JP2002111070A - Reflective light-emitting diode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep an external radiation efficiency at a high level even if a reflective light-emitting diode is downsized. SOLUTION: Related to a reflective light-emitting diode 1, leads 3a, 3b, and 4 which supply an electric power to a light-emitting element 2 are sealed with a transparent epoxy resin 6, and a reflective surface form is molded on a light- emitting surface side of the light-emitting element 2 while a form of radiation surface 7 is molded on a rear surface side with a metal vapor-deposited on the reflective surface to form a reflective mirror 5. The reflective surface has a symmetrical shape rotating a part of an oval about a center axis where a position of the light-emitting element 2 being a primary focal point while a point f1 being a secondary focal point is rotated around the center axis of the reflective LED 1. The light reflective on the reflective mirror 5 after emitted from the light-emitting element 2 is converted toward a circle 8 passing the point f1, so even if the area ratio of the light-emitting element 2 increases, the light-emitting element 2 does not shield the light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type light emitting diode (hereinafter also abbreviated as "reflection type LED") for reflecting light emitted from a light emitting element with a concave reflector made of metal or the like.
It is about. In this specification, the LED chip itself is called a “light emitting element”, and the entire light emitting device on which the LED chip is mounted is referred to as a “light emitting diode” or “LE”.
D ".

[0002]

2. Description of the Related Art Conventionally, a reflection type LED in which a lead on which a light emitting element is mounted is sealed with a resin, a reflecting surface shape is formed on a light emitting surface side of the light emitting element, and a radiation surface shape is formed on a back side of the light emitting element. It has been devised. In this LED,
The reflecting mirror is formed by performing metal evaporation on the resin surface formed into the reflecting surface shape. In the LED having such a structure, almost the entire amount of light emitted from the light emitting element can be light-controlled by the reflecting mirror, so that high external radiation efficiency can be realized.

[0003]

However, in the LED having such a structure, a part of the light reflected by the reflecting mirror is blocked by the light emitting element or the lead and is not radiated to the outside. Therefore, when the size of the LED is reduced, the size of the light emitting element or the lead does not change, so that the ratio of the light shielding area to the radiation area is greatly increased, and there is a problem that the external radiation efficiency is greatly reduced. To address this problem, a patent application for a reflective LED 101 as shown in FIG. 8 has been filed (JP-A-6-350140). This reflective LED 10
1 is that the reflecting surface of the reflecting mirror 105 other than below the light emitting element 102 is a paraboloid of revolution with the light emitting element 102 as the focal point, and only the lower part of the light emitting element 102 is a convex conical shape 105a.
Light emitted directly below the light emitting element 102 is also to be externally emitted.

However, in the reflecting mirror 105 having such a shape,
Since the discontinuous sharp edge portion 105b is generated, the light distribution characteristic of the reflected light is discontinuous, and continuous smooth emitted light cannot be obtained. Further, when the shape of the reflecting mirror 105 is formed by a resin mold, voids are easily generated,
When a metal plate is pressed to be formed, it has an extremely inflection point, so that it is difficult to obtain a good product and the surface roughness becomes poor.

Accordingly, the present invention provides a practical reflection type LED which can maintain a high level of external radiation efficiency even if it is miniaturized, and can obtain a radiation light having a smooth and continuous light distribution.
It is an object to provide

[0006]

According to a first aspect of the present invention, there is provided a reflection type light emitting diode provided with a light emitting element, a lead for supplying power to the light emitting element, and a light emitting surface of the light emitting element. A reflecting mirror consisting of a smooth substantially continuous surface except for a central point that emits light emitted from the light emitting element in a direction that does not reach the periphery of the light emitting element and then externally emits, and a radiating portion on the back side of the light emitting element. It is provided. Here, the radiating portion may be a radiating surface which is an interface of the light transmitting material, or may be a hollow open portion having nothing.

[0007] "Smooth substantially continuous surface except for the center point"
Means a part of a polygon (straight lines 65a, 65b, 65c, 65d, 65e, 65f, 6f) as shown in FIG.
5g, 65h. ) Is rotated about the central axis, or a part of an ellipse whose focal point is the light emitting element 72 and a point outside the resin 76 as shown in FIG. 7B is rotated about the central axis. It is a combination of the center axis symmetric shape 75a and the paraboloid of revolution 75b having the light emitting element 72 as a focal point. Although these are discontinuous surfaces in a strict sense, they are surfaces that can be regarded as smooth and substantially continuous except for a convex portion at the center point without a sudden change in surface shape that causes a sharp edge.

Therefore, even if the size of the reflection type LED is reduced and the area ratio of the light emitting element in the light shielding part (light emitting element and lead part) to the area of the radiating part is increased, the light reflected by the reflecting mirror does not surround the light emitting element. Therefore, light is not emitted by the light-emitting element because the light is emitted outside the LED, and the reflection-type LED can maintain a high external radiation efficiency even if it is miniaturized.
In addition, the mirror provides smooth and continuous light distribution, and has excellent surface roughness with high accuracy, both when the reflector is formed by resin molding and by pressing a metal plate. And a practical reflection type LED provided with

According to a second aspect of the present invention, in the reflective light emitting diode according to the first aspect, the light emitting element and a part of the lead portion are sealed, and a space between the light emitting element and the reflecting mirror is filled. Having a light transmitting material. Therefore, there is no need to worry about deterioration due to humidity by sealing the light emitting element. In addition, since a part of the lead portion is sealed, the wire bonding is protected from the outside, and a reliable electrical connection can be obtained. further,
By filling the space between the light emitting element and the reflecting mirror with the light transmitting material, the refractive index becomes higher than in the case of a hollow body, and the light radiation efficiency is improved. As described above, the reflection type LED in which the reliability of the light emitting element and the wire bonding is improved and the external radiation efficiency is higher is obtained.

According to a third aspect of the present invention, in the reflective light emitting diode according to the first or second aspect, the reflecting mirror condenses the light of the light emitting element in a ring shape on a plane including the lead portion. Things. Here, as a method of converging the light in an annular shape, the shape of the reflecting mirror may be, for example, a light emitting element and a part of an ellipse having another point as two focal points may be a reflection type LE.
There is a method of forming a center-symmetric shape rotated around the central axis of D. As described above, by condensing the reflected light in a ring shape on the plane including the lead portion, the light can be collected around the light-emitting element while avoiding the light-emitting element. Therefore, the light is blocked only at two places of the lead portion, and almost all other light is radiated from the radiating portion, so that a high external radiation efficiency can be obtained.

According to a fourth aspect of the present invention, in the reflective light emitting diode according to the first or second aspect, the reflecting mirror condenses the light of the light emitting element at multiple points on a plane including the lead portion. Is what you do. Here, as a method of condensing light at multiple points, the shape of the reflecting mirror may be, for example, a shape obtained by collecting a plurality of spheroidal surfaces obtained by rotating an ellipse whose two focal points are a light emitting element and another point. There is a way to do that. As described above, by condensing the reflected light at multiple points on the plane including the lead portion, it is possible to collect the light while avoiding not only the light emitting element but also the lead portion. Therefore, almost the entire amount of light emitted from the light emitting element can be externally radiated, and higher external radiation efficiency can be obtained.

According to a fifth aspect of the present invention, in the reflective light emitting diode according to any one of the first to fourth aspects, the reflecting mirror has a diameter of 5 mm or less. Generally, the size of the light emitting element is 0.3 mm × 0.2 mm.
It is about 3 mm, and the size of the tip of the lead for mounting it is about 0.5 mm × 0.5 mm. Therefore, a reflective LED in which the diameter of the reflector exceeds 5 mm
In this case, since there is almost no influence of light shielding by the light emitting element, it is not necessary to devise the present invention. Conversely, when the diameter of the reflecting mirror becomes about 5 mm or less, the influence of light shielding of the light emitting element starts to appear, which is a problem of downsizing the reflective LED. Therefore, in the case of a reflective LED having a reflector diameter of 5 mm or less, it is necessary to avoid the influence of light shielding of the light emitting element by reflecting light emitted from the light emitting element in a direction not reaching the light emitting element and then radiating the light to the outside. is there. In this way, high external radiation efficiency can be maintained even in a small reflective LED in which the diameter of the reflector is 5 mm or less and the light-emitting element is affected by shading.

According to a sixth aspect of the present invention, there is provided the reflective light emitting diode according to any one of the first to fourth aspects, wherein the phosphor emits fluorescence around the light emitting element by receiving light from the light emitting element. It is provided with. In order to dispose the phosphor around the light emitting element, there is a method of mounting the light emitting element around the center with the tip of one lead in a cup shape and filling the surrounding cup with the phosphor. With such a structure, even if the reflection type LED itself is not miniaturized,
The cup filled with the phosphor increases the area ratio of the light-shielding portion. However, according to the reflective LED of the present invention, the light reflected by the reflecting mirror does not reach the periphery of the light emitting element and is emitted from the radiating portion to the outside, so that light is not blocked by the cup filling the phosphor, The reflection type LED can maintain high external radiation efficiency even with the phosphor.

According to a seventh aspect of the present invention, in the reflective light emitting diode according to any one of the first to fourth aspects, the plurality of light emitting elements are provided. In order to mount a plurality of light emitting elements, there is a method of mounting the plurality of light emitting elements on the bottom by forming the tip of one of the leads into a cup shape and filling the surrounding cup with a diffusing material. With such a structure, the area ratio of the light-shielding portion is increased by the cup for mounting a plurality of light-emitting elements without reducing the size of the reflective LED itself. However, according to the reflection type LED of the present invention, the light reflected by the reflector is not radiated to the periphery of the light emitting element but is radiated to the outside, so that light is not blocked by a cup mounting a plurality of light emitting elements. Even if the light emitting element is provided, the reflection type LED can keep the external radiation efficiency high.

According to an eighth aspect of the present invention, in the reflective light emitting diode according to any one of the second to seventh aspects, the reflecting mirror is molded with the light transmitting material and the surface is mirror-finished. It was done. Here, as a method of mirror finishing, there is a method of performing metal evaporation on the surface of the light-transmitting material. According to this method, mass production of the reflection type LED becomes possible, and cost reduction can be achieved.

According to a ninth aspect of the present invention, in the reflective light emitting diode according to any one of the first to seventh aspects, the reflecting mirror is a metal plate processed into a concave shape or a concave surface of the metal plate. Is plated. Therefore, it is resistant to temperature changes, and does not lose its function as a reflecting mirror due to the occurrence of wrinkles due to temperature changes, unlike a reflecting mirror metal-deposited on a resin surface. Can be handled. As a result, it can be used as a surface-mounted component without any limitation, so that it is suitable as a reflection-type LED to be mounted in a large amount. In particular, since there is a great demand for a miniaturized reflective LED as a surface mount component, it becomes a more practical reflective LED when miniaturized.

[0017]

Embodiments of the present invention will be described below.

FIG. 1A is a longitudinal sectional view showing the entire structure of the reflective light emitting diode according to the first embodiment of the present invention.
FIG. 2B is a plan view showing a state of light collection in the reflective light emitting diode according to the first exemplary embodiment of the present invention. FIG.
FIG. 3 is a longitudinal sectional view showing the entire configuration of the reflective light emitting diode according to the second embodiment of the present invention. FIG. 3 is a longitudinal sectional view illustrating the entire configuration of the reflective light emitting diode according to the third embodiment of the present invention. FIG. 4 shows Embodiment 4 of the present invention.
1 is a plan view showing the entire configuration of a reflection type light emitting diode according to FIG. FIG. 5 is a longitudinal sectional view illustrating the entire configuration of the reflective light emitting diode according to the fifth embodiment of the present invention. FIG.
FIG. 9 is a longitudinal sectional view showing an overall configuration of a reflective light emitting diode according to a sixth embodiment of the present invention.

Embodiment 1 As shown in FIG. 1, a reflective light-emitting diode 1 according to Embodiment 1 of the present invention includes a pair of leads 3a and 3b for supplying power to a light-emitting element 2.
The light emitting element 2 is mounted on one of the leads 3a, and the other lead 3b and the light emitting element 2 are bonded to each other with a wire 4 to make electrical connection.
The light emitting element 2 is formed by molding the shape of the reflection surface on the light emitting surface side and the shape (flat surface) of the radiation surface 7 on the back side. The reflecting mirror 5 is formed by depositing metal on the reflecting surface.

The shape of the reflecting surface is such that the position of the light emitting element 2 is the first position.
And the point f1 outside the transparent epoxy resin 6
A part of the ellipse which is the focal point is rotated about the central axis of the reflective LED 1 so as to have a central axis symmetrical shape. Therefore, it is a smooth substantially continuous surface except for the center point. In the reflective LED 1 having such a structure, light emitted from the light emitting element 2 and reflected by the reflecting mirror 5 passes through a point f1 about the central axis of the reflective LED 1 as shown in FIG. 1B. Light is collected toward the circle 8. Actually, the light condensed on the circle 8 is very small due to the refraction on the radiation surface 7, but almost all the light emitted from the light emitting element 2 passes near the circle 8. Become.

Therefore, the light emitted from the light emitting element 2 and reflected by the reflecting mirror 5 is reflected in a direction not reaching the periphery of the light emitting element 2, and the plane including the leads 3a and 3b does not include the periphery of the light emitting element 2. Since the light is condensed on the annular area and further radiated to the outside after being condensed, the reflection type LED 1 is downsized and the light-shielding portion (the light-emitting element 2 and the lead
Even if the area ratio of the light-emitting element 2 in (a, 3b) increases, no light-shielding by the light-emitting element 2 occurs. The light is shielded only at two points where the two leads 3a and 3b and the circle 8 intersect. As a result, a reflection-type LED that can maintain high external radiation efficiency even if it is miniaturized. Further, since the reflecting mirror 5 is a smooth and substantially continuous surface except for the center point, it is possible to obtain a radiated light having a smooth and continuous light distribution, and to accurately form the reflecting mirror 5 even when the reflecting mirror 5 is formed of a resin mold. Practical reflection type L equipped with reflection mirror 5 having excellent surface roughness
Can be ED.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 2, the reflection type light emitting diode 11 according to the second embodiment is configured such that, of a pair of leads 13a and 13b for supplying power to the light emitting element 12, the tip of one of the leads 13a is shaped like a cup 12a. Light emitting element 1 in the center
2 and mount the phosphor 1 in the cup 12a around it.
8 and a transparent epoxy resin mixture.

Then, the other lead 13b and the light emitting element 12 are bonded to each other with a wire 14 and the electrically connected lead is sealed with a transparent epoxy resin 16 and reflected on the light emitting surface side of the light emitting element 12. As for the shape of the surface, the shape (flat surface) of the radiation surface 17 is molded on the back side. Further, the reflecting mirror 15 is formed by performing metal deposition on the reflecting surface.

The shape of the reflecting surface is such that a portion of the ellipse having the position of the cup 12a on which the light emitting element 12 is mounted as the first focal point and the point f2 outside the transparent epoxy resin 16 as the second focal point is a reflection type. It is formed in a central axis symmetrical shape rotated around the central axis of the LED 11.

The light emitting element 12 is an ultraviolet light emitting element, and the phosphor 18 emits white fluorescent light upon receiving the radiation of the ultraviolet light. Therefore, the cup 12 of the reflective LED 11
White fluorescent light is emitted toward the reflecting mirror 15 from the lower surface of “a”.

In the reflective LED 11 having such a structure, the area ratio of the light-shielding portion is increased by the cup 12a filled with the phosphor 18 without reducing the size of the reflective LED 11 itself. However, the light emitted from the cup 12a and reflected by the reflecting mirror 15 is collected toward a circle passing through the point f2 around the central axis of the reflective LED 11. In practice, the light condensed on this circle is very small due to refraction at the radiation surface 17, but the cup 12a
Almost all light emitted from passes through the vicinity of this circle.

Accordingly, the light emitted from the cup 12a and reflected by the reflecting mirror 15 is reflected outside in a direction not reaching the periphery of the cup 12a and then radiated externally, so that the light is not blocked by the cup 12a. Even if the phosphor 18 is used, the reflection type LED can keep the external radiation efficiency high.

In the second embodiment, the light emitting element 12 is an ultraviolet light emitting element and the phosphor 18 emits white fluorescent light upon receiving ultraviolet rays. However, the combination of the light emitting element and the phosphor is not limited to this. It is not limited. For example, the light emitting element 12 is a blue light emitting element, and the phosphor 18
May receive blue light and emit yellow fluorescence.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG. As shown in FIG. 3, the reflective light emitting diode 21 according to the third embodiment includes three light emitting elements R, G, and B.
Of the leads 23a and 23b for supplying power to the red light emitting element R, the green light emitting element G, and the blue light emitting element B are mounted inside with the tip of one of the leads 23a being shaped like a cup 22, and around these light emitting elements. Material 2 in cup 22
8 and a transparent epoxy resin mixture. As the diffusing material 28, fine powder of silica is generally used.
It is used to diffuse and mix the light emitted by the light emitting elements R, G, B of the colors.

The other lead 23b is divided into three, and is electrically connected to the three light emitting elements R, G, B by three wires 24R, 24G, 24B, respectively. The lead portion is sealed with a transparent epoxy resin 26, and the shape of the reflecting surface is molded on the light emitting surface side of the light emitting elements R, G, B, and the shape (flat surface) of the radiation surface 27 is molded on the back side. Further, the reflecting mirror 25 is formed by performing metal deposition on the reflecting surface.

As described above, since the three light emitting elements R, G, and B are separately electrically connected, each of the light emitting elements R, G, and B is connected.
The power supplied to G and B can be freely controlled, whereby the brightness of each light emitting element R, G and B is variously controlled and mixed with the diffusion material 28 to emit light of various colors. be able to.

The shape of the reflection surface is an ellipse having the position of the cup 22 on which the light emitting elements R, G, and B are mounted as the first focal point and the point f3 outside the transparent epoxy resin 26 as the second focal point. It is formed in a central axis symmetrical shape in which the portion is rotated around the central axis of the reflective LED 21.

In the reflective LED 21 having such a structure, the area ratio of the light shielding portion is increased by the cup 22 filled with the diffusion material 28 without reducing the size of the reflective LED 21 itself. However, the light emitted from the cup 22 and reflected by the reflecting mirror 25 is collected toward a circle passing through the point f3 around the central axis of the reflective LED 21. Actually, the light condensed on this circle is very small due to the refraction at the radiation surface 27, but almost all the light emitted from the cup 22 passes near this circle.

Accordingly, the light emitted from the cup 22 and reflected by the reflector 25 is reflected in a direction that does not reach the periphery of the cup 22 and then radiated to the outside.
2 does not occur, and a plurality of light emitting elements R,
Even if G and B are used, the reflection type LED can maintain high external radiation efficiency.

In the third embodiment, the case where the light emitting elements R, G, and B of three primary colors of light are used as the plurality of light emitting elements has been described. However, a combination of two colors and other light emitting elements such as yellow and purple are used. Various combinations such as a combination with a color light emitting element are possible. In some cases, two or more light emitting elements of the same color may be used side by side.

Fourth Embodiment Next, a fourth embodiment of the present invention will be described with reference to FIG. The reflection type LED 31 of the fourth embodiment differs from the first to third embodiments in the shape of the reflecting mirror 35.

As shown in FIG. 4, the reflection type LED 31 of the fourth embodiment supplies the power to the light emitting element 32.
One lead 33a of the pair of leads 33a and 33b
The light emitting element 32 is mounted on the
The lead portion, which has been electrically connected by bonding the light emitting element 32 and the light emitting element 32 with each other, is sealed with a transparent epoxy resin. Is molded. Then, the reflecting mirror 35 is formed by performing metal evaporation on the reflecting surface.
Are formed.

The shape of the reflecting mirror 35 is such that the position of the light emitting element 32 is the first focal point, and the point f4 inside the transparent epoxy resin 6 is
a, f4b, f4c, f4d, f4e, and portions 35a, 3 of six spheroids each having f4f as a second focal point.
5b, 35c, 35d, 35e, and 35f are formed in a connected shape. Reflective LED 3 having such a structure
In 1, in the light emitted from the light emitting element 32, the light reflected by the reflection surface 35a is collected at the point f4a. Similarly, the light reflected by the reflecting surface 35b is at a point f4b, the light reflected by the reflecting surface 35c is at a point f4c, the light reflected by the reflecting surface 35d is at a point f4d, and the light reflected by the reflecting surface 35e. Represents the point f4e, and the light reflected by the reflection surface 35f represents the point f4.
f.

As described above, the light emitted from the light emitting element 32 is all six points f4a, f4b, f4c, f4d, f
Light is condensed separately into 4e and f4f. Therefore, not only the periphery of the light emitting element 32 but also the two leads 33a, 33
Since the light is reflected and condensed while avoiding the vicinity of b, almost the entire amount of light emitted from the light emitting element 32 is radiated from the radiation surface to the outside without any light shielding. This makes it possible to maintain a high external radiation efficiency even if the size is reduced.
Becomes

Fifth Embodiment Next, a fifth embodiment of the present invention will be described with reference to FIG. Embodiment 5 is different from Embodiments 1 to 4 in that the reflecting mirror is formed by pressing a metal plate.

As shown in FIG. 5, the reflection type LED 41 according to the fifth embodiment supplies a power to the light emitting element 42.
One lead 43a of the pair of leads 43a and 43b
The light emitting element 42 is mounted on the other lead 43b.
A reflecting mirror 45 formed by pressing a copper alloy plate to form a concave shape and then performing silver plating on the concave surface is attached to a lead portion where the light emitting element 42 and the light emitting element 42 are bonded by a wire 44. The shape (flat surface) of the radiation surface 47 is molded on the back side of the light emitting element 42 while sealing with 46.

As in the first to third embodiments, the shape of the reflecting surface of the reflecting mirror 45 is such that the position of the light emitting element 42 is the first focal point and the point f5 outside the transparent epoxy resin 46 is the second focal point. A part of the ellipse is rotated about the central axis of the reflective LED 41 and is formed in a central axis symmetrical shape. Therefore, it is a smooth substantially continuous surface except for the center point. In the reflection type LED 41 having such a structure, the light emitted from the light emitting element 42 and reflected by the reflection mirror 45 is collected toward a circle passing through the point f5 with the center axis of the reflection type LED 41 as the center. Actually, since there is refraction on the radiation surface 47, the light condensed on this circle is very small.
Almost all light emitted from 2 will pass near this circle.

Therefore, the light emitted from the light emitting element 42 and reflected by the reflecting mirror 45 is reflected in a direction not reaching the periphery of the light emitting element 42 and then radiated outside, so that the size of the reflective LED 41 is reduced. Even if the area ratio of the light-emitting element 42 in the light-shielding portion (light-emitting element 42 and lead portions 43a and 43b) with respect to the radiation surface 47 increases, light-shielding by the light-emitting element 42 does not occur. As a result, a reflection-type LED that can maintain high external radiation efficiency even if it is miniaturized. Further, a radiation light having a smooth and continuous light distribution can be obtained, and even when the reflecting mirror 45 is formed by pressing a metal plate, the reflecting mirror 45 is provided with the reflecting mirror 45 having excellent surface roughness with high accuracy. Reflective LED.

Further, the reflecting mirror 45 is obtained by subjecting a concave surface of a copper alloy plate processed into a concave shape to silver plating.
Therefore, it is resistant to temperature changes, and does not lose its function as a reflecting mirror due to the occurrence of wrinkles due to temperature changes, unlike a reflecting mirror metal-deposited on a resin surface. Can be handled. As a result, it can be used as a surface-mounted component without any limitation, so that it is suitable as a reflection-type LED to be mounted in a large amount. In particular, there is a great demand for miniaturized reflective LEDs as surface mount components,
When the size is reduced, the reflective LED becomes more practical.

Sixth Embodiment Next, a sixth embodiment of the present invention will be described with reference to FIG. The sixth embodiment differs from the first to fifth embodiments in that a base for supporting the lead portion is formed by resin molding, and a reflecting mirror is formed on the bottom surface of the base.

As shown in FIG. 6, in the reflective LED 51 of the sixth embodiment, the same shape as in the first to third and fifth embodiments is provided on the bottom surface of the base 56 formed by injection molding acrylic resin. Is molded, and the reflecting mirror 55 is formed by metal vapor deposition on the reflecting surface. Two leads 53a and 53b are penetrated and mounted on the upper portion of the base 56, and the light emitting element 52 is mounted on the lead 53a.
4 is bonded. In addition, the light emitting element 52
It is adjusted so that a part of the ellipse constituting the reflection surface is located at one of the focal points of the ellipse on the surface rotated around the central axis.

In the reflection type LED 51 having such a structure, the light emitted from the light emitting element 52 and reflected by the reflection mirror 55 is directed to a circle centered on the central axis of the reflection type LED 51 and passing through another focal point f6 of the ellipse. Is collected. Therefore, the light emitted from the light emitting element 52 and reflected by the reflecting mirror 55 is reflected in a direction not reaching the periphery of the light emitting element 52 and is then radiated to the outside. Therefore, the size of the reflective LED 51 is reduced and the light shielding portion ( Light emitting element 52 and leads 53a, 5
In 3b), even if the area ratio of the light emitting element 52 is increased, light is not blocked by the light emitting element 52. As a result, a reflection-type LED that can maintain high external radiation efficiency even if it is miniaturized.

The reflection type LED 51 according to the sixth embodiment
In the above, a base 56 formed by injection molding an acrylic resin
Since the reflecting mirror 55 is formed by metal vapor deposition, mass production is possible, and the cost of the reflective LED 51 can be reduced. In the sixth embodiment, the base 56 is formed of an acrylic resin, but other resins such as a polycarbonate resin may be used.

The reflection type LED 51 according to the sixth embodiment
Has no radiating surface, the radiating portion is a hollow open portion, and the light emitting element 52 is exposed to outside air. What is necessary is just to cover the upper surface of 56 with a glass plate, and to shield the inside with dry nitrogen.

[0050]

As described above, the reflection type light emitting diode according to the first aspect of the present invention has a light emitting element, a lead for supplying power to the light emitting element, and a light emitting surface of the light emitting element. A reflecting mirror for reflecting light emitted from the light emitting element in a direction not reaching the periphery of the light emitting element and then radiating the light to the outside; and a radiating portion on the back side of the light emitting element. Therefore, the size of the reflection type LED is reduced, and the light-shielding portion (light-emitting element and lead portion) with respect to the area of the radiating portion is reduced.
Even if the area ratio of the light-emitting element increases, the light reflected by the reflecting mirror is emitted outside without reaching the periphery of the light-emitting element. The reflection type LED can keep the efficiency high. In addition, a radiation mirror with smooth and continuous light distribution can be obtained, and a reflection mirror with excellent surface roughness can be obtained with high accuracy regardless of whether the reflection mirror is formed by a resin mold or a metal plate press. It can be provided with a practical reflection type LED provided.

According to a second aspect of the present invention, in the reflective light emitting diode according to the first aspect, the light emitting element and a part of the lead portion are sealed, and a space between the light emitting element and the reflecting mirror is filled. Having a light transmitting material. Therefore, in addition to the effect of the first aspect, since the light emitting element is sealed, there is no fear of deterioration due to humidity. In addition, since a part of the lead portion is sealed, the wire bonding is protected from the outside, and a reliable electrical connection can be obtained. Further, by filling the space between the light emitting element and the reflecting mirror with the light transmitting material, the refractive index becomes higher than in the case of a hollow body, and the light radiation efficiency is improved.
As described above, the reliability of the light emitting element and the wire bonding is improved, and the external light emitting efficiency is further improved.
ED.

According to a third aspect of the present invention, in the reflective light emitting diode according to the first or second aspect, the reflecting mirror condenses the light of the light emitting element in a ring shape on a plane including the lead portion. Things. As described above, by converging the reflected light in a ring shape on the plane including the lead portion, in addition to the effect described in claim 1 or 2, light can be collected around the light emitting element while avoiding the light emitting element. . Therefore, the light is blocked only at two places of the lead portion, and almost all other light is radiated from the radiating portion, so that a high external radiation efficiency can be obtained.

According to a fourth aspect of the present invention, in the reflective light emitting diode according to the first or second aspect, the reflecting mirror condenses the light of the light emitting element at multiple points on a plane including the lead portion. Is what you do. In this way, by condensing the reflected light at multiple points on the plane including the lead portion, in addition to the effects described in claim 1 or 2, the light is avoided not only at the light emitting element but also at the lead portion. Can be collected. Therefore, almost the entire amount of light emitted from the light emitting element can be externally radiated, and higher external radiation efficiency can be obtained.

According to a fifth aspect of the present invention, in the reflective light emitting diode according to any one of the first to fourth aspects, the reflecting mirror has a diameter of 5 mm or less. Generally, the size of the light emitting element is 0.3 mm × 0.2 mm.
It is about 3 mm, and the size of the tip of the lead for mounting it is about 0.5 mm × 0.5 mm. Therefore, a reflective LED in which the diameter of the reflector exceeds 5 mm
In this case, since there is almost no influence of light shielding by the light emitting element, it is not necessary to devise the present invention. Conversely, when the diameter of the reflecting mirror becomes about 5 mm or less, the influence of light shielding of the light emitting element starts to appear, which is a problem of downsizing the reflective LED. Therefore, in the case of a reflective LED having a reflector diameter of 5 mm or less, it is necessary to avoid the influence of light shielding of the light emitting element by reflecting light emitted from the light emitting element in a direction not reaching the light emitting element and then radiating the light to the outside. is there. In this way, in addition to the effect according to any one of claims 1 to 4, a small reflective LED in which the diameter of the reflecting mirror is 5 mm or less and the effect of shading by the light emitting element is exerted. In this case, high external radiation efficiency can be maintained.

According to a sixth aspect of the present invention, in the reflective light emitting diode according to any one of the first to fourth aspects, the phosphor emits fluorescence around the light emitting element by receiving light from the light emitting element. It is provided with. In order to dispose the phosphor around the light emitting element, there is a method of mounting the light emitting element around the center with the tip of one lead in a cup shape and filling the surrounding cup with the phosphor. With such a structure, even if the reflection type LED itself is not miniaturized,
The cup filled with the phosphor increases the area ratio of the light-shielding portion. However, according to the reflective LED of the present invention, the light reflected by the reflecting mirror is radiated outside from the radiating portion without reaching the periphery of the light emitting element.
In addition to the effect described in any one of the above, in addition to the fact that light is not blocked by the cup filled with the phosphor, the reflection type LED can maintain high external radiation efficiency.

According to a seventh aspect of the present invention, in the reflective light emitting diode according to any one of the first to fourth aspects, the plurality of light emitting elements are provided. In order to mount a plurality of light emitting elements, there is a method of mounting the plurality of light emitting elements on the bottom by forming the tip of one of the leads into a cup shape and filling the surrounding cup with a diffusing material. With such a structure, the area ratio of the light-shielding portion is increased by the cup for mounting a plurality of light-emitting elements without reducing the size of the reflective LED itself. However, according to the reflection type LED of the present invention, the light reflected by the reflection mirror is radiated outside without reaching the periphery of the light emitting element.
In addition to the effects described in any one of the fourth to fourth aspects, there is no light blocking by a cup for mounting a plurality of light emitting elements, and the reflection type LED can maintain high external radiation efficiency.

According to an eighth aspect of the present invention, in the reflection type light emitting diode according to any one of the second to seventh aspects, the reflecting mirror is molded with the light transmitting material and the surface is mirror-finished. It was done. According to this method, in addition to the effects described in any one of claims 2 to 7, mass production of the reflective LED becomes possible, and cost reduction can be achieved.

According to a ninth aspect of the present invention, in the reflective light emitting diode according to any one of the first to seventh aspects, the reflecting mirror is a metal plate processed into a concave shape or a concave surface of the metal plate. Is plated. Therefore, in addition to the effects described in any one of claims 1 to 7, it has resistance to temperature changes,
Since the function as a reflecting mirror is not lost due to the occurrence of wrinkles due to a temperature change as in the case of a reflecting mirror in which metal is vapor-deposited on a resin surface, it is possible to support a reflow furnace for surface mounting. As a result, it can be used as a surface-mounted component without any limitation, so that it is suitable as a reflection-type LED to be mounted in a large amount. In particular, since there is a great demand for a miniaturized reflective LED as a surface mount component, it becomes a more practical reflective LED when miniaturized.

[Brief description of the drawings]

FIG. 1A is a longitudinal sectional view showing an entire configuration of a reflective light emitting diode according to a first embodiment of the present invention;
FIG. 2B is a plan view showing a state of light collection in the reflective light emitting diode according to the first exemplary embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view illustrating an entire configuration of a reflective light emitting diode according to a second embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view illustrating an entire configuration of a reflective light-emitting diode according to a third embodiment of the present invention.

FIG. 4 is a plan view showing an entire configuration of a reflective light-emitting diode according to a fourth embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing the entire configuration of a reflective light-emitting diode according to a fifth embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing the entire configuration of a reflective light-emitting diode according to a sixth embodiment of the present invention.

7A is a longitudinal sectional view showing an example of a reflecting mirror having a smooth substantially continuous surface except for a center point, and FIG. 7B is a longitudinal sectional view showing another example.

FIG. 8 is a longitudinal sectional view showing the entire configuration of a reflection type light emitting diode according to a conventional technique.

[Explanation of symbols]

1,11,21,31,41,51 Reflective light emitting diode 2,12, R, G, B, 32,42,52 Light emitting element 3a, 3b, 4,13a, 13b, 14 Lead part 5,15,25 , 35, 45, 55 Reflecting mirror 6, 16, 26, 46 Light transmitting material 7, 17, 27, 47 Radiating part 18 Phosphor

Claims (9)

[Claims] A light-emitting element; a lead section for supplying power to the light-emitting element; and a light-emitting element provided to face the light-emitting surface of the light-emitting element so that light emitted from the light-emitting element does not reach the periphery of the light-emitting element. A reflective light emitting diode comprising: a reflecting mirror having a smooth and substantially continuous surface except for a central point that emits external light after being reflected to the light emitting element; and a radiating portion on the back side of the light emitting element. 2. The light-emitting device according to claim 1, further comprising a light-transmissive material that seals a part of the light-emitting element and the lead portion and fills a space between the light-emitting element and the reflector. Reflective light emitting diode. 3. The reflection type light emitting diode according to claim 1, wherein the reflecting mirror condenses the light of the light emitting element in a ring shape on a plane including the lead portion. 4. The reflection type light emitting diode according to claim 1, wherein the reflection mirror condenses the light of the light emitting element at multiple points on a plane including the lead portion. 5. The reflection mirror according to claim 1, wherein the reflection mirror has a diameter of 5 mm or less.
4. The reflective light-emitting diode according to any one of the above. 6. The light emitting device according to claim 1, wherein the light emitting device includes a phosphor around the light emitting device to emit fluorescence by receiving light from the light emitting device. Reflective light emitting diode. 7. The reflection type light emitting diode according to claim 1, wherein the light emitting element is plural. 8. The reflection according to claim 2, wherein the reflection mirror is molded with the light transmitting material, and has a surface mirror-finished. Type light emitting diode. 9. The reflection mirror according to claim 1, wherein the reflection mirror is a metal plate processed into a concave shape, or the concave surface of the metal plate is plated. 3. The reflective light emitting diode according to item 1.