KR20090102121A - Menufacturing method of light emitting device - Google Patents

Abstract

PURPOSE: A method for manufacturing a light emitting device is provided to reduce a size in comparison with a lead frame type light emitting device. CONSTITUTION: A substrate is prepared. The substrate includes first and second wiring structure(13a), one window or more, and first and second main surfaces. The first and second wiring structures are parallel in the length direction. One window or more are formed between the first and second wiring structures. The first and second main surfaces are opened by the window and face each other. An adhesive sheet is attached to the second main surface. One light emitting diode chip or more including the first and second electrodes are attached to the adhesive sheet to be arranged in the window. A resin part(14) is formed in the window to cover the light emitting diode chip. The adhesive sheet is removed from the substrate and the light emitting diode chip. A phosphor layer(15) is formed on a side of the light emitting diode chip exposed by removing the adhesive sheet. A part of the phosphor layer is removed so that the light passing through the phosphor layer obtains the required chromaticity.

Description

Light emitting device manufacturing method {Menufacturing Method of Light Emitting Device}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a light emitting device, and more particularly, to a method of manufacturing a light emitting device that can be used in a side view type backlight unit having a semiconductor light emitting diode chip.

In general, as a light emitting device having a light emitting diode chip, a light emitting device structure having a case in which a white resin is injection molded into a lead frame is widely used. Such a light emitting device mounts an LED chip so as to be connected to a lead frame in a groove part of a case, and then fills the groove part with resin. In particular, in order to manufacture a white light emitting device, a method of containing the phosphor powder in the resin filled in the groove portion can be used.

However, the conventional light emitting device structure has some disadvantages in terms of miniaturization and yield.

For example, in the case of a side view type light emitting device that can be surface mounted mainly used as a light source for a backlight of a display portion of a mobile phone, a thinning of the side light emitting device is also required according to the thinning of a mobile phone. have. However, in the conventional light emitting device structure, since the groove portion is to be provided for mounting the LED chip, there is a difficulty in manufacturing the case having it sufficiently miniaturized.

In addition, after the injection molding of the case together with the lead frame, a complicated process of mounting the LED chip and providing the resin packaging portion to the groove portion, there is a problem that the yield is lowered and the process cost is increased.

Particularly, in the conventional white light emitting device, chromatic dispersion may be uneven due to the dispersion of the phosphor filling amount by the dispenser during the dispensing of the liquid resin containing the phosphor powder in the groove portion.

The present invention is to solve the above problems, an object of the present invention is to provide a method of manufacturing a light emitting device that is smaller than the lead frame type light emitting device, and can be easily manufactured.

Further, another object of the present invention is to provide a light emitting device manufacturing method which can easily obtain a desired chromaticity when the light emitting device emits white light.

In order to achieve the above object, one embodiment of the present invention,

First and second wiring structures disposed parallel to each other in the longitudinal direction, at least one window formed between the first and second wiring structures, and first and second main surfaces opened by the windows and opposed to each other; Providing a substrate, attaching an adhesive sheet to the second main surface, and providing at least one light emitting diode chip having first and second electrodes, each of which is disposed on the window. Attaching, electrically connecting the first and second wiring structures and the first and second electrodes, respectively, forming a resin portion in the window to cover the light emitting diode chip, and the substrate And removing the adhesive sheet from the light emitting diode chip, and forming a phosphor film on the exposed surface of the light emitting diode chip by removing the adhesive sheet. Is emitted from the LED chip provides a light emitting device manufacturing method comprising the step of removing the phosphor film portion of light passing through the fluorescent material film to have a desired color value.

Preferably, the window and the light emitting diode chip are a plurality, in this case, the plurality of windows may be formed spaced apart from each other in the longitudinal direction of the substrate. Furthermore, the plurality of light emitting diode chips may be arranged on one straight line.

On the other hand, the plurality of light emitting diode chips may be connected in parallel to each other.

In a preferred embodiment of the invention, the substrate may be a flexible substrate, specifically, a liquid crystal polymer (LCP) substrate.

Preferably, the first and second wiring structures may be electrode patterns formed on the first main surface.

The first and second electrodes may be formed on one surface of the light emitting diode chip, and the light emitting diode chip may be disposed on the window such that the electrode forming surface faces the thickness direction of the substrate.

In this case, the first and second wiring structures may be electrode patterns formed on the first main surface, and the LED chip may be disposed on the window so that the electrode forming surface faces the same direction as the first main surface. .

In addition, the step of electrically connecting the first and second wiring structures and the first and second electrodes, respectively, is preferably performed by wire bonding. In this case, the forming of the resin part may be performed so that the resin part covers up to the wire.

The forming of the resin part may be performed so that the resin part covers the remaining surfaces of the light emitting diode chip except for the surface opposite to the electrode forming surface.

On the other hand, the step of removing a portion of the phosphor film is preferably performed by the blade.

In a preferred embodiment of the present invention, before removing the portion of the phosphor film, the method may further include measuring the chromaticity of light emitted from the light emitting diode chip and passed through the phosphor film. In this case, it is preferable that the step of measuring the chromaticity and the step of removing a part of the phosphor film alternately are performed multiple times.

Preferably, the resin part may be made of a white resin, and specifically, may be made of a white resin including TiO ₂ .

Preferably, the first and second wiring structures may have connection portions connected to the first and second electrodes, respectively.

On the other hand, the adhesive sheet is provided with a curable liquid resin applied to one surface, the step of attaching the adhesive sheet to the substrate and the step of attaching the light emitting diode chip to the adhesive sheet is irradiated with ultraviolet rays to the adhesive sheet It can be carried out by curing the curable liquid resin.

As described above, according to the present invention, a method of manufacturing a light emitting device that is smaller than the lead frame type light emitting device and can be easily manufactured can be obtained.

Further, according to the present invention, when the light emitting device emits white light, a light emitting device manufacturing method capable of easily obtaining a desired chromaticity can be obtained.

1A and 1B show a light emitting device manufactured by a method of manufacturing a light emitting device according to an embodiment of the present invention, in which FIG. 1A corresponds to a shape viewed from above and FIG. 1B corresponds to a shape viewed from a side direction.

FIG. 2 is an enlarged view of the area A1 around the LED chip in FIG. 1A, and the right side shows the shape viewed from the side.

3 is an enlarged view of the area A2 around the LED chip in FIG. 1B.

4A to 4F are cross-sectional views illustrating a method of manufacturing a light emitting device according to an embodiment of the present invention.

5 is a plan view schematically illustrating a backlight unit employing a light emitting device according to the present invention.

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

11: light emitting diode chip 11a, 11b: first and second electrodes

12: LCP substrate 13a, 13b: first and second wiring structure

14: resin portion 15: phosphor film

W: Window Z: Zener Diode

40: adhesive sheet 100: light receiving device

200: blade 51: light guide plate

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for clarity, and the elements denoted by the same reference numerals in the drawings are the same elements.

1A and 1B show a light emitting device manufactured by a method of manufacturing a light emitting device according to an embodiment of the present invention, in which FIG. 1A corresponds to a shape viewed from above and FIG. 1B corresponds to a shape viewed from a side direction.

1A and 1B, the light emitting device 10 according to the present embodiment includes a liquid crystal polymer (LCP) substrate, a plurality of light emitting diode chips L, a resin part, a phosphor film, and a zener. The diode Z is comprised.

In this case, the LCP substrate has first and second wiring structures arranged in parallel in the length (l) direction, and a plurality of windows W are formed between the first and second wiring structures. Here, the window (W) is provided as a space for the arrangement of the light emitting diode chip, the light emitting diode chip (L) is the window so that the light extraction surface and the electrode forming surface opposite thereto the direction of the thickness of the LCP substrate (W) is disposed. More details on this will be described later.

In the present embodiment, the substrate used for the light emitting device 10 is used as a flexible substrate, particularly an LCP substrate, in order to enhance stability and flexibility in the light emitting device having a long length in one direction. That is, since ceramic substrates and the like generally used for mounting the LED chip have limitations in manufacturing into an elongated shape, it is preferable to use a flexible substrate such as an LCP substrate when used in a light emitting device as in the present embodiment. desirable. By using the flexible LCP substrate as described above, in addition to the shape of FIG. 1 of the light emitting device, there are advantages in that the shape of the light emitting device can be variously modified.

In addition, LCP is suitable as a PCB material because of its excellent electrical properties, low hygroscopicity and low rate of dimensional change. In particular, LCP has a heat resistance of about 280 ° C, which is somewhat inferior in heat resistance to polyimide (PI) having a heat resistance of about 300 ° C. Is low.

In addition to these advantages, LCP has excellent electrical insulation properties, is relatively stable to solvents such as acids and alkalis, has a low melt viscosity, and is easy to mold and can be formed to a thin thickness.

However, according to the embodiment, other materials having flexibility besides LCP, for example, FR-4, BT resin, or the like, may be used as the substrate. In addition, although it is preferable to use a flexible substrate as described above, in other embodiments, a general PCB substrate may be used instead of the flexible substrate.

On the other hand, as described above, the light emitting device 10 is a structure in which a plurality of light emitting diode chips are arranged in the longitudinal direction on one substrate, it can be easily used for a side view type backlight. That is, as will be described later, compared to the case of mounting each light emitting package in a conventional side view type backlight, it can be manufactured more easily, and furthermore, the height of the light emitting surface of the light emitting diode chip can be made uniform, so that the luminance distribution The uniformity of can be improved.

The zener diode Z may be provided to prevent electrostatic discharge, and may be connected in parallel with other light emitting diode chips as described below. However, in some embodiments, the zener diode Z may not be included in the light emitting device 10.

In the present embodiment, the light emitting device 10 includes five light emitting diode chips L and one zener diode Z, the size of which is 30 mm x 0.4 mm x 1.0 mm. Here, the numerical values correspond to the length l, the height h, and the thickness d, respectively.

As such, when the light emitting device 10 is used for a side view type backlight, the height h of about 0.4 mm may contribute to thinning of the backlight as compared with a conventional lead frame type light emitting device.

In addition, the light emitting device 10 may be manufactured by forming a window W of the LCP substrate, arranging a light emitting diode chip in the window W, and then filling a white resin, thereby providing a plurality of light emitting diodes. The heights of the light extraction surfaces of the chips can be uniform to each other. Accordingly, in the case of the backlight unit employing the light emitting device 10, it is expected to improve the uniformity of the luminance distribution.

In the present embodiment, the light emitting device 10 consisting of five light emitting diode chips has been described as an example. However, the number of light emitting diode chips may be appropriately adjusted as necessary, and although not separately illustrated, only one light emitting diode chip is included. The light emitting device may also be implemented. Furthermore, as described above, the shape of the light emitting device may also be modified as necessary, such as a rectangle or a circle, rather than a bar type, as shown in FIGS. 1A and 1B.

Hereinafter, elements constituting the light emitting device will be described in detail with reference to FIGS. 2 and 3.

FIG. 2 is an enlarged view of the area A1 around the LED chip in FIG. 1A, and the right side shows the shape viewed from the side. 3 is an enlarged view of the area A2 around the light emitting diode chip L in FIG. 1B.

2 and 3, in the light emitting device according to the present embodiment, the light emitting diode chip 11 includes first and second electrodes 11a and 11b and the first and second electrodes. The surface on which the 11a, 11b is formed is arrange | positioned at the window W of the LCP board | substrate 12 so that it may face the resin part 14. As shown in FIG.

In this case, the light emitting diode chip 11 corresponds to the light extraction surface mainly on the surface opposite to the electrode formation surface. In the present specification, the term “light extraction surface” may be understood as a surface facing the surface on which the first and second electrodes 11a and 11b are formed as a direction in which light is mainly emitted from the LED chip 12. Can be. That is, in the light emitting diode chip 11 employed in the present embodiment, the first and second electrodes 11a and 11b are formed on the same surface, and the light emitted from the active layer is mainly emitted to the opposite surface. .

In the present embodiment, the phosphor film 15 is formed on the light extraction surface for white light emission, and the phosphor film has a structure in which phosphor particles are dispersed in a transparent resin. For example, if the LED chip 11 emits blue light and the phosphor particles include a yellow fluorescent material, the light emitting device may emit white light. In this case, it may be understood by those skilled in the art that white light emission is possible by appropriately adjusting the emission wavelength of the light emitting diode chip 11 and the fluorescent material.

On the other hand, as will be described later, the light emitted from the light emitting diode chip 11 and passed through the phosphor film 15 has a chromaticity value close to natural white light (for example, when chromaticity coordinates are (0.3, 0.3)). In order to obtain the thickness (t) of the phosphor film 15 may be appropriately adjusted during the manufacturing process.

The resin part 14 fills the inside of the window W to fix the light emitting diode chip 11 to the window W, and further, protects the light emitting diode chip 11.

As shown in FIG. 3, in the present embodiment, the resin part 14 is formed to cover the remaining surfaces except for the surface facing the electrode forming surface of the light emitting diode chip 11. As described above, the phosphor film 15 is formed on the surface opposite to the electrode forming surface.

In general, although the window may be filled with a transparent resin that may be employed, the resin part 14 may be made of a white resin. This is because it is important to reduce the amount of light emitted in the direction of the electrode formation surface of the light emitting diode chip 11 in order to improve the luminous efficiency. Therefore, when the resin portion 14 is made of white resin, most of the light emitted from the light emitting diode chip 11 and directed toward the resin portion 14 may be reflected and guided toward the light extraction surface. An improvement in efficiency can be expected.

In this case, the thickness of the resin part 14 may be appropriately adjusted in consideration of a reflection function and a space disposed in the backlight. In the present embodiment, as described above, the resin part 14 and the LCP substrate ( 12) was added so that the total thickness (thickness indicated by d in FIG. 1) was 1.0 mm.

Meanwhile, the present invention is not limited thereto, but in the present embodiment, a silicone resin including TiO ₂ is employed as the white resin forming the resin part 14, and other materials having high light reflectance may be employed.

First and second wiring structures 13a and 13b disposed on the LCP substrate 12 are electrically connected to the electrodes 11a and 11b of the light emitting diode chip 11, respectively. Power on

The first and second wiring structures 13a and 13b correspond to electrode patterns formed on both sides of the LCP substrate 12 in parallel with each other along the length direction of the LCP substrate 12, and a part of the LCP substrate 12 may be formed of Au or the like. It can be obtained by plating. In this case, in order to obtain an efficient connection structure with the first and second electrodes 11a and 11b, the first and second wiring structures 13a and 13b are connected to the first and second electrodes 11a and 11b. It is preferable to be formed in the same direction. Furthermore, as shown in FIG. 2, the first and second wiring structures 13a and 13b may have connection portions C, respectively. In addition, the connection part C and the first and second electrodes 11a and 11b may be electrically connected by a wire made of Au or the like. In this case, the resin part 14 may have such a wire bonding structure and the It is preferable that the LCP substrate 12 is formed so as to cover the surface (first main surface) on which the first and second wiring structures 13a and 13b are formed.

As described above, the light emitting device can reduce the size and manufacturing cost of the light emitting device such as a conventional lead frame package, and can mount the light emitting diode chip at a uniform height to improve the uniformity of the luminance distribution. It is possible to minimize the occurrence of the dark portion due to the space between the diode chips. In addition, it is possible to easily obtain a light emitting device having a desired chromaticity value by adjusting the thickness of the phosphor film for providing white light.

Hereinafter, the method of manufacturing the above-described light emitting device will be described with reference to FIGS. 4A to 4F. 4A to 4F are cross-sectional views illustrating a method of manufacturing a light emitting device according to an embodiment of the present invention.

First, as shown in Figure 4a, the adhesive sheet 40 is attached to the lcp substrate 12. As described above, the lcp substrate 12 has a wiring structure 13a and one or more windows W. As shown in FIG. In this case, although not shown in FIG. 4A, the wiring structure may include the first wiring structure 13a and the second wiring structure arranged in the longitudinal direction of the lcp substrate 12, as shown in FIG. 2. City).

The adhesive sheet 40 may be adhered to the lcp substrate 12 by applying a curable liquid resin to the upper surface and curing the curable liquid resin by ultraviolet irradiation.

Next, as shown in FIG. 4B, the LED chips 11 are positioned in the window W, and then attached to the adhesive sheet 40. In this case, the above-described process of attaching the lcp substrate 12 and the adhesive sheet 40 may be performed simultaneously with the process of attaching the LED chip 11. After attaching the LED chip 11, the LED chip 11 and the wiring structure are electrically connected by wire bonding. In this case, the light emitting diode chip 11 is attached to the light extraction surface toward the adhesive sheet 40, so that the electrode forming surface is toward the wiring structure forming surface of the lcp substrate 12.

Meanwhile, a more detailed connection relationship between the light emitting diode chip 11 and the wiring structure is the same as that shown in FIGS. 2 and 3.

Subsequently, as illustrated in FIG. 4C, a resin part filling at least an inner region of the window W is formed to cover the LED chip 11 and the wire bonding structure. As described above, the resin part 14 fixes the light emitting diode chip 11 in the window W, and is a white resin containing TiO ₂ , which reflects light emitted from the light emitting diode chip 11. Function can be performed.

The resin portion 14 may be formed by a method of molding a resin containing TiO ₂ using a metal mold and curing, or a method such as molding by screen printing using a metal mask and curing.

Next, as shown in FIG. 4D, after the removal, the phosphor film 15 is formed on the removed LED chip 11 surface. As described above, the phosphor film 15 is provided to absorb white light emitted from the light emitting diode chip 11 and convert the wavelength thereof so as to enable white light emission. It is a structure formed by being dispersed.

In the present embodiment, the phosphor films 15 formed on the light emitting diode chips 11 are connected to each other. Alternatively, as shown in FIGS. 1 and 3, the phosphor film 15 forming region is formed on the light emitting diode chips. The light extraction surface of (11) and its peripheral area can be limited. On the other hand, in consideration of the process of adjusting the chromaticity by removing a portion of the phosphor film, it is preferable that the thickness of the phosphor film 15 is formed to be somewhat thicker than the thickness to be employed in the final light emitting device. Specifically, the thickness of the phosphor film 15 before the chromaticity adjustment process to be described later to have a range of about 50 ~ 80㎛.

On the other hand, the method of forming the phosphor film 15 may be a method of forming the resin portion 14, that is, a method of molding by molding or screen printing, and then curing.

Next, the thickness of the phosphor film 15 is adjusted so that the light emitted from the light emitting device manufactured by the above method has a desired chromaticity value.

More specifically, this will be described in detail. First, as shown in FIG. 4E, the light-receiving device (e.g., light emitted from the light-emitting diode chip 11 and passed through the phosphor film 15), as shown in FIG. The chromaticity is measured by positioning 100). Here, if the measured chromaticity value is close to the range of the desired chromaticity coordinates, e.g., (0.3, 0.3), the subsequent process is no longer required, but otherwise, the phosphor film 15 has a desired chromaticity value. It is necessary to adjust the thickness. That is, the chromaticity value of the light emitted to the outside varies depending on the thickness of the phosphor film 15, and by adjusting this, a desired chromaticity can be obtained. That is, this step may be referred to as a chromaticity correction step of the light emitting device.

In this case, the thickness control of the phosphor film 15 is performed by removing a portion thereof using the blade 200 or the like as shown in FIG. 4F, and then measuring chromaticity and removing the phosphor film 15 according to the result. It can be done by repeating.

After completing the above-described chromaticity correction step for one light emitting diode chip, the thickness of each phosphor film is adjusted using a light receiving device and a blade with another light emitting diode chip. However, according to the exemplary embodiment, the chromaticity correction step may be performed at one time by including the same number of light receiving devices and blades as the number of light emitting diode chips. As described above, in the light emitting device manufacturing method according to the present embodiment, chromaticity around each light emitting diode chip can be easily adjusted individually in the light emitting device having a plurality of light emitting diode chips.

5 is a plan view schematically illustrating a backlight unit employing a light emitting device according to the present invention.

The light emitting device employed in the backlight unit corresponds to the light emitting device described in FIG. 1 in the above-described embodiment. In this case, the backlight unit may be used as a backlight such as an LCD panel, and may also be used as a white lighting device.

Referring to FIG. 5, the light emitting device is mounted to the backlight unit to be in a side view type. In addition, the backlight unit includes a light guide plate 51 disposed on a path of light emitted from the light emitting device, and first and second wiring structures 52a and 52b electrically connected to the wiring structure of the light emitting device.

The present invention is not limited by the above-described embodiment and the accompanying drawings, but is intended to be limited by the appended claims. Accordingly, various forms of substitution, modification, and alteration may be made by those skilled in the art without departing from the technical spirit of the present invention described in the claims, which are also within the scope of the present invention. something to do.

Claims (20)

First and second wiring structures disposed parallel to each other in the longitudinal direction, at least one window formed between the first and second wiring structures, and first and second main surfaces opened by the windows and opposed to each other; Providing a substrate; Attaching an adhesive sheet to the second main surface; Attaching at least one light emitting diode chip having first and second electrodes to the adhesive sheet such that each is disposed in the window; Electrically connecting the first and second wiring structures and the first and second electrodes, respectively; Forming a resin part in the window to cover the light emitting diode chip; Removing the adhesive sheet from the substrate and the light emitting diode chip, and forming a phosphor film on the exposed surface of the light emitting diode chip by removing the adhesive sheet; And Removing a portion of the phosphor film such that light emitted from the light emitting diode chip and passing through the phosphor film has a desired chromaticity value; Light emitting device manufacturing method comprising a. The method of claim 1, And a plurality of the window and the light emitting diode chip. The method of claim 2, And the plurality of windows are formed to be spaced apart from each other by a predetermined distance in the longitudinal direction of the substrate. The method of claim 3, And a plurality of light emitting diode chips arranged on one straight line. The method of claim 2, And a plurality of light emitting diode chips connected in parallel with each other. The method of claim 1, The substrate is a light emitting device manufacturing method, characterized in that the flexible substrate. The method of claim 6, And said substrate is a liquid crystal polymer (LCP) substrate. The method of claim 1, Wherein the first and second wiring structures are electrode patterns formed on a first main surface. The method of claim 1, The first and second electrodes are formed on one surface of the light emitting diode chip, And the light emitting diode chip is disposed in the window such that the electrode forming surface faces the thickness direction of the substrate. The method of claim 9, The first and second wiring structures are electrode patterns formed on the first main surface. And the light emitting diode chip is disposed in the window such that the electrode forming surface faces the same direction as the first main surface. The method of claim 10, And electrically connecting the first and second wiring structures and the first and second electrodes, respectively, by wire bonding. The method of claim 11, Forming the resin portion is performed so that the resin portion covers the wire. The method of claim 9, The forming of the resin part may include performing a resin part covering the remaining surfaces of the light emitting diode chip except for the surface opposite to the electrode forming surface. The method of claim 1, Removing the part of the phosphor film is performed by a blade. The method of claim 1, Before removing the portion of the phosphor film, measuring the chromaticity of light emitted from the light emitting diode chip and passing through the phosphor film. The method of claim 15, Measuring the chromaticity and removing a portion of the phosphor film are alternately performed in a plurality of times. The method of claim 1, The resin part manufacturing method of a light emitting device, characterized in that made of white resin. The method of claim 17, The resin unit comprises a TiO ₂ manufacturing method of the light emitting device. The method of claim 1, And the first and second wiring structures have connection portions connected to the first and second electrodes, respectively. The method of claim 1, The adhesive sheet is provided with a curable liquid resin applied to one surface, Attaching an adhesive sheet to the substrate and attaching the light emitting diode chip to the adhesive sheet are performed by curing ultraviolet light on the adhesive sheet to cure the curable liquid resin.