CN106716012B - Method for manufacturing light guide plate - Google Patents
Method for manufacturing light guide plate Download PDFInfo
- Publication number
- CN106716012B CN106716012B CN201580010308.7A CN201580010308A CN106716012B CN 106716012 B CN106716012 B CN 106716012B CN 201580010308 A CN201580010308 A CN 201580010308A CN 106716012 B CN106716012 B CN 106716012B
- Authority
- CN
- China
- Prior art keywords
- roller
- polycarbonate
- sheet
- light guide
- guide plate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Abstract
The invention provides a method for manufacturing a polycarbonate light guide plate, which can accurately give a dot pattern and other shapes, has high strength despite of thin thickness, is easy to process and can be practically used. The method comprises the following steps: a first roller and a second roller which nip the sheet-shaped polycarbonate between the flexible support and the second roller and which rotate the flexible support while pressurizing the flexible support while conveying the sheet-shaped polycarbonate, thereby pressing the sheet-shaped polycarbonate against the second roller; the sheet-like polycarbonate which is pressed against the second roller is supported by the flexible support on the surface of the second roller and is conveyed in the direction of rotation of the second roller, and the sheet-like polycarbonate and the flexible support are separated from each other at a position where the angle of rotation of the second roller is 45 to 150 DEG, with reference to the position where the first roller is closest to the surface of the second roller.
Description
Technical Field
The present invention relates to a method for manufacturing a light guide plate used in an illumination device such as a backlight of a liquid crystal display panel of a smartphone, a mobile phone, a mobile terminal, a Personal Digital Assistant (PDA), a tablet Personal Computer (PC), a notebook PC, an in-vehicle instrument panel, a PC display, or the like, or a backlight of a keyboard of a smartphone, a mobile phone, a mobile terminal, a Personal Digital Assistant (PDA), a tablet Personal Computer (PC), a notebook PC, or the like.
Background
A light guide plate that diffuses light entering from a side and emits the light from a surface is used as a backlight of a liquid crystal display panel or the like. Since the light guide plate emits light, which is incident from a side thereof and propagates inside, from a surface of the light guide plate, a shape such as a dot pattern is often formed on the surface of the light guide plate.
Lighting devices using light guide plates are required to be lighter, thinner, and cheaper. Therefore, the light guide plate is required to have a smaller thickness and to form a pattern such as a dot pattern more accurately (to improve shape imparting properties), and to improve productivity of such a light guide plate. Conventionally, various attempts have been made to manufacture a light guide plate by injection molding, extrusion processing, or the like.
Patent document 1 describes a light guide plate having projections on both surfaces and a method for manufacturing the same. Patent document 1 describes a light guide plate having a sheet-like base portion having light permeability, wherein convex portions are formed on the front surface and the back surface of the base portion, respectively, wherein the convex portions on one surface are formed of a melt-extruded resin such as a polymer resin having an alicyclic structure and the same material as the base portion, and the convex portions on the other surface are formed of an ionizing radiation-curable resin such as an acrylic ultraviolet-curable resin (see patent document 1[ claim 1], [0009], [0026 ]). Patent document 1 describes that the thickness of the light guide plate can be set to 500 μm or less (see patent documents 1[0036] and [ fig. 5 ]). As a method for producing such a light guide plate, patent document 1 describes melt extrusion processing by a sleeve method (スリーブ method) (see patent documents 1[0037] to [0038] and [ fig. 7] to [ 8 ]).
Patent document 2 describes an optical sheet having a thin double-sided light guide plate and a method for manufacturing the same. Patent document 2 describes an optical sheet having a plurality of light guide plates: extruding a first resin to a nip between a first pressing roller and a first pattern forming roller, thereby forming a first layer having a non-patterned side and a patterned side; transporting the first layer to a nip between a second pattern forming roll and a second pressure roll; a second layer is extruded onto the non-patterned face of the first layer in a nip between a second pressing roller and a second pattern forming roller, thereby forming the second layer having a patterned face, wherein the integrated first and second layers include a plurality of light guide plate patterns (refer to patent document 2[ claim 1 ]). Patent document 2 describes that the thickness of the optical sheet is 0.05mm to about 2mm (see patent document 2[ claim 4 ]). Patent document 2 describes that such an optical sheet is produced by an extrusion casting method (see patent documents 2[0034] to [0039] and [ fig. 8A ]). Patent document 2 exemplifies polycarbonate, PMMA, and polyolefin polymers as molten resins (see patent document 2[0041 ]).
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2015-6989
Patent document 2: japanese patent laid-open No. 2012 and 68633
Disclosure of Invention
Problems to be solved by the invention
Although patent documents 1 and 2 each describe a method of manufacturing a thinner light guide plate by extrusion molding, nothing is disclosed about shape imparting properties (transferability) of a pattern such as accuracy of the shape of the formed pattern.
Further, although patent documents 1 and 2 exemplify the resins used, when the thickness is made as thin as the polycarbonate light guide plate of the present application, for example, an acrylic resin is soft and easily broken, and thus cannot be practically used. When a light guide plate having a small thickness is manufactured using an acrylic resin, it is necessary to combine the acrylic resin with other base materials for practical use in view of strength. Therefore, in the practical embodiment, a manufacturing method using a specific resin is not disclosed, and therefore patent documents 1 and 2 cannot say that the invention of a manufacturing method of a light guide plate which uses the materials exemplified by them and can be practically used and has a small thickness is disclosed.
In view of the fact that a light guide plate having a small thickness is actually used, it is conceivable that the light guide plate is preferably manufactured using a resin having a higher strength from the viewpoint of higher strength and easier handling of the light guide plate.
If the shape-imparting property is insufficient and the desired shape cannot be formed accurately and sufficiently on the surface of the light guide plate, the luminance of the light guide plate is insufficient.
Further, in recent years, it has been desired to manufacture a light guide plate having a small thickness of 600 μm or less at a lower cost and stably. As described above, when an acrylic resin or the like is used, there is also a problem that if the thickness is made thin (more specifically, if it becomes 600 μm or less), the strength is insufficient.
Means for solving the problems
As a result of intensive studies, the present inventors have found that a method for producing a polycarbonate light guide plate, which is described below, can accurately impart a shape such as a dot pattern and can produce a light guide plate which has a high strength despite its small thickness, is easy to handle, and can be practically used, at a lower cost, and have completed the present invention. The manufacturing method comprises the following steps: using a specific thermoplastic resin such as a polycarbonate having self-standing properties to obtain a sheet-like polycarbonate in a molten state, wherein the sheet-like polycarbonate and a specific support such as a flexible support are pressed together against a roller having a pattern formed on the surface thereof; the sheet-like polycarbonate is solidified while being supported by the flexible support body while running over the roller having the pattern formed thereon, and then the solidified sheet-like polycarbonate is separated from the flexible support body.
That is, the present invention provides a method for manufacturing a polycarbonate light guide plate, comprising:
heating and melting the polycarbonate, and extruding the polycarbonate from a die head to obtain sheet polycarbonate;
a first roller for supporting the flexible support and a second roller having a pattern formed in advance on the surface thereof are arranged in parallel,
the flexible support is disposed so as to pass between the first roller and the second roller and is wound around at least a part of the second roller in the circumferential direction,
the first roller and the second roller are rotated so as to nip the sheet-shaped polycarbonate between the flexible support and the second roller and to press the sheet-shaped polycarbonate against the second roller by rotating the flexible support while conveying the sheet-shaped polycarbonate;
the sheet-like polycarbonate pressed on the second roller is supported on the surface of the second roller by the flexible support (pressure is maintained), and is conveyed along the rotating direction of the second roller, and the sheet-like polycarbonate and the flexible support are separated at a position where the rotating angle of the second roller is 45-150 degrees based on the position where the surfaces of the first roller and the second roller are closest to each other; and
the third roller is parallel to the second roller and is arranged on the opposite side of the first roller,
the polycarbonate sheet is passed between the second roller and the third roller, and supported by at least a part of the third roller in the circumferential direction, and the third roller is rotated so as to pull the polycarbonate sheet.
In one aspect of the present invention, there is provided a method of manufacturing a light guide plate, wherein a surface of the first roller has elasticity.
In another aspect of the present invention, there is provided a method of manufacturing a light guide plate, wherein,
(i) the surface of the flexible sheet in contact with the sheet-like polycarbonate is mirror-finished (mirror-treated), and a pattern is formed on one surface of the sheet-like polycarbonate, or
(ii) A pattern is formed in advance on the surface of a flexible sheet in contact with a sheet-like polycarbonate, and patterns are formed on both surfaces of the sheet-like polycarbonate.
Another object of the present invention is to provide a polycarbonate light guide plate having a pattern formed on one or both surfaces thereof, which is manufactured by the above manufacturing method.
A preferred embodiment of the present invention provides a display device including the polycarbonate light guide plate manufactured by the above-described manufacturing method.
A further gist of the present invention is to provide a polycarbonate light guide plate having a thickness of 100 to 600 μm, which is made of a polycarbonate having an MVR (melt volume flow rate: 300 ℃, 1.2kg) of 10 to 90 and a weight average molecular weight (Mw) of 16000 to 27000.
A further preferred embodiment of the present invention provides a display device including the polycarbonate light guide plate.
Effects of the invention
Since the manufacturing method of the present invention has the above-described features, it is possible to manufacture a polycarbonate light guide plate having improved shape formability (improved shape transferability from a roller having a shape formed thereon to polycarbonate) and having a desired precise shape formed on the surface of the light guide plate. This makes it possible to manufacture a light guide plate having higher strength, easier handling, and higher brightness at lower cost, and further, to manufacture a backlight having high brightness. Further, since the light guide plate having a thickness of 600 μm or less can be manufactured, a thinner and lighter backlight can be manufactured at a lower cost.
When the surface of the first roller has elasticity, a transfer sheet having further improved shape formability (transfer ratio) and higher brightness can be produced.
When the surface of the flexible sheet is a mirror surface, a light guide plate having a pattern formed on one surface thereof can be manufactured, and when the surface of the flexible sheet is a pattern formed thereon, a light guide plate having a pattern formed on both surfaces thereof can be manufactured.
A polycarbonate light guide plate made of a polycarbonate having an MVR (melt volume flow rate: 300 ℃, 1.2kg) of 10 to 90 and a weight average molecular weight (Mw) of 16000 to 27000 can be a light guide plate having high strength, easy handling and high brightness, and can be a thinner and lighter backlight because the thickness is 100 to 600 [ mu ] m.
Drawings
Fig. 1 schematically shows a method for manufacturing a polycarbonate light guide plate according to an embodiment of the present invention.
Fig. 2 schematically shows a dot pattern formed on the light guide plate.
Fig. 3 schematically shows a groove-like or line-like pattern formed by triangular prisms formed on a light guide plate and arranged so that side surfaces thereof are in contact with a plane of the light guide plate.
Detailed Description
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, detailed description beyond necessary limits may be omitted. For example, detailed descriptions of already known matters and repeated descriptions of substantially the same configuration may be omitted. This is to avoid unnecessarily obscuring the following description, as will be readily understood by those skilled in the art.
It should be noted that, since the following description is provided for a person skilled in the art to sufficiently understand the present invention, it should not be construed as being intended to limit the subject matter recited in the claims by these description.
The invention in the form of the present invention provides a method for manufacturing a polycarbonate light guide plate.
In the present specification, the term "light guide plate" refers to an object generally understood as a light guide plate that diffuses light entering from a side and emits the light from a surface.
The light guide plate is generally used in an illumination device such as a backlight of a liquid crystal display panel of a smartphone, a mobile phone, a mobile terminal, a Personal Digital Assistant (PDA), a tablet Personal Computer (PC), a notebook PC, an in-vehicle instrument panel, a PC display, or the like, or a backlight of a keyboard of a smartphone, a mobile phone, a mobile terminal, a Personal Digital Assistant (PDA), a tablet Personal Computer (PC), a notebook PC, or the like.
The "polycarbonate light guide plate" according to the embodiment of the present invention refers to a light guide plate manufactured using polycarbonate.
The "polycarbonate light guide plate" according to the embodiment of the present invention is produced using a transparent polycarbonate (carbonate-based resin) having self-standing properties as a thermoplastic resin. The polycarbonate is not particularly limited as long as it is generally used as a polycarbonate and can obtain a polycarbonate light guide plate which is an object of the present invention, and additives and the like may be appropriately contained.
The MVR (melt volume flow rate: 300 ℃ C., 1.2kg) of the polycarbonate is preferably 10 to 90, more preferably 15 to 60. MVR of polycarbonate was measured according to JIS K7210.
The polycarbonate preferably has a weight average molecular weight (Mw) of 16000 to 28000, more preferably 18000 to 25200.
The weight average molecular weight (Mw) of the polycarbonate is obtained by converting a value measured by a Gel Permeation Chromatography (GPC) apparatus with monodisperse polystyrene. More specifically, the chromatogram was measured with a UV detector using an alliance hplc System manufactured by Waters corporation, japan as a GPC device. As a GPC column, PLgel 5 μm Mixed-C manufactured by Agilent Technologies was used. The sample was dissolved in tetrahydrofuran and allowed to flow at a flow rate of 1ml/min at a column temperature of 40 ℃. The Mw was obtained by converting the measured value with a calibration curve obtained from a monodisperse polystyrene having a molecular weight.
In the method for manufacturing a polycarbonate light guide plate according to the embodiment of the present invention,
first, the polycarbonate is heated and melted, and extruded from a die to obtain a polycarbonate sheet in a molten state.
The temperature of the polycarbonate extruded from the die head is preferably 230 to 290 ℃, more preferably 240 to 280 ℃, and particularly preferably 250 to 270 ℃. The temperature of the polycarbonate extruded from the die is preferably 230 to 290 ℃ because the fluidity is high and the transfer rate is further improved.
The die is not particularly limited as long as it can produce the light guide plate as the object of the present invention, but a T-shaped die may be exemplified.
Next, a first roller for supporting the flexible carrier and a second roller having a pattern formed in advance on the surface thereof are prepared, and the first roller and the second roller are arranged so that the center axes thereof are parallel to each other. The flexible support is disposed so as to pass between the first roller and the second roller and is wound around at least a part of the second roller in the circumferential direction.
The first roller and the second roller are configured to press the molten polycarbonate sheet against the second roller by rotating the flexible support body in a manner that the molten polycarbonate sheet is sandwiched between the flexible support body and the second roller and the flexible support body is conveyed along with the polycarbonate sheet.
By being pressed against the second roller, the shape formed on the surface of the second roller is transferred, thereby forming a pattern on one side of the polycarbonate sheet in a molten state.
When a flexible support having a pattern formed on the surface thereof which is in contact with the sheet-like polycarbonate is used, the shape formed on the surface of the flexible support is transferred, and the pattern is formed on both surfaces of the sheet-like polycarbonate in a molten state. The pattern may be the same or different on both sides.
Therefore, it is also possible to provide a method for producing a light guide plate, wherein (i) the surface of the flexible sheet in contact with the sheet-like polycarbonate is mirror-finished (or mirror-processed), and a pattern is formed on one surface of the sheet-like polycarbonate, or
(ii) A pattern is formed in advance on the surface of a flexible sheet in contact with a sheet-like polycarbonate, and patterns are formed on both surfaces of the sheet-like polycarbonate.
Further, the sheet-shaped polycarbonate pressed against the second roller is supported on the surface of the second roller by the flexible support, is conveyed in the rotational direction of the second roller while maintaining the pressure (or maintaining the pressure so that the pressure does not decrease), is cooled and preferably solidified in the molten state, and is separated from the flexible support at a rotation angle of 45 to 150 ° in the rotational direction of the second roller with reference to the position at which the first roller is closest to the surface of the second roller. The rotation angle of the second roller is preferably 45 to 150 °, more preferably 50 to 135 °, and particularly preferably 60 to 120 ° with respect to the position where the cured sheet-like polycarbonate and the flexible support are separated from each other when the position where the surfaces of the first roller and the second roller are closest to each other is taken as a reference.
In view of more accurate shape transfer, further improved transferability, and easier peeling of the flexible sheet and the sheet-like polycarbonate, the rotation angle of the second roller is preferably 45 to 150 ° with reference to the position where the surfaces of the first roller and the second roller are closest to each other, at which the cured sheet-like polycarbonate and the flexible support are separated from each other.
The temperature of the first roller is preferably 5 to 40 ℃, more preferably 5 to 35 ℃, and particularly preferably 10 to 30 ℃.
The temperature of the second roller is preferably 110 to 180 ℃, more preferably 120 to 170 ℃, and particularly preferably 130 to 160 ℃.
When the temperature of the first roller is 5 to 40 ℃ and the temperature of the second roller is 110 to 180 ℃, the shape is transferred more accurately, the transferability is further improved, and the flexible sheet and the sheet-like polycarbonate are more easily peeled from each other, which is preferable.
The temperature around the first roller and the second roller is preferably room temperature (5 to 35 ℃).
The flexible support separated from the sheet-like polycarbonate is not particularly limited as long as it can be appropriately treated. For example, the following modes are provided: a mode of coiling by a coiling machine; and a mode of returning to the first roller again and guiding the roller between the first roller and the second roller. When the resin film is used as the flexible support, a method of winding the flexible support by a winder is preferably used.
Further, it is preferable that the third roll and the second roll are disposed in parallel (the central axes of the third roll and the second roll are parallel to each other) on the opposite side of the first roll.
Then, the shaped polycarbonate sheet passes between the second roller and the third roller, and is supported by at least a part of the third roller in the circumferential direction, and the third roller rotates so as to pull the polycarbonate sheet.
It is not necessary to pressurize (nip) the polycarbonate sheet between the third roll and the second roll, and it is preferable to leave a space between the third roll and the second roll. The interval is not particularly limited as long as the third roll can support and pull the polycarbonate sheet through at least a part thereof.
The "flexible support" in the embodiment of the present invention is not particularly limited as long as it has flexibility and a sheet-like shape, and can support the sheet-like polycarbonate on the second roller, and can produce the polycarbonate light guide plate as the object of the present invention.
Examples of the flexible support include thin metal plates such as a polyester resin film, an acrylic resin film, a polycarbonate resin film, and other resin films, a stainless steel metal thin plate, a nickel metal thin plate, a surface nickel plating copper metal thin plate, and a surface chromium plating copper metal thin plate.
The flexible support is preferably a resin film, and more preferably a polyester resin film.
The flexible support can be formed in advance into a shape on one surface thereof. When such a flexible support is used, a light guide plate having a shape formed on both surfaces can be manufactured. The flexible support having a shape formed on one surface in advance is not particularly limited as long as the light guide plate having a shape formed on both surfaces according to the embodiment of the present invention can be manufactured.
As the flexible support having a shape formed on one surface in advance, for example, a support having a shape formed on one surface of the flexible support can be exemplified. Examples of the flexible support having such a shape include a resin film having a shape formed by using a photocurable resin such as an acrylic photocurable resin on the surface of a resin film such as a polyester resin film, an acrylic resin film, or a polycarbonate resin film; a thin metal plate having a shape formed by a laser processing method, a plating method, a cutting processing method, an etching method, or the like is used on the surface of a thin metal plate such as a stainless-based thin metal plate, a nickel-based thin metal plate, or a copper-based thin metal plate.
The flexible support having a shape formed on one surface in advance is preferably a resin film having a shape formed of a photocurable resin, and more preferably a resin film having a shape formed of an acrylic photocurable resin on a surface of a polyester resin film.
The first roll, the second roll, and the third roll in the embodiment of the present invention are rolls generally used for extrusion molding of resin, and are not particularly limited as long as the light guide plate of the present invention can be produced.
Furthermore, the first roller to the third roller are made of metal, and the surfaces of the first roller to the third roller can be made of metal or other materials. The surface of the first roller is preferably generally specular (or mirror-finished). The surface of the second roller is formed with a shape. The surface of the third roll is preferably generally specular.
The arrangement of the first to third rollers is not particularly limited, but there are horizontal arrangement, vertical arrangement, and the like, and horizontal arrangement is preferable.
The first roll in the present embodiment preferably has an elastic surface.
The elasticity of the first roller is preferably 40 to 85, more preferably 50 to 85, and particularly preferably 60 to 80 in terms of a durometer hardness specified in JIS K6253 as measured by a type A durometer.
When the surface of the first roller has elasticity, the shape is transferred more accurately, so that the transferability is further improved, and further, the first roller is less likely to be affected by variations in production conditions, and can absorb variations in production conditions, thereby enabling more stable production.
In order to impart elasticity to the surface of the first roller, the surface thereof may be covered with an elastic body. When the molten polycarbonate extruded from the T-die is sandwiched between the flexible sheet supported by the first roller and the second roller and pressurized, there is no particular limitation as long as it is an elastic body that can be elastically deformed. The surface of the first roller is preferably covered with at least one elastomer selected from silicone-based elastic resins, nitrile rubber (ニトリルブチルゴム) -based elastic resins, and the like, and more preferably with at least one elastomer selected from silicone-based elastic resins.
As described above, the second roller according to the embodiment of the present invention has a shape transferred to the light guide plate formed on the surface thereof. The shape formed on the second roller is not particularly limited as long as it is a pattern that can be used for the light guide plate, but for example, a dot pattern, a microlens pattern, or the like is preferable.
The thickness of the polycarbonate light guide plate in the present invention is preferably 100 to 600. mu.m, more preferably 125 to 400. mu.m, and particularly preferably 150 to 300. mu.m.
When the thickness of the polycarbonate light guide plate is 100 to 600 μm, the polycarbonate light guide plate is preferably thinner and lighter in weight, and the strength thereof can be maintained, so that the polycarbonate light guide plate can be practically used.
The thickness of the polycarbonate light guide plate is a portion excluding the thickness of the pattern forming portion.
The pattern may have 2 kinds of projections and depressions based on the portion of the light guide plate where no pattern is formed, but a projection shape is preferable.
For example, fig. 2 schematically shows a dot pattern formed on the light guide plate.
Fig. 3 schematically shows a linear or groove-like pattern formed on the light guide plate, the linear or groove-like pattern being formed by triangular prisms arranged such that the side surfaces of the triangular prisms are in contact with the plane of the light guide plate.
The dimension of the widest part of the surface of the pattern that is in contact with the portion of the light guide plate where no pattern is formed is referred to as the "width (w)" of the pattern.
The dimension of the highest portion in the vertical direction from the surface of the pattern in contact with the portion of the light guide plate where no pattern is formed is referred to as the "height (h)" of the pattern.
The maximum dimension of the pattern shape is usually 100 μm or less, preferably 50 μm or less, and the other dimensions are 10% or more thereof.
In the case where the pattern has a shape in which a portion in one direction has an extremely long dimension, such as a groove or a line, as compared with a portion in the other direction (in the case of a pattern in which triangular prisms are arranged so that side surfaces thereof are in contact with the plane of the light guide plate, which will be described later), the dimension of the portion in the groove direction or the line direction is not considered. The dimension of the portion in the direction parallel to the plane of the sheet-like polycarbonate in the direction perpendicular to the groove direction or the linear direction is referred to as "width (w)". In the direction perpendicular to the groove direction or the linear direction, the dimension of the portion perpendicular to the plane of the sheet-like polycarbonate is referred to as "height (h)". Of the "width" and "height", the largest dimension is usually 100 μm or less, and preferably 50 μm or less.
In the manufacturing method according to the embodiment of the present invention, the transfer ratio of the formed pattern is examined in consideration of both the transfer ratio of the width and the transfer ratio of the height of the bottom surface of the formed pattern. Here, the width and height of the formed pattern are as described above.
For example, if the bottom surface is a dot shape, since the bottom surface is substantially hemispherical, the width of the bottom surface is the largest diameter of the circular bottom surface, and the height is the height of the substantially highest portion.
For example, if the pattern is a linear or groove-like pattern in which triangular prisms are arranged in a direction parallel to the surface of the roller so that the side surfaces of the triangular prisms are in contact with each other, the width of the triangular prisms refers to the length of the short side of the side surface of the triangular prism, and the height refers to the height from one side of the triangle of the bottom surface of the triangular prism to the opposing vertex, since the side surfaces of the triangular prisms are extremely elongated rectangles.
In the dot pattern, the transfer ratio of the diameter of the circular bottom surface of the dot shape is preferably 90 to 100%, more preferably 92 to 100%, and particularly preferably 95 to 100%. The transfer ratio of the height of the dot shape is preferably 80 to 100%, more preferably 85 to 100%, and particularly preferably 90 to 100%. Hereinafter, this is also referred to as transfer ratio 1.
It is preferable that the transfer ratio of the diameter of the circular bottom surface of the dot shape is 90 to 100% and the transfer ratio of the height of the dot shape is 80 to 100%, because a light guide plate with higher brightness can be manufactured.
In the case of a linear or groove-like pattern in which triangular prisms are arranged in a direction parallel to the surface of the roller so that the side surfaces thereof contact each other, the transfer ratio of the length of the short side of the side surface of the triangular prism is preferably 90 to 100%, more preferably 92 to 100%, and particularly preferably 95 to 100%. The transfer rate of the height from one side of the triangle of the bottom surface of the triangular prism to the opposite vertex is preferably 70 to 100%, more preferably 80 to 100%, and particularly preferably 90 to 100%. Hereinafter, this is also referred to as a transfer ratio 2.
It is preferable that the transfer ratio of the length of the short side of the side surface of the triangular prism is 90 to 100%, and the transfer ratio of the height from one side of the triangle of the bottom surface of the triangular prism to the opposing vertex is 70 to 100%, because a light guide plate with higher brightness can be manufactured.
The manufacturing method according to the present invention will be described in more detail with reference to fig. 1 attached.
Fig. 1 schematically shows a method for manufacturing a light guide plate according to an embodiment of the present invention.
The 3 first roll 10, the second roll 20, and the third roll 30 are arranged in this order in parallel with their central axes.
The flexible support 40 is unwound from the unwinding roller 50, supported by the first roller 10, passed between the first roller 10 and the second roller 20, supported by the second roller, separated from the second roller, guided to the rollers 52 and 54, and wound up by the winding roller 56. The surface of the first roller 10 is mirror-finished (or mirror-processed). The surface of the first roller may also be elastic.
The second roller 20 is formed with a shape on its surface.
The surface of the third roller 30 is mirror (or mirror-treated).
The molten polycarbonate is extruded from the T-die 60 as molten polycarbonate sheet 70. The first roller 10 and the second roller 20 rotate, and the sheet-shaped polycarbonate 70 is pressed while being sandwiched between the flexible support 40 and the second roller 20. The polycarbonate sheet 70 is pressed against the second roller, so that the shape of the second roller 20 is transferred to the polycarbonate sheet 70.
The sheet-like polycarbonate 70 pressed against the second roller 20 is conveyed in the rotational direction of the second roller 20 while being supported on the surface of the second roller 20 by the flexible support 40. Preferably, the polycarbonate sheet 70 is cured at this time. The sheet-like polycarbonate 72 and the flexible support 40 are separated at a rotation angle (θ) of 45 to 150 ° in the rotation direction of the second roller 20 with reference to the position where the first roller 10 is closest to the surface of the second roller 20.
The flexible carrier 40 passes through the rollers 52 and 54 and is wound up by the wind-up roller 56. The flexible carrier 40 may be returned to the unwinding roller 50 without being wound up by the winding roller 56, for example.
The polycarbonate sheet 72 separated from the flexible support 40 is further conveyed on the surface of the second roller 20, passes between the second roller 20 and the third roller 30, and is supported by at least a part of the third roller 30 in the circumferential direction. The third roller 30 rotates to pull the polycarbonate sheet 72. The polycarbonate sheet 72 may be wound up by another roll (not shown).
The present invention provides a polycarbonate light guide plate having a pattern formed on one or both surfaces thereof, which is manufactured by the above manufacturing method.
Further, the present invention provides a display device having the polycarbonate light guide plate manufactured by the above manufacturing method.
The present invention provides a polycarbonate light guide plate having a thickness of 100 to 600 [ mu ] m, which is made of a polycarbonate having an MVR (melt volume flow rate: 300 ℃, 1.2kg) of 10 to 90 and a weight average molecular weight (Mw) of 16000 to 28000.
The invention provides a display device with the polycarbonate light guide plate.
The polycarbonate light guide plate according to the aspect of the present invention is used in an illumination device such as a backlight of a liquid crystal display panel and a backlight of a keyboard, and the present invention provides such an illumination device.
Further, the present invention provides a display device such as a smartphone, a mobile phone, a mobile terminal, a Personal Digital Assistant (PDA), a tablet Personal Computer (PC), a notebook PC, an in-vehicle instrument panel, and a PC display.
Examples
The present invention will be described in detail with reference to examples and comparative examples, but these examples are merely one aspect of the present invention, and the present invention is not limited to these examples.
In the description of the examples, unless otherwise specified, the parts without taking the solvent into account are defined as parts by weight and% by weight.
Example 1
A non-vented single-screw extruder having a screw with an outer diameter of 40mm phi was used. A T die having an effective width of the die lip of 450mm was used as the die. The following 3 rollers are horizontally arranged in parallel with each center axis direction and used as cooling roller units: an elastic roller (first roller) having a width of 500mm and an outer diameter of 300mm phi and having a surface covered with silicone rubber; a metal roller (second roller) having a width of 500mm and an outer diameter of 300mm phi, which is disposed so as to form dot shapes having an outer diameter of 50 μm and a depth of 5 μm randomly on the surface of the roller; a metal roller (third roller) having a mirror surface, a width of 500mm and an outer diameter of 300mm phi.
Polycarbonate resins (weight average molecular weight (Mw): 21400, MVR: 29, available from Substilon polycarbonate Co., Ltd.) were used as the thermoplastic transparent resins.
As the flexible support, a sheet having a triangular prism shape with a pitch of 25 μm and a depth of 7 μm was formed in parallel on the surface of a polyester film having a thickness of 0.125mm using an acrylic photocurable resin.
Extruding the polycarbonate melted at 250 to 270 ℃ from a T-die as a molten sheet-like polycarbonate. The first roller and the second roller rotate, and the sheet-shaped polycarbonate is pressed while being sandwiched together with the flexible support between the flexible support and the second roller, whereby the shape of the second roller is transferred to the sheet-shaped polycarbonate.
The sheet-like polycarbonate is supported by the flexible support on the surface of the second roller and is conveyed in the rotational direction of the second roller, the sheet-like polycarbonate is solidified, and the solidified sheet-like polycarbonate is separated from the flexible support at a position where the rotational angle of the second roller is 90 ° with respect to a position where the first roller and the surface of the second roller are closest to each other. The flexible carrier is wound up by a wind-up roll through a roll.
The temperature of the first roller is 10-30 ℃, and the temperature of the second roller is 140-160 ℃. The temperature around the first roller and the second roller was room temperature.
The thickness of the manufactured polycarbonate light guide plate was 0.250 mm. The surface of the light guide plate was observed with a digital microscope model VHX-2000 (trade name) manufactured by Keyence corporation, and the transfer ratio (transfer ratio 1) was measured, and as a result, the transfer ratio of the diameter of the bottom surface of the dot shape was 97% to 100%, and the transfer ratio of the height of the dot shape was 92% to 98%.
The transfer ratio (transfer ratio 2) was measured for a groove-like or line-like pattern in which triangular prisms are arranged in a direction parallel to the surface so that the side surfaces of the triangular prisms are in contact with each other, and as a result, the transfer ratio of the length of the short side of the side surface of the triangular prism was 98 to 100%, and the transfer ratio of the height from one side of the triangle of the bottom surface of the triangular prism to the opposing vertex was 95 to 97%.
Comparative example 1
A polycarbonate light guide plate was manufactured using the same method as example 1.
However, the sheet-shaped polycarbonate in a molten state is not supported on the surface of the second roller by the flexible support, and the flexible support is separated from the sheet-shaped polycarbonate. That is, the rotation angle θ at which the sheet-like polycarbonate is supported by the flexible support and conveyed is substantially 0 °.
The sheet was returned along an elastic roller having a silicone rubber surface and wound up by a winder to produce a polycarbonate light guide plate having a thickness of 0.250 mm.
The surface of the light guide plate was observed in the same manner as in example 1, and the transfer ratio was measured, and as a result, the transfer ratio of the diameter of the bottom surface of the dot shape was 94% to 97%, and the transfer ratio of the height of the dot shape was 57% to 69%.
In a linear or groove-like pattern in which triangular prisms are arranged in a direction parallel to the surface so that the side surfaces thereof are in contact, the transfer ratio of the length of the short side of the side surface of the triangular prism is 98-100%, and the transfer ratio of the height from one side of the triangle of the bottom surface of the triangular prism to the opposing vertex is 63-68%.
Light guide plates of examples 2 to 6 and comparative examples 2 to 3 were produced by the same method as in example 1.
The details and results are shown in tables 1 to 2, which are different from those of example 1.
In comparative example 3, an acrylic resin (VH 6 (trade name), MFR 1.7(JISK7210), manufactured by mitsubishi Rayon co., ltd.) was used instead of the polycarbonate.
[ Table 1]
[ Table 2]
When the examples and comparative examples were examined, it was understood that a polycarbonate light guide plate could be manufactured with a high transfer rate of 80% or more in the height direction of the pattern even with a thickness of 0.250mm at a rotation angle of 45 to 150 °. The manufacturing method of the embodiment of the present invention is easy to manufacture because it uses an extrusion molding method. Further, since the shape can be formed on both surfaces at one time, a polycarbonate light guide plate having a shape on both surfaces can be manufactured more easily.
As described above, the embodiments have been described as examples of the technique of the present invention. Therefore, a detailed description is described.
Therefore, the components described in the detailed description may include not only components necessary to solve the problem but also components unnecessary to solve the problem in order to exemplify the above-described technology. Therefore, it should not be immediately assumed that these unnecessary components are essential because they are described in the detailed description.
Further, since the above-described embodiments are intended to illustrate the technique of the present invention, various changes, substitutions, additions, omissions, and the like can be made within the scope of the claims and their equivalents.
Industrial applicability
The method for manufacturing a light guide plate according to the present invention can significantly improve the transfer rate that is insufficient in the method for transferring a shape to a resin surface by the conventional method for manufacturing a light guide plate by injection molding or extrusion processing, and can stably manufacture a light guide plate having a thickness of 100 to 600 μm in which a precise shape is formed on the surface of the light guide plate. Therefore, a light guide plate having a shape precisely formed on the surface of the light guide plate can be provided, and high luminance of the backlight can be realized, and therefore, the industrial value is extremely high.
Description of the reference numerals
10: first roller
20: second roll
30: third roller
40: flexible carrier
50: unwinding roller for flexible carrier
52 and 54: roller
56: flexible carrier wind-up roll
60: t-shaped die head
70: polycarbonate in the molten state in the form of flakes
72: polycarbonate in the cured state in the form of flakes
w: width of
h: height
Claims (5)
1. A method for manufacturing a polycarbonate light guide plate, comprising:
heating and melting polycarbonate, and extruding the polycarbonate from a die head at 230-290 ℃ to obtain sheet polycarbonate;
a first roller for supporting the flexible support and a second roller having a pattern formed in advance on the surface thereof are arranged in parallel,
the flexible support is disposed so as to pass between the first roller and the second roller and is wound around at least a part of the second roller in the circumferential direction,
a first roller having a temperature of 5 to 40 ℃ and a second roller having a temperature of 110 to 180 ℃ for pressing the sheet-like polycarbonate against the second roller by rotating the flexible support so as to sandwich the sheet-like polycarbonate between the flexible support and the second roller and by pressurizing the flexible support while conveying the sheet-like polycarbonate;
the sheet-shaped polycarbonate which is pressed on the second roller is supported on the surface of the second roller by the flexible support body and is conveyed along the rotating direction of the second roller, and the sheet-shaped polycarbonate and the flexible support body are separated at a position where the rotating angle of the second roller is 45-150 degrees by taking the position where the first roller is closest to the surface of the second roller as a reference; and
the third roller is parallel to the second roller and is arranged on the opposite side of the first roller,
the polycarbonate sheet is passed between the second roller and the third roller, and supported by at least a part of the third roller in the circumferential direction, and the third roller is rotated so as to pull the polycarbonate sheet.
2. The method for manufacturing a light guide plate according to claim 1,
the surface of the first roller has elasticity.
3. The method for manufacturing a light guide plate according to claim 1 or 2,
(i) the surface of the flexible support in contact with the sheet-like polycarbonate is a mirror surface, and a pattern is formed on one surface of the sheet-like polycarbonate, or
(ii) A pattern is formed in advance on the surface of the flexible support body in contact with the sheet-shaped polycarbonate, and a pattern is formed on both surfaces of the sheet-shaped polycarbonate.
4. A polycarbonate light guide plate produced by the production method according to any one of claims 1 to 3, wherein a pattern is formed on one or both surfaces.
5. A display device having a polycarbonate light guide plate manufactured by the manufacturing method according to any one of claims 1 to 3.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/JP2015/073896 WO2017033290A1 (en) | 2015-08-25 | 2015-08-25 | Production method for light guide plate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106716012A CN106716012A (en) | 2017-05-24 |
| CN106716012B true CN106716012B (en) | 2020-03-27 |
Family
ID=56706664
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201580010308.7A Active CN106716012B (en) | 2015-08-25 | 2015-08-25 | Method for manufacturing light guide plate |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP5973110B1 (en) |
| CN (1) | CN106716012B (en) |
| TW (1) | TWI707770B (en) |
| WO (1) | WO2017033290A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6356375B1 (en) * | 2017-12-28 | 2018-07-11 | 日東樹脂工業株式会社 | Method for manufacturing light guide plate |
| CN109228236A (en) * | 2018-09-30 | 2019-01-18 | 深圳市普耐科技有限公司 | A kind of shaped form extrusion molding mould |
| CN109228235A (en) * | 2018-09-30 | 2019-01-18 | 深圳市普耐科技有限公司 | A kind of linear type extrusion molding mould |
| JP7178600B2 (en) * | 2019-03-11 | 2022-11-28 | パナソニックＩｐマネジメント株式会社 | Film structure manufacturing method and manufacturing apparatus |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101788131A (en) * | 2009-01-28 | 2010-07-28 | 住友化学株式会社 | Lgp |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6941056B2 (en) * | 2000-11-13 | 2005-09-06 | Asahi Kasei Kabushiki Kaisha | Light guide and method for producing transparent thermoplastic resin composition for light guide |
| TW200638128A (en) * | 2004-09-30 | 2006-11-01 | Sony Corp | Optical sheet, backlight, and liquid crystal display device |
| WO2006098479A1 (en) * | 2005-03-16 | 2006-09-21 | Fujifilm Corporation | Method of producing resin sheet |
| US20110242848A1 (en) * | 2010-04-06 | 2011-10-06 | SKC Haas Display Film Co., Ltd. | Printed double-sided light guide plate |
| US20110242851A1 (en) * | 2010-04-06 | 2011-10-06 | Skc Haas Display Films Co., Ltd. | Double-sided light guide plate manufactured with patterned rollers |
| JP2012008309A (en) * | 2010-06-24 | 2012-01-12 | Dainippon Printing Co Ltd | Optical sheet, surface light source device, and display device |
| US20120051091A1 (en) * | 2010-08-31 | 2012-03-01 | Skc Haas Display Films Co., Ltd. | Optical sheet manufactured with patterned rollers |
| US20120051704A1 (en) * | 2010-08-31 | 2012-03-01 | SKC Haas Disolay Films Co., Ltd. | Optical sheet having thin double-sided light guide |
| CN103797070B (en) * | 2011-06-28 | 2016-08-24 | 住化斯泰隆Pc有限公司 | Poly carbonate resin composition |
| JP6377887B2 (en) * | 2012-02-17 | 2018-08-22 | 学校法人慶應義塾 | Liquid crystal display |
| US20140093650A1 (en) * | 2012-09-28 | 2014-04-03 | Skc Haas Display Films Co., Ltd. | Method of manufacturing a composite light guide |
| US20140133177A1 (en) * | 2013-04-24 | 2014-05-15 | Light Polymers Holding | Lcd backlight component coatings for reducing light losses and improving in-stack light collimation |
| JP6277650B2 (en) * | 2013-09-30 | 2018-02-14 | 大日本印刷株式会社 | Light guide plate, surface light source device, video source unit, and liquid crystal display device |
-
2015
- 2015-08-25 JP JP2016513560A patent/JP5973110B1/en active Active
- 2015-08-25 WO PCT/JP2015/073896 patent/WO2017033290A1/en active Application Filing
- 2015-08-25 CN CN201580010308.7A patent/CN106716012B/en active Active
-
2016
- 2016-07-18 TW TW105122636A patent/TWI707770B/en active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101788131A (en) * | 2009-01-28 | 2010-07-28 | 住友化学株式会社 | Lgp |
Non-Patent Citations (1)
| Title |
|---|
| Fabrication of dual brightness enhancement structures on light guide plates using UV roll-to-plate imprinting lithography;Jen-Chih Yang等;《Optik》;20121220;3324-3328 * |
Also Published As
| Publication number | Publication date |
|---|---|
| TW201710059A (en) | 2017-03-16 |
| CN106716012A (en) | 2017-05-24 |
| JPWO2017033290A1 (en) | 2017-08-24 |
| WO2017033290A1 (en) | 2017-03-02 |
| JP5973110B1 (en) | 2016-08-23 |
| TWI707770B (en) | 2020-10-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106716012B (en) | Method for manufacturing light guide plate | |
| TW201202768A (en) | Double sided light guide plate manufactured with patterned rollers | |
| US20110242847A1 (en) | Laminated double-sided light guide plate | |
| US20120051091A1 (en) | Optical sheet manufactured with patterned rollers | |
| WO2012102178A1 (en) | Method and apparatus for producing resin film | |
| US20120051705A1 (en) | Optical sheet with laminated double-sided light guide plate | |
| JP2012252906A (en) | Method for manufacturing of light guide plate with protective film | |
| US20120050875A1 (en) | Optical sheet manufactured with micro-patterned carrier | |
| US20110242849A1 (en) | Thin double-sided light guide plate | |
| US20120050874A1 (en) | Optical sheet having printed double-sided light guide plate | |
| US8524126B2 (en) | Method for forming optical film | |
| US20110242850A1 (en) | Double-sided light guide plate manufactured with micro-patterned carrier | |
| TWI426100B (en) | Method of extrusion molding prism film and prism film manufactured by the same | |
| TW201219864A (en) | Optical sheet having thin double-sided light guide plate | |
| JP2011073389A (en) | Method for manufacturing optical film | |
| JP2011104999A (en) | Method for manufacturing surface shape transfer resin sheet | |
| JP2019174636A (en) | Oblique stretched film, polarizer, irregular shaped display and method for manufacturing oblique stretched film | |
| JP2010030192A (en) | Minute shape transfer sheet and method of manufacturing minute shape transfer sheet | |
| JP2012171296A (en) | Method for manufacturing pattern sheet and manufacturing device thereof | |
| KR102468236B1 (en) | laminate | |
| JP2012032647A (en) | Retardation film having light diffusion function, manufacturing method thereof, composite polarizing plate, polarizing plate and backlight unit for liquid crystal display device | |
| JP2011167893A (en) | Method and apparatus for producing three-dimensional pattern sheet and pattern sheet | |
| JP2012212041A (en) | Method of manufacturing anisotropic diffusing film, and anisotropic diffusing film | |
| WO2012102274A1 (en) | Resin-sheet manufacturing method | |
| JP2013158961A (en) | Method of manufacturing resin sheet |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| CB02 | Change of applicant information | ||
| CB02 | Change of applicant information |
Address after: Tokyo, Japan Applicant after: NITTO JUSHI KOGYO CO., LTD. Applicant after: Residence PC Company Limited Address before: Tokyo, Japan Applicant before: NITTO JUSHI KOGYO CO., LTD. Applicant before: Sumitomo Dow Ltd. |
|
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |