JP2781583B2 - Light emitting diode device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a light-emitting diode device, in particular, a light-emitting diode element having a light-emitting surface in a dome shape (hereinafter, also simply referred to as a chip). The present invention relates to a light emitting diode device sealed with a package made of a transparent resin.

[Conventional technology]

Light emitting diodes (light emitting diode elements) can be used as light sources for optical communications,
It is used as a light source for auto focus such as r). For example, "MINOLTA TECHNO REPORT" published by Minolta Camera Co., Ltd., No.
1, 1984, p. 26, an infrared LED (Light
Emitting Diode (LED) is used as a light source for automatic focusing of cameras. The document states, "To design a ranging module suitable for a compact camera,
It is necessary to shorten the focal length of both the receiving and receiving lenses and the distance between these lenses, but for that purpose, the light source light emitted from the infrared LED chip must be narrowed down. If the light source is large, the reflected light image returning to the light receiving element also becomes large, and the resolution of displacement detection is deteriorated. And that there is an LED in which a chip is polished in a dome shape, or an LED in which an extremely small spherical lens is arranged.

As a package structure of a light emitting diode device incorporating a light emitting diode element, a TO type can package structure and a resin package structure sealed with a transparent resin are known. Japanese Patent Application No. 60-271448 discloses an example of a can package having a dome-shaped light-emitting diode element (dome-shaped chip) therein, which is described in Ohm's National Tecnical Report, February 1988, Showa 63. Published on February 18, 2006, P20-P26 is an example of a can package that incorporates a flat (rectangular) LED chip with a spherical lens mounted on it, published by Press Journal Inc., “Semiconductor World
World) ”June 1982 issue, June 15, 1982, P13-
P36 describes an example in which a planar chip is covered with a transparent resin lens having a curved light extraction surface.

[Problems to be solved by the invention]

As described above, in recent years, in high-power applications of light-emitting diodes (for communication, for auto-focusing of cameras, VTRs, etc.), light-emitting diode elements in which the shape of the light-emitting surface of the element itself is dome-shaped, and planar (rectangular) Light emitting diodes in which a spherical lens is directly attached to the element have been developed. There is also a package structure in which elements are resin-molded so that a lens is formed of a transparent resin (resin).

On the other hand, the present applicant obtains a desired small light emission diameter by making the light extraction surface (light emission surface) hemispherical (dome-shaped), and also improves the light output (forward light output: luminance). . In the case of optical communication, as shown in the above document, the light emitting diameter is 30 μm, the dome height is 20 μm, and the dome radius is 200 μm due to the coupling property of the optical fiber. Also,
Light emission diameter of 100 to 3 for auto focus such as cameras
The size of the dome is 200 μm, the dome height is 200 μm, and the dome radius is 200 μm.

By the way, such a dome chip is fixed via a submount or the like and covered with a metal cap,
It is provided as a so-called can package structure.

Since the can package has better airtightness than the resin package, the can package has high reliability but tends to increase the manufacturing cost.

Therefore, the present inventor studied to adopt a structure in which the dome chip is sealed with a transparent resin for the purpose of reducing the manufacturing cost.

However, it has been clarified by the present inventors that the characteristics of the dome-shaped chip are lost if the dome-shaped chip whose optical characteristics such as light output and emission diameter are specified is packaged as it is in a transparent resin.

An object of the present invention is to provide a light emitting diode device in which optical characteristics such as a light emitting diameter and a light output are substantially the same as those of a built-in dome-shaped chip.

Another object of the present invention is to provide an inexpensive light-emitting diode device with high mass productivity in which optical characteristics such as a light emission diameter and a light output are substantially the same as those of a built-in dome-shaped chip.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[Means for solving the problem]

The outline of a representative invention among the inventions disclosed in the present application will be briefly described as follows.

In the light-emitting diode device of the present invention, a dome-shaped light-emitting diode element is fixed to one lead end surface of a pair of leads via a sub-mount, and the electrodes on the sub-mount of the dome-shaped light-emitting diode element are each a pair. Are electrically connected to the leading end surfaces of the leads. The tips of the pair of leads are covered with a resin package including the light emitting diode element and the wire, made of a transparent resin, and having a light extraction surface with a curvature of R.
Further, the curvature R of the light extraction surface of the resin package
And the distance h from the light-emitting source of the light-emitting diode element to the light extraction surface is R / h ≒ 10, and the light output and the light-emitting diameter of the light-emitting diode device have a built-in dome-shaped light emission. The light output and the light emission diameter specific to the diode element are configured to be substantially the same.

[Action]

As described above, the light-emitting diode device of the present invention has a dome-shaped light-emitting diode element having a desired optical property as a light source for autofocus such as a camera, that is, a dome-shaped light-emitting diode element having a desired light output and a light emission diameter. Although packaged in a resin package, the curvature R of the light extraction surface of the resin package and the distance h from the light emitting source of the dome-shaped light emitting diode element to the light extraction surface are R / h ≒ 10, and the light emitting diode device The characteristics of the light emitted from the light emitting device have substantially the same optical characteristics without impairing the optical characteristics of the built-in dome-shaped light emitting diode element, and desired characteristics can be obtained. Further, since the light emitting diode device of the present invention has a resin package structure, the production cost is lower than that of a can package product.

〔Example〕

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

FIG. 1 is a front view showing a light emitting diode device according to one embodiment of the present invention, FIG. 2 is a sectional view showing a fixed state of the light emitting diode element, and FIG. 3 is a positional relationship between the light emitting diode element and a submount. Exploded perspective view showing the fourth
FIG. 5 is a front view showing an assembled state of the light-emitting diode device, FIG. 5 is a cross-sectional view showing a mold state in the manufacture of the light-emitting diode device, and FIG. Curvature change,
FIG. 7 is a graph showing the correlation between the light output of the dome-shaped light emitting diode element and the light output fluctuation of the light emitting diode device by the resin package. FIG. 7 shows the curvature change of the light extraction surface with respect to the distance from the light source to the light extraction surface, and the dome shape. 6 is a graph showing a correlation between a light emitting diameter of a light emitting diode element and a light emitting diameter variation of a light emitting diode device using a resin package.

As shown in FIG. 1, a light emitting diode device 1 according to this embodiment has a resin package 2 made of a stepped cylindrical transparent resin having a thick bottom, and a protrusion 2 protruding from the lower end of the resin package 2. And a book lead 3.

The upper end of the resin package 2 is a light extraction surface 4 and has a curved surface having a curvature R which is the reciprocal of the radius of curvature. Further, in the resin package 2, one end face (upper end face) of the lead 3 is provided with an eutectic layer 5 made of gold and silicon as shown in an enlarged sectional view of FIG.
The submount 6 is fixed, and a dome-shaped light-emitting diode element (dome-shaped chip) 7 having a face-down structure is fixed on the submount 6. The distance h from the light emitting source (light emitting position) of the dome-shaped chip 7 to the light extraction surface 4 of the resin package 2 is 1.0 mm.

Here, the dome-shaped chip 7 will be briefly described.

As shown in FIGS. 2 and 3, the dome-shaped chip 7 has a hemispherical (dome-shaped) dome surface 10 on one surface, and in FIG.
11 has a cathode electrode 12 and an anode electrode 13. The cathode electrode 12 is located at the center of the main surface and is a point electrode having a diameter of about several tens to about 100 μm. Further, the anode electrode 13 is a cathode electrode 12 which is a point electrode.
Are concentrically surrounded by a horseshoe-shaped electrode.

Also, as shown in FIG.
The lower n ^{+ -type} layer 14 and the lower p ^{+ -type} layer 15 under the anode electrode 13 are electrically separated by a ring-shaped groove (mesa-etch groove). An n-type layer 16, a p-type layer 17, and a GaAlAs layer 18 are sequentially provided inside the n ^{+ -type} layer 14. The p-type layer 17 is in contact with the p ^{+ -type} layer 15, and the groove is provided deeply so as to divide the pn junction into a ring. Further, the groove is covered with a passivation film 19 in which a PSG film and a SiO ₂ film are stacked.

The dome-shaped chip 7 has a dome height of 200 μm and a dome radius of 200 μm. The light emission diameter defined by the groove is around 100 to 300 μm, for example, 200 μm.

On the other hand, the submount 6 attached to the tip of the lead 3 is made of silicon.
Since it is necessary to electrically insulate the dome-shaped chip 7 fixed thereon and the lead 3 for attaching the submount 6, an insulating layer 25 is provided on the upper surface.
As shown in FIG. 3, on the main surface (upper surface) of the submount 6, an anode wiring layer 26 and a cathode wiring layer 27 having a desired pattern are provided. The anode wiring layer 26 is the anode electrode 13 of the dome-shaped chip 7.
And a part thereof extends to one end of the submount 6 to form a bonding pad 28 for connecting a wire. The cathode wiring layer 27 has a pattern corresponding to the cathode electrode 12 of the dome-shaped chip 7, and a part thereof extends to the other end side of the submount 6 to form a bonding pad 29 for connecting a wire. doing. And the dome-shaped chip 7
Are positioned and fixed to the submount 6 by face-down bonding, as shown in FIG. The bonding pads 28 and 29 of the submount 6 and the corresponding leads 3 are electrically connected by a wire 30 made of a gold wire. The light emitting diode device 1 emits light 31 from the dome-shaped chip 7 enclosed in the resin package 2 by applying a predetermined voltage to the two leads 3.

Incidentally, this is is one of the features of the present invention, the optical characteristics of the light 31 emitted from the resin package 2, i.e., the optical output P _fM and emission diameter L _M is sealed in the resin package 2 _{So that} the light output P _fC and the light emission diameter L _{C of} the dome-shaped chip 7 itself are substantially the same.
The curvature R of the light extraction surface 4 of the resin package 2 and the distance h from the light emitting source of the dome-shaped chip 7 to the light extraction surface 4 of the resin package 2 are defined, and the correlation is R / h ≒ 10. Has become.

 The reason why R / h ≒ 10 of this correlation was set is as follows.

Chip light output of the dome-shaped tip 7 of the bare state that is not package P _fC, a chip light emitting diameter and L _C, the optical output of the light emitting diode device 1 which is molded with resin package P _fM, the light emitting diameter is L _M In the case, the light emitting diode device 1
That the light output P _fM and emission diameter L _M of the light 31 that is emitted is the same as the chip light output P _fC and chip light emitting diameter L _C of the dome-shaped tip 7 itself from, the following (1) and ( 2) Equation holds.

P _fM / P _fC = 1 (1) L _M / L _C = 1 (2) Therefore, let the curvature of the light extraction surface 4 of the resin package 2 be R, and emit light of the dome-shaped chip 7. Assuming that the distance from the light source to the light extraction surface 4 of the resin package 2 is h, the light emitting diode device 1 when R / h changes
Of the ratio of dependence of the tip optical output P _fC of the optical output P _fM and the dome-shaped tip 7, The ratio of the dependence of the chip light emitting diameter L _C of the light-emitting size L _M and the dome-shaped tip 7 of the light emitting diode device 1 I asked. FIG. 6 is a graph of the variation of the light output ratio with respect to the R / h variation, and FIG. 7 is a graph of the variation of the emission diameter ratio with respect to the R / h variation. From these graphs, by setting R / h ≒ 10, the above-mentioned equations (1) and (2), that is, P _fM / P _FC =
1 and L _M / L _C = 1, so that even if the resin package 2 covers the dome-shaped chip 7, the light 31 emitted from the resin package 2 will be the optical light emitted from the dome-shaped chip. Optical characteristics substantially the same as the characteristics can be obtained, and the same optical characteristics as those of the can package can be obtained in the resin package.

Next, a method for manufacturing such a light emitting diode device 1 will be described.

In manufacturing the light emitting diode device 1, first, a lead frame 40 as shown in FIG. 4 is prepared. The lead frame 40 is formed by punching a metal plate having a thickness of several mm with a press. The lead frame 40 has a structure in which a plurality of leads 3 protrude from one side of an elongated frame 41 in parallel at regular intervals. Further, a dam 42 which is parallel to the frame 41 and connects each lead 3 is provided. The unit lead frame is composed of two leads 3, as shown in FIG. Further, in the lead 3, the right lead 3 has a fixing portion 43 whose tip partially projects to the left. The submount 6 is fixed to the upper end of the fixing portion 43. The ends of the leads 3 are wide so that they do not come out of the resin package 2 after being molded, and the protrusions 44 and 45 are provided inside to prevent the leads 3 from coming off.
Is provided. The upper end of the fixing portion 43 is processed flat.

On the other hand, the dome-shaped chip 7 is positioned on the sub-mount 6 with respect to the anode wiring layer 26 and the cathode wiring layer 27 and fixed by face-down bonding.

Thus, the submount 6 to which the dome-shaped chip 7 is attached is fixed by the eutectic layer 5 on the fixing portion 43 of the lead frame 40. Next, the leads 3 are electrically connected to the bonding pads 28 and 29 of the anode wiring layer 26 and the cathode wiring layer 27 of the submount 6 by wires 30 made of Au.

Next, as shown in FIG. 5, the lead frame 40 is turned upside down so that the tip of the lead 3 to which the dome-shaped chip 7 is attached faces downward, and then the cavity 47 of the mold 46 of the cast mold is formed. Can be put in. The cavity 47 has a stepped circular hole having a large diameter at the top, and has a bottom surface formed with a curvature R, for example, a light extraction lens surface. In the cavity 47, a fixed amount of melted transparent resin 48 made of epoxy resin or the like is put. The lead frame 40 has a distance h from the light emitting source of the dome-shaped chip 7 to the bottom surface of the cavity 47,
For example, it is accurately lowered to a height of 1.0 mm. Thereafter, after the melted transparent resin 48 is cured, the lead frame 40 is pulled up. The melted transparent resin 48
Cures into a transparent resin package 2 and leads 3
It is pulled out of the mold 46 to cover the entire tip of the mold.

Next, unnecessary portions of the lead frame 40, that is, the frame 41
Then, the dam 42 is cut and removed, and the light emitting diode device 1 as shown in FIG. 1 is manufactured.

According to such an embodiment, the following effects can be obtained.

(1) The light-emitting diode device of the present invention has a structure in which a dome-shaped chip is sealed with a transparent resin package, but the curvature R of the light extraction surface of the resin package and the light-emitting source of the dome-shaped chip make the resin package. Since the relationship with the distance h to the light extraction surface is set to R / h ≒ 10, the characteristics of light emitted from the light emitting diode device are substantially the same as the optical characteristics of the dome-shaped chip itself. The effect is obtained.

(2) the above (1), light emitting diode device of the present invention, 200 of 20mW and chip light emitting diameter L _C of the optical output P _fM and emission diameter L _M is a dome-shaped chip having a built-chip optical output P _fC
μm, which is an effect that the light source can be sufficiently used as a light source for a camera or an autofocus for a VTR.

(3) Since the light emitting diode device of the present invention is manufactured by molding a dome-shaped chip with a transparent resin package, the effect that mass production is possible is obtained.

(4) Since the light emitting diode device of the present invention has a structure in which the dome-shaped chip is covered with a transparent resin package, the production cost is lower than that of a can package product which is difficult to process and assemble. Is obtained.

(5) According to (1) to (4), according to the present invention, it is possible to provide a resin package type light emitting diode device having optical characteristics substantially the same as the optical characteristics of a sealed dome-shaped chip at low cost. The synergistic effect of being able to do is obtained.

Although the invention made by the inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and various changes can be made without departing from the gist of the invention. Nor.

In the above description, the case where the invention made by the present inventor is mainly applied to a manufacturing technique of a light emitting diode device as a light source for an autofocus for a camera or a VTR, which is a background field of application, has been described. However, the present invention can be applied to a technique for manufacturing a light emitting diode device for optical communication.

〔The invention's effect〕

The effects obtained by the representative inventions among the inventions disclosed in the present application will be briefly described as follows.

The light emitting diode device of the present invention, in its manufacture,
Since the curvature R of the light extraction surface of the resin package and the distance h from the light emitting source of the dome-shaped chip to the light extraction surface of the resin package are designed to be R / h ≒ 10, the built-in dome Light can be emitted from the resin package without changing the inherent optical characteristics of the chip. In addition, this structure has a lower production cost than the conventional can package structure. Therefore, by incorporating a dome-shaped chip having a desired light output and emission diameter, a light-emitting diode device as a light source for a camera or an autofocus for a VTR can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a front view showing a light emitting diode device according to an embodiment of the present invention, FIG. 2 is a sectional view showing a fixed state of the light emitting diode element, and FIG. 3 is a positional relationship between the light emitting diode element and a submount. FIG. 4 is a front view showing an assembled state of the light-emitting diode device, FIG. 5 is a cross-sectional view showing a molded state in the manufacture of the light-emitting diode device, and FIG. Is a graph showing a correlation between a change in curvature of the light extraction surface with respect to the distance to the light source, and a change in the light output of the light emitting diode device by the resin package with respect to the light output of the dome-shaped light emitting diode element. The change in the curvature of the light extraction surface with respect to the distance and the light emitting diode with the resin package for the light emitting diameter of the dome-shaped light emitting diode element It is a graph showing a correlation between emission diameter change movement of the device. 1 ... light emitting diode device, 2 ... resin package,
3 ... lead, 4 ... light extraction surface, 5 ... eutectic layer, 6
...... Submount, 7 ... Light-emitting diode element (dome-shaped chip), 10 ... Dome surface, 11 ... Flat surface, 12 ... Cathode electrode, 13 ... Anode electrode, 14 ... n ^{+ -type} layer, 15 …
... p ^{+ -type} layer, 16 ... n-type layer, 17 ... p-type layer, 18 ... GaAlAs
Layer, 19 ... passivation film, 25 ... insulating layer, 26 ...
Anode wiring layer, 27 Cathode wiring layer, 28 Bonding pad, 29 Bonding pad, 30 Wire, 31 Light, 40 Lead frame, 41 Frame, 42
… Dam, 43… fixed part, 44, 45 …… projecting part to prevent falling off, 46
…… Mold type, 47 …… Cavity, 48 …… Melted transparent resin.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Satoru Kikuchi 15 Asahidai, Moroyama-cho, Iruma-gun, Saitama Hitachi East Semiconductor Company, Ltd. (56) References JP 50-148091 (JP, A) JP 63 −104489 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 33/00

Claims (1)

(57) [Claims] 1. A light-emitting diode element having a dome-shaped light-emitting surface is sealed with a transparent resin, and a light extraction surface of the transparent resin is formed in a curved surface. A light emitting diode device wherein a distance h from a light emitting source to the light extraction surface is set to satisfy a relationship of R / h ≒ 10.