JP2010080458A - Lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device capable of obtaining similar light even from the other surface even when having semiconductor light emitting elements arranged on one surface. <P>SOLUTION: The lighting device includes the translucent substrate 2 having a first surface and a second surface, a plurality of semiconductor light emitting elements 7 arranged on the first surface and a phosphor layer 18 provided on the first surface so as to cover the plurality of semiconductor light emitting elements, and a light diffusion layer 50b provided on the other surface. <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.

  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 also from both directions. In such a case, it is preferable that the metal substrate on which the plurality of chips are disposed has translucency.

An LED lamp configured to emit light in one direction is described in Japanese Utility Model Publication No. 6-21258. This LED lamp has a light diffusing sheet, and light from a plurality of light emitting elements arranged in parallel at a predetermined interval on a flat substrate surface is diffused by the light diffusing sheet and partially strengthened. There is no problem.
JP 2004-140185 A (paragraphs 0017-0021, FIG. 2) Japanese Utility Model Publication No.6-212258 (Example column, FIG. 4 etc.)

The illumination devices described in Patent Documents 1 and 2 do not emit light from both directions including not only from one direction but also from the back side. Moreover, it is difficult to emit light uniformly from both directions only by changing the substrate on which the plurality of chips are arranged in the illumination devices of Patent Documents 1 and 2 to a light-transmitting substrate such as a glass substrate.
An object of the present invention is to provide an illuminating device capable of obtaining equivalent light from the other surface even when the semiconductor light emitting element is disposed on one surface of the substrate.

  The invention according to claim 1 is a translucent substrate having a first surface and a second surface; a plurality of semiconductor light emitting elements disposed on the first surface; and the plurality of semiconductor light emitting elements And a phosphor layer provided on the first surface; and a light diffusion layer provided on the second surface.

  In the invention of claim 1, examples of the light-transmitting substrate include transparent glass, a transparent acrylic resin, and a light-transmitting 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. The phosphor layer emits yellow light by the excitation of the blue light, and the yellow light and the blue light are added to emit white light. As a result, white light is emitted from each of the first surface side and the second surface side, but as described above, the intensity of the blue light emitted from the second surface side is stronger, as described above. Accordingly, blue light becomes conspicuous, and the portion of the semiconductor light emitting element becomes relatively bright. Therefore, the light diffusion layer provided on the second surface diffuses the blue light and suppresses the bright part from being noticeable. The blue light emitted from the first surface side is diffused to some extent by the phosphor layer.

  According to a second aspect of the present invention, there is provided the lighting device according to the first aspect, wherein the second translucent material has substantially the same material and thickness as the translucent substrate and is provided on the phosphor layer side. And a second light diffusion layer provided on the second light-transmitting substrate.

  As described above, the phosphor layer emits yellow light by the excitation of the blue light, and the yellow light and the blue light are added to emit white light. The white light is radiated to the outside through the second light transmissive substrate and the second light diffusion layer on the first surface side, and the light transmissive substrate and the second light side on the second surface side. Since the light is emitted to the outside through the light diffusion layer, it is emitted through a similar path. For this reason, white light emitted from both sides tends to have the same quality and quantity.

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 white light can be obtained from the other surface.
According to the second aspect of the present invention, the white light emitted from both sides can have the same quality and quantity.

  An 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 light diffusion layer 50b provided on the second surface side of the substrate 2, a plurality of semiconductor light emitting elements such as LED chips (hereinafter abbreviated as LEDs) 7, bonding wires 11 and 12, 1 frame 14, second frame 16, phosphor layer 18, second translucent substrate 30 provided on phosphor layer 18, and light provided on second translucent substrate 30 A diffusion layer 50a is provided.

  The planar view shape of the substrate 2 is, for example, a quadrangle as shown in FIG. The substrate 2 has electrical insulation and translucency, and 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. This board | substrate part 3 has electrical insulation and translucency, for example, is made from the transparent glass plate. Specifically, the substrate portion 3 is made of transparent quartz glass having a thickness of 0.5 mm to 1.5 mm so as to withstand the curing of the phosphor layer 18 at 100 ° C. to 150 ° C.

  The second light-transmitting substrate 30 has substantially the same material (quartz glass) and the same thickness as the light-transmitting substrate 2, and is provided on the phosphor layer 18 side. The layer 50 a is provided on the second light transmitting substrate 30. The phosphor layer 18 emits yellow light by excitation of the blue light of the LED 7, and the yellow light and the blue light are added to emit white light. The white light is radiated to the outside through the second light-transmitting substrate 30 and the second light diffusion layer 50a on the first surface 3a side, and is transmitted on the second surface 3b side. Since it is emitted outside through the optical substrate 3 and the light diffusion layer 50b, it is emitted through the same path. For this reason, the white light emitted from both sides can be of the same quality and quantity. Further, the afterimage (crushing feeling) of the blue light emitted from the LED 7 is alleviated. The light diffusing layer and the second light diffusing layer may be provided by frosting the surface of quartz glass.

  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 phosphor layer 18 is filled in the first frame 14 in a substantially full state, seals all the LEDs 7 and bonding wires 11, 12, etc. accommodated in the first frame 14, The sealing material 40 protects these from moisture, outside air, and the like, thereby preventing the life of the lighting device 1 from being reduced. The phosphor layer 18 is made of a translucent material such as a translucent resin, specifically a thermosetting silicone resin. The phosphor layer 18 is cured by being injected in a predetermined amount into the first frame 14 in an uncured liquid state and then heated in a heating furnace.

  In the 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.

  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. 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 a lighting device 1 in which a plurality of heat exhaust members 4 made of tungsten wire 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.

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.

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 portion of heat exhausting member, 7 ... LED (semiconductor light emitting element), 11 ... bonding wire, 18 ... phosphor layer, 30 ... translucent substrate, 40 ... sealing material, 50a ... second light diffusion layer, 50b ... light diffusion layer.

Claims (2)

A translucent substrate having a first surface and a second surface;
A plurality of semiconductor light emitting elements disposed on the first surface;
A phosphor layer provided on a first surface so as to cover the plurality of semiconductor light emitting elements;
A light diffusion layer provided on the second surface;
An illumination device comprising: A second translucent substrate having substantially the same material and thickness as the translucent substrate and provided on the phosphor layer side;
A second light diffusion layer provided on the second light transmissive substrate;
The lighting device according to claim 1, comprising:

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