JP2013183124A - Semiconductor light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED device which enables a phosphor having characteristics deteriorated at high temperatures to be used and concurrently enables an easy manufacturing and an easy attachment to another device even when a number of LED dies are mounted on a circuit board.SOLUTION: A metal frame 21 covers a part of an upper surface of a circuit board 22 and has attachment parts 21a for attaching the circuit board 22 to another device. The metal frame 21 opens at a mounting region of LED dies 26 and a frame part 21c fixes an end part of a phosphor plate 23. As a result, the temperature rise of a phosphor included in the phosphor plate 23 becomes small. Concurrently, as the metal frame 21 is formed separately from the circuit board 22, a large number of the metal frames 21 are manufactured in a short time and the attachment part 21a is formed when the metal frame 21 is manufactured.

Description

  The present invention relates to a semiconductor light emitting device that converts the wavelength of light emitted from a semiconductor light emitting element using a phosphor.

  A semiconductor light emitting device (hereinafter referred to as an LED die unless otherwise specified) cut from a wafer is mounted on a lead frame or a circuit board and covered with a translucent member such as resin or glass and packaged (hereinafter referred to as a light emitting device). Unless otherwise specified, it is called an LED device). Although this LED device takes various forms depending on the application, in order to obtain high-output light emission, a large number of LED dies may be mounted on a single circuit board.

  As an example of such an LED device, FIG. 3 of Patent Document 1 shows an appearance of a light emitting device 70 (LED device), and FIG. 3 and 6 of Patent Document 1 are shown again in FIGS. 7 and 8, and this light emitting device will be described. 7 is a perspective view showing a conventional light-emitting device 70, and FIG. 8 is a cross-sectional view taken along the line XX in FIG. As shown in FIG. 7, the light emitting device 70 includes a substrate 10 (circuit board), a plurality of light emitting elements 71 (LED dies), and bonding wires 72 (see FIG. 8) connected to the electrodes of the respective light emitting elements 71. A frame member 73 and a sealing member 74 are provided. The substrate 10 is formed in a substantially rectangular shape, and uses aluminum having excellent thermal conductivity and excellent heat dissipation as a base plate in order to enhance the heat dissipation of each light emitting element 71. The substrate 10 is provided with a power supply connector 19 on its upper surface, and the power supply connector 19 is connected to the power supply terminal portions 16 and 17.

  As shown in FIG. 8, the substrate 10 has an insulating layer 12 laminated on one surface of an aluminum base plate 11. The insulating layer 12 is an electrically insulating organic material such as an epoxy resin. The light emitting element 71 is die-bonded on the reflective layer 13 and is electrically connected by a bonding wire 72 made of a gold (Au) fine wire. In each light emitting element row (see FIG. 7), the light emitting elements 71 are connected in series in the direction in which the row extends, and the respective light emitting element rows are connected in parallel. In this way, the light emitting device 70 prevents the light emission of the entire light emitting device 70 from being stopped even if any one of the light emitting element rows cannot emit light due to bonding failure or the like. ing.

  The frame member 73 surrounding the mounting region of the light emitting element 71 is obtained by applying uncured silicone resin on the substrate 10 in a frame shape by a dispenser and then heating and curing. The sealing member 74 is a translucent synthetic resin such as a transparent silicone resin containing an appropriate amount of phosphor, and is filled inside the frame member 73, and includes the reflective layer 13, the positive electrode side power supply conductor 14, and the negative electrode side power supply. The conductor 15, the bonding wire 72, the connecting portion of the bonding wire 72, and each light emitting element 71 are sealed. The reflective layer 13, the positive electrode side power supply conductor 14, and the negative electrode side power supply conductor 15 have a three-layer structure. On the insulating layer 12, a copper pattern as the first layer 18a and nickel (Ni ) Layer and a silver (Ag) layer as the third layer 18c are laminated.

JP 2011-71242 A (FIGS. 3 and 6)

In the LED device (light emitting device 70) shown in FIGS. 7 and 8, the phosphor held in the sealing resin 74 becomes high temperature due to the heat generated by the LED die (light emitting element 71). However, some phosphors have excellent properties such as wavelength conversion efficiency at room temperature, but degrade the properties at high temperatures. For this reason, the LED device (light emitting device 70) shown in FIGS. 7 and 8 limits the phosphors that can be used.

  Each LED device (light emitting device 70) must be coated with the frame member 73 one by one. In order to shorten the manufacturing time for mass production, a large number of dispensers, which are high-precision coating apparatuses, must be prepared, resulting in an increase in manufacturing cost.

  Although not specified in Patent Document 1, it is estimated from FIG. 7 that the LED device (light emitting device 70) fixes the notch portion of the circuit board (substrate 10) with screws or pins when the LED device (light emitting device 70) is attached to the lighting device. Is done. However, it is not preferable to provide a notch in the circuit board because an additional process is required. In addition, when the substrate base material is ceramic, it may be cracked if screwed.

  Therefore, the present invention has been made in view of the above problems, and can be used even with a phosphor that has good characteristics at room temperature and deteriorates characteristics at high temperature, and can be manufactured and attached to other devices at the same time. An object of the present invention is to provide a semiconductor light emitting device that can be easily manufactured.

In order to solve the above problems, a semiconductor light emitting device of the present invention is a semiconductor light emitting device comprising a circuit board, a plurality of semiconductor light emitting elements mounted on the circuit board, and a phosphor that converts the wavelength of light emitted from the semiconductor light emitting element. ,
A frame that covers a part of the upper surface of the circuit board, has a mounting region for the semiconductor light emitting element, and has an attachment portion for attachment to another device;
And a fluorescent plate that is fixed to the frame, includes the phosphor, and covers an upper portion of the semiconductor light emitting element.

  In the semiconductor light emitting device of the present invention, since the fluorescent plate is fixed to the frame and the fluorescent plate and the semiconductor light emitting element are not adjacent to each other, even when the semiconductor light emitting element emits light and is at a high temperature, Temperature rise is small. The frame that supports the fluorescent plate is separate from the circuit board, and can be manufactured in large quantities in a short time because it can be made of a general material such as plastic or metal. Furthermore, an attachment part for attaching to another device is included in the frame, and this attachment part can be formed in the manufacturing process of the frame.

  The frame may be made of metal.

  The fluorescent plate may be bonded to the frame.

  Two attachment portions of the frame may be provided.

  The semiconductor light emitting element may be covered with the transparent light transmissive member.

  The translucent member may cover the semiconductor light emitting element in a dome shape.

  The semiconductor light emitting element may be flip-chip mounted on the circuit board.

  Each of the semiconductor light emitting elements may be individually covered with the light transmissive member.

  The translucent member may be applied to the upper surface of the semiconductor light emitting element.

  The semiconductor light emitting element may include a reflecting member on a side surface.

  As described above, in the semiconductor light emitting device of the present invention, the frame body that supports the fluorescent plate covers a part of the circuit board, and at the same time, has a mounting portion to another device. Even if the semiconductor light emitting element generates heat, the fluorescent plate supported by the frame does not reach a high temperature. Therefore, it is possible to use a phosphor that has good characteristics at room temperature and deteriorates characteristics at high temperature. In addition, the frame body is separate from the circuit board and can be formed of a general member, so that it can be manufactured in large quantities in a short time. Furthermore, an attachment part for fixing to another apparatus at the time of manufacturing the frame can be formed. That is, the semiconductor light-emitting device of the present invention can be used even with a phosphor that has good characteristics at normal temperature and deteriorates characteristics at high temperature, and at the same time, it can be easily manufactured and attached to other devices.

The external view of the LED device in 1st Embodiment of this invention. Sectional drawing of the LED apparatus shown in FIG. The top view of the state which removed the fluorescent plate from the LED apparatus shown in FIG. Sectional drawing of the translucent member contained in the LED device shown in FIG. The top view of the LED device in 2nd Embodiment of this invention. Sectional drawing of the LED apparatus in 3rd Embodiment of this invention. The perspective view which shows the conventional LED device. Sectional drawing of the LED apparatus shown in FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted. For the sake of explanation, the scale of the members is changed as appropriate. Furthermore, the relationship with the invention specific matter described in the claims is described in parentheses.
(First embodiment)

  The LED device 20 (semiconductor light emitting device) according to the first embodiment of the present invention will be described with reference to FIGS. First, the outer shape of the LED device 20 will be described with reference to FIG. 1A and 1B are external views of the LED device 20, wherein FIG. 1A is a plan view and FIG. 1B is a front view.

  When the LED device 20 is viewed from above as shown in FIG. 5A, the substantially square circuit board 22, the metal frame 21 (frame body) installed on the circuit board 22, and the inside of the frame part 21 c included in the metal frame 21 The fluorescent screen 23 occupying the area is visible. The circuit board may be rectangular. There are electrodes 24 for electrical connection at the upper left corner and the lower right corner of the circuit board 22 (other wirings and electrodes on the circuit board 22 are not shown, and so on). The metal frame 21 has extending portions 21d on the top, bottom, left, and right of the frame portion 21c, and a portion of the extending portion 21d that protrudes from the circuit board 22 becomes an attachment portion 21a for attaching to another device. The attachment portion 21a has a screw hole 21b.

  When the LED device 20 is viewed from the front as shown in (b), the circuit board 22 and the metal frame 21 covering the circuit board 22 are visible. As can be seen from (a), the metal frame 21 covers a part of the circuit board 22. In (b), the extending portion 21d extending from the frame portion 21c of the metal frame 21 to the front, rear, left and right is bent at the end portion of the circuit board 22 and locks the circuit board 22 (the rear extending portion 21d). Is not shown). Further, the mounting portion 21a of the metal frame 21 and the bottom surface of the circuit board 22 have the same height.

  The internal structure of the LED device 20 will be described with reference to FIGS. FIG. 2 is a cross-sectional view of the LED device 20 drawn along the line AA shown in FIG. A metal frame 21 is installed along the periphery of the circuit board 22. The metal frame 21 includes a frame portion 21c and an extension portion 21d, and the extension portion 21d includes an attachment portion 21a. The attachment portion 21a has a screw hole 21b. In addition, six LED dies 26 (semiconductor light emitting elements) can be seen on the upper surface of the circuit board 22 and inside the metal frame 21, and each LED die 26 has a hemispherical (dome-shaped) light-transmitting surface on the upper surface and side surfaces. It is covered with the sexual member 25. A fluorescent plate 23 exists above the translucent member 25 through an air layer, and an end portion of the fluorescent plate 23 is bonded to a frame portion 21 c of the metal frame 21.

  FIG. 3 is a plan view showing a state in which the fluorescent plate 23 is removed from the LED device 20 shown in FIG. The frame portion 21c of the metal frame 21 is open, and the upper surface of the circuit board 22 and the 26 LED dies 26 mounted on the circuit board 22 can be seen from the opening. Each LED die 26 is at the bottom of a dome-shaped translucent member 25 that appears to be substantially circular from the top.

  The circuit board 22 is a ceramic substrate and is made of alumina having high thermal conductivity and high reflectance. The circuit board 22 may be an aluminum board having an insulating layer and a wiring layer on the surface of the highly reflective aluminum board. The metal frame 21 is manufactured by pressing a metal plate (SUS or the like) of about 100 μm. At the same time, the screw hole 21b is formed. Since the LED device 20 is attached to another device through the screw hole 21b of the metal frame 21, the ceramic circuit board 22 is not broken. Further, instead of the metal frame 21, a frame made of plastic manufactured by injection molding may be substituted. Since the metal frame 21 has high thermal conductivity, it is useful for heat dissipation of the LED device 20.

  The LED die 26 is a light emitting diode, and includes a transparent substrate such as a sapphire substrate. A semiconductor layer is formed on the transparent substrate, and an anode electrode and a cathode electrode are provided on the semiconductor layer. The sapphire substrate has a thickness of about 80 to 120 μm, and the semiconductor layer has a thickness of less than 10 μm. The LED die 26 may be mounted by face-down mounting (also called flip chip mounting) or face-up mounting. Here, the face-down mounting is to directly connect the anode electrode and the cathode electrode to the electrode formed on the upper surface of the circuit board 22, and the face-up mounting is to die-bond the sapphire substrate to the circuit board 22 and to connect the anode electrode. The cathode electrode is connected to an electrode formed on the upper surface of the circuit board 22 by a wire.

  The translucent member 25 is a transparent silicone resin and is molded with a mold. When separating the dome part (refer FIG. 5) of the translucent member 25, it will be easy to manufacture if the dome part is separated by etching after molding. Further, the dome-shaped translucent member 25 may be formed by potting. In this case, in the region of the circuit board 22 in contact with the bottom surface of the translucent member 25, the affinity with the silicone resin is increased, the affinity in the peripheral region is decreased, and the translucent property is utilized by utilizing the surface tension of the silicone resin. The shape of the member 25 is controlled.

  In addition, since it is the structure which coat | covered one LED die 26 for every dome part of the translucent member 25, a dome part may be small. By doing so, the LED device 20 can be thinned. That is, even if a large number of LED dies 26 are mounted on the circuit board 22 to brighten the LED device 20, the dome portion is reduced in size if a dome portion made of the translucent member 25 is formed for each LED die 26. In this embodiment, each dome portion covers the LED die 26 one by one, but several LED dies may be collectively covered in a dome shape.

  The fluorescent plate 23 is a silicone resin obtained by kneading and curing a phosphor and has a thickness of about 100 μm. Since the fluorescent plate 23 is away from the LED die 26, it is not only less susceptible to the heat generated by the LED die 26, but also reduces color unevenness due to glare (glare) and azimuth.

  Next, the emitted light of the LED device 20 will be described. Since the dome-shaped translucent member 25 is curved so as to protrude outward, the light incident on the translucent member 25 from the LED die 26 reaches the interface between the translucent member 25 and air. When it does, it becomes difficult to totally reflect and it radiate | emits from the translucent member 25 efficiently. Thereafter, the light emitted from the translucent member 25 is reflected directly or several times and enters the fluorescent plate 23. Part or all of the light incident on the fluorescent plate 23 is wavelength-converted by the phosphor in the fluorescent plate 23. As a result, the LED device 20 emits light in a color different from that of the LED die 26 such as white. As described above, the LED die 26 is heated due to light emission. However, since the fluorescent plate 23 is separated from the LED die 26, the temperature rise of the phosphor existing therein can be reduced. As a result, it is possible to use a silicate phosphor that has good characteristics at room temperature and remarkably deteriorates at high temperatures.

  As described above, the portions where the translucent member 25 (see FIG. 2) has a dome shape (hereinafter referred to as a dome portion) may be separated from each other, or a part thereof may be connected. Therefore, both cases are shown in FIG. 4, and the respective features will be described. 4 is a cross-sectional view of the translucent member 25 included in the LED device 20. FIG. 4A shows a case where the dome portion 25a is separated, and FIG. 4B shows a case where the dome portion 25b is connected by the connecting portion 25c. Shows the case. In the description of this figure, the translucent member 25 is distinguished from the dome portions 25a and 25b and the connection portion 25c based on the partial shape.

  In the LED device 20, since the dome portions 25a and 25b are adjacent to each other at a small distance, when the connection portion 25c is provided at the bottom of the dome portion 25b as shown in FIG. However, it has been confirmed that if the connection portion 25c exists, the connection portion 25c becomes a light guide, and light that has entered the connection portion 25c is difficult to be emitted. On the other hand, when the dome portions 25a are separated as shown in (a), the stray light is eliminated and the light emission efficiency is improved. The structure (a) or (b) is selected depending on whether the light emission efficiency is important or the ease of production is important. When a mold is used to form the dome portion 25a, a translucent member is once molded so as to have the connection portion 25c as shown in (b), and the dome portion 25a is separated as shown in (a) by etching. do it.

In the LED device 20, the fluorescent plate 23 is bonded to the metal frame 21, but the method of supporting the fluorescent plate by the frame is not limited to bonding. For example, when the fluorescent plate is hard and the frame is made of plastic, a locking claw may be prepared on the frame and the fluorescent plate may be locked. Moreover, although the attachment part 21a of the LED apparatus 20 respond | corresponded to screwing, the attachment method to another apparatus is not limited to screwing, For example, the shape where an attachment part is inserted in a socket may be sufficient.
(Second Embodiment)

  Although the metal frame 21 of the LED device 20 has four attachment portions 21a, the number of attachment portions is not limited to four. As a second embodiment in which the number of attachment portions is reduced and the attachment process to other devices is reduced, an LED device 50 having two attachment portions 51a will be described with reference to FIG.

FIG. 5 is a plan view of the LED device 50. When the LED device 50 is viewed from above, a square circuit board 52, a metal frame 51 (frame body) installed on the circuit board 52, a fluorescent plate 53 occupying an area inside the frame portion 51 c included in the metal frame 51, Can be seen. There are electrodes 54 for electrical connection in the upper right corner and lower left corner of the circuit board 52 (other wirings and electrodes on the circuit board 52 are not shown). The metal frame 51 has two extending portions 51d in an oblique direction toward the lower right, and each extending portion 51d is connected to the frame portion 51c. A portion of the extended portion 51d that protrudes from the circuit board 52 becomes an attachment portion 51a for attachment to another device. The attachment portion 51a has a screw hole 51b. The structure in the frame 51c is the same as that shown in FIGS.
It is equal to the internal structure of the D device 20.

As described above, since the LED device 50 has two attachment portions, the number of attachment steps can be reduced. Moreover, although the LED device 50 is provided with the extending portions 51d in the oblique direction, two extending portions may be provided in the horizontal direction or the vertical direction in the drawing. Since the circuit board 52 of the LED device 50 is less covered with the metal frame 51 than the circuit board 22 of the LED device 20 of FIG. 1, when components other than the LED die must be added on the circuit board 52, It becomes easy to mount this part.
(Third embodiment)

  In the first and second embodiments, the LED die 26 on the circuit boards 22 and 52 may be face-up mounting or face-down mounting (hereinafter referred to as flip chip mounting). Flip chip mounting does not require a wire for electrical connection, so the mounting area can be small, and the shadow of the wire is eliminated, resulting in high luminous efficiency. Moreover, since the semiconductor layer for light emission and the circuit board are close to each other, the heat dissipation efficiency is high. Therefore, in addition to the effects of the present invention, the LED device 60 will be described with reference to FIG.

  FIG. 6 is a cross-sectional view of the periphery of the LED die 66 included in the LED device 60. The LED die 66 is flip-chip mounted on the circuit board 62 via the protruding electrode 66d. The electrodes of the circuit board 62 are not shown. The LED die 66 has a semiconductor layer 66c formed under the sapphire substrate 66a, and a protruding electrode 66d is attached to the lower surface of the semiconductor layer 66c. Further, the side surfaces of the sapphire substrate 66a and the semiconductor layer 66c are covered with a reflecting member 66b. The upper surface of each LED die 66 is covered with a translucent member 65, and the fluorescent plate 63 covers the upper part thereof. The frame not shown is equivalent to that shown in FIGS. 1 and 5 and supports the fluorescent plate 63.

  The circuit board 62, the fluorescent plate 63, and the translucent member 65 are made of the same material as the circuit boards 22, 52, the fluorescent plates 23, 53, and the translucent member 25 of the LED devices 10 and 50. The reflective member 66b is obtained by kneading and curing reflective fine particles such as titanium oxide and alumina in a silicone resin, and has a thickness of about 100 μm. The protruding electrode 66d is a bump having Cu or Au as a core, and has a height of about 10 to 30 μm.

  The light emitted from the semiconductor layer 66c of the LED die 66 is emitted only upward of the LED die 66 by the reflective layer and the reflective member 66b included in the semiconductor layer 66c. At this time, the refractive index of the sapphire substrate 66a is about 1.7, whereas the refractive index of the translucent member 65 is often around 1.4 to 1.5. The efficiency of extracting light is higher when light is emitted into the air via the translucent member 65 than when light is emitted. Note that the translucent member 65 can be omitted when this improvement in efficiency is ignored. The translucent member 65 may be flip-chip mounted on the circuit board 62 in a state of being applied to the LED die 66 in advance, or may be applied after the LED die 66 is flip-chip mounted on the circuit board 62. At this time, the translucent member 65 may slightly adhere to the surface of the circuit board 62.

  As described above, the light emission efficiency, which is one of the features of flip chip mounting, can be improved. Further, since the translucent member exists only on the upper surface of the side surface of the LED die 66, the LED die 66 can be densely arranged on the circuit board 62. At this time, since the semiconductor layer 66c and the circuit board 62 are close to each other through the protruding electrode 66d, the heat dissipation efficiency is also high. The LED die 66 includes the reflecting member 66b on the side surface. However, if the sapphire substrate 66a is thinned, the light to be emitted from the side surface direction is reduced, so that the reflecting member 66b can be omitted.

20, 50, 60 ... LED device (semiconductor light emitting device),
21, 51 ... Metal frame (frame),
21a, 51a ... mounting part,
21b, 51b ... screw holes,
21c, 51c ... frame part,
21d, 51d ... extension part,
22, 52, 62 ... circuit board,
23, 53, 63 ... fluorescent plate,
24, 54 ... electrodes,
25, 65 ... translucent member,
25a, 25b ... Dome,
25c ... connection part,
26, 66 ... LED die (semiconductor light emitting element),
66a ... sapphire substrate,
66b ... reflective member,
66c ... semiconductor layer,
66d: Projection electrode.

Claims (10)

In a semiconductor light-emitting device comprising a circuit board, a plurality of semiconductor light-emitting elements mounted on the circuit board, and a phosphor that converts the wavelength of light emitted from the semiconductor light-emitting elements,
A frame that covers a part of the upper surface of the circuit board, has a mounting region for the semiconductor light emitting element, and has an attachment portion for attachment to another device;
A semiconductor light emitting device, comprising: a fluorescent plate fixed to the frame, including the phosphor, and covering an upper portion of the semiconductor light emitting element.   The semiconductor light emitting device according to claim 1, wherein the frame is made of metal.   The semiconductor light emitting device according to claim 1, wherein the fluorescent plate is bonded to the frame.   4. The semiconductor light emitting device according to claim 1, wherein the attachment portion of the frame body is provided at two places. 5.   The semiconductor light-emitting device according to claim 1, wherein the semiconductor light-emitting element is covered with the transparent light-transmitting member.   6. The semiconductor light emitting device according to claim 5, wherein the translucent member covers the semiconductor light emitting element in a dome shape.   The semiconductor light-emitting device according to claim 1, wherein the semiconductor light-emitting element is flip-chip mounted on the circuit board.   The semiconductor light-emitting device according to claim 5, wherein each of the semiconductor light-emitting elements is individually covered with the translucent member.   The semiconductor light-emitting device according to claim 5, wherein the translucent member is coated on an upper surface of the semiconductor light-emitting element.   The semiconductor light-emitting device according to claim 7, wherein the semiconductor light-emitting element includes a reflecting member on a side surface.

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