JP2012146552A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device with high luminance in which light emitted from an LED element is not prevented, heat from the LED element is discharged efficiently, and light distribution of an LED bulb is improved.SOLUTION: The lighting device is composed of a light emitting element emitting light, a substrate on which the light emitting element is mounted, a heat radiation plate on which the substrate is mounted and radiates the heat generated from the light emitting element, and a globe which covers the light emitting element, the substrate, and the heat radiation plate and transmits the light emitted from the light emitting element. The heat radiation plate contacts an inner wall of the globe at least at a region other than an edge part.

Description

  The present invention relates to a lighting device using a light emitting element.

  In recent years, for the purpose of replacing conventional incandescent bulbs or bulb-type fluorescent lamps, LED bulbs using light-emitting elements that can be driven with low power consumption, such as light-emitting diodes (hereinafter referred to as LEDs) and organic EL, Research and development are progressing, such as improving luminous efficiency, downsizing, and extending life.

  FIG. 9 is a schematic cross-sectional view showing the overall configuration of a commercially available LED bulb 900. The LED bulb 900 includes a globe 91, an LED package 92, an LED package mounting board 93, a base 94 for mounting the LED package mounting board, a heat sink 95, an insulating ring 96, a power supply board 97, a sealing resin 98, a base 99, a lead, and leads. With lines. The globe 91 that houses the LED package is joined to the base 94 to which the LED package mounting board is attached at the end, and the LED package 92 is mounted on the LED package mounting board 93 and is almost the same as the base 94 to which the LED package mounting board is attached. Located in the center.

  If the LED light bulb 900 attempts to secure a total luminous flux equivalent to that of a conventional incandescent light bulb, the input power to the LED element increases, and the temperature of the LED element during lighting becomes excessively high. Due to this temperature rise, the luminous efficiency of the LED element is lowered, and in order to compensate for the lowered amount, the input power to the LED element is further increased, and a vicious cycle is caused in which the temperature of the LED element further rises.

  Therefore, in order to solve this problem, there is a method of efficiently transferring the heat generated from the LED element to the heat sink 95 and dissipating the heat from the heat sink 95. However, as the brightness of the LED bulb 900 itself increases, heat dissipation cannot be achieved in time only from the heat sink 95. In addition to the heat sink 95, the LED bulb 900 can be considered as a path for the heat transfer of the globe 91 or the base 99, but the material used as the globe 91 has a thermal conductivity with respect to the base 99 formed of metal. Since it is low, there is the present condition that it does not function so much as a heat dissipation member.

  In response to this problem, for example, in Patent Document 1, a translucent layer made of a translucent material having a thermal conductivity higher than that of the globe is formed on the inner surface of the globe, and the translucent layer is formed. There is disclosed a lamp that is connected to a heat sink through a heat transfer portion made of a heat transfer material having a thermal conductivity equal to or higher than that of the heat transfer.

  Patent Document 2 discloses an illumination device in which a translucent member containing a phosphor is disposed in an opening of a frame surrounding an LED, and a heat conducting member is embedded in the light shielding member to dissipate heat. .

JP 2010-16223 A (published January 21, 2010) JP 2010-141171 A (released on June 24, 2010)

  However, in the lamp disclosed in Patent Document 1, in order to improve the thermal conductivity by forming a translucent layer on the inner surface of the globe, a material having a thermal conductivity comparable to that of metal is used. Although it is necessary to form a thick film, such a material generally has low translucency, and the thick film has a problem that the light transmittance is drastically reduced and the total luminous flux is reduced. Moreover, in the illuminating device shown by patent document 2, even if the heat_generation | fever from a LED element is thermally radiated from a heat conductive member, heat will remain in the globe of an LED bulb.

  Therefore, the present invention has been made in view of the above problems, and does not interfere with the light emitted from the LED element, efficiently releases heat from the LED element, and further improves the light distribution characteristics of the LED bulb. An object of the present invention is to provide a simple lighting device.

  A lighting device according to the present invention includes a light emitting element that emits light, a substrate on which the light emitting element is mounted, a heat sink that carries the substrate and dissipates heat generated from the light emitting element, the light emitting element, the substrate, The illumination device includes a glove that covers the heat radiating plate and transmits light emitted from the light emitting element, and the heat radiating plate is in contact with the inner wall of the globe at least in a region other than the end.

  Moreover, the lighting device according to the present invention is characterized in that the heat dissipation plate has a polyhedral shape, and has one or more flat portions for loading the substrate on a side of the heat dissipation plate facing the globe. To do.

  Moreover, the illuminating device according to the present invention is characterized in that the heat radiating plate has a region other than the planar portion inscribed in the glove via a heat conducting member and bonded thereto.

  Further, the lighting device according to the present invention is characterized in that a pattern for diffusing light is applied to a part or all of the inner wall and / or outer wall of the globe facing the flat portion. .

  Further, in the lighting device according to the present invention, a roughening process for diffusing light is performed on a part or all of the inner wall and / or outer wall of the globe facing the flat surface. Features.

  In the illumination device according to the present invention, the globe is made of a diffusing material that diffuses light.

  An electronic apparatus according to the present invention includes any one of the above illumination devices.

  ADVANTAGE OF THE INVENTION According to this invention, the temperature rise of a light emitting element can be suppressed and the luminous efficiency can be improved by discharging | emitting the heat from an LED element efficiently, without disturbing the light emitted from an LED element. Furthermore, it is possible to realize a high-luminance lighting device that improves the light distribution of the LED bulb.

It is sectional drawing which shows the whole structure of the LED light bulb which concerns on embodiment. It is sectional drawing which shows the structure of the contact part vicinity of the globe of the LED bulb in embodiment, and the polyhedron-shaped heat sink. It is sectional drawing which shows the structure of the contact part vicinity of the globe of the LED bulb in embodiment, and the polyhedron-shaped heat sink. It is sectional drawing which shows the structure of the contact part vicinity of the globe of the LED bulb in embodiment, and the heat sink of a polyhedron shape, and the direction of light. It is a figure which shows the structure of the heat sink of a polyhedron shape in embodiment. It is a figure which shows the shape of the other polyhedral-shaped heat sink in embodiment. It is a figure which shows the shape of the other polyhedral-shaped heat sink in embodiment. It is sectional drawing which shows the whole structure of the LED bulb in embodiment. It is sectional drawing which shows the whole structure of the conventional LED bulb.

  Hereinafter, an illumination device 100 according to an embodiment of the present invention will be described based on FIGS. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts.

<Configuration of lighting device>
FIG. 1 is a cross-sectional view showing the overall configuration of the LED bulb 100. The LED bulb 100 in this embodiment includes a globe 1, an LED package 2, an LED package mounting substrate 3, a heat sink 12, a heat sink 5, an insulating ring 6, a power supply substrate 7, a sealing resin 8, a base 9, a lead wire 10, and a lead wire. 11 and an adhesive 4 that connects the globe 1 and the heat sink 12.

  The globe 1 is formed in a dome shape by translucent PC (polycarbonate). The material of the globe 1 is not limited to this as long as the material has translucency, and for example, a material such as glass or acrylic can be used. The globe 1 is disposed on a heat sink 5 described later, and is fixed by a known method such as an adhesive or a screw.

  2 to 4 show a diffusion pattern 14 applied to the globe 1. Although details will be described later, the shape (diffusion pattern) for diffusing such light is applied to the inner surface side or the outer surface side of the globe 1, and the light emitted from the LED package 2 is diffused. Further, a heat radiating plate 12 described later is attached to the inner surface side of the globe 1 with an adhesive 4.

  Needless to say, the shape of the diffusion pattern 14 applied to the globe 1 is appropriately designed depending on the LED package performance and the distance between the globes. Further, the diffusion pattern 14 may be provided on the entire inner wall and / or outer wall of the globe facing the LED package 2. In addition, in addition to the end surface where the globe 1 is in contact with the heat sink 5, the end portion of the globe 1 in the present application includes the vicinity thereof, for example, a range within about 3 mm from the end surface to the outer wall and the inner wall side. In addition, the edge part of the globe 1 is not limited to this range.

The LED package 2 includes a plurality of LED elements, a mounting substrate on which the LED elements are mounted, and a sealing material that seals the LED elements. The LED element has a sapphire (Al ₂ O ₃ ) substrate, which is an insulating substrate, and a semiconductor light emitting layer made of gallium nitride (GaN) stacked on top, and an electrode layer (ITO layer) formed on the upper surface. is there. The LED element is wire-bonded and mounted on the mounting substrate with a wire. The mounting substrate has wiring, and the LED element is electrically connected to the wiring on the mounting substrate. A sealing material (not shown) made of resin covers a plurality of LED elements, includes a fluorescent paint, converts the color of light emitted from the LED elements into a desired color, and makes the elements difficult to deteriorate. It also has an effect.

  The LED package mounting substrate 3 is a base on which the LED package 2 is mounted. In order to transmit the heat generated from the LED package 2 to the heat sink 12, the material is aluminum (A6063). The material of the LED package mounting substrate 3 is not limited to this, and various materials such as a material having high thermal conductivity, such as a metal such as iron, copper, and aluminum, and alloys thereof can be used. When the LED package 2 has an electrode for surface mounting connected on the back side of the LED package and is solder-connected to the LED package mounting substrate 3, the LED package mounting substrate 3 is patterned with a metal and an insulator. Substrates can be used.

  FIG. 5 is a diagram showing the configuration of the heat sink 12. The heat sink 12 has an area on which the LED package mounting substrate 3 is stacked having a flat part 13, and the flat part 13 is provided in the same number as the LED package, and the area other than the flat part 13 is an area of the globe 1. The structure has a spherical surface that comes into contact with the inner wall. The smaller the area of the plane on which the LED package 2 is mounted, the larger the area in contact with the inner wall of the globe and the greater the effect of transferring heat to the globe 1. The heat transmitted to the globe 1 is radiated from the surface of the globe 1 as it is. Depending on how much the temperature of the LED bulb is lowered, the shape and area of the flat portion 13 are adjusted as shown in FIGS. Moreover, the shape of the heat sink 12 is not limited to these, and can take various forms.

  As another embodiment, FIG. 8 shows a cross-sectional view of an LED bulb when the heat sink 12 of FIG. 6 is used.

  The heat sink 12 is attached to the inner surface side of the globe 1 by an adhesive 4 and is thermally connected. The higher the thermal conductivity of the adhesive 4, the better. Further, the heat sink 12 is thermally connected to the heat sink 5 by screws or an adhesive, whereby the heat generated by the LED package 2 is transmitted to the heat sink 12 via the LED package mounting substrate 3, and the heat Is further transmitted to globe 1 to dissipate heat. As a method of attaching the heat sink 12, various means such as insert molding on the globe 1 can be used.

  The material of the heat sink 12 is aluminum (A6063), and the heat conductivity is as high as 210 W / m · K, so the heat transfer effect is high. Moreover, the material of the heat sink 12 is not limited to this, and various materials such as a material having high thermal conductivity, for example, a metal such as iron, copper, and aluminum, and an alloy thereof can be used. Among them, a material having a thermal conductivity of 100 W / m · K or more is preferable because it easily conducts heat.

  The heat sink 5 is provided with a plurality of heat radiating fins (not shown) on the side surface radially from the center of the heat sink 5 to the outside, and radiates heat generated from the LED package 2 and transmitted through the heat radiating plate 12. To do. The heat sink 5 is fixed to the heat radiating plate 12 by a known method such as an adhesive, a screw, and caulking. In order to efficiently transfer the heat transferred from the LED package 2 through the heat sink 12 to the entire heat sink 5, the material of the heat sink 5 is aluminum (A6063). The material of the heat sink 5 is not limited to this, and various materials such as a material having high thermal conductivity, such as a metal such as iron, copper, and aluminum, and alloys thereof can be used.

  Moreover, since the surface of the heat sink 5 is anodized and the emissivity is higher than that of normal aluminum, heat can be effectively radiated. The surface treatment is not limited to this, and various means for improving the emissivity, such as applying a radiation paint, can be used.

  The insulating ring 6 is a member for insulating the heat sink 5 and the base 9 so as not to be in electrical contact, and the material is PBT (polybutylene terephthalate). The material of the insulating ring 6 is not limited to this, and a highly insulating material such as PC or PPS (polyphenylene sulfide) having high thermal conductivity while maintaining insulation can be used. The insulating ring 6 is fixed to the heat sink 5 by a known method such as an adhesive or a screw.

  The power supply board 7 includes a plurality of electronic components (not shown) (for example, a rectifier circuit that rectifies AC power supplied from a commercial power source into DC power, a voltage adjustment circuit that adjusts the voltage value of the DC power rectified by the rectifier circuit, etc. ) Is a circuit board mounted on the substrate for causing the LED package 2 to emit light. The power supply substrate 7 is fixed to the insulating ring 6 by a known method such as locking means or fixing means.

  The sealing resin 8 is filled in the insulating ring 6 and the base 9 and covers the power supply substrate 7. The material of the sealing resin 8 is a resin having high insulating properties and high thermal conductivity, and has a function of conducting heat generated from the power supply substrate 7 to the insulating ring 6 and the base 9.

  The base 9 is, for example, an Edison type E26 base, and has a metallic shell portion formed in a cylindrical shape with a thread. The base 9 has a metal eyelet part at the top of one end side of the shell part via an insulating part (not shown), and the other end side is attached to the insulating ring 6.

  The conducting wire 10 is a wiring for electrically connecting the power supply substrate 7 and the base 9. The conducting wire 10 is connected to the inner surface of the eyelet portion of the power supply substrate 7 and the base 9, and the not-shown conductive wire is connected to the inner surface of the shell portion of the power supply substrate 7 and the base 9, In contact with the power supply board 7 to transmit the power supplied from the lamp.

<Heat dissipation path>
Next, the heat dissipation circuit in this embodiment will be described. The heat generated by the electronic components on the power supply board 7 is mainly transmitted to the base 9 through the power supply board 7 and the sealing resin 8 or through the conductive wire 10 and from there to a lamp (not shown) to be external to the LED bulb. Heat is released by radiation, convection, and heat conduction. A part of the heat generated by the electronic components on the power supply board 7 is transmitted to the insulating ring 6 through the power supply board 7 and the sealing resin 8, and is radiated to the outside of the LED bulb by radiation and convection. Further, a part of the heat is transferred to the heat sink 5 and radiated to the outside of the LED bulb by radiation and convection.

  The heat generated by the LED package 2 is transmitted to the heat sink 5 through the heat radiating plate 12 and is radiated to the outside of the LED bulb 100 by radiation and convection. When there is no heat sink 12 like a conventional LED bulb, the globe with a low thermal conductivity of 1 W / m · K or less is only a few millimeters from the part in contact with the base for mounting the LED package mounting board. Heat is not transmitted. For this reason, almost no heat is transmitted to the entire globe, and the heat radiation from the globe is very small. Since the globe occupies about 1/3 of the surface area of the LED bulb, the heat generation of the LED package 2 is transmitted to the heat sink 5 through the heat radiating plate 12 by adopting the configuration of this embodiment, so that a high heat dissipation effect can be obtained. it can.

  In this embodiment, since the heat sink 12 is in thermal contact with the inner surface side of the globe 1, the heat generated by the LED package 2 is transmitted to the heat sink 12 via the LED package mounting substrate 3, and the heat is further added to the adhesive. 4 is transmitted to the inner surface side of the globe 1. The heat transmitted to the inner surface side of the globe 1 is transmitted to the outer surface side of the globe 1. The thermal conductivity of the globe 1 is as low as 1 W / m · K or less, but since the thickness is about 1 mm, heat is transmitted to the outer surface side of the globe 1. Heat is transmitted from the portion where the heat radiating plate 12 and the globe 1 are in thermal contact to the entire globe 1 and the temperature of the globe 1 rises. Although the heat conductivity of the globe 1 is low, since the surface of the globe 1 is in contact with the globe 1 except for the plane on which the LED package 2 is mounted on the heat sink 12, the temperature of the globe 1 at the contact point is sufficiently increased, The amount of heat released from 1 by radiation and convection is greatly increased. Thereby, the heat generated from the LED package 2 can be efficiently released from the globe 1 and the temperature rise of the LED package 2 is suppressed, so that the light emission efficiency of the LED package 2 is improved.

<Exit path>
Next, the light emission path in the present embodiment will be described. Light emitted from the LED package 2 is emitted to the outside of the LED bulb 100 through the inside of the globe 1 mainly through the air in the globe 1. A part of the light emitted from the LED package 2 hits the surface of the heat sink 12 through the air in the globe 1, is reflected, passes through the inside of the globe 12, and is emitted to the outside of the LED bulb.

  When the globe used in the current LED bulb and the heat sink 12 of the present invention are brought into contact with each other, the contact portion prevents light from being transmitted to the outside and transmits light within the globe surface. The uneven light emission occurs at the portion where the light is transmitted and the portion where the light is not transmitted. However, in the globe 1 of the present invention, a diffusion pattern 14 as shown in FIGS. 2 to 4 is provided in the vicinity of contact with the polyhedral heat sink 12.

  When the light emitted from the light emitting element enters the globe 1 having the diffusion pattern 14 inside as shown in FIG. 2, the light is diffused in all directions by the uneven shape formed on the inner wall surface of the globe. Uneven light emission can be reduced.

  In addition, when the light emitted from the light emitting element is incident on the globe 1 having the diffusion pattern 14 on the outside as shown in FIG. 3, the light is transmitted in all directions due to the uneven shape formed on the outer wall surface of the globe. It diffuses and light emission unevenness can be reduced.

  Further, if a prism-shaped diffusion pattern 14 as shown in FIG. 4 is applied, the light is refracted to the contact surface side between the globe 1 and the heat sink 12 as shown by the dotted arrows in the figure, thereby reducing uneven emission. can do. The diffusion pattern 14 is not limited to the one described above, and the shape, position, size, and the like may be set as appropriate depending on the light diffusion range, light intensity, and the like.

  Further, in the case of the conventional LED bulb as shown in FIG. 9, the light emitted from the LED package spreads from the base on which the LED package mounting substrate is attached to the globe side, whereas the LED bulb of the present invention. In this case, since the LED package 2 is three-dimensionally arranged, light is emitted also to the base 9 side, and the light distribution is improved.

  As described above, the polyhedral heat sink 12 is attached to the inner surface side of the globe 1 with the diffusion pattern 14 so that the heat is also radiated from the globe 1, thereby efficiently releasing the heat generated from the LED package 2. Therefore, the luminous efficiency of the LED package 2 is improved. In addition, by applying the diffusion pattern 14 to the globe 1, unevenness of light emission can be reduced. Furthermore, by mounting the LED package 2 three-dimensionally, the light distribution characteristics are improved as compared with existing LED bulbs.

  The lighting device of the present invention has a wide range of applications that can be applied not only to LED bulbs using LEDs but also to all lighting devices.

DESCRIPTION OF SYMBOLS 1,91 Globe 2,92 LED package 3,93 LED package mounting board 4 Adhesive 5,95 Heat sink 6,96 Insulation ring 7,97 Power supply board 8,98 Sealing resin 9,99 Base 10 Lead wire 11 Lead wire 12 Heat dissipation Plate 13 Plane portion 14 Diffusion pattern 94 Stand for mounting LED package mounting board 100, 100 'LED bulb 900 Conventional LED bulb

Claims (7)

A light emitting element;
A substrate on which the light emitting element is mounted;
A heat sink on which the substrate is loaded;
An illumination device comprising a globe that covers the light emitting element, the substrate, and the heat radiating plate and transmits light emitted from the light emitting element,
The heat radiating plate is in contact with the inner wall of the globe at least in a region other than the end portion.   2. The lighting device according to claim 1, wherein the heat radiating plate has a polyhedral shape, and has at least one flat portion for loading the substrate on a side of the heat radiating plate facing the globe.   3. The lighting device according to claim 1, wherein a region other than the flat portion of the heat radiating plate is inscribed and bonded to the globe via a heat conductive member.   The lighting device according to claim 1, wherein a pattern for diffusing light is applied to a part or all of the inner wall and / or outer wall of the globe facing the flat portion. .   The roughening process for diffusing light is given to the one part or all area | region of the said globe inner wall and / or outer wall which face the said plane part, The Claim 1 to 3 characterized by the above-mentioned. Lighting equipment.   The lighting device according to claim 1, wherein the globe is made of a diffusion material that diffuses light.   An electronic apparatus comprising the lighting device according to claim 1.