WO2008069605A1 - Light emitting device - Google Patents

Light emitting device Download PDF

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Publication number
WO2008069605A1
WO2008069605A1 PCT/KR2007/006332 KR2007006332W WO2008069605A1 WO 2008069605 A1 WO2008069605 A1 WO 2008069605A1 KR 2007006332 W KR2007006332 W KR 2007006332W WO 2008069605 A1 WO2008069605 A1 WO 2008069605A1
Authority
WO
WIPO (PCT)
Prior art keywords
light emitting
base
leads
emitting device
side portions
Prior art date
Application number
PCT/KR2007/006332
Other languages
French (fr)
Inventor
Hee Chang Jin
Original Assignee
Seoul Semiconductor Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR1020070126225A external-priority patent/KR101456266B1/en
Application filed by Seoul Semiconductor Co., Ltd. filed Critical Seoul Semiconductor Co., Ltd.
Publication of WO2008069605A1 publication Critical patent/WO2008069605A1/en

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/52—Encapsulations
    • H01L33/54—Encapsulations having a particular shape
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/483—Containers
    • H01L33/486—Containers adapted for surface mounting
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48245—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H01L2224/48247—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic connecting the wire to a bond pad of the item
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01079—Gold [Au]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/62—Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Definitions

  • the present invention relates to a light emitting device, and more particularly, to a light emitting device capable of preventing moisture penetration.
  • a light emitting diode is an element in which light is emitted through recombination of electrons and holes in a P-N junction by application of current.
  • a light emitting device using such an LED has less electric power consumption and a longer life span of several to several ten times as compared with conventional light bulbs or fluorescent lamps, thereby having reduced electric power consumption and excellent durability.
  • Such a light emitting device is generally fabricated by installing metallic leads as an external power input member in a body made of a resin material, such as a substrate or housing, mounting an LED on the external power input member, electrically connecting the LED, and then forming a molding member of epoxy or silicon resin to encapsulate the LED.
  • a crack which causes moisture to penetrate between the molding member and the body may be generated due to the metallic leads made of a material different from materials of the conventional light emitting device. External moisture, i.e., water, may penetrate into the light emitting device through such a crack. When moisture penetrates into the light emitting device, either an interface defect may occur between the molding member and the body or cracks may occur in the molding member due to heat generated in the operation of the light emitting device. Therefore, electrical connection between the LED and the lead may be cut off. Disclosure of Invention Technical Problem
  • the present invention is conceived to solve the aforementioned problems in the prior art.
  • An object of the present invention is to provide a light emitting device capable of preventing moisture penetration.
  • a light emitting device which comprises: a housing having a base in the center and side portions in the left and right sides in sectional view; leads formed to surround one and the other sides of the base and having regions covered with the side portions; a light emitting chip positioned on a portion of the leads or the base to be electrically connected to the leads; and a molding member encapsulating the light emitting chip and positioned over the base and the side portions.
  • the side portions extend from the one and the other sides of the base to cover the leads, which are in contact with the one and the other sides of the base, and are formed integrally with the base.
  • the leads has a through-hole formed on a surface in contact with one of the side portions.
  • the side portions respectively adhere to both the left and right sides of the base.
  • the leads are exposed to an outside from a bottom surface of the base opposite to a top surface of the base where the light emitting chip is mounted.
  • the leads surround the one and the other sides of the base in the shape of'D", respectively.
  • the molding member be individually formed of a material different from the housing on a top surface of the housing in a state where the housing supports the leads.
  • the molding member and the housing may be portions formed of the same material and simultaneously and integrally formed to support the leads.
  • FIG. 1 is a perspective view of a light emitting device according to a first embodiment of the present invention.
  • Fig. 2 is a sectional view taken along line A-A in Fig. 1.
  • FIG. 3 is a perspective view of a light emitting device according to a second embodiment of the present invention.
  • Fig. 4 is a sectional view taken along line C-C in Fig. 3.
  • FIG. 5 is a sectional view of a light emitting device according to a third embodiment of the present invention.
  • FIG. 1 is a perspective view of a light emitting device according to a first embodiment of the present invention
  • Fig. 2 is a sectional view taken along line A- A in Fig. 1.
  • the light emitting device comprises a housing 100, leads 120 formed to pass through the housing 100, a light emitting chip 140 mounted on the leads 120, a wire 160 for connecting the lead 120 and the light emitting chip 140, and a molding member 180 for encapsulating the light emitting chip 140 and the wire 160.
  • the housing 100 is a body for supporting and protecting the entire structure of the light emitting device.
  • the housing may be formed of a resin such as poly phthal amid (PPA) or liquid crystal polymer (LCP).
  • PPA poly phthal amid
  • LCP liquid crystal polymer
  • the housing 100 of this embodiment comprises a base 100a in the center thereof and side portions 100b and 100c respectively formed in the left and right sides thereof, with the leads 120 as a boundary.
  • the base 100a is to support the leads 120 and the light emitting chip 140 and to electrically disconnect the leads 120 from one another.
  • the leads 120 are formed at one and the other sides of the base 100a.
  • the light emitting chip 140 may be mounted on a portion of the leads 120, i.e., a first or second lead 120a and 120b.
  • the light emitting chip 140 may be mounted on top of the base 100a to be connected to the first and second leads 120a and 120b through bonding wires.
  • the first and second leads 120a and 120b have a structure in which they surround both sides of the base 100a in the shape of "D".
  • first and second side portions 100b and 100c respectively positioned at one and the other sides of the base 100a.
  • first side portion 100b may be formed at one side of the base 100a, i.e., the left side of the base 100a with the first lead 120a formed thereon
  • second side portion 100c may be formed at the other side of the base 100a, i.e., the right side of the base 100a with the second lead 120b formed thereon.
  • first and second side portions 100b and 100c are respectively formed at both the sides of the base 100a, they are formed to maximally encapsulate portions of the first and second leads 120a and 120b in contact with both the sides of the base 100a, i.e., exposed regions of the first and second leads 120a and 120b except regions for soldering with an external power input member.
  • the width of each of the base 100a and first and second side portions 100b and 100c be larger than that of the leads 120, so that the first and second side portions 100b and 100c can be formed at the base portion 100a.
  • the base 100a and the first and second side portions 100b and 100c may be integrally formed.
  • the base 100a and the first and second side portions 100b and 100c are integrally formed, they may be formed of the same material.
  • the leads 120 are disposed so that they are positioned at the boundary between regions in which the base 100a and the first and second side portions 100b and 100c will be formed in a predetermined mold, and a liquid resin is injected into the mold, thereby fabricating the housing provided with the base 100a and first and second side portions 100b and 100c by the lead.
  • the present invention is not limited thereto. That is, the first and second side portions 100b and 100c may adhere to the base 100a by a method such as adhesion or fusion. At this time, the base 100a and the first and second side portions 100b and 100c may be formed of the same material or different materials.
  • each of the first and second leads 120a and 120a are identical to each of the first and second leads 120a and 120a.
  • first and second leads 120a and 120b has a structure surrounding one or the other side of the base 100a roughly in the shape of "D". Regions of the first and second leads 120a and 120b, i.e., a region between the first side portion 100b and the base 100a and a region between the second side portion 100c and the base, are covered with the first and second side portions 100b and 100c, respectively. The first and second leads 120a and 120b are exposed to the outside only at the top surface of the base where the light emitting chip is mounted and the bottom surface of the base opposite to the top surface.
  • the light emitting device of this embodiment has a molding member
  • the molding member 180 formed over the base 100a and the first and second side portions 100b and 100c to entirely cover the leads 120 (120a and 120b).
  • the molding member 180 is individually formed of a material different from the housing 100 on the top surface thereof in a state where the housing 100 supports the leads 120.
  • the material of the molding member 180 is transparent silicon or epoxy as described below, and the molding method of the molding member 180 is transfer molding suitable for obtaining a desired shape.
  • the molding member 180 is to encapsulate the light emitting chip 140 and to fix the wire 160 connected to the light emitting chip 140. Since the molding member 180 should transmit light emitted from the light emitting chip 140 to the outside, it is formed of a transparent resin such as epoxy or silicon resin. The molding member 180 entirely covers the top surface of the lead 120 that becomes a path of moisture penetration to reduce the amount of moisture penetration from the outside.
  • the molding member 180 encapsulates the light emitting chip 140, fixes the wire
  • the molding member 180 is formed on at least a region of the first and second side portions 100b and 100c and the base 100a to cover boundary regions between the base and the first and second side portions 100b and 100c. Accordingly, the molding member 180 can completely encapsulate exposed regions of the first and second leads 120a and 120b except regions for soldering with an external power input member.
  • the exposed regions of the first and second leads 120a and 120b except regions for soldering with an external power input member are completely encapsulated, thereby covering a crack caused by the leads and allowing a distance by which external moisture penetrates into the light emitting chip 140 to be as long as possible. Accordingly, it is possible to prevent moisture from penetrating into the light emitting device.
  • the light emitting device may further include a diffusing agent (not shown) for diffusing light emitted from the light emitting chip 140 in the molding member 180 to be uniformly emitted.
  • a diffusing agent (not shown) for diffusing light emitted from the light emitting chip 140 in the molding member 180 to be uniformly emitted.
  • Barium titanate, titanium oxide, aluminum oxide, silicon oxide or the like may be used as the diffusing agent.
  • a phosphor (not shown) may be further included in the molding member 180.
  • the phosphor absorbs a portion of light emitted from the light emitting chip 140 and emits light with a wavelength different from the absorbed light.
  • the phosphor comprises activators mixed with impurities at a proper position of host lattice. The activators serve to determine an energy level related to a light emitting process, thereby determining the color of light emitted. The color is determined by an energy gap between ground and excitation states of the activators in a crystal structure.
  • the leads 120 are to apply external power to the light emitting chip 140, and include the first and second leads 120a and 120b respectively formed at both the sides of the base 100a. At this time, portions of the first and second leads 120a and 120b are formed and encapsulated between the molding member 180 and the base 100a and between the base 100a and the first and second side portions 100b and 100c. The other portions of the first and second leads 120a and 120b protrude from the bottom surface of the base 100a opposite to the top surface thereof, where the light emitting chip 140 is mounted, to receive external power.
  • the first and second leads 120a and 120b protruding from the bottom surface of the base 100a extend and are bent toward a central portion of the bottom surface thereof not to be exposed to the outside of the light emitting device.
  • the light emitting chip 140 which has a compound semiconductor laminated structure with a p-n junction, uses a phenomenon in which light is emitted through recombination of minority carriers (electrons or holes).
  • the light emitting chip 140 may comprise first and second semiconductor layers (not shown) and an active layer (not shown) formed between the first and second semiconductor layers.
  • the first semiconductor layer is a P-type semiconductor layer
  • the second semiconductor layer is an N-type semiconductor layer.
  • a P-type electrode (not shown) is formed on a top of the light emitting chip 140, i.e., one surface of the P-type semiconductor layer, and an N-type electrode (not shown) is formed on a bottom of the light emitting chip 140, i.e., one surface of the N-type semiconductor layer.
  • the N-type electrode is in contact with the first lead 120a, and the P-type electrode may be electrically connected to the second lead 120b through the wire 160.
  • the present invention is not limited thereto.
  • a horizontal light emitting chip as well as a vertical light emitting chip described above may be used as the light emitting chip 140 according to the present invention, and various types of light emitting chips emitting visual light, ultraviolet light or the like may be used as the light emitting chip 140.
  • the light emitting chip 140 is mounted on the first lead 120a in this embodiment, the light emitting chip is not limited thereto but may be mounted on the second lead 120b. It will be apparent that the light emitting chip 140 may be mounted on the base 100a and connected to the leads 120 through wires 160.
  • the wire 160 is used to electrically connect the light emitting chip 140 to the second lead 120b, and may be formed of Au or Al through a process such as a wire bonding process. Meanwhile, if the light emitting chip 140 is a horizontal light emitting chip, two wires 160 may be used to electrically connect the horizontal light emitting chip to the first and second leads 120a and 120b.
  • a process such as a wire bonding process.
  • two wires 160 may be used to electrically connect the horizontal light emitting chip to the first and second leads 120a and 120b.
  • FIG. 3 is a perspective view of a light emitting device according to a second embodiment of the present invention
  • Fig. 4 is a sectional view taken along line C- C in Fig. 3.
  • the light emitting device comprises a housing 100, leads 120 formed to pass through the housing 100 and having through-holes 121 formed therein, a light emitting chip 140 mounted on the lead 120, a wire 160 for connecting the lead 120 and the light emitting chip 140 therethrough, and a molding member 180 for encapsulating the light emitting chip 140 and the wire 160.
  • the housing 100 is a body for supporting and protecting the entire structure of the light emitting device and may be formed of a resin such as poly phthal amid (PPA) or liquid crystal polymer (LCP). At this time, the housing 100 according to this embodiment also comprises a base 100a and side portions 100b and 100c as in the first embodiment of the present invention.
  • a resin such as poly phthal amid (PPA) or liquid crystal polymer (LCP).
  • the base 100a is to support the leads 120 and the light emitting chip 140 and to electrically disconnect the leads 120 from one another.
  • the leads 120 are formed at one and the other sides of the base 100a.
  • the side portions 100b and 100c which are to prevent moisture from penetrating between the base 100a and the molding member 180, may comprise first and second side portions 100b and 100c respectively positioned at one and the other sides of the base 100a.
  • the first side portion 100b is formed at one side of the base 100a with the first lead 120a formed thereon to encapsulate a region of the first lead 120a in contact with the one side of the base 100a
  • the second side portion 100c is formed at the other side of the base 100a with the second lead 120b formed thereon to encapsulate a region of the second lead 120b in contact with the other side of the base 100a.
  • the molding member 180 is to encapsulate the light emitting chip 140 and to fix the wire 160 connected to the light emitting chip 140. Since the molding member 180 should transmit light emitted from the light emitting chip 140 to the outside, it is formed of a transparent resin such as epoxy or silicon resin.
  • the molding member 180 is formed on at least a region of the first and second side portions 100b and 100c and on the base 100a to cover boundary regions between the base and the first and second side portions 100b and 100c. Accordingly, the molding member 180 can completely encapsulate exposed regions of the first and second leads 120a and 120b except regions for soldering with an external power input member.
  • the leads 120 are to apply external power to the light emitting chip 140, and include the first and second leads 120a and 120b respectively formed at both the sides of the base 100a.
  • through- holes 121 are respectively formed in the first and second leads 120a and 120b. That is, first and second through-holes 121a and 121b are respectively formed in the first and second leads 120a and 120b so that a contact area between the base 100a and the first and second leads 120a and 120b is enlarged to increase adhesion with the leads.
  • each of the first and second through-holes 121a and 121b includes three holes.
  • the present invention is not limited thereto. That is, the number of holes may be three or less, or more.
  • the exposed regions of the first and second leads 120a and 120b except regions for soldering with an external power input member are completely encapsulated, thereby covering a crack caused by the leads 120 and allowing a distance by which external moisture penetrates into the light emitting chip 140 to be as long as possible. Accordingly, it is possible to prevent moisture from penetrating into the light emitting device.
  • the through-holes 121 are formed in the leads 120, thereby preventing the base 100a and the first and second side portions 100b and 100c from being separated from each other.
  • FIG. 5 is a sectional view of a light emitting device according to a third embodiment of the present invention, showing a structure in which a molding member 180 and a housing 100 are integrally formed, for example, by transfer molding. That is, the molding member 180 and the housing 100 are simultaneously and integrally formed by a single transfer molding process performed in a state where the molding member 180 and the housing 100 support leads 120, and thus, the molding member 180 and the housing 100 are formed of the same material.
  • the molding member 180 and the housing 100 are not divided practically, they are divided with top surfaces of the leads as a boundary in Fig. 5. For convenience of understanding, the boundary is indicated by an imaginary line.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Led Device Packages (AREA)

Abstract

A light emitting device is disclosed. The light emitting device comprises a housing having a base in the center and side portions in the left and right sides in sectional view; leads formed to surround one and the other sides of the base and having regions covered with the side portions; a light emitting chip mounted on a portion of the leads or the base to be electrically connected to the leads; and a molding member encapsulating the light emitting chip and positioned over the base and the side portions so that the leads on the base is entirely covered.

Description

Description LIGHT EMITTING DEVICE
Technical Field
[1] The present invention relates to a light emitting device, and more particularly, to a light emitting device capable of preventing moisture penetration. Background Art
[2] A light emitting diode (LED) is an element in which light is emitted through recombination of electrons and holes in a P-N junction by application of current. A light emitting device using such an LED has less electric power consumption and a longer life span of several to several ten times as compared with conventional light bulbs or fluorescent lamps, thereby having reduced electric power consumption and excellent durability.
[3] Such a light emitting device is generally fabricated by installing metallic leads as an external power input member in a body made of a resin material, such as a substrate or housing, mounting an LED on the external power input member, electrically connecting the LED, and then forming a molding member of epoxy or silicon resin to encapsulate the LED.
[4] At this time, a crack which causes moisture to penetrate between the molding member and the body may be generated due to the metallic leads made of a material different from materials of the conventional light emitting device. External moisture, i.e., water, may penetrate into the light emitting device through such a crack. When moisture penetrates into the light emitting device, either an interface defect may occur between the molding member and the body or cracks may occur in the molding member due to heat generated in the operation of the light emitting device. Therefore, electrical connection between the LED and the lead may be cut off. Disclosure of Invention Technical Problem
[5] The present invention is conceived to solve the aforementioned problems in the prior art. An object of the present invention is to provide a light emitting device capable of preventing moisture penetration. Technical Solution
[6] According to an aspect of the present invention, there is provided a light emitting device, which comprises: a housing having a base in the center and side portions in the left and right sides in sectional view; leads formed to surround one and the other sides of the base and having regions covered with the side portions; a light emitting chip positioned on a portion of the leads or the base to be electrically connected to the leads; and a molding member encapsulating the light emitting chip and positioned over the base and the side portions. [7] Preferably, the side portions extend from the one and the other sides of the base to cover the leads, which are in contact with the one and the other sides of the base, and are formed integrally with the base. [8] Preferably, at least one of the leads has a through-hole formed on a surface in contact with one of the side portions. [9] Preferably, the side portions respectively adhere to both the left and right sides of the base. [10] Preferably, the leads are exposed to an outside from a bottom surface of the base opposite to a top surface of the base where the light emitting chip is mounted. [11] Preferably, the leads surround the one and the other sides of the base in the shape of'D", respectively. [12] It is preferable that the molding member be individually formed of a material different from the housing on a top surface of the housing in a state where the housing supports the leads. The molding member and the housing may be portions formed of the same material and simultaneously and integrally formed to support the leads.
Advantageous Effects
[13] According to the present invention, it is possible to encapsulate the entire region of leads except regions for soldering. Accordingly, a path through which moisture may penetrate into a light emitting device is blocked, thereby fabricating a light emitting device with reliability.
Brief Description of the Drawings [14] Fig. 1 is a perspective view of a light emitting device according to a first embodiment of the present invention.
[15] Fig. 2 is a sectional view taken along line A-A in Fig. 1.
[16] Fig. 3 is a perspective view of a light emitting device according to a second embodiment of the present invention.
[17] Fig. 4 is a sectional view taken along line C-C in Fig. 3.
[18] Fig. 5 is a sectional view of a light emitting device according to a third embodiment of the present invention.
[19] <Explanation of Reference Numerals for Major Portions Shown in Drawings>
[20] 100: Housing 100a: Base
[21] 100b: First side portion 100c: Second side portion
[22] 120: Lead 121: Through-hole
[23] 140: Light emitting chip 160: Wire
[24] 180: Molding member Best Mode for Carrying Out the Invention
[25] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[26] However, the present invention is not limited to the embodiments disclosed below but may be implemented into different forms. These embodiments are provided only for illustrative purposes and for full understanding of the scope of the present invention by those skilled in the art. Throughout the drawings, like reference numerals are used to designate like elements.
[27] Fig. 1 is a perspective view of a light emitting device according to a first embodiment of the present invention, and Fig. 2 is a sectional view taken along line A- A in Fig. 1.
[28] As shown in Figs. 1 and 2, the light emitting device according to the first embodiment of the present invention comprises a housing 100, leads 120 formed to pass through the housing 100, a light emitting chip 140 mounted on the leads 120, a wire 160 for connecting the lead 120 and the light emitting chip 140, and a molding member 180 for encapsulating the light emitting chip 140 and the wire 160.
[29] The housing 100 is a body for supporting and protecting the entire structure of the light emitting device. The housing may be formed of a resin such as poly phthal amid (PPA) or liquid crystal polymer (LCP). At this time, the housing 100 according to this embodiment is generally formed in a rectangular shape.
[30] In sectional view, i.e., as shown in a sectional view of Fig. 2, the housing 100 of this embodiment comprises a base 100a in the center thereof and side portions 100b and 100c respectively formed in the left and right sides thereof, with the leads 120 as a boundary.
[31] The base 100a is to support the leads 120 and the light emitting chip 140 and to electrically disconnect the leads 120 from one another. The leads 120 are formed at one and the other sides of the base 100a. As shown in these figures, the light emitting chip 140 may be mounted on a portion of the leads 120, i.e., a first or second lead 120a and 120b. The light emitting chip 140 may be mounted on top of the base 100a to be connected to the first and second leads 120a and 120b through bonding wires. The first and second leads 120a and 120b have a structure in which they surround both sides of the base 100a in the shape of "D".
[32] The side portions, which are to prevent moisture from penetrating between the base
100a and the molding member 180, may comprise first and second side portions 100b and 100c respectively positioned at one and the other sides of the base 100a. At this time, the first side portion 100b may be formed at one side of the base 100a, i.e., the left side of the base 100a with the first lead 120a formed thereon, and the second side portion 100c may be formed at the other side of the base 100a, i.e., the right side of the base 100a with the second lead 120b formed thereon. In addition, when the first and second side portions 100b and 100c are respectively formed at both the sides of the base 100a, they are formed to maximally encapsulate portions of the first and second leads 120a and 120b in contact with both the sides of the base 100a, i.e., exposed regions of the first and second leads 120a and 120b except regions for soldering with an external power input member. At this time, it is preferred that the width of each of the base 100a and first and second side portions 100b and 100c be larger than that of the leads 120, so that the first and second side portions 100b and 100c can be formed at the base portion 100a. In addition, the base 100a and the first and second side portions 100b and 100c may be integrally formed. In a case where the base 100a and the first and second side portions 100b and 100c are integrally formed, they may be formed of the same material. For example, the leads 120 are disposed so that they are positioned at the boundary between regions in which the base 100a and the first and second side portions 100b and 100c will be formed in a predetermined mold, and a liquid resin is injected into the mold, thereby fabricating the housing provided with the base 100a and first and second side portions 100b and 100c by the lead.
[33] However, the present invention is not limited thereto. That is, the first and second side portions 100b and 100c may adhere to the base 100a by a method such as adhesion or fusion. At this time, the base 100a and the first and second side portions 100b and 100c may be formed of the same material or different materials.
[34] As has been briefly described above, each of the first and second leads 120a and
120b has a structure surrounding one or the other side of the base 100a roughly in the shape of "D". Regions of the first and second leads 120a and 120b, i.e., a region between the first side portion 100b and the base 100a and a region between the second side portion 100c and the base, are covered with the first and second side portions 100b and 100c, respectively. The first and second leads 120a and 120b are exposed to the outside only at the top surface of the base where the light emitting chip is mounted and the bottom surface of the base opposite to the top surface.
[35] Meanwhile, the light emitting device of this embodiment has a molding member
180 formed over the base 100a and the first and second side portions 100b and 100c to entirely cover the leads 120 (120a and 120b). At this time, the molding member 180 is individually formed of a material different from the housing 100 on the top surface thereof in a state where the housing 100 supports the leads 120. Preferably, the material of the molding member 180 is transparent silicon or epoxy as described below, and the molding method of the molding member 180 is transfer molding suitable for obtaining a desired shape.
[36] The molding member 180 is to encapsulate the light emitting chip 140 and to fix the wire 160 connected to the light emitting chip 140. Since the molding member 180 should transmit light emitted from the light emitting chip 140 to the outside, it is formed of a transparent resin such as epoxy or silicon resin. The molding member 180 entirely covers the top surface of the lead 120 that becomes a path of moisture penetration to reduce the amount of moisture penetration from the outside.
[37] , the molding member 180 encapsulates the light emitting chip 140, fixes the wire
160, and prevents external moisture from reaching the light emitting chip 140 together with the first and second side portions 100b and 100c. That is, the molding member 180 is formed on at least a region of the first and second side portions 100b and 100c and the base 100a to cover boundary regions between the base and the first and second side portions 100b and 100c. Accordingly, the molding member 180 can completely encapsulate exposed regions of the first and second leads 120a and 120b except regions for soldering with an external power input member.
[38] As described above, according to the present invention, the exposed regions of the first and second leads 120a and 120b except regions for soldering with an external power input member are completely encapsulated, thereby covering a crack caused by the leads and allowing a distance by which external moisture penetrates into the light emitting chip 140 to be as long as possible. Accordingly, it is possible to prevent moisture from penetrating into the light emitting device.
[39] Meanwhile, the light emitting device according to this embodiment may further include a diffusing agent (not shown) for diffusing light emitted from the light emitting chip 140 in the molding member 180 to be uniformly emitted. Barium titanate, titanium oxide, aluminum oxide, silicon oxide or the like may be used as the diffusing agent. A phosphor (not shown) may be further included in the molding member 180. The phosphor absorbs a portion of light emitted from the light emitting chip 140 and emits light with a wavelength different from the absorbed light. The phosphor comprises activators mixed with impurities at a proper position of host lattice. The activators serve to determine an energy level related to a light emitting process, thereby determining the color of light emitted. The color is determined by an energy gap between ground and excitation states of the activators in a crystal structure.
[40] The leads 120 are to apply external power to the light emitting chip 140, and include the first and second leads 120a and 120b respectively formed at both the sides of the base 100a. At this time, portions of the first and second leads 120a and 120b are formed and encapsulated between the molding member 180 and the base 100a and between the base 100a and the first and second side portions 100b and 100c. The other portions of the first and second leads 120a and 120b protrude from the bottom surface of the base 100a opposite to the top surface thereof, where the light emitting chip 140 is mounted, to receive external power. Preferably, the first and second leads 120a and 120b protruding from the bottom surface of the base 100a extend and are bent toward a central portion of the bottom surface thereof not to be exposed to the outside of the light emitting device.
[41] The light emitting chip 140, which has a compound semiconductor laminated structure with a p-n junction, uses a phenomenon in which light is emitted through recombination of minority carriers (electrons or holes). The light emitting chip 140 may comprise first and second semiconductor layers (not shown) and an active layer (not shown) formed between the first and second semiconductor layers. In this embodiment, the first semiconductor layer is a P-type semiconductor layer, and the second semiconductor layer is an N-type semiconductor layer. A P-type electrode (not shown) is formed on a top of the light emitting chip 140, i.e., one surface of the P-type semiconductor layer, and an N-type electrode (not shown) is formed on a bottom of the light emitting chip 140, i.e., one surface of the N-type semiconductor layer. At this time, the N-type electrode is in contact with the first lead 120a, and the P-type electrode may be electrically connected to the second lead 120b through the wire 160. However, the present invention is not limited thereto. That is, a horizontal light emitting chip as well as a vertical light emitting chip described above may be used as the light emitting chip 140 according to the present invention, and various types of light emitting chips emitting visual light, ultraviolet light or the like may be used as the light emitting chip 140. Meanwhile, although the light emitting chip 140 is mounted on the first lead 120a in this embodiment, the light emitting chip is not limited thereto but may be mounted on the second lead 120b. It will be apparent that the light emitting chip 140 may be mounted on the base 100a and connected to the leads 120 through wires 160.
[42] The wire 160 is used to electrically connect the light emitting chip 140 to the second lead 120b, and may be formed of Au or Al through a process such as a wire bonding process. Meanwhile, if the light emitting chip 140 is a horizontal light emitting chip, two wires 160 may be used to electrically connect the horizontal light emitting chip to the first and second leads 120a and 120b. Mode for the Invention
[43] Hereinafter, light emitting devices according to other embodiments of the present invention will be described with reference to the accompanying drawings. Some descriptions overlapping with the aforementioned descriptions of the light emitting device according the first embodiment of the present invention will be omitted or briefly described herein.
[44] Fig. 3 is a perspective view of a light emitting device according to a second embodiment of the present invention, and Fig. 4 is a sectional view taken along line C- C in Fig. 3.
[45] As shown in Figs. 3 and 4, the light emitting device according to this embodiment comprises a housing 100, leads 120 formed to pass through the housing 100 and having through-holes 121 formed therein, a light emitting chip 140 mounted on the lead 120, a wire 160 for connecting the lead 120 and the light emitting chip 140 therethrough, and a molding member 180 for encapsulating the light emitting chip 140 and the wire 160.
[46] The housing 100 is a body for supporting and protecting the entire structure of the light emitting device and may be formed of a resin such as poly phthal amid (PPA) or liquid crystal polymer (LCP). At this time, the housing 100 according to this embodiment also comprises a base 100a and side portions 100b and 100c as in the first embodiment of the present invention.
[47] The base 100a is to support the leads 120 and the light emitting chip 140 and to electrically disconnect the leads 120 from one another. The leads 120 are formed at one and the other sides of the base 100a.
[48] The side portions 100b and 100c , which are to prevent moisture from penetrating between the base 100a and the molding member 180, may comprise first and second side portions 100b and 100c respectively positioned at one and the other sides of the base 100a. At this time, the first side portion 100b is formed at one side of the base 100a with the first lead 120a formed thereon to encapsulate a region of the first lead 120a in contact with the one side of the base 100a, and the second side portion 100c is formed at the other side of the base 100a with the second lead 120b formed thereon to encapsulate a region of the second lead 120b in contact with the other side of the base 100a.
[49] The molding member 180 is to encapsulate the light emitting chip 140 and to fix the wire 160 connected to the light emitting chip 140. Since the molding member 180 should transmit light emitted from the light emitting chip 140 to the outside, it is formed of a transparent resin such as epoxy or silicon resin.
[50] The molding member 180 is formed on at least a region of the first and second side portions 100b and 100c and on the base 100a to cover boundary regions between the base and the first and second side portions 100b and 100c. Accordingly, the molding member 180 can completely encapsulate exposed regions of the first and second leads 120a and 120b except regions for soldering with an external power input member.
[51] The leads 120 are to apply external power to the light emitting chip 140, and include the first and second leads 120a and 120b respectively formed at both the sides of the base 100a. At this time, in the leads 120 according to this embodiment, through- holes 121 are respectively formed in the first and second leads 120a and 120b. That is, first and second through-holes 121a and 121b are respectively formed in the first and second leads 120a and 120b so that a contact area between the base 100a and the first and second leads 120a and 120b is enlarged to increase adhesion with the leads. In this embodiment, each of the first and second through-holes 121a and 121b includes three holes. However, the present invention is not limited thereto. That is, the number of holes may be three or less, or more.
[52] As described above, in this embodiment, the exposed regions of the first and second leads 120a and 120b except regions for soldering with an external power input member are completely encapsulated, thereby covering a crack caused by the leads 120 and allowing a distance by which external moisture penetrates into the light emitting chip 140 to be as long as possible. Accordingly, it is possible to prevent moisture from penetrating into the light emitting device. In addition, the through-holes 121 are formed in the leads 120, thereby preventing the base 100a and the first and second side portions 100b and 100c from being separated from each other.
[53] Fig. 5 is a sectional view of a light emitting device according to a third embodiment of the present invention, showing a structure in which a molding member 180 and a housing 100 are integrally formed, for example, by transfer molding. That is, the molding member 180 and the housing 100 are simultaneously and integrally formed by a single transfer molding process performed in a state where the molding member 180 and the housing 100 support leads 120, and thus, the molding member 180 and the housing 100 are formed of the same material. Although the molding member 180 and the housing 100 are not divided practically, they are divided with top surfaces of the leads as a boundary in Fig. 5. For convenience of understanding, the boundary is indicated by an imaginary line.

Claims

Claims
[1] A light emitting device, comprising: a housing having a base in the center and side portions in the left and right sides in sectional view; leads formed to surround one and the other sides of the base and having regions covered with the side portions; a light emitting chip positioned on a portion of the leads or the base to be electrically connected to the leads; and a molding member encapsulating the light emitting chip and positioned over the base and the side portions. [2] The light emitting device as claimed in claim 1, wherein the side portions extend from the one and the other sides of the base to cover the leads, which are in contact with the one and the other sides of the base, and are formed integrally with the base. [3] The light emitting device as claimed in claim 1, wherein at least one of the leads has a through-hole formed on a surface in contact with one of the side portions. [4] The light emitting device as claimed in claim 1, wherein the side portions respectively adhere to both the left and right sides of the base. [5] The light emitting device as claimed in claim 1, wherein the leads are exposed to an outside from a bottom surface of the base opposite to a top surface of the base where the light emitting chip is mounted. [6] The light emitting device as claimed in claim 1, wherein the leads surround the one and the other sides of the base in the shape of'D", respectively. [7] The light emitting device as claimed in claim 1, wherein the molding member is individually formed of a material different from the housing on a top surface of the housing in a state where the housing supports the leads. [8] The light emitting device as claimed in claim 1, wherein the molding member and the housing are portions formed of the same material and simultaneously and integrally formed to support the leads.
PCT/KR2007/006332 2006-12-08 2007-12-07 Light emitting device WO2008069605A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR20060124778 2006-12-08
KR10-2006-0124778 2006-12-08
KR1020070126225A KR101456266B1 (en) 2006-12-08 2007-12-06 Light emitting device
KR10-2007-0126225 2007-12-06

Publications (1)

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WO2008069605A1 true WO2008069605A1 (en) 2008-06-12

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Country Link
WO (1) WO2008069605A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5475241A (en) * 1992-08-20 1995-12-12 Hewlett-Packard Company Light source and technique for mounting light emitting diodes
JP2004335740A (en) * 2003-05-07 2004-11-25 Citizen Electronics Co Ltd Light emitting diode and its package structure
KR20050066030A (en) * 2003-12-26 2005-06-30 삼성전기주식회사 High power light emitting diode package and method of producing the same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5475241A (en) * 1992-08-20 1995-12-12 Hewlett-Packard Company Light source and technique for mounting light emitting diodes
JP2004335740A (en) * 2003-05-07 2004-11-25 Citizen Electronics Co Ltd Light emitting diode and its package structure
KR20050066030A (en) * 2003-12-26 2005-06-30 삼성전기주식회사 High power light emitting diode package and method of producing the same

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