JP6899540B2 - Manufacturing method of light guide plate, lighting device and light guide plate - Google Patents

Description

The present invention relates to a light guide plate, a lighting device, and a method for manufacturing the light guide plate.

Conventionally, a light guide plate is known in which light from a light source is incident on a side surface of the light guide plate and emitted from the surface of the light guide plate. In such a light guide plate, a plurality of recesses are formed on the back surface opposite to the front surface, and the recesses reflect the light incident from the side surface of the light guide plate toward the front surface. In recent years, a light guide plate in which a coating layer is coated on the front surface and the back surface in order to enhance the antifouling property of the light guide plate itself is also known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-49051

By the way, dirt accumulates in the recess on the back surface of the light guide plate. Even if the back surface of the light guide plate is wiped clean with a wiping wiper or the like, the wiping wiper may not reach the depth of the recess, and dirt in the recess may remain.

Further, depending on the method of forming the concave portion, the inner surface of the concave portion may have an angle partially different from the design intention, and when the portion is generated, the desired light distribution cannot be obtained.

An object of the present invention is to improve the wiping property in the recess of the light guide plate and to improve the accuracy of the light distribution control in the recess.

In order to solve the above problems, the light guide plate according to one aspect of the present invention is a light guide plate in which a plurality of recesses are formed on at least one of a pair of main surfaces facing each other, and a plurality of recesses are formed. The main surface is coated with an antifouling coating layer, and the bottom portion of the recess is thicker than the other portions.

Further, the lighting device according to one aspect of the present invention includes the light guide plate and a light source that causes light to enter an incident surface between a pair of main surfaces of the light guide plate.

Further, the method for manufacturing a light guide plate according to one aspect of the present invention includes a laser processing step of forming a plurality of recesses by laser processing on at least one of a pair of main surfaces of a base material serving as a light guide plate, and a plurality of recesses. A coating step of coating a coating layer having antifouling property on the formed main surface is included, and in the coating step, a coating layer is accumulated at the bottom of the recess so as to be thicker than other portions.

According to the present invention, it is possible to improve the wiping property in the recess of the light guide plate and to improve the accuracy of the light distribution control in the recess.

FIG. 1 is a perspective view of the lighting device according to the embodiment. FIG. 2 is a cross-sectional view of the lighting device according to the embodiment. FIG. 3 is an enlarged cross-sectional view showing a recess of the light guide plate according to the embodiment. FIG. 4 is an enlarged cross-sectional view showing a light guide plate in which an ideal recess is formed as a comparative example. FIG. 5 is a flowchart showing a flow of a method of manufacturing a light guide plate according to an embodiment. FIG. 6 is an enlarged cross-sectional view showing a part of the base material after the laser processing step. FIG. 7 is an enlarged cross-sectional view showing a part of the light guide plate according to the first modification.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement positions of the components, connection forms, etc. shown in the following embodiments are examples and are not intended to limit the present invention. Therefore, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept of the present invention will be described as arbitrary components.

It should be noted that each figure is a schematic view and is not necessarily exactly illustrated. Further, in each figure, the same reference numerals are given to substantially the same configurations, and duplicate description will be omitted or simplified.

Hereinafter, a light guide plate and a lighting device using the light guide plate according to the embodiment of the present invention will be described.

[Constitution]
First, the configuration of the lighting device according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view of the lighting device 10 according to the embodiment. FIG. 2 is a cross-sectional view of the lighting device 10 according to the embodiment.

As shown in FIGS. 1 and 2, the lighting device 10 is an edge light type lighting device and is fixed to the ceiling. Specifically, the lighting device 10 is fixed to the ceiling in a state of being connected to an external power source (not shown) arranged behind the ceiling.

The lighting device 10 includes a main body portion 11, a power supply portion 13, a pair of light emitting modules 15, and a pair of light guide plates 30.

The main body 11 is formed in a long box shape, and houses the power supply 13 electrically connected to an external power supply. Further, light guide plate support portions 21 are provided on both sides of the main body portion 11. Since the light guide plate support portion 21 is equivalent on both side portions of the main body portion 11, one light guide plate support portion 21 will be described, and the other light guide plate support portion 21 will be omitted.

The light guide plate support portion 21 is a rectangular groove portion recessed from one side surface of the main body portion 11 toward the other side. A plurality of screw holes 211 for screwing the light guide plate 30 are formed on the top surface of the light guide plate support portion 21. The plurality of screw holes 211 are arranged at predetermined intervals along the longitudinal direction of the main body 11. The light guide plate 30 supported by the light guide plate support portion 21 is arranged substantially parallel to the ceiling. Further, the inner surface of the light guide plate support portion 21 on the inner side is substantially orthogonal to the top surface of the light guide plate support portion 21. A light emitting module 15 is attached to the inner surface of the light guide plate support portion 21.

The light emitting module 15 is arranged in the light guide plate support portion 21, and includes a substrate 151 and a plurality of light sources 152.

The substrate 151 is a long rectangular plate-shaped substrate. The substrate 151 is installed on the inner side surface of the light guide plate support portion 21 so as to be parallel to the longitudinal direction of the main body portion 11.

The plurality of light sources 152 are so-called SMD (Surface Mount Devices) type LED elements. Specifically, the SMD type LED element is a package type LED element in which an LED chip (light emitting element) is mounted in a resin-molded cavity and a phosphor-containing resin is sealed in the cavity. The light source 152 is turned on and off by being controlled by a control unit (not shown) provided in the power supply unit 13. Further, each light source 152 is subjected to dimming and toning control by a control unit.

The light emitting module 15 is not limited to such a configuration, and a COB (Chip On Board) type light emitting module in which an LED chip is directly mounted on a substrate 151 may be used. Further, the light emitting element included in the light source 152 is not limited to the LED, and is, for example, a semiconductor light emitting element such as a semiconductor laser, or another solid light emitting element such as an EL element such as an organic EL (Electro Luminescence) or an inorganic EL. It may be.

The plurality of light sources 152 are arranged between the incident surface 31 of the light guide plate 30 and the inner surface of the light guide plate support portion 21. The light source 152 is arranged so that the exit direction in which the light is emitted faces the incident surface 31 of the light guide plate 30, and the light is incident toward the incident surface 31. That is, the emission direction of the light source 152 is substantially perpendicular to the incident surface 31 of the light guide plate 30.

The light guide plate 30 has a rectangular flat plate shape in a plan view. The shape of the light guide plate 30 is not limited to a rectangular shape, but may be a disk shape, a triangular shape, or another shape. The light guide plate 30 is an optical member that guides the light from the light source 152 toward the emission surface 32 described later. The light guide plate 30 is formed of a translucent resin such as polycarbonate or acrylic, but may be formed of other translucent material.

The light guide plate 30 is supported by the light guide plate support portion 21 so as to be substantially parallel to the ceiling. One side surface of the light guide plate 30 arranged in the light guide plate support portion 21 is an incident surface 31 on which light from a plurality of light sources 152 is incident. The incident surface 31 extends along the longitudinal direction of the main body 11. A plurality of light sources 152 are arranged at predetermined intervals along the extending direction of the incident surface 31.

Of the pair of main surfaces of the light guide plate 30, one main surface is a surface facing downward, and is an exit surface 32 that emits light. Of the pair of main surfaces of the light guide plate 30, the main surface on the opposite side is the back surface facing the ceiling, and is the reflection surface 33 that reflects the light passing through the light guide plate 30. In the light guide plate 30, an incident surface 31 is provided between the emitting surface 32 and the reflecting surface 33.

The entrance surface 31 and the exit surface 32 of the light guide plate 30 are flat. The reflection surface 33 of the light guide plate 30 is a surface opposite to the exit surface 32 of the light guide plate 30. A plurality of recesses 37 recessed toward the exit surface 32 are formed on the reflection surface 33 so as to be randomly dispersed in the reflection surface 33.

FIG. 3 is an enlarged cross-sectional view showing a recess 37 of the light guide plate 30 according to the embodiment. As shown in FIG. 3, the recess 37 is a prism recessed in a substantially frustum shape. The recess 37 is formed so that the upper bottom, which is the base end portion, has a larger area in a plan view than the lower bottom, which is the bottom portion. The recess 37 may be recessed in a truncated cone shape or in a truncated cone shape. The bottom of the recess 37 is formed in a concave curved surface.

Here, the light traveling through the light guide plate 30 is reflected by the inner surface of the recess 37 in the light guide plate 30. It is important to form the shape of the inner surface of the recess 37 into a shape suitable for the design intention in order to realize the desired light distribution.

FIG. 4 is an enlarged cross-sectional view showing a light guide plate 30A in which an ideal recess 37A is formed as a comparative example. As shown in FIG. 4, the recess 37A according to the comparative example is formed in a cone shape. In the case of the cone-shaped recess 37A as described above, the shape of the inner surface thereof is a uniform inclined surface in cross-sectional view from the base end portion to the tip end portion. That is, it is possible to realize an inclined surface having an angle corresponding to the design intention in the entire recess 37A. Such a recess 37A can be easily formed by mechanical cutting. However, in the case of manufacturing by laser processing, even if an attempt is made to form a cone-shaped recess, the tip of the recess is melted and then hardened, and as a result, the tip is as shown in FIG. Is a concave portion 37 having a concave curved surface shape. That is, at the time of designing, the cone-shaped recess 37B shown by the broken line in FIG. 3 is intended, but after manufacturing, it becomes a substantially frustum-shaped recess 37. If the shape of the tip of the concave portion 37 is a concave curved surface shape, the reflection of light at the portion will vary, and a desired light distribution cannot be obtained.

Therefore, in the light guide plate 30 according to the present embodiment, the coating layer 40 that coats the reflective surface 33 is responsible for light distribution control.

Specifically, as shown in FIG. 3, the reflective surface 33 of the light guide plate 30 is coated with a coating layer 40 having antifouling properties. Here, the antifouling property is a property that prevents the adhesion of dirt, and specifically, is a property that includes at least one of water and oil repellency and antistatic property. Water repellency and oil repellency are properties that prevent the adhesion of oil-based stains. The antistatic property is a property of preventing the adhesion of dust and the like by preventing the object from being charged. That is, the coating layer 40 may contain at least one of a material having water and oil repellency and a material having antistatic properties.

The material having water and oil repellency is, for example, an additive such as a resin having a water repellent group and a surfactant. The water-repellent group is a functional group having a particularly low surface free energy, and a fluoroalkyl group, a fluoroalkylene group, and an alkyl group as shown in Table 1 can be exemplified.

The structural formulas in Table 1 exemplify those having 1 carbon atom, CF ₃ − is a perfluoromethyl group, −CF ₂ − is a perfluoromethylene group, and CH ₃ − is a methyl group. Is.

It is also preferable to have a dimethylsiloxane group represented by the chemical formula (1) as the water-repellent group. The surface free energy can also be reduced when it has a dimethylsiloxane group. In the chemical formula (1), n is preferably an integer of 1 or more. The upper limit of n is not particularly limited, but is preferably 160 in practical use. When n is 160 or less, the physical characteristics of the film such as hardness are good.

Examples of the antistatic material include an electron conductive material, an ionic conductive material, and a hydrophilic material. Electroconducting materials include metals, conductive metal oxides, carbon and the like. Ionic conductive materials include surfactants, ionic liquids and the like. The hydrophilic material is a hydrophilic material having a hydrophilic group such as an OH group, a polyethylene oxide group, a polyether group, and a silanol group. Although not particularly limited, materials having visible light absorption such as metals, conductive metal oxides, and carbon that adversely affect the light guide property shall be avoided.

Further, the coating layer 40 contains a material having light diffusivity. The material having light diffusivity is particles having a refractive index different from that of the binder component in the coating layer 40, and examples thereof include resin-based or silica-based light-diffusing particles. Further, the light diffusing particles include inorganic type and organic type.

Examples of the inorganic light-diffusing particles include silicon oxide, barium sulfate, calcium carbonate, titanium oxide, mica, magnesium oxide, talc, aluminum hydroxide, and aluminum oxide. Examples of the organic light-diffusing particles include acrylic resin particles, urethane resin particles, benzoguanamine-based resin particles, polystyrene particles, silicone resin particles, melamine resin particles, and PTFE particles.

Further, examples of the light diffusing particles include hollow particles made of the above-mentioned materials, core-shell particles obtained by combining two or more kinds of particles, and inclusion particles. Although not particularly limited, it is preferable to appropriately select a binder component in the coating layer and a light diffusing particle having a refractive index difference of more than 0 and less than 0.2.

The coating layer 40 is coated with a substantially uniform thickness over the entire reflective surface 33. At the bottom of the recess 37, the coating layer 40 is thicker than the other portions. The recess 37 includes a first portion 401, which is a portion where the coating layer 40 is accumulated, and a second portion 402, which is a portion where the coating layer 40 is formed to have a uniform thickness. In the first part 401, the entire bottom of the recess 37 is covered, and the surface thereof is formed in a flat surface. Specifically, the surface of the first portion 401 is formed parallel to the surface outside the recess 37 in the light guide plate 30. The thickness T1 of the first portion 401 is, for example, 20 μm.

In this way, since the first portion 401 covers the entire bottom portion of the recess 37, the light that travels in the light guide plate 30 and reaches the bottom portion of the recess 37 is not reflected by the bottom portion and is not reflected by the bottom portion. Reflects on the surface of. As described above, since the surface of the first portion 401 is a plane parallel to the surface outside the recess 37 in the light guide plate 30, light is reflected in the same manner as the surface outside the recess 37. That is, the light can be reflected in the direction according to the design intention.

Here, the depth D1 from the surface of the coating layer 40 outside the recess 37 to the surface of the coating layer 40 at the bottom of the recess 37 is 3.5 times or less the opening diameter W1 in the recess 37. The opening diameter W1 is, for example, 100 μm or more and 250 μm or less. Based on the above-mentioned relationship, when the opening diameter W1 is 100 μm, the depth D1 may be 29 μm or less, and when the opening diameter W1 is 250 μm, the depth D1 may be 71 μm or less.

The opening diameter W1 is the diameter of the upper bottom portion when the recess 37 has a truncated cone shape. Further, the opening diameter W1 is the length of the portion having the largest width in the upper bottom portion when the recess 37 has a pyramidal trapezoidal shape.

In the second portion 402, a portion of the recess 37 above the bottom portion, that is, an inner peripheral surface which is an inclined surface reflecting the design intention is covered with a uniform thickness. As a result, the surface of the second portion 402 is parallel to the inclined surface of the recess 37. Further, the second portion 402 has a uniform thickness with respect to the thickness t2 of the coating layer 40 outside the recess 37. Here, the thickness t2 of the coating layer 40 outside the recess 37 is about 3 μm.

In this way, since the second portion 402 covers the inclined surface of the recess 37 with a uniform thickness, the light traveling through the light guide plate 30 and reaching the inclined surface is not reflected by the inclined surface of the recess 37. , Reflects on the surface of the second portion 402. As described above, since the surface of the second portion 402 is parallel to the inclined surface of the recess 37, it reflects light in the same manner as the inclined surface. That is, the light can be reflected in the direction according to the design intention.

Then, the light reflected by the reflecting surface 33 of the light guide plate 30 is emitted from the emitting surface 32 and becomes illumination light. When light passes through the coating layer 40, the light is diffused by the light diffusing particles contained in the coating layer 40. In particular, in the recess 37 of the light guide plate 30, there is a first portion 401 that is thicker than the other portions. In this first part, more light diffusing particles are present than in the other parts, so that the light is diffused more strongly.

[Production method]
Next, a method of manufacturing the light guide plate 30 according to the present embodiment will be described. FIG. 5 is a flowchart showing a flow of a manufacturing method of the light guide plate 30 according to the embodiment.

In the laser processing step S1, a plurality of recesses 37 are formed by laser processing on at least one of the pair of main surfaces of the base material 60 (see FIG. 6) to be the light guide plate 30. FIG. 6 is an enlarged cross-sectional view showing a part of the base material 60 after the laser processing step S1. As shown in FIG. 6, recesses 37 are randomly formed on one main surface 61 of the base material 60 over the entire surface.

Next, in the coating step S2, the coating layer 40 having antifouling property is coated on the main surface 61 of the base material 60. Specifically, an organic solvent containing at least one of a water-repellent and oil-repellent material and an antistatic material is coated on the main surface 61 of the base material 60 by coating or spraying. At this time, by appropriately adjusting the viscosity of the organic solvent, the coating amount, and the like, when the coating layer 40 is fixed to the main surface 61, the coating layer 40 is thicker than the other portions at the bottom of the recess 37. It will be accumulated. As a result, the light guide plate 30 shown in FIG. 3 is completed.

[Effects, etc.]
As described above, the light guide plate 30 according to the present embodiment is a light guide plate 30 in which a plurality of recesses 37 are formed on at least one of a pair of main surfaces facing each other, and the plurality of recesses 37 are formed. The main surface (reflective surface 33) is coated with an antifouling coating layer 40, and the bottom portion of the recess 37 is thicker than the other portions.

Further, the lighting device 10 according to the present embodiment includes the light guide plate 30 and a light source 152 for making light incident on an incident surface 31 between a pair of main surfaces of the light guide plate 30.

Further, with respect to the laser processing step S1 in which a plurality of recesses 37 are formed by laser machining on at least one of the pair of main surfaces of the base material 60 to be the light guide plate 30, and the main surface 61 in which the plurality of recesses 37 are formed. The coating step S2 for coating the coating layer 40 having antifouling property is included, and in the coating step S2, the coating layer 40 is accumulated at the bottom of the recess 37 thicker than the other portions.

According to this, since the coating layer 40 is accumulated at the bottom of the recess 37 thicker than the other portions, the bottom of the recess 37 is raised. Therefore, it is possible to improve the wiping property when wiping the light guide plate 30.

Further, the bottom portion of the recess 37 may not have a shape according to the design intention depending on the manufacturing method. However, since the bottom portion of the recess 37 is covered with the coating layer 40 which is thicker than the other portions, the portion different from the design intention can be corrected by the coating layer 40.

As a result, it is possible to improve the wiping property in the recess 37 of the light guide plate 30 and to improve the accuracy of the light distribution control in the recess 37.

The surface of the coating layer 40 at the bottom is flat.

According to this, since the surface of the coating layer 40 at the bottom of the recess 37, that is, the surface of the first portion 401 is a flat surface, the surface of the first portion 401 is a flat surface parallel to the surface outside the recess 37 in the light guide plate 30. can do. Therefore, the surface of the first portion 401 can reflect light in the same manner as the surface outside the recess 37, and can reflect light in a direction according to the design intention.

Further, the coating layer 40 contains a material having light diffusivity.

Here, when the concave portion 37 is formed by laser processing, the surface thereof becomes smooth and becomes a mirror surface, and the light reflected from the portion has higher brightness than the other portions. Therefore, even if the coating layer having no light diffusing particles covers the recess 37, the surface of the coating layer is also a mirror surface like the surface of the recess, so that the light reflected from the portion is more than the other portions. Also the brightness becomes high. If the brightness varies, the appearance of the light guide plate 30 at the time of illumination deteriorates.

By the way, as described above, the thickness of the coating layer 40 is different between the bottom portion in the recess 37 and the other portion. When the coating layer 40 contains a material having light diffusivity (light diffusing particles), the distribution of the light diffusing particles is also large in the thick portion of the coating layer 40 and small in the thin portion. A large amount of light is diffused in the portion where the coating layer 40 is thick, that is, the bottom of the recess 37, and the light is not so diffused outside the portion where the coating layer 40 is thin, that is, the recess 37. Since the variation in brightness is made uniform in this way, it is possible to suppress deterioration of the appearance of the light guide plate 30 during lighting.

Further, the recess 37 is formed in a substantially frustum shape.

As described above, the ideal shape of the concave portion that reflects light is a cone shape. Even if an attempt is made to form a cone-shaped recess by laser machining, a substantially frustum-shaped recess 37 is formed as a result. Even if the substantially frustum-shaped recess 37 is formed in this way, the coating layer 40 is thicker than the other portions at the bottom of the recess 37, so that the light guide plate 30 can be wiped off in the recess 37. And the accuracy of the light distribution control in the recess 37 can be improved.

Further, the depth D1 from the surface of the coating layer 40 outside the recess 37 to the surface of the coating layer 40 at the bottom is 3.5 times or less the opening diameter W1 in the recess 37.

According to this, since the depth D1 is 3.5 times or less of the opening diameter W1 in the recess 37, the bottom portion of the recess 37 can be appropriately raised, and the wiping property in the recess 37 and the recess 37 are improved. It is possible to improve the accuracy of the light distribution control in a well-balanced manner.

[Modification 1]
FIG. 7 is an enlarged cross-sectional view showing a part of the light guide plate 30B according to the first modification. In the above embodiment, the case where the coating layer 40 is coated only on the reflective surface 33 of the light guide plate 30 is illustrated. In this modification 1, the case where the second coating layer 41 is also coated on the exit surface 32 of the light guide plate 30B is illustrated. In the following description, the description may be omitted in the same parts as those in the above embodiment.

As shown in FIG. 7, the exit surface 32 of the light guide plate 30B is uniformly coated with the second coating layer 41 over the entire surface. The second coating layer 41 is an antifouling coating layer that does not contain a light diffusing material. As described above, in the light guide plate 30A, a plurality of recesses 37 are formed only on the reflective surface 33 and the coating layer 40 is coated, and the exit surface 32 does not contain a material having light diffusivity. A second coating layer 41 having antifouling property is coated.

According to this, the second coating layer 41 can enhance the antifouling property of the exit surface of the light guide plate 30B. Here, as described above, since the light is diffused by the coating layer 40, it is not necessary to include the light diffusing material in the second coating layer 41. Therefore, the cost of the second coating layer 41 can be suppressed.

[Other]
The lighting device 10 and the light guide plate 30 according to the present invention have been described above based on the above-described embodiments and modifications 1 and 2, but the present invention is limited to the above-described embodiments and modifications 1 and 2. It's not something.

For example, in the above embodiment, the case where a plurality of recesses 37 are formed only on one main surface of the light guide plate 30 is illustrated, but a plurality of recesses are formed on both of the pair of main surfaces of the light guide plate. May be good.

Further, in the above embodiment, the case where the surface of the first portion 401 of the coating layer 40 is flat is illustrated, but the surface of the first portion 401 may be non-planar. Even in this case, the bottom portion of the recess 37 can be raised, and a portion different from the design intention can be corrected by the coating layer.

Further, in the above embodiment, the case where the entire second portion 402 in the coating layer 40 has a uniform thickness has been illustrated. However, the portion of the second portion 402 in the recess 37 does not have to have a uniform thickness as long as it is thinner than the thickness of the first portion 401.

In addition, it is realized by arbitrarily combining the components and functions in each embodiment within the range obtained by applying various modifications to each embodiment and the gist of the present invention. Forms are also included in the present invention.

10 Lighting device 30, 30A, 30B Light guide plate 32 Exit surface (main surface)
33 Reflective surface (main surface)
37, 37A, 37B Recess 40 Coating layer 41 Second coating layer 60 Base material 61 Main surface S1 Laser processing process S2 Coating process

Claims (8)

A light guide plate in which a plurality of recesses are formed on at least one of a pair of main surfaces facing each other.
The main surface on which the plurality of recesses are formed is coated with a coating layer having antifouling properties.
The bottom portion of the recess is provided with a first portion in which the coating layer is accumulated thicker than the other portions.
A light guide plate provided with a second portion in which the coating layer is formed to have a uniform thickness in a portion of the recess above the bottom portion. The light guide plate according to claim 1, wherein the surface of the coating layer at the bottom is flat. The light guide plate according to claim 1 or 2, wherein the coating layer contains a material having light diffusivity. Of the pair of main surfaces, only one of the main surfaces is formed with the plurality of recesses, and the coating layer is coated.
The light guide plate according to any one of claims 1 to 3, wherein the other main surface is coated with a second coating layer having antifouling property which does not contain a material having light diffusing property. The light guide plate according to any one of claims 1 to 4, wherein the recess is formed in a substantially frustum shape. The method according to any one of claims 1 to 5, wherein the depth from the surface of the coating layer outside the recess to the surface of the coating layer at the bottom is 3.5 times or less the opening diameter in the recess. Light guide plate. The light guide plate according to any one of claims 1 to 6,
A light source that causes light to enter an incident surface between the pair of main surfaces of the light guide plate,
Lighting device equipped with. A laser machining process in which a plurality of recesses are formed by laser machining on at least one of a pair of main surfaces of a base material to be a light guide plate.
A coating step of coating a coating layer having antifouling property on the main surface on which the plurality of recesses are formed is included.
Wherein in the coating step, the bottom of the recess, pooled thicker the coating layer than other parts, the method of manufacturing a over parts than the bottom, you form the coating layer with a uniform thickness the light guide plate.

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