WO2023101843A1

WO2023101843A1 - Light guide plate, lighting device including the same, and method of manufacturing the same

Info

Publication number: WO2023101843A1
Application number: PCT/US2022/050525
Authority: WO
Inventors: Donghyun Kim; Jooyoung Lee; Gun-Sang Yoon
Original assignee: Corning Incorporated
Priority date: 2021-11-30
Filing date: 2022-11-21
Publication date: 2023-06-08
Also published as: KR20230081059A

Abstract

A light guide plate includes: a transparent substrate; and a scattering layer including a matrix on the transparent substrate, a plurality of first and second scattering particles in the matrix, an edge surface extending between the upper surface and the lower surface, at least one of an average size and an average refractive index of the first and second scattering particles is different and each having a number density configured differently as compared to distance from the edge surface.

Description

LIGHT GUIDE PLATE, LIGHTING DEVICE INCLUDING THE SAME, AND METHOD OF MANUFACTURING THE SAME

BACKGROUND

1 . Cross-Reference to Related Applications

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of Korean Patent Application Serial No.10-2021-0168753 filed on November 30, 2021 , the content of which is relied upon and incorporated herein by reference in its entirety.

2. Field

[0002] One or more embodiments relate to a light guide plate, a lighting device including the light guide plate, and a method of manufacturing the light guide plate, and more particularly, to a lighting device in which light is input to an edge surface of a light guide plate, a light guide plate used for the lighting device, and a method of manufacturing the light guide plate.

3. Description of the Related Art

[0003] Light incident into a light guide plate through an edge surface may propagate, by total reflection, toward an opposite edge of the light guide plate. Also, the light collides with scattering particles in the light guide plate to be extracted from the light guide plate through an upper surface and/or a lower surface of the light guide plate. However, as a distance from the edge surface (light incident surface) of the light guide plate increases, luminance of the extracted light may decrease. Accordingly, uniformity of luminance of lighting may be reduced. To improve the uniformity of luminance of lighting, the thickness of a scattering layer may be increased as the distance from the edge surface (light incident surface) of the light guide plate increases. However, in this case, due to non-uniformity of the thickness of the light guide plate, color change may occur across the light guide plate.

SUMMARY

[0004] One or more embodiments include a lighting device having uniform luminance and a reduced color change, a light guide plate included in the lighting device, and a method of manufacturing the light guide plate. [0005] Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure.

[0006] According to one or more embodiments, a light guide plate includes a transparent substrate; and a scattering layer including a matrix on the transparent substrate, a plurality of first scattering particles in the matrix, and a plurality of second scattering particles in the matrix, wherein the scattering layer includes a lower surface in contact with the transparent substrate, an upper surface facing the lower surface, and an edge surface extending between the upper surface and the lower surface, at least one of an average size and an average refractive index of the plurality of first scattering particles is greater than at least one of an average size and an average refractive index of the plurality of second scattering particles, a number density of the plurality of first scattering particles in the scattering layer increases with increasing distance from the edge surface, and a number density of the plurality of second scattering particles in the scattering layer decreases with increasing distance from the edge surface.

[0007] In some embodiments, a sum of the number density of the plurality of first scattering particles and the number density of the plurality of second scattering particles in the scattering layer is substantially uniform regardless of the distance from the edge surface.

[0008] In some embodiments, the scattering layer comprises a plurality of first local regions including the plurality of first scattering particles and a plurality of second local regions including the plurality of second scattering particles, a number density of the plurality of first local regions in the scattering layer increases with increasing distance from the edge surface, and a number density of the plurality of second local regions in the scattering layer decreases with increasing distance from the edge surface.

[0009] In some embodiments, a thickness of the scattering layer in a direction perpendicular to the lower surface of the scattering layer is substantially uniform across the scattering layer.

[0010] In some embodiments, the plurality of first scattering particles are at least partially mixed with the plurality of second scattering particles.

[0011] In some embodiments, the scattering layer further comprises a plurality of third scattering particles in the matrix, at least one of an average size and an average refractive index of the plurality of third scattering particles is less than at least one of the average size and the average refractive index of the plurality of first scattering particles, and the plurality of third scattering particles are farther from the transparent substrate than the plurality of first scattering particles and the plurality of second scattering particles.

[0012] In some embodiments, at least one of the average size and the average refractive index of the plurality of third scattering particles is the same as at least one of the average size and the average refractive index of the plurality of second scattering particles.

[0013] In some embodiments, a number density of the plurality of third scattering particles in the scattering layer is substantially uniform regardless of the distance from the edge surface.

[0014] In some embodiments, the plurality of first scattering particles are closer to the transparent substrate than the plurality of second scattering particles.

[0015] In some embodiments, the scattering layer comprises a plurality of first local regions including the plurality of first scattering particles, a plurality of second local regions including parts of the matrix, a plurality of third local regions including the plurality of second scattering particles, and a plurality of fourth local regions including parts of the matrix, the plurality of first local regions and the plurality of second local regions are located on the substrate, and the plurality of third local regions and the plurality of fourth local regions are located on the plurality of first local regions and the plurality of second local regions, a number density of the plurality of first local regions in the scattering layer increases with increasing distance from the edge surface, a number density of the plurality of second local regions in the scattering layer decreases with increasing distance from the edge surface, a number density of the plurality of third local regions in the scattering layer decreases with increasing distance from the edge surface, and a number density the plurality of fourth local regions in the scattering layer increases with increasing distance from the edge surface.

[0016] According to one or more embodiments a lighting device comprise a light guide plate according to some embodiments and a light source for injecting light to the light guide plate through the edge surface of the scattering layer.

[0017] According to one or more embodiments, a method of manufacturing a light guide plate includes forming a scattering layer on a transparent substrate, the scattering layer including a lower surface in contact with the transparent substrate, an upper surface facing the lower surface, and an edge surface extending between the lower surface and the upper surface, wherein the forming of the scattering layer includes forming a plurality of first local region and a plurality of second local regions on the transparent substrate, each of the plurality of first local regions includes a part of a matrix and at least one first scattering particle, each of the plurality of second local regions includes a part of the matrix and at least one second scattering particle, at least one of an average size and an average refractive index of the at least one first scattering particle is greater than at least one of an average size and an average refractive index of the at least one second scattering particle, a number density of the plurality of first local regions in the scattering layer increases with increasing distance from the edge surface, and a number density of the plurality of second local regions in the scattering layer decreases with increasing distance from the edge surface.

[0018] In some embodiments, a sum of the number density of the plurality of first local regions and the number density of the plurality of second local regions in the scattering layer is substantially uniform regardless of the distance from the edge surface.

[0019] In some embodiments, a number density of the at least one first scattering particle in each of the plurality of first local regions is the same as a number density of the at least one second scattering particle in each of the plurality of second local regions.

[0020] In some embodiments, the forming of the scattering layer further comprises forming a plurality of third local regions in the plurality of first local regions and the plurality of second local regions, the third local region comprises a part of the matrix and at least one third scattering particle, and at least one of an average size and an average refractive index of the at least one third scattering particle is less than at least one of the average size and the average refractive index of the at least one first scattering particle.

[0021] In some embodiments, at least one of the average size and the average refractive index of the plurality of third scattering particles is the same as at least one of the average size and the average refractive index of the plurality of second scattering particles.

[0022] In some embodiments, a number density of the at least one third scattering particle in each of the plurality of third local regions is equal to each other.

[0023] In some embodiments, the forming of the plurality of third local regions starts before the forming of the plurality of first local regions and the plurality of second local regions is completed. [0024] According to one or more embodiments, a method of manufacturing a light guide plate includes forming a scattering layer on a substrate, the scattering layer including a lower surface in contact with the transparent substrate, an upper surface facing the lower surface, and an edge surface extending between the lower surface and the upper surface, wherein the forming of the scattering layer includes: forming, on the substrate, a plurality of first local regions and a plurality of second local regions; and forming a plurality of third local regions and a plurality of fourth local regions on the plurality of first local regions and the plurality of second local regions, each of the plurality of first local regions includes a part of a matrix and at least one first scattering particle, each of the plurality of second local regions includes a part of the matrix, each of the plurality of third local regions includes a part of the matrix and at least one second scattering particle, each of the plurality of fourth local regions includes a part of the matrix, at least one of an average size and an average refractive index of the at least one first scattering particle is greater than at least one of an average size and an refractive index of the at least one second scattering particle, a number density of the plurality of first local regions in the scattering layer increases with increasing distance from the edge surface, a number density of the plurality of second local regions in the scattering layer decreases with increasing distance from the edge surface, a number density of the plurality of third local regions in the scattering layer decreases with increasing distance from the edge surface, and a number density of the plurality of fourth local regions in the scattering layer increases with increasing distance from the edge surface.

[0025] In some embodiments, a sum of the number density of the plurality of first local regions and number density of the plurality of second local regions in the scattering layer is substantially uniform regardless of the distance from the edge surface, and a sum of the number density of the plurality of third local regions and the plurality of fourth local regions in the scattering layer is substantially uniform regardless of the distance from the edge surface.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: [0027] FIG. 1 illustrates a light guide plate according to one or more embodiments and a lighting device including the light guide plate;

[0028] FIG. 2 illustrates a light guide plate according to one or more embodiments and a lighting device including the light guide plate;

[0029] FIG. 3 illustrates a light guide plate according to one or more embodiments and a lighting device including the light guide plate;

[0030] FIG. 4 is a flowchart of a method of manufacturing a light guide plate according to one or more embodiments;

[0031] FIG. 5 is a flowchart of a method of manufacturing a light guide plate according to one or more embodiments; and

[0032] FIG. 6 is a flowchart of a method of manufacturing a light guide plate according to one or more embodiments.

DETAILED DESCRIPTION

[0033] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description.

[0034] FIG. 1 illustrates a light guide plate 100 according to one or more embodiments and a lighting device 1000 including the light guide plate 100.

[0035] Referring to FIG. 1 , the lighting device 1000 may include the light guide plate 100, a first light source 201 , and a second light source 202. In some embodiments, the lighting device 1000 may not include the second light source 202.

[0036] The light guide plate 100 may be transparent when the first light source 201 and the second light source 202 are turned off. The light guide plate 100 may include a transparent substrate 110 and a scattering layer 120 on the transparent substrate 110. The transparent substrate 110 may include an inorganic material or an organic material. The transparent substrate 110 may include, for example, glass or polymethyl methacrylate (PMMA). When the transparent substrate 110 includes glass, aesthetics may be improved, and color shift over time may be reduced so that lifespan may be improved and mechanical strength may be improved. [0037] The scattering layer 120 may include a lower surface 120L in contact with the transparent substrate 110, an upper surface 12011 opposite the lower surface 120L, a first edge surface 120E1 extending between the lower surface 120L and the upper surface 12011, and a second edge surface 120E2 opposite the first edge surface 120E1 . The thickness T of the scattering layer 120 may be defined between the lower surface 120L and the upper surface 12011 of the scattering layer 120. The thickness T of the scattering layer 120 may extend in a direction perpendicular to the lower surface 120L and the upper surface 12011 of the scattering layer 120. The thickness T of the scattering layer 120 may be substantially uniform across the scattering layer 120. For example, the thickness T of the scattering layer 120 may fluctuate within about 5% of the thickness T of the scattering layer 120. Accordingly, a color change due to the fluctuation of the thickness T of the scattering layer 120 may be reduced. In some embodiments, the thickness T of the scattering layer 120 may be about 1 pm to about 10 pm. The upper surface 12011 and the lower surface 120L of the scattering layer 120 may be flat.

[0038] The scattering layer 120 may include a matrix MT on the transparent substrate 110, and a plurality of first scattering particles P1 and the second scattering particles P2 in the matrix MT. The matrix MT may cover the first scattering particles P1 and the second scattering particles P2. The matrix MT may include, for example, acryl resin, melamine resin, nylon, polystyrene, polycarbonate, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyethylene, polymethyl methacrylate, tetrafluoroethylene, polyethylene trifluoro chloride, or polytetrafluoroethylene. In some embodiments, the matrix MT may include an organic-inorganic composite material. The matrix MT may be transparent. The matrix MT may have a refractive index of about 1.3 to about 1 .7. [0039] The first scattering particles P1 and the second scattering particles P2 may include, for example, TiC>2, ZrC>2, BaTiOs, SnC>2, ln2Os, HfO, Nb20s, Ta2Os, CaCOs, or BaSC . In some embodiments, the first scattering particles P1 and the second scattering particles P2 may include organic materials. In some embodiments, the first scattering particles and the second scattering particles P2 may include voids. In some embodiments, the first scattering particles P1 may include a material different from a material of the second scattering particles P2. However, in some embodiments, the first scattering particles P1 may include the same material as the material of the second scattering particles P2. [0040] In some embodiments, the average refractive index of the first scattering particles P1 may be greater than the average refractive index of the second scattering particles P2. The average refractive index of the first scattering particles P1 may be defined as a value obtained by dividing the sum of the refractive indexes of the first scattering particles P1 by the number of the first scattering particles P1. Likewise, the average refractive index of the second scattering particles P2 may be defined as a value obtained by dividing the sum of the refractive indexes of the second scattering particles P2 by the number of the second scattering particles P2. For example, the average refractive index of the first scattering particles P1 may be 2 to 3, and the average refractive index of the second scattering particles P2 may be 1.7 to 2.5.

[0041] In some embodiments, the average size of the first scattering particles P1 may be greater than the average size of the second scattering particles P2. The average size of the first scattering particles P1 may be defined as a value obtained by dividing the sum of the diameters of the first scattering particles P1 by the number of the first scattering particles P1. Likewise, the average size of the second scattering particles P2 may be defined as a value obtained by dividing the sum of the diameters of the second scattering particles P2 by the number of the second scattering particles P2. For example, the average size of the first scattering particles P1 may be about 100 nm to about 500 nm, and the average size of the second scattering particles P2 may be about 30 nm to about 200 nm.

[0042] At least one of the average refractive index and the average size of the first scattering particles P1 may be greater than at least one of the average refractive index and the average size of the second scattering particles P2. Accordingly, the first scattering particles P1 may exhibit excellent light scattering performance than the second scattering particles P2.

[0043] When the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120 and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120, the number density of the first scattering particles P1 in the scattering layer 120 may increase with increasing distance from the first edge surface 120E1. Furthermore, the number density of the first scattering particles P1 in the scattering layer 120 may increase with increasing distance from the second edge surface 120E2. Accordingly, the number density of the first scattering particles P1 in the scattering layer 120 may be minimal in the vicinity of the first edge surface 120E1 and the second edge surface 120E2, and may be maximal at the center of the scattering layer 120 between the first edge surface 120E1 and the second edge surface 120E2.

[0044] However, when the second light source 202 is not present, the number density of the first scattering particles P1 in the scattering layer 120 increases with increasing distance from the first edge surface 120E1, and the number density of the first scattering particles P1 in the scattering layer 120 is minimal in the vicinity of the first edge surface 120E1 , and maximal in the vicinity of the second edge surface 120E2. [0045] In the specification, the number density of the first scattering particles P1 in the scattering layer 120 is a value obtain by dividing the number of the first scattering particles P1 in each region of the scattering layer 120 (for example, first to ninth regions Ra to Ri), by the volume of each region of the scattering layer 120 (for example, the first to ninth regions Ra to Ri). In some embodiments, the number density of the first scattering particles P1 in the scattering layer 120 may be greater than about 0 pm- ³ and less than or equal to 200000 pm'³.

[0046] As illustrated in FIG. 1 , when the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120 and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120, the distance from the first edge surface 120E1 may increase from the first region Ra to the fifth region Re, and the number density of the first scattering particles P1 may increase from the first region Ra to the fifth region Re. Furthermore, the distance from the second edge surface 120E2 may increase from the ninth region Ri to the fifth region Re, and the number density of the first scattering particles P1 may increase from the ninth region Ri to the fifth region Re. Accordingly, the number density of the first scattering particles P1 in the fifth region Re may be maximal, and the number densities of the first scattering particles P1 in the first region Ra and the ninth region Ri may be minimal.

[0047] However, when the lighting device 1000 does not include the second light source 202, the distance from the first edge surface 120E1 may increase from the first region Ra to the ninth region Ri, and the number density of the first scattering particles P1 may increase from the first region Ra to the ninth region Ri. Accordingly, the number density of the first scattering particles P1 in the ninth region Ri may be maximal, and the number density of the first scattering particles P1 in the first region Ra may be minimal. [0048] When the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120 and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120, the number density of the second scattering particles P2 in the scattering layer 120 may decrease with increasing distance from the first edge surface 120E1. Furthermore, the number density of the second scattering particles P2 in the scattering layer 120 may decrease with increasing distance from the second edge surface 120E2. Accordingly, the number density of the second scattering particles P2 in the scattering layer 120 may be maximal in the vicinity of the first edge surface 120E1 and the second edge surface 120E2, and may be minimal at the center of the scattering layer 120 between the first edge surface 120E1 and the second edge surface 120E2.

[0049] However, when the lighting device 1000 does not include the second light source 202, the number density of the second scattering particles P2 in the scattering layer 120 may decrease with increasing distance from the first edge surface 120E1 , and the number density of the second scattering particles P2 in the scattering layer 120 may be maximal in the vicinity of the first edge surface 120E1 , and minimal in the vicinity of the second edge surface 120E2.

[0050] In the specification, the number density of the second scattering particles P2 in the scattering layer 120 is a value obtained by dividing the number of the second scattering particles P2 in each region of the scattering layer 120 (for example, the first to ninth regions Ra to Ri) by the volume of each region of the scattering layer 120 (for example, the first to ninth regions Ra to Ri). In some embodiments, the number density of the second scattering particles P2 in the scattering layer 120 may be about 0 pm'³ to about 200000 pm'³.

[0051] As illustrated in FIG. 1 , when the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120 and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120, the distance from the first edge surface 120E1 may increase from the first region Ra to the fifth region Re, and the number density of the second scattering particles P2 may decrease from the first region Ra to the fifth region Re. Furthermore, the distance from the second edge surface 120E2 may increase from the ninth region Ri to the fifth region Re, and the number density of the second scattering particles P2 may decrease from the ninth region Ri to the fifth region Re. Accordingly, the number density of the second scattering particles P2 in the fifth region Re may be minimal, and the number densities of the second scattering particles P2 in the first region Ra and the ninth region Ri may be maximal.

[0052] However, when the lighting device 1000 does not include the second light source 202, the distance from the first edge surface 120E1 may increase from the first region Ra to the ninth region Ri, and the number density of the second scattering particles P2 may decrease from the first region Ra to the ninth region Ri. Accordingly, the number density of the second scattering particles P2 in the ninth region Ri may be minimal, and the number density of the second scattering particles P2 in the first region Ra may be maximal.

[0053] When the lighting device 1000 includes the first light source 201 and the second light source 202, as the number density of the first scattering particles P1 having relatively excellent scattering performance is lower in the first and second edge surfaces 120E1 and 120E2 having relatively high light intensity, the lighting device 1000 according to an embodiment of the disclosure may have uniform luminance. When the lighting device 1000 does not include the second light source 202, as the number density of the first scattering particles P1 having relatively excellent scattering performance is lower at the first edge surface 120E1 having relatively high light intensity, the lighting device 1000 according to an embodiment of the disclosure may have uniform luminance.

[0054] In some embodiments, the sum of the number density of the first scattering particles P1 and the number density of the second scattering particles P2 in the scattering layer 120 may be substantially uniform regardless of the distance from the first edge surface 120E1 or the second edge surface 120E2. For example, the sum of the number density of the first scattering particles P1 and the number density of the second scattering particles P2 in each of the first region Ra to the ninth region Ri in the scattering layer 120 may be uniform.

[0055] The scattering layer 120 may include a plurality of first local regions LR1 and a plurality of second local regions LR2. Each of the first local regions LR1 may include at least one of the first scattering particles P1 and part of the matrix MT. Each of the second local regions LR2 may include at least one of the second scattering particles P2 and part of the matrix MT. The first scattering particles P1 may be distributed in the first local regions LR1 , and the second scattering particles P2 may be distributed in the second local regions LR2. [0056] When the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120 and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120, the number density of the first local regions LR1 in the scattering layer 120 may increase with increasing distance from the first edge surface 120E1. Furthermore, the number density of the first local regions LR1 in the scattering layer 120 may increase with increasing distance from the second edge surface 120E2. Accordingly, the number density of the first local regions LR1 in the scattering layer 120 may be minimal in the vicinity of the first edge surface 120E1 and the second edge surface 120E2, and maximal at the center of the scattering layer 120 between the first edge surface 120E1 and the second edge surface 120E2.

[0057] However, when the lighting device 1000 does not include the second light source 202, the number density of the first local regions LR1 in the scattering layer 120 may increase with increasing distance from the first edge surface 120E1 , and the number density of the first local regions LR1 in the scattering layer 120 may be minimal in the vicinity of the first edge surface 120E1 , and maximal in the vicinity of the second edge surface 120E2.

[0058] In the specification, the number density of the first local regions LR1 in the scattering layer 120 is a value obtained by dividing the number of the first local regions LR1 in each region of the scattering layer 120 (for example, the first to ninth regions Ra to Ri) by the planar area of_each region of the scattering layer 120 (for example, the first to ninth regions Ra to Ri). In some embodiments, the number density of the first local regions LR1 in the scattering layer 120 may be greater than about 0 in'² and less than or equal to about 5760000 in'².

[0059] As illustrated in FIG. 1 , when the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120 and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120, the distance from the first edge surface 120E1 may increase from the first region Ra to the fifth region Re, and the number density of the first local regions LR1 from the first region Ra to the fifth region Re may increase. Furthermore, the distance from the second edge surface 120E2 may increase from the ninth region Ri to the fifth region Re, and the number density of the first local regions LR1 from the ninth region Ri to the fifth region Re may increase. Accordingly, the number density of the first local regions LR1 in the fifth region Re may be maximal, and the number densities of the first local regions LR1 in the first region Ra and the ninth region Ri may be minimal.

[0060] However, when the lighting device 1000 does not include the second light source 202, the distance from the first edge surface 120E1 may increase from the first region Ra to the ninth region Ri, and the number density of the first local regions LR1 from the first region Ra to the ninth region Ri may increase. Accordingly, the number density of the first local regions LR1 in the ninth region Ri may be maximal, and the number density of the first local regions LR1 in the first region Ra may be minimal.

[0061] When the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120 and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120, the number density of the second local regions LR2 in the scattering layer 120 may decrease with increasing distance from the first edge surface 120E1. Furthermore, the number density of the second local regions LR2 in the scattering layer 120 may decrease with increasing distance from the second edge surface 120E2. Accordingly, the number density of the second local regions LR2 in the scattering layer 120 may be maximal in the vicinity of the first edge surface 120E1 and the second edge surface 120E2, and may be minimal at the center of the scattering layer 120 between the first edge surface 120E1 and the second edge surface 120E2.

[0062] However, when the lighting device 1000 does not include the second light source 202, the number density of the second local regions LR2 in the scattering layer 120 may decrease with increasing distance from the first edge surface 120E1 , and the number density of the second local regions LR2 in the scattering layer 120 may be maximal in the vicinity of the first edge surface 120E1 , and minimal in the vicinity of the second edge surface 120E2.

[0063] In the specification, the number density of the second local regions LR2 in the scattering layer 120 is a value obtained by dividing the number of the second local regions LR2 in each region of the scattering layer 120 (for example, the first to ninth regions Ra to Ri) by the planar area of each region of the scattering layer 120 (for example, the first to ninth regions Ra to Ri). In some embodiments, the number density of the second local regions LR2 in the scattering layer 120 may be greater than about 0 im² and less than or equal to about 5760000 in'².

[0064] As illustrated in FIG. 1 , when the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120 and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120, the distance from the first edge surface 120E1 may increase from the first region Ra to the fifth region Re, and the number density of the second local regions LR2 from the first region Ra to the fifth region Re may decrease. Furthermore, the distance from the second edge surface 120E2 may increase from the ninth region Ri to the fifth region Re, and the number density of the second local regions LR2 from the ninth region Ri to the fifth region Re may decrease. Accordingly, the number density of the second local regions LR2 in the fifth region Re may be minimal, and the number densities of the second local regions LR2 in the first region Ra and the ninth region Ri may be maximal.

[0065] However, when the lighting device 1000 does not include the second light source 202, the distance from the first edge surface 120E1 may increase from the first region Ra to the ninth region Ri, and the number density of the second local regions LR2 from the first region Ra to the ninth region Ri may decrease. Accordingly, the number density of the second local regions LR2 in the ninth region Ri may be minimal, and the number density of the second local regions LR2 in the first region Ra may be maximal.

[0066] When the lighting device 1000 includes the first light source 201 and the second light source 202, as the number density of the first local regions LR1 having relatively excellent scattering performance is higher in the fifth region Re having relatively low light intensity, the lighting device 1000 according to an embodiment of the disclosure may have uniform luminance. Furthermore, when the lighting device 1000 includes the second light source 202, as the number density of the first local region LR1 having relatively excellent scattering performance is higher in the ninth region Ri having relatively low light intensity, the lighting device 1000 according to an embodiment of the disclosure may have uniform luminance.

[0067] In some embodiments, the sum of the number density of the first local regions LR1 in the scattering layer 120 and the number density of the second local regions LR2 may be substantially uniform regardless of the distance from the first edge surface 120E1 or the second edge surface 120E2. For example, the sum of the number density of the first local regions LR1 and the number density of the second local regions LR2 in each of the first region Ra to the ninth region Ri in the scattering layer 120 may be uniform. [0068] In some embodiments, the number density of at least one of the first scattering particles P1 in each of the first local regions LR1 may be the same as the number density of at least one of the second scattering particles P2 in each of the second local regions LR2. In the specification, the number density of at least one of the first scattering particles P1 in each of the first local regions LR1 is a value obtained by dividing the number of at least one of the first scattering particles P1 in each of the first local regions LR1 by the volume of each of the first local regions LR1. Furthermore, the number density of at least one of the second scattering particles P2 in each of the second local regions LR2 is a value obtained by dividing the number of at least one of the second scattering particles P2 in each of the second local regions LR2 by the volume of each of the second local regions LR2.

[0069] The first light source 201 may inject light into the scattering layer 120 through the first edge surface 120E1 of the scattering layer 120. The second light source 202 may inject light into the scattering layer 120 through the second edge surface 120E2 of the scattering layer 120. The light emitted by first light source 201 and the second light source 202 may include at least one of visible light, infrared, and ultraviolet. In some embodiments, the first light source 201 and the second light source 202 may each include a light-emitting diode (LED).

[0070] FIG. 2 illustrates a light guide plate 100a according to one or more embodiments and a lighting device 1000a including the light guide plate 100a. In the following description, differences between the light guide plate 100 of FIG. 1 and the light guide plate 100a of FIG. 2 are presented.

[0071] Referring to FIG. 2, a scattering layer 120a may further include a plurality of third scattering particles P3 in the matrix MT. The third scattering particles P3 may include, for example, TiO2, ZrO2, BaTiOs, SnO2, ln2Os, HfO, Nb20s, Ta2Os, CaCOs, or BaSO4. In some embodiments, the third scattering particles P3 may include the same material as the second scattering particles P2. However, in some embodiments, the third scattering particles P3 may include a material different from the second scattering particles P2.

[0072] At least one of the average refractive index and the average size of the third scattering particles P3 may be less than at least one of the average refractive index and the average size of the first scattering particles P1. In some embodiments, at least one of the average refractive index and the average size of the third scattering particles P3 may be substantially the same as at least one of the average refractive index and the average size of the second scattering particles P2.

[0073] In some embodiments, the average refractive index of the third scattering particles P3 may be less than the average refractive index of the first scattering particles P1. The average refractive index of the third scattering particles P3 may be defined as a value obtained by dividing the sum of the refractive indexes of the third scattering particles P3 by the number of the third scattering particles P3. For example, the average refractive index of the third scattering particles P3 may be 1.7 to 2.5. In some embodiments, the average refractive index of the third scattering particles P3 may be substantially same as the average refractive index of the second scattering particles P2. For example, the difference between the average refractive index of the third scattering particles P3 and the average refractive index of the second scattering particles P2 may be within about 5%.

[0074] In some embodiments, the average size of the third scattering particles P3 may be less than the average size of the first scattering particles P1. The average size of the third scattering particles P3 may be defined as a value obtained by dividing the sum of the diameters of the third scattering particles P3 by the number of the third scattering particles P3. For example, the average size of the third scattering particles P3 may be about 30 nm to about 200 nm. In some embodiments, the average size of the third scattering particles P3 may be substantially the same as the average size of the second scattering particles P2. For example, the difference between the average size of the third scattering particles P3 and the average size of the second scattering particles P2 may be about 5%.

[0075] In some embodiments, the third scattering particles P3 may be farther from the transparent substrate 110 than the first scattering particles P1 and the second scattering particles P2. The third scattering particles P3 may cover the first scattering particles P1 to prevent non-uniformity of the scattering layer 120a due to the first scattering particles P1 from being seen.

[0076] In some embodiments, the number density of the third scattering particles P3 in the scattering layer 120a may be substantially uniform regardless of the distance from the first edge surface 120E1. Furthermore, the number density of the third scattering particles P3 in the scattering layer 120a may be substantially uniform regardless of the distance from the second edge surface 120E2. [0077] In the specification, the number density of the third scattering particles P3 in the scattering layer 120a is a value obtained by dividing the number of the third scattering particles P3 in each region of the scattering layer 120a (for example, the first to ninth regions Ra to Ri) by the volume of each region of the scattering layer 120 (for example, the first to ninth regions Ra to Ri). In some embodiments, the number density of the third scattering particles P3 in the scattering layer 120a may be about 20 pm'³ to 200000 pm^-3. As illustrated in FIG. 2, the number density of the third scattering particles P3 in the first region Ra to the ninth region Ri may be uniform.

[0078] The scattering layer 120a may further include a plurality of third local regions LR3 on the first local regions LR1 and the second local regions LR2. Each of the third local regions LR3 may include at least one of the third scattering particles P3 and part of the matrix MT.

[0079] In some embodiments, the number density of at least one of the third scattering particles P3 in each of the third local regions LR3 may be identical to each other. In the specification, the number density of at least one of the third scattering particles P3 in each of the third local regions LR3 may be a value obtained by dividing the number of at least one of the third scattering particles P3 in each of the third local regions LR3 by the volume of each of the third local regions LR3. For example, the difference between the number densities of at least one of the third scattering particles P3 in the third local regions LR3 may be about 5%.

[0080] FIG. 3 illustrates a light guide plate 100b according to one or more embodiments and a lighting device 1000b including the light guide plate 100b. In the following description, the light guide plate 100 of FIG. 1 and the light guide plate 100b of FIG. 3 is presented.

[0081] Referring to FIG. 3, the first scattering particles P1 may be closer to the transparent substrate 110 than the second scattering particles P2. Accordingly, nonuniformity due to the first scattering particles P1 may not be seed.

[0082] A scattering layer 120b may include a plurality of first local regions LRa and a plurality of second local regions LRb on the transparent substrate 110 and a plurality of third local regions LRc and a plurality of fourth local regions LRd on the first local regions LRa and the second local regions LRb. In some embodiments, the fourth local regions LRd may be arranged on the first local regions LRa, and the third local regions LRc may be arranged on the second local regions LRb. Each of the first local regions LRa may include at least one of the first scattering particles P1 and part of the matrix MT. Each of the second local regions LRb may include part of the matrix MT. each of the third local regions LRc may include at least one of the second scattering particles P2 and part of the matrix MT. Each of the fourth local regions LRd may include part of the matrix MT. The first scattering particles P1 may be distributed in the first local regions LRa. The second scattering particles P2 may be distributed in the third local regions LRc.

[0083] When the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120b and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120b, the number density of the first local regions LRa in the scattering layer 120b may increase with increasing distance from the first edge surface 120E1. Furthermore, the number density of the first local regions LRa in the scattering layer 120b may increase with increasing distance from the second edge surface 120E2. Accordingly, the number density of the first local regions LRa in the scattering layer 120b may be minimal in the vicinity of the first edge surface 120E1 and the second edge surface 120E2, and maximal at the center of the scattering layer 120 between the first edge surface 120E1 and the second edge surface 120E2.

[0084] However, when the lighting device 1000b does not include the second light source 202, the number density of the first local regions LRa in the scattering layer 120b may increase with increasing distance from the first edge surface 120E1 , and the number density of the first local regions LR1 in the scattering layer 120b may be minimal in the vicinity of the first edge surface 120E1 , and maximal in the vicinity of the second edge surface 120E2.

[0085] In the specification, the number density of the first local regions LRa in the scattering layer 120b is a value obtained by dividing the number of the first local regions LRa in each region of the scattering layer 120b (for example, the first to ninth regions Ra to Ri) by the planar area of each region of the scattering layer 120b (for example, the first to ninth regions Ra to Ri). In some embodiments, the number density of the first local regions LRa in the scattering layer 120 may greater than about 0 in^-2 and less than or equal to about 5760000 in^-2.

[0086] As illustrated in FIG. 3, when the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120 and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120, the distance from the first edge surface 120E1 may increase from the first region Ra to the fifth region Re, and the number density of the first local regions LRa may increase from the first region Ra to the fifth region Re. Furthermore, the distance from the second edge surface 120E2 may increase from the ninth region Ri to the fifth region Re, and the number density of the first local regions LRa may increase from the ninth region Ri to the fifth region Re. Accordingly, the number density of the first local regions LRa in the fifth region Re may be maximal, and the number densities of the first local regions LRa in the first region Ra and the ninth region Ri may be minimal.

[0087] However, when the lighting device 1000b does not include the second light source 202, the distance from the first edge surface 120E1 may increase from the first region Ra to the ninth region Ri, and the number density of the first local regions LRa may increase from the first region Ra to the ninth region Ri. Accordingly, the number density of the first local regions LRa in the ninth region Ri may be maximal, and the number density of the first local regions LRa in the first region Ra may be minimal.

[0088] When the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120b and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120b, the number density of the second local regions LRb in the scattering layer 120b may decrease with increasing distance from the first edge surface 120E1. Furthermore, the number density of the second local regions LRb in the scattering layer 120b may decrease with increasing distance from the second edge surface 120E2. Accordingly, the number density of the second local regions LRb in the scattering layer 120b may be maximal in the vicinity of the first edge surface 120E1 and the second edge surface 120E2, and minimal at the center of the scattering layer 120b between the first edge surface 120E1 and the second edge surface 120E2.

[0089] However, when the lighting device 1000b does not include the second light source 202, the number density of the second local regions LRb in the scattering layer 120 may decrease with increasing distance from the first edge surface 120E1 , and the number density of the second local regions LRb in the scattering layer 120b may be maximal in the vicinity of the first edge surface 120E1 , and minimal in the vicinity of the second edge surface 120E2.

[0090] In the specification, the number density of the second local regions LRb in the scattering layer 120b is a value obtained by dividing the number of the second local regions LRb in each region of the scattering layer 120b (for example, the first to ninth regions Ra to Ri) by the planar area of each region of the scattering layer 120b (for example, the first to ninth regions Ra to Ri). In some embodiments, the number density of the second local regions LRb in the scattering layer 120b may be greater than about 0 in^-2 and less than or equal to about 5760000 in^-2.

[0091] As illustrated in FIG. 3, when the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120 and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120, the distance from the first edge surface 120E1 may increase from the first region Ra to the fifth region Re, and the number density of the second local regions LRb may decrease from the first region Ra to the fifth region Re. Furthermore, the distance from the second edge surface 120E2 may increase from the ninth region Ri to the fifth region Re, and the number density of the second local regions LRb may decrease from the ninth region Ri to the fifth region Re. Accordingly, the number density of the second local regions LRb in the fifth region Re may be minimal, and the number densities of the second local regions LRb in the first region Ra and the ninth region Ri may be maximal.

[0092] However, when the lighting device 1000b does not include the second light source 202, the distance from the first edge surface 120E1 may increase from the first region Ra to the ninth region Ri, and from the first region Ra to the ninth region Ri the number density of the second local regions LRb may decrease. Accordingly, the number density of the second local regions LRb in the ninth region Ri may be minimal, and the number density of the second local regions LR2 in the first region Ra may be maximal.

[0093] When the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120b and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120b, the number density of the third local regions LRc in the scattering layer 120b may decrease with increasing distance from the first edge surface 120E1. Furthermore, the number density of the third local regions LRc in the scattering layer 120b may decrease with increasing distance from the second edge surface 120E2. Accordingly, the number density of the third local regions LRc in the scattering layer 120b may be maximal in the vicinity of the first edge surface 120E1 and the second edge surface 120E2, and minimal at the center of the scattering layer 120b between the first edge surface 120E1 and the second edge surface 120E2. [0094] However, when the lighting device 1000b does not include the second light source 202, the number density of the third local regions LRc in the scattering layer 120b may decrease with increasing distance from the first edge surface 120E1 , and the number density of the third local regions LRc in the scattering layer 120b may be maximal in the vicinity of the first edge surface 120E1 , and minimal in the vicinity of the second edge surface 120E2.

[0095] In the specification, the number density of the third local regions LRc in the scattering layer 120b is a value obtained by dividing the number of the third local regions LRc in each region of the scattering layer 120b (for example, the first to ninth regions Ra to Ri) by the planar area of each region of the scattering layer 120b (for example, the first to ninth regions Ra to Ri). In some embodiments, the number density of the third local regions LRc in the scattering layer 120b may be greater than about 0 in^-2 and less than or equal to about 5760000 in^-2.

[0096] as illustrated in FIG. 3, when the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120 and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120, the distance from the first edge surface 120E1 may increase from the first region Ra to the fifth region Re, and from the first region Ra to the fifth region Re the number density of the third local regions LRc may decrease. Furthermore, the distance from the second edge surface 120E2 may increase from the ninth region Ri to the fifth region Re, and from the ninth region Ri to the fifth region Re the number density of the third local regions LRc may decrease. Accordingly, the number density of the third local regions LRc in the fifth region Re may be minimal, and the first region Ra and the number density of the third local regions LRc in the ninth region Ri may be maximal.

[0097] However, when the lighting device 1000b does not include the second light source 202, the distance from the first edge surface 120E1 may increase from the first region Ra to the ninth region Ri, and the number density of the third local regions LRc may decrease from the first region Ra to the ninth region Ri. Accordingly, the number density of the third local regions LRc in the ninth region Ri may be minimal, and the number density of the second local regions LR2 in the first region Ra may be maximal. [0098] When the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120b and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120b, the number density of the fourth local regions LRd in the scattering layer 120b may increase with increasing distance from the first edge surface 120E1. Furthermore, the number density of the fourth local regions LRd in the scattering layer 120b may increase with increasing distance from the second edge surface 120E2. Accordingly, the number density of the fourth local regions LRd in the scattering layer 120b may be minimal in the vicinity of the first edge surface 120E1 and the second edge surface 120E2, and maximal at the center of the scattering layer 120b between the first edge surface 120E1 and the second edge surface 120E2.

[0099] However, when the lighting device 1000b does not include the second light source 202, the number density of the fourth local regions LRd in the scattering layer 120b may increase with increasing distance from the first edge surface 120E1 , and the number density of the fourth local regions LRd in the scattering layer 120b may be minimal in the vicinity of the first edge surface 120E1 , and maximal in the vicinity of the second edge surface 120E2.

[00100] In the specification, the number density of the fourth local regions LRd in the scattering layer 120b is a value obtained by dividing the number of the fourth local regions LRd in each region of the scattering layer 120b (for example, the first to ninth regions Ra to Ri) by the planar area of each region of the scattering layer 120b (for example, the first to ninth regions Ra to Ri). In some embodiments, the number density of the fourth local regions LRd in the scattering layer 120b may be greater than about 0 in^-2 and less than or equal to about 5760000 in^-2. As illustrated in FIG. 3, when the first light source 201 injects light through the first edge surface 120E1 of the scattering layer 120b and the second light source 202 injects light through the second edge surface 120E2 of the scattering layer 120b, the distance from the first edge surface 120E1 may increase from the first region Ra to the fifth region Re, and the number density of the fourth local regions LRd may increase from the first region Ra to the fifth region Re. Furthermore, the distance from the second edge surface 120E2 may increase from the ninth region Ri to the fifth region Re, and the number density of the fourth local regions LRd may increase from the ninth region Ri to the fifth region Re. Accordingly, the number density of the fourth local regions LRd in the fifth region Re may be maximal, and the number densities of the fourth local regions LRd in the first region Ra and the ninth region Ri may be minimal.

[00101] However, when the lighting device 1000b does not include the second light source 202, the distance from the first edge surface 120E1 may increase from the first region Ra to the ninth region Ri, and the number density of the fourth local regions LRd may increase from the first region Ra to the ninth region Ri. Accordingly, the number density of the fourth local regions LRd in the ninth region Ri may be maximal, and the number density of the fourth local regions LRd in the first region Ra may be minimal.

[00102] In some embodiments, the sum of the number density of the first local regions LRa in the scattering layer 120b and the number density of the second local regions LRb may be substantially uniform regardless of the distance from the first edge surface 120E1 or the second edge surface 120E2. For example, the sum of the number density of the first local regions LRa and the number density of the second local regions LRb in each of the first region Ra to the ninth region Ri of the scattering layer 120b may be uniform.

[00103] Furthermore, the sum of the number density of the third local regions LRc and the number density of the fourth local regions LRd in the scattering layer 120b may be substantially uniform regardless of the distance from the first edge surface 120E1 or the second edge surface 120E2. For example, the sum of the number density of the third local regions LRc and the number density of the fourth local regions LRd in the first region Ra to the ninth region Ri of the scattering layer 120b may be uniform. [00104] FIG. 4 is a flowchart of a method 2000 of manufacturing a light guide plate according to one or more embodiments.

[00105] Referring to FIGS. 4 and 1 , the method 2000 of manufacturing a light guide plate may include forming the scattering layer 120 on the transparent substrate 110 (S2100). The forming of the scattering layer 120 (S2100) may include forming the first local regions LR1 and the second local regions LR2 on the transparent substrate 110 (S2110). For example, the first local regions LR1 and the second local regions LR2 may be formed by inkjet printing, Gravure printing, or spraying.

[00106] A first nozzle through which a first solution including a matrix material and the first scattering particles P1 and a second nozzle through which a second solution including the matrix material and the second scattering particles P2 are prepared. The first nozzle may sequentially drop a plurality of first drops including at least one of the first scattering particles P1 and the matrix material, one by one, onto the transparent substrate 110. Each of the first drops may become each of the first local regions LR1. The second nozzle may sequentially drop a plurality of second drops including at least one of the second scattering particles P2 and the matrix material, one by one, onto the transparent substrate 110. Each of the second drops may become each of the second local regions LR2.

[00107] FIG. 5 is a flowchart of a method of manufacturing a light guide plate 2000a according to one or more embodiments. In the following description, difference between the method 2000 of FIG. 4 and the method 2000a of FIG. 5 are presented.

[00108] Referring to FIGS. 2 and 5, the method 2000a of manufacturing a light guide plate may include forming the scattering layer 120a on the transparent substrate 110 (S2100a). The forming of the scattering layer 120a (S2100a) may include forming the first local regions LR1 and the second local regions LR2 on the transparent substrate 110 (S2110). Furthermore, the forming of the scattering layer 120a (S2100a) may further include the third local regions LR3 on the first local regions LR1 and the second local regions LR2 (S2120). For example, the first local regions LR1 , the second local regions LR2, and the third local regions LR3 may be formed by inkjet printing, Gravure printing, or spraying.

[00109] The first nozzle through which the first solution including the matrix material and the first scattering particles P1 is supplied, the second nozzle through which the second solution including the matrix material and the second scattering particles P2 is supplied, and a third nozzle through which a third solution including the matrix material and the third scattering particles P3 are prepared. The first nozzle may sequentially drop a plurality of first drops including at least one of the first scattering particles P1 and matrix material, one by one drop, onto the transparent substrate 110. Each of the first drops may become each of the first local regions LR1. The second nozzle may sequentially drop a plurality of second drops including at least one of the second scattering particles P2 and the matrix material, one by one, onto the transparent substrate 110. Each of the second drops may become each of the second local regions LR2. The third nozzle may sequentially drop a plurality of third drops including at least one of the third scattering particles P3 and the matrix material, one by one, onto the first drops and the second drops. Each of the third drops may become each of the third local regions LR3.

[00110] In an embodiment in which the third scattering particles P3 is substantially the same as the second scattering particles P2, while the first nozzle and the second nozzle are used, the third nozzle may not be used. In this case, the first nozzle may form the first local regions LR1, and the second nozzle may form the second local regions LR2 and the third local regions LR3. [00111] In some embodiments, the forming of the third local regions LR3 (S2120) may start before the forming of the first local regions LR1 and the second local regions LR2 is completed. For example, while the first nozzle forms the first local regions LR1 and the second nozzle forms the second local regions LR2, the third nozzle may form the third local regions LR3.

[00112] FIG. 6 is a flowchart of a method 2000b of manufacturing a light guide plate according to one or more embodiments.

[00113] Referring to FIGS. 6 and 3, the method 2000b of manufacturing a light guide plate may include forming the scattering layer 120b on the transparent substrate 110 (S2100b). The forming of the scattering layer 120b (S2100b) may include forming the first local regions LRa and the second local regions LRb on the transparent substrate 110 (S2110). Furthermore, the forming of the scattering layer 120b (S2100b) may further include forming the third local regions LRc and the fourth local regions LRd on the first local regions LRa and the second local regions LRb (S2120b). For example, the first local regions LRa, the second local regions LRb, the third local regions LRc, and the fourth local regions LRd may be formed by inkjet printing, Gravure printing, or spraying.

[00114] The first nozzle through which the first solution including the matrix material and the first scattering particles P1 is supplied, the second nozzle through which a second solution including the matrix material is supplied, and the third nozzle through which a third solution including the matrix material and the second scattering particles P2, and the fourth nozzle through which a fourth solution including the matrix material are prepared. The first nozzle may sequentially drop a plurality of first drops including at least one of the first scattering particles P1 and the matrix material, one by one, onto the transparent substrate 110. Each of the first drops may become each of the first local regions LRa. The second nozzle ma sequentially drop a plurality of second drops including the matrix material, one by one, onto the transparent substrate 110. Each of the second drops may become each of the second local regions LRb. The third nozzle may sequentially drop a plurality of third drops including at least one of the second scattering particles P2 and the matrix material, one by one, onto the first drops and the second drops. Each of the third drops may become each of the third local regions LRc. The fourth nozzle may sequentially drop a plurality of fourth drops including the matrix material, one by one, onto the first drops and the second drops. Each of the fourth drops may become each of the fourth local regions LRd. [00115] In some embodiments, while the first nozzle, the second nozzle, and the third nozzle are used, the fourth nozzle may not be used. In this case, the first nozzle may form the first local regions LRa, the second nozzle may form the second local regions LRb and the fourth local regions LRd, and the third nozzle may form the third local regions LRc.

[00116] In some embodiments, the forming of the third local regions LRc and the fourth local regions LRd (S2120b) may start before the forming of the first local regions LRa and the second local regions LRb is completed. For example, while the first nozzle forms the first local regions LRa and the second nozzle forms the second local regions LRb, the third nozzle may form the third local regions LRc and the fourth nozzle may form the fourth local regions LRd.

[00117] It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the following claims.

Claims

WHAT IS CLAIMED IS:

1 . A light guide plate comprising: a transparent substrate; and a scattering layer comprising a matrix on the transparent substrate, a plurality of first scattering particles in the matrix, and a plurality of second scattering particles in the matrix, wherein the scattering layer comprises a lower surface in contact with the transparent substrate, an upper surface facing the lower surface, and an edge surface extending between the upper surface and the lower surface, at least one of an average size and an average refractive index of the plurality of first scattering particles is greater than at least one of an average size and an average refractive index of the plurality of second scattering particles, a number density of the plurality of first scattering particles in the scattering layer increases with increasing distance from the edge surface, and a number density of the plurality of second scattering particles in the scattering layer decreases with increasing distance from the edge surface.

2. The light guide plate of claim 1 , wherein a sum of the number density of the plurality of first scattering particles and the number density of the plurality of second scattering particles in the scattering layer is substantially uniform regardless of the distance from the edge surface.

3. The light guide plate of claim 1 or claim 2, wherein the scattering layer comprises a plurality of first local regions including the plurality of first scattering particles and a plurality of second local regions including the plurality of second scattering particles, a number density of the plurality of first local regions in the scattering layer increases with increasing distance from the edge surface, and a number density of the plurality of second local regions in the scattering layer decreases with increasing distance from the edge surface.

4. The light guide plate of any of claim 1 to claim 3, wherein a thickness of the scattering layer in a direction perpendicular to the lower

27 surface of the scattering layer is substantially uniform across the scattering layer.

5. The light guide plate of any of claim 1 to claim 4, wherein the plurality of first scattering particles are at least partially mixed with the plurality of second scattering particles.

6. The light guide plate of any of claim 1 to claim 5, wherein the scattering layer further comprises a plurality of third scattering particles in the matrix, at least one of an average size and an average refractive index of the plurality of third scattering particles is less than at least one of the average size and the average refractive index of the plurality of first scattering particles, and the plurality of third scattering particles are farther from the transparent substrate than the plurality of first scattering particles and the plurality of second scattering particles.

7. The light guide plate of claim 6, wherein at least one of the average size and the average refractive index of the plurality of third scattering particles is the same as at least one of the average size and the average refractive index of the plurality of second scattering particles.

8. The light guide plate of claim 6 or claim 7, wherein a number density of the plurality of third scattering particles in the scattering layer is substantially uniform regardless of the distance from the edge surface.

9. The light guide plate of any of claims 1 to 8, wherein the plurality of first scattering particles are closer to the transparent substrate than the plurality of second scattering particles.

10. The light guide plate of claim 9, wherein the scattering layer comprises a plurality of first local regions including the plurality of first scattering particles, a plurality of second local regions including parts of the matrix, a plurality of third local regions including the plurality of second scattering particles, and a plurality of fourth local regions including parts of the matrix, the plurality of first local regions and the plurality of second local regions are located on the substrate, and the plurality of third local regions and the plurality of fourth local regions are located on the plurality of first local regions and the plurality of second local regions, a number density of the plurality of first local regions in the scattering layer increases with increasing distance from the edge surface, a number density of the plurality of second local regions in the scattering layer decreases with increasing distance from the edge surface, a number density of the plurality of third local regions in the scattering layer decreases with increasing distance from the edge surface, and a number density the plurality of fourth local regions in the scattering layer increases with increasing distance from the edge surface.

11. A lighting device comprising: a light guide plate according to any of claims 1 to claim 10; and a light source for injecting light to the light guide plate through the edge surface of the scattering layer.

12. A method of manufacturing a light guide plate, the method comprising: forming a scattering layer on a transparent substrate, the scattering layer comprising a lower surface in contact with the transparent substrate, an upper surface facing the lower surface, and an edge surface extending between the lower surface and the upper surface, wherein the forming of the scattering layer comprises forming a plurality of first local region and a plurality of second local regions on the transparent substrate, each of the plurality of first local regions comprises a part of a matrix and at least one first scattering particle, each of the plurality of second local regions comprises a part of the matrix and at least one second scattering particle, at least one of an average size and an average refractive index of the at least one first scattering particle is greater than at least one of an average size and an average refractive index of the at least one second scattering particle, a number density of the plurality of first local regions in the scattering layer increases with increasing distance from the edge surface, and a number density of the plurality of second local regions in the scattering layer decreases with increasing distance from the edge surface.

13. The method of claim 12, wherein a sum of the number density of the plurality of first local regions and the number density of the plurality of second local regions in the scattering layer is substantially uniform regardless of the distance from the edge surface.

14. The method of claim 12 or claim 13, wherein a number density of the at least one first scattering particle in each of the plurality of first local regions is the same as a number density of the at least one second scattering particle in each of the plurality of second local regions.

15. The method of any of claims 12 to 14, wherein the forming of the scattering layer further comprises forming a plurality of third local regions in the plurality of first local regions and the plurality of second local regions, the third local region comprises a part of the matrix and at least one third scattering particle, and at least one of an average size and an average refractive index of the at least one third scattering particle is less than at least one of the average size and the average refractive index of the at least one first scattering particle.

16. The method of claim 15, wherein at least one of the average size and the average refractive index of the plurality of third scattering particles is the same as at least one of the average size and the average refractive index of the plurality of second scattering particles.

17. The method of claim 15 or claim 16, wherein a number density of the at least one third scattering particle in each of the plurality of third local regions is equal to each other.

18. The method of any of claims 15 to 17, wherein the forming of the plurality of third local regions starts before the forming of the plurality of first local regions and the plurality of second local regions is completed.

19. A method of manufacturing a light guide plate, the method comprising: forming a scattering layer on a substrate, the scattering layer comprising a lower surface in contact with the transparent substrate, an upper surface facing the lower surface, and an edge surface extending between the lower surface and the upper surface, wherein the forming of the scattering layer comprises: forming, on the substrate, a plurality of first local regions and a plurality of second local regions; and forming a plurality of third local regions and a plurality of fourth local regions on the plurality of first local regions and the plurality of second local regions, each of the plurality of first local regions comprises a part of a matrix and at least one first scattering particle, each of the plurality of second local regions comprises a part of the matrix, each of the plurality of third local regions comprises a part of the matrix and at least one second scattering particle, each of the plurality of fourth local regions comprises a part of the matrix, at least one of an average size and an average refractive index of the at least one first scattering particle is greater than at least one of an average size and an refractive index of the at least one second scattering particle, a number density of the plurality of first local regions in the scattering layer increases with increasing distance from the edge surface, a number density of the plurality of second local regions in the scattering layer decreases with increasing distance from the edge surface, a number density of the plurality of third local regions in the scattering layer decreases with increasing distance from the edge surface, and a number density of the plurality of fourth local regions in the scattering layer increases with increasing distance from the edge surface.

20. The method of claim 19, wherein a sum of the number density of the plurality of first local regions and number density of the plurality of second local regions in the scattering layer is substantially uniform regardless of the distance from the edge surface, and

31 a sum of the number density of the plurality of third local regions and the plurality of fourth local regions in the scattering layer is substantially uniform regardless of the distance from the edge surface.

32