JPWO2009044716A1 - Light emitting device - Google Patents

Abstract

It is possible to smoothly and efficiently dissipate the heat generated by the light emitting element, to extend the life of the light emitting element, and to prevent uneven brightness of the light emitting element. Provided is a light-emitting device having excellent conductivity, heat dissipation, radiation, and the like. The light emitting device includes a radiator that holds a plurality of light emitting elements and a cover body, and a base that supplies power to the plurality of light emitting elements. The radiator has a heat radiation hole penetrating in the optical axis direction of the light emitting element and a heat radiation fin formed on the outer periphery facing the external space of the heat radiator. Heat generated from the plurality of light emitting elements is dissipated by natural convection of air flowing through the heat radiation holes and the heat radiation fins.

Description

    The present invention relates to a light emitting device using, for example, an LED element, and more particularly to a light emitting device that is improved in thermal conductivity, heat dissipation, radiation, and the like.

Conventionally, for example, since the luminous efficiency of light emitting diodes (LED elements) has been increased, various LED elements having a large energy saving effect are mounted on a wiring board in high density instead of incandescent lamps for illumination. A light emitting device (illumination device) has been proposed. As an example of this conventional light emitting device, for example, there is one that is smaller than an existing incandescent bulb and provided with a base for connection to an existing electric light socket (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2001-243809

    However, although the luminous efficiency of this type of LED element exceeds about 5 times that of existing incandescent bulbs, the luminous efficiency with respect to the input power is still low, and most of the input power is changed to heat. For this reason, in a light emitting device in which a plurality of LED elements are mounted on a wiring board at a high density, the total amount of heat generated by the LED elements increases, resulting in a decrease in light emission efficiency of the LED elements and a shortened life of the LED elements. There was a problem of doing. Further, there is a problem that luminance unevenness occurs due to a decrease in luminous efficiency of the LED element.

  Accordingly, the present invention has been made in order to solve the above-described conventional problems, and a specific object thereof is to smoothly and efficiently dissipate heat generated from the light emitting element, and to improve the efficiency of the light emitting element. An object of the present invention is to provide a light-emitting device that can extend the life and can prevent unevenness in luminance of the light-emitting element and is excellent in thermal conductivity, heat dissipation, radiation, and the like.

   [1] In order to achieve the above object, the present invention provides a light emitting unit having a plurality of light emitting elements, a first surface holding the light emitting unit, and a second surface formed on the opposite side of the first surface. The heat radiator has a first heat radiating portion that radiates heat generated by the light emitting portion to the outer periphery, and the heat and the first surface and the second surface. And a second heat dissipating part that diffuses to the inner periphery of the hole formed between the two.

   [2] In the invention described in [1] above, the radiator has a radiating fin on an outer periphery.

  [3] In the invention described in [1], the hole is formed on a central axis of the first surface and the second surface.

  [4] In the invention described in [1], a plurality of the holes are formed on concentric circles centering on a central axis of the first surface and the second surface.

  [5] In the invention described in [1] above, the light emitting unit includes a wiring board on which the plurality of light emitting elements are mounted, and a translucent cover that covers the plurality of light emitting elements and the wiring board. The light emitting device further includes a housing that holds the second surface of the radiator, a circuit board that drives and controls the plurality of light emitting elements, and the heat dissipation of the housing. And a base for supplying electric power to the plurality of light emitting elements.

   [6] In the invention described in [1], a cylindrical lens having a focal point on a line connecting the centers of the plurality of light emitting elements is provided.

  [7] In the invention described in [5] above, the housing includes a space portion communicating with the hole of the radiator and a plurality of communication holes communicating with the space portion. Each of the communication holes is characterized by opening to the external space.

  [8] In the invention described in [5], a lead wire for electrically connecting the wiring board and the circuit board is arranged through the hole.

  [9] In the invention described in [5], the wiring board is attached to the radiator through an insulating sheet having thermal conductivity.

  [10] In the invention described in [5], the circuit board is provided in the base.

  [11] In the invention described in [1] above, the radiator includes a first tubular member, and a second tubular member disposed coaxially with respect to the first tubular member. The hole is formed between the first tubular member and the second tubular member.

  [12] In the invention described in [11] above, the hole is divided into a plurality of portions by a partition extending from one end to the other end.

  [13] In the invention described in [11] above, a power supply board that drives and controls the plurality of light emitting elements is disposed inside the first cylindrical member.

  [14] In the invention described in [11] above, a wiring board on which the plurality of light emitting elements are mounted is provided at one end of the first cylindrical member, and the wiring board includes the wiring board. The heat detection element which detects the temperature of this or the ambient temperature is provided.

  [15] The invention described in [14] above, wherein the plurality of light emitting elements are driven and controlled based on a change in detection output from the heat detection element.

  The present invention can smoothly, easily and efficiently dissipate heat generated from a light-emitting element, so that the lifetime of the light-emitting element can be extended and high luminance of the light-emitting device can be sufficiently secured. It becomes possible. In addition, a light-emitting device that is excellent in insulation, thermal conductivity, heat dissipation, radiation, and the like can be obtained.

FIG. 1A is a perspective view showing an overall configuration of a light emitting device according to a first embodiment of the present invention. FIG. 1B is a longitudinal sectional perspective view showing the internal structure of the light emitting device according to the first embodiment. 2 is a cross-sectional view taken along line II-II in FIG. 1A. FIG. 3A is a front view of a radiator that is one component of the light-emitting device according to the first embodiment. FIG. 3B is a top view of the radiator. 3C is a cross-sectional view taken along line III-III in FIG. 3B. FIG. 4 is a circuit diagram schematically showing a drive circuit of the light emitting device according to the first embodiment. FIG. 5A is a cross-sectional view of a radiator that is a first modification. FIG. 5B is a cross-sectional view of a radiator that is a second modification. FIG. 6 is a longitudinal sectional perspective view showing the internal structure of the light emitting device according to the second embodiment. It is a longitudinal cross-sectional view which shows the internal structure of the light-emitting device which concerns on 2nd Embodiment. It is a disassembled perspective view of the light-emitting device which concerns on 2nd Embodiment. It is a circuit diagram which shows roughly the drive circuit of the light-emitting device which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 LED chip 3 LED board 4 Insulating sheet 5 Light-emitting part 10 Cover body 11 Bulging part 12 Mounting plate part 13 Reflector 13a Reflecting surface 16 Reflecting mirror 20, 40 Radiator 20a Inner cylinder 20b Outer cylinder 20c Partition plate 21, 42c Holes 21a and 21b Opening 22 Inner wall 22a Mounting part 23 Outer wall 24 Radiating fin 25 Concave groove part 30 Housing 31 Inner case 32 Outer case 32a Large diameter base part 32b Small diameter part 32c Tip part 32d Taper step part 32e Opening hole 33 Mounting seat Portion 34 Heat radiation space 35 Power supply board 36a, 36b, 37a, 37b Lead wire 38 Base 39 Screw groove 41 Holding case 41a Main body holding portion 41b Tubular mounting portion 42 Heat radiation case 42a Inner tube portion 42b Outer tube portion 42d Partition wall 43 First Radiation ring 43a, 45a Outer frame 43b, 45b Inner frame 43c, 45c Connection Bed 43d, 45d opening 44 base case 44a cylinder 44b mounting boss 45 second radiating rings 50 drive circuit 51 commercial power supply 52 diode bridge 53 a smoothing capacitor 54 control unit 55 coil 56 switching element 57 regenerative diode 58 Thermistor

    Preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings.

(First embodiment)
FIG. 1A is a perspective view showing the overall configuration of the light emitting device according to the first embodiment, and FIG. 1B is a longitudinal sectional perspective view showing the internal structure of the light emitting device. 2 is a cross-sectional view taken along line II-II in FIG. 1A. 3A is a front view of a radiator that is one component of the light emitting device, FIG. 3B is a top view of the radiator, and FIG. 3C is a cross-sectional view taken along line III-III in FIG. 3B.

(External structure of light emitting device)
In FIG. 1A, FIG. 1B, and FIG. 2, the code | symbol 1 has shown the whole structure of the light-emitting device based on this 1st Embodiment. The basic configuration of the light-emitting device 1 includes a translucent cover body 10 that covers the plurality of light-emitting elements (LED chips) 2,... 4 having a cylindrical radiator 20 that radiates heat to the space, a casing 30 that holds the radiator 20, and a base 38 that is provided on a part of the casing 30 opposite to the part that holds the radiator 20. It is mainly composed of two components. The cover body 10, the radiator 20, the housing 30, and the base 38 are assembled on the same straight line.

(Configuration of light emitting part)
According to the illustrated example, the 30 LED chips 2 are components (SMD) that can be surface-mounted on a thermally conductive wiring board (LED board) 3 having a circuit pattern, and are mounted in an annular shape. The LED substrate 3 has an annular shape, and is thermally connected to a flat mounting surface (first surface) of the radiator 20 via a thermally conductive insulating sheet 4 that also has an annular shape. Yes. A light emitting part is constituted by the LED chip 2, the LED substrate 3, and the insulating sheet 4.

  The arrangement form, arrangement pitch, arrangement number, and the like of the LED chips 2 are not limited to the illustrated example. As an arrangement form of the LED chips 2, for example, two or more LED chips 2 are linearly or curved so that the light loss of the LED chip 2 that is a point light source is reduced and a light condensing / diffusing action is obtained. It is preferable to arrange in a line. The LED chip 2 may be arranged in, for example, a polygonal shape, a cross shape, or an H shape. The first embodiment uses, for example, a single-row LED chip 2, but is not limited to the illustrated example. For example, instead of the single-row LED chip 2, the LED chip 2 is arranged in a circular shape. Alternatively, the LED chips 2 may be arranged in a double row on a concentric circle. On the LED substrate 3, for example, the LED chip 2 in a bare chip state may be mounted.

  What is necessary is just to set suitably, for example according to the light quantity of the LED chip 2, a brightness | luminance, etc. as the arrangement | sequence pitch and arrangement | positioning number of the LED chip 2. It is not limited to the LED chip 2 of the example of illustration, For example, the LED chip sealed with resin containing a fluorescent substance may be mounted. The phosphor may be applied directly to the bare LED, applied to the cap, or applied to the cover body 10. Instead of the LED chip 2, another light source such as an EL element can be used.

  The circuit pattern of the LED substrate 3 is electrically connected in series with the LED chip 2. As the LED substrate 3, for example, a glass epoxy resin substrate or an aluminum substrate can be used. As a material of the insulating sheet 4, for example, silicon rubber is used, but a material having a high thermal conductivity such as ceramic mixed in silicon rubber may be used. In place of the insulating sheet 4, grease or adhesive having high thermal conductivity can be used, but it is not necessary to use it.

(Structure of the cover body)
As shown in FIGS. 1A, 1B, and 2, the cover body 10 that guides light from the LED chip 2 to the external space is formed in an annular shape from a transparent acrylic resin material. As a material of the cover body 10, for example, a light-transmitting material such as silicon resin or glass can be used. The cover body 10 includes an annular bulging portion 11 that bulges outward in a hemispherical concave cross-section, and a pair of mounting plate portions 12 and 12 that project radially from the inner peripheral edge of the bulging portion 11. And have. The bulging portion 11 of the cover body 10 is disposed on the mounting surface (first surface) of the radiator 20 so as to cover the plurality of LED chips 2 formed in an annular shape. The cover 10 is held and fixed to the radiator 20 by screwing the attachment plate portion 12 to the attachment surface of the radiator 20 via the LED substrate 3 and the insulating sheet 4.

  The structure of the cover body 10 is not limited to the illustrated example. For example, a reflective sheet is attached to the outer peripheral surface of the lower end of the cover body 10 or an area other than the wiring pattern of the LED board 3 or a reflective layer is deposited. Or you may. As another structure of the cover body 10, for example, a cylindrical lens that concentrates and diffuses the light from the LED chip 2 may be provided on the cover body 10, or may be configured by a cylindrical lens, or a combination of these structures. It may be. The outer shape of the cover body 10 is not limited to the illustrated example. Another external shape of the cover body 10 may be a shell body having a polygonal cross-sectional shape such as a triangle, a quadrangle, or a pentagon.

(Configuration of radiator)
As shown in FIGS. 2 and 3A to 3C, the radiator 20 that dissipates heat generated during lighting of the plurality of LED chips 2 is a cylinder having both ends of the first surface and the second surface. Consists of the body. The material of the radiator 20 is made of a material having excellent thermal conductivity such as an aluminum material or a ceramic material.

  This heat radiator 20 has LED chips on a hole (heat radiating flow path portion) 21 formed through the inside of the cylindrical body along the central axis and an outer wall (first heat radiating portion) 23 facing the external space. The plurality of radiating fins 24,... 24 are provided in a concavo-convex shape extending in the direction of the two optical axes. A part of the inner wall (second heat radiating portion) 22 forming the space of the heat radiating flow path portion 21 is provided with a pair of mounting portions 22a, 22a that are attached to the cover body 10 and the housing 30 so as to protrude inward. Yes. The heat radiator 20 is produced by integrally forming the heat radiating flow path portion 21, the attachment portion 22a, and the heat radiating fins 24 by extrusion molding.

  In the illustrated example, the number of the radiation fins 24 is set to be equal to the number of LED chips 2 installed. The installation position of the radiation fin 24 is provided at a position corresponding to the LED chip 2. With this configuration, air passes through the concave groove portion 25 formed between adjacent radiating fins 24 while being rectified, so that natural convection of the air is likely to occur, and heat generated by the LED chip 2 is easily dissipated.

  The heat radiator 20 configured as described above dissipates heat generated from the LED chip 2 by natural convection of air flowing through the heat radiation channel portion 21 and the plurality of heat radiation fins 24. In addition, the heat generated from the LED chip 2 is radiated as radiant heat by the cylindrical body of the radiator 20. Due to these synergistic effects, the efficiency of heat exchange by the radiator 20 can be improved, and the heat generated in the LED chip 2 can be dissipated smoothly, easily and efficiently.

  In the first embodiment, heat generated from the LED chip 2 by natural convection of air flowing through the single heat radiation channel portion 21 of the heat radiator 20 and the plurality of square columnar heat radiation fins 24. However, the present invention is not limited to the illustrated example. Other examples of the radiator 20 include, for example, the shape, surface area, arrangement form, and number of installed heat radiation channels 21 and the radiation fins 24 of the radiator 20 based on the light quantity, luminance, and the number of installed LED chips 2. Of course, can be set appropriately. The shape of the radiator 20 is not limited to a cylindrical body, and may of course be a cylinder having a polygonal cross-sectional shape such as a triangle, a quadrangle, or a pentagon.

(Structure of radiator housing)
As shown in FIGS. 1A, 1 </ b> B, and 2, the housing 30 that holds the radiator 20 has an inner / outer double structure including an inner case 31 and an outer case 32. The material of the housing 30 is made of an insulating resin material such as polycarbonate. The inner case 31 and the outer case 32 are fixed by screw tightening. The inner case 31 has a cylindrical shape, and a pair of columnar mounting seats 33 and 33 having a circular recess that opens to the opposite side of the radiator 20 project from the wall on the radiator side. Has been. The radiator 20 is held and fixed to the housing 30 by screwing the other end surface (second surface) of the radiator 20 opposite to the cover body 10 through the mounting seat portion 33.

  The outer case 32 of the housing 30 includes a large-diameter base portion 32a having a storage space for accommodating the inner case 31, a small-diameter portion 32b having a smaller diameter than the large-diameter base portion 32a, and a tip portion 32c having a smaller diameter than the small-diameter portion 32b. And have. The outer case 32 is configured as a multi-stage cylindrical case body in which a large-diameter base portion 32a, a small-diameter portion 32b, and a distal end portion 32c are connected by a tapered step portion 32d whose diameter is reduced toward the base 38 side. The large diameter base portion 32 a of the outer case 32 has substantially the same dimensions as the outer diameter of the radiator 20. A base 38 used for a general light bulb is fixed to the distal end portion 32 c of the outer case 32. The base 38 is made of a metal material such as iron or brass. A screw groove 39 having a spiral shape is formed on the outer periphery of the base 38.

  The inner case 31 and the outer case 32 of the housing 30 and the radiator 20 form a heat radiation space 34 serving as a path for the outside air. A plurality of arch-shaped openings (communication holes) 32e,... 32e are formed in the outer peripheral portion of the large-diameter base 32a of the outer case 32 with a predetermined phase difference. As shown in FIG. 2, the opening 32 e coincides with the peripheral surface of the heat radiating space 34, communicates with the opening 21 a of the heat radiating channel 21 in the radiator 20, and opens to the external space of the light emitting device 1. is doing.

(Configuration of light emitting device drive circuit)
As shown in FIGS. 1A, 1B, and 2, a circuit board (power supply board) 35 that constitutes a drive circuit that drives and controls the LED chip 2 is housed in the inner case 31 of the housing 30. The power supply substrate 35 is disposed in the vicinity of the base 38, but is not limited to the illustrated example. For example, the power supply substrate 35 may be provided inside the base 38. Lead wires 36 a and 36 b that electrically connect the LED substrate 3 and the power supply substrate 35 are arranged via the heat dissipation flow path portion 21 of the radiator 20. The power supply substrate 35 is electrically connected to the base 38 via lead wires 37a and 37b. The power supply board 35 is illustrated with various electronic components to be mounted omitted.

  FIG. 4 is a circuit diagram schematically showing a drive circuit of the light emitting device. In the figure, the power supply substrate 35 has a drive circuit 50 that converts an alternating voltage input via lead wires 37a and 37b into a constant current of DC 50 mA, for example. The drive circuit 50 rectifies the AC voltage input from the commercial power supply 51 of AC 100V via the lead wires 37a and 37b into a DC voltage by the diode bridge 52, smoothes it by the smoothing capacitor 53, and then sends it to the control unit 54 by 50 mA. The DC voltage dropped to a constant current is output. The coil 55, the LED chip 2, and the switching element 56 are connected in series to this DC voltage. Between the cathode side of the LED chip 2 and the power supply side of the coil 55, a regenerative diode 57 for supplying a regenerative current is connected.

  The control unit 54 includes an IC chip (not shown), a current detection circuit, and the like, and performs an operation of repeatedly turning on and off the switching element 56. When the switching element 56 is turned on, a current flows through a circuit including the coil 55, the LED chip 2, and the switching element 56. When the switching element 56 is turned off, a current that continues to flow through the coil 55 flows as a regenerative current in a loop formed in the LED chip 2 and the regenerative diode 57. The current flowing through the switching element 56 is fed back to the current detection circuit, and the switching element 56 is controlled. Of course, the configuration of the drive circuit 50 is not limited to the illustrated example.

(Configuration of heat dissipation path)
As described above, the basic configuration of the heat dissipation path of the light emitting device 1 according to the first embodiment can be divided into the following two configurations.
(1) A heat dissipation path by heat conduction from the LED chip 2 to the radiator 20.
(2) A heat dissipation path by natural convection of air flowing from the radiator 20 to the external space and a heat dissipation path by radiation of the radiator 20.

  As described above, the heat dissipation path from the LED chip 2 to the radiator 20 by heat conduction is preferably transmitted to the radiator 20 via the LED board 3 and the insulating sheet 4 having thermal conductivity. . In addition to the above-described configuration, for example, by increasing the surface area of the radiator 20, the heat dissipation path by natural convection of air flowing from the radiator 20 to the external space and the heat dissipation path by radiation of the radiator 20 It is preferable to increase the contact area. In addition, it is preferable to reduce the thermal resistance between the radiator 20 and the light emitting unit by subjecting the mounting portion 22a of the radiator 20 to surface processing such as polishing.

(Heat dissipation of light emitting device)
Next, an example of the heat radiation action of the light emitting device 1 according to the first embodiment will be described with reference to FIG.

  Now, when the base 38 of the light emitting device 1 configured as described above is electrically connected to a commercial power supply by mounting it on a general incandescent light bulb socket, an AC voltage of 100 volts supplied to the base 38 is It is converted into a DC voltage of 3 volts by the power supply circuit of the power supply substrate 35 through the lead wire 37. This DC voltage is applied to each of the 30 LED chips 2 arranged on the LED substrate 3 from the electronic component on the power supply substrate 35 via the lead wire 36, and each of the LED chips 2 emits light. Light from the LED chip 2 enters the cover body 10. The light incident on the cover body 10 is emitted toward the outside of the light emitting device 1 and illuminates the peripheral portion brightly.

  During the lighting of the LED chip 2, heat is generated by the electric power that has not been converted into light. This heat reaches the radiator 20 via the LED substrate 3 and the insulating sheet 4. The heat diffuses in the heat radiator 20 and diffuses to the heat radiation channel portion 21 and the plurality of heat radiation fins 24 of the heat radiator 20. The heat transmitted to the tips of the plurality of radiating fins 24 is dissipated into the air by heat exchange with the outside air along the concave groove portions 25 that form air flow paths formed between the adjacent radiating fins 24.

  On the other hand, the air present in the heat radiation channel portion 21 of the radiator 20 is warmed by the heat conducted to the inner wall 22 of the heat radiation channel portion 21 and passes through the opening 21a on the housing 30 side of the heat radiation channel portion 21. Thus, an air flow toward a plurality of openings 32e orthogonal to the heat radiation space 34 of the housing 30 is generated. This air is discharged to the external space of the light emitting device 1 through each of the openings 32 e of the housing 30. New air from the external space flows into the heat radiation space 34 of the housing 30 through the heat radiation channel 21 and the opening 21a from the opening 21b opposite to the opening 21a of the heat radiation channel 21. The air is discharged to the external space of the light emitting device 1 through each of the openings 32e of the housing 30.

  Thereby, combined with the synergistic action of the natural convection of the air flowing through the plurality of radiating fins 24 and the radiant heat from the cylindrical body of the radiator 20, it is possible to more efficiently obtain the heat radiation effect by the natural convection of the air. . The heat generated during lighting of the LED chip 2 can be efficiently dissipated to the external space of the light emitting device 1, and the temperature during lighting of the LED chip 2 can be stabilized.

(Effects of the first embodiment)
According to the first embodiment, the following various effects can be obtained.
(1) The heat generated by the LED chip 2 can be radiated smoothly, reliably and efficiently.
(2) The high brightness of the LED chip 2 can be sufficiently secured.
(3) It is possible to increase the light emission efficiency by suppressing the heat generation of the LED chip 2.
(4) The lifetime of the LED chip 2 can be extended.
(5) A light emitting device excellent in insulation, thermal conductivity, heat dissipation, radiation and the like can be obtained.

(Modification of radiator)
FIG. 5A shows a modification of the radiator, and FIG. 5B shows another modification of the radiator. 5A and 5B are cross-sectional views of the radiator. In these drawings, substantially the same members as those in the first embodiment are given the same member names and symbols. Therefore, the detailed description regarding these members is omitted.

  As shown in FIG. 5A, the radiator 20 has an inner / outer double structure formed of an inner cylinder 20a and an outer cylinder 20b. The inner cylinder 20a and the outer cylinder 20b are connected and fixed by a partition plate (partition wall) 20c formed over the axial direction of the cylindrical body, and are partitioned into three heat radiation flow path portions 21. A plurality of heat radiation fins erected in an uneven shape extending in the optical axis direction of the LED chip 2 may be provided on the inner wall 22 of the inner cylinder 20a. As another modification of the radiator 20, as shown in FIG. 5B, a plurality of heat radiation flow path portions 21 can be formed on concentric circles centering on the central axis of the cylindrical body. The heat radiating fins 24 may be excluded from the outer surface wall 23 of the radiator 20.

  The radiator 20 according to these modified examples can be integrally formed by extrusion molding as in the first embodiment. Even in these modified examples, in addition to the same effects as those of the first embodiment, the heat generated during the lighting of the LED chip 2 can be more efficiently transmitted to the external space of the light emitting device 1. It becomes possible to dissipate.

(Second Embodiment)
Next, a preferred second embodiment of the present invention will be specifically described with reference to the accompanying drawings. 6 is a longitudinal sectional perspective view showing the internal structure of a light emitting device according to a second embodiment of the present invention, and FIG. 7 is a longitudinal sectional view showing the internal structure of the light emitting device. 8 is an exploded perspective view of the light emitting device. In these drawings, detailed description of substantially the same members as those in the first embodiment is omitted.

(External structure of light emitting device)
6-8, the code | symbol 1 has shown schematically the whole structure of the typical light-emitting device based on this 2nd Embodiment. In these drawings, the first embodiment is greatly different from the first embodiment in the first embodiment, a single cylindrical body (cylindrical member) having both ends of the first surface and the second surface. In the second embodiment, the hole formed between the first cylindrical member and the second cylindrical member is formed by penetrating the hole on the central axis of the first cylindrical member. It is in the point which penetrated.

  As shown in FIGS. 6 to 8, the basic configuration of the light emitting device 1 includes a light emitting unit 5 having a plurality of light emitting elements (LED chips) 2 and heat generated by the plurality of LED chips 2. It is mainly composed of three components that unitize an inner / outer double cylindrical radiator 40 that radiates heat and a base 38 that supplies power to the plurality of LED chips 2. The light emitting unit 5, the radiator 40, and the base 38 are assembled on the same straight line.

(Configuration of light emitting part)
As shown in FIGS. 6 and 7, the plurality of LED chips 2 are components (SMD) that can be surface-mounted on an annular LED substrate 3 having a circuit pattern and having thermal conductivity, and are annularly formed on the LED substrate 3. Has been implemented. On the LED substrate 3, an annular reflector 13 that reflects light from the plurality of LED chips 2 and radiates the light to the outside is disposed on the inner peripheral side of the LED chip 2. The LED board 3 is thermally connected to the radiator 40 via the annular insulating sheet 4 having thermal conductivity, and is covered with a flat cap-like cover body 10 having translucency. The light emitting unit 5 is mainly configured by unitizing the LED substrate 3 on which the LED chip 2 is mounted, the reflector 13, the insulating sheet 4, and the cover body 10.

  The reflector 13 is not particularly limited, but is attached to the LED board 3 by screwing. As shown in FIGS. 6 to 8, the reflector 13 has a reflecting surface 13 a that spreads toward the LED substrate 3. Half of the reflective surface 13a in the circumferential direction is formed by cutting out the lead wires 36a and 36b for electrically connecting the LED substrate 3 and the base 38. As a material of the reflector 13, for example, a synthetic resin material such as ABS resin can be used.

  The cover body 10 is not particularly limited, but is attached to the radiator 40 via an adhesive as shown in FIGS. 6 and 7. The cover body 10 is made of an acrylic resin material having translucency. A diffusion agent can be mixed in the cover body 10 or the surface can be processed so that the LED chip 2 is not directly viewed. In addition, a color conversion agent such as a phosphor can be mixed to improve color rendering.

(Configuration of radiator)
As shown in FIGS. 6 to 8, the basic configuration of the radiator 40 includes a holding case 41 that holds the light emitting unit 5, an inner / outer double cylindrical heat radiating case 42 that fits and holds the holding case 41, and heat dissipation. Unitizing the first heat dissipation ring 43 fixed to the light emitting unit 5 side (first surface) of the case 42 and the base case 44 fixed to the base side (second surface) of the heat dissipation case 42. It is mainly composed of.

  As shown in FIGS. 6 to 8, the holding case 41 includes a large-diameter main body holding portion 41 a that holds and fixes the cover body 10 that guides light from the LED chip 2 to the external space, and the main body holding portion 41 a as a heat dissipation case. And a cylindrical mounting portion 41 b that is fitted and fixed to 42. The material of the holding case 41 is made of a material such as an aluminum material having a high thermal conductivity, a ceramic material, or a resin having a high thermal conductivity, and is configured to guide heat generated during lighting of the LED chip 2 to the heat radiating case 42. Has been.

  As shown in FIGS. 6 to 8, the heat radiating case 42 has a double-cylindrical cylindrical structure that transfers heat generated by the plurality of LED chips 2 and radiates heat to the external space. The material of the heat radiating case 42 is made of, for example, an aluminum material, a ceramic material, or a material excellent in insulation, thermal conductivity, and thermal radiation obtained by forming a film of the surface by anodizing. The heat radiating case 42 includes an inner cylindrical portion 42a that is a first cylindrical member, and an outer cylindrical portion 42b that is a second cylindrical member that is coaxially disposed outside the inner cylindrical portion 42a with a predetermined interval. have. A plurality of heat radiation fins erected in an uneven shape extending in the optical axis direction of the LED chip 2 can be provided on the outer surface wall (first heat radiation portion) facing the external space in the outer cylinder portion 42b.

  As shown in FIGS. 6 and 7, a power supply substrate 35 on which a drive circuit for driving and controlling the LED chip 2 is housed in the inner cylindrical portion 42 a of the heat radiating case 42. By housing the power supply board 35 inside the inner cylinder part 42a, the lengthwise dimension of the radiator 40 can be shortened, so that the outer form of the light emitting device 1 can be reduced in size and size. Will be able to. Various types of electronic components (not shown) such as resistors, diodes, zener diodes, and transistors are mounted on the power supply board 35. In addition, when an installation space can be ensured, the power supply substrate 35 may be disposed on the base part or outside.

  Between the inner cylinder part 42a and the outer cylinder part 42b of the heat radiating case 42, as shown in FIGS. 6 to 8, a long hole (heat radiation channel part) 42c penetrating from one end to the other end in the longitudinal direction of the cylinder part is formed. Has been. The inner cylinder part 42a, the outer cylinder part 42b, and the heat radiation channel part 42c are integrated by extrusion molding. The heat radiation channel portion 42c is divided by six partition walls 42d extending from one end to the other end in the longitudinal direction of the cylinder portion with a predetermined interval in the circumferential direction. The partition walls 42d have a plate shape and are provided radially. The outer cylinder part 42b having the heat radiation channel part 42c and the partition wall 42d constitutes a second heat radiation part that dissipates heat generated during lighting of the plurality of LED chips 2 to the outside. In order to maximize the heat dissipation efficiency, it is desirable to determine the heat dissipation flow path portion 42c and the partition wall 42d so that the air convection speed is increased.

  As shown in FIGS. 6 to 8, the first heat dissipation ring 43 of the heat dissipation case 42 includes a large-diameter circular ring-shaped outer frame 43 a and a small-diameter circular ring shape that is spaced from the outer frame 43 a. The inner frame 43b is connected and fixed by connecting ribs 43c having six U-shaped cross sections. The material of the first heat dissipation ring 43 is made of an insulating resin material such as polycarbonate.

  As shown in FIGS. 6 and 7, the outer edge of the outer frame 43 a of the first heat radiating ring 43 is formed by bending a flange that is fitted and fixed to the end of the outer cylindrical portion 42 b of the heat radiating case 42. Yes. The opening 43d formed between the adjacent connecting ribs 43c is formed corresponding to the heat radiation channel portion 42c of the heat radiation case 42. One inner frame 43b is formed in a divergent shape toward the outer periphery of the heat radiating case 42, and an opening 43d opens the opening of the heat radiating flow path portion 42c of the heat radiating case 42 to the outside.

  As shown in FIG. 8, for example, a reflection mirror 16 having a semicircular arc surface shape serving as a reflection surface can be provided on the outer peripheral portion of the cover body 10 which is one component of the light emitting unit 5. The reflection mirror 16 can be detachably attached to the inner frame 43b of the first heat dissipation ring 43 by a fixture such as a latching clip (not shown).

  As shown in FIGS. 6 to 8, the base case 44 of the heat radiating case 42 has a cylindrical body 44 a that is fitted and fixed in the inner cylindrical portion 42 a of the heat radiating case 42. The cylindrical body 44a is formed in a multistage shape in which a large diameter portion and a small diameter portion are connected by a tapered step portion. Inside the cylindrical body 44a, an attachment boss 44b for fixing the holding case 41 by screwing is extended toward the light emitting portion 5 side. As shown in FIGS. 6 and 7, a part of the power supply board 35 is accommodated in the cylindrical body 44a. A base 38 used for a general light bulb is caulked and fixed to a small diameter portion of the cylindrical body 44a.

  As shown in FIGS. 6 to 8, a second heat dissipation ring 45 is provided on the outer peripheral portion of the cylindrical body 44 a of the base case 44. The installation position of the second heat dissipation ring 45 is provided at a position corresponding to the first heat dissipation ring 43. The second heat dissipating ring 45 has the same material, shape and structure as the first heat dissipating ring 43, and includes a large-diameter circular ring-shaped outer frame 45a and a small-diameter circular ring-shaped inner frame 45b. The gap is connected and fixed by connecting ribs 45c having six U-shaped cross sections. The opening 45d formed between the adjacent connecting ribs 45c is formed corresponding to the heat radiation channel portion 42c of the heat radiation case 42. The inner frame 45b is formed in a divergent shape toward the outer peripheral direction of the heat radiating case 42, and the opening 45d opens the opening of the heat radiating flow path portion 42c of the heat radiating case 42 to the outside.

  By providing these first and second heat radiating ring structures, an air inlet and outlet can be formed in the heat radiating flow path portion 42c of the heat radiating case 42, so that air can be convected. , Can increase the air convection speed. In addition, since air can pass through the heat radiating flow path portion 42c of the heat radiating case 42 while rectifying, natural convection of the air is likely to occur, and the heat generated by the LED chip 2 is easily dissipated. By taking such a structure, the heat dissipation effect can be enhanced regardless of the LED bulb mounting direction.

(Composition of base)
A screw groove 39 having a spiral shape that can be attached to a socket (not shown) is formed on the outer peripheral portion of the base 38 that is caulked and fixed to the small diameter portion of the base case 44. Lead wires 37 a and 37 b that electrically connect the base 38 and the power supply substrate 35 are electrically connected to the base 38. In the illustrated example, an E26 type base for general households is used, but the present invention is not limited to this. For example, an E17 type or E11 type base can be used. In this case, the small diameter portion of the base case 44 may be set to a size corresponding to the size of the E11 die.

  Even in the second embodiment, similarly to the first embodiment, the heat generated from the LED chip 2 is generated by natural convection of the air flowing through the heat radiation channel portion 42c of the radiator 40. Although a configuration for radiating heat is illustrated, for example, the shape, surface area, arrangement form, number of installations, etc. of the heat radiation channel part 42c of the radiator 40 are appropriately set based on the light quantity, luminance, the number of installations, etc. of the LED chip 2. Of course it can be done. The shape of the radiator 40 is not limited to a cylindrical body, and may of course be a cylinder having a polygonal cross-sectional shape such as a triangle, a quadrangle, or a pentagon.

(Configuration of light emitting device drive circuit)
FIG. 9 is a circuit diagram schematically showing a drive circuit of the light emitting device according to the second embodiment. In this figure, the point that differs greatly from the first embodiment is that a thermistor 58 that is a heat detection element is mounted on the drive circuit 50. Note that the components of the drive circuit 50 are not different from those of the first embodiment in the basic configuration. Accordingly, in FIG. 9, the same member names and symbols are assigned to substantially the same members as those in the first embodiment. Therefore, the detailed description regarding these members is omitted.

  A thermistor 58 that is a heat detection element electrically connected to the control unit 54 is mounted on the LED substrate 3. The thermistor 58 is for reducing the current flowing through the LED chip 2 when the LED chip 2 generates excessive heat due to an increase in ambient temperature or the like. The control unit 54 controls the output voltage according to the temperature of the LED substrate 3 and / or the ambient temperature by inputting the temperature signal detected by the thermistor 58. When the temperature of the thermistor 58 increases (the temperature of the LED chip 2 increases and the temperature of the LED substrate 3 increases), the resistance of the thermistor 58 decreases. The controller 54 controls the voltage applied to the LED chip 2 to be low. As a result, the current flowing through the LED chip 2 is reduced, so that the LED chip 2 does not generate excessive heat. With this configuration, the LED chip 2 can be protected so as not to be deteriorated or unlit due to heat generation.

  In the illustrated example, a configuration example using the thermistor 58 that detects the ambient temperature of the LED substrate 3 is illustrated, but the configuration is not limited thereto. Instead of the thermistor 58, for example, a heat sensing element such as a constant current diode, a posistor, or a thermocouple (thermocouple) can be used. Based on the change in the detection output from the thermistor 58, the current supplied to the LED chip 2 by the control unit 54 can be changed, and the emission intensity of the LED chip 2 can be driven and controlled. Further, the emission intensity of the LED chip 2 can be driven and controlled by changing the pulse width of the current supplied to the LED chip 2 by the control unit 54 based on the change in the detection output from the thermistor 58. Of course, the configuration of the drive circuit 50 is not limited to the illustrated example.

(Heat dissipation of light emitting device)
Even in the heat dissipating action of the light emitting device 1 according to the second embodiment, there is no difference from the first embodiment. When the base 38 of the light emitting device 1 is electrically connected to a commercial power source, the DC voltage converted into a DC voltage of a predetermined voltage by the power circuit of the power board 35 is supplied from the electronic components on the power board 35 to the lead wires 36a and 36b. Is applied to each of the plurality of LED chips 2 on the LED substrate 3, and each of the LED chips 2 emits light. Light from the LED chip 2 is incident on the cover body 10 either directly on the cover body 10 or reflected by the reflecting surface 13 a of the reflector 13. The light incident on the cover body 10 is emitted toward the outside of the light emitting device 1 and illuminates the peripheral portion brightly.

  By the way, during the lighting of the LED chip 2, heat is generated by the electric power that has not been converted into light. This heat reaches the radiator 40 via the LED substrate 3 and the insulating sheet 4. The heat diffuses in the radiator 40 and diffuses to the plurality of heat radiation passage portions 42 c of the radiator 40. The heat transmitted to the plurality of heat radiation channel portions 42c is dissipated into the air by heat exchange with air along the heat radiation channel portions 42c. Also, heat from the power supply circuit is dissipated into the air via the radiator 40.

  In the radiator 40 according to the second embodiment, in addition to dissipating the heat generated from the LED chip 2 by natural convection of air flowing through the heat dissipation flow path portion 42c, The holding case 41 and the heat radiating case 42 radiate heat generated from the LED chip 2 as radiant heat. Due to these synergistic effects, it is possible to efficiently dissipate heat generated during lighting of the LED chip 2 to the external space of the light emitting device 1, and the temperature during lighting of the LED chip 2 can be stabilized.

(Assembly procedure of light emitting device)
Next, an example of an assembly procedure of the light emitting device 1 according to the second embodiment will be described with reference to FIGS.

  In assembling the light emitting device 1, the lead wires 36 a and 36 b of the LED substrate 3 are inserted into lead wire insertion holes formed in the holding case 41 and soldered to the power supply substrate 35, and lead wires connected to the base 38. 37a and 37b are soldered to the power supply substrate 35. Next, the entire portion connecting these lead wires 36 and 37 and the power supply substrate 35 is covered with a heat shrinkable tube and heated so as to be in close contact with the power supply substrate 35. The power supply board 35 is inserted and fixed in the heat radiating case 42. Next, the first heat dissipation ring 42 and the base case 44 are fixed to the heat dissipation case 42 with an adhesive. Next, the holding case 41 is fixed to the mounting boss 44b of the base case 44 by screwing. Next, the assembly of the light emitting unit 5 is fixed to the holding case 41 with an adhesive. Subsequently, after the lead wires 37 a and 37 b are soldered to the base 38, the base 38 is caulked and fixed to the base case 44.

  The assembly of the light emitting device 1 is obtained by the above assembling work. In addition, it is desirable that each component of the light emitting device 1 is provided with, for example, a heat radiation coating and / or a heat insulation coating, and assembled through a heat radiation silicon adhesive having a high thermal conductivity.

(Effect of the second embodiment)
According to the light emitting device 1 according to the second embodiment, in addition to the same effects as those of the first embodiment, the following various effects can be obtained.
(1) The light extraction efficiency of the LED chip 2 can be sufficiently ensured.
(2) The lengthwise dimension of the radiator 40 can be shortened, and the light emitting device 1 can be reduced in size and size.
(3) Heat generated by touching and inside the hand is suppressed, and there is no risk of fire, electric shock, or burns.

  As is clear from the above description, in each of the above-described embodiments, the configuration in which the power supply substrate 35 for LED chip drive control is housed in the radiator 20 (40) is illustrated. Is not limited to this, for example, instead of a light emitting device incorporating a power supply substrate for LED chip drive control, an attachment for a lighting device incorporating the power supply substrate is installed on the ceiling, wall surface, etc. of the room Of course, it is possible to adopt a configuration in which the attachment for the incandescent light bulb and the attachment for the lighting device and the light emitting device excluding the power supply substrate for LED chip drive control can be combined, and the initial object of the present invention is Can be fully achieved. Therefore, the present invention is not limited to the above embodiments and modifications, and various design changes can be made within the scope described in each claim.

Claims (15)

A light emitting unit having a plurality of light emitting elements;
A heat sink having a first surface for holding the light emitting unit and a second surface formed on the opposite side of the first surface;
The heat radiator includes a first heat radiating portion that radiates heat generated by the light emitting portion to an outer periphery, and an inner periphery of a hole formed between the first surface and the second surface. A light emitting device comprising: a second heat dissipating part that diffuses.   The light-emitting device according to claim 1, wherein the radiator has a radiation fin on an outer periphery.   The light emitting device according to claim 1, wherein the hole is formed on a central axis of the first surface and the second surface.   2. The light emitting device according to claim 1, wherein a plurality of the holes are formed on concentric circles centering on a central axis of the first surface and the second surface. The light emitting unit has a wiring board on which the plurality of light emitting elements are mounted, and a transparent cover body that covers the plurality of light emitting elements and the wiring board on the first surface,
The light emitting device further includes a housing that holds the second surface of the radiator, a circuit board that drives and controls the plurality of light emitting elements, and a portion of the housing that is opposite to the portion that holds the radiator. The light-emitting device according to claim 1, further comprising: a base that is provided at a portion for supplying electric power to the plurality of light-emitting elements.   The light-emitting device according to claim 1, further comprising a cylindrical lens having a focal point on a line connecting the centers of the plurality of light-emitting elements. The housing has a space portion communicating with the hole of the radiator, and a plurality of communication holes communicating with the space portion,
The light emitting device according to claim 5, wherein each of the plurality of communication holes opens to an external space.   6. The light emitting device according to claim 5, wherein a lead wire for electrically connecting the wiring board and the circuit board is arranged through the hole.   6. The light emitting device according to claim 5, wherein the wiring board is attached to the radiator through an insulating sheet having thermal conductivity.   The light emitting device according to claim 5, wherein the circuit board is provided inside the base. The radiator has a first cylindrical member and a second cylindrical member arranged coaxially with respect to the first cylindrical member,
The light emitting device according to claim 1, wherein the hole is formed between the first cylindrical member and the second cylindrical member.   The light emitting device according to claim 11, wherein the hole is divided into a plurality of portions by a partition extending from one end to the other end.   The light emitting device according to claim 11, wherein a power supply substrate that drives and controls the plurality of light emitting elements is disposed inside the first cylindrical member. A wiring board on which the plurality of light emitting elements are mounted is provided at one end of the first cylindrical member,
The light emitting device according to claim 11, wherein the wiring board is provided with a heat detection element that detects a temperature of the wiring board or an ambient temperature.   The light-emitting device according to claim 14, wherein the plurality of light-emitting elements are driven and controlled based on a change in detection output from the heat detection element.

Images