KR101623558B1 - Light emitting device package and its manufacturing method - Google Patents

Abstract

The present invention relates to a light emitting device package and a method of manufacturing the same, which can improve productivity by improving light uniformity, improving light uniformity, reducing manufacturing cost and manufacturing time, ; A light emitting element mounted on the substrate; And a reflective wall provided on the substrate and surrounding the side surface of the light emitting device along the surface of the side surface of the light emitting device.

Description

TECHNICAL FIELD The present invention relates to a light emitting device package and a manufacturing method thereof,

The present invention relates to a light emitting device package and a method of manufacturing the same. More specifically, the present invention relates to a light emitting device package and a method of manufacturing the same, And a method of manufacturing the same.

A light emitting diode (LED) is a kind of semiconductor device that can emit light of various colors by forming a light emitting source through the formation of a PN diode of a compound semiconductor. Such a light emitting device has a long lifetime, can be reduced in size and weight, has a strong directivity of light, and can be driven at a low voltage. Further, such an LED is resistant to impact and vibration, does not require preheating time and complicated driving, can be packaged in various forms, can be modularized for various purposes, and can be applied to various lighting devices and display devices.

The direct-type light emitting device package widely used in the backlight unit can widely disperse light generated from the light emitting device package through the secondary lens so as to reduce the thickness of the unit and uniformly irradiate the light to the light guide plate.

However, in the conventional light emitting device package, the light generated from the light emitting device package is dispersed too much in four directions, so light control through the secondary lens is difficult, and the rim- A complicated phenomenon such as refraction of light, interference, or spectroscopic phenomenon occurs in the lens, and there is a problem that a color deviation or a lightness deviation of light irradiated to the light guide plate occurs severely.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above problems and it is an object of the present invention to improve the directivity of light by using a reflective wall surrounding a side surface of a light emitting device, It is possible to reduce unnecessary light refraction, interference, and spectroscopic phenomenon by reducing light, thereby reducing the color deviation and lightness deviation of the light irradiated to the light guide plate, reducing the production cost and the manufacturing time, And an object of the present invention is to provide a device package and a manufacturing method thereof. However, these problems are exemplary and do not limit the scope of the present invention.

According to an aspect of the present invention, there is provided a light emitting device package including: a light emitting element; And a reflection wall that surrounds the side surface of the light emitting device so as to prevent light emission in a lateral direction of the light emitting device.

Further, according to the idea of the present invention, the reflection wall can directly contact the side surface of the light emitting element.

According to an aspect of the present invention, the reflective wall may be formed by selecting at least one of EMC including at least one reflective material, white silicon containing reflective material, PSR, and combinations thereof.

According to an aspect of the present invention, the light emitting element is in the form of a rectangular plate, and the reflective wall surrounds the vertical side of the light emitting element, and a square hole is formed in direct contact with the vertical side of the light emitting element have.

According to an aspect of the present invention, the light emitting device package further includes a substrate on which the light emitting device is mounted, and the reflective wall may be provided on the substrate.

According to an aspect of the present invention, the reflective wall may be dispensed or screen printed on the substrate and the light emitting element.

According to an aspect of the present invention, the substrate may be formed by selecting at least one of a lead frame, a PCB, a FPCB, and a combination thereof.

In addition, the light emitting device package according to the present invention may further include a phosphor disposed in an optical path of the light emitting device.

Further, according to an aspect of the present invention, the light emitting element may be a flip chip.

According to an aspect of the present invention, there is provided a method of manufacturing a light emitting device package, including: preparing a substrate strip; Placing at least one light emitting device on the substrate strip; And providing a reflective wall surrounding the side surface of the light emitting device along the surface of the side surface of the light emitting device.

According to an aspect of the present invention, the step of providing the reflective wall may be a step of dispensing or screen printing the reflective wall on the side of the substrate strip and the light emitting element.

According to some embodiments of the present invention as described above, it is possible to improve the light distribution performance, reduce the color discrepancy and the lightness variation of light, reduce manufacturing cost and production time, . Of course, the scope of the present invention is not limited by these effects.

1 is a cross-sectional view conceptually showing a light emitting device package according to some embodiments of the present invention.
2 is a perspective view showing the light emitting device package of FIG.
FIG. 3 is a light distribution diagram showing a light distribution curve according to the directivity angle of the light emitting device package of FIG. 1;
4 is a cross-sectional view illustrating a state in which a lens is mounted on the light emitting device package of FIG.
5 is a light distribution diagram showing a light distribution curve according to a directivity angle in a state where a lens is installed in the light emitting device package of FIG.
6 to 9 are cross-sectional views illustrating steps of a method of manufacturing a light emitting device package according to some embodiments of the present invention.
10 is a flowchart showing a method of manufacturing a light emitting device package according to some embodiments of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified in various other forms, The present invention is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will fully convey the concept of the invention to those skilled in the art. In the drawings, the thickness and size of each layer are exaggerated for convenience and clarity of explanation.

It is to be understood that throughout the specification, when an element such as a film, region or substrate is referred to as being "on", "connected to", "laminated" or "coupled to" another element, It will be appreciated that elements may be directly "on", "connected", "laminated" or "coupled" to another element, or there may be other elements intervening therebetween. On the other hand, when one element is referred to as being "directly on", "directly connected", or "directly coupled" to another element, it is interpreted that there are no other components intervening therebetween do. Like numbers refer to like elements. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items.

Although the terms first, second, etc. are used herein to describe various elements, components, regions, layers and / or portions, these members, components, regions, layers and / It is obvious that no. These terms are only used to distinguish one member, component, region, layer or section from another region, layer or section. Thus, a first member, component, region, layer or section described below may refer to a second member, component, region, layer or section without departing from the teachings of the present invention.

Also, relative terms such as "top" or "above" and "under" or "below" can be used herein to describe the relationship of certain elements to other elements as illustrated in the Figures. Relative terms are intended to include different orientations of the device in addition to those depicted in the Figures. For example, in the figures the elements are turned over so that the elements depicted as being on the top surface of the other elements are oriented on the bottom surface of the other elements. Thus, the example "top" may include both "under" and "top" directions depending on the particular orientation of the figure. If the elements are oriented in different directions (rotated 90 degrees with respect to the other direction), the relative descriptions used herein can be interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" include singular forms unless the context clearly dictates otherwise. Also, " comprise "and / or" comprising "when used herein should be interpreted as specifying the presence of stated shapes, numbers, steps, operations, elements, elements, and / And does not preclude the presence or addition of one or more other features, integers, operations, elements, elements, and / or groups.

Hereinafter, embodiments of the present invention will be described with reference to the drawings schematically showing ideal embodiments of the present invention. In the figures, for example, variations in the shape shown may be expected, depending on manufacturing techniques and / or tolerances. Accordingly, the embodiments of the present invention should not be construed as limited to the particular shapes of the regions illustrated herein, but should include, for example, changes in shape resulting from manufacturing.

FIG. 1 is a cross-sectional view conceptually showing a light emitting device package 100 according to some embodiments of the present invention, and FIG. 2 is a perspective view showing the light emitting device package 100 of FIG.

1 and 2, a light emitting device package 100 according to some embodiments of the present invention includes a substrate 10, a light emitting device 20, and a reflective wall 30 can do.

The substrate 10 can receive the light emitting device 20 and is electrically connected to the light emitting device 20. The substrate 10 may have appropriate mechanical strength and insulation property to support the light emitting device 20, Or a conductive material.

For example, the substrate 10 may include various wiring layers to connect the light emitting device 20 with an external power source, and may include a printed circuit board (PCB) having a plurality of epoxy resin sheets formed thereon, Lt; / RTI > The substrate 10 may be a Flexible Printed Circuit Board (FPCB) made of a flexible material.

In addition, the substrate 10 may be a synthetic resin substrate such as a resin or a glass epoxy or a ceramic substrate in consideration of a thermal conductivity. In addition, the substrate 10 may be formed of an insulating material such as aluminum, copper, zinc, tin, A metal substrate such as silver can be applied, and a plate or a lead frame substrate can be applied.

In addition, the light emitting device 20 may be mounted on the substrate 10, and may be formed of a semiconductor. For example, LEDs of blue, green, red, and yellow light emission, and LEDs of ultraviolet light emission, which are made of a nitride semiconductor, can be applied. The nitride semiconductor is represented by a general formula Al _x Ga _y In _z N (0? X? 1, 0? Y? 1, 0? Z? 1, x + y + z = 1).

The light emitting device 20 can be formed by epitaxially growing nitride semiconductors such as InN, AlN, InGaN, AlGaN, and InGaAlN on a sapphire substrate for growth or a silicon carbide substrate by a vapor phase growth method such as MOCVD To grow. The light emitting device 20 may be formed using semiconductors such as ZnO, ZnS, ZnSe, SiC, GaP, GaAlAs, and AlInGaP in addition to the nitride semiconductor. These semiconductors can be stacked in the order of an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer. The light emitting layer (active layer) may be a laminated semiconductor having a multiple quantum well structure or a single quantum well structure or a laminated semiconductor having a double hetero structure. In addition, the light emitting device 20 can be selected to have an arbitrary wavelength depending on the application such as display use and illumination use.

Here, as the growth substrate, an insulating, conductive or semiconductor substrate may be used if necessary. For example, the growth substrate may be sapphire, SiC, Si, MgAl 2 O 4, MgO, LiAlO 2, LiGaO 2, GaN. A GaN substrate, which is a homogeneous substrate, is preferable for epitaxial growth of a GaN material, but a GaN substrate has a problem of high production cost due to its difficulty in manufacturing.

Sapphire and silicon carbide (SiC) substrates are mainly used as the different substrates. Sapphire substrates are more utilized than expensive silicon carbide substrates. When using a heterogeneous substrate, defects such as dislocation are increased due to the difference in lattice constant between the substrate material and the thin film material. Also, due to the difference in the thermal expansion coefficient between the substrate material and the thin film material, warping occurs at a temperature change, and warping causes a crack in the thin film. This problem may be reduced by using the buffer layer 1502 between the substrate 1501 and the light emitting stacked body S which is GaN-based.

In addition, the substrate for growth may be completely or partially removed or patterned in order to improve the optical or electrical characteristics of the LED chip before or after the growth of the LED structure.

For example, in the case of a sapphire substrate, the substrate can be separated by irradiating the laser to the interface with the semiconductor layer through the substrate, and the silicon or silicon carbide substrate can be removed by a method such as polishing / etching.

Another supporting substrate may be used for removing the growth substrate. In order to improve the light efficiency of the LED chip on the opposite side of the growth substrate, the supporting substrate may be bonded using a reflective metal, As shown in FIG.

In addition, patterning of the growth substrate improves the light extraction efficiency by forming irregularities or slopes before or after the LED structure growth on the main surface (front surface or both sides) or side surfaces of the substrate. The size of the pattern can be selected from the range of 5 nm to 500 μm and it is possible to make a structure for improving the light extraction efficiency with a rule or an irregular pattern. Various shapes such as a shape, a column, a mountain, a hemisphere, and a polygon can be adopted.

In the case of the sapphire substrate, the crystals having hexagonal-rhombo-R3b symmetry have c-axis and a-side lattice constants of 13.001 and 4.758, respectively, and C (0001) (1102) plane, and the like. In this case, the C-plane is relatively easy to grow the nitride film, and is stable at high temperature, and thus is mainly used as a substrate for nitride growth.

Another material of the growth substrate is a Si substrate, which is more suitable for large-scale curing and relatively low in cost, so that mass productivity can be improved. There is a need for a technique for suppressing the occurrence of crystal defects due to the difference in lattice constant between the Si substrate having the (111) plane as the substrate surface and the lattice constant difference of about 17% with GaN. Further, the difference in thermal expansion coefficient between silicon and GaN is about 56%, and a technique for suppressing the wafer warping caused by the difference in thermal expansion rate is needed. Wafer warpage can cause cracking of the GaN thin film, and process control is difficult, which can cause problems such as a large scattering of the emission wavelength in the same wafer.

In addition, since the silicon (Si) substrate absorbs light generated from the GaN-based semiconductor and the external quantum efficiency of the light emitting device is lowered, the substrate may be removed as necessary, and Si, Ge, SiAl, A support substrate such as a metal substrate is further formed and used.

When a GaN thin film is grown on a different substrate such as the Si substrate, the dislocation density increases due to the lattice constant mismatch between the substrate material and the thin film material, and cracks and warpage Lt; / RTI > The buffer layer may be disposed between the growth substrate and the light emitting stack for the purpose of preventing dislocation and cracking of the light emitting stack. The buffer layer also functions to reduce the scattering of the wavelength of the wafer by adjusting the degree of warping of the substrate during the growth of the active layer.

Here, the buffer layer may be made of Al _x In _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, x + y? 1), in particular GaN, AlN, AlGaN, InGaN or InGaNAlN If necessary, materials such as ZrB2, HfB2, ZrN, HfN and TiN can be used. Further, a plurality of layers may be combined, or the composition may be gradually changed.

1 and 2 illustrate a flip-chip type light emitting device 20 having a signal transmission medium such as a bump, a pad, or a solder. However, a flip chip type light emitting device 20 having a signal transmission medium such as a wire, Type light emitting devices can be applied.

The reflective wall 30 is provided on the substrate 10 so as to surround the side surface 20a of the light emitting device 20 along the surface of the side surface 20a of the light emitting device 20 And may be in direct contact with the side surface 20a of the light emitting element 20. [

Here, the reflective wall 30 may be formed by selecting at least one of EMC including a reflective material, white silicon containing a reflective material, a photo solder resist (PSR), and combinations thereof.

Also, the reflective wall 30 may be dispensed or screen printed on the substrate 10 and the light emitting device 20.

Therefore, when the light emitting device 20 has a rectangular plate shape, the reflective wall 30 surrounds the vertical side 20a of the light emitting device 20 during the dispensing or screen printing process, A rectangular hole 30a may be formed in direct contact with the vertical side surface 20a.

Although not shown, when the light emitting device 20 is in the form of a circular plate, the reflective wall 30 surrounds the vertical outer surface of the light emitting device 20 during the dispensing or screen printing process, A circular hole can be formed which is in direct contact with the vertical outer diameter surface of the rotor 20.

In addition, the reflection wall 30 may have a very wide variety of holes, such as an elliptical hole, a polygonal hole, a trapezoidal shape, and a composite shape, depending on the shape of the light emitting device 20.

More specifically, for example, the reflective wall 30 may be formed of a modified silicone resin composition such as an epoxy resin composition, a silicone resin composition, a modified epoxy resin composition such as a silicone modified epoxy resin, an epoxy modified silicone resin, A resin such as a polyamide resin, a mid resin composition, a modified polyimide resin composition, polyphthalamide (PPA), polycarbonate resin, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), ABS resin, phenol resin, acrylic resin, Can be applied.

It is also possible to add a light reflective reflecting material such as titanium oxide, silicon dioxide, titanium dioxide, zirconium dioxide, potassium titanate, alumina, aluminum nitride, boron nitride, mullite, chromium, .

1 and 2, the light emitting device package 100 according to some embodiments of the present invention further includes a phosphor 40 installed in an optical path of the light emitting device 20 .

Here, the phosphor 40 may have the following composition formula and color, for example.

Oxide system: yellow and green Y3Al5O12: Ce, Tb3Al5O12: Ce, Lu3Al5O12: Ce

(Ba, Sr) 2SiO4: Eu, yellow and orange (Ba, Sr) 3SiO5: Ce

Eu, Sr2Si5N8: Eu, SrSiAl4N7: Eu, Eu3O3: Eu, Eu3O3: Eu,

The composition of the phosphor 40 should basically correspond to stoichiometry, and each element may be substituted with another element in each group on the periodic table. For example, Sr can be substituted with Ba, Ca, Mg, etc. of the alkaline earth (II) group, and Y can be replaced with lanthanum series of Tb, Lu, Sc, Gd and the like. Ce, Tb, Pr, Er, Yb and the like, and the active agent may be used alone or as a negative active agent for the characteristic modification.

As a substitute for the phosphor 40, materials such as a quantum dot may be used. Alternatively, a fluorescent material and QD may be mixed with the LED or used alone.

QD can be composed of a core (3 to 10 nm) such as CdSe and InP, a shell (0.5 to 2 nm) such as ZnS and ZnSe, a core, and a ligand for stabilizing the shell. You can implement color.

The coating method of the fluorescent material 40 or the quantum dot may be at least one of a method of being applied to an LED chip or a light emitting device, a method of covering a film form, a method of attaching a sheet form of a film or a ceramic fluorescent material, Can be used.

Dispensing and spray coating are common methods of dispensing, and dispensing includes mechanical methods such as pneumatic, screw and linear. It is also possible to control the amount of ink droplets by a small amount of jetting method and to control the color coordinates thereof by using a jetting method. The method of collectively applying the phosphor on the wafer level or the light emitting device substrate by the spray method can easily control productivity and thickness.

The method of directly covering the light emitting device or the LED chip in a film form can be applied by a method of electrophoresis, screen printing or phosphor molding, and the method may be different according to necessity of application of the side of the LED chip.

In order to control the efficiency of the long-wavelength light-emitting phosphor that reabsers light emitted from a short wavelength among two or more kinds of phosphors having different emission wavelengths, two or more kinds of phosphor layers having different emission wavelengths can be distinguished, and LED chips and two or more kinds of phosphors A DBR (ODR) layer may be included between each layer to minimize absorption and interference.

In order to form a uniform coating film, the phosphor may be formed into a film or ceramic shape, and then attached onto an LED chip or a light emitting device.

In order to make difference in light efficiency and light distribution characteristics, a photo-conversion material may be located in a remote format. In this case, the photo-conversion material is placed together with a light-transmitting polymer, glass or the like depending on its durability and heat resistance.

Such a phosphor coating technique plays a major role in determining optical characteristics in an LED device, and various control techniques such as thickness of a phosphor coating layer and uniform dispersion of a phosphor have been studied. The QD can also be placed in the LED chip or the light emitting element in the same manner as the phosphor, and can be positioned between the glass or translucent polymer material for light conversion.

Although not shown, in order to protect the LED chip or the light emitting device 20 from the external environment or improve the light extraction efficiency to the outside of the light emitting device 20, a light transmitting material may be used as the filler, And may be located on the element 20 or the phosphor 40.

Transparent organic solvents such as Epoxy, Silicone, Epoxy and Silicone Hybrid are applied and can be cured by heating, light irradiation and time lapse.

Silicone is classified into Polydimethyl siloxane as Methyl system and Polymethylphenyl siloxane as Phenyl system. It has different refractive index, moisture permeability, light transmittance, light stability and heat stability according to Methyl system and Phenyl system. In addition, the curing rate differs depending on the cross linker and the catalyst material, which affects the phosphor dispersion.

In order to minimize the gap between the refractive index of the outermost layer of the LED chip and the refractive index of the air emitted from the portion where the blue light is emitted, Can be sequentially stacked.

In general, the heat stability is most stable in the methyl system, and the rate of change is small in the order of the phenolic system, the hybrid system, and the epoxy system. Silicone can be classified into Gel type, Elastomer type and Resin type according to hardness.

The light emitting device 20 may further include the lens 50 of FIG. 4 to guide the light radiated from the light source. The lens 50 may be a secondary lens that is applied to the direct- have.

Although the light emitting device package 100 of FIG. 1 is provided in the form of a flip chip on a substrate, in another embodiment, it is assumed that the substrate 10 is omitted and the flip chip is directly mounted on the board of the application product .

3 is a light distribution diagram showing a light distribution curve according to a directivity angle of the light emitting device package 100 of FIG. 1, FIG. 4 is a cross-sectional view showing a state in which a lens 50 is installed in the light emitting device package 100 of FIG. 1 And FIG. 5 is a light distribution diagram showing a light distribution curve according to a directivity angle in a state where the lens 50 is installed in the light emitting device package 100 of FIG.

Accordingly, the light emitting device package 100 according to some embodiments of the present invention is configured such that the light generated from the light emitting device 20 of FIG. 1 is reflected by the reflective wall 30 without being exposed to outside air, The phosphor can be irradiated upward through the phosphor 40 in the range of about 45 degrees from the left and right in almost the state of improved linearity as shown in Fig.

That is, as shown in FIG. 4, in the direct-type light emitting device package widely used in the backlight unit, the light generated from the light emitting device package 100 according to some embodiments of the present invention is primarily It is possible to facilitate light control so as to be dispersed as wide as possible in the lateral direction as shown in Fig. 5 through the secondary lens 50 of Fig. 4, 20, the complicated phenomenon such as refraction of light, interference, or spectroscopic phenomenon does not occur in the secondary lens 50, and the color deviation or the lightness variation of the light irradiated to the light guide plate Can be greatly reduced.

6 to 9 are cross-sectional views illustrating a method of fabricating a light emitting device package 100 according to some embodiments of the present invention, and FIG. 10 is a cross-sectional view of a light emitting device package 100 according to some embodiments of the present invention. Fig.

6 to 10, in a method of manufacturing a light emitting device package 100 according to some embodiments of the present invention, first, as shown in FIG. 6, a substrate strip 10-1 is prepared (S2) of placing at least one light emitting device 20 on the substrate strip 10-1, as shown in Fig. 7, and then step S2 (S3) surrounding the side surface of the light emitting device 20 along the surface of the side surface 20a of the light emitting device 20 as shown in FIG. 9, (S4) of installing the fluorescent material 40 in the light path of the light emitting device 20 and then waving the substrate strip 10-1 along the cutting line CL of FIG. 9 (S5).

The step S3 of installing the reflective wall 30 may be performed by disposing the reflective wall 30 on the side surface 20a of the substrate strip 10-1 and the light emitting element 20 by using a dispenser or screen printing can do.

Therefore, according to the manufacturing method of the light emitting device package 100 according to some embodiments of the present invention, the reflective wall 30 can be easily manufactured by dispensing or screen printing without molding, The productivity can be greatly increased, the performance can be enhanced, and the unit cost can be greatly reduced.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: substrate
20: Light emitting element
20a: Side
30: reflective wall
30a: square hole
40: phosphor
50: lens
10-1: substrate strip
CL: Cutting line
100: Light emitting device package

Claims (11)

A light emitting element that emits light laterally;
A reflective wall surrounding the side of the light emitting device to surround the light emitting device to prevent light emission in the lateral direction of the light emitting device; And
And a substrate on which the light emitting device is mounted,
Wherein the reflective wall is disposed on the substrate,
The thickness of the light emitting element and the thickness of the reflecting wall, which are measured from the surface of the substrate,
And a phosphor layer of the same height is formed on the upper end of the light emitting element and the reflective wall. The method according to claim 1,
And the reflective wall is in direct contact with a side surface of the light emitting element. The method according to claim 1,
Wherein the reflective wall comprises at least one selected from EMC including at least a reflective material, white silicon containing a reflective material, a photo solder resist (PSR), and combinations thereof. The method according to claim 1,
Wherein the light emitting element has a rectangular plate shape,
Wherein the reflective wall surrounds the vertical side of the light emitting element and has a rectangular hole formed in direct contact with the vertical side of the light emitting element. delete The method according to claim 1,
Wherein the reflective wall is dispensed or screen printed on the substrate and the light emitting element. The method according to claim 1,
Wherein the substrate is made of at least one selected from a lead frame, a PCB, a FPCB, and a combination thereof. delete The method according to any one of claims 1 to 4 and 6 to 7,
Wherein the light emitting element is a flip chip. Preparing a substrate strip;
Placing at least one side emitting light emitting device on the substrate strip; And
Providing a reflective wall surrounding a side surface of the light emitting device along a side surface of the light emitting device;
, ≪ / RTI &
In the step of installing the reflecting wall,
The thickness of the light emitting element and the thickness of the reflective wall, which are measured from the surface of the substrate strip,
And a phosphor layer of the same height is formed on the upper end of the light emitting element and the reflective wall. 11. The method of claim 10,
Wherein the step of providing the reflective wall comprises dispensing or screen printing the reflective wall on the side of the substrate strip and the light emitting element.

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