CN102165333A - Method for producing optical sheet, optical sheet, and light source unit including optical sheet, display unit - Google Patents

Abstract

A conventional solution means for regulating the temperature of thermoplastic resin under extrusion molding, or a conventional method for regulating the circumferential speed of a roll during extrusion molding cannot reproduce a fine surface molding accurately, and a resulting resin sheet cannot fully achieve the surface molding performance which is designed to achieve various purposes, and thereby an optical sheet using the resin sheet, a light source unit using the optical sheet, and a display unit cannot be developed. A method for producing an optical sheet by subjecting the sheet to surface molding using a molding roll surface-processed for transferring an unever shape, characterized in that the circumferential speed (Vb) of a take-up roll (B) is equal to 103-120% of the circumferential speed (Va) of the molding roll. An optical sheet produced by this production method, a light source unit including the optical sheet, and a display unit are also included in the invention.

Description

The preparation method of optical sheet, optical sheet and the light source cell, the display device that comprise this optical sheet

Technical field

The present invention relates to a kind of preparation method with optical sheet of the surface configuration that is used to bring into play functional precision.In addition, relate to light source cell, the display device that a kind of surface configuration of utilizing the precision of this preparation method preparation has the optical sheet of remarkable influence and contains this optical sheet its performance.

Background technology

Consider that from the viewpoint of thermotolerance, resistance to impact, weight, workability etc. thermoplastic resin is widely used as materials such as timber, metal, glass.Particularly sheet material had been widely used as utilizing the exterior material such as roof Material, outer wall materials of timber, metal etc. in the past; Built-in material such as desktop, inner-wall material; The material of the signboard outside the room etc.Wherein, the transparent thermoplastic resin, because thermotolerance, resistance to impact, the transparency are well, therefore, its sheet material instead the optical material of glass be widely used in the resistance to pressure transparent material of large-scale tank in shock-resistant transparent material purposes that building materials purposes, the automotive window of window material etc. use, aquarium.

The surface configuration of such thermoplastic resin sheet, except level and smooth surface configuration with gloss, also can enumerate the surface configuration of the surface configuration of the embossment that has trickle ridge design or two dimension, three-dimensional ridge design, generally when extrusion molding, utilize transfer roll moulding continuously with systematicness.

These surface configurations are by import the thermoplastic resin sheet that is melt into soft state on metal knurling rolls, on the sheet decorative pattern of this roller of transfer printing and moulding obtains, on the outer peripheral face of described metal knurling rolls, be used to give full play to original design performance decorative pattern and concavo-convex be that shape with upset forms.As concrete disclosed example, can enumerate following patent documentation.

The preparation method of the optical sheet of bad outward appearances such as a kind of temperature of the thermoplastic resin of extruding by adjusting, whole ripple disable, variation in thickness, pleat is disclosed in patent documentation 1.

In patent documentation 2, disclose, by extrusion molding at least one side carried out among the preparation method of surface forming resin sheet of surface forming, the temperature by regulating punch die or be about to is carried out the resin temperature before the surface forming, can moulding correct be concavo-convex.

In patent documentation 3, disclose, having carried out among the preparation method of polycarbonate resin plate of surface forming on the two sides at least by extrusion molding, by the temperature of regulating punch die, the temperature of each chill roll, can be on the two sides transfer surface model effectively.

In addition, in patent documentation 4, disclose, in the preparation method of the thermoplastic resin sheet of not implementing surface forming that has utilized a plurality of rollers, by regulating the peripheral speed of second roller and the 3rd roller, can access variation in thickness and the braking tail off, optical good sheet.

In patent documentation 5, disclose, thermoplastic resin after spuing from punch die, peripheral speed by regulating second roller (format roll) adjacent with first roller (roll), with peripheral speed at the take up roll (draw roll) of the dirty setting of the 3rd roller (stripper roll) that next contacts, become and to carry out surface forming effectively, the warpage of sheet integral body is eliminated, and can access optical good sheet.

In patent documentation 6, disclose, thermoplastic resin after spuing from punch die, peripheral speed by regulating first roller (mirror roller), with the peripheral speed of second roller (format roll) that next contacts, further, can carry out trickle surface forming effectively by on the 3rd roller, setting mirror roller.

The prior art document

Patent documentation

Patent documentation 1: the spy opens the 2003-245966 communique

Patent documentation 2: the spy opens flat 10-180846 communique

Patent documentation 3: the spy opens flat 6-190917 communique

Patent documentation 4: the spy opens the 2003-236914 communique

Patent documentation 5: the spy opens the 2007-216481 communique

Patent documentation 6: the spy opens the 2006-130901 communique

Summary of the invention

But, the surface forming of optical property that use, that have the performance height (for example in the parts of the flat-panel monitor of in recent years liquid crystal type etc., the spacing of high ratio of briquetting, high thickness and precision is the following optical elements of 200 μ m) optical sheet pass through the continuous production that extruder carries out, in the method for the peripheral speed of the roller when regulating extrusion molding in the solution of the resin temperature of the thermoplastic resin in the adjusting extrusion molding of in patent documentation 1-3, putting down in writing or in the content of in patent documentation 4-5, putting down in writing, can not realize.In addition, even make up these disclosures and enforcement merely, utilize this operation also can not obtain stable high ratio of briquetting, the resin sheet of high thickness and precision, it is impossible having utilized the optical sheet of this resin sheet and having utilized the full run-down type light source cell (directly-below light source unit) of this optical sheet, the exploitation of display device.

The present invention finishes in view of such situation, and its purpose is to provide a kind of problem that solves above-mentioned conventional art, gives full play to the preparation method of the optical sheet that has surface configuration of original design performance.In addition, its purpose also is to provide a kind of optical sheet of this preparation method's making and light source cell, display device of having utilized this optical sheet utilized.

As first embodiment that is used to realize described purpose, the invention provides a kind of preparation method of optical sheet, it is characterized in that, make the format roll of optical element forming on sheet carry out among the preparation method of optical sheet of surface forming using through surface working, be Va in peripheral speed with format roll, when being Vb with the peripheral speed of take up roll (draw roll), peripheral speed Vb is the 103-130% of peripheral speed Va.

In addition, as second embodiment, a kind of preparation method of optical sheet is provided, it is characterized in that, in described first embodiment, optical element for ground moulding of coiling direction almost parallel and xsect be the optical element that the peak portion of convex or convex arc shaped and paddy portion that xsect is concavity or concave arc shape alternately are arranged in the roughly rib shape of ordered series of numbers almost parallel.

Further, as the 3rd embodiment, a kind of preparation method of optical sheet is provided, it is characterized in that, in described first, second embodiment, roughly the interval of the peak portion of the optical element of rib shape and peak portion or paddy portion and paddy portion is spaced apart below the 200 μ m.

Zhi Bei optical sheet like this, the moulding repeatability on surface is good, and carries out transfer printing with the shape identical with the design of optics, therefore, has given play to especially the good performance as optical sheet.In addition, used the light source cell of this optical sheet, display device also to give play to good performance.

In addition, the so-called above-mentioned coiling direction traffic direction that is sheet, be the leaf length direction.

As described above, according to the present invention, can prepare the optical sheet of giving full play to original design performance effectively.In addition, Zhi Bei optical sheet of the present invention like this because the moulding on surface and the design transfer printing in the same manner of optics, has been given play to especially the good performance as optical sheet.In addition, used the light source cell of this optical sheet, display device also to give play to good performance.

Description of drawings

Fig. 1 is the key diagram of an example of the preparation section of the resin sheet that utilizes extrusion molding preparation of the present invention;

Fig. 2 is the key diagram of an example that has been carried out the format roll of surface working according to the optical element of rib shape roughly with the coiling direction almost parallel ground with sheet by the mode of moulding;

Fig. 3 is the key diagram of an example of format roll;

Fig. 4 is the key diagram of an example of the preparation section of the resin sheet that utilizes extrusion molding preparation of the present invention;

Fig. 5 is the key diagram of configuration mode that expression can obtain the roller group of Fig. 1, Fig. 4;

Fig. 6 is the key diagram of an example of the mode of expression roughly rib shape lens of the present invention;

Fig. 7 is the key diagram of an example of the mode of expression roughly rib shape lens of the present invention.

Embodiment

Below, implement mode of the present invention about being used to, be described in detail with reference to the accompanying drawings, but the present invention is not limited thereto.

The present invention relates to a kind of at least in the preparation method of the optical sheet that has the optical element (spacing is below the 200 μ m) that is used to bring into play functional precision on the one side.

(in the present invention, " sheet " uses with " film " synonym optical sheet of the present invention, refers to that all thickness is the resin-formed body of 0.05-5mm.Below, unified note is made " sheet ") the preparation method, be applicable to all thermoplastic resins that use in the preparation of sheet in the past.As concrete example, can enumerate tygon, polypropylene, ethylene-propylene copolymer, polystyrene, polyacrylonitrile, acrylonitritrile-styrene resin, Polyvinylchloride, polymethylmethacrylate, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, contain the fluoropolymer resin of ester ring type structure etc.Details as described later.

The basic comprising of＜operation and device 〉

The preparation method of optical sheet of the present invention, can preferably adopt preparation method: make the sheet molten thermoplastic resin that extrudes from extruder gap, obtain the sheet molten thermoplastic resin's that rolled operation by two rollers of first roller and second roller with following operation; The operation that directly makes external successively second roller of the described sheet molten thermoplastic resin who is rolled, the 3rd roller and transfer; Follow operation by take up roll coiling sheet molten thermoplastic resin.

As the extruder that uses among the present invention, the extruder of fountain type single-shaft variant, biaxial type, that twin shaft is above all can use.The oxygen that dissolves in low molecular compound that produces during oligomer moulding when removing polymerization and the extruder and moisture etc. preferably are provided with blow vent.In addition, as the vacuum tightness of blow vent, be preferably below 50,000 handkerchiefs, more preferably below 20,000 handkerchiefs.In addition, consider,, preferably use gear-type pump for the material of the melting mixing that spues quantitatively from the viewpoint of thickness and precision and the roughly moulding of the lens of rib shape.To add the functional layer with UV absorbing properties and antistatic performance etc. from the teeth outwards is purpose, under the situation of multiple stratification, can use the extrusion device of multilayer.During multiple stratification, wedge (feed block) mode is regulated in charging and many menifolds (multimanifold) mode all can be used.In addition, be used for the extruder that multilayer is used, preferably use above-mentioned extruder.As T type punch die, on the stability when guaranteeing to produce continuously, must use throttling rod (choke bar) mode.In addition, consider, preferably use the curved lip of curved lip of screw type or hot bolt type from the viewpoint of thickness and precision.Can also use can be by the automatic T type punch die that has the curved lip of hot bolt type of online thickness measurement machine or gradient monitor feedbacks such as (bank monitor).

＜roller configuration 〉

With Fig. 1 of the present invention is example, and the configuration of the roller of the present invention that is used to implement described embodiment is described.Fig. 1 represents to have the preparation method of following operation: make sheet molten thermoplastic resin that the punch die (1) from extruder the extrudes gap by two rollers of first roller (2) and second roller (3), obtain the sheet molten thermoplastic resin's that rolled operation; The operation that directly makes external successively second roller of the described sheet molten thermoplastic resin who is rolled (3), the 3rd roller (4) and transfer; Then by a pair of sheet molten thermoplastic resin who has peeled off through surface forming from the 3rd roller (4) and the take up roll of transferring (5a, 5b) of being used for.

Because first roller (2) is the important roller that is used to determine the thickness of sheet, therefore be not through surface working roller, but preferably use mirror roller.In addition, be subjected to the inadequate situation of influence, thickness and precision of line pressure, can use the cambered roll of drum type.Second roller (3) is selected from the mirror roller, the mat roll (マ Star ト) that are used for making even surface, be used for the knurling rolls of transfer printing embossment etc., being used for any one of the roller of optical element forming of further being provided with as required.These suitably use according to purpose and get final product; particularly with the damage that prevents sheet, more effectively the light of diffusion back illuminator is the situation of purpose; the preferred mat roll about arithmetic average roughness Ra=0.1-5 μ m, the roller of embossing pattern of using, the particularly preferred knurling rolls of making by sand-blast that use.

The 3rd roller (4) is to make the format roll (with reference to Fig. 2, Fig. 3) of optical element forming on sheet through surface working.Since the objective of the invention is at least one face, to obtain having the optical sheet of accurate optics moulding, therefore, the combination of not selecting second roller (3), the 3rd roller (4) only to constitute respectively by mirror roller, knurling rolls.In Fig. 2, Fig. 3, expression can be with the format roll of optical element forming on sheet of oval rib shape roughly.

The desired location of take up roll so long as thermoplastic resin sheet is sufficiently cooled after indeformable degree when take up roll contacts, is set in any position and all can.The shaping and deformation or the whole position that produces the distortion of bad orders such as warpage or fluctuating of sheet that are set in the surface that sheet can not take place because of the pressure between two take up rolls get final product.In addition, in the present invention, so long as can not damage the concaveconvex shape of resin material, in addition also be difficult to produce the material of the slip of roller, take up roll is made of any materials all can.For example, can adopt the rubber hardness on the surface of stipulating among the JIS K6301 is material of 60-90 degree etc.When the take up roll of such rubber hardness is used on the surface of roller, can not damage the concaveconvex shape of resin material, in addition, be difficult to produce the slip of roller yet, can prepare sheet effectively.The surface configuration of take up roll, so long as do not make the surface configuration distortion that utilizes first, second, third roller moulding, can also be fricton-tight etc. moving disorder ground reel, shape all can arbitrarily.

Between the 3rd roller (4) and take up roll (5a, 5b), from the 3rd roller (4) optical sheet of optical element of having peeled off moulding, carry-over pinch rolls (6) (with reference to Fig. 4) are set near the stripper wire of the 3rd roller (4) more preferably for more successfully.

Carry-over pinch rolls can be the carry-over pinch rolls that can regulate peripheral speed, also can be the carry-over pinch rolls that can not regulate peripheral speed.The preferred roller that can regulate peripheral speed of selecting to be independent of first roller, second roller, the 3rd roller.The peripheral speed of carry-over pinch rolls is generally 0.3 meter/minute-30 meters/minute, and most preferred scope is 0.5 meter/minute-20 meters/minute.Carry-over pinch rolls are the situations that can not regulate the carry-over pinch rolls of peripheral speed, or the situation of not carrying out the adjusting of peripheral speed, usually, consider from the viewpoint of the throughput rate of sheet, set peripheral speed.Under the situation that can regulate peripheral speed, in order to improve mouldability, preferably the ratio with the peripheral speed of take up roll is 98-125%, more preferably 100-115%.The ratio of peripheral speed is during less than this scope, from the traction property variation of the 3rd roller, becomes on the moulding product that it is crooked easily to produce, and loses original purpose, and is therefore not preferred; The ratio of peripheral speed is during greater than this scope, and the reduction (generation current mark) that becomes of the outward appearance of optical sheet is therefore not preferred.

Carry-over pinch rolls further preferably are independent of the roller that can regulate temperature of first roller, second roller, the 3rd roller.The preferable range of the temperature of carry-over pinch rolls is Tg-50 ℃ to Tg+30 ℃, more preferably Tg-30 ℃ to Tg+10 ℃.When temperature is lower than this scope, between carry-over pinch rolls and optical sheet, produces slide mark or may produce the warpage or the pleat of moulding product, thus not preferred; When temperature was higher than this scope, sheet can reduce from the fissility of the 3rd roller sometimes, and perhaps the moulding product can produce crooked.In addition, sector-meeting sometimes adheres on the carry-over pinch rolls, and thickness of slab and surface accuracy can reduce, and is therefore not preferred.

The allocation position of carry-over pinch rolls, condition (extruding force, interval etc.) are as long as be arranged so that sheet from the peeling off and becoming smoothly to the operation of the sheet of take up roll of the 3rd roller, can utilize known method to regulate.

The mode of the configuration of first roller to the, three rollers is not limited to the mode of Fig. 1, for example can also be the mode shown in (a)-(c) of Fig. 5.

In addition, the spatial configuration of format roll (first roller to the, three rollers) can be used in the configuration of arranged perpendicular, horizontal arrangement, tilted configuration and multi-angle any one.The situation of arranged perpendicular can be carried out moulding from any one of last central roll gap and following central roll gap.

The peripheral speed of＜roller 〉

At first, the peripheral speed of first roller is by from the discharge-amount of the thermoplastic resin of punch die with passed through the operation of stable sheet of whole operations and the viewpoint decision of throughput rate.The preferred range of the peripheral speed of first roller is 0.3 meter/minute-30 meters/minute, and most preferred scope is 0.5 meter/minute-20 meters/minute.

The peripheral speed of second roller and the 3rd roller with respect to the peripheral speed of first roller, is preferably 102-104%, 100-110% respectively.In addition, about the gap (t2) of gap (t1), second roller and the 3rd roller of first roller and second roller, preferred t1: t2=100: 60～100, further, more preferably t1: t2=100: 70～95.By selecting such setting, can improve forming stability.The relation of t1 and t2 is during less than this scope, become and easily between second roller and the 3rd roller, produce second inclination, sometimes on the moulding product, produce the defective of striated or produce pleat or further become and be difficult to obtain the balance of thickness of slab precision and transfer printing, thus not preferred; The relation of t1 and t2 is during greater than this scope, have the extruding force deficiency, the transfer printing that come by the 3rd roller strap become inadequate may, therefore not preferred.

With first roller similarly, the peripheral speed Va of the 3rd roller (4) is by from the discharge-amount of the thermoplastic resin of punch die with passed through the operation of stable sheet of whole operations and the viewpoint decision of throughput rate, and the peripheral speed Vb of take up roll (5a, 5b) is by the viewpoint decision of stable surface forming.The setting of peripheral speed Va and peripheral speed Vb is preferably set to the 103-130% that peripheral speed Vb is peripheral speed Va, more preferably is set at the 104-125% of peripheral speed Va, further is preferably set to the 105-120% of peripheral speed Va.Peripheral speed Va and Vb are set at this scope when outer, for example less than 103% o'clock, and bending tablet or from difficulties that becomes such as peeling off of the 3rd roller, sheet is rolled onto on the roller, throughput rate produces obstacle continuously.In addition, the transfer printing that is formed at the lip-deep optical element type of roller becomes not exclusively, becomes to can not get having and the optical sheet that designs same optical characteristics, and is therefore not preferred.In addition, greater than 130% o'clock, by the raising of the tension force between the 3rd roller and the take up roll, becoming was difficult to peel off, and adheres to the resin dregs on the 3rd roller, broke as the basic point sheet, therefore not preferred.In addition, the shape that is formed at the lip-deep optical element type of roller produces skew on Width, and the optical property of the sheet that obtains becomes can not become the such of design, and is therefore not preferred.

The temperature of＜roller 〉

Select the situation of the embodiment of Fig. 1, the thermoplastic resin that the temperature that can regulate first roller to the, three rollers, these temperature are used in according to the present invention is selected.Usually, when sheet carries out moulding, be purpose with heat of cooling plastic resin, the temperature of setting first roller to the, three each roller of roller is lower than the temperature that spues of the thermoplastic resin that spues from punch die.

The temperature that spues is according to the adjustment of punch die.Situation of the present invention, when carrying out moulding as the glass temperature of the thermoplastic resin of main body be Tg (℃) time, the temperature of punch die is set (Td) and is preferably Tg+100 ℃ to Tg+150 ℃, more preferably Tg+110 ℃ to Tg+130 ℃.

The temperature of first roller is Tg-50 ℃ to Tg+20 ℃, more preferably Tg-30 ℃ to Tg+10 ℃.When the temperature of first roller is lower than this scope, the mouldability variation of the lens shape in the 3rd roller, therefore not preferred.In addition, produce by sheet and be wound on the fluctuating on the running obstacle that brings on first roller, surface, the possibility height of disturbance in appearance such as askew, therefore not preferred.On the other hand, when the temperature of first roller is higher than this scope, have to produce slide mark or matrix band and be wound on possibility on first roller, thus not preferred.In addition, produce by the fluctuating of the sheet that obtains, crooked, optical property that disturbance in appearance brings such as thickness is fixing is bad or by with the possibility height of the interruption of service of the external bad sheet that brings of second roller etc., therefore not preferred.

The design temperature T2 of second roller is Tg+20 ℃ to Tg+60 ℃, more preferably Tg+30 ℃ to Tg+50 ℃, and more preferably Tg+40 ℃ to Tg+50 ℃.In addition, be Tg+20 ℃ to Tg+60 ℃ as the design temperature T3 of the 3rd roller of format roll, more preferably Tg+30 ℃ to Tg+50 ℃, more preferably Tg+40 ℃ to Tg+50 ℃.In addition, under the situation of setting as the above-mentioned carry-over pinch rolls of the 4th roller, the design temperature T4 of the 4th roller is preferably Tg-50 ℃ to Tg+30 ℃.Temperature is set under these scopes situation in addition, because sheet is wound up into the running obstacle that brings on the roller, or the fluctuating on the surface of the transfer printing of the optical element sheet that becomes not exclusively, further obtain, disturbance in appearance such as askew, produce the bad possibility height of optical property, therefore not preferred.

The adjustment of roller in the situation of carrying out moulding more than 100 ℃, is preferably used thermal medium oil.In addition, the roll temperature among so-called the present invention is meant the temperature of the roller that can measure.As the temperature that can measure, the temperature of using thermal medium in the adjustment of roll surface temperature or roller is arranged, still, consider the preferred temperature of using the thermal medium that in the adjustment of roller, uses from the viewpoint of operation.

The thickness of sheet has no particular limits, and considers from the aspect of using as optical sheet, is preferably below the 5mm, more preferably below the 3mm, more preferably below the 2mm.

The shape of＜roller, material 〉

In the present invention, first roller, second roller, the 3rd roller, so long as in heating, be cooled to the thermoplastic resin that forms sheet can be adjusted to can the temperature of moulding till before can not produce distortion etc. material get final product preferred usually use metal.These rollers can utilize thermal medium, well heater etc. to be adjusted to temperature arbitrarily respectively independently, and in addition, the rotating speed of roller also is necessary and can regulates independently respectively.

Take up roll so long as do not damage the concaveconvex shape of resin material, the other material that also is difficult for the slip of generation roller, is made of any materials and all can.For example, can adopt the rubber hardness on the surface of stipulating among the JIS K6301 is material of 60-90 degree etc.When the take up roll of such rubber hardness is used on the surface of roller, can not damage the concaveconvex shape of resin material, in addition, be difficult to produce the slip of roller yet, can prepare sheet effectively.The surface configuration of take up roll, so long as can not make the surface configuration distortion that utilizes first, second, third roller moulding, also reel in moving disorder ground such as fricton-tight, shape all can arbitrarily.Can distinguish the rotating speed of the roller of regulating take up roll, first roller to the, three rollers independently.Also can regulate the temperature of take up roll.Take up roll is preferably set to: the sheet surface temperature is below the Tg, is preferably below Tg-30 ℃, also can not carry out adjustment.In addition, also can between the 3rd roller and take up roll, suitably be provided for the roller of the operation of adjustment sheet.

Then, the optical sheet for preparing among the present invention is described.

The thermoplastic resin of＜optical sheet 〉

Constitute the thermoplastic resin of optical sheet related among the present invention, so long as transparent and as the thermoplastic resin that the main composed component of optical sheet has the intensity of appropriateness, just have no particular limits.For example, can use polycarbonate resin; Acrylic resins such as polymethylmethacrylate; Polystyrene, polyvinyl toluene, poly-phenylethylene resin series such as (p-methylstyrenes); MS resin (methyl methacrylate and cinnamic multipolymer); Norbornene resin; Polyacrylate resin; Polyethersulfone resin; The fluoropolymer resin that contains ring structure; Two or more hybrid resin in these etc.The preferred fluoropolymer resin that uses polycarbonate resin, phenylethylene resin series, norbornene resin or contain ring structure.Wherein, polycarbonate resin, because the transparency, thermotolerance, processability are good, and these balance is good, therefore, the preferred especially resin of using as optics.In addition, owing to the optical property of the fluoropolymer resin that contains ring structure is good, therefore, resin that its is also especially preferably used as optical sheet.

Polycarbonate resin obtains dihydric phenol and the reaction of carbonic ester presoma by utilizing interface polycondensation or fusion method.Representational example as dihydric phenol, can enumerate 2, two (4-hydroxy phenyl) propane [common name bisphenol-A], 1 of 2-, two (4-hydroxy phenyl) ethane, 1 of 1-, 1-bis(4-hydroxyphenyl)cyclohexane, 2, two (3-methyl-4-hydroxy phenyl) propane, 2 of 2-, 2-two (3,5-dimethyl-4-hydroxy phenyl) propane, two (4-hydroxy phenyl) sulfide, two (4-hydroxy phenyl) sulfone etc. wherein, are preferably bisphenol-A.These dihydric phenols can use in independent or two or more mixing.

As the carbonic ester presoma, can use carbonyl halides, carbonic ester or haloformate etc., particularly, can enumerate two haloformates of phosgene, diphenyl carbonate or dihydric phenol etc.

, as required, can also use catalyzer, chain terminating agent, be used to prevent the antioxidant etc. of the oxidation of dihydric phenol when utilizing interface polycondensation or fusion method that dihydric phenol and carbonic ester presoma are reacted to prepare polycarbonate resin above-mentioned.In addition, polycarbonate resin can be the branched polycarbonate resin with the polyfunctionality aromatics copolymerization more than the three-functionality-degree, it also can be polyestercarbonate resin with aromatic series or aliphatic two functionality carbonic acid copolymerization, in addition, can also be the potpourri that the two or more polycarbonate resins that obtains is mixed.As the polyestercarbonate resin that uses among the present invention, preferably use by interface polycondensation (generic name: the polyestercarbonate resin that the phosgene method) obtains.In addition, directly the polycarbonate resin of the not melt process resin of extruder or mixer etc. is carried out sheet and extrude, can prevent the variable color that brings by thermal history, therefore preferred.

The molecular weight of polycarbonate resin is represented with viscosity average molecular weigh, is generally 15000-40000, is preferably 18000-35000.So-called viscosity average molecular weigh among the present invention will be by obtaining from specific viscosity (η sp) the substitution following formula that the solution that has dissolved the polycarbonate resin of 0.7g under 20 ℃ the methylene chloride of 100ml is obtained.

ηsp/c＝[η]+0.45×[η] ²c

[η]＝1.23×10 ^-4M ^0.83

(wherein, c=0.7, [η] are limiting viscosity)

Except mentioned component, in the scope of not damaging purpose and effect, can also be in polycarbonate resin as required fusion show other composition of the amount of its effect, for example thermal stabilizers such as phosphorous acid, phosphoric acid, phosphite ester, phosphate, phosphonate ester; Ultraviolet light absorbers such as triazole system, acetophenone system, salicylate system; Fire retardants such as the low-molecular polycarbonate of blueing agent (Block Le one イ Application グ drug), tetrabromobisphenol A, tetrabromobisphenol A, decabromodiphenyl oxide; Adjuvants such as flame retardant such as antimony oxide.

The above-mentioned thermal stabilizer that contains phosphorus, the reduction of the molecular weight in the time of can preventing moulding or the deterioration of tone.Contain the object lesson of the thermal stabilizer of phosphorus as this, can enumerate phosphinate based compounds such as triphenyl phosphinate; Phosphonate ester based compounds such as tributylphosphine acid esters; Phosphinate based compounds such as two (2, the 4-di-tert-butyl-phenyl) diphenyl phosphinate; Phosphonate ester based compounds such as phenyl-phosphonic acid dimethyl ester, wherein, preferred three (2, the 4-di-tert-butyl-phenyl) phosphinate, four (2, the 4-di-tert-butyl-phenyl)-4,4 '-xenyl bisphosphonate and two (2, the 4-di-tert-butyl-phenyl) xenyl phosphonate ester.

These thermal stabilizers can use a kind of or two or more mixing to use.The consumption of this thermal stabilizer, the polycarbonate resin that is preferably with respect to 100 mass parts is the 0.001-0.15 mass parts.

Further, the release property from mould when improving moulding is a purpose etc., can be in polycarbonate resin the fusion fatty acid ester compound.As this fatty acid ester, monohydroxy alcohol that preferred carbon number is 1-20 or polyvalent alcohol and carbon number are the part ester or the full ester of the saturated fatty acid of 10-30.Part ester or full ester as this monohydroxy alcohol or polyvalent alcohol and saturated fatty acid, can enumerate glyceryl monostearate, stearic acid two glyceride, glycerol stearate, stearic acid list sorbitol ester, docosanoic acid list glyceride, the monostearate pentaerythritol ester, pentaerythritol tetrastearate, four n-nonanoic acid pentaerythritol esters, propylene glycolmonostearate, geoceric acid stearyl alcohol ester, palmitic acid palm ester, butyl stearate, methyl laurate, isopropyl palmitate, the xenyl Biphenthrin, sorbitan monostearate, 2-ethylhexyl stearate etc., wherein, preferably use glyceryl monostearate, glycerol stearate, pentaerythritol tetrastearate.The consumption of this fatty acid ester with respect to the polycarbonate resin of 100 mass parts, is preferably the 0.001-0.5 mass parts.

In addition, as the thermoplastic resin that constitutes optical sheet of the present invention, the also preferred fluoropolymer resin that contains ring structure that uses.As the fluoropolymer resin that contains ring structure, has the thermoplastic acrylic multipolymer of ring structure on the preferred main chain.Contain ring structure on the main chain and from the structure of (methyl) acrylic ester monomer.Proportional the adding up to that contain of and ring structure proportional from containing of the structural unit of (methyl) acrylic ester monomer, in multipolymer, preferably contain more than the 50 quality %, more preferably contain more than the 70 quality %, further preferably contain more than the 90 quality %, especially preferably contain more than the 95 quality %, most preferably contain more than the 99 quality %.

The ring structure of main chain has positive birefringence usually, structure from (methyl) acrylic ester monomer has weak negative birefringence, therefore, ring structure positive birefringence of bringing and the negative birefringence of being brought by the structure that comes from (methyl) acrylic ester monomer by main chain are eliminated mutually, also can access the film of low-birefringence after extension.At this, so-called positive birefringence is meant, is undertaken by extension under the situation of molecular orientation at the polymer molecular chain as the composition that constitutes film, shows the big refractive index anisotropy of refractive index change with its equidirectional.On the other hand, so-called negative birefraction is meant, undertaken by extension under the situation of molecular orientation at polymer molecular chain, show that refractive index with its equidirectional diminishes, the refractive index of orthogonal directions becomes big refractive index anisotropy simultaneously in addition as the composition that constitutes film.

Constitute the object lesson of (methyl) acrylic ester monomer of the fluoropolymer resin that contains ring structure, can enumerate (methyl) alkyl acrylates such as (methyl) methyl acrylate, (methyl) ethyl acrylate, (methyl) acrylic acid n-propyl, (methyl) n-butyl acrylate, (methyl) tert-butyl acrylate, the just own ester of (methyl) acrylic acid, (methyl) 2-EHA, (methyl) cyclohexyl acrylate; (methyl) acrylic acid benzyl ester; (methyl) acrylic acid chloromethyl ester; (methyl) acrylic acid 2-chloromethyl ester; (methyl) acrylic acid dicyclopentenyl ethoxy ester; (methyl) acrylic acid two cyclopentene esters; (methyl) acrylic acid 2-hydroxyl ethyl ester; (methyl) acrylic acid 3-hydroxypropyl acrylate; (methyl) acrylic acid 2,3,4, the own ester of 5-pentahydroxy-; (methyl) acrylic acid 2,3,4, the own ester of 5-four hydroxyls etc. can use in these one or more.Wherein, on thermal stability and the good this point of optical characteristics, preferred (methyl) alkyl acrylate, special preferable methyl methyl acrylate.

Constitute the fluoropolymer resin that contains ring structure, can also use the monomer except (methyl) acrylic ester monomer, for example can enumerate styrene, α-styrenic monomers such as hydroxyethylbenzene ethene; Vinyl cyanide; Alkenes such as ethylene methacrylic ketone, ethene, propylene, 4-methyl-1-pentene; Vinyl acetate; Methacrylic alcohol, vinylcarbinol, 2-methylol-allyl alcohol-likes such as 1-butylene; Unsaturated carboxylic acid classes such as acrylic acid, methacrylic acid, crotonic acid; 2-(hydroxyalkyl) acrylate such as 2-(methylol) methyl acrylate, 2-(methylol) methyl acrylate; The N-vinyl pyrrolidone; N-vinylcarbazole etc.These monomers can only use a kind of, also can two or more and usefulness.

Ring structure as main chain, can be with N-substituted maleimide amine or maleic anhydride copolymerization such as phenyl maleimide, benzyl maleimide, cyclohexyl maleimide, methyl maleimides, introduce from the ring structure of N-substituted maleimide amine or from the ring structure of maleic anhydride; Also can be by the cyclization after the polymerization, on main chain, introduce lactonic ring structure, glutaric anhydride structure, glutarimide structure, from the ring structure of N-substituted maleimide amine etc.Consider preferably have from thermotolerance, wherein, on less colored, the good this point of optical characteristics, have the lactonic ring structure on the preferred especially main chain from the ring structure of N-substituted maleimide amine or lactonic ring structure, glutarimide structure.

The preparation method who has the thermoplastic acrylic multipolymer of ring structure on main chain can be suitable for known preparation method.For example, about the preparation method of the acryl resin that contains lactone structure, be documented in that the spy opens the 2006-96960 communique, the spy opens the 2006-171464 communique or the spy opens in the 2007-63541 communique.In addition, about with the thermoplastic acrylic multipolymer of N-substituted maleimide amine copolymer and contain the glutaric anhydride structure or the thermoplastic acrylic multipolymer of glutarimide structure, use and open the preparation method who puts down in writing in 2007-31537 communique, WO2007/26659 communique or WO2005/108438 communique etc. the spy and get final product.

About the lactonic ring structure of main chain, can consider from stability of structure for 4-8 unit ring, more preferably 5-6 unit ring, more preferably 6 yuan of rings.In addition, the lactone structure of main chain is the situation of 6 yuan of rings, can enumerate general formula (1) or the special structure represented in the 2004-168882 communique etc. of opening, on the high this point of polymerization yield in the polymkeric substance before on synthetic main chain, introducing the lactonic ring structure, on the containing of lactonic ring structure that be easy to get proportional high polymkeric substance this point, further with the good this point of copolymerization of (methyl) acrylate such as methyl methacrylate on, be preferably structure with following general formula (1) expression.

(in the general formula, R ¹, R ², R ³Represent independently that respectively hydrogen atom or carbon number are organic residue of 1-20.In addition, organic residue can also contain oxygen atom.)

Containing of ring structure is proportional, in multipolymer, be preferably below the 15 quality %, and 1-15 quality % more preferably, more preferably 3-15 quality % is preferably 5-12 quality % especially, most preferably is 5-10 quality %.Containing of ring structure is proportional during more than 15 quality %, and positive birefringence uprises, and be therefore not preferred.By having described ring structure, thermotolerance, solvent resistance, skin hardness are improved.

The Tg of above-mentioned thermoplastic acrylic multipolymer is preferably more than 110 ℃.More preferably more than 115 ℃, more preferably more than 120 ℃.There is no particular limitation for the upper limit of Tg, considers from mouldability, is preferably below 200 ℃.In addition, the weight-average molecular weight of thermoplastic acrylic multipolymer is preferably 10000-300000,50000-300000 more preferably, and more preferably 100000-250000 is preferably 120000-200000 especially.

The property regulation of＜optical sheet 〉

The thickness of optical sheet of the present invention has no particular limits, and from considering as the optical sheet this point, is preferably below the 5mm, more preferably below the 3mm, more preferably below the 2mm.In addition, can only constitute,, light diffusion layer can also be set in order to regulate light diffusing by transparent resin.Can make light diffusion layer equably or random dispersion optical sheet integral body, only lens section, whole except that lens section, only the light emergence face top layer, only on light entrance face top layer or the middle layer.Light diffusion layer is that the particle of light diffusing is dispersed in the thermoplastic resin and forms, and light is spread on the direction of regulation.

The thickness of light diffusion layer can suitably be regulated according to the thickness of optical sheet, has no particular limits, usually can be for about more than the 0.005mm, below the 5mm.During deficiency 0.005mm, can not give full play to the light diffusion; When surpassing 5mm, surpass the higher limit of the thickness of optical sheet of the present invention, having can not be with the possibility of device overall compactization.

＜light diffusing particle 〉

Optical sheet of the present invention can have the light diffusing particle.As the material of light diffusing particle, for example can enumerate the synthetic resin of (methyl) acrylic resin, phenylethylene resin series, polyurethane series resin, polyester based resin, polysiloxane series resin, fluorine resin, these multipolymers etc.; Glass; Clay compound such as smectite, smalite; Inorganic oxide such as silicon dioxide, aluminium oxide etc.In these materials, preferred especially (methyl) acrylic resin, polysiloxane series resin, silicon dioxide.

The consumption of light diffusing particle, with respect to the thermoplastic resin of the formation optical sheet of 100 mass parts, be preferably 0.005 mass parts above, below 20 mass parts, more preferably 0.01 mass parts above, below 10 mass parts.When consumption was less than 0.005 mass parts, the light that incides optical sheet sometimes can not fully be diffused into had given play to the expectation effect that has added particulate.On the contrary, when consumption surpassed 20 mass parts, it is difficult that the extrusion molding of optical sheet sometimes becomes, and the light quantity that sees through reduces, and brightness reduces.In addition, can also conduct be the laminar structure of the part of optical sheet of the present invention with light diffusion layer with light diffusing particle.At this moment, above-mentioned preferable amount becomes the preferable amount in light diffusion layer.The thermoplastic resin of light diffusion layer can be identical with the thermoplastic resin that constitutes light diffusion layer optical sheet in addition, also can be different.

Be used as under the situation of light diffusing particle at the organic fine particles that will obtain by free radical polymerization, as the starting monomer of particulate, can use (methyl) acrylic acid, (methyl) methyl acrylate, (methyl) ethyl acrylate, (methyl) acrylic acid n-propyl, (methyl) isopropyl acrylate, (methyl) n-butyl acrylate, (methyl) isobutyl acrylate, (methyl) tert-butyl acrylate, (methyl) 2-EHA, (methyl) cyclohexyl acrylate, (methyl) acrylic acid benzyl ester, (methyl) hydroxy-ethyl acrylate, (methyl) esters of acrylic acids such as (methyl) hydroxypropyl acrylate; Styrene, p-methylstyrene (p-メ チ Le ス チ レ Application), vinyltoluene (PVC ニ Le ト Le エ Application), to phenylethylenes such as t-butyl styrene; Maleimides such as N-phenylmaleimide, N-cyclohexyl maleimide, N-benzyl maleimide; (methyl) acrylic amides such as (methyl) acrylamide, N-methylol (methyl) acrylamide; Vinyl cyanides such as (methyl) vinyl cyanide; Two or more mixing a kind of or wherein in the N-vinyl pyrrolidone are used.

In addition, be used as under the situation of light diffusing particle at the crosslinked organic fine particles that will obtain by free radical polymerization, except above-mentioned monomer, as being used for crosslinked starting monomer, can also use polyfunctionality (methyl) acrylate such as ethylene glycol bisthioglycolate (methyl) acrylate, diethylene glycol two (methyl) acrylate, propylene glycol two (methyl) acrylate, neopentyl glycol two (methyl) acrylate, trimethylolpropane tris (methyl) acrylate, double hydroxyethyl bisphenol-A two (methyl) acrylate; Free-radical polymerised crosslinking chemicals such as divinyl oxide base oxethyl (methyl) acrylate, diallyl phthalate, (methyl) allyl acrylate, divinylbenzene; Multi-functional epoxy compounds such as bisphenol-A diglycidyl ether, diethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether; Polyfunctionality isocyanate compounds such as toluene diisocyanate, Xylene Diisocyanate, isophorone diisocyanate; In the functionality methylol compounds such as N-melamine methylol, N-methylol benzoguanamine one or more mix use.

The refractive index of above-mentioned light diffusing particle is different with the refractive index of the thermoplastic resin that constitutes optical sheet or light diffusion layer.When use had the organic fine particles of identical refractive index, light was not refracted, and can not fully improve the even according to coefficient of brightness.But on the other hand, the refractive index of resin is different because of kind, therefore, constitutes different the getting final product of kind of resin with the thermoplastic resin of light diffusing particle.In addition, as the selection of particle, can also mix and use bridging property particle and non-crosslinked particle.

Can also be further in the thermoplastic resin that constitutes light diffusing particle of the present invention or optical sheet fusion antioxidant.Therefore optical sheet that oxidation when antioxidant can suppress by hot briquetting or deterioration are brought or light diffusing particle painted, can more positively bring into play the brightness of the light source cell that has been suitable for optical sheet of the present invention.

As antioxidant, can use known in the past antioxidant.For example can use resistance phenol such as pentaerythrite four [3-(3, the 5-di-tert-butyl-hydroxy phenyl) propionic ester] or octadecyl-3-(3,5-di-t-butyl-1-hydroxy phenyl) propionic ester is antioxidant; Three (2, the 4-di-tert-butyl-phenyl) phosphinate or three [2-[[2,4,8,10-tetra-tert dibenzo [d, f] [1,3,2] two oxa-s phosphorus-6-yl] oxygen] ethyl] amine (ト リ ス [2-[[2,4,8,10-テ ト ラ-t-Block チ Le ジ ベ Application ゾ [d, f] [1,3,2] ジ オ キ サ ホ ス Off エ ピ Application-6-イ Le] オ キ シ] エ チ Le] ア ミ Application) and etc. phosphorus be antioxidant; As pentaerythrite four sulphur such as (3-dodecyl thiopropionates) that sulphur support diethylene two [3-(3,5-di-t-butyl 4-hydroxy phenyl) propionic ester] waits, conduct does not have aromatic rings with aromatic rings is antioxidant; 3-hydroxyl-5, the lactones such as reaction product of 7-di-t-butyl furans-2-ketone and o-xylene are antioxidant; With the reduced form tallow is that the hydramines such as oxidation product of the alkyl amine of raw material are antioxidant; 3,4-dihydro-2,5,7, (4,8,12-trimethyl three decyls)-2H-chromene-vitamin Es such as 6-phenol are antioxidant etc. to 8-tetramethyl-2-.

The consumption of antioxidant is suitably regulated and get final product, usually, is particle with respect to the thermoplastic resin or the light diffusion of 100 mass parts, adds that 0.05 mass parts is above, gets final product about below 0.3 mass parts.

The optical element of＜optical sheet 〉

On at least one surface of optical sheet of the present invention, be formed with lens combination as optical element.So-called lens among the present invention are meant the lens that incident light can be spread or focus in certain angle of visibility, can enumerate the lens independently one by one as prism, perhaps have to a certain degree length and, the roughly rib shape lens of the cross sectional shape of the shape after compoundization of a part that a part, the polished object line of isosceles triangle, scalene triangle, an oval-shaped part, circle have surrounded or these shapes.In addition, so-called roughly rib shape lens are lens that above-mentioned cross sectional shape extends to leaf length direction (coiling direction) continuously.

The situation of lens independently one by one, as long as a lens shape can be diffused into light sheet Width (direction vertical with the leaf length direction) and just have no particular limits, be not limited to prism (side's awl: pyramid), can enumerate cone-shaped lens such as pyrometric cone, pentagonal pyramid, hexagonal awl, circular cone; Near after perhaps cutting off the summit of these cones frustum, hemisphere, cut off half oblate spheroid of rugby etc. along major axis with the face parallel with the bottom surface.The situation of lens independently one by one preferably is carried out to the surface working of forming roll, make each lens by almost parallel be configured on the length direction of optical sheet.

In addition, as long as roughly the cross sectional shape of rib shape lens can be diffused into light sheet Width (direction vertical with the leaf length direction) and just has no particular limits, for example can enumerate the part of isosceles triangle, scalene triangle, circle, an oval part, para-curve, bottom is (with reference to Fig. 6) such as semi-circular shape for rectangle top.The drift angle of isosceles triangle can be for more than 60 ℃, below 120 ℃.In addition, the central angle of the part of circle is not limited to 180 ℃, can regulate making luminous energy be diffused on certain direction.

Each lens need not be identical shape, and as shown in Figure 7, the degree of depth of the height of peak portion and/or paddy portion also can be different, and these different situations also can be certain interval, periodic.Based on optical design separately, optical element correctly surface forming gets final product.

As mentioned above, according to the optical property of design, the peak portion of optical element and paddy portion do not have fixing height, the degree of depth sometimes yet, still, correctly to a certain degree trickle shape of transfer printing, when not being molded on the sheet surface, optical element can not brought into play high optical property.The so-called surface configuration that shows correct transfer printing effect of the present invention, in the shape of lens, arrange, the mean gap of the mean gap of peak portion and peak portion or paddy portion and paddy portion (so-called lenticular spacing) is preferably 10-200 μ m, the scope of 30-160 μ m more preferably, become on sheet by this being set transfer printing correctly, can improve the homogeneity of optical property.In addition, the mean value of the length (so-called lens height) of the vertical line of straight line from peak portion to two adjacent paddy portion of connection, with respect to the mean gap of peak portion and peak portion or the mean gap of paddy portion and paddy portion, be preferably 0.1: 1.0～0.8: 1.0 scope, improving on the optical characteristics this point more preferably 0.3: 1.0～0.7: 1.0 scope.

On at least one surface of optical sheet of the present invention, be formed with a plurality of lens.Can be provided with between the adjacent lenses at interval,, also the compartment of terrain adjacency can be set in order suitably to improve the light diffuser efficiency.In addition, lens can form on the total length of optical sheet, and in order to fix with other parts, the end can directly be the plane also.

Constitute the resin of lens, can use the resin identical with the resin that constitutes optical sheet, lens section also can be different with the resin beyond the lens section, still, are generally identical resin.In addition, in constituting the thermoplastic resin of lens, also can disperse be dispersed in light diffusion layer in identical described light diffusing particle (crosslinked organic fine particles etc.).The long axis direction of this light diffusing particle (crosslinked organic fine particles etc.) is preferably roughly the same with the length direction of optical sheet.

Function beyond the optical element of＜optical sheet is paid 〉

Can in the scope of not damaging aim of the present invention, in optical sheet of the present invention, use ultraviolet light absorber, antistatic agent, lubricant, near infrared ray absorption.Especially preferably this is two-layer setting layer that is formed with the layer that contains ultraviolet light absorber, the layer that contains the electrostatic discharge agent or ultraviolet light absorber on the face of light source side and the layer that contains the electrostatic discharge agent for.That is, can also be formed with layer in the side of one side at least of optical sheet (light diffusion layer) with the effect in addition of light diffusion.The layer that contains ultraviolet light absorber preferably is arranged on the face side relative with light source of first optical sheet at least, the maintenance of the function from the preservation environment that environment or parts are set of various light supply apparatuses, the viewpoint of life-saving are considered, also can be arranged on two surfaces.Similarly, the layer that contains antistatic agent also can only be arranged on the face of first optical sheet, also can be arranged on the two sides.In addition, the first optical sheet integral body can be layer that contains antistatic agent or the layer that contains ultraviolet light absorber.These have the layer of the function different with light diffusion function, give optical sheet of the present invention to reduce the ultraviolet ray of sending from luminophor, to suppress the painted of optical sheet, in addition, suppress static, suppress by the brightness reduction that brings adhering to of dust, the functions such as life-span that perhaps prolong electronic device.

As ultraviolet light absorber and antistatic agent, can use known in the past ultraviolet light absorber and antistatic agent.For example as ultraviolet light absorber, can use benzoic acid phenyl ester is ultraviolet light absorber; The benzophenone series ultraviolet light absorber; Triazine is a ultraviolet light absorber; Benzotriazole is a ultraviolet light absorber; Cyclic imino ester type ultraviolet light absorber; The mixed stocker ultraviolet light absorber that has resistance phenol structure and resistance amine structure in the molecule; The triphenyl cyanoacrylate is a ultraviolet light absorber; Oxalic acid aniline is ultraviolet light absorber; Malonate is low molecule ultraviolet light absorbers such as ultraviolet light absorber; With the dangle polymeric UV absorber (for example, Ha Le ス Ha イ Block リ Star De (registered trademark) of Japanese catalyst society system etc.) of the form combination in the macromolecule of these low molecule ultraviolet light absorbers.Wherein, the triphenyl cyanoacrylate is that ultraviolet light absorber, oxalic acid aniline are that ultraviolet light absorber, malonate are that the absorption of the light of ultraviolet light absorber in the visible region is few, and is therefore preferred.The situation that is used for polycarbonate resin, more preferably oxalic acid aniline is that ultraviolet light absorber and malonate are ultraviolet light absorber.

As antistatic agent, can use ethylene series sulfuric ester or its slaines such as alkyl sulfonic acid, alkyl benzene sulphonate or their Li, Na, Ca, Mg, Zn salt; Anionic surfactants such as the phosphoric acid ester of higher alcohol; Tertiary amine, quaternary ammonium salt, kation are that acrylate derivative, kation are cationic surfactants such as vinyl ether derivant; Alkyl amine is the amphoteric salt of amphoteric salt, carboxylic acid alanine or the sulfonic acid alanine of betaine, the amphoteric surfactantes such as amphoteric salt of alkyl imidazoline; The non-ionic surfactants such as polyoxyethylene adduct of polyol esters of fatty acids, alkyl (amine); Polyamide elastomer such as polyether ester amides or polyesteramide etc.In addition, polyvinyl benzylic type resin cation or polypropylene acid type resin cation etc. also can be used as antistatic agent.

The consumption of ultraviolet light absorber and antistatic agent can suitably be regulated according to each function, still, usually, with respect to the resin of each layer of formation of 100 mass parts, for about the 1-50 mass parts.Layer with function different with these light diffusion functions utilizes hot pressing or cementing agent will make ultraviolet light absorber and antistatic agent be dispersed in the sheet that forms in the thermoplastic resin identical with light diffusion layer to be bonded in optical sheet etc. and to go up and get final product.Perhaps, also can after being coated on the optical sheet, the slurry that will contain ultraviolet light absorber etc. carry out drying or cooling.In addition, also can be with fusion the thermoplastic resin of light diffusing agent, fusion the thermoplastic resin co-extrusion modling of ultraviolet light absorber or antistatic agent.The thickness of these layers can suitably be regulated suitably with each function etc., still, and usually can be for about 1-50 μ m.

The size or the shape of optical sheet of the present invention have no particular limits, and for example matching with the size of liquid crystal indicator or shape gets final product.So, can constitute light source cell with good optical characteristic.In addition, by utilizing usual way, can constitute the good liquid crystal indicator of optical property with light source cell of the present invention and liquid crystal panel combination.

Embodiment

＜about embodiment 〉

＜preparation example 1 〉

With 100 parts polycarbonate resins (" ユ one ピ ロ Application (registered trademark) E2000FN ": the エ of Mitsubishi Application ジ ニ ア リ Application グ プ ラ ス チ Star Network ス society system, glass temperature (Tg)=150 ℃), 0.1 the phosphorus of part is thermal stabilizer (" イ Le ガ Off オ ス (registered trademark) 168 ": チ バ ジ ヤ パ Application society system), with 0.003 Fen De oxazole be fluorescer (" ユ PVC テ Star Network ス (registered trademark) OB ": チ バ ジ ヤ パ Application society system) supply to and have blow vent and gear-type pump, formation with Fig. 1 has in the sheet extruder of three rollers, in the outlet of extruder temperature is 265 ℃, first roll temperature is 140 ℃, second roll temperature is 188 ℃, the 3rd roll temperature is under 193 ℃, and carrying out the punch die width is 1150mm, thickness is the extrusion molding of the optical sheet of 1.2mm.In addition, first roller and second roller use the mirror plane roller, and it can the molded lens spacing be that 100 microns, lens height are the roller (carving in the mode that the direction of lens rib line is parallel with the sense of rotation of roller) of 50 microns roughly oval rib shape lens through engraving that the 3rd roller uses.With the peripheral speed of the 3rd roller is that 2.0 meters/minute, the peripheral speed of take up roll are 2.06 meters/minute runnings that are used to prepare optical sheet.

＜preparation example 2 〉

The peripheral speed except take up roll is 2.6 meters/minute, under all identical condition with preparation example 1, the running that is used to prepare optical sheet.

＜preparation example 3 〉

The peripheral speed except take up roll is 2.3 meters/minute, under all identical condition with preparation example 1, the running that is used to prepare optical sheet.

＜preparation example 4 〉

Be that 125 ℃, second roll temperature are 197 ℃, the 3rd roll temperature are 193 ℃ except first roll temperature, under all identical condition with preparation example 1, the running that is used to prepare optical sheet.

＜preparation example 5 〉

Be that 135 ℃, second roll temperature are 191 ℃, the 3rd roll temperature are 191 ℃ except first roll temperature, under all identical condition with preparation example 1, the running that is used to prepare optical sheet.

＜preparation example 6 〉

In the peripheral speed except take up roll is that 2.3 meters/minute, first roll temperature are that 135 ℃, second roll temperature are that 191 ℃, the 3rd roll temperature are 191 ℃, are being provided with between the 3rd roller and the take up roll and are not regulating temperature, do not regulate the carry-over pinch rolls of peripheral speed, under all identical condition with preparation example 3, the running that is used to prepare optical sheet.

＜preparation example 7 〉

Being 130 ℃ except the carry-over pinch rolls temperature, the running that is used to prepare optical sheet under all identical condition with preparation example 6.

＜preparation example 8 〉

The peripheral speed except carry-over pinch rolls is 2.3 meters/minute, under all identical condition with preparation example 7, the running that is used to prepare optical sheet.

＜preparation example 9 〉

Except using mat roll (alignment diagram surface roughness Ra=4.0 μ m) on second roller, under all identical condition with preparation example 4, the running that is used to prepare optical sheet.

＜preparation example 10 〉

Except using knurling rolls (alignment diagram surface roughness Ra=0.25 μ m) on second roller, under all identical condition with preparation example 4, the running that is used to prepare optical sheet.

＜comparative preparation example 1 〉

The peripheral speed except take up roll is 2.0 meters/minute, under all identical condition with preparation example 1, the running that is used to prepare optical sheet.

＜comparative preparation example 2 〉

The peripheral speed except take up roll is 2.8 meters/minute, under all identical condition with preparation example 1, the running that is used to prepare optical sheet.

＜comparative preparation example 3 〉

The peripheral speed except take up roll is 3.0 meters/minute, under all identical condition with preparation example 1, the running that is used to prepare optical sheet.

＜with reference to preparation example 1 〉

Using mirror roller except first roller and the 3rd roller, second roller use through engraving can the molded lens spacing be 100 microns, lens height be 60 microns roughly oval rib shape lens roller (carving) in the mode that the direction of lens rib line is parallel with the sense of rotation of roller in addition, under all identical condition with preparation example 1, the running that is used to prepare optical sheet.

＜with reference to preparation example 2 〉

Be that 155 ℃, second roll temperature are 210 ℃, the 3rd roll temperature are 210 ℃ except first roll temperature, under all identical condition with preparation example 1, the running that is used to prepare optical sheet.

＜with reference to preparation example 3 〉

Be that 125 ℃, second roll temperature are 145 ℃, the 3rd roll temperature are 165 ℃ except first roll temperature, under all identical condition with preparation example 1, the running that is used to prepare optical sheet.

＜about running 〉

About 6 hours continuous running, carry out following evaluation: from initial imposing a condition, do not apply fine setting, situation note that can steady running does zero; Apply fine setting, situation note that can steady running is made △; Do not apply also that fine setting promptly occurs turning round obstacle and situation about stopping note being done *.The results are summarized in the table 1.

＜about ratio of briquetting 〉

The mensuration of ratio of briquetting is undertaken by following method: measure lenticular spacing and lens height by the SEM photography at the core of the Width of the optical sheet that obtains, calculate the lens height/lenticular spacing of optical sheet, this value is divided by the lens height/lenticular spacing of mould (engraving) roller.For example, because the lenticular spacing of the optical sheet that obtains by embodiment 1 is 98.5 microns, lens height is 48.3 microns, the lenticular spacing of mould (engraving) roller is that 100 microns, lens height are 50 microns, therefore, and (ratio of briquetting)=(48.3/98.5) * 100/ (50/100)=98 (%).This value is more near 100, and it is good more to be judged as mouldability.The results are summarized in the table 1.

＜about homogeneity 〉

Inhomogeneity mensuration is undertaken by following method: get the sample of 9 measuring points on the Width of the optical sheet that obtains, by SEM photography mensuration lenticular spacing separately, measure the ratio of minimum/maximum.For example, be 99.2 microns because the minimum lenticular spacing of the optical sheet that obtains by embodiment 1 is 98.0 microns, maximum lenticular spacing, therefore, (homogeneity)=(98.0/99.2) * 100=99 (%).This value is more near 100, and it is good more to be judged as mouldability.The results are summarized in the table 1.

＜about thickness and precision 〉

Determination of thickness is undertaken by following method: about TD (the Transverse Direction: transverse axis: direction Width) of the optical sheet raw sheet that obtains, use milscale to measure the thickness that amounts to 5 places of center, the left and right sides, center 25cm and the left and right sides, center 50cm, obtain the poor of maximum ga(u)ge and minimum thickness, with the average thickness value of this difference divided by 5 places.For example, be 1.19cm because the difference of the maximum ga(u)ge of the optical sheet that obtains by embodiment 1 and minimum thickness is the average thickness value at 0.03mm, 5 places, therefore, (thickness and precision)=(0.03/1.19) * 100=2.5 (%).This value is more little, and it is good more to be judged as thickness and precision.The results are summarized in the table 1.

＜about warpage 〉

The sheet of the 1000mm * 1000mm that will cut out from the optical sheet raw sheet that obtains is placed on and is arranged on temperature is that 23 ℃, humidity are 60% indoor platform after last 1 hour, under the state of horizontal positioned, utilizes gauge to measure gap (warpage) with platform.Warpage is that the situation note of not enough 2mm does zero, and warpage is that 2mm situation note above and not enough 3mm is made △, warpage be the above situation note of 3mm do *.

＜about optical property 〉

The following method of optical property utilization is measured.Taking-up is installed in the back of the body illuminator part on the slim liquid crystal TV set (WOOO UT-32-HV700) of (strain) Hitachi system, the light source of using as brightness measuring.(the rib line direction of the roughly oval rib shape of ※ lens is the direction parallel with the length direction of sheet to each optical sheet that obtains by preparation example and comparative preparation example with the size cutting that can insert described light source; That is, the cold-cathode tube and the direction of the rib line parallel of oval rib shape lens roughly of back of the body illuminator), lens face is installed on the back of the body illuminator in the mode of backlight.And, the prismatic lens (UTE-30 of 32 inches of a slices is set on diffuser plate in the mode of all equal backlight of lens face; MN Tech society system), a slice micro-lens sheet (UTE-21; MN Tech society system).

Then, light cold-cathode tube, about first: brightness directly over the cold-cathode tube and second: the brightness between cold-cathode tube and the cold-cathode tube, use and open up general Kanggong department (ト プ コ Application) and make chroma-luminance meter (BM-7) and measure.With the temperature of atmosphere is that 25 ℃, humidity are 60%RH, to measure distance be to be 0.2 ° and to implement apart from cold-cathode tube 50cm (with respect to the distance of the normal direction of back of the body illuminator face), visible angle.In addition, brightness and luminance deviation calculate by following formula.The results are summarized in the table 1.

Brightness=(first+second)/2

Luminance deviation (%)=| first-second | * 100/ brightness

Industrial applicibility

According to the present invention, can effectively prepare the optical sheet with surface configuration of giving full play to original design performance. In addition, the optical sheet of the present invention of preparation because moulding and the optical design on roller surface similarly are transferred, therefore, has been given play to the good performance as optical sheet like this. In addition, used the light source cell of this optical sheet, display unit also to bring into play good performance.

Description of reference numerals

1: punch die

2: the first rollers

3: second roller

4: the three rollers (surface forming roller)

5a: take up roll a

5b: take up roll b

6: carry-over pinch rolls

Claims (according to the modification of the 19th of treaty)

1. the preparation method of an optical sheet, it is characterized in that, make the optical element of rib shape roughly carry out among the preparation method of optical sheet of surface forming using at format roll with the coiling direction almost parallel ground moulding of sheet through surface working, above-mentioned format roll is set to the 3rd roller, be Va in the peripheral speed with this format roll, be the peripheral speed of draw roll when being Vb with take up roll, peripheral speed Vb is the 103-130% of peripheral speed Va.

2. the preparation method of optical sheet according to claim 1, wherein, optical element for ground moulding of coiling direction almost parallel and xsect be the optical element that the peak portion of convex or convex arc shaped and paddy portion that xsect is concavity or concave arc shape alternately are arranged in the roughly rib shape of ordered series of numbers almost parallel.

3. the preparation method of optical sheet according to claim 2, wherein, roughly the interval of the peak portion of the optical element of rib shape and peak portion or paddy portion and paddy portion is spaced apart below the 200 μ m.

4. an optical sheet is characterized in that, this optical sheet is to use that any described preparation method makes among the claim 1-3.

5. a light source cell is characterized in that, this light source cell has used the described optical sheet of claim 4.

6. a display device is characterized in that, this display device has been used the described light source cell of claim 5.

7. the preparation method of optical sheet according to claim 1, wherein, first roller is a mirror roller, second roller is mirror roller, mat roll or knurling rolls.

8. the preparation method of optical sheet according to claim 1 wherein, is between the 3rd roller and the take up roll carry-over pinch rolls to be set at format roll.

9. the preparation method of optical sheet according to claim 1, wherein, when representing the glass temperature of the thermoplastic resin that uses with Tg, with format roll promptly the temperature of the 3rd roller be set at Tg+20 ℃ to Tg+60 ℃.

Illustrate or state (according to the modification of the 19th of treaty)

Modification statement according to the 19th (1) proposition of Patent Cooperation Treaty

In claim 1, clear and definite format roll is the 3rd roller.

In citing document 1, format roll is first roller (Fig. 2).In addition, do not put down in writing the relation of the peripheral speed of format roll and take up roll fully.

Stipulated the relation of the peripheral speed of the peripheral speed of format roll and draw roll in citing document 2, still, the format roll of citing document 2 is second roller (Fig. 1).

In the present invention, by being the 3rd roller, can give sheet with ratio of briquetting height and the uniform optical element of shape with format roll.Second roller is the situation of format roll, even carry out the adjusting of peripheral speed, ratio of briquetting and homogeneity do not reach high level (reference example 1 of table 1) yet.

In claim 7, the kind of clear and definite first roller and second roller.

In claim 8, the clear and definite configuration of carry-over pinch rolls.

In claim 9, the clear and definite preferred temperature of the 3rd roller.

Claims (6)

1. A kind of preparation method of optical sheet, it is characterized in that, make the format roll of optical element forming on sheet carry out among the preparation method of optical sheet of surface forming using through surface working, be Va in the peripheral speed with format roll, be the peripheral speed of draw roll when being Vb with take up roll, peripheral speed Vb is the 103-130% of peripheral speed Va.
2. The preparation method of optical sheet according to claim 1, wherein, optical element for ground moulding of coiling direction almost parallel and xsect be the optical element that the peak portion of convex or convex arc shaped and paddy portion that xsect is concavity or concave arc shape alternately are arranged in the roughly rib shape of ordered series of numbers almost parallel.
3. The preparation method of optical sheet according to claim 2, wherein, roughly the interval of the peak portion of the optical element of rib shape and peak portion or paddy portion and paddy portion is spaced apart below the 200 μ m.
4. A kind of optical sheet is characterized in that, this optical sheet is to use that among the claim 1-3 any described preparation method makes.
5. A kind of light source cell is characterized in that, this light source cell has used the described optical sheet of claim 4.
6. A kind of display device is characterized in that, this display device has been used the described light source cell of claim 5.

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