JPWO2013118333A1 - Phosphor and light emitting device - Google Patents

Abstract

The phosphor of the present invention has an oxynitride phosphor (A) having a peak wavelength of 590 nm to 604 nm, a fluorescence intensity of 185% to 210%, and a nitride phosphor (B) having a peak wavelength of 615 nm to 625 nm. The blending ratio of the oxynitride phosphor (A) and the nitride phosphor (B) is 4% by mass to 12% by mass, respectively, and the total of the oxynitride phosphor (A) and the nitride phosphor (B) is blended. The amount is 10 mass% or more and 24 mass% or less, and has high brightness, high temperature characteristics and long-term reliability.

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). As a red phosphor, there is a technique using a nitride phosphor called CASN or SCASN (see Patent Document 3), which is widely used. This red phosphor is properly used depending on the application. When the color rendering property is important, a long wavelength product having a peak wavelength of about 630 to 650 nm is used, and when the brightness is important, the peak wavelength is 610 to 610. A short wavelength product of about 630 nm is used. Further, the red phosphor is required to have high reliability with little reduction in luminance when used under high temperature or for a long period of time.

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

  However, there is a need for a red phosphor that balances color rendering and brightness. An object of the present invention is to provide a red phosphor in which a specific orange phosphor is blended in a specific ratio in order to improve color rendering properties and reliability without impairing reliability. An object of the present invention is to provide a white light emitting device using a red phosphor having improved properties.

  The present invention has an oxynitride phosphor (A) having a peak wavelength of 590 nm to 604 nm and a fluorescence intensity of 185% to 210% and a nitride phosphor (B) having a peak wavelength of 615 nm to 625 nm, The blending ratio of the product phosphor (A) and the nitride phosphor (B) is 4 mass% to 12 mass%, respectively, and the total blending amount of the oxynitride phosphor (A) and the nitride phosphor (B) is 10 It is a phosphor having a mass% of 24% or less.

  The phosphor is preferably 0.33 ≦ a / b ≦ 3, more preferably an acid oxynitride phosphor (A) and a nitride phosphor (B) when the mixing ratio is a and b. It is preferable that the nitride phosphor (A) is α sialon and the nitride phosphor (B) is 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.

  ADVANTAGE OF THE INVENTION According to this invention, the fluorescent substance which can balance and improve color rendering property and brightness, without impairing reliability can be provided, and the white light-emitting device using this fluorescent substance can be provided.

  The present invention has an oxynitride phosphor (A) having a peak wavelength of 590 nm to 604 nm and a fluorescence intensity of 185% to 210% and a nitride phosphor (B) having a peak wavelength of 615 nm to 625 nm, The blending ratio of the product phosphor (A) and the nitride phosphor (B) is 4 mass% to 12 mass%, respectively, and the total blending amount of the oxynitride phosphor (A) and the nitride phosphor (B) is 10 It is a phosphor having a mass% of 24% or less.

  In the present invention, the orange phosphor is mixed with the red phosphor to improve the visibility and improve the brightness. However, α sialon is used as the orange phosphor. Since α sialon is highly reliable and has high luminous efficiency, α sialon is a material suitable for preparing a highly reliable red phosphor. In addition, a phosphor having a peak wavelength of about 620 nm, called SCASN, is relatively close to α sialon and has little attenuation of light emission due to interaction when emitted by blue excitation, so a combination of both is preferable. It is.

  The peak wavelength of the oxynitride phosphor (A) is set to 590 nm to 604 nm because it improves the visibility when combined with the nitride phosphor (B) having a peak wavelength of 615 nm to 625 nm. This is because attenuation due to the action is reduced to suppress a decrease in light emission efficiency. If the peak wavelengths of the two are too close, the effect of improving the visibility, that is, the effect of improving the brightness, is reduced with respect to the nitride phosphor (B), and if it is too far, the effect of the oxynitride phosphor (A) is reduced. Of the emitted light, the proportion used for excitation of the nitride phosphor (B) increases, and the quantum efficiency of the mixture decreases and the luminance decreases.

  In the present invention, the mixing ratio of the oxynitride phosphor (A) and the nitride phosphor (B) is suitably in the range of 1: 3 to 3: 1, but they are used in combination as a red phosphor. Therefore, the optimum value varies depending on the other phosphors to be blended. In order to obtain the desired white light by exciting with blue light, it is combined with a green (and / or) yellow phosphor, but the total amount of oxynitride phosphor (A) and nitride phosphor (B) The range of 10 to 24% by mass is suitable. The blending amount of the oxynitride phosphor (A) or the nitride phosphor (B) is 4% by mass or more and 12% by mass or less.

  In the phosphor of the present invention, the reason why the fluorescence intensity of the oxynitride phosphor (A) is set to 185% or more and 210% or less is because it has the highest luminous efficiency among currently available. The reason why the peak wavelength of the nitride phosphor (B) is set to 615 nm or more and 625 nm or less is that the currently available nitride phosphor has the shortest wavelength. That is, by combining high-efficiency orange with a short wavelength red phosphor, a phosphor having both color rendering properties and luminance can be obtained. Furthermore, although both the oxynitride phosphor (A) and the nitride phosphor (B) are highly reliable, since the reliability is hardly affected by the interaction, the mixture of both is also highly reliable. It becomes.

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 was measured by using the F-7000 spectrophotometer manufactured by Hitachi High-Tech Co., Ltd. according to the following method.
<Measurement method>
1) Sample set: A quartz cell was filled with a measurement sample and a standard sample, and each sample was alternately set on a measuring machine and measured. 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 maximum peak height of 300 nm to 800 nm was read. The measurement was performed 5 times, and the average value of the remaining three points was obtained except for the maximum value and the minimum value.

  The peak wavelength of the phosphor is the wavelength of the maximum intensity when measuring the fluorescence intensity. In this measurement, the labsphere (registered trademark) spectrum manufactured by HALMA Company is used with the MCPD-7000 instantaneous multi-measurement system manufactured by Otsuka Electronics. A Ron standard reflector (99%, 2.0 “× 2.0”) was used as a standard sample. The measurement method is as follows. The sample is filled in a central plate of φ16mm with a thickness of 3mm, and lightly pressed with a quartz plate, set by grinding, excited with 455nm light, and peak heights of 300nm to 800nm are read. It was. The measurement value of the peak wavelength was the average value of the remaining three points excluding the maximum value and the minimum value of the five measurement values.

  The oxynitride phosphor (A) in the present invention is an oxynitride phosphor having a peak wavelength of 590 nm to 604 nm and a fluorescence intensity of 185% to 210%. Specifically, there is α sialon, and more specifically, YL-C190, YL-C200, YL-595a, YL-595A ′, YL-595A among Aron Bright (registered trademark) of Denki Kagaku Kogyo Co., Ltd. YL-600a, YL-600A ', and YL-600A. These are unprecedented phosphor materials having high peak intensity as currently available α-sialon phosphors.

  The nitride 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). This nitride phosphor (B) includes Intematix R6436 (peak wavelength 630 nm) and R6535 (peak wavelength 640 nm), Mitsubishi Chemical Corporation BR-102C and BR-102F (peak wavelength 630 nm) for adjusting the peak wavelength. Alternatively, BR-101A (peak wavelength: 650 nm) may be mixed.

  The oxynitride phosphor (A) and the nitride phosphor (B) are used together with a green or yellow phosphor in order to obtain white light by exciting with blue light, but make use of the characteristics of the phosphor of the present invention. Therefore, a phosphor having high luminance and high reliability is preferable. Specifically, the green phosphor is Eu-activated β sialon and Ce-activated LuAG (lutetium aluminum garnet), and the yellow phosphor is YAG (yttrium aluminum garnet), which has a basic structure. It is also possible to use an improved phosphor. In addition, by adding a silicate phosphor having a basic structure of BOS (barium orthosilicate) to the green phosphor, the color rendering can be improved. However, since the silicate phosphor is inferior in reliability, its addition It is preferable to reduce the amount. The mixing means with the oxynitride phosphor (A) and nitride phosphor (B) of the present invention 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.

  As described above, the invention from another aspect of the present application is a light-emitting device including a mixed 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 oxynitride phosphors (A) and nitride phosphors (B) in the phosphors of the present invention, comparative examples thereof, and other phosphors used by mixing them. Of the oxynitride phosphors (A) in Table 1, only P2 is a phosphor that satisfies the conditions of a peak wavelength of 590 nm to 604 nm and a fluorescence intensity of 185% to 210%. Of the nitride phosphors (B) in Table 1, only P4 is a phosphor that satisfies the conditions of a peak wavelength of 615 nm or more and 625 nm or less.

  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 4.0% by mass of the phosphor of P2 in Table 1 as the oxynitride phosphor (A), and 6% of the phosphor of P4 in Table 1 as the nitride phosphor (B). 0.0% by mass, and 90.0% by mass of the P7 green phosphor of Table 1 as other phosphors. The values of P1 to P8 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) It was mixed with “Shintaro Awatori” (ARE-310 (registered trademark)) manufactured by Shinky. A + b in Table 2 is a value when the blending ratio of P2 which is an example of the oxynitride phosphor (A) is a, and the blending ratio of P4 which is an example of the nitride phosphor (B) is b. is there. However, b contains P5, when not exceeding the compounding quantity of P4.

  The phosphor was mounted on the LED 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 a microsyringe. After mounting the phosphor, it was cured at 120 ° C., and then post-cured at 110 ° C. for 10 hours and sealed. 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. Generally, 70% or more is considered to be excellent color reproducibility, and less than 66% is considered to be inferior in color reproducibility. This is a condition adopted for general LED-TV.

  The luminance in Table 2 was evaluated by the luminous flux (lm) at 25 ° C. The measured value after applying a current of 100 mA for 10 minutes was taken. The pass condition of evaluation is 28.4 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. This value is not a standard value common to the world, but is currently considered as a guideline for highly reliable light-emitting elements.

The long-term reliability shown in Table 2 is as follows. The light flux is measured at 85 ° C. and 85% RH for 500 hours (hrs) and 2,000 hours, and then taken out and dried at room temperature. The initial value is 100%. Is the attenuation value of the luminous flux.
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.
On the other hand, Comparative Examples 1, 2, 4, 5, 6, 7, and 8 are inferior in color rendering, and Comparative Examples 2, 3, 5, and 9 have small light flux values. Further, in Comparative Examples 5, 7, and 9 in which the silicate phosphor (P6 in the table) was blended in a large amount exceeding the blending amount of the oxynitride phosphor (A) or the nitride phosphor (B), The LED package is inferior in high temperature characteristics and long-term reliability and has low reliability, and cannot be expected to 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 590 nm to 604 nm and a fluorescence intensity of 185% to 210% and a nitride phosphor (B) having a peak wavelength of 615 nm to 625 nm, A), the blending ratio of the nitride phosphor (B) is 4% by mass to 12% by mass, respectively, and the total blending amount of the oxide phosphor (A) and the nitride phosphor (B) is 10% by mass to 24% by mass. % Phosphor or less.   The blending ratio of the phosphor according to claim 1 is 0.33 ≦ a / b ≦ 3 when the blending ratio of the oxynitride phosphor (A) and the nitride phosphor (B) is a and b. A certain phosphor.   The phosphor according to claim 1 or 2, wherein the oxynitride phosphor (A) is α sialon and the nitride 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.