KR102571786B1 - Light emitting device - Google Patents

Abstract

Embodiments include a substrate including a side connecting one side and the other side; and a light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer disposed on one surface of the substrate, and a plurality of light extraction lines spaced apart in a first direction on a side surface of the substrate, wherein the The first direction is a thickness direction of the substrate, and a shortest distance between a light extraction line closest to one surface of the substrate and one surface of the substrate among the plurality of light extraction lines may be greater than or equal to 70 μm and less than or equal to 120 μm.

Description

Light emitting device {LIGHT EMITTING DEVICE}

The embodiment relates to a light emitting device.

A light emitting device (Light Emitting Device) is a compound semiconductor device that converts electrical energy into light energy, and various colors can be implemented by adjusting the composition ratio of the compound semiconductor.

Nitride semiconductor light emitting devices have advantages of low power consumption, semi-permanent lifespan, fast response speed, safety, and environmental friendliness compared to existing light sources such as fluorescent lamps and incandescent lamps. Therefore, applications are expanding to backlights of LCD (Liquid Crystal Display) display devices, lighting devices, and automobile headlights.

The embodiment provides a light emitting device with excellent light extraction efficiency.

A light emitting device according to an embodiment of the present invention includes a substrate including a side surface connecting one surface and the other surface; and a light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer disposed on one surface of the substrate, and a plurality of light extraction lines spaced apart in a first direction on a side surface of the substrate, wherein the The first direction is the thickness direction of the substrate, and the shortest distance between a light extraction line closest to one surface of the substrate and one surface of the substrate among the plurality of light extraction lines is 90 μm or more and 120 μm or less.

Among the plurality of light extraction lines, a shortest distance between a light extraction line closest to the other surface of the substrate and the other surface of the substrate may be greater than or equal to 70 μm and less than or equal to 90 μm.

An interval between the plurality of light extraction lines may be greater than or equal to 35 μm and less than or equal to 50 μm.

A width of the plurality of light extraction lines in the first direction may be greater than or equal to 3 μm and less than or equal to 15 μm.

Among the plurality of light extraction lines, a light extraction line closest to one surface of the substrate may have the widest width.

A light emitting device according to an embodiment may include a reflective electrode layer disposed on the second semiconductor layer; a first insulating layer covering the light emitting structure on which the reflective electrode layer is disposed; a first electrode pad connected to the first semiconductor layer through the first insulating layer; and a second electrode pad connected to the second semiconductor layer through the first insulating layer.

The plurality of light extraction lines may have a rougher surface than the rest of the area.

According to the embodiment, light extraction efficiency is improved on the side of the substrate.

Various advantageous advantages and effects of the present invention are not limited to the above description, and will be more easily understood in the process of describing specific embodiments of the present invention.

1 is a view showing a light emitting device according to an embodiment of the present invention,
2 is a view for explaining a light extraction line formed on a side surface of a substrate;
3A to 3C are photographs showing light extraction lines having discontinuous sections due to laser interference;
4 is a photograph showing a light extraction line formed on a side surface of a substrate;
5 is a photograph in which light is emitted from a light extraction line formed on a side surface of a substrate;
6 is a view showing a light emitting device package according to an embodiment of the present invention;
7A to 7D are views for explaining a method of manufacturing a light emitting device package according to an embodiment of the present invention.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated and described in the drawings. However, this is not intended to limit the embodiments of the present invention to specific embodiments, and should be understood to include all changes, equivalents, or substitutes included in the spirit and technical scope of the embodiments.

Terms including ordinal numbers, such as first and second, may be used to describe various components, but the components are not limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a second element may be named a first element without departing from the scope of rights of an embodiment, and similarly, the first element may also be named a second element. The terms and/or include any combination of a plurality of related recited items or any of a plurality of related recited items.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the embodiments of the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

In the description of the embodiment, in the case where an element is described as being formed “on or under” of another element, on or under (on or under) or under) includes both elements formed by directly contacting each other or by indirectly placing one or more other elements between the two elements. In addition, when expressed as "on or under", it may include the meaning of not only the upward direction but also the downward direction based on one element.

Hereinafter, the embodiment will be described in detail with reference to the accompanying drawings, but the same or corresponding components regardless of reference numerals are given the same reference numerals, and overlapping descriptions thereof will be omitted.

1 is a view showing a light emitting device according to an embodiment of the present invention, FIG. 2 is a view for explaining a light extraction line formed on a side surface of a substrate, and FIGS. 3A to 3C have a discontinuous section by laser interference. This is a picture showing the light extraction line.

Referring to FIG. 1 , a light emitting device 100 according to an embodiment includes a substrate 110, a light emitting structure 120, a first insulating layer 142, a first electrode pad 150, and a second electrode pad 160. ).

The substrate 110 includes a conductive substrate or an insulating substrate. The substrate 110 may be a material suitable for growing semiconductor materials or a carrier wafer. The substrate 110 may be formed of a material selected from sapphire (Al ₂ O ₃ ), GaN, SiC, GaAs, GaN, ZnO, Si, GaP, InP, and Ge, but is not limited thereto.

The light emitting structure 120 is disposed on one surface 111 of the substrate 110 and includes a first semiconductor layer 121 , an active layer 122 , and a second semiconductor layer 123 . The light emitting structure 120 may be separated into a plurality of pieces in the process of cutting the substrate 110 .

Referring to FIG. 2 , the substrate 110 includes one surface 111 , the other surface 112 , and a side surface 113 connecting the one surface 111 and the other surface 112 . A plurality of light extraction lines DL may be formed on the side surface 113 in the thickness direction.

The light extraction line DL may have an amorphous structure by being partially melted by a laser and then cooled. The light extraction line DL is relatively fragile and may be cut in the thickness direction by a weak impact.

The light extraction line DL has a rough surface compared to the rest of the surface of the side surface 113 . Therefore, in the embodiment, the light extraction efficiency may be improved by adjusting surface roughness by maximally adjusting the number of light extraction lines DL for cutting the substrate 110 .

In FIG. 2, it is described that there are three light extraction lines DL as an example, but the maximum number of light extraction lines DL can be formed within a range that satisfies a predetermined condition as will be described later to increase surface roughness. .

Among the plurality of light extraction lines DL, the shortest distance d1 between the light extraction line closest to the surface 111 of the substrate 110 (hereinafter referred to as the first light extraction line DL1) and the surface 111 of the substrate 110 ) may be 70 μm or more and 120 μm or less, or 90 μm or more and 110 μm or less.

If the distance between the first light extraction line DL1 and the light emitting structure 120 is less than 70 μm, the light emitting structure 120 may be disposed too close to the light emitting structure 120, and thus the chip may be damaged during cutting the substrate and may not emit light. In addition, when the distance between the first light extraction line DL1 and the light emitting structure 120 exceeds 120 μm, the distance at which the light extraction line DL can be formed is narrowed, resulting in interference.

Among the plurality of light extraction lines DL, the shortest distance d2 between the light extraction line closest to the other surface 112 of the substrate 110 (hereinafter referred to as the second light extraction line DL2) and the other surface 112 of the substrate 110 ) may be 70 μm or more and 90 μm or less, or 75 μm or more and 85 μm or less.

When the distance between the second light extraction line DL2 and the other surface 112 of the substrate 110 is less than 70 μm, the light extraction line may be discontinuously formed because the spot depth is too shallow. When the distance between the second light extraction line DL2 and the other surface 112 of the substrate 110 exceeds 90 μm, the distance between which the light extraction line DL can be formed is narrowed, resulting in interference. .

The distance L1 between the plurality of light extraction lines DL may be 35 μm or more and 50 μm or less, or 35 μm or more and 45 μm or less. When the interval is less than 35 μm, a section in which the light extraction line DL is not generated may occur due to interference during laser irradiation. When the interval exceeds 50 μm, the number of light extraction lines DL is reduced and light extraction efficiency is reduced.

3a to 3c are photographs of light extraction lines formed at various intervals on the side of a substrate having a thickness of 250 μm. As shown in FIG. 3A , when the distance between the second light extraction line DL2 and the other surface 112 of the substrate is 50 μm, it can be seen that a discontinuous section P occurs in a part of the second light extraction line DL2. . In addition, as shown in FIG. 3B, when the distance between the second light extraction line DL2 and the adjacent light extraction line DL3 is 20 μm, a discontinuous section (P) occurs in a part of the second light extraction line DL2 due to laser interference. ) can be seen.

Referring to FIG. 2 , the number N of light extraction lines DL may satisfy the following relational expression 1.

[Relationship 1]

Here, D _total is the thickness of the substrate 110, d1 is the shortest distance between the first light extraction line DL1 and one surface 111 of the substrate 110, and d2 is the second light extraction line DL2 and It is the shortest distance between the other surfaces 112 of the substrate 110, and L1 is the separation distance between the plurality of light extraction lines DL.

As described above, d1 may be 70 μm or more and 120 μm or less, d2 may be 70 μm or more and 90 μm or less, and L1 may be 35 μm or more and 50 μm or less.

That is, the number of the plurality of light extraction lines DL is obtained by subtracting the minimum distance d1 to be separated from the light emitting structure 120 and the minimum distance d2 to be separated from the surface of the substrate 110. It may be the maximum number that can be formed at uniform intervals L1 in the remaining thickness. Accordingly, it is possible to form the maximum number of light extraction lines DL while suppressing the occurrence of discontinuous sections.

When the thickness of the substrate 110 is 250 μm, d1 is 90 μm, d2 is 80 μm, and L1 is 40 μm, the number of light extraction lines DL may be three. In this case, since the number N of light extraction lines is an integer, decimal points may be rounded off.

Referring to FIG. 4 , the first light extraction line DL1 is disposed at a height of 90 μm from one surface 111 of the substrate 110, and the third light extraction line DL3 is disposed at a height of 130 μm from the one surface 111 of the substrate 110. The second light extraction line DL2 may be disposed at a height of 170 μm from one surface 111 of the substrate. In this case, it can be confirmed that there is no discontinuous section in all light extraction lines. Referring to FIG. 5 , it can be seen that the light extraction effect is excellent in the light extraction line DL.

Table 1 below shows the results of measuring the light output Po at the chip level while controlling the number and spacing of the light extraction lines differently, and Table 2 shows the results of evaluating the amount of light lm at the package level. In the first embodiment, two light extraction lines DL were formed at a height of 70 μm and a height of 170 μm on one surface 111 of the substrate 110, and in the second embodiment, one surface 111 of the substrate 110 3 light extraction lines DL were formed at 70 μm, 120 μm, and 170 μm, and in the third embodiment, three light extraction lines DL at 90 μm, 130 μm, and 170 μm were formed on one surface 111 of the substrate 110. A line DL was formed.

Example 1 Example 2 3rd embodiment size 1100 × 1100 1100 × 1100 1100 × 1100 prober Po 480.8 (100%) 483.5 (100.6%) 487.8 (101.5%) Integrating Sphere Po 512.06 (100%) 518.73 (101.3%) 514.24 (100.4%)

Example 1 Example 2 3rd embodiment luminous intensity (lm) 169.0 (100%) 170.0 (100.6%) 170.5 (100.9%) Cx 0.280 0.279 0.283 Cy 0.252 0.253 0.257

Looking at Tables 1 and 2, it can be seen that the luminous intensities of the second embodiment and the second embodiment are increased compared to the first embodiment. This is considered to be because the light extraction efficiency is improved as the number of light extraction lines increases.

Referring back to FIG. 1 , the first semiconductor layer 121 may be a compound semiconductor such as group III-V or group II-VI, and the first semiconductor layer 121 may be doped with a first dopant. The first semiconductor layer 121 is a semiconductor material having a composition formula of In _x1 Al _y1 Ga _{1 -x1- y1} N (0≤x1≤1, 0≤y1≤1, 0≤x1+y1≤1), for example It may be selected from GaN, AlGaN, InGaN, InAlGaN, and the like. Also, the first dopant may be an n-type dopant such as Si, Ge, Sn, Se, or Te. When the first dopant is an n-type dopant, the first semiconductor layer 121 doped with the first dopant may be an n-type semiconductor layer.

The active layer 122 is a layer where electrons (or holes) injected through the first semiconductor layer 121 and holes (or electrons) injected through the second semiconductor layer 123 meet. The active layer 122 transitions to a lower energy level as electrons and holes recombine, and may generate light having a wavelength corresponding to the transition. In this embodiment, the emission wavelength is not limited.

The active layer 122 may have a structure of any one of a single well structure, a multi-well structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum dot structure, or a quantum wire structure, and the active layer 122 The structure of is not limited to this.

The second semiconductor layer 123 may be implemented with a compound semiconductor such as group III-V or group II-VI, and the second semiconductor layer 123 may be doped with a second dopant. The second semiconductor layer 123 is a semiconductor material having a composition formula of In _x5 Al _y2 Ga _1-x5-y2 N (0≤x5≤1, 0≤y2≤1, 0≤x5+y2≤1) or AlInN, AlGaAs , GaP, GaAs, GaAsP, may be formed of a material selected from AlGaInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, or Ba, the second semiconductor layer 123 doped with the second dopant may be a p-type semiconductor layer.

Although not shown, an electron blocking layer (EBL) may be disposed between the active layer 122 and the second semiconductor layer 123 . The electron blocking layer blocks the flow of electrons supplied from the first semiconductor layer 121 to the second semiconductor layer 123, thereby increasing the probability of recombination of electrons and holes in the active layer 122.

In the light emitting structure 120 , a first groove H1 through which the first semiconductor layer 121 is exposed may be formed through the second semiconductor layer 123 and the active layer 122 . The first semiconductor layer 121 may also be partially etched by the first groove H1. The number of first grooves H1 may be plural. A first ohmic electrode 151 may be disposed in the first groove H1 to be electrically connected to the first semiconductor layer 121 . A second ohmic electrode 131 may be disposed under the second semiconductor layer 123 .

The first ohmic electrode 151 and the second ohmic electrode 131 are indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), and indium gallium oxide (IGZO). zinc oxide), indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), SnO, InO, INZnO, ZnO, IrOx, RuOx, NiO, Ti, Al , Ni, Cr, and optional compounds or alloys thereof, and may be formed of at least one layer. The thickness of the ohmic electrode is not particularly limited.

The protective layer 141 may insulate the first ohmic electrode 151 from the active layer 122 and the second semiconductor layer 123 . The protective layer 141 may be entirely formed on the light emitting structure 120 except for a region where the first ohmic electrode 151 and the second ohmic electrode 131 are formed.

The protective layer 141 may include an insulating material or an insulating resin formed of at least one of oxide, nitride, fluoride, and sulfide having at least one of Al, Cr, Si, Ti, Zn, and Zr. The protective layer 141 may be selectively formed from, for example, SiO2, Si3N4, Al2O3, and TiO2. The protective layer 141 may be formed as a single layer or multiple layers, but is not limited thereto.

The reflective electrode layer 132 may be disposed on the second ohmic electrode 131 . The reflective electrode layer 132 may be formed of a metallic or non-metallic material. The metallic reflective electrode layer 132 is In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, W, Ti, Ag, Cr, Mo, Nb, Al , Ni, Cu, and may include any one of metals selected from WTi.

The first insulating layer 142 entirely covers the light emitting structure 120 on which the reflective electrode layer 132 is disposed. The first insulating layer 142 may include an insulating material or an insulating resin formed of at least one of oxide, nitride, fluoride, and sulfide having at least one of Al, Cr, Si, Ti, Zn, and Zr. The first insulating layer 142 may be selectively formed from, for example, SiO2, Si3N4, Al2O3, and TiO2. The first insulating layer 142 may be formed as a single layer or multiple layers, but is not limited thereto.

The first insulating layer 142 may be a reflective layer. Specifically, the first insulating layer 142 includes a structure in which two or more pairs of first layers having a first refractive index and second layers having a second refractive index are alternately stacked, and the first layer and the second layer have a refractive index It can be formed of a conductive or insulating material that is between 1.5 and 2.4. Such a structure may be a distributed bragg reflection (DBR) structure. In addition, a dielectric layer having a low refractive index and a metal layer may be stacked (omnidirectional reflector).

With this configuration, most of the light emitted from the active layer 122 toward the second semiconductor layer 123 may be reflected toward the substrate 110 . Accordingly, reflection efficiency can be increased and light extraction efficiency can be improved.

The first electrode pad 150 may be electrically connected to the first ohmic electrode 151 through the first insulating layer 142 . The area of the first ohmic electrode 151 increases as it approaches the substrate 110, while the area of the first electrode pad 150 decreases as it approaches the substrate 110.

The second electrode pad 160 may pass through the first insulating layer 142 and be electrically connected to the second ohmic electrode 131 and the reflective electrode layer 132 .

The first electrode pad 150 and the second electrode pad 160 are In, Co, Si, Ge, Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, W, Ti, It may include any one of metals selected from Ag, Cr, Mo, Nb, Al, Ni, Cu, and WTi.

6 is a view showing a light emitting device package according to an embodiment of the present invention.

Referring to FIG. 6 , a wavelength conversion layer 180 may be disposed on the substrate 110 . Light in a blue wavelength band emitted from the active layer 122 by the wavelength conversion layer 180 may be converted into white light. A package having this structure may be a chip scale package (CSP).

In the wavelength conversion layer 180, phosphors or quantum dots may be dispersed in a polymer resin. The type of phosphor is not particularly limited. At least one of YAG-based, TAG-based, silicate-based, sulfide-based, and nitride-based fluorescent materials may be included to implement white light.

Referring to FIG. 7A , a first semiconductor layer 121 , an active layer 122 , and a second semiconductor layer 123 are sequentially formed on a substrate 110 . Thereafter, at least one first groove H1 exposing the first semiconductor layer 121 may be formed by etching the second semiconductor layer 123 and the active layer 122 .

Referring to FIG. 7B , after the protective layer 141 is formed on the light emitting structure 120 in which the first groove H1 is formed, a portion of the protective layer 141 is removed to form the first ohmic electrode 151 and the second ohmic electrode 131. can do.

A reflective electrode layer 142 is formed on the second ohmic electrode 131 . The reflective electrode layer 142 may be formed in the order of Ag/Ni/Ti using sputtering. At this time, a plasma cleaning process may be performed to increase bonding strength between the second ohmic electrode 131 and the reflective electrode layer 142 .

After that, the first insulating layer 142 is formed entirely thereon. There is no limitation on the method of forming each layer. A mask pattern may be used or a photoresist may be used.

Referring to FIG. 7C , a portion of the first insulating layer 142 is etched, and a first electrode pad 150 and a second electrode pad 160 are respectively formed thereon.

Referring to FIG. 7D , scribing may be performed by forming a light extraction line in the thickness direction of the substrate. A laser having a relatively long wavelength may be used, and for example, a stealth laser having a wavelength of about 800 to 1200 nm may be used.

As the stealth laser, a YAG laser with a wavelength of 1064 nm may be used. In addition, the stealth laser has a frequency of 100 kHz, has an output of 0.45 W, and can use a laser spot (LS) having a diameter of 1 to 2 μm. In addition, a high repetition type laser oscillator may be used, and the moving speed of the laser light may be about 480 mm/s.

A plurality of laser spots LS are formed in the depth direction by focusing the stealth laser on the inside of the substrate 110 . Depths and intervals of the plurality of laser spots LS may correspond to the aforementioned light extraction lines.

The laser spot LS is an area formed by heating and melting the substrate 110 by a laser, and is an area in which the crystal structure is transformed into an amorphous structure in the process of cooling the molten portion. Since such an amorphous structure is easily damaged by impact, the laser spot LS may be used as a starting point for dividing the substrate 110 into the semiconductor light emitting device 100 as a unit device.

When the thickness of the substrate is 250 nm, the number of laser spots LS may be three. At this time, the laser spot LS2 closest to the other side 112 of the substrate is formed at a depth of 70 μm or more and 90 μm or less on the other side, and the laser spot LS1 closest to one side 111 of the substrate is one side of the substrate ( 111) can be formed at a height of 70 μm or more and 120 μm or less. In addition, the distance between the plurality of laser spots LS1, LS2, and LS3 can be controlled to be 35 μm or more and 50 μm or less.

Thereafter, an impact may be applied to the substrate 110 to cut the area irradiated with the laser to separate a plurality of light emitting devices. At this time, a plurality of light extraction lines are formed on the side surface of the cut substrate to increase roughness and increase light extraction efficiency.

The light emitting device of the embodiment may further include an optical member such as a light guide plate, a prism sheet, or a diffusion sheet to function as a backlight unit. In addition, the light emitting device of the embodiment may be further applied to a display device, a lighting device, and a pointing device.

In this case, the display device may include a bottom cover, a reflector, a light emitting module, a light guide plate, an optical sheet, a display panel, an image signal output circuit, and a color filter. The bottom cover, the reflector, the light emitting module, the light guide plate, and the optical sheet may form a backlight unit.

A reflector is disposed on the bottom cover, and the light emitting module emits light. The light guide plate is disposed in front of the reflector to guide light emitted from the light emitting module forward, and the optical sheet includes a prism sheet and is disposed in front of the light guide plate. A display panel is disposed in front of the optical sheet, an image signal output circuit supplies image signals to the display panel, and a color filter is disposed in front of the display panel.

In addition, the lighting device may include a light source module including a substrate and a light emitting device according to an embodiment, a heat dissipation unit dissipating heat from the light source module, and a power supply unit processing or converting an electrical signal received from the outside and providing the electrical signal to the light source module. . Furthermore, the lighting device may include a lamp, a head lamp, or a street lamp.

The embodiments of the present invention described above are not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible within a range that does not deviate from the technical spirit of the embodiments. It will be clear to those skilled in the art.

110: substrate
120: light emitting structure
121: first semiconductor layer
122: active layer
123: second semiconductor layer
DL1, DL2, DL3: light extraction lines

Claims (9)

A substrate including a side surface connecting one surface and the other surface; and
A light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer disposed on one surface of the substrate,
A side surface of the substrate includes a plurality of light extraction lines spaced apart in a first direction, the first direction being a thickness direction of the substrate;
A first shortest distance between a light extraction line closest to one surface of the substrate and one surface of the substrate among the plurality of light extraction lines is 70 μm or more and 120 μm or less,
The second shortest distance between the light extraction line closest to the other surface of the substrate and the other surface of the substrate among the plurality of light extraction lines is 70 μm or more and 90 μm or less,
The distance of the separation area between the plurality of light extraction lines is smaller than the first shortest distance and the second shortest distance,
The roughness of the plurality of light extraction lines is greater than the roughness of the separation region on the side surface of the substrate;
A width of the plurality of light extraction lines is smaller than that of the separation area.
delete According to claim 1,
An interval between the plurality of light extraction lines is greater than or equal to 35 μm and less than or equal to 50 μm.
According to claim 1,
A width of the plurality of light extraction lines in the first direction is greater than or equal to 3 μm and less than or equal to 15 μm.
According to claim 1,
A light emitting device having a width of a light extraction line closest to one surface of the substrate among the plurality of light extraction lines.
According to claim 1,
a reflective electrode layer disposed on the second semiconductor layer;
a first insulating layer covering the light emitting structure on which the reflective electrode layer is disposed;
a first electrode pad connected to the first semiconductor layer through the first insulating layer; and
A light emitting device comprising a second electrode pad connected to the second semiconductor layer through the first insulating layer.
According to claim 1,
The plurality of light extraction lines have a rougher surface than the rest of the light emitting device.
According to claim 1,
The number N of the light extraction lines satisfies the following relational expression 1.
[Relationship 1]

Here, D _total is the thickness of the substrate, d1 is the first shortest distance between the light extraction line closest to one surface of the substrate and one surface of the substrate, and d2 is the light extraction line closest to the other surface of the substrate and the light extraction line closest to the other surface of the substrate. The second shortest distance between the other surfaces of the substrate, and L1 is the separation distance between the plurality of light extraction lines.
According to claim 8,
The second shortest distance d2 is 70 μm or more and 90 μm or less, and the separation distance L1 between the plurality of light extraction lines is 35 μm or more and 50 μm or less.

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