JP2017135301A - LED module and lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED module which inhibits short circuits between electrodes of an LED chip mounted in a flip-chip manner with a simple structure, and to provide a lighting device in which the LED module is disposed.SOLUTION: An LED module 1 includes: a substrate 2 having a recessed part 8 on one surface 2a side; a conductor 3 provided on a bottom surface of the recessed part 8; and a flip-chip type LED 4 having electrode parts 11, 11 electrically connected with the conductor 3 in the recessed part 8.SELECTED DRAWING: Figure 2

Description

  Embodiments described herein relate generally to an LED module using a flip-chip type LED and an illumination device provided with the LED module.

  In recent years, an LED module mounted on a lighting device has been required to improve the mounting density of LED elements on a substrate due to downsizing and higher output of the lighting device. For this reason, the LED module uses flip chip mounting in which the LED chip is directly mounted on the substrate. That is, the LED module is formed by flip-chip mounting a large number of LED chips on one surface side of a substrate, and sealing these LED chips with a translucent resin mixed with a phosphor. In the LED chip, bumps (metal protrusions) attached to the electrodes are connected to pads (wiring patterns) provided on the substrate by a conductive adhesive or solder.

  However, an adhesive or solder may flow between the bumps and pads of the LED chip between the bumps. Thereby, the insulation distance between the bumps along the substrate surface of the LED chip is not secured, and a short circuit between the bumps and a short circuit between the pads (wiring patterns) occur, resulting in a decrease in the manufacturing yield of the LED module. For this reason, what interposes insulating materials, such as insulating resin, between the bumps of LED chip or between LED chip and a substrate is proposed (for example, refer to patent documents 1 or 2). In addition, there has been proposed a technique in which a groove is provided on a substrate between bumps of an LED chip and an adhesive material flowing into the groove is received to prevent diffusion (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 10-92976 (page 4, FIG. 5) JP 2009-99597 A (page 5, FIG. 2) Japanese Patent Laid-Open No. 2003-46142 (page 3, FIG. 1)

  In the case where an insulating material such as an insulating resin is interposed between the bumps of the LED chip, there is a drawback that it takes time for flip chip mounting, and the LED module is expensive due to the provision of the insulating material. Moreover, the thing which accept | permits the adhesive material which flowed out by providing a groove | channel on the board | substrate between bumps, and has prevented the spreading | diffusion has the fault that it is difficult to make an LED module thin, because a board | substrate becomes a suitable thickness.

  An object of an embodiment of the present invention is to provide an LED module capable of suppressing a short circuit between electrodes of a flip-chip mounted LED chip with a simple configuration, and an illumination device provided with the LED module.

  The LED module of this embodiment is formed to include a substrate, a conductor, and an LED. The substrate has a recess formed on one side. The conductor is provided on the bottom surface of the recess. The LED is of a flip chip type, and its electrode portion is electrically connected to a conductor in the recess of the substrate.

  According to the LED module of the present embodiment, since the electrode portion of the LED is electrically connected to the conductor in the recess of the substrate, the solder or conductive adhesive that electrically connects the electrode portion of the LED and the conductor is recessed. From this, it can be expected that the insulation distance along the one surface of the substrate between the electrode portions is secured, and a short circuit between the electrode portions of the LED can be suppressed.

It is a schematic top view of the LED module which shows the 1st Embodiment of this invention. Similarly, an LED module is shown, (a) is a partial schematic cross-sectional view, and (b) is a partial schematic vertical cross-sectional view. Similarly, the LED module when an electrode part and a conductor are electrically connected is shown, (a) is a partial schematic cross-sectional view, and (b) is a partial schematic vertical cross-sectional view. It is a schematic longitudinal cross-sectional view of the illuminating device which shows the 2nd Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, a first embodiment of the present invention will be described.

  The LED module 1 according to the present embodiment is used as a light source in an illumination device such as an LED lamp, and is also called a light emitting module or a light emitter. As shown in FIGS. 1 to 3, a COB (Chip On Board) is used. It is composed of mold modules. In FIG. 1, the LED module 1 is formed by including a substrate 2, a conductor 3, an LED chip 4 as an LED, and a translucent resin 5. In the LED module 1, the LED chip 4 is electrically connected and fixed to the conductor 3 with solder 6 (shown in FIG. 2).

In this embodiment, the substrate 2 is made of alumina ceramics having a thickness of 0.64 mm formed in a substantially square shape, and a pair of wiring patterns 7 and 7 are provided in a substantially U-shape on the one surface 2a side. A plurality of recesses 8 are provided in series between the wiring patterns 7 and 7 in a plurality of rows. The recess 8 is formed in a rectangle whose width is slightly larger than the width in the short direction of the LED chip 4, and is formed so that the LED chip 4 straddles between the recesses 8, 8. In addition, the recesses 8 at both ends of each row are formed so as to reach the wiring patterns 7, respectively, and are formed so as to have a predetermined interval between each row. Moreover, the recessed part 8 is formed so that the depth from the one surface 2a of the board | substrate 2 may be 100-200 micrometers.

The recess 8 is formed using, for example, a mold material in a manufacturing process for forming the substrate 2 by alumina ceramics. As a result, a plurality of recesses 8 having a predetermined shape and depth are easily formed on the one surface 2a of the substrate 2 in the above-described series and multiple rows of patterns. The concave portion 8 may be formed by cutting the one surface 2a of the substrate 2 into a predetermined shape and depth.

The pair of wiring patterns 7 and 7 are formed with a predetermined width over the entire length, and copper (Cu) and nickel (Ni), palladium (Pd), gold laminated on the surface of the copper in order by plating. (Au). The thickness of copper is, for example, 50 μm, and the thickness of the laminate of nickel, palladium, and gold is, for example, 2 μm. The pair of wiring patterns 7 and 7 are electrically connected to a connector 9 provided at one end of the substrate 2.

The conductor 3 is provided over almost the entire bottom surface of the recess 8. The conductors 3 and 3 at both ends of each column are formed to extend to the wall portions of the recesses 8 and 8, respectively, and are electrically connected to the pair of wiring patterns 7 and 7. The conductor 3 is made of the same metal material as the wiring pattern 7 and is formed to have a thickness of the wiring pattern 7. That is, the conductor 3 is provided in the recess 8 so as not to protrude from the one surface 2 a of the substrate 2. The pair of wiring patterns 7 and 7 and each conductor 3 are simultaneously formed by printing, etching, plating growth, or the like.

As shown in FIG. 2, the LED chip 4 is a flip chip type LED in which positive and negative electrode portions 11 are provided on the lower surface side of a main body portion 10 made of, for example, sapphire and formed in a rectangular parallelepiped shape. In the present embodiment, the electrode portions 11 and 11 are configured by electrodes 12 a and 12 b and bumps 13 and 13. One of the electrodes 12 a and 12 b is a positive electrode and the other is a negative electrode, and is electrically connected to a light emitting layer (not shown) provided on the lower surface side of the main body 10. The light emitting layer emits, for example, blue light when energized. That is, the LED chip 4 emits blue light, for example. Blue light is radiated from the translucent main body 10 in all directions.

The bumps 13 and 13 are made of a conductive metal material such as copper (Cu), are formed in a protruding shape, and are attached to the electrodes 12a and 12b so as to be electrically connected to the electrodes 12a and 12b. The bumps 13 and 13 electrically connect the electrodes 12a and 12b and the conductors 3 and 3, and the size and shape of the bumps 13 and 13 are such that an insulation distance between the bumps 13 and 13 can be secured and can be inserted into the recess 8. Is set, and in this embodiment, it is formed in a convex bottomed rectangular tube shape or a rectangular column shape. The electrode portions 11 and 11 may be formed as electrodes of the LED chip 4 by integrally forming the electrodes 12 a and 12 b and the bumps 13 and 13.

The LED chip 4 is electrically connected to the conductors 3 and 3 by inserting the bumps 13 and 13 into the recesses 8 and 8 so that the main body 10 straddles the recesses 8 and 8 in each row. Here, the bump 13 is electrically connected to the conductor 3 by, for example, solder 6. The solder 6 does not flow out to the one surface 2a of the substrate 2 between the bumps 13 and 13 as shown in FIG. 2A when the bumps 13 and the conductor 3 are electrically connected, as shown in FIG. As shown, the predetermined amount is provided so as not to flow out to the one surface 2a of the substrate 2 on both sides of the main body portion 10 in the short direction.

The solder 6 melts and solidifies, thereby fixing the bumps 13 to the conductor 3 and electrically connecting the electrode portion 11 and the conductor 3. As shown in FIG. 3A, a predetermined amount of the solder 6 is placed on the conductors 3, 3 on both sides between the recesses 8, 8. Further, the bulk solder 6 before melting is placed at the center in the width direction of the conductor 3 as shown in FIG. Then, as shown in FIG. 3A, after the bumps 13 and 13 of the LED chip 4 are placed on the solders 6 and 6, for example, the substrate 2 is put in a heating furnace and the solder 6 is melted at a predetermined temperature. The substrate 2 is taken out of the heating furnace and the solder 6 is solidified.

The molten solder 6 spreads on the conductor 3, stays in the recess 8, and overflows to the one surface 2a side of the substrate 2 and does not flow out as shown in FIG. The bumps 13 and 13 are electrically connected to the conductors 3 and 3 by the solidified solder 6. The LED chip 4 is fixed between the conductors 3 and 3. In this way, the plurality of LED chips 4 are flip-chip mounted on the surface 2 a side of the substrate 2, and are electrically connected to the pair of wiring patterns 7 and 7 via the conductor 3.

As shown in FIG. 1, the pair of wiring patterns 7, 7 excluding the conductor 3, the LED chip 4, and the connector 9 side is surrounded by a frame portion 14 having a predetermined width and height. The frame portion 14 is also called a bank, a bank, or the like, and is made of, for example, a silicone resin. The translucent resin 5 is filled in the frame portion 14. The translucent resin 5 is filled up to the top portion 14a of the frame portion 14, and seals the conductor 3, the LED chip 4, and the wiring pattern 7.7. The surface 5a of the translucent resin 5 is flat as shown in FIG.

The translucent resin 5 is made of, for example, an electrically insulating silicone resin and contains a phosphor (not shown) at a predetermined concentration. For example, when the LED module 1 emits white light, a YAG phosphor that converts a part of blue light of the LED chip 4 into yellow light is contained. When the LED module 1 emits blue light, it does not contain a phosphor. The translucent resin 5 contains a light diffusing material as necessary.

In FIG. 1, a connector 16 connected to an output line 15 of a lighting device (not shown) is attached to the connector 9.

Next, the operation of the first embodiment of the present invention will be described.

  When power is supplied from the lighting device to the connector 9 of the LED module 1, a predetermined current is supplied to each of the plurality of LED chips 4 in each column connected to the pair of wiring patterns 7 and 7 via the conductor 3. Flows. The LED chip 4 generates heat and emits blue light. A part of the blue light is wavelength-converted into yellow light by the YAG phosphor contained in the translucent resin 5. Then, white light in which blue light and yellow light are mixed (mixed color) is emitted from the surface 5 a of the translucent resin 5. White light is emitted to the front side of the LED module 1.

  The heat generated by the LED chip 4 is directly conducted to the translucent resin 5 and also conducted to the substrate 2 through the conductor 3. And it is mainly emitted from the surface 5 a of the translucent resin 5 to the external space and from the other surface opposite to the one surface 2 a of the substrate 2.

  In the LED module 1, the bumps 13 and 13 of the LED chip 4 are electrically connected to the conductors 3 and 3 by the solder 6 in the recesses 8 and 8, and the solder 6 does not flow out from the recess 8 to the one surface 2 a of the substrate 2. is there. Thereby, the insulation distance between the bumps 13 and 13 is prevented from being narrowed by the solder 6, and the insulation distance between the electrode portions 11 and 11 along the one surface 2 a of the substrate 2 is ensured. In the LED chip 4, a short circuit between the electrodes 12 a and 12 b when energized is suppressed. The LED module 1 improves the manufacturing yield.

  In the LED module 1 of the present embodiment, the substrate 2 is formed of alumina ceramics. One surface 2a of the substrate 2 is a white surface and is a highly reflective surface. Since the solder 6 does not flow out to the one surface 2a of the substrate 2, each of the blue light emitted from the LED chip 4 and the yellow light generated by the wavelength conversion of the YAG phosphor is well reflected by the one surface 2a of the substrate 2. Is done. Thereby, the fall of the light extraction efficiency of LED module 1 is suppressed.

  Moreover, the alumina ceramic can form the recessed part 8 in the one surface 2a side of the board | substrate 2 with the type | mold material at the time of manufacture of the board | substrate 2. FIG. Thereby, the increase in the manufacturing cost of the board | substrate 2 by formation of the recessed part 8 is suppressed, and the LED module 1 can be manufactured cheaply.

  If the solder 6 flows out from the recess 8 to the one surface 2a of the substrate 2, the electrode portions 11 and 11 (bumps 13 and 13) are narrowed by the solder 6 electrically connected to the bumps 13, and a short circuit occurs when energized. It becomes easy. Here, a translucent resin 5 having electrical insulation is interposed between the bumps 13 and 13. However, since the translucent resin 5 is not necessarily in close contact with the one surface 2a of the substrate 2, the insulation distance between the bumps 13 and 13 along the one surface 2a of the substrate 2 is difficult to be secured by the solder 6 that has flowed out. Sometimes short circuits are likely to occur. The short circuit of the LED chip 4 becomes a defective product of the LED module 1 and decreases the manufacturing yield.

  Of the light in the translucent resin 5, the light incident on the solder 6 is irregularly reflected as the reflectance decreases. As a result, depending on the shape and amount of leakage of the solder 6, the white light emitted from the surface 5a of the translucent resin 5 is likely to be unevenly emitted, and the light extraction efficiency may be reduced.

  In the LED module 1 of this embodiment, the conductor 3 is provided on the bottom surface of the recess 8 of the substrate 2, and the electrode portions 11 and 11 (bumps 13 and 13) of the LED chip 4 are electrically connected to the conductor 3 in the recess 8. Since the solder 6 to be electrically connected is unlikely to flow out from the recess 8 to the one surface 2a side of the substrate 2, an insulation distance along the one surface 2a of the substrate 2 between the electrode portions 11 and 11 (bumps 13 and 13) is secured. Further, it is possible to suppress a short circuit between the electrodes 12a and 12b of the LED chip 4, thereby having an effect of improving the manufacturing yield.

Further, since the substrate 2 is made of ceramics, the concave portion 8 can be easily formed on the one surface 2a of the substrate 2 using a mold material at the time of manufacturing the substrate 2, thereby making the substrate 2 having the concave portion 8 inexpensive. It has the effect that it can be manufactured.

The substrate 2 may be formed of a synthetic resin plate or a metal plate having high thermal conductivity. In the case of a metal plate, an insulating layer is formed on the surface 2 a side of the substrate 2 including the recess 8. Then, in order to improve the light extraction efficiency, a metal reflection layer is formed on the insulating layer excluding the recess 8. Similarly, in the case of a synthetic resin plate, a metal reflection layer may be formed. The recess 8 may be formed on the insulating layer by forming a thick insulating layer on the planar base material to be the substrate 2.

Next, a second embodiment of the present invention will be described.

The illuminating device 21 of this embodiment is comprised by the lamp device, as shown in FIG. The illuminating device 21 includes the LED module 1, the lighting device 22, and the device main body 23 shown in FIG. The LED module 1 and the lighting device 22 are disposed in the device main body 23.

The lighting device 22 includes a flat circuit board 24 and lighting circuit components 25 to 27 mounted on both surfaces of the circuit board 24, and the lighting circuit that supplies power to the LED chip 4 of the LED module 1. Is forming. The circuit board 24 is made of, for example, a glass epoxy material, is formed in a substantially circular shape, and a circular central hole 28 serving as an opening is provided in the central portion thereof.

The circuit board 24 has the LED module 1 mounted on the one surface 24a side via a plurality of spacers 29. The light emitting part of the LED module 1 faces the central hole 28, and the connector 9 is connected to the connector 16 of the output line 15 led out from the circuit board 24. The input terminal 30 of the lighting device 22 is provided at an end portion on the one surface 24 a side of the circuit board 24.

The apparatus body 23 is made of a synthetic resin, such as polybutylene terephthalate (PBT) resin, with an opening 31 on one end side 23a, a flat plate portion 32 on the other end side 23b, and a circular insertion portion formed at the center of the flat plate portion 32. 33 is formed in a substantially cylindrical shape. On the upper surface 32a of the flat plate portion 32, a cylindrical protrusion 33 protruding outward at the center thereof, and a pair of lamp pins 34, 34 adjacent to the protrusion 33 (only one is shown in FIG. 4). .) Is arranged. A heat radiating member 35 is provided on the protrusion 33. The pair of lamp pins 34, 34 are connected to the input terminal 30 of the lighting device 22 by an input line 36.

The heat radiating member 35 is molded by, for example, aluminum die casting, and is attached to the upper surface of the protruding portion 33 so as to face the insertion portion 33. The heat radiating member 35 has a heat conducting member 37 attached thereto. The heat conducting member 37 is formed in a cylindrical shape from a heat conductive metal such as aluminum (Al), and the end surface of the one end side 37a is brought into close contact with the other surface 2b of the substrate 2 of the LED module 1 to thereby form a substrate. 6 is attached with an adhesive or the like.

A protective cover 38 is attached to the opening 31 of the apparatus main body 23. The protective cover 38 is molded from, for example, a polycarbonate (PC) resin having translucency, and the outer surface 38a is flat and formed in a circular shape. The protective cover 38 is configured so that the inside of the apparatus main body 23 is substantially closed by the locking claws 40 of the protrusions 39 provided intermittently on the inner surface 38 b being locked in the locking grooves 41 of the opening 31. It is attached. Further, on the peripheral side of the outer surface 38a of the protective cover 38, rectangular parallelepiped finger-hanging portions 42, 42 are formed to project.

Further, the apparatus main body 23 houses a reflecting mirror 43. The reflecting mirror 43 is formed in a substantially elliptical shape, and is provided so as to be sandwiched between the circuit board 24 and the protective cover 38 so that the top side opening 44 faces the central hole 28 of the circuit board 24. The reflecting mirror 43 is formed of, for example, aluminum, and an inner surface 43a is formed on the reflecting surface.

The lighting device 21 as a lamp device is attached to a lighting fixture. When an external power source is turned on to the lighting fixture, this AC power source is supplied to the lighting device 22 via the pair of lamp pins 34 and 34. When the lighting device 22 operates and a predetermined current is supplied to the LED chip 4 of the LED module 1, for example, white light is emitted from the LED module 1. The white light passes through the central hole 28 of the circuit board 24 and the top side opening 44 of the reflecting mirror 43, passes through the protective cover 38, and illuminates the external space of the lighting fixture. Since the illuminating device 21 includes the LED module 1 in which a short circuit between the electrode portions 11 and 11 of the LED chip 4 is suppressed, the illuminating device 21 can emit stable illumination light over a long period of time. Thereby, the lighting fixture can reduce maintenance, such as replacement | exchange work of the illuminating device 21. FIG.

According to the illuminating device 21 of the present embodiment, a short circuit between the electrode portions 11 and 11 of the LED chip 4 in the LED module 1 is suppressed, so that a predetermined lifetime is ensured and the quality is improved. Have

In addition, in this embodiment, although the illuminating device 21 was comprised in the lamp device, it is not restricted to this, While arrange | positioning the LED module 1 of this embodiment in the apparatus main body as an instrument main body or a housing | casing, The lighting fixture may be a lighting device including a lighting device that supplies power to the LED chip 4.

Further, the above-described embodiment of the present invention is presented as an example, and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... LED module, 2 ... Board | substrate, 3 ... Conductor, 4 ... LED chip as LED, 8 ... Recessed part, 11 ... Electrode part, 21 ... Illuminating device, 22 ... Lighting apparatus, 23 ... Device main body

Claims (3)

A substrate having a recess on one side;
A conductor provided on the bottom surface of the recess;
A flip chip type LED having an electrode portion electrically connected to the conductor in the recess;
An LED module comprising:   The LED module according to claim 1, wherein the substrate is made of ceramics. An LED module according to claim 1 or 2;
An apparatus main body in which the LED module is disposed;
A lighting device for supplying power to the LED;
An illumination device comprising:

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