Silicate phosphor, light-emitting device, and method for producing silicate phosphor

Abstract

Provided are a silicate phosphor, a light-emitting device, and a method for producing the silicate phosphor. The silicate phosphor has a composition represented by formula (1). (In formula (1), A1 is at least one first alkali metal element selected from the group consisting of Rb and Cs, A2 is at least one second alkali metal element selected from the group consisting of K, Na and Li, M1 is at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Y and La, and w, x and y each satisfy 0 lt; wlt; 1.0, 0 lt; x is less than or equal to 0.125, w + x is less than or equal to 1.0, 0 lt And y < = 0.08. ) A < 11-w-x > A < 2 > w M < 1 > x (Li < 3 > SiO4): Eu < y > (1)

Description

Technical Field

[0001] The present invention relates to a silicate phosphor, a light-emitting device, and a method for manufacturing a silicate phosphor. Background Art

[0002] For example, in a light-emitting device for a backlight of a display device, the range of color reproducibility needs to be further expanded. In order to expand the range of color reproducibility, there is a case where a phosphor having a narrower wavelength width (full width at half maximum) of a light-emitting peak in the emission spectrum is required.

[0003] As a phosphor that emits green light for a light-emitting device, for example, a β-sialon phosphor having a composition represented by the formula Si ,

[0008] ,

[0013] ,

[0009] , w , ,

[0011] , 1-w-x , ,

[0012] , x ,

[0010] , 1 , , 2 , , , 1 ,

[0006] , ,

[0007] , , , y Al z O z N 8-z (where 0 < z ≤ 4.2).

[0004] In addition, for example, in Patent Document 1, a orthosilicate phosphor activated with europium is disclosed as a phosphor that emits green light.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2019-527760 <00​​​​​​​​​​​​​​​​​​​​​​​​​​​​​(1)

[0014] (In the above formula (1), A 1 is at least one first alkali metal element selected from Rb and Cs, A 2 is at least one second alkali metal element selected from K, Na and Li, M 1 is at least one element selected from Mg, Ca, Sr, Ba, Y and La, and w, x and y are respectively 0 <w<1.0、0<x≤0.125、w+x≤1.0、0<y≤0.08。)

[0015] A second aspect relates to a light-emitting device comprising:

[0016] The above-mentioned silicate phosphor, and

[0017] The light-emitting element has a light emission peak wavelength in the range of 300 nm to 500 nm, and irradiates the silicate phosphor with excitation light.

[0018] A third aspect relates to a method for producing a silicate phosphor, the method comprising:

[0019] Prepare the raw materials, which include:

[0020] Contains at least one first alkali metal element A selected from Rb and Cs 1 The first compound,

[0021] Contains at least one second alkali metal element A selected from K, Na and Li 2 The second compound,

[0022] Contains at least one element M selected from Mg, Ca, Sr, Ba, Y and La 1 The third compound,

[0023] A fourth compound containing Li,

[0024] A fifth compound containing Si, and

[0025] The sixth compound containing Eu,

[0026] At least one compound among the first to sixth compounds is an oxide;

[0027] The first alkali metal element A contained in the first compound 1 The second alkali metal element A contained in the second compound 2 , the element M contained in the third compound 1, Li contained in the fourth compound, Si contained in the fifth compound, and Eu contained in the sixth compound are mixed in a molar ratio satisfying the composition represented by the following formula (1) to obtain a raw material mixture; and

[0028] The raw material mixture is subjected to a first heat treatment at a first temperature within a range of 400° C. to 800° C. in a reducing atmosphere to obtain a first heat-treated product having a composition represented by the following formula (1).

[0029] A 1 1-w-x A 2 w M 1 x (Li3SiO4):Eu y (1)

[0030] (In the above formula (1), w, x and y satisfy 0 <w<1、0<x≤0.125、w+x≤1.0、0<y≤0.08。)

[0031] Effects of the Invention

[0032] According to the present invention, a silicate phosphor having a narrow full width at half maximum (FWHM) emission peak in its emission spectrum, high emission intensity, and high light resistance, a light-emitting device, and a method for producing the silicate phosphor can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 2 is a schematic cross-sectional view showing an example of a light emitting device.

[0034] Figure 2 It is a graph showing the emission spectra of each silicate phosphor of Examples 1 to 4 and the silicate phosphor of Comparative Example 1.

[0035] Figure 3 Graphs showing emission spectra of the silicate phosphor of Example 7 and the silicate phosphor of Comparative Example 2.

[0036] Figure 4 It is a graph showing the lumen maintenance rate of each silicate phosphor of Examples 2 and 7 and the silicate phosphor of Comparative Example 1 after continuous irradiation with excitation light for 500 hours.

[0037] Figure 5 Graphs showing the thermoluminescent spectra of the silicate phosphors of Examples 3 and 7 and the silicate phosphor of Comparative Example 1.

[0038] Figure 6 These are X-ray diffraction patterns of the silicate phosphors of Examples 1 to 11 and the silicate phosphors of Comparative Examples 1 and 2.

[0039] Figure 7 This is an X-ray diffraction pattern of each silicate phosphor of Examples 1 to 4, obtained by enlarging a portion where the diffraction angle 2θ (°) is 37° to 37.8°.

[0040] Explanation of symbols

[0041] 10: Light-emitting element

[0042] 20: 1st lead

[0043] 30: Second lead

[0044] 40: Molded body

[0045] 50: Wavelength conversion component

[0046] 70: Phosphor

[0047] 71: 1st phosphor

[0048] 72: Second phosphor

[0049] 100: Light-emitting device DETAILED DESCRIPTION

[0050] The silicate phosphor, light-emitting device, and method for manufacturing the silicate phosphor disclosed herein are described below based on embodiments. However, the embodiments shown below are examples for concretizing the technical concept of the present invention, and the present invention is not limited to the following silicate phosphor, light-emitting device, and method for manufacturing the silicate phosphor. It should be noted that in this specification, the relationship between color names and chromaticity coordinates, the relationship between the wavelength range of light and the color name of monochromatic light, etc. are all based on JIS Z8110. In this specification, the full width at half maximum refers to the wavelength width at which the luminous intensity reaches 50% relative to the luminous peak wavelength showing the maximum luminous intensity in the luminous spectrum.

[0051] The silicate phosphor has a composition represented by the following formula (1).

[0052] A 1 1-w-x A 2 w M 1 x (Li3SiO4):Eu y (1)

[0053] (In the above formula (1), A 1 is at least one first alkali metal element selected from Rb and Cs, A 2 is at least one second alkali metal element selected from K, Na and Li, M 1is at least one element selected from Mg, Ca, Sr, Ba, Y and La, and w, x and y are respectively 0 <w<1.0、0<x≤0.125、w+x≤1.0、0<y≤0.08。)

[0054] A silicate phosphor has a crystal structure comprising a 4-coordinate tetrahedral structure composed of silicate (SiO4) represented by (Li3SiO4) in formula (1) and lithium oxide, and an 8-coordinate cubic structure composed of an alkali metal element and oxygen. A silicate phosphor has a structure in which oxygen that constitutes the 4-coordinate tetrahedral structure and oxygen that constitutes the 8-coordinate cubic structure are shared (shared). The 4-coordinate tetrahedral structure is composed of silicate (SiO4) represented by (Li3SiO4) in formula (1) and lithium oxide, and the 8-coordinate cubic structure is composed of an alkali metal element and oxygen. The silicate phosphor has a structure in which a cubic structure with 8 oxygen atoms coordinated around an alkali metal element is present between the tetrahedral structure composed of silicate (SiO4) represented by (Li3SiO4) in formula (1) and lithium oxide. There are gaps of different sizes in the 4-coordinate tetrahedral structure composed of silicate (SiO4) and lithium oxide, and there is a first alkali metal element A with a larger ionic radius than K. 1 A in the center 1 A large cubic structure represented by O8 (RbO8 or CsO8), and a second alkali metal element A having an ion radius smaller than that of K 2 A in the center 2 O8 (KO8, NaO8 or LiO8) represented by a small cubic structure, the first alkali metal element A 1 is at least one selected from Rb and Cs, the second alkali metal element A 2 It is at least one selected from K, Na and Li.

[0055] It is speculated that Eu, the activating element of the silicate phosphor, is replaced by the first alkali metal element A. 1 or the second alkali metal element A 2 It is preferred that the silicate phosphor having the composition represented by the above formula (1) is excited by light in the wavelength range of 300 nm to 500 nm to emit fluorescence having a peak wavelength in the range of 520 nm to 560 nm. Therefore, it is presumed that Eu as the activating element is easily replaced by the second alkali metal element A having an ion radius closer to that of Eu. 2 The second alkali metal element A is replaced by 2 is at least one selected from K, Na and Li. Eu as the activation element is replaced by the first alkali metal element A 1 or the second alkali metal element A 2Replaced by and included in the crystal structure. Regarding the activation element Eu contained in the silicate phosphor, divalent Eu 2+ Helps to glow.

[0056] In the case of silicate phosphors, a first alkali metal element A having a larger ionic radius than K is present between the 4-coordinate tetrahedral structure composed of silicate (SiO4) and lithium oxide. 1 A large cubic structure centered on the ion radius of the second alkali metal element A with an ion radius smaller than that of K. 2 The crystalline structure is a cubic structure with a center of 2, and the oxygen that constitutes the tetrahedral structure of silicate (SiO4) and lithium oxide, as well as the oxygen that constitutes the large cubic structure and the small cubic structure are shared (common), so the crystal structure is easily distorted and defects are easily generated in the crystal structure. When the crystal structure of the silicate phosphor has defects, it is replaced by the first alkali metal element A. 1 Eu 2+ Easily converted to trivalent Eu 3+ , in order to achieve charge balance. 2+ Changes to trivalent Eu that does not contribute to luminescence 3+ , the luminous intensity decreases.

[0057] The silicate phosphor having the composition represented by the above formula (1) has a first alkali metal element A 1 Or the second alkali metal element A 2 A portion of M is replaced by a divalent or trivalent element M 1 The silicate phosphor having the composition represented by the above formula (1) has a first alkali metal element A 1 Or the second alkali metal element A 2 A portion of M is replaced by a divalent or trivalent element M 1 , divalent Eu 2+ No need to convert to trivalent Eu 3+ To achieve charge balance, the divalent Eu in the silicate phosphor that contributes to luminescence can be retained. 2+ , thereby reducing the decrease in luminous intensity.

[0058] In the case of the silicate phosphor having the composition represented by the above formula (1), the first alkali metal element A is replaced by 1 A divalent or trivalent element M 1 , preferably having a first alkali metal element A 1 Elements with ionic radii similar to M 1 The first alkali metal element A that replaces at least one selected from Rb and Cs1 A divalent or trivalent element M 1 Preferably, at least one element M selected from Sr, Ba, Y and La 1 .

[0059] In the case of the silicate phosphor having the composition represented by the above formula (1), the second alkali metal element A is replaced by 2 The divalent element M 1 , preferably having a second alkali metal element A 2 Elements with ionic radii similar to M 1 A second alkali metal element A that replaces at least one selected from K, Na, and Li 2 The divalent element M 1 , preferably at least one element M selected from Mg and Ca 1 Compared to the first alkali metal element A 1 , the second alkali metal element A 2 The ionic radius is small, so the second alkali metal element A is replaced 2 The element M 1 It is preferred to have a second alkali metal element A 2 The ionic radius is close to the ionic radius of the divalent element M 1 , rather than a trivalent element.

[0060] In the case of the silicate phosphor having the composition represented by the above formula (1), the first alkali metal element A is replaced by 1 Or the second alkali metal element A 2 A divalent or trivalent element M 1 In order to achieve charge balance, the first alkali metal element A can be replaced 1 The element M 1 , or it can be replaced by the second alkali metal element A 2 The element M 1 , or by replacing the first alkali metal element A 1 and the second alkali metal element A 2 Two or more elements M 1 . Replace the first alkali metal element A 1 and the second alkali metal element A 2 At least one of the divalent or trivalent elements M 1 , preferably at least one element M selected from Mg, Ca, Sr, Ba, Y and La 1 In the case of the silicate phosphor having the composition represented by the above formula (1), the element M 1 Preferably, at least one element M selected from Mg and Ca having a small ionic radius 1, which is easier to replace the alkali metal element and is also easy to replace the second alkali metal element A with an ionic radius smaller than that of the first alkali metal element A 1 The second alkali metal element A 2 . In the silicate phosphor having the composition represented by the above formula (1), the element M 2 replacing the second alkali metal element A 1 is preferably Mg. In the silicate phosphor having the composition represented by the above formula (1), for example, when the second alkali metal element A 2 is Na, the divalent element M 2 replacing the second alkali metal element A 1 is preferably Mg having an ionic radius close to that of Na.

[0061] In the silicate phosphor having the composition represented by the above formula (1), the variable w represents the molar ratio of the second alkali metal element A 2 in 1 mole of the composition represented by the above formula (1). In the composition represented by the above formula (1), the variable w of the silicate phosphor exceeds 0 and is less than 1.0 (0 < w < 1.0), preferably in the range of 0.1 or more and 0.24 or less (0.1 ≤ w ≤ 0.24), more preferably in the range of 0.12 or more and 0.23 or less (0.12 ≤ w ≤ 0.23). In the silicate phosphor, when the variable w representing the molar ratio of the second alkali metal element A 2 in 1 mole of the composition represented by the above formula (1) is in the range of exceeding 0 and less than 1.0 (0 < w < 1.0), the large cubic structure centered on the first alkali metal element A 1 and the small cubic structure centered on the second alkali metal element A 2 are arranged between the tetrahedral structure of coordination number 4 formed by the silicate (SiO4) and lithium oxide represented by (Li3SiO4) in the above formula (1), and it is easy to form a stable crystal structure.

[0062] In the silicate phosphor having the composition represented by the above formula (1), the variable x represents the molar ratio of the element M 1 in 1 mole of the composition represented by the above formula (1). In the composition represented by the above formula (1), the variable x of the silicate phosphor exceeds 0 and is 0.125 or less (0 < x ≤ 0.125), preferably in the range of 0.01 or more and 0.125 or less (0.01 ≤ x ≤ 0.125), more preferably in the range of 0.02 or more and 0.125 or less (0.02 ≤ x ≤ 0.125), further preferably in the range of 0.02 or more and 0.10 or less (0.02 ≤ x ≤ 0.10). In the silicate phosphor, when representing the element M in 1 mole of the composition represented by the above formula (1) 1When the variable x of the molar ratio is in the range of more than 0 and 0.125 or less (0 < x ≤ 0.125), Eu as an activating element does not need to change from divalent Eu 2+ to trivalent Eu 3+ to achieve charge balance, and divalent Eu that contributes to luminescence in the silicate phosphor can be maintained 2+ , thereby reducing the decrease in luminescence intensity. The variable w representing the molar ratio of the second alkali metal element A 2 , and the sum of the variable x representing the molar ratio of the element M 1 is 1.0 or less (w + x ≤ 1.0).

[0063] In the silicate phosphor having the composition represented by the above formula (1), the variable y represents the molar ratio of the activating element Eu in 1 mole of the composition represented by the above formula (1). For the composition represented by the above formula (1), the variable y of the silicate phosphor is more than 0 and 0.08 or less (0 < y ≤ 0.08), preferably in the range of 0.01 or more and 0.08 or less (0.01 ≤ y ≤ 0.08), more preferably in the range of 0.02 or more and 0.07 or less (0.02 ≤ y ≤ 0.07), and further preferably in the range of 0.03 or more and 0.06 or less (0.03 ≤ y ≤ 0.06). In the silicate phosphor, when the variable y representing the molar ratio of Eu in 1 mole of the composition represented by the above formula (1) is in the range of more than 0 and 0.08 or less (0 < y ≤ 0.08), the amount of Eu that contributes to luminescence contained in the structure of the silicate phosphor is sufficient.

[0064] For the silicate phosphor having the composition represented by the above formula (1), the first alkali metal element A 1 preferably contains Rb, and the second alkali metal element A 2 preferably contains Na to achieve stabilization of the crystal structure. Regarding the large cubic structure centered on the first alkali metal element A 1 located between the four-coordinate tetrahedral structures composed of silicate (SiO4) and lithium oxide and the cubic structure centered on the second alkali metal element A 2 , when the first alkali metal element A 1 as the central element of the large cubic structure located between the tetrahedral structures contains Rb, and the second alkali metal element A 2 as the central element of the small cubic structure located between the above tetrahedral structures contains Na, voids in the tetrahedral structure and distortion between the large cubic structure and the small cubic structure are not likely to occur, thereby achieving stabilization of the crystal structure. For the silicate phosphor having the composition represented by the above formula (1), the first alkali metal element A 1 is more preferably Rb, and the second alkali metal element A2 Na is more preferred in order to stabilize the crystal structure.

[0065] In the case of the silicate phosphor having the composition represented by the above formula (1), the element M 1 It is preferable to contain Mg. In the silicate phosphor having the composition represented by the above formula (1), when the element M 1 When Mg is contained, the crystal structure of the silicate phosphor, which is prone to defects, is preliminarily filled with a divalent element M. 1 Substitute for the second alkali metal element A 2 , which can reduce the divalent Eu as an activation element that contributes to luminescence 2+ To trivalent Eu 3+ The change of luminescence intensity can be maintained, thereby improving the light resistance of the silicate phosphor. 1 When Mg is included, divalent Mg can not only reduce the divalent Eu required for charge balance, but also 2+ Towards trivalent Eu 3+ changes, and because Mg has the same 2 The ionic radius of the element M is close to that of the element M, so it is easy to stabilize the crystal structure, suppress the defects of the crystal structure, and maintain the luminescence intensity. 1 More preferably, it is Mg. In the silicate phosphor having the composition represented by the above formula (1), when the first alkali metal element A 1 Contains Rb, second alkali metal element A 2 When Na is included, the element M 1 May contain Mg, element M 1 It can also be Mg. In the silicate phosphor having the composition represented by the above formula (1), when the first alkali metal element A 1 Rb, the second alkali metal element A 2 When it is Na, the element M 1 May contain Mg, element M 1 Mg may also be used.

[0066] In the thermoluminescence spectrum (luminescence curve) obtained by thermoluminescence measurement, the thermoluminescence intensity (hereinafter also referred to as "TL intensity") of the silicate phosphor having the composition represented by the above formula (1) in the range of 550K or above is preferably as low as possible. Regarding the thermoluminescence spectrum (luminescence curve) of the phosphor obtained by thermoluminescence measurement, the electrons captured by the defect energy level caused by the defects in the crystal structure are transferred to the Eu as the luminescence center.2+ The TL intensity is proportional to the concentration of the defect level. It can be considered that the source of the electrons captured by the defect level comes from Eu 2 + , which can also be used as Eu 3+ In thermoluminescence spectroscopy, if the TL intensity in the range above 550K can be suppressed, the number of electrons captured by defect levels will be reduced, thereby reducing the decrease in luminescence intensity.

[0067] In the silicate phosphor having the composition represented by the above formula (1), in the thermoluminescence spectrum (luminescence curve) obtained by thermoluminescence measurement, the ratio TLa / TLp of the average value TLa of the TL intensity in the range of 560 K to 580 K to the value TLp of the maximum TL intensity in the range of 240 K to 350 K is preferably 0.25 or less. When the ratio TLa / TLp of the average value TLa of the TL intensity in the range of 560 K to 580 K to the value TLp of the maximum TL intensity in the range of 240 K to 350 K in the thermoluminescence spectrum (luminescence curve) of the silicate phosphor having the composition represented by the above formula (1) is 0.25 or less, the TL intensity in the range of 550 K or more can be suppressed, thereby reducing the decrease in luminescence intensity. For the silicate phosphor having a composition represented by the above formula (1), in the thermoluminescent spectrum, the ratio TLa / TLp of the average value TLa of the TL intensity in the range of 560K to 580K to the maximum TL intensity value TLp in the range of 240K to 350K is more preferably less than 0.20, further preferably less than 0.15, and further preferably less than 0.10.

[0068] The silicate phosphor having the composition represented by the above formula (1) is excited by light in a wavelength range of greater than 300 nm and less than 500 nm, and preferably emits fluorescence having a luminescence peak wavelength in the range of greater than 520 nm and less than 560 nm, more preferably emits fluorescence having a luminescence peak wavelength in the range of greater than 520 nm and less than 550 nm, and further preferably emits fluorescence having a luminescence peak wavelength in the range of greater than 520 nm and less than 540 nm.

[0069] The average particle size (Fisher Sub-Sieve Siezer's Number) of the silicate phosphor measured by the Fisher Sub-Sieve Sizer method (hereinafter also referred to as the "FSSS method") can be in the range of 1 μm to 45 μm, or in the range of 3 μm to 42 μm, in the range of 5 μm to 40 μm, or in the range of 10 μm to 35 μm. When the average particle size measured by the FSSS method is in the range of 1 μm to 45 μm, the silicate phosphor has excellent luminescence characteristics and can improve operability when manufacturing light-emitting devices. The FSSS method is a method for measuring specific surface area based on the air permeation method using the flow resistance of air, and is mainly used to determine the particle size of primary particles.

[0070] Silicate phosphors can also be used in combination with other phosphors that emit green, yellow, red, and deep red light, or by mixing light from an excitation light source and light from each phosphor to obtain white light for a light-emitting device.

[0071] The light-emitting device includes the silicate phosphor and a light-emitting element having a peak emission wavelength in the range of 300 nm to 500 nm and capable of irradiating the silicate phosphor with excitation light.

[0072] Figure 1 2 is a schematic cross-sectional view showing an example of a light emitting device.

[0073] The light-emitting device 100 includes a molded body 40 having a recess, a light-emitting element 10 disposed within the recess of the molded body 40, and a wavelength conversion member 50 covering the light-emitting element 10. The molded body 40 is formed by integrally molding a first lead 20, a second lead 30, and a resin portion comprising a thermosetting resin, a thermoplastic resin, or a UV-curable resin. The molded body 40 has the first and second leads 20, 30 disposed thereon, forming the bottom surface of the recess, and the resin portion disposed thereon, forming the side surfaces of the recess. The light-emitting element 10 is mounted on the bottom surface of the recess of the molded body 40. The light-emitting element 10 has a pair of positive and negative electrodes electrically connected to the first and second leads 20, 30, respectively, via wires 60. The light-emitting element 10 is covered by the wavelength conversion member 50. The wavelength conversion member 50 includes a phosphor 70 comprising a silicate phosphor that converts the wavelength of light emitted by the light-emitting element 10, which serves as an excitation light source. Phosphor 70 may include a first phosphor 71 comprising a silicate phosphor and a second phosphor 72 having a different composition than the first phosphor. Wavelength conversion member 50 not only functions as a wavelength conversion member but also serves to protect light-emitting element 10 and phosphor 70 comprising a silicate phosphor from the external environment. Light-emitting device 100 emits light by receiving external power via first lead 20 and second lead 30.

[0074] As the excitation light source of the light-emitting device, a light-emitting element can be used. The peak emission wavelength of the light-emitting element is within the range of 300 nm to 500 nm, preferably within the range of 380 nm to 500 nm, more preferably within the range of 400 nm to 480 nm, further preferably within the range of 420 nm to 470 nm, and particularly preferably within the range of 420 nm to 460 nm. By using a light-emitting element that emits light with a peak emission wavelength within the range of 300 nm to 500 nm as the excitation light source, mixed light of light from the light-emitting element and fluorescence from the phosphor is emitted.

[0075] The light emitting element preferably uses a nitride-based semiconductor (In X Al Y Ga 1-X-Y A semiconductor light-emitting element having a wavelength N, 0≤X, 0≤Y, and X+Y≤1. Using a semiconductor light-emitting element as the excitation light source for a light-emitting device can provide a light-emitting device with high efficiency, high linearity between output and input, and high stability against mechanical shock. The full width at half maximum of the emission spectrum of the light-emitting element is preferably, for example, 30 nm or less.

[0076] A light-emitting device includes the above-mentioned silicate phosphor. In the silicate phosphor, the phosphor particles preferably have a composition represented by formula (1) above, and emit fluorescence having a peak emission wavelength in the range of 520 nm to 560 nm when irradiated with excitation light having a peak emission wavelength in the range of 300 nm to 500 nm. The light-emitting device may include: a first phosphor including the silicate phosphor, and a second phosphor having a different composition from the silicate phosphor, the second phosphor emitting fluorescence having a peak emission wavelength different from the peak emission wavelength of the first phosphor. By including the silicate phosphor and the phosphor having a different peak emission wavelength from the silicate phosphor, the light-emitting device can have a desired color temperature and emit mixed color light with wide color reproduction or high color rendering properties.

[0077] The first phosphor can be included in a wavelength conversion member that covers an excitation light source, for example, to form a light-emitting device. In this light-emitting device, a light-emitting element serving as the excitation light source is covered by the wavelength conversion member containing the first phosphor. A portion of the light emitted from the light-emitting element serving as the excitation light source is absorbed by the first phosphor, resulting in fluorescence emission having a peak wavelength different from the peak wavelength of light emitted by the light-emitting element.

[0078] The content of the first phosphor contained in the light-emitting device is not particularly limited. For example, the content of the first phosphor can be more than 1 part by mass and less than 200 parts by mass, preferably more than 2 parts by mass and less than 180 parts by mass, relative to 100 parts by mass of the resin constituting the wavelength conversion component. The resin contained in the wavelength conversion component can be a thermosetting resin, a thermoplastic resin, or a UV curing resin. As the resin, specifically, there can be mentioned: acrylic resin, carbonate resin, polysulfone resin, epoxy resin, urethane resin, esterified resin, silicone resin, styrene resin, vinyl resin, cyclic olefin resin and other olefin resins, (meth) acrylic resin, etc., and it can also contain at least one selected from them. In this specification, (meth) acrylic resin refers to a resin containing a (meth) acryloyl group, and refers to a resin containing at least one selected from methacrylate and acrylate. As the resin, it is preferably at least one selected from acrylic resin, silicone resin and epoxy resin. The resin contained in the wavelength conversion component can be a single type or a combination of two or more types.

[0079] In addition to the resin and phosphor, the wavelength conversion component may further include fillers, light-diffusing materials, and the like. For example, the inclusion of fillers and light-diffusing materials can mitigate the directivity of light from the excitation light source and increase the viewing angle. Examples of fillers and light-diffusing materials include silica, titanium oxide, zinc oxide, zirconium oxide, and aluminum oxide. When the wavelength conversion component includes fillers and light-diffusing materials, the content of the fillers and light-diffusing materials can be, for example, from 1 part by mass to 20 parts by mass per 100 parts by mass of the resin contained in the wavelength conversion component.

[0080] The method for manufacturing a silicate phosphor comprises:

[0081] Prepare a raw material, which includes: a first alkali metal element A containing at least one selected from Rb and Cs 1 A first compound containing at least one second alkali metal element A selected from K, Na and Li 2 a second compound, at least one element M selected from Mg, Ca, Sr, Ba, Y and La 1 a third compound containing Li, a fourth compound containing Si, and a sixth compound containing Eu, wherein at least one compound among the first to sixth compounds is an oxide;

[0082] The first alkali metal element A contained in the first compound 1 , the second alkali metal element A contained in the second compound 2 , the element M contained in the third compound 1 , Li contained in the fourth compound, Si contained in the fifth compound, and Eu contained in the sixth compound are mixed so as to satisfy the molar ratio in the composition represented by the following formula (1) to obtain a raw material mixture; and

[0083] The raw material mixture is subjected to a first heat treatment at a first temperature within a range of 400° C. to 800° C. in a reducing atmosphere to obtain a first heat-treated product having a composition represented by the following formula (1).

[0084] A 1 1-w-x A 2 w M 1 x (Li3SiO4):Eu y (1)

[0085] (In the above formula (1), w, x and y satisfy 0 <w<1.0、0<x≤0.125、w+x≤1.0、0<y≤0.08。)

[0086] From the first compound to the sixth compound, each containing the first alkali metal element A can be used. 1 , the second alkali metal element A 2 Element M 1 , Li, Si and Eu oxides, hydroxides, carbonates, and hydrates can also be used. Specifically, as the first alkali metal element A 1 The first compound of the present invention includes Rb2O, RbOH, Rb2CO3, Cs2CO3, etc. As the first compound containing the second alkali metal element A 2 The second compound of M includes K2O, KOH, K2CO3, Na2O, NaOH, Na2CO3, Li2O, LiOH, Li2CO3, etc. 1 The third compound includes MgO, Mg(OH)2, MgCO3, CaO, Ca(OH)2, CaCO3, SrO, Sr(OH)2, SrCO3, BaO, Ba(OH)2, BaCO3, Y2O3, Y2(CO3)3, La2O3, La(OH)3, etc. The fourth compound including Li is the same as the second compound, and includes Li2O, LiOH, Li2CO3, etc. The fifth compound including Si includes SiO2. The sixth compound including Eu includes Eu2O3, Eu(OH)2, EuCO3, etc. When the second alkali metal element A 2 When Li, contains the second alkali metal element A 2 The second compound and the fourth compound containing Li may be the same compound. When the second compound and the fourth compound are the same compound containing Li, the molar ratio of Li contained in the compound is not the same as the second alkali metal element A in 1 mol of the composition represented by the above formula (1). 2 The molar ratio of Li is not the second alkali metal element A 2 The contained Li is preferably obtained by mixing the second compound and the fourth compound so as to satisfy the molar ratio of Li constituting the composition of (Li 3 SiO 4 ) in the above formula (1).

[0087] Weighing is performed so that the first alkali metal element A contained in the first compound 1 , the second alkali metal element A contained in the second compound 2 , the element M contained in the third compound 1 The first to sixth compounds are mixed so that the molar ratios of Li contained in the fourth compound, Si contained in the fifth compound, and Eu contained in the sixth compound satisfy the composition represented by the above formula (1), thereby obtaining a raw material mixture.

[0088] Weighed amounts of the first to sixth compounds are wet or dry mixed in a mixer to obtain a raw material mixture. The mixer may be a commonly used industrial pulverizer such as a ball mill, vibration mill, roller mill, or jet mill. By pulverizing the raw materials, the specific surface area can be increased to promote the reaction. The raw materials may be classified so that the specific surface area of ​​the particles of each compound is within a certain range. For classification of the raw materials, commonly used industrial wet separators such as settling tanks, hydrocyclones, and centrifugal separators may be used, or dry classifiers such as cyclones and air separators may be used.

[0089] The raw material mixture may contain a flux. When the raw material mixture contains a flux, when the raw material mixture is subjected to the first heat treatment described below, the reaction of the first to sixth compounds is accelerated, and the solid-phase reaction proceeds uniformly, thereby obtaining a first heat-treated product of the silicate phosphor with increased particle size and excellent luminescence properties. A halide can be used as a flux. When a halide is used as a flux, the temperature at which the halide liquid phase is generated is substantially equal to the temperature at which the raw material mixture is subjected to the first heat treatment described later, and the solid-phase reaction between the compounds proceeds more uniformly, thereby obtaining a first heat-treated product of the silicate phosphor with increased particle size and excellent luminescence properties. Examples of halides used as fluxes include chlorides or fluorides containing rare earth metal elements such as cerium and europium, and chlorides or fluorides containing alkali metal elements or alkaline earth metal elements. When the flux contains elements that are also included in the composition of the silicate phosphor, the molar ratio of the elements contained in the flux can be adjusted to obtain the desired silicate phosphor composition, and a solvent can be added to the raw material mixture as part of the elements that constitute the composition. Even when the flux contains elements that are also included in the composition of the silicate phosphor core particles, the flux can be further added to the raw material mixture regardless of the composition of the silicate phosphor core particles. When the raw material mixture contains a flux, in order to further promote the reaction of the first to sixth compounds, the amount of flux added is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and may be 1 part by mass or more, relative to 100 parts by mass of the raw material mixture without the flux.

[0090] The raw material mixture is subjected to a first heat treatment in a reducing atmosphere at a first temperature within a range of 400°C to 800°C to obtain a first heat-treated product having a composition represented by the above formula (1). The raw material mixture can be placed in a crucible or combustion boat container made of a material such as silicon carbide (SiC), quartz, alumina, or boron nitride (BN) and subjected to the first heat treatment in a furnace.

[0091] The first temperature for the first heat treatment is in the range of 400°C to 800°C, preferably in the range of 500°C to 780°C, and more preferably in the range of 600°C to 750°C. By performing the first heat treatment at a relatively low temperature in the range of 400°C to 800°C, a first heat-treated product of a silicate phosphor containing the first alkali metal element A can be obtained. 1 , the second alkali metal element A 2 , replace the first alkali metal element A 1 or the second alkali metal element A 2 A divalent or trivalent element M 1 , and Eu and has a composition represented by the above formula (1).

[0092] In order to obtain the first heat-treated product of the silicate phosphor having the composition represented by the above formula (1), the time for the first heat treatment is preferably more than 1 hour and less than 20 hours, more preferably more than 2 hours and less than 15 hours, and further preferably more than 3 hours and less than 12 hours.

[0093] The atmosphere for performing the first heat treatment is a reducing atmosphere. The reducing atmosphere is preferably a nitrogen atmosphere containing reducing hydrogen. In the nitrogen atmosphere containing reducing hydrogen, the nitrogen content is preferably 70 volume % or more, more preferably 80 volume % or more, and further preferably 90 volume % or more. In addition, the hydrogen content in the nitrogen atmosphere containing reducing hydrogen is preferably 1 volume % or more, more preferably 5 volume % or more, and further preferably 10 volume % or more. The atmosphere for performing the first heat treatment may also be a reducing atmosphere using solid carbon in an atmospheric atmosphere. By calcining in a reducing atmosphere with strong reducing power, the divalent Eu in the first heat-treated product of the raw material mixture can be reduced. 2+ The content ratio of divalent Eu increases. 2 + Easily oxidized to form trivalent Eu 3+ However, by subjecting the raw material mixture to the first heat treatment in a reducing atmosphere with strong reducing power, the trivalent Eu contained in the first heat-treated product 3+ Reduced to divalent Eu 2+ Therefore, divalent Eu can be obtained, which contributes to luminescence. 2+ The first heat-treated product has an increased content ratio, and the first heat-treated product can be obtained as a silicate phosphor with high luminescence intensity.

[0094] The pressure during the first heat treatment can be standard atmospheric pressure (about 0.101 MPa), or can be carried out under a pressurized atmosphere of 0.101 MPa or more and 200 MPa or less in gauge pressure. By carrying out the heat treatment under a pressurized atmosphere, the decomposition of the crystalline structure in the first heat-treated product is reduced, and a first heat-treated product of a silicate phosphor with reduced luminescence intensity can be obtained. The pressure of the atmosphere during the first heat treatment is more preferably in the range of 0.101 MPa or more and 100 MPa or less, further preferably in the range of 0.5 MPa or more and 10 MPa or less, and from the viewpoint of ease of manufacture, it is further preferably in the range of 1.0 MPa or more and 10 MPa or less.

[0095] The first heat-treated product obtained can be subjected to post-treatment after heat treatment such as pulverization, dispersion, solid-liquid separation, drying, etc. Solid-liquid separation can be carried out by methods commonly used in industry such as filtration, suction filtration, pressure filtration, centrifugation, decantation, etc. Drying can be carried out by devices commonly used in industry such as vacuum dryers, hot air heating dryers, conical dryers, rotary evaporators, etc. After obtaining the first heat-treated product, post-treatment can be carried out as needed, and the first heat-treated product after post-treatment can be used as a silicate phosphor. After obtaining the first heat-treated product, post-treatment can be carried out as needed, and the first heat-treated product after post-treatment can be subjected to a second heat treatment to obtain the second heat-treated product.

[0096] In the method for producing a silicate phosphor, the obtained first heat-treated product is preferably subjected to a second heat treatment at a second temperature in the range of 200° C. to 350° C. to obtain a second heat-treated product having a composition represented by the above formula (1).

[0097] The second temperature for the second heat treatment is preferably in the range of 200°C to 350°C, more preferably in the range of 200°C to 300°C. By performing the second heat treatment at a lower second temperature of about half the first temperature of the first heat treatment, the crystal structure can be stabilized, thereby obtaining a second heat-treated product of a silicate phosphor with high luminescence intensity. By performing the second heat treatment at a low temperature of 200°C to 350°C, the first alkali metal element A located between the tetrahedral structure of the silicate (SiO4) and lithium oxide of the silicate phosphor is stabilized. 1 A large cubic structure centered on the second alkali metal element A 2 A cubic structure centered on the first alkali metal element A 1 or the second alkali metal element A 2 The element M 1 The structure is stable and not easy to twist.

[0098] The second heat treatment may be performed in any of an atmosphere containing oxygen, an atmosphere containing nitrogen, and an atmosphere containing a rare gas. The atmosphere for performing the second heat treatment may be an air atmosphere (containing 20% ​​by volume or more of oxygen), a nitrogen atmosphere (nitrogen is 100% by volume), or an atmosphere containing a rare gas (e.g., argon (Ar) is 100% by volume).

[0099] The second heat treatment may be performed for, for example, 0.5 hours to 20 hours, 1 hour to 15 hours, or 2 hours to 12 hours. By setting the holding time to 0.5 hours to 20 hours, the crystal structure can be further stabilized.

[0100] The pressure of the atmosphere carrying out the second thermal treatment can be standard atmospheric pressure (about 0.101MPa), can be more than 0.101MPa, or can be carried out under the pressurized atmosphere of more than 0.101MPa and below 100MPa. By carrying out the second thermal treatment under the pressurized atmosphere of more than 0.101MPa and below 100MPa, it is possible to make crystalline structure stabilization. The atmospheric pressure when carrying out the second thermal treatment is with gauge pressure, more preferably more than 0.101MPa and within the scope of less than 100MPa, further preferably more than 0.5MPa and within the scope of less than 10MPa, from the viewpoint of easy manufacture, further preferably more than 1.0MPa and within the scope of less than 10MPa.

[0101] Example

[0102] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0103] The following evaluations were performed on each silicate phosphor in the Examples and Comparative Examples described below. The molar ratios of the added compositions and the evaluations for each silicate phosphor in the Examples and Comparative Examples described below are reported in Tables 1 and 2. In Table 1, the symbol "-" indicates that the numerical value did not match the item. Each silicate phosphor in Examples 1 to 11 described below had the composition represented by Formula (1) above.

[0104] Luminescence characteristics (relative luminous intensity, peak luminous wavelength λp, full width at half maximum (FWHM))

[0105] For each of the silicate phosphors of the examples and comparative examples, using a fluorescence spectrophotometer (F-4500, manufactured by Hitachi High-Tech Science Corporation), each phosphor was irradiated with excitation light having a peak emission wavelength of 450 nm, and the emission spectrum was measured at room temperature (25 °C ± 5 °C). The peak emission wavelength λp (nm), full width at half maximum (FWHM) (nm), and emission intensity at the peak emission wavelength of each phosphor were measured. The emission intensity at the peak emission wavelength of the β-sialon phosphor having a composition represented by a peak emission wavelength of 529 nm and having the formula Si 6-z Al z O z N 8-z :Eu y1 (where y1 and z satisfy 0 < y1 ≤ 1.0 and 0 < z ≤ 4.2.) was set as 100%, and the emission intensity of each silicate phosphor was expressed in the form of relative emission intensity. Figure 2 The emission spectra of the silicate phosphors of Examples 1 to 4 and the silicate phosphor of Comparative Example 1 are shown. Figure 3 The emission spectra of the silicate phosphor of Example 7 and the silicate phosphor of Comparative Example 2 are shown.

[0106] Samples for light resistance evaluation

[0107] With respect to 100 parts by mass of an acrylic resin, 50 parts by mass of each silicate phosphor of the examples and comparative examples were mixed to prepare a resin composition. The resin composition was formed into a sheet, and a barrier film having a thickness of 100 μm and a water vapor transmission rate of 0.02 g / m 2 ·day at a temperature of 40 °C and a relative humidity of 90% was disposed above and below the sheet of the resin composition to sandwich the sheet. The sheet was irradiated with ultraviolet light at room temperature to ultraviolet-cure the resin of the sheet, and a sheet-like wavelength conversion member having a thickness of 70 μm and containing each silicate phosphor of the examples and comparative examples was obtained, which was used as a sample for light resistance evaluation. The wavelength conversion member was sandwiched between two barrier films, and the total thickness of the two barrier films and the wavelength conversion member was 270 μm.

[0108] Light resistance evaluation

[0109] For each of the obtained samples, at room temperature (25 °C), each sample was placed under irradiation with excitation light having a peak emission wavelength of 450 nm and an output of 36 mW / cm 2The side of the sample irradiated with excitation light from the light-emitting element (LED) was kept irradiated with the excitation light from the light-emitting element. After 500 hours, the luminescence spectrum of each sample was measured, and the luminescence intensity at the luminescence peak wavelength was measured. Before 500 hours, the luminescence spectrum of each sample was measured when irradiated with excitation light from the light-emitting element. The ratio of the luminescence intensity at the luminescence peak wavelength after 500 hours of continuous irradiation with excitation light relative to the luminescence intensity at the luminescence peak wavelength of each sample 500 hours ago was expressed as the lumen maintenance rate (%). Figure 4 A graph showing the relationship between the irradiation time of excitation light and the lumen maintenance rate of each silicate phosphor of Examples 2 and 7 and the silicate phosphor of Comparative Example 1.

[0110] Example 1

[0111] Preparation of raw materials for the first to sixth compounds: containing the first alkali metal element A 1 The first compound Rb2CO3 contains the second alkali metal element A 2 The second compound of Na2CO3 containing element M 1 The third compound MgO, the fourth compound Li2CO3 containing Li, the fifth compound SiO2 containing Si, and the sixth compound Eu2O3 containing Eu.

[0112] The first to sixth compounds were weighed so that the molar ratio of the added elements, Rb:Na:Mg:Li:Si:Eu, was 0.75:0.23:0.02:3:1:0.04, and mixed to obtain a raw material mixture. The molar ratio of the elements contained in the first to sixth compounds in the raw material mixture satisfied the molar ratio of the composition represented by formula (1).

[0113] The raw material mixture was placed in an alumina container and subjected to a first heat treatment at 750°C for 10 hours in a reducing atmosphere of a nitrogen and hydrogen mixture (nitrogen:hydrogen volume ratio of 70:30) to obtain a first heat-treated product. The first heat-treated product was then subjected to post-treatment including pulverization, dispersion, solid-liquid separation, and drying.

[0114] Pulverization is the wet pulverization that adds the 1st heat-treated product and alumina ball in a solvent (ethanol). The 1st heat-treated product after 100 mass parts of pulverization is put into 440 mass parts of ethanol, and while stirring with a stirrer, 100 mass parts of 7 mass % hydrochloric acid aqueous solution are added dropwise during 30 minutes. After dropping hydrochloric acid aqueous solution, the mixture of the 1st heat-treated product, ethanol and hydrochloric acid aqueous solution is stirred for 30 minutes and dispersed. Thereafter, the 1st heat-treated product is solid-liquid separated, cleaned with ethanol, dried 2 days under a nitrogen atmosphere (N2:100 volume %) at 25 ℃, obtained the 1st heat-treated product of the after-treatment of pulverization, dispersion, solid-liquid separation, drying, and the 1st heat-treated product obtained is used as the silicate phosphor of Example 1.

[0115] Example 2

[0116] Use the same 1st to 6th compounds as in Example 1, weigh the 1st to 6th compounds so that the molar ratio of the added composition of each element Rb:Na:Mg:Li:Si:Eu is 0.75:0.21:0.04:3:1:0.04, and mix them to obtain a raw material mixture. Use this mixture and operate in the same way as in Example 1 except this to obtain a first heat-treated product. The obtained first heat-treated product is used as the silicate phosphor of Example 2.

[0117] Example 3

[0118] Use the same 1st to 6th compounds as in Example 1, weigh the 1st to 6th compounds so that the molar ratio of the added composition of each element Rb:Na:Mg:Li:Si:Eu is 0.75:0.17:0.08:3:1:0.04, and mix them to obtain a raw material mixture. Use this mixture and operate in the same way as in Example 1 except this to obtain a first heat-treated product. The obtained first heat-treated product is used as the silicate phosphor of Example 3.

[0119] Example 4

[0120] Use the same 1st to 6th compounds as in Example 1, weigh the 1st to 6th compounds so that the molar ratio of the added composition of each element Rb:Na:Mg:Li:Si:Eu is 0.75:0.125:0.125:3:1:0.04, and mix them to obtain a raw material mixture. Use this mixture and operate in the same way as in Example 1 except this to obtain a first heat-treated product. The obtained first heat-treated product is used as the silicate phosphor of Example 4.

[0121] Comparative Example 1

[0122] Do not use the containing element M 1The third compound is prepared, and the first, second, fourth to sixth compounds are the same as those in Example 1. The first, second, fourth to sixth compounds are weighed so that the molar ratio of the added elements Rb:Na:Mg:Li:Si:Eu is 0.75:0.25:0:3:1:0.04, and they are mixed to obtain a raw material mixture. The mixture is used in the same manner as in Example 1 except for this to obtain a first heat-treated product. The obtained first heat-treated product is used as the silicate phosphor of Comparative Example 1.

[0123] [Table 1]

[0124]

[0125] When irradiated with excitation light having a peak wavelength of 450 nm from a light-emitting element, the silicate phosphors of Examples 1 to 4 emit green fluorescence having a peak wavelength in the range of 520 nm to 560 nm, and the peak wavelength λp is 530 nm. Compared to the β-sialon phosphor that emits green fluorescence with a peak wavelength of 529 nm, the silicate phosphors of Examples 1 to 4 have a narrow peak in the full width at half maximum in the emission spectrum. Figure 2 As shown, in the luminescence spectrum, the silicate phosphors of Examples 1 to 3 have luminescence peaks that substantially overlap.

[0126] The silicate phosphors of Examples 1 to 4 have the following compositions: In the composition represented by the above formula (1), the element M 1 , and the first alkali metal element A 1 or the second alkali metal element A 2 A portion of is replaced by a divalent element M 1 The silicate phosphors of Examples 1 to 4 can reduce the amount of divalent Eu that contributes to luminescence in order to achieve charge balance. 2+ Towards trivalent Eu 3+ The change of 36mW / cm 2 After the excitation light of high power is turned on, the lumen maintenance rate is over 60%, and the decrease in luminous intensity is reduced.

[0127] Compared with the silicate phosphors of Examples 1 to 4, the silicate phosphor of Comparative Example 1 does not contain the element M. 1 , therefore, the relative luminous intensity becomes slightly higher. On the other hand, the silicate phosphor of Comparative Example 1 does not contain the element M in its composition. 1 , so it cannot reduce the divalent Eu that contributes to luminescence 2+ Towards trivalent Eu 3+The change of 36mW / cm 2 When the excitation light power is increased, the lumen maintenance rate drops to less than 60%.

[0128] Example 5

[0129] Using the containing element M 1 The third compound CaCO3 is prepared. In addition, the first compound, the second compound, and the fourth to sixth compounds that are the same as those in Example 1 are used, and the first to sixth compounds are weighed so that the molar ratio of the added composition of each element Rb:Na:Ca:Li:Si:Eu is 0.75:0.23:0.02:3:1:0.04. A raw material mixture obtained by mixing them is used, and the same operation as in Example 1 is performed except for this, to obtain a first heat-treated product, and the obtained first heat-treated product is used as the silicate phosphor of Example 5.

[0130] Example 6

[0131] Using the containing element M 1 The third compound La2O3 is prepared. In addition, the first compound, the second compound, and the fourth to sixth compounds that are the same as those in Example 1 are used, and the first to sixth compounds are weighed so that the molar ratio of the added composition of each element Rb:Na:La:Li:Si:Eu is 0.75:0.23:0.02:3:1:0.04. A raw material mixture obtained by mixing them is used, and the same operation as in Example 1 is performed except for this, to obtain a first heat-treated product, and the obtained first heat-treated product is used as the silicate phosphor of Example 6.

[0132] Example 7

[0133] The same first to sixth compounds as in Example 1 were weighed so that the molar ratio of the additive composition of the respective elements, Rb:Na:Mg:Li:Si:Eu, was 0.75:0.21:0.04:3:1:0.04. Using the raw material mixture obtained by mixing these, the same procedures as in Example 1 were followed to obtain a first heat-treated product. The obtained first heat-treated product was subjected to a second heat treatment at 300°C for 10 hours in a nitrogen atmosphere (N2: 100% by volume) to obtain a second heat-treated product. This second heat-treated product was used as the silicate phosphor of Example 7.

[0134] Example 8

[0135] The same first to sixth compounds as in Example 1 were weighed so that the molar ratio of the additive composition of the respective elements, Rb:Na:Mg:Li:Si:Eu, was 0.75:0.21:0.04:3:1:0.04. The raw material mixture obtained by mixing these was subjected to the same procedures as in Example 1 to obtain a first heat-treated product. The obtained first heat-treated product was subjected to a second heat treatment at 250°C for 10 hours in a nitrogen atmosphere (N2: 100% by volume) to obtain a second heat-treated product. This second heat-treated product was used as the silicate phosphor of Example 8.

[0136] Example 9

[0137] The same first to sixth compounds as in Example 1 were weighed so that the molar ratio of the additive composition of the respective elements, Rb:Na:Mg:Li:Si:Eu, was 0.75:0.21:0.04:3:1:0.04. Using the raw material mixture obtained by mixing these, the same procedures as in Example 1 were followed to obtain a first heat-treated product. The obtained first heat-treated product was subjected to a second heat treatment at 200°C for 10 hours in a nitrogen atmosphere (N2: 100% by volume) to obtain a second heat-treated product. This second heat-treated product was used as the silicate phosphor of Example 9.

[0138] Example 10

[0139] The same first to sixth compounds as in Example 1 were weighed so that the molar ratio of the additive composition of the respective elements, Rb:Na:Mg:Li:Si:Eu, was 0.75:0.17:0.08:3:1:0.02. Using the raw material mixture obtained by mixing these, the same operation as in Example 1 was performed to obtain a first heat-treated product. The obtained first heat-treated product was subjected to a second heat treatment at 250°C for 10 hours in a nitrogen atmosphere (N2: 100% by volume) to obtain a second heat-treated product. This second heat-treated product was used as the silicate phosphor of Example 10.

[0140] Example 11

[0141] The same first to sixth compounds as in Example 1 were weighed so that the molar ratio of the additive composition of the respective elements, Rb:Na:Mg:Li:Si:Eu, was 0.75:0.17:0.08:3:1:0.01. Using the raw material mixture obtained by mixing these, the same procedures as in Example 1 were followed to obtain a first heat-treated product. The obtained first heat-treated product was subjected to a second heat treatment at 250°C for 10 hours in a nitrogen atmosphere (N2: 100% by volume) to obtain a second heat-treated product. This second heat-treated product was used as the silicate phosphor of Example 11.

[0142] Comparative Example 2

[0143] The first heat-treated product obtained from Comparative Example 1 was subjected to a second heat treatment at 150°C for 10 hours in a nitrogen atmosphere (N2: 100 volume %) to obtain a second heat-treated product, which was used as the silicate phosphor of Comparative Example 2.

[0144] [Table 2]

[0145]

[0146] When the silicate phosphors of Examples 5-11 were irradiated with excitation light having a peak emission wavelength of 450 nm from a light-emitting element, they emitted green fluorescence with a peak emission wavelength λp of 527 nm to 530 nm, with the peak wavelength ranging from 520 nm to 560 nm. Even after undergoing the second heat treatment, the silicate phosphors of Examples 5-11 exhibited a narrower, sharper full-width-at-half-maximum emission spectrum than the β-sialon phosphor described in Table 1, which emits green fluorescence with a peak emission wavelength of 529 nm. When the silicate phosphors of Examples are used in backlight light-emitting devices, the range of color reproducibility can be expanded.

[0147] like Figure 3 As shown, the silicate phosphor of Example 7 obtained by the second heat treatment has a light emission peak wavelength in the range of 520 nm to 560 nm when irradiated with excitation light having a light emission peak wavelength of 450 nm from a light emitting element.

[0148] The silicate phosphors of Examples 5 to 11 have the following compositions: the composition represented by the above formula (1) contains the element M 1 , and the first alkali metal element A 1 or the second alkali metal element A 2 A portion of is replaced by a divalent or trivalent element M 1 The silicate phosphors of Examples 5 to 11 can reduce the amount of divalent Eu that contributes to luminescence in order to achieve charge balance. 2+ Towards trivalent Eu 3+ The change of 36mW / cm 2 After the excitation light of the power is increased, the luminous flux maintenance rate is more than 60%, and the decrease in luminous intensity is reduced. Since the silicate phosphors of Examples 7 to 11 have undergone the second heat treatment at a temperature of 200°C or higher and 350°C or lower, the luminous flux of the phosphors is 36 mW / cm2 under irradiation for 500 hours. 2Even after the excitation light of high power, the phosphors of Examples 7 to 11 have a light flux maintenance rate of more than 90%, and are very good in light resistance. It is speculated that the silicate phosphors of Examples 7 to 11 undergo a second heat treatment at a temperature of 200°C or higher and 350°C or lower, and the first alkali metal element A 1 Or the second alkali metal element A 2 A portion of is replaced by a divalent or trivalent element M 1 The crystal structure of the silicate phosphor is more stable, which can further reduce the divalent Eu that contributes to luminescence. 2+ Towards trivalent Eu 3+ The change in the luminous intensity further reduces the decrease in luminous intensity, and has a high lumen maintenance rate. In the composition represented by the above formula (1), the silicate phosphors of Examples 10 and 11 have a lumen maintenance rate exceeding 90% and are more excellent in light resistance, although the molar ratio of Eu as an activating element is smaller than that of the silicate phosphor of Example 3 shown in Table 1 above.

[0149] The silicate phosphor of Comparative Example 2 does not contain element M in its composition. 1 The temperature of the second heat treatment is 150℃, which is lower than 200℃, so the divalent Eu that contributes to luminescence cannot be reduced. 2+ Towards trivalent Eu 3+ The change of 36mW / cm after 500 hours of irradiation 2 After the excitation light power is increased, the lumen maintenance rate is reduced to 34.4%.

[0150] Figure 4 Graph showing the relationship between the irradiation time of the excitation light and the lumen maintenance rate of each silicate phosphor of Examples 2 and 7 and the silicate phosphor of Comparative Example 1. Figure 4 As shown, each silicate phosphor of Examples 2 and 7 has the following composition: In the composition represented by the above formula (1), the element M 1 , the first alkali metal element A 1 or the second alkali metal element A 2 A portion of is replaced by a divalent or trivalent element M 1 , which can reduce the divalent Eu that contributes to luminescence in order to achieve charge balance. 2+ Towards trivalent Eu 3+ Even after 500 hours of continuous irradiation with excitation light, the silicate phosphor of Example 7, which had undergone the second heat treatment, maintained a very high luminous flux maintenance rate of over 98% after 500 hours of continuous irradiation with excitation light, demonstrating even better light resistance.

[0151] The following thermoluminescence spectra were measured for each of the silicate phosphors of Examples 3 and 7, and the silicate phosphor of Comparative Example 1. Table 3 shows the ratio (TLa / TLp) of the average thermoluminescence intensity (TLa) within the range of 560 K to 580 K relative to the maximum thermoluminescence intensity (TLp) within the range of 240 K to 350 K, in the thermoluminescence spectra obtained by measuring the thermoluminescence intensities of the silicate phosphors of Examples 3 and 7, and the silicate phosphor of Comparative Example 1.

[0152] Thermoluminescence spectroscopy

[0153] For each silicate phosphor in the Examples and Comparative Examples, thermoluminescence spectra were measured by irradiating the sample with a xenon lamp light source for 5 minutes at 200K using an excitation light source with a bandpass filter (313nm, half-value width 40nm). After the excitation light was cut off, the photomultiplier tube, which passed a bandpass filter (550nm, half-value width 40nm), was used as a detector. The changes in emission intensity were recorded while the temperature was increased. To release pre-trapped electrons, the sample was heated to 600K before measurement. The measurement was performed at a heating rate of 30K / min. Figure 5 3 and 4 show the thermoluminescent spectra of the silicate phosphors of Examples 3 and 7 and the silicate phosphor of Comparative Example 1 measured at a heating rate of 30 K / min.

[0154] [Table 3]

[0155]

[0156] In the thermoluminescence spectra (luminescence curves) of the silicate phosphors of Examples 3 and 7 obtained by thermoluminescence measurement, the ratio TLa / TLp of the average value TLa of the TL intensity in the range of 560K to 580K to the maximum TL intensity value TLp in the range of 240K to 350K is less than 0.25, the TL intensity in the range above 550K is suppressed, the lumen maintenance rate after continuous irradiation with excitation light increases to more than 60%, and the decrease in luminescence intensity is reduced.

[0157] like Figure 5 As shown in the thermoluminescence spectra (luminescence curves) measured by thermoluminescence, the TL intensity of each silicate phosphor of Examples 3 and 7 decreases to a low level in the range above 550K. This indicates that there are few defects in the crystal structure that can capture electrons, and electrons in the defect levels are difficult to be captured, so it is difficult for them to transfer to Eu. 2+ Supplying electrons to Eu 3+ Therefore, even if the excitation light is continuously irradiated, the decrease in luminescence intensity is reduced.

[0158] The silicate phosphor of Comparative Example 1 does not contain the element M in the composition of the silicate phosphor. 1Therefore, in the thermoluminescence spectrum (luminescence curve) obtained by thermoluminescence measurement, the ratio TLa / TLp (the average TL intensity TLa within the range of 560K to 580K) to the maximum TL intensity TLp within the range of 240K to 350K) exceeded 0.25 and reached 1.08. The silicate phosphor of Comparative Example 1 has a high TL intensity within the range of 550K and above, resulting in a lumen maintenance rate of less than 60% after continuous irradiation with excitation light, resulting in a low luminous intensity.

[0159] like Figure 5 As shown, in the thermoluminescence spectrum (luminescence curve) of each silicate phosphor of Comparative Example 1 measured by thermoluminescence, the TL intensity in the range above 550K becomes very high from 520K, and there are many defects in the crystal structure that capture electrons. The electrons captured in the defect energy level are transferred to Eu 2+ Donates electrons and easily changes to Eu 3+ , so the luminous intensity decreases when the excitation light is continuously irradiated.

[0160] For each of the silicate phosphors of Examples 1 to 11 and the silicate phosphors of Comparative Examples 1 and 2, X-ray diffraction patterns were measured as follows. Figure 6 X-ray diffraction patterns of the silicate phosphors of Examples and Comparative Examples are shown. Figure 7 The X-ray diffraction patterns of the silicate phosphors of Examples 1 to 4 are enlarged in the portion where the diffraction angle 2θ (°) is 37° to 37.8°.

[0161] X-ray diffraction pattern

[0162] For each silicate phosphor of the examples and comparative examples, a sample-level multifunctional X-ray diffraction apparatus (Ultima IV, manufactured by Rigaku Corporation) with an X-ray source of CuKα line ( The X-ray diffraction pattern was measured at a tube voltage of 40 kV and a tube current of 40 mA.

[0163] In such Figure 6 In the X-ray diffraction patterns shown, the silicate phosphors of Examples 1 to 11 and the silicate phosphors of Comparative Examples 1 to 2 have peaks at almost the same diffraction angle 2θ (°). In the composition represented by the above formula (1), even if the first alkali metal element A is added, 1 or the second alkali metal element A 2 A portion of is replaced by a divalent or trivalent element M 1 , and the crystal structure has not changed significantly.

[0164] In such Figure 7 In the X-ray diffraction diagram of the enlarged part shown, when the molar ratio of the element M in the silicate phosphor of Examples 1 to 4 is added,1 When the diffraction angle 2θ (°) is increased, a small peak can be confirmed at a position of 37.4°. It is speculated that in the silicate phosphor having the composition represented by the above formula (1), the element M 1 When the molar ratio of becomes larger, the crystal structure changes slightly.

[0165] Embodiments of the present disclosure include the following silicate phosphors, light-emitting devices, and methods for manufacturing silicate phosphors.

[0166] [Project 1]

[0167] A silicate phosphor having a composition represented by the following formula (1):

[0168] A 1 1-w-x A 2 w M 1 x(Li3SiO4):Eu y (1)

[0169] In the formula (1), A 1 is at least one first alkali metal element selected from Rb and Cs, A 2 is at least one second alkali metal element selected from K, Na and Li, M 1 is at least one element selected from Mg, Ca, Sr, Ba, Y and La, and w, x and y are respectively 0 <w<1.0、0<x≤0.125、w+x≤1.0、0<y≤0.08。

[0170] [Project 2]

[0171] The silicate phosphor according to item 1, wherein

[0172] In the formula (1), w, x, and y satisfy 0.1≤w≤0.24, 0.01≤x≤0.125, and 0.01≤y≤0.08.

[0173] [Item 3]

[0174] The silicate phosphor according to item 1 or 2, wherein

[0175] In the above formula (1), x satisfies 0.02≤x≤0.125.

[0176] [Item 4]

[0177] The silicate phosphor according to any one of items 1 to 3, wherein

[0178] In the formula (1), A 1 Contains Rb, A 2Contains Na.

[0179] [Item 5]

[0180] The silicate phosphor according to any one of items 1 to 3, wherein

[0181] In the formula (1), A 1 Rb, A 2 For that.

[0182] [Item 6]

[0183] The silicate phosphor according to any one of items 1 to 5, wherein

[0184] In the formula (1), M 1 Contains Mg.

[0185] [Item 7]

[0186] The silicate phosphor according to any one of claims 1 to 5, wherein

[0187] In the formula (1), M 1 For Mg.

[0188] [Item 8]

[0189] The silicate phosphor according to any one of items 1 to 7, wherein

[0190] In the thermoluminescence spectrum obtained by measuring the thermoluminescence intensity, the average value of the thermoluminescence intensity TL in the range of 560K and above and 580K is a The maximum thermoluminescence intensity TL in the range of 240K to 350K p TL a / TL p 0.25 or less.

[0191] [Item 9]

[0192] A light-emitting device comprising:

[0193] The silicate phosphor according to any one of items 1 to 8, and

[0194] A light-emitting element having a light emission peak wavelength within a range of 300 nm to 500 nm inclusive and irradiating the silicate phosphor with excitation light.

[0195] [Item 10]

[0196] A method for manufacturing a silicate phosphor, the method comprising:

[0197] Prepare a raw material, which includes: a first alkali metal element A containing at least one selected from Rb and Cs 1 A first compound containing at least one second alkali metal element A selected from K, Na and Li 2 The second compound contains at least one element M selected from Mg, Ca, Sr, Ba, Y and La 1 a third compound containing Li, a fourth compound containing Si, and a sixth compound containing Eu, wherein at least one compound among the first to sixth compounds is an oxide;

[0198] The first alkali metal element A contained in the first compound 1 The second alkali metal element A contained in the second compound 2 , the element M contained in the third compound 1 , Li contained in the fourth compound, Si contained in the fifth compound, and Eu contained in the sixth compound are mixed in a molar ratio satisfying the composition represented by the following formula (1) to obtain a raw material mixture; and

[0199] The raw material mixture is subjected to a first heat treatment at a first temperature in a range of 400° C. to 800° C. in a reducing atmosphere to obtain a first heat-treated product having a composition represented by the following formula (1).

[0200] A 1 1-w-x A 2 w M 1 x (Li3SiO4):Eu y (1)

[0201] In the above formula (1), w, x and y satisfy 0 <w<1.0、0<x≤0.125、w+x≤1.0、0<y≤0.08。

[0202] [Item 11]

[0203] The method for producing a silicate phosphor according to item 10, the method comprising:

[0204] The first heat-treated product is subjected to a second heat treatment at a second temperature within a range of 200° C. to 350° C. to obtain a second heat-treated product having a composition represented by the formula (1).

[0205] Industrial Applicability

[0206] The silicate phosphor disclosed herein can be used as a phosphor contained in a wavelength conversion component of a light-emitting device. A light-emitting device containing the silicate phosphor can be suitably used in applicable light-emitting devices such as lighting light sources, LED displays, backlight light sources for liquid crystals, annunciators, illuminated switches, light sources for projectors, various sensors, and various indicators.

Claims

1. A silicate phosphor having a composition represented by the following formula (1): A 1 1-w-x A 2 w M 1 x(Li3SiO4):Eu y (1) In the formula (1), A 1 is a first alkali metal element of at least one selected from Rb and Cs, A 2 is at least one second alkali metal element selected from K, Na and Li, M 1 is at least one element selected from Mg, Ca, Sr, Ba, Y and La, and w, x and y are respectively 0 <w<1.0、0<x≤0.125、w+x≤1.0、0<y≤0.08。 2. The silicate phosphor according to claim 1, wherein In the formula (1), w, x, and y satisfy 0.1≤w≤0.24, 0.01≤x≤0.125, and 0.01≤y≤0.

08.

3. The silicate phosphor according to claim 1, wherein In the above formula (1), x satisfies 0.02≤x≤0.

125.

4. The silicate phosphor according to claim 1, wherein In the formula (1), A 1 Contains Rb, A 2 Contains Na.

5. The silicate phosphor according to claim 1, wherein In the formula (1), A 1 Rb, A 2 For that.

6. The silicate phosphor according to claim 1, wherein In the formula (1), M 1 Contains Mg.

7. The silicate phosphor according to claim 1, wherein In the formula (1), M 1 For Mg.

8. The silicate phosphor according to claim 1, wherein In the thermoluminescence spectrum obtained by measuring the thermoluminescence intensity, the average value of the thermoluminescence intensity TL in the range of 560K or higher and 580K or lower is a The maximum thermoluminescence intensity TL in the range of 240K to 350K p TL a / TL p 0.25 or less.

9. A light-emitting device comprising: The silicate phosphor according to any one of claims 1 to 8; and A light-emitting element having a light emission peak wavelength in the range of 300 nm to 500 nm, and irradiating the silicate phosphor with excitation light.

10. A method for producing a silicate phosphor, the method comprising: Prepare a raw material comprising: a first alkali metal element A containing at least one selected from Rb and Cs; 1 a first compound containing at least one selected from K, Na and Li; and a second alkali metal element A 2 The second compound contains at least one element M selected from Mg, Ca, Sr, Ba, Y and La 1 a third compound containing Li, a fourth compound containing Si, and a sixth compound containing Eu, wherein at least one compound among the first to sixth compounds is an oxide; The first alkali metal element A contained in the first compound 1 The second alkali metal element A contained in the second compound 2 , the element M contained in the third compound 1 , mixing the first to sixth compounds so that Li contained in the fourth compound, Si contained in the fifth compound, and Eu contained in the sixth compound satisfy the molar ratio of the composition represented by the following formula (1) to obtain a raw material mixture; and The raw material mixture is subjected to a first heat treatment at a first temperature in a range of 400° C. to 800° C. in a reducing atmosphere to obtain a first heat-treated product having a composition represented by the following formula (1). A 1 1-w-x A 2 w M 1 x (Li3SiO4):Eu y (1) In the above formula (1), w, x and y satisfy 0 <w<1.0、0<x≤0.125、w+x≤1.0、0<y≤0.08。 11. The method for producing a silicate phosphor according to claim 10, comprising: The first heat-treated product is subjected to a second heat treatment at a second temperature within a range of 200° C. to 350° C. to obtain a second heat-treated product having a composition represented by the formula (1).

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