JP6233872B2 - LED manufacturing method - Google Patents

Description

The present invention relates to a method of manufacturing an LED by applying a phosphor to the LED.
In particular, the present invention relates to a method of filling or applying a resin, a solution, a slurry containing phosphor and the like to an LED and then drying and curing, and further relates to a method for manufacturing a white light emitting LED. In the present specification, the LED member means a member or the like as an intermediate part in the process of manufacturing an LED as a finished product, and the application of the present invention means continuous or intermittent dispensing or inkjet. , Micro curtain application, slot nozzle application, screen printing method, atomization application, spraying and the like.

Conventionally, as a method for producing a white light emitting LED, an ultraviolet light or a blue light emitting diode is mixed with a phosphor such as RGB, at least one YAG, TAG, silica (silica) and a binder such as a two-component reaction thermosetting type silicone ( The slurry was dispensed with a dispenser device, or a solvent was added to lower the viscosity, and the LED was directly sprayed on the LED using a spray device, which is a kind of fine particle generator, and coated.

Patent Document 1 discloses a general spraying method in which a slurry containing phosphor, a binder and a solvent is applied to an LED chip heated by the present applicant in a thin film using a compressed air. Then, a method of manufacturing an LED by adhering to the side wall of the LED which is difficult to coat has been proposed.

In Patent Document 2, an LED chip is coated with a binder such as silicone and cured, and a slurry made of a phosphor, a binder and a solvent is applied thereon, and if necessary, a diffusion material or the like is applied. A method of laminating them by mixing them has been proposed.

A method using a dispenser as disclosed in Non-Patent Document 1 is mounted inside a cup such as a bullet-type LED that is not high power or a backlight (back light). Many of these chips are used for mass production by filling the slurry.

However, in the method of Patent Document 1, the slurry can be applied in a pulsed manner, so that the side wall of the LED chip can also be coated, and since the thin film is applied in multiple layers, the edge cover of the LED chip is good and the coating efficiency can be extremely high. The application efficiency of the phosphor was low because it was applied between the LED incorporated in the LED substrate such as the LED, or unnecessary portions were applied as a mask. In particular, the efficiency was extremely poor when the distance between the LEDs was large.

Patent Document 2 discloses a method in which a binder is coated on an LED chip and cured, and then a slurry containing phosphor is coated thereon by an air spray method. However, the coating efficiency is poor with ordinary air spray. In addition, it can be easily predicted that the use efficiency of the phosphor is lower than that of Patent Document 1.

On the other hand, when a slurry made of a binder such as solventless silicone and a phosphor is applied with a dispenser using a simple device as disclosed in Non-Patent Document 1 or the like, masking is not required and productivity is high. As shown in FIG. 7, the center of the LED chip swells, the end becomes thin, and not only vertical light but also the spatial distribution is bad, which is unsuitable for high power illumination.
Further, even if it is cup-shaped, the film thickness is thick, so that light loss occurs due to irregular reflection or the like, leading to phosphor loss.

WO2011 / 083841A1 US8058088B2

Musashi engineering catalog

The screen printing method uses a two-component curing type of binder silicone resin, so it cannot be used for a long time due to pot life, but it has been necessary to create a large amount of slurry to stabilize the coating quality. Was extremely low. The electrophoretic method of US6576488B2 that can form a phosphor film uniformly was ideal, but the process was complicated and it was apt to be avoided in the industry.
There has been a need in the industry to form a phosphor film as thinly and uniformly as possible on an LED chip to increase the usage efficiency of the phosphor.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an LED manufacturing method that has far superior performance than conventional methods and high use efficiency of phosphors.

The present invention includes a first step of filling or coating at least one layer of a mixture of a binder alone or a first phosphor and a binder, the weight ratio of which is 0.00: 1 to 1: 1. A second step of setting a mask in which at least a portion of the LED is opened on the coated layer or the LED member, and a slurry ratio of the second phosphor and the solvent alone or the weight ratio of the second phosphor and the binder. An LED comprising a third step of filling or coating at least one layer of slurry comprising a mixture of 1: 0.00 to 1: 0.5 and a solvent, and collecting the phosphor adhering to the mask A manufacturing method is provided.

In the manufacturing method of the present invention, the second phosphor is selected from at least one phosphor selected from red, green, blue and yellow, and the mask is prepared corresponding to each color. An LED manufacturing method is provided.

In the manufacturing method of the present invention, it is preferable that the first phosphor and the second phosphor are of the same type.

In the manufacturing method of the present invention, the LED is preferably a wafer level LED or an LED mounting substrate.

In the manufacturing method of the present invention, a first step of setting a mask having at least an LED portion opened on the wafer level LED or LED mounting substrate, and a binder alone or a first fluorescent light on the LED heated to 30 to 120 ° C. A second step of filling at least the periphery of the LED with a mixture comprising a body and a binder in a weight ratio of 0.00: 1 to 1: 1, and a slurry or second phosphor comprising a second phosphor and a solvent. And a third step of filling or coating at least one layer of slurry comprising a mixture having a weight ratio of 1: 0.00 to 1: 0.5 and a solvent. Provided is a method for manufacturing an LED, comprising collecting a phosphor or a mixture of a second phosphor and a binder.

In the manufacturing method of the present invention, the slurryy coating containing at least the second phosphor is applied by spraying a spray flow using a compressed gas, or transporting and applying the fine particles generated by the fine particle generating device on a jet flow. An LED manufacturing method is provided.

In the production method of the present invention, it is preferable that the transport of the spray flow or fine particles on the jet flow is performed in a pulsed manner of 5 to 200 Hz.

In the manufacturing method of the present invention, an LED manufacturing method is characterized in that the mask is removed and a binder is applied with a dry cured film thickness of 5 micrometers or less from a slurry layer containing at least a second phosphor. provide.

According to the production method of the present invention, since the first binder or the mixture layer of the first phosphor and the binder is rich in binder, there is no problem in adhesion with the lens mold in the final process. A solvent is added to the first layer binder or the first phosphor and binder mixture to increase fluidity, and filling or coating such as pulsed spraying can be easily performed. The slurry layer phosphor containing the second phosphor can be deposited so as to sink into the binder or binder rich layer by impacting the pulsed spray or transporting it in a jet stream.

As described above, according to the present invention, the side wall and the edge of the LED can be covered, or the same effect as that can be obtained, and the expensive phosphor can be easily recovered. Can be manufactured at low cost.

It is a schematic sectional view by a conventional special spray coating method. 1 is a schematic cross-sectional view according to an embodiment of the present invention. 1 is a schematic cross-sectional view according to an embodiment of the present invention. 1 is a schematic cross-sectional view according to an embodiment of the present invention. 1 is a mask according to an embodiment of the present invention. It is a schematic sectional drawing of LED obtained by this invention. It is a schematic sectional drawing by the conventional dispensing system. 1 is a schematic cross-sectional view according to an embodiment of the present invention. 1 is a schematic cross-sectional view according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The following embodiments are merely examples for facilitating understanding of the invention, and exclude additions, substitutions, modifications, etc. that can be implemented by those skilled in the art without departing from the technical idea of the present invention. is not.

The drawings schematically show a preferred embodiment of the invention.

In FIG. 1, LEDs are stacked with a thin film while giving an impact to a slurry pulsed splay flow, more specifically, using the method and apparatus of Japanese Patent Application No. 2011-200395 to which the present applicant has the right. Thus, the side surface can also be coated and the coating efficiency can be 90% or more, and a suitable coating film can be formed. However, since unnecessary portions are applied, the use efficiency of the phosphor was extremely poor. When the pitch between the LEDs on the substrate is wide, the usage efficiency of the phosphor is often less than 10%.

In order to improve performance, a thin film is required, and the ratio of the phosphor is required to be larger than that of the binder. If too much phosphor is used, the adhesion to the substrate is deteriorated during resin lens molding. Needed a mask.
In the first modification of the embodiment of the present invention shown in FIG. 2 and subsequent figures, the portions corresponding to the LEDs shown in FIG. 1 are sequentially added with 10, 20, 30, 40, 50, 60 to the reference numbers in FIG. The difference from FIG. 1 will be mainly described below.

In FIG. 2, the mask 14 is set so as not to interfere with the LED chip 11 and the wire 12. Then, a binder or a binder-rich slurry is filled or applied from the mask opening, and if necessary, curing of the binder is promoted, and then a slurry made of the second phosphor is filled or coated thereon. The binder or the mixture of the first phosphor and the binder is preferably diluted with a solvent so that it can be easily filled or applied and bubbles are not easily mixed. In order to more uniformly disperse the phosphors, it is important to fill or apply the slurry including the first phosphor and the slurry including the second phosphor in a plurality of times. When filling the slurry containing the binder or the first phosphor, the filling level of the dried and cured slurry is set to ± 30 micrometers of the LED height to improve the edge cover and reduce the total film thickness. It is preferable because the spatial color temperature can be easily adjusted. Further, in order to prevent the phosphor from being settled after filling, it is preferable to accelerate the curing of the binder every time any mixture or slurry is filled or coated.

In FIG. 3, an LED or a substrate including the LED is coated with a binder or a mixture including a first phosphor. A solvent or a diffusing material may be added to the mixture. Although a coating apparatus is not ask | required, the pulsed spray which added the impact is suitable.
In the case of coating the entire substrate, the phosphor content is preferably 50% or less by weight in consideration of the adhesion of the lens mold resin in the subsequent process, and ideally 3 to 30%. The reason is that if a phosphor is present rather than only a binder, thixotropic properties are improved and side wall dripping and edge shrinkage are unlikely to occur. The content should be determined by the amount of light emitted from the side of the LED and color conversion per volume. Moreover, when setting a mask, it is preferable to accelerate | stimulate hardening of a binder to the extent of touch dryness.
In addition, when applying the slurry containing the second phosphor and the binder, it is convenient from the viewpoint of recovery that the mask is slightly lifted from the substrate because the speed of curing of the binder on the mask can be suppressed. Usually, an LED is adsorbed by an adsorption heating table to improve heat conduction, and can be achieved by weakening the adsorption force. After filling or coating, the curing of the binder can be accelerated rapidly by quickly removing the mask and adsorbing it to increase the heat conduction from the table heated to 30 to 120 ° C.

In FIG. 4, the second slurry is spray-coated with an applicator on at least a part of the slurry coating layer including the binder or the first phosphor filled around the LED 31 or, if necessary, to the LED upper portion with a coating device. The body layer 35 is formed. When the applicator is traversed and the phosphor particle size distribution is taken into account, it is possible to disperse the phosphor more uniformly by spraying 3 to 15 layers of thin film, so that the performance is improved. In order to make the color temperature distribution of the LED ideal, a mask 34 is set on the top of the LED, and the mask opening and coating area should be determined by the structure of the LED, the ratio of the phosphor around or above the LED, etc. .
Further, except for the Philip chip type, the mask position is set higher than the wire 32, so that handling becomes easy and automation can be achieved.

In FIG. 5, an opening is formed in the mask 44 so that the LED chip and wires do not interfere with each other.

FIG. 6 is a coating film formed according to the present invention. The slurry layer 53 containing the binder or the first phosphor may be a plurality of layers, and the slurry layer 55 containing the second phosphor is preferably a plurality of layers. The cover coat layer 55 can be formed of a thin film with only the binder so that the phosphor is not detached by vibration or the like after the slurry having only the second phosphor having substantially no binder is applied. Of course, the entire substrate can be coated to, for example, 5 micrometers or less.

FIG. 7 is a schematic diagram in which a slurry including phosphor is applied to the LED 61 in a conventional dispenser or the like. The film thickness at the center is thick and the edge cannot be covered, so that the color temperature varies. If the coating amount is small, the vicinity of the pad to which the lead wire 62 is bonded is shaded and is not easily applied.

FIG. 8 and FIG. 9 show an image in which the second phosphor or the particles 79 made of the second phosphor and the binder collide with the binder or the binder rich layer 78 by the spray flow or the jet flow and enter.

In the prior art, for example, a phosphor having a high specific gravity having an average particle size distribution of about 8 micrometers and a distribution of 1 micrometer or less to 30 micrometers, a binder having a relatively low specific gravity, and a solvent added if necessary. It was extremely difficult to apply the slurry with a thin film at a time with a variation of ± 1.5% per unit area. From a microscopic viewpoint, there are naturally large portions and small portions of particles.

In the present invention, the technique of Japanese Patent Application No. 2011-200395 is applied to the dispersion, filling, and coating of slurry containing the first binder or slurry and second phosphor, and a syringe, applicator, and small pump (not shown), for example, filled with slurry. In the applicator by forming a stirring and pumping mechanism in the circulation circuit including the syringe filled with the slurry. Return to the upstream of the syringe through the pressurized flow and circulate, or alternately move the slurry between the two syringes with a differential pressure, and moving to one syringe increases the flow rate with a hydraulic pressure difference of 15 KPa to 40 Kpa and generates a jet Then, the slurry which is uniformly dispersed is discharged and applied as thin as possible with a thin film.
In particular, in order to disperse slurries with virtually zero or extremely few binders, it is important to disperse by increasing the flow rate.

By doing so, the particle size distribution of the coating film can be made uniform from the viewpoint of probability. Furthermore, a good dispersion state can be maintained by adding vibrations such as ultrasonic waves to a preferable portion of the circulation circuit. Furthermore, in the formation of a suitable coating film, the surface of the LED is made conductive as in electrophoresis. For example, in the case of spray coating, the atomized particles are electrostatically repelled by charging the atomized particles with static electricity. Therefore, it is possible to apply an ideal phosphor.

In addition, the present invention is not limited to applying a single type of slurry to multiple layers with a single applicator, and multiple phosphors can be applied in multiple layers with multiple applicators. That is, according to the present invention, an LED can be manufactured by using a coating apparatus in which a plurality of applicators are installed in one coating booth and laminating and drying a plurality of different types of phosphors on the LED. The laminate of the at least two types of phosphors can be selected from at least red, green, yellow, and blue phosphors.

In addition, the slurryy phosphor containing at least the second phosphor is preferably a slurry with at least a binder of 0 and a binder reduced as much as possible, which is suitable in terms of recovery and reuse of the phosphor. It is.

The size, shape, and material of the mask are not limited as long as they are suitable for the recovery of the phosphor, but when the phosphor is recovered and reused with high performance, a ceramic material that is difficult to be polished with the phosphor is ideal.

Also from the viewpoint of contamination, a material such as ceramic that is the same as or does not affect the material used for the LED surface or phosphor is preferable.
In particular, in order to reuse the mask and increase the recovery efficiency, coating the mask with a fluorine or ceramic treatment agent such as anti-contamination applied to building exterior wall boards, etc., causes the coating on the mask that has been gelled. The film is easy to peel off. For high-speed production, for example, a heat- and solvent-resistant plastic film, such as fluorine-based or polyimide amide resin, is partially or partially coated on the substrate with silicone-based or cross-linked acrylic urethane. It is also possible to laminate in advance by applying a heat- and solvent-resistant adhesive such as a system.

When the applicator transports phosphor particles by jet flow after the sprayer is made into air spray, air-assisted spray, or particularly slurry made of the second phosphor by the particle production apparatus, the pattern width on the surface of the LED substrate is 1 to It is preferable to be about 20 mm. The pattern width should be selected in consideration of the film thickness of each desired portion of the entire chip depending on the shape and type of the chip. In order to obtain the desired film thickness on the edge and side wall of the LED chip, both the phosphor particles and the jet stream are pulsed even when transported by a pulsed spray method with impact according to Japanese Patent Application No. 2011-200395 or jet stream. More effective.

Heating the LED to a range of 30 to 120 ° C. in consideration of promoting flow properties and curing of the binder when spraying, temperature decrease due to heat of vaporization generated during coating formation such as spraying, etc. The distance from the head is set to 5 to 90 mm, the spray pattern width when reaching the LED is set to 1 to 20 mm, the spray air pressure is ejected in pulses at 0.1 to 0.4 MPa, and the impact is effected in pulses. It is preferable to spray while giving.
Further, when using a slurry made of a binder such as silicone that is difficult to wet, it is difficult to cover the side walls and the edges in particular unless they impact the coating material and collide with the surface of the object to be coated for LED.

Regardless of single color or multiple colors, especially slurries containing the second phosphor measure the color temperature and weight for each layer or in the layer before the required layer or the last layer, and correct the coating amount if necessary The desired quality can be achieved.

According to the present invention, since expensive phosphors are collected and reused while keeping high value-added LEDs in high quality, the usage efficiency can be increased by 10 times or more compared with the conventional process, so the cost can be greatly reduced. it can.

1, 11, 21, 31, 41, 51, 61, 71 LED chips 2, 12, 22, 32, 42, 52, 62 Wires 3, 63 Phosphor layers 13, 23, 33, 43, 53 Binder, first Phosphor layers 14, 34, 44 Masks 15, 25, 35, 55 Second phosphor layer 56 Binder (cover layer)
78 First phosphor 79 Second phosphor

Claims (4)

A step of preparing a binder-rich first slurryy in which the ratio of the slurry phosphor comprising at least the phosphor and the binder is 50% or less by weight corresponding to the amount of light emitted from the side surface of the LED chip; A step of setting a mask around the periphery, and the volume between the LED chip filling the first slurry and the mask corresponds to the amount of light emitted from the side of the LED chip and the color conversion of the first slurry. Filling the first slurry so as to be plus or minus 30 micrometers from the opening of the mask to the height of the LED chip, accelerating the curing of the binder, and at least above the LED chip A method for manufacturing an LED, comprising a step of filling or applying a second phosphor-rich slurry. 2. The LED manufacturing method according to claim 1, wherein a plastic film to which an adhesive is applied is laminated on the LED substrate in advance. The LED is heated to 30 to 120 ° C., the first slurry and the second slurry both contain a solvent, and the first slurry is filled or coated in multiple layers, and is filled or coated each time. 3. The method of manufacturing an LED according to claim 1, wherein the second slurry is laminated with a thin film. The second slurry is a slurry composed of a phosphor of a plurality of colors selected from red, green, yellow, and blue phosphors and a binder, and each of the second slurries is applied by a plurality of applicators corresponding to the slurries of each color. 4. The method for manufacturing an LED according to claim 1, wherein a plurality of thin films are applied.

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