JPH08330635A - Light emitting device - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a light-emitting device using a molded light source to downsize the entire device and obtain a high-quality luminous flux. A light-emitting device comprising a light-emitting element covered with a window member on an electronic substrate, and an optical element for converting a light beam from the light-emitting element into a predetermined state and emitting the light beam, wherein the window member and the optical element are provided. The space between them was filled with transparent resin.

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, and more particularly to a laser diode or a light emitting diode (LE) on an electronic substrate.
The present invention relates to a light emitting device having a structure in which a light emitting element such as D) and an optical element for converting a light beam emitted from the light emitting element into a predetermined light beam such as condensing or diffracting and emitting the light beam are miniaturized. .

[0002]

2. Description of the Related Art Conventionally, a light emitting device using a light emitting element such as a laser diode or a light emitting diode (LED) is a CD.
It is used in optical data recording devices, such as optical communication devices and optical measuring devices.

FIG. 5 is a schematic view of a main part of a light emitting device LGT of a metal CAN package in which a light extraction surface of a conventional light emitting element LGTa is covered with a transparent member W. In the figure, CB is an electronic substrate, and CP1 and CP2 are circuit patterns, which are provided on the electronic substrate CB. LGTa is a light emitting element, and is connected to the circuit patterns CP1 and CP2 via the bond wire BW and the lead R.

CAN is a wall cylinder that protects the light emitting element LGTa. W is a transparent member. The light emitting element LGTa is housed in the space formed by the transparent member W and the wall cylinder CAN. D is an optical element having a light-collecting function, and is a light emitting element LG
The light flux from Ta is condensed and guided in a predetermined direction.

[0005]

In the conventional light emitting device, since the luminous flux from the light emitting element is taken out through the glass plate (transparent member), the unevenness of the light quantity, the scattering and the disturbance of the luminous flux are relatively small, and the luminous flux is emitted. The quality is excellent. Therefore, a light emitting device using a metal CAN package having a diameter of about 5 mm is often used.

On the other hand, recently, there has been a demand for a light emitting device which is downsized as a whole. When a metal CAN package is used as the light emitting device, it is difficult to reduce the size because of the structure. On the other hand, since the size of the light emitting element such as the LED itself is a chip size of several 100 μm, the size of the entire light emitting device can be reduced by using the resin mold packaging technology.

However, since the resin mold package is produced by a molding technique such as injection using various metal molds, minute irregularities are likely to occur on the resin surface. For this reason, the light flux extracted through these surfaces (window member surface) is scattered, the optical path is deviated, and the wavefront is disturbed, so that the desired optical characteristics can be obtained even after combining high-precision optical elements. There was a problem that it was difficult.

The present invention effectively reduces the light scattering and the wavefront disturbance due to the unevenness of the window member which tends to occur when the size of the entire device is reduced by using the resin mold package, and the high-quality light flux is generated. An object is to provide a light emitting device that can emit light.

[0009]

A light emitting device of the present invention is provided with a light emitting element covered with a window member on an electronic substrate, and an optical element for converting a light beam from the light emitting element into a predetermined state and emitting the light beam. In the light emitting device, the space between the window member and the optical element is filled with a transparent resin.

Particularly, in the optical element, the transparent resin side is a flat surface or a curved surface and the opposite side is a curved surface or a diffraction grating surface, and the refractive index of the window member material and the transparent resin material are different from each other. It is characterized in that the refractive indices are substantially equal.

[0011]

Embodiment 1 FIG. 1 is a sectional view of the essential portions of Embodiment 1 of the present invention. In the figure, LGT is a resin mold type light emitting diode and has a light emitting portion LGTa connected by a bond wire. W is a transparent window portion (window member), which covers the light emitting diode LGT. CB is a printed circuit board (electronic board), and circuit patterns CP1 and CP2 are provided on the surface thereof.
Are formed. The circuit patterns CP1 and CP2 are electrically and mechanically connected to the light emitting diode LGT covered with the transparent window portion W provided on the printed circuit board CB with cream solder or the like via a bond wire or a lead wire.

Reference numeral H denotes a cylindrical or rectangular wall member, which surrounds the light emitting diode LGT and is fixed to the printed circuit board CB. G is a transparent substrate, which is made of a glass material, a plastic material, or the like, and is placed on the wall-shaped member H. The printed board CB, the transparent board G, and the wall-shaped member H form a sealed space in which the light emitting diode LGT is located (light emitting diode space). L is an optical element (lens) such as a spherical lens, a cylindrical lens, or a toric lens, which is provided on the transparent substrate G and collects a light beam from the light emitting surface LGTa of the light emitting diode LGT and guides it in a predetermined direction. ing.

In this embodiment, the lens L and the transparent substrate G may be integrally formed of the same material by molding or the like.

MO is a transparent resin and fills the inside of the light emitting diode space. The transparent resin MO is the transparent window W
It is preferable to use a material having substantially the same refractive index as that of the material (within ± 10%) because the light flux can be efficiently guided.

In this embodiment, a transparent liquid or a transparent gas having the same refractive index may be used instead of the transparent resin MO.

In the present embodiment, by filling the inside of the light emitting diode space with the transparent resin MO with the above-described structure, the irregularities on the surface of the window W or the light transmitting surface of the transparent substrate G are filled with the transparent resin MO. , Thereby preventing the light from being scattered on each surface and allowing the light flux from the light emitting diode LGT to pass through the lens L.
The light is efficiently guided in a predetermined direction.

In particular, in this embodiment, the light exit surface is filled with the transparent resin MO filled with the irregularities of the window W of the resin-molded light emitting diode LGT and the optical boundary surface is substantially (glass) plate-like. The surface accuracy is ensured and the turbulence of the light flux is effectively prevented.

2 to 4 are cross-sectional views of the essential portions of Embodiments 2 to 4 of the present invention. In the figure, the same elements as those shown in FIG. 1 are designated by the same reference numerals. In Example 2 of FIG. 2, D is a transparent plate-shaped optical element having a diffraction grating Da and the like on one surface, and is made of a glass material, a plastic material, or the like.

In this embodiment, the optical element D is adhered and fixed to the upper surface of the window portion W that covers the light emitting diode LGT with a transparent resin MO such as an adhesive. The refractive index of the transparent resin MO is the light emitting element LG.
The refractive index of the material of the window portion W of T is substantially the same.

As described above, in this embodiment, the transparent resin MO having adhesiveness is sandwiched in the space between the window portion W and the optical element D so as to fix the both, and the window is the same as in the first embodiment. Department W
The light flux from the light emitting diode LGT is efficiently guided to the optical element D while diffracting the light flux by the diffraction grating Da, for example, while preventing the scattering of light due to the unevenness of the surface of the optical element D and the unevenness of the surface of the optical element D. There is.

The third embodiment shown in FIG. 3 is different from the second embodiment shown in FIG.
It is different only in that a plate-shaped transparent member (for example, an optical filter or a light splitting member having a half mirror surface inside) P bonded to each other is bonded and fixed with a transparent resin MO such as an adhesive. Other configurations are the same. Transparent resin MO
Is substantially the same as the refractive index of the material of the window portion W of the light emitting element LGT.

In this embodiment, the same effect as that of the second embodiment is obtained with the above-mentioned structure.

In Example 4 of FIG. 4, DL is an optical element, which is made of a resin-molded transparent member having a lens portion DLa on one side and a concave portion for accommodating the light emitting diode LGT on the other side. A light emitting diode LGT is housed in the recess. Then, the space formed by the recess, the window W, and the substrate CB is filled with the transparent resin MO. The refractive index of the transparent resin MO is substantially the same as the refractive index of the material of the window W of the light emitting element LGT.

In the present embodiment, it is possible to utilize the feature that the optical surface precision is more easily obtained in the mold for molding the single optical element DL as compared with the molding mold for the package in which the light emitting element is sealed with resin.

[0025]

As described above, according to the present invention, the space between the window member covering the light emitting element and the optical element is filled with the transparent resin, so that the size of the entire device can be reduced by using the resin mold package. It is possible to achieve a light emitting device that can effectively reduce light scattering and disturbance of the wavefront due to the unevenness of the window member that tends to occur when attempting to emit a high-quality light flux.

In particular, according to the present invention, for example, the unevenness of the window W of the resin-molded light emitting diode LGT on the light exit surface is filled with the transparent resin MO, and the optical interface has a substantially plate-like optical element. It is possible to obtain a light emitting device having a flat surface of D, ensuring the surface accuracy, and effectively preventing the disturbance of the light flux.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a second embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a third embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a conventional light emitting device.

[Explanation of symbols]

 LGT light emitting diode LGTa light emitting element MO transparent resin L lens H wall member W window member CB electronic substrate CP1, CP2 circuit pattern D optical element G, P transparent substrate

Claims (3)

[Claims] 1. A light emitting device comprising an electronic substrate, a light emitting element covered with a window member, and an optical element for converting a light beam from the light emitting element into a predetermined state and emitting the light beam, the window member and the optical element. A light emitting device characterized in that a space between and is filled with a transparent resin. 2. The light emitting device according to claim 1, wherein in the optical element, the transparent resin side is a flat surface or a curved surface, and the opposite side is a curved surface or a diffraction grating surface. 3. The refractive index of the material of the window member and the refractive index of the material of the transparent resin are substantially equal to each other.
Or the light emitting device of 2.