JP2012015329A - Circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit board capable of suppressing sulfurization reaction and silver migration on a soldering pad portion and improving reliability of soldering of a surface mounted component.SOLUTION: A circuit board comprises: a module substrate; wiring patterns 25 and 26 mainly made of silver; an electrically insulated protection layer 37; a capacitor 65 having a pair of electrodes 67; and solder. The protection layer 37 is provided on soldering pad portions 25d and 26f and an intermediate pad 27 that are connected to the wiring patterns. The protection layer 37 has slot-shaped openings 37a and 37b, and four corners of these openings are formed in a circular arc shape or in an oblique shape. A capacitor 65 is disposed in the openings across the soldering pad portions. Solder is blocked by the edges of the openings 37a and 37b and covers the whole surface of the soldering pad portions. The electrodes are soldered to pad portions 25d, 26f, and 27 with the solder.

Description

  Embodiments described herein relate generally to a circuit board in which surface-mounted components are soldered to a circuit board.

  2. Description of the Related Art An LED mounting substrate in which a surface mounting type LED chip is disposed on a solder pad provided in a pair with a mounting substrate and the chip is soldered to the solder pad is known as a conventional technique.

  When a light emitting device equipped with this LED mounting board is used for illumination or the like by white light emission, the wiring pattern on the mounting board connected to the LED is made of Ag (silver). Since the color of the emitted light is a similar color, the light color reflected by the wiring pattern or the like is preferable because it hardly affects the white light.

  By the way, the surface mount type electric parts are soldered through a reflow furnace. In this case, the wettability of the solder with respect to the silver wiring pattern is inferior to a general wiring pattern in which copper, nickel, and gold are laminated on the mounting substrate in the order described. Therefore, there is a possibility that the surface mount component is soldered in a state where the solder does not spread over the entire surface of the solder pad formed integrally with the silver wiring pattern.

  In such incomplete soldering conditions, there may be a disadvantage that the reliability of soldering of surface mount components will decrease, and when the amount of solder is increased to improve this, as the amount of solder becomes excessive The excess solder may be formed as balls around the solder pads. At the same time, due to the incomplete soldering, the exposed part of the silver solder pad deteriorates due to sulfur reaction with the sulfur component in the atmosphere, so that the resistance increases due to the progress and the electrical adverse effect is adversely affected. Can be considered. In addition, there may be a disadvantage that a silver microphone is generated from the exposed portion as a base point, resulting in a short circuit. These disadvantages are desired to be improved in order to improve the quality of the product.

JP 2009-158660 A

  The embodiment is intended to provide a circuit board capable of suppressing the sulfurization reaction and silver milation in the solder pad portion and improving the reliability of soldering of the surface mount component.

  In order to solve the above problems, a circuit board includes a circuit board, a wiring pattern mainly composed of silver, an electrically insulating protective layer, a surface-mounted component, and solder. A wiring pattern is provided on the circuit board. The wiring pattern has a solder pad portion. A protective layer is applied to the wiring pattern. The protective layer has an opening in the shape of a long hole, and the four corners of the opening are formed in an arc or obliquely. Solder pad portions adjacent to each other in pairs are disposed at both ends in the longitudinal direction of the opening. The surface mount component has a pair of electrodes, and the surface mount component is disposed in the opening over the solder pad portion. It is characterized in that the solder is dammed at the edge of the opening to cover the entire surface of the solder pad portion, and the electrode is soldered to the solder pad portion with this solder.

  According to the circuit board of the embodiment, it is possible to expect an effect that it is possible to suppress the sulfurization reaction and silver milation in the solder pad portion and to improve the reliability of soldering of the surface mount component.

It is a perspective view which shows the lamp periphery of the road light provided with the circuit board which concerns on Example 1. FIG. It is a perspective view which shows the light source device with which the lamp of FIG. 1 is provided. It is a schematic front view which shows the light source device of FIG. It is a front view which shows the light emitting module with which the light source device of FIG. 2 is provided. It is a front view which shows the light emitting module of FIG. 4 in the state which passed through the 1st manufacturing process. It is a front view which shows the light emitting module of FIG. 4 in the state which passed through the 2nd manufacturing process. It is an enlarged view of F7 part in FIG. It is an enlarged view of F8 part in FIG. It is sectional drawing which follows F9-F9 line in FIG. It is sectional drawing shown along F10-F10 line | wire in FIG.

  The circuit board according to the first embodiment includes a circuit board; a wiring pattern mainly composed of silver provided on the circuit board having a solder pad portion; and a long hole-shaped opening. In addition, the four corners of the opening are formed as arcs or diagonally, and the solder pad portions are disposed at both ends in the longitudinal direction of the opening, respectively, and a pair of electrodes is provided. A surface-mounted component disposed over the solder pad portion in the opening; and provided to cover the entire surface of the solder pad portion by being dammed by an edge of the opening and soldering the electrode to the solder pad portion And an attached solder.

  The circuit board according to the first embodiment is not limited to the light emitting module described in the first embodiment, and any circuit can be used as long as the circuit board has a configuration in which a surface mounting component is soldered to a circuit board. It can also be applied to plates.

  In the first embodiment, the circuit board may be made of a synthetic resin such as an epoxy resin, a metal base board in which an insulating layer is laminated on a metal plate, or an inorganic material such as ceramics. When the module substrate is made of white ceramic, the ceramic is selected from aluminum oxide (alumina), aluminum nitride, boron nitride, silicon nitride, magnesium oxide, forsterite, steatite, and low-temperature sintered ceramics. Alternatively, these composite materials can be used, and in particular, white alumina that is inexpensive, has high light reflectance, and is easy to process can be suitably used. In the first embodiment, the wiring pattern mainly composed of silver includes a pure silver wiring pattern and a wiring pattern formed by silver plating or the like.

In the first embodiment, the protective layer can be preferably made of an electrically insulating material, for example, an inorganic material, specifically, glass mainly composed of SiO ₂ . Furthermore, the protective layer may or may not be mixed with a pigment that imparts color to this layer. At the same time, the opening of the protective layer having the long hole shape includes an elliptical shape, an elliptical shape, or a shape similar to these.

  In the first embodiment, the shape of each solder pad portion is defined by the longitudinal end portion of the opening of the protective layer attached to the wiring pattern, and the four corner portions of the opening are circular arcs or oblique. When soldering is performed using a reflow furnace, the melted solder is dammed up at the edge of the opening and is surely spread over the corner of the opening to cover the entire surface of the solder pad part. . Since the solder can cover the entire surface of the solder pad portion in this way, it is possible to improve the reliability of soldering of the surface mount component, and at the same time, the sulfurization reaction in the solder pad portion mainly composed of silver In addition, it is possible to suppress silver microphoneation.

  The circuit board of Embodiment 2 is the same as that of Embodiment 1 except that the first separation distance between the electrode and the corner of the opening adjacent to the electrode is from the electrode to the edge of the opening adjacent to the electrode. Shorter than the second separation distance along the center line of the surface-mounted component passing through.

  In the second embodiment, since the distance between the electrode of the surface mounting component soldered to the solder pad portion and the corner of the opening is further shortened in the first embodiment, the solder can be used in the solder pad portion. The electrode can be soldered to the solder pad portion by this solder.

  Hereinafter, the lighting fixture provided with the circuit board of Example 1, for example, a road lamp, is demonstrated in detail with reference to FIGS. Note that FIG. 10 is drawn with the protective layer described later omitted for convenience of explanation.

  Reference numeral 1 in FIG. 1 indicates a road lamp installed for road illumination. The road lamp 1 is formed by attaching a lamp 3 to the upper end of a column 2.

  The column 2 is erected on the side of the road, and its upper part is bent so as to cover the road. The lamp 3 includes a fixture body connected to the column 2, for example, a lamp body 4, a translucent plate 5 attached to the lamp body 4 by closing a lower surface opening of the lamp body 4 facing the road, and the translucent plate 5 It is formed to include at least one light source device 6 that is accommodated in the lamp body 4 so as to face each other. The lamp body 4 is formed by combining a metal, for example, a plurality of aluminum die cast products. The translucent plate 5 is made of tempered glass.

  As shown in FIGS. 2 and 3, the light source device 6 has a plurality of heat radiation fins 14 protruding from the back surface of the device base 11, and a reflector 15 and a light emitting module 21 as a light source are attached to the front surface of the device base 11. This is a unitized configuration.

  The device base 11 is made of a metal, for example, aluminum die-cast, and is formed in a square shape. The apparatus base 11 has a module installation portion 12 (see FIGS. 3 and 10) formed of a square recess opened on the front surface thereof. The bottom surface 12a of the module installation part 12 is flat, and the four side surfaces 12b defining the module installation part 12 are continuous at right angles to each other. The heat radiating fins 14 are formed integrally with the apparatus base 11.

  The reflector 15 is formed by combining the first reflecting plate 15a to the fourth reflecting plate 15d in a trumpet shape. The first reflecting plate 15a and the second reflecting plate 15b are flat mirrors having a flat configuration, and are provided in parallel to each other. The third reflecting plate 15c and the fourth reflecting plate 15d connected to the first reflecting plate 15a and the second reflecting plate 15b are curved mirrors having a curved configuration so that the distance between them gradually increases. Is provided.

  The light source device 6 is fixed in the lamp body 4 with the exit opening of the reflector 15 facing the translucent plate 5. In this fixed state, a part of the device base 11, for example, a peripheral portion is connected to the inner surface of the lamp body 4 so as to be able to conduct heat. This thermal connection can be realized by bringing the peripheral portion into direct contact with the inner surface of the lamp body 4, and the peripheral portion is connected to the inner surface of the lamp body 4 through a heat conductive member such as a metal or a heat pipe having high heat dissipation. It can be realized by connecting to. As a result, the heat generated by the light source device 6 can be released to the outside using the metal lamp body 4 as a heat radiating surface.

  Next, the light emitting module 21 will be described. As shown in FIG. 4 and the like, the light emitting module 21 includes a module substrate 22 forming a circuit board, a wiring pattern 25 for a positive electrode, a wiring pattern 26 for a negative electrode, an alignment mark 35, a first protective layer 37, A second protective layer 38, a plurality of identity marks, for example, a first identity mark 41 to a fourth identity mark 44, a plurality of semiconductor light emitting elements 45, bonding wires 47 to 52, a frame 55, A sealing member such as a sealing resin 57 and a surface mount component such as a connector 61 and a capacitor 65 are provided. The circuit board of Example 1 includes the circuit board, the wiring patterns 25 and 26, the first protective layer 37, the surface-mounted component, and solder described later.

  The module substrate 22 is made of white ceramic, for example, white aluminum oxide. The module substrate 22 may be formed of only aluminum oxide, but may contain aluminum oxide as a main component and other ceramics or the like mixed therein. The content is preferably 70% or more.

  The average reflectance with respect to the visible light region on the ground surface of the white module substrate 22 is 80% or more, and more preferably 85% or more and 99% or less. Therefore, the module substrate 22 has similar light for blue light having a specific emission wavelength of 440 nm to 460 nm emitted by a blue LED described later and yellow light having a specific emission wavelength of 470 nm to 490 nm emitted by a phosphor described later. Exhibits reflective performance.

  As shown in FIG. 3, the module substrate 22 has a substantially rectangular shape that is slightly smaller than the module installation portion 12. As shown in FIG. 4 and the like, the four corners of the module substrate 22 are rounded. The thickness of the module substrate 22 is thinner than the depth of the module installation part 12 as shown in FIG. Both surfaces of the module substrate 22 are flat surfaces made parallel to each other, and one of the surfaces is used as a component mounting surface 22a that also serves as a light reflecting surface.

  The positive electrode wiring pattern 25 and the negative electrode wiring pattern 26 are provided on the component mounting surface 22a.

  Specifically, as shown in FIG. 5 and the like, the positive electrode wiring pattern 25 is formed to have a positive electrode pattern base portion 25a and a wire connection portion 25b. The wire connecting portion 25b is formed to extend straight. The positive electrode pattern base portion 25a and the wire connection portion 25b are substantially parallel to each other and are integrally continuous via an oblique pattern portion. A positive electrode power supply pad portion, for example, a first positive electrode pad portion 25c, and a second positive electrode pad portion for connecting components, that is, a solder pad portion 25d, are integrally projected on the positive electrode pattern base portion 25a. The two corners on the tip side of the solder pad portion 25d are both chamfered by rounding or slanting as shown in FIG. 7 in order to facilitate the spread of the solder to the corner. Preferably it is.

  The negative electrode wiring pattern 26 includes a negative electrode pattern base portion 26a, a first wire connection portion 26b, an intermediate pattern portion 26c, and a second wire connection portion 26d. This wiring pattern 26 is provided so as to surround the wiring pattern 25 for the positive electrode.

  That is, the negative electrode pattern base 26a is provided adjacent to the positive electrode pattern base 25a of the wiring pattern 25 with a predetermined insulation distance A (see FIG. 5). For example, a first negative electrode pad portion 26e protrudes integrally from the negative electrode pattern base portion 26a as a negative electrode power supply pad portion provided side by side with the first positive electrode pad portion 25c. The first wire connecting portion 26b is integrally continuous so as to be bent about 90 ° with respect to the negative electrode pattern base portion 26a. The first wire connection portion 26b is provided substantially parallel to the wire connection portion 25b by forming a first element disposition space S1 between the wire connection portion 25b of the wiring pattern 25. Here, “substantially parallel” includes a parallel form as shown in FIG. 5, a slightly inclined form with respect to the wire connecting portion 25 b, a slightly curved form, and the like.

  The intermediate pattern portion 26c is provided integrally and continuously so as to be bent about 90 ° with respect to the first wire connecting portion 26b. The leading end of the wire connecting portion 25b (the end opposite to the positive electrode pattern base portion 25a) is adjacent to the intermediate portion in the longitudinal direction of the intermediate pattern portion 26c.

  The second wire connecting portion 26d is provided integrally and continuously so as to be bent by approximately 90 ° with respect to the intermediate pattern portion 26c. Thereby, the second wire connecting portion 26d is provided substantially parallel to the wire connecting portion 25b by forming the second element disposition space S2 between the wire connecting portion 25b of the wiring pattern 25 and the second element connecting space 25b. Here, “substantially parallel” includes a parallel form as shown in FIG. 5, a slightly inclined form with respect to the wire connecting portion 25b, a slightly curved form, and the like.

  Therefore, the negative electrode wiring pattern 26 is provided so as to surround the positive electrode wiring pattern 25 from three directions. The first wire connecting portion 26b and the second wire of the negative wiring pattern 26 are bordered by the wire connecting portion 25b of the wiring pattern 25 disposed in the center of the region surrounded by the negative wiring pattern 26. The connecting portions 26d are arranged symmetrically.

  A second negative electrode pad portion for connecting components, that is, a solder pad portion 26f, is integrally provided continuously at the tip of the second wire connecting portion 26d so as to correspond to the solder pad portion 25d. The solder pad portion 26f is separated from the solder pad portion 25d. The two corners on the tip side of the solder pad portion 26f are both chamfered by rounding or slanting as shown in FIG. 7 in order to facilitate the spread of the solder to the corner. It is preferable.

  An intermediate pad 27 that is located between the solder pad portion 25d of the wiring pattern 25 and the solder pad portion 26f of the wiring pattern 26 and forms an intermediate wiring pattern for component connection is formed on the component mounting surface 22a. The intermediate pad 27 is substantially rectangular, and both end portions in the longitudinal direction thereof are used as solder pad portions adjacent to the solder pad portion 25d or 26f. The four corners of the intermediate pad 28 are preferably chamfered, for example, rounded or slanted as shown in FIG. 7 in order to facilitate the spread of solder to these corners.

  The wiring pattern 25 may be used for the negative electrode and the wiring pattern 26 may be used for the positive electrode. In this case, “positive electrode” or “positive electrode” in the above description is read as “for negative electrode” or “negative electrode” and “negative electrode” “For” or “negative electrode” may be read as “for positive electrode” or “positive electrode”.

  Further, lighting inspection pads 28 and 29 for lighting confirmation test, temperature inspection pad 31 for temperature measurement, and mounting pad 33 for fixing components are provided on the component mounting surface 22a.

  That is, the lighting inspection pad 28 is provided via a pattern portion 28a that branches from the positive electrode pattern base portion 25a of the positive electrode wiring pattern 25 and protrudes integrally. Similarly, the lighting inspection pad 29 is provided via a pattern portion 29a that branches from the negative electrode pattern base portion 26a of the negative electrode wiring pattern 26 and protrudes integrally.

  The temperature inspection pad 31 is provided in the vicinity of the lighting inspection pad 29 and the negative wiring pattern 26 independently of each other without having an electrical connection relationship therewith. A thermocouple is connected to the temperature inspection pad 31 so that the temperature of the light emitting module 21 can be measured. A pair of mounting pads 33 are formed, and these are provided between the lighting inspection pads 28 and 29.

  The alignment mark 35 includes a wire connecting portion 25b, a first element disposing space S1 and a second element disposing space S2 on both sides thereof, a first wire connecting portion 26b adjacent to the first element disposing space S1, and a second A plurality of second wire connecting portions 26d adjacent to the element arrangement space S2 are provided on both sides of the second wire connecting portion 26d. Therefore, a part of the alignment mark 35 is provided in a line along the longitudinal direction of the first wire connection part 26b at a predetermined interval, and the other alignment marks 35 are similarly connected to the second wire at a predetermined interval. It is provided in a line along the longitudinal direction of the portion 26d.

  The wiring patterns 25 and 26, the intermediate pad 27, the lighting inspection pads 28 and 29, the mounting pad 33, and the alignment mark 35 are all formed of, for example, a single layer containing silver as a main component. It is provided by printing on the component mounting surface 22a by printing (first manufacturing process). In addition, it can replace with printing and can also provide by plating.

The first protective layer 37 and the second protective layer 38 are electrically insulating, for example, made of glass, and have a color that is distinct from the background color of the module substrate 22, for example, white, and is clearly black. Therefore, a material in which a black pigment is mixed with SiO ₂ which is a main component of these protective layers is used. The first protective layer 37 and the second protective layer 38 are provided on the component mounting surface 22a by printing, for example, screen printing (second manufacturing process).

  As a result of this printing, the first protective layer 37 has a portion excluding the wire connection portion 25b of the wiring pattern 25 and the first wire connection portion 26b and the second wire connection portion 26d of the wiring pattern 26 as shown in FIG. It is attached to the removed part.

  Specifically, the first protective layer 37 includes the first positive electrode pad portion 25c and the solder pad included in the portion outside the sealing member of the wiring pattern 25 that is not sealed with the sealing resin 57 described later. It is applied to the positive electrode pattern base 25a except for the portion 25d, and is also applied to the pattern portion 28a except for the lighting inspection pad 28.

  Further, the first protective layer 37 is a negative electrode pattern base portion excluding the first negative electrode pad portion 26e included in the portion of the wiring pattern 26 that is not sealed with the sealing resin 57 described later. 26a. Moreover, the first protective layer 37 is also applied to a gap portion that secures an insulation distance A between the positive electrode pattern base portion 25a and the negative electrode pattern base portion 26a, and the pattern portion except for the lighting inspection pad 29. It is also attached to 29a. In addition, the first protective layer 37 is a solder pad portion of the second wire connection portion 26d included in the portion of the wiring pattern 26 that is not sealed with the sealing resin 57 to be described later. It is attached to the end on the 26f side except for the solder pad portion 26f, and is also attached to the intermediate pad 27 except for both ends of the intermediate pad 27 forming the solder pad portion.

  As shown in FIG. 6 and the like, the first protective layer 37 has a solder pad portion 25d and a first opening 37a in which one end portion of the intermediate pad 27 adjacent to the solder pad portion 25d is disposed. 26f and a second opening 37b in which the other end portion of the intermediate pad 27 adjacent thereto is disposed.

  Each of the first opening 37a and the second opening 37b has a long hole shape, and the first corner C1 to the fourth corner C4 are formed in an arc as shown in FIG. An edge f1 extending between the first corner C1 and the second corner C2 adjacent in the short direction perpendicular to the longitudinal direction of the first opening 37a and the second opening 37b, and similarly a third corner adjacent in the short direction. Edges f2 extending between the part C3 and the fourth corner part C4 are linear and parallel to each other. At the same time, the edge f3 extending between the first corner C1 and the third corner C3 adjacent in the longitudinal direction of the first opening 37a and the second opening 37b, and the second corner C2 and the second corner C2 adjacent in the longitudinal direction as well. An edge f4 extending over the four corners C4 is also linear and parallel to each other. Accordingly, both the first opening 37a and the second opening 37b are formed in a long hole shape in which the four corners C1 to C4 are rounded.

  The edge f1 may be an edge formed by a circular arc continuous to the first corner C1 and the second corner C2. Similarly, the edge f2 is continuous to the third corner C3 and the fourth corner C4. It may be an edge formed by a circular arc. Furthermore, the space | interval between the edge f3 and the 4 edge f4 is formed wider than the width | variety of the both ends of the solder pad part 25d, the solder pad part 26f, and the intermediate | middle pad 27, for example. Further, the four corners of the first opening 37a and the second opening 37b can be formed obliquely.

  As shown in FIG. 6, the second protective layer 38 is attached to substantially the entire intermediate pattern portion 26 c included in the outer portion of the sealing member that is not sealed with the sealing resin 57 described later of the wiring pattern 26. This second protective layer 38 is also applied to the outer portion of the sealing member as described above, with the size of the second protective layer 38 limited to the size of the periphery of this portion.

  The first identity mark 41 to the fourth identity mark 44 are arranged around the outside of a sealing resin 57 to be described later and are printed on the component mounting surface 22a of the module substrate 22 by, for example, screen printing. (Third manufacturing process). Further, by this printing, polarity indications such as “+” and “−” are also provided on the component mounting surface 22a. The first identity mark 41 is a company name indicating the manufacturer, the second identity mark 42 is a product name, the third identity mark 43 is a product number, and the fourth identity mark 44 is It is a two-dimensional barcode (QR code) showing information about the light emitting module 21.

  The first identity mark 41 to the fourth identity mark 44 are printed in a color different from that of the module substrate 22, for example, from the same printing material as the first protective layer 37 and the second protective layer 38. Therefore, it is black and is provided on the peripheral portion of the module substrate 22 by printing simultaneously with the first protective layer 37 and the second protective layer 38.

  The plurality of semiconductor light emitting elements 45 are provided with a compound semiconductor that forms a semiconductor light emitting layer on a translucent element substrate made of, for example, sapphire glass, and various types of structures including a pair of element electrodes provided on the light emitting layer. Although a light emitting element can be used, it is also possible to use a semiconductor light emitting element that emits ultraviolet light or green light. For each of these semiconductor light emitting elements 45, for example, a blue LED made of bare chip that emits blue light is used.

  Since light emission of an LED is realized by passing a forward current through a pn junction of a semiconductor, the LED is a solid element that directly converts electric energy into light. A semiconductor light emitting element that emits light based on such a light emission principle has an energy saving effect as compared with an incandescent bulb that inclines a filament to a high temperature by energization and emits visible light by its thermal radiation.

  Half of the semiconductor light emitting elements 45 are directly mounted on the module substrate 22 in the first element disposition space S1. This mounting is realized by bonding the element substrate to the component mounting surface 22a using a transparent die bond material, and the plurality of semiconductor light emitting elements 45 mounted in the first element disposition space S1 are aligned vertically and horizontally. Arranged in a matrix. Similarly, the remaining semiconductor light emitting elements 45 are mounted directly on the module substrate 22 in the second element arrangement space S2. This mounting is also realized by adhering the element substrate to the component mounting surface 22a using a transparent die bond material, and the plurality of semiconductor light emitting elements 45 mounted in the second element arrangement space S2 are also aligned vertically and horizontally. Arranged in a matrix.

  The plurality of semiconductor light emitting elements 45 disposed in the first element disposition space S1 and the plurality of semiconductor light emitting elements 45 disposed in the second element disposition space S2 are provided symmetrically with respect to the wire connection portion 25b. It has been.

  The semiconductor light emitting elements 45 arranged in a line in the direction in which the wire connection part 25 b of the wiring pattern 25 and the first wire connection part 26 b of the wiring pattern 26 are arranged are connected in series by a bonding wire 47. The semiconductor light emitting elements 45 arranged at one end of the element rows connected in series in this way are connected to the wire connecting portion 25b by the bonding wires 48. At the same time, the semiconductor light emitting element 45 disposed at the other end of the element row is connected to the first wire connecting portion 26b by a bonding wire 49.

  Similarly, the semiconductor light emitting elements 45 arranged in a row in the direction in which the wire connection portion 25 b of the wiring pattern 25 and the second wire connection portion 26 d of the wiring pattern 26 are arranged are connected in series by a bonding wire 50. . The semiconductor light emitting element 45 arranged at one end of the element rows thus connected in series is connected to the wire connecting portion 25b by the bonding wire 51. At the same time, the semiconductor light emitting element 45 disposed at the other end of the element row is connected to the second wire connecting portion 26d by the bonding wire 52 (fourth manufacturing process). The bonding wires 47 to 52 are all made of fine metal wires, preferably gold wires, and are provided by wire bonding.

  By electrically connecting a plurality of semiconductor light emitting elements 45 mounted on the module substrate 22 as described above, a COB (Chip On Board) type light emitting module 21 is configured. Due to the electrical connection, the plurality of semiconductor light emitting elements 45 provided in the element disposition spaces S1 and S2 are electrically connected to, for example, 12 element rows formed by connecting 7 semiconductor light emitting elements 45 in series. Is an array connected in parallel.

  The alignment marks 35 are respectively disposed on the extended lines of the element rows in series. Then, with reference to the left and right (in the drawing) alignment marks 35 positioned on the extension line, the semiconductor light emitting element 45 is mounted by a mounting machine on a straight line passing therethrough.

  As shown in FIG. 4, the frame 55 has, for example, a square ring shape, and each of the wire connecting portions 25b, 26b, and 26d, the plurality of semiconductor light emitting elements 45, and the bonding wires 47 to 52 are housed inside the frame. Mounted on the surface 22a. The frame 55 is preferably made of a white synthetic resin. The frame 55 is attached to part of the first protective layer 37 and part of the second protective layer 38.

  As the sealing resin 57, a translucent resin material such as an epoxy resin, a urea resin, or a silicone resin can be used, but translucent glass can be used as a sealing member instead of the resin. The sealing resin 57 is filled in the frame 55 and seals the wire connecting portions 25b, 26b, 26d, the plurality of semiconductor light emitting elements 45, and the bonding wires 47 to 52 in an embedded state, It is provided on the module substrate 22 (fifth manufacturing process). A region covered with the sealing resin 57 in the component mounting surface 22a is used as a light reflecting surface. The sealing resin 57 is made of a transparent silicone resin or the like mixed with a phosphor (not shown), and is translucent and gas permeable. A yellow phosphor that emits yellow light when excited by blue light emitted from the semiconductor light emitting element 45 is used as the phosphor. In order to obtain white illumination light under the condition using an LED that emits ultraviolet light to the semiconductor light emitting element 45, red, blue, and yellow phosphors may be used.

  White light is formed by mixing the blue light and yellow light having a complementary color to the blue light, and the white light is emitted from the surface of the sealing resin 57 in the light use direction. Therefore, the light emitting surface 57 a of the light emitting module 21 is formed by the surface of the sealing resin 57, that is, the light emitting surface. The size of the light emitting surface 57 a is defined by the frame 55.

  When the area of the silver portion covered with the sealing resin 57 is C and the area of the light emitting surface 57a is D, the occupation ratio of the area C to the area D is set to 5% or more and 40% or less. . The portions covered with the sealing resin 57 of the wiring patterns 25 and 26 are the wire connection portions 25b, 26b, and 26d.

  Alternatively, the sealing resin 57 may be provided by providing a mold member corresponding to the frame 55 and providing the sealing resin 57 therein, and then removing the mold member from the module substrate 22.

  As shown in FIG. 4, one connector 61 and two capacitors 65 made of surface-mounted components are mounted on the component mounting surface 22a (sixth manufacturing process).

  That is, the connector 61 has a two-pin type configuration having a first terminal pin 61a and a second terminal pin 61b protruding from one side surface thereof. The connector 61 is soldered to the mounting pad 33, thereby being disposed between the lighting inspection pads 28 and 29. At the same time, the first terminal pin 61a is attached to the first positive electrode pad portion 25c, and the second terminal pin 61b is attached to the first negative electrode pad portion 26e. The connector 61 is connected with an insulation coated electric wire for direct current power supply connected to a power supply device (not shown). As a result, power can be supplied to the light emitting module 21 via the connector 61.

  As shown in FIGS. 8 and 9, the two capacitors 65 are formed by providing electrodes 67 at both ends in the longitudinal direction of a rectangular parallelepiped component main body 66. The size of the electrode 67 is smaller than the size of each end portion of each solder pad portion 25d, 26f and intermediate pad 27 as shown in FIG.

  One of the two capacitors 65 is soldered to one end portion of the solder pad portion 25d and the intermediate pad 27 which are close to each other in a pair in the first opening 37a of the first protective layer 37, Arranged over these. Similarly, the other of the two capacitors 65 is connected to the other end portion of the solder pad portion 26f and the intermediate pad 27 (solder) in the second opening 37b of the first protective layer 37 that are close to each other in a pair. Soldered to the pad portion) and disposed over them.

  The solder in which one of the two capacitors 65 is soldered to the pair of solder pads is represented by reference numeral 68 in FIG. The solder 68 shown in FIG. 9 is dammed at the edge of the first opening 37a by the first protective layer 37 functioning as a solder resist, and the solder pad portion disposed in the first opening 37a. The entire surface of 25d and the entire surface of one end portion (solder pad portion) of the intermediate pad 27 are covered, and the solder pad portion and the electrode 67 of the capacitor 65 are soldered. Similarly, the solder obtained by soldering the other of the two capacitors 65 is blocked by the edge of the second opening 37b because the first protective layer 37 functions as a solder resist, and the second opening 37b. Covering the entire surface of the solder pad portion 26 f disposed inside and the entire surface of the other end portion (solder pad portion) of the intermediate pad 27, the paired solder pad portion and the electrode 67 of the capacitor 65 are connected. Soldering. The solder 68 is supplied to the solder pad portion by using a dispenser or is supplied by printing, and is provided by soldering the capacitor 65 by being melted by a reflow furnace.

  Furthermore, the first separation distance E (see FIG. 8) between the electrode 67 of the soldered capacitor 65 and the corners C1 to C4 of the first opening 37a or the second opening 37b adjacent thereto is as follows. Shorter than the second separation distance G (see FIG. 8) along the center line of the capacitor 65 passing through the electrode 67 to the edges f1 and f2 of the first opening 37a or the edges f1 and f2 of the second opening 37b. Yes.

  In a normal lighting state in which direct current is supplied to each semiconductor light emitting element 45, no current flows through the capacitor 65. However, for example, when an alternating current flows due to noise such as a surge voltage superimposed, a current flows through the capacitor 65, the wiring patterns 25 and 26 are short-circuited, and an alternating current is supplied to each semiconductor light emitting element 45. Thus, each semiconductor light emitting element 45 is prevented from abnormally emitting light. Note that a Zener diode can be used instead of the capacitor as a surface-mounted component for preventing abnormal light emission.

  As shown in FIG. 10, the light emitting module 21 having the above-described configuration is attached to the apparatus base 11 by bringing the back surface of the module substrate 22, that is, the surface opposite to the component mounting surface 22 a into close contact with the bottom surface 12 a of the module installation portion 12. It is supported. Thereby, the light emitting module 21 is supported by the apparatus base 11 so that heat can be radiated from the module substrate 22 to the module installation unit 12. In a state where the light emitting module 21 supported in this manner is attached to the lamp body 4, the light emitting surface 57 a faces the light transmitting plate 5.

  In order to support the module, a plurality of, for example, two metal pressing plates 71 are screwed to the apparatus base 11 as shown in FIGS. The front ends of these presser plates 71 are opposed to the peripheral portion of the module substrate 22, and a metal spring 72 that presses the peripheral portion of the module substrate 22 is attached to the front end portion. The state in which the back surface of the module substrate 22 is in close contact with the bottom surface 12a is maintained by the spring force of the springs 72.

  When power is supplied to the road light 1 having the above-described configuration, the plurality of semiconductor light emitting elements 45 included in the light emitting module 21 emit light at the same time, so that white light emitted from the light emitting surface 57a is transmitted through the light transmitting plate 5. Directly transmitted or reflected by the inner surface of the reflector 15 and then transmitted through the light-transmitting plate 5 to illuminate a road having illumination symmetry. With this illumination, the light reflected by the first reflecting plate 15a and the second reflecting plate 15b made of a plane mirror is irradiated mainly in the longitudinal direction of the road without substantially spreading. At the same time, the light reflected by the third reflecting plate 15c and the fourth reflecting plate 15d made of a curved mirror is mainly irradiated in the width direction of the road with the irradiation angle with respect to the width direction of the road being controlled.

  In such illumination, light emitted in the light extraction direction from the light emitting surface 57a is directly transmitted through the sealing resin 57 from the semiconductor light emitting element 45, and is emitted from the phosphor in the sealing resin 57 to pass through the sealing resin 57. In addition to the directly transmitted light, the light is incident on the component mounting surface 22a through the element substrate and the die bonding material of the semiconductor light emitting element 45, and is reflected by the component mounting surface 22a and transmitted through the sealing resin 57, and Light emitted from the phosphor and incident on the component mounting surface 22 a through the sealing resin 57 and reflected by the component mounting surface 22 a and transmitted again through the sealing resin 57 and sealed with the sealing resin 57 Is incident on a part of the wiring patterns 25 and 26 mainly containing silver (that is, the wire connecting portion 25b, the first wire connecting portion 26b, and the second wire connecting portion 26d). Contains the light transmitted through the sealing resin 57 is again reflected by the portion.

  Thus, the light reflection region of the module substrate 22 covered with the sealing resin 57 that reflects the incident light in the light extraction direction, and each of the wiring patterns 25 and 26 disposed in this region are sealed. Covered with resin 57 and sealed. At the same time, the remaining portions of the wiring patterns 25, 26, that is, the outer portion of the sealing member provided outside the sealing resin 57 without being sealed with the sealing resin 57, are attached to the first protection. The layer 37 or the second protective layer 38 is sealed.

  Thereby, since both the wiring patterns 25 and 26 containing silver as a main component are suppressed from being sulfurized by sulfur components in the atmosphere, both the wiring patterns 25 and 26 forming paths for supplying power to the respective semiconductor light emitting elements 45 are formed. However, deterioration and high resistance can be suppressed.

  Furthermore, the solder pad portion 25 d of the wiring pattern 25 to which the capacitor 65 is soldered, the solder pad portion 26 f of the wiring pattern 26, and the end portion (solder pad portion) of the intermediate pad 27 are the first protection layer 37. Although disposed in the opening 37a or the second opening 37b and not attached to the first protective layer 37, deterioration of these solder pad portions (including the end portion of the intermediate pad 27) due to sulfidation is caused. It can be suppressed for the following reasons.

  That is, the wiring patterns 25, 26 are formed by the longitudinal ends of the first openings 37 a and the longitudinal ends of the second openings 37 b of the first protective layer 37 attached to the wiring patterns 25, 26. The shape of the solder pad portion is defined, and the four corner portions C1 to C2 of the first opening 37a and the second opening 37b are formed in an arc shape.

  With this configuration, the edges f1 and corners C1 and C2 at the ends in the longitudinal direction of the first opening 37a and the second opening 37b, and the edges f2 and corners C3 and C4 are provided so as to form an angle of a right angle or less. There is no. In addition, the first separation distance E between the corner of the electrode 67 of the capacitor 65 soldered to the solder pad portion and the corners C1 to C4 of the first opening 37a and the second opening 37b can be shortened.

  As a result, when soldering is performed using a reflow furnace, the melted solder 68 is blocked by the edges f1 and f2 of the first opening 37a and the second opening 37b as shown in FIG. The openings 37a and 37b also spread smoothly to the corners C1 to C4, and are surely spread over the entire surface of the solder pad portion. Moreover, since the first separation distance E is shorter than the second separation distance G along the center line of the capacitor 65 passing through the electrode 67 from the electrode 67 to the edge f1 or the edge f2 adjacent to the electrode 67, the solder 68 is connected to each solder pad. It will be spread more smoothly and reliably over the entire surface of the part.

  As described above, since the solder 68 is provided so as to cover the entire surface of the solder pad portion and a part of the solder pad portion mainly composed of silver is not exposed to the atmosphere, the first opening 37a or the second opening is not provided. The sulfurization reaction at the solder pad portion disposed in 37b can be prevented. For this reason, it is possible to suppress the deterioration of both the wiring patterns 25 and 26 and the increase in resistance.

  Further, as described above, the solder 68 is surely spread over the entire surface of the solder pad portion, and the electrode 66 of the capacitor 65 is soldered to the solder pad portion, so that the reliability of soldering to the capacitor 65 is improved. It is possible. In addition, since a part of the solder pad portion is not exposed, the occurrence of silver migration is suppressed, and accordingly, the solder pad portions arranged in close proximity can be prevented from being short-circuited due to silver migration.

  In the first embodiment, the number of surface mount components such as the capacitor 65 may be one. In this case, the intermediate pad 27 is omitted, and an opening in which the solder pad portion 25d of the wiring pattern 25 and the solder pad portion 26f of the wiring pattern 26 are disposed is provided in the protective layer 37, and the solder pad portions 25d, 26f are provided. It is only necessary to solder a surface mounting component such as a capacitor to the solder pad portions 25d and 26f.

  The first protective layer 37 and the second protective layer 38 are provided outside the region sealed with the sealing resin 57. Therefore, the first protective layer 37 and the second protective layer 38 do not enter the sealing region, and the light reflection area of the module substrate 22 having a size corresponding to the area of the sealing resin 57 is not reduced. At the same time, although the first protective layer 37 and the second protective layer 38 are black different from the background color forming the light reflection surface of the module substrate 22, the first protective layer 37 and the second protective layer 38 The light reflection performance on the module substrate 22 side does not deteriorate due to light absorption by the protective layer 38.

  Further, in the light emitting module 21 of Example 1, the module substrate 22 having the component mounting surface 22a is made of white ceramics as described above, and the average reflectance thereof is 80% or more. The incident light, that is, the blue light emitted from the blue LED that forms the semiconductor light emitting element 45 and the yellow light emitted from the phosphor and emitted from the phosphor of 470 nm to 490 nm, is converted into the light in the road direction, in other words, the light. Can be efficiently reflected in the direction of taking out.

  Since the module substrate 22 having the component mounting surface 22a that reflects light is made of white ceramics and uses the ground surface as the component mounting surface 22a, the reflection performance of the module substrate 22 is as follows. Regardless of the elapsed time from the start of use of the light emitting module 21, it is maintained constant.

  Furthermore, the reflection of light on the module substrate 22 side is not limited to the component mounting surface 22a, but the wire connection portion 25b of the wiring pattern 25 sealed with the sealing resin 57 and the first wire connection portion of the wiring pattern 26. 26b and the second wire connection portion 26d, the wire connection portions 25b, 26b, and 26d are darkened as the elapsed time from when the road lamp 1 is installed becomes longer, and the light reflection thereof The performance gradually decreases.

  However, in the light emitting module 21 configured as described above, the area occupancy ratio of the wire connection portions 25b, 26b, and 26d mainly composed of silver with respect to the area of the light emitting surface 57a is specified to be 40% or less. In other words, the reflection area on the component mounting surface 22a is ensured to exceed 60% of the area of the light emitting surface 57a.

  By defining the area occupancy rate, it is possible to limit the influence of the decrease in the light reflection performance accompanying the progress of the blackening of the wire connection portions 25b, 26b, and 26d on the light reflection performance of the entire light emitting module 21. Therefore, according to the light emitting module of Example 1, it is possible to moderate the decrease in the luminous flux maintenance factor of the light emitting module 21. In other words, the deterioration of the light reflection performance in the reflection region covered with the light emitting surface 57a is slow. As a result, the light extraction efficiency is maintained at a high level, so that the energy saving effect can be promoted.

  As the decrease in the luminous flux maintenance factor is slow as described above, it is possible to provide the road lamp 1 that takes a long time for the light emitting module 21 as the light source to reach a specified life, for example, the luminous flux maintenance factor reaches 70%. Is possible. In other words, when the area occupancy of the sealed silver portion with respect to the light emitting surface 57a is 40% or less, even when the road lamp (lighting fixture) 1 is used beyond the recommended life, Regardless of the blackening of the portion, the luminous flux maintenance factor of the light emitting module 21 can be maintained at 70% or more. Note that the recommended life as a guide for replacement of the road lamp 1 is defined when the luminous flux maintenance factor reaches 70%.

  In addition, when the area occupation ratio with respect to the light emitting surface 57a of the sealed silver portion exceeds 40%, the influence on the light reflecting performance of the entire light emitting module 21 due to the progress of blackening of the silver portion becomes too large. Accordingly, the decrease in the luminous flux maintenance factor of the light emitting module 21 is accelerated, and the time required for the luminous flux maintenance factor to reach 70% is shortened.

  Further, the area occupation ratio of the wire connection portions 25b, 26b, and 26d of the wiring patterns 25 and 26 sealed with the sealing resin 57 to the light emitting surface 57a is 5% or more. Thereby, the width of the wire connecting portions 25b, 26b, and 26d can be formed to be wide to some extent so as not to hinder the wire bonding of the bonding wires 48, 49, 51, and 52 to these portions. Accordingly, it is possible to prevent manufacturing problems.

  22 ... Module substrate (circuit board), 25 ... Positive electrode wiring pattern, 25d ... Solder pad portion, 26 ... Negative electrode wiring pattern, 26f ... Solder pad portion, 27 ... Intermediate pad (solder pad portion), 37 ... First Protective layer, 37a ... 1st opening, 37b ... 2nd opening, C1-C ... Corner of opening, f1, f2 ... Edge of opening, 65 ... Capacitor (surface mount component), 67 ... Electrode, 68 ... Solder, E ... 1st separation distance, G ... 2nd separation distance

Claims (2)

A circuit board;
A wiring pattern mainly composed of silver provided on the circuit board having a solder pad portion;
The opening has a long hole shape and is attached to the wiring pattern, and the four corners of the opening are formed in a circular arc or obliquely, and the solder pad portions are disposed at both ends in the longitudinal direction of the opening. An electrically insulating protective layer,
A surface mount component having a pair of electrodes and disposed over the solder pad portion in the opening;
Solder that is dammed at the edge of the opening and covers the entire surface of the solder pad portion, and solders the electrode to the solder pad portion;
A circuit board comprising:   A first separation distance between the electrode and a corner of the opening adjacent thereto is a second distance along a center line of the surface mount component passing through the electrode from the electrode to an edge of the opening adjacent to the electrode. The circuit board according to claim 1, wherein the circuit board is shorter than a separation distance.

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