JP2012015226A - Light emitting device and illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable light-emitting device and an illumination device capable of preventing high cost by using gold (Au) for a power feeding terminal layer that is a part of a wiring pattern.SOLUTION: A light emitting device 1 comprises: a substrate 2 that has an insulation property at least on the surface of the substrate 2; a wiring pattern 3 that is formed on the surface side of the substrate 2, and that includes a power feeding conductive layer 31 and a power feeding terminal layer 32 made up of gold or alloy mainly including gold, and that is electrically connected to a cross-laminated part of the power feeding conductive layer 31 and the power feeding terminal layer 32; and a light emitting element 4 that is electrically connected to the wiring pattern 3 and mounted on the substrate 2.

Description

  Embodiments described herein relate generally to a light-emitting device and a lighting device that use light-emitting elements such as LEDs.

  Recently, LEDs have been used as light sources for lighting devices. In this light source, a wiring pattern such as a copper foil is formed on a substrate to mount a large number of LED bare chips, and each LED chip is connected with bonding wires and electrically connected to the wiring pattern to constitute a light emitting device. Is. In such a light emitting device, generally, a power supply connector is soldered to a power supply terminal layer of a wiring pattern that is electrically connected to an LED so that power is supplied.

  On the other hand, higher output of the light emitting device has been demanded, and in order to realize this higher output, it is necessary to increase the current supplied to the LED. However, if the supplied current is large, the temperature of the LED rises and the device operates at a high temperature. Accordingly, the temperature of the substrate also rises accordingly, and the thermal expansion of the substrate is caused by the heat cycle of turning on / off the LED. , The difference in shrinkage increases. For this reason, stress is applied to the solder portion of the power supply connector, cracking may occur, and reliability may be reduced.

  Therefore, a method without using solder is performed by connecting a so-called contact pressure type power supply connector to the power supply terminal layer. In this case, the contact member of the power supply connector comes into contact with the power supply terminal layer by the elastic contact pressure. Therefore, in order to maintain the reliability of the contact function of this contact portion, it is conceivable that the entire surface of the wiring pattern including the power supply terminal layer is plated with gold (Au) having excellent conductivity and corrosion resistance.

Japanese Patent No. 3998794 (paragraphs [0169] to [0171], FIG. 14))

  However, gold (Au) is expensive as a material, and using gold (Au) on the entire surface of the wiring pattern causes high costs.

  In view of the above, an object of the present invention is to provide a light emitting device and a lighting device with high reliability by suppressing the high cost by using gold (Au) for a power supply terminal layer which is a part of a wiring pattern.

  The light emitting device of the present invention includes a substrate having at least an insulating surface. A wiring pattern having a feed conductor layer and a feed terminal layer is formed on the surface side of the substrate. The feed terminal layer is made of gold or an alloy mainly composed of gold, and a part of the feed terminal layer and the feed conductor layer are laminated and electrically connected. The light emitting element is electrically connected to the wiring pattern and mounted on the substrate.

  ADVANTAGE OF THE INVENTION According to this invention, high cost can be suppressed and a reliable light-emitting device and illuminating device can be provided.

1 is a perspective view showing a light emitting device according to a first embodiment of the present invention. It is a top view which shows the pattern of the electric power feeding terminal layer and electric power feeding conductor layer in the board | substrate of the light-emitting device. FIG. 3 is a schematic cross-sectional view taken along line XX in FIG. 2. It is a top view shown in the state where a part of the light emitting device was cut away. It is a perspective view which shows the attachment member of the light-emitting device. It is a top view which shows the state which attached the light-emitting device to the attachment member. FIG. 7 is a cross-sectional view taken along line XX in FIG. 6. It is a front view which shows the electrical connection means of the light-emitting device. FIG. 4 is a schematic cross-sectional view corresponding to FIG. 3, showing a light emitting device according to a second embodiment (Example 1) of the present invention. It is typical sectional drawing which shows the same (Example 2). It is typical sectional drawing which shows the same (Example 3).

  Hereinafter, a light emitting device according to a first embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the same part in each figure, and the overlapping description is abbreviate | omitted.

  As representatively shown in FIGS. 1 and 4, the light-emitting device 1 includes a substrate 2, a wiring pattern 3 formed on the surface side of the substrate 2, and a plurality of light-emitting elements mounted on the surface side of the substrate 2. An element 4 is provided.

  The substrate 2 has insulating properties and is formed from a ceramic material such as white aluminum oxide or aluminum nitride. The board | substrate 2 is formed in the substantially square shape, and each corner | angular part has comprised R shape.

  As shown in FIG. 2, a wiring pattern 3 is formed on the surface of the substrate 2, and the wiring pattern 3 includes a power supply conductor layer 31 and a power supply terminal layer 32. The power supply conductor layer 31 includes a positive electrode side power supply conductor layer 31a and a negative electrode side power supply conductor layer 31b. The power supply terminal layer 32 includes a positive electrode side power supply terminal layer 32a and a negative electrode side power supply terminal layer 32b. Yes.

  The positive electrode side power supply conductor layer 31a and the negative electrode side power supply conductor layer 31b are formed in pairs in parallel with a predetermined interval in the vertical direction in the figure. The positive electrode side power supply terminal layer 32a and the negative electrode side power supply terminal layer 32b extend from the middle part of the positive electrode side power supply conductor layer 31a and the negative electrode side power supply conductor layer 31b, respectively, in a substantially T shape toward the outside in a direction orthogonal thereto. It is formed out. Further, the positive electrode side power supply terminal layer 32a and the negative electrode side power supply terminal layer 32b are arranged at 180 ° point symmetrical positions.

  As shown in FIG. 3, a power supply conductor layer 31 and a power supply terminal layer 32 are formed on the substrate 2. The feed terminal layer 32 is made of gold (Au) or an alloy mainly composed of gold (Au), and the feed conductor layer 31 is made of silver (Ag). Further, the surface of the power supply conductor layer 31 is covered with a protective layer 33 such as a glass paste. The protective layer 33 mainly has a function of preventing silver (Ag) of the power supply conductor layer 31 from being sulfided in the air.

  A power supply terminal layer 32 is formed on the substrate 2, and a power supply conductor layer 31 is laminated on a part of the end portion side from above. The power feeding terminal layer 32 and the power feeding conductor layer 31 are electrically connected to each other by the multilayer portion D of the power feeding terminal layer 32 and the power feeding conductor layer 31.

  Each thickness dimension is formed such that the power supply conductor layer 31 has silver (Ag) of 10 μm and the power supply terminal layer 32 has gold (Au) of 0.1 μm to 10 μm, preferably 0.5 μm to 2 μm.

  The feed conductor layer 31 and the feed terminal layer 32 are formed by screen printing. First, the feed terminal layer 32 is printed on the substrate 2, and then the feed conductor layer 31 is printed. Moreover, the protective layer 33 is printed on it and formed by baking. In addition, you may make it perform a baking process for every printing process.

  By forming the power supply conductor layer 31 and the power supply terminal layer 32 by screen printing, formation thereof is cheaper and easier than forming by plating. Also, since gold (Au) is excellent in conductivity and corrosion resistance, it is effective that the power supply terminal layer 32 is formed of gold (Au).

  In addition, the mutual lamination | stacking part of the electric power feeding conductor layer 31 and the electric power feeding terminal layer 32, ie, the multilayer part D, has gold (Au) of the electric power feeding terminal layer 32 on the lower side with respect to silver (Ag) of the electric power feeding conductor layer 31. Preferably there is. In the opposite case, a phenomenon occurs in which the gold (Au) of the power supply terminal layer 32 is easily separated from the silver (Ag) of the power supply conductor layer 31 in the multilayer portion D.

In addition, the area of the multilayer portion D is preferably set to 0.05 mm ² or more. When the thickness is less than 0.05 mm ² , since the lamination area is small, the silver (Ag) of the feeding conductor layer 31 is easily peeled off in the multilayer portion D. Furthermore, in the multi-layer part D, the electric resistance becomes large and tends to generate heat. In the present embodiment, the area of the multilayer portion D is set to 0.5 mm ² .

A plurality of light emitting elements 4 are mounted on the surface of the substrate 2. The light emitting element 4 is made of a bare LED chip. 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.
As shown in FIGS. 1 and 4, the plurality of light emitting elements 4 are arranged in a matrix to form a plurality of columns, for example, six light emitting element columns.

  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. The physical semiconductor layers are sequentially stacked to form a substantially rectangular parallelepiped shape. An electrode for passing a current through the light emitting layer is provided on the upper surface side, and a positive electrode formed by a p-type electrode pad on the p-type nitride semiconductor layer and an n-type nitride semiconductor layer. The negative electrode is formed of an n-type electrode pad. These electrodes are electrically connected by a bonding wire 41. The bonding wire 41 is made of a fine gold (Au) wire, and is connected via bumps mainly composed of gold (Au) in order to improve mounting strength and reduce damage to the bare chip of the LED.

  Specifically, in each light emitting element row, electrodes of different polarities of the light emitting elements 4 adjacent to each other in the extending direction, that is, the positive side of one light emitting element 4 among the adjacent light emitting elements 4. The electrode and the negative electrode of the other light emitting element 4 among the adjacent light emitting elements 4 are sequentially connected by a bonding wire 41. Thus, the plurality of light emitting elements 4 constituting each light emitting element array are electrically connected in series. Therefore, the plurality of light emitting elements 4 emit light simultaneously in the energized state.

  Furthermore, in each light emitting element row, a specific light emitting element, that is, the electrode of the light emitting element 4a arranged at the end of the row is connected to the positive electrode side power supply conductor layer 31a or the negative electrode side power supply conductor layer 31b by a bonding wire 41. ing. Accordingly, the respective light emitting element arrays are electrically provided in parallel, and are fed with power from the power supply terminal layer 32 through the positive electrode side power supply conductor layer 31a and the negative electrode side power supply conductor layer 31b. Therefore, even if any one of the light emitting element rows cannot emit light due to bonding failure or the like, light emission of the entire light emitting device 1 does not stop.

  A frame member 21 is provided on the surface of the substrate 2. The frame member 21 is applied in a substantially rectangular shape, and each light emitting element 4 is disposed inside the frame member 21 surrounded by the inner peripheral surface. That is, the mounting area of the light emitting element 4 is surrounded by the frame member 21.

  Inside the frame member 21, a sealing member 22 is filled and provided on the substrate 2. The sealing member 22 is made of a translucent synthetic resin, for example, a transparent silicone resin, and seals the mounting region of the light emitting element 4.

  The sealing member 22 contains an appropriate amount of phosphor. The phosphor is excited by the light emitted from the light emitting element 4 and emits light of a color different from the color of the light emitted from the light emitting element 4. In the present embodiment in which the light emitting element 4 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. The sealing member 22 is provided by being cured by heating after being injected into the frame member 21 in a predetermined amount in an uncured state.

  The board | substrate 2 comprised as mentioned above is attached to the attachment member 5 shown in FIG. The attachment member 5 is made of an aluminum material or the like having good heat conduction, and is formed with a concave portion 51 in which the substrate 2 is placed at the center portion in a square shape. Further, a screw through hole used for fixing the mounting member 5 to the main body of the lighting device or the like is formed at the corner of the mounting member 5. The attachment member 5 may be a so-called heat sink, apparatus main body, case or cover. In short, it means a member to which the substrate 2 is attached.

  As shown in FIGS. 6 and 7, the substrate 2 is positioned and arranged with the concave portion 51 of the attachment member 5 as a guide, and is attached so that the back surface side is in close contact with the bottom surface of the concave portion 51. That is, the electrical connection means 6 is applied with an elastic contact pressure in a direction from the surface side of the substrate 2 toward the mounting member 5 side.

  As shown in FIG. 8 with reference to FIG. 8, the electrical connection means 6 is a contact pressure type power supply connector, and is electrically connected to the power supply terminal layer 4, and is provided in a pair substantially diagonally to the substrate 2. ing. The power supply connector includes a case 61 made of a white synthetic resin with little light absorption, and a contact member 62 having a curved contact portion on the tip side disposed in the case 61. The contact member 62 has elasticity, is formed of phosphor bronze or a Corson alloy, and has a surface plated with gold (Au). The power feeding terminal layer 4 in contact with the contact member 62 is screen-printed with gold (Au), which makes it possible to prevent foreign metal contact corrosion.

  The power supply connector is fixed to the recess 51 of the mounting member 5 from the surface side of the substrate 2 by a fixing means such as a screw. As a result, an elastic contact pressure in a direction from the front surface side of the substrate 2 of the contact member 62 toward the mounting member 5 side (back surface side of the substrate 2) is applied to the power supply terminal layer 32, and the contact member 62 is electrically connected to the power supply terminal layer 32. Connected.

  Along with the electrical connection of the power supply connector, an elastic pressing force is applied to the substrate 2, and the substrate 2 is held by the mounting member 5. Therefore, the electrical connection means 6 has a function of holding the substrate 2 on the mounting member 5 simultaneously with the electrical connection with the feeding terminal layer 4. Incidentally, the elastic contact pressure (elastic load) of the contact member 62 is set to 200 to 300 g.

  In addition, when holding to the attachment member 5 of the board | substrate 2 separately using another means, it is appropriate to set the elastic contact pressure (elastic load) of the contact member 62 to 70g-200g. .

  When power is supplied to the light-emitting device 1 having the above configuration by the lighting circuit, the positive-side power supply terminal layer 32a from one electrical connection means 6 and the bonding wire 41, the light-emitting element 4, and the negative-side power supply from the positive-side power supply conductor layer 31a. Electricity is supplied from the conductor layer 31b and the negative electrode side power supply terminal layer 32b to the other electrical connection means 6, and the light emitting elements 4 covered with the sealing member 22 emit light all at once, and the light emitting device 1 emits white light. Used as an outgoing planar light source.

  During the lighting, the heat generated by each light emitting element 4 is mainly conducted from the back surface side of the substrate 2 to the mounting member 5 to be radiated. Further, among the light emitted from the light emitting element 4 during the lighting of the light emitting device 1, the light directed to the substrate 2 side is a feeding conductor formed by the surface of the white substrate 2 or silver (Ag) having a high reflectance. Reflected mainly in the light utilization direction on the surface layer of the layer 31.

  Further, since the power supply terminal layer 32 is formed of gold (Au) having excellent conductivity and corrosion resistance, the contact function of the contact portion between the power supply terminal layer 32 and the contact member 62 is deteriorated even when used for a long time. And reliability can be secured.

  Furthermore, since gold (Au) is not the entire surface of the wiring pattern 3 but a partial formation of the power supply terminal layer 32, it is possible to avoid an increase in cost. At the same time, since the surface layer of the power supply conductor layer 31 exposes silver (Ag) having a high reflectance, it is possible to prevent the reflection efficiency from being lowered.

  Here, the power supply terminal layer 32 means a layer including at least a contact portion with the contact member 62. In short, the layer includes a portion that is electrically connected to the power supply side. Therefore, in the present embodiment, the contact member 62 includes a contact portion, and a portion extending from the contact portion by a predetermined region, specifically, the mutual multilayer portion D between the contact portion and the power supply conductor layer 31. It means to the part.

In addition, in the laminated portion (multilayer portion D) of the power supply conductor layer 31 and the power supply terminal layer 32, the gold (Au) of the power supply terminal layer 32 is below the silver (Ag) of the power supply conductor layer 31. Therefore, peeling of gold (Au) from the power supply terminal layer 32 can be suppressed. In addition, the deterioration of the contact function of the power supply terminal layer 3 can be suppressed. If the power supply terminal layer 32 is on the upper side of the power supply conductor layer 31, there is a step at the boundary between the power supply terminal layer 32 and the power supply conductor layer 31 in the multilayer portion D. For this reason, there is a possibility that the power supply terminal layer 32 that is susceptible to stress and load such as elastic contact pressure from the contact member 62 may be deteriorated, for example, at a stepped portion, and the contact function may be lowered.
Furthermore, since the power supply conductor layer 31 and the power supply terminal layer 32 are formed by screen printing, the formation thereof is inexpensive and easy.

  As described above, according to the present embodiment, by using gold (Au) for the power supply terminal layer 32 that is a part of the wiring pattern 3, the high cost can be suppressed and the light emitting device 1 with high reliability can be provided. Can do.

  Next, a light emitting device according to a second embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part which is the same as that of 1st Embodiment, or an equivalent part, and the overlapping description is abbreviate | omitted. In this embodiment, a nickel (Ni) layer 34 is formed in addition to the first embodiment. This formation is performed by screen printing in the same manner as the formation of each layer.

  (Embodiment 1) As shown in FIG. 9, in this embodiment, a nickel (Ni) layer 34 is formed under the power supply terminal layer 32 as a base layer. Thereby, it can suppress that the gold | metal | money (Au) layer of the electric power feeding terminal layer 32 peels from the surface of the board | substrate 2. FIG.

  (Embodiment 2) As shown in FIG. 10, in this embodiment, a nickel (Ni) layer 34 is interposed in an overlapping portion D of the feed terminal layer 32 and the feed conductor layer 31. Therefore, the nickel (Ni) layer 34 is laminated on the gold (Au) layer of the power supply terminal layer 32, and the silver (Ag) layer of the power supply conductor layer 31 is laminated thereon to form the multilayer portion D. This makes it difficult for the silver (Ag) layer of the power supply conductor layer 31 to peel from the gold (Au) layer of the power supply terminal layer 32.

  (Embodiment 2) As shown in FIG. 11, in this embodiment, a nickel (Ni) layer 34 is formed under the power supply terminal layer 32, and nickel is further formed on the gold (Au) layer of the power supply terminal layer 32. The (Ni) layer 34 is laminated, and the nickel (Ni) layer 34 is interposed in the multilayer portion D of the power supply terminal layer 32 and the power supply conductor layer 31.

  Therefore, the gold (Au) layer of the power supply terminal layer 32 can be prevented from peeling from the surface of the substrate 2, and the silver (Ag) layer of the power supply conductor layer 31 is the gold (Au) layer of the power supply terminal layer 32. It can suppress peeling from.

Next, the lighting device according to the embodiment of the present invention will be described. Although not shown, the light-emitting device 1 of each of the above embodiments is assembled in a device body such as a road light, a lighting device for a vehicle, a light source as an LED lamp, various lighting fixtures used indoors or outdoors, and a display device. Can be configured as a lighting device.
According to this illuminating device, the illuminating device which has the effect which the said light-emitting device 1 show | plays can be provided.

In addition, this invention is not limited to the structure of the said embodiment, A various deformation | transformation is possible in the range which does not deviate from the summary of invention. For example, a metal base substrate in which an insulating layer is laminated on one surface of a base plate such as aluminum may be used as the substrate.
Moreover, solid state light emitting elements, such as LED, can be applied to a light emitting element. Furthermore, there is no particular limitation on the number of light emitting elements mounted.

DESCRIPTION OF SYMBOLS 1 ... Light-emitting device, 2 ... Board | substrate, 3 ... Wiring pattern,
DESCRIPTION OF SYMBOLS 4 ... Light emitting element (LED chip), 6 ... Electrical connection means (contact-pressure type power supply connector), 31 ... Power supply conductor layer, 32 ... Power supply terminal layer, D ... Multilayer part

Claims (5)

A substrate having at least an insulating surface;
Formed on the surface side of this substrate, and has a power supply conductor layer and a power supply terminal layer made of gold or an alloy mainly composed of gold, and a part of each of the power supply conductor layer and the power supply terminal layer is laminated. An electrically connected wiring pattern;
A light emitting element electrically connected to the wiring pattern and mounted on the substrate;
A light-emitting device comprising:   2. The light emitting device according to claim 1, wherein the feed conductor layer and the feed terminal layer are stacked such that the feed terminal layer is below the feed conductor layer.   The light-emitting device according to claim 1, wherein the wiring pattern having the power supply conductor layer and the power supply terminal layer is formed by screen printing.   The light emitting device according to any one of claims 1 to 3, wherein an electrical connection means is connected to the power supply terminal layer by elastic contact pressure. The device body;
The light emitting device according to any one of claims 1 to 4, wherein the light emitting device is disposed in the device main body;
An illumination device comprising:

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