JPH01142695A - Light emitting diode - Google Patents

Abstract

PURPOSE: To stably maintain external radiation efficiency of light by taking a liquid or gelatinous light transparent material into the circumference of a light emitting element and eliminating a spacing between the crystal surface of the light emitting element and the light transparent material. CONSTITUTION: The light emitting element 2 mounted on a circuit board 1 is formed by fixing a dome-shaped solid material 4 composed of the translucent material, such as, for example, an epoxy resin, onto a circuit board 1 by a suitable adhering means. For example, transparent silicone oil is used for the liquid or gelatinous light transparent material 5 packed in the hollow part of the solid material 4. As a result, the formation of the spacing between the crystal surface of the light emitting element and the light transparent material enclosing the circumference thereof by the thermal stress, etc., at lighting does not arise and, therefore, the occurrence of the degradation in the external radiation efficiency of light is averted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to maintaining and maintaining the external radiation efficiency of light emitted by a light emitting element.
The present invention relates to a light emitting diode which is improved and has a reliable and stable electrical connection between a light emitting element and an electrode part.

[Prior art and its problems]

The light emitting element of a light emitting diode is generally made of a material with a high refractive index. For example, if we take GaAs+-xPx crystal as an example, its refractive index is 3.6 and the critical angle with respect to air is 16.
'', and if the shape of the crystal surface can be regarded as a plane when viewed from the bonding position (light emitting position), approximately 96% of the light reaching the surface
% is totally internally reflected.

Most of the light reflected internally is absorbed within the crystal and is not emitted to the outside. For this reason, conventional methods have been taken to alleviate the problem of internal reflection by coating the surface of the light emitting element with a transparent solid coating medium having a high refractive index. However, as shown in Figure 6, the interface between the crystal and air of the light emitting element! , is a flat surface, and as shown in FIG. The light emitted from position i1P is at an angle θ with respect to the crystal surface of the light emitting element. The light that enters within the range is not emitted to the outside. Therefore, as shown in FIG. 5, it has been proposed to cover the periphery of the light emitting element 51 in a hemispherical shape with a transparent coating medium 52 such as epoxy resin. In the same figure,
53 is a circuit board, and 54 is a wire. With such a structure, the interface between the coating medium 52 and air is no longer a flat surface, so that even light incident on the crystal surface of the light emitting element at an angle of 83 or less in FIG. 7 can be extracted as external radiation. be. FIG. 8 shows the state of light emission in a light emitting diode having such a structure.

However, when the light emitting element 51 is surrounded by a hemispherical solid coat medium 52 as shown in FIG. Gaps may occur. However, when such a gap occurs, not only does the efficiency of external radiation of light drop significantly, but also poor contact occurs between the wire and the circuit or between the wire and the light emitting element electrode, making it difficult to obtain a good electrical connection. The problem was that there was no.

[Failure to solve the problem]

The present invention aims to solve the above-mentioned problems, and provides a light emitting diode having the following structure.

That is, it has a light-emitting element, a lead part for supplying power to the light-emitting element, and a liquid or gel-like light-transmitting substance surrounding the light-emitting element, and the light-transmitting part is formed at least in part of the light-transmitting substance. The structure is enclosed and sealed with a solid material having a

In other words, by surrounding the light-emitting element with a liquid or gel-like light-transmitting material instead of surrounding it with a solid coating medium like in the past, the crystal surface of the light-emitting element and the light-transmitting material provided around it are This is to prevent gaps from forming between them.

〔Example〕

FIG. 1 shows an embodiment of a light emitting diode according to the present invention. 1 is a circuit board, 2 is a light emitting element mounted on the circuit board, and 3 is a wire. 4 is a dome-shaped solid material made of a translucent material such as epoxy resin (refractive index 1.5). This solid material 4 is fixed onto the circuit board 1 by suitable adhesive means. Reference numeral 5 denotes a liquid or gel-like light-transmitting substance filled in the hollow part of the solid material 4, such as transparent silicone oil (refractive index 1.6). Note that the solid material 4 may be entirely composed of a translucent material, but
Of course, parts unrelated to light emission, such as the attachment part to the circuit board 1, do not need to be made of a light-transmitting material. That is, it is sufficient that at least a portion thereof has a light-transmitting portion.

In a light-emitting diode with such a structure, no gap is created between the crystal surface of the light-emitting element and the surrounding light-transmitting material due to thermal stress during lighting, so the external radiation efficiency of light is prevented from decreasing. There is no invitation. Furthermore, a good electrical connection can be maintained without causing poor contact between the light emitting element, wire, and circuit. Furthermore, since the light-transmitting material surrounding the light-emitting element is sealed with a solid material, it can be selected without worrying about corrosion resistance, weather resistance, etc., and it is easy to obtain a material with a large refractive index and high transparency. It is also possible to improve the efficiency of emitting light to the outside. FIG. 2 shows the light emission state of the light emitting diode shown in FIG.

FIG. 3 shows another embodiment of the invention. In this example,
The light emitting element 2 is mounted on a transparent glass substrate 1 on which a fine line circuit is formed, and is electrically connected by wires 3. A reflective substrate 7 having a concave reflective surface 6 is attached to the light emitting surface side of the light emitting element 2 mounted on the transparent glass substrate 1, and the light emitted from the light emitting element 2 is once reflected by the concave reflective surface 6. The structure is such that it is radiated to the outside after the irradiation. A hollow portion surrounded by the concave reflective surface 6 is filled with a liquid or gel-like light-transmitting substance, such as transparent silicone oil 5 .

In addition to the advantages of the embodiment shown in FIG. 1, the light emitting diode with this structure has excellent light extraction efficiency because the direction of light emission is controlled within the light-transmitting material 5, and the light emitting surface is flat. It is characterized by its wide range of uses as a flat light source.

FIG. 4 shows the light emitting state of the light emitting diode.

(Effects of the Invention) As is clear from the above description, in the present invention, the light emitting element is surrounded by a liquid or gel-like light-transmitting substance, so that the crystal surface of the light-emitting element and the light-transmitting substance are closely connected. There is no gap between the wires.Therefore, the external radiation efficiency of light can be maintained stably, and there is no worry of wire breakage.

Furthermore, since the light-transmitting substance is sealed, it can be selected without worrying about weather resistance and corrosion resistance, making it easy to obtain a medium with a large refractive index and high transparency. Thereby, it is also possible to improve the external radiation efficiency of light.

[Brief explanation of the drawing]

1 and 3 are cross-sectional views of the light emitting diode according to the present invention, FIGS. 2 and 4 are state diagrams of light emission in the embodiments of FIGS. 1 and 3, respectively, and FIGS. 5 and 8 The figure is a cross-sectional view of a conventional light emitting diode and a diagram of the state of light emission, and FIGS. 6 and 7 are diagrams illustrating the state of refraction of light in the light emitting element crystal of the light emitting diode. 1 to 4, 1... circuit board, 2... light emitting element, 3... wire, 4... solid substance, 5... light transmitting material, 6...
Concave reflective surface. Figure 1, Figure 23, Figure 2, Figure 4, Figure 5, Figure O, 6, Figure 7, Figure 7, Figure 8.

Claims (4)

[Claims] (1) It has a light-emitting element, a lead portion for supplying power to the light-emitting element, and a liquid or gel-like light-transmitting material surrounding the light-emitting element, and the light-transmitting material is at least partially transparent. A light-emitting diode characterized in that it is sealed with a solid material having parts. (2) The interface between the liquid or gel-like light-transmitting substance surrounding the light-emitting element and the solid material sealing the light-transmitting substance is formed in a spherical shape with the light-emitting element at the center. A light emitting diode according to claim 1, characterized in that: (3) A concave reflective surface is provided on the light emitting surface side of the light emitting element to face the light emitting element, and after the light emitted by the light emitting element is once reflected by the concave reflective surface, it is reflected to the outside. 2. The light emitting diode according to claim 1, wherein the light emitting diode is configured to emit light. (4) The solid material sealing the light-transmitting substance has a flat plate shape, and the concave reflective surface connected thereto is a paraboloid of revolution. light emitting diode.