TW201710059A - Production method for light guide plate - Google Patents

Abstract

The objective of the invention is to produce a light guide plate on which shapes such as dot patterns can be accurately applied, and, despite being thin, has high strength, is readily handled, and can be put into practical use. The production method for a polycarbonate light guide plate comprises steps of: rotating a first roll and a second roll while sandwiching a sheet-form polycarbonate between a flexible support and the second roll so as to apply pressure while co-transporting the flexible support, thereby pressing the sheet-form polycarbonate against the second roll; and causing the sheet-form polycarbonate pressed against the second roll and supported on the surface of the second roll by the flexible support to be transported in the rotation direction of the second roll, and separating the sheet-form polycarbonate from the flexible support, at a position where the rotation angle of the second roll is 45 to 150 DEG, as referenced from the position where the surfaces of the first roll and the second roll are closest to one another.

Description

Light guide plate manufacturing method

The present invention relates to, for example, a smart phone, a mobile phone, a mobile terminal, a portable information terminal (PDA), a tablet type personal computer (PC), a notebook PC (Pesonal Computer), a vehicle instrument panel, and a PC. a backlight device using a liquid crystal display panel such as a monitor; and a backlight of a keyboard such as a smart phone, a mobile phone, a mobile terminal, a portable information terminal (PDA), a tablet type personal computer (PC), a notebook PC, or the like A method of manufacturing a light guide plate used inside a lighting device such as a device.

A light guide plate that diffuses light entering from the side and emits light from the surface is used as a backlight device such as a liquid crystal display panel. Since the light guide plate emits light that is incident from the side surface and propagates inside from the surface of the light guide plate, generally, a shape such as a dot pattern is formed on the surface of the light guide plate.

Lighting devices that use light guides need to be lighter, thinner, and less expensive. Therefore, the light guide plate is required to further thin the thickness, and the shape of the dot pattern or the like is more accurately formed (improving the shape imparting property), and the productivity of the light guide plate is improved. In the past, the light guide plate was manufactured by injection molding, extrusion processing, or the like, and various processes were performed.

Patent Document 1 describes a light guide plate having a convex portion on both sides and a method of manufacturing the same. Patent Document 1 discloses a light guide plate having a base portion having a light-transmissive sheet shape, and a portion which is a projection on each of a front surface and a back surface of the base portion, and a portion which is a projection on one surface includes a material similar to the base portion. A melt-extruded resin such as a polymer resin having an alicyclic structure is formed on the other surface and is a convex portion including an acrylic ultraviolet curable resin or the like. Radiation-hardening resin (refer to Patent Document 1 [Technical Solution 1], [0009], [0026]). In Patent Document 1, the thickness of the light guide plate can be set to 500 μm or less (see Patent Document 1 [0036] and [FIG. 5]). Patent Document 1 describes a method of producing such a light guide plate by melt extrusion processing using a sleeve method (see Patent Documents 1 [0037] to [0038], [Fig. 7] to [Fig. 8].

Patent Document 2 describes an optical sheet having a thin double-sided light guide plate and a method of manufacturing the same. Patent Document 2 describes an optical sheet in which a plurality of light guide plates are provided, and a first resin is extruded in a nip between a first pressure roller and a first pattern forming roller to form a surface having a pattern not formed. a first layer on the surface formed by the pattern; a nip between the second layer forming roller and the second pressure roller; and a nip between the second pressure roller and the second pattern forming roller The second layer is extruded on the surface on which the pattern of the first layer is not formed, and the second layer having the patterned surface is formed, and the first layer and the second layer which are integrated include a plurality of light guide plate patterns (refer to Patent Document 2 [ Technical solution 1]). Patent Document 2 describes that the thickness of the optical sheet is from 0.05 mm to about 2 mm (see Patent Document 2 [Technical Solution 4]). Patent Document 2 discloses 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 discloses polycarbonate, PMMA (Polymethylmethacrylate), and a polyolefin-based polymer as a molten resin (see Patent Document 2 [0041]).

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2015-69849

Patent Document 2: Japanese Patent Laid-Open Publication No. 2012-68633

In Patent Documents 1 and 2, a method of producing a thinner light guide plate by extrusion molding is described. However, the shape impartability (transferability) of a pattern such as the shape of the formed pattern is not disclosed.

Further, Patent Documents 1 and 2 exemplify the use of a resin. However, if the thickness is reduced to the thickness of the polycarbonate light guide plate of the present invention, for example, the acrylic resin is soft and easily broken, and thus it is practically impossible to use it. When a light-guide plate having a small thickness is produced using an acrylic resin, it is necessary to combine with other substrates for the purpose of strength in order to be practically used. Therefore, in actuality, in the examples, the specific method of producing the resin is not disclosed, and Patent Documents 1 and 2 do not disclose the invention of the method for producing a light guide plate which can be practically used by using the materials exemplified.

Considering the practical use of a thinner light guide plate, it is made of a resin of higher strength, which is considered to be better in terms of higher strength and easier operation of the light guide plate, but actually uses such a resin correctly. A method of manufacturing a light guide plate having a shape imparting rate (transfer rate) having a shape such as a dot pattern has not been reported.

When the shape imparting property is insufficient and the desired shape cannot be formed properly on the surface of the light guide plate, the problem of insufficient brightness of the light guide plate is also caused.

Further, in recent years, it has been required to stabilize a light guide plate having a thickness of 600 μm or less and to manufacture it at a lower price. When an acrylic resin or the like is used as described above, there is a problem that the strength is insufficient if the thickness is reduced (more specifically, 600 μm or less).

As a result of intensive research, the inventors of the present invention found that the following method for producing a polycarbonate light guide plate can be manufactured at a lower price and can accurately impart a shape such as a dot pattern. The thickness is thin but the strength is high, and it is easy to handle and can be realistic. The light guide plate used in the method of manufacturing the polycarbonate light guide plate comprises: using a specific thermoplastic resin having a self-standing polycarbonate to obtain a sheet-like polycarbonate in a molten state, a sheet-like polycarbonate and a flexible The specific support of the sexual support is pressed together with a roller having a pattern formed on the surface; the sheet polycarbonate is supported on the flexible support, and is moved and cured on the patterned roll, and then cured The sheet-like polycarbonate is separated from the flexible support; thus completing the present invention.

That is, the present invention provides a method of manufacturing a polycarbonate light guide plate, which includes the following Step: heating and melting the polycarbonate, extruding from the die to obtain a sheet-like polycarbonate; the first roll supporting the flexible support is disposed in parallel with the second roll having a pattern formed on the surface, and is flexible The sexual support system is disposed between the first roller and the second roller and wound around at least a part of the circumferential direction of the second roller, and the first roller and the second roller are used for the flexible support and the second roller. The sheet-like polycarbonate is interposed between the rolls, and the flexible support is accompanied by the sheet-like polycarbonate, and is rotated while being pressed, and the sheet-like polycarbonate is pressed against the second roll; The sheet-like polycarbonate of the second roll is supported (holds) on the surface of the second roll by the flexible support, and travels in the direction of rotation of the second roll, and is closest to the surface of the first roll and the second roll. Based on the position, the sheet-like polycarbonate and the flexible support are separated at a position where the rotation angle of the second roller is 45 to 150°; and the third roller is parallel to the second roller and disposed opposite to the first roller. On the side, the sheet-like polycarbonate passes between the second roll and the third roll, and is supported at least in part in the circumferential direction of the third roll, and the third roll system Rotating manner by taking a sheet of polycarbonate.

In one aspect of the invention, a method of manufacturing a light guide plate is provided, wherein a surface of the first roller has elasticity.

In another aspect, the present invention provides a method of manufacturing a light guide plate, wherein (i) the surface of the flexible sheet that is in contact with the sheet-like polycarbonate is mirror-finished (mirror-treated), and is in the form of a sheet. The surface of the carbonate is formed with a pattern, or (ii) the surface of the flexible sheet which is in contact with the sheet-like polycarbonate is formed in a pattern shape in advance, and a pattern is formed on both surfaces of the sheet-like polycarbonate.

In another aspect, the present invention provides a polycarbonate light guide plate which is produced by the above-described manufacturing method and which has a pattern formed on one side or both sides.

In a preferred aspect, the present invention provides a display device having the above A polycarbonate light guide plate manufactured by a manufacturing method.

In another aspect, the present invention provides a polycarbonate light guide plate having a MVR (Melt Volume Rate, melt volume flow rate: 300 ° C, 1.2 kg) of 10 to 90, and a weight average molecular weight (Mw) of 16,000. ~27000 polycarbonate, and has a thickness of 100 ~ 600μm.

In a further preferred aspect of the invention, there is provided a display device having the above-described polycarbonate light guide plate.

Since the production method of the present invention has the above-described characteristics, it is possible to improve the shape formability (increasing the transfer property from the shape of the formed roll to the shape of the polycarbonate), and to manufacture the precision required for the surface of the light guide plate. The shape of the polycarbonate light guide plate. Thereby, it is possible to manufacture a light guide plate having higher strength, easier operation, and higher brightness at a lower price, and it is possible to manufacture a backlight device with higher brightness. Moreover, since the light guide plate having a thickness of 600 μm or less can be manufactured, a thinner and lighter backlight device can be manufactured at a lower price.

When the surface of the first roll is elastic, the shape formability (transfer rate) can be further improved, and a transfer plate having higher brightness can be produced.

When the surface of the flexible sheet is a mirror surface, it is possible to manufacture a light guide plate having a pattern formed on one side, and when patterning is formed on the surface of the flexible sheet, it is possible to manufacture a pattern guide formed on both sides. Light board.

Polycarbonate light guide plate made of polycarbonate with MVR (melt volume flow rate: 300 ° C, 1.2 kg) of 10 to 90 and weight average molecular weight (Mw) of 16000 to 27000 can be higher in strength and easier to handle. The light guide plate with higher brightness, and furthermore, has a thickness of 100 to 600 μm, so that it can be a thinner and lighter backlight device.

10‧‧‧1st roll

20‧‧‧2nd roller

30‧‧‧3rd roller

40‧‧‧Flexible support

50‧‧‧Flexible support roll-up roll

52‧‧‧roll

54‧‧‧roll

56‧‧‧Flexible support roll-in roller

60‧‧‧T-die

70‧‧‧Metal state sheet polycarbonate

72‧‧‧Cured state sheet polycarbonate

w‧‧‧Width

H‧‧‧height

θ‧‧‧Rotation angle

Fig. 1 schematically shows a method of producing a polycarbonate light guide plate according to a mode of the present invention.

Fig. 2 schematically shows a dot pattern formed on a light guide plate.

Fig. 3 schematically shows a triangular or linear pattern formed on the light guide plate by arranging the triangular prisms so that the side faces are in contact with the plane of the light guide plate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it is not necessary to omit the detailed description. For example, a detailed description of a matter that has been clearly known or a description of a repetitive description of substantially the same components will be omitted. The reason for this is that the following description is avoided to unnecessarily become redundant, making it easier for the operator to understand.

In addition, the following description is provided for the purpose of fully understanding the invention, and therefore is not to be construed as limiting the scope of the claims.

The invention of the aspect of the invention provides a method of producing a polycarbonate light guide plate.

In the present specification, the term "light guide plate" refers to a light guide plate that diffuses light entering from the side and generally emits light from the surface.

The light guide plate is usually, for example, a liquid crystal display panel such as a smart phone, a mobile phone, a mobile terminal, a portable information terminal (PDA), a tablet type personal computer (PC), a notebook PC, a vehicle instrument panel, a PC display monitor, or the like. The backlight device is used internally, for example, in a lighting device such as a smart phone, a mobile phone, a mobile terminal, a portable information terminal (PDA), a tablet type personal computer (PC), a notebook PC, or the like.

The "polycarbonate light guide plate" of the embodiment of the present invention is a light guide plate manufactured using polycarbonate.

The "polycarbonate light guide plate" according to the embodiment of the present invention is produced by using a transparent and self-standing polycarbonate (carbonate resin) as a thermoplastic resin. The polycarbonate is not particularly limited as long as it can be used as a polycarbonate to obtain the polycarbonate light guide plate of the present invention, and an additive or the like can be appropriately contained.

The MVR (melt volume flow rate: 300 ° C, 1.2 kg) of the polycarbonate is preferably from 10 to 90, more preferably from 15 to 60. The MVR of polycarbonate was measured by JIS K7210.

The weight average molecular weight (Mw) of the polycarbonate is preferably from 16,000 to 28,000, more preferably from 18,000 to 25,200.

The weight average molecular weight (Mw) of the polycarbonate is obtained by a value measured by a gel permeation chromatography (GPC) apparatus in terms of monodisperse molecular weight polystyrene. More specifically, an Allied HPLC system manufactured by Waters Corporation of Japan was used as a GPC (Gel Permeation Chromatography) apparatus, and a chromatogram was measured using a UV (ultraviolet) detector. PLgel 5 μm Mixed-C manufactured by Agilent Technologies was used as a chromatography tube. The sample was dissolved in tetrahydrofuran and flowed at a column temperature of 40 ° C at a flow rate of 1 ml/min. Mw was obtained by converting the measured value into a calibration curve of monodisperse molecular weight polystyrene.

In the method for producing a polycarbonate light guide plate according to the aspect of the invention, first, the polycarbonate is heated and melted, and extruded from a die to obtain a sheet-like polycarbonate in a molten state.

The temperature of the polycarbonate extruded from the die is preferably from 230 to 290 ° C, more preferably from 240 to 280 ° C, and particularly preferably from 250 to 270 ° C. When the temperature of the polycarbonate extruded from the die is 230 to 290 ° C, the fluidity is high and the transfer rate is further improved, so that it is preferable.

The die is not particularly limited as long as it can produce the light guide plate of the present invention, and a T-die can be exemplified.

Next, the first roll supporting the flexible support and the second roll having a pattern formed in advance on the surface are prepared, and the center axes of the first roll and the second roll are arranged in parallel with each other. The flexible support is placed so as to be wound between at least a part of the circumferential direction of the second roll between the first roll and the second roll.

The first roll and the second roll are rotated, and a sheet-like polycarbonate in a molten state is interposed between the flexible support and the second roll, and the flexible support is accompanied by the sheet-like polycarbonate. The sheet-like polycarbonate in a molten state was pressed against the second roll.

By pressing against the second roller, the shape formed on the surface of the second roller is transferred and melted The single side of the sheet-like polycarbonate in the state is patterned.

When a flexible support having a pattern formed on the surface in contact with the sheet-like polycarbonate is used, the shape formed on the surface of the flexible support is further transferred to the sheet-like polycarbonate in a molten state. The two sides form a pattern. The shape of the pattern can be the same on both sides or different.

Therefore, a method of manufacturing a patterned light guide plate is also provided, wherein (i) the surface of the flexible sheet which is in contact with the sheet-like polycarbonate is mirror-finished (or mirror-finished), and is in the form of a sheet-like polycarbonate. The surface is formed with a pattern, or (ii) the surface of the flexible sheet which is in contact with the sheet-like polycarbonate is formed in a pattern shape in advance, and a pattern is formed on both surfaces of the sheet-like polycarbonate.

Further, the sheet-like polycarbonate pressed against the second roll is supported by the flexible support and held (or kept in pressure so as not to lower the pressure) on the surface of the second roll, and is applied to the second roll. In the direction of rotation, the sheet-like polycarbonate in a molten state is preferably cooled, and the sheet-like polycarbonate and the flexible support are based on the position closest to the surfaces of the first roll and the second roll. The rotation direction of the roller is separated by a rotation angle of 45 to 150°.

The rotation angle of the second roller at a position where the cured sheet-like polycarbonate and the flexible support are separated is preferably 45 to 150°, based on the position closest to the surface of the first roller and the second roller. Good for 50~135°, especially for 60~120°.

Based on the position closest to the surface of the first roller and the second roller, the rotation angle of the second roller at the position where the cured sheet-like polycarbonate and the flexible support are separated is 45 to 150°, The transfer of the shape is further improved, the transfer property is further improved, and the peeling of the flexible sheet and the sheet-like polycarbonate is more easily performed, which is preferable.

The temperature of the first roll is preferably 5 to 40 ° C, more preferably 5 to 35 ° C, and particularly preferably 10 to 30 ° C.

The temperature of the second roll is preferably from 110 to 180 ° C, more preferably from 120 to 170 ° C, and particularly preferably from 130 to 160 ° C.

The temperature of the first roller is 5 to 40 ° C, and the temperature of the second roller is 110 to 180 ° C. In this case, the transfer property is further improved by the transfer of the shape which is more accurate, and the peeling of the flexible sheet and the sheet-like polycarbonate is more easily performed, which is preferable.

The temperature around the first roll and the second roll is preferably a so-called room temperature (5 to 35 ° C).

The flexible support separated from the sheet-like polycarbonate is only appropriately operated, and the operation is not particularly limited. For example, there is a method of winding back by a coiler, returning to the first roll, and introducing it to the first roll and the second roll, and the like. In the case where a resin film is used as the flexible support, a method of winding up the flexible support by a winder is preferably used.

Further, it is preferable that the third roller is parallel to the second roller (the center axes of the third roller and the second roller are parallel to each other) and disposed on the opposite side of the first roller.

Further, the formed sheet-like polycarbonate is supported between the second roll and the third roll in at least a part of the circumferential direction of the third roll, and the third roll is rotated by receiving the sheet-like polycarbonate.

It is preferable that the sheet-like polycarbonate is not pressed (clamped) between the third roll and the second roll, and the interval between the third roll and the second roll is pulled apart. The interval is not particularly limited as long as the third roller can support at least a part of the sheet-like polycarbonate and can be taken.

The "flexible support" according to the embodiment of the present invention has a sheet form, and can support the sheet-like polycarbonate on the second roll, and the polycarbonate light guide plate of the present invention can be produced. There is no particular limitation.

For the flexible support, for example, a resin film such as a polyester resin film, an acrylic resin film, or a polycarbonate resin film; a stainless steel metal plate, a nickel metal plate, or a surface nickel-based gold-plated copper-based metal can be used. Metal sheets such as thin plates and surface chromium-plated gold-plated metal sheets.

A resin film is preferably used for the flexible support, and a polyester resin film is more preferably used.

The flexible support can be pre-formed on one side thereof. When such a flexible support is used, it is possible to manufacture a light guide plate having a shape formed on both sides. As long as it can make this hair In the case of a light guide plate having a shape formed on both sides, a flexible support body having a shape formed on one side is not particularly limited.

The flexible support body having a shape formed in advance may be, for example, a support having a shape formed on one surface of the flexible support. For example, a photocurable resin such as an acrylic photocurable resin can be used as the resin film such as a polyester resin film, an acrylic resin film or a polycarbonate resin film. a resin film having a shape formed on the surface thereof; a metal sheet having a shape formed on a surface of a metal thin plate such as a stainless steel-based metal sheet, a nickel-based metal sheet, or a copper-based metal sheet by a laser processing method, a gold plating method, a cutting method, or an etching method .

The flexible support having a shape formed in advance is preferably a resin film formed into a shape using a photocurable resin, and more preferably a resin film having a shape formed by using an acrylic photocurable resin on the surface of the polyester resin film. .

The first roll, the second roll, and the third roll in the form of the present invention are generally used for the extrusion molding of a resin, and are not particularly limited as long as the light guide plate of the present invention can be produced.

Further, the first to third rolls are made of any metal, and the surface may be metal or other materials. The surface of the first roll is generally preferably mirrored (or mirror finished). The surface of the second roller is formed into a shape. The surface of the third roller is generally preferably a mirror surface.

The arrangement of the first to third rolls is not particularly limited, and may be horizontal or vertical, and is preferably horizontal.

The first roll of the embodiment of the present invention preferably has elasticity on its surface.

Regarding the elasticity of the first roll, the hardness of the durometer specified in JIS K6253 is preferably 40 to 85, more preferably 50 to 85, and particularly preferably 60 to 80, in accordance with the hardness of the type A durometer.

When the surface of the first roll is elastic, the transfer property is improved by the transfer of the shape of the first roll, and the change in the manufacturing conditions is less likely to occur, and the change in the manufacturing conditions can be absorbed, and the manufacturing can be performed more stably. Therefore, it is better.

In order to provide elasticity to the surface of the first roller, the surface thereof may be covered by an elastomer. Just for When the flexible sheet extruded from the T-die is sandwiched between the flexible sheet supported by the first roll and the second roll, and the elastic body is elastically deformed when pressurized, there is no Specially limited. The surface of the first roll is preferably covered with at least one type of elastomer selected from the group consisting of a lanthanum-based elastic resin and a nitrile rubber-based elastic resin, and more preferably at least one selected from the group consisting of lanthanum-based elastic resins.

As described above, the second roller of the embodiment of the present invention has a shape transferred to the surface of the light guide plate. The shape formed in the second roller is not particularly limited as long as it is a pattern for the light guide plate. For example, a dot pattern, a microlens pattern, or the like is preferable.

The thickness of the polycarbonate light guide plate of the embodiment of the present invention is preferably from 100 to 600 μm, more preferably from 125 to 400 μm, still more preferably from 150 to 300 μm.

When the thickness of the polycarbonate light guide plate is 100 to 600 μm, it is thinner, lighter, and capable of maintaining its strength, and can be practically used.

Further, the thickness of the polycarbonate light guide plate means a portion which does not have the thickness of the pattern forming portion.

The pattern may have two types of convex and concave shapes based on a portion of the unpatterned light guide plate, and preferably has a convex shape.

For example, in FIG. 2, a dot pattern formed on a light guide plate is schematically illustrated.

Further, in FIG. 3, a pattern in which a triangular prism is formed so as to be in contact with the plane of the light guide plate so as to be formed in a linear or groove shape of the light guide plate is schematically illustrated.

Regarding the surface of the pattern that is in contact with the portion of the unpatterned light guide plate, the dimension of the widest portion of the surface is referred to as the "width (w)" of the pattern.

Regarding the surface of the pattern that is in contact with the portion of the unpatterned light guide plate, the dimension of the highest portion from the vertical direction of the surface is referred to as the "height (h)" of the pattern.

Regarding the shape of the pattern, the largest dimension is generally 100 μm or less, preferably 50 μm or less, and the other dimensions are 10% or more.

However, in a direction in which the pattern is grooved or linear, and other directions In the case of a portion having a shape having an extremely long dimension (in the case where the triangular prism is arranged such that its side faces are in contact with the plane of the light guide plate), the size of the portion in the groove direction or the line direction is not considered. The size of a portion in a direction perpendicular to the groove direction or the line direction and parallel to the plane of the sheet-like polycarbonate is referred to as "width (w)". The size of a portion perpendicular to the groove direction or the line direction and perpendicular to the plane of the sheet-like polycarbonate is referred to as "height (h)". Among the "width" and "height", the largest dimension is generally 100 μm or less, preferably 50 μm or less.

In the manufacturing method of the aspect of the present invention, the transfer rate of the formed pattern is examined in consideration of both the transfer rate of the width of the bottom surface of the formed pattern and the transfer rate of the height. Here, the width and height of the formed pattern are as described above.

For example, if it is a dot shape, it is substantially hemispherical, and therefore the width of the bottom surface refers to the largest diameter among the bottom surfaces of the circular shape, and the height refers to the height of the substantially highest portion.

For example, if the triangular prism is arranged in a line or groove pattern in such a manner as to be in contact with the surface of the roller so that the side faces are in contact with each other, the side of the triangular prism is a very elongated rectangle, and the width thereof refers to the side of the triangular prism. The length of the shorter side, the height refers to the height of the bottom surface of the triangular prism from one side of the triangle to the apex of the opposite.

In the case of a dot pattern, the transfer rate of the diameter of the bottom surface of the dot shape is preferably from 90 to 100%, more preferably from 92 to 100%, and particularly preferably from 95 to 100%. The transfer rate of the height of the dot shape is preferably from 80 to 100%, more preferably from 85 to 100%, and particularly preferably from 90 to 100%. Hereinafter, this is also referred to as transfer rate 1.

When the transfer rate of the diameter of the bottom surface of the circular shape of the dot shape is 90 to 100%, and the transfer rate of the height of the dot shape is 80 to 100%, it is preferable to manufacture a light guide plate having a higher brightness.

If the pattern is linear or groove-shaped in a direction parallel to the surface of the roller and the triangular column is connected by the side surface thereof, the length of the shorter side of the side surface of the triangular prism is turned. The printing ratio is preferably from 90 to 100%, more preferably from 92 to 100%, and particularly preferably from 95 to 100%. The transfer rate of the bottom surface of the triangular prism from one side of the triangle to the height of 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 transfer rate 2.

The transfer rate of the length of the shorter side of the side of the triangular prism is 90 to 100%, and when the transfer rate of the bottom of the triangular column from the one side of the triangle to the height of the opposite vertex is 70 to 100%, It is preferred to manufacture a light guide plate of higher brightness.

The manufacturing method of the aspect of the present invention will be described more specifically and in detail with reference to the accompanying Fig. 1.

Fig. 1 is a view schematically showing a method of manufacturing a light guide plate according to a mode of the present invention.

The three rolls of the first roll 10, the second roll 20, and the third roll 30 are arranged in parallel with each other in this order.

The flexible support 40 is wound up from the take-up roll 50, supported by the first roll 10, supported between the first roll 10 and the second roll 20, supported by the second roll, and then separated from the second roll and introduced to the roll 52. The roller 54 is wound by the winding roller 56. The surface of the first roller 10 is mirror-finished (or mirror-finished). The surface of the first roller may also have elasticity.

The second roller 20 has a shape formed on the surface thereof.

The surface of the third roller 30 is mirror-finished (or mirror-finished).

The molten polycarbonate is extruded from the T-die 60 in the form of a molten sheet of polycarbonate 70. The first roller 10 and the second roller 20 rotate, and the sheet-like polycarbonate 70 is sandwiched between the flexible support 40 and the second roller 20 and pressurized together with the accompanying flexible support. The sheet-like polycarbonate 70 is pressed against the second roll, and the shape of the second roll 20 is transferred to the sheet-like polycarbonate 70.

The sheet-like polycarbonate 70 pressed against the second roller 20 is supported by the flexible support 40 on the surface of the second roller 20 and travels in the direction of rotation of the second roller 20. It is preferred that the inter-sheet polycarbonate 70 be cured. The sheet-like polycarbonate 72 and the flexible support 40 are rotated by 45 to 150° in the rotation direction of the second roller 20 with respect to the position closest to the surface of the first roller 10 and the second roller 20. The position of the angle (θ) is separated.

The flexible support 40 is wound by the take-up rolls 56 by the rolls 52 and 54. The flexible support 40 may also not be wound by the take-up roll 56, for example, returned to the take-up roll 50.

The sheet-like polycarbonate 72 from which the flexible support 40 is separated further moves on the surface of the second roller 20, and is passed between the second roller 20 and the third roller 30, and at least a part of the circumferential direction of the third roller 30 is stand by. The third roller 30 is rotated in such a manner as to receive the sheet-like polycarbonate 72. The sheet polycarbonate 72 can be taken up by another roller (not shown).

The present invention provides a polycarbonate light guide plate which is produced by the above-described manufacturing method and which is formed with a pattern on one side or both sides.

Further, the present invention provides a display device having a polycarbonate light guide plate manufactured by the above manufacturing method.

The present invention provides a polycarbonate light guide plate made of polycarbonate having an MVR (melt volume flow rate: 300 ° C, 1.2 kg) of 10 to 90 and a weight average molecular weight (Mw) of 16,000 to 28,000, and It has a thickness of 100 to 600 μm.

The present invention provides a display device having the above polycarbonate light guide plate.

The polycarbonate light guide plate of the embodiment of the present invention is used, for example, in a backlight device of a liquid crystal display panel and a backlight device such as a keyboard backlight device, and the present invention provides such a lighting device.

Further, such a lighting device is used, for example, as a smart phone, a mobile phone, a mobile terminal, a portable information terminal (PDA), a tablet type personal computer (PC), a notebook PC, an in-vehicle instrument panel, a PC display monitor, and the like. The display device of the present invention provides such a display device.

[Examples]

Hereinafter, the present invention will be described more specifically and in detail by way of examples and comparative examples, but these examples are only one aspect of the invention, and the invention is not limited by the examples.

In addition, in the description of the examples, unless otherwise specified, the portion excluding the solvent is used as a basis for the parts by weight and % by weight.

Example 1

The outer diameter of the screw is 40mm Seamless (no vent) single-axis extruder. A T-die having an effective width of 450 mm of the lip was used as the die. The following three rolls are arranged horizontally in such a manner that the directions of the respective central axes are parallel and used as a cooling roll unit, that is, an elastic roll (first roll) having a width of 500 mm and an outer diameter of 300 mm. And the surface is covered with ruthenium rubber; the metal roll (second roll) is randomly formed on the surface of the roll to have an outer diameter of 50 μm and a depth of 5 μm, and has a width of 500 mm and an outer diameter of 300 mm. Metal roll (3rd roll) with a mirror surface and a width of 500mm and an outer diameter of 300mm .

As the thermoplastic transparent resin, a polycarbonate resin (manufactured by Sutheron Polycarbonate Co., Ltd., weight average molecular weight (Mw): 21,400, MVR: 29) was used.

The following sheet was used as a flexible support, that is, a polyester film having a thickness of 0.125 mm was formed by using an acrylic photocurable resin in the form of a triangular prism having a pitch of 25 μm and a depth of 7 μm in parallel on the surface.

The polycarbonate which is molten at 250 to 270 ° C is extruded from the T-die in the form of molten sheet polycarbonate. The first roller and the second roller are rotated to sandwich the sheet-like polycarbonate between the flexible support and the second roller and are pinched together with the accompanying flexible support, and the shape of the second roller is transferred. To sheet polycarbonate.

The sheet-like polycarbonate is supported on the surface of the second roll by the flexible support and travels in the direction of rotation of the second roll, and the sheet-like polycarbonate is solidified so as to be closest to the surface of the first roll and the second roll. The position is based on the position where the rotation angle of the second roll is 90°, and the cured sheet-like polycarbonate is separated from the flexible support. The flexible support is taken up by a take-up roll through a roller.

The temperature of the first roll is 10 to 30 ° C, and the temperature of the second roll is 140 to 160 ° C. The temperature around the first roll and the second roll is room temperature.

The manufactured polycarbonate light guide plate has a thickness of 0.250 mm. Using the Keyence company The surface of the light guide plate was observed by a digital microscope VHX-2000 (trade name), and the transfer rate (transfer rate 1) was measured. As a result, the transfer rate of the diameter of the bottom surface of the dot shape was 97% to 100%. The transfer rate of the height of the dot shape is 92% to 98%.

The transfer rate (transfer rate 2) is measured in a groove-like or linear pattern in which the triangular prisms are arranged in such a manner as to be in contact with the surface in the direction parallel to the surface, and as a result, the length of the shorter side of the side of the triangular prism is determined. The transfer rate is 98~100%, and the transfer rate of the bottom of the triangular column from the edge of the triangle to the height of the opposite vertex is 95~97%.

Comparative example 1

A polycarbonate light guide plate was produced in the same manner as in Example 1.

However, the sheet-like polycarbonate in a molten state is not supported by the surface of the second roll by the flexible support, and the flexible support is away from the sheet-like polycarbonate. That is, the rotation angle θ at which the sheet-like polycarbonate is supported by the flexible support is substantially 0°.

The surface was returned along a 矽 rubber elastic roller and taken 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 rate was measured. As a result, the transfer rate of the diameter of the bottom surface of the dot shape was 94% to 97%, and the transfer rate of the height of the dot shape was 57%. 69%.

Regarding the linear or groove-like pattern in which the triangular prisms are arranged in such a manner as to be in contact with the side surface in the direction parallel to the surface, the transfer rate of the shorter side of the side surface of the triangular prism is 98 to 100%, and the bottom surface of the triangular prism The transfer rate from one side of the triangle to the height of the opposite vertex is 63 to 68%.

The light guide plates of Examples 2 to 6 and Comparative Examples 2 to 3 were produced in the same manner as in Example 1.

However, there are differences from the first embodiment, and the details and results are collectively shown in Tables 1 and 2.

Further, in Comparative Example 3, an acrylic resin (Mitsubishi Laiyang Co., Ltd.) was used. Manufactured, VH6 (trade name), MFR = 1.7 (JISK7210)) instead of polycarbonate.

If the research examples and the comparative examples are studied, it can be understood that even when the rotation angle is between 45 and 150, even at a thinness of 0.250 mm, a higher transfer rate of 80% or more can be obtained in the height direction of the pattern. A polycarbonate light guide plate is manufactured. Since the production method of the aspect of the present invention utilizes an extrusion molding method, it is easy to manufacture. Further, since the shape can be formed on both surfaces at once, it is possible to more easily manufacture a polycarbonate light guide plate having a shape on both sides.

As described above, the embodiment has been described as an example of the technique of the present invention. Therefore, a detailed description is described.

Therefore, among the constituent elements described in the detailed description, not only the constituent elements necessary for solving the problem but also the constituent elements not necessary for solving the problem are included in order to exemplify the above-described techniques. Therefore, it is not necessary to directly identify such unnecessary constituent elements as necessary in the detailed description.

In addition, the above-described embodiments are intended to exemplify the technical scope of the present invention, and various changes, substitutions, additions, omissions, and the like may be made in the scope of the claims.

[Industrial availability]

The method for producing a light guide plate according to the present invention can greatly reduce an insufficient transfer rate and further stabilize the method of transferring a shape to a resin surface by a conventional method of producing a light guide plate by injection molding or extrusion processing. A light guide plate having a precise shape and having a thickness of 100 to 600 μm is formed on the surface of the light guide plate. Therefore, it is possible to provide a light guide plate having a shape precisely formed on the surface of the light guide plate, and it is possible to achieve high brightness of the backlight device, and thus the industrial use value is extremely high.

10‧‧‧1st roll

20‧‧‧2nd roller

30‧‧‧3rd roller

40‧‧‧Flexible support

50‧‧‧Flexible support roll-up roll

52‧‧‧roll

54‧‧‧roll

56‧‧‧Flexible support roll-in roller

60‧‧‧T-die

70‧‧‧Metal state sheet polycarbonate

72‧‧‧Cured state sheet polycarbonate

θ‧‧‧Rotation angle

Claims (5)

A method for producing a polycarbonate light guide plate, comprising the steps of: heating and melting a polycarbonate, extruding from a die to obtain a sheet-like polycarbonate; and supporting the first roll of the flexible support with the surface The second roller having the pattern formed in advance is disposed in parallel, and the flexible support system is disposed between the first roller and the second roller and wound around at least a part of the circumferential direction of the second roller, and the first roller and the first roller In the second roll, the sheet-like polycarbonate is interposed between the flexible support and the second roll, and the flexible support is accompanied by the sheet-like polycarbonate, and is rotated while being pressurized. The sheet-like polycarbonate is pressed against the second roll; the sheet-like polycarbonate pressed against the second roll is supported by the flexible support on the surface of the second roll, and travels in the direction of rotation of the second roll to The position where the first roller and the second roller are closest to each other is the reference, and the sheet-like polycarbonate and the flexible support are separated at a position where the rotation angle of the second roller is 45 to 150°; and the third roller and the second roller The rolls are parallel and disposed on the opposite side of the first roll, and the sheet-like polycarbonate passes between the second roll and the third roll, and is in the third At least a portion of the circumferential direction is supported by the third roll set to take a sheet of polycarbonate rotate. A method of producing a light guide plate according to claim 1, wherein the surface of the first roller has elasticity. The method of manufacturing a light guide plate according to claim 1 or 2, wherein (i) the surface of the flexible sheet which is in contact with the sheet-like polycarbonate is mirror-finished, and a pattern is formed on one side of the sheet-like polycarbonate. Or (ii) forming a pattern shape on the surface of the flexible sheet which is in contact with the sheet-like polycarbonate, and forming a pattern on both sides of the sheet-like polycarbonate. A polycarbonate light guide plate manufactured by the manufacturing method according to any one of claims 1 to 3, and having a pattern formed on one side or both sides. A display device having a polycarbonate light guide plate manufactured by the manufacturing method according to any one of claims 1 to 3.