JP6029095B2 - UV light-excited yellow light-emitting material, method for producing the same, and light-emitting device - Google Patents

Description

  The present invention relates to a UV light-excited yellow light-emitting material, a manufacturing method thereof, and a light-emitting device.

In recent years, with increasing demand for lighting applications, LED (Light Emitting Diode) is becoming brighter.
A high-intensity LED emits light with high light intensity, and releases a large amount of heat associated with a large current. Each constituent member of the LED is exposed to intense light for a long period of time and is disposed at a high temperature, and thus it is necessary to have high light resistance and high heat resistance.

Typical white light emitting devices (hereinafter also referred to as white LEDs) are roughly classified into the following three types (see Non-Patent Document 1).
The first type is a white LED having a red light emitting element, a green light emitting element, and a blue light emitting element in one package.
This type does not require a binder (binder) such as an epoxy resin in one package, and can be composed of only a light emitting element, so that it can have high light resistance and high heat resistance. However, there is a problem that it is difficult to adjust the luminance and color tone of the three color light emitting elements, the circuit configuration is complicated, and the manufacturing cost is increased.

In the second type, an ultraviolet (hereinafter, also referred to as UV) light emitting element in one package and a binder (binder) such as an epoxy resin covering the light emitting element, an ultraviolet light excited red phosphor, an ultraviolet light excited green fluorescence. And a white LED in which an ultraviolet light-excited blue phosphor is dispersed.
The third type is a white light-emitting element in which a blue light-excited red phosphor and a blue light-excited green phosphor are dispersed in a blue light emitting element and a binder (binder) such as an epoxy resin covering the light emitting element in one package. LED.

Since these types use only one light emitting element in a single package, brightness and color tone adjustment is easier than in the first type, the circuit can be simplified, and manufacturing costs can be reduced. There is an advantage. In addition, there is an advantage that the adjustment range of the color temperature can be widened.
However, all of these types are configured to include a binder. When the binder is exposed to intense light for a long period of time and placed at a high temperature, the binder deteriorates, causes coloration, and reduces light transmittance. There is a problem that the luminous efficiency is lowered.
In addition, when a large current is passed and light is emitted with high luminance, not only the deterioration of the binder but also the deterioration of the characteristics of the phosphor may occur (Non-Patent Document 2).

The white LED is not limited to the configuration using the three luminescent colors, but using two luminescent colors in a complementary color relationship that pass through the white CIE chromaticity coordinates (0.33, 0.33). For example, there is a white LED in which a blue light emitting element and a granular blue light-excited yellow phosphor dispersed in a binder (binder) such as an epoxy resin are combined in one package (Patent Document) 1) Even such a white LED has a problem of a decrease in light emission efficiency due to deterioration of the binder.

Attempts have been made to use silicone resins instead of epoxy resin degradation, but no fundamental solution has been reached.

JP 2010-155891 A

“The story of high-brightness LED materials” published by Nikkan Kogyo Shimbun, p44 (2005) Materials Science and Engineering R, 71 (2010) 1-34.

The present invention relates to a UV light-excited yellow light-emitting material capable of stably emitting yellow light with high efficiency even when a large current is applied and emitting light with high brightness, a manufacturing method thereof, and high-efficiency and high-luminance light emission for a long period of time. It is an object to provide a light-emitting device capable of emitting yellow light or white light.

By repeating various experiments, this researcher newly developed a terbium, scandium, aluminum, garnet (hereinafter also referred to as Ce: TSAG) type single crystal added with cerium. This single crystal can emit yellow light stably with high brightness using UV light as excitation light. Then, by combining this single crystal with a UV light emitting element, it is conceived that a light emitting device capable of emitting yellow light or white light can be provided without using an epoxy resin, with high brightness, high efficiency, simple circuit, and low manufacturing cost. This research was completed.
The present invention has the following configuration.

(1) A UV light-excited yellow light-emitting material characterized by being a cerium-doped terbium / scandium / aluminum / garnet type single crystal.

(2) The UV light-excited yellow light-emitting material according to (1), wherein Ce element is added at a composition ratio of 5 mol% or less with respect to the total number of moles of Tb element and Ce element.
(3) UV photoexcitation according to (1) or (2), wherein a part of scandium is substituted with one or more of terbium, cerium, yttrium, lutetium, ytterbium and thulium Yellow luminescent material.

(4) The UV photoexcited yellow light-emitting material according to any one of (1) to (3), wherein a part of the scandium is substituted with a combination of +2 and +4 elements.
(5) The UV photoexcited yellow light-emitting material according to any one of (1) to (4), which is represented by the following chemical formula (I):

<Chemical formula 1>
_{((Tb 1-z Ce z} ) 1-y L y) a (M 1-x N x) b Al c O 12-w ... (I)

In the above formula (I), L represents one or more of Sc, Y, Lu, Yb, Tm, Mg, Ca, Hf or Zr, M represents Sc, and N represents Tb, Ce, Y, Lu, Yb, Tm, Mg, Ca, Hf, or Zr represents one or more of them. a, b, c, x, y, z and w are 2.5 ≦ a ≦ 3.5, 0 ≦ b ≦ 2.5, 2.5 ≦ c ≦ 5.5, 0 ≦ x ≦ 1, respectively. 0 ≦ y ≦ 0.5, 0.0001 ≦ z ≦ 0.05, and 0 ≦ w ≦ 0.5 are satisfied.

(6) A step of adjusting a powder raw material containing terbium oxide, scandium oxide, aluminum oxide, and cerium oxide, and pulling up a seed crystal from a solution obtained by heating and dissolving the powder raw material, And a step of growing a cerium-doped terbium, scandium, aluminum, and garnet type single crystal so that the composition ratio of the Ce element to the total number of moles of the Tb element and Ce element is 5 mol% or less. A method for producing a yellow luminescent material.

(7) It has the board | plate material which consists of a UV light excitation yellow luminescent material in any one of (1)-(5), and the UV light emitting element which has a light-projection surface, One surface of the said board | plate material and the said light-projection surface are The light-emitting device, wherein the UV light-excited yellow light-emitting material is disposed so as to face the UV light-emitting element.
(8) The light emitting device according to (7), wherein an emission peak wavelength of the UV light emitting element is in a range of 250 nm to 425 nm.
(9) The light-emitting device according to (7), wherein a UV light-excited yellow light-emitting material is disposed in contact with the light emission surface of the UV light-emitting element.

(10) The light-emitting device according to (7), characterized in that a UV light-excited yellow light-emitting material is disposed apart from the light-emitting surface of the UV light-emitting element.
(11) The light emitting device according to any one of (7) to (10), wherein a UV light excited blue light emitting material is disposed in contact with the UV light excited yellow light emitting material.
(12) The light emission according to (11), wherein the UV light-excited blue light-emitting material is a single crystal of Ce: R ₂ SiO ₅ (R is one or more of Lu, Y, and Gd). apparatus.

The UV light-excited yellow light-emitting material of the present invention is composed of a cerium-doped terbium, scandium, aluminum, and garnet type single crystal. Therefore, even if a large current is passed and light is emitted with high brightness by UV light excitation, it is stable and highly efficient. Yellow light can be emitted.

The method for producing a UV light-excited yellow light-emitting material of the present invention includes a step of preparing a powder raw material containing terbium oxide, scandium oxide, aluminum oxide, and cerium oxide, and a seed crystal from a solution obtained by heating and dissolving the powder raw material. And growing a cerium-added terbium / scandium / aluminum / garnet type single crystal by a melt growth method so that the composition ratio of Ce element to the total number of moles of Tb element and Ce element is 5 mol% or less. Therefore, a light emitting material capable of emitting yellow light with high brightness and high efficiency can be easily manufactured stably for a long period of time.

The light-emitting device of the present invention has a plate material made of the UV light-excited yellow light-emitting material described above and a UV light-emitting element having a light emission surface, so that one surface of the plate material faces the light emission surface, Since the UV light-excited yellow light-emitting material is arranged with respect to the UV light-emitting element, light emitted from the UV light-emitting element is incident on the UV light-excited yellow light-emitting material, and light emitted from the UV light-emitting element is emitted from the UV light-excited material. A light-emitting device capable of emitting yellow light by exciting a yellow light-emitting material and capable of emitting yellow light with high efficiency and high luminance for a long time without using a binder can be provided. In addition, the circuit can be simplified and the manufacturing cost can be reduced.

Since the light-emitting device of the present invention has a configuration in which a UV light-excited blue light-emitting material is disposed in contact with the UV light-excited yellow light-emitting material, light emitted from the UV light-emitting element is added to the UV light-excited yellow light-emitting material in addition to the UV light-excited yellow light-emitting material. A light-emitting device capable of emitting white light with high efficiency and high brightness for a long time without using an epoxy resin by exciting a blue light-emitting material can be provided. Further, the circuit can be simplified and the manufacturing cost can be reduced.

It is process drawing which shows an example of the manufacturing method of UV light excitation yellow luminescent material of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram of the light-emitting device which is the 1st Embodiment of this invention, and is sectional drawing (a) of a light-emitting device, and the light-emitting element which comprises a light-emitting device, and sectional drawing (b) of its periphery. It is a schematic diagram of the light-emitting device which concerns on the 2nd Embodiment of this invention, sectional drawing (a) of a light-emitting device, light-emitting element which comprises a light-emitting device, sectional drawing (b) of the periphery part, and light-emitting device are comprised. It is a top view (c) of a light emitting element. It is sectional drawing of the light-emitting device which is the 3rd Embodiment of this invention. It is sectional drawing of the light-emitting device which is the 4th Embodiment of this invention. It is the schematic diagram of the light-emitting device which is the 5th Embodiment of this invention, and is sectional drawing (a) of a light-emitting device, and sectional drawing (b) of the light-emitting element which comprises a light-emitting device. It is sectional drawing of the light-emitting device which is the 6th Embodiment of this invention. It is sectional drawing of the light-emitting device which is the 7th Embodiment of this invention. It is sectional drawing of the light-emitting device which is the 8th Embodiment of this invention. It is sectional drawing of the light-emitting device which is the 9th Embodiment of this invention. It is sectional drawing of the light-emitting device which is the 10th Embodiment of this invention. It is a photograph of the crystal A (Example 1 sample). It is a fluorescence spectrum of crystal A (Example 1 sample). It is an excitation spectrum of the crystal A (Example 1 sample).

[First Embodiment]
<UV light-excited yellow light-emitting material>
First, the UV light-excited yellow light-emitting material that is an embodiment of the present invention will be described.
The UV photoexcited yellow light-emitting material according to an embodiment of the present invention is a cerium-added terbium / scandium / aluminum / garnet single crystal (hereinafter also referred to as Ce: TSAG single crystal).

In the UV light-excited yellow light emitting material according to the embodiment of the present invention, it is preferable that the Ce element is added at a composition ratio of 5 mol% or less with respect to the total number of moles of the Tb element and the Ce element. Thereby, it can be set as the yellow luminescent material which has an excitation peak wavelength in the range of 250-425 nm, and has an emission peak wavelength in the range of 500-630 nm. A UV light-excited yellow light-emitting material can be combined with a UV light-emitting element having an emission peak wavelength in the range of 250 to 425 nm to provide a high-luminance and high-efficiency yellow light-emitting device.

In the UV light-excited yellow light-emitting material that is an embodiment of the present invention, a part of scandium may be substituted with any one or more of terbium, cerium, yttrium, lutetium, ytterbium, and thulium. Further, a part of the scandium may be replaced with a combination of +2 and +4 elements. Even in this case, a yellow light emitting material having an excitation peak wavelength in the range of 250 to 425 nm and an emission peak wavelength in the range of 500 to 630 nm can be obtained.

The UV light-excited yellow light-emitting material that is an embodiment of the present invention is preferably represented by the chemical formula (I) described above.
In formula (I), L represents one or more of Sc, Y, Lu, Yb, Tm, Mg, Ca, Hf, or Zr, M represents Sc, and N represents Tb, Ce, Y , Lu, Yb, Tm, Mg, Ca, Hf, or Zr represents one or more of them. a, b, c, x, y, z and w are 2.5 ≦ a ≦ 3.5, 0 ≦ b ≦ 2.5, 2.5 ≦ c ≦ 5.5, 0 ≦ x ≦ 1, respectively. 0 ≦ y ≦ 0.5, 0.0001 ≦ z ≦ 0.05, and 0 ≦ w ≦ 0.5 are satisfied.

By setting it as the said range, defects, such as a crack at the time of single crystal preparation, can be suppressed. Further, it can be a yellow light emitting material having an excitation peak wavelength in the range of 250 to 425 nm and an emission peak wavelength in the range of 500 to 630 nm, and can emit yellow light with high brightness and high efficiency by UV light excitation. it can.

  In the composition range where the composition ratio of Ce element to the total number of moles of Tb element and Ce element is 5 mol% or less, yellow light emission is obtained by adding Ce element to Tb element, and the fluorescence intensity is dramatically increased. Can be improved. On the other hand, when the composition ratio of the Ce element exceeds 5 mol%, the fluorescence intensity decreases due to concentration quenching.

<Method for producing UV light-excited yellow light-emitting material>
Next, the manufacturing method of the UV light excitation yellow luminescent material which is embodiment of this invention is demonstrated.
FIG. 1 is a process diagram showing an example of a method for producing a UV light-excited yellow light-emitting material according to an embodiment of the present invention. FIG. 1 shows a crystal pulling furnace 20 used for growing a UV light-excited yellow light-emitting material (single crystal). The crystal pulling furnace 20 mainly includes an iridium crucible 21, a ceramic cylindrical container 22 that houses the crucible 21, and a high-frequency coil 23 that is wound around the cylindrical container 22. The high frequency coil 23 generates an induced current in the crucible 21 and heats the crucible 21.

A garnet-type single crystal UV light-excited yellow light-emitting material 2 is grown by melt growth using the crystal pulling furnace 20.
First, the Tb ₄ O ₇ powder, Sc ₂ O ₃ powder, Al ₂ O ₃ powder, and CeO ₂ powder are wet-mixed at a blending rate based on the single crystal composition to be grown, and then dried to adjust the powder raw material To do. If necessary, this powder raw material may further be mixed with at least one other powder raw material. Note that dry mixing may be performed instead of wet mixing.

Next, the crucible 21 is filled with the powder raw material.
Next, a high frequency current is applied to the high frequency coil 23 to heat the crucible 21, and the powder raw material in the crucible 21 is heated from room temperature to a temperature at which the powder raw material can be dissolved. Thereby, a powder raw material is melt | dissolved and the solution 24 is obtained.

Next, a seed crystal 25 used as a rod-shaped crystal pulling axis is prepared. As the seed crystal 25, for example, a garnet-type single crystal such as yttrium, aluminum, and garnet (YAG) can be used.

Next, after bringing the tip of the seed crystal 25 into contact with the solution 24, the seed crystal 25 is pulled up at a predetermined pulling speed while rotating the seed crystal 25 at a predetermined rotation speed.
The rotation speed of the seed crystal 25 is preferably 3 to 50 rpm, more preferably 3 to 10 rpm. The pulling rate of the seed crystal 25 is preferably 0.1 to 10 mm / h, more preferably 0.5 to 3 mm / h. The seed crystal 25 is preferably pulled up in an inert gas atmosphere. As the inert gas, Ar, nitrogen, or the like can be used. Oxygen may be mixed slightly. In order to place the seed crystal 25 in an inert gas atmosphere, the inert gas may be discharged while being introduced into the sealed housing at a predetermined flow rate.

By pulling up the seed crystal 25 under the above conditions, a bulk-shaped growth crystal 26 can be obtained at the tip of the seed crystal 25.
The grown crystal 26 is a cerium-added terbium / scandium / aluminum / garnet type single crystal in which a part of Tb is substituted with Ce, and is a single crystal represented by the chemical formula (I). It is UV light excitation yellow luminescent material 2 which is.
Through the above steps, the grown crystal 26 that is the UV light-excited yellow light-emitting material 2 according to the embodiment of the present invention can be easily manufactured, and in the melt growth method, the grown crystal 26 can be easily enlarged. it can.

<Light emitting device>
Next, the light emitting device according to the first embodiment of the present invention will be described.
FIG. 2 is a schematic view of the light-emitting device 1 according to the first embodiment of the present invention. FIG. 2A is a cross-sectional view of the light-emitting device 1, and a cross-sectional view of the light-emitting element 10 constituting the light-emitting device 1 and its peripheral part. b).

As illustrated in FIG. 2A, the light emitting device 1 includes a ceramic substrate 3, a UV light emitting element (UV-LED) 10 disposed on the ceramic substrate 3, and the periphery of the UV light emitting element 10 on the ceramic substrate. And a main body 4 provided in a wall shape.
The ceramic substrate 3 is a plate-like member made of a ceramic such as Al ₂ O ₃ . On the surface, wiring portions 31 and 32 made of metal such as tungsten are patterned.
The main body 4 is a member made of a white resin formed on the ceramic substrate 3, and an opening 4A is formed at the center thereof. The opening 4A is formed in a taper shape in which the opening width gradually increases from the ceramic substrate 3 side toward the outside. The inner surface of the opening 4A is a reflecting surface 40 that reflects light from the UV light emitting element 10 toward the outside.

  As shown in FIG. 2B, the UV light emitting element 10 has its n-side electrode 15A and p-side electrode 15B mounted on the ceramic substrate 3 by the bumps 16 and 16 on the wiring portions 31 and 32 of the ceramic substrate 3, respectively. Connected.

<UV light emitting device>
As the UV light emitting element 10, a flip chip type element capable of emitting ultraviolet (UV) light having an emission peak wavelength in a range of 250 to 425 nm is used. As a material, an AlGaN-based semiconductor compound can be used.

As shown in FIG. 2B, the UV light-emitting element 10 has an n-type AlGaN: Si layer on the first main surface 11a of the element substrate 11 made of sapphire or the like via a buffer layer and an n ⁺ -GaN: Si layer. A layer 12, an AlGaN light emitting layer 13 having a multiple quantum well structure, and a p-type AlGaN: Mg layer 14 having a p ⁺ -GaN: Mg layer on the p-type electrode side are formed in this order. An n-side electrode 15A is formed on the exposed portion of the n-type AlGaN: Si layer 12, and a p-side electrode 15B is formed on the surface of the p-type AlGaN: Mg layer 14, respectively.

The light emitting layer 13 emits UV light when carriers are injected from the n-type AlGaN: Si layer 12 and the p-type AlGaN: Mg layer 14. The UV light passes through the n-type AlGaN: Si layer 12 and the element substrate 11 and is emitted from the second main surface 11 b of the element substrate 11. That is, the second main surface 11 b of the element substrate 11 is a light emitting surface of the light emitting element 10.
The light emitting surface is a surface of the UV light emitting element, and is a surface from which light is emitted from the inside of the element to the outside. In particular, this is a surface with a large amount of emitted light.

The UV light-excited yellow light-emitting material 2 according to the embodiment of the present invention is in contact with the second main surface 11b of the element substrate 11 that is the light emission surface of the UV light-emitting element 10 so as to cover the entire second main surface 11b. Is arranged.
Since the UV light-excited yellow light-emitting material 2 according to the embodiment of the present invention is a flat plate made of a single single crystal, the first surface 2 a facing the element substrate 11 is defined as the second main surface 11 b of the element substrate 11. The element substrate 11 can be directly contacted and fixed without interposing an epoxy resin therebetween. In addition, as a fixing method of UV light excitation yellow luminescent material 2, there exists a method etc. which fix using a metal piece.
Here, the single single crystal means one having a size equal to or larger than that of the second main surface 11b and being substantially regarded as one single crystal as a whole.
The first surface 2a is fixed in direct contact with the element substrate 11 without interposing an epoxy resin between the first main surface 11b of the element substrate 11 and the light from the UV light emitting element 10 is thereby fixed. The loss can be reduced and the light can be incident on the UV light-excited yellow light-emitting material 2, and the light emission efficiency of the UV light-excited yellow light-emitting material 2 can be improved.

<Light emitting mechanism of light emitting device>
In the light emitting device according to the first embodiment of the present invention shown in FIG. 1, when the UV light emitting element 10 is energized, electrons are emitted from the light emitting layer through the wiring portion 31, the n-side electrode 15 </ b> A, and the n-type AlGaN: Si layer 12. Then, holes are injected into the light emitting layer 13 through the wiring portion 32, the p-side electrode 15B, and the p-type AlGaN: Mg layer 14, and the light emitting layer 13 emits UV light. The UV light of the light emitting layer 13 passes through the n-type AlGaN: Si layer 12 and the element substrate 11 and is emitted from the second main surface 11 b of the element substrate 11, and reaches the first surface 2 a of the UV light excitation yellow light emitting material 2. Incident.

  The UV light incident from the first surface 2a excites the UV light-excited yellow light-emitting material 2 as excitation light. The UV light-excited yellow light-emitting material 2 absorbs UV light from the UV light-emitting element 10 and converts the wavelength of the absorbed UV light into yellow light having an emission peak wavelength in the range of 500 to 630 nm, for example. Thereby, the light-emitting device 1 emits yellow light.

The light-emitting device 1 according to the first embodiment of the present invention uses a flat UV light-excited yellow light-emitting material 2 made of a single single crystal, and a binder (binder) such as an epoxy resin that holds a granular phosphor. Therefore, deterioration of the binder, particularly deterioration due to irradiation with high-power excitation light, can be suppressed, and a decrease in light emission efficiency can be suppressed.
Further, as compared with the case where a large number of granular phosphors are combined, the flat UV light-excited yellow light-emitting material 2 made of a single single crystal can reduce the surface area and suppress the deterioration of characteristics due to the influence of the external environment.
In addition, since the flat UV light-excited yellow light-emitting material 2 made of a single single crystal is used, the quantum efficiency of the UV light-excited yellow light-emitting material 2 can be increased, and the light emission efficiency of the light-emitting device can be increased.
The light emitting device 1 according to the first embodiment of the present invention has a configuration using a Ce: TSAG type single crystal that is the UV light-excited yellow light emitting material 2 according to the embodiment of the present invention. Can be efficiently absorbed by the UV light-excited yellow light-emitting material 2, and yellow light can be emitted with high luminance with high quantum efficiency.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.
FIG. 3 is a schematic diagram of a light-emitting device according to a second embodiment of the present invention, and is a cross-sectional view (a) of the light-emitting device, a light-emitting element that constitutes the light-emitting device, and a cross-sectional view (b) of the periphery thereof. It is a top view (c) of the light emitting element which comprises an apparatus. (A) is sectional drawing of 1 A of light-emitting devices concerning this embodiment, (b) is sectional drawing of 10 A of UV light emitting elements which comprise the light emitting device 1A, and its periphery part, (c) is 10 A of UV light emitting elements 10A. It is a top view.

  The light emitting device 1A according to the second embodiment of the present invention has a configuration in which the light emitted from the UV light emitting element is incident on a UV light-excited yellow light emitting material made of a single single crystal and wavelength-converted. Although common to the light emitting device 1 which is a form, the configuration of the UV light emitting element and the arrangement position of the UV light-excited yellow light emitting material with respect to the UV light emitting element are different from those of the first embodiment. Hereinafter, the constituent elements of the light emitting device 1A having the same functions and configurations as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIGS. 3A and 3B, the light emitting device 1A is arranged such that the element substrate 11 of the UV light emitting element 10A faces the ceramic substrate 3 side. Further, a UV light-excited yellow light-emitting material 121 made of a single Ce: TSAG single crystal is joined to the opening 4A side of the UV light-emitting element 10A. Further, as the UV light-excited yellow light-emitting material 121, the same composition as that described in the embodiment of the present invention can be used.

  As shown in FIGS. 3B and 3C, the UV light emitting element 10A includes an element substrate 11, an n-type AlGaN: Si layer 12, a light emitting layer 13, a p-type AlGaN: Mg layer 14, and a p-type. A transparent electrode 140 made of ITO (Indium Tin Oxide) is provided on the AlGaN: Mg layer 14. A p-side electrode 15B is formed on the transparent electrode 140. The transparent electrode 140 diffuses the carriers injected from the p-side electrode 15B and injects them into the p-type AlGaN: Mg layer 14.

  As shown in FIG. 3C, the UV light-excited yellow light-emitting material 121 has a notch in a portion corresponding to the p-side electrode 15 </ b> B and the n-side electrode 15 </ b> A formed on the n-type AlGaN: Si layer 12. It is formed in a square shape. The composition of the UV light-excited yellow light-emitting material 121 is the same as the composition of the UV light-excited yellow light-emitting material in the embodiment of the present invention.

  As shown in FIG. 3A, the n-side electrode 15 </ b> A of the UV light emitting element 10 </ b> A is connected to the wiring part 31 of the ceramic substrate 3 by a bonding wire 311. Further, the p-side electrode 15B of the UV light emitting element 10A is connected to the wiring part 32 of the ceramic substrate 3 by a bonding wire 321.

  When the UV light emitting element 10A configured as described above is energized, electrons are injected into the light emitting layer 13 through the wiring portion 31, the n-side electrode 15A, and the n-type AlGaN: Si layer 12, and the wiring portion 32, p Holes are injected into the light emitting layer 13 through the side electrode 15B, the transparent electrode 140, and the p-type AlGaN: Mg layer 14, and the light emitting layer 13 emits UV light.

  The UV light of the light emitting layer 13 passes through the p-type AlGaN: Mg layer 14 and the transparent electrode 140 and is emitted from the surface 140 b of the transparent electrode 140. That is, the surface 140b of the transparent electrode 140 is a light emitting surface of the UV light emitting element 10A. The light emitted from the surface 140 b of the transparent electrode 140 is incident on the first surface 121 a of the UV light-excited yellow light-emitting material 121.

The UV light incident on the UV light-excited yellow light-emitting material 121 from the first surface 121a excites the UV light-excited yellow light-emitting material 121 as excitation light. The UV light-excited yellow light emitting material 121 absorbs the UV light from the UV light emitting element 10A, and converts the wavelength of the absorbed light into mainly yellow light. More specifically, the UV light-excited yellow light-emitting material 121 is yellow light having a light emission peak wavelength in the range of 500 to 630 nm when excited by UV light having a light emission peak wavelength in the range of 250 to 425 nm from the light emitting element 10A. To emit. Thus, the light emitting device 1A emits yellow light.
Also according to the present embodiment, the same operations and effects as those of the first embodiment can be obtained.

[Third Embodiment]
Next, a third embodiment of the present invention will be described.
FIG. 4 is a sectional view of a light emitting device according to the third embodiment of the present invention.
In the light emitting device 1B according to the third embodiment of the present invention, the configuration in which the light emitted from the light emitting element is incident on the UV light-excited yellow light emitting material made of a single single crystal and converted in wavelength is the light emission according to the first embodiment. Although common to the apparatus 1, the arrangement position of the UV light-excited yellow light-emitting material is different from that of the first embodiment. Hereinafter, the constituent elements of the light emitting device 1B having the same functions and configurations as those described in the first or second embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 4, the light emitting device 1 </ b> B includes a UV light emitting element 10 having a configuration similar to that of the first embodiment on a ceramic substrate 3. The UV light emitting element 10 emits UV light from the second main surface 11b of the element substrate 11 (see FIG. 2B) positioned on the opening 4A side of the main body 4 toward the opening 4A side of the main body 4. .

  A UV light-excited yellow light emitting material 122 is joined to the main body 4 so as to cover the opening 4A. The UV light-excited yellow light emitting material 122 is formed in a flat plate shape and is coupled to the upper surface 4 b of the main body 4. As the UV light-excited yellow light emitting material 122, those having the respective compositions described in the embodiment of the present invention can be used. The UV light-excited yellow light-emitting material 122 is larger than the UV light-emitting element 10 and is substantially one single crystal as a whole.

  When the light emitting device 1B configured as described above is energized, the UV light emitting element 10 emits light and emits UV light from the second main surface 11b toward the UV light excitation yellow light emitting material 122. The UV light-excited yellow light-emitting material 122 enters the UV light of the light-emitting element 10 from the first surface 122a facing the emission surface of the UV light-emitting element 10, and the yellow light excited by the UV light is transmitted from the second surface 122b. Radiates outside. Thus, the light emitting device 1B emits yellow light.

  Also according to the present embodiment, the same operations and effects as described in the first embodiment can be obtained. Further, since the UV light emitting element 10 and the UV light excited yellow light emitting material 122 are separated from each other, the large UV light excited yellow light emitting material 122 is compared with the case where the UV light excited yellow light emitting material is bonded to the emission surface of the UV light emitting element 10. Can be used, and the ease of assembly of the light emitting device 1B is increased.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described.
FIG. 5 is a sectional view of a light emitting device according to the fourth embodiment of the present invention.
As shown in FIG. 5, the light emitting device 1C according to the fourth embodiment of the present invention has a third embodiment in which the positional relationship between the UV light emitting element, the substrate on which the UV light emitting element is mounted, and the UV light-excited yellow light emitting material. It is different from the form. Hereinafter, the constituent elements of the light emitting device 1C having the same functions and configurations as those described in the first, second, or third embodiment are denoted by the same reference numerals, and description thereof is omitted.

  A light emitting device 1C according to a fourth embodiment of the present invention includes a main body 5 made of white resin, a transparent substrate 6 held by a slit-like holding portion 51 formed in the main body 5, and an opening of the main body 5. The UV light-excited yellow light-emitting material 122 made of a single single crystal of Ce: TSAG system disposed so as to cover 5A and the surface opposite to the surface on the UV light-excited yellow light-emitting material 122 side of the transparent substrate 6 are mounted. The UV light emitting element 10A and wiring portions 61 and 62 for energizing the UV light emitting element 10A are provided. The composition of the UV light-excited yellow light-emitting material 122 is the same as that of the UV light-excited yellow light-emitting material according to the embodiment of the present invention.

A concave portion on a curved surface is formed at the center of the main body 5, and the surface of the concave portion is a reflecting surface 50 that reflects the emitted light of the UV light emitting element 10 </ b> A toward the UV light excited yellow light emitting material 122.
The transparent substrate 6 is made of, for example, a resin having translucency such as silicone resin, acrylic resin, PET, or a translucent member made of glassy material, single crystal or polycrystal such as sapphire, ceramics, quartz, AlN, The UV light emitting element 10A has translucency and insulating properties that allow UV light to pass therethrough. In addition, a part of the wiring portions 61 and 62 is bonded to the transparent substrate 6. The n-side electrode and the p-side electrode of the UV light emitting element 10 </ b> A and one end portions of the wiring portions 61 and 62 are electrically connected by bonding wires 611 and 621.

When the light emitting device 1 </ b> C configured as described above is energized, the UV light emitting element 10 </ b> A emits light, and part of the UV light is transmitted through the transparent substrate 6 and is incident on the first surface 122 a of the UV photoexcited yellow light emitting material 122. . Further, another part of the UV light is reflected by the reflecting surface 50 of the main body 5, passes through the transparent substrate 6, and enters the first surface 122 a of the UV light-excited yellow light-emitting material 122.
The UV light incident on the UV light-excited yellow light-emitting material 122 is absorbed by the UV light-excited yellow light-emitting material 122 and wavelength-converted. As described above, the light emitting device 1 </ b> C emits yellow light whose wavelength is converted by the UV light excitation yellow light emitting material 122.

  This embodiment also has the same effect as that of the third embodiment. Further, the light emitted from the UV light emitting element 10A to the side opposite to the UV light excited yellow light emitting material 122 side is reflected by the reflecting surface 50, passes through the transparent substrate 6, and enters the UV light excited yellow light emitting material 122. The light extraction efficiency of 1C is increased.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described.
FIG. 6 is a schematic diagram of a light-emitting device according to a fifth embodiment of the present invention, which is a cross-sectional view (a) of the light-emitting device and a cross-sectional view (b) of a light-emitting element constituting the light-emitting device.
As shown to Fig.6 (a), in the light-emitting device 1D which is the 5th Embodiment of this invention, the structure of the UV light emitting element and its arrangement | positioning differ from 3rd Embodiment. Hereinafter, the constituent elements of the light emitting device 1D having the same functions and configurations as those described in the first, second, or third embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the light emitting device 1 </ b> D, the UV light emitting element 7 is arranged on the wiring portion 32 provided on the ceramic substrate 3.
As shown in FIG. 6B, the UV light-emitting element 7 includes a β-Ga ₂ O ₃ substrate 70, a buffer layer 71, a Si-doped n ⁺ -GaN layer 72, a Si-doped n-AlGaN layer 73, an MQW ( A multiple-quantum well) layer 74, an Mg-doped p-AlGaN layer 75, an Mg-doped p ⁺ -GaN layer 76, and a p-electrode 77 are stacked in this order. An n electrode 78 is provided on the surface of the β-Ga ₂ O ₃ substrate 70 opposite to the buffer layer 71.

The β-Ga ₂ O ₃ substrate 70 is made of β-Ga ₂ O ₃ exhibiting n-type conductivity. The MQW layer 74 is a light emitting layer having a multiple quantum well structure of Al _a Ga _1-a N / Al _b Ga _1-b N (a and b are different numbers of 0 or more). The p electrode 77 is a transparent electrode made of ITO (Indium Tin Oxide), and is electrically connected to the wiring portion 32. The n electrode 78 is connected to the wiring part 31 of the ceramic substrate 3 by a bonding wire 321. As the element substrate, SiC may be used instead of β-Ga ₂ O ₃ .

When the UV light emitting element 7 configured as described above is energized, electrons are passed through the n electrode 78, the β-Ga ₂ O ₃ substrate 70, the buffer layer 71, the n ⁺ -GaN layer 72, and the n-AlGaN layer 73. Holes are injected into the MQW layer 74, and holes are injected into the MQW layer 74 through the p-electrode 77, the p ⁺ -GaN layer 76, and the p-AlGaN layer 75 to emit UV light. The UV light passes through the β-Ga ₂ O ₃ substrate 70 and the like, is emitted from the light emitting surface 7a of the UV light emitting element 7, and is incident on the first surface 122a of the UV photoexcited yellow light emitting material 122. The UV light-excited yellow light-emitting material 122 is incident on the UV light of the UV light-emitting element 7 from the first surface 122a facing the light emission surface of the UV light-emitting element 7, and the yellow light excited by the UV light is incident on the second surface. Radiates to the outside from 122b. Thus, the light emitting device 1D emits yellow light.
Also according to this embodiment, the same operations and effects as those of the third embodiment can be obtained.

[Sixth Embodiment]
Next, a sixth embodiment of the present invention will be described.
FIG. 7 is a cross-sectional view of a light emitting device according to the sixth embodiment of the present invention.
As shown in FIG. 7, in the present embodiment, the configuration is the same as that of the first embodiment except that a UV light-excited blue light-emitting material is disposed on a UV light-excited yellow light-emitting material on the UV light-emitting element. Hereinafter, constituent elements of the light-emitting device having the same functions and configurations as those described above are denoted by the same reference numerals, and description thereof is omitted.

  In the light emitting device 1E, a UV light excited blue light emitting material 95 is disposed on the UV light excited yellow light emitting material 2 on the UV light emitting element 10. Thereby, the UV light-excited yellow light-emitting material 2 emits yellow light by a part of the UV light from the UV light-emitting element 10, and the UV light-excited blue light-emitting material 95 is blue light by the remaining UV light from the UV light-emitting element 10. Radiate. Since blue and yellow have a complementary color relationship, the light emitting device 1E emits white light.

[Seventh Embodiment]
Next, a seventh embodiment of the present invention will be described.
FIG. 8 is a cross-sectional view of a light emitting device according to a seventh embodiment of the present invention.
As shown in FIG. 8, in this embodiment, the configuration is the same as that of the second embodiment except that a UV light-excited blue light-emitting material is arranged on a UV light-excited yellow light-emitting material on the UV light-emitting element. Hereinafter, constituent elements of the light-emitting device having the same functions and configurations as those described above are denoted by the same reference numerals, and description thereof is omitted.

  In the light emitting device 1F, a UV light excited blue light emitting material 96 is disposed on the UV light excited yellow light emitting material 121 on the UV light emitting element 10A. As a result, the UV light-excited yellow light-emitting material 121 emits yellow light by a part of the UV light from the UV light-emitting element 10A, and the UV light-excited blue light-emitting material 96 is blue light by the remaining UV light from the UV light-emitting element 10A. Radiate. Since blue and yellow have a complementary color relationship, the light emitting device 1F emits white light.

[Eighth Embodiment]
Next, an eighth embodiment of the present invention will be described.
FIG. 9 is a cross-sectional view of a light emitting device according to an eighth embodiment of the present invention.
As shown in FIG. 9, in this embodiment, the configuration is the same as that of the third embodiment except that a UV light-excited blue light-emitting material is disposed on a UV light-excited yellow light-emitting material. Hereinafter, constituent elements of the light-emitting device having the same functions and configurations as those described above are denoted by the same reference numerals, and description thereof is omitted.

  In the light emitting device 1G, a UV light-excited blue light-emitting material 97 is disposed on the UV light-excited yellow light-emitting material 122. As a result, the UV light-excited yellow light-emitting material 122 emits yellow light by a part of the UV light from the UV light-emitting element 10, and the UV light-excited blue light-emitting material 97 is blue light by the remaining UV light from the UV light-emitting element 10. Radiate. Since blue and yellow have a complementary color relationship, the light emitting device 1G emits white light.

[Ninth Embodiment]
Next, a ninth embodiment of the present invention will be described.
FIG. 10 is a sectional view of a light emitting device according to the ninth embodiment of the present invention.
As shown in FIG. 10, in the present embodiment, the configuration is the same as that of the fourth embodiment except that the UV light-excited blue light-emitting material is disposed on the UV light-excited yellow light-emitting material. Hereinafter, constituent elements of the light-emitting device having the same functions and configurations as those described above are denoted by the same reference numerals, and description thereof is omitted.

  In the light emitting device 1H, a UV light excited blue light emitting material 97 is disposed on the UV light excited yellow light emitting material 122. Thereby, the UV light-excited yellow light-emitting material 122 emits yellow light by a part of the UV light from the UV light-emitting element 10A, and the UV light-excited blue light-emitting material 97 is blue light by the remaining UV light from the UV light-emitting element 10A. Radiate. Since blue and yellow are in a complementary color relationship, the light emitting device 1H emits white light.

[Tenth embodiment]
Next, a tenth embodiment of the present invention will be described.
FIG. 11 is a sectional view of a light emitting device according to the tenth embodiment of the present invention.
As shown in FIG. 11, in the present embodiment, the configuration is the same as that of the fifth embodiment except that a UV light-excited blue light-emitting material is disposed on a UV light-excited yellow light-emitting material. Hereinafter, constituent elements of the light-emitting device having the same functions and configurations as those described above are denoted by the same reference numerals, and description thereof is omitted.

  In the light emitting device 1J, a UV light-excited blue light-emitting material 97 is disposed on the UV light-excited yellow light-emitting material 122. Thereby, the UV light-excited yellow light-emitting material 122 emits yellow light by a part of the UV light from the UV light-emitting element 7, and the UV light-excited blue light-emitting material 97 is blue light by the remaining UV light from the UV light-emitting element 7. Radiate. Since blue and yellow have a complementary color relationship, the light emitting device 1J emits white light.

In the sixth to tenth embodiments of the present invention, the UV light-excited blue light-emitting material is preferably a single crystal of Ce: R ₂ SiO ₅ (R is one or more of Lu, Y, and Gd). . This is because it emits light with high brightness and can be easily processed to a predetermined size and attached to a UV light emitting element or light emitting device.

In the sixth to tenth embodiments of the present invention, the UV light-excited blue light-emitting material is attached to the outside of the UV light-excited yellow light-emitting material, that is, the side opposite to the UV light-emitting element. However, the present invention is not limited to this. Alternatively, the UV light-excited blue light-emitting material may be attached to the inner side of the UV light-excited yellow light-emitting material, that is, the UV light-emitting element side.

In the sixth to tenth embodiments of the present invention, the UV light-excited yellow light-emitting materials 2, 121, and 122 and the UV light excitation are set so that the CIE chromaticity coordinates of white light are in the vicinity of (0.33, 0.33). It is preferable to adjust the plate thickness of the blue light emitting materials 95, 96, and 97. Thereby, color purity can be improved so that bluish white or yellowish white is pure white.

In the first to tenth embodiments of the present invention, the UV light emitting device is configured such that the light emitted from the UV light emitting devices 10, 10A, and 7 is incident on the UV light-excited yellow light emitting materials 2, 121, and 122. Since the UV light-excited yellow light-emitting material is disposed, the light emitted from the UV light-emitting elements 10, 10A, and 7 can efficiently excite the UV light-excited yellow light-emitting materials 2, 121, and 122 to emit light with high luminance. .
Note that the shape of the light-emitting device is not limited to the above shape.
One light emitting device may have a plurality of UV light emitting elements.
Furthermore, single crystal materials such as red phosphors and green phosphors having different color tones may be combined. Alternatively, although efficiency is somewhat inferior, it is also possible to adopt a configuration in which these are encapsulated with a binder or glass as powdered phosphors obtained by pulverizing phosphor single crystals of each color or part of colors. This is because the phosphor powder obtained by pulverizing the single crystal is superior in luminous efficiency, quantum efficiency, and temperature characteristics than the phosphor powder obtained by using the ceramic synthesis method. Thereby, at least the characteristics of the phosphor can be improved.

The UV light-excited yellow light-emitting material, the manufacturing method thereof, and the light-emitting device according to the embodiment of the present invention are not limited to the above-described embodiment, and may be implemented with various modifications within the scope of the technical idea of the present invention. Can do. Specific examples of this embodiment are shown in the following examples. However, the present invention is not limited to these examples.

(Example 1: Ce: TSAG sample)
<Single crystal production>
First, terbium oxide (Tb ₄ O ₇ ) raw material powder with a purity of 99.99%, aluminum oxide (Al ₂ O ₃ ) raw material powder with a purity of 99.99%, and scandium oxide (Sc ₂ O with a purity of 99.99%). ₃ ) Raw material powder and cerium oxide (CeO ₂ ) raw material powder having a purity of 99.99% were prepared.

Next, the above raw material powders were dry mixed to obtain a mixed powder. At this time, the CeO ₂ raw material powder contains Ce element in a proportion of 2 mol% based on the total number of moles of Tb element and Ce element (100 mol%), that is, Tb ₄ O ₇ : CeO ₂ : in molar ratio. Sc ₂ O ₃ : Al ₂ O ₃ = 1.47: 0.12: 2: 3.
Next, the mixed powder (powder raw material) was filled in an Ir crucible. The shape of the crucible was cylindrical, the diameter was about 40 mm, and the height was about 40 mm.

Next, the powder raw material was heated and dissolved from room temperature to about 1950 ° C. to obtain a solution.
Next, the tip of a 3 mm × 3 mm × 70 mm square bar-shaped seed crystal made of YAG (yttrium, aluminum, garnet) is brought into contact with this solution, and the seed crystal is rotated while rotating the seed crystal at 10 rpm. The bulk single crystal was grown by pulling up at a speed of 1 mm per hour. The crystal was grown in an N ₂ gas atmosphere, and the flow rate of N ₂ gas was 1.0 (l / min).
Thus, a transparent single crystal (crystal A: Example 1 sample) having a diameter of about 1.4 cm and a length of about 4.5 cm was obtained.
FIG. 12 is a photograph of crystal A (Example 1 sample). It was a yellowish transparent single crystal.

  When X-ray diffraction was performed on the crystal A thus obtained, it was confirmed that a garnet-type single crystal was obtained in a single phase. It was also confirmed that a part of Tb was replaced with Ce and a part of Al was replaced with Sc.

Further, the crystal A was subjected to chemical analysis by ICP (inductively coupled plasma) to confirm the composition of the single crystal (the atomic ratio of Tb, Sc, Al, and Ce).
As a result, it was confirmed that a single crystal having a composition represented by the formula: Tb _2.873 Ce _0.018 Sc _1.859 Al _3.250 O ₁₂ was obtained.

<Single crystal evaluation>
The fluorescence spectrum and excitation spectrum of this single crystal (Crystal A: Example 1 sample) were measured.
FIG. 13 is a fluorescence spectrum of Crystal A (Example 1 sample). For comparison, spectrum data of Ce: YAG is also shown. Ce: YAG and fluorescence spectrum shape were similar. A yellow fluorescence spectrum having an emission peak wavelength in the vicinity of 550 nm was obtained.

FIG. 14 is an excitation spectrum of crystal A (Example 1 sample). For comparison, the spectral data of Ce: YAG are also shown. Ce: YAG and the excitation spectrum shape were greatly different. An excitation peak wavelength not found in Ce: YAG was observed in the range of 360 to 390 nm.

<Production and evaluation of yellow light emitting device>
First, a UV light emitting device having an AlGaN layer as a light emitting layer was prepared.
Next, the obtained Ce: TSAG single crystal is diced along a plane perpendicular to the axial direction to produce a Ce: TSAG single crystal plate having a circular shape in plan view, and this is then used as the second substrate of the element substrate of the UV light emitting element. Further cut according to the size of the main surface.
Next, the cut Ce: TSAG single crystal plate was bonded to the second main surface of the element substrate of the UV light emitting element.
Next, the electrode of the UV light emitting element was joined to the wiring part formed on the ceramic substrate by the bump.
The light emitting device of Example 1 having the configuration shown in FIG.
By energizing from the wiring part, yellow light emission with high luminance was obtained.

(Example 2)
<Production and evaluation of white light emitting device>
First, a UV light emitting device having an AlGaN layer as a light emitting layer was prepared.
Next, the obtained Ce: TSAG single crystal is diced along a plane perpendicular to the axial direction to form a Ce: TSAG single crystal plate having a circular shape in plan view, and this is used as a second substrate of the element substrate of the UV light emitting element. Further cut according to the size of the main surface.
Next, the cut Ce: TSAG single crystal plate was bonded to the second main surface of the element substrate of the UV light emitting element.
Next, a Ce: Lu ₂ SiO ₅ (LSO) single crystal plate as a blue phosphor was prepared, and this was further cut according to the size of the second main surface of the element substrate of the UV light emitting element.
Next, the cut LSO single crystal plate was joined to this Ce: TSAG single crystal plate.
Next, the electrode of the UV light emitting element was joined to the wiring part formed on the ceramic substrate by the bump.
The light emitting device of Example 2 having the configuration shown in FIG.
High luminance white light emission was obtained by energizing from the wiring part.

1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1J ... light emitting device, 2 ... UV light-excited yellow light emitting material, 2a ... first surface, 2b ... second surface (light emitting surface), DESCRIPTION OF SYMBOLS 3 ... Ceramic substrate, 4, 5 ... Main body, 4A, 5A ... Opening part, 4b ... Upper surface, 6 ... Transparent substrate, 7, 10, 10A ... UV light emitting element, 11 ... Element substrate, 11a ... 1st main surface, 11b ... second main surface (light emitting surface), 12 ... n-type AlGaN: Si layer, 13 ... light emitting layer, 14 ... p-type AlGaN: Mg layer, 15A ... n-side electrode, 15B ... p-side electrode, 16 ... Bump, 20 ... crystal pulling furnace, 21 ... crucible made of iridium, 22 ... cylindrical container, 23 ... high frequency coil, 24 ... solution, 25 ... seed crystal, 26 ... growing crystal, 31, 32 ... wiring part, 40, 50 ... reflecting surface, 51 ... holding portion, 61, 62 ... wiring portion, 70 ... _Ga 2 _{O 3} substrate 71 ... buffer layer, 72 ^... n + -GaN layer, 73 ... n-AlGaN layer, 74 ... MQW layer, 75 ... p-AlGaN layer, 76 ^... p + -GaN layer, 77 ... p electrode, 78 ... n electrodes, 95, 96, 97 ... UV light-excited blue light-emitting material, 121,122 ... UV light-excited yellow light-emitting material, 121a, 122a ... first surface, 121b, 122b ... second surface, 140 ... transparent electrode, 140b ... surface (light Emission surface), 311, 321, 611, 612... Bonding wire.

Claims (12)

  UV light-excited yellow light-emitting material characterized in that it is a cerium-doped terbium, scandium, aluminum, garnet-type single crystal in which part of terbium is substituted with cerium and part of aluminum is substituted with scandium .   The UV light-excited yellow light-emitting material according to claim 1, wherein Ce element is added at a composition ratio of 5 mol% or less with respect to the total number of moles of Tb element and Ce element.   The UV photoexcited yellow light-emitting material according to claim 1 or 2, wherein a part of scandium is substituted with one or more of terbium, cerium, yttrium, lutetium, ytterbium, and thulium.   The UV photoexcited yellow light-emitting material according to any one of claims 1 to 3, wherein a part of the scandium is substituted with a combination of +2 and +4 elements. The UV light-excited yellow light-emitting material according to any one of claims 1 to 4, which is represented by the following chemical formula (I).
<Formula 1>
_{((Tb 1-z Ce z} ) 1-y L y) a (M 1-x N x) b Al c O 12-w ... (I)
In the above formula (I), L represents one or more of Sc, Y, Lu, Yb, Tm, Mg, Ca, Hf or Zr, M represents Sc, and N represents Tb, Ce, Y, Lu, Yb, Tm, Mg, Ca, Hf, or Zr represents one or more of them. a, b, c, x, y, z and w are 2.5 ≦ a ≦ 3.5, 0 <b ≦ 2.5, 2.5 ≦ c ≦ 5.5, 0 ≦ x <1, respectively. 0 ≦ y ≦ 0.5, 0.0001 ≦ z ≦ 0.05, and 0 ≦ w ≦ 0.5 are satisfied. Preparing a powder raw material containing terbium oxide, scandium oxide, aluminum oxide, and cerium oxide;
The seed crystal is pulled up from the solution obtained by heating and dissolving the powder raw material, and cerium is added by a melt growth method so that the composition ratio of Ce element to the total number of moles of Tb element and Ce element is 5 mol% or less. A process of growing terbium, scandium, aluminum, garnet type single crystals;
It has these, The manufacturing method of the UV light excitation yellow luminescent material of any one of Claims 1-5 characterized by the above-mentioned.   It has the board | plate material which consists of a UV light excitation yellow luminescent material of any one of Claims 1-5, and the UV light emitting element which has a light-projection surface, The one surface of the said board | plate material and the said light-projection surface oppose. Further, the UV light-excited yellow light-emitting material is disposed with respect to the UV light-emitting element.   8. The light emitting device according to claim 7, wherein an emission peak wavelength of the UV light emitting element is in a range of 250 to 425 nm.   The light-emitting device according to claim 7, wherein a UV light-excited yellow light-emitting material is disposed in contact with the light emission surface of the UV light-emitting element.   The light-emitting device according to claim 7, wherein a UV light-excited yellow light-emitting material is disposed apart from the light emitting surface of the UV light-emitting element.   The light-emitting device according to claim 7, wherein a UV light-excited blue light-emitting material is disposed in contact with the UV light-excited yellow light-emitting material. 12. The light emitting device according to claim 11, wherein the UV light-excited blue light emitting material is Ce: R ₂ SiO ₅ (R is one or more of Lu, Y, Gd) single crystal.