JP2018156796A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device which can facilitate heat radiation of a light emitting element effectively.SOLUTION: A lighting device 14 includes: a circuit board 21 having a wiring pattern 26 on its surface; a light emitting element 24 mounted on the surface of the circuit board 21 and connected to the wiring pattern 26; a holder 22 supporting a rear surface of the circuit board 21; and a radiator 42 which is formed by a material having heat conductivity higher than that of the holder 22, fixed to the holder 22, and contacts with the circuit board 21 at a position away from the wiring pattern 26.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a lighting device including a circuit board having a wiring pattern on a surface thereof, a light emitting element mounted on the surface of the circuit board and connected to the wiring pattern, and a holder for supporting the back surface of the circuit board.

  Patent document 1 discloses the light-emitting device used for the illumination of a vehicle interior. The light emitting device includes a circuit board supported by the holder. A light emitting element (LED element) and an electronic component are mounted on the circuit board. A connection terminal is connected to the circuit board.

JP 2012-089602 A

  Electric power is supplied from the connection terminal to the electronic component on the circuit board. The electronic component controls power supply to the light emitting element. Therefore, the light emitting element is greatly separated from the connection terminal. The heat dissipation terminal cannot sufficiently contribute to the heat dissipation of the light emitting element.

  This invention is made | formed in view of the said actual condition, and it aims at providing the illuminating device which can accelerate | stimulate the heat dissipation of a light emitting element effectively.

  According to the first aspect of the present invention, a circuit board having a wiring pattern on the front surface, a light emitting element mounted on the surface of the circuit board and connected to the wiring pattern, and a holder for supporting the back surface of the circuit board And a radiator that is formed of a material having a higher thermal conductivity than the holder, is fixed to the holder, and contacts the circuit board at a position away from the wiring pattern.

  According to the second aspect, in addition to the configuration of the first side surface, the heat radiator has a protruding portion that protrudes from a surface that receives the circuit board and is received in a receiving hole arranged in the circuit board.

  According to the third aspect, in addition to the configuration of the second side surface, the receiving hole is positioned away from the light emitting element at a distance shorter than the distance between the light emitting element and the through hole connected to the conductive terminal. Be placed.

  According to the fourth aspect, in addition to the configuration of the third side surface, the receiving hole is configured by a pair arranged symmetrically with respect to a symmetry plane that bisects the surface of the circuit board.

  According to the 5th side, in addition to the composition of the 4th side, the radiator is connected mutually other than the projection part.

  According to the sixth aspect, in addition to the configuration of any one of the second to fifth aspects, the heat radiating body has an extended portion connected to the protruding portion and having a larger surface area than the protruding portion.

  According to the seventh aspect, in addition to the configuration of the first side surface, the radiator has a surface that extends flush with the surface that receives the circuit board.

  According to the eighth aspect, in addition to the configuration of the seventh side, the circuit board contacts the heat radiating body on the back side of the light emitting element.

  According to the ninth aspect, in addition to the configuration of any one of the first to eighth aspects, the radiator is embedded in the holder.

  According to the tenth aspect, in addition to the configuration of the ninth aspect, the heat radiator is fixed to the holder based on insert molding.

  According to the first aspect, the heat generated based on the electrical resistance of the light emitting element is transmitted from the circuit board to the holder through the heat radiating body and is radiated from the holder. The heat sink promotes heat transfer from the circuit board to the holder.

  According to the second aspect, the radiator can be formed with a simple configuration. The protrusion can help to position the circuit board.

  According to the third aspect, efficient heat dissipation from the light emitting element is realized.

  According to the fourth aspect, efficient heat dissipation from the light emitting element is realized.

  According to the fifth aspect, since the heat radiating body is integrated into one, the heat radiating body can be easily arranged as compared with the case where they are individually arranged.

  According to the sixth aspect, heat can be efficiently radiated from the extended portion.

  According to the seventh aspect, the radiator can be in contact with the back surface of the circuit board over a wide area. Thus, efficient heat dissipation from the circuit board is realized.

  According to the eighth aspect, heat dissipation can be further enhanced.

  According to the ninth aspect, the heat of the radiator can be efficiently transmitted to the holder. Thus, heat dissipation of the light emitting device can be further promoted.

  According to the tenth aspect, the radiator can be easily fixed to the holder.

It is a schematic diagram which shows schematically the door trim of a motor vehicle. 1A is an exploded perspective view schematically showing a configuration of a first lighting device, FIG. 1B is a perspective view with a cover removed, and FIG. It is an expansion vertical sectional view of the 1st lighting device. It is the whole perspective view which shows the structure of a 2nd illuminating device schematically. It is the whole holder schematic diagram which shows schematically the heat radiator which concerns on other embodiment. It is an expanded vertical sectional view of the 1st illuminating device which shows schematically the heat radiator which concerns on other embodiment.

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

  FIG. 1 schematically shows a configuration of a lighting system mounted on an automobile. The lighting system 11 is embedded in the left and right door trims 12 to illuminate the door inside handle 13 when lit, and embedded in the left and right door armrests 15, respectively, and the edge of the door armrest 15 is lit when lit. And a second illumination device 16 that illuminates. The first lighting device 14 and the second lighting device 16 are connected to an automobile control unit (ECU) 17 via LIN communication. The control unit 17 controls turning on and off of the first lighting device 14 and the second lighting device 16. According to the LIN communication, the first lighting device 14 and the second lighting device 16 can be connected in series or in parallel with one wire harness 18 when connecting to the control unit 17.

  As shown in FIG. 2, the first lighting device 14 includes a prismatic holder 22 that supports the circuit board 21, and a cover 23 that is fitted into the holder 22 and sandwiches the circuit board 21 between the holder 22. Prepare. The holder 22 and the cover 23 are formed from, for example, an insulating resin molded body. The holder 22 is fixed to the constituent material of the door trim 12.

  On the surface of the circuit board 21, one light emitting element 24 and one or more electronic components 25 that contribute to light emission of the light emitting element 24 are mounted. The light emitting element 24 and the electronic component 25 are soldered to the wiring pattern 26, for example. For example, a reflow process is used for soldering. The light emitting element 24 is composed of, for example, an LED (light emitting diode) element. The LED element emits surface light, for example.

  The wiring pattern 26 includes a plurality of (here, four) through holes 26a. The through hole 26a is formed of a conductive wall that is continuous from the conductive material of the wiring pattern 26 and surrounds, for example, a cylindrical space. The base material of the circuit board 21 is formed from, for example, an insulating resin material or a ceramic material.

  The holder 22 has a bottom surface (support surface) 27 that is configured as a plane and supports the back surface of the circuit board 21, and an enclosure wall 28 that surrounds the bottom surface 27 and protrudes forward from the bottom surface 27. The bottom surface 27 has a shape equal to the contour of the circuit board 21. The enclosing wall 28 is a pair of first wall surfaces 29a and 29b that are perpendicular to the bottom surface 27 and face each other up and down, and a pair that is perpendicular to the bottom surface 27 and that faces each other right and left and connects the upper and lower first wall surfaces 29a and 29b. Second wall surfaces 31a and 31b. In this way, a flat rectangular parallelepiped space in contact with the bottom surface 27 is defined inside the enclosure wall 28.

  The enclosure wall 28 is defined with an attachment surface 32 that extends parallel to the bottom surface 27 at a specific distance from the bottom surface 27 and surrounds the entire circumference of the bottom surface 27. A space surrounded by the surrounding wall 28 forms a recess with respect to the mounting surface 32. When the circuit board 21 is accommodated in the recess and the back surface of the circuit board 21 is entirely overlapped with the bottom surface 27, the first wall surfaces 29 a and 29 b and the second wall surfaces 31 a and 31 b are in contact with the outer edges of the four sides of the circuit board 21. The parallel movement of the circuit board 21 can be guided in the vertical direction of the bottom surface 27. The holder 22 supports the back surface of the circuit board 21 at the bottom surface 27. The bottom surface 27 functions as a support surface that supports the back surface of the circuit board 21.

  Four conductive terminals 33 protrude from the bottom surface 27. The conductive terminal 33 includes, for example, a power supply terminal and a signal terminal. The conductive terminal 33 is formed from a linear conductive material. Each conductive terminal 33 includes a tip having a so-called press-fit shape. The arrangement of the four conductive terminals 33 reflects the arrangement of the through holes 26 a arranged on the surface of the circuit board 21. That is, the four conductive terminals 33 are arranged in plane symmetry with respect to a symmetry plane AP that bisects the bottom surface 27. When the back surface of the circuit board 21 is overlapped with the bottom surface 27, the conductive terminal 33 penetrates the through hole 26a. The conductive terminal 33 fixes the circuit board 21 to the bottom surface by the action of press fit.

  Upper and lower two notches 34 are defined in each of the second wall surfaces 31a and 31b. The notch 34 is recessed from the second wall surfaces 31a and 31b. The notch 34 partitions one end on the bottom surface 27 side from the virtual plane that is parallel to the bottom surface 27 and is separated from the bottom surface 27 by a distance equal to the thickness of the circuit board 21, and is separated from the virtual plane to the open end side at a specific distance. Partition the other end at the same position.

  The cover 23 has a decorative plate 37 including a lens 36. The lens 36 is integrated with a decorative plate 37, for example. The cover 23 is light transmissive at least in the portion of the lens 36. The decorative plate 37 includes an upper edge region 38 a that covers the upper mounting surface 32 of the holder 22 and a lower edge region 38 b that covers the lower mounting surface 32 of the holder 22. A plate-like attachment piece 39 extending vertically from the decorative plate 37 to the rear is integrally formed on the left and right edges of the decorative plate 37 between the upper edge region 38a and the lower edge region 38b. The attachment piece 39 is connected to the edge of the decorative plate 37 by one ridge line 39a and allows predetermined elastic deformation.

  Two upper and lower protrusions 41 are formed on the outer surface of the attachment piece 39. The protrusions 41 are arranged at positions corresponding to the notches 34 of the holder 22. When the cover 23 is fitted into the holder 22, the attachment piece 39 comes into contact with the corresponding second wall surfaces 31 a and 31 b. The protrusions 41 enter the corresponding cutouts 34. The protruding body 41 engages with the notch 34 to prevent the cover 23 from falling off the holder 22. The rear end 39 b of the attachment piece 39 extends parallel to the ridge line 39 a and contacts the surface of the circuit board 21, and sandwiches the circuit board 21 between the bottom surface 27 of the holder 22.

  The first lighting device 14 includes a radiator 42 that is formed of a material having a higher thermal conductivity than the holder 22 and is fixed to the holder 22. The heat radiating body 42 forms a cylindrical piece (protruding portion) 43 that protrudes from the surface that receives the circuit board 21. The cylindrical piece 43 is configured by a pair arranged symmetrically with respect to a symmetry plane AP that bisects the surface of the bottom surface 27. The radiator 42 may be formed from a metal material such as copper or aluminum.

  The circuit board 21 is formed with receiving holes 44 corresponding to the cylindrical pieces 43. The receiving hole 44 is disposed at a position away from the wiring pattern 26. The receiving hole 44 is disposed at a position away from the light emitting element 24 by a distance shorter than the distance between the light emitting element 24 and the through hole 26a. The receiving holes 44 are configured as a pair arranged symmetrically with respect to a symmetry plane SP that bisects the surface of the circuit board 21. The cylindrical piece 43 of the radiator 42 is received in the receiving hole 44. The outer periphery of the cylindrical piece 43 is in close contact with the inner wall surface of the receiving hole 44. The cylindrical piece 43 may be press-fitted into the receiving hole 44. The cylindrical piece 43 may have a press-fit tip.

  As shown in FIG. 3, the holder 22 supports the back surface of the circuit board 21 with the bottom surface 27. Here, the circuit board 21 is overlaid on the bottom surface 27 of the holder 22 over the entire surface. The light emitting element 24 is covered with a lens 36. The light from the light emitting element 24 is spread by the lens 36.

  A connector 45 is established on the holder 22. The connector 45 is configured as a female connector. The connector 45 defines a space 46 that receives the male connector. Each conductive terminal 33 protrudes into the space 46. The conductive terminal 33 has a first linear portion 33 a that protrudes from the bottom surface 27 and extends perpendicularly to the bottom surface 27, and a second linear portion 33 b that is bent from the first linear portion 33 a and extends parallel to the bottom surface 27 in the space 46. . The conductive terminal 33 is embedded in the holder 22. For embedding, for example, insert molding is used. A male connector coupled to the wire harness 18 is inserted into the connector 45. The male connector may be detachably coupled to the connector 45.

  The radiator 42 is embedded in the holder 22. The radiator 42 is fixed to the holder 22 based on insert molding. The heat radiating body 42 is connected to the columnar piece 43 and has an extended portion 49 having a larger surface area than the columnar piece 43. The extension 49 may be embedded in the holder 22, for example. The expansion portions 49 are connected to each other within the holder 22. The heat dissipating body 42 includes a connecting body 51 that is continuous with the expanding portion 49 and connects the expanding portions 49 to each other.

  As shown in FIG. 4, the second lighting device 16 is configured in the same manner as the first lighting device 14. However, in the second lighting device 16, the light guide tube 53 is coupled to the cover 52 instead of the lens 36. The light guide tube 53 is formed as a tube having a circular cross section. For example, the light guide tube 53 guides light in the linear direction and emits light in the radial direction of each cross section. The light guide tube 53 provides linear illumination. The configuration other than the light guide tube 53 is the same as that of the first lighting device 14.

  Next, the operation of this embodiment will be described. In the assembly, the light emitting element 24 and the electronic component 25 are mounted on the surface of the circuit board 21. The circuit board 21 is assembled in the holder 22. In assembling, the circuit board 21 is aligned with the enclosure wall 28 of the holder 22. The back surface of the circuit board 21 faces the bottom surface 27 of the holder 22. The through holes 26a are positioned corresponding to the individual conductive terminals 33. Similarly, the columnar piece 43 of the radiator 42 is positioned with respect to each receiving hole 44. When the circuit board 21 is pushed inside the enclosure wall 28, the movement of the circuit board 21 is guided along the first wall surfaces 29a and 29b and the second wall surfaces 31a and 31b. The conductive terminal 33 penetrates the corresponding through hole 26a. A conductive connection is ensured between the conductive terminal 33 and the through hole 26a. The cylindrical piece 43 of the radiator 42 penetrates through the receiving hole 44 of the circuit board 21. The cylindrical piece 43 is in close contact with the base material of the circuit board 21. The circuit board 21 is fixed to the holder 22 by the action of press fit.

  Next, the cover 23 is fitted into the holder 22. The attachment piece 39 of the cover 23 is aligned inside the enclosure wall 28 of the holder 22. The upper and lower ends of the attachment piece 39 are guided by the first wall surfaces 29 a and 29 b of the enclosure wall 28. When the cover 23 is pushed toward the holder 22, the attachment piece 39 causes the protrusion 41 to enter the notches 34 of the second wall surfaces 31a and 31b while elastically deforming inward. When the rear end 39 b of the attachment piece 39 hits the surface of the circuit board 21, the protrusion 41 engages with the notch 34. Thus, the cover 23 is attached to the holder 22. The circuit board 21 is sandwiched between the holder 22 and the cover 23.

  In the present embodiment, the radiator 42 is fixed to the holder 22. The radiator 42 is formed of a material having a higher thermal conductivity than the holder 22. Heat generated based on the electrical resistance of the light emitting element 24 is transmitted from the circuit board 21 to the holder 22 through the heat radiating body 42 and is radiated from the holder 22. The heat radiator 42 promotes heat transfer from the circuit board 21 to the holder 22. Since the heat radiator 42 contacts the circuit board 21 at a position deviated from the wiring pattern 26, a short circuit of the wiring can be avoided.

  The radiator 42 has a cylindrical piece 43 that protrudes from the bottom surface 27 of the holder 22 and is received in the receiving hole 44 arranged in the circuit board 21. The heat radiator 42 can be formed with a simple configuration. The cylindrical piece 43 can be useful for positioning the circuit board 21.

  The receiving hole 44 is disposed at a position away from the light emitting element 24 by a distance shorter than the distance between the light emitting element 24 and the through hole 26a. Therefore, efficient heat dissipation from the light emitting element 24 is realized.

  The receiving holes 44 are configured as a pair arranged symmetrically with respect to a symmetry plane SP that bisects the surface of the circuit board 21. Therefore, efficient heat dissipation from the light emitting element 24 is realized.

  The radiators 42 are connected to each other except for the cylindrical pieces 43. Since the heat radiating body 42 is integrated into one, the heat radiating body 42 can be easily arranged as compared with the case where they are individually arranged. Assembling workability is improved.

  The heat radiating body 42 is connected to the columnar piece 43 and has an extended portion 49 having a larger surface area than the columnar piece 43. Heat can be efficiently radiated from the extension 49.

  The radiator 42 is embedded in the holder 22. The heat of the radiator 42 can be efficiently transmitted to the holder 22. In this way, heat dissipation of the light emitting element 24 can be further promoted. Since the heat radiator 42 is fixed to the holder 22 based on insert molding, the heat radiator 42 can be easily fixed to the holder 22.

  FIG. 5 schematically shows a radiator 54 according to another embodiment. The radiator 54 has a surface 54 a that extends flush with the bottom surface 27 of the holder 22. The heat radiator 54 is embedded in the holder 22. The radiator 42 is fixed to the holder 22 based on insert molding. The circuit board 21 contacts the heat radiating body 54 on the back side of the light emitting element 24. The radiator 42 contacts the back surface of the circuit board 21 over a wide area. Thus, efficient heat dissipation from the circuit board 21 is realized.

  In this embodiment, since the circuit board 21 contacts the heat radiating body 54 on the back side of the light emitting element 24, the heat dissipation is further improved. Since the radiator 54 is embedded in the holder 22, the heat of the radiator 42 is efficiently transmitted to the holder 22. Since the radiator 54 is fixed to the holder 22 based on insert molding, the radiator 54 can be easily fixed to the holder 22.

  DESCRIPTION OF SYMBOLS 14 ... Illuminating device (1st illuminating device), 16 ... Illuminating device (2nd illuminating device), 21 ... Circuit board, 22 ... Holder, 24 ... Light emitting element, 26 ... Wiring pattern, 26a ... Through hole, 27 ... Circuit board Receiving surface (bottom surface), 33 ... conductive terminal, 42 ... radiator, 43 ... protrusion (column piece), 44 ... receiving hole, 49 ... expansion portion, 54 ... radiator, 54a ... surface, SP ... (circuit board) A) symmetry plane.

Claims (10)

A circuit board having a wiring pattern on the surface;
A light emitting element mounted on the surface of the circuit board and connected to the wiring pattern;
A holder for supporting the back surface of the circuit board;
An illuminating device comprising: a heat radiator formed of a material having higher thermal conductivity than the holder, fixed to the holder, and contacting the circuit board at a position away from the wiring pattern.   The lighting device according to claim 1, wherein the heat dissipating member has a protruding portion that protrudes from a surface that receives the circuit board and is received in a receiving hole arranged in the circuit board.   3. The lighting device according to claim 2, wherein the receiving hole is disposed at a position separated from the light emitting element by a distance shorter than a distance between the light emitting element and a through hole connected to the conductive terminal. A lighting device.   The lighting device according to claim 3, wherein the receiving hole is configured by a pair arranged symmetrically with respect to a symmetry plane that bisects the surface of the circuit board.   The lighting device according to claim 4, wherein the heat dissipating members are connected to each other except for the protruding portion.   6. The lighting device according to claim 2, wherein the heat dissipator includes an extended portion that is connected to the protruding portion and has a larger surface area than the protruding portion. .   The lighting device according to claim 1, wherein the heat dissipating member has a surface that is flush with a surface that receives the circuit board.   The lighting device according to claim 7, wherein the circuit board is in contact with the heat radiating body on a back side of the light emitting element.   The lighting device according to claim 1, wherein the heat radiating body is embedded in the holder. The lighting device according to claim 9, wherein the heat radiator is fixed to the holder based on insert molding.