JP4923711B2 - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-mounting package light emitting device which does not reduce the productivity, can keep a joining strength at a second bonding position of a light emitting element, and can relax the thermal impact fatigue of bonding connection wiring to a protection element without changing the existing process order and number of processes, when assembling the light emitting element and protection element to be reversely connected in parallel with each other. <P>SOLUTION: The light emitting element 16 and the protection element 17 having a suitable Zener voltage are mounted on a bottom 10b inside a recess 10a formed on an upper surface of a surface mounting package 10, and those elements are reversely connected in parallel with each other. In this case, conductive wires 201-203 are connected to an n-side electrode and p-side electrode on the upper surface of the light emitting element, and an electrode on an upper surface of the protection element, between a conductive member 132 on a first area 111 or a conductive member 133 on a second area 112 on upper surfaces of steps higher than those in its neighborhood. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a light emitting device, and in particular, a bare chip of a light emitting diode (LED) using a nitride semiconductor light emitting element capable of emitting light from the ultraviolet region to visible light and a bare chip of a protective element are mounted in a face-up state to transmit light. The present invention relates to a light emitting device having a structure sealed with a resin.

  Today, various light emitting diodes (LEDs) and laser diodes (LDs) have been developed as semiconductor light emitting devices. Such a semiconductor light emitting device takes advantage of low voltage drive, small size, light weight, thin shape, long life, high reliability and low power consumption, and as a light source such as a display, backlight, indicator, etc. Some are being replaced.

  In particular, a light emitting element that can emit light efficiently from the ultraviolet region to the short wavelength side of visible light has been developed using a nitride semiconductor. An LED having a quantum well structure using a nitride semiconductor (for example, InGaN mixed crystal) as a light emitting (active) layer and emitting light of 10 candela or more in a blue or green region has been developed and commercialized. Combining such an LED chip and a phosphor, a light-emitting device capable of emitting mixed-color light including white light by mixing light from the LED chip and light from the phosphor excited by the light. Can do.

  Since light emitting devices using LEDs are small, consume less power and have a long service life, they are used in a wide range of fields such as liquid crystal backlights and in-vehicle use. The light emitted from the LED is limited monochromatic light such as red, green, and blue, and a fluorescent material for converting it to a different wavelength may be used in combination with the light emitting element. In this case, a light-emitting device that emits white light by adding and mixing light emitted directly from the LED, light emitted from the LED, and wavelength-converted light emitted from the fluorescent material is known. .

On the other hand, an LED using a group III nitride semiconductor (In _x Al _y Ga _1-xy N, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1) for the light emitting layer emits light with high brightness from near ultraviolet to red. It is possible to have a small size, high efficiency, and excellent characteristics of high output with a small current, but due to the structure, the element is easily damaged by an electric shock such as static electricity, and the static electricity below the voltage that humans feel shock There is a problem that it is easily destroyed by voltage. For example, a light emitting diode that can emit red light and infrared light whose normal light emitting layer is made of AlGaInP has a withstand voltage of about 2 KV, whereas blue, green, and yellow light emitting layers that are made of InGaN can emit light. The withstand voltage of the light emitting diode is only about 0.5V or less. In particular, the LED using a nitride semiconductor capable of emitting ultraviolet light containing Al is about 0.2 KV or less.

  Therefore, the applicant of the present application connects a Zener diode (ZD) in antiparallel to the LED as a countermeasure against static electricity / surge protection of the LED using a Group 3 nitride semiconductor in the light emitting layer, without impairing the characteristic specific to the light emitting element. A structure that prevents light-emitting elements from being damaged by static electricity or surge voltage and improves luminous efficiency has been proposed (for example, Patent Document 1).

  By the way, in the conventional structure of the surface mount package type LED device that can be reduced in thickness and size, the mounting surface of the LED chip and the mounting surface of the ZD chip are in the same plane at the bottom surface of the recessed portion of the package. In addition, the other end of the Au fine wire, one end of which is bonded to one electrode of the LED chip, is bonded (2nd bonding) on the Au plating near the ZD chip in the same plane as the ZD chip mounting surface. Yes. In this case, the surface on which the ZD chip is mounted and the portion where the Au thin wire is bonded and connected to the bottom surface of the concave portion of the package are plated with Au on the surface of the metal lead member, and the ZD chip is made of Ag paste. Bonded to the mounting surface.

  However, in the conventional structure described above, the Ag paste bleeds on the ZD chip mounting surface (Au plating surface), and this bleed reaches the 2nd bonding position of the LED chip near the ZD chip, thereby causing the 2nd bonding position. It is desirable to avoid a decrease in the bonding strength between the Au thin wire connected to the lead wire and the Au plated surface of the lead member.

  In the above-described conventional structure, the size of the ZD chip is relatively large, and the length of the Au fine wire from the ZD chip to the 2nd bonding position of the ZD chip is relatively long for the convenience of the ZD chip layout design. . Thus, if the Au fine wire is relatively long, the fatigue degree of the Au fine wire by the thermal shock test of the surface mount type LED product increases.

Patent Document 2 discloses that in a bullet-type (lamp-type) LED device, a ZD is directly electrically connected between two leads, and the tip of the lead frame is located higher than the LED chip. Patent Document 3 discloses an LED module in which the surface of the wiring board is positioned higher than the LED chip.
Japanese Patent Laying-Open No. 2005-20038 JP 2004-119431 A JP-A-11-54803

  In order to avoid a decrease in the bonding strength between the Au fine wire at the 2nd bonding position of the LED chip and the Au plating surface of the lead member due to the bleeding of the Ag paste for bonding the ZD chip as described above, If the order is changed so that the ZD chip is mounted after the 2nd bonding of the LED chip is performed, the number of times of movement between the processes increases, and the mass productivity decreases. Further, in order to avoid the above-described problem, a step is formed by arranging an Au bump in advance at the 2nd bonding position of the LED chip so that the 2nd bonding position is slightly higher than the ZD chip bonding surface. If the LED chip is changed so as to perform 2nd bonding, the number of steps for arranging Au bumps increases.

  In view of such circumstances, the present invention provides an LED chip without reducing the mass productivity without changing the existing process sequence and the number of processes when assembling the LED chip and the ZD chip connected in reverse parallel to each other. It is an object of the present invention to provide a surface-mount package type light emitting device that can secure the bonding strength at the 2nd bonding position and can reduce the thermal shock fatigue of the bonding connection wiring to the ZD chip.

According to a first aspect of the light emitting device of the present invention, the light emitting element and the protective element are joined on the same plane at the bottom surface in the recess formed on the upper surface of the package, and the light emitting element and the protective element are connected in reverse parallel to each other. A surface-mount package type light-emitting device, provided at a peripheral portion of a bottom surface in the concave portion higher than the light-emitting element or the protection element, and at least at a junction of the protection element on the bottom surface A first conductive member, a second conductive member provided in a first region in the vicinity of the top surface of the light emitting element on the top surface of the stepped portion, a vicinity of the top surface of the light emitting element in a top surface of the stepped portion, and Bonding connection between the third conductive member provided in the second region in the vicinity of the upper surface of the protection element, and the first electrode on the upper surface of the light emitting element and the second conductive member in the first region. First conductive wire A second conductive wire bonded between the second electrode on the upper surface of the light emitting element and the third conductive member in the second region, the electrode on the upper surface of the protective element, and the A third conductive wire bonded to and connected to the third conductive member in the second region, and the second region of the step portion is formed so as to swell toward the inside of the recess. The second conductive wire and the third conductive wire are bonded and connected to the third conductive member in the upper surface region of the portion formed so as to swell toward the inside of the recess .

According to a second aspect of the light emitting device of the present invention, an insulating package having a concave portion for accommodating a chip on the top surface and a peripheral portion of the bottom surface in the concave portion are mounted on the same plane at the bottom surface. A step provided higher than the light emitting element or the protective element, a first conductive member extending from at least a part of the upper surface of the bottom surface through the package side wall to the first side surface of the package, and A second conductive member drawn out from the first region on the top surface through the package side wall and connected to the first conductive member on the first side surface; and the first region on the top surface of the stepped portion Is joined to the third conductive member drawn out from the electrically insulated second region through the package side wall to the second side surface of the package and face-up on the bottom surface in the recess. Luminous element The protective element in which a lower surface side electrode is bonded to the first conductive member by a conductive paste in the vicinity of the second region on the bottom surface, the first electrode on the upper surface of the light emitting element, and the first A first conductive wire bonded to the second conductive member on the first region; a second electrode on the upper surface of the light emitting element; and an upper surface of the step portion near the upper surface of the light emitting element. A second conductive wire bonded to the third conductive member on the second region, the upper surface side electrode of the protective element, and the upper surface of the step portion near the upper surface of the protective element. A third conductive wire bonded to the third conductive member on the second region, and a light-transmitting member that seals the light emitting element, the protective element, and the conductive wire in the recess. And a light-emitting element. Protection element are connected in antiparallel to each other, the second region of the stepped portion is formed to bulge into the recess inwardly, the second conductive wire and the third conductive wire, wherein Bonding connection is made between the third conductive member in the upper surface region of the portion formed so as to swell toward the inside of the recess.

  The first conductive member or the second conductive member is drawn out as a first external connection terminal to the lower end portion of the first side surface of the package, and the third conductive member is extended to the lower end portion of the second side surface of the package. It can be pulled out as two external connection terminals. The distance from the bonding position of the protective element to the second region is preferably not more than the distance from the bonding position of the light emitting element to the second region, and is preferably as short as possible. Furthermore, a polarity identification mark may be formed in the vicinity of the outer edge on the first region side on the upper end surface of the package.

  When the protective element is formed on the p substrate, the p-side electrode surface is bonded to the bottom surface of the recess, and the light-emitting element has the n-side electrode on the first region side and the p-side electrode on the second side. It arrange | positions so that it may be located in the area | region side. The first conductive wire is bonded to the n-side electrode of the light emitting element and the second conductive member on the first region, and the third conductive on the p-side electrode of the light emitting element and the second region is connected. A second conductive wire is bonded to the member, and a third conductive wire is bonded to the n-side electrode of the light emitting element and the third conductive member on the second region.

  On the other hand, when the protective element is formed on the n substrate, the n-side electrode surface is bonded to the bottom surface of the recess, and the light-emitting element has the p-side electrode on the first region side and the n-side electrode. Is disposed on the second region side. The first conductive wire is bonded to the p-side electrode of the light emitting element and the second conductive member on the first region, and the third conductive on the n-side electrode of the light emitting element and the second region is connected. A second conductive wire is bonded to the member, and a third conductive wire is bonded to the p-side electrode of the light emitting element and the third conductive member on the second region.

  According to the light emitting device of the first aspect, it is possible to secure the bonding strength at the 2nd bonding position of the light emitting element. Further, with respect to the pair of electrodes on the upper surface of the light emitting element and the electrode on the upper surface of the protective element, between the conductive member on the first region or the conductive member on the second region on the upper surface of the stepped portion higher than that. Conductive wires are bonded to each other. Therefore, since it is not affected by the bleed from the joint portion of the protective element at the 2nd bonding position of the light emitting element, it is possible to ensure the bonding strength of the light emitting element at the 2nd bonding position. In addition, since it is not necessary to change the existing process sequence and the number of processes when assembling the light emitting element and the protective element connected in reverse parallel to each other, the mass productivity is not lowered.

  According to the light emitting device of claim 2, the specific structure of the light emitting device of claim 1 can be provided.

  According to the light emitting device of the third aspect, the distance from the bonding position of the protective element on the inner bottom surface of the package recess to the second region is set shorter than the distance from the bonding position of the light emitting element to the second region. Thus, the conductive wire bonded to the electrode on the upper surface of the protection element and the conductive member on the second region can be short. Therefore, the thermal shock fatigue degree of the bonding connection wiring with respect to the protective element can be reduced.

  According to the light emitting device of the fourth aspect, by using a protective element having a small size formed on the p substrate, two elements (on the same surface at the bottom of the recess are formed even if the bottom of the recess of the package is narrower than the conventional product). A light emitting element and a protective element) can be easily mounted.

  According to the light emitting device of the fifth aspect, it is possible to obtain a standard protective element formed on the n substrate at a low cost, and the manufacturing cost can be suppressed.

  According to the light emitting device of the sixth aspect, the first conductive member or the second conductive member is drawn out as the first external connection terminal to the lower end portion of the first side surface, and the third conductive member is the second conductive member. Since the second external connection terminal is drawn out to the lower end portion of the side surface, the surface mount package can be reduced in thickness and size.

  A light-emitting device according to the present invention includes a light-emitting element using, for example, a group III nitride semiconductor as a light-emitting layer on a bottom surface in a recess formed on the upper surface of a package, and a protective element having a Zener voltage appropriate for the light-emitting element. Are mounted, and both elements are connected in reverse parallel to each other. In this case, with respect to the n-side electrode, the p-side electrode on the upper surface of the light emitting element, and the electrode on the upper surface of the protective element, the conductive member of the first region or the second region on the upper surface of the step portion higher in the vicinity thereof Conductive wires are bonded to the conductive members, respectively.

  Hereinafter, embodiments and examples of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments and examples. In this description, common parts are denoted by common reference numerals throughout the drawings.

<First Embodiment>
FIG. 1 is a partially transparent perspective view schematically showing an example of a surface-mount package type LED device according to the first embodiment of the present invention. FIG. 2 is a partially transparent plan view schematically showing the LED device of FIG. 3 is a cross-sectional view schematically showing a cross-sectional structure in the arrow direction along the AA line in FIG. 2, and FIG. 4 is a schematic cross-sectional structure in the arrow direction along the BB line in FIG. 5 is a cross-sectional view schematically showing a cross-sectional structure in the direction of the arrow along the line CC in FIG. 2, and FIG. 6 is a cross-sectional view in the direction of the arrow along the line DD in FIG. It is sectional drawing which shows a cross-sectional structure schematically.

  In the LED device shown in FIGS. 1 to 6, the package 10 has a recess 10a for accommodating an element on the top surface of an insulating material, and a step portion 11 exists in the peripheral portion of the bottom surface 10b inside the recess. The height of the step portion 11 is higher than the elements 16 and 17 mounted on the bottom surface 10b. Then, on the bottom surface, the first conductive member 131 is pulled out from at least the joint portion of the protective element through the package side wall to the first side surface 121 of the package. Further, the second conductive member 132 is drawn out from the first region 111 on the upper surface of the stepped portion 11 so as to penetrate the package side wall and continue to the first conductive member 131 on the first side surface 121. Further, the third conductive member 133 is drawn out from the second region 112 on the upper surface of the step portion 11 so as to penetrate the package side wall and continue to the second side surface 122 of the package. The conductive member 131 in the first region 111 and the conductive member 132 in the second region 112 on the upper surface of the step portion 11 are electrically insulated by the package insulating material and are substantially on the same plane.

  Further, the first conductive member 131 or the second conductive member 132 is drawn out as the first external connection terminal 141 to the lower end portion of the first side surface 121, and the third conductive member 133 is the second side surface 122. The second external connection terminal 142 is led out to the lower end of the second external connection terminal 142. Further, on the upper end surface of the package, a bar-shaped polarity identification mark 15 made of, for example, a conductive member is formed in the vicinity of the outer edge on the first region 111 side.

  On the bottom surface 10b, a light emitting element 16 that is a gallium nitride-based compound semiconductor and a protective element 17 having an appropriate Zener voltage for protecting the light emitting element 16 are mounted. In this case, the light emitting element 16 has a pair of electrodes (n-side electrode 16n and p-side electrode 16p) formed on one surface (upper surface), and the other surface (lower surface) is bonded to the recess bottom surface 10b by, for example, epoxy resin 18. ing. The protection element 17 is formed by separating the n-side electrode and the p-side electrode on both sides, and the lower surface (one electrode) is a first conductive member (for example, on the recess bottom surface 10b in the vicinity of the second region 112). A conductive paste (Ag paste in this example) 19 is joined to the Au plating surface 131.

  Then, the second conductive member 132 or the second conductive member 132 in the first region 111 on the upper surface of the step portion 11 with respect to the n-side electrode 16 n and the p-side electrode 16 p on the upper surface of the light emitting element 16 and the electrode on the upper surface of the protection element 17. Any one of the conductive wires 201 to 203 is bonded to the third conductive member 133 in the region 112. In this case, one electrode of the light emitting element 16 and the lower surface side electrode of the protection element 17 are connected in common to the first external connection terminal region 141, and the other electrode of the light emitting element 16 is connected to the second external connection terminal 142. By connecting the electrode and the upper surface side electrode of the protective element 17 in common, the protective element 17 is electrically connected in reverse parallel to the light emitting element 16.

  The distance from the bonding position of the protective element 17 to the second region 112 on the package recess bottom surface 10b is preferably set as short as possible below the distance from the bonding position of the light emitting element 16 to the second region 112. Accordingly, the third conductive wire 203 bonded to the electrode on the upper surface of the protection element 17 and the third conductive member 133 on the second region 112 can be shortened. In the conventional product, the conductive wire for 2nd bonding of the protective element is longer than the conductive wire for 2nd bonding of the light emitting element.

  Further, in the package recess 10a, in order to protect the elements 16, 17 and the conductive wires 201 to 203 from external stress, moisture, dust, and the like, and to obtain appropriate light distribution characteristics, a light-transmitting seal is provided. It is sealed with a member 21 (not shown in FIGS. 1 and 2). The translucent sealing member 21 is, for example, an epoxy resin, a silicone resin, a modified silicone resin or the like excellent in light transmissivity. The sealing with the resin can be performed by dropping a liquid resin by, for example, a potting method and heating and curing so that at least the conductive wires 201 to 203 in the package recess 10a are buried. The translucent member may be mixed with a fluorescent material that absorbs light from the light emitting element and converts the wavelength of light to a different wavelength. Further, a diffusing agent may be mixed in order to suppress color unevenness that has a light diffusing action that favorably diffusely reflects light from the fluorescent material and is likely to occur when a fluorescent material having a large particle diameter is used. In addition, it has the effect of increasing the thermal shock resistance of the translucent resin, and can prevent disconnection of the conductive wire, cracking of the resin, peeling between the bottom surface of the LED and the bottom surface of the recess of the package even when used at high temperatures. You may mix the filler which becomes possible.

  When surface-mounting the LED device having the above structure, the bottom surface of the package 10 is mounted on a mounting substrate (not shown), and a pair of external connections drawn to the lower ends of the pair of opposing side surfaces 121 and 122 of the package. The terminals 141 and 142 are fixed and electrically connected to a wiring portion on the mounting substrate by soldering, for example.

  According to the LED device according to the first embodiment described above, the light emitting element 16 using a group III nitride semiconductor for the light emitting layer on the package recess bottom surface 10b, and the protection having an appropriate Zener voltage for the light emitting element. Since the element 17 is mounted and both the elements 16 and 17 are connected in reverse parallel to each other, the element 17 is protected from static electricity and surge voltage, and the characteristic unique to the light emitting element is not impaired.

  Then, the first conductive member 131 in the first region 111 on the upper surface of the step portion 11 higher than the n-side electrode 16n, the p-side electrode 16p on the upper surface of the light emitting element 16 and the electrode on the upper surface of the protection element 17 is used. Alternatively, conductive wires are bonded to the second conductive member 132 in the second region 112, respectively.

  Therefore, the light emitting element 16 is not affected by the bleeding from the joint portion of the protective element 17 at the 2nd bonding position of the light emitting element 16, so that the bonding strength of the light emitting element 16 at the 2nd bonding position can be ensured. In addition, since it is not necessary to change the existing process sequence and the number of processes when assembling the light emitting element 16 and the protective element 17, mass productivity is not lowered.

  Further, the distance from the upper surface electrode of the light emitting element 16 to the first region 111 or the second region 112 is shorter than the distance from the upper surface electrode of the light emitting element to the 2nd bonding position on the bottom surface of the package recess in the conventional product. The length of the conductive wires 202 and 203 to be used can be short. Similarly, the distance from the upper surface electrode of the protection element 17 to the second region 112 is shorter than the distance from the upper surface electrode of the protection element to the 2nd bonding position on the bottom surface of the package recess in the conventional product. The length of 203 is short.

  Further, as described above, the distance from the upper surface electrode of the protective element 17 to the second region 112 on the package recess bottom surface 10b is set to be as short as possible below the distance from the upper surface electrode of the light emitting element 16 to the second region 112. It is desirable. Thereby, the conductive wire 203 bonded to the electrode on the upper surface of the protection element 17 and the third conductive member 133 in the second region 112 can be shortened. Therefore, the thermal shock fatigue degree of the bonding connection wiring with respect to the protective element 17 can be reduced.

  Further, as described above, when the protection element 17 formed on the p substrate is used, even if the package recess bottom surface 10b is narrower than the conventional product, the two elements 16, 17 on the same plane at the recess bottom surface 10b. Can be easily implemented. In addition, the polarity identification mark 15 on the upper end surface of the package has a meaning as a cathode mark indicating that the first external connection terminal 141 of the first side surface 121 of the package is on the n-side electrode side of the LED device, There is an advantage having the same meaning as the polarity identification attached to the upper end surface of the conventional package.

  Hereinafter, each configuration in the first embodiment will be described in detail.

  (Package 10) The package 10 is not limited to the above-described configuration, and metal plating (for example, Au plating) is formed as a conductive member on some of the insulating materials among the plurality of insulating materials. You may have the structure sintered in the state laminated | stacked so that it might pull out to a pair of opposing side surfaces 12 and 122 from the one part interlayer of insulating material. In this case, each insulating material is configured such that a concave portion 10a for housing an element is formed on the upper surface of the package, and a step portion 11 is present on the outer peripheral portion of the concave bottom surface 10b. In addition, Au plating is applied to the bottom surface 10b of the recess, and this Au plating is drawn out to the first side surface 121 of the package, and further continues to the lower end along the side surface, and the first external connection terminal 141 and It has become. Further, on the upper surface of the step portion 11, Au plating is applied to the first region 111 close to the first external connection terminal side so as to continue to the first external connection terminal 141, and the first region 111 has On the other hand, Au plating is also applied to the second region 112 on the opposite side. The Au plating in the second region 112 is drawn to the second side surface 122 of the package, and further continues to the lower end along the side surface to form the second external connection terminal 142.

  The package 10 is formed by punching a silver-plated copper lead frame, for example, by injection molding a synthetic resin into the lead frame, cutting the outer lead drawn out of the package into an optimum shape, and then packaging the outer lead into a package. It may be bent along the outer side surface and the bottom surface to form external terminals (soldered and connected during surface mounting). In this case, the package is made of polyphthalamide (PPA), polycarbonate resin, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), ABS resin, epoxy resin, phenol resin, acrylic resin, PBT resin, or the like. Then, these melted materials are formed by pouring from a gate on the lower surface side of the package into a mold in which a plurality of lead members are inserted and closed to be cured.

  Further, when the sealing member is filled in the package recess 10a, the thermal expansion of the package is considered in consideration of the adhesion between the package and the sealing member when affected by the heat generated from the elements 16 and 17. A coefficient having a small difference from that of the sealing member is preferable. Moreover, the surface in a recessed part can be embossed, the adhesion area with a sealing member can be increased, and plasma processing can improve adhesiveness with a sealing member.

Further, in order to seal the elements 16 and 17 and the conductive wires 201 to 203 in the recess 10a, the sealing member is not necessarily filled, and an inert gas such as an inorganic binder, N ₂ , or Ar is filled. Alternatively, the inside of the recess may be in a vacuum or a state close thereto.

  (Light-Emitting Element 16) The light-emitting element 16 has a pair of electrodes corresponding to an anode (p electrode) and a cathode (n electrode), and is fixed to the bottom surface 10b of the package recess by die bonding, and the pair of electrodes is a pair of external parts. The connection terminals 141 and 142 are electrically connected. As the light emitting element 16, a blue light emitting element having an emission peak wavelength near 460 nm, a blue-violet light emitting element having an emission peak wavelength near 410 nm, an ultraviolet light emitting element having an emission peak wavelength near 365 nm, or the like is used. can do. The type of the light emitting element 16 is not particularly limited. For example, an example in which a nitride semiconductor such as InN, AlN, GaN, InGaN, AlGaN, or InGaAlN is formed as a light emitting layer on a substrate by MOCVD or the like, an example As an example, an n-type contact layer made of n-type GaN, an n-type cladding layer made of n-type AlGaN, and a p-type contact layer made of p-type GaN are sequentially stacked on a sapphire substrate. . The semiconductor structure includes a homostructure having a MIS junction, a PIN junction, a PN junction, etc., a hetero bond, or a double hetero bond. Various emission wavelengths can be selected depending on the semiconductor material and the mixed crystal ratio. Moreover, it can be set as the single quantum well structure or the multiple quantum well structure which formed the semiconductor active layer in the thin film which produces a quantum effect. The active layer may be doped with donor impurities such as Si and Ge and / or acceptor impurities such as Zn and Mg. The emission wavelength of the light-emitting element can be changed from the ultraviolet region to red by changing the In content of InGaN in the active layer or changing the type of impurities doped in the active layer.

  When realizing a white light emitting device, for example, a blue light emitting element and a YAG phosphor described later as a fluorescent material contained in the light-transmitting coating member (rare earth mainly activated by a lanthanoid element such as Ce) By using a combination with an aluminate phosphor), white light emission can be obtained by color mixture of light emission by the light emitting element and light emission by the YAG phosphor.

  (Protective element 17) The protective element 17 is an element accommodated in the concave portion of the package 10 together with the light emitting element 16, and protects the other light emitting elements 16 from destruction due to overvoltage. The protection element 17 includes not only a semiconductor structure but also a non-semiconductor structure.

  Protection elements that can be used in this embodiment include a Zener diode that is energized when a voltage higher than a specified voltage is applied, a capacitor that absorbs a pulsed voltage, and the like.

  (Sealing member 21) When sealing the elements 16 and 17 in the package recessed part 10a, the translucent sealing member 21, for example, translucent resin, is filled. This translucent resin can protect the light emitting element from external force, moisture, and the like, and when moisture is contained in the translucent resin during the process or during storage, the translucent resin is at a predetermined temperature for a predetermined time or more. By performing baking, the moisture contained in the resin can be released to the outside air, thus preventing adverse effects such as water vapor explosion and color shift caused by peeling between the light emitting element and the sealing member. Can do.

  In addition, the sealing member is required to have high light transmittance in order to efficiently emit light from the light emitting element 16 to the outside. In the structure in which the electrode of the light emitting element and the conductive member in the package are connected by a conductive wire, the sealing member also has a function of protecting the conductive wire. As a material of the translucent resin used as the sealing member, it is preferable to use a transparent resin or glass having excellent weather resistance such as an epoxy resin, a silicone resin, an acrylic resin, or a urea resin. Further, by adding a diffusing agent to the light-transmitting resin, directivity from the light-emitting element can be relaxed and the viewing angle can be increased. Note that a light-emitting device having various emission colors can be provided by including a fluorescent material in the sealing member.

When the sealing member contains a fluorescent substance, the light emitted from the light emitting element is wavelength-converted by mounting a light emitting element and a protective element in the recess and then filling with a translucent resin containing the fluorescent substance. Can be released to the outside. When visible light having a short wavelength with high energy is emitted from the light emitting element, as a fluorescent substance to be contained in the translucent resin, a perylene-type derivative that is an organic phosphor, ZnCdS: Cu, YAG: Ce, Eu, and It is preferable to use an inorganic phosphor such as nitrogen-containing CaO—Al ₂ O ₃ —SiO ₂ activated by Cr.

At this time, when white light is obtained, particularly when a YAG: Ce phosphor is used, yellow light emission that can partially absorb light from the blue light emitting element and become a complementary color is possible depending on the content thereof. By combining with a light emitting element, a white light emitting device can be formed relatively easily and with high reliability. Similarly, when a nitrogen-containing CaO—Al ₂ O ₃ —SiO ₂ phosphor activated with Eu and / or Cr is used, depending on its content, a part of the light from the blue light-emitting element is absorbed to obtain a complementary color. Red light emission becomes possible, and a white light-emitting device can be formed relatively easily and reliably by combination with a blue light-emitting element.

  (Fluorescent substance) A fluorescent substance is excited by absorbing light from a light emitting element, and converts it into light having a wavelength (for example, having a complementary color relationship) different from the emission color of the light emitting element. Phosphors and other phosphors can be used. For example, nitride phosphors / oxynitride phosphors mainly activated by lanthanoid elements such as Eu and Ce, lanthanoid phosphors such as Eu, and alkalis mainly activated by transition metal elements such as Mn Earth halogen apatite phosphor, alkaline earth metal borate halogen phosphor, alkaline earth metal aluminate phosphor, alkaline earth silicate, alkaline earth sulfide, alkaline earth thiogallate, alkaline earth silicon nitride At least selected from organic and organic complexes mainly activated by lanthanoid elements such as germanate or lanthanoid elements such as Ce, rare earth aluminate, rare earth silicate or Eu Any one or more are preferable. These phosphors can use phosphors having emission spectra in yellow, red, green, and blue by the excitation light of the light-emitting element, and emission spectra in yellow, blue-green, orange, etc., which are intermediate colors between them. A phosphor having the following can also be used. By using these phosphors in various combinations, light emitting devices having various emission colors can be manufactured.

For example, when a GaN-based compound semiconductor that emits blue light is used to irradiate a fluorescent material of Y ₃ Al ₅ O ₁₂ : Ce or (Y _0.8 Gd _0.2 ) ₃ Al ₅ O ₁₂ : Ce and perform wavelength conversion, light emission occurs. A light-emitting device that emits white light by a mixed color of light from an element and light from a fluorescent material can be provided.

For example, CaSi ₂ O ₂ N ₂ : Eu or SrSi ₂ O ₂ N ₂ : Eu that emits light from green to yellow, and (Sr, Ca) ₅ (PO ₄ ) ₃ Cl: Eu that emits blue light as a phosphor. By using the fluorescent material 140 made of (Ca, Sr) ₂ Si ₅ N ₈ : Eu that emits red light, a light emitting device that emits white light with good color rendering can be provided. Since the three primary colors red, blue and green are used, desired white light can be realized only by changing the blend ratio of the first phosphor and the second phosphor.

(Conductive wires 201 to 203) As the conductive wires, those having good ohmic properties, mechanical connectivity, electrical conductivity and thermal conductivity with the electrodes of the light emitting element are required. The thermal conductivity, preferably ^{0.01cal / (S) (cm 2} ) (℃ / cm) or higher, more preferably is ^{0.5cal / (S) (cm 2} ) (℃ / cm) or more. In consideration of workability and the like, the diameter of the conductive wire is preferably 10 μm or more and 45 μm or less. Specific examples of such conductive wires include wires using metals such as gold, copper, platinum, and aluminum, and alloys thereof. Such a conductive wire can be easily bonded and connected between the light emitting element and the conductive member inside the package by a wire bonding apparatus.

  Hereinafter, a plurality of examples of the light emitting device of the present invention will be described.

  Example 1 FIGS. 1 to 6 schematically show a light-emitting device according to Example 1. FIG. This light-emitting device has the same configuration as that described above in the first embodiment. As the main configuration, the package 10, the light-emitting element 16, the protective element 17, the conductive wires 201 to 203, and the translucent sealing member 21 are included. The light emitting element 16 is bonded by an epoxy resin 18, and the protective element 17 is bonded by an Ag paste 19.

  For example, four ceramic plates are stacked in the package 10, and Au plating is formed on one surface of the two ceramic plates, and the Au plating is formed between a pair of opposing side surfaces 121, The structure is sintered in a state of being stacked so as to be pulled out to 122. Here, each ceramic plate is configured such that a recess 10a for element storage exists on the upper surface of the package 10 and a step portion 11 exists on the outer peripheral portion of the bottom surface 10b of the recess.

  For example, the entire surface of the recess bottom surface 10b is plated with Au as the conductive member 131. The Au plating is drawn to the first side surface 121 of the package, and further continues to the lower end along the side surface. External connection terminal 141 is provided. Further, on the upper surface of the step portion 11, Au plating is applied as the conductive member 132 so as to continue from the first region 111 on the first external connection terminal 141 side to the first external connection terminal 141. Furthermore, Au plating is drawn out as a conductive member 133 from the second region 112 opposite to the first region 111 to the second side surface 122 of the package, and further continues to the lower end along the side surface. External connection terminal 142.

  A protective element 17 formed on a p-substrate is used, and its p-side electrode surface is bonded with an Ag paste 19. The light emitting element 16 is disposed such that the n-side electrode 16n is positioned on the first region 111 side and the p-side electrode 16n is positioned on the second region 112 side. The first conductive wire 201 is bonded to the n-side electrode 16n of the light-emitting element 16 and the Au plating surface of the first region 111 on the upper surface of the step portion. The second conductive wire 202 is bonded to the Au plated surface of the second region 112, and the third conductive wire is connected to the n-side electrode on the upper surface of the protection element 17 and the Au plated surface of the second region 112. 203 is connected by bonding. As a result, the n-side electrode 16n of the light-emitting element 16 and the p-side electrode 17p of the protection element 17 are commonly connected to the first external connection terminal region 141, and the light-emitting element 16 of the light-emitting element 16 is connected to the second external connection terminal 142. The p-side electrode 16p and the n-side electrode 17n of the protection element 17 are connected in common. That is, the protection element 17 is electrically connected in antiparallel to the light emitting element 16.

  As described above, the protective element 17 formed on the p substrate can be realized in a smaller size than the protective element formed on the n substrate described in the conventional example, and the package concave bottom surface 10b is a conventional product (the concave bottom surface). 2 elements (light emitting element and protective element) can be easily mounted on the same plane. In this case, the polarity identification mark 15 on the upper end surface of the package has a meaning as a cathode mark indicating that the first external connection terminal 141 of the first side surface 121 of the package is the n-side electrode side of the LED device. Have. This has the advantage of having the same meaning as the polarity identification attached to the upper end surface of the package of the conventional product (the 2nd bonding position exists on the same plane as the device).

  Note that the second region 112 of the stepped portion is formed so as to swell toward the inside of the recess, and has a larger area than the first region 111. In addition, the stepped portion 22 is configured so that the opening size on the front end side is narrowed stepwise in the vicinity of the opening on the side wall of the recess 10a.

  According to Example 1, the effects described above in the first embodiment can be obtained. In addition, since the area of the second region 112 is larger than that of the first region 111, 2nd bonding at two locations can be easily performed. Further, since the step portion 22 is provided in the vicinity of the opening of the recess side wall, even if the adhesiveness between the translucent sealing member 21 and the package is lowered, the penetration in the recess 10a is received when a strong impact is received. It becomes possible to act as a stopper portion for preventing the optical sealing member 21 from jumping to the tip side.

  (Example 2) The light-emitting device of Example 2 is different from the light-emitting device of Example 1 described above in that a protective element 17 formed on an n substrate is used. The configuration is the same as that described above in the embodiment. The protection element 17 formed on the n substrate has an n-side electrode surface joined by an Ag paste 19. The light emitting element 16 is disposed such that the p-side electrode 16p is positioned on the first region 111 side and the n-side electrode 16n is positioned on the second region 112 side. A first conductive wire 201 is bonded to the p-side electrode 16p of the light-emitting element 16 and the Au plating surface of the first region 111 on the upper surface of the step portion, and the n-side electrode 16n of the light-emitting element 16 and the upper surface of the step portion are connected. A second conductive wire 202 is bonded to the Au plated surface of the second region 112, and the third conductive material is connected to the p-side electrode on the upper surface of the protection element 17 and the Au plated surface of the second region 112. The wire 203 is connected by bonding. Thereby, the p-side electrode 16p of the light emitting element 16 and the n-side electrode of the protection element 17 are commonly connected to the first external connection terminal region 141, and the n external electrode of the light emitting element 16 is connected to the second external connection terminal region 142. The side electrode 16n and the p-side electrode of the protection element 17 are connected in common. That is, the protection element 17 is electrically connected in antiparallel to the light emitting element 16.

  According to Example 2, the effects described above in the first embodiment can be obtained. Moreover, the protective element formed on the n substrate can be obtained as a standard product at low cost, and the manufacturing cost of the light emitting device can be suppressed.

  The light-emitting device of the present invention can be used as a light source for various optical devices such as signal lights, illuminations, displays, indicators, liquid crystal projectors, and liquid crystal backlights. It is suitable for.

1 is a partially transparent perspective view schematically showing an example of a surface-mount package type LED device according to a first embodiment of the present invention. FIG. 2 is a partially transparent plan view schematically showing the LED device of FIG. 1. Sectional drawing which shows schematically the cross-section of the arrow direction in alignment with the AA in FIG. Sectional drawing which shows schematically the cross-section of the arrow direction which follows the BB line in FIG. Sectional drawing which shows schematically the cross-section of the arrow direction which follows the CC line | wire in FIG. Sectional drawing which shows schematically the cross-section of the arrow direction which follows the DD line | wire in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Package, 10a ... Concave part, 10b ... Concave bottom face, 11 ... Step part, 111 ... 1st area | region, 112 ... 2nd area | region, 121 ... 1st side surface of a package, 122 ... 2nd side surface of a package, 131: First conductive member, 132: Second conductive member, 133: Third conductive member, 141: First external connection terminal, 142: Second external connection terminal, 15: Polarity identification mark, 16: Light emitting element, 16n ... n-side electrode, 16p ... p-side electrode, 17 ... protective element, 17n ... n-side electrode, 18 ... epoxy resin, 19 ... conductive paste (Ag paste), 201-203 ... conductive wire, 21 ... Translucent sealing member.

Claims (6)

A light emitting device of a surface mount package type in which a light emitting element and a protective element are joined on the same plane at a bottom surface in a recess formed on the upper surface of the package, and the light emitting element and the protective element are connected in reverse parallel to each other,
A stepped portion provided higher than the light emitting element or the protective element at the periphery of the bottom surface in the recess;
A first conductive member provided at least on a joint of the protection element on the bottom surface;
A second conductive member provided in a first region near the top surface of the light emitting element on the top surface of the stepped portion;
A third conductive member provided in a second region near the top surface of the light emitting element and near the top surface of the protection element on the top surface of the stepped portion;
A first conductive wire bonded and connected between a first electrode on an upper surface of the light emitting element and a second conductive member in the first region;
A second conductive wire bonded and connected between the second electrode on the upper surface of the light emitting element and the third conductive member in the second region;
A third conductive wire bonded and connected between the electrode on the upper surface of the protection element and the third conductive member of the second region;
The second region of the step portion is formed so as to swell toward the inside of the recess, and the second conductive wire and the third conductive wire swell toward the inside of the recess. A light-emitting device, wherein the light-emitting device is bonded to the third conductive member in the upper surface region of the formed portion . An insulating package having a recess for accommodating a chip on the upper surface;
A stepped portion provided higher than a light emitting element or a protective element mounted on the same plane on the bottom surface at the periphery of the bottom surface in the recess,
A first conductive member extending from at least a part of the upper surface of the bottom surface through the package side wall to the first side surface of the package;
A second conductive member drawn out from the first region on the top surface of the stepped portion so as to penetrate the package side wall and continue to the first conductive member on the first side surface;
A third conductive member drawn from the second region electrically insulated from the first region on the upper surface of the stepped portion through the package side wall to the second side surface of the package;
The light emitting element bonded face-up on the bottom surface in the recess;
The protective element in which a lower surface side electrode is bonded to the first conductive member by a conductive paste in the vicinity of the second region on the bottom surface;
A first conductive wire bonded and connected between a first electrode on an upper surface of the light emitting element and a second conductive member on the first region;
The second conductive wire bonded between the second electrode on the upper surface of the light emitting element and the third conductive member on the second region near the upper surface of the light emitting element on the upper surface of the stepped portion. When,
A third conductive wire bonded and connected between the upper surface side electrode of the protection element and a third conductive member on the second region in the vicinity of the upper surface of the protection element on the upper surface of the step ;
A translucent member that seals each light emitting element, the protection element, and each conductive wire in the recess;
The light emitting element and the protection element are connected in reverse parallel to each other , and the second region of the step portion is formed to swell toward the inside of the recess, and the second conductive wire and the second conductive wire 3. The light emitting device according to claim 3, wherein the conductive wire 3 is bonded to a third conductive member in an upper surface region of a portion formed so as to swell toward the inside of the recess .   3. The light emitting device according to claim 1, wherein a distance from an upper surface side electrode of the protection element to the second region is equal to or less than a distance from an upper surface side electrode of the light emitting element to the second region. apparatus.   The protective element has a p-side electrode surface bonded to a bottom surface in the recess, and the light-emitting element has the n-side electrode on the first region side and the p-side electrode on the second region side. A first conductive wire is bonded between the n-side electrode of the light-emitting element and the conductive member on the first region, and the p-side electrode of the light-emitting element and the The second conductive wire is bonded to the conductive member on the second region, and the third electrode is connected between the n-side electrode of the protection element and the conductive member on the second region. The light-emitting device according to claim 1, wherein the conductive wires are connected by bonding.   The protective element has an n-side electrode surface bonded to the bottom surface of the recess, and the light-emitting element has the p-side electrode located on the first region side and the n-side electrode located on the second region side. A first conductive wire is bonded to the p-side electrode of the light-emitting element and the conductive member on the first region, and the n-side electrode of the light-emitting element and the second region are The second conductive wire is bonded to the conductive member, and the third conductive wire is bonded to the p-side electrode of the protection element and the conductive member on the second region. The light emitting device according to claim 1 or 2. The first conductive member or the second conductive member is metal-plated, and is further drawn out as a first external connection terminal to the lower end of the first side surface,
6. The third conductive member according to claim 1, wherein the third conductive member is made of metal plating, and is drawn out as a second external connection terminal to a lower end portion of the second side surface. Light-emitting device.

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