JP2009163150A - Method for producing optical sheet laminate, method for producing back light unit, optical sheet laminate and back light unit obtained by the production method, and optical sheet laminating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: a method for producing an optical sheet laminate and back light unit, where prism sheets in the coaxial direction are mechanically made orthogonal, are superimposed and are blanked, thus the infiltration of foreign matters to a space between the optical sheets is extremely reduced, so as to reduce bright spots, also, the opportunity of damaging the optical sheets is reduced, so as to improve the quality of the optical sheet laminate, further, the number of steps is reduced, and mass production is possible; an optical sheet laminate and back light unit obtained by the production methods; and an optical sheet laminating device. <P>SOLUTION: The production method comprises: a superimposing step where the masters of two prism sheets in which convex lenses are adjacently arranged to a monoaxial direction on the whole surface, and the axial directions are the same, and the master of at least one diffusion sheet diffusing light are respectively fed, and the masters are laminated; a joining step where the laminated masters are fixed; and a blanking step where a prescribed sheet shape is blanked from the laminated masters. In the superimposing step, the axial directions of the lenses of either prism sheet master and the other prism sheet master are made orthogonal and are superimposed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical sheet laminate and a method for producing a backlight unit, and an optical sheet laminate and a backlight unit obtained by the production method, and in particular, an optical sheet laminate used in a liquid crystal display device or the like. Method of manufacturing an optical sheet laminate that can be manufactured at low cost in a simpler process than before, a method of manufacturing a backlight unit using the optical sheet laminate, and an optical sheet laminate and back obtained by the manufacturing method Regarding the light unit.

  Liquid crystal displays (LCDs) are used in mobile phones, notebook computers, LCD monitors, liquid crystal televisions, and the like. A transmissive LCD requires a backlight, and an optical sheet for adjusting the backlight is incorporated in the backlight unit in order to improve display performance. Various types of sheets such as prismatic structured sheets and diffusion sheets are used as optical sheets to improve output luminance, illumination uniformity, and viewing angle.

  FIG. 10 is a perspective view showing a conventional liquid crystal display device 100. The liquid crystal display device 100 is provided with a backlight unit 150 on the back side of a transmissive liquid crystal panel 151.

  The backlight unit 150 includes a light source 152, a light guide plate 153, a reflection plate 154, and the optical sheet 110. The light source 152 is realized by, for example, a light emitting diode (LED). The backlight unit 150 is an edge light type illumination device, and a light source 152 is provided on one side surface portion of the light guide plate 153, a reflection plate 154 is provided on one main surface portion of the light guide plate 153, and the other main portion of the light guide plate 153 is provided. An optical sheet 110 is provided on the surface portion. The optical sheet 110 is configured by laminating a plurality of sheets 111a to 111d. For example, 111a and 111d are diffusion sheets, and 111b and 111c are prism sheets.

  In this optical sheet 110, illumination light emitted from the light source 152 is incident on the light guide plate 153 from one side surface, is emitted from the other main surface of the light guide plate 153, and is irradiated on the liquid crystal panel 151 through the optical sheet 110. . The optical sheet 110 diffuses and condenses the illumination light emitted from the other main surface of the light guide plate 153 so that it can be illuminated uniformly over the entire liquid crystal panel 151. It is configured to demonstrate.

  The optical sheets 110 are laminated one by one between the light guide plate 153 and the liquid crystal display panel 151, and there are some problems in handling and assembling several individual sheet pieces during manufacturing. Each optical sheet is easily scratched and has a protective cover, which needs to be removed during assembly, which takes time. In addition, the sheet may be damaged when the protective cover is removed. Furthermore, since a plurality of sheets are stacked one by one, it takes time, and there are more opportunities for foreign matter to enter between the sheets or damage to the sheets, thereby reducing the throughput and reducing the yield. Furthermore, with the recent increase in size and size of liquid crystal display devices, there is a demand for reduction of foreign substances adhering to various optical sheets.

  As a method for solving this, a laminate of light adjusting sheets (for example, Patent Document 1) in which at least two optical sheets are bonded with zero gap bonding at a zero gap bonding portion provided outside the display region, and further, It has been proposed to perform cleaning before and after punching (for example, Patent Document 2).

JP-T-2006-513352 JP 2007-155941 A

  However, in order to handle a sheet bundled at the time of assembly, it is necessary to restrain at least two points on opposite sides of the outer periphery of the sheet. If it is not restrained at two or more points on the opposite sides, there is a possibility that the sheet will be opened, foreign matter may enter between the sheets, the sheet surface may be exposed, and the sheet surface may be damaged. In addition, the suction with the suction pad is only the uppermost sheet and cannot be used.

  Further, when restrained by multiple points, a difference occurs in the amount of expansion due to heat and humidity of each laminated sheet, so that an expansion difference occurs in each sheet, and wrinkles occur in the sheet laminate. This has a problem in optical characteristics.

  Patent Document 2 proposes that all the optical sheets are conveyed in parallel and processed. Usually, since the axial directions of the lenses of the two prism sheets are orthogonal to each other, it is necessary to form the axial direction of the original lens of the prism sheet perpendicular to the longitudinal direction of the original fabric. However, since the axial direction of the lens of the prism sheet is normally manufactured in parallel with the longitudinal direction of the original fabric, it is very difficult to manufacture in the direction perpendicular to the longitudinal direction. Further, even if a prism sheet whose lens axial direction is perpendicular to the longitudinal direction of the original fabric can be manufactured, two types of original fabrics having different lens axial directions exist, and the number of management items increases.

  Furthermore, the blade contact sheet is not used in the punching process of Patent Document 1. In the case of punching, the blade of the punching die is usually made to penetrate the raw fabric and the blade contact sheet is half-cut. This reliably punches the product and protects the punching blade. Further, the blade contact sheet also has a role of supporting the product from below, and if it is conveyed after punching without the blade contact sheet, the product falls from the original fabric.

  Further, the cleaning method proposed in Patent Document 2 can clean only the uppermost surface of the sheet.

  In view of the above problems, the object of the present invention is to reduce the number of bright spots by greatly reducing the intrusion of foreign matter between optical sheets by punching after overlapping the prism sheets in the coaxial direction so as to be mechanically orthogonal to each other, and Optical sheet laminate and backlight unit manufacturing method capable of mass production by reducing the number of steps and improving the quality of the optical sheet laminate by reducing the chance of damage to the optical sheet, and the optical sheet obtained by the manufacturing method It is to provide a laminate and a backlight unit.

  In the present invention, a plurality of lenses formed in a uniaxial direction are adjacently arranged on the entire surface of one side, and the original sheet of two prism sheets having the same axial direction and at least one diffusion for diffusing light. A sheet stacking process for supplying and feeding the sheet originals, a joining process for fixing the stacked sheets, and punching from the stacked sheets into a predetermined optical sheet shape A method of manufacturing an optical sheet laminate having the steps of: superimposing the original sheet of one prism sheet and the original lens of the other prism sheet orthogonally with each other in the axial direction. It is the manufacturing method of the optical sheet laminated body characterized.

  Furthermore, the present invention is characterized in that in the joining step, at least two sheets of the original fabric are joined at a portion other than the region used as the optical sheet laminate.

  Further, in the present invention, a protective sheet is provided on the surfaces of the prism sheet and the optical sheet of the diffusion sheet, and the superposition process is a next process without removing the charge after peeling the protective sheet from the optical sheet. It is characterized by being conveyed to.

  Furthermore, the present invention provides a method in which, in the superimposing step, after the original sheet of one prism sheet is cut to a predetermined length, the original sheet of the other prism sheet and the axial direction of the prism are orthogonal to each other. It is characterized by superimposing antis.

  Furthermore, the present invention is characterized in that after the original sheet of the prism sheet cut out to a predetermined length is directly overlapped with the original sheet of the underlying optical sheet, a portion other than the region used as the optical sheet is welded. To do.

  Furthermore, the present invention is characterized in that it has a first cleaning step of cleaning the front and back surfaces of each optical sheet before being conveyed to the superimposing step.

  Furthermore, the present invention is characterized in that the punching step includes a second cleaning step of cleaning the front and back surfaces and side surfaces of the optical sheet laminate after punching.

  In the first or second cleaning step, the present invention further includes an adhesive roller that contacts the optical sheet laminate and removes foreign matter, and a transfer roller that contacts the adhesive roller and has a higher adhesive force than the adhesive roller. The cleaning means is used to remove foreign matter from the optical sheet laminate.

  Furthermore, the invention is characterized in that the prism sheet is a prism sheet of a convex lens.

  Further, the present invention is an apparatus for laminating optical sheets, in which a plurality of lenses formed in a uniaxial direction are adjacently arranged on the entire surface of one side, and an original sheet of two prism sheets having the same axial direction. This is an optical sheet laminating apparatus that superimposes the original sheet of one prism sheet and the original sheet of the other prism sheet so that the axial directions of the lenses are orthogonal to each other.

  Moreover, this invention is manufactured by the manufacturing method of one of said optical sheet laminated bodies, It is an optical sheet laminated body characterized by the above-mentioned.

  Furthermore, the present invention is characterized in that a diffusion sheet is superimposed on the upper and lower surfaces of two superimposed prism sheets.

  Further, the present invention is characterized in that the prism of one prism sheet abuts on the surface of the other prism sheet without the prism, and the diffusion sheet is superimposed on the surface of the one prism sheet without the prism.

  The present invention also includes a step of taking out the optical sheet laminate produced by the method for producing an optical sheet laminate, and inserting the optical sheet laminate into a subassembly comprising a frame, a light guide plate, and a reflective sheet, It is a manufacturing method of the backlight unit which consists of an assembly | attachment process of the optical sheet laminated body which affixes a double-sided adhesive sheet.

  Furthermore, the present invention is characterized in that the surface of the assembly is neutralized after the sheet assembling step.

  Further, the present invention is a backlight unit manufactured by the backlight manufacturing method.

  According to the present invention, the prism sheets in the coaxial direction are orthogonally stacked and then punched out, so that the entry of foreign matter between the optical sheets can be extremely reduced and the bright spots can be reduced. Thus, since the opportunity to damage an optical sheet can be reduced, the quality of an optical sheet laminated body can be improved. In addition, since manual superposition is eliminated and the process is performed mechanically, the number of processes is reduced, mass production is possible, and productivity can be improved. In addition, it is not necessary to manufacture two types of original fabrics having different axial directions, and the axial directions of the lenses can be made orthogonal by using the original fabrics of two prism sheets having the same axial direction. Management is not complicated.

  According to the present invention, since at least two sheets are joined at a portion other than the region used as the optical sheet laminate in the joining step, it is possible to prevent deviation of the sheet material being conveyed, and to convey the material. However, a plurality of processes can be combined. Moreover, since the difference in the thermal expansion of each sheet | seat can be absorbed by making a joining position into parts other than the area | region used as an optical sheet laminated body, it does not optically degrade into the optical sheet laminated body which is a product. In particular, if the sheet to be inserted perpendicularly is fixed to the lower raw material to be laminated, the influence of the bonding is minimized.

  According to the present invention, since the neutralizing means is not provided until the optical sheet raw material from which the protective sheet has been peeled is conveyed to the superimposing step, the protective sheet is peeled off, and the optical sheet is superposed in a peeled and charged state. As a result, the optical sheets are adsorbed to each other, and no gap is formed between the sheets, so that the chance of entering foreign matter can be reduced.

  According to the present invention, one prism sheet original fabric is cut into a predetermined length, and the other prism sheet original fabric and the axial direction of the prism are orthogonal to each other so that the original fabric, that is, the cut prism sheets are stacked. Therefore, the overlapping prism sheets are orthogonal to each other. Since one prism sheet perpendicular to the axial direction of the lens is cut and overlapped with the other sheet original, the overlapped original can be transferred to the next process as it is.

  According to the present invention, since welding is performed at a portion other than the region used as the optical sheet laminate, the welded prism sheet and the lower layer sheet can be handled integrally. Tension control is performed for each sheet, and when a plurality of sheets are stacked and welded together, the apparatus configuration and the like are easy to handle. In the optical sheet laminate of the present invention, the optical sheets are not joined to each other, so that even if there is a difference in expansion between the optical sheets, wrinkles or the like do not occur, and the optical characteristics do not change.

  According to the present invention, there is a first cleaning process for cleaning the front and back surfaces of all of the prism sheet original and the diffusion sheet original before entering the superposition process. It is possible to reduce the chance of foreign objects entering between.

  According to the present invention, since there is a second cleaning step for cleaning the front and back surfaces and the side surfaces of the optical sheet laminate after punching, the foreign matter generated during punching can be removed by cleaning after punching.

  According to the present invention, the second cleaning means comprises a transfer roller that is in contact with the adhesive roller and the adhesive roller and has a higher adhesive force than the adhesive roller, and removes foreign matter by bringing the adhesive roller into contact with the optical sheet laminate. Therefore, the foreign matter attached on the adhesive roller can be transferred to the transfer roller, and the adhesive roller having a clean surface can be brought into direct contact with the product. As a result, the foreign matter in the optical sheet laminate can be eliminated.

  According to the present invention, since the prism sheet is a prism sheet of a convex lens, the optical sheet laminate obtained from the prism sheet can be configured as a practically useful black light.

  According to the optical sheet laminating apparatus of the present invention, a plurality of lenses formed in a uniaxial direction are adjacently arranged on the entire surface of one side, and one of the original sheets of two prism sheets whose axial directions are the same direction. The prism sheet original and the other prism sheet original are overlapped with the axis of the lens being orthogonal to each other, so that intrusion of foreign matter between optical sheets can be greatly reduced and the bright spots can be reduced, resulting in damage to the optical sheet. Therefore, the quality of the optical sheet laminate can be improved. Moreover, the optical sheet laminated body in which the number of processes is reduced and mass production is possible can be manufactured.

  According to the present invention, since it is manufactured by the above-described optical sheet laminate manufacturing method, it is possible to reduce the bright spots by extremely reducing foreign matter adhering when manufacturing the optical sheet, and to improve the quality of the optical sheet laminate. Can be improved. In addition, the manual overlay process is eliminated, the number of processes is reduced, and mass production becomes possible.

  According to the present invention, since it is an optical sheet laminate in which a diffusion sheet is superposed on the top and bottom of two prism sheets whose lens axial directions are orthogonal to each other, a practically useful optical sheet laminate is obtained.

  According to the present invention, the prism of one prism sheet is in contact with the non-prism surface of the other prism sheet, and the diffusion sheet is superposed on the non-prism surface of the lower prism sheet. It becomes a practically useful optical sheet laminate.

  According to the manufacturing method of the backlight unit of the present invention, the step of taking out the optical sheet laminate manufactured by the above-described optical sheet laminate manufacturing method, and the optical sheet laminate from the frame, the light guide plate, and the reflection sheet It consists of an assembly process of an optical sheet laminate that is inserted into a semi-assembled product and a light-shielding double-sided pressure-sensitive adhesive sheet is affixed, so that the entry of foreign matter between optical sheets can be greatly reduced and the bright spot can be reduced. Since the chances of damage can be reduced, a backlight unit with improved optical sheet laminate quality can be manufactured, and the number of processes required for assembly of the backlight unit can be reduced, resulting in improved productivity. I can plan.

  According to the present invention, since static elimination is performed to neutralize the product surface after the sheet assembling step, it is possible to eliminate the charge of the backlight unit incorporating the stacked optical sheet stack without static elimination.

  Since the backlight unit of the present invention is manufactured by the above-described backlight unit manufacturing method, the intrusion of foreign matter between the optical sheets can be greatly reduced and the bright spots can be reduced, and the chance of damage to the optical sheet is reduced. Therefore, a backlight unit with improved quality of the optical sheet laminate can be manufactured, and the number of steps required for assembling the backlight unit can be reduced, so that productivity can be improved.

  A backlight unit manufacturing apparatus 10 using the optical sheet laminate of the present invention will be described with reference to FIG.

  FIG. 1 is a side view of the backlight unit manufacturing apparatus 10 according to the present invention, and also illustrates a process for manufacturing an optical sheet laminate in the apparatus. The process proceeds in the direction of the arrow in the figure. In this embodiment, an example of the configuration of four optical sheets is shown. There is no particular limitation on the number of sheets, and when adding or reducing optical sheets, it is only necessary to increase or decrease the original sheets to be stacked.

  The same number of raw fabrics 12a to 12d as the optical sheets of the optical sheet laminate 21 to be manufactured on the left side as viewed in FIG. 1 are prepared. Hereinafter, when each sheet original fabric 12a-12d is identified and explained individually, the first layer sheet original fabric 12a, the second layer sheet original fabric 12b, the third layer sheet original fabric 12c, and the fourth layer sheet original Each of them is referred to as an anti-12d, and when any one of unspecified is described, the subscripts a to d are omitted and the original sheet 12 is referred to. The first layer sheet 12a is an upper diffusion sheet, the second layer sheet 12b is an upper prism sheet, the third layer sheet 12c is a lower prism sheet, and the fourth sheet original 12d is a lower diffusion sheet. It is an original fabric for forming. Each sheet original fabric 12 is a belt-shaped original fabric, and is prepared as an original fabric roll 11 by being wound in a roll shape. Further, the blade contact sheet 13a is wound in a roll shape with a belt-like sheet and is prepared as a blade contact sheet roll 13b.

  The sheet original fabrics 12a to 11d and the blade contact sheet 13a drawn from the original fabric rolls 11a to 11d pass through the first cleaning means 14a to 14d, respectively, and the front and back surfaces thereof are cleaned (first cleaning step). . Although not shown here, a protective sheet for protecting the surface of the optical sheet, particularly the prism sheet, until it is used may be attached. In that case, the protective sheet is peeled off before each of the original sheets 12a to 12d passes through the first cleaning means 14a to 14d. When the protective sheet is peeled off, the original sheets 12a to 12d are peeled and charged. Here, by not providing a static elimination means, the adhesion between sheets due to charging can be increased, and the probability of foreign matter intrusion between sheets can be reduced.

  The backlight unit manufacturing apparatus 10 includes: a sheet supply unit that supplies a sheet sheet 12 from each sheet roll 11 and a blade sheet 13a from a blade sheet roll 13b; a sheet sheet 12d on the blade sheet 13a; A first ultrasonic welder 15 that superimposes the sheet original fabric 12c thereon and fixes the sheets, a second ultrasonic welder 16 that fixes the original sheet 12 and the blade contact sheet 13a, and each sheet. Punching means 17 for punching the optical sheet laminate 21 from the original fabric 12, second (planar) cleaning means 18 for cleaning the optical sheet laminate 21 and the upper surface of the punched residue 27 after passing the punching means 17, and the optical sheet laminate 21 and a take-out part 27 for separating the optical waste layer 21 and a grip for gripping the optical sheet laminate 21. The hand 22, the second (end face) cleaning means 24 for cleaning the side surface of the optical sheet laminate 21 taken out, the built-in portion 38 for incorporating the optical sheet laminate 21 into the sub assembly 25, and the gripping hand 22 take-out portion 19 , A moving mechanism 23 that moves between the cleaning means 24 and the built-in unit 25, a light-shielding double-sided pressure-sensitive adhesive sheet affixing unit 39 that affixes the light-shielding double-sided pressure-sensitive adhesive sheet 29, and a conveyor 30 that conveys the sub-Assy 25. The backlight unit 28 is completed by the device.

  Moreover, the static elimination bar 55 can be installed above the conveyor 30 of the backlight unit manufacturing apparatus 10. The neutralization bar 55 can neutralize the backlight unit 28 by spraying ions on the surface of the finished backlight unit 28. In particular, in the case where static elimination is not performed when the protective film is peeled off, the optical sheet laminate 21 is incorporated in the backlight unit 28 while being charged. Therefore, the completed backlight unit 28 is passed under the static elimination bar 55 to neutralize the surface.

  Since FIG. 1 is viewed from the side, the process of superimposing the original direction of one prism sheet and the original direction of the other prism sheet so as to be orthogonal to each other is not shown. The original fabric 12c flows from the roll 11c toward the rear side of the paper, and when viewed from the side, the prism sheets are superposed at a right angle.

  FIG. 2 is a cross-sectional view of an optical sheet laminate 21 according to an embodiment of the present invention. Hereinafter, a description will be given with reference to FIG.

  The first layer of the optical sheet laminate 21 is an upper diffusion sheet 32, the second layer is an upper prism sheet 33 of a convex lens, the third layer is a lower prism sheet 34 of a convex lens, and the fourth is a lower diffusion sheet 35. . The prism sheet may be a concave lens, but the adjacent array of convex lenses is a concave lens when shifted. A convex lens is preferable. The diffusion sheets 32 and 35 are sheets in which beads 32c and 35c are fixed to the surfaces of the base sheets 32b and 35b with binders 32a and 35a, and have predetermined light diffusion performance. Usually, the upper diffusion sheet 32 and the lower diffusion sheet 35 have different bead diameters (average particle diameter) and light diffusion performance. The diameter of beads, the amount used, etc. are used in the same manner as before.

  The prism sheets 33 and 34 are lens sheets in which prisms 33a and 34a, which are convex lenses formed in one axial direction on one surface of the base sheets 33b and 34b, are adjacently arranged on the entire surface. The ones used are listed. For example, the prisms 33a and 34a have a pitch of 24 μm, a concavo-convex height of 12 μm, and a convex vertex angle of 90 degrees. Here, the entire surface includes substantially the entire surface. The upper prism sheet 33 and the lower prism sheet 34 are orthogonal to each other in the axial direction of the prisms 33a and 34a. The prism sheet is manufactured by a conventional method. For example, the prism sheets 33 and 34 are formed by forming a resin layer (for example, a UV curable resin) on the base sheets 33b and 34b, winding the sheet around a rotating uneven roller, and continuously running the resin layer on the surface of the uneven roller. Are produced by transferring the unevenness of the resin and curing the resin layer (for example, by UV irradiation). Therefore, the second layer sheet original fabric 12b and the third layer sheet original fabric 12c are normally formed such that the projections and depressions of the prisms 33a and 34a are parallel to the longitudinal direction of the original fabric. It is advantageous in terms of process sheet management to prepare the same sheet as the original sheet.

  In FIG. 1, two third layer sheet originals 12c and a fourth layer sheet original 12d having lens axes in the same direction are prepared, and the conveying direction of the third layer sheet original 12c and the fourth layer sheet original are prepared. By making the conveyance direction of the opposite 12d orthogonal, the axial directions of the prism sheets 33 and 34 can be orthogonalized.

  FIG. 3 is a plan view of the prism sheet orthogonal insertion portion of the embodiment of the backlight unit manufacturing apparatus of the present invention, and is also a diagram illustrating a process of conveying the prism sheets 33 and 34 with the axial directions orthogonal to each other. . Hereinafter, a description will be given with reference to FIG.

  FIG. 3 shows a state in which the portion of the backlight unit manufacturing apparatus 10 where the third layer sheet original 12c is superimposed on the fourth layer sheet original 12d is viewed from above.

  The respective sheet original fabrics 13a and 12d are drawn out from the blade contact sheet roll 13b and the fourth layer sheet original fabric roll 11d, and are superposed after the front and back sides of the sheet original fabric are cleaned by the first cleaning means 14e and 14d. The conveying direction of the third layer sheet original fabric 12c is orthogonal to the conveying direction of the fourth layer sheet original fabric 12d and the blade contact sheet 13a, and is drawn out from the third layer sheet roll 11c and passes through the first cleaning means 14c. The third layer sheet raw 12c is cut in the width direction by the cutting blade 31 every predetermined length. The cut third layer sheet original piece 12c is mounted on the fourth sheet original piece 12d, and the first ultrasonic welder 15 welds the three sheets at a welding point 36. Thereby, the cut piece of the third layer sheet original fabric 12c is fixed on the fourth layer sheet original fabric 12d. Here, fixing between the sheets by ultrasonic welding is shown. However, if the position between the cut piece of the third layer sheet raw fabric 12c and the fourth layer sheet original fabric 12d is not shifted in the subsequent process, ultrasonic welding is performed. It is not limited and other methods, such as an adhesive agent, may be sufficient, and the welding point 31 is not limited to two points. Further, the welding point 36 is provided at a position that does not cover the portion 37 that becomes the optical sheet laminated body 21 cut out from the original sheet 12 by the punching unit 17. This is because the warp and distortion of the optical sheet laminate 21 are not generated. That is, when the optical sheet laminate 21 has a joint, warpage or distortion occurs in the optical sheet laminate 21 due to a difference in expansion or contraction of the sheet due to an environmental change such as temperature or humidity. If warpage or distortion occurs in the optical sheet laminate 21, the optical characteristics are also affected. Therefore, it is preferable that the optical sheet laminate 21 is not provided with a joint.

  After fixing the third layer sheet original piece 12c on the fourth layer sheet original sheet 12d, the second layer sheet original sheet 12b is further laminated thereon, and the first sheet original sheet 12a is laminated thereon, The sheet material 12 and the blade contact sheet 13 a are fixed by the ultrasonic welder 16.

  The sheet supply means for supplying each sheet original fabric 12 and blade contact sheet 13a has a back tension adjusting mechanism (not shown) for applying tension to each sheet original fabric 12 and blade contact sheet 13a. The contact sheet 13a is clamped by a pair of conveyance rollers (not shown), and the conveyance roller pair rotates to feed the sheet original fabric 12 and the blade application sheet 13a from the original fabric roll 11 blade application sheet roll 13b. The blade contact sheet 13a is conveyed in the longitudinal direction. Then, it is supplied to the first ultrasonic welder 15, the second ultrasonic welder 16, and the punching machine 17. Further, in the sheet supply portion of each sheet original fabric 12 and the blade contact sheet 13a, for example, foreign matter adhering to the front and back of each sheet original fabric 12 and the blade contact sheet 13a by being sandwiched by an adhesive roller having adhesiveness, for example. First cleaning means 14 for removal is provided.

  The ultrasonic welding units 15 and 16 have an ultrasonic horn attached to the tip thereof, and press the sheet original fabric 12 to apply ultrasonic waves, so that the pressed portion of the sheet original fabric 12 is ultrasonically bonded. The What is necessary is just to set the ultrasonic welding units 15 and 16 in the range in which the welding part 36 does not melt out. Here, welding between the sheets is performed by both of the ultrasonic welding units 15 and 16, but either one may be used as long as there is no problem in sheet conveyance.

  The punching unit 17 is a cutting machine that punches out the optical sheet laminate 21 having a desired shape from the laminated sheet material 12. As the punching means 17, a punching machine using a servo press is generally used. The punching means 17 is placed close to a cutting table on which a sheet original 12 on which punching dies such as a Thomson die or a pinnacle die are stacked, and the cutting edge of the punching die is a blade contact sheet 13a. Stop at the position where you bite into. Thereby, all the sheet | seat original fabrics 12 can be cut | disconnected, and the cutting edge of a punching type | mold does not hit a cutting stand. By interposing the blade contact sheet 13a, the life of the punching die can be extended, and the cut optical sheet laminate 21 can be conveyed while being placed.

  The cut optical sheet laminated body 21 is passed through the cleaning device 18 together with the punched residue 27 to remove foreign substances adhering to the surface (surface cleaning means in the second cleaning means). The cleaning device 18 is not particularly limited, but uses several pressure-sensitive adhesive rolls in which a plurality of belts are stretched in the conveyance width direction so as not to lift the outermost optical sheet of the punched optical sheet laminate 21. Is preferred.

  The punched residue 27 is collected by winding it around the punched-out residue roll 20. At this time, the means for collecting the punched residue 27 functions as a carry-out means for the optical sheet laminate 21. That is, the punching waste 27 is wound around the punching roll 20 through the take-out portion 19 formed of a knife edge. When the extraction residue 27 passes through the extraction part 19, the optical sheet laminate 21 separated from the extraction residue 27 is separated and tends to advance in the transport direction up to that time due to its rigidity. The optical sheet laminate 21 is completely separated from the punched residue 27 by being gripped by the gripping hand 22 waiting at the place.

The second cleaning means also has an end face cleaning means 24.
The end surface cleaning unit 24 cleans the side surface of the optical sheet laminate 21 with respect to the optical sheet laminate 21 gripped by the gripping hand 22.

  FIG. 4 is a perspective view illustrating an end surface cleaning unit that cleans the side surface of the optical sheet laminate of the present invention. An adhesive roller 50 is disposed on the outer periphery of the optical sheet laminate 21. The adhesive roller 50 may be a drive roller to which a drive device (not shown) is attached, or may be a freely rotatable roller to which no drive device is attached. It contacts the side surface of the optical sheet laminate 21 and cleans it to remove foreign matter.

The first and second cleaning means can also be realized by the configuration of FIG.
FIG. 5 is a side view illustrating a front and back surface cleaning unit that cleans the front and back surfaces of the optical sheet laminate of the present invention. This figure will be described below. The adhesive sheet 57 and the transfer roller 56 are opposed to the front and back surfaces of the optical sheet laminate 21 so as to sandwich the optical sheet laminate 21. One of the optical sheet laminates 21 is gripped by a gripping hand 58, the optical sheet laminate 21 is sandwiched between the adhesive rollers 57, and then the adhesive roller 57 is moved in the direction of the arrow in the figure, thereby The foreign matter adhering to the front and back surfaces is removed by the adhesive roller 57, and the removed foreign matter adhering to the adhesive roller 57 is transferred to the transfer roller 56. At this time, the adhesive force of the transfer roller 56 is set higher than that of the adhesive roller 57, and the adhesive roller 57 is always pressed against the optical sheet laminate 21 with no foreign matter on the surface. The adhesive roller 57 may be a drive roller to which a drive device (not shown) is attached, or may be a freely rotatable roller to which no drive device is attached.

  In this way, the front and back surfaces of the optical sheet laminate 21 are cleaned to remove foreign matters. In FIG. 5, the optical sheet laminate 21 has been described as an object to be cleaned, but there is no problem even if it is the original sheets 12 a to 11 d.

  The materials of the adhesive roller 50 and 57 transfer roller 56 described with reference to FIGS. 4 and 5 are not particularly limited, but silicon rubber, butyl rubber, or the like is preferable as the cleaning roller for the optical member. The cleaning means is not limited, and for example, a vacuum device, a static electricity removing device, or the like can be used.

  6 and 7 are diagrams showing the structure of the backlight unit. 6 is an exploded perspective view, and FIG. 7 is a cross-sectional view of the backlight unit in the short side direction (a) and the long side direction (b). Hereinafter, the structure of the backlight unit will be described with reference to FIGS. 6 and 7.

  The backlight unit 26 has a laminated optical sheet 21 mounted on a sub assembly 25 and is fixed by a light-shielding double-sided adhesive sheet 29. The sub assembly 25 is a frame 40 in which a light guide plate 42, a reflection sheet 43, and an FPC 44 to which an LED 45 is attached are incorporated.

  The optical sheet laminate 21 whose side surfaces have been cleaned by the end surface cleaning means 24 is conveyed to the assembly unit 25 by the gripping hand 22 and incorporated into the sub assembly 25.

  The sub assembly 25 in which the optical sheet laminate 21 is incorporated is transported to the light-shielding double-sided pressure-sensitive adhesive sheet pasting section 26 by the transport conveyor 30. In the light-shielding double-sided pressure-sensitive adhesive sheet affixing unit 26, the hand part holding the light-shielding double-sided pressure-sensitive adhesive sheet 29 is pasted by pressing the light-shielding double-sided pressure-sensitive adhesive sheet 29 against the sub assembly 25. Thus, the backlight unit 28 is completed.

  FIG. 8 is a plan view of an orthogonal insertion portion of a prism sheet according to another embodiment of the present invention, and is a diagram of another form of the optical sheet laminating apparatus. This embodiment is an example in which the third sheet original fabric 12c is pulled out from the roll 11c in parallel with the direction in which the other sheet original fabrics 12a, 12b, 12d are pulled out, except for the orthogonal sheet insertion portions.

  A predetermined amount from the roll 11c is pulled out and cut by the cutting blade 31, the original raw sheet piece 12e is held by the sheet holding hand 48, and the original sheet piece 12e is rotated by 90 ° by the sheet loading robot 49. It is mounted on the 4-layer sheet original fabric 12d. The loaded original sheet piece 12e is fixed by the fourth layer sheet original sheet 12d, the blade contact sheet 13b, and the welding portion 36.

  FIG. 9 is a cross-sectional view illustrating the configuration of another optical sheet laminate 51. Hereinafter, a description will be given with reference to FIG.

  The first layer of the optical sheet laminate 51 includes an upper prism sheet 52, the second layer includes a lower prism sheet 53, and the third layer includes a lower diffusion sheet 54.

  The upper prism sheet 52 is provided with a prism 52a on one surface of a base sheet 52b and a diffusion layer 52c on the opposite side. The upper prism sheet 52 and the lower prism sheet 53 are orthogonal to each other in the axial direction of the prism.

  Such a three-layer structure can be dealt with only by reducing the number of original sheets to be stacked with the prism sheets orthogonally crossed.

  As described above, the embodiments of the optical sheet laminate and the backlight unit and the manufacturing method thereof according to the present invention have been described, but the present invention is not limited to the examples of the above embodiments, and various aspects can be taken. For example, in the example of this embodiment, the prisms of the lower prism sheet 33 and the upper prism sheet 34 are facing upward in any case, but the prisms can be stacked with the prisms facing downward. Further, the layer configuration of the optical sheet laminate is not limited to the example of the embodiment, and for example, protective sheets can be laminated on the upper and lower surfaces. Even if it is the above structures, it acts similarly to this embodiment and the same effect is acquired.

It is a side view of the backlight unit manufacturing apparatus of this invention. It is sectional drawing of the optical sheet laminated body which is one Embodiment of this invention. It is a top view of the orthogonal insertion part of the prism sheet of one Embodiment in the backlight unit manufacturing apparatus of this invention. It is a perspective view explaining the end surface cleaning part which cleans the optical sheet laminated body side surface of this invention. It is a side view explaining the front and back cleaning part which cleans the front and back of the optical sheet laminated body of this invention. It is a disassembled perspective view of the backlight unit of the present invention. It is sectional drawing of the short side direction (a) and the long side direction (b) of the backlight unit of this invention. It is a top view of the orthogonal insertion part of the prism sheet of another embodiment of this invention. It is sectional drawing of the optical sheet laminated body which is another embodiment of this invention. It is a perspective view which shows the liquid crystal display device 100 of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Backlight unit manufacturing apparatus 11 Original fabric roll 11a 1st layer original fabric roll 11b 2nd layer original fabric roll 11c 3rd layer original fabric roll 11d 4th layer original fabric roll 12 Original fabric 12a 1st layer original fabric 12b 2nd Layer original fabric 12c third layer original fabric 12d fourth layer original fabric 12e raw fabric sheet piece 13a blade contact sheet 13b blade contact sheet roll 14 original fabric cleaning means 14a first layer original fabric first cleaning means 14b second layer original Anti-first cleaning means 14c First-layer cleaning means for the third layer original fabric 14d First-cleaning means for the fourth-layer original fabric 14e Blade contact sheet cleaning means 15, 16 Ultrasonic welder 17 Punching means 18 Surface cleaning means 19 Optical Sheet laminated body takeout part 20 Unwinding take-up roll 21, 51 Optical sheet laminated body 22 Sheet gripping c De 23 sheet transfer unit 24 end surface cleaning unit 25 sub Assy
26, 28, 150 Backlight unit 27 Drainage 29 Light-shielding double-sided adhesive sheet 30 Conveyor 31 Cutting blade 32 Upper diffusion sheet 33, 52 Upper prism sheet 34, 53 Lower prism sheet 35, 54 Lower diffusion sheet 36 Welding part 37 Punching part 38 Sheet mounting portion 39 Light-shielding double-sided adhesive pasting portion 40 Frame 42 Light guide plate 43 Reflective sheet 44 FPC
45 LED
48 Sheet gripping hand 49 Sheet mounting robot 50 Adhesive roller 55 Static elimination bar 56a, 56b Transfer roller 57a, 57b Adhesive roller 58a, 58b Grasp hand 100 Conventional liquid crystal display device 110 Optical sheet 111a, 111d Diffusion sheet 111b, 111c Prism sheet 151 Liquid crystal Panel 152 Light source 153 Light guide plate 154 Reflector

Claims (16)

A plurality of lenses formed in a uniaxial direction are adjacently arranged on the entire surface of one side, and an original fabric of two prism sheets having the same axial direction and an original fabric of at least one diffusion sheet that diffuses light. And a stacking step of laminating these raw materials by supplying each of
A bonding process for fixing the laminated raw materials,
A punching process for punching the laminated original fabric into a predetermined optical sheet shape;
A method for producing an optical sheet laminate comprising:
A method for producing an optical sheet laminate, wherein in the superimposing step, the axial directions of the lenses of one prism sheet and the other prism sheet are orthogonal to each other.   The method for producing an optical sheet laminate according to claim 1, wherein, in the joining step, at least two sheets of the original fabric are joined at a portion other than a region used as the optical sheet laminate.   A protective sheet is provided on the surface of the optical sheet of the prism sheet and the diffusion sheet, and after the protective sheet is peeled off from the optical sheet, it is conveyed to the superimposing process which is the next process without discharging. The manufacturing method of the optical sheet laminated body of Claim 1 or 2 characterized by the above-mentioned.   In the superimposing step, after the original sheet of one prism sheet is cut into a predetermined length, the original sheet of the other prism sheet and the axial direction of the prism are overlapped so that the original sheet is overlapped. The manufacturing method of the optical sheet laminated body as described in any one of Claims 1-3.   The method for producing an optical sheet laminate according to any one of claims 2 to 4, wherein the joining is welding.   The optical sheet laminate production according to any one of claims 1 to 5, further comprising a first cleaning step of cleaning the front and back surfaces of each optical sheet before being conveyed to the superimposing step. Method.   The optical sheet laminate according to any one of claims 1 to 6, further comprising a second cleaning step of cleaning the front and back surfaces and side surfaces of the optical sheet laminate after punching in the punching step. Manufacturing method.   In the first or second cleaning step, an adhesive roller that contacts the optical sheet laminated body to remove foreign matter and a cleaning unit that is in contact with the adhesive roller and has a transfer roller having higher adhesive strength than the adhesive roller are used. The foreign material of an optical sheet laminated body is removed, The manufacturing method of the optical sheet laminated body of Claim 6 or 7 characterized by the above-mentioned.   The method for producing an optical sheet laminate according to any one of claims 1 to 8, wherein the prism sheet is a prism sheet of a convex lens.   A device for laminating optical sheets, in which a plurality of lenses formed in a uniaxial direction are adjacently arranged on the entire surface of one side, and one prism of a raw material of two prism sheets having the same axial direction An optical sheet laminating apparatus that superimposes the original sheet of the sheet and the other prism sheet by making the axial directions of the lenses orthogonal to each other.   An optical sheet laminate produced by the method for producing an optical sheet laminate according to any one of claims 1 to 9.   12. The optical sheet laminate according to claim 11, wherein a diffusion sheet is superimposed on two upper and lower surfaces of two superimposed prism sheets.   12. The optical sheet laminate according to claim 11, wherein the prism of one prism sheet abuts on the surface of the other prism sheet without the prism, and the diffusion sheet is superposed on the surface of the one prism sheet without the prism. . An extraction step of taking out the optical sheet laminate produced by the method for producing an optical sheet laminate according to any one of claims 1 to 9,
A method for manufacturing a backlight unit comprising a step of assembling an optical sheet laminate in which the optical sheet laminate is inserted into a semi-assembly comprising a frame, a light guide plate, and a reflection sheet, and a light-shielding double-sided adhesive sheet is attached.   15. The method for manufacturing a backlight unit according to claim 14, wherein the surface of the assembly is neutralized after the sheet assembling step.   A backlight unit manufactured by the method for manufacturing a backlight unit according to claim 14 or 15.

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