KR100721962B1 - Light-emitting device and Method of manufacturing the same - Google Patents

Abstract

The present invention provides a method of manufacturing a light emitting device comprising the steps of preparing a phosphor sheet comprising a phosphor and the step of providing the phosphor sheet on top of a light emitting diode chip and a light emitting device produced thereby.

The light emitting device and the method of manufacturing the same according to the present invention form a phosphor sheet having a predetermined thickness on the light emitting diode chip, thereby providing excellent color reproducibility and uniform color emission, and preventing light loss due to the phosphor to increase light efficiency. It can be made, there is an advantage that can implement a variety of desired colors.

Light emitting element, LED, phosphor, white light emission, light efficiency

Description

Light emitting device and method of manufacturing the same {Light-emitting device and Method of manufacturing the same}

1 and 2 are cross-sectional views showing a conventional light emitting device.

3A to 3C are cross-sectional views illustrating a manufacturing process of the first embodiment according to the present invention.

4A to 4D are cross-sectional views for explaining a manufacturing process of the second embodiment according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1, 10: substrate 2, 3, 20, 30: electrode

4, 40: light emitting diode chip 5, 50: reflector

6, 60: wire 7: phosphor

70 phosphor sheet 8, 80 molding part

The present invention relates to a light emitting device and a method for manufacturing the same, and more particularly, to form a sheet containing a phosphor on a light emitting diode chip to emit light of uniform color, to improve color reproducibility and to improve reliability. The present invention relates to a light emitting device and a method of manufacturing the same.

A light emitting diode (LED) refers to a device that makes a small number of carriers (electrons or holes) injected using a pn junction structure of a semiconductor and emits a predetermined light by recombination thereof, and red using GaAsP or the like. Green light emitting diodes using light emitting diodes, GaP and the like, and blue light emitting diodes using InGaN / AlGaN double hetero structure.

The light emitting device may implement white light by combining a light emitting diode chip and a phosphor of a compound semiconductor. This is achieved by attaching a phosphor emitting yellow green or yellow light as an excitation source on a part of the light emitting diode chip emitting blue light to obtain white color by blue light emission of the light emitting diode chip and yellow green light or yellow light emission of the phosphor. That is, white light can be realized by a combination of a blue light emitting diode chip made of a semiconductor component emitting a wavelength of 430 to 480 nm and a phosphor capable of generating yellow light using blue light as an excitation source.

In addition, a white phosphor may be obtained by applying a phosphor that is excited by ultraviolet light and emits visible light from blue to red on the light emitting diode chip emitting ultraviolet light. That is, the white light may be realized by a combination of a UV light emitting diode chip emitting a wavelength of 350 nm to 410 nm and a phosphor in which red, blue, and green light emitting characteristics are mixed in a constant ratio.

1 and 2 are cross-sectional views showing a conventional light emitting device.

Referring to the drawings, a light emitting device includes a substrate 1 having electrodes 2 and 3 formed thereon, a light emitting diode chip 4 mounted on the substrate 1, and a light emitting diode chip 4 surrounding the substrate. It comprises a reflector 5 formed on (1). The light emitting diode chip 4 is mounted on the first electrode 2 and electrically connected to the second electrode 3 through the wire 6. The reflector 5 includes a molding part 8 encapsulating the light emitting diode chip 4. It may also include a phosphor 7 for wavelength converting light from the light emitting diode chip 4 to achieve a desired color.

As shown in FIG. 1, a mixture of the phosphor 7 and the epoxy resin may be first doped onto the light emitting diode chip 4, and then a molding part 8 made of a transparent epoxy resin may be formed. However, in this case, it is difficult to quantify the phosphor at the correct position on the top of the LED chip, and the mixture of the phosphor and the resin to be doped is not uniform in the color of the light emitted from the LED chip depending on the shape of the doped color. Is easy to occur and the direction of light changes. In addition, there is a problem that the luminous efficiency is lowered due to the refraction of light between the doped mixture and the molding portion.

In addition, as shown in FIG. 2, the phosphor 7 may be evenly distributed in the molding part 8 encapsulating the light emitting diode chip 4. In this case, since the path between the LED chip and the phosphor is long, a large amount of phosphor should be included for efficient wavelength conversion. Loss of light occurs due to the large amount of phosphor distributed in the molding, which can cause a decrease in luminous efficiency.

In addition, such a molding part is formed by mixing a phosphor with a liquid epoxy resin, wherein the phosphor having a high specific gravity sinks downward due to a difference in specific gravity with a relatively low specific gravity epoxy while the liquid epoxy resin is cured. Due to the precipitation of the phosphor, a difference in concentration occurs in the liquid epoxy resin, and the light emitted from the light emitting diode chip is not constant, thereby causing a problem in color reproducibility, and color unevenness may occur.

In addition, since the phosphor is not uniformly distributed in the molding part, there is a problem in that the color of light emitted for each viewing angle of the light emitting diode is changed.

The present invention is to solve the above-described problems, by forming a phosphor sheet having a predetermined thickness on the light emitting diode chip can be excellent in color reproducibility and uniform color emission, and to prevent the loss of light due to the phosphor to improve the light efficiency An object of the present invention is to provide a light emitting device and a method of manufacturing the same, which can be increased and implement various desired colors.

In order to achieve the above object, the present invention provides a method of manufacturing a light emitting device comprising the steps of preparing a phosphor sheet comprising a phosphor and providing the phosphor sheet on top of a light emitting diode chip. .

The manufacturing of the phosphor sheet may include preparing a slurry by mixing the phosphor and a resin and forming the slurry into a sheet. After the forming of the slurry into a sheet, the sheet may further comprise the step of pressing and adhering on the heat-resistant film or glass. The slurry may be formed into a sheet by using a press molding method, an extrusion molding method, or a doctor blade method.

In addition, the preparing of the phosphor sheet may be characterized in that the mixture of the phosphor and the resin is applied to a heat resistant film or glass and cured.

In the preparing of the phosphor sheet on the light emitting diode chip, a plurality of phosphor sheets may be sequentially formed.

The present invention provides a light emitting device, which is manufactured as described above in the light emitting device including a light emitting diode chip and a phosphor. The light emitting diode chip may be a light emitting diode chip that emits blue light, and the phosphor may be a phosphor having yellow light emitting characteristics. The light emitting diode chip may be a light emitting diode chip that emits UV light, and the phosphor may be a phosphor having red, green, and blue light emitting characteristics.

Hereinafter, a light emitting device and a method of manufacturing the same will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you. Like numbers refer to like elements in the figures.

3A to 3C are cross-sectional views illustrating a manufacturing process of the first embodiment according to the present invention.

First, a phosphor and a resin are mixed to prepare a slurry. The resin is silicone resin, polyester resin, acrylic resin, epoxy resin, urethane resin, nylon resin, polyamide resin, polyimide resin, vinyl chloride resin, polycarbonate resin, polyethylene resin, teflon resin, polystyrene resin, polypropylene resin, Polyolefin resin and the like can be used. In this embodiment, a slurry is prepared by mixing a liquid epoxy resin and a phosphor. At this time, if necessary, it may further include an additive such as solvent. In addition, the slurry is not limited to the above liquid resin but may further include a solid resin.

The phosphor may mix not only one kind of phosphor but also a plurality of phosphors as necessary.

Using the slurry which is a mixture of the resin and the phosphor, a phosphor sheet 70 having a thickness of 10 μm to 5 mm is prepared as shown in FIG. 3A. The phosphor sheet 70 is manufactured by press molding the slurry into a sheet shape in a mold. In addition, the present invention is not limited thereto, and may be formed through various manufacturing processes such as an extrusion molding method and a doctor blade method.

Next, if necessary, as shown in FIG. 3B, the manufactured phosphor sheet 70 is cut into a desired size and shape using, for example, a sawing or scribing process. That is, cutting to a size of a predetermined region to be formed in the light emitting device, there is an advantage that can be formed in a size suitable for the light emitting device through a simple cutting process.

Referring to FIG. 3C, the light emitting device is formed by using the phosphor sheet 70 cut to the desired size. First, the light emitting diode chip 40 is configured to be electrically connected to the outside, and then the phosphor sheet 70 is formed on the light emitting diode chip 40.

In more detail, the electrodes 20 and 30 are formed on the substrate 10, and the electrodes corresponding to the positive electrode and the negative electrode of the LED chip 40 are separated from each other. The electrodes 20 and 30 may be formed on the substrate 10 through a printing technique using a metal material including copper or aluminum having excellent conductivity.

The LED chip 40 is mounted on the substrate 10 using various electrical mounting methods. The silver paste may be coated and mounted on the electrodes 20 and 30, or the light emitting diode chip 40 may be mounted on the upper portion of the substrate 10 using a non-conductive adhesive.

Thereafter, wire bonding is performed to electrically connect the LED chip 40 and the electrodes 20 and 30. At this time, as shown in the case of mounting the LED chip 40 having a positive electrode and a negative electrode on the upper and lower planes of the LED chip 40 on the electrode (20, 30) one wire 60 And connect the wires, and in the case of mounting the LED chip having the positive electrode and the negative electrode on the upper plane of the LED chip 40 on the substrate 10 instead of the electrodes 20 and 30, the two wires 60 ) To connect the LED chip 40 and the electrodes 20 and 30, respectively.

In order to improve the brightness of the light, the reflector 50 is formed to surround the LED chip 40 and have a predetermined slope on the inner wall.

The reflector 50 is filled with a transparent epoxy resin and the like to form a molding 80 by curing or semi-curing.

After the light emitting diode chip 40 is configured to be electrically connected to the outside, the above-described phosphor sheet 70 is formed on the light emitting diode chip 40. In this case, the phosphor sheet may be attached to the upper portion of the light emitting diode chip using an adhesive, or the phosphor sheet may be disposed on the upper portion of the light emitting diode chip using a UV curable resin, a thermosetting resin, a transparent sealant, or the like. . Alternatively, it may be attached using a compression method.

Although the phosphor sheet 70 is formed on the molding part 80 formed in the reflector 50 in the drawing, the present invention is not limited thereto and may be formed on the entire light emitting device. This can be easily adjusted in size in the process of cutting the above-described phosphor sheet 70. In addition, a plurality of phosphor sheets 70 may be sequentially formed on the light emitting diode chip 40 according to a desired purpose.

4A to 4D are cross-sectional views illustrating a manufacturing process of a second embodiment according to the present invention. This is almost the same as in the first embodiment, and is formed by adhering the phosphor sheet 70 to a separate heat resistant film 75 or glass. The description overlapping with the case of the first embodiment is omitted.

First, as shown in FIG. 4A, a phosphor sheet 70 is manufactured using a mixture slurry of phosphor and resin.

Referring to FIG. 4B, the phosphor sheet 70 is compressed and adhered to the heat resistant film 75. In addition, the phosphor sheet 70 may be pressed and adhered to glass such as soda-lime glass or quartz glass. In the drawing, the phosphor sheet 70 is first manufactured, and then pressed and adhered to the heat resistant film 75 or glass. However, the slurry including the phosphor may be coated on a heat resistant film and then cured. This can be done in various ways depending on the convenience and purpose of the process.

Next, as shown in FIG. 4C, the heat resistant film 75 or glass to which the phosphor sheet 70 is adhered is cut to a required size. That is, it can be cut to the size of a predetermined region to be formed in the light emitting device, and the phosphor sheet 70 can be easily formed in a size suitable for the light emitting device.

Referring to FIG. 4D, the light emitting device is formed by using the phosphor sheet 70 cut to the desired size.

In the light emitting device of the present invention as described above, the light emitting diode chip 40 and the phosphor sheet 70 may be variously selected to form a desired color. In order to implement white light emission, a blue light emitting diode chip emitting a wavelength of 430 to 480 nm is mounted, and a phosphor sheet manufactured by including a yellow light emitting phosphor is formed on the light emitting diode chip. At this time, blue light is emitted from the light emitting diode chip, and the blue light passes through a molding part formed of a transparent epoxy resin without loss of light due to a conventional phosphor or without being obstructed by a path. The blue light passing through the molding part is incident on the yellow light emitting phosphor sheet, and part of the incident light is wavelength-converted to yellow light. Blue light, which is part of the primary light emission, and yellow light wavelength-converted by the phosphor sheet may be mixed to implement white color. The degree of conversion can be adjusted by adjusting the phosphor concentration and distribution in the phosphor sheet or the thickness of the phosphor sheet.

In addition, to emit white light, a UV light emitting diode chip emitting a wavelength of 350 nm to 410 nm may be mounted, and a phosphor sheet including red, blue, and green light emitting phosphors may be formed on the light emitting diode chip. Alternatively, a phosphor sheet manufactured by including a blue light emitting phosphor, a green light emitting phosphor, and a red light emitting phosphor may be sequentially formed on the light emitting diode chip.

In the light emitting device of the present invention as described above, since the phosphor sheet is formed to a predetermined thickness on the light emitting diode chip, a uniform color is realized in comparison with the light emitting device including the phosphor which is mixed with the existing liquid epoxy resin and distributed unevenly. It has the advantage of improving reproducibility. In addition, the color variation can be reduced, and the color of light emitted can be made constant at every viewing angle of the light emitting diode.

In the related art, since a molding part is formed by mixing a liquid epoxy resin and a phosphor on a light emitting diode chip, light emitted from the light emitting diode chip passes through the molding part and is absorbed by the phosphor particles or canceled with each other by light emitted from the phosphor. Can be. However, the light emitting device according to the present invention forms a phosphor sheet having a predetermined thickness on the molding part encapsulating the light emitting diode chip, thereby reducing the loss of light emitted from the light emitting diode chip and increasing the light emission efficiency.

In addition, compared to the conventional incorporation of a large amount of phosphors for the uniform distribution of phosphors by manufacturing and forming a phosphor sheet of a certain thickness, it is possible to reduce the amount of phosphors used to reduce material costs and improve productivity There is this.

In addition, since the phosphor quantified through the above-described manufacturing process can be formed on the light emitting diode chip, a desired color can be more accurately realized, and a variety of colors can be realized by forming a phosphor sheet at a desired position through a simple process. There is an advantage.

The light emitting device of the present invention and a method of manufacturing the same are not limited to the above-described embodiments, but may be applied to products having various structures including phosphors.

The light emitting device and the method of manufacturing the same according to the present invention have the advantage of being able to emit light of uniform color and excellent color reproducibility by forming a phosphor sheet having a constant thickness on the light emitting diode chip. In addition, it is possible to increase the light efficiency by preventing the loss of light due to the phosphor, it can be easily formed in a desired position of the light emitting device to implement a variety of desired colors. In addition, the light emitting device and the method of manufacturing the same according to the present invention can reduce the amount of phosphor used, resulting in a material saving effect and contribute to the improvement of productivity.

Claims (9)

Mounting a light emitting diode chip on a substrate and forming a reflector to surround the light emitting diode chip; Forming a molding in the reflector; And And sequentially forming a plurality of phosphor sheets each including light emitting phosphors of different colors on the molding part. The method according to claim 1, Preparing the phosphor sheet, Preparing a slurry by mixing the phosphor and a resin; And Method of manufacturing a light emitting device comprising the step of forming the slurry into a sheet. The method according to claim 2, After the step of forming the slurry into a sheet, And pressing and adhering the sheet on a heat resistant film or glass. The method according to claim 2, Forming the slurry into a sheet, A method of manufacturing a light emitting device, characterized in that it is formed using any one of a press molding method, an extrusion molding method, or a doctor blade method. The method according to claim 1, Preparing the phosphor sheet, A mixture of the phosphor and the resin is applied to a heat resistant film or glass and cured. Mounting a light emitting diode chip emitting UV light on a substrate and forming a reflector to surround the light emitting diode chip; Forming a molding in the reflector; And And sequentially forming phosphor sheets prepared on the molding part, the phosphor sheets including blue light emitting phosphors, green light emitting phosphors, and red light emitting phosphors, respectively. Board; A light emitting diode chip mounted on the substrate; A reflector formed on the substrate to surround the light emitting diode chip; A molding part formed in the reflector; And A light emitting device comprising a plurality of phosphor sheets including light emitting phosphors of different colors sequentially formed on the molding portion. delete The method according to claim 7, The light emitting diode chip is a light emitting diode chip that emits UV light, and the plurality of phosphor sheets each include a red light emitting phosphor, a green light emitting phosphor, and a blue light emitting phosphor.

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