JP2013163726A - 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%; and a nitride phosphor (C) in which the peak wavelength is 625 nm to 635 nm, wherein the mix proportion of the phosphor (A) is 43 mass% to 80 mass%, the mix proportion of the phosphor (B) is 7 mass% to 30 mass%, and the mix proportion of the phosphor (C) is 10 mass% to 20 mass%, and the total of the phosphors (A), (B) and (C) is at least 85 mass%.

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 JP 2002-050798 A

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 604 nm and a fluorescence intensity of 190% to 210%. Body (B) and a nitride phosphor (C) having a peak wavelength of 625 nm or more and 635 nm or less, the blending ratio of the phosphor (A) is 43 mass% or more and 80 mass% or less, and the phosphor (B) The blending ratio is 7% by mass or more and 30% by mass or less, the blending ratio of the phosphor (C) is 10% by mass or more and 20% by mass or less, and the total of the phosphors (A), (B), (C) is A phosphor that is 85% by weight or more.

The phosphor is preferably blended so that 2 ≦ a / b ≦ 8 when the blending ratio a of the phosphor (A) and the blending ratio b of the phosphor (B) are set.

It is preferable that the phosphor (A) is β sialon, the phosphor (B) is α sialon, and the phosphor (C) is 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) and a nitride phosphor (C) having a peak wavelength of 625 nm or more and 635 nm or less, the blending ratio of the phosphor (A) is 43 mass% or more and 80 mass% or less, and the phosphor (B) The blending ratio is 7% by mass or more and 30% by mass or less, the blending ratio of the phosphor (C) is 10% by mass or more and 20% by mass or less, and the total of the phosphors (A), (B), (C) is The phosphor is 85% by weight or more.

By mixing these three kinds of phosphors, it was possible to obtain a phosphor with improved color rendering and reliability without impairing its high-luminance emission as compared with YAG phosphors.

The phosphor (A) is a phosphor that emits green to yellow, and the phosphor (B) is a phosphor that emits orange. Both are highly reliable oxynitride phosphors, and phosphors containing these are also highly reliable. Usually, when phosphors with different hues are blended, the excitation wavelength region and the emission wavelength region overlap each other, so that additivity does not hold and the emission peak is lower than the calculated value, but in the combination of the present invention Since the ratio of the light emission of one phosphor used for excitation of the other phosphor is low, it is almost close to the calculated value, and the peak intensity is equal to or higher than that of the YAG phosphor. Since the phosphor according to the present invention contains a larger amount of green and red components than a yellow monochromatic phosphor such as a YAG phosphor, the color rendering properties are improved. The phosphor according to the present invention needs to add phosphor (C) as a red component in order to obtain higher color rendering properties. The blending ratio of the phosphor (A) is 43 to 80% by weight, the blending ratio of the phosphor (B) is 7 to 30% by weight, and the phosphor (C). The blending ratio is 10 mass% or more and 20 mass% or less.

The fluorescence intensity of the phosphor is expressed as a relative value expressed in% with the peak height of the standard sample (YAG, more specifically, P46Y3 manufactured by Mitsubishi Chemical Corporation) as 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 to fill a sample with a thickness of 3 mm in the center% φ16 mm of an alumina stone plate, press lightly with a quartz plate, and 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 green light emitting 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-LW550G, GR-LW550G, GR-LW552E, GR-LW552F, This applies to GR-LW552G and the like. These β-sialon phosphors 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 BR-102C and BR-102F of Mitsubishi Chemical Corporation, and R6436 (peak wavelength 630 nm) of Intenatix. In addition, in the range not exceeding the amount of addition of these red phosphors, for the adjustment of the peak wavelength, Intematix R6535 (peak wavelength 640 nm), Mitsubishi Chemical Corporation BR-102D (peak wavelength 620 nm) and BR-101A ( A phosphor mixed with a peak wavelength of 650 nm may be used as the phosphor (B).

In order to maintain high brightness and high reliability, it is better that the amount of the phosphor (A), phosphor (B) and (C) is large, and when the respective blending ratios are a, b and c 85 mass% ≦ a + b + c. In order to obtain higher color reproducibility, the balance can be added with phosphors such as green, orange, and red, or high-intensity yellow phosphors. preferable.

The mixing means with the phosphors (A), (B) and (C) 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), (B) and (C) in the phosphor of the present invention, and phosphors of comparative examples thereof. 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.

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 50% by mass of the phosphor of P2 in Table 1 as the phosphor (A), 26% by mass of the phosphor of P5 in Table 1 as the phosphor (B), and phosphor (C ), The phosphor of P8 in Table 1 is blended by 17% by mass, and the phosphor of P1 in Table 1, which is a comparative example of the phosphor (A), is blended by 7% by mass. The values of P1 to P10 in the structure of the phosphor 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). In Table 1, a + b + c and a / b indicate that the blending ratio of P1 which is an example of the phosphor (A) is a, the blending ratio of P6 which is the phosphor (B) example is b, and the phosphor (C) is implemented. It is a value when the blending ratio of P8 as an example is c. However, c contains P7 and 9 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 the evaluation is 66% or more, 70% or more is excellent color reproducibility, and less than 64% is inferior color reproducibility. This is a condition that is said to be employed in LED monitors.

The luminance in Table 2 was evaluated by the luminous flux at 25 ° C. The measured value after applying a current of 90 mA for 10 minutes was taken. The pass condition of evaluation is 28.2 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, 6 to 12 are also inferior in color reproducibility, and Comparative Examples 2, 5, 10, and 13 have small light flux values. In Comparative Examples 2 to 5, 8 and 13 using a silicate phosphor outside the scope of the present invention as the phosphor (A), the LED package is inferior in high temperature characteristics and long-term reliability and has low reliability. It cannot be expected to be applied to products such as TVs 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 (4)

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% And a nitride phosphor (C) having a peak wavelength of 625 nm or more and 635 nm or less, a blending ratio of the phosphor (A) is 43% by weight or more and 80% by weight or less, and a blending ratio of the phosphor (B) is 7 The blending ratio of the phosphor (C) is 10% by mass to 20% by mass, and the total of the phosphors (A), (B), (C) is 85% by mass or more. A phosphor. The phosphor according to claim 1, which is blended so that 2 ≦ a / b ≦ 8 when the blending ratio a of the phosphor (A) and the blending ratio b of the phosphor (B) are set. The phosphor according to claim 1, wherein the phosphor (A) is β sialon, the phosphor (B) is α sialon, and the phosphor (C) is SCASN. The light-emitting device which has the fluorescent substance as described in any one of Claims 1 thru | or 3, and LED which mounted the said fluorescent substance in the light emission surface.