JP2005068412A - Green light-emitting phosphor and light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a green light-emitting phosphor capable of emitting a green color, by being excited by long-wavelength ultraviolet light or visible light having a wavelength of 350-500 nm, and having high emission intensity, and to provide a light-emitting device given by using the green light-emitting phosphor. <P>SOLUTION: This green light-emitting phosphor emits light by being excited by the light having the wavelength of 350-500 nm, wherein the phosphor contains Tb<SP>3+</SP>ions in a high concentration as a light-emitting ion and does not cause concentration quenching. The green light-emitting phosphor has the high emission intensity in the wavelength range of 350-500 nm, especially, a range of 350-385 nm corresponding to a short-wavelength ultraviolet region or a range of 475-500 nm corresponding to a visible light region of a blue color to a blue-green color, and develops good green light emission which fits visibility and has never existed yet, especially, the green light emission in a wavelength range near 555 nm which is believed to be good for the visibility, more especially, a wavelength range in front and behind of 545 nm. The light-emitting device which has high luminance and emits the green color, a white color, or a neutral color is obtained by using a light-emitting device which is given by using the green light-emitting phosphor and displays the green color, a light-emitting device which is given by using the green light-emitting phosphor together with a red light-emitting phosphor and a blue light-emitting phosphor and displays the white color or the neutral color, or a light-emitting device which is given by using the green light-emitting phosphor together with a yellow light-emitting phosphor and displays the white color or the neutral color. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a green light-emitting phosphor that emits green light when excited by long-wavelength ultraviolet light or visible light of 350 to 500 nm, and a light-emitting device using the green light-emitting phosphor.

  A light emitting diode (LED: Light Emitting Diode) is a semiconductor light emitting element that emits light, and converts electrical energy into ultraviolet light, visible light, infrared light, and the like. For example, as a device using visible light, there is a semiconductor light emitting element formed of a light emitting material such as GaP, GaAsP, or GaAlAs, and an LED lamp in which these are sealed with a transparent resin or the like is widely used. In addition, a display-type LED lamp in which a light emitting material is fixed on the upper surface of a printed circuit board or a metal lead and sealed with a transparent resin case shaped like a number or letter is also frequently used.

  In addition, since the light emitting diode is a semiconductor element, it has a long life, high reliability, and when used as a light source, the replacement work can be reduced. Therefore, portable communication devices, personal computer peripheral devices, OA devices, home use It is widely used as a component of various display devices such as electric devices, audio devices, various switches, backlight light sources, and bulletin boards. In addition, LED lamps are attracting attention as a backlight illumination light source for in-vehicle device displays, and are used for backlight illumination in displays such as meters, heater control panels, and audio, especially in the white or blue-green region. There is a need for LED lamps that emit light.

Such an LED lamp can be obtained by changing the color of the light emitted from the LED by including various phosphor powders in the transparent resin that seals the semiconductor light emitting element. Depending on the application, it is possible to obtain a wide range of colors in the visible light region from blue to red. However, phosphors conventionally used in fluorescent lamps (three-wavelength fluorescent lamps) and the like, for example, Tb ³ represented by LaPO ₄ : Ce ³⁺ , Tb ³⁺ , CeMgAl ₁₁ O ₁₉ : Tb ^{3+ and the} like. ⁺ green-emitting phosphor which emits light by _⁵ D ₄ → ⁷ F ⁵ transition ions, although giving good luminous in the ultraviolet region of the short wavelength is used in fluorescent lamps, the wavelength utilized in the high-intensity LED lamps 350 Sufficient light emission was not obtained with respect to 500 nm long wavelength ultraviolet rays or visible rays.

  Recently, demands of consumers for the colors of the various display devices are increasing, and the display devices are required to have a performance capable of reproducing subtle hues more precisely. In addition, a single LED lamp emits white and various intermediate colors. There is a strong demand to be able to make it happen. Therefore, by applying various phosphors of red, green, and blue to the surface of the semiconductor light emitting element of the LED lamp, or by incorporating the various phosphors into the sealing material, coating material, etc. of the LED lamp, 1 Attempts have also been made to configure white LED and various intermediate colors with a single LED lamp.

  However, when a white emission color is obtained using long-wavelength ultraviolet light or visible light having a wavelength of 350 to 500 nm, for example, even when the above-described green light emitting phosphor is used as the green light emitting phosphor, the obtained green light visibility is obtained. Therefore, white light with high luminance cannot be obtained.

Therefore, various phosphors that emit light when excited by long-wavelength ultraviolet light or visible light have been studied. For example, BaMg ₂ Al ₁₆ O ₂₇ is used as a green light-emitting phosphor excited by long-wavelength ultraviolet light or short-wavelength visible light (350 to 420 nm). : Eu, Mn, Zn ₂ GeO ₄ : Mn, and the like, and the emission color is blue, BaMg ₂ Al ₁₆ O ₂₇ : Eu, (Sr, Ca, Ba) ₅ (PO ₄ ) ₃ Cl: Eu, light emission Red Y ₂ O ₂ S: Eu, La ₂ O ₂ S: Eu, 3.5MgO · 0.5MgF ₂ · GeO ₂ : Mn, and the like have also been developed. By using these phosphors as appropriate, it is becoming possible to obtain a wide range of emission colors. However, for practical use of LED lamps that give high-intensity white light, the emission intensity is higher and the visibility is high. It is necessary to develop a phosphor that emits good light. In particular, in terms of visibility, the green light obtained with the above-described green light-emitting phosphor is considerably deviated from 555 nm, which is considered to have good visibility, and this has been a factor that hinders high brightness.

On the other hand, if an LED that emits blue to blue-green visible light (430 to 500 nm) and a phosphor such as YAG: Ce ³⁺ that emits yellow light at this wavelength are used, an LED lamp that emits white light. However, since there was no phosphor that gave effective green emission in this wavelength region, the emission color could not be changed freely.

  The prior art document information relating to the present invention includes the following.

JP 2002-60747 A Japanese Patent Laid-Open No. 2002-226846 Keiichi Nishimura and 1 other, “Fluorescent Lamps and Environmental Conservation”, Journal of the Illuminating Society of Japan, Illuminating Society of Japan, 1997, Vol. 81, No. 9, p. 834-839

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a green light-emitting phosphor exhibiting high emission intensity at a wavelength of 350 to 500 nm and a light-emitting device using the green light-emitting phosphor.

As a result of intensive studies to solve the above problems, the present inventor is a green light-emitting phosphor that emits light when excited by light having a wavelength of 350 to 500 nm, and has a high concentration of Tb ³⁺ ions as light-emitting ions. A green light-emitting phosphor that contains and does not cause concentration quenching, in particular, a green light-emitting phosphor that emits light when excited by light having a wavelength of 350 to 500 nm, and has the following composition formula (1)
ATb _x Ln _(1-x) M ₂ O ₈ (1)
(In the formula, A is at least one selected from Li, Na, K and Ag, Ln is at least one selected from rare earth elements including Y (excluding Tb), and M is at least one selected from Mo and W. , X is a positive number satisfying 0.4 ≦ x ≦ 1.)
Even though the green light-emitting phosphor represented by Tb ³⁺ ion, which is a luminescent ion, contains a high concentration, it emits green light stably and with high emission intensity without causing concentration quenching, The present inventors have found that the present invention exhibits excellent green light emission unprecedented in visual sensitivity at a wavelength of 350 to 385 nm which is a short wavelength ultraviolet region or a wavelength of 475 to 500 nm which is a visible light region of blue to blue green.

  Further, a light emitting device that displays green using the green light emitting phosphor, a red light emitting phosphor, a light emitting device that displays white or an intermediate color in combination with a blue light emitting phosphor, or a white light The light-emitting device that displays intermediate colors has become a light-emitting device that emits light with high luminance, and has been found to be able to display subtle shades more precisely and with good reproducibility, leading to the present invention.

That is, the present invention
[1] A green light-emitting phosphor that emits light when excited by light having a wavelength of 350 to 500 nm, contains a high concentration of Tb ³⁺ ions as light-emitting ions, and does not cause concentration quenching. Luminous phosphor,
[2] It contains Y ³⁺ ion, Dy ³⁺ ion, La ³⁺ ion, Gd ³⁺ ion or Lu ³⁺ ion as a sensitizer for Tb ³⁺ ion which is a luminescent ion [1 ] The green light emitting phosphor described in the above,
[3] A green-emitting phosphor that emits light when excited by light having a wavelength of 350 to 500 nm, and has the following composition formula (1)
ATb _x Ln _(1-x) M ₂ O ₈ (1)
(In the formula, A is at least one selected from Li, Na, K and Ag, Ln is at least one selected from rare earth elements including Y (excluding Tb), and M is at least one selected from Mo and W. , X is a positive number satisfying 0.4 ≦ x ≦ 1.)
The green-emitting phosphor according to [1], which is represented by:
[4] The green-emitting phosphor according to [3], wherein Ln in the composition formula (1) is Y, Dy, La, Gd, or Lu,
[5] The green light-emitting phosphor according to any one of [1] to [4], wherein the green-emitting phosphor is an average particle diameter of 10 to 200 μm,
[6] The green light-emitting phosphor according to any one of [1] to [5], which is a phosphor for a light-emitting diode,
[7] A light-emitting device in which a semiconductor light-emitting element that emits light having a wavelength of 350 to 500 nm is sealed in a sealing material, wherein the sealing material is any one of [1] to [5]. A light emitting device characterized in that a green light emitting phosphor is dispersed,
[8] A light-emitting device in which a semiconductor light-emitting element that emits light having a wavelength of 350 to 500 nm is sealed in a sealing material, and the light-emitting device emits light from the semiconductor light-emitting element. 5], a light emitting device comprising a fluorescent layer containing the green light emitting phosphor according to any one of
[9] The light-emitting device according to [8], wherein the phosphor layer is provided on the semiconductor light-emitting element or a sealing material, and [10] the green phosphor emits the green light-emitting phosphor, resin, rubber The light-emitting device according to [9] is provided by being dispersed in an elastomer or glass.

  The green light-emitting phosphor of the present invention has a high emission intensity at a wavelength of 350 to 500 nm, particularly 350 to 385 nm which is a short wavelength ultraviolet region, or 475 to 500 nm which is a blue to blue-green visible light region, and has a visibility. The green light emission of the conventional green light emission, particularly the green light emission near the wavelength of 555 nm, particularly the wavelength around 545 nm, which is considered to have good visibility, is displayed using the green light emitting phosphor. High brightness and green when used in light emitting devices, red light emitting phosphors, light emitting devices that display white or neutral colors in combination with blue light emitting phosphors, or light emitting devices that display white or intermediate colors in combination with yellow light emitting phosphors Alternatively, a light-emitting device that emits white or intermediate color can be obtained.

The present invention will be described in detail below.
The green light-emitting phosphor of the present invention is a green light-emitting phosphor that emits light when excited by light having a wavelength of 350 to 500 nm, contains Tb ³⁺ ions as light-emitting ions at a high concentration, and does not cause concentration quenching. It is. In this case, it is preferable that Y ³⁺ ion, Dy ³⁺ ion, La ³⁺ ion, Gd ³⁺ ion or Lu ³⁺ ion is contained as a sensitizer for Tb ³⁺ ion which is a luminescent ion.

In general phosphors, the concentration of luminescent ions (activator) is added by several mol% with respect to the base crystal. At concentrations higher than that, [1] cross relaxation occurs due to resonance transfer between the activators, and excitation energy [2] Excitation migration due to resonance transmission between activators occurs, which promotes the transition and extinction of excitation to the crystal surface and non-luminescent center, [3] It is known that concentration quenching occurs due to reasons such as agglomeration or formation of ion pairs that change to non-luminescent centers or killer (fluorescence inhibitors). In contrast, the green light-emitting phosphor of the present invention does not cause concentration quenching even though it contains Tb ³⁺ ions at a high concentration far exceeding the concentration at which concentration quenching occurs. It emits green light with a high emission intensity.

As such a green light-emitting phosphor, for example, the following composition formula (1)
ATb _x Ln _(1-x) M ₂ O ₈ (1)
(In the formula, A is at least one selected from Li, Na, K and Ag, Ln is at least one selected from rare earth elements including Y (excluding Tb), and M is at least one selected from Mo and W. , X is a positive number satisfying 0.4 ≦ x ≦ 1.)
The thing represented by is mentioned. The green light emitting phosphor represented by the composition formula (1) has a wavelength of 350 to 500 nm, particularly a wavelength of 350 to 385 nm which is a short wavelength ultraviolet region, or 475 which is a blue to blue-green visible light region. At a wavelength of 500 nm, the emission intensity is high, and good green light emission suitable for visual sensitivity is exhibited.

The green light-emitting phosphor of the present invention may contain a rare earth element represented by Ln together with Tb (including Y, excluding Tb; the same shall apply hereinafter). Formula (2),
ATbM ₂ O ₈ (2)
(A and M are the same as the above composition formula (1))
And a structure in which a part of a Tb (Tb ion) site in a metal oxide crystal represented by the above is substituted with a rare earth element (rare earth element ion) represented by Ln. By coexisting Tb and a rare earth element in the crystal, a green light emitting phosphor exhibiting particularly high intensity green light emission can be obtained. As the rare earth element to coexist with Tb, Y (yttrium), Dy (dysprosium), La (lanthanum), Gd (gadolinium) or Lu (lutetium) is particularly preferable. Coexisting Tb and Y, Dy, La, Gd or Lu, ie, Y ³⁺ ion, Dy ³⁺ ion, La ³⁺ ion, Gd as a sensitizer for Tb ³⁺ ion which is a luminescent ion Those containing ³⁺ ions or Lu ³⁺ ions have high emission intensity at a wavelength of 475 to 500 nm in the blue to blue-green visible light region, and exhibit good green light emission suitable for visual sensitivity. Even at a wavelength of 350 to 385 nm in the wavelength ultraviolet region, the emission intensity is high, and good green light emission suitable for visual sensitivity, especially green light emission around wavelength 555 nm, especially around 545 nm, where visual sensitivity is good, It is given with high brightness.

  The ratio of Tb to the rare earth element represented by Ln is a positive number (Tb ion where x in the composition formula (1) satisfies 0.4 ≦ x ≦ 1, preferably 0.4 ≦ x <1. To a ratio of the substitution rate R of rare earth elements represented by Ln to ions with 0 ≦ R ≦ 60 at%, preferably 0 <R ≦ 60 at%.

  When Y is included as the rare earth element represented by Ln, x in the composition formula (1) is a positive number satisfying 0.8 ≦ x <1, particularly 0.95 ≦ x <1 (from Tb ion to Ln. It is preferable that the substitution ratio R of rare earth elements to ions is such that 0 <R ≦ 20 at%, particularly 0 <R ≦ 5 at%.

  When Dy is included as the rare earth element represented by Ln, x in the composition formula (1) is a positive number satisfying 0.8 ≦ x <1, particularly 0.95 ≦ x <1 (from Tb ion to Ln It is preferable that the substitution rate R of the rare earth element represented by ions is such that 0 <R ≦ 20 at%, particularly 0 <R ≦ 5 at%.

  When La is contained as the rare earth element represented by Ln, x in the composition formula (1) is 0.4 ≦ x <1, particularly 0.5 ≦ x ≦ 0.9, especially 0.6 ≦ x ≦. A positive number satisfying 0.8 (replacement ratio R from Tb ion to rare earth element ion represented by Ln is 0 <R ≦ 60 at%, particularly 10 ≦ R ≦ 50 at%, especially 20 ≦ R ≦ 40 at%) The ratio is preferably

  When Gd is included as the rare earth element represented by Ln, x in the composition formula (1) is a positive number satisfying 0.5 ≦ x <1, particularly 0.95 ≦ x <1 (from Tb ion to Ln It is preferable that the substitution rate R of the rare earth element represented by ions is such that 0 <R ≦ 50 at%, particularly 0 <R ≦ 5 at%.

  When Lu is contained as the rare earth element represented by Ln, x in the composition formula (1) is a positive number satisfying 0.97 ≦ x <1, particularly 0.99 ≦ x <1 (from Tb ion to Ln It is preferable that the substitution rate R of the rare earth element represented by ions is such that 0 <R ≦ 3 at%, particularly 0 <R ≦ 1 at%.

  When x in the composition formula (1) satisfies these ranges (that is, the substitution rate R satisfies these ranges), this green light-emitting phosphor emits good green that matches the visibility with high intensity. To be. On the other hand, when the value of x is less than the above range (when the substitution rate R exceeds the above range), sufficient green light emission may not be obtained.

  On the other hand, A is at least one selected from Li, Na, K and Ag, and Li and Na are particularly preferable.

Further, those containing both Li and Na as A in the composition formula (1), that is, those in which a part of the sites of Li ⁺ ions are substituted with Na ⁺ ions are also suitable. In this case, the ratio of Li to Na is such that Li is 100%>Li> 0%, preferably 85% ≧ Li ≧ 40%, more preferably 70% ≧ Li ≧ 50%, and Na is 0% <Na < It is preferable that 100%, preferably 15% ≦ Na ≦ 60%, more preferably 30% ≦ Na ≦ 50% (where Li + Na = 100%).

In the present invention, the green light emitting phosphor is used as a raw material such as an oxide or carbonate containing an element constituting the green light emitting phosphor, such as Li ₂ CO ₃ , Na ₂ CO ₃ , Tb ₄ O ₇ , Y ₂ O. ₃ , Dy ₂ O ₃ , La ₂ O ₃ , Gd ₂ O ₃ , Lu ₂ O ₃ , W ₂ O _3, etc. are stoichiometrically so as to have a predetermined composition represented by the above composition formula (1) after firing. The raw material mixture obtained by mixing in a ratio and mixing with a ball mill or the like is fired, and can be obtained by washing, pulverizing, and sieving as necessary.

  The firing method can be a conventionally known method used for the production of a metal oxide used as a phosphor, and is not particularly limited. For example, the raw material mixture is placed in an alumina crucible, A method of producing by firing in a firing furnace such as a furnace may be employed. In this case, the firing temperature is preferably 800 to 1,000 ° C., particularly preferably 850 to 900 ° C., and the firing time is preferably 30 minutes to 48 hours, particularly preferably 2 to 12 hours.

  Furthermore, in the present invention, the element represented by A in the green light emitting phosphor represented by the above composition formula (1), that is, a part of Li, Na, K or Ag is a coactivator. Those substituted with at least one selected from the group consisting of Rb, Cs, Mg, Ca, Sr and Ba added as are also suitable. The substitution rate in this case is less than 0.5 (atomic ratio), preferably 0.3 in terms of the ratio of the total amount of Rb, Cs, Mg, Ca, Sr and Ba to the total amount of A (Li, Na, K and Ag). (Atomic ratio) or less, more preferably 0.2 (atomic ratio) or less, particularly preferably 0.1 (atomic ratio) or less. In this case, the lower limit of the substitution rate is not particularly limited, but is preferably 0.01 (atomic ratio) or more, more preferably 0.05 (atomic ratio) or more.

  The green light-emitting phosphor of the present invention is preferably particles having an average particle diameter of 10 to 200 μm, particularly 75 to 150 μm. By using a particle having an average particle diameter in the above range, particularly high intensity fluorescence can be obtained. When the average particle diameter exceeds 200 μm, there is a possibility that uniform dispersion of the phosphor cannot be obtained, and when other phosphors are used in combination, color unevenness may occur. On the other hand, if the average particle size is less than 10 μm, the strength may be lowered.

Next, the light emitting device of the present invention will be described.
First, the 1st aspect of the light-emitting device of this invention is demonstrated. The light-emitting device according to the first aspect is a light-emitting device in which a semiconductor light-emitting element that emits light having a wavelength of 350 to 500 nm is sealed in a sealing material. A green light emitting phosphor is dispersed.

  Specifically, as shown in FIG. 1, leads 1 and 2, a semiconductor light emitting element 3 that emits light having a wavelength of 350 to 500 nm, and a thin lead wire 4 that electrically connects the semiconductor light emitting element 3 and the lead 2. Of a so-called shell-type light emitting diode having a structure sealed in a shell shape with a sealing material 5 or a pair of box-shaped light emitter housing members 6 having an open top surface as shown in FIG. The leads 1 and 2 are extended to the outside of the light emitter housing member 6, and the semiconductor light emitting element 3 and the lead thin wires 4 and 4 that emit light having a wavelength of 350 to 500 nm are housed inside the light emitter housing member 6. Is obtained by dispersing the green light-emitting phosphor of the present invention in a sealing material 5 such as a so-called chip-type light emitting diode having a structure in which the inside of the light-emitting body housing member 6 is sealed with a sealing material 5. Can be mentioned.

In this case, if only the above-described green light-emitting phosphor of the present invention is dispersed in the sealing material 5, a light-emitting device that emits green with high luminance suitable for visual sensitivity is obtained, and Y ₂ O ₂ S: Eu, La ₂ O ₂ S: Eu, 3.5MgO.0.5MgF ₂ .GeO ₂ : Mn and other red light emitting phosphors, BaMg ₂ Al ₁₆ O ₂₇ : Eu, (Sr, Ca, Ba) ₅ (PO ₄ ) ₃ Cl When dispersed together with a blue light-emitting phosphor such as Eu, a light-emitting device that emits white or intermediate color with high luminance suitable for visual sensitivity is obtained. Further, when a blue to blue-green light emitting element is used as the semiconductor light emitting element 3 and the green light emitting phosphor of the present invention is used together with a yellow light emitting phosphor such as YAG: Ce ³⁺ , a high-intensity white color suitable for visual sensitivity is obtained. Alternatively, a light emitting device that emits an intermediate color is obtained. In any of these light emitting devices, a green light emitting phosphor other than the green light emitting phosphor of the present invention, for example, BaMg ₂ Al ₁₆ O ₂₇ : Eu, Mn, Zn ₂ GeO ₄ : Mn, or the like is added as the green light emitting phosphor. It is possible.

  This light-emitting device can be manufactured by mixing a phosphor with a sealing material such as resin, rubber, elastomer, or glass when sealing a semiconductor light-emitting element or the like. In particular, when a plurality of types of phosphors are used, the specific gravity of the phosphors is different, so that a phosphor having a large specific gravity may settle faster than a phosphor having a small specific gravity, thereby causing color unevenness. Therefore, in the light emitting device of the present invention, the phosphor is sealed by a method of mixing a high viscosity material such as a silicone rubber composition or a silicone resin composition whose viscosity is adjusted with a thixotropy adjusting agent and curing the mixture. It is preferable to disperse in the material. In addition to the phosphor described above as a color tone conversion material, pigments, dyes, pseudo pigments, and the like may be added to the sealing material.

  Next, a second aspect of the light emitting device of the present invention will be described. The light-emitting device of the second aspect is a light-emitting device in which a semiconductor light-emitting element that emits light having a wavelength of 350 to 500 nm is sealed in a sealing material, and the light emitted from the semiconductor light-emitting element. A fluorescent layer containing the above-described green light emitting phosphor of the present invention is provided on the road.

  As such a thing, what provided the fluorescent layer containing the green light emission fluorescent substance of this invention on a semiconductor light emitting element or a sealing material, for example is mentioned, Specifically, as shown in FIG. The lead 1 and 2, the semiconductor light emitting device 3 that emits light having a wavelength of 350 to 500 nm, and the lead thin wire 4 that electrically connects the semiconductor light emitting device 3 and the lead 2 are sealed in a shell shape with a sealing material 5. A so-called shell-type light-emitting diode semiconductor light-emitting element 3 having a fluorescent layer 7 sealed with the semiconductor light-emitting element 3 and the like, and a box-shaped light-emitting body with an open top as shown in FIG. A pair of leads 1 and 2 are extended from the inner bottom of the housing member 6 to the outside of the light emitter housing member 6, and the semiconductor light emitting element 3 and leads that emit light having a wavelength of 350 to 500 nm inside the light emitter housing member 6. Accommodates fine wires 4 and 4 Subsequently, a phosphor layer 7 is provided on the semiconductor light emitting element 3 of a so-called chip-type light emitting diode having a structure in which the inside of the light emitter housing member 6 is sealed with the sealing material 5 and sealed together with the semiconductor light emitting element 3 and the like. 5, a bullet-type light emitting diode as shown in FIG. 5 provided with a fluorescent layer 7 so as to cover the sealing material 5, a chip type light emitting diode as shown in FIG. The thing which provided the fluorescent layer 7 on the sealing material 5 of this is mentioned. The configuration other than the fluorescent layer in FIGS. 5 and 6 is the same as the configuration shown in FIGS.

  Further, the fluorescent layer 7 is not limited to the so-called transmission type in which the fluorescent layer is provided in the light emitting diode or adjacent to the light emitting diode as described above, but the fluorescent layer 7 is separated from the light emitting diode 8 as shown in FIG. There is also a so-called reflection type light-emitting device that is provided at a position and reflects light emitted from the fluorescent layer by the reflection plate 9. Further, the fluorescent layer of the light emitting device in which the fluorescent layer is provided on the sealing material as shown in FIGS. 5 and 6 can be further sealed with the sealing material.

In this case, if only the above-described green light-emitting phosphor of the present invention is dispersed in the fluorescent layer 7, a light-emitting device that emits high-brightness green light suitable for visual sensitivity is obtained, and Y ₂ O ₂ S: Eu, La _{2 is obtained.} O ₂ S: Eu, 3.5MgO.0.5MgF ₂ .GeO ₂ : red light emitting phosphor such as Mn, BaMg ₂ Al ₁₆ O ₂₇ : Eu, (Sr, Ca, Ba) ₅ (PO ₄ ) ₃ Cl: When dispersed together with a blue-emitting phosphor such as Eu, a light-emitting device that emits a high-luminance white or intermediate color suitable for visibility. Further, when a blue to blue-green light emitting element is used as the semiconductor light emitting element 3 and the green light emitting phosphor of the present invention is used together with a yellow light emitting phosphor such as YAG: Ce ³⁺ , a high-intensity white color suitable for visual sensitivity is obtained. Alternatively, a light-emitting device that emits an intermediate color is obtained. In any of these light emitting devices, a green light emitting phosphor other than the green light emitting phosphor of the present invention, for example, BaMg ₂ Al ₁₆ O ₂₇ : Eu, Mn, Zn ₂ GeO ₄ : Mn, or the like is added as the green light emitting phosphor. It is possible.

  In addition, when providing a fluorescent layer on a semiconductor light-emitting device, the phosphor may be used as it is or may be mixed with a binder. In this case, as shown in FIGS. 3 and 4, the fluorescent layer is sealed in a sealing material together with the semiconductor light emitting element.

  On the other hand, when the fluorescent layer is provided on the sealing material, it is preferable to use the green light-emitting phosphor dispersed in a light-transmitting resin, rubber, elastomer or glass, particularly silicone resin or silicone rubber. In particular, when a plurality of types of phosphors are dispersed in the phosphor layer, as in the case of dispersing the green light-emitting phosphor of the present invention in the sealing material described above, a silicone rubber composition and a silicone resin whose viscosity is adjusted with a thixotropic modifier It is preferable to disperse in the phosphor layer by a method of mixing with a composition or the like and curing it. The fluorescent layer may be a single layer obtained by mixing phosphors, or may be a laminate of phosphors divided into several layers. In addition to the phosphor described above as a color tone conversion material, pigments, dyes, pseudo pigments, and the like may be added to the fluorescent layer.

If a green light emitting phosphor in which the light emitting ion represented by the above composition formula (1) is a Tb ³⁺ ion is used as the green light emitting phosphor used in the light emitting device of the present invention, the light emission peak is close to 555 nm, which is the peak of visual sensitivity. Therefore, the luminance of the light-emitting device can be increased, and when displaying white or intermediate colors, a delicate hue can be displayed more precisely and with good reproducibility.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to the following Example.

[Example 1]
As shown in Table 1, as the phosphor constituting raw material, 3.9056 g of WO ₃ powder, 1.5587 g of Tb ₄ O ₇ powder and 0.3112 g of Li ₂ CO ₃ powder were weighed, and these were uniformly mixed with a ball mill. The raw material mixture was obtained by mixing.

Next, the obtained raw material mixture was put in an alumina crucible and fired at a temperature of 900 ° C. for 6 hours. The obtained fired product is thoroughly washed with pure water to remove unnecessary soluble components, then finely pulverized by a ball mill, sieved (opening 53 μm), and green having a composition represented by LiTbW ₂ O _8. A luminescent phosphor was obtained.

  With respect to this green light-emitting phosphor, emission intensity at each excitation wavelength was measured with a small spectrofluorometer FP-750 (manufactured by JASCO Corporation) under excitation at 350 nm, 370 nm, 380 nm and 490 nm. The results are shown in Tables 1 and 2 and FIG. Moreover, the excitation spectrum of this green light-emitting phosphor is shown in FIG.

[Example 2, Comparative Examples 1-3]
The amount of Tb ₄ O ₇ powder was as shown in Table 1, and the Y ₂ O ₃ powder was added in the amount shown in Table 1, and the green light-emitting phosphor (LiTb _0.8 Y _{0.2 was} obtained in the same manner as in Example 1. W ₂ O ₈ (Example 2), LiTb _0.6 Y _0.4 W ₂ O ₈ (Comparative Example 1), LiTb _0.4 Y _0.6 W ₂ O ₈ (Comparative Example 2), LiTb _0.2 Y _0.8 W ₂ O ₈ (Comparative Example 3) )), And the emission intensity was measured in the same manner as in Example 1. The emission intensity was determined as a relative intensity with the emission intensity of the green light emitting phosphor obtained in Example 1 as 100. The results are shown in Table 1. Moreover, the excitation spectrum of these green light-emitting phosphors is shown in FIG.

[Examples 3 to 7]
Except that the amount of Tb ₄ O ₇ powder was as shown in Table 2 and that Dy ₂ O ₃ powder was added in the amount shown in Table 2, a green light emitting phosphor (LiTb _0.99 Dy _{0.01) was} prepared in the same manner as in Example 1. W ₂ O ₈ (Example 3), LiTb _0.97 Dy _0.03 W ₂ O ₈ (Example 4), LiTb _0.95 Dy _0.05 W ₂ O ₈ (Example 5), LiTb _0.90 Dy _0.10 W ₂ O ₈ (Example 6) ), LiTb _0.80 Dy _0.20 W ₂ O ₈ (Example 7)) was obtained, and the emission intensity was measured in the same manner as in Example 1. The emission intensity was determined as a relative intensity with the emission intensity of a commercially available green light emitting phosphor ZnS: Cu, Au, Al (manufactured by Phosphor Tech) as 100. The results are shown in Table 2 and FIG. Further, the excitation spectrum of the green light emitting phosphor obtained in Example 5 is shown in FIG. 10, and the emission spectrum obtained with the excitation light of 380 nm is shown in FIG. 11, respectively. The commercially available green light emitting phosphor ZnS: Cu, Au, Al The results are shown together with the results of (Phosphor Tech).

[Examples 8 to 12]
The amount of Tb ₄ O ₇ powder was as shown in Table 3, and La ₂ O ₃ powder was added in the amount shown in Table 3 in the same manner as in Example 1, except that the green light-emitting phosphor (LiTb _0.95 La _0.05 W ₂ O ₈ (Example 8), LiTb _0.85 La _0.15 W ₂ O ₈ (Example 9), LiTb _0.7 La _0.3 W ₂ O ₈ (Example 10), LiTb _0.4 La _0.6 W ₂ O ₈ (Example 11) ), LiTb _0.1 La _0.9 W ₂ O ₈ (Example 12)) was obtained, and the emission intensity was measured in the same manner as in Example 1. The emission intensity was determined as a relative intensity with the emission intensity of the green light emitting phosphor obtained in Example 1 as 100. The results are shown in Table 3.

[Examples 13 to 20]
The amount of Li ₂ CO ₃ powder is set as shown in Table 4, and a green light emitting phosphor (Li _0.95 Na _0.05 was added in the same manner as in Example 1 except that Na ₂ CO ₃ powder was added in the amount shown in Table 4. TbW ₂ O ₈ (Example 13), Li _0.85 Na _0.15 TbW ₂ O ₈ (Example 14), Li _0.75 Na _0.25 TbW ₂ O ₈ (Example 15), Li _0.7 Na _0.3 TbW ₂ O ₈ (Example 16) ), Li _0.6 Na _0.4 TbW ₂ O ₈ (Example 17), Li _0.5 Na _0.5 TbW ₂ O ₈ (Example 18), Li _0.4 Na _0.6 TbW ₂ O ₈ (Example 19), NaTbW ₂ O ₈ (Example) Example 20)) was obtained and the emission intensity was measured in the same manner as in Example 1. The emission intensity was determined as a relative intensity with the emission intensity of the green light emitting phosphor obtained in Example 1 as 100. The results are shown in Table 4. Moreover, the graph which plotted the emitted light intensity by the excitation light of 380 nm of the green light emission fluorescent substance of Example 1 and 13-20 with respect to the substitution rate of Na in FIG.

[Examples 21 to 24]
The amount of Tb ₄ O ₇ powder was as shown in Table 5, and Gd ₂ O ₃ powder was further added in the amount shown in Table 5 in the same manner as in Example 1, except that the green-emitting phosphor (LiTb _0.95 Gd _0.05 W ₂ O ₈ (Example 21), LiTb _0.9 Gd _0.1 W ₂ O ₈ (Example 22), LiTb _0.7 Gd _0.3 W ₂ O ₈ (Example 23), LiTb _0.5 Gd _0.5 W ₂ O ₈ (Example 24) )), And the emission intensity was measured in the same manner as in Example 1. The emission intensity was determined as a relative intensity with the emission intensity of the green light emitting phosphor obtained in Example 1 as 100. The results are shown in Table 5.

[Example 25, Comparative Examples 4 to 6]
The amount of Tb ₄ O ₇ powder is set as shown in Table 6, and Lu ₂ O ₃ powder was added in the amount shown in Table 6 in the same manner as in Example 1, except that the green light-emitting phosphor (LiTb _0.97 Lu _0.03 W ₂ O ₈ (Example 25), LiTb _0.95 Lu _0.05 W ₂ O ₈ (Comparative Example 4), LiTb _0.9 Lu _0.1 W ₂ O ₈ (Comparative Example 5), LiTb _0.5 Lu _0.5 W ₂ O ₈ (Comparative Example 6) )), And the emission intensity was measured in the same manner as in Example 1. The emission intensity was determined as a relative intensity with the emission intensity of the green light emitting phosphor obtained in Example 1 as 100. The results are shown in Table 6.

[Examples 26 to 29]
As phosphor constituent materials, 77.2800 g of WO ₃ powder, 31.1542 g of Tb ₄ O ₇ powder, 4.3091 g of Li ₂ CO ₃ powder and 2.6490 g of Na ₂ CO ₃ powder were weighed and ball milled. Were mixed uniformly to obtain a raw material mixture.

Next, the obtained raw material mixture was put into an alumina crucible and fired at a temperature of 900 ° C. for 12 hours. The obtained fired product is sufficiently washed with pure water to remove unnecessary soluble components, and then pulverized and sieved to obtain an average particle size of 15.5 μm (Example 26), 75.2 μm (implemented). Example 27), a green light emitting phosphor having a composition represented by Li _0.7 Na _0.3 TbW ₂ O ₈ of 130.4 μm (Example 28) and 188.8 μm (Example 29) was obtained.

  With respect to this green light-emitting phosphor, emission intensity at each excitation wavelength was measured by reflected light with a small spectrofluorometer FP-750 (manufactured by JASCO Corporation) under excitation with 350 nm, 370 nm, 380 nm and 490 nm. The emission intensity was determined as a relative intensity with the emission intensity of a green light emitting phosphor having an average particle diameter of 15.5 μm (Example 26) as 100. The results are shown in Table 7. From this result, it can be seen that the larger the average particle size, the higher the emission intensity.

  Next, for each of the green light emitting phosphors (Examples 26 to 29), 50 parts by mass of the green light emitting phosphor of Example 26 and 90 parts by mass of the green light emitting phosphor of Example 27 with respect to 100 parts by mass of silicone rubber. Part of the green light-emitting phosphor of Example 28 and 150 parts by weight of the green light-emitting phosphor of Example 29 were dispersed, and a 0.6 mm thick silicone rubber sheet was produced. In this case, the blending amount of the green light emitting phosphor is adjusted so that the obtained silicone rubber sheets have almost the same intensity of transmitted light of 385 nm from the near ultraviolet LED having an emission peak of 385 nm.

  This sheet was placed in front of the emission direction of a near-ultraviolet LED having an emission peak of 385 nm, and the transmitted light transmitted through the sheet and the emission spectrum of the sheet were measured using a spectral radiance meter PR-704 (manufactured by Photo Research). A graph plotting the green light emission peak intensity at a wavelength of 545 nm with respect to the particle diameter of the green light emitting phosphor used is shown in FIG.

It is a figure which shows an example of the optical apparatus of this invention, and is sectional drawing which shows the light-emitting device which disperse | distributed the green light emission fluorescent substance of this invention in the sealing material of a bullet-type light emitting diode. It is a figure which shows an example of the optical apparatus of this invention, and is sectional drawing which shows the light-emitting device which disperse | distributed the green light emission fluorescent substance of this invention to the sealing material of a chip-type light emitting diode. It is a figure which shows an example of the optical apparatus of this invention, and is sectional drawing which shows the light-emitting device which provided the fluorescent layer containing the green light emission fluorescent substance of this invention on the semiconductor light-emitting device of a bullet-type light emitting diode. It is a figure which shows an example of the optical apparatus of this invention, and is sectional drawing which shows the light-emitting device which provided the fluorescent layer containing the green light emission fluorescent substance of this invention on the semiconductor light emitting element of a chip-type light emitting diode. It is a figure which shows an example of the optical apparatus of this invention, and is sectional drawing which shows the light-emitting device which provided the fluorescent layer containing the green light emission fluorescent substance of this invention on the sealing material of a bullet-type light emitting diode. It is a figure which shows an example of the optical apparatus of this invention, and is sectional drawing which shows the light-emitting device which provided the fluorescent layer containing the green light emission fluorescent substance of this invention on the sealing material of a chip-type light emitting diode. It is a figure which shows an example of the optical apparatus of this invention, and is sectional drawing which shows the light-emitting device which reflects the light emitted from this fluorescent layer while providing a fluorescent layer in the position spaced apart from a light emitting diode. It is an excitation spectrum of the green light emission fluorescent substance of Examples 1, 2 and Comparative Examples 1-3. It is the graph which plotted the emitted light intensity by the excitation light of 350 nm, 370 nm, 380 nm, and 490 nm of the green light emission fluorescent substance of Example 1, 3-7 with respect to the substitution rate of Dy. It is the excitation spectrum of the green light emission fluorescent substance of Example 5, and a commercial item (ZnS: Cu, Au, Al). It is the emission spectrum by the excitation light of 380 nm of the green light emission fluorescent substance of Example 5, and a commercial item (ZnS: Cu, Au, Al). It is the graph which plotted the emitted light intensity by the excitation light of 380 nm of the green light emission fluorescent substance of Example 1, 13-20 with respect to the substitution rate of Na. It is the graph which plotted the green light emission peak intensity of wavelength 545nm with respect to the particle diameter of the green light emission fluorescent substance of Examples 26-29.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Lead 3 Semiconductor light-emitting device 4 Lead thin wire 5 Sealing material 6 Light emitter housing member 7 Fluorescent layer 8 Light emitting diode 9 Reflecting plate

Claims (10)

A green light-emitting phosphor which emits light when excited by light having a wavelength of 350 to 500 nm, which contains Tb ³⁺ ions as a light-emitting ion at a high concentration and does not cause concentration quenching . The sensitizing agent for Tb ³⁺ ions which are luminescent ions contains Y ³⁺ ions, Dy ³⁺ ions, La ³⁺ ions, Gd ³⁺ ions or Lu ³⁺ ions. Green light emitting phosphor. A green-emitting phosphor that emits light when excited by light having a wavelength of 350 to 500 nm, and has the following composition formula (1)
ATb _x Ln _(1-x) M ₂ O ₈ (1)
(In the formula, A is at least one selected from Li, Na, K and Ag, Ln is at least one selected from rare earth elements including Y (excluding Tb), and M is at least one selected from Mo and W. , X is a positive number satisfying 0.4 ≦ x ≦ 1.)
The green light-emitting phosphor according to claim 1, wherein   The green light-emitting phosphor according to claim 3, wherein Ln in the composition formula (1) is Y, Dy, La, Gd, or Lu.   The green light-emitting phosphor according to any one of claims 1 to 4, wherein the green particle phosphor has an average particle diameter of 10 to 200 µm.   6. The green light-emitting phosphor according to claim 1, wherein the green light-emitting phosphor is a light-emitting diode phosphor.   6. A light emitting device in which a semiconductor light emitting element that emits light having a wavelength of 350 to 500 nm is sealed in a sealing material, and the green light emitting fluorescence according to claim 1, wherein the sealing material is a light emitting device. A light emitting device in which a body is dispersed.   6. A light-emitting device in which a semiconductor light-emitting element that emits light having a wavelength of 350 to 500 nm is sealed in a sealing material, and the light-emitting device emits light from the semiconductor light-emitting element. A light-emitting device comprising a fluorescent layer containing the green-emitting phosphor according to item 1.   The light emitting device according to claim 8, wherein the fluorescent layer is provided on the semiconductor light emitting element or the sealing material. 10. The light emitting device according to claim 9, wherein the fluorescent layer is formed by dispersing the green light emitting phosphor in resin, rubber, elastomer or glass.

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