JP5067631B2 - Lighting device - Google Patents

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.

For example, a planar light emitting device configured by arranging a plurality of LED (light emitting diode) chips and the like in a planar shape is described in Japanese Patent Application Laid-Open No. 2004-140185. In this light emitting device, a plurality of chips are arranged on a metal substrate and configured to emit light in one direction. However, in consideration of application to a lighting fixture or the like, it may be desirable that light is emitted not only from one direction but from both directions. In such a case, it is preferable that the metal substrate on which the plurality of chips are disposed has translucency.
JP 2004-140185 A (paragraphs 0017-0021, FIG. 2)

The light emitting device described in Patent Document 1 does not emit light from both directions including not only from one direction but also from the back side. Moreover, light cannot be radiated | emitted equally from both directions only by changing the metal substrate used for the light-emitting device of patent document 1 to translucent board | substrates, such as a glass substrate.
An object of the present invention is to provide an illuminating device that can obtain equivalent light from the other surface even if the semiconductor light emitting element is disposed on one surface of the substrate.

  The invention of claim 1 includes a substrate having a first surface, a second surface parallel to the first surface, and a substrate portion having electrical insulation and translucency having a peripheral surface extending over both surfaces; and an element electrode. A plurality of semiconductor light emitting elements disposed on the first surface; a first phosphor layer provided to cover the plurality of semiconductor light emitting elements; and a thickness of the first phosphor layer And a second phosphor layer provided on the second surface so as to be thicker.

  In the first aspect of the present invention, examples of the electrically insulating / translucent insulating material for the substrate include transparent glass, transparent acrylic resin, and translucent ceramic. The plurality of semiconductor light emitting elements emit blue light, for example, but the intensity of light emitted on the second surface side is higher than the intensity of light emitted on the first surface side. Further, for example, the first and second phosphor layers emit yellow light by the excitation of the blue light, and the yellow light and the blue light are added to emit white light. Since the intensity of the blue light incident on the second phosphor layer is different and the intensity of the second phosphor layer is stronger, the thickness of the second phosphor layer is increased correspondingly to reduce the blue light. It is something to be made. As a result, the white light emitted from the first surface side and the second surface side of the substrate is substantially equivalent in quality and quantity.

  According to a second aspect of the present invention, in the lighting device according to the first aspect, the substrate includes a heat radiating portion formed of a material having a higher thermal conductivity than the substrate portion, and the heat radiating portion is the second surface. Or it is the some heat exhaust member arrange | positioned inside the said board | substrate part, It is characterized by the above-mentioned.

  When a substrate provided with a heat exhausting member is used inside the substrate section or on the surface where the semiconductor light emitting element is not mounted, heat conducted from each semiconductor light emitting element to the substrate is exhausted in a state where the plurality of semiconductor light emitting elements emit light. It can guide | induct with a thermal member and can discharge | emit it to the exterior of a board | substrate from the edge part of these exhaust heat members. Thereby, as the temperature rise of the substrate having the substrate portion can be suppressed, the heat radiation from the semiconductor light emitting element to the substrate is maintained, and the temperature rise of each semiconductor light emitting element can be suppressed.

  According to the first aspect of the present invention, even if the semiconductor light emitting element is disposed on one surface of the substrate, the same light can be obtained from the other surface.

  According to invention of Claim 2, the heat | fever conducted from each semiconductor light-emitting device to a board | substrate can be guide | induced with a heat exhaust member, and it can discharge | emit to the exterior of a board | substrate from the edge part of these heat exhaust members, and improves luminous efficiency. Can do.

  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, bonding wires 11 and 12, a first frame body 14, a second frame body 16, and a first frame. The phosphor layer 18 and the second phosphor layer 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 as heat radiating portions, 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. This board | substrate part 3 has electrical insulation and translucency, for example, is made from the transparent glass plate. Specifically, a thickness of 0.5 mm to 1.5 mm is provided so as to withstand the first phosphor layer 18 and the second phosphor layer 20 as the phosphor layers at 100 ° C. to 150 ° C. The substrate part 3 is made of transparent quartz glass. The second surface of the quartz glass substrate portion 3 may be subjected to a frost treatment to provide a light diffusion portion (light diffusion layer) or may be subjected to prism cut. As a result, the afterimage (crushing feeling) of the blue light emitted from the LED 7 is alleviated.

  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 phosphor layer 18 is filled in the first frame body 14 in a substantially full state, and seals all the LEDs 7 and bonding wires 11, 12, etc. accommodated in the first frame body 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 phosphor layer 18 is made of a translucent material such as a translucent resin, specifically a thermosetting silicone resin. The first phosphor layer 18 is cured by being injected into the first frame 14 in a non-cured liquid state and then heated in a heating furnace.

  In the first phosphor layer 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 translucent substrate 30 is made of quartz glass and is provided so as to cover the first phosphor layer 18. Further, on the surface side (outside) of the quartz glass 30, a light diffusing portion (light diffusing layer) may be provided by performing a frost treatment, or a prism cut may be performed. Then, the afterimage (crushing feeling) of the blue light emitted from the LED 7 is alleviated, and moisture or the like is prevented from adhering to the LED 7 and the first phosphor layer 18.

  The second phosphor layer 20 is filled in the second frame 16 in a substantially full state. The second phosphor layer 20 is made of a translucent material, for example, a translucent resin, specifically, a thermosetting silicone resin. The second phosphor layer 20 is cured by being heated in a heating furnace after being injected into the second frame 16 by a predetermined amount in an uncured liquid state.

  Also in the second phosphor layer 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 phosphor layer 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. The thickness of the second phosphor layer 20 is provided on the second surface 3 b so as to be thicker than the thickness of the first phosphor layer 18. The reason for this is that although the LED 7 emits blue light, the intensity emitted on the second surface 3b side is stronger than the intensity emitted on the first surface 3a side. The phosphor layer 20 is thickened to reduce the blue light. As a result, the white light radiated from the first surface 3a side and the second surface 3b side of the substrate unit 3 has substantially the same quality and quantity. Further, quartz glass which is a translucent substrate 30 may be provided so as to cover the second phosphor layer 20, and in this case, moisture or the like adheres to the second phosphor layer 20. It can be prevented. In addition, it is preferable that the refractive indexes of the substrate unit 3 and the first and second phosphor layers are approximate because light loss at each interface can be suppressed.

  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 in FIG. 2 from each LED 7 and the yellow light emitted from the phosphor excited in the first phosphor layer 18 by a part thereof are mixed. 2 is emitted in the vertical direction in FIG.

At the same time, the blue light emitted from each LED 7 in the downward direction in FIG. White light generated by mixing yellow light emitted from the phosphor excited in the layer 20 is emitted downward 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 rated current (20 mA) is applied to the lighting device 1 in which a plurality of heat exhaust members 4 made of tungsten wires are embedded in a quartz glass substrate portion 3 in a grid pattern, and is turned on. 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.

  Next, FIGS. 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 phosphor layer 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.

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 ... Peripheral surface of a board | substrate part, 4 ... Heat exhaust member (radiation part) ) 4a... End portion of exhaust heat member, 7... LED (semiconductor light emitting element), 11... Bonding wire, 18... First phosphor layer, 20.

Claims (2)

A substrate comprising a first surface, a second surface parallel to the surface, and a substrate portion having electrical insulation and translucency having a peripheral surface extending over both surfaces;
A plurality of semiconductor light emitting devices having device electrodes and disposed on the first surface;
A first phosphor layer provided to cover the plurality of semiconductor light emitting elements;
A second phosphor layer provided on the second surface so as to be thicker than a thickness of the first phosphor layer;
An illumination device comprising:   The substrate includes a heat radiating portion formed of a material having a higher thermal conductivity than the substrate portion, and the heat radiating portion is a plurality of heat exhaust members disposed inside the second surface or the substrate portion. The lighting device according to claim 1, wherein the lighting device is provided.

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