JP5533183B2 - LED light source device and manufacturing method thereof - Google Patents

Description

  The present invention relates to an LED light source device using an LED chip and a manufacturing method thereof, and more particularly to an LED light source device and a manufacturing method of sandwiching the upper and lower sides of an LED chip with a substrate.

  Various LED light source devices have been proposed in order to meet demands for thinning and low cost in applications such as lighting devices arranged on the ceiling, wall surface, and the like. For example, an LED light source device in which a plurality of LED chips are flip-chip mounted on a flexible substrate has been proposed (for example, Patent Documents 1 and 2).

JP 2002-280613 A JP 2008-91459 A

The LED light source device in which a plurality of LED chips are flip-chip mounted on the flexible substrate of Patent Documents 1 and 2 can be manufactured with a structure that can reduce manufacturing time or be easily deformed by using the flexible substrate. Have the following problems.
When the flexible substrate is bent, the electrical characteristics of the LED chip change. This is because the bending stress is transmitted to the contact portion between the LED chip and the flexible substrate, and the contact area changes. Further, when the bending stress is strong, the LED chip may not shine due to disconnection of the contact portion.

Accordingly, an object of the present invention is to suppress a change in electrical characteristics due to bending of a flexible substrate, which is a problem of both Patent Documents 1 and 2.

In the LED light source device of the present invention, an LED chip having positive and negative electrodes formed on the same surface is placed on a flexible substrate having a wiring pattern so that the electrodes face the wiring pattern. A light-transmitting substrate that is less flexible than the flexible substrate is provided on the LED chip.
Moreover, it is preferable to provide an insulating adhesive between the flexible substrate and the translucent substrate.
The insulating adhesive preferably includes a first insulating adhesive provided on the flexible substrate side and a second insulating adhesive provided on the translucent substrate side.
Further, it is preferable that the second insulating adhesive is also provided on the upper surface of the LED chip.
The first insulating adhesive preferably has a hardness higher than that of the second insulating adhesive.
Moreover, there are a plurality of the light-transmitting substrates, and it is preferable that one or a plurality of the LED chips are arranged on one light-transmitting substrate.
Moreover, it is preferable that a fluorescent substance is arrange | positioned at the surface which the said translucent board | substrate opposes the surface to which the said LED chip was adhere | attached.
Moreover, it is preferable that the said translucent board | substrate contains the said fluorescent substance.
The first insulating adhesive has translucency with respect to the emission wavelength of the LED chip, has a linear expansion coefficient of 200 ppm / ° C. or less at 150 ° C. or less, and has a volume shrinkage due to curing. The material is preferably 3% or more and 15% or less.
In addition, it is preferable that the second insulating adhesive has a light-transmitting property with respect to the emission wavelength of the LED chip and has a volume shrinkage ratio of less than 1% due to curing.
The flexible substrate preferably has an aluminum foil as a conductive layer on an insulating film.

Moreover, the LED light source device of the present invention includes a step of disposing a first insulating adhesive on a flexible substrate having a wiring pattern;
A step of disposing an LED chip having positive and negative electrodes formed on the same surface on the first insulating adhesive;
Applying a load to the LED chip, electrically connecting the electrode and the wiring pattern, and heating and curing the first insulating adhesive;
The method includes a step of adhering a translucent substrate on the LED chip using a second insulating adhesive.

  In this invention, the change of the electrical property by the bending of the flexible substrate of a LED light source device can be suppressed.

It is a schematic sectional drawing for demonstrating one Embodiment of the LED light source device of this invention. It is the upper side figure and sectional drawing of a flexible substrate which has a wiring pattern of this invention. It is the upper side figure and sectional drawing of the LED chip of this invention. It is a schematic sectional drawing for demonstrating one Embodiment of the LED light source device of this invention. It is a schematic top view for demonstrating one Embodiment of the LED light source device of this invention. It is a schematic sectional drawing for demonstrating one Embodiment of the LED light source device of this invention. It is drawing for demonstrating the manufacturing method of the LED light source device of this invention. It is a schematic sectional drawing for demonstrating the method of connecting the LED light source device of this invention to an external power supply. It is the schematic top view and partial enlarged view for describing one Embodiment of the LED light source device of this invention. It is a schematic top view for demonstrating one Embodiment of the LED light source device of this invention.

  A mode for carrying out the present invention will be described with reference to the drawings. However, the form shown below is an example, does not limit the present invention, and the present invention is not limited to the dimensions, materials, shapes, relative arrangements, and the like of the components described. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. In order to simplify the description, the same constituent elements are denoted by the same reference numerals, and a part of the description is omitted.

FIG. 1 shows a drawing for explaining an example of the LED light source device of the present invention. FIG. 1 is a partial cross-sectional view of an LED light source device of the present invention. 2 is a view showing a flexible substrate on which a wiring pattern used in the present invention is formed. FIG. 2 (a) is a top view and FIG. 2 (b) is a cross-sectional view. FIG. 3 is a drawing showing an LED chip used in the present invention, FIG. 3 (a) is a top view, and FIG. 3 (b) is a cross-sectional view.
As shown in FIG. 1, the LED light source device of the present invention has an LED chip 12 mounted on a flexible substrate 10 having a wiring pattern 11. A translucent substrate 13 is provided on the LED chip 12. The LED chip has positive and negative electrodes 16 formed on the same surface, and is placed on a wiring pattern 11 provided on the flexible substrate 10 face down. Further, a first insulating adhesive 14 and a second insulating adhesive 15 are provided between the flexible substrate 10 having the wiring pattern 11 and the translucent substrate 13.
Further, in this specification, the LED chip is assumed to have positive and negative electrodes formed on the same surface, and the face-down is the direction in which the electrodes are placed so as to face the wiring pattern.

Each structure of the present invention will be described.
(Flexible board with wiring pattern)
A flexible substrate having a wiring pattern is a printed substrate that is flexible and can be deformed. This is a structure in which an insulating film with a thickness of 10 μm to 300 μm is used as a base material, an adhesive layer is formed thereon, and a wiring pattern with a thickness of about 10 μm to 50 μm is formed thereon as a conductive layer. Suitable for Generally, it is called a flexible substrate, a flexible printed substrate, or the like.
Examples of the insulating film material include resin films such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyetherimide (PEI), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), and polyimide (PI). Of these, PET and PEN, which are inexpensive, are preferable. In addition, an insulating film material having a higher light reflectivity with respect to visible light, such as a material obtained by applying or blending a light reflecting material or a material obtained by finely foaming an insulating film material, is more preferable than a transparent resin film. . Specific examples include Lef White (registered trademark) manufactured by Kimoto Co., Ltd. and MCPET manufactured by Furukawa Electric Co., Ltd.
For the adhesive layer, an adhesive that can withstand the assembly process is used, such as an epoxy adhesive, a urethane adhesive, or a silicone adhesive.
The wiring pattern material may be copper foil or aluminum foil, but aluminum foil or aluminum alloy foil having high light reflectivity with respect to visible light is preferable. Since the aluminum foil is excellent in light reflectivity for visible light in addition to the conductivity required as a wiring circuit, the LED light source device can be made in a simple structure. From the viewpoint of mountability of the LED chip, it is preferable to temper the aluminum foil or the aluminum alloy foil. A hard material (H material) that has been cold worked and hardened is more preferable than a soft material (O material) that has become the softest state by annealing. Further, the Brinell hardness HBS is preferably about 30 to 150, more preferably about 50 to 100 under the condition of (HBS10 / 500).
Moreover, it is preferable to use an aluminum foil made by a construction method in which a plurality of low-priced materials are rolled and rolled. The aluminum foil made by this method has a matte or poppy surface with no gloss and a bright or glossy surface. Of these, a glossy bright surface or gloss surface is preferably used as a surface, that is, a surface on which an LED chip described later is mounted, so that light reflectivity can be improved.

  FIG. 2 illustrates a flexible substrate having a wiring pattern used in the present invention. As an example of a flexible substrate having a wiring pattern used in the present invention, an adhesive layer of urethane adhesive is formed on a PEN film 100 μm that has been improved in light reflectivity by blending a light reflecting material such as titanium oxide. In addition, a hard aluminum foil having a thickness of 20 μm is formed thereon. The size of the flexible substrate is 2 cm wide and 60 cm long. In order to process the wiring pattern for lighting the LED chip, a total of 19 lines were removed from the aluminum foil with a width of 200 μm and a pitch of 3 cm in the short direction of the flexible substrate. The removed portion of the aluminum foil is referred to as a space portion 17. As a method for forming the space portion, gravure printing, wet etching, cutting with a cutter such as a dicer, laser cutting, or the like is possible. Furthermore, in order to ensure the insulation of the space portion, it is conceivable to provide an insulating member in the space portion. At that time, light extraction efficiency can be improved by using a light reflecting material blended into the adhesive, such as PSR-4000LEW manufactured by Taiyo Ink Manufacturing Co., Ltd. and LPS-8630W and LPS-8433W manufactured by Shin-Etsu Chemical Co., Ltd. It is also possible to improve further.

  The shape of the flexible substrate is not limited to a rectangular shape, and can respond to various geometrical requirements such as a circle and a polygon required for the LED light source device. In addition, the wiring pattern is not limited to a series circuit as long as a plurality of LEDs can be turned on, but is not limited to a series circuit, a circuit that combines both, etc. It is possible to respond.

(Insulating adhesive)
Further, an insulating adhesive is provided between the flexible substrate having the wiring pattern and the translucent substrate. The LED chip is usually connected to the flexible substrate by a bonding method using a bonding material such as a solder material, a conductive adhesive, or an ultrasonic bonding apparatus. When these methods are used, there are the following problems. In the case of joining using a solder material, the flexible substrate is required to have a heat resistance of at least 200 ° C. or more, so that the flexible substrate becomes expensive. Further, in the case of bonding using a conductive adhesive, it is difficult to apply the conductive adhesive in a minute amount, and therefore it is necessary to use a large LED chip, which increases the cost of the LED chip. In addition, since the bonding method using the ultrasonic bonding apparatus cannot mount a plurality of LED chips at a time, the production speed is slow. In the present invention, since the LED chip is sandwiched between a flexible substrate having a wiring pattern and a light-transmitting substrate and bonded with an insulating adhesive, the price can be reduced.
The insulating adhesive is preferably transparent with respect to the emission wavelength of the LED chip, and an epoxy-based adhesive, a silicone-based adhesive, and the like are conceivable.
The insulating adhesive may be a liquid type or a sheet type. The LPS-1000-5000 series manufactured by Shin-Etsu Chemical Co., Ltd. can be considered for the liquid type, and the LPS-AF series manufactured by Shin-Etsu Chemical Co., Ltd. whose main component is phenyl silicone can be considered for the sheet type. Since the handling and thickness management are easy, the sheet type is preferable.
It is also possible to add optical properties such as wavelength conversion and light dispersion by blending a phosphor or a light dispersion material into the insulating adhesive.

(First insulating adhesive)
Among the insulating adhesives, the one provided on the flexible substrate side is the first insulating adhesive. The first insulating adhesive is preferably transparent to the emission wavelength of the LED chip, and an epoxy adhesive, a silicone adhesive, and the like are conceivable. Among these, a silicone adhesive whose main component is excellent in light resistance is preferable.
The volume shrinkage due to curing of the first insulating adhesive is preferably 3% or more and 15% or less, and more preferably 5% or more and 10% or less. When there is shrinkage due to this degree of curing, moderate shrinkage stress remains at the contact portion of the flexible substrate having the LED chip and the wiring pattern, so that high reliability can be achieved.
During the operation of the LED light source device of the present invention, the LED chip may generate heat up to a temperature of about 150 ° C., and the adjacent first insulating adhesive may have the same temperature. When the temperature is increased, the first insulating adhesive is thermally expanded, the contact area of the contact portion of the flexible substrate having the LED chip and the wiring pattern is reduced, and the electrical characteristics of the LED chip are deteriorated. Furthermore, when thermal expansion proceeds, the LED chip may break and the LED chip may not shine. However, if a first insulating adhesive having a relatively small linear expansion coefficient is selected, this problem can be prevented and it can withstand practical temperature changes. Specifically, the linear expansion coefficient at a temperature of 150 ° C. or lower is preferably 200 ppm / ° C. or lower, more preferably 100 ppm / ° C. or lower.
The thickness of the first insulating adhesive is preferably 20% or more and 100% or less, more preferably 40% or more and 80% or less with respect to the thickness of the LED chip.

(LED chip)
The LED chip can emit light by applying a predetermined voltage. The emission color of the LED can be selected from visible light, ultraviolet light, infrared light, and the like. In the case of visible light, the emission color is not limited, and any of a green LED, a red LED, and a blue LED can be used. Furthermore, a white LED chip in which a phosphor is applied to a blue LED chip can also be used.
Further, the semiconductor material is not particularly limited, and any compound such as III-V group or II-VI group may be used.
The LED chip used in the present invention will be described with reference to FIG.
The LED chip used in the present invention is preferably provided with a p-electrode and an n-electrode on the same surface, and both electrodes are provided with a current-carrying projection called a bump. It is preferable that at least a pair of bump electrodes is provided. As the bump, a wire bump using an Au wire or a plating bump made of a metal material such as Au or Cu can be considered. The bump size is, for example, a substantially cylindrical shape or a substantially conical shape with a diameter of 20 μm to 100 μm and a height of 5 μm to 50 μm.
The distance between the pair of bump electrodes is preferably set to be wider than the space portion of the wiring pattern provided on the flexible substrate. Specifically, when the width of the space portion is 200 μm, the distance between the bumps is preferably 400 μm or more.
In addition, the drive current of one LED chip is preferably about 20 mA from the viewpoint of heat dissipation. When the drive current is high, the current density of the active layer increases and the light emission efficiency deteriorates. Moreover, when it is low, the LED chip cannot be used effectively. Therefore, the current density is preferably 0.3 A / mm ² or more and 1 A / mm ² or less, and more preferably 0.65 A / mm ² or more and 1 A / mm ² or less. Thus, the active layer area of the LED chip is preferably 0.02 mm ² or more 0.07 mm ² or less, more preferably 0.02 mm ² or more 0.03 mm ² or less.
Since the LED chip becomes more expensive as the chip area becomes larger, the outer size of the LED chip is preferably as small as possible within the range where the distance between the bumps and the active layer area can be satisfied and the LED chip can be manufactured. Therefore, it is preferably a rectangle as shown in FIG. 3, and more preferably a rectangle having a ratio of the long side to the short side of about 5: 1.

  In the present invention, the LED chip is placed face down on a flexible substrate having a wiring pattern. Thereby, even when a plurality of LED chips are used, it is possible to reliably energize. When LED chips are mounted on a substrate with small flexibility, contact failure may occur in some LED chips within the substrate surface. By using a flexible substrate, the LED chip and the substrate can be securely connected. Can be contacted.

(Second insulating adhesive)
What is provided closer to the translucent substrate than the first insulating adhesive is referred to as a second insulating adhesive. By using two types of adhesives, the LED chip is fixed to the flexible substrate using the first insulating adhesive, and then the translucent substrate is provided using the second insulating adhesive. Therefore, the mounting accuracy of the LED chip can be increased. In addition, since the translucent substrate can be provided after confirming the position of the LED chip, the translucent substrate can be provided at an arbitrary position in consideration of light distribution.
Moreover, it is preferable that the second insulating adhesive is also provided on the upper surface of the LED chip.
By providing the second insulative adhesive on the upper surface of the LED chip, the second insulative adhesive acts as a buffer material, and the mechanical load on the LED chip can be reduced.
Similar to the first insulating adhesive, the second insulating adhesive is preferably a silicone adhesive that is transparent to the light emission wavelength of the LED chip and has good light resistance. Furthermore, the volume shrinkage due to curing is preferably less than 1%, and more preferably 0.5% or less. Moreover, the thing with small hardness is preferable, and what has a dimethyl silicone as a main component specifically, is preferable. When the shrinkage due to the curing of the second insulating adhesive is less than 1%, the translucent substrate can be laminated without applying unnecessary force to the LED chip during manufacturing.
The second insulating adhesive is used for laminating a light-transmitting substrate that is less flexible than the flexible substrate on the flexible substrate on which the LED chip is mounted.
If the second insulating adhesive is greatly contracted by curing and has a high hardness, the flexible substrate may be displaced from its original position during curing. Similar to the bending of the flexible substrate, this displacement causes a change in the electrical characteristics of the LED chip and disconnection of the contact portion, and the LED chip may not shine.
It is also possible to add a phosphor or a light dispersion material to the second insulating adhesive to add optical characteristics such as wavelength conversion and light dispersion.

Moreover, it is preferable that the first insulating adhesive has a hardness higher than that of the second insulating adhesive. The adhesive part of the flexible substrate having the LED chip and the wiring pattern is strengthened with the first insulating adhesive having a high hardness, and the translucent substrate is placed on the flexible substrate with the second insulating adhesive having a low hardness. This is because a structure that does not apply a mechanical load to the LED chip can be realized by bonding to the LED chip.
In addition, since the first insulating adhesive fixes the LED chip, a heat-resistant adhesive is used in consideration of heat generation, and the second insulating adhesive is used with a small shrinkage due to curing. The load due to the provision of the translucent substrate on the LED chip can be reduced, the flexible substrate and the translucent substrate can be securely bonded, and the LED light source device can be driven stably.

(Translucent substrate)
In the present invention, a light-transmitting substrate that is less flexible than a flexible substrate is used as the substrate disposed on the LED chip. By providing a light-transmitting substrate with low flexibility on the LED chip, the flexible substrate is less likely to bend around the LED chip, so that the contact area at the contact portion between the LED chip and the flexible substrate does not change. Therefore, even when the flexible substrate is bent, the electrical characteristics of the LED chip do not change, and the characteristics of the LED light source device can be stabilized.
Moreover, by using a translucent substrate, the apparent brightness of the LED chip can be reduced and the glare of the LED light source device can be suppressed. When the LED light source device is used for illumination and the light emitting surface is in the field of view, dazzling may give an unpleasant feeling when the luminance is high. Since the LED chip is small and bright, the brightness is high. Even if a phosphor layer is provided so as to cover the LED chip, the same is true with respect to glare. By providing the light-transmitting substrate on the LED chip, the LED chip can be seen through the light-transmitting substrate. Therefore, the light scattering effect on the surface or the surface of the light-transmitting substrate can reduce the glare of the LED light source device. Can be suppressed.

The translucent board | substrate of this invention refers to the board | substrate which has translucency with respect to the light emission wavelength of the LED chip to be used. When the substrate thickness is 3 mm, the light transmittance of the light emission wavelength of the LED chip is preferably 80% or more, and more preferably 95% or more.
The translucent substrate is made of a material or thickness that is less flexible than the flexible substrate. The flexibility can be quantified by the minimum bending radius in a state where the substrate is bent as much as possible without causing breakage or cracks in the substrate. Further, a radius that does not include the thickness of the substrate among the bending radii is referred to as an inner bending radius. It is preferable that the minimum inner bending radius of the translucent substrate is 50 mm or more.
As a translucent substrate, glass materials such as alkali-free glass, soda-lime glass, lead glass, borosilicate glass, polycarbonate (PC), polymethyl methacrylate (PMMA), PET, polypropylene (PP), polystyrene (PS), Transparent resin materials such as polyvinyl chloride (PVC) and acrylonitrile / butadiene / styrene (ABS) can be used. Among them, a glass material excellent in light resistance and moisture resistance is suitable as a protective material for the LED chip.

  As shown in FIGS. 4 and 5, it is preferable that a plurality of light-transmitting substrates are provided for one flexible substrate. As shown in FIG. 4, one LED chip may be arranged on one light-transmitting substrate, or a plurality of LED chips are arranged on one light-transmitting substrate as shown in FIG. May be. Since a plurality of light-transmitting substrates are provided for one flexible substrate, when the LED light source device is bent, bending stress is generated between a portion without the light-transmitting substrate and between the plurality of light-transmitting substrates. concentrate. Further, since the contact area between the LED chip and the flexible substrate does not change, the electrical characteristics of the LED chip do not change. That is, the flexible substrate can be freely bent while maintaining the electrical characteristics of the LED chip. Further, the light source can be made highly efficient due to the effect of extracting light from the side surface of the translucent substrate.

Further, it is possible to control light distribution by providing an optical pattern on the surface of the light-transmitting substrate. Specifically, it is conceivable to use a lens shape when collecting light in a specific direction and a rough surface shape when it is desired to obtain uniform brightness in all directions on the light exit surface side. In addition, by placing an inorganic light dispersion material such as titanium oxide, silicon oxide, alumina, zinc oxide, glass fine powder, or an organic light dispersion material such as acrylic or polystyrene on the surface or inside of the light transmissive substrate, The brightness in the substrate can be made more uniform.

In addition, as shown in FIG. 6, the emission wavelength can be adjusted by arranging a phosphor on or in the surface of the translucent substrate.
As shown in FIG. 6 (a), the translucent substrate may have the phosphor 18 disposed on the surface facing the surface to which the LED chip is bonded, or as shown in FIG. 6 (b). A translucent substrate 13b containing may be used. For example, a nitride phosphor or an oxynitride phosphor mainly activated by a lanthanoid element such as Eu or Ce can be used. More specifically, (a) Eu-activated α or β sialon type phosphor, various alkaline earth metal nitride silicates, various alkaline earth metal aluminum silicon nitrides (eg, CaSiAlN ₃ : Eu, SrAlSi ₄ N ₇ : Eu), (b) lanthanoid elements such as Eu, alkaline earth metal halogenapatites mainly activated by transition metal elements such as Mn, alkaline earth metal halosilicates, alkaline earth metal silicates, Alkaline earth metal borate, alkaline earth metal aluminate, alkaline earth metal sulfide, alkaline earth metal thiogallate, alkaline earth metal silicon nitride, germanate, (c) lanthanoid elements such as Ce Mainly activated rare earth aluminate, rare earth silicate, alkaline earth metal rare earth silicate, (d It is preferably at least one selected from organic and organic complexes mainly activated by a lanthanoid element such as Eu. A YAG phosphor that is a rare earth aluminate phosphor mainly activated by a lanthanoid element such as Ce is preferable. YAG-based phosphors include Y ₃ Al ₅ O ₁₂ : Ce, (Y _0.8 Gd _0.2 ) ₃ Al ₅ O ₁₂ : Ce, Y ₃ (Al _0.8 Ga _0.2 ) ₅ O ₁₂ : Ce , (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ . Further, there are Tb ₃ Al ₅ O ₁₂ : Ce, Lu ₃ Al ₅ O ₁₂ : Ce, etc. in which a part or all of Y is substituted with Tb, Lu, or the like. When white light is required, it can be adjusted by a combination of a blue LED chip and a translucent substrate on which a yellow phosphor such as YAG is arranged. White illumination can be easily obtained.
The light emitting area of the translucent substrate is preferably 10 to 10,000 times, more preferably 100 to 1000 times the light emitting area of the LED chip. Here, the light emitting area is the surface area of the entire surface not facing the flexible substrate. The light-transmitting substrate can be handled as a light emitter due to the light scattering effect in or on the surface of the light-transmitting substrate. Therefore, when the light emitting area of the light-transmitting substrate is increased, luminance is reduced and glare is suppressed. On the other hand, if the size is increased unnecessarily, the cost of parts increases.

  Further, the insulating adhesive is not limited to the form provided over the entire LED chip or wiring pattern as shown in FIG. The insulating adhesive may be provided on at least the LED chip and bonded to the translucent substrate. Moreover, it is not provided on the LED chip, but may be filled only between the other flexible substrate and the translucent substrate.

Next, the manufacturing method of the LED light source device of this invention is demonstrated, referring FIG. In the manufacturing method of the present invention, the LED chip and the flexible substrate having the wiring pattern are electrically connected to each other, and both are fixed by the first insulating adhesive. Further, since the light-transmitting substrate is laminated with the second insulating adhesive and the LED chip is protected, low-cost assembly is possible.
In the manufacturing method shown in FIG. 7, the LED light source device of FIG. 4 can be obtained.
First, as shown in FIG. 7A, a conductive layer 11 for forming a wiring pattern on the flexible substrate 10 is provided.
Subsequently, as shown in FIG. 7B, the conductive layer 11 is patterned to provide a space portion 17, and the wiring pattern 11 is provided on the flexible substrate 10.
Next, as shown in FIG. 7C, a sheet-like first insulating adhesive 14 is disposed. At this time, the first insulating adhesive is provided so as to cover the LED chip placement planned position. Moreover, it is preferable to provide a 1st insulating adhesive so that a space part may be coat | covered. In the LED light source device shown in FIG. 4, a plurality of first insulating adhesives are arranged on a flexible substrate in order to arrange a plurality of translucent substrates. The first insulating adhesive is arranged in an area smaller than that of the flexible substrate, and the wiring pattern and the space portion are partially exposed. The first insulating adhesive can be freely arranged in consideration of the size of the translucent substrate, the position where it is arranged, and the like.
Next, as shown in FIG. 7D, the LED chip 12 is temporarily arranged. At this time, if the tack property of the first insulating adhesive 14 is used, temporary arrangement becomes easy.
Next, as shown in FIG. 7E, the LED chip is subjected to weighting and heat treatment. A load is applied using a press machine, and the electrodes of the LED chip are electrically connected to the wiring pattern provided on the flexible substrate. The direction of weighting is as shown by the arrows in the figure. At this time, the first insulating adhesive is cured by heating. Due to the shrinkage caused by the curing that occurs during curing and the shrinkage caused by the thermal change that occurs when the heating temperature returns to room temperature, the first insulating adhesive is moderately contracted at the contact portion between the LED chip and the flexible substrate. It cures with the stress remaining.
Next, as shown in FIG. 7F, a second insulating adhesive 15 is applied.
Next, as shown in FIG. 7G, the translucent substrate 13 is placed, and heat treatment is performed to cure the second insulating adhesive. As described above, the LED light source device of the present invention can be obtained.

Furthermore, efficient production can be considered by a roll-to-roll system.
For example, there is a method in which a wiring pattern is provided on a long flexible substrate that is wound in a roll shape of about several hundreds of meters, an LED chip and a translucent substrate are mounted, and then wound around a roll again. If flexible substrates separated individually are used, it takes time and labor to transport each substrate from one process to the next. In addition, since the carry-in / carry-out unit is provided in each manufacturing apparatus, the scale of the apparatus increases. When this roll-to-roll method is adopted, the substrate flows continuously between the apparatuses. That is, the manufacturing apparatuses are connected to each other, and the labor and apparatus involved in the conveyance can be saved greatly. As a result, the manufacturing cost can be reduced by orders of magnitude compared to the conventional case.

Next, the connection method to the power cable for supplying electric power from the external power supply device to the LED light source device of the present invention will be described. When an aluminum foil is used for the wiring pattern, the aluminum surface tends to form an oxide film, so that there is a problem that electric resistance increases. Then, when connecting the LED light source device of this invention with a power supply cable, as shown in FIG. 9, it is possible to connect an aluminum foil and a power supply cable by ultrasonic bonding or resistance welding. Since these methods can remove the oxide film on the aluminum surface simultaneously with the connection, the assembly can be efficiently performed. Further, since the heat load on the flexible substrate is small, a low-cost package member with low heat resistance can be selected.

  Further, as shown in FIG. 8, it is also conceivable to connect aluminum electrode terminals provided with an oxidation resistant film in part or in advance by ultrasonic welding or resistance welding. The oxidation resistant film is a film formed by depositing a metal film such as Au, Sn, or Ni by a known method such as plating or sputtering. In this case, since the power cable is connected to the portion provided with the oxidation resistant film, there is no factor that hinders electrical conductivity. Therefore, a general electrical connector that can be removed can be used.

The Example of the LED light source device of this invention is shown below.
Example 1
FIG. 9A shows a line-shaped LED light source device. In the flexible substrate, a wiring pattern provided with a space portion 17 is provided with an aluminum foil on an insulating film made of PEN and having a thickness of 100 μm as shown in FIG. 9B. The size of the flexible substrate is 2 cm wide and 60 cm long. On the flexible substrate, a translucent substrate 13 made of non-alkali glass printed with a 200 μm-thick silicone adhesive containing a YAG-based phosphor is arranged, the size of which is 5 mm square, The thickness is 0.7mm. 19 translucent substrates 13 are arranged at a pitch of 3 cm.
FIG. 9B is an enlarged view near the translucent substrate 13. Under the translucent substrate, three blue LED chips are mounted in parallel. Although not shown, between the translucent substrate and the flexible substrate, LPS-AF series manufactured by Shin-Etsu Chemical Co., Ltd. as a first insulating adhesive in order from the flexible substrate side is 50 μm, As the second insulating adhesive, LPS-1000 to 5000 series manufactured by Shin-Etsu Chemical Co., Ltd. is provided with 200 μm.
Since one LED chip is designed to be energized with 20 mA and about 3 V, the LED light source device is energized with 60 mA and about 57 V. The light output of one light emitter is about 15 lm, and a total light output of about 285 lm can be obtained.

(Example 2)
Example 2 is a planar light source in which the line-shaped LED light source device of Example 1 is attached to a base 33 made of a galvanized steel sheet painted white as shown in FIG. The size of the base 33 is 70 cm square, and 19 line-shaped LED light source devices of Example 1 are arranged at a pitch of 3 cm. Therefore, a total light output of 5415 lm can be obtained.
It is also possible to adjust the light distribution by sticking an optical film on the LED light source device or to make the luminance uniform.

(Example 3)
In this embodiment, as shown in FIG. 1, a single translucent substrate is provided on a flexible substrate.
Specifically, a translucent substrate having a width of 2 cm and a length of 60 cm is used, and a first insulating adhesive and a second insulating adhesive having a size corresponding to the translucent substrate are provided. Other configurations are substantially the same as those in the first embodiment.
In this example, the light emitting area is increased as compared with Example 1, which is preferable in terms of alleviating glare.

Example 4
In this embodiment, as shown in FIG. 6B, a translucent substrate containing a phosphor is used.
Specifically, a translucent substrate 13b having a thickness of 700 μm made of a silicone resin molded body in which a YAG phosphor is blended is used. Other configurations are substantially the same as those in the first embodiment.
According to the present embodiment, a white LED light source device can be obtained and can be used for various lighting fixtures.

The LED light source device of the present invention can be used in a wide range of displays, indicators, squid, sanma, and other fish-collecting lights, in addition to lighting fixtures and vehicle-mounted lighting.

10: Flexible substrate 11: Wiring pattern (conductive layer)
11b: Connection portion 12: LED chip 13: Translucent substrate 13b: Phosphor-containing translucent substrate 14: First insulating adhesive 15: Second insulating adhesive 16: Bump electrode 17: Space portion 18 : Phosphor 20: Substrate 21: First semiconductor layer 22: Second semiconductor layer 23: Electrode 30: Power cable 31: Electrode terminal 32: Oxidation-resistant film 33: Base 34: Electrical connector

Claims (13)

On a flexible substrate having a wiring pattern, an LED chip having positive and negative electrodes formed on the same surface is placed so that the electrode faces the wiring pattern,
Provided with a light-transmitting substrate that is less flexible than the flexible substrate on the LED chip,
An insulating adhesive is provided between the flexible substrate and the translucent substrate that sandwich the LED chip,
The insulating adhesive includes a first insulating adhesive provided on the flexible substrate side and a second insulating adhesive provided on the translucent substrate side and having a hardness lower than that of the first insulating adhesive. LED light source device and having the insulating adhesive agent. The LED chip top surface, LED light source device according to claim 1 having the insulating adhesive. 3. The LED light source device according to claim 1, wherein there are a plurality of the light transmissive substrates, and one or a plurality of the LED chips are arranged on one light transmissive substrate. The LED light source device according to any one of claims 1 to 3 , wherein the translucent substrate has a phosphor disposed on a surface facing a surface to which the LED chip is bonded. The translucent substrate LED light source device according to any one of claims 1 to 4 containing the phosphor. The first insulating adhesive has translucency with respect to the light emission wavelength of the LED chip, has a linear expansion coefficient of 200 ppm / ° C. or less at 150 ° C. or less, and a volume shrinkage ratio by curing of 3%. LED light source device according to any one of claims 1 to 5 which is a material of 15% or less. The said 2nd insulating adhesive agent has translucency with respect to the light emission wavelength of the said LED chip, and the volumetric shrinkage rate by hardening is less than 1%, The any one of Claims 1 thru | or 6 LED light source device. The flexible substrate, LED light source device according to any one of claims 1 to 7 are those having an aluminum foil as a conductive layer on an insulating film. Disposing a first insulating adhesive on a flexible substrate having a wiring pattern; disposing an LED chip having positive and negative electrodes formed on the same surface on the first insulating adhesive; ,
Applying a load to the LED chip, electrically connecting the electrode and the wiring pattern, and heating and curing the first insulating adhesive;
The manufacturing method of the LED light source device which comprises the process of adhere | attaching a translucent board | substrate using a 2nd insulating adhesive agent on the said LED chip. The method of manufacturing an LED light source device according to claim 9, wherein the second insulating adhesive has a lower hardness than the first insulating adhesive. 11. The method of manufacturing an LED light source device according to claim 9, wherein there are a plurality of the light-transmitting substrates, and one light-transmitting substrate is disposed for one or a plurality of the LED chips. The manufacturing method of the LED light source device of any one of Claims 9 thru | or 11 which arrange | positions a fluorescent substance in the surface facing the surface to which the said LED chip was adhere | attached. The manufacturing method of the LED light source device of any one of Claims 9 thru | or 12 which arrange | positions the said translucent board | substrate containing the said fluorescent substance.

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