JP2005194340A - Phosphor and light-emitting element using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a light-emitting element that does not use a harmful substance such as mercury, etc., as a constituent element, is useful as a light source for lighting, display and liquid-crystal backlight replacing a fluorescent lamp with saved power consumption, has high luminance and has no problem in terms of color reproducibility and color rendering properties. <P>SOLUTION: The red light-emitting phosphor for ultraviolet light and blue light excitation is represented by general formula (La<SB>1-x-y</SB>, Eu<SB>x</SB>, Ln<SB>y</SB>)<SB>2</SB>O<SB>2</SB>S (Ln is at least one kind of trivalent rare earth element of Y, Gd, Lu, Sc, Sm and Er; y is a number satisfying 0≤y≤0.50) and comprises Li and has an Eu content x in the range of 0.02≤x≤0.50 and 5 ppm-10,000 ppm Li content. The light-emitting element is constituted by combining the red light-emitting phosphor or a white light and multicolor light emitting phosphor using the red light-emitting phosphor with an ultraviolet light, blue light and near ultraviolet light emitting LED chip having a luminescence peak in the wavelength range of 370-500 nm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is a combination of an excitation light source such as a light emitting diode (LED) emitting ultraviolet light and blue light of 350 to 500 nm, a red light emitting phosphor and white light emission and multicolor light emission phosphors using this phosphor. The present invention relates to a light emitting element used for illumination that exhibits various types of light emission, for backlights such as liquid crystal displays and portable information terminals, for indicator light sources, and for displays.

  Fluorescent lamps are known as one of the typical uses of phosphors, and have been practically used as lighting and displays for a long time. As is well known, a fluorescent lamp uses a phosphor film formed on the inner wall of a glass tube to emit light by being excited by ultraviolet rays generated by a discharge in a glass tube in which mercury vapor is sealed. It is used as a light source.

  By the way, in recent years, light emitting diodes (LEDs) and semiconductor lasers (LDs) have been used as excitation light sources as a light source for lighting that consumes less power and does not use mercury from the viewpoint of environmental problems and power saving. In combination with the above, a method has been developed in which light emitted from an LED or LD is used to excite a phosphor to emit light, and the light emitted at that time is used as a light source. For example, Japanese Patent No. 2,927,279 discloses a Ce-activated rare earth aluminate phosphor that emits blue visible light emitted from an LED chip and absorbs part of the blue light emitted from the LED chip. A light emitting diode that exhibits white light emission as a whole is disclosed by additive color mixing with yellow light emission.

  However, in the type of light source that combines the excitation light source such as LED and the phosphor disclosed in Patent No. 2,927,279, the emission wavelength of the excitation light source such as LED is limited. Restrictions such as the fact that the type of phosphor that can be emitted by the excitation light source used is extremely limited, so that the final emission color is limited to white or multicolored colors cannot be produced. was there. In addition, with regard to white, a preferred color is not reproduced under illumination, and color rendering is also a problem.

In order to solve such problems in recent years, U.S. Pat. S. P. 6294800, U.S. Pat. S. P. 6255670 et al. Introduces a method of mixing three components, green, blue and red. The phosphors used here are Ca ₈ Mg (SiO ₄ ) ₄ Cl: Eu, Mn as a green light emitting phosphor, BaMgAl ₁₀ O ₁₇ : Eu as a blue light emitting phosphor, and as a red phosphor. Y ₂ O ₂ S: Eu or Y ₂ O ₃ : Eu, Bi or the like.

  Compared with the two-color component method, the method of mixing these three components has considerably improved the reproduction of the colors reflected under the illumination of the light source. However, when the color tone of each phosphor used as a component is not preferable, the color projected under the illumination of the light source is poorly reproducible and the desired color cannot be produced. In particular, since the color tone of the red phosphor is far from the desired red color, a satisfactory white light source cannot be obtained.

As a measure for solving such a problem, in Japanese Patent Application Laid-Open No. 11-246857, (La, Eu, Sm) ₂ O ₂ S is used as a red fluorescent light in an LED light emitting device in which an LED chip that emits near ultraviolet light of around 370 nm and a phosphor are combined. It has been reported for use as a body and has been shown to be effective. The (La, Eu, Sm) ₂ O ₂ S red phosphor has efficient absorption for near ultraviolet rays around 370 nm, has a relatively good emission color with a peak wavelength of around 625 nm, and also compares luminance. Good. However, in light of market demand, the brightness is still insufficient.
Using such (La, Eu) ₂ O ₂ S or (La, Eu, Sm) ₂ O ₂ S phosphor as a red component, a white color obtained by mixing with blue, green and yellow phosphors Even in a light emitting phosphor or a multicolor phosphor, it is not possible to obtain sufficient brightness, and color reproducibility as an LED light emitting element expected as a light source for a liquid crystal or a mobile phone backlight, instead of a fluorescent lamp, The color rendering properties and characteristics such as luminance and luminous efficiency are not sufficiently met with market needs.

  In addition, in an LED light emitting element of a type exhibiting white light emission, which combines a LED chip emitting blue light and a Ce-activated rare earth aluminate phosphor that absorbs and emits part of the blue light emission of the LED chip. However, there is little red component, and sufficient color rendering properties as white are not obtained, and a phosphor that emits light in the red region with blue light of around 460 nm is desired.

Patent No. 2,927,279 U. S. P. 6294800 U. S. P. 6255670 JP-A-11-246857

  The present invention has been made in view of such circumstances. As a light source for lighting, display, and liquid crystal backlight, which replaces a power-saving fluorescent lamp that does not use harmful substances such as mercury as a constituent element, the near ultraviolet or 370 to 500 nm light source is used. Providing light sources such as phosphors having red, white and multicolored light emission and LED light emitting elements using the phosphors with high brightness, no problem in terms of color reproducibility and color rendering by excitation of light in the blue emission wavelength range The purpose is to do.

In order to achieve the above object, the present inventor has prepared an Eu-activated rare earth oxysulfide phosphor represented by the general formula (La, Eu, Ln) ₂ O ₂ S (where Ln is Y, Gd, Lu, Sc). , Sm and Er represent at least one trivalent rare earth element), rare earth oxide as a main raw material, sulfur as an auxiliary material for crystal synthesis into an oxysulfide which is a composition of a phosphor, an alkali metal compound ( Sodium carbonate, etc.) is used as a raw material, and the concentration of Li as a specific additive and Eu as a phosphor activator is varied, and the resulting phosphor is examined in detail for its luminance under ultraviolet light and blue light excitation. did.

As a result, the europium activated lanthanum oxysulfide phosphor containing Li and the europium activated lanthanum oxysulfide rare earth phosphor containing Li of the present invention set the concentration range of Li and Eu to a specific concentration region. Thus, a new fact has been found that shows efficient energy absorption in the emission wavelength region of 370 to 500 nm of the near-ultraviolet LED, and higher brightness than the conventional phosphor not containing Li. Furthermore, in the present invention, the white light emitting phosphor and the multicolor light emitting phosphor obtained by mixing the red phosphor, the blue phosphor, and the green phosphor have been found to have higher brightness than the conventional phosphor, and the present invention has been achieved. .
That is, the present invention has the following configuration.

(1) In formula _{(La 1-x-y,} Eu x, Ln y) is represented by 2 _{O 2} S, ultraviolet and blue light excitation red-emitting phosphor which is characterized by containing Li. (However, x and y represent numbers satisfying 0.02 ≦ x ≦ 0.50 and 0 ≦ y ≦ 0.50, respectively, and Ln is at least one of 3 of Y, Gd, Lu, Sc, Sm, and Er. Represents a rare earth element.)
(2) The red light emitting phosphor for exciting ultraviolet light and blue light according to (1), wherein the amount of Li is 5 ppm to 10,000 ppm with respect to the weight of the phosphor.
(3) The red light emitting phosphor for exciting ultraviolet light and blue light according to (1), wherein the amount of Li is 50 ppm to 5000 ppm based on the weight of the phosphor.
(4) In the powder diffraction X-ray spectrum by CuKα characteristic X-ray of the phosphor, the ratio I39 of the diffraction intensity I39 at the diffraction angle (2θ) of 39.2 ° and the diffraction intensity I37 at 36.7 ° of the spectrum / I37 is 0.2 ≦ I39 / I37 ≦ 10 and / or the ratio I26 between the diffraction intensity I26 at the diffraction angle (2θ) of 25.8 ° and the diffraction intensity I29 at the diffraction angle (2θ) of 28.6 ° / I29 is 0.2 ≦ I26 / I29 ≦ 10, The red light emitting phosphor for ultraviolet and blue light excitation according to (1).
(5) In the phosphor, the Eu content x is 0.10 ≦ x ≦ 0.30, and the Li content is 10 ppm to 5000 ppm with respect to the phosphor weight (1) and The red light emitting phosphor for ultraviolet and blue light excitation described in (4).

(6) White light emission and multicolor for exciting near-ultraviolet light and blue light, characterized by comprising a mixture of the red light-emitting phosphor and the green light-emitting phosphor and / or the blue light-emitting phosphor and / or the yellow light-emitting phosphor. Luminescent phosphor.
(7) As the red light emitting phosphor and the green light emitting phosphor, ZnS: Cu, Al, ZnS: Au, Al, ZnS: Au, Cu, Al, BaMgAl ₁₀ O ₁₇ : Eu, Mn, Ca ₂ MgSi ₂ O _{7: Eu, SrGa 2 S 4} : Eu, (Sr, Ca, Ba, Mg) Ga 2 S 4: Eu and _Y 2 _SiO 5: Ce, contain at least one phosphor in Tb, blue-emitting phosphor As the body, BaMgAl ₁₀ O ₁₇ : Eu or (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, Ca ₂ B ₅ O ₉ Cl: Eu, Sr ₂ MgSi ₂ O ₇ : Eu, It contains at least one phosphor of (Ca, Sr, Ba) ₃ MgSi ₂ O ₈ : Eu and ZnS: Ag, Al, and (Y, Gd) ₃ Al ₅ O ₁₂ : Ce as a yellow phosphor , (Y, Gd, Ce, Sm) ₃ Al ₅ O ₁₂ , (Y, Gd, Ce) ₃ (Al, Ga) ₅ O ₁₂ , (Y, Gd, Ce, Sm) ₃ (Al, Ga) ₅ O ₁₂ , ZnS: Au, Al, (Ca, Ce) (Si, Al) ₁₂ (O, N) ₁₆ , SrAl ₂ O ₄ : Eu, containing at least one phosphor (6) White light emitting and multicolor light emitting phosphors described in 1).
(8) An LED chip (light emitting diode chip) that emits ultraviolet light and blue light having an emission peak in a wavelength region of 370 to 500 nm, and a phosphor that emits light by receiving light emitted from an LD chip (semiconductor laser) (1 A light emitting device comprising the phosphor according to any one of (1) to (7).

  In the present invention, since the emission luminance is increased in the emission wavelength region of 370 to 500 nm of the near-ultraviolet LED by adopting the above-described configuration, the high-intensity red phosphor and white emission phosphor or multicolor emission phosphor. In addition, it is possible to obtain an LED light emitting element having high luminance and no problem in color reproducibility. By realizing such a light emitting element, it is not limited to a white light source for illumination, backlights for liquid crystal displays, personal digital assistants, etc. It is possible to provide an excellent product.

The phosphor of the present invention is manufactured as follows. Formula _{(La 1-x-y,} Eu x, Ln y) 2 O 2 S ( where, 0.02 ≦ x ≦ 0.50, Ln is Y, Gd, Lu, Sc, Sm, either Er one First, a rare earth material such as La, Eu, Y, Gd, Lu, Sc, Sm, or the like is formed from an oxide (La ₂ O ₃ , Eu) so as to form a matrix composition of 0 ≦ y ≦ 0.50). ₂ O ₃ etc.) or their compounds such as nitrates, carbonates, chlorides, etc., are weighed and mixed in a stoichiometric proportion to produce the main raw material. Next, Li, which plays an important role in the phosphor of the present invention, is a compound such as LiNO ₃ , Li ₂ S, Li ₂ O, LiOH, LiCl, Li ₂ CO ₃ , Li ₂ C ₂ O _4, and Li ₃ PO _4. Add a certain amount in the form. In addition, about the addition method of Li, the said compound may be directly dry-mixed, and about the water-soluble Li compound, it may add to the main raw material once in the form of aqueous solution, and the method of drying after paste mixing may be taken.

Next, with respect to the prepared main raw material containing a predetermined amount of Li thus obtained, the amount of sulfur S, which is an auxiliary raw material, can be expressed by a general formula, the amount of loss during the firing step is taken into account and the excess amount from the theoretical value Further, an appropriate amount of an alkali carbonate such as Na ₂ CO ₃ , K ₂ CO ₃ , Na ₂ HPO ₄ , KH ₂ PO ₄ or the like as a crystal growth agent is added and mixed. The raw material mixture obtained as described above is packed in a firing container such as an alumina crucible with a lid and fired at 1000 to 1300 ° C. for 2 to 6 hours.
The fired product after firing is immersed in water, washed with water to dissolve and remove unnecessary substances such as alkali polysulfide generated during firing, and then washed with a light mineral acid aqueous solution as needed. The phosphor of the present invention is obtained by subjecting to a dispersion treatment using a ball mill or the like, and further applying a classification treatment such as removal of unnecessary large particles by a wet classification method such as a water sieve, followed by drying and sieving. It is done. Moreover, you may perform the surface treatment of an inorganic substance or an organic substance for the improvement of durability as needed.

  With respect to the obtained phosphor containing a predetermined amount of Li of the present invention and a conventional phosphor not containing Li, the emission luminance and the excitation spectrum were measured. The brightness of the present invention and the conventional red phosphor is determined by irradiating the sample with visible light from ultraviolet rays of each wavelength, and by adjusting the light intensity of each wavelength in such a way that the obtained emitted light can cover the wavelength range of 380 to 780 nm. It was measured. In the measurement, in order to eliminate the influence of the partially incident excitation light, the wavelength range is limited to 500 nm to 780 nm, the chromaticity and luminance are obtained, and the luminance display is expressed as a relative value with respect to the luminance measurement value of the conventional phosphor. .

Table 1 shows the results of measuring the luminance at the excitation wavelengths of 385 nm, 405 nm, 415 nm, and 465 nm in the manner described above for the phosphors having different Li contents and Eu concentrations as the composition of the phosphors. .
As a result, the conventional La ₂ O ₂ S: Eu phosphor containing no Li under irradiation with an excitation wavelength of 405 nm shown in Table 1 (Comparative Example 1) and the phosphor of the present invention containing 300 ppm of Li (Example 7) It can be seen that there is a luminance improvement of 30% or more in comparison with the above, and that the addition of Li greatly affects the luminance of the resulting phosphor.
FIG. 1 is a graph showing the emission intensity of the main emission peak at 625 nm relative to each wavelength of the excitation light in the emission obtained when light having an excitation wavelength of 300 nm to 500 nm is irradiated. The excitation spectrum of the phosphor is shifted to the long wavelength side compared to the conventional phosphor, and particularly the emission intensity is high in the ultraviolet to blue wavelength region of 370 nm or more, and the energy absorption efficiency is good on the long wavelength side. Show. This means that the characteristics of the light emitting device for exciting near-ultraviolet light and blue light, which is the object of the present invention, are met.
Further, as shown in the comparison of the respective spectra in FIG. 1, in the long wavelength region, the Eu concentration tends to be higher at 0.15 mol than 0.06 mol, and higher at the Eu concentration. Yes. Note 0.06mol of Eu concentration means x = 0.06 in the above general formula _{(La 1-x-y,} Eu x, Ln y) 2 O 2 S.

  Next, regarding the luminance characteristics of the phosphor of the present invention, the relationship between the luminance of the sample using the Li amount and the Eu amount changed under irradiation with an excitation wavelength of 405 nm as light corresponding to the near-ultraviolet LED which is the object of the present invention. We investigated in detail. As shown in FIG. 2, the conventional phosphor not containing Li shows a luminance peak at an Eu concentration of 0.12 mol, whereas the phosphor containing Li of the present invention has an Eu concentration of 0. .20 mol shows a luminance peak, and the luminance is about 40% higher than the luminance of the conventional phosphor, showing a surprising effect. Further, when the effect of the Eu concentration on the luminance was examined in detail based on the effective Li concentration of 300 ppm, the Eu concentration was 0.02 = 0.50 mol as shown in FIG. 2, and the composition ratio was 0.02 ≦ x It can be seen that there is an effect on luminance in the range of ≦ 0.50). Further, it is understood that a preferable range as a practical effect is 0.05 ≦ x ≦ 0.30, and a more preferable range is 0.07 ≦ x ≦ 0.25.

When the effect of the Li concentration on the luminance under the effective Eu concentration of 0.15 mol is seen, there is an effect on the luminance in the range of the Li concentration of 5 ppm or more with respect to the phosphor weight as shown in FIG. If it exceeds the above, the dispersibility of the phosphor as a powder deteriorates and is not suitable for practical use. A more preferable range for luminance is 50 ppm to 5000 ppm.
From the above results, considering the effects of Li concentration and Eu concentration at the same time, the conditions in which Eu content x is 0.05 ≦ x ≦ 0.30 and Li content is 10 ppm to 5000 ppm are the most practical. This is a preferable area. The analysis of the concentration of Li and Eu in the phosphor was performed by ICP analysis by dissolving the phosphor in nitric acid and diluting the phosphor to an analyzable concentration.

Further, regarding the difference in properties between the phosphor of the present invention and the conventional phosphor, the powder diffraction X-ray spectrum was measured by irradiating the phosphor powder with CuKα characteristic X-rays in order to investigate the difference in physical properties other than the luminance characteristics. As a result, a spectrum as shown in FIG. 4-2 was obtained, and the peak intensity pattern was clearly different from that in FIG. 4-1, which is the diffraction spectrum of the conventional phosphor measured in the same manner. That is, the conventional phosphor matches the known peak intensity pattern as described in the JCPDS card, whereas the peak intensity pattern of the phosphor of the present invention is 2θ = 25.6 to 25.9. The (002) plane in the vicinity of ° [d = 3.5] and the (003) plane in the vicinity of 2θ = 39.2 ° [d = 2.3] are growing specifically, and the intensity ratio is different from the conventional one. It was found to be a new intensity pattern.
More specifically, the conventional phosphor has the strongest diffraction peak at a diffraction angle (2θ) of 28.6 ° [d = 3.1], and the growth of the (101) plane is remarkable on the crystal structure. Understand. In contrast, in the phosphor of the present invention, the intensity ratio of the (002) plane of 2θ = 25.6 to 25.9 ° is larger than (101) of 2θ = 28.6 ° as shown in FIG. The growth of (002) plane is remarkable.
Further, comparing the diffraction angle (2θ) of 36.7 ° with 39.2 °, the intensity of 2θ = 36.7 ° is larger than the intensity of 2θ = 39.2 ° in the conventional phosphor. On the other hand, in the phosphor of the present invention, as shown in FIG. 4A, 2θ = 39.2 ° [d = 2 than the intensity of the (102) plane at 2θ = 36.7 ° [d = 2.4]. .3] has a strong (003) plane strength and significant growth of the (003) plane.

Table 2 compares the peak intensity ratios of the diffraction X-ray spectra of the phosphor of the present invention and the conventional phosphor. The diffraction intensity at a diffraction angle (2θ) = 25.8 ° is I26, and the diffraction angle = 28. The diffraction intensity at 29 ° is 29, and the intensity ratio is expressed as I26 / I29. Similarly, the diffraction intensity at diffraction angle (2θ) = 39.2 ° is I39, and the diffraction angle is 36.7 °. And the intensity ratio of these is expressed as I39 / I37.
From the results shown in Table 2, the intensity ratio of each of the conventional phosphors is as small as 0.18, whereas the intensity ratio of the phosphor of the present invention is large, and is 0 in the case of I39 / I37. .2 ≦ I39 / I37 ≦ 10.
On the other hand, looking at the relationship with the luminance of the phosphor, as shown in FIG. 5, the intensity ratio is not less than 0.3, showing a remarkable effect on the luminance, and 0.3 ≦ I39 / I37 ≦ 10. The range is considered to be a practically preferable range.

Using the phosphor of the present invention, which has high energy absorption efficiency in the near-ultraviolet region and easily obtains high luminance, as a red component, the green light-emitting phosphor and the blue light-emitting phosphor which are other color light-emitting phosphors as shown below. By mixing with at least one of phosphor and yellow light-emitting phosphor, a white light-emitting phosphor with high luminance and a multicolor light-emitting phosphor with excellent color reproducibility and luminance can be obtained.
Specifically, as the green light emitting phosphor, ZnS: Cu, Al, ZnS: Au, Al, ZnS: Au, Cu, Al, BaMgAl ₁₀ O ₁₇ : Eu, Mn, Ca ₂ MgSi ₂ O ₇ : Eu, SrGa ₂ S ₄ : Eu, (Sr, Ca, Ba, Mg) Ga ₂ S ₄ : Eu, Y ₂ SiO ₅ : Ce, Tb and the like, and as a blue light emitting phosphor, BaMgAl ₁₀ O ₁₇ : Eu or (Sr, _{Ca, Ba, Mg) 10 (} PO 4) 6 Cl 2: Eu, Ca 2 B 5 O 9 Cl: Eu, Sr 2 MgSi 2 O 7: Eu, (Ca, Sr, Ba) 3 MgSi 2 O 8: Eu ZnS: Ag, Al, etc., and yellow phosphors (Y, Gd) ₃ Al ₅ O ₁₂ : Ce, (Y, Gd, Ce, Sm) ₃ Al ₅ O ₁₂ , (Y, Gd, Ce) ₃ (Al, Ga _{5 O 12, (Y, Gd} , Ce, Sm) 3 (Al, Ga) 5 O 12, ZnS: Au, Al, (Ca, Ce) (Si, Al) 12 (O, N) 16, SrAl 2 O ₄ : Eu etc. can be used as a preferable thing.

On the other hand, the light emitting device of the present invention using the phosphor of the present invention emits near-ultraviolet light and blue light having a light emission peak in the wavelength range of 370 to 500 nm and light emitted from the LED chip. 6 is a red light emitting element, a white light emitting element and a multicolor light emitting LED element, each of which has a schematic structure as shown in FIG. 6, and is specifically manufactured as follows.
First, as the light emission for excitation, which is one of the constituent elements, a light-emitting element that emits light in the near ultraviolet to short wavelength visible light wavelength range is used. The light-emitting element that is the excitation light source is a light-emitting element having an emission peak wavelength λ of 370 to 500 nm, more preferably (Ga _1-x In _x ) N (wherein 390 to 430 nm and 460 to 480 nm) A light emitting diode (LED) or a semiconductor laser (LD) made of a nitride compound semiconductor such as 0 ≦ x ≦ 0.5 can be used.

The light-emitting element of the present invention has a positional relationship such that the phosphor can receive and absorb light from the excitation light source, and is configured to face the excitation light source. As shown in FIG. 6, the semiconductor light emitting element LED chip 3 is electrically bonded on the stem 1, while the other electrode of the LED chip 3 and one of the electrode terminals 2 are connected by a gold wire 4. Electrically connected.
A dome-shaped transparent resin mold 5 is fixed to the stem 1. Then, a phosphor layer 6 (phosphor + resin) is formed on the inner surface of the transparent resin mold 5 by applying a binder in which the phosphor is dispersed. The resin mold 5 is made of a resin such as an epoxy resin, an acrylic resin, a silicon resin, or polystyrene, and is fixed to the stem 1 while serving as an airtight sealing cap for the LED chip 3. When the electrode terminal 2 is energized, the LED chip 3 emits light, and this emitted light is applied to the surface of the phosphor layer 6 formed on the inner wall surface of the transparent resin mold 5 through the space layer. Is excited by absorbing light emitted from the LED chip 3, and emits light unique to the phosphor shown as a component of the present invention at a light emission wavelength different from that of the LED chip 3.

  In the phosphor layer which is one component of the light emitting device of the present invention having such a configuration, the white light emitting phosphor or the multicolor light emission mixed with the red phosphor of the present invention or a plurality of phosphors having different emission colors. By using the phosphor, it is possible to obtain a light-emitting element having high luminance and having no problem with color reproducibility and color rendering. By realizing such a light emitting device, high brightness, color reproducibility and color rendering can be achieved not only for white light sources but also for multi-color light sources such as backlights for lighting, liquid crystal displays and portable information terminals, indicator light sources and displays. It is possible to provide a product with excellent properties, and the industrial utility value is great.

EXAMPLES Next, although an Example demonstrates this invention, this invention is not limited to the embodiment illustrated to the following example.
[Example 1]
As a phosphor starting material, 180 g of La ₂ O ₃ and 34.3 g of Eu ₂ O ₃ are mixed, and then 4.8 g of LiNO ₃ is added as a Li source necessary for producing the phosphor of the present invention. Next, 48.0 g of Li ₂ CO ₃ , 9.0 g of K ₂ CO ₃ as an auxiliary material, 21.2 g of KH ₂ PO ₄ and 52.1 g of S were added and mixed to prepare a formulation. The obtained mixture was filled in an alumina crucible, covered and fired at a maximum temperature of 1150 ° C. Next, the obtained fired product was sufficiently washed with pure water to remove impurities such as alkali polysulfide, and diluted hydrochloric acid was added in the phosphor slurry state to remove unnecessary alkali substances adhering to the phosphor surface. .
Thereafter, dispersion treatment, drying, and sieving are performed to obtain (La _0.85 , Eu _0.15 ) ₂ O ₂ S phosphor containing 950 ppm of Li of Example 1 and having an Eu concentration of 0.15 mol. It was. The composition of the obtained phosphor and the amounts of contained Li and Eu were confirmed by X-ray diffraction analysis and ICP analysis. Moreover, content of Li of this invention fluorescent substance produced without performing pickling was 4100 ppm.

As shown in Table 1, the luminance of this phosphor under the near ultraviolet ray of 405 nm is 165% of that of the phosphor of Comparative Example 1 below, and the phosphor of Comparative Example 2 having the same Eu concentration. In contrast, the brightness was 40% or more, and the brightness was greatly improved. Furthermore, the luminance when irradiated with near-ultraviolet rays of 415 nm and 465 nm and visible light with a short wavelength was 200% and 160%, respectively. The crystal structure, which is a physical characteristic of the phosphor of the present invention, was measured by powder diffraction X-ray spectrum. As a result, a spectrum as shown in FIG. 4-1 was obtained. The peak intensity pattern was clearly different from the diffraction spectrum of FIG.
As shown in Table 2, the diffraction intensity ratio (ratio I39 / I37) of I39 representing the diffraction intensity at the diffraction angle (2θ) = 39.2 ° and I37 representing the diffraction intensity at the diffraction angle = 36.7 ° is as follows. While the phosphor of the present invention was 4.5, the conventional phosphor of Comparative Example 1 was 0.18, and the difference was remarkable.
Note that the emission intensity and the diffraction intensity ratio (ratio I39 / I37) obtained from the X-ray diffraction of the phosphor of the present invention prepared without pickling are the same as those of the phosphor prepared by pickling. showed that.

[Example 2]
LiNO ₃ 3.6 g
Li ₂ CO ₃ 36.0 g
Na ₂ CO ₃ 17.2 g
K ₂ CO ₃ 9.0g
KH ₂ PO ₄ 21.2 g
S 52.1g
The Eu concentration containing 170 ppm of Li in Example 2 is 0.15 mol (La _0.85 , Eu _0.15) except that the above-described raw materials are used as the Li raw material and the auxiliary raw materials. ) A ₂ O ₂ S phosphor was obtained.
The luminance of Example 2 was measured in the same manner as in Example 1. As shown in Table 1, the luminance at 405 nm excitation was 166%, which was higher than that of the conventional phosphor of Comparative Example 1. Further, as described in Table 2, the diffraction intensity ratio (ratio I39 / I37) obtained from X-ray diffraction in the same manner as in Example 1 was 0.70, which was larger than that of the phosphor of Comparative Example 1. .

Example 3
LiNO ₃ 2.4 g
Li ₂ CO ₃ 24.0 g
Na ₂ CO ₃ 34.5 g
K ₂ CO ₃ 9.0g
KH ₂ PO ₄ 21.2 g
S 52.1g
The Eu concentration containing 110 ppm of Li in Example 3 was 0.15 mol (La _0.85 , Eu _0.15) except that the above-described raw materials were used as the Li raw material and the auxiliary raw materials. ) A ₂ O ₂ S phosphor was obtained.
The luminance of Example 3 was measured in the same manner as in Example 1. As shown in Table 1, the luminance at 405 nm excitation was 150%, which was higher than that of the conventional phosphor of Comparative Example 1. Further, as described in Table 2, the diffraction intensity ratio (ratio I39 / I37) obtained from X-ray diffraction in the same manner as in Example 1 was 0.34, which was larger than that of the phosphor of Comparative Example 1. .

Example 4
LiNO ₃ 0.96g
Li ₂ CO ₃ 9.6 g
Na ₂ CO ₃ 55.1 g
K ₂ CO ₃ 9.0g
KH ₂ PO ₄ 21.2 g
S 52.1g
The Eu concentration containing 90 ppm of Li in Example 4 is 0.15 mol (La _0.85 , Eu _0.15) except that the above-described raw materials are used as the Li raw material and the auxiliary raw materials. ) A ₂ O ₂ S phosphor was obtained.
The luminance of Example 4 was measured in the same manner as in Example 1. As shown in Table 1, the luminance at 405 nm excitation was 129%, which was higher than that of the conventional phosphor of Comparative Example 1. Further, as described in Table 2, the diffraction intensity ratio (ratio I39 / I37) obtained from X-ray diffraction in the same manner as in Example 1 was 0.28, which was larger than that of the phosphor of Comparative Example 1. .

Example 5
LiNO ₃ 0.5g
Li ₃ PO ₄ 18.1 g
Na ₂ CO ₃ 68.9 g
K ₂ CO ₃ 9.0g
S 52.1
Each of the above-described raw materials was used as the Li raw material and the auxiliary raw material, and the Eu concentration containing 130 ppm of Li in Example 5 was 0.15 mol (La _0.85 , Eu _{0. 15} ) A ₂ O ₂ S phosphor was obtained.
The luminance of Example 5 was measured in the same manner as in Example 1. As shown in Table 1, the luminance at 405 nm excitation was 130%, which was higher than that of the phosphor of Comparative Example 1. Further, the diffraction intensity ratio (ratio I39 / I37) obtained from X-ray diffraction in the same manner as in Example 1 was 0.32, which was larger than that of the phosphor of Comparative Example 1.

Example 6
As the phosphor starting materials, and 180g of _La 2 _{O 3,} except replacing _Eu 2 _{O 3} to be mixed 34.3 g, except that the 169g and _Eu 2 _{O 3} and _La 2 _{O 3} is mixed 45.8 g, In the same manner as in Example 1, a (La _0.80 , Eu _0.20 ) ₂ O ₂ S phosphor containing 810 ppm of Li and having an Eu concentration of 0.20 mol was obtained.
The luminance of Example 6 was measured in the same manner as in Example 1. As shown in Table 1, the luminance at 415 nm excitation was 197%, which was higher than that of the conventional phosphor of Comparative Example 1. Further, the diffraction intensity ratio (ratio I39 / I37) obtained from X-ray diffraction in the same manner as in Example 1 was 7.0, which was larger than that of the phosphor of Comparative Example 1.

Example 7
La ₂ O ₃ 199 g
Eu ₂ O ₃ 13.7 g
Li ₃ PO ₄ 6.0 g
Li ₂ CO ₃ 52.8 g
S 52.1g
The Li raw material and the auxiliary raw materials use the respective raw materials as described above, except that the firing temperature is 1200 ° C., and contains 300 ppm of Li in Example 7 and has an Eu concentration of 0.06 mol ( La _0.94 , Eu _0.06 ) ₂ O ₂ S phosphor was obtained.
The luminance of Example 7 was measured in the same manner as in Example 1. As shown in Table 1, the luminance at 415 nm excitation was 160%, which was higher than that of the phosphor of Comparative Example 1. Further, the diffraction intensity ratio (ratio I39 / I37) obtained from X-ray diffraction in the same manner as in Example 1 was 5.0, which was larger than that of the phosphor of Comparative Example 1.

Example 8
As the phosphor starting materials, and 180g of _La 2 _{O 3,} instead that the _Eu 2 _{O 3} are mixed 34.3 g, _La 2 _{O 3} and 23.6g of 159g and _Gd 2 _{O 3,} the _Eu 2 _{O 3} (La _0.75 , Gd _0.10 , Eu _0.15 ) ₂ O ₂ S phosphor containing 660 ppm of Li and 0.15 mol of Eu in the same manner as in Example 1 except that 34.3 g was mixed Got.
The luminance of Example 8 was measured in the same manner as in Example 1. As shown in Table 1, the luminance at 405 nm excitation was 132%, which was higher than that of the phosphor of Comparative Example 1. Further, the diffraction intensity ratio (ratio I39 / I37) obtained from X-ray diffraction in the same manner as in Example 1 was 3.9, which was larger than the phosphor of Comparative Example 1 itself.

Example 9
As phosphor starting material, and 180g of _La 2 _{O 3,} except replacing _Eu 2 _{O 3} to be mixed 34.3 g, 159 g of _La 2 _{O 3} and _Y 2 _{O 3} and 14.7 g, the _Eu 2 _{O 3} 34 (La _0.75 , Y _0.10 , Eu _0.15 ) ₂ O ₂ S phosphor containing 570 ppm of Li and 0.15 mol of Eu in the same manner as in Example 1 except that 3 g was mixed. Obtained.
The luminance of Example 9 was measured in the same manner as in Example 1. As described in Table 1, the luminance at 405 nm excitation was 130%, which was higher than that of the phosphor of Comparative Example 1. Further, the diffraction intensity ratio (ratio I39 / I37) obtained from X-ray diffraction in the same manner as in Example 1 was 3.7, which was larger than that of the phosphor of Comparative Example 1.

Example 10
As the starting material in Example 1, and 180g of _La 2 _{O 3,} except replacing _Eu 2 _{O 3} to be mixed 34.3 g, and 148g of _La 2 _{O 3,} except that mixing 68.6g of _Eu 2 _{O 3} Obtained a (La _0.70 , Eu _0.30 ) ₂ O ₂ S phosphor containing 700 ppm of Li and having an Eu concentration of 0.30 mol in the same manner as in Example 1.
The luminance of Example 10 was measured in the same manner as in Example 1. As shown in Table 1, the luminance at 415 nm excitation was 151%, which was higher than that of the phosphor of Comparative Example 1. The diffraction intensity ratio (ratio I39 / I37) obtained from X-ray diffraction in the same manner as in Example 1 was 4.6, which was larger than that of the phosphor of Comparative Example 1.

[Comparative Example 1]
As a phosphor starting material, 199 g of La ₂ O ₃ and 13.7 g of Eu ₂ O ₃ were mixed, then 75.8 g of Na ₂ CO ₃ , 11.1 g of Na ₂ HPO ₄ and 52.1 g of S were added. Then, in the same manner as in Example 1 except that the firing temperature is 1200 ° C., the Eu concentration not containing Li in Comparative Example 1 is 0.06 mol (La _0.94 , Eu _0.06 ) ₂ O _2. An S phosphor was prepared. The luminance of this phosphor obtained when measured in the same manner as in Example 1 was set to 100%.

[Comparative Example 2]
As a phosphor starting material, 180 g of La ₂ O ₃ and 34.3 g of Eu ₂ O ₃ were mixed, then 68.9 g of Na ₂ CO ₃ , 21.2 g of KH ₂ PO ₄ and 52.1 g of S were added. In the same manner as in Example 1 except that the firing temperature is 1200 ° C., the (La _0.85 , Eu _0.15 ) ₂ O ₂ S phosphor having a Eu concentration not containing Li is 0.15 mol. Got. The luminance of this phosphor obtained when measured in the same manner as in Example 1 was set to 100%.

Example 11
(La _0.94 , Eu _0.06 ) ₂ O ₂ S red phosphor and BaMgAl ₁₀ O ₁₇ : Eu, Mn phosphor and BaMgAl ₁₀ O ₁₇ : Eu fluorescence containing Li of the present invention described in Example 1 The body was mixed so that the chromaticity values were x = 0.31 and y = 0.33, and the white light-emitting phosphor of Example 11 was obtained. When the luminance of the phosphor of Example 11 was measured in the same manner as in Example 1, the luminance at 415 nm excitation was 135%, which was 35% higher than that of the phosphor of Comparative Example 3. Also, the emission chromaticity by the CIE color system was x = 0.31 and y = 0.33, and there was no problem with the same color as Comparative Example 3 described later.

Example 12
The ratio of 2 to 8 (Li _0.85 , Eu _0.15 ) ₂ O ₂ S red phosphor and (Y, Gd) ₃ Al ₅ O ₁₂ phosphor containing Li according to the present invention described in Example 1 To obtain the phosphor of Example 12.
When the luminance of the phosphor of Example 12 was measured in the same manner as in Example 1, the luminance at 415 nm excitation was 119%, which was 19% higher than that of the phosphor of Comparative Example 4. Also, the emission chromaticity by the CIE color system was x = 0.31 and y = 0.33, and there was no problem with the same color as Comparative Example 4 described later.

[Comparative Example 3]
The (La _0.94 , Eu _0.06 ) ₂ O ₂ S red phosphor and BaMgAl ₁₀ O ₁₇ : Eu, Mn phosphor and BaMgAl ₁₀ O ₁₇ : Eu phosphor described in Comparative Example 1 have chromaticity values of x = 0.31, y = 0.33, the amount of mixture was adjusted to produce phosphors emitting white light, and the phosphor of Comparative Example 3 was obtained. The luminance of this phosphor obtained when measured in the same manner as in Example 1 was set to 100%.

[Comparative Example 4]
The (La _0.94 , Eu _0.06 ) ₂ O ₂ S red phosphor described in Comparative Example 1 and the (Y, Gd) ₃ Al ₅ O ₁₂ phosphor were mixed at a ratio of 2 to 8, and the emission chromaticity Obtained the phosphor of Comparative Example 4 with x = 0.31 and y = 0.33. The luminance of this phosphor obtained when measured in the same manner as in Example 1 was set to 100%.

Example 13
The light-emitting device of the present invention using the phosphor of the present invention contains 10 g of (La _0.85 , Eu _0.15 ) ₂ O ₂ S phosphor containing Ll described in Example 1 and an epoxy resin (Nitto Denko Corporation). Manufactured by NT8014) and 1 g of acid anhydride curing agent are mixed to prepare a phosphor coating solution, and a predetermined amount of the phosphor coating solution is dropped onto a near-ultraviolet LED chip that emits light near 400 nm and dried to produce a light emitting device. Was made.
When the light-emitting element thus obtained was energized, the emission color was red with chromaticities displayed in the CIE color system x = 0.66 and y = 0.33. The luminance was 40% brighter than Comparative Example 5 described below using the following conventional phosphor.

Example 14
A light emitting device of the present invention was fabricated in the same manner as in Example 13 except that the white phosphor of Example 11 was used instead of the phosphor of Example 1.
When the obtained light-emitting element was energized and the light emission characteristics were measured, the emission color was white with chromaticity x = 0.31 and y = 0.33 displayed in the CIE color system. The luminance was about 20% brighter than Comparative Example 6 described below using the following conventional phosphor.

[Comparative Example 5]
A light emitting device of the present invention was fabricated in the same manner as in Example 13 except that the red phosphor of Comparative Example 2 was used instead of the phosphor of Example 1. The light emitting characteristics of the light emitting element obtained in the same manner as in Example 13 were measured. Note that the luminance of the light-emitting element obtained at this time was 100%.

[Comparative Example 6]
A light emitting device of the present invention was fabricated in the same manner as in Example 13 except that the white phosphor of Comparative Example 3 was used instead of the phosphor of Example 1. The light emitting characteristics of the light emitting element obtained in the same manner as in Example 13 were measured. Note that the luminance of the light-emitting element obtained at this time was 100%.

It is a figure which shows the excitation spectrum of the conventional fluorescent substance and this invention fluorescent substance. It is a figure which illustrates the correlation of Eu density | concentration and a luminance characteristic about the conventional fluorescent substance and this invention fluorescent substance. It is a figure which illustrates the correlation with Li content of this invention fluorescent substance, and a luminance characteristic. It is a figure which shows the diffraction X-ray spectrum (XRD) of this invention fluorescent substance. It is a figure which shows the diffraction X-ray spectrum (XRD) of the conventional fluorescent substance. It is a figure which illustrates the correlation of the peak intensity ratio (I39 / I37) of a diffraction X-ray spectrum (XRD), and a brightness | luminance. It is a schematic sectional drawing which shows one Example of the light emitting element of this invention.

Explanation of symbols

1 Stem 2 Electrode Terminal 3 LED Chip 4 Gold Wire 5 Resin Mold 6 Phosphor Layer

Claims (8)

Formula _{(La 1-x-y,} Eu x, Ln y) is represented by 2 _{O 2} S, ultraviolet and blue light excitation red-emitting phosphor which is characterized by containing Li. (However, x and y represent numbers satisfying 0.02 ≦ x ≦ 0.50 and 0 ≦ y ≦ 0.50, respectively, and Ln is at least one of 3 of Y, Gd, Lu, Sc, Sm, and Er. Represents a rare earth element.) 2. The red light emitting phosphor for exciting ultraviolet light and blue light according to claim 1, wherein the amount of Li is 5 ppm to 10,000 ppm with respect to the weight of the phosphor. 2. The red light emitting phosphor for exciting ultraviolet light and blue light according to claim 1, wherein the amount of Li is 50 ppm to 5000 ppm based on the weight of the phosphor. In the powder diffraction X-ray spectrum by CuKα characteristic X-ray of the phosphor, the ratio I39 / I37 between the diffraction intensity I39 at the diffraction angle (2θ) of 39.2 ° and the diffraction intensity I37 at 36.7 ° of the spectrum is 0.2 ≦ I39 / I37 ≦ 10 and / or the ratio I26 / I29 of the diffraction intensity I26 at the diffraction angle (2θ) of 25.8 ° and the diffraction intensity I29 at the diffraction angle (2θ) of 28.6 ° is The red light emitting phosphor for exciting ultraviolet light and blue light according to claim 1, wherein 0.2 ≦ I26 / I29 ≦ 10. 5. The phosphor according to claim 1, wherein, in the phosphor, Eu content x is 0.10 ≦ x ≦ 0.30, and Li content is 10 ppm to 5000 ppm with respect to the weight of the phosphor. Red light emitting phosphor for exciting ultraviolet and blue light. White light emission and multicolor light emission phosphors for near ultraviolet and blue light excitation, comprising a mixture of the red light emission phosphor and the green light emission phosphor and / or the blue light emission phosphor and / or the yellow light emission phosphor . Examples of the red light emitting phosphor and the green light emitting phosphor include ZnS: Cu, Al, ZnS: Au, Al, ZnS: Au, Cu, Al, BaMgAl ₁₀ O ₁₇ : Eu, Mn, Ca ₂ MgSi ₂ O ₇ : Eu. , SrGa ₂ S ₄ : Eu, (Sr, Ca, Ba, Mg) Ga ₂ S ₄ : Eu, and Y ₂ SiO ₅ : Ce, Tb BaMgAl ₁₀ O ₁₇ : Eu or (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, Ca ₂ B ₅ O ₉ Cl: Eu, Sr ₂ MgSi ₂ O ₇ : Eu, (Ca , Sr, Ba) ₃ MgSi ₂ O ₈ : Eu and ZnS: Ag, containing at least one phosphor among Al, and (Y, Gd) ₃ Al ₅ O ₁₂ : Ce, (Y, Gd) Y, Gd, Ce, Sm) ₃ Al ₅ O ₁₂ , (Y, Gd, Ce) ₃ (Al, Ga) ₅ O ₁₂ , (Y, Gd, Ce, Sm) ₃ (Al, Ga) ₅ O ₁₂ , 7. The phosphor according to claim 6, comprising at least one phosphor of ZnS: Au, Al, (Ca, Ce) (Si, Al) ₁₂ (O, N) ₁₆ , SrAl ₂ O ₄ : Eu. The white light emitting and multicolor light emitting phosphor described. An LED chip (light emitting diode chip) that emits ultraviolet light and blue light having an emission peak in a wavelength region of 370 to 500 nm, and a phosphor that emits light upon receiving radiation from an LD chip (semiconductor laser). A light emitting device comprising the phosphor described in 1.

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