JPH05226699A - Light emitting element - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a light emitting device having a multi-layer structure with high brightness and excellent monochromaticity. According to the present invention, a PN junction layer and a P serving as a light emitting region are formed.
It includes a laminated structure with a reflection layer that reflects the light emitted from the PN junction layer with the N junction layer interposed therebetween, and the light obtained from the PN junction layer is converted into P
A light emitting diode 2 taken out from the end face of the N junction layer, and a PN
The mounting members 3a and 3b for mounting the light emitting diode 2 substantially parallel to the bonding surface of the bonding layer and the light-transmissive envelope 5 for sealing at least the light emitting diode 2 are configured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device which extracts light from an end face of a light emitting layer in a light emitting diode and emits the light.

[0002]

2. Description of the Related Art As a conventional light emitting diode (LED) lamp used for a display light source or the like, there is, for example, one shown in FIG.

In FIG. 8, an LED lamp 101 includes a semiconductor light emitting diode 102 and a light emitting diode 10 thereof.
A lead frame 1 on which the 2 is placed and which also serves as the energizing path
03, light emitting diode 102 and lead frame 103
A wire 104 that electrically connects the light emitting diode 102 and the lead frame 103 is provided, and a light-transmissive envelope 105 that seals part of the lead frame 103 is provided. Light emitting diode 1
In order to improve the performance, 02 has a multi-layer structure including a PN junction and is often used.

In such an LED lamp 101,
The light obtained at the PN junction of the light emitting diode 102 once diverges substantially uniformly. The diverged light is repeatedly refracted and reflected at the optical interface in the multilayer structure. After that, the light reaches the interface of the light emitting diode 102 through various paths and is diffused to the outside in four directions.

In this way, the light extracted from the light emitting diode 102 has various wavelength distributions depending on the path through which it passes due to the wavelength selectivity in light absorption of each layer of the light emitting diode 102. In particular, the light that travels a long distance in the active layer having a large light absorption rate and is emitted to the outside from the vicinity of the active layer on the end face tends to have a wavelength distribution that fluctuates toward the longer wavelength side than light that travels along other paths. ..

Therefore, the light emitting diode 102 described above is used.
In this case, the light emitted in the lateral direction from the end face of the laminated structure and the light emitted in the vertical direction have different wavelengths, which causes variations in the emission color.

Further, since the light extracted from the light emitting diode 102 described above is emitted in all directions, it is extremely difficult to effectively use all the emitted light.

Further, of the light obtained in the vicinity of the PN junction, the light traveling in the stacking direction (vertical direction) is absorbed by the electrode formed in the outermost layer, so that the light extraction efficiency is low. .. This means that light absorption by the electrode occurred even when the electrode was provided only on one side of the outermost layer.

[0009]

As described above,
L having a multi-layered light emitting diode as shown in FIG.
In the ED lamp, the traveling path of the light obtained by the light emitting diode in the diode is unspecified, so that the wavelength distribution of the emission wavelength is broadened and the monochromaticity is impaired.

Further, since the light obtained by the light emitting diode is diffused in all directions and the light extraction efficiency is lowered due to the absorption of the light by the electrodes, it is extremely difficult to realize high brightness.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a light emitting device having a multi-layer structure, which has high brightness and excellent monochromaticity.

[0012]

In order to achieve the above object, the present invention is a laminate of a PN junction layer which becomes a light emitting region and a reflection layer which reflects light emitted from the PN junction layer with the PN junction layer sandwiched therebetween. A light emitting diode including a structure, which extracts light obtained from the PN junction layer from an end surface of the PN junction layer, a mounting member for mounting the light emitting diode substantially parallel to the junction surface of the PN junction layer, and at least the light emitting diode And a light-transmissive envelope that seals.

[0013]

In the above structure, the present invention limits the traveling path of light in the light emitting diode by extracting the light from the end face of the PN junction layer of the light emitting diode.
I try to avoid the light absorber and take out the light.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of an LED lamp according to an embodiment of the present invention, and FIG. 2 is a sectional view showing the structure of the light emitting diode shown in FIG.

Referring to FIG. 1, in the LED lamp 1, the multi-layered light emitting diode 2 shown in FIG. 2 is mounted on a flat lead frame 3a such that the stacking surface and the mounting surface are substantially parallel to each other, and a wire is formed. 4 is connected and connected to the lead frame 3b by the light emitting diode 2 and the lead frames 3a and 3b.
Is partially sealed by an envelope 5 made of resin.

The light emitting diode 2 is, as shown in FIG.
A buffer layer 12 made of n-GaAs, and a light reflection layer 1 in which about 20 layers each of an n-GaAlP layer and an n-InAlP layer are alternately laminated on an n-GaAs substrate 11.
3, clad layer 14 made of n-InGaAlP, In
Active layer 15 made of GaAlP and serving as a light emitting layer, P-In
A cladding layer 16 made of GaAlP, a light-reflecting layer 17 made by alternately laminating about 20 layers of P-InAlP layers and P-InGaAlP layers, and a contact layer 18 made of P-GaAs are laminated in order, and an n-GaAs substrate is formed. 11
And an electrode 19 is formed on each of the contact layers 18 made of P-GaAs.

The light emitting diode 2 having such a multilayer structure
The one electrode 19 is mounted by being attached to the lead frame 3a with a conductive adhesive such as silver epoxy. The light emitting diode 2 mounted and adhered on the lead frame 3a is
The other electrode 19 and the lead frame 3b are connected and connected by, for example, thermocompression bonding of a gold wire 4. The light-emitting diode 2 placed on the lead frame 3a and connected to the lead frame 3b is inserted into a mold jig filled with a light-transmissive epoxy resin and heat-cured. After heat curing, the jig for the mold is removed, and the light emitting diode 2 is sealed together with a part of the lead frames 3a and 3b by an envelope 5 made of resin and having a lens integrally formed in the irradiation direction. , 3b are cut and formed into desired shapes to complete.

The LED lamp 1 manufactured in this way
Is the reflection layers 13 and 17 in which the light obtained in the active layer 15 of the light emitting diode 2 is arranged so as to sandwich the active layer 15.
The light is reflected by the active layer 15, travels in the active layer 15 while being confined in the active layer 15, and is extracted from the end surface of the active layer 15 to the outside of the light emitting diode 2. In this way, the light emitted from the four end faces of the light emitting diode 2 travels in the sealing resin, and a part of the light is refracted at the interface between the sealing resin and the outside air, and the lens formed at the front part The light is focused in the main irradiation direction and is irradiated to the outside.

As described above, since all the light obtained by the light emitting diode 2 is extracted from the end face of the active layer 15,
The traveling path of light is limited and the emission wavelengths are aligned. Therefore, the azimuth dependence of the wavelength distribution in the emitted light is reduced, and the monochromaticity is improved.

Further, since the electrodes do not absorb the light, the light extraction efficiency is enhanced and high brightness can be realized.

3 to 7 are sectional views showing the structure of an LED lamp according to another embodiment of the present invention. Note that FIG.
In the LED lamp of the embodiment shown in FIG. 7 to FIG. 7, the same light emitting diode 2 as that shown in FIG. 1 is used, and the same reference numerals as those in FIG. 1 are the same.

The feature of the embodiment shown in FIG. 3 is that
In the lead frame 21 on which the light emitting diode 2 is mounted, a part of the light emitting diode 2 is parabolically surrounded and a reflection surface 22 whose wall surface is a parabolic surface is provided. The light emitted in the direction opposite to the main irradiation direction is reflected toward the main irradiation direction.
In such an embodiment, the light converging property is improved and the amount of light in the main irradiation direction can be increased.

The feature of the embodiment shown in FIG. 4 is that
It differs from the embodiment shown in FIG. 3 in that the wall surface of the reflecting surface 23 is perpendicular to the mounting surface. In such an embodiment, the light converging property in the direction substantially parallel to the mounting surface is improved. Since the light extracted from the light-emitting diode 2 travels in a direction substantially parallel to the mounting surface, even if the light-collecting property in the direction substantially parallel to the mounting surface is improved, as shown in FIG. It is possible to obtain the same effect as that of the embodiment shown.

The feature of the embodiment shown in FIG. 5 is that
The reflecting surface 25 is provided by bending the lead frame 24 on which the light emitting diode 2 is mounted. Even in such an embodiment, it is possible to provide an LED lamp provided with a reflection surface which is inexpensive and highly productive, while providing the same effects as those of the above-mentioned embodiment and having a reflection surface easily formed.

The feature of the embodiment shown in FIG. 6 is that
A convex lens is provided on the envelope 26, and the lens is formed so as to be a part of a sphere or an ellipsoid, and the center of the lens is located on a substantially extended surface of the active layer 15 in the light emitting diode 2. ..

The feature of the embodiment shown in FIG. 7 is that
A convex lens is provided on the envelope 27, and the lens is a part of a cylinder or an elliptic cylinder, and the central axis thereof is the light emitting diode 2.
It is formed so as to be substantially perpendicular to the surface of the active layer 15 in.

In the embodiment shown in FIG. 6 or 7,
The light converging property in the main irradiation direction is improved, and the brightness can be increased.

The embodiment shown in FIG. 6 or 7 may be carried out in combination with the above-mentioned embodiment.

[0030]

As described above, according to the present invention, the light is extracted to the outside from the end face of the PN junction layer in the light emitting diode while avoiding the electrode, so that the traveling path of the light is limited and the light is emitted. The wavelengths are aligned and monochromaticity is improved. Further, since the electrodes do not absorb light, high brightness can be realized.

Further, by providing a lens on the reflecting surface or the envelope, the light converging property is improved and it is possible to contribute to the improvement of the brightness.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a light emitting device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a structure of a light emitting diode in the light emitting element shown in FIG.

FIG. 3 is a diagram showing a structure of a light emitting device according to another embodiment of the present invention.

FIG. 4 is a diagram showing a structure of a light emitting device according to another embodiment of the present invention.

FIG. 5 is a diagram showing a structure of a light emitting device according to another embodiment of the present invention.

FIG. 6 is a view showing a structure of a light emitting device according to another embodiment of the present invention.

FIG. 7 is a diagram showing a structure of a light emitting device according to another embodiment of the present invention.

FIG. 8 is a diagram showing a structure of a conventional light emitting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Light emitting diode 3a, 3b, 21, 24 Lead frame 4 Wire 5, 26, 27 Envelope 11 GaAs substrate 12 Buffer layer 13, 17 Light reflection layer 14, 16 Clad layer 15 Active layer 18 Contact layer 19 Electrode 22,23,25 Reflective surface

Claims (6)

[Claims] 1. A laminated structure of a PN junction layer which becomes a light emitting region and a reflective layer which reflects the light emitted from the PN junction layer with the PN junction layer sandwiched between the PN junction layer and the light obtained from the PN junction layer. A light emitting diode that is taken out from the end face of the device, a mounting member that mounts the light emitting diode substantially parallel to the bonding surface of the PN junction layer, and a light-transmissive envelope that seals at least the light emitting diode. Characteristic light emitting element. 2. The light emitting device according to claim 1, wherein the mounting member is provided with a reflecting member that reflects a part of the light emitted from the light emitting device. 3. The reflection member surrounds a part of the light emitting element in a parabolic shape, and the reflection surface is a parabolic surface or a surface perpendicular to the mounting surface. Light emitting element. 4. The light emitting device according to claim 1, wherein the mounting member is provided with a stepped reflecting surface formed by bending a part of the mounting member. 5. The light emitting device according to claim 1, 2, 3, or 4, wherein the envelope is provided with a convex lens. 6. The convex lens has a shape of a part of a sphere, a part of an ellipsoid, a part of a cylinder, or a part of an elliptic cylinder. Light emitting element.