JP2015083617A - Phosphor and light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phosphor having high luminance, high temperature property and long-term reliability, and a white light-emitting device using the phosphor.SOLUTION: There is provided a phosphor containing an acid nitride phosphor (A) having a peak wave length of 540 nm to 545 nm and fluorescence intensity of 260% to 280% and a nitride phosphor having the peak wave length of 615 nm to 625 nm (B). The blended ration of the phosphor (A) is 74 mass% to 89 mass%, and the blended ratio of the phosphor (B) is 11 mass% to 19 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-type sialon and a red light emitting phosphor (see Patent Document 1), and a phosphor in which a red light emitting phosphor having a specific color coordinate and a green light emitting phosphor are combined. Yes (see Patent Document 2).

JP 2007-180483 A JP 2008-166825 A

An object of the present invention is to provide a phosphor having both high luminance and high reliability by adding an oxynitride phosphor to a specific nitride phosphor, and a white color using this phosphor. The object is to provide a light emitting device.

The present invention has an oxynitride phosphor (A) having a peak wavelength of 540 nm or more and 545 nm or less, a fluorescence intensity of 260% or more and 280% or less, and a nitride phosphor (B) having a peak wavelength of 615 nm or more and 625 nm or less. The phosphor is such that the blending ratio of (A) is 74 mass% or more and 89 mass% or less, and the blending ratio of the phosphor (B) is 11 mass% or more and 19 mass% or less.

The blending ratio of the phosphors has a relationship of a + b ≧ 88 mass% and 4.0 ≦ a / b ≦ 8.0 when the blending ratios of the phosphors (A) and (B) are a and b. It is preferable.

The phosphor (A) is preferably β-sialon and the phosphor (B) is preferably SCASN.

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 having high luminance, high temperature characteristics and long-term reliability, and a white light emitting device using the phosphor.

The present invention is a phosphor having an oxynitride phosphor (A) having a peak wavelength of 540 nm to 545 nm and a fluorescence intensity of 260% to 280% and a nitride phosphor (B) having a peak wavelength of 615 nm to 625 nm. .

By mixing these two kinds of phosphors, a phosphor having high brightness, high temperature characteristics and long-term reliability could be obtained.

The blending ratio of the phosphor (A) is 74% by mass or more and 89% by mass or less, and the blending ratio of the phosphor (B) is 11% by mass or more and 19% by mass or less. If the blending ratio of the phosphor (A) is too small, the luminance tends to be low, and if it is too large, it tends to be difficult to obtain high color rendering, so this range is preferable, and the blending ratio of the phosphor (B) is also If the amount is too small, high color rendering properties are not exhibited. If the amount is too high, white light itself tends not to be obtained. On the other hand, if the amount is too large, luminance tends to decrease and white light cannot be obtained.

The fluorescence intensity of the phosphor is expressed as a relative value in% with the peak height of the standard sample (YAG, 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: Excited with 455 nm light, the height of the maximum peak from 500 nm to 700 nm was read. 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 phosphor (A) in the present invention is a green light emitting oxynitride phosphor having a peak wavelength of 540 nm to 545 nm and a fluorescence intensity of 260% to 280%. Specifically, there is β-type sialon, and more specifically, there is Aron Bright (registered trademark) of Denki Kagaku Kogyo Co., Ltd.

The phosphor (B) in the present invention is a nitride phosphor having a peak wavelength of 615 nm or more and 625 nm or less. Specifically, it is a red phosphor abbreviated as SCASN and called Escazune, more specifically, Mitsubishi Chemical Corporation BR-102D (peak wavelength 620 nm). In this phosphor (B), in the range which does not exceed the addition amount of the phosphor (B), for the adjustment of the peak wavelength, Intematix R6436 (peak wavelength 630 nm), R6535 (peak wavelength 640 nm), Mitsubishi Chemical Corporation BR-102C, BR-102F (peak wavelength 630 nm), BR-101A (peak wavelength 650 nm), and the like may be mixed.

In order to maintain high brightness and high reliability, it is better that the blending amount of the phosphor (A) and the phosphor (B) is large. When the blending ratios are a and b, 88 mass% ≦ a + b preferable.

The phosphor (B) has a lower visibility than the phosphor (A) and is inferior in brightness. Therefore, the blending ratio is preferably low. However, when the phosphor (B) is too low, the color rendering property is lowered, which is severe. Since the LED does not show white light, the range of 4.0 ≦ a / b ≦ 8.0 is preferable.

The mixing means for the phosphors (A) and (B), and other phosphors can be appropriately selected as long as they 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 the phosphors (A) and (B) used in Examples and Comparative Examples. Of the phosphors (A) in Table 1, only P1 is a phosphor having a peak wavelength and fluorescence intensity within the range of claim 1. Of the phosphors (B) in Table 1, only P6 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 74% by mass of the phosphor of P1 in Table 1 as the phosphor (A), 13% by mass of the phosphor of P6 in Table 1 as the phosphor (B), and other fluorescence. As a body, 13 mass% of the phosphor of P4 in Table 1 which is a comparative example of (A) is blended. The values of P1 to P9 in the phosphor structure in Table 2 are mass%. For mixing phosphors, a total of 2.5 g was weighed and mixed in a plastic bag, and then a revolving mixer (stock) with 47.5 g of silicone resin (Toray Dow Corning OE6656) The company was mixed with Shintaro Awatori ARE-310 (registered trademark). In Table 2, a + b and a / b 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. However, when P7 and P8 of the phosphor (B) exceed the blending amount of P6 (Comparative Example 5 and Comparative Example 9), they are out of the scope of rights and are not subject to the value of b.

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 of evaluation is 72% or more, and it can be said that 74% or more is excellent color reproducibility, and less than 68% is inferior color reproducibility. This is a condition adopted for general LED-TV.

The luminance in Table 2 was evaluated by the luminous flux at 25 ° C. The measured value after applying a current of 60 mA for 10 minutes was taken. The pass condition of evaluation is 26.4 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 luminous flux attenuation is relatively small when stored for a long time under high temperature or high temperature and high humidity.
Comparative Examples 1, 2, 3, 4, 5, and 8 of the present invention have small light flux values, and similarly, Comparative Examples 1, 3, 4, 7, 8, and 9 have poor color reproducibility. In Comparative Examples 1, 2, 3, 4, and 6 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 (4)

An oxynitride phosphor (A) having a peak wavelength of 540 nm to 545 nm and a fluorescence intensity of 260% to 280%, and a nitride phosphor (B) having a peak wavelength of 615 nm to 625 nm. A phosphor having a blending ratio of 74 to 89% by weight and a phosphor (B) blending ratio of 11 to 19% by weight. When the blending ratio of the phosphor according to claim 1 is such that the blending ratio of the phosphors (A) and (B) is a and b, a + b ≧ 88 mass% and 4.0 ≦ a / b ≦ 8. A phosphor having a relationship of zero. The phosphor according to claim 1, wherein the phosphor (A) is β-sialon and the phosphor (B) 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.