JP2001267638A - Light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical medium or light emitting device which can obtain a desired brightness without using a plurality of diode chips such as LEDs. SOLUTION: The light emitting device is composed of a plurality of disc type LEDs 201, 202, 203, 204, and so on, and a housing type optical medium 116 for housing these LEDs 201, 202, 203, 204, and so on. The optical medium 116 has an incident surface, a recess for housing the LEDs 201, 202, 203, 204, and so on, an emitting surface for emitting a light, and a light conductor for connecting the incident surface to the emitting surface, and the recess is defined by the incident surface and a side wall formed continuously from the incident surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an application technique of a semiconductor light emitting device such as a light emitting diode (LED), and more particularly to a light emitter suitable for lighting equipment using the semiconductor light emitting device.

[0002]

2. Description of the Related Art Recently, a thin flashlight using a halogen lamp has been marketed, but the battery life of this type of flashlight is about 3 hours in continuous lighting, and the life of the halogen lamp itself is small. Also has the disadvantage of being short. On the other hand, liquid crystal display devices are frequently used in personal computers, word processors, small portable televisions, in-vehicle televisions, and the like. For the illumination (backlight) of such a liquid crystal display substrate, a fluorescent discharge tube (fluorescent lamp) is used. This backlight fluorescent lamp may be damaged when a portable TV or portable personal computer falls,
There is a problem that characteristics are easily deteriorated. In addition, when the device is used in a low temperature environment such as a cold winter region, the mercury vapor pressure in the tube is reduced, the luminous efficiency is reduced, and sufficient luminance cannot be obtained. Furthermore, stability and reliability for long-time operation are insufficient. The most important problem is that the power consumption is large. Taking a portable personal computer as an example, the power consumption of the liquid crystal display unit is overwhelmingly greater than the power consumed by the microprocessor and the memory. Therefore, when a fluorescent lamp is used as a backlight, it is difficult to operate a portable television or a portable personal computer with a battery for a long time. In addition, fluorescent light,
Since the light emission is pulsed in accordance with the frequency of the power supply, there is an individual difference, but the flickering causes a problem of eye fatigue. That is, in the case of a usage method close to direct illumination such as a backlight, there are problems such as eye fatigue caused by directly viewing the light from the fluorescent lamp for a long time, or an effect on the human body caused by eye fatigue.

A semiconductor light emitting device such as a light emitting diode (LED) converts electric energy directly into light energy, so that it is more efficient than a incandescent bulb such as a halogen lamp or a fluorescent lamp and does not generate heat when emitting light. Having.
In an incandescent sphere, electrical energy is temporarily converted to heat energy and the radiation accompanying the heat generation is used. The conversion efficiency is low in principle, and the conversion efficiency to light cannot exceed 1%. Absent. In a fluorescent lamp, electric energy is converted to discharge energy, and the conversion efficiency is similarly low. On the other hand, in the LED, the conversion efficiency can be about 20% or more, and the conversion efficiency of about 100 times or more as compared with the incandescent bulb or the fluorescent lamp can be easily achieved. Further, a semiconductor light emitting element such as an LED has a long life which can be considered to be semi-permanent, and has no problem of flickering like the light of a fluorescent lamp.

Although the LED has such excellent features, the application of the LED is limited to a very limited range such as a display lamp of a control panel of various devices and a display device such as an electric bulletin board. Few examples have been used in equipment. Recently, some LED application products for keyhole illumination are known, but they can only illuminate a small area. Apart from these special cases, in general,
LEDs are not used for lighting.

[0005] This is because despite the extremely high brightness of the LED, the light emission area of one LED is a small area of about 1 mm ² , so that a sufficient luminous flux as a lighting fixture cannot be obtained. I have.

As described above, when the conventional optical system is used, the illuminance on the surface to be illuminated does not reach a desired illuminance with the light emission of one LED. That is, the light flux per unit area on the surface illuminated by the light is insufficient.

[0007]

If a lighting device (lighting fixture) is assembled by simply arranging a large number of relatively expensive LEDs to obtain a desired illuminance, too many LEDs are required. Is unrealistic because it would be necessary, and as a result would be too expensive.

The present invention has been made to solve the above problems. Accordingly, an object of the present invention is to provide a storage-type optical medium that can obtain a desired illuminance by using a required minimum number of a plurality of diode chips.

Another object of the present invention is to efficiently extract the potential light energy of a plurality of diode chips without needlessly requiring a large number of diode chips.
It is to provide a small and bright luminous body.

Still another object of the present invention is to provide a luminous body which is inexpensive, has sufficient illuminance, and has long-term stability and reliability.

Still another object of the present invention is to provide a light-emitting body which consumes less power and has no flicker.

[0012]

SUMMARY OF THE INVENTION A feature of the present invention is that a light emitting device includes at least a plurality of diode chips for emitting light of a predetermined wavelength and a storage type optical medium for storing the plurality of diode chips almost completely. Being a body. The storage type optical medium has at least an incident surface, an exit surface for emitting light incident from the incident surface, and an optical transmission unit connecting the incident surface and the exit surface. Here, for example, the storage-type optical medium can be configured in a bullet-like shape having a cylindrical side surface and a hemispherical top (output surface). This storage type optical medium further has a concave portion for storing a plurality of diode chips. Here, the concave portion is constituted by the incident surface and a side wall portion formed continuously with the incident surface. That is, the bottom of the recess functions as the incident surface. For example, the concave portion can be formed in a bullet-like shape having a cylindrical side surface and a hemispherical bottom.

[0013] Specifically, the entrance surface and the exit surface may exist as end surfaces of the optical transmission unit. As the “transparent solid”, a transparent resin such as an acrylic resin, various glass materials such as quartz glass, soda-lime glass, borosilicate glass, and lead glass, and a transparent plastic material can be used. Alternatively, a crystalline material such as zinc oxide (ZnO), zinc sulfide (ZnS), or silicon carbide (SiC) may be used.

Here, the "diode chip" is LE
A semiconductor chip that functions as a semiconductor light emitting element such as D or a semiconductor laser corresponds to the semiconductor chip. Therefore, the semiconductor chip includes a predetermined semiconductor substrate, a multilayer semiconductor layer continuously and epitaxially grown thereon, an electrode layer, and the like.
Naturally, the “multi-layer semiconductor layer” includes a pn junction or a pin junction layer. Semiconductor light emitting devices
At the time of light emission, there is no remarkable heat generation effect, so even if `` a plurality of diode chips '' are stored inside the concave portion of the storage type optical medium constituting the light emitting body according to the feature of the present invention, There is no thermal effect on the retractable optical medium.

According to the illuminator according to the feature of the present invention, a plurality of diode chips can be used, and a desired illuminance can be easily obtained without requiring a large number of diode chips. This illuminance is an illuminance that cannot be achieved by a conventionally known optical system such as a lens. That is, it is possible to realize an illuminance that cannot be predicted by the conventional technical common sense. It should be noted that either one of the entrance surface and the exit surface may include a flat surface having an infinite radius of curvature or an infinity. This is because if one of the entrance surface and the exit surface has a predetermined (finite) radius of curvature that is not infinite, the convergence and divergence of light can be controlled. It should also be noted that the “predetermined divergence angle” may include 0 °, ie, parallel rays. Even if the divergence angle is 90 °, the light can be effectively condensed because the recess almost completely covers the plurality of diode chips optically. This is an operation that is impossible with a conventional optical system such as a lens. That is, the inner wall portion of the concave portion other than the incident surface (bottom portion) can also function as an effective light incident portion.

Specifically, it is preferable that each of the plurality of diode chips according to the features of the present invention be vertically stacked on the main surface of the chip. Here, the “main surface” is a plane of the parallel flat plate facing each other, and means excluding the side surface of the end. That is, the “main surface” is either the front surface or the back surface. Since the total output is a combination of a plurality of diode chips stacked vertically on the main surface, an extremely bright luminous body can be realized. Further, each of the plurality of diode chips may be molded into a disk shape. When the resin is molded in a bullet shape, a plurality of diode chips cannot be arranged close to each other because the diameter of the bullet is 3 mm to 6 mm. When molded in a disk shape, the occupied area is small, a plurality of diode chips are arranged close to each other, and it can be regarded as a point light source as a whole.

[0017]

Next, first to fourth embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimension, the ratio of the thickness of each layer, and the like are different from actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. In addition, it is needless to say that the drawings include portions having different dimensional relationships and ratios.

(First Embodiment) FIG. 1A is a schematic bird's-eye view showing a luminous body according to a first embodiment of the present invention, and FIG. 1B is a corresponding sectional view. It is. As shown in FIG. 1, the luminous body according to the first embodiment of the present invention comprises:
A plurality of diode chips 20 that emit light of a predetermined wavelength
, 1, 202, 203, 204,... And the plurality of diode chips 201, 202, 203, 204,.
And at least a storage type optical medium 116 that stores the storage medium almost completely. Specifically, the diode chips 201, 202, 203, 204,... Are respectively molded in disk-type packages (hereinafter, LED chips 201, 202 molded in these disk-type packages). , 203,204, ...
... are referred to as "disk-type LEDs 201, 202, 203, 2".
04, ... ". ). The storage optical medium 116 connects the incident surface, the exit surface for emitting the light incident from the incident surface, and the incident surface and the exit surface, and is adapted to the wavelength of the light emitted from the plurality of diode chips. And a light transmission section made of a transparent solid. As shown in FIG. 1, the storage-type optical medium 116 has a bullet-like shape including a cylindrical side surface and a hemispherical top. Further, this bullet-type storage optical medium 116 is a disk-type LED 201, 202, 2.
..,... Are provided at the bottom. The recess is composed of the incident surface and the side wall formed continuously with the incident surface. That is, the bottom of the concave portion functions as the incident surface. In FIG. 1, the recess has a bullet-like shape having a cylindrical side surface and a hemispherical bottom. The inner diameter of the cylinder constituting the side surface of the recess can be about 2 mm to 6.5 mm. On the other hand, the outer diameter of the cylinder forming the side surface of the storage optical medium 116 can be selected to be about 10 mm to 50 mm.

The difference between the outer diameter of the cylinder forming the side surface of the storage-type optical medium 116 and the inner diameter of the cylinder forming the side surface of the concave portion, that is, the wall thickness is substantially the same as the inner diameter of the cylinder forming the side surface of the concave portion.
Alternatively, it may be selected about 2 to 3 times, or more.

The plurality of disk-type LEDs 201, 2 shown in FIG.
, Are arranged on a film substrate 23 formed in a bullet shape. In FIG. 1, an incident surface serving as a bottom of a concave portion and a plurality of disc-type LEDs
Are shown as if there is a gap between the LEDs 201, 202, 203, 204,..., But a plurality of disk-type LEDs 201, 202, 203, 204,.
Is preferably arranged in close contact with the incident surface in order to obtain brighter light emission. For the film substrate 23, a flexible organic material can be used. For example, a thin polyethylene having a thickness of about 25 μm to 50 μm
A terephthalate (PET) thin film, a polyimide thin film, or the like can be used as the material of the film substrate 23.
As shown in FIGS. 2A and 2B, aluminum (Al) wirings 221, 222, 223, 224, 22 having a thickness of about 5 μm to 15 μm are formed on the surface of the film substrate 23.
.. Are patterned. Al wiring 22
1, 222, 223,... May be obtained by depositing an Al thin film on the entire surface of the film substrate 23 and then patterning the film by an etching method. Al wirings 221, 222, 223, ...
May be patterned using a screen printing method. By the patterning of the Al wirings 221, 222, 223,..., Openings where the film substrate 23 is exposed are periodically formed at predetermined positions on the surface of the film substrate 23. This opening is provided for the disc type LED 201,
202, 203,... Are rectangular windows for mounting. The disc-type LEDs 201, 202, 203,..., As shown in FIG.
LE inside each of 312, 313, 314, ...
D chips 301, 302, 303, 304,... Are arranged. Disk type LED 201, 202, 20
..., and Al wirings 221, 222, 223, ...
Are solders 211a, 211b, 212a, 212b,
213a, 213b,... Are connected to the first pin 21 and the second pin 22, respectively. As shown in FIG. 1B, a plurality of disk types L
The EDs 201, 202, 203, 204,... Are molded with the resin 24 inside the concave portion of the storage type optical medium 116.

In the first embodiment of the present invention, a plurality of disk type LEDs 201, 202, 203, 20
Since... Are almost completely confined in the concave portion of the storage type optical medium 116, all output light components emitted from the semiconductor chip including stray light components can effectively contribute to illumination. . That is, the inner wall portion of the concave portion other than the incident surface (bottom portion) can also function as an effective light incident portion. Further, a plurality of disk type LEDs 201, 202, 2
, And the concave portions of the storage-type optical medium 116, the light components reflected at the respective interfaces are multiple-reflected to become stray light components. In a conventionally known optical system such as a lens, these stray light components cannot be extracted so as to contribute to illumination. However, in the first embodiment of the present invention, these stray light components are also confined inside the concave portions, and may eventually be components that can contribute to illumination. As a result, regardless of the light extraction efficiency such as the shape of the resin mold (resin sealing body) 24, the reflection component between the optical systems, and the like, the potential quantum efficiency is substantially equal to the internal quantum efficiency. Disk type LED 201,
The light energy of 202, 203, 204,... Can be effectively extracted.

As described above, according to the illuminant according to the first embodiment of the present invention, a plurality of disc-type LEDs 20
It is possible to secure a light beam having a desired irradiation area as a light beam contributing to illumination and easily obtain a desired illuminance without requiring a large number of 1, 202, 203, 204,... I can do it. This illuminance is an illuminance that cannot be achieved by a conventionally known optical system such as a lens.

Incidentally, a plurality of disk-type LEDs 201, 202, and 202 used for the luminous body according to the first embodiment of the present invention.
As for 203, 204,..., LEDs of various colors (wavelengths) can be used. However, for lighting purposes such as flashlights, white LEDs are preferred because they are natural to the human eye. That is, this white LED is replaced with a plurality of disk-type LEDs 201, 202, 203, 20 shown in FIG.
This white plural disk type LE is used as
When a battery case and a battery (eg, AA battery) in the battery case are stored so that a predetermined voltage can be applied to D201, 202, 203, 204,... Electric lights (portable lighting equipment) are completed. What is necessary is just to have the structure which connects the electrode of several white disk-shaped LED201,202,203,204 ... to the anode and cathode of this battery, respectively. As a result, a flashlight (portable lighting device) with a simple structure and low manufacturing cost can be provided. This flashlight (portable lighting equipment)
Has excellent stability and reliability over a long period of time, and particularly has a long battery life because of low power consumption.

As the storage type optical medium 116 used for the luminous body according to the first embodiment of the present invention, various kinds of transparent resin such as acrylic resin, quartz glass, soda-lime glass, borosilicate glass, lead glass and the like can be used. Glass materials, transparent plastic materials and the like can be used. Alternatively, zinc oxide (Z
A crystalline material such as nO), zinc sulfide (ZnS), or silicon carbide (SiC) may be used. Among them, a transparent resin such as an acrylic resin, a transparent plastic material, or the like is a material suitable for mass production of the storage-type optical medium 116. That is, once a mold is formed and molded using this mold, the storage-type optical medium 116 can be easily mass-produced.

A plurality of disk type LEDs 201, 202,
.. May be connected in series as shown in FIG. 3 or may be connected in parallel as shown in FIG. In the case of serial connection, the current limiting circuit 12 is connected in series with the drive circuit 11, and a plurality of disk type LEDs 201 and 20 are connected.
It suffices to prevent excessive current from flowing through 2, 203, 204,... In case of parallel connection, each LE
D, that is, D ₁ , D ₂ ,..., D _n−1 , D _{n connected} in series with the current limiting resistors R ₁ , R ₂ ,..., R _n−1 , R _n . Then, the power supply voltage may be supplied via the drive circuit 11.

A sapphire substrate having a high insulating property is used as an epitaxial growth substrate of a gallium nitride (GaN) -based semiconductor material. Therefore, usually, both the anode electrode and the cathode electrode of the blue LED are taken out from the surface side of the epitaxial growth layer of the GaN-based semiconductor material.
Since this sapphire substrate is transparent to the wavelength of the blue LED, if a predetermined optical design such as using a transparent material at the bottom of the disk-type package on which the blue LED is mounted, light emission from the blue LED is It can also be taken out from the back side. In such a case, as shown in FIG. 5, it is preferable to arrange the rear mirror 26 on the rear surface of the storage type optical medium 116. In FIG. 5, the rear mirror 26 covers substantially the entire side surface of the storage optical medium 116, but may be formed so as to cover only a part of the side surface of the storage optical medium 116. May be omitted. The rear mirror 26 is formed by grinding a metal such as Al, brass, stainless steel, or the like into a shape shown in FIG. 5 using a lathe, a milling machine, or the like, or forming a metal by a press machine, and then polishing the surface thereof. Good. Furthermore, it is preferable to apply nickel (Ni) plating or gold (Au) plating on these surfaces because the reflectance is improved. As an inexpensive and simple method, a structure in which a metal thin film having high reflectivity such as an Al thin film is bonded may be used. Alternatively, the thermoplastic resin is processed into a shape shown in FIG. 5 by extrusion molding or injection molding,
A structure in which a metal thin film having a high reflectivity such as an Al foil or a dielectric multilayer film is deposited on the surface by vacuum evaporation or sputtering, or a structure in which a highly reflective polyester white film or the like is adhered may be used. Further, a structure in which a metal thin film or a dielectric multilayer film having a high reflectivity is directly deposited on the rear surface of the storage type optical medium 116 by vacuum evaporation or sputtering, a structure in which a metal thin film having a high reflectivity is formed by plating, or a composite film thereof But it doesn't matter.

A plurality of disk-type LEDs 201, 2 shown in FIG.
Are mounted on the film substrate 23 and connected to the first pins 21 and the second pins 22 by Al wiring, as in FIG. In FIG. 5, an incident surface serving as a bottom of a concave portion and a plurality of disc-type LEDs
Are shown as if there is a gap between the LEDs 201, 202, 203, 204,..., But a plurality of disk-type LEDs 201, 202, 203, 204,.
Is preferably arranged in close contact with the incident surface in order to obtain brighter light emission. The rear mirror 26 has a hole through which the first pin 21 and the second pin 22 pass,
The rear mirror 26 is designed so that the first pin 21 and the second pin 22 are not electrically short-circuited. If the bullet-shaped film substrate 23 is made of a transparent material, and the resin 24 filling the inside of the bullet-shaped film substrate 23 is also made of a transparent material, a plurality of disk-shaped LEDs 201, 202, 20
The light emission from 3, 204,... Also proceeds toward the back surface (rightward in FIG. 5). The plurality of disk-type LEDs 20
The light output from 1, 202, 203, 204,... To the right (backward) is reflected by the rear mirror 26, and a plurality of disk-type LEDs 201, 202, 203, 204,.
・ Output to the left from the surface of. As a result, the light output from the plurality of disk LEDs 201, 202, 203, 204,... In the right direction (back direction) is also combined with the light traveling in the surface direction (left direction in FIG. 5) and emitted. The surface gives a predetermined divergence angle. As described above, in the first embodiment of the present invention, the plurality of disk-type LEDs 201,
, 202, 203, 204,...
6 is almost completely confined in the recess of the storage type optical medium 1.
Since the rear mirror 26 is disposed on the rear surface of the light source 16, all of these stray light components can be output from the front surface which eventually becomes the light emitting surface. Therefore, all stray light components can effectively contribute to illumination. That is, focusing on the concave portion, the inner wall portion of the concave portion other than the incident surface also functions as an effective light incident portion, and the stray light component transmitted through the inner wall portion is reflected by the rear mirror 26.
And finally can be output from the light emitting surface side.
Also, a plurality of disk type LEDs 201, 202, 20
, And the concave portion of the storage-type optical medium 116, the components that are multiple-reflected at the respective interfaces are also confined in the concave portion, are reflected internally by the rear mirror 26, and emit light. To the front side. As a result, all of these multiple reflection components are finally output from the light emitting surface.

As described above, according to the illuminant according to the first embodiment of the present invention, the plurality of disc-type LEDs 20
It is possible to secure a light beam of a desired irradiation area as a light beam contributing to illumination without requiring an extremely large number of 1, 202, 203, 204,... Can be obtained. This illuminance is an illuminance that cannot be achieved by a conventionally known optical system such as a lens.

In FIG. 5, the front surface (outgoing surface) of the storage type optical medium 116 has a light emitting surface formed of a convex curved surface. However, FIG. 5 is an exemplification, and various shapes can be adopted for the exit surface depending on the purpose, and an optical medium having a light emitting surface having a concave exit surface may be used. When the concave emission surface is used as the light emission surface, light tends to be dispersed, so that uniformity suitable for various backlights (indirect illumination systems) can be obtained.

(Second Embodiment) In the luminous body according to the first embodiment of the present invention, a plurality of diode chips 20
1, 202, 203, 204,... Are respectively molded in a disk type package.
In the state of the bare chip, it may be arranged on the bullet-shaped film substrate 23. The bare chip is
This is preferable because it can be arranged more closely. That is, in the description of the light emitter according to the second embodiment of the present invention, as shown in FIG. 6 and FIG. 7, LEDs 201, 202, 203, 204,. A specific structure in the case of being arranged on a bullet-shaped film substrate 23 is shown. The structure of the storage type optical medium 116 may be the same as that of the luminous body according to the first embodiment of the present invention, and the description is omitted.

The LED chip is, as shown in FIG.
Via (Al₂O₃) Buffer layer on substrate 401
An n-type semiconductor layer 402 stacked via
It is composed of an active layer 403 and a p-type semiconductor layer 404.
You. Sapphire (Al₂O₃ ) The substrate 401 is an adhesive
With reference to 502, it is fixed to the film substrate 23. A
The node electrode 405 is substantially on the upper surface of the p-type semiconductor layer 404.
It can be formed over the entire surface. Anode electrode 405 and p
Of the ohmic contact characteristics with the semiconductor layer 404
For this, the anode electrode 405 and the p-type semiconductor layer 404
A contact layer made of a GaN-based p-type semiconductor
(Omitted) is preferably formed. Anode electrode 405
Is composed of an electrode layer transparent to light emission of the active layer 403.
Just do it. Specifically, tin (Sn) -doped oxide oxide
Indium (ITO) or tin oxide (SnO)₂) Like gold
Group oxides and the like are preferred. Or make the metal thin enough
It may be used as the transparent electrode layer 405. The other electrode
The cathode electrode 406, which is a layer, does not need to be particularly transparent.
No. Bonding pad part on part of anode electrode 405
Is provided, and a copper (Cu) foil is
Is connected. Casor
Similarly, the beam lead 51 made of copper foil is
1 is connected. Beam leads 511 and 512 are
Each of the conductive adhesive layers 501 causes the Al wirings 221 and
222.

As shown in FIG. 7, the LED chip may be mounted by flip chips using solder balls 411 and 412. In FIG. 7, the anode electrode 405
Is connected to the Al wiring 221 using the solder ball 411, and the cathode electrode 406 is connected to the A line using the solder ball 412.
l wiring 222. If the film substrate 23 is a transparent substrate, it is possible to emit light in two directions, the upper surface and the lower surface. The light emitted on the lower surface is similar to FIG.
The light may be reflected by the rear mirror 26 and returned toward the upper surface.

(Third Embodiment) The exit surface of the storage type optical medium 117 of the present invention may be a surface having a plurality of curvatures as shown in FIG. Others are basically the same as those in FIG. 5, and thus redundant description will be omitted. The exit surface of the storage type optical medium 117 shown in FIG. 8 may have a fisheye lens-like structure as shown in FIG. 9 or a concentric curved surface as shown in FIG.

Each of the lenses constituting the fisheye lens shown in FIG. 9 has a plurality of disk-shaped LEs mounted inside the concave portions.
.. Correspond to each of D201, 202, 203, 204,. More specifically, as shown in FIG. 11, a plurality of disk-type LEDs 201, 202, 2
High refractive index regions 24 corresponding to each of 03,.
9, 250, 251,... May be provided and led out to the corresponding output surfaces. The structure shown in FIG. 11 can be manufactured by fusing plastic optical fibers. As described above, the plurality of disk-type LEDs 201, 202, 20
Are preferably arranged in close contact with the incident surface serving as the bottom of the concave portion.

(Fourth Embodiment) A luminous body according to the first to third embodiments of the present invention comprises a plurality of diode chips 201, 202, 203, 204,. It is arranged in a quasi-planar (quasi-two-dimensional) manner on the surface of the formed film substrate 23. In this case, since there are actually a plurality of optical axes of output light corresponding to the respective diode chips, the plurality of diode chips 20
It may be difficult to regard 1, 202, 203, 204,... As point light sources. The luminous body according to the fourth embodiment of the present invention, as shown in FIG. 12, has a plurality of diode chips 61, 62, 63,... Stacked vertically on the main surface of the chip. Then, the optical axes of the respective output lights are matched. As described above, the “principal surface” is two planes of a parallel plate facing each other, and is a plane that is also parallel to the respective pn junction surfaces of the diode chips 201, 202, 203, 204,. . FIG. 13 is a diagram for explaining in detail a stacked state of a plurality of diode chips 61, 62, 63,... Although three layers are shown for simplicity, it is needless to say that four or more layers may be used. In FIG. 13, a first-layer diode chip (first-layer LED) 61 includes an n-type semiconductor layer 612, an active layer 613, and a p-type semiconductor layer 614 stacked on a sapphire substrate 611. Sapphire substrate 611
Are fixed to the support base 64 by an adhesive 602. The anode electrode 615 can be formed on almost the entire upper surface of the p-type semiconductor layer 614. Anode electrode 61
The central part of 5 may be formed of an electrode layer that is transparent to light emission of the active layer 613. The frame-shaped peripheral portion of the anode electrode 615 is made of a relatively thick gold (Au) thin film of about 0.5 μm to 2 μm for bonding. The cathode electrode 616 does not need to be particularly transparent. TA made of copper (Cu) foil around the frame-shaped peripheral portion of the anode electrode 615
The B lead (beam lead) 617 is connected. Similarly, a TAB lead (beam lead) 618 made of copper foil is connected to the cathode electrode 616. The second-layer diode chip (second-layer LED) 62 includes an n-type semiconductor layer 622, an active layer 623, and a p-type semiconductor layer 624 stacked on a sapphire substrate 621. The sapphire substrate 621 is fixed on the diode chip 61 of the first layer by a transparent adhesive 605. The anode electrode 625 can be formed on almost the entire upper surface of the p-type semiconductor layer 624. The central portion of the anode electrode 625 may be formed of an electrode layer that is transparent to light emission of the active layer 623. The frame-shaped peripheral portion of the anode electrode 625 is made of a relatively thick gold (Au) thin film of about 0.5 μm to 2 μm for bonding. Cathode electrode 62
6 need not be particularly transparent. A TAB lead (beam lead) 627 made of copper (Cu) foil is connected to a frame-shaped peripheral portion of the anode electrode 625. Similarly, a TAB lead (beam lead) 628 made of copper foil is connected to the cathode electrode 626. Similarly, the third-layer diode chip (third-layer LED) 63 includes an n-type semiconductor layer 632 and an active layer 6 stacked on a sapphire substrate 631.
33 and a p-type semiconductor layer 634. The sapphire substrate 631 is fixed on the diode chip 62 of the second layer by a transparent adhesive 606. The anode electrode 635 can be formed on almost the entire upper surface of the p-type semiconductor layer 634. The central portion of the anode electrode 635 may be formed of an electrode layer that is transparent to light emission of the active layer 633. The frame-shaped peripheral portion of the anode electrode 635 is made of a relatively thick gold (Au) thin film of about 0.5 μm to 2 μm for bonding. Cathode electrode 63
6 need not be particularly transparent. A TAB lead (beam lead) 637 made of copper (Cu) foil is connected to a frame-shaped peripheral portion of the anode electrode 635. Similarly, a TAB lead (beam lead) 638 made of copper foil is connected to the cathode electrode 636. TAB leads (beam leads) 617, 627, 637, 618, 628,
638 and bonding pads 615, 625, 635,
The connection with 616, 626, and 636 may be performed by a method used in normal TAB bonding such as thermocompression bonding, ultrasonic bonding, gold (Au) bump, and solder. Also, TAB lead (beam lead) 617,
The terminals 627 and 637 are connected to the terminal 603 by a conductive adhesive or solder. TAB leads (beam leads) 618, 628, and 638 are connected to the terminals 604 by a conductive adhesive, solder, or the like. The plurality of diode chips 61, 62, 63 are molded with a resin sealing body 608.

As shown in FIG. 12, the terminal 603 is connected to the second
And the terminal 604 is connected to the first pin 21. The terminal 603 and the terminal 604 are drawn out through a through hole provided in the rear mirror 26 via the reinforcing member 65. If a transparent material is also used for the resin 24 filled in the concave portion of the storage type optical medium 116, the light emission from the plurality of diode chips 61, 62, and 63 will be directed toward the rear surface (FIG. 12).
At right). Light output from the plurality of diode chips 61, 62, 63 in the right direction (backward direction) is reflected by the rear mirror 26 and the plurality of diode chips 6
Output is made to the left from the surfaces of 1, 62 and 63. After all,
Light output in the right direction (back direction) of the plurality of diode chips 61, 62, and 63 is also combined with light traveling in the surface direction (left direction in FIG. 12), and a predetermined divergence angle is given by the emission surface. As described above, in the fourth embodiment of the present invention, the plurality of diode chips 61, 62, 63
Is almost completely confined in the recess of the storage type optical medium 116, and a rear mirror 26 is arranged on the rear surface of the storage type optical medium 116. For this reason, all light, including light that can be a stray light component,
Output is possible along substantially the same optical axis. Therefore, all the light-emitting components emitted in various directions of the diode chips 61, 62, and 63 are effectively collimated, and can contribute to illumination.

A plurality of diode chips 61, 62, 6
... need not necessarily be the same LED chip. That is, the plurality of diode chips 61, 62, 6
As for 3,..., Various types and structures can be used. For example, a plurality of diode chips 61, 62, 6
If three LED chips of red (R), green (G), and blue (B) are vertically stacked, white output light can be output as a whole. In the case of three LED chips of red (R), green (G) and blue (B), the LE of red (R)
As D chip Al _x Ga _{1 -x} As is used as a green (G) LED chip for Al _x Ga _y In.
It is possible to use the _In x _{Ga 1-x} N and ZnSe as LED chips _1-x-y P a and GaP Oyobi blue (B). In this case, Al _x Ga _1-x As, Al
_{x Ga y In 1-x-} y P, GaP , etc. is not necessary to use a sapphire substrate.

Alternatively, compound semiconductor mixed crystals such as ternary, quaternary, quinary,...
2, 63,..., And the respective compositions may be changed. For example _{In x Al y Ga 1-x} -y N formed of a plurality of diode chips 61, 62, 63, ....
May be selected and the composition of each may be changed to output light in the green (G) to blue (B) spectral bands.

Further, there is a disadvantage that the optical axis is dispersed.
As shown in FIG. 4, a plurality of diode chips 61a, 62a, 63a stacked vertically, a plurality of diode chips 61b, 62b, 63b stacked vertically, a plurality of diode chips 61c, 62c stacked vertically.
63c may be arranged on the bullet-shaped support base 67 in a quasi-planar manner. In this case, 3 × 3 = 9 times the brightness can be obtained. Diode chips stacked in three layers
By arranging five stacks in a quasi-plane, it is possible to obtain 3 × 5 = 15 times the brightness. In FIG. 14, a support 67 made of a transparent resin molded into a bullet shape is used, but a film substrate as in the first embodiment may be used. In addition, a support base 64 having a flat mounting surface as shown in FIG. 12 may be used. By arranging a plurality of diode chip stacks close to each other on a support 64 having a flat mounting surface as shown in FIG. 12, it is possible to obtain a strong output in a state almost similar to a point light source.

(Other Embodiments) As described above, the present invention has been described with reference to the first to fourth embodiments.
The discussion and drawings that form part of this disclosure should not be understood as limiting the invention. From this disclosure, various alternative embodiments, examples, and operation techniques will be apparent to those skilled in the art.

For example, a lighting fixture or the like may be constructed by arranging a plurality of luminous bodies according to the first to fourth embodiments.
In this case, three colors of red, green and yellow two-dimensionally arranged in a disk shape may be prepared and used for a traffic light.

A fluorescent substance is mixed with a transparent resin or a glass material used for the storage type optical medium of the present invention, or a layer of a fluorescent substance is formed on the surface of the storage type optical medium, and these fluorescent substances are irradiated with light from a light emitting diode. It is also possible to excite and obtain a desired fluorescent color.

If high illuminance is not required, only one LED chip molded in a disk-shaped package or only one LED chip in a bare chip state may be used.
It may be stored in the recess of the storage type optical medium of the present invention. Even with only one LED chip, a sufficiently bright illuminance can be obtained as compared with the related art.

As described above, the present invention naturally includes various embodiments and the like not described herein. Therefore, the technical scope of the present invention is determined only by the invention specifying matters according to the claims that are appropriate from the above description.

[0045]

According to the present invention, it is possible to provide a luminous body which can use a plurality of diode chips and can obtain a desired illuminance without requiring a large number of diode chips. .

Further, according to the present invention, the potential light energy of the plurality of diode chips can be efficiently extracted, and an illuminance which cannot be achieved by a conventionally known optical system such as a lens can be realized.

Further, according to the present invention, it is possible to provide a light-emitting body which consumes less power and has no flicker.

[Brief description of the drawings]

FIG. 1A is a schematic bird's-eye view showing a luminous body according to a first embodiment of the present invention, and FIG. 1B is a corresponding sectional view.

FIG. 2 (a) shows a plurality of disk-type LEDs of FIG. 1;
FIG. 2B is a cross-sectional view for explaining details of the case where is disposed on a film substrate formed in a bullet shape, and FIG. 2B is a corresponding plan view.

FIG. 3 is a circuit diagram when a plurality of disk-type LEDs are connected in series.

FIG. 4 is a circuit diagram when a plurality of disk-type LEDs are connected in parallel.

FIG. 5 is a schematic cross-sectional view illustrating a light-emitting body according to a modification of the first embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view showing a specific structure in a case where LEDs in a bare chip state are arranged on a bullet-shaped film substrate in the light-emitting body according to the second embodiment of the present invention. It is.

FIG. 7 is a schematic diagram showing another specific structure in the case where LEDs in a bare chip state are arranged on a bullet-shaped film substrate in the light-emitting body according to the second embodiment of the present invention. It is sectional drawing.

FIG. 8 is a schematic sectional view showing a luminous body according to a third embodiment of the present invention.

FIG. 9 is a schematic bird's-eye view showing a luminous body according to a third embodiment of the present invention.

FIG. 10 is a schematic bird's-eye view showing a light-emitting body according to a modification (first modification) of the third embodiment of the present invention.

FIG. 11 is a schematic cross-sectional view showing a light-emitting body according to a modification (second modification) of the third embodiment of the present invention.

FIG. 12 is a schematic sectional view showing a luminous body according to a fourth embodiment of the present invention.

FIG. 13 is a schematic cross-sectional view for explaining in detail a stacked state of a plurality of diode chips of FIG.

FIG. 14 is a schematic cross-sectional view showing a light emitting body according to a modification of the fourth embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 11 drive circuit 12 current limiting circuit 21 first pin 22 second pin 23 film substrate 24, 25 resin 26 rear mirror 61, 62, 63, 61a, 62a, 63a, 63b, 61b
62b, 63b, 61c, 62c, 63c Diode chip 64, 67 Support 65 Reinforcement 116, 117 Storage type optical medium 201, 202, 203, 204 Disk type LED 221, 222, 223, 224, 225 Aluminum (Al) wiring 211a, 211b, 212a, 212b, 213a,
213b, 214a, 214b Solder 301, 302, 303, 304 LED chip 311, 312, 313, 314 Ceramic package 401, 611, 621, 631 Sapphire (Al
₂ O ₃ ) substrate 402, 612, 622, 632 n-type semiconductor layer 403, 613, 623, 633 active layer 404, 614, 624, 634 p-type semiconductor layer 405, 615, 625, 635 anode electrode 406, 646, 626 , 636 Cathode electrode 411, 412 Solder ball 501 Adhesive layer 502, 602 Adhesive 511, 512 Beam lead 603, 604 Terminal 605, 606 Transparent adhesive 608 Resin sealing body 617, 627, 637, 618, 628, 638 T
AB lead

Claims (3)

[Claims] 1. An entrance surface, an exit surface, and an optical transmission unit connecting the entrance surface and the exit surface, and further comprising: the entrance surface; and a side wall portion formed continuously with the entrance surface. A light-emitting body, comprising: a storage optical medium having a concave portion formed of: and a plurality of diode chips stored in the concave portion. 2. The light emitting device according to claim 1, wherein each of the plurality of diode chips is vertically stacked on a main surface of the chip. 3. The luminous body according to claim 1, wherein each of the plurality of diode chips is molded in a disk shape.