phosphor is in a powder form, it can be easily crushed or applied to various places as a paste. Moreover, since the average particle diameter (D50) of the phosphor is 1.0 μm or more and 10.0 μm or less, the coating density can be increased, and a coating film having high emission intensity and luminance can be obtained. Furthermore, from the viewpoint of increasing the definition of the display, it is preferable that the average particle size of the phosphor powder is 10.0 μm or less.

  Further, according to the phosphors described in the fifteenth, sixteenth and seventeenth configurations, the color purity of the light emitted from the obtained phosphors is good, and therefore a color display device having a wide color reproduction range is manufactured. Can do.

  According to the color display device described in the eighteenth configuration, a color display device with improved luminance and resolution can be obtained.

Hereinafter, although embodiment of this invention is described, this invention is not limited to these.
The phosphor of this embodiment is an oxynitride phosphor containing oxygen, nitrogen, and an appropriate activator element as constituent elements. The oxynitride phosphor is excellent in electron beam irradiation resistance, and becomes an excellent blue phosphor by containing an appropriate activator element.

Here, the phosphor is preferably a phosphor having a host structure represented by the general formula MmAaBbOoNn: Z. Here, the M element is one or more elements selected from elements having a valence of II in the phosphor. The element A is one or more elements selected from elements having a valence of III in the phosphor. The element A is not necessarily an essential element, and even a phosphor having a host structure that does not contain the element A is equivalent to or more than Y ₂ SiO ₅ : Ce in durability during electron beam irradiation. A phosphor for electron beam excitation that emits blue light can be obtained. However, a phosphor having a host structure containing an A element is more preferable in terms of luminance of light emission than a phosphor not containing it. The B element is one or more elements selected from elements having an IV valence in the phosphor. O is oxygen. N is nitrogen. The Z element is an element that acts as an activator in the phosphor, and is one or more elements selected from rare earth elements or transition metal elements. The phosphor having such a configuration is a phosphor that exhibits an emission spectrum having a peak wavelength in a wavelength range of 400 nm to 500 nm when excited by an electron beam.

  Further, in the phosphor, (a + b) / m is in a range of 5.0 <(a + b) / m <9.0, a / m is in a range of 0 ≦ a / m ≦ 2.0, oxygen And nitrogen are preferably 0 <o <n, and nitrogen is preferably n = 2 / 3m + a + 4 / 3b-2 / 3o.

When the phosphor according to the present embodiment having the above-described features is excited by an electron beam, the durability against electron beam irradiation is equal to or higher than that of an oxide phosphor represented by Y ₂ SiO ₅ : Ce. However, highly efficient blue light emission can be obtained. Therefore, by applying the phosphor to an FED or the like, a color display device having a long lifetime and high luminance can be obtained.

The phosphor according to the present embodiment is more effective than the oxide phosphor represented by the Y ₂ SiO ₅ : Ce phosphor reported so far (see, for example, Patent Documents 2 to 4). Although the durability against electron beam irradiation at the time of line excitation is equal to or less than that, the luminance and the color purity are excellent, so that it is possible to produce a color display device with higher luminance and a wider color reproduction range. .

  The phosphor of this embodiment can emit light with high efficiency when excited with an electron beam. Although the detailed reason is unknown, it is generally considered as follows.

  First, in the phosphor of the present embodiment, in the general formula MmAaBbOoNn: Z, the values of m, a, b, o, n are 5.0 <(a + b) / m <9.0, 0 ≦ a / m ≦ 2.0, 0 <o <n, and n = 2 / 3m + a + 4 / 3b−2 / 3o, so that the activator serving as the emission center in the crystal structure of the phosphor has concentration quenching. Can exist regularly at a distance that does not occur. In addition, it is considered that the luminous efficiency is improved because the excitation energy used for light emission given by the excitation light is efficiently transmitted.

  Furthermore, when the phosphor has the above-described configuration, it has a chemically stable composition. Therefore, an impurity phase that does not contribute to light emission does not easily occur in the phosphor, and a decrease in light emission intensity is suppressed. It is thought that there is not. That is, when many impurity phases occur, the number of phosphors per unit area decreases, and furthermore, the generated impurity phases absorb excitation light and light generated from the phosphors, resulting in a decrease in luminous efficiency and high It is considered that the emission intensity cannot be obtained.

  That is, when (a + b) / m is in the range of 5.0 <(a + b) / m <9.0 and a / m is in the range of 0 ≦ a / m ≦ 2.0, the impurity phase becomes yellow or orange. Generation of a light emitting phase is avoided, and it is possible to avoid a decrease in blue emission intensity, which is preferable. Further, when the relationship between oxygen and nitrogen is 0 <o <n, vitrification that occurs when the molar ratio of oxygen is larger than the molar ratio of nitrogen can be avoided. It is preferable that the emission intensity can be prevented from lowering due to.

  In addition, in the phosphor having the composition of the general formula MmAaBbOoNn: Z, the M element is an element having a + II valence, the A element is a + III valence, the B element is an + IV valent element, and nitrogen is an element having a −III valence. From the above, when m, a, b, o, and n have a relationship of n = 2 / 3m + a + 4 / 3b−2 / 3o, the sum of the valences of the respective elements becomes zero, and the phosphor is stable. It becomes a compound and is preferable.

In the phosphor of the present embodiment, in the general formula MmAaBbOoNn: Z, the values of m, a, b, o, n are 5.0 <(a + b) / m <9.0, 0 ≦ a / m ≦ 2.0, 0 <o <n, n = 2 / 3m + a + 4 / 3b−2 / 3o, but 0 <a / m ≦ 2.0, 4.0 ≦ b. It is preferable that /m≦8.0, 6.0 ≦ (a + b) /m≦8.0, and 0 <o / m ≦ 3.0. This is because, by setting the optimum a and o within the above range depending on the values of m and b, the generation of impurity phases can be remarkably suppressed, and the deterioration of crystallinity due to vitrification can be avoided. It is. Further, when a / m is greater than 0 and less than or equal to 2.0, a structurally regular and stable network can be formed by the A element, the B element, oxygen, and nitrogen. However, even if the A element is not included in the matrix structure of the phosphor, a phosphor that emits blue light can be obtained. However, the case where the A element is included in the host structure of the phosphor is preferable because the luminous efficiency is increased. Further, when the values of m, a, b, o, and n take m = 1, a = x, b = (6-x), o = (1 + x), and n = (8−x), M The element has a more ideal structure surrounded by tetrahedrons of [SiN ₄ ] or [(Al, Si) (O, N) ₄ ], and the luminous efficiency of the phosphor is preferably increased. Here, x preferably takes a range of 0 <x ≦ 1.

  On the other hand, the M element is preferably one or more elements selected from Mg, Ca, Sr, Ba, Zn, and a rare earth element having a valence of II, and more preferably Mg, Ca, More preferably, the element is one or more elements selected from Sr, Ba, and Zn, and most preferably Sr or Ba. In any case, it is preferable that Sr is contained in the M element.

  The element A is preferably one or more elements selected from Al, Ga, In, Tl, Y, Sc, P, As, Sb, and Bi, and further selected from Al, Ga, and In. More preferably, the element is one or more elements, and most preferably Al. As Al, nitride AlN is used as a general heat transfer material or structural material, and it is preferable because it is easily available and inexpensive, and also has a low environmental load.

The B element is preferably one or more elements selected from Si, Ge, Sn, Ti, Hf, Mo, W, Cr, Pb, and Zr, and more preferably Si and / or Ge. And most preferably Si. As Si, nitride Si ₃ N ₄ is used as a general heat transfer material or structural material, and it is preferable because it is easily available and inexpensive, and also has a low environmental load.

Here, when the A element is not included and the B element is Si, a tetrahedral network having a [SiN ₄ ] structure is formed. Further, when the element A is included, the element A is Al, and the element B is Si, a network having a [(Al, Si) (O, N) ₄ ] structure is formed, and the raw material AlN Is not completely left as an unreacted raw material, but can be almost completely dissolved in a tetrahedral network having a [(Al, Si) (O, N) ₄ ] structure. Therefore, a network having a [SiN ₄ ] structure or a [(Al, Si) (O, N) ₄ ] structure can be formed in the host structure of the phosphor, and further, as described above, [(Al, In the case of having a Si) (O, N) ₄ ] structure, the luminance is preferably increased. Further, a part of the Al site is replaced with an element having a valence of III such as Ga or In, or a part of the Si site is valence of an IV valence such as Ge or Sn. Substitution with an element is also a preferable configuration. Also by adopting this configuration, the crystal structure is optimized and further improvement in luminance can be expected.

  The Z element is one or more elements selected from a rare earth element or a transition metal element, which is compounded in a form in which a part of the M element in the host structure of the phosphor is replaced, and is further Eu, Ce, Pr, Tb. One or more elements selected from Yb, Mb, and Mn are preferable. Among them, when Eu is used as the Z element, the phosphor is preferable because it exhibits high emission intensity.

  The amount of Z element added is the same as that of the phosphor of the present embodiment in the general formula MmAaBbOoNn: Zz (where 5.0 <(a + b) / m <9.0, 0 ≦ a / m ≦ 2.0, 0 <o < n, n = 2 / 3m + a + 4 / 3b-2 / 3o), the molar ratio z / (m + z) between the M element and the activator Z element is in the range of 0.0001 or more and 0.50 or less. Preferably there is. If the molar ratio z / (m + z) between the M element and the Z element is in this range, concentration quenching occurs due to the excessive content of the activator (Z element), thereby improving the luminous efficiency. On the other hand, it can be avoided that the emission contributing atoms are insufficient due to the fact that the activator (Z element) content is too low, thereby reducing the luminous efficiency. Furthermore, it is more preferable if the value of z / (m + z) is within the range of 0.001 or more and 0.30 or less. However, the optimum value in the range of the value of z / (m + z) varies slightly depending on the type of activator (Z element) and the type of M element. Furthermore, by controlling the amount of activator (Z element) added, the emission peak wavelength of the phosphor can be shifted and set, and the chromaticity required for the phosphor for the color display device can be adjusted. It is beneficial in some cases.

  Further, by selecting the Z element, the peak wavelength of light emission in the phosphor of the present embodiment can be varied, and by activating a plurality of different Z elements, the peak wavelength can be varied and further sensitized. As a result, the emission intensity and the luminance can be improved.

As a result of performing the composition analysis result of the phosphor of the present embodiment, 16.0 wt% or more and 25.0 wt% or less of Sr, 2.0 wt% or more and 9.0 wt% or less of Al, and 0 0.5 wt% or more and 11.5 wt% or less of O, 23.0 wt% or more and 32.0 wt% or less of N, and more than 0 and 3.5 wt% or less of Eu. However, an analysis error of ± 2.0% by weight is expected for Sr and Al, and the remaining weight is Si and other elements.
From the viewpoint of avoiding a decrease in emission intensity of the phosphor, the concentration of each element of Fe, Ni, Co in the phosphor is 100 ppm or less, and the concentrations of B (boron) and C (carbon) are 0.1 wt% or less. It is preferable that

  When the values of m, a, b, o, n of each element calculated from the composition analysis result are compared with the values of m, a, b, o, n calculated from the blending ratio of the raw materials used, It is considered that the deviation occurs due to the fact that a very small amount of raw material decomposes or evaporates during the firing, and further analysis errors. In particular, when calculating o, oxygen contained in the raw material from the beginning, oxygen adhering to the surface, oxygen mixed due to oxidation of the surface of the raw material during weighing, mixing and firing of the raw material Further, it is considered that moisture, oxygen, etc. adsorbed on the phosphor surface after firing are not taken into consideration. Further, in the case of firing in an atmosphere containing nitrogen gas and / or ammonia gas, it is considered that oxygen in the raw material is removed and replaced with nitrogen during firing, and there is a slight deviation in the value of o.

Next, the powder X-ray diffraction pattern shown by the phosphor of the present embodiment will be described with reference to FIG. FIG. 1 is registered in the powder X-ray diffraction pattern (upper pattern) of the phosphor in Example 1 to be described later as an example of the phosphor of the present embodiment and the JCPDS card (53-0636). Non-patent literature Mater. Chem. , 1999, 9 1019-1022, a comparison of the main peak Bragg angle (2θ) and intensity for the diffraction pattern (lower pattern) of the Sr ₂ Al ₂ Si ₁₀ O ₄ N ₁₄ crystal. is there.

As is apparent from the comparison of both the upper and lower patterns shown in FIG. 1, the entire main peaks of the phosphor of this embodiment and the Sr ₂ Al ₂ Si ₁₀ O ₄ N ₁₄ crystal described in the JCPDS card are shown. Patterns are similar. However, in detail, the peak of the phosphor of the present embodiment is compared with the main peak of the Sr ₂ Al ₂ Si ₁₀ O ₄ N ₁₄ crystal described in the JCPDS card. 2θ) shifts in the direction of increasing, and although both are similar, it is considered that they have crystal structures with different crystal plane spacings. Here, the factors that cause the difference between the crystal structures of the two are that there is a difference in the amount of oxygen present in the crystal structures of the two, and that in the phosphor of this embodiment, a part of Sr is replaced by Eu. It can be considered. However, since the overall pattern of the main peak is similar, the crystal of the generation phase of the phosphor of the present embodiment is also the same as the Sr ₂ Al ₂ Si ₁₀ O ₄ N ₁₄ crystal described in the JCPDS card. In addition, it is considered that it has an orthorhombic crystal system represented by a space group Imm2.

From the above, the present inventors have proposed that the phosphor of the present embodiment is similar to the Sr ₂ Al ₂ Si ₁₀ O ₄ N ₁₄ crystal described in the JCPDS card, but has a new crystal plane spacing difference. The phosphor structure of the present embodiment having the novel crystal structure is considered to have an X-ray diffraction pattern and a crystal axis length (lattice constant) indicated by the phosphor. ) And the unit volume of the crystal lattice.

  In the X-ray diffraction pattern by the powder method using CoKα rays, the phosphor obtained by the embodiment shows the strongest diffraction peak with a Bragg angle (2θ) in the range of 35 ° to 37 °. The Bragg angle (2θ) of the X-ray diffraction pattern by the powder method is in the range of 23.6 ° to 25.6 °, 33 ° to 35 °, 39.7 ° to 40.7 °, 43 ° to 44 °. 2, 2, 1, 1 characteristic diffraction peak, and the Bragg angle (2θ) is the relative intensity of the strongest diffraction peak found in the range of 35 ° to 37 °. When 100%, the relative intensity of these diffraction peaks is 2.0% or more and 40% or less. By satisfying this feature, it is possible to obtain a phosphor having higher emission efficiency when the maximum peak wavelength in the emission spectrum is in the range of 400 nm to 500 nm when excited with light in the wavelength range of 250 nm to 430 nm.

  In the X-ray diffraction pattern by the powder method, the Bragg angle (2θ) is in the range of 26 ° to 33 °, 38.7 ° to 39.7 °, 42.0 ° to 42.8 °. When the relative intensity of the diffraction peak with the highest intensity found in the range (2θ) of 35 ° to 37 ° is 100%, it is preferable that there is no diffraction peak with a relative intensity of 10% or more. This is because the diffraction peak seen in the above range is considered to be due to an impurity phase different from the phase showing the peak of the emission spectrum in the wavelength range of 400 nm to 500 nm. That is, if the amount of the impurity phase is small, it is considered that a high emission intensity can be obtained by avoiding a decrease in luminous efficiency due to absorption of excitation light or light generated from the phosphor due to the generated impurity phase. It is.

Furthermore, the present inventors conducted a crystal structure analysis of the phosphor sample by using the Rietveld method based on the powder X-ray measurement result together with the measurement of the XRD peak position. The Rietveld method compares the measured diffraction intensity of X-rays obtained from actual measurements with the diffraction intensity of X-rays obtained theoretically from a crystal structure model constructed by predicting the crystal structure. In order to reduce the difference between them, various structural parameters in the latter model are refined by the method of least squares to derive a more accurate model of the crystal structure. The Rietveld analysis used the program “Rietan-2000”, and the crystal structure of Sr ₂ Al ₂ Si ₁₀ O ₄ N ₁₄ described in JCPDS card 53-0636 was used as the reference crystal structure.

As a result of the crystal structure analysis by the Rietveld technique, in order to improve the light emission characteristics of the phosphor sample, the a-axis, b-axis, c-axis of the phosphor sample, and the lattice constant of each crystal lattice are Sr described in the JCPDS card. _The smaller the crystal structure of ₂ Al ₂ Si ₁₀ O ₄ N _{14 and} the smaller the volume, the better. On the other hand, non-patent literature Z. Anorg. Allg. Chem. , When compared to SrSi ₆ N ₈ crystal structure with a reported 2004,630,1729, a shaft of the phosphor sample, b-axis, c-axis, the crystal lattice SrSi ₆ N ₈ larger than the crystal structure, The larger the volume, the better. Although the detailed reason for this phenomenon is unknown, it is considered that the crystal lattice and volume are changed by replacing Si atoms and Al atoms or nitrogen atoms and oxygen atoms contained in the phosphor sample.

Furthermore, since the crystal lattice and volume of the crystal structure are related to the amounts of Al and oxygen contained in the crystal structure, the present inventors have found that the emission characteristics including the luminous efficiency of the phosphor are Al and oxygen. I came up with the point of view that quantity might have an effect. Then, since the amount of Al and oxygen defines the volume of the crystal lattice of the phosphor, it is conceived that there is a volume of the crystal lattice capable of obtaining a phosphor with high luminous efficiency, and the volume of the crystal lattice. There 345A ³ or 385A ³ or less, more preferably have found that the volume is 353A ³ or more 385A ³ or less. Furthermore, since the amount of Al or oxygen also defines the lattice constant of the crystal lattice of the phosphor, it is conceived that there is also a lattice constant of the crystal lattice that can obtain a phosphor with good luminous efficiency. However, it was found that a was 7.85 mm or more and 8.28 mm or less, b was 9.26 mm or more and 9.58 mm or less, and c was 4.80 mm or more and 4.92 mm or less. (In the present embodiment, the a-axis, b-axis, and c-axis are shown with reference to the JCPDS cart. Therefore, the order of the a-axis, b-axis, and c-axis is changed depending on how the atomic coordinates are used. Is also synonymous.)

When the phosphor according to the present embodiment is used in the form of powder, the phosphor includes primary particles having a particle size of 10 μm or less and aggregates in which the primary particles are aggregated, and the primary particles and the aggregates including the aggregates. The average particle size of the body powder is preferably 50 μm or less. This is because light emission is considered to occur mainly on the particle surface in the phosphor powder, and thus the average particle diameter (in this embodiment, the average particle diameter is the median diameter (D50)). This is because if it is 50 μm or less, a surface area per unit weight of the powder can be secured and a decrease in luminance can be avoided. Furthermore, the density of the powder can be increased even when the powder is made into a paste and applied to a light emitting element or the like, and a reduction in luminance can be avoided also from this viewpoint. Further, according to the study by the present inventors, although the detailed reason is unknown, it was also found that the average particle size is preferably larger than 1.0 μm from the viewpoint of the luminous efficiency of the phosphor powder.
From the above, the average particle size of the phosphor powder of the present embodiment is 1.0 μm or more and 50 μm or less, preferably 1.0 μm or more and 10 μm or less, more preferably 5.0 μm or more. The particle diameter is 30 μm or less. The average particle diameter (D50) here is a value measured by LS230 (laser diffraction scattering method) manufactured by Beckman Coulter. Further, the above aspect, the value of the specific surface area of the phosphor powder of the present embodiment (BET) is 0.05 m ² / g or more, is preferably not more than 5.00 m ² / g.

  The emission spectrum when the phosphor of the present embodiment is excited by an electron beam has a half width of 50 nm or less. The chromaticity coordinates of the light emitted from the phosphor are 0.1 <x <0.2 and 0 <y <0.1, and in particular, 0.1 <x <0.2 and 0 <y <0.1. 0.05 is preferred.

  The phosphor of this embodiment is suitable as a phosphor for exciting an electron beam because it has excellent emission intensity and luminance when excited by an electron beam. That is, a high-luminance color display device can be obtained by using the phosphor of this embodiment.

  Various color display devices can be manufactured by combining the powdered blue phosphor of the present embodiment with known green phosphors and red phosphors.

Examples of the green phosphor to be combined include Zn (Ga, Al) ₂ O ₄ : Mn, Y ₃ (Al, Ga) ₅ O ₁₂ : Tb, Y ₂ SiO ₅ : Tb, ZnS: Cu, and Al. This is not the case. Examples of the red phosphor to be combined include, but are not limited to, SrTiO ₃ : Pr, Y ₂ O ₃ : Eu, Y ₂ O ₂ S: Eu, and CaAlSiN ₃ : Eu.

Next, a manufacturing method of the phosphor according to the present _{embodiment, SrAl x Si 6-x O} 1 + x N 8-x: Eu ( where, x = 0.8, a Eu / (Sr + Eu) = 0.050. ) Will be described as an example.
Note that due to evaporation during the firing of the phosphor material, the charged composition of the material is different from the composition produced after firing. In particular, in firing at 1700 ° C. or higher and firing for a long time, Si ₃ N ₄ gradually sublimates by the firing, and therefore it is preferable to add more than the target molar ratio. However, since the sublimation amount varies depending on the firing conditions, the amount charged is preferably adjusted according to each firing condition. Therefore, in the following description, for the sake of convenience, a composition formula calculated from the blending ratio of the phosphor raw materials is shown. Therefore, in the present embodiment, the phosphor is marked with the composition formula SrAl _0.8 Si ₆ ON _8.8 : Eu at the time of charging the raw materials, and the manufacturing method will be described. Here, z / (m + z) and Eu / (Sr + Eu) have the same meaning. Note that the amount of oxygen contained in the activator element raw material at the time of preparation is negligible because it is small.

  In general, many phosphors are produced by a solid-phase reaction, and the method for producing the phosphor of this embodiment can also be obtained by a solid-phase reaction. However, the manufacturing method is not limited to these. The raw materials of M element, A element and B element may be commercially available raw materials such as nitrides, oxides, carbonates, hydroxides, basic carbonates, etc. Is prepared with 2N or more, more preferably 3N or more. In general, the particle diameter of each raw material particle is preferably a fine particle from the viewpoint of promoting the reaction, but the particle diameter and shape of the obtained phosphor also vary depending on the particle diameter and shape of the raw material. For this reason, a raw material such as a nitride having an approximate particle size may be prepared in accordance with the particle size and shape required for the finally obtained phosphor, preferably a particle size of 50 μm or less, more preferably A raw material having a particle diameter of 0.1 μm or more and 10.0 μm or less is preferably used. The raw material for the element Z is also preferably a commercially available nitride, oxide, carbonate, hydroxide, basic carbonate, or simple metal. Of course, the purity of each raw material is preferably higher, and 2N or more, more preferably 3N or more is prepared. In particular, when carbonate is used as a raw material for the M element, a flux effect is obtained without adding a compound composed of an element not included in the constituent elements of the phosphor of this embodiment as a flux (reaction accelerator). This is a preferable configuration.

In the production of the composition formula SrAl _0.8 Si _5.2 O _1.8 N _7.2 : Eu, the molar ratio of each element after firing is Sr: Al: Si: O: Eu = 0.950: 0. .8: 6.0: 1.0: 0.050 may be adjusted by adjusting the decrease in the raw material composition during firing. Here, mixing composition formula _{SrAl 0.8 Si 6 ON 8.8: Eu} ( however, Eu / (Sr + Eu) = 0.050) was prepared as a. SrCO ₃ (3N), Al ₂ O ₃ (3N), AlN (3N), Si ₃ N ₄ (3N) are prepared as raw materials for each element, for example, M element, A element, and B element, Eu ₂ O ₃ (3N) may be prepared as the Z element. These raw materials are weighed and mixed with 0.950 mol of SrCO ₃ , 0.80 mol of AlN, 2.0 mol of Si ₃ N ₄ and 0.050 / 2 mol of Eu ₂ O ₃ , respectively. Carbonate is used as the Sr raw material, whereas the oxide raw material has a high melting point and a flux effect cannot be expected. On the other hand, when a low melting point raw material such as carbonate is used, the raw material itself acts as a flux and reacts. This is because the light emission characteristics are improved. Note that a slight amount of C (carbon) may be added to the raw material to improve the reducibility at the time of firing. However, if a large amount of C remains in the fired sample, the emission characteristics are deteriorated. It is necessary to adjust so that the concentration of C contained in is 0.1% by weight or less. In addition, when an oxide is used as a raw material, an oxide such as chloride, fluoride, BaO or the like may be added as a flux to obtain a flux effect. It should be noted that it can worsen the characteristics of the body.

  The weighing and mixing may be performed in the air, but since the nitride of each raw material element is easily affected by moisture, it is convenient to operate in a glove box under an inert atmosphere from which moisture has been sufficiently removed. is there. The mixing method may be either wet or dry. However, when water is used as a solvent for wet mixing, the raw material is decomposed, and therefore an appropriate organic solvent or liquid nitrogen must be selected. The apparatus may be a normal apparatus using a ball mill or a mortar.

  The mixed raw material is put into a crucible, and is fired while being held at 1600 ° C. or higher, more preferably 1700 ° C. or higher and 2000 ° C. or lower for 30 minutes or longer while circulating an atmospheric gas in a firing furnace. When the firing temperature is 1600 ° C. or higher, it is possible to obtain a phosphor excellent in light emission characteristics by proceeding with a solid phase reaction well. Moreover, if it bakes at 2000 degrees C or less, it can prevent that excessive sintering and melting | fusing occur. In addition, since a solid-phase reaction advances rapidly, so that a calcination temperature is high, holding time can be shortened. On the other hand, even when the firing temperature is low, the desired light emission characteristics can be obtained by maintaining the temperature for a long time. However, the longer the firing time, the more the particle growth proceeds and the larger the particle shape. Therefore, the firing time may be set according to the target particle size. Also, by firing the phosphor prepared by firing in multiple steps, the composition is made uniform, and the number of fine particles with weak emission intensity decreases due to the progress of the solid-phase reaction. The desired light emission characteristics can be obtained. Also, by sealing the firing furnace during firing, excess oxygen in the phosphor sample can be released and maintaining an appropriate phosphor composition by firing without passing the nitrogen atmosphere through the furnace. Since the effect of suppressing the phenomenon that oxygen is reduced beyond the amount of oxygen necessary for the above can be obtained, the target emission intensity can be obtained. As a method for sealing the firing furnace, a method of covering the crucible loaded with the phosphor sample is simple and preferable, but since the sealing effect can be obtained by stopping the circulation of the atmosphere gas, the circulation of the atmosphere gas is possible. Even if the method is stopped for a predetermined time, the sealing effect can be obtained similarly.

  The atmospheric gas to be circulated in the firing furnace is not limited to nitrogen but may be any of inert gases such as rare gases, ammonia, a mixed gas of ammonia and nitrogen, or a mixed gas of nitrogen and hydrogen. However, if oxygen is contained in the atmospheric gas, the phosphor particles undergo an oxidation reaction. Therefore, the oxygen contained as impurities is as small as possible, for example, preferably 100 ppm or less. Furthermore, when moisture is contained in the atmospheric gas, the phosphor particles undergo an oxidation reaction during firing as in the case of oxygen. Therefore, the moisture contained as impurities is as small as possible, for example, preferably 100 ppm or less. Here, nitrogen gas is preferable when a single gas is used as the atmospheric gas. Baking by using ammonia gas alone is possible, but ammonia gas is more expensive than nitrogen gas, and because it is a corrosive gas, special treatment is required for the equipment and exhaust method at low temperatures. When ammonia is used, it is preferable to use ammonia at a low concentration, such as a mixed gas with nitrogen. For example, when a mixed gas of nitrogen gas and ammonia is used, it is preferable that nitrogen is 80% or more and ammonia is 20% or less. Also, when using a mixed gas of nitrogen and other gas, if the gas concentration other than nitrogen increases, the partial pressure of nitrogen in the atmospheric gas decreases, so from the viewpoint of promoting the nitriding reaction of the phosphor, An inert or reducing gas containing 80% or more of nitrogen is preferably used.

  Furthermore, it is preferable to provide a state in which the atmospheric gas described above is flowed at a flow rate of, for example, 0.1 ml / min or more during the firing. This is because gas is generated from the raw material during the firing of the phosphor raw material, but the above-mentioned inert gas such as nitrogen and rare gas, ammonia, a mixed gas of ammonia and nitrogen, or a mixed gas of nitrogen and hydrogen By flowing an atmosphere containing one or more kinds of gases selected from the above, it is possible to prevent the gas generated from the raw material from filling the furnace and affecting the reaction. As a result, the phosphor This is because it is possible to prevent a decrease in light emission characteristics. In particular, when materials that decompose into oxides at high temperatures, such as carbonates, hydroxides, basic carbonates, etc., are used as phosphor materials, the amount of gas generated is large. It is preferable to adopt a configuration for exhausting the generated gas.

  On the other hand, in the phosphor raw material firing stage in phosphor production, the pressure in the firing furnace is preferably a pressurized state so that atmospheric oxygen does not enter the furnace. However, if the pressurization exceeds 1.0 MPa (in this embodiment, the pressure in the furnace means the pressurization from atmospheric pressure), a special pressure-resistant design is required for the design of the furnace equipment. Therefore, in consideration of productivity, the pressure is preferably 1.0 MPa or less. Further, when the pressure is increased, sintering between the phosphor particles proceeds excessively, and pulverization after firing may become difficult. Therefore, the furnace pressure during the firing is preferably 1.0 MPa or less, and more preferably Is preferably 0.001 MPa or more and 0.1 MPa or less.

Incidentally, _Al 2 _{O 3} crucible as the crucible, _Si 3 _{N 4} crucible, AlN crucible, sialon crucible, C (carbon) crucible, such as BN (boron nitride) crucible, is used as available in a gas atmosphere as described above Of these, a nitride crucible is preferable, and a BN crucible is particularly preferable because it is possible to avoid contamination of impurities from the crucible. As the amount of impurities contained after firing, it is preferable that B (boron) and / or C is 0.1% by weight or less without impairing light emission characteristics.

After the firing is completed, the fired product is taken out from the crucible and ground to a predetermined average particle size using a grinding means such as a mortar and a ball mill, and the composition formula SrAl _0.8 Si _5.2 O _1.8. A phosphor represented by N _7.2 : Eu can be manufactured. Thereafter, the obtained phosphor is subjected to washing, classification, surface treatment, and heat treatment as necessary. As a cleaning method, cleaning in an acidic solution using hydrofluoric acid, hydrochloric acid, sulfuric acid, nitric acid or the like is preferable because metal atoms such as Fe adhering to the particle surface and raw material particles remaining unreacted are dissolved. Here, the amount of Fe, Ni and Co contained in the obtained phosphor is preferably 100 ppm or less.

  When other elements are used as the M element, A element, B element, and Z element, and when the activation amount of the Z element that is the activator is changed, the blending amount at the time of charging each raw material is predetermined. By adjusting to the composition ratio, the phosphor can be manufactured by the same manufacturing method as described above. However, depending on the firing conditions, evaporation, sublimation, and the like of the raw material occur during firing, so the raw materials are mixed and fired in consideration of the raw material charge composition.

Hereinafter, based on an Example, this invention is demonstrated more concretely.
Example 1
First, a sample according to Example 1 was manufactured by the following procedure.
SrCO ₃ (3N), AlN (3N), Si ₃ N ₄ (3N), and Eu ₂ O ₃ (3N) were prepared, and the molar ratio of each element was Sr: Al: Si: Eu = 0.950: 0. 8: 6: each raw material so that 0.050, a SrCO ₃ 0.950mol, AlN and 0.8 mol, the _Si 3 _{N 4} 2mol, the _Eu 2 _{O 3} 0.050 / was 2mol weighed in air And mixed using a mortar. Since SrCO ₃ decomposes into SrO during firing, the amount of oxygen was calculated as SrO. The mixed raw material is put in a BN crucible, and the inside of the furnace is evacuated once. Then, in a flowing nitrogen atmosphere (flow state, 20.0 L / min), the furnace pressure is increased to 1700 ° C. at a pressure of 0.05 MPa at 15 ° C./min. After heating and holding at 1700 ° C. for 3 hours and baking, the temperature was lowered from 1700 ° C. to 50 ° C. for 1 hour 30 minutes. Thereafter, the fired sample was crushed using a mortar until the particle size became appropriate in the air. The crushed sample is put again in the BN crucible, left in the furnace with the BN crucible covered, and once evacuated in the furnace, in a flowing nitrogen atmosphere (flow state, 20.0 L / min) The temperature was increased from 15 MPa / min to 1800 ° C. at a furnace pressure of 0.05 MPa, held at 1800 ° C. for 3 hours and fired, and then cooled from 1800 ° C. to 50 ° C. over 1 hour 30 minutes. Thereafter, the fired sample is pulverized in the atmosphere using a mortar until an appropriate particle size is obtained, and a phosphor sample represented by a composition formula SrAl _0.8 Si _5.2 O _1.8 N _7.2 : Eu. Got. The composition is different from the charged composition. This is because the sublimation of Si and the reduction of oxygen occurred during firing, resulting in a composition with less Si and oxygen than the blending ratio of raw materials (charged composition ratio). Conceivable. The average particle diameter (D50) of the obtained phosphor was 8.5 μm.

  The produced phosphor of Example 1 was ultrasonically dispersed in ion-exchanged water and applied on a transparent glass plate on which an ITO film was formed by a precipitation method, and the emission characteristics of the phosphor of Example 1 by electron beam excitation were observed. It was set as the sample to evaluate. The produced substrate sample was irradiated with an electron beam under conditions of acceleration voltages of 300 V, 800 V and 1200 V, and the luminance of light emitted from the substrate sample was measured with a luminance meter. The measurement results are shown in Table 1. Further, with respect to the manufactured phosphor of Example 1, an emission spectrum was measured when an electron beam was irradiated under an acceleration voltage of 1200V. The measurement results are shown in Table 2 and FIG.

(Comparative Example 1)
Using Y ₂ SiO ₅ : Ce, which is a blue phosphor for FED, as the phosphor of Comparative Example 1, a substrate sample of Comparative Example 1 was produced in the same manner as in Example 1, and an acceleration voltage of 300 V was applied to the produced substrate sample. , 800 V and 1200 V were irradiated with an electron beam, and the luminance of light emitted from the substrate sample was measured with a luminance meter. The measurement results are shown in Table 1. Further, with respect to the manufactured phosphor of Comparative Example 1, an emission spectrum was measured when an electron beam was irradiated under the condition of an acceleration voltage of 1200V. The measurement results are shown in Table 2 and FIG.

(Contrast of Example 1 and Comparative Example 1)
As is clear from Table 1, the phosphor of Example 1 had higher brightness than Y ₂ SiO ₅ : Ce according to Comparative Example 1 under any acceleration voltage condition. The phosphor of Example 1 is considered to be suitable as a blue phosphor of a color display device using a phosphor for electron beam excitation because it exhibits higher luminance than a conventional phosphor. 2A and 2B, the emission spectrum of the phosphor of Example 1 has an emission spectrum with a narrow half-value width only in a region closer to blue. It can be seen that the emission spectrum of Y ₂ SiO ₅ : Ce has a long tail to the long wavelength side.

  Here, although details will be described later, as described above, the phosphor according to Example 1 has an advantage that the color purity is good because it has an emission spectrum with a narrow half-value width only in a region closer to blue. However, since the phosphor according to Comparative Example 1 does not substantially have a light emitting component on the long wavelength side of 500 nm or longer, it is apparently disadvantageous in terms of luminance. This is because the visual sensitivity of the human eye is not flat, and as the light emission wavelength is changed from 555 nm to a shorter wavelength, even the light having the same light emission intensity is perceived as having lower luminance. As described above, since the color purity and the luminance cancel each other, when judging the superiority or inferiority of the phosphors having different color purity, it is difficult to say which is generally superior in the comparison of only the luminance.

  Nevertheless, while the phosphor according to Example 1 is excellent in color purity, it already shows higher luminance than the conventional phosphor according to Comparative Example 1. Therefore, it was considered that the superiority would be further clarified by comparing the luminance when it was assumed that the color purity was the same condition, so the following examination was performed.

For phosphors emitting blue light, there is a method of comparing values obtained by dividing the value of luminance Y by the value of chromaticity coordinate y as a method of comparing the luminance when the color purity is assumed to be the same. Table 2 shows values obtained by dividing the value of luminance Y by the value of chromaticity coordinate y. As a result, the value of (luminance Y / chromaticity coordinate y) of the phosphor of Example 1 is 4033, and the value of (luminance Y / chromaticity coordinate y) of the conventional phosphor in Comparative Example 1 is 4033. It was found that the value was about three times as large as a certain 1453. In other words, when the comparison is made on the assumption that the phosphor of Example 1 has the same color purity, it is considered that the luminance is three times higher than that of the conventional phosphor.
From the above, since the phosphor of Example 1 exhibits high luminance while having the same or higher durability against electron beam irradiation than the conventional phosphor, color display using the phosphor Since the brightness of the device is improved, it can be said that the phosphor is extremely excellent as a blue phosphor for a color display device.

(Chromaticity comparison)
As is apparent from the results of Table 2 and FIGS. 2A and 2B, the phosphor according to Example 1 emits light in a region closer to blue than Y ₂ SiO ₅ : Ce according to Comparative Example 1. It was found to have a spectrum. Furthermore, the phosphor according to Example 1 was found to have a very sharp emission spectrum as compared with the conventional blue phosphor for electron beam excitation. Whereas the half-value width of the emission spectrum of conventional Y ₂ SiO ₅ : Ce is 75 nm or more, the half-value width of the phosphor according to Example 1 is as narrow as 33.3 nm, and the blue phosphor has an extremely good color purity. It turns out that. Moreover, the result of having compared the chromaticity coordinate of the light which the fluorescent substance which concerns on Example 1 and Comparative Example 1 emits on a chromaticity coordinate is shown in FIG. A triangle surrounded by a broken line is a color television color range defined by the NTSC standard. Normally, color displays such as CRT, PDP, and FED are designed to reproduce the color range defined by the NTSC standard as much as possible using phosphors of three colors of RGB. Since the triangle connecting the chromaticity coordinates of the RGB phosphors used in the display becomes the color reproduction range of the display as it is, if a phosphor whose chromaticity coordinates are outside the NTSC standard triangle color range is used A display with a wide color reproduction range is desirable. For the blue phosphor, a chromaticity coordinate range of 0.1 <x <0.2 and 0 <y <0.1 is desirable. As apparent from Table 2 and FIG. 3, the chromaticity coordinates of the phosphor according to Example 1 are x = 0.153, y = 0.045, and 0.1 <x <0.2 and 0. Since it is in the chromaticity coordinate range of <y <0.1, it can be said that this is a very excellent phosphor as a phosphor for color display.

(Comparison of electron beam irradiation ability of phosphors)
The light emission characteristic evaluation sample by the electron beam excitation of the phosphor according to Example 1 and Comparative Example 1 described above was continuously irradiated with an electron beam for 15 minutes under the condition of an acceleration voltage of 1400 V, and the irradiation time was 6 minutes, 9 minutes, 12 The brightness value at 15 minutes was measured for 15 minutes. Then, for each sample, the value of relative luminance after each irradiation time when the luminance at the start of irradiation (initial luminance) was normalized to 100 was obtained as “luminance maintenance ratio”. The measurement result of the luminance maintenance rate is shown in Table 4 and FIG. FIG. 4 is a graph in which the vertical axis represents the luminance maintenance rate and the horizontal axis represents the electron beam irradiation time. The phosphor according to Example 1 is plotted with ◆ and connected with a solid line, and the phosphor according to Comparative Example 1 is marked with ■. Plotted with a dotted line and connected with a broken line. As is clear from the results in Table 4 and FIG. 4, the phosphor according to Example 1 showed a higher value than the luminance maintenance rate of the phosphor according to Comparative Example 1 at all electron beam irradiation times. . From the measurement results, it was found that the phosphor according to Example 1 is superior in durability to electron beam irradiation than the phosphor according to Comparative Example 1.

(Examination of X-ray diffraction pattern and crystal structure of phosphor)
Next, the X-ray diffraction pattern by the powder method was measured for the phosphor sample according to Example 1. The results are shown in FIG. In FIG. 1, the X-ray diffraction pattern measurement result of the phosphor according to Example 1 is shown on the upper side, and the X-ray diffraction pattern of the JCPDS card (53-0636) is shown on the lower side.
The X-ray diffraction pattern shown on the upper side of FIG. 1 is obtained by filling the phosphor according to Example 1 so that the material is flat on a holder made of titanium, and applying it to “RINT 2000” manufactured by Rigaku Denki Co., Ltd. It was obtained by measuring.

  As is apparent from the results of the X-ray diffraction pattern by the powder method in FIG. 1, diffraction peaks could be confirmed in the Bragg angle (2θ) range of 25 ° to 35 ° and 40 ° to 45 °.

Furthermore, Rietveld analysis was performed on the phosphor according to Example 1 based on the crystal structure of Sr ₂ Al ₂ Si ₁₀ O ₄ N ₁₄ reported in the JCPDS card (53-0636).

The crystal structure of Sr ₂ Al ₂ Si ₁₀ O ₄ N ₁₄ reported in the JCPDS card (53-0636) is an orthorhombic system represented by the space group Imm2, and the lattice constant is a = 8.279Å, b = 9.576 Å and c = 4.916 Å. Here, according to the analysis result of the phosphor of Example 1, the crystal structure is similarly orthorhombic and space group Imm2, but the lattice constants are a = 7.904９０, b = 9.321Å, and c = 4. The crystal unit cell was much smaller than what the JCPDS card had previously reported. Why the lattice constant is smaller than the value of the JCPDS _card, in the phosphor generation phase of Example 1 represented by the composition formula _{SrAl x Si 6-x O 1} + x N 8-x, the value of x is 1 or less It is considered that the lattice is contracted because the composition has a composition in which oxygen atoms are lost even if the composition is taken or x = 1.

On the other hand, non-patent literature Z. Anorg. Allg. Chem. , 2004, 630, 1729, the SrSi ₆ N ₈ crystal structure has an orthorhombic crystal similar to the Sr ₂ Al ₂ Si ₁₀ O ₄ N ₁₄ crystal described in the JCPDS card. However, due to the small number of Al atoms and oxygen atoms, the lattice constants are reported as a = 7.855Å, b = 9.260Å, and c = 4.801Å, which are higher than the phosphor obtained in this Example 1. Furthermore, it has a small lattice constant.

From the above, the phosphors of Example 1 are Sr ₂ Al ₂ Si ₁₀ O ₄ N ₁₄ and Z.P. Anorg. Allg. Chem. , 2004, 630, and 1729, a new crystal structure having a different crystal plane spacing is obtained by changing the abundance of Al or oxygen atoms, although it is similar to the crystal structure of SrSi ₆ N _8. and _is a novel phosphor having a composition formula represented by _{SrAl x Si 6-x O 1} + x N 8-x. Therefore, in order to obtain a phosphor with good luminous efficiency, the volume of the crystal lattice is between the crystal structure of Sr ₂ Al ₂ Si ₁₀ O ₄ N _{14 and} the crystal structure of SrSi ₆ N ₈ , that is, crystal volume is 345A ³ or more, it is 385A ³ or less, more preferably in the lattice constant of each crystal lattice, a is 7.85Å above, 8.28A or less, b is 9.26Å above, 9.58A or less, c May be 4.80 mm or more and 4.92 mm or less. The range of x is preferably 0 ≦ x ≦ 1.0.

(Study of phosphor composition analysis, particle size, true density)
The composition analysis result, particle size, and true density of the phosphor sample manufactured in Example 1 were examined. Table 3 shows the results of composition analysis, average particle diameter, and specific surface area for each phosphor.

First, regarding the results of the composition analysis shown in Table 3, although there is a difference between the theoretical value obtained from the composition ratio of the constituent elements and the composition formula SrAl _x Si _6-x O _{1 + x} N _8−x , the example 1, the value is equal to the value when x = 0.8. The cause of the deviation may be due to a measurement error or impurities mixed in the phosphor preparation. However, due to Si ₃ N ₄ existing as impurities in the sample, the apparent ratio of Sr and Al is low. It is also thought to be because. Therefore, by controlling the manufacturing conditions and reducing the amount of Si ₃ N ₄ present as an impurity, it is considered that a more efficient phosphor can be obtained with a more optimized crystal structure. The concentration of Fe, Ni, and Co elements in the phosphor sample of Example 1 is 100 ppm or less, and the concentration of C (carbon) and B (boron) is also 200 ppm or less. There were very few analysis results.

  Further, when the average particle diameter (D50) of the phosphor sample of Example 1 was measured by a laser diffraction scattering method, as shown in Table 3, the average particle diameter was 8.50 μm, which was 1.0 μm or more, 10 0.0 μm or less. Therefore, when the phosphor sample of Example 1 is applied as a paste, the application density can be increased, and a coating film having high emission intensity and high luminance can be obtained.

Further, when the true density measurement was performed on the phosphor sample of Example 1, as shown in Table 3, it was found that the true density was 3.47 g / cc. For the measurement of the true density, an Ultrapycnometer 1000 manufactured by QUANTACHROME was used. In the ideal Sr ₂ Al ₂ Si ₁₀ O ₄ N ₁₄ structure described in the literature, the true density shows a value around 3.60 g / cc, but the true density of the phosphor is lower than the ideal value. It became. This is probably because the produced phosphor sample of Example 1 has a structure in which oxygen is deficient or less than the theoretical composition as shown in the composition analysis result. That is, the true density is reduced by the amount of deficient or reduced oxygen atoms, or the production phase of the phosphor sample is mixed with Si ₃ N ₄ having a low true density. It is also thought that has declined. However, since the phosphor sample of Example 1 shows good light emission characteristics as described above even when oxygen atoms are missing and an impurity phase is contained, the true density of the phosphor of the embodiment is It has been found that a range of 3.40 g / cc to 3.65 g / cc is sufficient.

4 is a graph showing measurement results obtained by measuring an X-ray diffraction pattern by a powder method for the phosphor sample according to Example 1. (A) The graph which shows the emission spectrum of the fluorescent substance which concerns on Example 1, (B) The graph which shows the emission spectrum of the fluorescent substance which concerns on the comparative example 1. It is the graph which showed the chromaticity coordinate of the light which the fluorescent substance concerning Example 1 and Comparative Example 1 emitted on the chromaticity coordinate. 6 is a graph showing the luminance maintenance ratio after the electron beam irradiation of the phosphors according to Example 1 and Comparative Example 1.

Claims (18)

  A phosphor for electron beam excitation, which contains oxygen and nitrogen as constituent elements and has a peak wavelength in a wavelength range of 400 nm to 500 nm in an emission spectrum when excited by an electron beam. The phosphor according to claim 1,
It is represented by the general formula MmAaBbOoNn: Z, where the M element is one or more elements having a valence of II, the A element is one or more elements having a valence of III, and the B element is an IV valence A phosphor for electron beam excitation, characterized in that one or more elements having a valence of O, O is oxygen, N is nitrogen, and Z is one or more activators. The phosphor according to claim 2, wherein
5.0 <(a + b) / m <9.0, 0 ≦ a / m ≦ 2.0, 0 <o <n, n = 2 / 3m + a + 4 / 3b−2 / 3o Phosphor for excitation. The phosphor according to claim 2 or 3, wherein
0 <a / m ≦ 2.0, 4.0 ≦ b / m ≦ 8.0, 6.0 ≦ (a + b) /m≦8.0, 0 <o / m ≦ 3.0 A phosphor for electron beam excitation. The phosphor according to any one of claims 2 to 4,
A phosphor for electron beam excitation, wherein m = 1, a = x, b = (6-x), o = (1 + x), n = (8−x), and 0 <x ≦ 1. The phosphor according to any one of claims 2 to 5,
M element is one or more elements selected from Mg, Ca, Sr, Ba, Zn, rare earth elements having a valence of II,
The element A is one or more elements selected from Al, Ga, In, Tl, Y, Sc, P, As, Sb, Bi,
B element is one or more elements selected from Si, Ge, Sn, Ti, Hf, Mo, W, Cr, Pb, Zr,
A phosphor for electron beam excitation, wherein the Z element is one or more elements selected from rare earth elements and transition metal elements. The phosphor according to any one of claims 2 to 6,
M element is one or more elements selected from Mg, Ca, Sr, Ba, Zn,
The A element is one or more elements selected from Al, Ga, and In,
B element is Si and / or Ge;
A phosphor for electron beam excitation, wherein the Z element is one or more elements selected from Eu, Ce, Pr, Tb, Yb, and Mn. The phosphor according to any one of claims 2 to 7,
A phosphor for electron beam excitation, wherein the M element is Sr, the A element is Al, the B element is Si, and the Z element is Eu. The phosphor according to any one of claims 2 to 8,
A phosphor for electron beam excitation, wherein a value of z / (m + z), which is a molar ratio of M element to Z element, is 0.0001 or more and 0.5 or less. The phosphor according to any one of claims 1 to 9,
16.0 wt% or more, 25.0 wt% or less of Sr, 2.0 wt% or more, 9.0 wt% or less of Al, 0.5 wt% or more of 11.5 wt% or less of O, 2. A phosphor for electron beam excitation, comprising 23.0 wt% or more and 32.0 wt% or less of N and more than 0 and 3.5 wt% or less of Eu. The phosphor according to any one of claims 1 to 10,
In the X-ray diffraction pattern by the powder method using CoKα ray, the Bragg angle (2θ) shows the strongest diffraction peak in the range of 35 ° to 37 °,
Furthermore, the Bragg angle (2θ) of the X-ray diffraction pattern by the powder method is 23.6 ° to 25.6 °, 33 ° to 35 °, 39.7 ° to 40.7 °, 43 ° to 44 °. There are two, two, one, and one characteristic diffraction peak in the range,
When the relative intensity of the diffraction peak with the strongest intensity found in the Bragg angle (2θ) range of 35 ° to 37 ° is 100%, the relative intensity of these diffraction peaks is 2.0% or more and 40% or less. A phosphor for electron beam excitation characterized by the above-mentioned. The phosphor according to any one of claims 1 to 11,
A phosphor for electron beam excitation, wherein a crystal of a product phase contained in the phosphor has an orthorhombic structure. The phosphor according to any one of claims 1 to 12,
A phosphor for electron beam excitation, wherein a crystal of a generation phase contained in the phosphor has a crystal system represented by a space group Imm2. The phosphor according to any one of claims 1 to 13,
The average particle diameter (D50) of the phosphor powder containing primary particles having a particle size of 10 μm or less and aggregates in which the primary particles aggregate is 1.0 μm or more and 10 μm. The phosphor for electron beam excitation characterized by the following. The phosphor according to any one of claims 1 to 14,
A phosphor for electron beam excitation, wherein a half width of an emission spectrum is 50 nm or less. The phosphor according to any one of claims 1 to 15,
A phosphor for electron beam excitation, characterized in that the chromaticity coordinates of the emission color of the phosphor are 0.1 <x <0.2 and 0 <y <0.1. The phosphor according to any one of claims 1 to 16,
A phosphor for electron beam excitation, characterized in that the chromaticity coordinates of the emission color of the phosphor are 0.1 <x <0.2 and 0 <y <0.05. A color display device using the phosphor for electron beam excitation according to any one of claims 1 to 17.

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