JP2009290167A - Light emitting module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting module integrated with light emitting diodes. <P>SOLUTION: In this light emitting module using light emitting diodes, a wiring pattern is formed on one surface of an insulation substrate bored with multiple device holes; a pair of heat-radiating inner leads are extended in each device hole from the wiring pattern; electrode terminals of the light emitting diodes fitted in the device holes electrically are connected to the heat-radiating inner leads extended in the device holes; and at least a part of heat generated when the light emitting diodes emit light is exhausted to the outside through the wiring pattern from the heat-radiating inner leads extended in the device holes and electrically connected to the light emitting diodes. The invention provides excellent radiation efficiency of heat and excellent efficiency of conversion of electricity to light. The light emitting module can be efficiently manufactured by collectively bonding the multiple LEDs. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light emitting module using a number of light emitting diodes (LEDs).

LED, which stands for Light Emitting Diode, is an abbreviation for Emitting Diode (Diode). It is a kind of semiconductor that emits light when electricity is applied. Has attracted attention as another light source.

  Conventional light emitting diodes have a height of about 5 mm, and the connection terminals are line terminals. Therefore, the mounting operation is very complicated, and it is considered that development of blue light emitting diodes is practically difficult. Therefore, it was used only for extremely limited purposes. However, since the blue diode was invented and the three primary colors of light were aligned, and the light-emitting diode itself was further miniaturized, development as a light-emitting module was rapidly advanced.

The first improvement of such a light emitting diode is miniaturization, and a light emitting diode having a length of about 3 mm, a width of about 1.5 mm and a thickness of about 0.3 mm has already been developed.
However, such a small light emitting diode is of a type that establishes electrical connection with a wiring pattern by wire bonding. Therefore, there is no means for effectively releasing the heat generated by energizing the light emitting diode, and it is often difficult to mount the light emitting diode downsized as described above at high density.

  As an electronic component using such a light emitting diode, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2007-189006) discloses a reflection region made of silver-white metal plating that reflects light and a proximity of the reflection region. An invention of a printed wiring board provided with a gold-plated terminal portion is disclosed. In Patent Document 1, in order to more efficiently reflect light from the light emitting diode, the metal plating layer is silver-white metal plated.

  However, in this patent document 1, the light emitting diode is mounted by wire bonding, and the mounting operation of the light emitting diode becomes very complicated. Further, the heat generated from the light emitting diodes is not sufficiently dissipated and is not suitable for long-time use.

That is, the light-emitting diode itself is not so high in electro-optical efficiency, and the light emission amount of one light-emitting diode is not so large, so it is necessary to use a large number of light-emitting diodes together to adopt as a new light source. There is. However, when a large number of such light emitting diodes are integrated, even if the amount of heat generated by each light emitting diode is small, the number of light emitting diodes increases, so that the amount of heat generated as a whole increases. In order to release the heat once integrated, it is necessary to provide heat dissipation means on a large scale, and it is considered difficult to integrate a large number of light emitting diodes, and this point is adopted as a new light source It has become a neck when doing.

By the way, in a field different from the light emitting diode, a TAB tape is used for mounting electronic components. In the current TAB tape, the development of TAB tape with an inner lead width of less than 30μm is underway. About 10 years ago, the thickness of the polyimide film forming the insulating substrate exceeded 70 μm, and the thickness of the electrolytic copper foil forming the wiring pattern here exceeded 70 μm. The line width was also about 100 μm.

At present, these large TAB tapes are rarely used, but the insulating substrate that forms such TAB tapes is a highly heat-resistant polyimide film, and the wiring pattern is copper with extremely high thermal conductivity. It is formed with.

Although these conventional TAB tapes are made of materials that have heat resistance and high heat dissipation properties, they do not have a structure for mounting light-emitting diodes. It cannot be used as a mounting substrate for mounting a light emitting diode as it is.

Note that Patent Document 2 (Japanese Patent Laid-Open No. 2-101778) and the like indicate that a light emitting diode is used to display the operation of an IC. This Patent Document 2 discloses a module in which a light emitting diode is connected to an external connection terminal of an IC and the light emitting diode in the driving portion of the IC confirms light emission. However, a technique of using the light emitting diode as a light source is disclosed. The idea is not shown in cited document 2.
JP 2007-189006 A Japanese Patent Laid-Open No. 2-101778

  An object of the present invention is to provide a light emitting module that can be used as a third light source by integrating light emitting diodes (LEDs).

  The light emitting module using the light emitting diode of the present invention has a wiring pattern formed on one surface of an insulating substrate having a large number of device holes, and a pair of heat dissipating inner layers from each wiring pattern into each device hole. Occurs when the light emitting diode emits light while the lead is extended and the electrode terminal of the light emitting diode fitted in the device hole is electrically connected to the heat dissipating inner lead extended in the device hole. At least a part of the heat to be discharged is exhausted to the outside through the wiring pattern from the heat dissipating inner leads extending in the device hole and electrically connected to the light emitting diode.

According to the present invention, it is possible to mount a very finely improved light emitting diode (LED) at high density and efficiently, and heat from the light emitting diode thus miniaturized through a heat dissipating inner lead. And efficiently dissipate heat to the outside through the wiring pattern.

As described above, the light emitting module of the present invention has a high heat dissipation efficiency, so that a light emitting diode (LED) is used.
Can be mounted at high density, and can be used as a third light source following incandescent lamps and fluorescent lamps.

  Moreover, since the substrate for mounting the light emitting diode according to the present invention can be manufactured using the technology and equipment for manufacturing the flexible wiring substrate, a high performance light emitting module can be easily manufactured.

According to the present invention, when a light emitting diode (LED) is mounted, the heat from the LED can be efficiently exhausted, and the light from the LED is efficiently reflected in the device hole. High brightness can be obtained when the is mounted.

In addition, according to the light emitting module of the present invention, a light emitting module in which light emitting diodes (LEDs) are mounted at a high density can be obtained. Moreover, since this light emitting module has good heat dissipation, a large number of light emitting diodes can be integrated. .

In addition, in the present invention, a large number of light emitting diodes (LEDs) can be collectively mounted on the wiring board, so that a light emitting module can be manufactured very efficiently.
In addition, this light emitting module can be manufactured at a very low cost because the technology and equipment used in the manufacture of the TAB tape can be used as they are.

Next, the light emitting module of the present invention will be described in detail with reference to the drawings. In the drawings to be referred to, common members are given the same numbering.
FIG. 1 is a wiring board having a wiring pattern using a TAB tape forming a light emitting module of the present invention, and FIG. 2 is a plan view showing an example of a state in which a light emitting diode is mounted on the wiring board. 3 is a sectional view taken along line XX in FIG.

  4 is an enlarged cross-sectional view showing a portion of the light emitting diode 30 in FIG. 2, and one light emitting diode (LED) 30 is provided in the device hole 14 formed in the polyimide film 10 which is an insulating substrate. Has been implemented.

  In the light emitting module of the present invention shown in FIG. 2, a large number of device holes 14 are formed in an insulating substrate 10 having sprocket holes 8 formed at both edges, and light emitting diodes (LEDs) are formed in the individual device holes 14, respectively. One 30 is fitted.

The light emitting diode 30 includes an LED 30 (R) that emits red light, an LED 30 (G) that emits green light, and an LED 30 (B) that emits blue light, which can be combined to emit light. In FIG. 2, the leftmost LED 30 is shown as (R), (
LEDs with different colored light are sequentially arranged as in B), (G), (R), (B), (G). Further, in the second column from the left, the LEDs are arranged in the same order as the arrangement of the LEDs in the leftmost column, but the LEDs are arranged with a phase shift of only one, and similarly, the columns adjacent to this are arranged. The LEDs are also arranged with a phase shift from the LEDs in the adjacent rows.

The LEDs may be arranged so that each row repeats the permutation of (R), (B), (G) as described above, or any one row is a row of (R), and one row adjacent to this. It is also possible to arrange light emitting diodes of different colored light for each column so that the column (B) is the column (B) and the column adjacent to the column (B) is the column (G).

  In addition, blue LEDs and / or ultraviolet LEDs are arranged in all device holes, and a phosphor that converts blue light or ultraviolet light into visible light is arranged on the LEDs, for example, in the light-emitting resin portion 38 to emit light from the LEDs. When white light is used, the light emitting module of the present invention can be obtained by mounting blue LEDs or ultraviolet LEDs in all device holes.

As shown in FIGS. 1 and 2, wiring patterns represented by reference numerals 21 (−) and 21 (+) are alternately formed on one surface of the insulating substrate 10 of such a light emitting module. For example, from the wiring pattern 21 (−) or the wiring pattern 21 (+), the heat dissipating inner lead 22 (−) or the heat dissipating inner lead 22 (+) is extended inside the device hole 14, respectively. Here, the length T ₂ of the heat dissipating inner lead 22 (+) or 22 (−) from the wiring pattern 21 (+) or 21 (−) does not hinder the emission of light from the LED 30, and the LED 30 emits light. It is set to efficiently absorb the heat generated by the heat and exhaust it through the wiring pattern 21 (+) or 21 (-).
The length (W) of D30 is 0.1 to 0.4 mm, and the width of the light emitting portion (not shown) at the center of the LED 30 is 0.05 to 0.30 mm. For (+) or 22 (-), it is desirable that the line width be as wide as possible. However, if the line width is excessively widened, the opening of the LED is not broken, so the range of the optimum value is limited in relation to heat conduction and radiation area. It is desirable to set. The length T ₂ of the heat dissipating inner lead 22 (+) or 22 (−) is formed at the end as much as possible and designed to be as small as possible, and may be as long as it can reach the LED electrode. .01 to 0.2 mm, preferably 0.05 to 0.15 mm.

  The heat dissipating inner lead 22 (−) or the heat dissipating inner lead 22 (+) in the present invention has a plating layer on the surface, and the metal supplied from the plating layer and the bump electrode 32 formed on the LED 30. , 33 is electrically joined to the heat dissipating inner lead by the metal supplied from 33.

The heat dissipating inner lead 22 (−) or the heat dissipating inner lead 22 (+) is different from the flying inner lead formed in the conventional device hole, and one LED 30 inserted in the device hole is connected to the device hole 14. Are joined and held by two flying inner leads extending from both ends. The LEDs 30 are electrically joined by these two flying inner leads and are held as circuit members, and further, the heat generated by driving the LEDs 30 is discharged. For this reason, the heat dissipating inner lead 22 (−) and the heat dissipating inner lead 22 (+), which are the two flying inner leads formed in the light emitting module of the present invention, transmit more heat through the wiring pattern. Unlike the conventional flying inner lead, the LED 30 is formed to be very thick and robust in order to dissipate heat and to physically hold the LED 30 and to securely connect the LED 30 reliably. Normally, a contact portion is formed at the end portion of the LED 30, and the heat dissipating inner leads are brought into contact with 60% or more of the end portion (one side) of the LED 30 including the contact portion, thereby being very efficient. In particular, the heat generated in the LED 30 can be transferred from the heat dissipating inner leads to the wiring pattern to be exhausted.

In the present invention, two bump electrodes 32 and 33 are formed on the LED 30, and the plating formed on the surfaces of the heat dissipating inner lead 22 (-) and the heat dissipating inner lead 22 (+) as described above. The LED 30 and the heat dissipating inner lead 22 (−) and the heat dissipating inner lead 22 (+) are electrically connected by the metal supplied from the layer and the metal supplied from the bump electrodes 32 and 33 of the LED 30. . Here, examples of the metal forming the bump electrode 32.33 include gold, silver, solder metal, lead-free solder metal, and the like, and the plating layer formed on the surface of the heat dissipating inner lead includes gold plating. Examples include a layer, a silver plating layer, a gold-nickel plating layer, a tin plating layer, a nickel plating layer, a solder plating layer, and a lead-free solder plating layer. Particularly in the present invention, the metal forming the bumps 32 and 33 of the LED 30 is preferably gold or a gold alloy, and the plating layer formed on the surface of the heat dissipating inner lead is preferably a tin plating layer. In this way, by using the LED 30 having gold bumps and eluting tin from the heat dissipating inner lead having a tin plating layer, a gold-tin eutectic is formed at the junction, and a large number of LEDs 30 and a large number of heat dissipating inner leads are formed. Can be firmly bonded together.

In the present invention, the width T ₁ of the heat dissipating inner lead 21 is 100% of the width T ₀ of the LED 30.
In this case, the LED 30 is formed so that it is usually in the range of 20 to 100%, preferably in the range of 30 to 70% with respect to the width T _{0 of the} LED 30. Further, the length of the heat dissipating inner lead 22 from the device hole is such that when the length L of one piece of the device is 100%, the length covering the device is 30% or less, preferably 10 to 30%, particularly preferably Is set within a range of 10 to 20%. In the light emitting module of the present invention, as shown in FIG. 3, the LED 30 surface joined to the heat dissipating inner leads 22 (−) and 22 (+) becomes the light emitting surface, so that the heat dissipating inner leads 22 (−) , 22 (+), the light emitted from the LED 30 can be extracted more effectively to the outside.

  In the present invention, the device hole 14 to be formed employs a polyimide whose one side is 50 μm or more larger than the size of the LED 30 and whose thickness is substantially the same as or slightly thicker than the LED.

  Further, as shown in FIG. 3 and FIG. 4, by attaching a reflector 36, preferably an insulating reflector 36, to the lower surface of the device hole 14 on which the LED 30 is mounted, the LED 30 mounted in the device hole emits light. The extracted light can be extracted with very high efficiency. Examples of such a reflector 36 include an aluminum foil or a resin-coated metal foil such as an aluminum foil whose surface is resin-coated. In addition, it is preferable to use a thermosetting adhesive such as an epoxy resin as an adhesive when the reflecting plate 36 is pasted. This thermosetting adhesive is used as an adhesive, and this heat A cured product of a curable adhesive can also be used as the insulating film of the metal foil.

In addition, after mounting the LED 30 as described above, the transparent resin is filled from the side (output surface) on which the heat dissipating inner leads of the device hole 14 are formed, and the light is raised as shown in FIGS. By forming the resin portion 38, the light emitted in the device hole can be diffused at a wide angle. Further, by filling the transparent resin in this way, the bonding strength between the LED 30 and the heat dissipating inner lead 22 (−) and the heat dissipating inner lead 22 (+) is also increased.

  As described above, a resin having high transparency and heat resistance can be used as the transparent resin used as the light-emitting resin portion 38. Examples of such a resin include a heat or photo-curing acrylic resin, an epoxy resin, and the like. Can be mentioned. These can be used alone or in combination.

The light emitting module of the present invention as described above can be manufactured, for example, as shown in FIG.
In the example shown in FIG. 5, first, an insulating substrate 10 with an adhesive layer 12 is prepared as shown in FIG.

  The insulating substrate 10 used here is preferably an insulating substrate formed of a resin that exhibits good heat resistance and is excellent in water resistance and chemical resistance. Examples of such an insulating substrate include a polyimide substrate, a polyamideimide substrate, an epoxy resin substrate, a phenol resin substrate, a BT resin substrate, and a liquid crystal resin substrate. Among these, an insulating substrate made of a polyimide film that exhibits excellent heat resistance and also has flexibility is preferable.

  Since the insulating substrate 10 used in the present invention is used by housing the LED 30 in the device hole 14, it is necessary to have a thickness sufficient to accommodate the LED 30, usually 50 to 250 μm, Preferably, a polyimide film having a thickness of 70 to 125 μm is used.

  An adhesive layer 12 is provided on one surface of the insulating substrate. The adhesive forming the adhesive layer 12 is preferably a thermosetting adhesive, an epoxy resin adhesive, a polyimide adhesive, a thermosetting acrylic adhesive, a thermosetting urethane adhesive. A thermosetting adhesive such as can be used. The thickness of this adhesive layer is usually about 10 to 35 μm.

  A large number of device holes 14 are formed using the insulating substrate 10 with the adhesive layer 12 as described above, as shown in FIG. As shown in FIG. 1, the device holes are formed as densely as possible by arranging a large number of LEDs and leaving a gap between the device holes 14 for forming the wiring pattern 21 for supplying power to the LEDs 30. It is preferable.

The shape of the device hole 14 to be formed may be rectangular, circular, or any other shape as long as it can accommodate the LED 30.
FIG. 1 shows an example using a polyimide film having a width of 35 mm. FIG. 1 shows that a sprocket hole 8 is formed on both sides of the polyimide film and 25 mm between the sprocket holes 8 on both sides. This is an example of a wiring board in which a large number of circular device holes 14 having a diameter of 0.5 mm are formed in an insulating substrate having a width, and wiring patterns 21 (−) and 21 (+) are formed between the device holes 14.

  Laser light or the like can be used to form the device hole 14, but it is efficient to perform punching. In this punching, sprocket holes 8 are formed in both edge portions of the insulating substrate 10 tape. The sprocket hole 8 can be used not only for transporting the tape but also as a tape positioning means.

  The metal foil of the insulating substrate 10 with the adhesive layer 12 after bonding the predetermined device hole 14 as described above is bonded. As the metal that can be used here, a metal that is excellent in conductivity and thermal conductivity and that can be easily processed by etching is used. Examples of such metals include copper, aluminum, tin, gold, and silver, but it is preferable to use copper from the viewpoint of workability and economy. When copper is used in the present invention, a copper alloy may be used.

  When copper is used as the metal foil 20 in the present invention, the copper foil includes an electrolytic copper foil and a rolled copper foil, but any copper foil can be used in the present invention. However, considering the adhesive strength with the insulating substrate 10, it is preferable to use an electrolytic copper foil. The electrolytic copper foil 20 has a shiny surface (S surface) where copper deposition begins and a mat surface (M surface) where copper deposition ends. The adhesive layer of the insulating substrate 10 with the adhesive layer 12 12 and the matte surface (M surface) of the electrolytic copper foil are arranged so as to face each other, and pressurizing under heating, a copper-clad laminate as shown in FIG. 5 (c) can be obtained. it can.

The thickness of the metal foil 20 that can be used here, preferably the thickness of the electrolytic copper foil 20 is not particularly limited, but in the light emitting module of the present invention, the wiring pattern formed by the metal foil 20 or the electrolytic copper foil 20 is different. It is preferable to use a relatively thick metal foil 20 because it not only supplies power to the LED 30 but also serves as a heat conductor that exhausts heat generated in the LED 30 to the outside of the module. When using an electrolytic copper foil as such a metal foil, an electrolytic copper foil of about 20 to 150 μm can be used. In the present invention, it is particularly preferable to use an electrolytic copper foil of 50 to 100 μm. The wiring pattern formed using the electrolytic copper foil 20 having such a thickness has good thermal conductivity and low electrical resistance when energized, and therefore when supplying power to drive the LED 30 In addition, the wiring pattern 21 itself does not generate heat. Further, in the light emitting module of the present invention, the heat dissipating inner leads 22 (+) and 22 (−) which are a pair of flying leads are formed in the device hole 14, and the LED 30
When the LED 30 is held by being connected to the LED 30, by using the electrolytic copper foil having the thickness as described above, the heat dissipating inner leads 22 (+), 22
It is possible to form a very tough inner lead that does not bend (−) and does not even deform.

Heat radiation connected to the wiring pattern 21 (+) and the heat dissipating inner lead 22 (-) connected to the wiring pattern 21 (-) and the wiring pattern 21 (-) by etching the metal foil 20 The inner lead 22 (-) is formed.

That is, in the device hole 14 and on the surface of the electrolytic copper foil 20, the wiring pattern 21 (−), the heat dissipating inner leads 22 (−) connected to the wiring pattern 21 (−), and the surface of the electrolytic copper foil 20 A masking material 23 made of a cured photosensitive resin is formed on the wiring pattern 21 (+) and the heat dissipating inner lead 22 (+) connected to the wiring pattern 21 (+). The exposed electrolytic copper foil 20 and the electroless copper plating layer are etched. As the etching agent used here, a normal etching agent mainly composed of ferric chloride, cupric chloride, ferric sulfate, cupric sulfate and the like can be used.

By etching in this way, the metal foil 20 on which the masking material 23 is not formed is removed, and the wiring pattern 21 (−) and the heat dissipating inner leads 22 (−) connected to the wiring pattern 21 (−) are removed. ), And the metal foil 20 is removed leaving the portion of the wiring pattern 21 (+) on the surface of the electrolytic copper foil 20 and the heat dissipating inner lead 22 (+) connected to the wiring pattern 21 (+). The opening 24 from which the light is emitted is formed.

After etching as described above, the masking material can be removed by washing with an aqueous alkali solution such as an aqueous sodium hydroxide solution.
The wiring board from which the masking material 23 has been removed is shown in FIG.

  Next, a tin plating layer 18 is formed on the wiring board thus formed as shown in FIG. Since this tin plating layer is formed by an electroless plating method, it is formed on the surface of the wiring pattern and inner lead formed by etching.

  By forming the tin plating layer in this manner, the gold-tin eutectic compound is formed by the gold supplied from the bump electrodes 32 and 33 of the LED 30 and the tin supplied from the tin plating layer formed on the surface of the inner lead. By forming, the inner lead and the LED 30 can be firmly bonded.

The thickness of such a tin plating layer is usually in the range of 0.3 to 10 μm, preferably 0.5 to 10 μm.
After forming the tin plating layer as described above, the LED 30 is mounted. The LED 30 normally has gold bumps formed on the positive electrode and gold bumps formed on the negative electrode. Further, since tin exists on the surface of the inner lead, a gold-tin eutectic is formed, and the LEDs 30 are firmly and collectively bonded to the inner lead.

That is, in the present invention, after one LED 30 is inserted into each device hole 14, a plurality of LEDs 30 can be collectively bonded to the heat dissipating inner leads 22 formed in each device hole 14.

  After the LED 30 and the inner lead are electrically joined as described above, it is preferable to attach a reflection plate to the surface of the insulating substrate 10. Examples of the reflector used here include metal foils such as aluminum foil and copper foil, and the above-mentioned metal foil whose surface is insulated. Moreover, the adhesive agent used when sticking this metal foil can be used as an insulating layer. The thickness of the reflector used in this way is usually in the range of 10 to 100 μm, preferably 20 to 50 μm. The adhesive used here is preferably a thermosetting adhesive, and usually an epoxy resin adhesive, a polyimide resin adhesive, a thermosetting acrylic adhesive, or the like is used. The thickness of the adhesive layer is usually 5 to 50 μm, preferably 10 to 20 μm.

  After sticking the reflecting plate 36 to the back surface as described above, the light-emitting resin portion 38 is formed by filling the transparent resin from the opening 24 in which the heat dissipating inner leads of the device hole 14 are formed. Here, examples of the transparent resin to be used include an acrylic resin and an epoxy resin. The light emission resin portion 38 formed from such a resin can be diffused in a wide angle by raising the surface shape so as to be a dome shape. It is preferable to use a thermosetting resin as the resin forming the light-emitting resin portion 38 as well.

  When a blue diode or an ultraviolet diode is used, blue light or ultraviolet light can be converted into white light by, for example, blending a fluorescent agent with the light emitting resin portion 38.

As described above, since the LED 30 is housed in the device hole 14 and the tin plating layer 18 is formed in the light emitting module of the present invention, the heat generated from the LED 30 mounted in the device hole 14 The light is emitted through the wiring pattern 21 through the leads 22 (−) and 22 (+), and the heat energy of the device hole generated from the LED 30 disposed in the device hole 14 is reflected by the reflector 36 bonded to the bottom. It can be discharged through a metal sheet.

  Moreover, the light emitting module of the present invention does not join the LED 30 by wire bonding as in the conventional light emitting module, and is disposed in the device hole of the TAB tape type substrate by bonding using bumps formed on the LED. Since the plurality of LEDs 30 can be mounted on the heat dissipating inner leads by batch bonding, the bonding efficiency is high, and the light emitting module of the present invention can be easily manufactured.

That is, in the present invention, one LED is inserted into each of a large number of device holes, and a number of bonders corresponding to the number of device holes are brought into contact with the large number of device holes and LEDs into which the LEDs are thus inserted. Then, by applying heat while applying ultrasonic waves and further applying pressure as necessary, a large number of LEDs can be mounted by a single bonding operation. Therefore, the LED can be mounted very efficiently.

  In the optical module of the present invention, most of the light from the LED can be emitted from the light emitting resin portion 38. Therefore, the light emitting module of the present invention has the characteristics that it is very efficient and the temperature does not increase.

  Next, although the Example of this invention is shown and the wiring board and light emitting module of this invention are demonstrated in detail, this invention is not limited by these.

[Example 1]
A polyimide film with an adhesive layer having an adhesive layer made of a polyimide precursor on one surface of a polyimide film having a thickness of 75 μm was prepared.

This adhesive layer with the polyimide film, the diameter L ₃ to form a number of circular device hole of 0.5 mm.

On this polyimide film with an adhesive layer, an electrolytic copper foil having an average thickness of 35 μm was placed so that the mat surface of the electrolytic copper foil faces the adhesive layer, and pressed under heating to form a laminate. .
Next, a masking material was formed by using a photosensitive resin on the inner peripheral surface of the device hole layer and the electrolytic copper foil surface on which the wiring pattern was formed, and exposing and developing.

Thus, the laminated body which formed the masking material was immersed in the etching agent, the metal of the part in which the masking material was not formed was removed, and the masking material was removed by alkali washing.
After removing the masking material in this manner, electroless tin plating was performed to form a tin plating layer on the metal surface.

  Next, the LED 30 is inserted into the device hole 14, and a gold-tin eutectic is formed in the device hole 14 by means of ultrasonic heating using the bump electrode of the LED and the tin of the inner lead by batch bonding. Electrically fixed to the inner lead.

After fixing the LED in this manner, an aluminum foil having an insulating process on the front surface was attached to the back surface using an epoxy resin.
Further, the light emitting resin portion was formed by sealing with a thermosetting acrylic resin on the side where the inner lead was formed.

The power of about 1 W was supplied to the nine light emitting modules thus formed, and the amount of light from the light emitting module of the present invention and the temperature of the light emitting module were measured.
Nine commercially available LED elements were arranged, a light emitting module was formed in the same manner, and the amount of light and temperature were compared. The results are listed in the following table.

  According to the light emitting module of the present invention, heat is conducted also from the electrode leads, so the temperature of the light emitting module does not increase. Therefore, the light emitting module of the present invention has the characteristics that LEDs can be mounted at high density, the light emission amount per unit area is high, and the temperature rise is small compared to the light emission amount. Therefore, the light emitting module of the present invention can be used as a new third light source different from the incandescent lamps and fluorescent lamps conventionally used.

FIG. 1 is a view showing an example of a plane of a wiring board forming a light emitting module of the present invention. FIG. 2 is an enlarged view of FIG. 1 and is a plan view showing a state where the LEDs are mounted. 3 is a cross-sectional view taken along line XX in FIG. FIG. 4 is an enlarged cross-sectional view of a portion where one LED is mounted. FIG. 5 is a cross-sectional view of members showing an example of a manufacturing process of the light emitting module of the present invention.

Explanation of symbols

8 ... Sprocket hole 10 ... Insulating substrate 12 ... Adhesive layer 14 ... Device hole 18 ... Tin plating layer 20 ... Copper foil (electrolytic copper foil)
21 ... Wiring pattern 22 ... Heat dissipation inner lead 23 ... Masking material 24 ... Opening 30 ... Light emitting diode (LED)
32 ... Bump electrode 33 ... Bump electrode 36 ... Reflector (metal sheet)
38 ... Idemitsu resin part

Claims (9)

  A wiring pattern is formed on one surface of an insulating substrate having a large number of device holes, and a pair of heat dissipating inner leads are extended from the wiring pattern into each device hole. The electrode terminal of the mounted light emitting diode is electrically connected to the heat dissipating inner lead extending in the device hole, and at least part of the heat generated when the light emitting diode emits light is in the device hole. A light emitting module using a light emitting diode, characterized in that heat is exhausted to the outside through a wiring pattern from a heat dissipating inner lead that is extended to and electrically connected to the light emitting diode. 2. The light emitting module according to claim 1, wherein the insulating substrate is a polyimide film having an average thickness in the range of 50 to 300 [mu] m. 2. The wiring pattern and the heat dissipating inner lead are formed by etching a copper foil having an average thickness of 12 to 120 [mu] m adhered to a polyimide film with an adhesive layer. The light emitting module as described.   The light-emitting diodes inserted into the device holes are three types of light-emitting diodes of red (R), blue (B), and green (G), and the light-emitting diodes positioned in the adjacent vertical and horizontal directions The light emitting module according to claim 1, wherein the colors are not the same.   The light-emitting diode inserted in the device hole is a blue (B) light-emitting diode and / or an ultraviolet light-emitting diode, and a phosphor that converts light from the light-emitting diode into white is filled on the light-emitting diode. The light emitting module according to claim 1, wherein the light emitting module is provided.   2. The light emitting module according to claim 1, wherein the heat dissipating inner lead is in contact with 60% or more of the end portion where the terminal of the light emitting diode is formed.   2. The light emitting module according to claim 1, wherein a transparent resin is filled in a device hole in which the light emitting diode is mounted.   2. The light emitting module according to claim 1, wherein a reflector is disposed on the back side of the wiring pattern including the heat dissipating inner leads on which the light emitting diodes are mounted.   The light emitting diode and the heat dissipating inner lead are joined by a metal supplied from a metal bump formed on the light emitting diode side and a metal supplied from a plating layer formed on the surface of the heat dissipating inner lead. The light-emitting module according to claim 1.

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