JP4742772B2 - Light emitting device - Google Patents

Description

  The present invention relates to a light emitting device that emits light from an LED chip.

Conventionally, as disclosed in Patent Document 1, this type of light emitting device includes an LED chip, a substrate (mounting substrate) on which the LED chip is mounted in a recess, an LED chip, and a bonding connected to the LED chip. And a sealing portion made of a transparent resin (for example, epoxy resin or silicone resin) filled so as to seal the wire. In the light emitting device disclosed in Patent Document 1, the light emitted from the LED chip is transmitted through the sealing portion to irradiate the outside.
JP 2001-148514 A

  However, in the conventional light emitting device, since the LED chip is mounted in the depression of the mounting substrate, most of the light emitted from the side surface of the LED chip is blocked by the side surface of the depression of the mounting substrate and radiates the outside. There was a problem that I could not.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a light-emitting device that can efficiently extract light emitted from an LED chip.

The invention according to claim 1 is an LED chip that emits light from one surface and a side surface extending to the one surface, and the LED chip on the other surface facing the one surface of the LED chip. convex sealing portion, on the light incident surface the LED chip side having but a mounting board mounted, the elastic with sealing the bonding wires connected are formed on the LED chip and the LED chip by a transparent resin A lens that is formed in a curved surface and has a light emitting surface formed in a convex curved surface and is placed on the sealing portion, and an emission color of the LED chip excited by light emitted from the LED chip A dome that includes phosphors that emit light of different colors and that covers the lens and the sealing portion, and is disposed in a form in which an air layer is formed between the light emitting surface of the lens and the sealing portion. Comprising of a color conversion member, the LED chip is projected to the lens side with respect to the lens surface facing in the mounting substrate, the side surface is opposed to the color conversion member through the sealing portion It is characterized by.

  In this configuration, the light emitted from one surface of the LED chip in a parallel direction or the light emitted from the side surface in the vertical direction can pass through the sealing portion without being blocked by the mounting substrate and irradiate the outside. Since it can do, the light radiated | emitted from the LED chip can be taken out efficiently. Since the light emitted from the LED chip enters the lens from the light incident surface having a convex curved surface, the directivity can be improved. Moreover, since the extraction efficiency of the mixed color light of the light emitted from the LED chip and the light emitted from the phosphor of the color conversion member can be increased, the light output can be further improved. Since the color conversion member is not in close contact with the lens, it is possible to suppress a decrease in yield due to the dimensional accuracy and positioning accuracy of the color conversion member, and when an external force acts on the color conversion member, It is possible to suppress the generated stress from being transmitted to the LED chip through the lens and the sealing portion. Moreover, it is possible to make it difficult for moisture in the external atmosphere to reach the LED chip.

  According to the present invention, the light emitted from the LED chip can be efficiently extracted.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing the configuration of the light emitting device of this embodiment. FIG. 2 is a top view illustrating a configuration of a main part of the light emitting device according to the present embodiment. FIG. 3 is an exploded perspective view showing the configuration of the light emitting device of this embodiment. FIG. 4 is a perspective view illustrating a method for manufacturing the light emitting device of this embodiment.

  First, the basic configuration of this embodiment will be described. As shown in FIG. 1, the light emitting device of the present embodiment includes an LED chip 1, a mounting substrate 2, a sealing portion 3, a lens 4, and a color conversion member 5.

  The LED chip 1 is a GaN-based blue LED chip that emits blue light, and includes a conductive substrate 10 and a light emitting unit 11. The conductive substrate 10 is made of an n-type SiC substrate having a lattice constant or crystal structure close to that of GaN and having conductivity as a crystal growth substrate compared to a sapphire substrate. The conductive substrate 10 is mounted on a metal plate 20 to be described later by bonding to the submount member 12 on a lower surface 100 facing the upper surface 110 of the light emitting unit 11 to be described later. On the other hand, the light emitting unit 11 is formed of a GaN-based compound semiconductor material on the upper surface 101 side of the conductive substrate 10 and includes, for example, a stacked structure unit having a double hetero structure, and is grown by an epitaxial growth method (for example, MOVPE method). It is a thing. The light emitting unit 11 emits blue light from the upper surface 110 and a plurality of side surfaces 111, 111 extending on the upper surface 110. A cathode electrode (n electrode) (not shown), which is a cathode side electrode, is formed on the lower surface 100 of the conductive substrate 10, and an anode side electrode is formed on the upper surface 110 of the light emitting unit 11. An anode electrode (p electrode) (not shown) is formed. The cathode electrode and the anode electrode are composed of a laminated film of a Ni film and an Au film, but the material of the cathode electrode and the anode electrode is not particularly limited, and a material capable of obtaining good ohmic characteristics For example, Al may be used.

  The submount member 12 is formed in a rectangular plate shape having a size larger than the chip size of the LED chip 1, and the LED chip 1 is caused by a difference in linear expansion coefficient between the LED chip 1 and the metal plate 20. Relieve stress acting on Further, the submount member 12 has a heat conduction function for transferring heat generated in the LED chip 1 to a range wider than the chip size of the LED chip 1 in the metal plate 20. In this embodiment, AlN having a relatively high thermal conductivity and insulating properties is employed as the material of the submount member 12, but the material of the submount member 12 is not limited to AlN, and the linear expansion coefficient is conductive. Any material that is relatively close to 6H—SiC that is a material of the substrate 10 and that has a relatively high thermal conductivity may be used. For example, composite SiC, Si, or the like may be employed. Further, the submount member 12 includes a reflective film (for example, a laminated film of a Ni film and an Ag film) (not shown) that reflects light emitted from the LED chip 1 around the electrode pattern.

  In the LED chip 1, as shown in FIG. 2, a cathode electrode (not shown) is provided on the surface 120 of the submount member 12, and an electrode pattern (not shown) connected to the cathode electrode, and a fine metal wire (for example, a gold wire) The lead wire is electrically connected to one lead pattern 23 (lower side in FIG. 2) via a bonding wire 13 such as a thin wire or an aluminum thin wire, and an anode electrode (not shown) is connected to the other lead via the bonding wire 13. It is electrically connected to the pattern 23 (upper side in FIG. 2). The LED chip 1 and the submount member 12 may be bonded using, for example, solder such as SnPb, AuSn, SnAgCu, or silver paste, but may be bonded using lead-free solder such as AuSn, SnAgCu. Is preferred.

  Further, as shown in FIG. 1, by bonding the LED chip 1 to the submount member 12, the LED chip 1 is a surface 210 that is a surface facing the lens 4 in the insulating base material 21 of the mounting substrate 2 described later. Is arranged so as to protrude toward the lens 4 (upper side in FIG. 1).

  The mounting substrate 2 includes a metal plate 20 and an insulating base material 21 that are stacked. The metal plate 20 and the insulating base material 21 are fixed by a fixing material 22 made of a sheet-like adhesive film having insulating properties. Although Cu is employed as the material of the metal plate 20, any metal material having a relatively high thermal conductivity may be used, and not only Cu but Al or the like may be employed. Further, the submount member 12 on which the LED chip 1 is mounted is mounted on the metal plate 20. On the other hand, the insulating substrate 21 is, for example, a glass epoxy substrate. A pair of lead patterns 23 that are electrically connected to both electrodes (not shown) of the LED chip 1 are provided on the surface 210 of the insulating base material 21. Each lead pattern 23 is a laminated film of a Ni film and an Au film, and portions not covered by the color conversion member 5 are outer lead portions 230 and 230 (see FIG. 2). Further, the surface 210 of the insulating substrate 21 is provided with a window hole 24 at a portion corresponding to the LED chip 1, and heat generated in the LED chip 1 is transmitted to the metal plate 20 without passing through the insulating substrate 21. It can be heated.

  The sealing part 3 has elasticity and is formed by filling (potting) a transparent resin such as a silicone resin, for example, and seals the LED chip 1 and the bonding wires 13 and 13. In the present embodiment, the sealing portion 3 is formed by filling a molding resin 90, 91 (see FIG. 4) with a transparent resin and thermosetting. In addition, as the sealing part 3, it is not limited to a silicone resin, You may use an acrylic resin etc. Since the silicone resin has higher heat resistance and thermal conductivity than the epoxy resin and acrylic resin, the silicone resin is not deformed even at a high temperature, and the heat radiation effect for the heat from the LED chip 1 can be enhanced.

  The lens 4 is a molded product such as a silicone resin, for example, and has a light incident surface 40 formed in a convex curve shape on the LED chip 1 side (lower side in FIG. 1) and a light emission surface 41 formed in a convex curve shape. And is disposed so as to overlap the sealing portion 3. That is, the lens 4 is a biconvex lens. The lens 4 is disposed so that the optical axis is located on the center line of the light emitting unit 11 along the thickness direction of the LED chip 1. As described above, since the light exit surface 41 is formed in a convex curved surface, the lens 4 does not totally reflect the light incident from the light entrance surface 40 at the boundary between the light exit surface 41 and the air layer 6. It has become. The lens 4 has the same refractive index as that of the sealing portion 3, but is not limited to a silicone resin molded product, and may be, for example, an acrylic resin molded product.

  The color conversion member 5 is a molded product formed in a dome shape by a mixture of a transparent material and a phosphor, covers the sealing portion 3 and the lens 4, and includes the sealing portion 3 and the light emitting surface 41. The air layer 6 is disposed between the two. The color conversion member 5 has an inner surface 50 formed in a shape along the light emitting surface 41 of the lens 4. Therefore, the distance between the light emitting surface 41 and the inner surface 50 of the color conversion member 5 in the normal direction is a substantially constant value regardless of the position of the light emitting surface 41 of the lens 4. Further, the color conversion member 5 is formed so that the thickness along the normal direction is uniform regardless of the position. Furthermore, the color conversion member 5 is bonded to the insulating base 21 of the mounting substrate 2 at the periphery of the opening using, for example, an adhesive (for example, silicone resin, epoxy resin, or the like). The transparent material is, for example, a silicone resin. The transparent material is not limited to a silicone resin, and for example, an acrylic resin, an epoxy resin, or glass may be employed. On the other hand, the phosphor is in the form of particles and is excited by blue light emitted from the LED chip 1 to emit broad yellow light having a color different from the emission color of the LED chip 1. The phosphor is not limited to the yellow phosphor, and may be a red phosphor and a green phosphor, for example.

  Since such a color conversion member 5 is not in close contact with the lens 4, it suppresses a decrease in yield due to dimensional accuracy and positioning accuracy. Further, when an external force is applied to the color conversion member 5, the stress generated in the color conversion member 5 is suppressed from being transmitted to the LED chip 1 through the lens 4 and the sealing portion 3. Furthermore, the moisture in the external atmosphere is difficult to reach the LED chip 1.

  Such a light emitting device of the present embodiment is mounted on an instrument body 8 made of metal (for example, a metal having high thermal conductivity such as Al, Cu) via an insulating layer 7 such as a green sheet, The thermal resistance from the LED chip 1 to the fixture body 8 can be reduced, heat dissipation is improved, and the temperature rise of the junction temperature of the LED chip 1 can be suppressed, so that the input power can be increased and the light High output can be achieved.

  Next, the manufacturing method of the light-emitting device of this embodiment is demonstrated using FIG. In FIG. 3, each component before manufacture is shown. FIG. 4 shows a range A in FIG. First, as shown in FIG. 4 (a), the LED chip 1 is mounted on the mounting substrate 2 in which the metal plate 20 and the insulating base material 21 are laminated via the submount member 12, and the bonding wires 13, 13 are mounted. Bonding (see FIG. 2) is performed (first step). 3 and 4, illustration of the bonding wires 13 and 13 is omitted. After the first step, as shown in FIG. 4 (b), the insulating base material is formed such that a pair of semi-cylindrical molding dies 90, 91 form a cylindrical frame with both molding dies 90, 91. The LED chip 1 and the bonding wires 13 and 13 are attached to the surface 210 of the substrate 21 (second step). After the second step, the transparent resin 92 is poured into the molds 90 and 91 from a container 93 containing a liquid transparent resin (silicone resin) 92 (third step). Then, as shown in FIG. 4 (c), the lens 4 is prepared in a state where the transparent resin 92 is filled inside the molding dies 90, 91. As shown in FIG. 4 (d), the lens 4 is prepared. Is placed on the transparent resin 92, and then the transparent resin 92 is thermally cured to form the sealing portion 3 and to fix the sealing portion 3 and the lens 4 (fourth step). Subsequently, as shown in FIG. 4E, the molding dies 90 and 91 are released (fifth step). Finally, the color conversion member 5 shown in FIG. 3 is fixed to the surface 210 of the insulating substrate 21 using an adhesive or the like (sixth step).

  Next, the optical path of the light emitted from the LED chip 1 in the light emitting device of this embodiment will be described with reference to FIG. First, blue light emitted from the upper surface 110 of the light emitting unit 11 of the LED chip 1 will be described. The blue light emitted from the upper surface 110 of the light emitting unit 11 in the vertical direction (upward in FIG. 1) sequentially propagates through the sealing unit 3, the lens 4, and the air layer 6 to reach the color conversion member 5, and The blue light emitted from the upper surface 110 of the light emitting unit 11 in the parallel direction (the left-right direction in FIG. 1) propagates in order through the sealing unit 3 and the air layer 6 and reaches the color conversion member 5. Subsequently, the phosphor is excited by the blue light reaching the color conversion member 5 to emit yellow light. Finally, white light is emitted from the outer surface 51 of the color conversion member 5 by a combination of the blue light emitted from the LED chip 1 and the yellow light emitted from the phosphor of the color conversion member 5.

  On the other hand, the blue light radiated | emitted from the side surfaces 111 and 111 of the light emission part 11 of LED chip 1 is demonstrated. Blue light radiated in the vertical direction (left and right direction in FIG. 1) from the side surfaces 111 and 111 of the light emitting unit 11 sequentially propagates through the sealing unit 3 and the air layer 6 to reach the color conversion member 5 and emits the light. Blue light radiated in the parallel direction (upward in FIG. 1) from the side surfaces 111 and 111 of the part 11 propagates in order through the sealing part 3, the lens 4 and the air layer 6 and reaches the color conversion member 5. Subsequently, as in the case where the light is emitted from the upper surface 110 of the light emitting unit 11, the phosphor is excited by the blue light reaching the color conversion member 5 to emit yellow light, and the combination of the blue light and the yellow light. Thus, white light is emitted from the outer surface 51 of the color conversion member 5.

  From the above, not only the blue light emitted from the light emitting part 11 of the LED chip 1 in the upward direction of FIG. 1 but also the blue light emitted from the light emitting part 11 of the LED chip 1 in the horizontal direction of FIG. Without being blocked, the color conversion member 5 can be reached, and white light can be emitted to the outside. Even if the phosphor of the color conversion member 5 is a red phosphor and a green phosphor, white light can be emitted in the same manner.

  Next, the flow of heat from the LED chip 1 in the light emitting device of this embodiment will be described. First, part of the heat from the LED chip 1 is conducted to the metal plate 20 via the submount member 12. Subsequently, the metal plate 20 having high thermal conductivity performs heat dissipation. On the other hand, the remaining heat from the LED chip 1 is conducted to the sealing portion 3, and heat is released by the sealing portion 3.

  From the above, it is possible to prevent the temperatures of the LED chip 1 and the entire light emitting device from becoming abnormally high.

  As described above, according to the present embodiment, the light emitted from the upper surface 110 of the light emitting unit 11 of the LED chip 1 in the parallel direction (left and right direction in FIG. 1) and the vertical direction from the side surfaces 111 and 111 (left and right direction in FIG. 1). Since the emitted light can pass through the sealing portion 3 without being blocked by the mounting substrate 2 and can be irradiated to the outside, the light emitted from the LED chip 1 can be efficiently extracted.

  Since light emitted from the LED chip 1 enters the lens 4 from the light incident surface 40 having a convex curved surface, directivity can be improved. Moreover, since the extraction efficiency of the white light which is the mixed color light of the blue light radiated | emitted from LED chip 1 and the yellow light radiated | emitted from the fluorescent substance of the color conversion member 5 can be improved, the improvement of light output is further improved. Can be planned.

  Since the color conversion member 5 is not in close contact with the lens 4, it is possible to suppress a decrease in yield due to the dimensional accuracy and positioning accuracy of the color conversion member 5, and when an external force acts on the color conversion member 5, It can suppress that the stress which generate | occur | produced in the color conversion member 5 is transmitted to the LED chip 1 through the lens 4 and the sealing part 3. FIG. Moreover, it is possible to make it difficult for moisture in the external atmosphere to reach the LED chip 1.

  As a modification of the present embodiment, the LED chip may be mounted on the metal plate such that the light emitting unit is closer to the metal plate than the conductive substrate. Even in such a configuration, when the conductive substrate and the light emitting unit have the same refractive index, the light extraction loss does not become too large, and the same operation as in the present embodiment can be performed. it can.

It is sectional drawing which shows the structure of the light-emitting device of embodiment by this invention. It is a top view which shows the principal part structure of a light-emitting device same as the above. It is a disassembled perspective view which shows the structure of a light-emitting device same as the above. It is a perspective view explaining the manufacturing method of a light-emitting device same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 LED chip 11 Light emission part 110 Upper surface 111 Side surface 2 Mounting board 21 Insulating base material 210 Surface 3 Sealing part 4 Lens 5 Color conversion member 6 Air layer

Claims (1)

An LED chip that emits light from one surface and a side surface extending to the one surface;
A mounting substrate on which the LED chip is mounted on the other surface facing the one surface of the LED chip;
And a sealing portion having elasticity with formed by a transparent resin sealing the bonding wires connected to the LED chip and the LED chip,
A light incident surface is formed in a convex curve shape on the LED chip side and a light emission surface is formed in a convex curve shape and is disposed on the sealing portion; and
The phosphor includes a phosphor that is excited by light emitted from the LED chip and emits light of a color different from the emission color of the LED chip, covers the lens and the sealing portion, and the light emitting surface of the lens A dome-shaped color conversion member disposed in a form in which an air layer is formed between the sealing portion and
The LED chip, the light emitting device, characterized in that the said projecting lens side with respect to the lens surface facing the mounting board, the side surface is opposed to the color conversion member through the sealing portion.

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