JP2005340512A - Light emitting device and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the change of chrominance caused by the azimuth of light emission in a light emitting device. <P>SOLUTION: First resin 6 is applied so as to be recessed so that blue light emitting diode elements 4 can be covered in a cup 21, the external end can be set at the lower position of the uppermost part of the internal wall face of the cup 21, and the central part can be set at the lower position of the external end. Second resin 7 to which a phosphor 8 is distributed is applied so that the second resin is set at the upper part of the first resin 6 in the cap 21, the whole upper surface of the first resin 6 can be sealed by the lower face, and the position of the upper face can be made higher than the uppermost part of the internal wall face of the cap 21. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light emitting device such as a white light emitting diode and a method for manufacturing the light emitting device.

  Conventionally, blue light-emitting diode elements that emit light at a short wavelength such as blue and excited by absorbing part or all of the light emitted from the blue light-emitting diode elements, and emit fluorescence of longer wavelengths such as yellow. There are white light emitting diodes using fluorescent materials.

  As an example of the above white light emitting diode, a white color composed of a compound semiconductor blue light emitting diode element and a cerium activated yttrium / aluminum / garnet fluorescent material which absorbs blue light and emits yellow fluorescence which is a complementary color of blue. A light emitting diode is mentioned (for example, refer patent document 1).

Next, the configuration of the conventional white light emitting diode as described above will be described.
As shown in FIGS. 3 and 4, the white light emitting diodes 101a and 101b include lead wires 102 and 103, a blue light emitting diode element 104, a bonding wire 105, a first resin 106, a phosphor 107, 2 resin 108.

  The lead wire 102 is provided with a recess, on which the blue light emitting diode element 104 is placed.

  The blue light emitting diode element 104 and the lead wires 102 and 103 are electrically connected by a bonding wire 105 made of gold or a conductive paste (not shown).

  A fluorescent material 107 is dispersed in the first resin 106 and covers the blue light emitting diode element 104.

  The second resin 108 seals the upper portions of the lead wires 102 and 103, the bonding wire 105, and the first resin 106.

That is, the fluorescent material 107 is dispersed only in the vicinity of the blue light emitting diode element 104.
Japanese Patent No. 2927279

  However, in the white light emitting diodes 101a and 101b as described above, the chromaticity may change depending on the light emitting direction.

  As also mentioned in Japanese Patent No. 3065258, the blue component is strong in the center as viewed from the front of the white light emitting diode, the chromaticity changes concentrically as it goes to the periphery, and the yellow component in the periphery. Becomes stronger.

  Further, as a comparative example, a white light emitting diode similar to that shown in FIG. 3 was actually manufactured, and a current of 20 mA was passed. As a result, the entire chromaticity coordinate (x, y) in the CIE XYZ color system was obtained. As (0.31, 0.29), white color was shown, but the blue component was strong in the central part and the yellow component was strong in the peripheral part.

  These chromaticities are points on a straight line connecting the chromaticity coordinates of the blue light-emitting diode element and the chromaticity coordinates of the luminescent color of the fluorescent material on the chromaticity diagram of the XYZ color system. As a result of measuring the chromaticity only in the vicinity, the distance on the chromaticity diagram was shifted 0.03 to the blue side as compared with the case of measuring the entire chromaticity.

  In this comparative example, a blue light emitting diode element having an emission center wavelength of 460 nm was used, and a yttrium aluminum garnet (YAG) powder fluorescent material activated with cerium was used as the fluorescent material. . Moreover, the epoxy resin was used for resin.

  Japanese Patent No. 3605258 solves the above problem by providing an accommodating portion on which an LED (light emitting diode) chip and a coating portion having a fluorescent material are stacked independently of the reflecting portion. However, in the light emitting diode shown in FIG. 3B of Japanese Patent No. 3605258, a blue light emitting diode element is die-bonded in a storage portion having a narrow opening width and a deep depth, and a resin in which a fluorescent material is dispersed is used. Since it will be applied, there is a problem that the technical difficulty of the mounting process increases.

  In addition, since the light emitted from the side surface of the blue light-emitting diode element reaches the outside of the storage portion through many reflections, it is unavoidable to reduce the reflection efficiency, in other words, the light extraction efficiency.

  In view of such circumstances, the present invention manufactures a light emitting device in which a change in chromaticity due to a light emitting direction is suppressed, and a light emitting device in which fine adjustment of the chromaticity can be easily and accurately performed and a change in chromaticity due to a light emitting direction is suppressed. An object of the present invention is to provide a method for manufacturing a light emitting device.

  The present invention according to claim 1 includes at least two electrode terminals, a semiconductor light emitting element that is electrically connected to the electrode terminals and emits light having a wavelength in an ultraviolet wavelength region, a blue-violet wavelength region, or a blue wavelength region. A cup portion on which the semiconductor light emitting element is mounted, and has translucency, covers the semiconductor light emitting element in the cup portion, and the outer edge portion is at a position lower than the uppermost portion of the inner wall surface of the cup portion, The first resin applied so that the portion is in a concave shape at a position lower than the outer edge portion, and translucent, in the upper portion of the first resin in the cup portion, the lower surface of the first resin And the second resin applied so that the position of the upper surface is higher than the uppermost portion of the inner wall surface of the cup portion, and dispersed in the second resin. Absorbs at least part of the light emitted from the element and is visible A fluorescent material that emits longer-wavelength fluorescence in a long range, a light-transmitting at least part of an electrode portion, a cup portion, a first resin that covers a semiconductor light emitting element, and a fluorescent material are dispersed. And a third resin that covers the second resin.

  According to a second aspect of the present invention, in the invention of the first aspect, the electrode terminal is a lead wire, the cup portion is a member having a recess formed in at least one of the lead wires, The gist of the shape of the resin is a shell type.

  According to a third aspect of the present invention, the semiconductor light emitting device is a blue light emitting diode device that emits blue light, and the fluorescent material is a material that absorbs part of the blue light and emits yellow fluorescence, and emits blue light. The gist of the invention is to emit white light by mixing the blue light emitted from the diode element and the yellow fluorescence emitted from the fluorescent material.

  The present invention according to claim 4 is equipped with at least two electrode terminals, a semiconductor light emitting element that emits light having a wavelength in an ultraviolet wavelength region, a blue-violet wavelength region, or a blue wavelength region, and a semiconductor light emitting device. A cup, a fluorescent material that absorbs at least part of light emitted from the semiconductor light emitting element and emits longer wavelength fluorescence in the visible wavelength range, a first resin having translucency, and a translucency A light emitting device comprising: a second resin having a fluorescent material dispersed therein; and a third resin having translucency, wherein the semiconductor light emitting element is fixed to the cup portion. A step of electrically connecting the electrode terminal and the first resin, the first resin covers the semiconductor light emitting element in the cup portion, and the outer edge portion is at a position lower than the uppermost portion of the inner wall surface of the cup portion, A concave shape in which the part is lower than the outer edge part and The first resin curing step of curing the first resin and the second resin is applied to the upper portion of the first resin in the cup portion, and the lower surface thereof is the entire upper surface of the first resin. Is applied so that the position of the upper surface is higher than the uppermost part of the inner wall surface of the cup part, and the second resin is cured, and the third resin causes at least the electrode part to be cured. The gist of the present invention is to have a coating step of coating a part, a cup, a first resin coated with a semiconductor light emitting element, and a second resin in which a fluorescent material is dispersed.

  According to a fifth aspect of the present invention, in the invention according to the fourth aspect, in the second resin curing step, the semiconductor light emitting element is caused to emit light after the first resin is cured, and the chromaticity of the emitted light is measured. However, the gist is to apply the second resin in which the fluorescent substance is dispersed in a small amount in a plurality of times, and to finish the application of the second resin when the appropriate chromaticity is obtained.

  According to a sixth aspect of the present invention, in the invention according to the fourth aspect, in the second resin curing step, after the first resin is cured, the semiconductor light emitting element emits light, and the intensity of the emitted light is measured. The gist is to determine the coating amount of the second resin on the basis of the measurement result and a relational expression or a numerical table determined based on the light emission intensity of the semiconductor light emitting element measured in advance.

  According to a seventh aspect of the present invention, in the invention according to any one of the fourth to sixth aspects, the electrode terminal is a lead wire, and the cup portion has a recess formed in at least one of the lead wires. The shape of the third resin is bullet-shaped.

  According to an eighth aspect of the present invention, in the semiconductor device according to any one of the fourth to seventh aspects, the semiconductor light emitting element is a blue light emitting diode element that emits blue light, and the fluorescent material is one of blue light. This substance is a substance that absorbs a portion and emits yellow fluorescence, and its gist is that white light is emitted by a mixture of blue light emitted from a blue light emitting diode element and yellow fluorescence emitted from a fluorescent substance.

  According to the present invention, a light emitting device in which a change in chromaticity due to a light emitting direction is suppressed, and a light emitting device in which fine adjustment of chromaticity can be easily and accurately performed, and a change in chromaticity and a variation in chromaticity due to the light emitting direction are suppressed. A light emitting device manufacturing method that can be manufactured can be realized.

Hereinafter, the light-emitting device and the light-emitting device manufacturing method of the present invention will be described with reference to the drawings.
The following examples are only for the purpose of explaining the present invention and do not limit the scope of the present invention. Accordingly, those skilled in the art can employ various embodiments including each or all of these elements, and these embodiments are also included in the scope of the present invention.
Further, in all drawings for explaining the following embodiments, the same reference numerals are given to the same elements, and repeated explanation thereof is omitted.

FIG. 1 is a cross-sectional view of a white light-emitting diode (light-emitting device) 1 according to a first embodiment (Example 1) of the present invention, and FIG. 2 is a perspective view of the white light-emitting diode 1.
The white light emitting diode 1 has a substantially cylindrical shape with a curved upper part, in other words, a shape similar to a shell, and is made of lead wires 2 and 3 as electrode terminals, a blue light emitting diode element 4 as a semiconductor light emitting element, and gold The bonding wire 5 and the fluorescent material 8 are each made of a first resin 6, a second resin 7 and a third resin 9 having translucency, and the lower portions of the lead wires 2 and 3 are exposed to the outside. Yes.

  The upper end portion of the lead wire 2 is provided with a cup portion 21 having a recess, on which the blue light emitting diode element 4 is placed.

  The blue light-emitting diode element 4 is provided with one electrode on the upper surface (the surface on the bonding wire 5 side) and another electrode on the lower surface (the surface on the concave side of the lead wire 2) (both not shown). The electrode on the upper surface and the lead wire 3 are electrically connected by the bonding wire 5, and the electrode on the lower surface and the lead wire 2 are electrically connected by die bonding using a conductive paste or the like.

  Further, the first resin 6 covers the blue light emitting diode element 4 in the cup portion 21, and the outer edge portion thereof is at a position lower than the uppermost portion of the inner wall surface of the cup portion 21, and the center portion thereof is the outer edge. It is apply | coated so that it may become a concave shape in a position lower than a part.

  In addition, the fluorescent material 8 is dispersed in the second resin 7, and is located above the first resin 6 in the cup portion 21, and its lower surface seals the entire upper surface of the first resin 6. The upper surface is applied so that the position of the upper surface is higher than the uppermost portion of the inner wall surface of the cup portion 21.

  The third resin 9 includes a part of the lead wires 2 and 3, the cup portion 21, the first resin 6 covering the blue light emitting diode element 4, and the second resin in which the fluorescent material 8 is dispersed. 7 is coated (sealed).

  In this embodiment, an epoxy resin is used as the first resin 6, the second resin 7, and the third resin 9.

  The blue light emitting diode element 4 emits blue light having a wavelength of 460 nm, and the fluorescent material 8 absorbs a part of the light and is excited thereby to emit yellow fluorescence that is a complementary color of blue.

  The fluorescent material 8 is a powdery YAG-based fluorescent material activated with cerium, and its emission center wavelength is about 563 nm.

  The yellow fluorescence is mixed with blue light that is not absorbed by the fluorescent material 8, and as a result, white light is emitted.

Next, the manufacturing method of said white light emitting diode 1 is demonstrated.
First, in the first step, the blue light emitting diode element 4 is die-bonded to a recess (cup portion 21) in one of the lead wires 2 and 3 (in this embodiment, the lead wire 2) with a conductive paste.

  In the second step, the blue light emitting diode element 4 and the other lead wire (in this embodiment, the lead wire 3) are wire-bonded by the bonding wire 5.

  In the third step, an appropriate amount of the first resin 6 is applied to the cup portion 21, thereby covering the blue light emitting diode element 4, and the first resin 6 is cured. At this time, as the first resin 6, a resin having a sufficiently high wettability in relation to the inner wall surface of the cup portion 21 is used, and the coating amount is the volume of the concave portion of the cup portion 21 (from the blue light emitting diode element 4. The dispenser of the first resin 6 is adjusted so that it is slightly less than the remainder of the volume (subtracting the volume), and after curing, its outer edge is lower than the uppermost part of the inner wall surface of the cup part 21, and its center A part is made into the concave shape in a position lower than an outer edge part.

  In the fourth step, an appropriate amount of the second resin 7 in which 40% by weight of the powdered fluorescent material 8 is dispersed is applied on the first resin 6 and cured.

  The shape of the lower part of the second resin 7 is determined by the concave shape when the first resin 6 is cured, and the shape of the upper part is determined by factors such as the surface tension and the curing shrinkage rate of the second resin 7.

  In addition, by appropriately controlling the amount of the first resin 6 and the amount of the second resin 7, it is possible to make the thickness of the second resin 7 containing the fluorescent substance 8 substantially uniform, Further, it is thick at the center and thin at the periphery, that is, as described above, the lower surface seals the entire upper surface of the first resin 6, and the position of the upper surface is higher than the uppermost portion of the inner wall surface of the cup portion 21. It is also possible to be.

  In addition, the prototype is repeated by using three parameters, that is, the amount of the first resin 6 and the amount of the second resin 7, and the ratio of the fluorescent material 8 in the second resin 7, as necessary. It is possible to obtain an optimum condition in which the change in color is minimal and the result of color mixing is just white.

  The fifth step is a casting step, in which part of the lead wires 2 and 3, the bonding wire 5, the cup portion 21, the first resin 6 covering the blue light emitting diode element 4, and the fluorescent material The second resin 7 in which 8 is dispersed is coated (sealed) with the third resin and cured.

  In addition, the lead wires 2 and 3 can be manufactured integrally. In this case, the lead wires 2 and 3 have a shape connected at the lower portion thereof, and are thus manufactured integrally. In using the lead wires, after the step 4, a portion for connecting the lead wires 2 and 3 is removed, and a sixth step is performed in which the lead wires 2 and 3 are separate members.

  When the white light emitting diode 1 of FIG. 1 was manufactured through the above steps, the change in chromaticity due to the light emitting direction was suppressed and an improvement was seen as compared with the white light emitting diode 101a shown in FIG. Although variations in chromaticity existed, the prototypes all improved the difference between the overall chromaticity and the chromaticity near the center as compared with the white light emitting diode 101a.

The white light emitting diode (light emitting device) manufacturing method according to the second embodiment (Example 2) of the present invention will be described below.
In white light emitting diodes using blue light emitting diode elements and blue absorbing yellow light emitting phosphors, variations in chromaticity at the time of manufacture have also been a problem.

  In order to solve this problem, for example, in Japanese Patent Application Laid-Open No. 2002-344029, after a fluorescent layer containing a fluorescent agent is provided on a light-transmitting sealing resin in which a light emitting diode element is sealed, the fluorescent layer is laser-bonded. A technique for adjusting the color tone of a luminescent color by cutting it later by beam processing is disclosed.

  In Japanese Patent Laid-Open No. 2002-344029, physical processing such as laser processing, electron beam processing, ion beam processing, ion etching, sputter etching, and plasma etching is desirable, but any of these requires additional expensive processing equipment. .

  On the other hand, the white light emitting diode manufacturing method according to this embodiment can adjust the chromaticity without requiring additional processing equipment.

  Specifically, when the second resin 7 is applied, the second resin 7 is applied several times in small amounts. In this case, the integrally formed lead wire is not cut later, but a pair of lead wires separated and electrically insulated in advance is used.

  Further, since the positions of the lead wires 2 and 3 need to be fixed so that the bonding wire 5 is not cut, an insulating jig is used.

  Further, when the curing of the first resin 6 is completed, the blue light-emitting diode element 4 is in an energizable state, and is energized to light it before applying the second resin 7.

  Next, a light receiver of a chromaticity meter is installed above, and the second resin 7 is applied in small amounts over several times while measuring the chromaticity of the light emitted from the blue light emitting diode element 4. Then, when the appropriate chromaticity is reached, the coating is terminated, and at the same time, the energization to the blue light emitting diode element 4 is terminated, and the second resin 7 is cured.

  Through such a process, the chromaticity of the white light emitting diode can be adjusted without additionally introducing expensive physical processing equipment.

Hereinafter, a method for manufacturing a white light emitting diode (light emitting device) according to a third embodiment (Example 3) of the present invention will be described.
In the previous Example 2, since the application of the second resin 7 requires a certain amount of time, when the white light emitting diode 1 is manufactured in large quantities, the application operation of the second resin 7 is performed only once. Even better if you can.

  One of the main causes of chromaticity variation in the manufacturing stage is a variation in emission intensity of the blue light emitting diode element 4.

  Therefore, it is desirable that the application of the second resin 7 is performed only once rather than a plurality of times, and that chromaticity adjustment is possible in the manufacturing stage.

  In the present embodiment, in order to satisfy the above points, after the blue light emitting diode element 4 is turned on, the intensity (light emission intensity) of the light emitted from the blue light emitting diode element 4 is measured by the light receiver above it. The coating amount of the second resin 7 is determined based on the above.

  More specifically, the relationship between the light emission intensity of the blue light-emitting diode element 4 and the chromaticity of the light emitted from the blue light-emitting diode element 4 and the coating amount of the second resin 7 is similar to that of the second embodiment. It is possible to obtain in advance.

  That is, the intensity of light emitted from the blue light emitting diode element 4 is measured, and based on the measurement result and a relational expression or numerical table determined based on the light emission intensity of the blue light emitting diode element 4 measured in advance. Then, the coating amount of the second resin 7 is determined.

  As a result, the variation in emission intensity that causes the variation in chromaticity can be made uniform, and an appropriate chromaticity can be obtained by a single coating operation. Therefore, the manufacturing efficiency is improved as compared with Example 2.

  In the above embodiment, the case where the electrode terminals are the lead wires 2 and 3 has been shown. However, the present invention is not limited to this, and various electrode terminals can be used. 4 may be electrically connected.

  In addition, the present invention is not limited to the white light emitting diodes shown in the above embodiments, and is excited by absorbing a light emitting diode element that emits light of a short wavelength and a part or all of the light emitted from the light emitting diode element. In general, any light emitting diode using a fluorescent material that emits longer wavelength fluorescence can be applied.

  For example, the present invention can be applied to a blue light emitting diode, a green light emitting diode, a red light emitting diode, a white light emitting diode, and the like using an ultraviolet light emitting diode element and an ultraviolet excited visible light emitting fluorescent material.

  The present invention can also be applied to a light emitting diode having three or more bonding wires.

As described above, according to the present invention, in a light emitting device such as a white light emitting diode, a change in chromaticity due to a light emitting direction can be suppressed.
Further, it is possible to adjust the chromaticity when manufacturing a light emitting device such as a white light emitting diode.

  Further, even if the semiconductor light emitting element such as a blue light emitting diode element has a variation in emission wavelength or emission intensity, the chromaticity of a light emitting device such as a white light emitting diode using the same can be made uniform.

It is sectional drawing which shows the light-emitting device (white light emitting diode) which concerns on 1st Example of this invention. It is a perspective view of the light-emitting device shown in FIG. It is sectional drawing which shows the conventional white light emitting diode. It is sectional drawing which shows another example of the conventional white light emitting diode.

Explanation of symbols

1 Light emitting device (white light emitting diode)
2, 3 Lead wire 4 Blue light emitting diode element 5 Bonding wire 6 First resin 7 Second resin 8 Fluorescent substance 9 Third resin 101a, 101b Conventional white light emitting diode 102, 103 Lead wire 104 in conventional example 104 Conventional example Light-emitting diode element in 105 Bonding wire in conventional example 106 First resin in conventional example 107 Fluorescent substance in conventional example 108 Second resin in conventional example

Claims (8)

At least two electrode terminals;
A semiconductor light emitting element that is electrically connected to the electrode terminal and emits light having a wavelength in an ultraviolet wavelength region, a blue-violet wavelength region, or a blue wavelength region;
A cup portion on which the semiconductor light emitting element is mounted;
It has translucency, covers the semiconductor light emitting element in the cup portion, and its outer edge portion is at a position lower than the uppermost portion of the inner wall surface of the cup portion, and its center portion is at a position lower than the outer edge portion. A first resin applied to form a concave shape;
It has translucency, is in the upper part of the first resin in the cup part, its lower surface seals the entire upper surface of the first resin, and the position of the upper surface is the inner wall surface of the cup part A second resin applied to be higher than the uppermost portion of
A fluorescent material that is dispersed in the second resin, absorbs at least part of the light emitted from the semiconductor light emitting element, and emits longer wavelength fluorescence in the visible wavelength range;
Covers at least a part of the electrode part, the cup part, the first resin covering the semiconductor light emitting element, and the second resin in which the fluorescent material is dispersed. A light emitting device comprising: a third resin. The electrode terminal is a lead wire,
The cup part is a member having a recess formed in at least one of the lead wires,
The light emitting device according to claim 1, wherein the shape of the third resin is a cannonball shape. The semiconductor light emitting element is a blue light emitting diode element that emits blue light,
The fluorescent substance is a substance that absorbs a part of the blue light and emits yellow fluorescence,
3. The light emitting device according to claim 1, wherein white light is emitted by a color mixture of the blue light emitted from the blue light emitting diode element and the yellow fluorescence emitted from the fluorescent material. From at least two electrode terminals, a semiconductor light emitting element that emits light having a wavelength in the ultraviolet wavelength region, blue violet wavelength region, or blue wavelength region, a cup portion on which the semiconductor light emitting device is mounted, and the semiconductor light emitting device A fluorescent material that absorbs at least part of the emitted light and emits longer-wavelength fluorescence in the visible wavelength range; a first resin having translucency; and a translucent material, A method of manufacturing a light emitting device comprising a dispersed second resin and a translucent third resin,
Fixing the semiconductor light emitting element to the cup portion and electrically connecting the semiconductor light emitting element and the electrode terminal;
The first resin covers the semiconductor light emitting element in the cup portion, and the outer edge portion is at a position lower than the uppermost portion of the inner wall surface of the cup portion, and the center portion is at a position lower than the outer edge portion. A first resin curing step of applying a certain concave shape and curing the first resin;
The second resin is located on the upper portion of the first resin in the cup portion, the lower surface seals the entire upper surface of the first resin, and the position of the upper surface is the inner wall surface of the cup portion. A second resin curing step of applying the resin so as to be higher than the uppermost portion of the resin, and curing the second resin;
The third resin covers at least a part of the electrode part, the cup part, the first resin covering the semiconductor light emitting element, and the second resin in which the fluorescent material is dispersed. A light emitting device manufacturing method comprising: a covering step.   In the second resin curing step, after the first resin is cured, the semiconductor light emitting element emits light, and the second resin in which the fluorescent material is dispersed is measured while measuring the chromaticity of the emitted light. 5. The method for manufacturing a light emitting device according to claim 4, wherein the application is performed in a plurality of times, and the application of the second resin is terminated when the appropriate chromaticity is achieved.   In the second resin curing step, after the first resin is cured, the semiconductor light emitting device emits light, the intensity of the emitted light is measured, and the measurement result and the light emission of the semiconductor light emitting device measured in advance are measured. The light emitting device manufacturing method according to claim 4, wherein the coating amount of the second resin is determined based on a relational expression or a numerical table determined based on the strength. The electrode terminal is a lead wire,
The cup part is a member having a recess formed in at least one of the lead wires,
The method for manufacturing a light-emitting device according to claim 4, wherein the shape of the third resin is a cannonball shape. The semiconductor light emitting element is a blue light emitting diode element that emits blue light,
The fluorescent substance is a substance that absorbs a part of the blue light and emits yellow fluorescence,
8. The white light is emitted by a color mixture of the blue light emitted from the blue light emitting diode element and the yellow fluorescence emitted from the fluorescent material. 8. Light emitting device manufacturing method.

Images