KR20110135806A - Light emitting diode substrate and method for manufacturing the same - Google Patents

Abstract

PURPOSE: A light-emitting device substrate and a manufacturing process thereof are provided to improve productivity by rapidly forming a water repellent type circularity film which is installed in around a light-emitting device at a time. CONSTITUTION: A flexographic printing plate in which the ink maintenance part of a desired pattern is formed in the surface is prepared. Water repellent ink which contains fluorine maintains is maintained in the ink maintenance part of the flexographic printing plate. A substrate(10) adheres closely to the flexographic printing plate. The water repellent ink is transferred in the prescribed part around a predetermined location in which a light-emitting device is arranged of the substrate. The solvent of the water repellent ink is evaporated after being transferred and a water repellent type circularity film is formed on the surface of the substrate. An encapsulation part(4) of a dome type which cavers the light-emitting device is formed in the inner side of the water repellent type circularity film.

Description

LIGHT EMITTING DIODE SUBSTRATE AND METHOD FOR MANUFACTURING THE SAME

The present invention relates to a light emitting device substrate in which a light emitting device mounted on a substrate is sealed with a resin, and a method of manufacturing the same.

Conventionally, in order to reduce energy of a device, a backlight using a light emitting element such as a light emitting diode (LED) as a light source of a liquid crystal display panel (hereinafter, an LCD panel) such as a liquid crystal TV, a liquid crystal display, a liquid crystal monitor, and the like (flat surface) Light emitting device) is used (for example, refer patent document 1).

With the recent increase in size of liquid crystal TVs and the like, the backlights are arranged by arranging a plurality of light emitting elements (bare chips) on a flat substrate, and electrically connecting these light emitting elements using wire bonding or the like. The above is sealed with resin, and it is increasing to use in combination multiple or vertically what unitized or modularized it as "light emitting element substrate", such as an LED substrate.

In the process of manufacturing the light emitting device substrate, when sealing the light emitting devices disposed on the substrate with resin to form a sealing part, a sealing resin is supplied dropwise (porting) using a syringe, a dispenser, and the like, and the sealing is performed. In order to give the lens a lens effect for guiding light upwards, the outer shape of the sealing resin is formed into a dome shape such as a shield shape or an almost hemispherical shape (see Patent Document 2).

In addition, before dropping the sealing resin, a liquid-repellent ink having water-repellent, oil-repellent, or the like in advance around each of the light emitting elements disposed on the substrate is formed by using the dispenser or the like. It is apply | coated to the strip | belt shape without a deletion in the circumferential direction, such as an elliptical shape and a rectangular shape with a round angle, and it dries to form a liquid-repellent film (refer patent document 3).

When the sealing resin is added dropwise, the resin for sealing is formed in the dome shape as above on the inner substrate (on the light emitting element) by using the liquid-repelling action of the annular coating as a hill or a dike blocking the sealing resin. It raises (refer patent document 4).

Japanese Laid-Open Patent Publication No. 2007-65414 Japanese Laid-Open Patent Publication No. 2008-34443 Japanese Laid-Open Patent Publication No. 2008-41968 Japanese Unexamined Patent Publication No. 2010-3994

However, the demand for LCD panel backlights is rapidly increasing as the use range of LCD panels is expanded and enlarged, and the light emitting device substrates used for the backlights are urgently improved in productivity and cost reduction.

However, as described above, in the manufacture of a conventional light emitting device substrate, since the liquid-repellent annular film provided around the light emitting device is formed one by one by a dispenser or the like, the efficiency of the annular film forming process does not increase and the improvement is desired. .

This invention is made in view of such a situation, Comprising: It aims at providing the light emitting element substrate which can improve the productivity by forming the liquid-repellent annular film provided around a light emitting element at once, and this manufacturing method.

In order to achieve the above object, the present invention provides a substrate, a light emitting element disposed on the substrate, a liquid-repellent annular film formed by flexographic printing on the substrate, and disposed around the light emitting element; The luminous element substrate provided with the dome-shaped sealing part formed in the state which coat | covered the said light emitting element by dripping sealing resin from the upper side of a film inside is made into 1st summary.

The present invention also provides a process for preparing a flexographic printing plate having an ink holding portion having a predetermined pattern on its surface, a step of holding a fluorine-containing liquid repellent ink on the ink holding portion of the flexographic printing plate, and a substrate on the flexo. In close contact with the printing plate, transferring the liquid repellent ink from the ink holding part of the flexographic printing plate to a predetermined portion around a predetermined position at which the light emitting element on the substrate is to be placed; and evaporating the solvent of the liquid repellent ink after the transfer. Forming a liquid-repellent annular coating on the surface of the substrate; and placing a light emitting element at the position on the substrate and electrically connecting the electrode to the electrode of the substrate, for sealing a predetermined amount from above the light emitting element. Light-emitting including the process of dripping resin and forming the dome-shaped sealing part which covers the said light emitting element inside the said cyclic film. The manufacturing method of an element substrate is set as 2nd summary.

That is, the present inventor has made intensive studies to solve the above problems, and as a result, uses a liquid repellent ink having water repellency, oil repellency and the like, and forms a thin film-shaped annular film on the surface of the substrate by flexographic printing. By discovering that the process efficiency of the said annular film formation process in the manufacturing process of a light emitting element board | substrate can be improved significantly, the present invention was reached.

This invention is made | formed based on the above viewpoints, The light emitting element substrate of this invention is provided with the liquid-repellent annular film formed by flexographic printing around the light emitting element arrange | positioned on the board | substrate. Therefore, the light emitting element substrate is formed (coated) with all of the annular coatings required for the formation of the dome-shaped sealing portion made of a sealing resin at once, and significantly shortens the time required for the processing, as compared with the case where a dispenser or the like is conventionally used. You can. Further, the annular coating is thinner and more uniform than the coating formed using the dispenser or the like, and the amount of liquid repellent ink used therein is also reduced. Therefore, the light emitting element substrate of the present invention can be formed efficiently and inexpensively.

The light emitting element substrate having the film thickness of the annular coating having a thickness of 1 nm to 1000 nm can suppress the amount of the liquid repellent ink while maintaining the function of preventing the sealing resin from leaking out of the annular coating.

Moreover, according to the manufacturing method of the light emitting element board | substrate of this invention, each process for forming a liquid-repellent annular film in the predetermined position around the predetermined position where the light emitting element on a board by flexographic printing is arrange | positioned, and on the said board | substrate A predetermined amount of sealing resin is dripped from above the mounted light emitting element, and the process of forming the dome-shaped sealing part which covers the said light emitting element inside the said annular film is provided. Thereby, the manufacturing method of the said light emitting element substrate can manufacture a light emitting element substrate cheaply in a short time compared with the method of forming an annular film using a conventional dispenser etc.

And when the Shore A hardness of the said flexographic printing plate is set in the range of 30 degrees-65 degrees, it becomes hardness suitable for printing with respect to the ceramic substrate etc. which are preferably used as a base material of a light emitting element substrate. Thereby, the manufacturing method of a light emitting element board | substrate becomes it possible to sustain printing (application) of a high precision and a clear pattern for a long time. As a result, the printing durability (printing resistance) of the flexographic printing plate is improved, the life thereof can be extended, and the cost of the process can be reduced.

1 is a perspective view showing a schematic configuration of a light emitting element substrate in an embodiment of the present invention;
2A, 2B, 2C, and 2D are views for explaining a method of manufacturing a light emitting element substrate in an embodiment of the present invention;
3 is a schematic configuration diagram of a flexographic printing press used for application of liquid repellent ink, and
4 is a view showing an example of a shape pattern of the ink holding portion in the flexographic printing plate.

EMBODIMENT OF THE INVENTION Next, embodiment of this invention is described in detail based on drawing.

The light emitting element substrate (LED substrate) in this embodiment is used as a backlight device of an LCD panel, such as a liquid crystal TV, and as shown in FIG. 1, the surface of the flat board | substrate 10 which consists of ceramic, glass, etc. ( A plurality of rows of electrodes 1 are provided in a state aligned with the upper surface), and an LED element 3 (bare chip) is mounted on each electrode 1. Moreover, on each of these LED elements 3, a dome-shaped resin sealing portion 4 covering them is provided, and each light emitting portion 5 of the LED substrate is formed. The characteristic of the said LED board | substrate is that each said sealing part 4 of each said dome shape is formed so that sealing resin may rise up inside the liquid-repellent annular film 2 formed by flexographic printing.

2A to 2D are explanatory views for explaining the manufacturing method of the LED substrate by taking one light emitting unit 5 as an example, and the left column in the figure shows an enlarged cross section of the main part around the light emitting unit 5, and the right column is the above. The state which looked at the light emission part 5 from the upper surface is shown.

The production of the light emitting portion 5 of the LED substrate is first performed as shown in FIG. 2A, for example, on the flat plate-shaped substrate 10 made of ceramic, the electrode 1 for placing (mounting) the LED element 3. (Bump) is formed by etching or the like. And as shown in FIG. 2B, the liquid repellent ink 2 is apply | coated (printed) by flexographic printing around the predetermined position (predetermined position on the said electrode 1) in which the LED element 3 is mounted, and it is dried. To form a liquid-repellent annular coating film 2. Subsequently, as shown in FIG. 2C, the LED element 3 is disposed on the electrode 1 to be electrically connected (mounted), and then, as shown in FIG. 2D, it is loaded inside the annular coating 2. The resin 4 for sealing is dripped and hardened | cured by using Gina dispenser etc., and the dome-shaped sealing part 4 is formed.

The manufacturing method of the said LED board | substrate is demonstrated in detail.

First, the production of the electrode 1 is performed by vapor deposition, etching, or the like on the substrate 10 in a form in which an anode and a cathode are paired at a position where the LED element 3 is to be arranged. Molding (see FIG. 2A). The circuit pattern of the electrode 1 is a method of masking unnecessary parts on the substrate 10 with resin or the like before deposition, or masking necessary parts such as a metal thin film (foil) formed on the substrate 10, It can be formed using a method of removing other unnecessary portions by etching or the like.

Specifically, in the case of forming a gold electrode (gold bump electrode), a thin film of gold is formed on the substrate 10 by vacuum deposition or the like, and then a photosensitive resin (photoresist) is applied thereon, followed by exposure and development to a predetermined value. A resist film of a circuit pattern is formed. The electrode 1 of a predetermined circuit pattern can be obtained by dissolving the gold thin film in a region other than the circuit pattern using a gold etching solution (urea-based liquid or the like) and then removing the resist film.

Subsequently, the liquid repellent ink is applied in a predetermined annular pattern around the position where the LED element 3 is to be placed on the electrode 1 formed on the substrate 10 using a flexographic printing machine. 3 is a schematic configuration diagram of a flexographic printing machine for applying liquid repellent ink to the substrate 10, and FIG. 4 is a diagram schematically showing a pattern of an ink holding part of the flexographic printing plate used for the flexographic printing. In Fig. 3, reference numeral 11 denotes a printing plate, 12 denotes a plate body, 13 denotes an anilox roll, 14 denotes a moving stage, 15 denotes a squeegee, and 16 denotes an ink tank.

Application of the liquid repellent ink using the flexographic printing machine is a process of holding the liquid repellent ink in an ink holding portion formed in a predetermined pattern on the surface of the flexographic printing plate 11, and the flexographic printing plate 11 as shown in FIG. ), And the liquid repellent ink is transferred from the ink holding portion to a predetermined portion around the position where the LED element 3 is to be arranged on the substrate 10.

As the liquid-repellent ink to be used, a liquid-repellent ink containing fluorine, for example, a silicone resin (methylsiloxane, etc.) as a main component, and a liquid-repellent ink (viscosity 0.5 mPa · s to 1000 mPa · s) using a hydrocarbon-based fluorine compound as a solvent It is preferably employed. The solvent may include a fluorine solvent, a silicone solvent, an alcohol solvent, an ether solvent, a glycol ether solvent, and the like.

In addition, the flexographic printing plate 11 to be used is a prepolymer of a urethane acrylate, an acrylate oligomer, an acrylate monomer, and a photopolymerization inhibitor in consideration of the swelling resistance of the solvent (hydrocarbon fluorine compound) of the fluorine-based liquid repellent ink. And a mixture (photosensitive resin composition), such as a photoinitiator, and the Shore A hardness is set in the range of 30 degrees-65 degrees.

In addition, when the Shore A hardness of the flexographic printing plate 11 is less than 30 °, the plate tends to be too soft with respect to the ceramic substrate 10 and wears in a short time, so that high-precision printing cannot be maintained. On the contrary, when the Shore A hardness of the flexographic printing plate exceeds 65 °, there is a tendency to damage the surface of the ceramic substrate 10 and the electrodes, wirings, etc. formed on the surface thereof.

In addition, the flexographic printing plate 11 is preferably the lower the swelling degree of the liquid-repellent ink with respect to the solvent, for example, the swelling rate (volume change rate) for the hydrocarbon-based fluorine compound is preferably 0.5% to 10%. . Therefore, you may use what has a polyester skeleton, a polybutadiene skeleton, a polyether skeleton, a polyvinyl alcohol skeleton, a carbonyl skeleton, etc. in the urethane acrylate which comprises the said flexographic printing plate 11.

On the surface of the flexographic printing plate 11, as shown in FIG. 4, the surface of the flexographic printing plate 11 has fine unevenness around the position corresponding to the predetermined position on which the LED element 3 on the substrate 10 is to be mounted. The convex portion for printing is formed in a predetermined pattern (annular of constant width), and the liquid repellent ink is held in the minute concave portion (ink holding portion) between the fine convex portions. Further, the ink holding amount per unit area held in the ink holding portion is set to about 0.05 ml / m 2 to 50 ml / m 2.

The coating-forming method of the annular coating film 2 using the flexographic printing plate 11 having the above structure is basically carried out in the same procedure as in normal flexographic printing. First, the liquid-repellent ink supplied from the ink tank 16 is supplied to the flexographic printing plate 11 through the anilox roll 13, and the ink holding part of the predetermined annular pattern formed in the surface of the flexographic printing plate 11 is carried out. A predetermined amount of liquid repellent ink is held (ink holding step).

Next, while rotating the flexographic printing plate 11 together with the plate body 12, the substrate (substrate 10 on which the electrode 1 has been formed) disposed on the moving stage 14 is moved in synchronization. The substrate 10 is brought into close contact with the flexographic printing plate 11 so that the liquid-repellent ink retained in the ink holding portion is mounted at a predetermined position on the substrate 10 (LED element 3). Around the scheduled position] (ink transfer step).

Thereafter, the substrate 10 after the liquid repellent ink is transferred is heated by an oven or the like, and the solvent or the like in the ink is evaporated, so that the liquid repellency is around the predetermined position where the LED element 3 is to be mounted as shown in FIG. 2B. The board | substrate 10 in which the annular film 2 which has is formed is obtained. Moreover, the preferable film thickness of the formed cyclic film 2 is 1 nm-1000 nm.

Next, as shown in FIG. 2C, the LED element 3 is adhered (die-bonded) on the electrode 1 through the conductive adhesive (not shown), such as solder paste, on the inside of the annular film 2 to be electrically connected. Connect. In addition, in this embodiment, although the example of bump connection which the LED element 3 is in direct contact with the electrode 1 was shown, the mounting method of these LED element 3 may use other mounting methods, such as wire bonding. .

Thereafter, a sealing resin, a dispenser, or the like is supplied onto the LED element 3 (inside of the annular coating film 2) by a predetermined amount and supplied dropwise. At this time, as described above, since the annular coating 2 having the liquid repellency is formed around the LED element 3 without missing in the circumferential direction, the annular coating 2 is formed by diffusion of the sealing resin ( It functions as a low bed (hill or bank) that suppresses leaking out, and as shown in FIG. 2D, the sealing resin can be raised to a dome shape using its surface tension. In this state, the sealing resin is cured by heating or ultraviolet irradiation or the like to obtain an LED substrate having the domed seal 4.

Thus, in the LED board | substrate of this embodiment, since the liquid-repellent annular film 2 formed by flexographic printing is provided around the LED element 3 arrange | positioned on the board | substrate 10, the dome-shaped sealing part ( The annular film 2 required for formation (rise) of 4) is applied all at once in one pass, as shown in FIG. Therefore, compared with the case where a dispenser etc. are used conventionally, the time required for the process can be shortened significantly.

In the LED substrate, the annular coating 2 is thinner and more uniform than the coating formed using the dispenser or the like, and the film thickness thereof is controlled to be 1 nm to 1000 nm. Therefore, the usage-amount of liquid repellent ink used for formation of the annular film 2 can also be reduced. When the film thickness of the annular coating 2 is less than 1 nm, a uniform and smooth liquid-repellent coating cannot be formed, and the sealing resin tends to flow out of the coating 2. On the contrary, even if the film thickness of the cyclic | annular coating 2 exceeds 1000 nm, the increase of the effect | action which blocks the said sealing resin is not expected, and the cost tends to increase.

In addition, in the manufacturing method of the said LED board | substrate, since the flexographic printing plate 11 used for it is formed with the photosensitive resin composition which consists of a prepolymer of urethane acrylate, an acrylate oligomer, an acrylate monomer, a photoinhibitor, and a photoinitiator, Even when printing using the fluorine-containing liquid repellent ink, the printing plate has high resistance (swelling resistance) to the solvent used in the liquid repellent ink, and the annular coating film 2 having a precise pattern can be clearly printed and applied for a long time. .

In addition, since the Shore A hardness is set in the range of 30 degrees-65 degrees, the said flexographic printing plate 11 has high printing durability (with respect to the ceramic substrate 10 employ | adopted preferably for the said LED board | substrate). And the like, and the damage resistance of the electrode 1, the wiring, and the like formed on the substrate 10 can be avoided. Therefore, the manufacturing method of the LED substrate in this embodiment can improve the lifetime of the flexographic printing plate 11, and can improve the quality and yield of the LED substrate to manufacture.

Moreover, as a urethane type acrylate which comprises the said flexographic printing plate 11, what has a polyester skeleton is preferable.

In addition, in the said embodiment, although the example which used LED as a light emitting element mounted on the board | substrate 10 was demonstrated, you may use other light emitting elements, such as EL and organic EL, as said light emitting element, for example.

Next, an Example is described. However, the present invention is not limited to the following examples.

(Example)

In this embodiment, in the manufacturing method of the light emitting element substrate (LED substrate), the production efficiency when the annular coating film 2 formed around the position where the LED element 3 is to be mounted is applied using the flexographic printing machine, Production efficiency at the time of apply | coating the said cyclic | annular coating 2 using the dispenser etc. was compared conventionally.

The board | substrate used for LED board | substrate and liquid repellent ink are as follows.

〔Board〕

Ceramic plate 70 mm x 70 mm thickness: 0.7 mm

[Liquid repellent ink]

Fluorine-based liquid ink

Solids content: methylsiloxane (3% to 30% by weight)

Solvent (diluent): hydrocarbon-based fluorine compound

Viscosity: 0.5 mPas to 1000 mPas

In addition, the specifications of flexographic printing boards, flexographic printing machines, etc. used for printing (coating) of liquid repellent ink are as follows.

[Flexo printing machine]

FC-33S made in MT technical company

[Flexo printing version]

A flexographic printing plate is a convex printing plate formed by curing a photosensitive resin composition obtained by mixing a urethane acrylate prepolymer, an acrylate oligomer, an acrylate monomer, a photopolymerization inhibitor, and a photopolymerization initiator by ultraviolet irradiation through a negative film.

Flexo printing plate made by Gomo Latech Corporation

    Plate thickness: 2.8 mm Bow: 600 wires / inch Opening ratio: 0% to 40%

    Hardness: 30 ° to 65 ° (Shore A hardness)

    Expansion rate for ink solvents: 0.5% to 10% (weight change rate)

    Ink holding amount of the ink holding portion: 2 ml / m 2 (adjustable width: 0.1 ml / m 2 to 30 ml / m 2)

Coating Pattern (Refer to FIG. 4 for Pattern of Ink Holder)

   Part of the liquid repellent ink coating on the substrate: 200 to 600 places

   Coating pattern (per one place) of liquid repellent ink: round 1.5mmφ (line width 0.1mm)

[Anirox roll]

   Athlete: 400 lines / inch (150 lines / inch to 600 lines / inch)

   Cell capacity (cell volume): 2 ml / m 2 (adjustable width: 0.3 ml / m 2 to 30 ml / m 2)

Printing (coating) of the liquid-repellent ink was performed under the following conditions (refer to FIG. 3 for the schematic configuration of the flexographic printing press).

[Flexo printing condition]

     Print speed (print stage shift amount): 25 m / min (adjustable width: 5 m / min to 30 m / min)

      Anilox Roll Speed: 120 rpm

      Anilox roll printing plate nip width: 6 mm to 7 mm (adjustable width: 1 mm to 15 mm)

      Print plate-to-board nip width: 8 mm to 9 mm (adjustable width: 1 mm to 20 mm)

      Environment of print chamber (at room temperature)

[Drying condition after printing]

      Temperature: 50 ° C. to 100 ° C. Time: 5 seconds to 1 minute

When liquid repellent ink was applied onto the substrate under the above processing conditions, it was possible to process 8,000 sheets per 24 hours as described above, “the LED substrate having 400 required portions of liquid repellent ink per sheet”. This corresponds to a twofold increase in efficiency as compared with the case where the liquid repellent ink is applied using a dispenser (the number of sheets per 24 hours: 4000 sheets) as in the prior art.

In addition, the flexographic printing plate has the Shore A hardness set to 30 ° to 65 °, which is optimal for the ceramic substrate, and thus the substrate can be printed 4000 times in such a state that a printing pattern can be printed without high collapse. Could keep (printing) while printing. In addition, the average film thickness of the applied liquid repellent coating was 0.03 nm, and the amount of the liquid repellent ink used could be reduced by 5% by weight to 30% by weight compared with the case where the liquid repellent ink was applied using the dispenser or the like.

According to the light emitting element substrate of this invention and its manufacturing method, the light emitting element substrate which seals the light emitting element mounted on the board | substrate with resin can be manufactured efficiently and inexpensively.

2: annular film
3: LED device
4: seal

Claims (4)

Board;
A light emitting element disposed on the substrate;
A liquid-repellent annular film formed on the substrate by flexographic printing and disposed around the light emitting element; And
A light emitting element substrate is provided with a dome-shaped sealing portion formed in a state of covering the light emitting element by dropping a sealing resin from above the substrate inside the annular coating. The method of claim 1,
The film thickness of the said annular film is 1 nm-1000 nm, The light emitting element substrate characterized by the above-mentioned. Preparing a flexographic printing plate having an ink holding portion having a predetermined pattern on its surface;
Holding a liquid-repellent ink containing fluorine in the ink holding portion of the flexographic printing plate;
Adhering a substrate to the flexographic printing plate and transferring the liquid-repellent ink from a portion of the ink holding portion of the flexographic printing plate to a predetermined portion around a predetermined position where a light emitting element in the substrate is to be placed;
Evaporating the solvent of the liquid repellent ink after the transfer, and forming a liquid repellent annular film on the surface of the substrate; And
After arranging a light emitting element at the position on the substrate, electrically connecting to an electrode of the substrate, a predetermined amount of sealing resin is dropped from above the light emitting element, and the light emitting element is covered inside the annular coating. The manufacturing method of the light emitting element substrate characterized by including the process of forming a dome shaped sealing part. The method of claim 3, wherein
The Shore A hardness of the flexographic printing plate is set within a range of 30 ° to 65 °.

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