KR20160017697A - Method for Manufacturing LED Device Using Phosphor Film Attaching Method - Google Patents

Abstract

The present invention relates to a method to manufacture an LED device, capable of manufacturing an LED device by forming a fluorescent layer on an LED chip. According to the present invention, the method includes: a step (a) of preparing multiple LED chips, individually cut on a wafer; a step (b) of preparing multiple fluorescent covers, made of synthetic resin materials mixed with fluorescent materials in order to cover the upper surfaces of the LED chips, according to the thickness of the fluorescent cover and a mixture amount of the fluorescent materials; a step (c) of measuring a color coordinates value of each of the LED chips; a step (d) of selecting a fluorescent cover, able to form a target color coordinates value by being applied to the LED chip of which color coordinates value is measured at the step (c), among multiple fluorescent covers; and a step (e) of forming an LED device by attaching the selected fluorescent cover to the LED chip.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a LED cover,

The present invention relates to a method of manufacturing an LED element, and more particularly, to a method of manufacturing an LED element by attaching a fluorescent cover to an LED chip.

Generally, a light emitting diode (LED) is manufactured by cutting an LED chip manufactured on a wafer and forming a fluorescent layer thereon. The LED chip usually emits blue or red light. When a fluorescent material containing a fluorescent material is applied to the LED chip, the color produced by the LED device varies depending on the amount of the fluorescent material. By emitting an appropriate amount of the fluorescent liquid to the LED chip, it is possible to manufacture white light or various other LED elements of various colors.

Korean Patent Laid-Open Publication No. 2013-0081029 discloses a method of dispensing a phosphor-containing liquid resin with a predetermined discharge amount in an LED package and adjusting a discharge amount of the phosphor-containing liquid resin so that the target color coordinate is obtained based on a target color coordinate (CIE rank) A method of manufacturing a light emitting device that provides a method of manufacturing an LED package and a phosphor-containing liquid resin dispensing apparatus are disclosed.

Recently, it has become increasingly difficult to apply a small amount of a fluorescent material to a LED chip in a fixed amount while the size of the LED chip is becoming smaller. It is also difficult to keep the thickness of the phosphor formed on the upper surface of the LED chip constant.

In order to solve such a problem, a method of separately manufacturing a phosphor in the form of a film, attaching it on a wafer, and cutting the LED together with the LED chip has been attempted.

On the other hand, LED chips are made in the form of wafers in the manufacture of LED devices. In general, one or more tens of thousands of LED chips are formed on one wafer. Most of the LED chips belonging to the same wafer are mixed with good and defective products due to the characteristics of the LED chip manufacturing process, and the characteristics such as the color coordinate values of the LED chips are different.

Therefore, when a phosphor film having the same thickness or the same fluorescent substance density is attached to a plurality of LED chips having different color coordinate values on a wafer, the characteristics such as the color coordinate value of the LED element to be manufactured appear differently, There arises a problem that it is difficult to fabricate an LED element having a light emitting layer.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned needs, and it is an object of the present invention to provide a fluorescent cover having various optical characteristics, And an object of the present invention is to provide a method of manufacturing an LED device with a fluorescent cover attachment method capable of manufacturing a device.

According to another aspect of the present invention, there is provided a method of manufacturing an LED device, including the steps of: (a) forming a plurality of LED chips ; (b) providing a plurality of fluorescent covers formed of a synthetic resin material mixed with a fluorescent material and covering the upper surface of the LED chip according to a mixing amount of the fluorescent material or a thickness of the fluorescent cover; (c) measuring color coordinate values of the LED chip provided in the step (a); (d) selecting a fluorescent cover capable of implementing a target color coordinate value by applying to the LED chip in which the color coordinate value is measured in the step (c), among the plurality of fluorescent covers; And (e) attaching the fluorescent cover selected in the step (d) to the LED chip to form an LED element.

According to the method of manufacturing an LED device according to the present invention, a fluorescent cover having appropriate optical characteristics is selected according to the color coordinate values of each prepared LED chip, and the fluorescent cover is attached to the LED chip, thereby effectively manufacturing an LED device having desired optical characteristics.

Further, in the method of manufacturing an LED device according to the present invention, after a fluorescent cover is attached to an LED chip to form an LED device, if the color coordinate value of the LED device differs from the target color coordinate value, the fluorescent material is coated on the fluorescent cover of the LED device It is possible to easily correct the color coordinate value of the LED element, thereby manufacturing a high-quality LED element.

FIG. 1 is a process diagram showing steps of a method of manufacturing an LED device with a fluorescent cover according to an embodiment of the present invention.
FIG. 2 shows a step of forming an LED element in a method of manufacturing an LED element with a fluorescent cover according to an embodiment of the present invention.
FIG. 3 illustrates a step of attaching an LED chip and a fluorescent cover in a method of manufacturing an LED device with a fluorescent cover according to an embodiment of the present invention.
4 is a view illustrating a step of correcting a color coordinate value in a method of manufacturing an LED device with a fluorescent cover according to an embodiment of the present invention.
FIG. 5 is a side view showing an example of an LED device manufactured through a method of manufacturing an LED device with a fluorescent cover according to an embodiment of the present invention.
6 is a side view showing another example of an LED device manufactured through a method of manufacturing an LED device with a fluorescent cover according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, a method of manufacturing an LED device with a fluorescent cover according to the present invention will be described in detail.

FIG. 1 is a process diagram illustrating a method of manufacturing an LED device with a fluorescent cover according to an exemplary embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a method of manufacturing an LED device with a fluorescent cover according to an embodiment of the present invention. FIG. 3 illustrates a step of attaching an LED chip and a fluorescent cover in a method of manufacturing an LED device with a fluorescent cover according to an embodiment of the present invention, and FIG. 4 is a cross- And a color coordinate value correction step in a method of manufacturing an LED element with a fluorescent cover.

As shown in FIGS. 1 to 4, a method of fabricating an LED device using a fluorescent cover according to an embodiment of the present invention includes steps of forming LED elements (S10 to S50), correcting a color coordinate value of the LED element S70). According to the method of manufacturing the LED device according to the present embodiment, a fluorescent cover 12 containing a fluorescent material is separately prepared and attached to the LED chip 10, whereby an LED device having a fluorescent layer formed on the LED chip can be manufactured have.

1 to 3, the LED element forming step includes the steps of providing the LED chip 10 (S10, (a), FIG. 2 (a)), and arranging a plurality of fluorescent covers 12 (Step S30) of measuring the color coordinate value of the LED chip 10 (step S30, step (c)), selecting the appropriate fluorescent cover 12 (step S40, step (d) And attaching the fluorescent cover 12 to the LED chip 10 (S50, step (e), FIGS. 2 (b) and 2 (c)).

The LED chip 10 is formed on the wafer as usual. In step S10 of providing the LED chip 10, the LED chip on the wafer may be cut into chips and transferred to a carrier such as a blue sheet. In general, on one wafer, tens of thousands of LED chips are formed. Most of the LED chips belonging to the same wafer are mixed with good and defective products due to the characteristics of the LED chip manufacturing process, and the optical characteristics such as the CIE rank value of each LED chip are different. Therefore, in the process of separating the LED chip from the wafer, defective products can be filtered out through a characteristic inspection.

The fluorescent cover 12 is made of a synthetic resin material mixed with a fluorescent material so as to cover the upper surface of the LED chip 10. In step S20 of providing the fluorescent cover 12, a plurality of fluorescent covers 12 having various optical characteristics are prepared according to the amount of the fluorescent material and the thickness thereof. The fluorescent covers 12 to be prepared can be sorted according to the optical characteristics such as the color coordinate values and stored at predetermined positions.

In step S30 of measuring the color coordinate value of the LED chip 10, the color coordinate values of each of the prepared plurality of LED chips 10 are measured. The color coordinate value of the LED chip 10 can be measured with a measuring device while driving the LED chip 10 by applying power to the LED chip 10. In this process, other optical characteristics of the LED chip 10 such as a light amount and an optical wavelength can be measured in addition to the color coordinate value of the LED chip 10. The color coordinate value measurement of the LED chip 10 may be performed on the carrier after being separated from the wafer or may be performed on the wafer. If the color coordinate values of the LED chip 10 are measured and the LED chips 10 are classified according to their optical characteristics, subsequent work can be smoothly performed. In this case, information on the color coordinate value of each LED chip C can be stored in a control unit such as an attaching device (not shown) together with the positional information of each LED chip C.

In order to attach the fluorescent cover 12 to the LED chip 10, one fluorescent cover 12 is selected from among the plurality of fluorescent covers 12 in consideration of the color coordinate value of the target LED chip 10 (S40) . That is, the color coordinate value is attached to the measured LED chip 10 to select the fluorescent cover 12 capable of realizing the target color coordinate value. Here, the target color coordinate value is a value preset to the final color coordinate value required for the LED element to be produced. At this stage, the combination of the color coordinate values of the various LED chips 10 and the color coordinate values of the various fluorescent covers 12 and the final color coordinate values obtained by various combinations of these are preliminarily data, and the operator or the automation machine uses the data The fluorescent cover 12 suitable for the target LED chip 10 can be selected.

When a suitable fluorescent cover 12 for the target LED chip 10 is selected, these are attached as shown in Figs. 2 (b) and 2 (c) (S50). The step of attaching the LED chip 10 and the fluorescent cover 12 includes the steps of applying the adhesive 14 on the LED chip 10 (step (e-1)), picking up the selected fluorescent cover 12, 14) by a method of pressing on the coated LED chip 10 (step (e-2)).

A pick-up tool 50 as shown in Fig. 3 is used for picking up the selected fluorescent cover 12 and carrying and pressing the selected fluorescent cover 12 to the LED chip 10 to which the adhesive 14 is applied. Pickup tool 50 includes a pick-up head 52, a VCM lift actuator 54, and a rotary actuator 56. The pick- The pickup head 52 can pick up the fluorescent cover 12 by a method such as suction. The pick-up head 52 is coupled to the rotary actuator 56 and can be rotated by the rotary actuator 56. The rotary actuator 56 is coupled to the VCM elevating actuator 54 and elevated by the VCM elevating actuator 54.

Therefore, the pickup head 52 is moved up and down by the action of the VCM lift actuator 54 to pick up the fluorescent cover 12 or to press the picked up fluorescent cover 12 against the LED chip 10 coated with the adhesive 14 It can be attached by the method. The pickup head 52 is rotated by the rotary actuator 56 so that the picked up fluorescent cover 12 can be aligned with the posture of the LED chip 10. For this purpose, the LED chip 10 and the fluorescent cover 12 can be photographed before the fluorescent cover 12 is pressed and attached to the LED chip 10, and the angular displacement therebetween can be detected.

The VCM lift actuator 54 uses a voice coil motor (VCM), and can accurately raise and lower the pick-up head 52 picking up the fluorescent cover 12. As is known, the VCM uses the Lorentz force generated by the induction magnetic force of the coil in a static magnetic field by a permanent magnet as kinetic energy, and a precision linear motion system requiring a relatively short travel distance It is a linear transport actuator suitable for driving. The VCM lift actuator 54 has a VCM structure, so that it is small in size, light in weight, and simple in structure. It can also work with a variety of driving algorithms. As described above, by using the VCM elevating actuator 54, the fluorescent cover 12 can be pressed and attached to the LED chip 10 with an appropriate pressure.

As the adhesive 14 for attaching the LED chip 10 and the fluorescent cover 12, a transparent adhesive liquid or a fluorescent liquid may be used. The fluorescent liquid is a mixture of a liquid synthetic resin and a fluorescent substance powder. When a fluorescent material is used as an adhesive, the fluorescent material can be applied to the LED chip 10 or the fluorescent cover 12 using the method and equipment used in the color coordinate value correction step to be described later.

The LED element 18 can be formed by attaching the LED chip 10 and the fluorescent cover 12 using the adhesive 14 and curing the adhesive 14 as shown in Fig. Various methods can be used for curing the adhesive 14. The adhesive 14 may be cured by passing the time at room temperature, and heat may be applied to improve the curing rate. When the fluorescent material is used as the adhesive 14, the fluorescent material interposed between the LED chip 10 and the fluorescent cover 12 is cured to form a fluorescent film, thereby improving the optical characteristics of the LED device.

After the LED element 18 is formed, a color coordinate value correction step (S60 to S70) of the LED element is performed as shown in Figs. 1 and 4. The step of correcting the color coordinate value of the LED element comprises the steps of measuring the color coordinate value of the LED element 18 (steps S60 and F) and applying the fluorescent agent L to the LED element S70 ) Step).

In the color coordinate value measurement step S60 of the LED element 18, power can be applied to the LED element 18 to drive the LED element 18, and the measurement can be performed by the measuring device. In this process, in addition to the color coordinate value of the LED element 18, other light characteristics of the LED element 18 such as the light amount and the light wavelength can be measured

In the fluorescent substance applying step S70, a fluorescent liquid is applied on the fluorescent cover 12 of the LED element 18 to correct the color coordinate value of the LED element 18. [ That is, if the measured color coordinate value of the LED element 18 is different from the target color coordinate value, the phosphor coating can be applied on the fluorescent cover 12 by applying the fluorescent liquid so that the color coordinate value of the LED element 18 can be adjusted to the target color coordinate value. Fluorescent liquid application uses an EHD (Electro-Hydrodynamic) pump 100 as shown in FIG. The EHD pump 100 applies a suitable amount of the fluorescent liquid onto the fluorescent cover 12 according to the measured color coordinate value of the LED element 18 to form a fluorescent film having a proper thickness so that the color coordinate value of the LED element 18 becomes the target color coordinate value As shown in FIG. The EHD pump 100 applies the fluorescent liquid to the target LED element 18 on the basis of the data. Of course, the application amount of the fluorescent substance by the EHD pump 100 can be appropriately adjusted by the operator.

The EHD pump 100 includes a pump body 130, a voice coil motor (VCM) 110, a work plate 200, a power supply unit 170, and a control unit 180.

The pump body 130 includes a reservoir 131, an inlet pipe 132, a nozzle 150, and a valve rod 120. The storage unit 131 is formed in the pump body 130 so as to extend vertically and the inlet pipe 132 is formed in the pump body 130 to be connected to the storage unit 131. Fluorescent liquid L supplied from the outside through the inflow pipe 132 is stored in the storage unit 131. A nozzle 150 is disposed below the storage unit 131 and the fluorescent liquid L stored in the storage unit 131 is discharged downward through the nozzle 150. The valve rod 120 is inserted into the storage part 131 from the upper side and is installed to be movable up and down with respect to the storage part 131. The space between the upper side of the storage part 131 and the valve rod 120 is sealed so that the fluorescent liquid L does not flow out to the outside of the storage part 131.

The voice coil motor 110 is disposed above the pump body 130. The voice coil motor 110 includes a permanent magnet 111, a coil 112, an elevating member 114, and a fixing member 113. The fixing member 113 is fixed to an external device to which the pump body 130 is fixed. The stationary member 113 is provided with a permanent magnet 111. The elevating member 114 is provided so as to be movable up and down with respect to the fixing member 113. The lifting member 114 is provided with a coil 112. An electromagnetic force generated in the coil 112 by the power supplied to the coil 112 acts on the permanent magnet 111 to move the elevating member 114 up and down with respect to the fixing member 113. [

The control unit 180 supplies power to the voice coil motor 110 to control the operation of the voice coil motor 110 and to control the displacement of the elevation member 114. [ The control unit 180 may operate the up / down member 114 to oscillate up / down at a specific frequency by adjusting the power applied to the voice coil motor 110, or may raise / .

The work plate 200 is disposed below the pump body 130 and the LED element 18 to be coated with the fluorescent liquid L is disposed on the work plate 200.

One side of the power supply 170 is connected to the nozzle 150 of the pump body 130 and the other side is connected to the work plate 200 or the LED element 18. In this embodiment, a case where the power supply device 170 is connected to the work plate 200 will be described as an example. The control unit 180 is connected to the power supply unit 170 to control the power of the power supply unit 170. When a potential difference is generated between the fluorescent liquid L inside the nozzle 150 and the work plate 200 by the power supply unit 170 and the fluorescent liquid L in the nozzle 150 is discharged by the electrostatic force from the nozzle 150, And is discharged to the LED element 18 on the work plate 200.

The inlet valve 140 is installed in the inlet pipe 132 of the pump body 130 to open and close the inlet pipe 132. The operation of the inflow valve 140 for opening and closing the inflow pipe 132 is controlled by the control unit 180.

The procedure of applying the specific fluorescent fluid by the EHD pump 100 is as follows.

When the voice coil motor 110 raises the valve rod 120 with the control unit 180 opening the inlet valve 140, the fluorescent liquid L is supplied to the inside of the storage unit 131 through the inlet pipe 132 Lt; / RTI >

When the storage unit 131 is filled with the fluorescent liquid L, the control unit 180 operates the inlet valve 140 to close the inlet pipe 132. In this state, when the control unit 180 operates the voice coil motor 110 to lower the valve rod 120, the fluorescent liquid L is discharged through the nozzle 150 by the pressure inside the storage unit 131 . By such an operation, it is possible to discharge the fluorescent liquid L of a relatively large capacity. In this case, the EHD pump 100 of the present embodiment operates in a manner similar to that of the linear pump.

If necessary, the EHD pump 100 of the present embodiment can be operated as follows. First, the inflow valve 140 is opened and the fluorescent liquid L is introduced into the storage unit 131. At this time, the inflow pipe 132 is connected to an external syringe which continuously supplies the fluorescent liquid L at a constant pressure. In this state, the control unit 180 operates the voice coil motor 110 to vibrate the valve rod 120 up and down at a high speed.

The controller 180 can easily control the displacement and the operating frequency of the voice coil motor 110 so that the EHD pump 100 of the present embodiment applies the fluorescence liquid L very rapidly and at the same time, ) Can be applied. Particularly, even when the voice coil motor 110 has a relatively small volume, it is easy to construct a structure that generates a very strong force in accordance with the applied voltage, the winding of the coil 112, the strength of the permanent magnet 111, Applying the same configuration to a fluorescent fluid (L) pump has many advantages.

When the control unit 180 operates the power supply unit 170 to generate a potential difference between the nozzle 150 and the work plate 200, the electrostatic force acting on the fluorescent liquid L in the nozzle 150 The fluorescent liquid L is dropped to the LED element 18 on the work plate 200. Since the control unit 180 can discharge the fluorescent liquid L in units of droplets in accordance with the method of controlling the power supply unit 170 in discharging the fluorescent liquid L in this manner, There is an advantage that the discharge amount of the liquid L can be controlled very finely.

As described above, when the fluorescent liquid is applied onto the fluorescent cover 12 by the EHD pump 100, the fluorescent liquid L dropped on the fluorescent cover 12 is uniformly coated on the fluorescent cover 12 while flowing on the fluorescent cover 12. [ do. By curing the fluorescent liquid, the LED element 20 provided with the fluorescent film 22 on the fluorescent cover 12 can be formed as shown in Fig. Various methods can be used for curing the fluorescent liquid (L). By lapse of time at room temperature, the fluorescent substance L may be cured or heat may be applied to improve the curing rate.

As described above, according to the method of manufacturing an LED device according to the present embodiment, a fluorescent cover 12 having appropriate optical characteristics is selected according to the color coordinate values of each LED chip 10 prepared and attached to the LED chip 10, It is possible to effectively manufacture the LED element 18 having the above-described structure.

If the color coordinate value of the LED element 18 is different from the target color coordinate value after attaching the fluorescent cover 12 to the LED chip 10 to form the LED element 18, It is possible to easily correct the color coordinate value of the LED element 18 by applying the fluorescent liquid L onto the LED element 12, thereby manufacturing a high-quality LED element 18.

6 is a side view showing another example of the LED device manufactured through the method of manufacturing an LED device according to the present invention.

The LED element 25 shown in Fig. 6 is provided with a fluorescent substance concentration portion 27 at the center thereof. The fluorescent substance concentration portion 27 can be formed by using the EHD pump 100 shown in Fig. That is, the fluorescent substance L can be concentratedly applied to the center of the fluorescent cover 12 by the EHD pump 100 to form the fluorescent substance concentrated portion 27 protruded above the fluorescent cover 12 ((h ) step). Various methods can be used for forming the fluorescent substance concentrating portion 27 by laminating the fluorescent substance L intensively in the center of the fluorescent substance cover 12 without spreading over the entire upper surface of the fluorescent substance concentrating portion 27 . For example, the liquid droplet of the fluorescent liquid, which is successively dropped to the fluorescent cover 12 by lengthening the liquid droplet ejection interval of the fluorescent liquid, is sequentially cured from the center of the fluorescent cover 12, whereby the phenomenon that the fluorescent liquid flows outward from the center of the fluorescent cover 12 . Or by using a fluorescent liquid having a high viscosity, the fluorescent liquid can be concentrated in the center of the fluorescent cover 12.

Typically, the intensity of light at the central portion of the LED element is greater than at other portions. Accordingly, by forming the fluorescent material concentration portion 27 at the center of the LED element 18 and increasing the concentration of the fluorescent material compared to other portions, the efficiency of the LED element 25 can be enhanced and a high-quality LED element can be manufactured.

6 shows that the fluorescent film 22 and the fluorescent substance concentration portion 27 are both provided on the fluorescent cover 12 but the fluorescent substance coating portion such as the EHD pump 100 shown in Fig. It is possible to make an LED element provided only with a fluorescent substance concentration on the fluorescent cover by using the apparatus.

Although the preferred embodiments of the present invention have been described above, the scope of the present invention is not limited to the embodiments described above.

For example, it has been shown in the drawing that a fluorescent cover 12 is attached to an LED chip 10 to form an LED element 18, and a fluorescent liquid L is applied thereon to form a fluorescent film 22 However, if the color coordinate value of the LED element 18 formed by attaching the fluorescent cover 12 to the LED chip 10 is equal to the target color coordinate value, the step of correcting the color coordinate value may be omitted.

In addition, in the step of attaching the fluorescent cover on the LED chip, a pickup tool having a structure other than the pickup tool 50 shown in Fig. 3 can be used.

Also, when a fluorescent liquid is used as an adhesive in the step of attaching the fluorescent cover on the LED chip, a fluorescent substance application device for applying a fluorescent substance on the LED element and correcting the color coordinate value of the LED element can be used. In this case, the EHD pump 100 shown in FIG. 4 or a device of another structure may be used as the fluorescence application device.

In addition, in addition to the EHD pump 100 shown in FIG. 4, various other devices capable of applying the fluorescent liquid on the fluorescent cover of the LED element are formed in the step of forming the fluorescent film on the fluorescent cover of the LED element by applying the fluorescent liquid on the LED element Can be used.

10: LED chip 12: fluorescent cover
14: Adhesive 18, 20, 25: LED element
22: Fluorescent film 27: Fluorescent substance concentration part
50: pick-up tool 52: pickup head
54: VCM lift actuator 56: rotary actuator
100: EHD pump 110: Voice coil motor
111: permanent magnet 112: coil
113: fixing member 114: elevating member
130: pump body 131:
132: inlet pipe 133: valve seat
120: valve rod 140: inlet valve
150: nozzle 170: power supply
180: control unit 200: work plate
L: Fluorescent liquid

Claims (8)

1. A method for manufacturing an LED element by forming a fluorescent layer on an LED chip,
(a) providing a plurality of LED chips separately provided on a wafer
(b) providing a plurality of fluorescent covers formed of a synthetic resin material mixed with a fluorescent material and covering the upper surface of the LED chip according to a mixing amount of the fluorescent material or a thickness of the fluorescent cover;
(c) measuring color coordinate values of the LED chip provided in the step (a);
(d) selecting a fluorescent cover capable of implementing a target color coordinate value by applying to the LED chip in which the color coordinate value is measured in the step (c), among the plurality of fluorescent covers; And
(e) attaching the fluorescent cover selected in the step (d) to the LED chip to form an LED element. The method according to claim 1,
(f) measuring a color coordinate value of the LED element formed in the step (e); And
(g) applying a fluorescent liquid mixed with a liquid synthetic resin and a fluorescent material powder onto the fluorescent cover of the LED element according to the color coordinate value of the LED element measured in the step (e) And correcting the light emitting diode according to the value of the light emitting diode. 3. The method of claim 2,
Wherein the step (g) comprises the steps of: storing the fluorescence solution; a nozzle provided below the storage part so as to discharge the fluorescence solution stored in the storage part downward; And a valve rod for applying a pressure to the fluorescent liquid stored in the portion of the pump body, a work plate on which the LED element is disposed, and an electric device electrically connected to the nozzle of the pump body and the LED element disposed on the work plate or the work plate. Wherein the fluorescent material is coated on the fluorescent cover of the LED element using an EHD pump including a fluorescent material in the nozzle and a power supply device for generating a potential difference between the LED element and the fluorescent material inside the nozzle. Way. The method of claim 3,
Wherein the EHD pump further comprises a voice coil motor (VCM) connected to a valve rod of the pump body to move the valve rod up and down. The method according to claim 3 or 4,
Wherein the step (e) comprises applying the fluorescent fluid of the storage portion onto the LED chip with the EHD pump, and attaching the fluorescent cover to the LED chip. The method according to claim 1,
(h) forming a bulb-shaped fluorescent material concentrator in the center of the LED device by applying a fluorescent material mixed with a liquid synthetic resin and a fluorescent material powder to the center of the LED device formed in the step (e) Wherein the light emitting device is a light emitting diode. The method according to claim 1,
Wherein the fluorescent cover and the LED chip are attached by applying a fluorescent liquid mixed with the liquid synthetic resin and the fluorescent material powder between the fluorescent cover and the LED chip. The method according to claim 1,
The step (e)
(e-1) applying an adhesive onto the LED chip,
(e-2) a step of picking up the fluorescent cover with a pick-up tool including a pick-up head for picking up the fluorescent cover and a VCM elevating actuator for picking up the pick-up head and pressing it onto the LED chip coated with the adhesive Wherein the step of forming the LED element comprises the steps of:

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