JP2011096876A - Light emitting device, and lighting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device suppressing blackening of a reflecting surface in a mounting pad having a surface formed as a reflecting surface and capable of suppressing deterioration in light extraction efficiency, and to provide a lighting apparatus using the light emitting device. <P>SOLUTION: The light emitting device 1 includes: a substrate 10 having an insulating layer on a surface thereof; mounting pads 15a provided on the insulating layer of the substrate 10, having a surface formed as a reflecting surface, and arranged adjacent with each other so that the insulating layer is interposed therebetween; a light emitting element 11 mounted on at least one or more mounting pads 15a; and a sealing resin layer 12 covering the light emitting element 11 and arranged in a region on each mounting pad 15a and in an inside of the periphery of each mounting pad 15a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light emitting device and a lighting device using a light emitting element such as an LED.

  Recently, a lighting device has been developed in which a plurality of light emitting elements such as LEDs are arranged on a substrate as a light source to obtain a predetermined amount of light. This lighting device is used as, for example, a so-called direct mounting type base lighting that is directly attached to a ceiling surface or the like, and a plurality of LEDs are fixed to a substrate formed of a ceramic material with an epoxy resin or the like. The light emitting devices are arranged side by side (see, for example, Patent Document 1).

  On the other hand, in order to improve the extraction efficiency of light emitted from the light emitting element, a light emitting device has been developed in which a mounting pad on which the light emitting element is mounted is provided on a substrate and a reflective layer is formed on the surface of the mounting pad.

JP 2009-54989 A

  However, in a light emitting device in which a reflective layer is formed on the surface of the mounting pad, a phenomenon occurs in which the reflective layer is blackened by the action of an insulating layer on the substrate surface, a phosphor layer covering the light emitting element, or the like. When the reflective layer of the mounting pad is blackened, there is a problem that the reflected light of the light traveling from the light emitting element toward the substrate surface is reduced, and the light extraction efficiency is lowered.

  The present invention has been made in view of such problems, and in a mounting pad whose surface is formed as a reflective surface, the light emitting device capable of suppressing the blackening of the reflective surface and suppressing the decrease in light extraction efficiency and the light emission thereof It aims at providing the illuminating device using an apparatus.

  The light emitting device according to claim 1 is provided with a substrate having an insulating layer on a surface thereof; provided on the insulating layer of the substrate, the surface is formed as a reflecting surface, and is adjacent to each other so that the insulating layer is interposed therebetween. A light-emitting element mounted on at least one or more mounting pads; and covering the light-emitting element and disposed in an area on the mounting pad and inside the outer periphery of the mounting pad. And a sealing resin layer provided.

  In the present invention and the following inventions, the technical meaning and interpretation of terms are as follows unless otherwise specified. For example, it is preferable to use a substrate formed of a material such as glass epoxy resin, but a substrate having an insulating layer formed on the surface using a material having good thermal conductivity such as aluminum is used for the core. Can do. A light emitting element is a solid light emitting element such as an LED. Moreover, there is no restriction | limiting in particular in the mounting number of a light emitting element.

  The mounting pad is preferably used as, for example, a wiring pattern, but is not necessarily used as a wiring pattern. That is, as long as the reflective surface is formed, it is not always necessary to be electrically connected. Further, the mounting pad may be polygonal or circular, and the shape and dimensions are not particularly limited.

“A light emitting element mounted on at least one mounting pad” means that the light emitting element is mounted on the mounting pad, but allows the presence of a mounting pad on which the light emitting element is not mounted. For example, a wiring means such as a lead wire may be connected to the mounting pad and the light emitting element may not be mounted. In addition, a plurality of light emitting elements can be mounted on one mounting pad.
The sealing resin layer means, for example, a phosphor layer, but does not necessarily contain a phosphor. Any resin layer that covers and seals the light-emitting element may be used.

  Further, “the sealing resin layer disposed in the region on the mounting pad and inside the outer periphery of the mounting pad” is formed so that the sealing resin layer does not protrude from the region on the mounting pad. Means that.

  According to a second aspect of the present invention, there is provided an illumination device comprising: a device main body; and the light emitting device according to the first aspect disposed in the device main body. The lighting device includes a light bulb shaped light source, a lighting fixture used indoors or outdoors, a display device, and the like.

According to the first aspect of the present invention, it is possible to provide a light emitting device that can suppress the blackening of the reflection surface of the mounting pad and suppress the decrease in the light extraction efficiency.
According to invention of Claim 2, the illuminating device which has the effect of invention of Claim 1 can be provided.

It is a perspective view which shows the light-emitting device of the 1st Embodiment of this invention. It is sectional drawing which follows the AA line in FIG. It is sectional drawing which expands and shows the same. It is a top view which shows the wiring pattern in a board | substrate. It is a top view which shows the state which mounted the light emitting element in the wiring pattern of the board | substrate in FIG. 4, and apply | coated the phosphor layer. It is a top view which expands and shows the principal part of FIG. It is a side view which shows an illuminating device. It is a top view which shows the state seen from the same downward direction. It is a perspective view which shows the illuminating device of the 2nd Embodiment of this invention. It is a top view equivalent to FIG. 6 which shows a comparative example. It is sectional drawing equivalent to FIG. 3 which shows the comparative example.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 6 show the light emitting device 1, and FIGS. 7 and 8 show an illumination device 20 using the light emitting device 1. In addition, the same code | symbol is attached | subjected to the same part in each figure, and the overlapping description is abbreviate | omitted.

  As shown in FIGS. 1 and 2, the light emitting device 1 includes a substrate 10, a plurality of light emitting elements 11, a phosphor layer 12 that covers each light emitting element 11, and a protective cover 13 that covers the phosphor layer 12. I have.

  The substrate 10 is formed in a substantially square shape. The substrate 10 is an insulating material, and is formed of a glass epoxy resin or the like which is a synthetic resin material having an insulating layer on the surface and having a low thermal conductivity. In addition, although it is preferable to use what the board | substrate 10 formed with the material with low heat conductivity, this invention is a board | substrate which formed the insulating layer on the surface using materials with favorable heat conductivity, such as aluminum, for the core. May be applied.

  On the surface side of the substrate 10, a wiring pattern 15 to be described in detail later is formed. As shown in FIG. 1, the wiring pattern 15 includes a substantially rectangular mounting pad 15a in which each light emitting element 11 is disposed, a power supply conductor 15b having a predetermined pattern for electrically connecting the mounting pads 15a, and a power supply terminal. 15c. The mounting pads 15a are arranged in a matrix on the surface of the substrate 10 and formed in a plurality of rows, for example, 6 rows.

  As representatively shown in FIG. 3, the wiring pattern 15 has a three-layer structure, and a copper pattern is provided on the surface of the substrate 10 as a first layer 151 by etching. On the copper pattern layer, nickel (Ni) is electroplated as the second layer 152, and silver (Ag) is electroplated on the third layer 153. The third layer 153 of the wiring pattern 15, that is, the surface layer, is all subjected to silver (Ag) plating, and the total light reflectance is as high as 90%. Therefore, the surface of the mounting pad 15a is formed as a reflecting surface by silver (Ag) plating.

  The plurality of light emitting elements 11 are LED bare chips. For example, an LED bare chip that emits blue light in order to cause white light to be emitted from the light emitting unit is used. The bare chip of this LED is bonded onto the mounting pad 15a using a silicone resin-based insulating adhesive 16. The plurality of light emitting elements 11 form a plurality of light emitting element rows and are arranged in a matrix, and specifically, a total of 48 pieces of 8 × 6 rows are mounted.

  An LED bare chip is, for example, an InGaN-based element, in which a light-emitting layer is stacked on a light-transmitting sapphire element substrate, and the light-emitting layer includes an n-type nitride semiconductor layer, an InGaN light-emitting layer, and a p-type nitride layer. A physical semiconductor layer is sequentially stacked. And the electrode for sending an electric current through a light emitting layer was formed with the p-type electrode pad on the p-type nitride semiconductor layer, and the n-type electrode pad on the n-type nitride semiconductor layer. It consists of a negative electrode. These electrodes are electrically connected on the wiring pattern 15 by bonding wires 17. The bonding wires 17 are made of gold (Au) fine wires, and are connected via bumps mainly composed of gold (Au) in order to improve mounting strength and reduce damage to bare LED chips.

  The phosphor layer 12 is made of a translucent synthetic resin, for example, a transparent silicone resin, and contains an appropriate amount of phosphor. The phosphor layer 12 has a mountain shape on the side surface and forms a dome shape, and individually covers each light emitting element 11 to form a sealing resin layer. The phosphor is excited by light emitted from the light emitting element 11 and emits light of a color different from the color of light emitted from the light emitting element 11. In the present embodiment in which the light emitting element 11 emits blue light, a yellow phosphor that emits yellow light having a complementary color relationship with blue light is used for the phosphor so that white light can be emitted. Has been. And the fluorescent substance layer 12 is provided corresponding to each light emitting element 11 in an uncured state, and then cured by heating or standing for a predetermined time.

  The protective cover 13 covers the entire area on the surface side of the substrate 10 including the phosphor layer 12. The protective cover 13 has translucency, is formed of a transparent acrylic resin or polycarbonate resin, has a storage recess 13a of the substrate 10 on the back side, and is molded into a substantially square dish shape. In the drawing, an air layer is formed on the upper surface side of the storage recess 13a, which is formed of a conical recess so as to face each light emitting element 11, that is, each phosphor layer 12, and has a circular opening 19a below. Means 19 are formed. The air layer forming means may be formed as a member separate from the protective cover 13 and this member may be provided on the protective cover 13.

  Furthermore, a flange 13e is formed on the side peripheral surface of the protective cover 13 so as to protrude to the outer periphery. The flange 13e functions as an attachment portion when the light emitting device 1 is attached to a portion to be attached, that is, a screw or the like as a fixing means to the main body or base of the lighting device 20.

  Furthermore, a heat insulating layer 18 is formed on the back side of the substrate 10. The heat insulating layer 18 is configured to form an air layer between the back side of the substrate 10 and the attached portion. That is, a predetermined interval is provided between the back side of the substrate 10 and the attached portion. Specifically, a predetermined interval is provided between the back surface side of the substrate 10 and the attached portion by the depth dimension of the storage recess 13a and the mounting screw 13c for fixing the substrate 10 at a predetermined position. It is supposed to be formed. Therefore, in this embodiment, the storage recess 13a and the mounting screw 13c constitute a heat insulation layer forming means. Note that the heat insulating layer 18 may be configured by arranging a heat insulating material in a portion of the air layer, for example, without depending on the air layer.

  The substrate 10 and the protective cover 13 are fixed by a transparent silicone adhesive 13b interposed between the surface side of the substrate 10 and the inner wall of the storage recess 13a of the protective cover 13. The adhesive 13b is interposed over almost the entire area between the surface side of the substrate 10 and the region of the protective cover 13 excluding the air layer forming means 19. Therefore, the substrate 10 is securely attached to the protective cover 13 by the adhesive 13b and the attachment screw 13c. Thus, when the substrate 10 is attached to the protective cover 13, a conical air layer A is formed between the air layer forming means 19 facing each light emitting element 11 and the surface side of the substrate 10. become.

  Next, in the light emitting device 1 configured as described above, an arrangement relationship between the mounting pad 15a, the light emitting element 11, and the phosphor layer 12 covering the light emitting element 11 will be described with reference to FIGS.

  As shown in FIG. 4, a wiring pattern 15 is formed on the surface side of the substrate 10. The wiring pattern 15 includes a mounting pad 15a, a power supply conductor 15b, and a power supply terminal 15c. The mounting pad 15a basically has a quadrangular shape, and on one side, a narrow feeding conductor 15b1 for bonding wire connection extends in a direction orthogonal to the side (in the horizontal direction in the drawing). The power supply conductor 15b1 is positioned so as to approach the adjacent mounting pad 15a (left mounting pad 15a).

  These mounting pads 15a are formed on the substrate 10 so as to be arranged in a matrix adjacent to each other so that an insulating layer on the surface of the substrate 10 is interposed. As a whole, the mounting pads 15a are vertically symmetrical about the central portion of the substrate 10. It is arranged. That is, the upper three rows and the lower three rows are arranged symmetrically. In addition, the rows are electrically connected to each other by a power supply conductor 15b. Note that the corners of adjacent mounting pads 15a are connected to each other by a power supply conductor 15b, but a through hole 15d is formed at an intermediate portion thereof. The power supply conductor 15b is cut, and the adjacent mounting pads 15a are electrically disconnected. The portion of the power supply conductor 15b is used to apply a potential when the mounting pads 15a are subjected to electrolytic plating.

  The power supply terminal 15c is a power supply terminal on the positive electrode and negative electrode sides, and is connected to the power supply conductors 15b on the left and right ends. A lead wire is connected to the power supply terminal 15c by solder or the like, and power is supplied from a power supply circuit (not shown).

  As shown in FIG. 5, a plurality of light emitting elements 11 are mounted on the mounting pad 15 a of the wiring pattern 15 formed in this way, and sealed so as to be covered with the phosphor layer 12. . Among the plurality of light emitting element rows, the plus side electrode and the minus side electrode of the light emitting element 11 in each light emitting element row are sequentially connected to the mounting pad 15a and the power supply conductor 15b1 of the adjacent mounting pad 15a by the bonding wire 17, respectively. ing. Therefore, two series circuits to which the plurality of light emitting elements 11 are connected are connected in parallel with the feeding terminal 15c on the positive and negative sides as a connection point. That is, in the drawing, the upper three light emitting element rows are connected in series, the lower three light emitting element rows are connected in series, and these are connected in parallel to the power supply. .

  The phosphor layer 12 is applied so as to cover each light emitting element 11 individually. In this application, it is applied in an uncured state, and then cured by heating or leaving it for a predetermined time. Specifically, as representatively shown in FIG. 6, the phosphor layer 12 has a formation range a (schematically shown in a circle), that is, a coating range within the formation region A of the mounting pad 15a. It is applied to the inside of the formation area A of the mounting pad 15a so as to fit. This can be achieved by adjusting the application position, the application amount, the viscosity, and the like of the phosphor layer 12.

  Here, for example, as shown in FIGS. 10 and 11, when the formation range a of the phosphor layer 12 ′ does not fall within the formation area A of the mounting pad 15 a and is applied so as to protrude, the surface of the mounting pad 15 a It turned out that the phenomenon that the reflective layer (Ag) of the film becomes black occurs and the progress thereof is fast. In particular, blackening seems to start from the edge of the mounting pad 15a. This blackening phenomenon is caused when the insulating layer or the phosphor layer 12 ′ on the surface of the substrate 10 is heated by the heat generated from the light emitting element 11 during lighting, and the hydrogen halide is removed from the residue and the insulating layer when the substrate 10 is cleaned. It is considered that a small amount of gas component such as this is generated, which acts on the reflective layer on the surface of the mounting pad 15a by the radiated light of the light emitting element 11, and the reflective layer is photoreacted and blackened.

  When the phosphor layer 12 ′ is applied so as to protrude from the mounting pad 15 a as in this example, the reflection layer is blackened by the radiated light of the light-emitting element 11 that is multiply reflected inside the phosphor layer 12 ′. Is presumed to progress.

  Therefore, in the present embodiment, the phosphor layer 12 is arranged in the region of the mounting pad 15a and inside the outer periphery of the mounting pad 15a, and thus is caused by the insulating layer on the surface of the substrate 10. Therefore, it is possible to reduce the effect of the above, and to suppress blackening of the reflective layer.

  Further, in the form shown in FIGS. 10 and 11, there is a step corresponding to the thickness dimension of the mounting pad 15 a between the surface of the mounting pad 15 a and the surface of the substrate 10. The shape is not stable, and a concave portion is partially formed (see FIG. 11), so that the rate of deformation increases. For this reason, the possibility of uneven color and uneven brightness of the light emitted from the light emitting element 11 increases.

  In this embodiment, since the phosphor layer 12 is formed in the region of the mounting pad 15a as described above, the stability of the dome-shaped shape of the phosphor layer 12 can be ensured and emitted from the light emitting element 11. It becomes possible to suppress light color unevenness and brightness unevenness.

  Next, with reference to FIG.7 and FIG.8, the illuminating device 20 using the above-mentioned light-emitting device 1 is demonstrated. The lighting device 20 is used by being attached to a ceiling surface C, and includes a base body 21 and a plurality of light emitting devices 1 disposed on the base body 21. The base body 21 is made of aluminum and has a substantially rectangular shape. The light emitting device 1 is fixed to the base body 21 by screws or the like, while the base body 21 is attached to the ceiling surface C by fixing means such as bolts. The light emitting device 1 is connected to a power supply unit including a power supply circuit (not shown). Note that the number of the light emitting devices 1 can be appropriately selected and arranged.

  The operation of the light emitting device 1 having the above-described configuration will be described. When energized by the power supply circuit, the light emitting elements 11 emit light all at once, and the light emitting device 1 is used as a planar light source that emits white light. During this light emission, the mounting pad 15a functions as a heat spreader that diffuses the heat generated by each light emitting element 11. Further, of the light emitted from the light emitting element 11 during the light emission of the light emitting device 1, the light directed toward the substrate 10 is reflected mainly in the light utilization direction by the reflective layer of the mounting pad 15a. Therefore, the light extraction efficiency can be improved.

  Air layer forming means 19 is provided opposite to each light emitting element 11, thereby forming an air layer A, so that the light emitted from each light emitting element 11 is transmitted between the air layer A and the protective cover 13. It is diffused at the interface and irradiated to the outside of the protective cover 13. Therefore, the brightness of light emitted from the protective cover 13 of the light emitting device 1 is made uniform, and uneven brightness can be suppressed.

  During the light emission of each light emitting element 11, heat is generated from the light emitting element 11, but this heat is mainly conducted to the light emitting element 11, the mounting pad 15 a, the substrate 10, and the protective cover 13 to be radiated. That is, the heat from the light emitting element 11 is conducted to the front side and radiated. Therefore, heat conduction to the back surface side of the substrate 10 is suppressed, and heat conducted to the ceiling surface C and the like is reduced.

  In addition, in the present embodiment, the substrate 10 is formed of a glass epoxy resin or the like having low thermal conductivity, and a heat insulating layer 18 is formed on the back side of the substrate 10. Therefore, heat conduction to the back side of the light emitting device 1 is suppressed, and heat conduction to the front side can be promoted.

Furthermore, since the protective cover 13 is provided as the light emitting device 1, it is not necessary to provide a front cover or the like as the lighting device 20, and the configuration can be simplified. In addition, dust does not enter between the substrate 10 and the protective cover 13, and it is difficult to get dirty, and a waterproof function can be realized.
Furthermore, since the phosphor layer 12 is applied so as to cover each light emitting element 11 individually, the amount of the phosphor can be reduced, which is advantageous in terms of cost.

  As described above, according to the present embodiment, it is possible to provide a light-emitting device that can suppress blackening of the reflective layer of the mounting pad 15a and suppress a decrease in light extraction efficiency. Further, the stability of the shape of the phosphor layer 12 can be ensured, and unevenness in color and luminance of light emitted from the light emitting element 11 can be suppressed.

Next, a second embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part which is the same as that of 1st Embodiment, or an equivalent, and the overlapping description is abbreviate | omitted. In the present embodiment, a direct ceiling-mounted illumination device 30 that is installed and used on the ceiling surface C is shown. The illuminating device 30 includes a main body case 31 having a substantially rectangular parallelepiped shape, and a plurality of the light emitting devices 1 are linearly arranged in the main body case 31. The power supply unit is built in the main body case 31. Note that a front cover or the like as the lighting device 30 is not provided in the lower opening of the main body case 31.
As described above, according to the present embodiment, it is possible to provide the illumination device 30 that has the same effect as the light emitting device 1 of the first embodiment.

  The present invention is not limited to the configuration of each of the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, the mounting pad is preferably used as a wiring pattern, but is not necessarily used as a wiring pattern. That is, as long as the reflective surface is formed, it is not always necessary to be electrically connected. In addition, the mounting pad may have a quadrilateral shape, a polygonal shape, a circular shape, or the like, and the shape is not particularly limited.

  For example, the light emitting unit may be configured to emit red light, green light, and blue light directly from the light emitting element without using a phosphor. The lighting device can be applied to a light bulb-shaped light source, a lighting fixture used indoors or outdoors, a display device, and the like.

DESCRIPTION OF SYMBOLS 1 ... Light-emitting device, 10 ... Board | substrate, 11 ... Light emitting element (LED chip),
12 ... sealing resin layer (phosphor layer), 13 ... protective cover,
15 ... wiring pattern, 15a ... mounting pad,
17 ... bonding wire, 18 ... heat insulation layer, 19 ... air layer forming means,
20, 30 ... Lighting device, A ... Air layer

Claims (2)

A substrate having an insulating layer on the surface;
A mounting pad provided on the insulating layer of the substrate and having a surface formed as a reflective surface and disposed adjacent to each other so that the insulating layer is interposed;
A light emitting device mounted on at least one mounting pad;
A sealing resin layer that covers the light emitting element and is disposed in the region on the mounting pad and inside the outer periphery of the mounting pad;
A light-emitting device comprising: The device body;
The light-emitting device according to claim 1 disposed in the device body;
An illumination device comprising:

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