JP2013163729A - Phosphor and light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a phosphor that has high luminance, and that has a high temperature characteristic and long-term reliability; and a white light-emitting device using the phosphor.SOLUTION: A phosphor includes: an oxynitride phosphor (A) in which the peak wavelength is 550 nm to 555 nm and the fluorescent intensity is 240% to 260%; an oxynitride phosphor (B) in which the peak wavelength is 590 nm to 604 nm and the fluorescent intensity is 190% to 210%; a nitride phosphor (C) in which the peak wavelength is 625 nm to 635 nm; and an oxynitride phosphor (D) in which the peak wavelength is 535 nm to 540 nm and the fluorescent intensity is 240% to 260%, wherein the total of the phosphor (A) and the phosphor (B) is 30 mass% to 60 mass%, the mix proportion of the phosphor (C) is 10 mass% to 17.5 mass%, the phosphor (A) is 2.0 to 6.0 by the mass ratio of the phosphor (B), and the phosphor (D) is 3.0 to 6.0 by the mass ratio of the phosphor (C).

Description

The present invention relates to a phosphor used for an LED (Light Emitting Diode) and a light emitting device using the LED.

As a phosphor used in a white light emitting device, there is a combination of β sialon and a red light emitting phosphor (see Patent Document 1), and there is a phosphor in which a red light emitting phosphor having a specific color coordinate and a green light emitting phosphor are combined. (See Patent Document 2). On the other hand, there is also a method of obtaining white color using a yttrium aluminum garnet (hereinafter referred to as YAG) phosphor which is a yellow phosphor (see Patent Document 3). In order to distinguish from the former, such white is called “pseudo white”. A light emitting device using “pseudo white” can easily obtain high luminance, but has poor color rendering. Further, both are required to have a small decrease in luminance when used at high temperatures or for a long period of time.

JP 2007-180483 A JP 2008-166825 A Japanese Patent Laid-Open No. 10-242513

An object of the present invention is to provide a phosphor having improved color rendering and reliability without impairing its high-luminance emission as compared with a YAG phosphor. A white light emitting device using this phosphor is provided. It is to provide.

The present invention relates to an oxynitride phosphor (A) having a peak wavelength of 550 nm to 555 nm and a fluorescence intensity of 240% to 260%, and an oxynitride fluorescence having a peak wavelength of 590 nm to 600 nm and a fluorescence intensity of 190% to 210%. Body (B), a nitride phosphor (C) having a peak wavelength of 625 nm to 635 nm, and an oxynitride phosphor (D) having a peak wavelength of 535 nm to 540 nm and a fluorescence intensity of 240% to 260%. The total of the phosphor (A) and the phosphor (B) is 30% by mass to 60% by mass, the phosphor (C) is 10% by mass to 17.5% by mass, and the phosphor (A) is the phosphor. (B) is a phosphor having a mass ratio of 2.0 to 6.0 and phosphor (D) having a mass ratio of phosphor (C) of 3.0 to 6.0.

It is preferable that the phosphors (A) and (D) are β sialon, the phosphor (B) is α sialon, and the phosphor (C) is S-CASN.

An invention from another viewpoint of the present application is a light emitting device including the above-described phosphor and an LED having the phosphor mounted on a light emitting surface.

According to the present invention, it is possible to provide a phosphor with improved color rendering and reliability without impairing its high-luminance emission as compared with a YAG phosphor, and a white light emitting device using this phosphor can be provided. Can be provided.

The present invention relates to an oxynitride phosphor (A) having a peak wavelength of 550 nm to 555 nm and a fluorescence intensity of 240% to 260%, and an oxynitride fluorescence having a peak wavelength of 590 nm to 604 nm and a fluorescence intensity of 190% to 210%. Body (B), a nitride phosphor (C) having a peak wavelength of 625 nm to 635 nm, and an oxynitride phosphor (D) having a peak wavelength of 535 nm to 540 nm and a fluorescence intensity of 240% to 260%. The total of the phosphor (A) and the phosphor (B) is 30% by mass to 60% by mass, the phosphor (C) is 10% by mass to 17.5% by mass, and the phosphor (A) is the phosphor. (B) is a phosphor having a mass ratio of 2.0 to 6.0 and phosphor (D) having a mass ratio of phosphor (C) of 3.0 to 6.0.

In the present invention, a phosphor mixture similar to the peak waveform of YAG is prepared by blending the phosphor (A) and the phosphor (B), and a specific red phosphor (C) and a green color are produced for this phosphor mixture. By adding the phosphor (D), it was possible to obtain a phosphor with improved color rendering and reliability without impairing its high-luminance emission as compared with the YAG phosphor.

The reason why the peak wavelength of the oxynitride phosphor (A) according to the present invention is 550 nm or more and 555 nm or less is to emit light in a range from green to yellow, and the fluorescence intensity is 240% or more and 260% or less. The reason is to obtain high luminance.
The reason why the peak wavelength of the oxynitride phosphor (B) according to the present invention is 590 nm to 604 nm is to emit orange light, and the fluorescence intensity is 190% to 210%, To get.
Each of the oxynitride phosphors (A) and (B) is a highly reliable phosphor, but a mixture of these is also highly reliable. Normally, when phosphors with different hues are blended, the excitation wavelength region and the emission wavelength region overlap each other, so additivity does not hold, and the emission peak is based on the calculated value obtained by combining the emission peaks of individual phosphors. However, in the combination of the present invention, since the ratio of the light emission of one phosphor is used for excitation of the other phosphor, it is almost close to the calculated value, and each is sharper than YAG and has a much higher peak intensity. Since the phosphor is extremely high, the peak intensity itself is equal to or higher than that of the YAG phosphor.
The reason why the total of the phosphor (A) and the phosphor (B) is 30% by mass or more and 60% by mass or less is to obtain high color rendering while maintaining high luminance.
The reason why the phosphor (A) is 2.0 or more and 6.0 or less of the phosphor (B) by mass ratio is to obtain a YAG-like peak waveform by mixing.

The reason why the peak wavelength of the nitride phosphor (C) according to the present invention is set to 625 nm or more and 635 nm or less is to emit high-luminance red, and the peak wavelength of the oxynitride phosphor (D) is set to 535 nm or more and 540 nm or less. The reason for this is to emit green light.

In the present invention, the reason why the fluorescent intensity of the phosphor (D) is limited is to obtain high luminance.
The nitride phosphor (C) is 10% by mass or more and 17.5% by mass or less because the effect of improving the color rendering properties is clearly exhibited at 10% by mass or more. However, when the addition amount is too large, the luminance decreases. However, if the amount is further increased, the color rendering is deteriorated, and in severe cases, no white light is shown.
In the present invention, when the blending ratio of the phosphor (D) is small, the color rendering property tends to be lowered, and when it is large, the luminance tends to be lowered, and the balance with the phosphor (C) is particularly important. It is 3.0 or more and 6.0 or less by mass ratio with respect to fluorescent substance (C).

The fluorescence intensity of the phosphor is indicated by a relative value, expressed in%, where the peak height of the standard sample (YAG, specifically, P46Y3 manufactured by Mitsubishi Chemical Corporation) is 100%. The fluorescence intensity measuring instrument is an F-7000 spectrophotometer manufactured by Hitachi High-Tech Co., Ltd., and the measuring method is as follows.
<Measurement method>
1) Sample set: A quartz cell is filled with a measurement sample and a standard sample, and is alternately set in a sufficiently aged measuring machine for measurement. The filling was performed up to about 3/4 of the cell height so that the relative filling density was about 35%.
2) Measurement: Excitation with 455 nm light and reading of the peak height of 400-700 nm. The measurement was performed 5 times, and the average value of the remaining three points was obtained except for the maximum and minimum values.

The peak wavelength of the phosphor is determined as the maximum intensity wavelength when measuring the fluorescence intensity. The half-value width of the phosphor was measured using the LABsphere (registered trademark) Spectralon standard reflector (99%, 2.0 "× 2.0") manufactured by HALMACcompany using the MCPD-7000 instantaneous multi-measurement system manufactured by Otsuka Electronics. Used as a standard sample. The measuring method is that a sample is filled in a central portion φ16 mm of an alumina stone plate to a thickness of 3 mm, lightly pressed with a quartz plate, and then set by grinding. Excitation is performed with light at 455 nm, the peak height of 300 to 800 nm is read to determine the integrated intensity, and the width at half the maximum value is obtained. The measurement was performed five times, and the average value of the remaining three points was obtained except for the maximum and minimum values.

The phosphor (A) in the present invention is a luminescent oxynitride phosphor having a peak wavelength of 550 nm to 555 nm and a fluorescence intensity of 240% to 260%. Specifically, there is β sialon. More specifically, among Aron Bright (registered trademark) of Denki Kagaku Kogyo Co., Ltd., GR-LW550E, GR-LW550F, GR-LE550G, GR-LW552E, GR-LW552F, There are GR-LW552G and the like. These β-sialons are unprecedented phosphor materials that are compatible with having high peak intensity even though the peak wavelength is in the long wavelength region. In the β sialon phosphor, when the peak wavelength is in this wavelength range, the visibility is higher than that of a normal green phosphor, and thus the brightness becomes brighter, but the decrease in color reproducibility is relatively small.

The phosphor (B) in the present invention is an oxynitride phosphor having a peak wavelength of 590 nm or more and 604 nm or less. Specifically, there is α sialon, and more specifically, YL-C180, YL-C190, YL-C200, YL-595a, YL-595A ′ among Aronbright (registered trademark) of Denki Kagaku Kogyo Co., Ltd. YL595A, YL-595B, YL-600a, YL-600A ′, YL-600A, YL-600B, and the like. These are orange phosphors, which have higher visibility than red phosphors, and are sharper and higher in peak intensity than commonly used red nitride phosphors, so that high brightness is easily obtained. In addition, since the half-value width is slightly wider than β sialon, it contains a red component and exhibits a relatively high color reproducibility when combined with the phosphor (A).

The phosphor (C) in the present invention is a nitride phosphor having a peak wavelength of 625 nm or more and 635 nm or less. Specifically, it is a red phosphor abbreviated as SCASN and called Escazune. More specifically, there are Mitsubishi Chemical Corporation BR-102C and Intenatix R6436 (peak wavelength: 630 nm). In the range not exceeding the addition amount of these red phosphors, Intematix R6535 (peak wavelength 640 nm), Mitsubishi Chemical Corporation BR-102D (peak wavelength 620 nm), BR-101A (peak wavelength) A phosphor mixed with 650 nm) may be used as the phosphor (B).

The phosphor (D) in the present invention is an oxynitride phosphor having a peak wavelength of 535 nm or more and 540 nm or less and a fluorescence intensity of 240% or more and 260% or less, specifically β-sialon, more specifically, Among Aronbright (registered trademark) of Denki Kagaku Kogyo Co., Ltd., GR-SW535E, GR-SW535F, GR-SW535G, GR-SW533E, GR-SW533F, GR-SW533G, GR-SW532E, GR-SW532F, GR-SW532G, There are GR-SW531E, GR-SW531F, GR-SW531G, GR-F240SW, and the like. These β sialons are unprecedented phosphor materials that have both a short peak wavelength and a high peak intensity.

In order to maintain high luminance and high reliability, it is better that the amount of phosphor (A), phosphor (B), phosphor (C) and (D) is large, and particularly high color rendering properties are required. When it is necessary to further increase the brightness, when the total amount of the phosphors of the present invention is 100% by mass, other phosphors can be added in an amount not exceeding 15% by mass. In this case, a highly reliable phosphor blend is preferable.

The mixing means with the phosphors (A), (B), (C), (D) and other phosphors can be appropriately selected as long as it can be uniformly mixed or mixed to a desired mixing degree. In this mixing means, it is premised that impurities are not mixed and the shape and particle size of the phosphor are not clearly changed.

The invention from another viewpoint of the present application is a light emitting device including the above-described phosphor and an LED having the phosphor mounted on a light emitting surface. The phosphor when mounted on the light emitting surface of the LED is sealed by a sealing member. The sealing member includes a resin and glass, and the resin includes a silicone resin. As the LED, it is preferable to appropriately select a red light emitting LED, a blue light emitting LED, or an LED emitting another color in accordance with the color finally emitted. In the case of a blue light emitting LED, the LED is formed of a gallium nitride semiconductor. The peak wavelength is preferably from 440 nm to 460 nm, and more preferably from 445 nm to 455 nm. The size of the light emitting part of the LED is preferably 0.5 mm square or more, and the size of the LED chip can be appropriately selected as long as it has the area of the light emitting part, preferably 1.0 mm × 0.5 mm. More preferably, it is 1.2 mm × 0.6 mm.

  Examples according to the present invention will be described in detail with reference to tables and comparative examples.

The phosphors shown in Table 1 are phosphors (A) to (D) and other phosphors used in the phosphor of the present invention. Of the phosphors (A) in Table 1, only P2 is a phosphor having a peak wavelength and fluorescence intensity within the range of claim 1. Of the phosphors (B) in Table 1, only P5 is a phosphor having a peak wavelength and fluorescence intensity within the range of claim 1. Of the phosphors (C) in Table 1, only P8 is a phosphor having a peak wavelength and fluorescence intensity within the range of claim 1. Of the phosphors (D) in Table 1, only P11 is a phosphor having a peak wavelength and fluorescence intensity within the range of claim 1.

These phosphors were mixed at a ratio shown in Table 2 to obtain phosphors according to Examples and Comparative Examples.

The phosphor of Example 1 is 20.0% by mass of the phosphor of P2 in Table 1 as the phosphor (A), 10.0% by mass of the phosphor of P5 in Table 1 as the phosphor (B), As the phosphor (C), 14.0% by mass of the phosphor of P8 in Table 1 and 56.0% by mass of the phosphor of P11 in Table 1 as the phosphor (D) are blended. The values of P1 to P13 in the phosphor structure in Table 1 are mass%. When mixing phosphors, a total of 2.5 g was weighed and mixed in a plastic bag, and a rotating and rotating mixer (stock) The company was mixed with Shintaro Awatori ARE-310 (registered trademark). A + B and A / B in Table 1 are values when the blending ratio of P1 which is an example of the phosphor (A) is A and the blending ratio of P6 which is the phosphor (B) example is B. The same applies to D / C in Table 1. However, C contains P7 and P9, when not exceeding the compounding quantity of P8.

Mounting on the LED was performed by placing the LED on the bottom of the concave package body, wire bonding the electrode on the substrate, and then injecting the mixed phosphor from the microsyringe. After mounting, it was cured at 120 ° C., and post-cured at 110 ° C. for 10 hours for sealing. The LED used had an emission peak wavelength of 448 nm and a chip size of 1.0 mm × 0.5 mm.

The evaluation shown in Table 2 will be described.
As an initial evaluation in Table 2, the evaluation of color rendering was adopted. For the evaluation of color rendering, a color reproduction range was adopted, and the area was expressed as an area (%) of the NTSC standard ratio in color coordinates. The larger the number, the higher the color rendering. The pass condition for evaluation is 68% or more, 70% or more being excellent color reproducibility, and less than 66% being inferior color reproducibility. This is a condition that is said to be adopted for general LED-TVs.

The luminance in Table 2 was evaluated by the luminous flux at 25 ° C. The measured value after applying a current of 100 mA for 10 minutes was taken. The pass condition of evaluation is 28.0 lm or more. Since this value varies depending on the measuring machine and conditions, it is a value set as (lower limit value of the example) × 90% for relative comparison with the example.

The high temperature characteristics shown in Table 2 were evaluated based on attenuation with respect to a light beam at 25 ° C. It is a value when the light flux at 50 ° C., 100 ° C., and 150 ° C. is measured and 25 ° C. is taken as 100%. The pass conditions for evaluation are 97% or more at 50 ° C, 95% or more at 100 ° C, and 90% or more at 150 ° C. Although this value is not a standard value common to the world, it is considered as a standard for a highly reliable light-emitting element at present.

The long-term reliability in Table 2 is the attenuation value of the luminous flux when the initial value is set to 100% when the luminous flux is measured after being taken out after leaving at 500 ° C. and 85% RH for 500 and 2,000 hrs and dried at room temperature. .
The pass conditions for the evaluation are 96% or more at 500 hrs and 93% or more at 2,000 hrs. This is a value that cannot be achieved without a highly reliable phosphor.

As shown in Table 2, the examples of the present invention show relatively good color reproducibility and luminous flux values, and the attenuation of luminous flux when stored for a long time under high temperature or high temperature and high humidity is also relatively small.
Comparative Example 1 of the present invention is a so-called pseudo white light emitting device using YAG, which has good luminance, but is inferior in color rendering, and is less reliable than the examples. Comparative Examples 3, 4, 7, 9, 11, 13, and 14 are also inferior in color reproducibility, and Comparative Examples 2, 5, 6, 8, 10, and 12 have small light flux values. Further, in Comparative Examples 2, 3, 5, 8, and 9 in which the silicate phosphor outside the scope of the present invention is used as the phosphor (A), the LED package is inferior in high temperature characteristics and long-term reliability and has low reliability. Therefore, it can hardly be applied to products such as televisions and monitors.

  The phosphor of the present invention is used in a white light emitting device. The white light emitting device of the present invention is used for a backlight of a liquid crystal panel, an illumination device, a signal device, and an image display device.

Claims (3)

An oxynitride phosphor (A) having a peak wavelength of 550 nm to 555 nm and a fluorescence intensity of 240% to 260%, and an oxynitride phosphor (B) having a peak wavelength of 590 nm to 604 nm and a fluorescence intensity of 190% to 210% A nitride phosphor (C) having a peak wavelength of 625 nm to 635 nm, and an oxynitride phosphor (D) having a peak wavelength of 535 nm to 540 nm and a fluorescence intensity of 240% to 260%,
The total of phosphor (A) and phosphor (B) is 30% by mass or more and 60% by mass or less,
The phosphor (C) is 10 mass% or more and 17.5 mass% or less,
The mass ratio of the phosphor (A) phosphor (B) is 2.0 or more and 6.0 or less,
The phosphor whose phosphor (D) is 3.0 or more and 6.0 or less by mass ratio of the phosphor (C). The phosphor according to claim 1, wherein the phosphors (A) and (D) are β sialon, the phosphor (B) is α sialon, and the phosphor (C) is S-CASN. The light-emitting device which has the fluorescent substance as described in any one of Claim 1 or 2, and LED which mounts the said fluorescent substance in the light emission surface.