JP2007335495A - Light emitter and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitter that can reduce color fluctuation by a single injection and hardening of a resin mixing a fluorescent material, and also to provide a method for manufacturing the same. <P>SOLUTION: The light emitter includes a light emitting element for emitting the light at least in a part of wavelengths ranging from blue ray to ultraviolet ray, a cup-shaped member surrounding the periphery of the light emitting element, and a transparent resin part mixing the fluorescent material filling a concave area of the cup-shaped member. The fluorescent material is activated with the light from the light emitting element, and a mixed light of the light from the light emitting element and the fluorescent light from the fluorescent material or the fluorescent light emitted from the fluorescent material is emitted to the external side. The transparent resin part includes at least two or more kinds of mixed fluorescent materials having different wavelengths of fluorescent light, and a ratio is equal to 10 or less in the value of the square of the grain size of respective fluorescent material × density thereof between fluorescent materials. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention combines a phosphor and a light emitting element that emits light in at least a part of a wavelength range of blue light to ultraviolet light, such as a blue light emitting diode (hereinafter referred to as blue LED), and desired light emission such as white light. The present invention relates to a light emitter configured to emit color and a method of manufacturing the same.

  More than 10 years have passed since the development of GaN-based LEDs as blue LEDs, and the LED application fields are rapidly expanding as the efficiency of LEDs themselves increases and the price decreases. In particular, coupled with the realization of white LEDs by the combination of blue LEDs and phosphors, LEDs have come to be used as light sources in the illumination field. The white LED uses a blue light from a blue LED and a phosphor that absorbs the blue light and emits a yellow light that is in a complementary color relationship. A white (pseudo white) illuminant is realized by color mixing.

  Since the conventional pseudo white light is a mixed color of blue + yellow light, the red component is insufficient, and there is a problem that the color rendering property is low for use in lighting applications. For this reason, the technique which improves the color rendering property of white LED by combining several fluorescent substance is proposed (for example, refer patent document 1).

  FIG. 1 is a cross-sectional view showing an example of a general white light emitter 10 using a light emitting element such as a blue LED or a near ultraviolet LED and a phosphor. The white light emitter 10 includes a cup-shaped member 11 having a bowl-shaped concave portion, a light-emitting element 12 mounted on the bottom surface of the cup-shaped member 11, and a transparent resin portion filled in the concave portion of the cup-shaped member 11. 13. The transparent resin portion 13 is composed of a transparent resin, for example, a transparent epoxy resin or the like, in which a fine particle phosphor 14 (wavelength conversion of light from a light emitting element and emission of blue, green, yellow, or red light) is mixed. Yes. Although not shown here, in order to function as a light emitter, in addition to this, a means for supplying electricity to the light emitting element is necessary. In some cases, a lens, a diffusion plate, and a cup-shaped member for controlling light are protected. Additional members are added. In the present invention, “color rendering properties” and “average color rendering index” have the following meanings, respectively.

-Color rendering The color rendering refers to a phenomenon in which the color looks different depending on the light source that is illuminated, and this characteristic is called color rendering. In general, the color rendering property represents the property of a light source compared with natural light. The color rendering property evaluation method of the light source is determined according to JIS Z8726.

・ Average color rendering index (Ra)
Color rendering is generally referred to as “good” or “bad” with reference to natural light, but the illumination close to that natural light is used as the reference light, and the test color specified in JIS is used as the reference. Evaluate its color rendering of lighting. The color rendering index includes an average color rendering index and a special color rendering index. The average color rendering index is a numerical value of the amount of color shift when the test color is illuminated with the sample light source and the reference light. When viewed with reference light, the value is 100, and the numerical value decreases as the color shift increases. The average color rendering index (Ra) is the reference light No. It is expressed as an average value of 1 to 8 color rendering evaluation values.
In the standard of the color rendering index by the CIE (International Lighting Commission), desirable average color rendering index is as follows.
Ra ≧ 90 ... Color comparison / inspection, clinical trial, museum.
90> Ra ≧ 80... House, hotel, restaurant, store, office, school, hospital, etc.
80> Ra ≧ 60: Factory for general work.
As described above, an average color rendering index of about 80 is required for use in general lighting applications.
JP 2003-101081 A

However, as described in Patent Document 1, in order to obtain white light with high color rendering properties, when a white light emitter is configured by combining at least two kinds of phosphors and a light emitting element such as a blue LED, There has been a problem that the color variation of individual white light emitters becomes large.
As a countermeasure, prepare multiple types of transparent resin mixed with each phosphor. First, the resin containing the first phosphor is injected into the cup-shaped member recess and cured, and then a resin containing another phosphor is added. A method of repeating injection and curing on the upper side of the first phosphor was studied.

  By this method, the color variation is reduced to a level with no problem, but in this method, it is necessary to mount and cure the phosphor several times. For this reason, a phosphor coating device such as a dispenser and an oven for curing are required several times as usual, and the time and man-hours required for production increase, resulting in an increase in cost.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light emitting body capable of reducing color variation by a single injection and curing of a phosphor-mixed resin, and a method for manufacturing the same.

  To achieve the above object, the present invention provides a light emitting element that emits light in a wavelength region of at least a part of blue light to ultraviolet light, a cup-shaped member that surrounds the light-emitting element, and a recess in the cup-shaped member. And a transparent resin portion mixed with a phosphor filled therein, and the phosphor is excited by the light from the light emitting element, and the mixed color light or phosphor of the light from the light emitting element and the fluorescence emitted from the phosphor A phosphor that emits fluorescence emitted from the outside, wherein at least two kinds of phosphors having different fluorescence wavelengths are mixed in the transparent resin portion, and the square of the particle diameter of each phosphor × density. Provided is a light emitter characterized in that the ratio between the respective phosphors of the value is 10 or less.

  In the phosphor of the present invention, it is preferable that the apparent density of at least one kind of phosphor is changed.

  In the light-emitting body of the present invention, it is preferable that all the phosphors used are present in a portion above 80% of the cup depth.

  In the present invention, a light emitting element that emits light in a wavelength region of at least a part of blue light to ultraviolet light is mounted in the concave portion of the cup-shaped member, and then at least two types of fluorescent light having different fluorescence wavelengths are formed in the concave portion. A method for producing a phosphor by filling a transparent resin mixed with a body and curing the transparent resin, each having a wavelength of fluorescence different from that of each phosphor, Provided is a method of manufacturing a light emitting device, wherein a recess is filled with a mixed material in which at least two kinds of phosphors having a ratio between phosphors of 10 or less are mixed by one coating operation.

  In the method for manufacturing a light emitter according to the present invention, the amount of movement of the phosphor having the largest movement amount among the phosphors to be used after the filling material is filled in the concave portion of the cup-shaped member and cured is the depth of the concave portion. It is preferable to fill at least two kinds of phosphors within 20% of the above by one coating operation.

  In the method for producing a luminescent material of the present invention, at least two kinds of phosphors each having a predetermined time from filling of the cup-shaped member to curing after the particle size and density of the phosphor to be used are determined once. It is preferable to apply by an application operation.

  In the method for producing a luminescent material of the present invention, it is preferable to apply at least two or more types of phosphors, each of which defines the particle size and density of the phosphor to be used due to the limitation of the standing time, by a single coating operation.

  ADVANTAGE OF THE INVENTION According to this invention, the light-emitting body which can reduce color variation by one injection | pouring and hardening | curing of fluorescent substance mixing resin can be provided.

  As shown in FIG. 2A, the light emitter of the present invention includes a cup-shaped member 11 having a bowl-shaped recess, a light-emitting element 12 mounted on the bottom surface of the cup-shaped member 11, and a cup-shaped member 11. In the luminous body 10 composed of the transparent resin portion 13 filled in the recess, at least two types of phosphors 15 and 16 having different fluorescence wavelengths are mixed in the transparent resin portion 13. The ratio between the phosphors 15 and 16 of the particle size squared density value of each phosphor is 10 or less.

The light emitting element 12 is an LED element that emits light in a wavelength region of at least a part of blue light to ultraviolet light, for example, any LED element selected from a blue LED element, a purple LED element, and a near ultraviolet LED element. be able to.
As the transparent resin 13, for example, a transparent silicone resin or the like can be used.
As the phosphors 15 and 16, fine particle phosphors that convert the wavelength of light from the light emitting element 12 and emit blue, green, yellow, or red light can be used.

  In the light emitter 10 of the present embodiment, the phosphors 15 and 16 are combined so that the ratio between the phosphors of the squared particle size × density value is 10 or less. The bodies 15 and 16 are present almost uniformly in the transparent resin layer 13, and color variation at the time of light emission of the light emitter can be reduced. When the ratio between the phosphors exceeds 10, as shown in FIG. 2B, one phosphor 16 settles faster in the transparent resin before curing than the other phosphor 15, and these fluorescences. Since the bodies 15 and 16 are separated in the recess depth H direction and are present in the cured resin, the color variation of the light emitting body 10 occurs, which is not preferable.

  At the time when the mixed material in which the phosphors 15 and 16 are mixed with the transparent resin is poured into the concave portion of the cup-shaped member 11, the concentration of the phosphors 15 and 16 can be reduced and the filling can be performed. It has been found that when the time (time until the resin is cured) exceeds a certain limit, the color variation increases. In particular, in the case of manufacturing by repeating the method of pouring a mixed material in which the transparent resin and the phosphors 15 and 16 are mixed into the concave portion of the cup-shaped member 11 little by little in a batch type, the variation is between the first half and the second half in the batch. I found it different.

  These variations were found to occur due to the different densities and particle sizes of the respective phosphors. FIG. 2A is a schematic view immediately after the mixed material of the transparent resin and the phosphors 15 and 16 is poured into the concave portion of the cup-shaped member 11, and FIG. 2B is a diagram in which the mixed material is poured. It is a schematic diagram of the state left to stand. Here, a case where the particle diameter of the second phosphor 16 is larger than that of the first phosphor 15 is shown. Thus, the phosphor 16 having a large particle size or high density is collected after pouring the mixed material and is left standing (it takes time until it is cured), so that the phosphor 16 gathers in the lower part of the concave portion of the cup-shaped member. .

In order to suppress such particles having a large particle size or a high density from being collected in the lower part, it is possible to prevent the particles from being hardened immediately after pouring the mixed material. However, in general, a batch type in which cup-shaped members are gathered in units of several tens to several hundred pieces and the mixed material is poured and then cured is adopted, so after pouring the mixed material Continuous curing one by one has the problem that a new apparatus is required and costs increase.
In addition, since it takes time to attach and detach the cup-shaped member to and from the apparatus, the number of LEDs that can be manufactured per unit time is reduced, and the cost is inevitably high. Thus, the method of curing immediately after pouring the mixed material can be expected to reduce the color variation, but there is a problem that a new apparatus is required and the cost is increased due to inferior productivity.
Also, by making the viscosity of the transparent resin very high, it is possible to prevent particles having a large particle size or high density from being collected in the lower part, but if the viscosity is high, a phosphor is added to the resin. It becomes very difficult to mix evenly. For example, when mixing phosphors, a method in which the viscosity is kept low and then the viscosity is increased by a method such as heat treatment is poured into the cup-shaped member. When the viscosity is high at the time of pouring into the member, there arises a problem in terms of reliability such as entrainment of bubbles, and a resin does not flow to the boundary between the cup-shaped member and the light emitting element, leaving a void. Of course, in order to flow a resin having a viscosity higher than that of the resin used so far into the cup-shaped member, there arises a problem that a new device is required and costs are increased.
In order to suppress this separation by a method that does not increase the cost and does not have a problem of reliability as described above, particles of phosphors having a high density (generally inorganic phosphors) are required. This can be reduced by reducing the diameter and increasing the particle diameter of the phosphor having a low density, and this can reduce the color variation of the light emitter to some extent.
Further investigations have shown that the color variation can be further reduced by reducing the difference between the square of the particle diameter of each phosphor and the density of the phosphor within 10 times. .

  In addition to the above methods, for example, in order to increase productivity, a batch type (a mixture of transparent resin and phosphor is poured into the concave portion of the cup-shaped member little by little, and a plurality of cup-shaped members are cured together. In the case of using the manufacturing method (1), a difference in color occurs between the one poured into the first and the last of the batch because the standing time is different. This is because the state of the phosphor in the recess of the cup-shaped member changes due to the difference in the standing time. For example, if FIG. 2 (a) is in the last state of the batch, the first one in the batch will be in the state as shown in FIG. 2 (b). This is because the last material poured in is that all the phosphor is deposited at the bottom as shown in FIG.

As a countermeasure, the most moving phosphor (the particle size is large and the density is high) of the phosphor to be used changes its state most due to the difference in the leaving time. By determining the limit, it is possible to keep the color variation within a predetermined range.
As a result of repeated studies, it was found that the color variation can be greatly reduced by setting the moving amount of the most moving phosphor within 20% of the depth of the cup-shaped member recess. In other words, as shown in FIG. 3A, the phosphor 17 is above the depth h (h = 0.8 × H) that is 80% of the recess depth H of the cup-shaped member 11 into which the mixed material has been poured. It must be cured while in the part.

  The reason why the amount of movement is defined not by the numerical value but by the depth of the concave portion of the cup-shaped member is that the moving speed changes depending on the density and the particle size. The change in the emission color of the illuminant 10 is because the amount of movement also changes when the recess depth H changes, as a result of examination.

If the density of the phosphor to be used is known, the particle diameter of the phosphor is changed accordingly (the range is to make the ratio of the square of the phosphor particle diameter to the density within 10 times). Color variation can be reduced.
In general, it is necessary to make hundreds to thousands of prototypes just by examining the degree of color variation, and since there are large variations in color, studies to reduce this result in several times as many prototypes. Necessary. According to the present invention, it is possible to significantly reduce the time and cost required for trial production.

  As for the density of the phosphor, for example, there is a method of changing the apparent density by granulating the phosphor (making a small powder into particles) or coating it with a low density.

  Furthermore, in a normal manufacturing method, a standing time (a time from pouring the mixture of the tree phosphor into the concave portion until it is cured) occurs, but if the particle size to be used is large (the density is high), the standing time is left. If the time is shortened (the amount of one batch is small) and the particle size is small (the density is low), it is possible to lengthen the standing time, and there is no waste of time spent on one batch time, and productivity is improved. improves.

  On the contrary, when the time for one batch is determined, for example, when a plurality of cup upper members are connected by a frame and divided after pouring the phosphor-containing resin, or when the phosphor used changes This is very effective in reducing trial production time and trial production costs.

[Example 1]
A prototype was made using a surface mount package as shown in FIG. As the transparent resin, Shin-Etsu Chemical's silicone resin for LEDs (KJR-9022) was used. A blue LED element was used as the light-emitting element, and a white light-emitting body was produced using blue LED + green phosphor + yellow phosphor.
Alpha sialon and beta sialon were used as phosphors. These phosphors are known materials.
Alphasialon yellow phosphor ・ Patent No. 3668770 “Oxynitride phosphor activated by rare earth elements”
・ Rong-Jun Xie et al., Appl. Phys. Lett., Vol.84, pp.5404-5406
Beta Sialon Green Phosphor ・ Naoto Hirosaki et al., Appl. Phys. Lett., Vol.86, 211905

  As a manufacturing procedure, in the first step, the light emitting element was die-bonded to the package electrode (for element mounting) using a conductive paste. In the second step, the light emitting diode element and the other package electrode were wire-bonded with a fine gold wire. In the third step, a resin in which the phosphor powder is mixed and dispersed is dropped into a concave portion of the package with a dispenser or the like so as to cover the light emitting element and the fine gold wire, and the resin is cured in an oven.

In this third step, the color variation of each of the two types of phosphors was examined by changing the ratio of the square of the particle diameter to the density. Since the density of alpha sialon and beta sialon was almost equal, about 3.2 g / cm ³ , the particle size was varied. As a method of aligning the particle diameter, screening was performed, and measurement was performed using a CILAS particle size meter Model 1064 (measurement condition Standard L). The particle size described below is d50 (weight median particle size) measured with a particle size meter. In this survey, the particle size of alpha sialon was changed.
The standard deviation when the ratio is changed based on the standard deviation of chromaticity x and y when the ratio of the square of the particle size of the two phosphors to the density is 1 as an index representing the color variation Was used. The results are shown in Table 1.

Moreover, in order to investigate the case where a density changed, the case where P46Y3 yellow fluorescent substance (density about 4.6 g / cm < ³ >) marketed from Kasei Optonics Co., Ltd. and beta sialon green fluorescent substance was used was also investigated. In this case, the particle size of the beta sialon green phosphor was changed. In this case as well, the ratio was changed with reference to the standard deviation of chromaticity x and y when the ratio of the square of the particle size of the two types of phosphors to the density is 1, as an index representing the color variation. When the standard deviation change was used. The results are shown in Table 2.

  From Table 1 and Table 2, it can be seen that if the ratio of the squared particle size x density of the two types of phosphors is 10 or less, the color variation becomes small.

[Example 2]
The transparent resin used was a silicone resin for LED (KJR-9022) manufactured by Shin-Etsu Chemical, and alpha sialon and beta sialon were used for the phosphor. First, the amount of movement and the standing time of the phosphor having a changed particle size were examined in advance. This makes a mixed material in which a fluorescent material is mixed with a transparent resin, and flows the mixture into a cup-shaped member to be mixed. Thereafter, the standing time is changed and heat-cured. The cured resin was cut in half together with the cup-shaped member, and the amount of movement of the phosphor was investigated.
In addition, since the amount of movement changes depending on the viscosity of the resin, the room temperature was adjusted. Moreover, the elapsed time after mixing the main material of a transparent resin and a hardening | curing agent is match | combined in the range in which a viscosity does not change a lot. Next, white light emitters were prepared in the same manner as in Example 1, and the relationship between the standing time after pouring these resins and the color variation was examined. Two types of packages having different depths (package 1 having a recess depth of 0.6 mm and package 2 having a recess depth of 1.0 mm) were examined, and the results are shown in Table 3. Since the color variation is smaller when the leaving time is shorter, the reference for the change in chromaticity is 0.05.

  From Table 3, it was found that if the amount of movement of the phosphor is within the recess depth ratio of 0.2, the color variation of the phosphor is small.

It is sectional drawing which shows the structure of a common light-emitting body. An example of the method for producing a light emitter according to the present invention is shown in the case of curing immediately after filling a mixture of two kinds of phosphors and a transparent resin in the recess (a), and because it was left after filling with the mixture It is sectional drawing which shows the structure of the light-emitting body obtained by making it harden | cure after non-uniform sedimentation of fluorescent substance arises. Another example of the method for manufacturing a light emitter according to the present invention is shown, in which the phosphor is not recessed to the depth h (80) of the recess depth H (a), and the phosphor has a recess depth. It is sectional drawing which shows the structure of the light-emitting body obtained by (b) when resin is hardened after settling below the depth h of 80% of depth H.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Luminescent body, 11 ... Cup-shaped member, 12 ... Light emitting element, 13 ... Transparent resin part, 14, 15, 16, 17 ... Phosphor.

Claims (7)

A light-emitting element that emits light in a wavelength range of at least a part of blue light to ultraviolet light, a cup-shaped member that surrounds the light-emitting element, and a transparent material in which a phosphor filled in the concave portion of the cup-shaped member is mixed A phosphor that excites the phosphor by the light from the light emitting element and emits the mixed color light of the light from the light emitting element and the fluorescence emitted from the phosphor or the fluorescence emitted from the phosphor to the outside. There,
At least two types of phosphors having different fluorescence wavelengths are mixed in the transparent resin portion, and the ratio between the phosphors, which is the square of the particle size of each phosphor × density value, is 10 or less. A light emitter characterized by the following.   2. The light emitting body according to claim 1, wherein an apparent density of at least one phosphor is changed.   The phosphor according to claim 1 or 2, wherein all the phosphors used are present in a portion above 80% of the cup depth. A light emitting element that emits light in at least a part of the wavelength range of blue light to ultraviolet light is mounted in the concave portion of the cup-shaped member, and then at least two kinds of phosphors having different fluorescence wavelengths are mixed in the concave portion. A manufacturing method for obtaining a light emitter by filling a transparent resin and curing it,
1 is a mixture of transparent resin and at least two kinds of phosphors having different fluorescence wavelengths and the ratio of the square of the particle size of each phosphor to the value of density is 10 or less. A method of manufacturing a light emitter, wherein the recess is filled by a single coating operation.   At least two types of the time required for curing after filling the concave portion of the cup-shaped member with the moving amount of the phosphor having the largest moving amount within 20% of the concave portion depth among the phosphors to be used. The phosphor according to claim 4, wherein the phosphor is filled by a single coating operation.   It is characterized in that at least two or more types of phosphors having a predetermined time until curing after being filled with a mixed material in a cup-shaped member are applied by a single coating operation based on the particle size and density of the phosphor to be used. The manufacturing method of the light-emitting body according to claim 5. 6. The method of manufacturing a luminescent material according to claim 5, wherein at least two or more types of phosphors having a determined particle size and density of the phosphor to be used due to limitation of the standing time are applied by a single coating operation.

Images