JP2000315824A - Light emitting diode and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a light emitting diode emitting light with high visibility and high wavelength conversion efficiency by providing a light emitting element mounted in the center on the head part of a pin, and a resin being mixed selectively with a material for converting the wavelength of emitted light provided in the vicinity of the light emitting element. SOLUTION: The light emitting diode (LED) comprises a light emitting element 2 mounted on a planar pin 5 or a substrate 3 while being secured and protected with a resin 8 mixed with a fluorescent material 9. With such an arrangement, light emitted from the light emitting element 2 can be subjected to efficient wavelength conversion and outputted as a light irradiating over a wide range visually confirmable from a hemispherical plane of about 180 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a light emitting diode and a method for manufacturing the same, and more particularly, to a light emitting diode having high visibility of emitted light and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, light emitting diodes (light e
(mitting diode, hereinafter abbreviated as LED)
In addition to infrared, red, yellow, and green colors, blue light-emitting elements have been put to practical use, and high-luminance light-emitting elements have also been put into practical use. It has become.

FIG. 13 is a diagram showing a schematic configuration of a conventional LED, wherein FIG. 13A is a top view thereof, and FIG. 13B is a sectional view thereof. As shown in FIG.
Reference numeral 101 denotes a light emitting element 102 disposed in a cup 105 formed on a lead pin 104-2, and lead pins 104-1 and 104-1 respectively connected by wires 106-1 and 106-2.
04-2, and lead pins 104-1 and 104-
The light emitting element 102 is configured as a part of a circuit with 2 as a terminal. Each of these parts is protected by a bullet-shaped transparent resin 107.

FIG. 14 is an enlarged view of a portion b surrounded by a broken line in FIG. As shown in FIG.
The cup 105 has a mortar-like shape in which the height from the edge to the bottom where the light emitting element is arranged is increased, and the light emitting element 102 is arranged inside the cup. In the cup 105, a resin 10 (the material may be the same) different from the resin 107 is used.
8 is filled.

As shown in FIG. 14B, some LEDs have a resin 108 filling a cup 105 mixed with a fluorescent substance 109, and these resins 108 are substantially parallel to an edge of the upper surface of the cup 105. Is filled. The fluorescent substance 109 is excited when, for example, blue light is emitted from the light emitting element 102, and emits light having a wavelength different from that of the blue light. Therefore, an LED that emits white light can be formed by mixing the fluorescent substance 109 with the resin 108 (JP-A-5-152609, JP-A-7-99).
345, JP-A-10-65221).

As described above, when the light emitting element 102 is arranged in the cup 105 having a high top edge so as to completely cover the light emitting element 102, light emitted from the light emitting element 102 Light-emitting element 10 reflected on a wall
13B, and are collected and output in one direction by the action of the resin 107 as indicated by the arrow in FIG.

[0007]

SUMMARY OF THE INVENTION As described above, an LED that outputs light concentrated in one direction by reflection in a cup
Has a high luminance, and a mixture of a fluorescent substance has an advantage that a light-emitting element and a fluorescent substance are formed in a cup so that color mixing by light of different wavelengths outside does not occur.

However, light having high directivity, which is collected and output in one direction, does not cause color mixing with light having a different wavelength outside from the structure thereof. The light cannot be recognized from an angle, and the light cannot be recognized at all from an angle different from the output light by 90 degrees or more. Therefore, the use of the LED has been limited.

When a fluorescent substance is mixed with a resin, the amount of the fluorescent substance necessary for wavelength conversion may be sufficient to cover the light emitting element, and the mixing of an excessive amount of the fluorescent substance lowers the efficiency of the wavelength conversion. Also.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light emitting diode which outputs light with good visibility and has high wavelength conversion efficiency, and a method for manufacturing the same.

[0011]

According to a first aspect of the present invention, there is provided a pin having a flat portion and a light emitting element mounted at the center of the pin. And a first resin that covers the light emitting element and selectively mixes at least a portion close to the light emitting element with a wavelength conversion substance that converts the wavelength of light emitted from the light emitting element. And

According to a second aspect of the present invention, in the first aspect of the present invention, the wavelength conversion substance is a fluorescent substance.

According to a third aspect of the present invention, in the first aspect of the present invention, the first resin has a hemispherical shape having a diameter equal to or smaller than the head of the pin.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the head of the pin has a dish shape having a flat portion at the center. Note that the pin head may be configured to have a shallow dish shape having a flat portion at the center.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the head of the pin has a bank-shaped surrounding portion on a circumference of an edge thereof.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the surrounding portion is formed of a second resin different from the first resin.

Further, in the invention according to claim 7, the substrate, the light emitting element mounted on the substrate, and a wavelength conversion material which covers the light emitting element and converts a wavelength of light emitted from the light emitting element are provided. A first resin which is selectively mixed at least in a portion adjacent to the light emitting element.

According to an eighth aspect of the present invention, in the seventh aspect of the present invention, the wavelength conversion substance is a fluorescent substance.

According to a ninth aspect of the present invention, in the seventh aspect of the present invention, the first resin has a hemispherical shape protruding from a mounting position of the light emitting element.

According to a tenth aspect of the present invention, in the seventh aspect of the present invention, the substrate has a groove around a mounting position of the light emitting element.

According to an eleventh aspect of the present invention, in the seventh aspect of the present invention, the mounting position of the light emitting element is a protrusion on the substrate.

In the twelfth aspect of the present invention, the step of mounting the light emitting element on the pin head or the substrate on which the flat portion is formed, and converting the wavelength of the light emitted from the light emitting element to the light emitting element. A step of dropping a liquid thermosetting resin in which the wavelength conversion substance is mixed, and a step of moving the wavelength conversion substance to the vicinity of the light emitting element within the thermosetting resin,
Heating and curing the hemisphere.

[0023] According to the invention of claim 13, according to claim 12,
In the invention, the step of moving the wavelength conversion substance to the vicinity of the light emitting element in the thermosetting resin is performed by precipitating the wavelength conversion substance in the thermosetting resin.

[0024] According to the fourteenth aspect of the present invention, the twelfth aspect is provided.
Alternatively, in the invention according to the thirteenth aspect, the wavelength conversion substance is a fluorescent substance.

According to the fifteenth aspect, in the twelfth aspect,
In the invention, the step of moving the wavelength conversion substance to the vicinity of the light emitting element in the thermosetting resin includes moving the wavelength conversion substance to the vicinity of the light emitting element in the thermosetting resin and the heat It is characterized in that the curable resin is formed into a hemisphere by utilizing its surface tension.

In the invention according to claim 16, a step of mounting a light emitting element on a pin head or a substrate on which a flat portion is formed, and converting the wavelength of light emitted from the light emitting element to the light emitting element. The wavelength conversion substance is mixed, the viscosity is reduced by heating, a step of applying a resin that is cured by heating, and heating the resin to reduce the viscosity, the resin in the reduced viscosity resin The method is characterized by comprising at least a step of moving the wavelength conversion substance to the vicinity of the light emitting element and a step of further heating and curing the resin.

[0027] According to the invention of claim 17, there is provided claim 16.
In the invention of the above, the viscosity is reduced by heating the resin,
The step of moving the wavelength converting substance to the vicinity of the light emitting element in the resin having reduced viscosity is performed by causing the wavelength converting substance to precipitate in the resin.

According to the eighteenth aspect of the present invention,
Alternatively, in the invention according to the seventeenth aspect, the wavelength conversion substance is a fluorescent substance.

According to the nineteenth aspect, the sixteenth aspect provides
In the invention of the above, the viscosity is reduced by heating the resin,
The step of moving the wavelength converting substance to the vicinity of the light emitting element in the resin having reduced viscosity reduces the viscosity by heating the resin, and the light emitting the wavelength converting substance in the resin having reduced viscosity. The method is characterized in that the resin whose viscosity has been reduced is formed into a hemisphere by utilizing its surface tension while being moved to the vicinity of the element.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a light emitting diode according to the present invention and a method for manufacturing the same will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing a schematic configuration of a light emitting diode according to the present invention, and FIG.
FIG. 2B shows the cross section. FIG. 2 is an enlarged view of a portion a surrounded by a broken line shown in FIG.

A light emitting diode (hereinafter abbreviated as LED) 1 includes a light emitting element 2 and a substrate 3 made of an insulator such as ceramic, lead pins 4-1 and 4-2, pins 5, wires 6-1 and 6-2. , Resin 7, resin 8, fluorescent substance 9
Consists of The light emitting element 2 is disposed on the pin 5 and fixed and protected by the resin 8, and the wire 6-1.
And 6-2 are electrically connected to lead pins 4-1 and 4-2. The pin 5 on which the light emitting element 2 is mounted and the lead pins 4-1 and 4-2 are arranged on the substrate 3 and are entirely protected by the resin 7. In such a configuration, when a predetermined voltage is applied between the lead pins 4-1 and 4-2, a current flows through the light emitting element 2 and light is emitted from the light emitting element 2. The light emitted from the light emitting element 2 is
, And light of another wavelength is emitted from the fluorescent substance 9 and output as, for example, white light. Since the light emitted from the light emitting element 2 does not block or reflect the light by the cup as in the conventional light emitting device, the surface of the resin 7 has all the hemispherical angles as shown by the arrow shown in FIG. 3 except for the surface in contact with 3). The fluorescent substance 9
Uses, for example, (Y, Gd, Ce) ₃ Al ₅ O ₁₂ .

Here, the resin 8 and the fluorescent substance 9 will be described. The resin 8 is a thermosetting resin having a property of being cured from a liquid state to a solid by heating, or a thermosetting resin having a property of being reduced in viscosity by heating and then being cured by further heating. .

In the case where the resin 8 is a thermosetting resin whose viscosity is reduced by heating, its characteristic is that if the resin 8 is heated at a constant temperature as shown in FIG. Thereafter, curing is gradually started, and after time A (for example, about 20 hours), it is almost completely cured. When this resin 8 is applied to the light emitting element 2 as shown in FIG. 4A and heated, the viscosity of the resin 8 decreases as shown in FIG. It becomes hemispheric on the pin 5 as shown. Thereafter, the resin 8 cures and becomes solid.

When the resin 8 is a thermosetting resin, as shown in FIG. 5A, the light emitting element 2 is mounted on the pins 5 and the liquid resin 8 is dropped from the nozzle 100. . Since the resin 8 dropped on the pin 5 is in a liquid state, it becomes hemispherical on the pin 5 as shown in FIG. Thereafter, when the resin 8 is heated for a certain period of time, the resin 8 hardens and becomes solid.

The resin 8 hardens and becomes solid, but the fluorescent substance 9 precipitates in this heating step.

FIG. 6 is a diagram schematically showing the manner in which the fluorescent substance 9 precipitates. As shown in FIG. 2A, the fluorescent substance 9 is almost uniformly mixed with the resin 8 immediately after the resin 8 is dropped. Thereafter, when the viscosity of the resin 8 is reduced by heating, as shown in FIG.
Precipitates in the resin 8 and covers the light emitting element 2 as shown in FIG. Thereafter, when further heated, the resin 8 is cured.

By the way, the amount of the fluorescent substance 9 may be sufficient to cover the light emitting element 2, and the substance precipitated on the pin 5 remote from the light emitting element 2 is meaningless because it does not absorb the light emitted from the light emitting element 2. Will be. Therefore, the resin 8 may be applied (dropped) near the light emitting element 2.

FIGS. 7 to 9 show examples of pin shapes suitable for dropping resin. The pin 15 shown in FIG. 7 has its head inclined in a shallow dish shape. This pin 15
When the light emitting element 12 is placed at the center of the substrate and the resin 18 is dropped, the influence of the surface tension becomes more remarkable due to the inclination of the pin 15, the resin 18 is uniformly applied around the light emitting element 12, and the fluorescent substance 9 emits light. It will precipitate near the element 12.

The pin 25 shown in FIG. 8 is formed by applying a resin 20 (the material may be the same as that of the resin 28) different from the resin 28 previously dropped on the head thereof in a circumferential shape.
When the light emitting element 22 is placed on the light emitting element 22 and the resin 28 is dropped, the resin 28 does not spread except for the portion surrounded by the resin 20, and the light emitting substance 29 precipitates only in the vicinity of the light emitting element 22.

The pin 35 shown in FIG. 9 has a circumferential enclosure 35a with the head portion embankment-shaped. Also in this case, similarly to the pin 25 shown in FIG. 8, the resin 38 is applied to the vicinity of the light emitting element 32 by placing the light emitting element 32 on the portion surrounded by the surrounding 35a and dropping the resin 38. The light emitting substance 39 precipitates near the light emitting element 32.

In any of the examples shown in FIGS. 7 to 9, the dish-shaped inclination and surroundings are at a height which does not affect the optical path of the light emitted from the light emitting element (the light whose wavelength is converted by the fluorescent substance 9). In addition, unlike the conventional cup shape, the light converted by the fluorescent substance 9 can be visually recognized from the side.

By using each of the methods shown in FIGS. 7 to 9, even if the area of the pin head is larger than the area where the resin is to be applied, the resin can be applied to a desired range.

FIG. 10 is a diagram showing an example of the configuration of an LED having a pin head larger than the resin application area.
Is a top view thereof, and FIG. 2B is a sectional view thereof.

As shown in the figure, the LED 41 includes lead pins 44-1 and 44 for supplying electricity to the light emitting element 42.
-2 are provided, and the light emitting element 42 and the wire 46-
1 and 46-2.

The light emitting element 42 includes a lead pin 44-
2 and the resin 48 is applied. Although the area of the head of the lead pin 44-2 is larger than the area to which the resin 48 is applied, the head of the lead pin 44-2 has the above-mentioned dish-shaped or encircled form or another resin. , The resin 48 is applied in a desired size.

In the above description, the case where the light emitting element is mounted on the pins or the lead pins has been described. However, the light emitting element can be mounted directly on the substrate or the like. In this case, it is also possible to form a bank-like surrounding portion by applying the above-mentioned another resin to a desired area on the substrate on which the light emitting element is mounted, thereby defining the resin application area, as shown in FIG. By using the substrate, the application range of the resin can be limited as in the case described with reference to FIGS.

FIG. 11 is a view showing an example of a substrate on which a light emitting element is directly mounted. The substrate 53 shown in FIG.
A columnar projection 53a is formed, and the projection 53a
A light emitting element 52 is placed at the center of the substrate and a resin 58 mixed with a fluorescent substance 59 is applied (dropped).

Further, a circumferential groove 63a is formed in the substrate 63 shown in FIG. 5B, and the light emitting element 62 is placed at the center of the region surrounded by the groove 63a and the fluorescent substance 69 is placed. Is applied (dropped).

When the light-emitting elements are directly mounted on the substrate, a plurality of light-emitting elements can be mounted close to each other, and a resin can be applied to the plurality of light-emitting elements collectively. FIGS. 12A and 12B are diagrams showing a configuration example of an LED in which a plurality of light emitting elements are mounted on a substrate, wherein FIG. 12A shows the upper surface and FIG. 12B shows the cross section.

As shown in the figure, an LED 71 is composed of a plurality of light emitting elements 72-1 to 72-3 on a substrate 73 having a projection.
Are mounted, and the light emitting elements 72-1 to 72-3 are connected to the lead pins 74-1 and 74-2 by wires, and the resin 78 is applied.

In the example shown in FIG. 12, the resin 78 is also applied to the lead pins 74-1 and 74-2, but the resin 7 is applied only to the light emitting elements 72-1 to 72-3.
It is clear from the above-mentioned embodiment that the coating 8 can be applied.

In this embodiment, the case where white light is output by mixing a fluorescent substance with a resin has been described. However, the substance mixed with the resin is not limited to the fluorescent substance, and may convert wavelengths or absorb specific wavelengths. The same applies to the case of a substance.

In this embodiment, the description has been given of the case where the fluorescent substance is precipitated in the resin. However, in addition to the above, when the resin is in a liquid or low viscosity state, the charged fluorescent substance is moved by an electric field. The fluorescent substance can be moved by another method, and the fluorescent substance can be prevented from being precipitated by the mixed fluorescent substance.

[0055]

As described above, according to the present invention, a light emitting device is mounted on a flat pin or a substrate,
Since the mounted light emitting element is fixed and protected by a resin mixed with a fluorescent substance, the light emitted from the light emitting element is efficiently wavelength-converted, and the wavelength-converted light is approximately 18
It is output as light that is illuminated over a wide range that can be viewed from a 0 degree hemisphere.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a light emitting diode according to the present invention.

FIG. 2 is an enlarged view of a portion a surrounded by a broken line shown in FIG.

FIG. 3 is a view showing characteristics of a resin 8;

FIG. 4 is a diagram illustrating a method of applying a resin 8;

FIG. 5 is a diagram illustrating a method of dropping a resin 8;

FIG. 6 is a diagram schematically showing a state in which a fluorescent substance 9 precipitates.

FIG. 7 is a diagram (1) showing an example of a pin shape suitable for resin dripping.

FIG. 8 is a diagram (2) showing an example of a pin shape suitable for resin dripping.

FIG. 9 is a diagram (3) showing an example of a pin shape suitable for resin dripping.

FIG. 10: LE having a pin head larger than the resin application area
The figure which showed the example of a structure of D.

FIG. 11 illustrates an example of a substrate on which a light-emitting element is directly mounted.

FIG. 12 is a diagram showing a configuration example of an LED in which a plurality of light emitting elements are mounted on a substrate.

FIG. 13 is a diagram showing a schematic configuration of a conventional LED.

FIG. 14 is an enlarged view of a portion b surrounded by a broken line in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light emitting diode (LED) 2 Light emitting element 3 Substrate 4-1 and 4-2 Lead pin 5 Pin 6-1 and 6-2 Wire 7 Resin 8 Resin 9 Fluorescent substance 12 Light emitting element 15 Pin 18 Resin 19 Fluorescent substance 20 Resin 22 Light emission Element 25 Pin 28 Resin 29 Fluorescent substance 32 Light emitting element 35 Pin 35a Surrounding 38 Resin 39 Fluorescent substance 41 Light emitting diode (LED) 42 Light emitting element 44-1 and 44-2 Lead pin 46-1 and 46-2 Wire 48 Resin 52 Light emitting element 53 substrate 53a protrusion 58 resin 59 fluorescent substance 62 light emitting element 63 substrate 63a groove 68 resin 69 fluorescent substance 71 light emitting diode (LED) 72 light emitting element 73 substrate 74-1, 74-2 lead pin 78 resin 100 nozzle

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4M109 AA01 BA01 BA03 CA06 DA07 DB16 EA01 EB18 EC11 EE12 EE15 GA01 5F041 AA14 CA12 DA07 DA12 DA13 DA18 DA20 DA25 DA26 DA43 DB01 EE25

Claims (19)

[Claims] 1. A pin having a head having a flat portion, a light emitting element mounted on the center of the head of the pin, and a wavelength of light that covers the light emitting element and emits light from the light emitting element. A light emitting diode, comprising: a first resin that selectively mixes a wavelength conversion substance to be converted into at least a portion adjacent to the light emitting element. 2. The light emitting diode according to claim 1, wherein the wavelength conversion material is a fluorescent material. 3. The light emitting diode according to claim 1, wherein the first resin has a hemispherical shape having a diameter equal to or smaller than a diameter of the head of the pin. 4. The light emitting diode according to claim 1, wherein the head of the pin has a dish shape having a flat portion in the center. 5. The light emitting diode according to claim 1, wherein the head of the pin has a bank-shaped surrounding portion on a circumference of an edge thereof. 6. The light emitting diode according to claim 5, wherein the surrounding portion is formed of a second resin different from the first resin. 7. A substrate, a light-emitting element mounted on the substrate, and a wavelength conversion material that covers the light-emitting element and converts a wavelength of light emitted from the light-emitting element is brought close to at least the light-emitting element. A light emitting diode comprising: a first resin selectively mixed in a portion. 8. The light emitting diode according to claim 7, wherein the wavelength conversion material is a fluorescent material. 9. The light emitting diode according to claim 7, wherein the first resin has a hemispheric shape protruding from a mounting position of the light emitting element. 10. The light emitting diode according to claim 7, wherein the substrate has a groove around a position where the light emitting element is mounted. 11. The light emitting diode according to claim 7, wherein the mounting position of the light emitting element is a protrusion on the substrate. 12. A step of mounting a light emitting element on a pin head or a substrate on which a flat portion is formed, and mixing the light emitting element with a wavelength conversion substance for converting a wavelength of light emitted from the light emitting element. The method includes at least a step of dropping a liquid thermosetting resin, a step of moving the wavelength conversion substance to a position near the light-emitting element in the thermosetting resin, and a step of heating and curing the hemisphere. A method for manufacturing a light emitting diode, comprising: 13. The method of moving the wavelength converting substance to the vicinity of the light emitting element in the thermosetting resin is performed by precipitating the wavelength converting substance in the thermosetting resin. A method for manufacturing a light emitting diode according to claim 12. 14. The wavelength conversion substance according to claim 12, wherein the wavelength conversion substance is a fluorescent substance.
A method for manufacturing the light-emitting diode according to the above. 15. The step of moving the wavelength converting substance to the vicinity of the light emitting element in the thermosetting resin, the method comprising: moving the wavelength converting substance to the vicinity of the light emitting element in the thermosetting resin. 13. The method for manufacturing a light emitting diode according to claim 12, wherein the thermosetting resin is formed into a hemisphere using the surface tension. 16. A step of mounting a light emitting element on a pin head or a substrate on which a flat portion is formed, and mixing the light emitting element with a wavelength conversion substance for converting a wavelength of light emitted from the light emitting element; A step of applying a resin whose viscosity is reduced by heating and which is cured by further heating; heating the resin to reduce the viscosity, and applying the wavelength converting substance to the light emitting element in the resin having the reduced viscosity. A method for manufacturing a light emitting diode, comprising: at least a step of moving the resin to a vicinity thereof, and a step of further heating and curing the resin. 17. Heating the resin to reduce its viscosity,
17. The light emitting diode according to claim 16, wherein the step of moving the wavelength converting substance to a position near the light emitting element in the resin having reduced viscosity is performed by causing the wavelength converting substance to precipitate in the resin. Manufacturing method. 18. The device according to claim 16, wherein the wavelength conversion material is a fluorescent material.
A method for manufacturing the light-emitting diode according to the above. 19. Heating the resin to reduce viscosity,
The step of moving the wavelength conversion substance to the vicinity of the light emitting element in the resin having the reduced viscosity includes heating the resin to reduce the viscosity, and emitting the wavelength conversion substance in the resin having the reduced viscosity. 2. The method according to claim 1, wherein the resin having reduced viscosity is formed into a hemisphere by utilizing its surface tension while being moved to the vicinity of the element.
7. The method for manufacturing a light emitting diode according to item 6.