JP3649748B2 - Light emitting diode lamp - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a light emitting diode lamp using a plurality of light emitting diodes.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a light emitting diode lamp using a plurality of light emitting diodes is shown in, for example, Japanese Patent Laid-Open No. 4-137369 as shown in the sectional view of FIG. 7 and the plan view of FIG. In these drawings, two insulating bases 72 are placed on the placement surface of a can 71, and blue light emitting diodes 73 are placed thereon via a conductive adhesive. A red light emitting diode 74 and a green light emitting diode 75 are mounted on the can 71. Wiring is provided at each insulating stand 72, each light emitting diode 73, 74, 75, can 71, and terminals 76 to 80.
[0003]
[Problems to be solved by the invention]
Therefore, in the above-described lamp, two light emitting diodes 73, 74, and 75 are provided with two light emitting junction surfaces so as to have the same height and to ensure insulation between the can 71 and the blue light emitting diode 73. Although the insulating stand 72 is provided, it takes time to work because the two are fixed separately. In addition, fixing the blue light-emitting diode 73 on the insulating base 72 takes time because it is manually performed, and the blue light-emitting diode 73 is liable to be displaced. Further, in order to obtain white light in the above-mentioned lamp, a total of three or more red, green, and blue light emitting diodes are required by the three primary color mixing method. Therefore, the number of light emitting diodes is large, and the number of terminals and wirings is large. Therefore, there is a second disadvantage that the cost is high and the power consumption is large. In view of such drawbacks, the present invention provides a light-emitting diode lamp in which an insulating base and a light-emitting diode are easily assembled and the number of light-emitting diodes is smaller than that of the conventional one.
[0004]
[Means for Solving the Problems]
The light-emitting diode lamp of the present invention is a light-emitting diode lamp comprising a lead, a plurality of light-emitting diodes, and a translucent resin covering the plurality of light-emitting diodes. It has a cup shape having a placement portion and a reflection portion at the tip, and an insulating stand is placed on the placement portion via an adhesive, and there are steps on the surface of the insulation stand corresponding to the plurality of diodes. And a conductive pattern for the plurality of light emitting diodes is formed, and the plurality of light emitting diodes are placed on the conductive pattern of the insulating base via a conductive adhesive. .
According to a second aspect of the present invention, the light emitting diode is a blue light emitting diode and a yellow light emitting diode.
[0005]
[Action]
As described above, the present invention mounts a plurality of light emitting diodes on a conductive pattern of an insulating base having a step corresponding to the light emitting diode on the surface, so that it is assembled compared to a method in which each insulating base is fixed. The work time required for is shortened. In particular, since the conductive pattern corresponding to the plurality of light emitting diodes is formed on the insulating base, it is easy to assemble the plurality of light emitting diodes. In addition, since a plurality of light emitting diodes are arranged in the cup-shaped portion of the lead, directivity and color mixing can be improved. By turning on both the blue and yellow light emitting diodes, blue light and yellow light are mixed to obtain white light. Therefore, the number of light emitting diodes is reduced as compared with the conventional three primary color mixing method.
[0006]
【Example】
A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view of a light-emitting diode lamp according to the present embodiment, and FIG. 2 is a plan view of the lamp. In these drawings, the lead 1 is made of a metal plate such as an iron plate, and is composed of an end portion 2, a placement portion 3, and a reflection portion 4.
[0007]
The insulating stand 5 is made of silicon containing a low concentration impurity of, for example, about 10 ¹¹ cm ⁻³ , is rectangular when viewed from the plane, and has a stepped height when viewed from the side. Conductive patterns 6 and 7 are formed on the surface of the insulating table 5 and are electrically separated. The conductive patterns 6 and 7 have notches 8 and 9, respectively, and the electrodes are partially removed. This is because when the light emitting diode is placed on the insulating table 5 by an automatic machine, it is easy to recognize the placement location and to ensure an accurate placement position. The insulating stand 5 is placed on the placement portion 3 of the lead 1 via a conductive adhesive 10.
[0008]
The blue light-emitting diode 11 is formed on an N-type substrate 12 (layer thickness: about 100 μm) made of silicon carbide (SiC) doped with nitrogen and an N-type epitaxial layer 13 (layer thickness: about 100 μm) doped with nitrogen and aluminum. 9 μm) and a P-type epitaxial layer 14 (layer thickness of about 5 μm) made of silicon carbide to which aluminum is added, and a front electrode 15 and a back electrode 16 are formed.
[0009]
As described above, the light-emitting junction surface formed by the N-type epitaxial layer 13 and the P-type epitaxial layer 14 is provided on the side close to the back electrode 16. This is to increase the light extraction efficiency by reducing the distance between the light emitting junction surface and the surface electrode 15 so that the emitted light is not blocked by the surface electrode 15. The blue light emitting diode 11 is placed on the conductive pattern 6 of the insulating table 5 via the solder 17.
[0010]
The yellow light-emitting diode 18 is formed on a N-type substrate 19 (layer thickness of about 280 μm) made of gallium phosphide (GaP), and tellurium is added to GaAs _X P _1-X (x is gradually away from the N-type substrate 19). N-type gradient layer 20 (having a thickness of about 30 μm) composed of 0 to 0.15), N-type epitaxial layer 21 (layer thickness of about 15 μm) composed of GaAs _0.15 P _0.85 doped with tellurium, and nitrogen and tellurium. consisting GaAs _0.15 P _0.85, which is added N-type epitaxial layer 22 P-type epitaxial layer 23 made of GaAs _0.15 P _0.85 to (layer thickness about 15 [mu] m) and zinc was added (layer thickness about 5 [mu] m) is formed, the surface electrode 24 And the back electrode 25 is formed.
[0011]
The step of the insulating base 5 is set so that the height of the light emitting junction surface formed by the N type epitaxial layer 22 and the P type epitaxial layer 23 of the yellow light emitting diode 18 and the light emitting junction surface of the blue light emitting diode 11 are substantially the same. The size is decided.
[0012]
The other leads 26 and 27 are made of a metal plate such as an iron plate and are provided outside the reflecting portion 4 of the lead 1. The thin metal wires 28, 29, 30, 31 are respectively connected between the other lead 26 and the blue light emitting diode 11, between the lead 1 and the conductive pattern 6, and between the pattern electrode 6 and the yellow light emitting diode 18, and conductive. It is applied between the pattern 7 and another lead 27. The translucent resin 32 is made of, for example, an epoxy resin mixed with a light diffusing agent, and is formed so as to cover at least the blue and yellow light emitting diodes 11 and 18. The light emitting diode lamp 33 of the present embodiment is constituted by these components.
[0013]
As described above, since the blue and yellow light emitting diodes 11 and 18 are common to the anode, an anode voltage is applied to the lead 1 and a cathode voltage is applied to the other leads 26 and 27.
[0014]
Next, the color emitted by the light emitting diode lamp of this embodiment will be described with reference to the chromaticity diagram of FIG. The horizontal axis and the vertical axis are the x coordinate and y coordinate in the CIE (International Commission on Illumination) 1931 chromaticity diagram, respectively. In this figure, a is a light emission color measured when the blue light-emitting diode 11 is lit alone, measured with a visual colorimeter. An actually measured emission color when the yellow light emitting diode 18 is lit alone is indicated by b. The light emission color when both the light emitting diodes 11 and 18 are turned on simultaneously is indicated by c, and the x coordinate is 0.3 and the y coordinate is 0.31. In the above CIE1931 chromaticity diagram, the range indicated by d (x coordinate of the center value is 0.33, y coordinate is 0.33) is white. Therefore, the actual measurement value c is in the white range.
[0015]
Further, a second embodiment of the present invention in which the material of each light emitting diode is different from that of the first embodiment will be described with reference to FIGS. FIG. 3 is a cross-sectional view of the light-emitting diode lamp of this embodiment, and FIG. 4 is a plan view thereof. In these drawings, the insulating base 34 is made of, for example, silicon containing low-concentration impurities, and has different heights in a stepped manner. Conductive patterns 35 and 36 are formed on the surface thereof, and are electrically separated. A cutout 37 is formed in the conductive pattern 35 and cutouts 38 and 39 are formed in the conductive pattern 36 so that the automatic machine can easily recognize them. The insulating table 34 is placed on the placement unit 3 via the conductive adhesive 10.
[0016]
The blue light-emitting diode 40 includes a buffer layer 42 made of aluminum nitride, an N ⁺ -type gallium nitride layer 43, an N-type gallium nitride layer 44, and a gallium nitride layer 45 to which low-concentration impurities are added. The anode electrode 46 is in contact with the gallium nitride layer 45 and the cathode electrode 47 is in contact with the N ⁺ type gallium nitride layer 43. The anode electrode 46 and the cathode electrode 47 are respectively placed on the conductive patterns 35 and 36 of the insulating base 34 via a conductive adhesive.
[0017]
The yellow light emitting diode 48 is made of an N-type cladding layer 50 made of N-type InGaAlP added with silicon, an active layer 51 made of InGaAlP, and a P-type InGaAlP added with low-concentration zinc on an N-type gallium arsenide substrate 49. It comprises a P-type cladding layer 52, a P-current diffusion layer 53 made of P-type GaAlAs added with high-concentration zinc, a front electrode 54, and a back electrode 55.
[0018]
The insulating base 34 is formed so that the light emitting junction surface formed by the N-type gallium nitride layer 44 and the gallium nitride layer 45 of the blue light emitting diode 40 is substantially the same as the active layer 51 of the yellow light emitting diode 48. The size of the step is determined. Metal thin wires 56, 57, and 58 are wired. In these drawings and FIGS. 1 and 2, the same reference numerals indicate the same thing.
[0019]
Next, the color of light emitted from the light emitting diode lamp of this embodiment will be described with reference to FIG. E and f indicate the measured emission colors when the blue light emitting diode 40 and the yellow light emitting diode 48 are individually turned on. The light emission color when these are simultaneously turned on is in the white range indicated by d.
[0020]
Further, a third embodiment of the present invention in which the material of the blue light emitting diode is different from that of the first embodiment will be described with reference to the sectional view of FIG. In this figure, an insulating table 59 is made of silicon containing low-concentration impurities, for example, has a stepped height, and a conductive pattern 60 is continuously formed on the surface thereof. The insulating table 59 is mounted on the mounting unit 3 via the conductive adhesive 10.
[0021]
The blue light emitting diode 61 has a substrate 62 made of N-type zinc selenide (ZnSe) having a layer thickness of about 250 μm, an N-type epitaxial layer 63 (layer thickness of about 5 μm) made of chlorine-added N-type zinc selenide, and lithium. The P-type epitaxial layer 64 (layer thickness is about 1 μm) made of P-type zinc selenide, the front surface electrode 65 and the back surface electrode 66 is constituted. The blue light emitting diode 61 is mounted on the mounting portion 3 via a conductive adhesive.
[0022]
The yellow light-emitting diode 18 made of the same material as that of the first embodiment is placed on the placement portion 3 via a conductive adhesive. In FIG. 1 and FIG. 1 and FIG. 2, the same number indicates the same thing. The step size of the insulating base 59 is determined so that the light emitting junction surface of the blue light emitting diode 61 is substantially the same height as the light emitting junction surface of the yellow light emitting diode 18. Both light emitting diodes are wired to the cathode common.
[0023]
Next, the emission color of the light emitting diode lamp will be described with reference to FIG. Measured colors of light emitted when the blue light-emitting diode 61 and the yellow light-emitting diode 18 are individually turned on are indicated by g and b, respectively. When these are simultaneously turned on, the emission color is in the white range indicated by d.
[0024]
As described above, since a plurality of light emitting diodes are mounted on the conductive pattern of one insulating table, the working time is quicker than the conventional method of fixing each insulating table. Further, by providing a notch in the conductive pattern, it becomes easy to recognize the placement location by an automatic machine, and the light emitting diode can be placed at an accurate position.
[0025]
Further, by changing the height of the insulating base on which each light emitting diode is mounted in a stepped manner, the light emitting junction surfaces of a plurality of light emitting diodes having different emission colors can be provided at substantially the same height. Therefore, since the light emitted from each light emitting diode is mixed near the light emitting source, the light of each other can be mixed well.
[0026]
More preferably, a blue light emitting diode made of silicon carbide, zinc selenide, or gallium nitride and a yellow light emitting diode made of gallium arsenide phosphide or gallium aluminum indium phosphide are provided and both are turned on so that blue light and yellow light are emitted. Mixed to obtain white light. Therefore, the number of light emitting diodes, the number of terminals, and the number of wirings are reduced as compared with the three primary color mixing method, and the cost is reduced.
【The invention's effect】
As described above, according to the present invention, since a plurality of light emitting diodes are mounted on the conductive pattern of the insulating base having a level difference corresponding to the light emitting diode on the surface, compared to the method of fixing each insulating base. Work time required for assembly. In particular, since the conductive pattern corresponding to the plurality of light emitting diodes is formed on the insulating base, it is easy to assemble the plurality of light emitting diodes. In addition, since a plurality of light emitting diodes are arranged in the cup-shaped portion of the lead, directivity and color mixing can be improved. By turning on both the blue and yellow light emitting diodes, blue light and yellow light are mixed to obtain white light. Therefore, the number of light emitting diodes is reduced as compared with the conventional three primary color mixing method.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a light emitting diode lamp according to a first embodiment of the present invention.
FIG. 2 is a plan view of a light emitting diode lamp according to a first embodiment of the present invention.
FIG. 3 is a cross-sectional view of a light emitting diode lamp according to a second embodiment of the present invention.
FIG. 4 is a plan view of a light emitting diode lamp according to a second embodiment of the present invention.
FIG. 5 is a cross-sectional view of a light emitting diode lamp according to a third embodiment of the present invention.
FIG. 6 is a chromaticity diagram of light emission colors in each light emitting diode lamp according to first, second and third embodiments of the present invention.
FIG. 7 is a cross-sectional view of a conventional light emitting diode lamp.
FIG. 8 is a plan view of a conventional light emitting diode lamp.
[Explanation of symbols]
1 Lead 5, 34, 59 Insulation base 6, 7, 35, 36 Conductive pattern 11, 40, 59 Blue light emitting diode 18, 48 Yellow light emitting diode 32 Translucent resin

Claims (2)

A light-emitting diode lamp comprising a lead, a plurality of light-emitting diodes, and a translucent resin covering the plurality of light-emitting diodes, wherein the lead has a cup shape having a placement part and a reflection part at its tip, An insulating table is mounted on the mounting portion via an adhesive, and a step is provided on the surface of the insulating table corresponding to the plurality of diodes, and a conductive pattern for the plurality of light emitting diodes is formed. The light-emitting diode lamp is characterized in that the plurality of light-emitting diodes are placed on the conductive pattern of the insulating base via a conductive adhesive. The light emitting diode emitting diode lamp of claim 1, wherein a is a blue light emitting diode and the yellow light emitting diode.

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