TWI509051B - Phosphor, method for production thereof, and light-emitting apparatus - Google Patents

Description

Fluorescent powder, manufacturing method thereof, and illuminating device

The present invention relates to a phosphor powder composed of a rare earth element-doped composite oxide, a method for producing the same, a phosphor-containing powder composition, a light-emitting device using the same, a display device, and an illumination device. More specifically, the present invention relates to a phosphor which emits yellow-green to orange light, which is excited by an excitation light source such as a semiconductor light-emitting device as a first luminous body, and a phosphor-containing powder composition containing the same, and uses the fluorescent powder composition. High-efficiency invention of fluorescent powder, display device and illumination device.

Light-emitting diodes (LEDs) have become the next generation of lighting due to their energy saving, environmental protection and long life. Specifically, the method for obtaining white light from the LED includes: (1) combining and mixing the three LEDs respectively emitting red light, green light, and blue light, and (2) respectively emitting the ultraviolet light emitting LED and the ultraviolet light excitation respectively. a combination of three types of phosphors that emit red, green, and blue light, and a combination of three colors of fluorescent light emitted by the phosphors, and (3) blue light emitting blue light and blue light excitation The light is combined with a yellow fluorescent phosphor having a complementary color to blue light, and the light of the blue LED and the yellow light emitted by the phosphor are mixed.

A method of obtaining a specific color light using a plurality of LEDs requires a circuit that appropriately adjusts the current of a single LED to achieve the purpose of balancing different colors. In contrast, the advantage of combining LEDs and phosphors to achieve a particular color of light is that such circuitry is not required and the cost of the LED is reduced. Therefore, many documents have proposed various proposals for phosphor powder having an LED as a light source.

At present, the commercial white LED mainly uses blue LED to excite YAG:Ce ³⁺ yellow fluorescent powder, and the blue light emitted by the blue LED is mixed with the yellow light emitted by the fluorescent powder to form white light. However, the red light component of the emission spectrum of YAG:Ce ³⁺ phosphor powder is insufficient, which results in the failure to obtain a correlated color temperature (CCT<4500 K) and a high color rendering index with a single YAG:Ce ³⁺ phosphor powder. The color rendering index, CRI>80) is warm white and light, so it is limited to the application in indoor general illumination.

In general, in order to solve the above problem, an appropriate red phosphor powder is added to the component to supplement the red component, thereby preparing a warm white LED with low color temperature and high color rendering index. However, the emission bandwidth of commercial red light phosphors with good performance is still too wide, and the preparation must be limited by high pressure, resulting in low lumen efficiency and high price.

It is therefore desirable to develop a phosphor powder that contains more red light components than YAG:Ce ³⁺ phosphor powder and has a wide half-height width and wide spectral spectrum so that red fluorescent light is not used. In the case of powder, it is combined with a blue LED to prepare a warm color white LED with a high color rendering index.

The present invention provides a phosphor powder composed of a rare earth doped composite oxide, a method for producing the same, a phosphor-containing powder composition, a light-emitting device using the same, and a display device. Placement and lighting devices.

An object of the present invention is to provide a phosphor powder comprising a crystal phase represented by Formula 1: (A _1-ab Gd _a B _b ) ₃ C ₅ D ₁₂ Formula 1

Wherein A may be at least one selected from the group consisting of Lu and La; B may be at least one selected from the group consisting of Ce, Pr, and Sm; C is B, Al, Ga, or In; D may be at least One selected from the group consisting of O and N; and 0.4 ≦ a ≦ 0.53, 0.005 ≦ b ≦ 0.5.

Examples in the composition of Formula 1, for example: (Lu _1-ab Gd _a Ce _b ) ₃ Al ₅ O ₁₂ , (La _1-ab Gd _a Ce _b ) ₃ Al ₅ O ₁₂ , (Lu _k La _1-ab Gd _a Ce _b ) ₃ Al ₅ O ₁₂ , wherein a and b are in the range as described above, 0≦k≦0.6.

Another embodiment of the composition of Formula 1 is, for example, (Lu _0.38 Gd _0.53 Ce _0.09 ) ₃ Al ₅ O ₁₂ .

Wherein, when excited by light having a wavelength of 430 to 460 nm, the chromaticity coordinates x and y of the color chromaticity in the standard chromaticity system (CIE) are 0.420 ≦ x ≦ 0.600, 0.400 ≦ y ≦ 0.570, respectively.

Among them, when excited by light having a wavelength of 430 to 460 nm, the wavelength of one emission peak is 480 nm or more. Further, the full width at half maximum of the radiation peak of the phosphor powder may be 100 nm or more. In an embodiment of the invention, its fluorescent The full width at half maximum of the radiation peak of the powder can reach 130 nm or more.

Formula 1 may also include a crystal phase represented by Formula 2: (A _1-apq Gd _a Ce _p Pr _q ) ₃ C ₅ D ₁₂ Formula 2

Wherein A may be at least one selected from the group consisting of Lu and La; C may be B, Al, Ga or In; D may be at least one selected from the group consisting of O and N; and 0.4 ≦ a ≦ 0.53 , 0.005≦p≦0.07, 0.001≦q≦0.02.

Examples in the composition of Formula 2, for example: (Lu _1-apq Gd _a Ce _p Pr _q ) ₃ Al ₅ O ₁₂ , (La _1-apq Gd _a Ce _p Pr _q ) ₃ Al ₅ O ₁₂ , (Lu _k L _A1-apq Gd _a Ce _p Pr _q ) ₃ Al ₅ O ₁₂ , wherein a, p, q are in the range as described above, 0≦k≦0.6.

Another embodiment of the composition of Formula 2 is, for example, (Lu _0.38 Gd _0.53 Ce _0.07 Pr _0.02 ) ₃ Al ₅ O ₁₂ .

Wherein, when excited by light having a wavelength of 430 to 460 nm, the chromaticity coordinates x and y of the color chromaticity in the standard chromaticity system (CIE) are 0.420 ≦ x ≦ 0.600, 0.400 ≦ y ≦ 0.570, respectively. Further, when excited by light having a wavelength of 460 nm, the full width at half maximum of the emission peak of the phosphor powder may be 100 nm or more. In an embodiment of the invention, the full width at half maximum of the radiant peak of the phosphor powder can reach 130 nm or more.

Another object of the present invention is to provide a method for producing a phosphor powder comprising: sintering a raw material in a nitrogen-containing atmosphere to obtain a phosphor powder comprising a crystal phase represented by Formula 1. , (A _1-ab Gd _a B _b ) ₃ C ₅ D ₁₂

Wherein A may be at least one selected from the group consisting of Lu and La; B may be at least one selected from the group consisting of Ce, Pr, and Sm; C may be B, Al, Ga, or In; At least one selected from the group consisting of O and N; and 0.4 ≦ a ≦ 0.53, 0.005 ≦ b ≦ 0.5; and the raw material may comprise: at least one metal compound, wherein the metal is at least one selected from the group consisting of Lu, La a group consisting of Ce, Pr, Sm, and Al.

Wherein, when the phosphor powder is excited by light having a wavelength of 430 to 460 nm, the chromaticity coordinates x and y of the color chromaticity in the standard chromaticity system (CIE) are 0.420 ≦ x ≦ 0.600, 0.400 ≦ y ≦ 0.570, respectively.

The raw material may, in detail, comprise: at least one selected from the group consisting of metal oxides, metal nitrate compounds, metal carbonate compounds, metal phosphate compounds, metal acetate compounds, metal oxalate compounds, metal fluorides, And a group consisting of metal chlorides, wherein the metal is at least one group consisting of Lu, La, Ce, Pr, Sm and Al.

The phosphor of the present invention has a large half-height width radiation peak and has a region longer than the yellow light wavelength (i.e., about 600 nm to 690 nm). Sufficient luminous intensity, so when adding a blue LED, warm white light can be emitted.

A further object of the present invention is to provide a light-emitting device, which can include: a first illuminator, which is an LED chip; and a second illuminator, disposed on a light-emitting surface of the first illuminant. The second illuminant may include a first luminescent powder, and the first luminescent powder may include at least one luminescent powder as described in Formula 1 or Formula 2.

Wherein, the light emitted by the first illuminant is blue light or UV. Further, the color rendering coefficient Ra of the light emission is greater than 80.

In the above light-emitting device, the second illuminant may further comprise a second phosphor, and the second phosphor may comprise at least one phosphor having a different wavelength from the radiant peak of the first phosphor.

In an embodiment of the above light-emitting device of the present invention, if the second phosphor powder uses a red phosphor, the color rendering coefficient Ra of the light emission may be greater than 90.

In another embodiment of the above light-emitting device of the present invention, if the second phosphor is a red phosphor and a green phosphor, the color rendering coefficient Ra of the light emission may be greater than 95.

Further, in the phosphor powder of the present invention, as long as the characteristics of the phosphor powder of the present invention are not impaired, and the luminous intensity is not greatly reduced, in one of the constituent elements of the crystal phase represented by the above formulas 1 and 2, Can be defective or replaced by other atoms.

For example, in Equation 1, the position of B can also be replaced with at least A group selected from the group consisting of transition metal elements or rare earth elements composed of Ce, Nd, Sm, Pr, Dy, Ho, Er, and Tm. Among them, Ce, Pr, or Sm is preferred.

Further, for example, in Formulas 1 and 2, all of Al or a part of Al may be substituted with B. When a raw material is added to a BN container and sintered to produce the phosphor powder of the present invention, B can be mixed into the obtained phosphor powder, so that the phosphor powder in which Al is replaced by B as described above can be produced.

Further, for example, in Formulas 1 and 2, the positions of O and or N may be replaced with anions such as S, Cl or F.

The phosphor powder of the formulas 1 and 2 of the present invention emits yellow to orange light. When excited by light with a wavelength of 430~460nm, the chromaticity coordinates x and y of the standard chromaticity system (CIE) are usually: (0.420, 0.400), (0.420, 0.570), (0.600, 0.570) and 0.600, 0.400) coordinates within the enclosed area. Preferably, the coordinates are in the region surrounded by (0.440, 0.430), (0.440, 0.530), (0.580, 0.530), and (0.580, 0.430). Therefore, in the chromaticity coordinates of the phosphor of the phosphors of the formulas 1 and 2 of the present invention, the chromaticity coordinate x is usually 0.420 or more, preferably 0.440 or more, and usually 0.600 or less, preferably 0.580 or less. . On the other hand, the chromaticity coordinate y is usually 0.400 or more, preferably 0.430 or more, and usually 0.570 or less, preferably 0.530 or less.

The fluorescence spectrum (luminescence spectrum) emitted by the phosphor powder of the formulas 1 and 2 of the present invention is not particularly limited, but is used as a yellow to orange phosphor. When excited by light having a wavelength of 430 to 460 nm, the emission peak wavelength of the light emission spectrum may be 480 nm or more, preferably 560 nm or more, more preferably 565 nm or more, more preferably 570 nm or more, and may be 680 nm or less. It is preferably 650 nm or less, more preferably 625 nm or less.

In the present invention, the external quantum efficiency of the phosphor powder of Formulas 1 and 2 may be 30% or more, preferably 35% or more, and more preferably 40% or more. In order to design a light-emitting element having a high luminous intensity, the higher the external quantum efficiency, the better. Further, the internal quantum efficiency of the phosphor powder of the present invention may be 35% or more, preferably 40% or more, and more preferably 45% or more. Here, the internal quantum efficiency refers to the ratio of the number of photons emitted by the phosphor powder to the number of photons of the excitation light absorbed by the phosphor powder. When the internal quantum efficiency is low, the luminous efficiency is low. Further, the higher the absorption efficiency of the phosphor powder of the present invention, the better. The value may be 70% or more, preferably 75% or more, and more preferably 80% or more. The external quantum efficiency is obtained from the product of the internal quantum efficiency and the absorption efficiency, and high absorption efficiency is preferable in order to have a high external quantum efficiency.

In the present invention, specific examples of the Ce source, such as CeO ₂ , Ce ₂ (SO ₄ ) ₃ , Ce ₂ (C ₂ O ₄ ) ₃ , Ce ₂ (CO ₃ ) ₃ hydrate, CeCl ₃ , CeF ₃ , Ce (NO ₃ ) ₃ hydrate, CeN, Ce(OH) ₄ and the like. Among them, CeO ₂ and CeN are preferred.

Specific examples of the La source are, for example, tantalum nitride, cerium oxide, cerium nitrate, cerium hydroxide, cerium oxalate, cerium carbonate, etc., among which cerium oxide is preferred.

Specific examples of the Gd source include, for example, tantalum nitride, cerium oxide, cerium nitrate, cerium hydroxide, cerium oxalate, cerium carbonate, and the like.

Specific examples of the Lu source include, for example, tantalum nitride, cerium oxide, cerium nitrate, cerium oxalate, and the like.

Specific examples of the Al source include, for example, AlN, Al ₂ O ₃ , Al, aluminum hydroxide, aluminum nitrate, and the like.

The weight average median diameter (D50) of each of the phosphor powder precursors may be 0.1 μm or more, preferably 0.5 μm or more, and may be 30 μm or less, preferably 20 μm or less. Therefore, the pulverization can be carried out in advance by a dry pulverizer such as a jet mill according to the type of the phosphor powder precursor. Thereby, uniform dispersion can be achieved in the mixture of the phosphor powder precursors, and the surface area of the phosphor powder precursor can be increased, thereby improving the solid phase reactivity of the mixture and suppressing the formation of the impurity phase. In particular, when the phosphor powder precursor is a nitride, it is preferred to use a nitride having a smaller particle diameter than other phosphor powder precursors from the viewpoint of reactivity.

In the light-emitting device of the present invention, the first light-emitting body can be used as an light-emitting body that excites a second light-emitting body to be described later.

In addition, the light-emitting wavelength of the first light-emitting body is not particularly limited as long as it overlaps with the absorption wavelength of the second light-emitting body to be described later, and an light-emitting body having a wide range of light-emitting wavelength regions can be used. It is preferable to use an illuminant having an emission wavelength from the ultraviolet region to the blue region, and it is more preferable to use an illuminant having an emission wavelength from the near ultraviolet region to the blue region. As a specific numerical value of the emission peak wavelength of the first luminous body, an illuminant having a peak emission wavelength of 430 nm to 480 nm is preferable in consideration of the color purity of the light-emitting device.

Specific examples of the semiconductor light-emitting device as the first light-emitting body include an LED, a semiconductor laser diode (LD), an organic electroluminescence device, and an inorganic electroluminescence device. The above is merely an example, and the illuminant which can be used as the first illuminant is not limited to the examples in the present specification.

The compound as the first illuminant is preferably a GaN-based LED or LD which is a GaN-based compound semiconductor. The reason for this is that the GaN-based LED or the LD has higher luminous power and external quantum efficiency than the SiC-based LED that emits light in the region, and the compound and the compound can provide very bright light emission with very low electric power. In the GaN-based LED or LD, a GaN-based LED or an LD having an Al _{x '} Ga _y' N light-emitting layer, a GaN light-emitting layer, or an In _{x '} Ga _{y '} N light-emitting layer is preferable. Wherein, the value of x'+y' may be in the range of 0.8 to 1.2. In the GaN-based LED, elements such as Zn and Si may be doped in these light-emitting layers to adjust the light-emitting characteristics.

The LED is preferably a sandwich heterostructure formed of a light-emitting layer, a p-layer, an n-layer, an electrode, and a substrate. Further, the first illuminant may be used alone or in combination of two or more of the illuminants in any combination and ratio.

The second illuminator in the illuminating device of the present invention is an illuminant that emits visible light under irradiation of light from the first illuminator. The second illuminant includes the luminescent powder provided by the present invention as the first luminescent powder, and may further include a second luminescent powder to be described later depending on the application. Such as orange ~ red fluorescent powder, green fluorescent powder, blue fluorescent powder, yellow fluorescent powder, etc.). Further, for example, the second illuminant may be configured by dispersing the first and second phosphors in the encapsulating material.

The second illuminant is not particularly limited in composition except for the luminescent powder of the present invention. Embodiments thereof include incorporation of a crystal precursor such as a metal oxide such as Y ₂ O ₃ , YVO ₄ , Zn ₂ SiO ₄ , Y ₃ Al ₅ O ₁₂ , Sr ₂ SiO ₄ or the like, Sr ₂ Si ₅ N ₈ such as metal nitride, Ca ₅ (PO ₄ ) ₃ Cl phosphate, and ZnS, SrS, CaS sulfide, Y ₂ O ₂ S, La ₂ O ₂ S oxysulfide, etc., and added rare earth metal, For example, ions of Ce, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, and the like, or a metal such as ions of Ag, Cu, Au, Al, Mn, Sb, etc., A phosphor powder is formed as an activating element or a co-activating element.

According to the above-mentioned phosphor powder composed of a rare earth doped composite oxide, a method for producing the same, a phosphor-containing composition, a light-emitting device using the same, a display device, and an illumination device, more red light is provided Ingredients, and a wide half-height wide spectral spectrum, which can be combined with blue LEDs to prepare high-color rendering index warm white LEDs without using red phosphor, thus improving the use of red fluorescent The problem of low lumen efficiency caused by powder can help reduce costs.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a fluorescence emission spectrum of a phosphor of the formula 1 of the present invention.

Fig. 2 is a graph showing the particle size distribution of the phosphor of the formula 1 of the present invention.

Fig. 3 is a fluorescence emission spectrum of the phosphor of the formula 2 of the present invention.

Prepare phosphor powder:

Example 1

Mixing a compound containing lanthanum oxide (Lu ₂ O ₃ ), lanthanum oxide (Lu ₂ O ₃ ), alumina (Al ₂ O ₃ ), and cerium oxide (CeO ₂ ) in a predetermined ratio (mixing time is about 0.5) Hour to 24 hours), filled into a crucible for high-temperature sintering reaction, sintering temperature between 1400 ~ 1700 ° C, sintering under nitrogen and hydrogen mixture for 0.5 to 24 hours, after the sintering is completed to room temperature, take out, after The mixture was ground in a ball mill, and the particle size was sorted by a centrifugal atomizer to obtain (Lu _0.38 Gd _0.53 ) ₃ Al ₅ O ₁₂ : 0.27 Ce powder.

Example 2

Will contain lanthanum oxide (Lu ₂ O ₃ ), lanthanum oxide (Lu ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), cerium oxide (CeO ₂ ), and cerium oxide (Pr ₂ O ₃ ) and or cesium fluoride. After the compound is uniformly mixed in a predetermined ratio (mixing time is about 0.5 hours to 24 hours), it is filled into a crucible for high-temperature sintering reaction, the sintering temperature is between 1400 and 1700 ° C, and the mixture is sintered under a nitrogen-hydrogen mixture gas. After 24 hours, the sintering was completed after dropping to room temperature, and then ground in a ball mill, and the particle diameter was sorted by a centrifugal atomizer to obtain (Lu _0.38 Gd _0.53 ) ₃ Al ₅ O ₁₂ : 0.21 Ce + 0.06 Pr powder.

Test example one:

A powder having a D50 particle size of 14 μm (Lu _0.38 Gd _0.53 ) ₃ Al ₅ O ₁₂ : 0.27 Ce was measured by a fluorescence spectrometer. The light from the excitation light source was passed through a grating monochromator having a focal length of 10 cm, and the excitation light having a wavelength of 460 nm was irradiated to the phosphor powder. The light generated by the phosphor powder under the excitation light is powdered by a grating monochromator having a focal length of 25 cm, and the light-emitting intensity of each wavelength is measured in a wavelength range of 450 nm to 700 nm, and the fluorescence spectrum of the fluorescence of FIG. 1 is obtained. Among them, the peak λ p = 585 nm.

The full width at half maximum of the light-emitting peak was calculated from the light-emitting spectrum obtained by the above method.

For the measurement of the chromaticity coordinates of the x, y chromaticity system (CIE 1931 colorimetric system), the data of the wavelength range of 450 nm to 700 nm of the luminescence spectrum obtained by the above method is calculated by the method based on JIS Z8724. The chromaticity coordinates x and y in the XYZ colorimetric system specified by JIS Z8701. The chromaticity coordinates (x, y) = (0.510, 0.482) are obtained.

Test Example 2:

The powder having a D50 particle size of 14 μm (Lu _0.38 Gd _0.53 ) ₃ Al ₅ O ₁₂ : 0.21 Ce + 0.06 Pr powder was measured by a fluorescence spectrometer. The rest of the conditions were the same as those in Test Example 1, and the fluorescence spectrum of Fig. 3 was obtained. Among them, the peak λ p1 = 585 nm, λ p2 = 610 nm, and λ p3 = 640 nm.

The full width at half maximum of the light-emitting peak was calculated from the light-emitting spectrum obtained by the above method.

For the measurement of the chromaticity coordinates of the x, y chromaticity system (CIE 1931 colorimetric system), the data of the wavelength range of 450 nm to 700 nm of the luminescence spectrum obtained by the above method is calculated by the method based on JIS Z8724. The chromaticity coordinates x and y in the XYZ colorimetric system specified by JIS Z8701. The chromaticity coordinates are obtained as (x, y) = (0.501, 0.488).

As in the foregoing embodiments, it should be understood that the purpose thereof is to exemplify the present invention. Ming, not limit. Further, from the above results, the present invention therefore provides a phosphor powder composed of a rare earth doped composite oxide and a method for producing the same, thereby solving the problems of the prior art.

Claims (13)

A phosphor powder comprising a crystal phase represented by Formula 2: (A _1-apq Gd _a Ce _p Pr _q ) ₃ C ₅ D ₁₂ wherein 2 is at least one selected from the group consisting of Lu and La C is B, Al, Ga or In; D is at least one selected from the group consisting of O and N; and 0.4 ≦ a ≦ 0.53, 0.005 ≦ p ≦ 0.07, 0.001 ≦ q ≦ 0.02. The fluorescent powder according to claim 1, wherein when excited by light having a wavelength of 460 nm, the chromaticity coordinates x and y of the standard chromaticity system (CIE) are 0.420 ≦ x 分别, respectively. 0.600, 0.400 ≦ y ≦ 0.570. The phosphor powder according to claim 1, wherein when excited by light having a wavelength of 430 to 460 nm, a wavelength of a radiation peak is 480 nm or more. The phosphor powder according to claim 1, wherein the phosphor powder has a full width at half maximum of 100 nm or more when excited by light having a wavelength of 430 to 460 nm. The phosphor powder according to claim 1, wherein when excited by light having a wavelength of 430 to 460 nm, the chromaticity coordinates x and y of the standard chromaticity system (CIE) are 0.420 分别, respectively. x≦0.600, 0.400≦y≦0.570. The phosphor powder according to claim 1, wherein the phosphor powder has a full width at half maximum of 100 nm or more when excited by light having a wavelength of 460 nm. A method for producing a phosphor powder, comprising: sintering a raw material in a nitrogen-containing atmosphere to obtain a phosphor powder comprising a crystal phase represented by Formula 2, (A _1-apq Gd _a Ce _p Pr _q ) ₃ C ₅ D ₁₂ wherein 2 is at least one selected from the group consisting of Lu and La; C is B, Al, Ga or In; D is at least one selected from the group consisting of O and N a group; and 0.4 ≦ a ≦ 0.53, 0.005 ≦ p ≦ 0.07, 0.001 ≦ q ≦ 0.02; and the raw material comprises: at least one metal compound, wherein the metal is at least one selected from the group consisting of Lu, La, Ce, Pr, and Al The group formed. The method of claim 7, wherein when the phosphor is excited by light having a wavelength of 430 to 460 nm, the chromaticity coordinates x and y of the standard chromaticity system (CIE) are respectively 0.420≦x≦0.600, 0.400≦y≦0.570. The method of claim 7, wherein the raw material comprises: at least one selected from the group consisting of metal oxides, metal nitrate compounds, metal carbonate compounds, metal phosphate compounds, metal acetate compounds, metal oxalate compounds a group consisting of a metal fluoride, and a metal chloride, wherein the metal is a group of at least one of Lu, La, Ce, Pr, and Al. A light-emitting device includes: a first illuminator, which is an LED chip; and a second illuminator, disposed on a light-emitting surface of the first illuminator, wherein the second illuminator includes a first A phosphor powder, the first phosphor powder comprising at least one phosphor powder as described in claim 1 of the patent application. The illuminating device according to claim 10, wherein the light emitted by the first illuminant is blue light or UV. The illuminating device according to claim 10, wherein the color rendering coefficient Ra of the illuminating is greater than 80. The illuminating device of claim 10, wherein the second illuminating body further comprises a second luminescent powder, and the second luminescent powder comprises at least one wavelength different from a wavelength of the radiant peak of the first luminescent powder. Fluorescent powder.