JP2008263204A - High-current surface mount type light-emitting diode lamp and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture an LED having excellent heat radiation properties at low costs. <P>SOLUTION: A surface mount type light-emitting diode lamp has: an upper metal layer composed of first and second electrically insulated regions; an insulator layer provided at the lower portion of the upper metal layer; a lower metal layer provided at the lower portion of the insulator layer; a light-emitting diode chip 23 provided on the first region of the upper metal layer and electrically connected to the first and second regions of the upper metal layer; and a space 21 for solder-up formed by removing one portion of the insulator layer and lower metal layer for exposing the upper metal layer. The surface mount type light-emitting diode lamp may have a ladder structure supporting solder-up. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface-mounted light-emitting diode (LED) lamp, and more specifically, heat emission to a substrate of a type in which a metal layer is provided on the surface of an insulator layer, which is generally used for a printed circuit board. A light emitting diode chip is mounted on a device with a configuration for the above, and heat can be effectively released even when driven at a large current, so that the efficiency can be manufactured at a low cost without substantially impairing its efficiency. The present invention relates to a novel light emitting diode lamp.

  Conventional LED lamps have been packaged by combining LED chips with a lead frame, which are further mounted on a circuit board or the like, and have been used as modular components. In addition, since the LED lamp having the LED chip on the conventional lead frame has a problem of low heat dissipation efficiency, a ceramic structure having a heat release passage, a metal slag or an aluminum nitride (AIN) -ceramics substrate in particular. There have been attempts to solve the problem of heat dissipation by adopting a lead frame including. However, these LED lamps having an improved heat dissipation mechanism have a problem that the production cost is high and the yield deteriorates because a complicated structure and a relatively expensive material are used.

  In addition, LED lamps have been proposed that use a printed circuit board provided with lead wires, and LED chips are provided on the printed circuit board, but this has low light utilization efficiency and sufficient heat dissipation. It is difficult to use for applications that require a large driving voltage.

  LED elements are vulnerable to heat due to their properties. Especially when driven under a large current, the energy efficiency of the LED chip is drastically reduced due to the heat generated by the LED chip itself, and the lifetime may be shortened. It has been mainly used as a low-output light source such as operation indicator lamps, but in recent years, it has also been used for outdoor displays such as road signals, and it can also be used as a substitute for fluorescent lights and light bulbs. The role is expected. Thus, there is a strong demand for the development of a new LED lamp that can efficiently dissipate heat even under a large driving voltage and can reduce the manufacturing cost.

  The present invention provides a novel surface mounting that prevents excessive heat generation, which is particularly problematic when a circuit board is used as a substrate for mounting an LED chip, enables a large current drive, and achieves high energy efficiency. An object is to provide a type LED lamp. Moreover, the novel manufacturing method which can manufacture such a surface mount type LED lamp at low cost is provided.

The present invention has the following features in order to solve the problems of the prior art and achieve the above object.
That is, the present invention relates to an upper metal layer composed of an electrically isolated first region and a second region, an insulator layer provided below the upper metal layer, and a lower metal layer provided below the insulator layer. , And a light emitting diode chip provided on the first region of the upper metal layer and having the diode poles electrically connected to the first region and the second region of the upper metal layer, respectively. The lamp is a space formed by removing a part of the insulator layer and the lower metal layer and exposing the upper metal layer, and has a solder rising structure. The light emitting device further comprising a space having a solder rising structure (immersion structure) in which solder flows into and solidifies into at least a part of the space in a solder immersion process due to surface tension. It relates to a gastric diode lamp.

The present invention also provides an upper metal layer composed of a first region and a second region that are electrically insulated, an insulator layer provided below the upper metal layer, and a lower metal layer provided below the insulator layer. , And a light emitting diode chip provided on the first region of the upper metal layer and having the diode poles electrically connected to the first region and the second region of the upper metal layer, respectively. The lamp is characterized in that a part of the insulator layer and the lower metal layer is removed, and solder is introduced and solidified into a part of the space formed by exposing the upper metal layer.
The present invention relates to the light emitting diode lamp.

The present invention further includes at least one solder rising structure that extends through the insulator layer and electrically connects the upper metal layer and the lower metal layer and is exposed to the solder rising space. It is related with the said light emitting diode lamp characterized by the above-mentioned.
Furthermore, the present invention relates to the light emitting diode lamp, characterized in that an electrically insulating portion having light reflectivity is provided between the first region and the second region of the upper metal layer.

In addition, the present invention provides the light-emitting diode, wherein the space formed by removing the insulator layer and the lower metal layer includes a rectangular or rectangular cross section, and a corner having a curved surface. Regarding lamps.
Furthermore, the present invention is characterized in that the light emitting diode is characterized by having a ladder structure for assisting solder rising on at least a part of the wall surface of the space formed by removing the insulator layer and the lower metal layer. Regarding lamps.

  Further, according to the present invention, a ladder structure that assists solder rising is provided on at least one through hole that penetrates the upper metal layer, the insulator layer, and the lower metal layer, and at least a part of a side surface of the through hole. The light-emitting diode lamp is characterized by comprising a plating or solder elevating material.

  The present invention is further characterized by further comprising an engaging portion that extends through the upper metal layer into the insulator layer in order to assist the bonding between the upper metal layer and the insulator layer. The present invention relates to the light emitting diode lamp.

  The present invention also provides a method of manufacturing a surface-mounted light-emitting diode lamp, comprising a circuit board including an upper metal layer, a lower metal layer, and an insulator layer provided between the upper metal layer and the lower metal layer. Providing an electrically insulating portion to electrically insulate the upper metal layer from the first region and the second region; and forming the lower metal layer and the insulator layer so that the upper metal layer is partially exposed. And removing to form a space (soaking structure space) for solder up.

Furthermore, the present invention relates to the above method, further comprising the step of forming the solder layer that occupies at least a part of the space in which the solder rises into the space for solder rise.
Furthermore, the present invention relates to the above method, wherein the lower metal layer and the insulator layer are removed by dicing or etching.

The present invention also relates to the above method, wherein a ladder structure for assisting solder rise is formed in at least a part of a space formed by removing the insulator layer and the lower metal layer.
Further, according to the present invention, at least one through-hole penetrating the upper metal layer, the insulator layer, and the lower metal layer is formed so as to be exposed to the solder rising space (immersion structure space), and at least one side surface of the through-hole is formed. The present invention relates to the above method, characterized in that a ladder structure for assisting solder reflow is formed by applying metal plating or solder elevating material to the part.

  Furthermore, the present invention further includes the step of further forming an engaging portion extending through the upper metal layer and into the insulator layer to assist the bonding between the upper metal layer and the insulator layer. To the above method.

In the present invention, when the solder flows into and solidifies into the space for the solder rise (immersion structure space), the light emitting diode lamp is mounted effectively through the exposed metal layer and the solder to generate heat from the light emitting diode chip. Since it can escape to the circuit board side, a large current drive becomes possible. In addition, the solder can easily go up to the space for solder rise in the reflow process, and the formation of the heat release means is very easy. In addition, the formation of the solder rising space itself is simple and easy as compared with a conventional construction method for heat release.
Compared to the conventional method using a lead frame and a dispensing method, the present invention is small and thin, has excellent heat dissipation characteristics, can be driven with a large current, and greatly improves energy efficiency. can do. In particular, even in the case of mass production of LED lamps, it is excellent in terms of uniformity of performance, yield, mass productivity, and the like, and thus the overall cost can be reduced. As a result, it is expected to contribute to the creation of demand for LEDs and greatly contribute to the development of the industry.

The basic structure of the LED lamp according to the present invention will be described below with reference to FIGS.
FIG. 1 shows a circuit board to be a board for mounting an LED chip, which includes an upper metal layer 11 including a first area 12 and a second area 13 that are electrically separated by an electrical insulating portion 14; Insulating layer 16 located below upper metal layer 11 and lower metal layer 15 are included.

  In the present invention, the upper metal layer 11 and the lower metal layer 15 can be made of a metal (for example, copper, aluminum, etc.) generally used for a printed circuit board, but it is particularly preferable to use copper.

  The thickness of the upper metal layer 11 is 10 μm or more, preferably about 100 to 800 μm, and the thickness of the lower metal layer 15 is preferably thinner than the upper metal layer 11. Further, as shown in FIG. 1, the lower metal layer 15 may be formed of two electrically separated regions. In such a configuration, as will be described later, the lower metal layer 15 can function as an electrode by connecting the lower metal layer 15 to the upper metal layer 11 with a conductor.

  The electrical insulating portion 14 that electrically separates the upper metal layer 11 removes a part of the upper metal layer 11 of the prepared circuit board using a technique such as laser, punching, or etching, and fills with an electrical insulator. By forming. At this time, it is preferable to use an electrically insulating material having high light reflectivity as the electrical insulator. By providing the light reflective insulating portion, it is possible to collect light emitted from the LED element more efficiently and provide light with high luminance. An example of such an electrically insulating substance having light reflectivity is a white resist.

  The insulator layer 16 constituting the circuit board is located between the upper metal layer 11 and the lower metal layer 15 to electrically insulate them. As a material constituting the insulator layer 16, FR-1, FR-4, or other resins can be used. The thickness of the insulator layer 16 is preferably 400 μm or more, but can be determined as appropriate so that soldering or reflow described later can be performed.

FIG. 2 schematically shows one embodiment of the surface-mount LED lamp according to the present invention using the circuit board described above.
The LED chip 23 is mounted on the upper metal layer 11, and each pole of the LED element is electrically connected to the first region 12 and the second region 13 via the wire 24. That is, in the LED lamp of the present invention, the first region 12 and the second region 13 of the upper metal layer 11 are used as electrodes. For example, as shown in FIG. 2, the second region 13 and the insulator of the upper metal layer 11 are used. A portion of the lower metal layer 15 is formed by providing a conductor 22 (electrode lead) so as to penetrate the layer 16 and electrically connecting the second region 13 of the upper metal layer 11 and one of the lower metal layers. It can also be used as an electrode. The first region 12 and one electrode of the LED chip 23 are:
Direct conduction may be achieved.

Next, a particularly characteristic heat dissipation structure of the LED lamp of the present invention will be described in detail with reference to FIGS. In the LED lamp of the present invention, the insulating layer 16 and the lower metal layer 15 are partially or entirely removed to expose the upper metal layer 11, thereby at least one solder inflow space 21 (heat discharge passage). have. The solder inflow space 21 is preferably formed in a straight line shape or a taper shape by dicing or etching (corrosion method), and the cross section thereof is rectangular or rectangular, but is not limited thereto. The space 21 of the present invention can be formed from 1 to several tens as required, such as desired heat dissipation and LED lamp driving characteristics. FIG. 2 shows an embodiment in which a relatively small area on the back surface of the circuit board is removed to provide a solder inflow space 21, but the present invention is not limited to this, and most of the circuit board is substantially removed. It is also possible to form a space for solder inflow.

  As a specific method for introducing or filling the solder into the solder inflow space 21, it is preferable to use reflow soldering when the LED lamp of the present invention is mounted by soldering. That is, when heat is applied when the LED lamp is mounted to melt the soldering material, the solder material rises in the space 21 due to capillary action, and as a result, the space 21, or at least a part thereof, becomes solder material. It is preferable to position the solder material on the solder rising space 21 and the mounting substrate so that the solder material is substantially satisfied. As a material for soldering, a metal having high thermal conductivity such as lead or tin which is usually used can be applied to the present invention as it is. By applying solder reflow according to the present invention, manufacturing costs can be drastically reduced compared to conventional LED lamps that use metal leads to dissipate heat using expensive conductive metals such as copper. Can do.

  Next, with reference to FIGS. 3a and 3b, a ladder structure 31 for assisting the solder to rise into the space 21 formed by removing the lower metal layer 15 and the insulator layer 16 will be described. 3A is a cross-sectional view taken along the line A-A ′ of FIG. 2, and FIG. 3B is a perspective view taken along the line B-B ′ of FIG. 2. The ladder structure 31 for assisting soldering up of the present invention has a soldering elevator material (for example, a metal containing silver paste, silver or copper) having a high affinity with a soldering material for at least a part of the side surface of the space 21. For example, a mixture of a material and a resin) or a plating process or the like with another metal having a high affinity for the soldering material. As shown in the figure, the ladder structure 31 of the present invention is formed so as to connect the upper metal layer 11 and the lower metal layer 15, and a part of the ladder structure 31 is joined together when the insulator layer 16 is removed. By removing, the cross section 31 a of the ladder structure 31 is exposed at the boundary with the solder inflow space 21.

  Further, the ladder structure 31 of the present invention is not limited to an embodiment formed in the space from which the lower metal layer 15 and the insulator layer 16 are removed, and as shown in FIGS. 3a and 3b, an appropriate heat release passage is formed. As long as it has a function of assisting, for example, it may be formed on the side surface of the through hole penetrating the upper metal layer 11, the insulator layer 16, and the lower metal layer 15.

  By providing the ladder structure 31, that is, the solder rising structure in this way, when the LED lamp is mounted on the mounting substrate by soldering, the capillary phenomenon in which the soldering material rises in the space 21 provided on the back surface of the LED lamp. Can be promoted.

  What is important here is that the solder reflow is sufficiently high so that it properly functions as a path for releasing the heat generated from the LED chip 23, that is, the solder material reaches the upper electrode layer 11 and passes through the heat conductive path. It is to determine various matters such as the thickness of the insulator layer 16 and the lower electrode layer 15 and the height of the ladder structure 31 so as to be formed.

[Example 1]
One embodiment of the LED lamp according to the present invention is shown in FIG. Since the basic configuration is the same as that already described above, a duplicate description is omitted. In this embodiment, the light extraction part 41 is formed of a light transmissive material such as silicone or epoxy so as to cover the LED chip 23. The light extraction unit 41 can be formed by molding over the LED chip 23, and has an effect of protecting the LED chip 23 and changing the optical characteristics of the output light. That is, by including various additives such as a fluorescent agent for converting the wavelength of light emitted from the LED element, a diffusing agent for diffusing light, or a dye for changing the color of light in the mold material, It is possible to add or change the function as a light emitting lamp.

  The light extraction unit 41 preferably has a thickness of about 200 to 100 μm, and it is preferable to use a material having a refractive index of about 1.4 to 2.5 such as silicone and epoxy described above. In particular, in order to prevent light from being absorbed by the LED chip 23, it is desirable to use a material having a lower refractive index than the material constituting the LED chip 23.

[Example 2]
Referring to FIGS. 5a and 5b, the upper metal layer 11 and the insulator layer 16 are extended to enhance the coupling between the LED chip and the mold layer such as the light extraction portion 41 formed by molding. An LED lamp according to another aspect of the present invention in which the engaging portion 51 is formed will be described. In the figure, the already described structures such as the LED chip or the solder rising space on the back of the substrate are omitted as appropriate.

  That is, the engaging part 51 removes the upper metal layer 11 and a part of the insulator layer 16 in a substantially vertical direction, and injects a molding material such as the light extraction part 41 into the removed space. By this engagement portion 51, the mutual bonding property between the mold layer and the chip can be enhanced. The holes that are removed in advance to form the engaging portion 51 can be in the shape of a cylinder, a quadrangular column, a rectangular column whose lower side is longer than the upper side, or the like.

[Example 3]
With reference to FIG. 6, another aspect of the present invention that further includes a light guide 61 formed adjacent to the side surface of the light extraction unit 41 will be described. The light guide 61 serves to guide light so that light emitted from the light emitting diode chip 23 is emitted above the chip 23. The light guide 61 is formed of a material having a high reflectance such as a white resist, or a material in which a white pigment or metal particles having excellent light reflectivity are dispersed, and can be attached by molding or tape bonding. Further, if necessary, the light guide can be formed so as to have a predetermined inclination with respect to the light extraction portion, and is preferably set to an inclination angle of 45 to 90 degrees.

[Example 4]
With reference to FIG. 7, the LED lamp of another aspect of this invention is demonstrated. In this aspect, in order to increase the light emission efficiency from the LED element, the reflection structure 71 is provided at a place where the LED chip is placed. The reflection structure 71 is obtained by removing a part of the first region 12 so as to form a recess in the first region 12 of the upper metal layer 11. The recess on the first region 12 can be formed by wet etching, preferably half etching. Preferably, the reflecting structure 71 has a shape having a plurality of radii of curvature so that both the light in the lower surface direction and the light in the side surface direction of the recess are guided upward. In addition, it is preferable to appropriately select the size, shape, and the like so that light reabsorption does not occur. Furthermore, the reflective structure 71 may be coated with a highly reflective metal material such as silver. The light emitted from the LED chip is guided in a desired direction by the reflection structure 71, and more efficient light can be generated.

  According to the present invention, an LED lamp having a high heat dissipation efficiency can be easily and inexpensively manufactured. Therefore, it is expected that the application as a high-output light source using the LED element will be further expanded and contribute greatly to the development of the industry.

It is a front schematic diagram showing a circuit board suitably used in the present invention. FIG. 10 illustrates one embodiment of the present invention. It is a figure explaining the ladder structure for solder reflow auxiliary of the present invention. It is a figure explaining the ladder structure for solder reflow auxiliary of the present invention. It is a figure explaining the ladder structure for solder reflow auxiliary of the present invention. It is a figure explaining the ladder structure for solder reflow auxiliary of the present invention. It is a figure which shows another aspect of this invention. It is a figure explaining another aspect of this invention. FIG. 5b is a plan view of the substrate shown in FIG. 5a. It is a figure which shows another aspect of this invention. It is a figure explaining another aspect of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Upper metal layer 12 1st area | region 13 2nd area | region 14 Electrical insulation part 15 Lower metal layer 16 Insulator layer 21 Space 22 for solder inflow 22 Conductor 23 LED chip 24 Wire 31 Ladder structure 31a Ladder structure cross section 41 Light extraction part 51 Engagement part 61 Light guide 71 Reflection structure

Claims (12)

An upper metal layer comprising a first region and a second region which are electrically isolated;
An insulator layer provided below the upper metal layer,
A lower metal layer provided below the insulator layer, and a first region of the upper metal layer, and each pole of the diode is electrically connected to the first region and the second region of the upper metal layer, respectively. A surface-mounted light-emitting diode lamp equipped with a light-emitting diode chip,
A part of the insulator layer and the lower metal layer is removed, and a solder rising space is formed by exposing the upper metal layer, and the space part further includes a structure for allowing molten solder to rise. The light-emitting diode lamp characterized by the above. An upper metal layer comprising a first region and a second region which are electrically isolated;
An insulator layer provided below the upper metal layer,
A lower metal layer provided below the insulator layer, and a first region of the upper metal layer, and each pole of the diode is electrically connected to the first region and the second region of the upper metal layer, respectively. A surface-mounted light-emitting diode lamp equipped with a light-emitting diode chip,
A part of the insulator layer and the lower metal layer is removed, and the upper metal layer is exposed to have a solder up space formed;
In the soldering step when mounting the light emitting diode lamp, the solder goes up into the space and occupies at least a part of the space.   The structure according to claim 1, further comprising a structure that extends through the insulator layer and is exposed to at least one of the solder rising spaces that electrically connects the upper metal layer and the lower metal layer. The light emitting diode lamp of 2.   The light-emitting diode lamp according to claim 1, further comprising an electrically insulating portion having light reflectivity between the first region and the second region of the upper metal layer.   The cross section of the space formed by removing the insulator layer and the lower metal layer is almost rectangular or rectangular, and the three-dimensional shape of the space may be a straight line or a rotating body. The light emitting diode lamp according to claim 1, wherein the light emitting diode lamp is good.   In the space formed by removing the insulator layer and the lower metal layer, or in at least a part of the wall, has a ladder structure that assists solder rising, and the ladder structure is exposed to at least one of the spaces. 6. The method according to claim 1, wherein the side wall of the through-hole penetrating vertically is plated with metal, or the side surface of the space is plated with metal or a solder elevator material. A light emitting diode lamp according to claim 1.   8. An engaging portion extending through the upper metal layer and into the insulator layer to assist the bonding between the upper metal layer and the insulator layer. A light emitting diode lamp according to any one of the above.   A method of manufacturing a surface-mounted light emitting diode lamp, comprising: preparing a circuit board including an upper metal layer, a lower metal layer, and an insulator layer provided between the upper metal layer and the lower metal layer; An insulating portion is provided to electrically insulate the upper metal layer into the first region and the second region, and the lower metal layer and the insulator layer are removed and melted so that the upper metal layer is partially exposed. Forming a space having a structure for rising solder.   The method according to claim 9, further comprising mounting the light emitting diode lamp by soldering, wherein the solder flows into the space having a structure in which the molten solder rises and solidifies.   The method according to claim 9 or 10, wherein the lower metal layer and the insulator layer are removed by dicing, etching or etching lift-off.   The method further includes forming a ladder structure for assisting solder rising in a space formed by removing the insulator layer and the lower metal layer or in at least a part of the wall, the ladder structure including at least one of the spaces. A metal plate is formed on a side wall of a through-hole penetrating vertically and exposed on the surface, or a metal or solder elevator material is plated on a side surface in the width direction of the space. The method according to any one of 9 to 11.   The method further comprises forming an engagement portion extending through the upper metal layer into the insulator layer to assist in bonding the upper metal layer and the insulator layer. Item 14. The method according to any one of Items 9 to 13.

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