JP2009231148A - Illuminating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminating device can restrain degradation of light-emission efficiency of semiconductor light-emitting devices by improvement of heat dissipation performance of the device, going through an electric insulation substrate. <P>SOLUTION: The illuminating device 1 is provided with an electric insulation substrate 2, a plurality of LEDs (semiconductor light-emitting devices) 7 and a bonding wire (an electric conductor) 11. The substrate 2 is provided with a substrate part 3 and a plurality of exhaust heat members 4. The substrate part 3 includes a first face 3a, a second face 3b parallel with that 3a and a peripheral face 3c going over both faces 3a and 3b. Each exhaust heat member 4 is formed by a material with higher thermal conductivity than that of the substrate part 3. Those exhaust heat members 4 are arranged inside the substrate part 3, and their end parts 4a are made protruded against the peripheral face 3c. The LEDs 7 contain element electrodes. Each LED 7 is arranged on a first face 3a of the substrate 2. The bonding wire 11 is connected to the element electrodes to electrically connect the LEDs 7 with each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lighting device having a semiconductor light emitting element such as a plurality of LED (light emitting diode) chips and used for, for example, a lighting fixture or a display.

Conventionally, a plurality of LED bare chips are arranged in a matrix form vertically and horizontally on a metal-based printed circuit board, and these LED bare chips are connected in series by the wiring pattern of the board, so that each LED bare chip emits light as a planar light source. A lighting device to be used is known (for example, see Patent Document 1). The light emitted from the LED bare chip in this illuminating device is emitted light from the semiconductor light emitting layer, but in the illuminating device of Patent Document 1, the light irradiation direction is only on one side of the metal base printed board.
Japanese Patent Laid-Open No. 2004-19335 (paragraphs 0012-0038 and FIGS. 1 to 10)

  The configuration in which the substrate is a metal base printed board as in the lighting device of Patent Document 1 is preferable in that the heat generated by the LED bare chip mounted on the board is easily radiated to the metal base of the metal base printed board. However, the illumination device using the metal-based printed board cannot fully trust the electrical insulation between the printed board and the LED bare chip. For example, there is a risk that the electrical insulation between the LED bare chip and the metal base of the metal base printed board may not be ensured when the sealing member sealing the LED bare chip is peeled off and moisture enters and abnormal current flows. Conceivable.

  Such a problem can be improved by forming the entire printed circuit board with an insulating material. However, the thermal conductivity of electrically insulating glass or synthetic resin material is as low as about 1 W / m · K. For this reason, when the input supplied to the LED bare chip is large, or when the LED bare chip is arranged at high density, the heat generated by the LED bare chip through the insulating substrate cannot be exhausted sufficiently and quickly to the outside. The temperature of the bare chip tends to rise excessively. When the temperature of the LED bare chip rises, the light emission efficiency of the LED bare chip decreases, so a technique for suppressing this is desired.

  The objective of this invention is providing the illuminating device which can improve the thermal radiation performance of the semiconductor light-emitting element which passes through an electrically insulating board | substrate, and can suppress the fall of the luminous efficiency of this element.

  The invention of claim 1 is formed of an electrically insulating substrate portion having a first surface, a second surface parallel to the surface, and a peripheral surface over both surfaces, and a material having a higher thermal conductivity than the substrate portion. And a substrate having a plurality of heat removal members disposed inside the second surface or the substrate portion and having an end projecting with respect to the peripheral surface; And a plurality of semiconductor light emitting elements disposed on the first surface; and an electrical conductor connected to the element electrode to electrically connect the semiconductor light emitting elements.

  In the invention of claim 1, the substrate portion can be made of an opaque or translucent electrically insulating material. Examples of the opaque electrical insulating material include a synthetic resin or ceramic that does not have translucency, and examples of the translucent insulating material include transparent glass, a transparent acrylic resin, or a translucent ceramic. . In the first aspect of the present invention, a metal can be suitably used for the heat removal member. For example, a metal wire, a metal foil, a metal plate, or the like having a rod shape or a belt shape can be employed as the heat removal member.

  In the invention of claim 1, as the semiconductor light emitting element, at least one kind of LED chip emitting single colors of red, green and blue can be used, and an organic EL element or the like can also be used. In the first aspect of the invention, the electric conductor is a bonding wire connected to an element electrode of a semiconductor light emitting element, or a case where the semiconductor light emitting element is disposed by flip chip mounting (flip chip bonding) on a substrate. Denotes a wiring pattern or the like formed on a substrate and connected to an element electrode of a semiconductor light emitting element.

  According to the first aspect of the present invention, since the substrate provided with the heat exhausting member is employed inside the electrically insulating substrate portion or on the surface where the semiconductor light emitting element is not mounted, a plurality of semiconductors electrically connected through the electric conductor In a state where the light emitting element emits light, heat conducted from each semiconductor light emitting element to the substrate can be guided by the heat exhausting member, and discharged from the end of the heat exhausting member to the outside of the substrate. Thereby, as the temperature increase of the substrate having the electrically insulating substrate portion can be suppressed, the heat radiation from the semiconductor light emitting element to the substrate is maintained, and the temperature increase of each semiconductor light emitting element can be suppressed.

  According to a second aspect of the present invention, in the first aspect of the invention, the substrate portion is made of a light-transmitting electrical insulating material, and the plurality of heat exhaust members are arranged in a lattice shape. It is said.

  In the second aspect of the present invention, in the form in which the exhaust heat members are "arranged in a grid", a plurality of exhaust heat members such as the metal wire are combined and arranged in a grid pattern (mesh). Or a vertical grid, that is, a form in which a plurality of heat removal members are arranged in parallel with the left and right sides extending in the vertical direction of a square substrate, or a horizontal grid, that is, a side of a square substrate. It includes a form in which a plurality of heat exhaust members are arranged in parallel with the upper and lower sides extending in the direction. The plurality of exhaust heat members arranged in this way are preferably provided at equal intervals.

  In the invention of claim 2, since the substrate portion is translucent and the plurality of heat exhaust members are arranged in a lattice shape, the semiconductor light emitting device is arranged from the first surface side of the substrate on which the semiconductor light emitting device is arranged. The light emitted by the semiconductor light emitting element can be transmitted between adjacent heat exhaust members so that the light emitted from the semiconductor light emitting element can be transmitted from the second surface side where each semiconductor light emitting element is not mounted. Can be put out. That is, light can be extracted from both sides of the substrate.

  Furthermore, a third aspect of the invention is characterized in that, in the second aspect of the invention, the semiconductor light emitting element is disposed between the adjacent heat exhaust members.

  In this invention of Claim 3, since the light taken out from the second surface side where each semiconductor light emitting element is not mounted is not blocked by the lattice-shaped heat exhaust member, the light is efficiently transmitted from the second surface side. Can be taken out.

  According to the illuminating device of the first and second aspects of the invention, the heat radiation performance of the semiconductor light emitting element that passes through the electrically insulating substrate can be improved, and the decrease in the luminous efficiency of this element can be suppressed.

  According to the illuminating device of the invention of claim 2, in the invention of claim 1, light can be further taken out from both surfaces of the substrate.

  According to the lighting device of the invention of claim 3, in the invention of claim 2, it is possible to further improve the efficiency of extracting light from the second surface side of the substrate.

  A first embodiment of the present invention will be described with reference to FIGS.

  Reference numeral 1 in FIGS. 1 and 2 denotes an illumination device that forms an LED package. The lighting device 1 includes a substrate 2, a plurality of semiconductor light emitting elements such as LED chips (hereinafter abbreviated as LEDs) 7, metal conductors such as bonding wires 11 and 12, a first frame body 14, a second frame body 16, The first sealing member 18 and the second sealing member 20 are provided.

  The planar view shape of the substrate 2 is, for example, a quadrangle as shown in FIG. The substrate 2 includes a substrate portion 3, a plurality of heat exhaust members 4, and a pair of electrode patterns 5.

  As shown in FIG. 2, the substrate part 3 has a first surface 3a, a second surface 3b parallel to the first surface 3a, and a peripheral surface 3c extending over both surfaces. The substrate portion 3 has electrical insulation, and is preferably made of a light-transmissive electrical insulation material, for example, a transparent glass plate. Specifically, the substrate portion is made of transparent quartz glass having a thickness of 0.5 mm to 1.5 mm so that the first sealing member 18 and the second sealing member 20 can be cured at 100 ° C. to 150 ° C. 3 is made.

  The plurality of heat exhaust members 4 are made of metal wires having a circular or square cross section, and are embedded in the substrate portion 3 at regular intervals in the vertical and horizontal directions as shown in FIG. It is arranged. Therefore, as shown in FIG. 1, the grid of grids formed by the exhaust heat members 4 arranged vertically and horizontally, in other words, a space between the adjacent heat exhaust members 4 forms a square. The end 4a of each heat exhaust member 4 protrudes with respect to the peripheral surface 3c.

  In order to prevent the heat removal member 4 and the substrate portion 3 from being peeled off, the linear expansion coefficients of the heat removal member 4 and the substrate portion 3 are substantially the same. Specifically, a tungsten wire whose surface is oxidized is adopted as the exhaust heat member 4.

  As will be described later, the plurality of heat exhaust members 4 disposed in the lateral (left-right) direction in FIG. As shown in FIG. 2, the substrate portion 3 is buried at a position approximately half the thickness direction. At the same time, the plurality of heat exhausting members 4 disposed so as to extend in the vertical (vertical) direction in FIG. 1 with respect to the substrate unit 3 are the heat exhausting members 4 extending in the lateral direction as shown in FIG. It is buried between the second surface 3b.

  Accordingly, the distance between the first surface 3 a and each heat exhaust member 4 is larger than the distance between the second surface 3 b and the heat exhaust member 4. Accordingly, the first surface 3a on which the LED 7 is mounted becomes flat by suppressing the portion of the first surface 3a corresponding to the portion directly above the heat exhaust member 4 from swelling due to the heat exhaust member 4. It is like that.

  The pair of electrode patterns 5 are respectively provided at the left and right end portions of the first surface 3 a of the substrate portion 3. These electrode patterns 5 are made of copper foil or the like, and are formed in a comb shape as shown in FIG. One electrode pattern 5 is for the positive electrode, and the other electrode pattern 5 is for the negative electrode. These electrode patterns 5 are connected to electric wires (not shown) for guiding a direct current supplied from a power supply circuit (not shown).

  For each LED 7, for example, a double wire type using a nitride semiconductor is employed. These LEDs 7 are formed by providing a semiconductor light emitting layer on one surface of a translucent element substrate made of sapphire or the like. The semiconductor light emitting layer emits blue light, for example. The LED 7 emitting blue light has a pair of element electrodes for positive electrode and negative electrode (not shown) on the semiconductor light emitting layer side.

  As shown in FIG. 1, the LEDs 7 are two-dimensionally arranged in rows and columns on the first surface 3 a of the substrate unit 3. Each LED 7 is mounted on the substrate portion 3 by using a light-transmitting die bond material (not shown) on the other surface of the element substrate that is parallel to one surface on which the semiconductor light emitting layer is stacked and on which the semiconductor light emitting layer is not stacked. 1 is bonded to the surface 3a.

  As described above, these LEDs 7 are arranged so as to face the center portion of the grid of the grid as shown in FIG. 1 in the positional relationship with the heat exhaust members 4 arranged in a grid pattern. It is installed. The distance L between each heat exhaust member 4 and the LED 7 (represented by the distance between the lower heat exhaust member 4 and the LED 7 in FIG. 2) is preferably 0.2 mm or more. By doing in this way, even if the first surface 3a is swollen due to the heat exhausting member 4 embedded in the substrate section 3, the LED 7 can be mounted at a position deviated from the swollenness. Thereby, since mounted LED7 does not tilt according to the said swelling, the desired light distribution can be obtained.

  The bonding wires 11 and 12 are made of fine metal wires such as Au wires. The LEDs 7 arranged between the electrode patterns 5 and arranged in the horizontal direction of the substrate 2 are electrically connected in series with bonding wires 11 connected to the element electrodes by wire bonding. .

  Thus, the element electrode of the LED 7 positioned at one end of the LED array formed by the plurality of LEDs 7 connected in series by the bonding wire 11 and the comb-tooth portion of the one electrode pattern 5 are electrically connected by the bonding wire 12. Yes. Similarly, the element electrode of the LED 7 positioned at the other end of each LED row and the comb tooth portion of the other electrode pattern 5 are also electrically connected by the bonding wire 12.

  As shown in FIG. 1, the first frame body 14 has a square frame shape that is large enough to accommodate all LEDs 7 with an electrically insulating material such as a synthetic resin, and is formed on the first surface 3 a of the substrate portion 3. It is mounted using an adhesive. The first frame body 14 is bonded to the first surface 3 a across the comb tooth portions of the pair of electrode patterns 5.

  The second frame 16 is also made of an electrically insulating material such as a synthetic resin. The second frame body 16 is the same size as the first frame body 14, but its thickness is thinner than that of the first frame body 14. The second frame 16 is attached to the second surface 3b of the substrate unit 3 using an adhesive.

  The first sealing member 18 is filled in the first frame 14 in a substantially full state, and seals all the LEDs 7 and the bonding wires 11, 12, etc. accommodated in the first frame 14. Thus, these are protected from moisture, outside air, and the like to prevent a decrease in the lifetime of the lighting device 1. The first sealing member 18 is made of a translucent material, for example, a translucent resin, specifically, a thermosetting silicone resin. The first sealing member 18 is cured by being heated in a heating furnace after being injected into the first frame body 14 in an uncured liquid state.

  In the first sealing member 18, phosphors (not shown) are preferably mixed in a uniformly dispersed state. The phosphor is excited by a part of the light emitted from each LED 7 and emits light of a color different from the color of the light emitted from the LED 7, and thereby the color of the illumination light emitted from the illumination device 1. Is used to define In the present embodiment, in order to change the color of the illumination light emitted from the illumination device 1 to white light, a phosphor that emits yellow light that is complementary to the blue light emitted by each LED 7 is used. Has been.

  The second sealing member 20 is filled in the second frame 16 in a substantially full state. The second sealing member 20 is made of a translucent material, for example, a translucent resin, specifically, a thermosetting silicone resin. The second sealing member 20 is cured by being heated in a heating furnace after being injected into the second frame 16 in a non-cured liquid state.

  Also in the second sealing member 20, phosphors (not shown) are preferably mixed in a uniformly dispersed state. In order to change the color of the illumination light emitted from the illumination device 1 to white light in the same manner as the phosphor mixed in the first sealing member 18, the phosphor is made of blue light emitted from each LED 7. Thus, a phosphor that emits yellow light having a complementary color relationship is used.

  1 and 2 indicates a metal heat dissipating member formed in a frame shape larger than the substrate 2. The inner peripheral side portion of the heat radiating member 22 is bonded to the second surface 3 b, and the outer peripheral side portion of the heat radiating member 22 protrudes from the peripheral surface of the substrate 2. The projecting portions are connected in a state where the end portions 4a of the heat exhausting member 4 are in contact with each other. The lighting device 1 can be attached and supported via the heat dissipation member 22.

  By supplying power to each LED row of the illumination device 1 having the above-described configuration through the electrode pattern 5, a plurality of LEDs 7 included in these LED rows emit light all at once. Therefore, the blue light emitted upward from FIG. 2 from each LED 7 and the yellow light emitted from the phosphor excited in the first sealing member 18 by a part thereof are mixed. 2 is emitted upward in FIG. 2.

  At the same time, the blue light emitted downward from FIG. 2 from each LED 7 passes through the transparent die-bonding material and the transparent substrate portion 3, so that the second sealing is performed by the blue light and a part thereof. The white light produced | generated by mixing with the yellow light radiated | emitted from the fluorescent substance excited in the member 20 is radiate | emitted below in FIG.

  As described above, since the lighting device 1 can extract white light from both surfaces of the substrate 2, it can be suitably used for lighting applications that require such double-sided light emission.

  In this illuminating device 1, the LEDs 7 are disposed so as to face the eyes of the grid pattern formed by the plurality of heat exhaust members 4. Not. Therefore, light can be efficiently taken out from the second surface 3b side of the substrate 2 without being obstructed by the heat exhausting member 4.

  During the above illumination, each LED 7 generates heat. The heat generated by these LEDs 7 is conducted to the electrically insulating substrate 3, and the heat exhaust member 4 is embedded in the substrate 3 in a lattice shape. Therefore, the heat conducted from each LED 7 to the substrate 2 can be guided by the lattice-shaped heat exhaust member 4, and can be quickly discharged from the end 4 a of the heat exhaust member 4 to the heat radiating member 22 outside the substrate 2. Thereby, as the temperature rise of the substrate 2 having the electrically insulating substrate portion 3 can be suppressed, the heat dissipation from the LED 7 to the substrate 2 is maintained, and the temperature rise of each LED 7 can be suppressed. Therefore, a decrease in light emission efficiency of each LED 7 is suppressed.

  Incidentally, as described above, the present embodiment in which the lighting device 1 in which a plurality of heat exhaust members 4 made of tungsten wires are embedded in a lattice pattern in a quartz glass substrate portion 3 is turned on by flowing a rated current (20 mA). Then, it was confirmed that the substrate temperature can be reduced by 10 ° C. to 20 ° C. as compared with the configuration without the exhaust heat member.

  Moreover, since each LED 7 is arrange | positioned facing the center part of the eye of the grid of the plurality of heat exhausting members 4 as described above, the vertical and horizontal positions located so as to surround one LED 7 are arranged. The distance between the exhaust heat member 4 and the LED 7 that it surrounds is equal. Therefore, the dispersion | variation in the heat dissipation from each LED7 to the exhaust heat member 4 is suppressed. As a result, variations in the temperature of each LED 7 are suppressed, and as a result, variations in the light emission luminance of each LED 7 can also be suppressed.

  3 and 4 show a second embodiment of the present invention. Since the second embodiment has the same configuration as that of the first embodiment except for the matters described below, the same components are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

  In the second embodiment, the plurality of heat removal members 4 combined in a grid pattern are not embedded in the board part 3, but the surface of the board part 3 opposite to the LED mounting surface (first mounting surface), that is, The heat exhausting member 4 is disposed on the second surface 3b of the substrate unit 3 by adhesion. Therefore, a portion between both end portions 4 a of the heat exhausting member 4, that is, an intermediate portion located in the second frame body 16 is filled with the second sealing member 20.

  Further, a groove 22 a is formed in the heat radiating member 22 for accommodating the end 4 a of the heat exhausting member 4 protruding from the peripheral surface 3 c of the substrate portion 3. The end 4a is fixed in contact with the bottom surface of the groove 22a.

  Furthermore, in 2nd Embodiment, each LED7 is arrange | positioned by the 1st surface 3a of the board | substrate 2 facing the heat exhausting member 4 extended in an up-down direction in FIG. Instead of this, the arrangement of each LED 7 can be arranged so as to oppose the intersecting portion of the vertical and horizontal heat exhaust members 4, and between the adjacent heat exhaust members 4 as in the first embodiment. It is also possible to arrange them facing each other.

  The configuration of the second embodiment is the same as that of the first embodiment except for the matters described above. Therefore, 2nd Embodiment can solve the subject of this invention for the reason already demonstrated in 1st Embodiment.

  Moreover, in the second embodiment, the flatness of the first surface 3a is easily ensured by disposing the heat exhausting members 4 on the second surface 3b in a lattice pattern. Further, since each LED 7 is disposed so as to face the heat exhausting member 4, the light extraction property from the second surface 3 b side is lowered, but the LED 7 efficiently passes through the substrate portion 3 to the heat exhausting member 4. It is preferable in that heat can be taken out and discharged.

  In addition, this invention is not restrict | limited to the said each embodiment. For example, when the substrate unit 3 is a lighting device that emits light on one side using a non-translucent insulating material, the second frame body 16 and the second sealing member 20 may be omitted. In addition, in the case of performing double-sided emission by irradiating using the emission color of the LED 7 as it is, the first sealing member 18 does not have to be mixed with the phosphor, and the second frame 16 and the second frame 16. The sealing member 20 can be omitted.

The front view shown in the state which partly cut away the illuminating device which concerns on 1st Embodiment of this invention. Sectional drawing of the illuminating device shown along the arrow F2-F2 line | wire in FIG. The front view shown in the state which partly cut away the illuminating device which concerns on 2nd Embodiment of this invention. Sectional drawing of the illuminating device shown along the arrow F4-F4 line | wire in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Illuminating device, 2 ... Board | substrate, 3 ... Board | substrate part, 3a ... 1st surface of a board | substrate part, 3b ... 2nd surface of a board | substrate part, 3c ... Perimeter surface of a board | substrate part, 4 ... Waste heat member, 4a ... End of heat exhausting member, 7 ... LED (semiconductor light emitting element), 11 ... bonding wire (electrical conductor)

Claims (3)

An electrically insulating substrate portion having a first surface, a second surface parallel to the surface, and a peripheral surface over both surfaces, and a material having a higher thermal conductivity than the substrate portion, and the peripheral surface A substrate provided with a plurality of heat removal members disposed on the second surface or the substrate portion with an end portion protruding from the second surface or the substrate portion;
A plurality of semiconductor light emitting devices having device electrodes and disposed on the first surface;
An electrical conductor connected to the element electrode and electrically connecting the semiconductor light emitting elements;
An illumination device comprising:   The lighting device according to claim 1, wherein the substrate portion is made of a light-transmitting electrical insulating material, and the plurality of heat exhausting members are arranged in a lattice shape.   The lighting device according to claim 2, wherein the semiconductor light emitting element is disposed between the adjacent heat exhaust members.

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