JP2002335019A - Light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting device which can be repaired and driven stably, regarding a light emitting device which is capable of large current high luminance light emission. SOLUTION: This light emitting device is provided with a substrate (102) having through holes, retaining members (105) fitted to the through holes, and light emitting elements (101) arranged on the retaining members.

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 capable of emitting large current and high luminance, and more particularly to providing a light emitting device which can be repaired and can be driven stably.

[0002]

2. Description of the Related Art Today, as light emitting devices, in addition to light emitting diodes capable of emitting RGB (red, green, blue) light with high luminance, light emitting diodes capable of emitting ultraviolet light, white light (for example,
Light-emitting diodes and laser diodes capable of emitting light (including white as defined in JIS8110) have been developed. These semiconductor light emitting devices have excellent characteristics such as high luminance, low power consumption and long life. For this reason, it is beginning to be used not only for various displays outdoors and indoors, for traffic signals such as traffic and railroads, for various indicators and signs, and for backlights of liquid crystal devices, but also as lighting itself.

[0003] Such a light emitting device has a plurality of S on a substrate in which a copper foil pattern is formed on the surface of a glass epoxy resin.
An MD type light emitting diode and a shell type light emitting diode are arranged and electrically connected to form a unit. When used as lighting or a traffic light, each light emitting diode is connected in series and / or in parallel and connected to a power source. Each light emitting diode constituting the unit emits light by supplying current from a power supply. When used as a traffic light or lighting, a lens is provided on a light emitting diode to improve or scatter directional characteristics in a specific area. Normally, as more current flows through the LED, which is a semiconductor light emitting element, the emission luminance increases relatively linearly up to a certain current. On the other hand, the luminous efficiency decreases in inverse proportion to the temperature rise of the LED. Further, the spectrum of light emitted from the light-emitting element may shift with an increase in temperature.

In order to solve such a problem and construct a brighter light emitting device, a configuration shown in FIG. 4 can be considered.
In FIG. 4, a large number of LED chips (401) are closely arranged via an insulating layer (405) and a conductive pattern (403) on an aluminum or ceramic substrate (402) having relatively high thermal conductivity as compared with resin. It has been implemented. With such a configuration,
An LED power module or the like having stable characteristics while allowing a large current to flow through each light emitting element while increasing the amount of light can be provided.

[0005] However, since the high heat conductive substrate has a function of mounting the semiconductor light emitting element, electric conduction, and heat conduction, the overall efficiency is low. Requires higher luminance. Further, if the LED chip (401) is die-bonded on aluminum or ceramic, the module itself may be damaged during repair such as removal of the LED chip. Furthermore, since it has good thermal conductivity, it is difficult to remove only a defective LED chip after mounting, and in the process, even a non-defective LED chip may be thermally and mechanically damaged. In particular, when removing and re-mounting individual LED chips, when heated, not only the repaired part due to the high thermal conductive substrate (402) but also the other good parts adjacent to it are heated, and all the modules are destroyed. It is possible that

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a light emitting device capable of stably emitting light with high luminance and a light emitting device in which light emitting elements can be relatively easily detached individually and repaired easily. Things.

[0007]

SUMMARY OF THE INVENTION The present invention is a light emitting device including a substrate having a through hole, a support member that fits into the through hole, and a light emitting element disposed on the support member. Thus, the light emitting device can be configured relatively easily. Further, since the support is fitted into the through-hole, the light emitting device can be configured to be extremely thin.

A light emitting device according to a second aspect of the present invention is a light emitting device in which the support member has a higher thermal conductivity than a substrate having a through hole. This facilitates thermal function separation between the light emitting element and the substrate serving as the housing. Therefore, heat from the light emitting element generated by flowing a large current can be efficiently released from the support member to the outside.

According to a third aspect of the present invention, in the light emitting device, the support member is detachable from the through hole of the substrate. Thus, when a defect occurs in the light emitting element, only the defective light emitting element can be replaced without damaging the substrate or another semiconductor element mounted at the same time.

The light emitting device according to claim 4 of the present invention is
This is a light emitting device having a reflector structure on a support member.
Thus, the light from the light emitting element can be efficiently extracted to the outside, and the support member itself inserted into the through hole has a reflector structure. Therefore, the thickness of the entire light emitting device can be extremely reduced while having the reflector structure.

[0011] The light emitting device according to claim 5 of the present invention comprises:
This is a light emitting device in which a support member is plated. By separating the heat conduction of the support member and the reflection of light from the light-emitting element in function, their characteristics can be improved. In addition, when viewed from the surface of the light emitting device, only the support member appears to be plated separately from the surface of the substrate itself, so that the plated portion can be relatively easily formed small in accordance with the size of the cavity. Further, even if it is placed at the time of repair, it is only necessary to newly replace the support member, so that the plated portion is not damaged as compared with a configuration in which plating is formed on the substrate in advance.

A light emitting device according to a sixth aspect of the present invention is a light emitting device in which a substrate is made of a glass epoxy resin having a conductive pattern formed on a surface. Thereby, the support member can be electrically separated from the light emitting element, so that conduction and heat conduction can be functionally separated.

[0013] In the light emitting device according to claim 7 of the present invention, the bottom of the support member is larger than the surface on which the light emitting element is arranged.
Due to the shape of the convex support member such as a thumbtack, heat dissipation efficiency can be improved and reliability can be improved, and mounting and repair can be performed relatively easily, and mass productivity can be increased. Also, the bottom part can function as a stopper at the time of fitting.

[0014] In the light emitting device according to claim 8 of the present invention, the support member has a heat releasing means. Since the supporting member is formed to have a structure having heat releasing means such as a heat sink, the light emitting element directly disposed on the supporting member is less likely to be deteriorated by heat.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of various experiments, the present inventor has determined that the relationship between a support on which a light-emitting element is mounted and a casing of a specific shape holding the support improves light-emitting characteristics and mountability. And found the invention of the present application.

That is, according to the present invention, the substrate for holding and mounting the light emitting element is separated into a substrate having a through hole and a support on which the light emitting element is detachably mounted.
Even when it is necessary to replace the light emitting element after mounting due to a defect of the light emitting element, it is possible to replace the defective light emitting element without adversely affecting other light emitting elements by an extremely simple configuration that only removes the support from the substrate instead of the light emitting element it can. An embodiment of the present invention is shown in FIGS.

A plurality of through-holes (10) are formed on a stainless steel substrate (102) having a copper foil pattern (103) constituting a lead electrode previously formed on the surface thereof via an insulating film (106) by using a drill or the like.
8) is formed. Next, a copper plate having a flat plate-like projection is used as a support (105) (step of FIG. 3A).
A plurality of projections are provided so as to fit into the through holes of the substrate, and a cavity is formed at the tip of the projection so that the LED chip (101) is arranged. A flat plate with a projection serving as a support is fitted into the through hole (108) of the substrate (FIG. 3).
(Step (B)). Next, to form each support, the flat plate with the protrusion is separated (310) by etching. As a result, the support (105) separated into the plurality of through holes is brought into a state where it is fitted. In the next step, pn on sapphire substrate
An LED chip (101) on which a gallium nitride-based compound semiconductor layer having a junction is formed is die-bonded with an epoxy resin into a cavity forming a support body that is laid on a substrate.

In this case, since the semiconductor is formed on the insulating substrate, a pair of electrodes for extracting a pair of electrodes from the same surface side is used.
D configuration. After curing the die bond resin, LE
Copper pattern provided on each electrode of D chip and the surface of substrate
(103) is suitably wire-bonded with a gold wire (104). In this way, an LED power module can be configured (the step of FIG. 3C). Although the case where a plurality of supports are formed has been described, it is needless to say that the light-emitting diode can be formed with only one support. Also, on the LED power module,
A light-transmitting resin may be provided, or a lens may be provided. When a lens is provided, a resin such as silicon may be interposed or a gas may be sealed. Such a lens may be formed in advance, may be formed using a curable resin, and may be formed using a mold or the like. In addition, these lenses may be provided with a fluorescent substance which is excited by the emission wavelength of the light emitting diode and emits light of a longer wavelength. Thus, not only light from a light emitting element but also light from a fluorescent substance can be used, so that a light emitting device having light of various wavelengths can be provided.

Next, an example of a repair process will be described. A light emission test can be performed by applying a current to the lead electrode of the light emitting device formed as described above (FIG. 3D).
Process). Light emitting element (301) with defective light emission test
Specifies the position of the die-bonded support member with an image recognition device. By pushing down only the support member from the emission observation surface with a pin from the substrate, the support member to which the defective light emitting element is die-bonded can be removed. Subsequently, after mechanically removing the wire that electrically connects the defective light emitting element and the conductive pattern on the substrate, the supporting member with the light emitting element (305) is inserted again into the through hole ( FIG. 3E). Repair can be easily performed with a relatively simple configuration by wire-bonding the light emitting element (step of FIG. 3F). Hereinafter, each configuration of the present invention will be described in detail.

(Light Emitting Elements 101 and 201) As the light emitting element used in the present invention, various semiconductor light emitting elements can be used. Specific semiconductor light emitting devices include sapphire,
A structure in which an n-type nitride semiconductor and a p-type nitride semiconductor are stacked on a substrate of SiC, spinel, GaN, or the like using MOCVD or the like can be suitably used. Ga
N, GaAlN, InGaN, AlN, InN, InG
In addition to nitride semiconductors such as aAlN and GaInBN, InGaP, GaP, GaAs, GaAlAs, Al
A light emitting element using various semiconductors such as P, AlAs, ZnS, ZnSe, and SiC for a light emitting layer can be suitably used. When a conductive material is used for the substrate, the support member may be die-bonded with an Ag paste, solder, or the like so as to be electrically connected, or an insulating layer may be interposed therebetween.

(Substrates 102 and 202) The substrates used in the present invention have through holes and can be fitted with support members. The substrate itself can hold the support member, and may be fixed by fitting or fixed by protrusions. Various types can be used, such as those fixed with a screw type, those fixed with a metal or brazing material that melts at a temperature at which the light emitting element and the like are not destroyed. Since the substrate of the present invention uses the through hole for fitting the support member, it can be manufactured relatively easily, and can be separated in function from the support member in accordance with the purpose such as heat dissipation and mechanical strength. Further, the through hole provided in the substrate can be formed by a drill or can be provided by a laser. Further, it can also be formed by punching. The shape of the through hole can be variously selected from a circle, an ellipse, a quadrangle, a triangle, and the like, depending on the support member that matches the directional characteristics of the light emitting element. As a specific material of such a substrate, it is possible to use various materials such as glass epoxy resin, copper, aluminum, various alloys, and ceramics on which a conductive pattern such as a copper foil constituting a lead electrode is formed on the surface in advance. it can. When a metal is used as a substrate having a lead electrode on its surface, an insulating film such as SiO ₂ or SiNx is formed to electrically insulate, and then a thin film pattern of copper, gold, silver, or an alloy containing these metals, CV such as laminated film containing metal
D and those formed by sputtering can be suitably used. (Supporting members 105 and 205) The supporting member of the present invention is a member on which a light emitting element is arranged, and can be fitted into a through hole of a substrate. A cavity may be provided on the surface of the support member on which the light emitting element is disposed to reflect light from the light emitting element efficiently, and may have a reflector structure. Further, plating with a metal or alloy having high reflectivity can also be performed. Gold, silver, copper, nickel, and various alloys can be suitably used as such a metal. As a material of the supporting member itself, Au, Cu, Al, an alloy thereof, or the like can be suitably used as a material having high thermal conductivity in order to efficiently extract heat from the light emitting element to the outside. In particular, copper and aluminum can be suitably used because of ease of processing and the like.

In order to form a light emitting diode with good mass productivity, a light emitting diode having a plurality of projections on which light emitting elements are arranged in a flat plate shape can be used. After being fitted to the substrate, they can be separated as respective light emitting element support members, or can be used as they are. In the case of separation, the protrusions should be 1
They may be separated one by one, or they may be separated into two or more parts. Further, the supporting and supporting member can be used as a part of the lead electrode. Note that a protrusion (107) of the support member may be provided in order to improve the positioning between the support member and the substrate and prevent the support member from slipping off, and to prevent mass removal. It is preferable to provide a concave portion corresponding to the protrusion on the substrate.

In order to efficiently release the heat generated when the light emitting element is driven, the support may have a heat releasing means. As the heat releasing means, a method for improving heat radiation by increasing the surface area such as making a flat plate larger or providing irregularities on the back surface (the surface opposite to the protrusion), or a means for transferring heat such as a heat pipe is used. There is a method of disposing the heat and moving the heat to a remote position.

As a device having a mechanism for increasing the surface area by unevenness, there is a heat sink. The heat sink has a mechanism of absorbing heat and then releasing the heat. Specifically, as shown in FIG. 5, the heat sink has a shape in which a convex portion is provided on the back surface of the support. With such a structure, the surface area can be increased, so that heat generated from the light-emitting element and stored in the support can be efficiently released to the outside. Increasing the number of protrusions or increasing the number of protrusions increases the surface area, but also increases the size of the support itself, so that a preferable shape, material, or the like can be selected according to heat released from the light-emitting element.

The heat pipe efficiently conducts heat, and can emit heat by efficiently conducting heat to a position away from the light emitting element. Such a heat pipe can be formed by evacuating the inside of a metal pipe having a capillary structure on the inner wall of the pipe and sealing a small amount of water, CFC substitute, or the like as a working fluid. Specifically, one end of the heat pipe is thermally connected to a support on which the light emitting element is disposed, and the other end is disposed at a position away from the support. The heat released from the light emitting element reaches one end of the heat pipe through the support, and the working fluid in the heated portion evaporates. The working fluid that has become a vapor flow moves to the other end where the temperature is lower than the heated one end where the light emitting element is disposed. When the vapor flow comes into contact with the tube wall of the low-temperature part and is cooled and condensed, the vapor flow returns to the support thermally in contact with the light emitting element by capillary action or gravity, so that heat can be continuously transported repeatedly. Thus, heat generated by the light emitting element can be efficiently conducted. If the other end of the heat pipe is away from one end connected to the support, it functions as a low-temperature portion without providing anything, but in order to transfer and release heat more effectively, a cooler or the above May be provided. In this way, by providing the heat transfer means in addition to the heat release means on the support on which the light emitting element is disposed, the heat release means can be disposed at a position away from the substrate, and therefore, depending on the form of the light emitting device. Can be used in various ways.

(Fluorescent substance) The fluorescent substance that can be used in the present invention is an inorganic fluorescent substance that is excited by an emission wavelength emitted from a light emitting element and emits visible light having a longer wavelength than that light. Phosphors may be used, and emission colors of all visible light from purple to red can be applied. Specifically, examples of the inorganic phosphor include a silicate-based phosphor, a phosphate-based phosphor, an aluminate-based phosphor, a rare-earth-based phosphor, an rare-earth-based phosphor, and a zinc-sulfide-based phosphor. . Specifically, in the case of a green light-emitting phosphor, Y ₂ Si
O ₅ : Ce, Tb, MgAl ₁₁ O ₁₉ : Ce, Tb,
BaMg ₂ Al ₁₆ O ₂₇ : Mn, (Zn, Cd) S:
Ag, ZnS: Au, Cu, Al, ZnS: Cu, A
l, SrAl ₂ O ₄ : Eu, blue light emitting phosphor (S
rCaBa) ₅ (PO ₄ ) ₃ Cl: Eu, (BaCa)
₅ (PO ₄ ) ₃ Cl: Eu, BaMg ₂ Al
₁₆ O ₂₇ : Eu, Sr ₅ (PO ₄ ) ₃ Cl: Eu, S
r ₂ P ₂ O ₇ : Eu, ZnS: Ag, Al, ZnS: A
g, Al (pigmented), ZnS: AgCl,
ZnS: AgCl (pigmented), and Y ₂ O ₂ S: Eu and Y ₂ O ₂ S: Eu (pi
_{gmented), Y 2 O 3:} Eu, 3.5MgO ·
0.5MgF ₂ · GeO ₂ : Mn, Y (PV) O ₄ : E
_{u, 5MgO · 3Li 2 O ·} Sb 2 O 5: Mn, Mg 2
TiO ₄ : Mn and the like. As a material having relatively high luminous efficiency, a green luminescent phosphor is SrAl ₂ O ₄ :
Eu and Sr ₅ (PO ₄ ) ₃ Cl for the blue light emitting phosphor:
Eu and a red light emitting phosphor include Y ₂ O ₂ S: Eu.

Hereinafter, specific embodiments of the present invention will be described in detail, but it is needless to say that the present invention is not limited thereto.

[0028]

(Embodiment 1) The present invention will be described with reference to FIG. The copper foil pattern (20
3) A through hole is formed in the glass epoxy resin (202) formed on the surface by using a drill, etching, laser or the like. Next, the metal plate on which the plate-like projections are formed is
05). LED chip (201) at the tip of the protrusion
Are arranged to form a cavity so that light from the LED chip can be effectively extracted to the outside. Support (205)
The flat plate having the projections is fitted into the through hole of the substrate (202). The support member is fitted into the through hole of the substrate.
In the next step, an LED chip (20) having a gallium nitride-based compound semiconductor layer having a pn junction formed on a sapphire substrate
1) is die-bonded with an epoxy resin into the cavity constituting the support (205).

In this case, since the semiconductor is formed on the insulating substrate of the LED chip (201), a pair of electrodes are taken out from the same surface side. After curing the die bond resin, each electrode of the LED chip (201) and the copper pattern (203) provided on the surface of the substrate (202) are preferably wire-bonded with a gold wire (204). Next, the LED chip (2
01) A lens formed to efficiently collect light from
(209) is provided in close contact with the substrate (202). An inert gas, silicon resin (210), or the like is sealed inside. With the light-emitting device having this configuration, the light-emitting device can be relatively easily repaired. Note that an LED chip having a pn junction formed on an insulating layer is used. However, when the support itself is used as a part of a lead electrode or when an insulating spacer is formed, a pair of electrodes is interposed via a semiconductor. Needless to say, it is possible to use an LED chip provided with.

(Example 2) As the support, a support (511) having a shape having irregularities on the back surface (the surface opposite to the surface on which the protrusions are formed) as shown in FIG. 6 is used. A plurality of protrusions are formed on the support, and irregularities are formed on a surface (back surface) opposite to the protrusions. Further, in the present embodiment, a continuous lens formed in a lens shape so that light can be collected at a position facing each protrusion as a lens is used, but a lens may be provided for each light emitting element. There is no problem at all. Furthermore, as shown in the figure,
A fluorescent substance is provided inside the lens, that is, on the side facing the light emitting element. The fluorescent substance can be provided inside the lens by being mixed with a resin or the like, applied, and cured. The fluorescent substance may be mixed in the lens material. A light emitting device of the present invention is obtained in the same manner as in Example 1 except that such a support and a lens are used.

(Embodiment 3) As shown in FIG. 7, a lens formed by potting and curing a translucent resin such as a silicone resin (714) instead of using a preformed lens as the lens. A light emitting device of the present invention is obtained in the same manner as in Example 1 except for using. The silicon resin (714) functioning as a lens only needs to be provided so as to cover the protrusions of the support, the light emitting element, and even the wires bonded to the electrodes, and can be used without using a mold or the like. It can be formed into a lens shape using tension.

Example 4 In Example 3, after the silicone resin was cured, a lens material was injected using a mold as shown in FIG. 8 to integrally form a lens having a two-layer structure. Get the device.

[0033]

【The invention's effect】 [Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a light emitting device of the present invention.

FIG. 2 is a schematic sectional view showing another light emitting device of the present invention.

FIG. 3 is a process chart showing a forming step and a repairing step of the light emitting device of the present invention.

FIG. 4 is a schematic sectional view of a light emitting device shown for comparison with the present invention.

FIG. 5 is a schematic sectional view showing another light emitting device of the present invention.

FIG. 6 is a schematic sectional view showing another light emitting device of the present invention.

FIG. 7 is a schematic sectional view showing another light emitting device of the present invention.

FIG. 8 is a schematic sectional view showing another light emitting device of the present invention.

[Explanation of symbols]

101, 201, 501, 601, 701, 801 ... LED chips 102, 202, 502, 602, 702, 802 ... substrates provided with through holes 103, 203, 503, 603, 703, 803 ... leads Conductive patterns 104, 204, 504, 604, 704, 804... Electrical connection members 105, 205, 705, 805... Supports 106, 506, 606 , 706, 806: an insulating layer for electrically separating the metal substrate from the conductive pattern 107, 507, 607, 707, 807: a protrusion for preventing slippage provided on a support member 108: a through hole 209: a lens 210 ... inert gas 301 ... defective LED chip 305 ... support 31 on which a good LED chip is arranged ... Enchingu are electrically isolated isolation trench 401 ... LED chips 402 ... metal substrate 403 ... copper pattern 404 ... gold wire 405 ... SiO ₂ insulating film 511,612 ... support 613 ... continuous lens provided with irregularities 616 ... Fluorescent substances 714, 814: Silicon resin 815: Lens integrally molded

Claims (8)

[Claims] 1. A light emitting device comprising: a substrate (102) having a through hole; a support member (105) that fits into the through hole; and a light emitting element (101) disposed on the support member. 2. The light emitting device according to claim 1, wherein the support member has a higher thermal conductivity than a substrate having a through hole. 3. The light emitting device according to claim 1, wherein the support member (105) is detachable from a through hole of the substrate (102). 4. The light emitting device according to claim 1, wherein the support member has a reflector structure. 5. The light emitting device according to claim 1, wherein the support member is plated. 6. The light emitting device according to claim 1, wherein the substrate is a glass epoxy resin having a conductive pattern formed on a surface thereof. 7. The support member (105) has a bottom portion larger than a surface on which the light emitting element (101) is arranged.
A light-emitting device according to claim 1. 8. The light-emitting device according to claim 1, wherein said support member has a heat-emitting means.