JP5563407B2 - LED lighting unit - Google Patents

Description

  The present invention relates to an LED lighting unit in which a heat dissipation member is attached to a circuit board on which a light emitting diode (LED) chip is mounted.

  A conventional LED lighting unit of this type will be described with reference to FIGS. As shown in FIG. 6, the LED lighting unit 100 is provided on the circuit board 102 on which the LED chip 101 is mounted, a translucent member 103 that covers the surface of the circuit board 102, and the back surface of the circuit board 102. The heat radiating member 104 is provided. The translucent member 103 includes a lens portion 105 that collects light emitted from the LED chip 101 and a lens holder 106 that holds the lens portion 105, and is formed using a resin such as acrylic. The lens holder 106 is formed with a flange 107 that comes into contact with the peripheral portion of the circuit board 102. The circuit board 102 is housed by the translucent member 103 and the heat radiating member 104 by fastening the translucent member 103 to the heat radiating member 104 through the screw 108 in the screw hole of the flange portion 107.

  In such a conventional LED lighting unit 100, a predetermined gap d is required between the heat dissipation member 104 and the flange portion 107 in order to press the circuit board 102 against the heat dissipation member 104. This gap d may be larger than a desired dimension due to manufacturing errors of the circuit board 102 and the translucent member 103. If the translucent member 103 is fastened to the heat radiating member 104 with the screw 108 under such circumstances, the flange portion 107 is greatly deformed and easily cracked as shown in FIG. difficult. Therefore, the circuit board 102 may not be brought into close contact with the heat radiating member 104, and a thermal resistance is generated between the circuit board 102 and the heat radiating member 104, so that the heat generated from the LED chip 101 can be sufficiently radiated. There was something I couldn't do.

  Another example of the LED lighting unit is one in which a circuit board on which an LED chip is mounted is directly fixed to a heat radiating member with screws (see, for example, Patent Document 1). However, in such a configuration, a space for screw holes is required on the circuit board, and the board size becomes larger than the above.

JP 2007-220465 A

  The present invention has been made to solve the above problems, and in an LED lighting unit that fixes a circuit board on which an LED chip is mounted by fastening a light-transmitting member and a heat radiating member, the circuit board is attached to the heat radiating member. It aims at improving the heat dissipation characteristic of LED by improving adhesiveness.

The LED lighting unit of the present invention includes a circuit board on which an LED chip is mounted, a translucent member that covers the surface of the circuit board and through which light emitted from the LED chip passes, and a back surface of the circuit board. In the LED lighting unit provided with a heat radiating member to be attached , provided on the outer side of the circuit board, fastening means for fastening the light transmissive member to the heat radiating member with screws , provided on the inner side of the fastening means, An elastic member sandwiched between the circuit board and the translucent member in a state in which the translucent member is fastened to the heat radiating member by the fastening means, and the elastic member is in a state in which the fastening means is fastened The circuit board is elastically deformed and acts to press the circuit board against the heat radiating member by the repulsive force.

  In the LED lighting unit, the circuit board includes a metal plate having high thermal conductivity, an insulating film formed on the metal plate, and a circuit pattern for mounting the LED chip formed on the insulating film. It is preferable to comprise.

  In this LED lighting unit, it is preferable that the contact surface between the circuit board and the heat dissipation member is smoothed.

  In this LED lighting unit, it is preferable that grease having high thermal conductivity be interposed between the circuit board and the heat dissipation member.

  According to the LED lighting unit of the present invention, the circuit board can be pressed against the heat dissipating member by the repulsive force of the elastic member sandwiched between the circuit board and the translucent member, so that both can be brought into close contact with each other. It is possible to reduce the thermal resistance between the heat radiating member and efficiently radiate the heat generated from the LED chip through the heat radiating member. Further, since the heat dissipation of the LED chip is improved, a large current can be passed through the LED chip, and the light output can be increased. In addition, since the circuit board can be housed with a translucent member and a heat radiating member to protect the LED chip from the outside, it is possible to prevent damage to the LED due to physical impact or electrostatic breakdown of the LED due to human contact. it can. In addition, since the circuit board can be housed while absorbing the dimensional error due to manufacturing variations of the translucent member and the circuit board by the elastic member, even if the heat radiating member and the translucent member are strongly tightened, the translucency The deformation and cracking of the member are reduced.

The external view which looked at the state which mounted | wore the ceiling with the LED lighting unit which concerns on one Embodiment of this invention from the downward direction. The partial cross section side view of the unit. The sectional side view of the circuit board which mounted the LED chip of the unit. (A) is a sectional side view of the unit with the translucent member attached to the circuit board through the packing, and (b) is a state in which the circuit board with the translucent member attached is placed on the instrument body. (C) is a sectional side view in the state which fastened the translucent member to the instrument main body with the bis | screw. (A) thru | or (c) is a sectional side view which shows the modification of the said LED illumination unit. The sectional side view of the conventional LED lighting unit. The enlarged view of the X section of FIG. 6 which shows the state which the crack occurred in the translucent member of the unit.

  An LED lighting unit according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the LED lighting unit 1 is a downlight type lighting fixture and is used by being embedded in a ceiling portion of a building such as an office or a factory. The LED lighting unit 1 includes a circuit board 3 on which a plurality of LED chips 2 are mounted, a translucent member 4 that covers the surface of the circuit board 3 and through which light emitted from the LED chip 2 passes, and a circuit board 3. And an instrument body 5 for holding the device. The appliance main body 5 is attached to the back surface of the circuit board 3 as a heat radiating member, and dissipates heat generated from the LED chip 2. The fixture body 5 is provided with a reflector 6 that reflects light emitted from the LED chip 2.

  Further, the LED lighting unit 1 includes a screw 7 (fastening means) that fastens the translucent member 4 to the fixture body 5 and an elastic packing 8 provided between the circuit board 3 and the translucent member 4. (Elastic member). Furthermore, the LED lighting unit 1 has a holder 10 for fixing the unit to the ceiling 9, and when the unit is inserted into the opening 9a of the ceiling 9, the holder 10 holds the periphery of the opening 9a. ing. The holder 10 is provided at an outer edge portion of the light emitting side of the reflecting plate 6.

  For example, a white LED chip can be used as the LED chip 2. In this case, a LED element that emits blue light and a phosphor that converts the wavelength of blue light into yellow light is preferably used. The emission color of the LED chip 2 is not limited to white, and may be, for example, yellow or orange. Further, the number of LED chips 2 is not particularly limited, and may be set as appropriate according to the specifications of the unit 1.

  The translucent member 4 includes a lens portion 41 that collects light emitted from the LED chip 2 and a lens holder 42 that holds the lens portion 41, and is formed using a translucent resin such as acrylic or polycarbonate. Is done. The lens part 41 and the lens holder 42 may be integrally formed, or may be formed so as to be separable from each other. The lens portion 41 is configured by a hybrid lens body that is convex in a direction opposite to the light extraction direction, and is disposed corresponding to each of the plurality of LED chips 2. The lens holder 42 is formed with a flange portion 43 extending in a direction away from the lens portion 41, and the flange portion 43 has a through hole through which the screw 7 passes.

  The instrument body 5 is formed using a member having excellent heat dissipation, such as aluminum. When an aluminum material is used for the instrument body 5, a die casting method can be used as a method for forming the instrument body 5. The instrument body 5 has a substantially cylindrical outer shape, and has a screw hole for the screw 7 at the bottom 51 thereof. The contact surface between the instrument body 5 and the circuit board 3 is preferably smoothed by buffing or the like. As a result, the surfaces of the circuit board 3 and the instrument body 5 have innumerable irregularities at the time of molding. However, such irregularities are eliminated so that the instrument body 5 and the circuit board 3 can be contacted without interposing an air layer. The thermal resistance can be reduced. A plurality of heat radiation fins 52 are provided on the outer peripheral portion of the instrument body 5. The top plate portion 53 of the instrument body 5 is provided with a power supply device 11 for lighting the LED chip 2, and the power supply device 11 is connected to the circuit board 3 by the power supply line 12.

  The packing 8 is sandwiched between the circuit board 3 and the flange portion 43 of the translucent member 4 in a state where the translucent member 4 is fastened to the instrument main body 5 by screws 7, A ring-shaped one is used. For example, foamed silicon can be used as the material of the packing 8. The packing 8 is elastically deformed when the screw 7 is in a fastened state, and acts to press the circuit board 3 against the instrument body 5 by its repulsive force.

  As shown in FIG. 3, the circuit board 3 is mounted with a metal plate 31 with high thermal conductivity, an insulating film 32 formed on the metal plate 31, and an LED chip 2 formed on the insulating film 32. And a circuit pattern 33 for this purpose. The metal plate 31 is formed using, for example, an aluminum material. The circuit pattern 33 is made of, for example, a metal film such as titanium (Ti), gold (Au), or copper (Cu), and is electrically connected to the electrode portion 21 of the LED chip 2. For the formation of the circuit pattern 33, for example, a vapor deposition method, a plating method, a printing method, or the like can be used. By using such a circuit board 3, heat generated from the LED chip 2 can be efficiently conducted to the instrument body 5 and the heat dissipation characteristics of the LED chip 2 can be enhanced.

  Next, a procedure for attaching the circuit board 3 and the translucent member 4 to the fixture body 5 in the LED lighting unit 1 configured as described above will be described with reference to FIG. First, as shown in FIG. 4A, the packing 8 is disposed between the circuit board 3 on which the LED chip 2 is mounted and the flange portion 43 of the translucent member 4, and the circuit board 3 and the translucent member 4. Are bonded to the packing 8 using an adhesive, and the translucent member 4 is anchored to the circuit board 3. Next, as shown in FIG. 4B, the circuit board 3 is placed on the attachment surface of the bottom 51 of the instrument body 5. At this time, if a high thermal conductivity grease is interposed between the circuit board 3 and the instrument body 5, the thermal resistance between the circuit board 3 and the instrument body 5 can be reduced. Then, the screw 7 is passed through the through hole of the flange portion 43 to tighten the screw 7. Here, before the screw 7 is tightened, a gap d is provided between the end of the flange 43 and the instrument body 5. By tightening the screw 7, the packing 8 contracts as shown in FIG. 4C, and at the same time, the circuit board 3 is pressed against the instrument body 5 by the elastic force of the packing 8. When the screw 7 is completely tightened, the gap d is eliminated, and the end of the flange 43 is brought into contact with the instrument body 5.

  As described above, according to the LED lighting unit 1 according to the present embodiment, the circuit board 3 is pressed against the instrument body 5 by the repulsive force of the elastic member sandwiched between the circuit board 3 and the translucent member 4. Since the heat resistance between the circuit board 3 and the instrument body 5 is reduced, the heat generated from the LED chip 2 can be efficiently radiated through the instrument body 5. Further, since the heat dissipation of the LED chip 2 is improved, a large current can be passed through the LED chip 2 and the light output can be increased. Further, since the circuit board 3 can be housed by the translucent member 4 and the instrument body 5 and the LED chip 2 can be protected from the outside, when assembling or repairing the instrument, The electrostatic breakdown of the LED due to human contact can be prevented. In addition, since the circuit board 3 can be housed while the dimensional error due to manufacturing variations of the translucent member 4 and the circuit board 3 is absorbed by the elastic member, the instrument body 5 and the translucent member 4 are strongly tightened. In addition, deformation and cracking of the translucent member 4 are reduced.

  Next, a modification of the LED lighting unit will be described with reference to FIG. As shown in FIG. 5A, the LED lighting unit 1 according to this modification includes a spring body 13 including a pair of leaf springs provided on the surface of the circuit board 3 instead of the packing 8. A locking piece 14 to be inserted between the leaf springs of the spring body 13 is provided on the back side of the translucent member 4. The locking piece 14 is formed to project from the lens holder 42 of the translucent member 4 and has a convex tip. The spring body 13 has a configuration in which the respective leaf springs are arranged to face each other and the tip portions of each are bent into a bag shape so as to sandwich the convex portion of the locking piece 14 inserted between the leaf springs. It has become. The spring body 13 is formed using a metal such as copper, and is fixed to the surface of the circuit board 3 by soldering or the like.

  When attaching the circuit board 3 and the translucent member 4 to the fixture body 5 in such an LED lighting unit 1, first, as shown in FIG. 5 (b), the circuit board 3 and the translucent member 4 And the translucent member 4 is anchored to the circuit board 3 by inserting and holding the locking piece 14 of the translucent member 4 into the spring body 13. Next, as shown in FIG. 5C, the circuit board 3 is placed on the mounting surface of the bottom 51 of the instrument body 5, and the screw 7 is tightened by passing the screw 7 through the through hole of the flange 43. By tightening the screws 7, the spring pieces of the spring body 13 are deformed outward, and at the same time, the circuit board 3 is pressed against the instrument body 5 by the elastic force of the spring pieces. When the screw 7 is completely tightened, the end of the flange 43 is brought into contact with the instrument body 5.

  Even with such an LED lighting unit 1, the same effect as described above can be obtained. In addition, the translucent member 4 can be locked to the circuit board 3 simply by inserting the locking piece 14 of the translucent member 4 into the spring body 13 provided on the circuit board 3, so that the adhesive holding is maintained. Compared to the case, the assembly man-hour can be reduced.

  In addition, this invention is not restricted to the structure of the said embodiment, A various deformation | transformation is possible in the range which does not change the meaning of invention. For example, although the example which comprised the instrument main body 5 as a heat radiating member was shown above, it is not restricted to this, You may make it provide a heat radiating member separately from the instrument main body 5. FIG.

  Further, in the case of the LED light source module, a configuration without the flange portion 43 (an anchoring portion) is common from the configuration of the first embodiment shown in FIG. In this case, the circuit board 3 is sandwiched between the translucent member 4 without the flange 43 and the aluminum die-casting tray, and if necessary, a heat dissipation sheet is placed on the tray, and the translucent member 4 and the tray are screwed together. The LED light source module is configured by stopping or the like. According to the invention of the present application, the circuit board 3 can be pressed against the instrument body 5 (heat dissipating member) by the repulsive force of the packing 8 (elastic member) to improve the heat dissipating characteristics, so that when used as an LED light source module In addition, it is possible to omit the aluminum die casting tray, which has been conventionally required. Moreover, the assembly property and rigidity of an LED light source module can be improved because there is no tray.

DESCRIPTION OF SYMBOLS 1 LED lighting unit 2 LED chip 3 Circuit board 31 Metal plate 32 Insulating film 33 Circuit pattern 4 Translucent member 5 Instrument main body (heat radiating member)
7 Screws (fastening means)
8 Packing (elastic member)
13 Spring body (elastic member)

Claims (4)

A circuit board having an LED chip mounted thereon, a translucent member through which light emitted from the LED chip passes, covering the surface of the circuit board, and a heat dissipation member attached to the back surface of the circuit board In LED lighting unit,
Fastening means that is provided outside the circuit board and fastens the light transmissive member to the heat radiating member with screws .
An elastic member provided inside the fastening means, and sandwiched between the circuit board and the translucent member in a state where the translucent member is fastened to the heat dissipation member by the fastening means,
The LED lighting unit according to claim 1, wherein the elastic member is elastically deformed when the fastening means is in a fastening state, and acts to press the circuit board against the heat radiating member by a repulsive force.   The circuit board includes a metal plate having high thermal conductivity, an insulating film formed on the metal plate, and a circuit pattern formed on the insulating film for mounting the LED chip. The LED lighting unit according to claim 1.   The LED lighting unit according to claim 1, wherein a contact surface between the circuit board and the heat radiating member is smoothed.   The LED lighting unit according to any one of claims 1 to 3, wherein grease having high thermal conductivity is interposed between the circuit board and the heat dissipation member.

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