JP2012099335A - Led bulb - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED bulb capable of achieving high brightness and light-emitting uniformity.SOLUTION: The LED bulb A includes: a substrate 1 which has a main face 1c and is composed of ceramics; a plurality of LED chips mounted on the main face of the substrate 1; a heat-dissipating member 5 which supports the substrate 1, and in which heat from the LED chips are transmitted via the substrate; a globe 3 which covers the plurality of LED chips, and transmits light from the plurality of LED chips; and a base 7 mounted on a side opposite to the globe 3 against the heat dissipating member 5.

Description

  The present invention relates to an LED bulb.

  As an alternative to so-called incandescent bulbs, LED bulbs mounted with LED chips are beginning to spread. LED bulbs have advantages such as power saving and long life over incandescent bulbs.

  FIG. 27 shows an example of a conventional LED bulb (see, for example, Patent Document 1). The LED bulb X shown in the figure includes an LED module 91, a cover 92, a heat radiating member 93, and a base 95. The LED module 91 is a light emitting means of the LED bulb X, and has an LED chip (not shown) built therein. The cover 92 transmits light from the LED module 91 and has a substantially spherical shape. The heat radiating member 93 is for radiating the heat from the LED module 91, and is made of, for example, aluminum. The heat dissipating member 93 is formed with a plurality of fins 94 for enhancing the heat dissipating effect. The base 95 is a part for attaching the LED bulb X to a lighting fixture for an incandescent bulb.

  However, the LED module 91 includes a lead or a substrate (both not shown) on which the LED chip is mounted. For this reason, the size of the LED module 91 is significantly larger than the LED chip. When trying to increase the mounting density of the plurality of LED modules 91, the LED modules 91 interfere with each other. Therefore, there has been a problem that the LED bulb X has high luminance or uniform emission.

JP 2010-56059 A

  The present invention has been conceived under the circumstances described above, and it is an object of the present invention to provide an LED bulb capable of achieving high luminance or uniform emission.

  The LED bulb provided by the present invention has a main surface and is made of a ceramic, a plurality of LED chips mounted on the main surface of the substrate, and supports the substrate, and from the LED chip. A heat dissipating member that transmits heat through the substrate, a globe that covers the plurality of LED chips and transmits light from the plurality of LED chips, and a side opposite to the globe with respect to the heat dissipating member And an attached base.

  In a preferred embodiment of the present invention, a wiring pattern that is electrically connected to the plurality of LED chips is formed on the substrate, and a reflective layer that covers at least a part of the wiring pattern is provided.

  In a preferred embodiment of the present invention, the reflective layer is white.

  In a preferred embodiment of the present invention, the LED chip has a submount substrate made of Si and a semiconductor layer mounted on the submount substrate, and the submount substrate is positioned on the substrate side. So that the reflective layer covers at least a part of the side surface of the submount substrate facing a direction perpendicular to the normal direction of the main surface; and It is made of a material having a higher reflectance than the submount substrate.

  In a preferred embodiment of the present invention, the reflective layer covers all of the side surfaces of the submount substrate.

  In a preferred embodiment of the present invention, the reflective layer exposes all of the semiconductor layer.

  In a preferred embodiment of the present invention, a Zener diode is built in the submount substrate to avoid applying an excessive reverse voltage to the semiconductor layer.

  In a preferred embodiment of the present invention, a translucent resin that covers the plurality of LED chips and transmits light from the plurality of LED chips is provided.

  In a preferred embodiment of the present invention, the translucent resin is a fluorescent material that emits light having a wavelength different from that of the light from the plurality of LED chips when excited by light from the plurality of LED chips. Contains.

  In a preferred embodiment of the present invention, a reflector is provided which is attached to the substrate and has a plurality of openings each having an inner surface surrounding one or more LED chips.

  In a preferred embodiment of the present invention, the inner surface is inclined so as to move away from the LED chip in the in-plane direction of the main surface as the distance from the main surface increases in the normal direction of the main surface.

  In a preferred embodiment of the present invention, the plurality of openings includes one that houses the plurality of LED chips.

  In a preferred embodiment of the present invention, the plurality of openings all accommodate a plurality of the LED chips.

  In a preferred embodiment of the present invention, the plurality of openings have a rectangular shape when viewed in the normal direction of the main surface.

  In a preferred embodiment of the present invention, the plurality of openings are hexagonal when viewed in the normal direction of the main surface.

  In a preferred embodiment of the present invention, the plurality of openings are concentric rings in the normal direction of the main surface.

  In a preferred embodiment of the present invention, the mounting density of the plurality of LED chips becomes denser from the center to the periphery of the substrate.

  In a preferred embodiment of the present invention, the heat dissipating member has a cylindrical portion whose axial direction is the normal direction of the main surface, is accommodated in the cylindrical portion, and the plurality of A power supply unit that supplies power to the LED chip is provided, and the substrate is formed with two through holes, and the power supply unit is a core wire that is inserted through the through hole from the side opposite to the main surface. Two cables having

  In a preferred embodiment of the present invention, the substrate is formed with a wiring pattern including two terminal pads separately surrounding each through hole, and protrudes from the substrate to the main surface side of the core wire. These parts are joined to the terminal pads by soldering.

  In a preferred embodiment of the present invention, a translucent resin that covers the plurality of LED chips is provided, and the two through holes are arranged with the translucent resin interposed therebetween.

  In a preferred embodiment of the present invention, the substrate has a long rectangular shape, and has a light emitting region in which the translucent resin is formed and a non-light emitting region adjacent to the light emitting region. The through hole is arranged in the non-light emitting region.

  In a preferred embodiment of the present invention, chamfered portions are formed at the four corners of the substrate.

  In a preferred embodiment of the present invention, the light emitting region has a rectangular shape, and the four sides of the light emitting region and the four sides of the substrate are inclined with respect to each other.

  In preferable embodiment of this invention, the clip which fixes the said board | substrate is provided by giving the elastic force which presses on the said board | substrate to the direction opposite to the normal line direction of the said main surface.

  In a preferred embodiment of the present invention, a heat transfer layer in contact with the clip is formed on the main surface of the substrate.

  In a preferred embodiment of the present invention, the heat transfer layer is made of metal and separated from the wiring pattern.

  In a preferred embodiment of the present invention, the heat transfer layer is made of a highly heat conductive resin and is in contact with the wiring pattern.

  In a preferred embodiment of the present invention, the heat radiating member includes a cylindrical portion having a uniform cross-sectional shape in a plane perpendicular to an axial direction coinciding with a normal direction of the main surface, and A plurality of fins that extend outward from the shape portion and extend in the axial direction and have a constant plate thickness at the same position in the axial view.

  In preferable embodiment of this invention, the said cylindrical part is cylindrical shape.

  In a preferred embodiment of the present invention, the plurality of fins are arranged radially about the central axis of the cylindrical portion.

  In preferable embodiment of this invention, the dimension in the radial direction with respect to the said axial direction of each said fin is so large that it is close to the said LED chip.

  In a preferred embodiment of the present invention, the heat radiating member is made of aluminum.

  According to such a configuration, the interval between the LED chips can be easily reduced. Thereby, it is possible to increase the mounting density of the plurality of LED chips. Therefore, high brightness of the LED bulb can be achieved. Further, by increasing the mounting density, it is difficult to visually recognize that each of the plurality of LED chips is shining as a point light source. Thereby, the LED bulb can emit light more uniformly.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is a front view which shows an example of the LED bulb which concerns on this invention. It is sectional drawing which follows the II-II line | wire of FIG. It is sectional drawing in alignment with the III-III line | wire of FIG. 1, and a principal part expanded sectional view. It is principal part sectional drawing in alignment with the IV-IV line of FIG. It is principal part sectional drawing which shows an example of the LED chip used for the LED bulb of FIG. It is principal part sectional drawing which shows an example of the fixation structure of the board | substrate of the LED bulb of FIG. It is a top view which shows an example of the heat radiating member used for the LED light bulb of FIG. It is a front view which shows an example of the heat radiating member used for the LED bulb of FIG. It is a bottom view which shows an example of the heat radiating member used for the LED bulb of FIG. It is sectional drawing which follows the XX line of FIG. It is a front view which shows the board | substrate and electronic component of a power supply part used for the LED light bulb of FIG. It is a rear view which shows the board | substrate and electronic component of a power supply part used for the LED light bulb of FIG. It is a perspective view which shows the process of cut | disconnecting a elongate member in an example of the manufacturing method of an LED light bulb to the LED light bulb of FIG. It is a front view which shows the process of cut | disconnecting a short member in an example of the manufacturing method of an LED bulb to the LED bulb of FIG. It is a front view which shows the assembly process in an example of the manufacturing method of an LED bulb to the LED bulb of FIG. It is sectional drawing which shows the modification of the LED bulb which concerns on this invention. It is sectional drawing which shows the other modification of the LED bulb which concerns on this invention. It is principal part sectional drawing which follows the XVIII-XVIII line of FIG. It is principal part sectional drawing which shows the other modification of the LED bulb which concerns on this invention. It is sectional drawing which shows the other modification of the LED bulb which concerns on this invention. It is sectional drawing which shows the other modification of the LED bulb which concerns on this invention. It is principal part sectional drawing which follows the XXII-XXII line | wire of FIG. It is sectional drawing which shows the other modification of the LED bulb which concerns on this invention. It is sectional drawing which shows the other modification of the LED bulb which concerns on this invention. It is sectional drawing which shows the other modification of the LED bulb which concerns on this invention. It is sectional drawing which shows the other modification of the LED bulb which concerns on this invention. It is a front view which shows an example of the conventional LED bulb.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  1 to 3 show an example of an LED bulb according to the present invention. The LED light bulb A of this embodiment includes a substrate 1, a plurality of LED chips 2, a globe 3, a bracket 4, a heat radiating member 5, a power supply unit 6, and a base 7. The LED bulb A is used by being attached to a lighting fixture for an incandescent bulb as an alternative product to the incandescent bulb.

  The substrate 1 is for supporting a plurality of LED chips 2 and is made of ceramic such as alumina. As shown in FIG. 3, the substrate 1 has a substantially square shape in the present embodiment. As shown in FIGS. 2 and 3, two through holes 11 are formed in the substrate 1.

  FIG. 5 is an enlarged cross-sectional view of a main part showing the substrate 1 and the LED chip 2. As shown in the figure, a wiring pattern 12 is formed on the substrate 1. The wiring pattern 12 is made of, for example, Ag, and serves as a path for supplying power to the plurality of LED chips 2. In the present embodiment, as shown in FIG. 3, the wiring pattern 12 includes two terminal pads 13. Each terminal pad 13 surrounds each through hole 11. In the present embodiment, the two through holes 11 and the two terminal pads 13 are spaced apart from each other on both sides of the substrate 1. As shown in FIG. 5, a glass layer 10 may be formed on the substrate 1. The glass layer 10 is provided to form a smooth surface suitable for forming the wiring pattern 12.

  As shown in FIG. 5, the LED chip 2 has, for example, a structure having a submount substrate 21 made of Si and a semiconductor layer 22 in which an n-type semiconductor layer, an active layer, and a p-type semiconductor layer made of GaN are stacked. For example, it emits blue light. An electrode pad (not shown) formed on the submount substrate 21 side is formed on the semiconductor layer 22. These electrode pads are bonded to a wiring pattern (not shown) formed on the submount substrate 21. Two electrodes (not shown) are formed on the LED chip 2, and these electrodes are connected to the wiring pattern 12 by wires 23. The LED chip 2 of the present embodiment has an x-direction dimension of about 1.9 mm and a y-direction dimension of about 1.3 mm. For joining the LED chip 2 and the wiring pattern 12 (or the substrate 1), for example, an Ag paste, an epoxy resin, or an epoxy resin mixed with a filler made of a material having high conductivity is used. These bonding materials are preferable for promoting the heat dissipation effect of the LED chip 2. In the submount substrate 21, a Zener diode for preventing an excessive reverse voltage from being applied to the semiconductor layer 22 is formed.

  The LED chip 2 of the present embodiment is a so-called two-wire type, but unlike this, the so-called one-wire type LED chip 2 that can be mounted by one wire 23 or mounting without using the wire 23 is possible. A certain so-called flip chip type LED chip 2 may be used.

  As shown in FIGS. 4 and 5, the wiring pattern 12 is covered with a white resin layer 15. The white resin layer 15 corresponds to an example of the reflective layer referred to in the present invention. The white resin layer 15 is made of a material that is opaque to light from the LED chip 2 such as a white epoxy resin and has a higher reflectance than the submount substrate 21. The white resin layer 15 covers all the side surfaces of the submount substrate 21. Unlike the present embodiment, a configuration in which a part of the side surface of the submount substrate 21 is covered with the white resin layer 15 may be employed.

  The plurality of LED chips 2 are covered with a translucent resin 24. The translucent resin 24 is made of, for example, a material in which a phosphor material is mixed in a transparent epoxy resin or silicone resin. This phosphor material emits yellow light when excited by blue light emitted from the LED chip 2, for example. The yellow light and the blue light from the LED chip 2 are mixed to obtain white light. In addition, as a material of the translucent resin 24, a transparent epoxy resin or silicone resin mixed with a phosphor material that emits red light and a phosphor material that emits green light when excited by blue light is mixed. It may be used. In the present embodiment, the plurality of LED chips 2 are arranged in a matrix of 8 columns × 8 rows. The translucent resin 24 covering these LED chips 2 has a square shape in plan view.

  The globe 3 is for protecting the plurality of LED chips 2 and is made of, for example, a transparent or translucent resin. In the present embodiment, the globe 3 is a semi-ellipsoid whose outer shape has the axial direction Na as the major axis direction. As shown in FIG. 3, the outer surface 32 of the globe 3 is a very smooth surface. On the other hand, the inner surface 31 of the globe 3 is subjected to a rough surface treatment. This rough surface treatment is performed, for example, by performing a shot blasting process on a portion for forming the inner surface 31 of a mold for forming the globe 3. In addition to the inner surface 31, the outer surface 32 may be subjected to the same rough surface treatment.

  The bracket 4 is made of aluminum, for example, and has an edge portion 41 and a pedestal portion 42 as shown in FIG. The edge portion 41 has a ring shape and occupies the outer peripheral portion of the bracket 4. The edge portion 41 is configured to accommodate the lower end portion of the globe 3 therein, and facilitates the attachment of the globe 3 and the heat radiating member 5. The pedestal portion 42 is a portion at the center of the bracket 4 and is in a disk shape in the present embodiment. The substrate 1 is attached to the pedestal portion 42. The pedestal portion 42 has two through holes 43 formed therein. The substrate 1 is attached to the pedestal portion 42 with an adhesive 44 as shown in FIG. Instead of the adhesive 44, an adhesive tape may be used.

  The heat radiating member 5 is for radiating the heat from the LED chip 2, and a cylindrical portion 51, a plurality of fins 52, and a pedestal portion 53 are formed. The heat dissipating member 5 of the present embodiment is made of, for example, aluminum, and is formed by using extrusion as described later.

  The cylindrical portion 51 has a cylindrical shape having a central axis extending in the axial direction Na, and is cylindrical in this embodiment. The cylindrical portion 51 has a length over the entire region in the axial direction Na of the heat dissipation member 5. The cylindrical portion 51 has the same cross-sectional shape in a plane perpendicular to the axial direction Na at any location in the axial direction Na.

  The plurality of fins 52 are formed radially from the cylindrical portion 51 along the radial direction Nd around the central axis of the cylindrical portion 51. As clearly shown in FIGS. 7, 9, and 10, each fin 52 has the same thickness at any position in the axial direction Na in the portion where the position in the axial direction Na is the same. . In addition, gaps between adjacent fins 52 exist across both ends of the plurality of fins 52 in the axial direction Na. For example, portions that seal these gaps are not formed in the heat dissipation member 5. As clearly shown in FIGS. 2 and 8, the dimension of each fin 52 in the radial direction Nd is larger as it is closer to the LED chip 2 in the axial direction Na.

  The pedestal 53 is provided at one end of the heat dissipation member 5 in the axial direction Na and slightly protrudes from the plurality of fins 52 in the axial direction Na. As shown in FIGS. 7 to 9, the pedestal portion 53 is formed such that the tubular portion 51 and portions of the plurality of fins 52 near the central axis in the radial direction Nd extend in the axial direction Na. Has been. The pedestal 53 is in contact with the pedestal 42 of the bracket 4. Thereby, heat from the LED chip 2 is transmitted to the heat radiating member 5 through the base 1 of the substrate 1 and the bracket 4.

  The power supply unit 6 is for supplying power to the plurality of LED chips 2, and includes a substrate 61, a plurality of electronic components 62, a case 63, and two cables 64. The substrate 61 is made of, for example, glass epoxy resin, and in the present embodiment, has a long rectangular shape with the axial direction Na as the longitudinal direction. The plurality of electronic components 62 are for fulfilling the function of supplying power to the plurality of LED chips 2, and are mounted on both surfaces of the substrate 61 as shown in FIGS. 11 and 12. The plurality of electronic components 62 includes electronic components 62a to 62i. The electronic component 62a is a capacitor, the electronic component 62b is a diode, the electronic component 62c is a MOSFET element, the electronic component 62d is a capacitor, the electronic component 62e is a coil, and the electronic component 62f is a resistor. The electronic component 62g is an IC, the electronic component 62h is a diode, and the electronic component 62i is a bridge diode.

  The case 63 is made of, for example, a translucent resin and has a cylindrical portion 63a and a screw portion 63b. The cylindrical portion 63 a has a bottomed cylindrical shape whose axial direction is along the axial direction Na, and accommodates the substrate 61 and the plurality of electronic components 62. The screw part 63 b is formed below the cylindrical part 63 a in the axial direction Na, and has a male screw shape that is screwed into the base 7.

  The outer diameter of the cylindrical portion 63 a of the case 63 is slightly smaller than the inner diameter of the cylindrical portion 51 of the heat radiating member 5. Thereby, the cylindrical part 63 a of the case 63 and the part accommodated in the power supply part 6 are accommodated in the cylindrical part 51 of the heat radiating member 5.

  The two cables 64 have a core wire 64a and a coating 64b. One end of each core wire 64 a is attached to the substrate 61. As shown in FIGS. 4 and 6, the other end of each core wire 64 a is exposed to the main surface 1 c side of the substrate 1 through the through hole 43 of the bracket 4 and the through hole 11 of the substrate 1. The leading end portion of the core wire 64 a exposed from the substrate 1 is joined to the terminal pad 13 by solder 65. The upper end of the coating 64 b is located in the upper part of the through hole 43 in the drawing. The adhesive 44 is interposed between the substrate 1 and the pedestal portion 42 and fills the upper majority of the through hole 43 in the figure. Thereby, in the through-hole 43, the core wire 64a is not exposed.

  The base 7 is a part that is attached to a general lighting device for a light bulb that complies with JIS standards, for example. The base 7 is configured to satisfy the specifications such as E17 and E26 defined in the JIS standard. The base 7 is attached by being screwed to the threaded portion 63 b of the case 63 of the power supply unit 6.

  Next, an example of a manufacturing method of the LED bulb A will be described below.

  First, the long member 5A shown in FIG. 13 is formed. The long member 5A has a cylindrical portion 51A and a plurality of fins 52A, and a planar cross-sectional shape perpendicular to the axial direction Na is uniform in the axial direction Na. The cylindrical portion 51A has a cylindrical shape having a central axis extending in the axial direction Na, and the plurality of fins 52A are arranged radially about the central axis of the cylindrical portion 51A. Extrusion is used to form the long member 5A. The long member 5A having a uniform cross-sectional shape is continuously formed by pressing a billet made of, for example, aluminum at a high pressure against the die having the cross-sectional shape of the long member 5A.

  Next, the long member 5A is cut along the plurality of cut surfaces Cp shown in the drawing. The plurality of cut surfaces Cp are perpendicular to the axial direction Na and are arranged at equal intervals. Thus, the long member 5A is divided into a plurality of short members 5B shown in FIG.

  Next, the cylindrical portion 51B and the plurality of fins 52B of the short member 5B are cut along the cutting line Cl shown in FIG. This cutting is performed using a wire, for example. Cutting along the illustrated cutting line Cl is performed in all circumferential directions of the short member 5B. Thereby, the heat radiating member 5 shown in FIGS. 7-10 is obtained.

  Thereafter, as shown in FIG. 15, the power supply unit 6 is inserted into the heat radiating member 5. Further, the substrate 1 is attached to the pedestal portion 42 of the bracket 4. Then, the two cables 64 are joined to the substrate 1. Further, the globe 3 is attached to the heat radiating member 5 through the bracket 4. On the other hand, the base 7 is attached to the screw part 63 b of the power supply part 6. The LED bulb A shown in FIGS. 1 to 3 is obtained through the above steps.

  Next, the operation of the LED bulb A will be described.

  According to the present embodiment, the LED chip 2 is mounted on the substrate 1 made of ceramic. For this reason, it is easy to reduce the interval between the LED chips 2. Thereby, it is possible to increase the mounting density of the plurality of LED chips 2. Therefore, the brightness of the LED bulb A can be increased. Moreover, it becomes difficult to visually recognize that each of the plurality of LED chips 2 shines as a point light source by increasing the mounting density. Thereby, the LED bulb A can emit light more uniformly.

  The white resin layer 15 as a reflective layer suitably reflects light from the semiconductor layer 22 of the LED chip 2. Thereby, the light from the semiconductor layer 22 can be prevented from being absorbed by the submount substrate 21. Thereby, the high brightness of the LED bulb A can be further promoted. In particular, the white resin layer 15 covers all the side surfaces of the submount substrate 21. This is suitable for preventing light from the semiconductor layer 22 from being absorbed. The white resin layer 15 covers most of the wiring pattern 12. The wiring pattern 12 made of Ag is susceptible to corrosion called migration. The white resin layer 15 is suitable for preventing corrosion of the wiring pattern 12.

  The core wire 64 a of the cable 64 is surrounded by the solder 65, and is fixed to the substrate 1 by the solder 65. For this reason, an excessive bending moment is unlikely to act on the core wire 64a. Therefore, the cable 64 can be prevented from being detached from the substrate 1. Moreover, the part provided in the board | substrate 1 and the board | substrate 61 of the power supply part 6 among the cables 64 can be deform | transformed moderately. Therefore, even if the substrate 61 moves slightly with respect to the substrate 1, it is possible to prevent an excessive force from acting on the joint portion between the core wire 64 a and the substrate 1 due to an appropriate deformation of the cable 64. Unlike the present embodiment, when the core wire 64 a is joined to the wiring pattern 12 while being laid along the substrate 1, there is a high possibility that the wiring pattern 12 is peeled off by a moment acting on the cable 64. According to this embodiment, even if a moment acts on the cable 64, a force to peel off the wiring pattern 12 is unlikely to occur. Therefore, the wiring pattern 12 is excellent in protection.

  According to this embodiment, the heat radiating member 5 does not have a part where the axial Na viewed shape partially protrudes in the axial direction Na. Therefore, a plurality of heat radiating members 5 can be easily manufactured from the long member 5A formed by extrusion molding. Manufacturing using extrusion molding can reduce the manufacturing cost as compared with, for example, a die casting method. Therefore, the manufacturing cost of the LED bulb A can be reduced.

  When using die casting, the number of the plurality of fins 52 is limited because it is necessary to spread the casting material every corner. On the other hand, in this embodiment, since extrusion molding is used, there is almost no concern of insufficient material distribution. For this reason, it is possible to set a larger number of the plurality of fins 52, which is suitable for enhancing the heat dissipation effect of the heat dissipation member 5. Further, when the extrusion process is used, it is possible to increase the density of the heat dissipating member 5 as compared with the case where mold casting is used. This contributes to improving the thermal conductivity of the heat radiating member 5 and is advantageous for enhancing the heat radiating effect of the heat radiating member 5.

  By making the dimension in the radial direction Nd of the fin 52 closer to the LED chip 2 in the axial direction Na, it is possible to increase the surface area for heat dissipation at a portion that becomes higher temperature due to heat from the LED chip 2. it can. Thereby, the heat dissipation effect of the heat radiating member 5 can be increased reasonably.

  By attaching the substrate 1 to the pedestal 53, the heat from the LED chip 2 can be easily transmitted to the heat radiating member 5.

  By accommodating the power supply unit 6 in the cylindrical part 51, for example, a dedicated portion only for arranging the power supply unit 6 in the axial direction Na is not provided. This is preferable for reducing the size of the LED bulb A, particularly for reducing the axial Na dimension.

  Since the inner surface 31 of the globe 3 is a rough surface, the light from the LED chip 2 can be emitted from the outer surface 32 while being diffused. Thereby, each LED chip 2 becomes difficult to be visually recognized as a so-called point light source from the outside of the LED bulb A. Therefore, the LED bulb A can be visually recognized as a glowing light of the entire globe 3 in the same manner as a general incandescent bulb or more. If roughening is applied to the outer surface 32 in addition to the inner surface 31, a stronger diffusion effect can be expected.

  By forming the short member 5B and the heat dissipating member 5 from the long member 5A formed by extrusion of aluminum, the heat dissipating member 5 having a different axial Na dimension and the heat dissipating member 5 having a different shape in the radial direction Nd of the fin 52 are obtained. Even in the case of manufacturing, it can be easily handled by changing the setting of the cutting plane Cp and the cutting line Cl.

  FIGS. 16-26 has shown the modification from which the structure of each part of LED light bulb A differs. In these modified examples, the same elements as those described above are denoted by the same reference numerals and description thereof is omitted.

  The modification shown in FIG. 16 differs from the LED bulb A described above in the shape of the substrate 1 and the arrangement of the through holes 11, the terminal pads 13, and the core wires 64a. In this modification, the substrate 1 has a long rectangular shape as a whole. At the four corners of the substrate 1, chamfered portions 1a are formed. The region where the translucent resin 24 is formed is a light emitting region that emits light in a square shape. On the other hand, the region of the substrate 1 that is separated from the translucent resin 24 is a non-light emitting region 1b that does not emit light. The two through holes 11 are formed side by side in the non-light emitting region 1b.

  According to such a configuration, by providing the chamfered portion 1a, it is possible to prevent the substrate 1 from becoming unduly large while enlarging the translucent resin 24 as the light emitting region.

  The modification shown in FIGS. 17 and 18 includes a clip 17 and a heat transfer layer 16. The heat transfer layer 16 is made of a resin having a relatively high thermal conductivity. The heat transfer layer 16 is disposed so as to surround the light-transmitting resin 24, and each overlaps the wiring pattern 12. The clip 17 is fixed to the bracket 4 with a bolt 18 at one end. The other end of the clip 17 is bent and presses the substrate 1 through the heat transfer layer 16.

  According to such a configuration, the substrate 1 can be more firmly fixed by the clip 17. Further, heat from the LED chip 2 can be transferred to the bracket 4 via the wiring pattern 12, the heat transfer layer 16, and the clip 17. The heat transmitted to the bracket 4 is preferably transmitted to the heat radiating member 5 and radiated.

  FIG. 19 shows an example in which the heat transfer layer 16 is formed of a metal such as Ag. In this case, the heat transfer layer 16 is slightly separated from the wiring pattern 12. Even with such a configuration, the heat from the wiring pattern 12 is transmitted to the heat transfer layer 16, and the heat from the LED chip 2 can be appropriately dissipated.

  FIG. 20 shows a modification in which the arrangement of the translucent resin 24 is different. In the present modification, the translucent resin 24 is provided in such a posture that its four sides are inclined with respect to the four sides of the substrate 1. The heat transfer layer 16 is formed around the four corners of the substrate 1. Also in such a modification, it is possible to increase the brightness of the LED bulb A and make the light emission uniform, and it is possible to promote the heat dissipation of the LED chip 2.

  FIG. 21 to FIG. 26 show a modification including the reflector 25. In the modification shown in FIGS. 21 and 22, the reflector 25 has a substantially square shape and is attached to the substrate 1. The reflector 25 is made of, for example, white resin and has a plurality of openings 26 formed therein. The plurality of openings 26 are arranged in a 4 × 4 matrix. Each opening 26 has a substantially square shape. Each opening 26 surrounds four LED chips 2. As shown in FIG. 22, the inner surface of the opening 26 is inclined such that the distance between the facing surfaces increases in the normal direction of the main surface 1 c of the substrate 1 as the distance from the substrate 1 increases.

  According to such a configuration, the light from the LED chip 2 is reflected by the reflector 25, whereby the increase in the brightness of the LED bulb A can be further promoted. By accommodating the plurality of LED chips 2 in the openings 26, it is possible to avoid the portions between the adjacent openings 26 of the reflector 25 from hindering the high-density mounting of the LED chips 2.

  In the modification shown in FIG. 23, each opening 26 has a hexagonal shape, and the reflector 25 has a structure called a honeycomb structure. One LED chip 2 is accommodated in each opening 26. According to such a configuration, the distance from the LED chip 2 to the inner surface of the opening 26 can be made uniform. This is preferable for increasing the brightness of the LED bulb A and making the light emission uniform. Moreover, it contributes to high density mounting of the plurality of LED chips 2.

  In the modification shown in FIG. 24, each opening 26 has a square shape. The opening 26 in the center accommodates one LED. The eight openings 26 surrounding the central opening 26 are relatively small, and each accommodates one LED chip 2. Further, the twelve openings 26 arranged on the outermost side are relatively large, and each accommodates four LED chips 2. The mounting density of the plurality of LED chips 2 becomes denser from the center of the substrate 1 toward the periphery.

  According to such a configuration, the density of the LED chip 2 that is a heat generation source is small in the portion near the center of the substrate 1, and the heat generation is relatively small. On the other hand, the portion near the periphery of the substrate 1 has a high density of the LED chips 2 and a relatively large amount of heat generation. From this peripheral portion, heat is easily released through the clip 17. Therefore, any portion of the substrate 1 can be prevented from becoming locally hot.

  In the modification shown in FIG. 25, the reflector 25 has a honeycomb structure. One LED chip 2 is accommodated in the central opening 26. Two LED chips 2 are accommodated in the six openings 26 surrounding the central opening 26. Three LED chips 2 are accommodated in the twelve openings 26 arranged on the outermost side. Even with such a configuration, any portion of the substrate 1 can be prevented from becoming locally hot.

  In the modification shown in FIG. 26, the plurality of openings 26 are concentric circular or annular. The central opening 26 is circular and accommodates one LED chip 2. The opening 26 surrounding the central opening 26 is annular and accommodates twelve LED chips 2. The opening 26 arranged on the outermost side has an annular shape and accommodates a plurality of LED chips 2 arranged at a higher density than the opening 26 adjacent to the central opening 26. Even with such a configuration, any portion of the substrate 1 can be prevented from becoming locally hot.

  The LED bulb according to the present invention is not limited to the above-described embodiment. The specific configuration of each part of the LED bulb according to the present invention can be varied in design in various ways.

A LED bulb Cp Cutting plane Cl Cutting line Na Axial direction Nd Radial direction 1 Substrate 1a Chamfer 1b Non-light emitting area 1c Main surface 10 Glass layer 11 Through hole 12 Wiring pattern 13 Terminal pad 14 Through hole metal layer 15 White resin layer (reflection) layer)
16 Heat transfer layer 17 Clip 18 Bolt 2 LED chip 21 Submount substrate 22 Semiconductor layer 23 Wire 24 Translucent resin 25 Reflector 26 Opening 3 Globe 31 Inner surface 32 Outer surface 4 Bracket 41 Edge portion 42 Base portion 43 Through-hole 44 Adhesive 5 Heat dissipation Member 51 Tubular portion 52 Fin 53 Base portion 5A Long member 51A Tubular portion 52A Fin 5B Short member 51B Tubular portion 52B Fin 6 Power supply portion 61 Substrate 62 Electronic component 63 Case 63a Tubular portion 63b Screw portion 63c Projection 64 Cable 64a Core wire 64b Coating 65 Solder 7 Cap

Claims (32)

A substrate having a main surface and made of ceramic;
A plurality of LED chips mounted on the main surface of the substrate;
A heat dissipating member that supports the substrate and that transmits heat from the LED chip through the substrate;
A globe that covers the plurality of LED chips and transmits light from the plurality of LED chips;
A base attached to the side opposite to the globe with respect to the heat dissipation member;
LED bulb characterized by comprising. A wiring pattern that is electrically connected to the plurality of LED chips is formed on the substrate,
The LED bulb according to claim 1, further comprising a reflective layer covering at least a part of the wiring pattern.   The LED bulb according to claim 2, wherein the reflective layer is white. The LED chip has a submount substrate made of Si, and a semiconductor layer mounted on the submount substrate, and the main surface of the substrate is positioned so that the submount substrate is located on the substrate side. Implemented,
The reflective layer is made of a material that covers at least a part of the side surface of the submount substrate facing a direction perpendicular to the normal direction of the main surface and has a higher reflectance than the submount substrate. Item 4. The LED bulb according to Item 2 or 3.   The LED bulb according to claim 4, wherein the reflective layer covers all of the side surfaces of the submount substrate.   The LED bulb according to claim 4, wherein the reflective layer exposes all of the semiconductor layer.   The LED bulb according to claim 4, wherein a Zener diode for avoiding an excessive reverse voltage applied to the semiconductor layer is formed on the submount substrate.   The LED bulb according to any one of claims 1 to 7, further comprising a translucent resin that covers the plurality of LED chips and transmits light from the plurality of LED chips.   The said translucent resin contains the fluorescent material which emits the light from which a wavelength differs from the light from these LED chips by being excited by the light from these LED chips. LED bulb.   The LED bulb according to any one of claims 1 to 9, comprising a reflector attached to the substrate and having a plurality of openings each having an inner surface surrounding one or more LED chips.   The LED bulb according to claim 10, wherein the inner surface is inclined so as to be separated from the LED chip in an in-plane direction of the main surface as it is away from the main surface in a normal direction of the main surface.   The LED light bulb according to claim 10 or 11, wherein the plurality of openings include one that accommodates the plurality of LED chips.   The LED bulb according to claim 10 or 11, wherein all the plurality of openings accommodate a plurality of the LED chips.   The LED bulb according to any one of claims 10 to 13, wherein the plurality of openings have a rectangular shape when viewed in the normal direction of the main surface.   The LED bulb according to any one of claims 10 to 13, wherein the plurality of openings have a hexagonal shape when viewed in the normal direction of the main surface.   The LED bulb according to any one of claims 10 to 13, wherein the plurality of openings are concentric rings in a normal direction view of the main surface.   The LED bulb according to any one of claims 1 to 16, wherein the mounting density of the plurality of LED chips becomes denser from the center of the substrate toward the periphery. The heat dissipating member has a cylindrical portion whose axial direction is the normal direction of the main surface,
A power supply unit that is housed in the cylindrical part and supplies power to the plurality of LED chips;
Two through holes are formed in the substrate,
The LED light bulb according to any one of claims 1 to 17, wherein the power supply unit includes two cables having a core wire inserted through the through hole from a side opposite to the main surface. On the substrate, a wiring pattern including two terminal pads surrounding each of the through holes is formed.
The LED light bulb according to claim 18, wherein a portion of the core wire that protrudes from the substrate toward the main surface is bonded to the terminal pad by solder. Comprising a translucent resin covering the plurality of LED chips,
The LED light bulb according to claim 18 or 19, wherein the two through holes are arranged with the translucent resin interposed therebetween. The substrate has a long rectangular shape, and has a light emitting region in which the translucent resin is formed and a non-light emitting region adjacent to the light emitting region.
The LED light bulb according to claim 20, wherein the two through holes are arranged in the non-light emitting region.   The LED bulb according to claim 21, wherein chamfered portions are formed at four corners of the substrate. The light emitting area is rectangular,
The LED bulb according to claim 22, wherein the four sides of the light emitting region and the four sides of the substrate are inclined with respect to each other.   24. The LED bulb according to claim 1, further comprising a clip that fixes the substrate by applying an elastic force that presses the substrate in a direction opposite to a normal direction of the main surface.   The LED light bulb according to claim 24, wherein a heat transfer layer in contact with the clip is formed on the main surface of the substrate.   26. The LED bulb according to claim 25, wherein the heat transfer layer is made of metal and is separated from the wiring pattern.   26. The LED bulb according to claim 25, wherein the heat transfer layer is made of a highly thermally conductive resin and is in contact with the wiring pattern.   The heat dissipating member includes a cylindrical portion having a uniform cross-sectional shape in a plane perpendicular to the axial direction that coincides with the normal direction of the main surface, and each extending outward from the cylindrical portion. The LED bulb according to any one of claims 1 to 27, comprising a plurality of fins extending in the axial direction and having a constant plate thickness at portions where the positions in the axial direction are the same.   29. The LED bulb according to claim 28, wherein the cylindrical portion has a cylindrical shape.   30. The LED bulb according to claim 28 or 29, wherein the plurality of fins are arranged radially about a central axis of the cylindrical portion.   The LED bulb according to claim 30, wherein a dimension of each fin in the radial direction with respect to the axial direction is larger as it is closer to the LED chip.   32. The LED bulb according to claim 1, wherein the heat dissipating member is made of aluminum.

Images