WO2013180009A1

WO2013180009A1 - Optical sheet manufacturing method, optical sheet processing device, and optical sheet processing method

Info

Publication number: WO2013180009A1
Application number: PCT/JP2013/064373
Authority: WO
Inventors: 尚規奥; 英則角谷; 規光坂田; 武志川上; 顕谷河; 則希川端
Original assignee: 住友化学株式会社
Priority date: 2012-05-29
Filing date: 2013-05-23
Publication date: 2013-12-05
Also published as: TW201402309A

Abstract

This optical sheet manufacturing method is an optical sheet manufacturing method for manufacturing an optical sheet (107) produced from thermoplastic resin and having a light incident end surface (107a) in which recessed and protruding portions are provided, the method comprising: a preparation step for preparing a transfer mold (124) having a transfer surface (125a) for imparting the recessed and protruding portions to the light incident end surface (107a) of the optical sheet (107); and a processing step for forming the recessed and protruding portions on the light incident end surface (107a) by pressing the transfer surface (125a) and the light incident end surface (107a) against each other while heating the transfer mold (124). According to the present invention, chips can be prevented from being mixed into and adhering to the optical sheet, thereby making it possible to stabilize the quality of the optical sheet and enhance yield.

Description

Optical sheet manufacturing method, optical sheet processing apparatus, and optical sheet processing method

The present invention relates to an optical sheet manufacturing method for manufacturing an optical sheet having an uneven portion on a light incident end surface, and an optical sheet processing apparatus and method for forming an uneven portion on a light incident end surface of an optical sheet.

An example of the optical sheet is a light guide plate used in a backlight unit of a liquid crystal display device. In the edge-light type backlight unit, a plurality of light sources are arranged in an array facing the light incident end face of the light guide plate, and light incident from the light incident end face of the light guide plate is emitted from the light exit surface, thereby liquid crystal Illuminate the display panel. However, in the edge light type backlight unit, luminance unevenness occurs in the illumination light emitted from the vicinity of the light incident end surface of the light exit surface of the light guide plate.

Therefore, in order to solve such a problem, for example, as described in Patent Document 1, a technique is known in which a cut and polished surface is formed on a light incident end surface of a light guide plate. The cutting and polishing surface described in Patent Document 1 is a rough surface having a large number of fine vertical irregularities extending in a direction perpendicular to the light emitting surface of the light guide plate.

JP 2010-182478 A

However, in the above-described prior art, cutting and polishing surfaces are formed on the light incident end surface of the light guide plate by machining using a machine tool such as a milling machine, NC router, or planar, and thus cutting chips are generated by cutting. . For this reason, cutting powder mixes and adheres to the light guide plate, resulting in poor quality. Further, from the viewpoint of productivity and the like, it is desired to shorten the processing time of the uneven portion with respect to the light incident end face of the light guide plate.

An object of the present invention is to provide an optical sheet manufacturing method, an optical sheet processing apparatus, and an optical sheet processing method capable of preventing mixing and adhesion of chips to the optical sheet. Another object of the present invention is to provide an optical sheet manufacturing method capable of processing a concavo-convex portion in a short time with respect to a light incident end face of an optical sheet without generating chips.

The present invention is an optical sheet manufacturing method for manufacturing an optical sheet made of a thermoplastic resin and having an uneven portion on the light incident end surface, and has a transfer surface for providing the uneven portion on the light incident end surface of the optical sheet. It includes a preparation step of preparing a transfer mold and a processing step of forming an uneven portion on the light incident end surface by pressing the transfer surface and the light incident end surface with the transfer mold heated. Is.

In such an optical sheet manufacturing method of the present invention, the transfer surface of the transfer mold and the optical sheet are heated while the transfer mold having the transfer surface for imparting the uneven portion to the light incident end surface of the optical sheet is heated. Unlike the case where the uneven portions are formed by cutting by forming the uneven portions on the light incident end surfaces of the optical sheet by pressing the light incident end surfaces to each other, chips are not generated. Thereby, mixing and adhesion of swarf to the optical sheet can be prevented. Further, when the uneven portion is formed by cutting, the processing time tends to be long. However, in the present invention using the transfer mold, the heating temperature of the transfer mold, the transfer surface of the transfer mold, and the optical sheet By adjusting the pressing pressure between the end faces, the processing time can be shortened.

In the processing step, the transfer mold may be heated to a temperature that is equal to or higher than the Vicat softening temperature of the thermoplastic resin and equal to or lower than the Vicat softening temperature of the thermoplastic resin + 50 ° C. By setting the heating temperature of the transfer mold to be equal to or higher than the Vicat softening temperature of the thermoplastic resin, the thermoplastic resin is moderately softened, so that the optical sheet is prevented from cracking and an uneven portion is formed on the light incident end face of the optical sheet. It can transfer well. In addition, by setting the heating temperature of the transfer mold to the Vicat softening temperature of the thermoplastic resin + 50 ° C. or less, the melt flow of the thermoplastic resin is prevented, so the elastic modulus of the thermoplastic resin is lowered and the optical sheet is deformed. And the transfer mold is hardly contaminated.

In addition, the transfer mold has a metal roll part, and the peripheral surface of the roll part is a transfer surface. In the processing step, the transfer part and the light incident end face are pressed against each other and the roll part is rotated. In addition, the roll portion may be moved relative to the optical sheet along the light incident end surface of the optical sheet to form an uneven portion on the light incident end surface. In this case, when the transfer surface of the transfer mold (the peripheral surface of the roll part) and the light incident end surfaces of the optical sheet are pressed against each other, they are not in surface contact but in line contact. The pressure can be reduced.

Further, the transfer surface is provided with a convex or concave portion for transfer having a prism shape or a lenticular shape, the pitch of the concave and convex portions for transfer is 10 μm to 500 μm, and the height of the concave and convex portions for transfer is 10 μm to 300 μm. Also good. By making the shape of the concavo-convex portion for transfer into a prism shape or a lenticular shape, a transfer surface having the concavo-convex portion for transfer can be made relatively easily. Also, by setting the pitch of the uneven portion for transfer to 10 μm to 500 μm and the height of the uneven portion for transfer to 10 μm to 300 μm in accordance with this, the uneven portion is transferred to the light incident end face of the optical sheet at a desired transfer rate. can do.

In the processing step, the transfer surface and the light incident end surface may be pressed together with a pressure of 0.05 MPa to 50 MPa. By setting the pressing pressure to 0.05 MPa or more, the concavo-convex portion can be satisfactorily transferred to the light incident end face of the optical sheet. Moreover, the crack of an optical sheet can be prevented by making pressing pressure into 50 Mpa or less.

Further, as the thermoplastic resin, an amorphous resin having high dimensional accuracy, impact strength, and transparency may be used.

In the processing step, the transfer mold and the optical sheet may be released before the transfer surface is completely filled with the thermoplastic resin.

In this case, by pressing the transfer mold of the transfer mold and the light incident end faces of the optical sheet in a state where the transfer mold having the transfer surface for imparting the uneven portion to the light incident end face of the optical sheet is heated, By forming the uneven portion on the light incident end surface of the sheet, unlike the case of forming the uneven portion by cutting, it is not necessary to generate chips.

In addition, when forming an uneven portion on the light incident end surface of the optical sheet, by releasing the transfer mold and the optical sheet before the transfer surface of the transfer mold is completely filled with the thermoplastic resin, The uneven part can be processed in a short time. At this time, since the transfer mold and the optical sheet are released before the transfer surface of the transfer mold is completely filled with the thermoplastic resin, the tip of the concavo-convex portion becomes a flat surface or a surface that is almost flat. . Here, the nearly flat surface means that, for example, when the uneven portion for transfer having a prism shape is transferred to the light incident end surface of the optical sheet, the inclination is clearly smooth compared to the concave oblique side of the uneven portion. It refers to the surface of the level. That is, the concavo-convex portion has a shape in which a flat region (including a region close to flat) and a concave region are mixed. Accordingly, the optical characteristics (light diffusibility) of the optical sheet are improved, and the tip of the concavo-convex portion is prevented from being chipped.

In the processing step, the transfer mold may be heated to a temperature that is equal to or higher than the Vicat softening temperature of the thermoplastic resin and equal to or lower than the Vicat softening temperature of the thermoplastic resin + 40 ° C. By setting the heating temperature of the transfer mold to be equal to or higher than the Vicat softening temperature of the thermoplastic resin, the thermoplastic resin is moderately softened, so that the optical sheet is prevented from cracking and an uneven portion is formed on the light incident end face of the optical sheet. It can transfer well. In addition, by setting the heating temperature of the transfer mold to the Vicat softening temperature of the thermoplastic resin + 40 ° C. or lower, the melt flow of the thermoplastic resin is prevented, so that the elastic modulus of the thermoplastic resin is lowered and the optical sheet is deformed. And the transfer mold is hardly contaminated.

Also, the transfer surface is provided with a transfer uneven portion having a prism shape or a lenticular shape, and in the processing step, the length F of the base flat region and the length of the convex region at one pitch of the transfer uneven portion. When the ratio F / Wa to Wa is 0 to 50%, the ratio F ′ / Wa ′ of the length F ′ of the tip flat region and the length Wa ′ of the concave region at one pitch of the concavo-convex portion is 10 A concavo-convex portion may be formed on the light incident end face so as to be ˜300%. Here, the base flat region and the tip flat region include not only a completely flat region but also a region close to flat. By adjusting the heating temperature of the transfer mold, the pressing pressure and the pressing time between the transfer surface of the transfer mold and the light incident end surface of the optical sheet, the length of the flat region at the tip of the uneven portion is set to a desired value. be able to.

The present invention also provides an optical sheet processing apparatus for forming an uneven portion on a light incident end surface of an optical sheet made of a thermoplastic resin, the stage supporting the optical sheet, and the light incident end surface of the optical sheet supported by the stage. A transfer mold having a transfer surface for providing an uneven portion, a heating means for heating the transfer mold, a pressure applying means for applying pressure so as to press the transfer surface and the light incident end surfaces, and a light incident end surface And a driving means for driving at least one of a stage and a transfer mold so as to form an uneven portion.

By using such an optical sheet processing apparatus of the present invention, the above-described optical sheet manufacturing method can be carried out. As a result, chips are not generated as described above, and therefore, mixing and adhesion of chips to the optical sheet can be prevented. Further, as described above, the processing time can be shortened.

The transfer mold has a metal roll part, and the peripheral surface of the roll part is a transfer surface. The driving means is a means for rotating the roll part and a roll part along the light incident end face of the optical sheet. There may be a means for moving the relative to the stage. In this case, when the transfer surface of the transfer mold and the light incident end surfaces of the optical sheet are pressed against each other, both are in a line contact state, so that the pressing pressure can be reduced.

The optical sheet processing apparatus may further include a clamping unit that clamps the optical sheet with respect to the stage. In this case, in a state where the optical sheet is clamped with respect to the stage by the clamping means, the pressure applied by the pressure applying means does not escape upward, so that the transfer surface of the transfer mold and the incident light of the optical sheet The end faces can be effectively pressed against each other.

Moreover, this invention is an optical sheet processing apparatus which forms an uneven part in the light-incidence end surface of the optical sheet which consists of thermoplastic resins in another side surface, Comprising: For giving an uneven part to the light-incidence end surface of an optical sheet A metal transfer roll having a transfer surface, a pair of stages arranged to sandwich the transfer roll and supporting the optical sheet, a heating means for heating the transfer roll, and the transfer surface and the light incident end surface are pressed against each other. And a pressure applying means for applying pressure to the stage, a rotating means for rotating the transfer roll, and a moving means for moving the stage in the direction of forming the concavo-convex portion with respect to the transfer roll.

Using such an optical sheet processing apparatus of the present invention, when forming a concavo-convex portion on the light incident end surface of an optical sheet made of a thermoplastic resin, the metal transfer roll is heated and the transfer surface of the transfer roll and While the pressure is applied to the stage so that the light incident end faces of the optical sheet are pressed against each other, the optical sheet is made incident by moving the stage in the direction of forming the concavo-convex part with respect to the transfer roll while rotating the transfer roll. An uneven portion is provided on the end face. Thereby, unlike the case where an uneven | corrugated | grooved part is formed by cutting, since a swarf does not generate | occur | produce, the mixing and adhesion of the swarf to an optical sheet can be prevented.

Further, by arranging a pair of stages that support the optical sheet so as to sandwich the transfer roll, it is possible to form an uneven portion on the light incident end face of the optical sheet on both sides of the transfer roll. Specifically, the optical sheet supported by the other stage is not formed during the period in which the concave and convex portions are formed on the light incident end face of the optical sheet supported by one stage (for example, the period during which the optical sheet is inserted or removed). An uneven portion can be formed on the light incident end face. In this case, it is not necessary to interrupt the process of forming the concavo-convex portion on the light incident end face of the optical sheet for loading and unloading the optical sheet. Thereby, the processing tact of an optical sheet can be improved.

Here, the rotating means has a pair of motors provided corresponding to each stage, and a rotation power transmission mechanism for transmitting the driving force of each motor to the transfer roll, and the moving means is the above-mentioned pair of motors. And a moving power transmission mechanism for transmitting the driving force of each motor to each stage. In this case, since a pair of motors are shared as components of the rotating means and moving means, it is not necessary to separate the motor for rotating the transfer roll and the motor for moving each stage, and the number of motors to be used. Can be minimized.

At this time, the rotational power transmission mechanism includes a first spur gear attached to the roll shaft of the transfer roll, a pair of second spur gears that mesh with the first spur gear, and motors for the second spur gears. And a pair of clutches for intermittently transmitting and receiving the driving force of each, and a power transmission mechanism for movement is attached to each pair of racks provided on each stage and each motor output shaft, and each rack And a pair of pinions that mesh with each other. In this case, the rotation power transmission mechanism and the movement power transmission mechanism can be realized with a simple configuration.

Further, the present invention in this aspect is an optical sheet processing method for forming a concavo-convex portion on a light incident end surface of an optical sheet made of a thermoplastic resin, the preparation step for preparing the optical sheet processing apparatus described above, and a transfer roll. While heating, with the pressure applied to the stage so that the transfer surface and the light incident end surface are pressed together, the stage is moved in the direction of forming the concavo-convex part while rotating the transfer roll. Forming a concavo-convex portion on the light end face, and in the forming step, the concavo-convex portion is not formed on the light incident end face of the optical sheet supported by one of the pair of stages. An uneven portion is formed on the light incident end face of the optical sheet supported on the other side.

In such an optical sheet processing method of the present invention, the transfer roll is heated and the transfer roll is rotated in a state where pressure is applied to the stage so as to press the transfer face of the transfer roll and the light incident end faces of the optical sheet. Then, by moving the stage in the formation direction of the concavo-convex portion with respect to the transfer roll, the concavo-convex portion is imparted to the light incident end surface of the optical sheet. Thereby, unlike the case where an uneven | corrugated | grooved part is formed by cutting, since a swarf does not generate | occur | produce, the mixing and adhesion of the swarf to an optical sheet can be prevented.

In addition, the light incident end surface of the optical sheet supported by the other stage during a period in which the uneven portion is not formed on the light incident end surface of the optical sheet supported by one stage (for example, the period during which the optical sheet is inserted or removed) By forming the concavo-convex portion on the optical sheet, it is not necessary to interrupt the step of forming the concavo-convex portion on the light incident end surface of the optical sheet in order to load and unload the optical sheet. Thereby, the processing tact of an optical sheet can be improved.

In the molding process, while the optical sheet is taken out from one stage, the other stage is moved from one side to the other side, and an uneven portion is formed on the light incident end face of the optical sheet supported by the other stage. After performing the first step to be formed and the first step, while the optical sheet is being taken out from the other stage, one stage is moved from one side to the other side and supported by one stage. The second step of forming the uneven portion on the light incident end face of the optical sheet, and the second stage is moved from the other side to the one side while the optical sheet is taken out from the one stage after performing the second step. The third step of forming an uneven portion on the light incident end surface of the optical sheet supported by the other stage and the third step are performed, and then the optical sheet is taken out from the other stage. During the one stage is moved to one side from the other side may comprise a fourth step of forming an uneven portion to the light incident face of the optical sheet supported on one stage. In this case, the concave and convex portions can be formed on the light incident end face from both directions for both the optical sheet supported by one stage and the optical sheet supported by the other stage.

Further, in the molding process, while the optical sheet is being taken out from one stage, the other stage is moved from one side to the other, and the light incident end face of the optical sheet supported by the other stage is uneven. The first step for forming the part, the second step for moving the other stage from the other side to the one side, and the second step while one stage is waiting after the first step is performed After that, while taking out the optical sheet from the other stage, one stage is moved from the other side to one side to form an uneven portion on the light incident end face of the optical sheet supported by one stage. The third step may include a fourth step of moving one stage from one side to the other while the other stage is waiting after the third step is performed. In this case, since it is sufficient that one worker is provided on each of the one side and the other side of the optical sheet processing apparatus, the number of workers can be reduced.

Further, in the molding process, while the optical sheet is being taken out from one stage, the other stage is moved from one side to the other, and the light incident end face of the optical sheet supported by the other stage is uneven. The first step for forming the part, the second step for moving the other stage from the other side to the one side, and the second step while one stage is waiting after the first step is performed After that, while taking out the optical sheet from the other stage, one stage is moved from one side to the other to form a concavo-convex portion on the light incident end surface of the optical sheet supported by one stage. And a fourth step of moving one stage from the other side to the one side while the other stage is waiting after the third step is performed. In this case, since it is sufficient that there are two workers on one side of the optical sheet processing apparatus, the number of workers can be reduced. Also, even if it is difficult for a worker to work on the other side of the optical sheet processing apparatus because there is a wall or the like on the other side of the optical sheet processing apparatus, the work can be performed without trouble on one side of the optical sheet processing apparatus. It can be performed.

In another aspect, the present invention is an optical sheet processing apparatus for forming a concavo-convex portion on a light incident end surface of an optical sheet made of a thermoplastic resin, the stage supporting the optical sheet, and the optical supported by the stage. Metal transfer roll having a transfer surface for imparting irregularities to the light incident end face of the sheet, heating means for heating the transfer roll, and pressure application for applying pressure so as to press the transfer face and the light incident end face together Means, a rotating means for rotating the transfer roll, a first moving means for moving the stage relative to the transfer roll in the direction of forming the concavo-convex portion, and a transfer roll in the roll axis direction of the transfer roll with respect to the stage. And a second moving means for relatively moving.

Using such an optical sheet processing apparatus of the present invention, when forming a concavo-convex portion on the light incident end surface of an optical sheet made of a thermoplastic resin, the metal transfer roll is heated and the transfer surface of the transfer roll and With the pressure applied so that the light incident end faces of the optical sheet are pressed against each other, the stage is moved relative to the transfer roll in the direction of forming the concavo-convex part while rotating the transfer roll. An uneven portion is provided on the light end face. Thereby, unlike the case where an uneven | corrugated | grooved part is formed by cutting, since a swarf does not generate | occur | produce, the mixing and adhesion of the swarf to an optical sheet can be prevented.

Further, for example, when the transfer surface of the transfer roll is thermally transferred to the light incident end surface of the optical sheet, the thermoplastic resin that is the material of the optical sheet is thermally decomposed, and the additive contained in the thermoplastic resin is precipitated. It may adhere to the transfer surface of the transfer roll as dirt. When contamination occurs on the transfer surface of the transfer roll in this way, the transfer roll is placed on the stage so that the incident end surface of the optical sheet does not come into contact with the occurrence of contamination on the transfer surface of the transfer roll. Move relatively in the roll axis direction of the transfer roll. As a result, even if the transfer surface of the transfer roll becomes dirty, the formation of uneven portions on the light incident end surface of the optical sheet is continuously performed on the clean transfer surface of the transfer roll without cleaning the transfer surface. Can do.

A masking film may be bonded to the main surface of the optical sheet. In this case, when pressure is applied so as to press the transfer surface of the transfer roll and the light incident end surfaces of the optical sheet, the paste component used for bonding the masking film adheres to the transfer roll as dirt. There is. Therefore, it is particularly effective to apply the present invention to the processing of such an optical sheet with a masking film.

Further, the heating means may include an induction coil provided in the transfer roll and a power supply unit that supplies current to the induction coil. By using a transfer roll with an induction coil in this way and passing a current through the induction coil to heat the transfer roll, the temperature distribution in the roll axis direction of the transfer roll is higher than when the transfer roll is heated with oil. It is made uniform. Therefore, by moving the transfer roll relative to the stage in the roll axis direction of the transfer roll, stable transfer accuracy can be achieved even if the contact location between the transfer surface of the transfer roll and the light incident end surface of the optical sheet is changed. Obtainable.

Further, the present invention in this aspect is an optical sheet processing method for forming a concavo-convex portion on a light incident end surface of an optical sheet made of a thermoplastic resin, the preparation step for preparing the optical sheet processing apparatus described above, and a transfer roll. By heating and moving the stage relative to the transfer roll in the direction of formation of the concavo-convex part while rotating the transfer roll in a state where pressure is applied so as to press the transfer surface and the light incident end surfaces, After the molding process for forming the concavo-convex portion on the light incident end face and the foreign substance adhering to the transfer surface after the molding process is performed, it is avoided that the light incident end face comes into contact with the foreign matter adhesion portion on the transfer surface. And an avoidance step of moving the transfer roll relative to the stage in the roll axis direction of the transfer roll.

In such an optical sheet processing method of the present invention, the transfer roll is heated and the transfer roll is rotated in a state where pressure is applied so as to press the transfer surface of the transfer roll and the light incident end faces of the optical sheet. By moving the stage relative to the transfer roll in the direction of forming the uneven portion, the uneven portion is imparted to the light incident end surface of the optical sheet. Thereby, unlike the case where an uneven | corrugated | grooved part is formed by cutting, since a swarf does not generate | occur | produce, the mixing and adhesion of the swarf to an optical sheet can be prevented.

In addition, when foreign matter adheres to the transfer surface of the transfer roll after forming the concavo-convex portion on the light entrance end surface of the optical sheet, it is avoided that the light entrance end surface comes into contact with the foreign matter attachment location on the transfer surface. In this manner, the transfer roll is moved relative to the stage in the roll axis direction of the transfer roll. As a result, even if the transfer surface of the transfer roll becomes dirty, the formation of uneven portions on the light incident end surface of the optical sheet is continuously performed on the clean transfer surface of the transfer roll without cleaning the transfer surface. Can do.

In another aspect, the present invention is an optical sheet processing apparatus for forming a concavo-convex portion on a light incident end surface of an optical sheet made of a thermoplastic resin, the stage supporting the optical sheet, and the optical supported by the stage. A metal transfer roll having a transfer surface for imparting a concavo-convex portion to the light incident end face of the sheet, and a stage disposed on the side corresponding to the transfer roll with respect to the stage, for setting a reference position of the optical sheet with respect to the transfer roll A positioning member, a pressing member for pressing the optical sheet against the positioning member, a heating unit for heating the transfer roll, a pressure applying unit for applying pressure so as to press the transfer surface and the light incident end surface, and a transfer roll. Rotating means for rotating, and moving means for moving the stage relative to the transfer roll in the direction of forming the concavo-convex portion A.

In addition, when the optical sheet is cut, a positioning member is arranged on the side corresponding to the transfer roll with respect to the stage, the optical sheet is pressed against the positioning member by the pressing member, and the reference position of the optical sheet with respect to the transfer roll is set. Even if the size of the optical sheet differs from one sheet to another due to the tolerance, the reference position of the optical sheet with respect to the transfer roll is always constant. Therefore, when a pressure is applied so as to press the transfer surface of the transfer roll and the light incident end surfaces of the optical sheet, the contact distance between the optical sheet and the transfer roll is always kept constant. Thereby, even if the size of the optical sheet is different, stable transfer accuracy can be obtained.

The positioning member may be a freely rotatable roller. In this case, the stage moves relative to the transfer roll relative to the transfer roll in a state where the optical sheet contacts the positioning member (roller) and the reference position of the optical sheet relative to the transfer roll is set. In this case, since the optical sheet moves relative to the transfer roll while the roller rotates, the optical sheet is prevented from being damaged.

Further, the pressing member may be at least one of a bar extending in the moving direction of the stage and a plurality of pins arranged side by side in the moving direction of the stage. In this case, the pressing member can be realized with a simple structure.

At this time, the bar has a plurality of pins protruding to the stage side, and the upper surface of the stage extends in the pressing direction of the optical sheet and is provided with a plurality of guide grooves for sliding each pin. Also good. In this case, when the bar is moved toward the positioning member and the optical sheet is pressed against the positioning member, the lower surface of the bar and the upper surface of the stage are prevented from being rubbed and damaged. Even when the optical sheet is thin, the optical sheet can be reliably pressed against the positioning member by the plurality of pins.

Furthermore, the depth of unevenness on the transfer surface may be 0.01 mm to 0.30 mm. Experiments and the like have revealed that when a large number of optical sheets (for example, about 50 sheets) are cut at once, a tolerance of about 0.1 mm at maximum is generated. For this reason, if the depth of the unevenness on the transfer surface of the transfer roll is in the above range, the influence of the contact distance between the optical sheet and the transfer roll on the transfer accuracy increases. Therefore, it is particularly effective to apply the present invention to a transfer roll having such a transfer surface.

The present invention in this aspect is an optical sheet processing method for forming a concavo-convex portion on a light incident end surface of an optical sheet made of a thermoplastic resin, the preparation step for preparing the above optical sheet processing apparatus, and an optical sheet on the stage In the supported state, the optical sheet is pressed against the positioning member by the pressing member to set the reference position of the optical sheet with respect to the transfer roll, the transfer roll is heated, and the transfer surface and the light incident end surface are pressed against each other. Forming a concavo-convex portion on the light incident end surface by moving the stage relative to the transfer roll while rotating the transfer roll while pressure is applied. It is characterized by.

In addition, the optical sheet is pressed against a positioning member arranged on the side corresponding to the transfer roll with respect to the stage, and the reference position of the optical sheet with respect to the transfer roll is set, so that the tolerance of the optical sheet can be reduced by the tolerance of the optical sheet. Even if the sizes differ one by one, the reference position of the optical sheet with respect to the transfer roll is always constant. Therefore, when a pressure is applied so as to press the transfer surface of the transfer roll and the light incident end surfaces of the optical sheet, the contact distance between the optical sheet and the transfer roll is always kept constant. Thereby, even if the size of the optical sheet is different, stable transfer accuracy can be obtained.

According to the present invention, it is possible to prevent chips from being mixed and adhered to the optical sheet. As a result, the quality of the optical sheet can be stabilized and the yield can be improved.
Further, according to one aspect of the present invention, even when the transfer surface of the transfer roll is contaminated, the formation of the uneven portion on the light incident end surface of the optical sheet is continuously performed on the clean transfer surface of the transfer roll. Can do. Thereby, the quality of the optical sheet can be stabilized and the yield can be improved.
In addition, according to one aspect of the present invention, stable transfer accuracy can be obtained even if the size of the optical sheet is different. Thereby, the quality of the optical sheet can be stabilized and the yield can be improved.
Moreover, according to one side of this invention, an uneven | corrugated | grooved part can be processed in an optical sheet in a short time, and productivity can be improved.
In addition, according to one aspect of the present invention, the processing tact of the optical sheet can be increased and the productivity can be improved.

It is a schematic sectional drawing which shows the liquid crystal display device containing the light-guide plate as an optical sheet manufactured by one Embodiment of the optical sheet manufacturing method concerning this invention. It is a perspective view of the light-guide plate shown in FIG. It is a flowchart which shows the process of manufacturing the light-guide plate shown in FIG. It is a schematic block diagram which shows the optical sheet processing apparatus used when performing a thermal transfer process to the light-incidence end surface of the light-guide plate shown in FIG. It is a figure which shows the uneven | corrugated | grooved part formed in the surrounding surface of the rigid roll part of the transfer metal mold | die shown in FIG. It is a schematic block diagram which shows the modification of the optical sheet processing apparatus shown in FIG. It is a schematic block diagram which shows the other modification of the optical sheet processing apparatus shown in FIG. It is a schematic block diagram which shows the modification of the optical sheet processing apparatus shown in FIG. It is a figure which shows the other uneven | corrugated | grooved part formed in the surrounding surface of the rigid roll part of the transfer metal mold | die shown in FIG. It is a table | surface which shows the conditions and result when an uneven | corrugated | grooved part is heat-transfer-processed on the light-incidence end surface of a light-guide plate with a transfer metal mold | die. It is a schematic sectional drawing which shows the liquid crystal display device containing the light-guide plate as an optical sheet manufactured by one Embodiment of the optical sheet manufacturing method concerning this invention. It is a perspective view of the light-guide plate shown in FIG. It is a flowchart which shows the process of manufacturing the light-guide plate shown in FIG. It is a schematic block diagram which shows the optical sheet processing apparatus used when performing a thermal transfer process to the light-incidence end surface of the light-guide plate shown in FIG. It is a figure which shows the uneven | corrugated part for transcription | transfer provided in the surrounding surface of the rigid roll part of the transfer metal mold | die shown in FIG. 14, and the uneven | corrugated | grooved part formed in the light-incidence end surface of a light-guide plate by thermal transfer process. It is a schematic block diagram which shows the modification of the optical sheet processing apparatus shown in FIG. It is a schematic block diagram which shows the other modification of the optical sheet processing apparatus shown in FIG. It is a schematic block diagram which shows the modification of the optical sheet processing apparatus shown in FIG. It is a figure which shows the other uneven | corrugated | grooving part for transcription | transfer provided in the surrounding surface of the rigid roll part of the transfer metal mold | die shown in FIG. It is a table | surface which shows the conditions and results when an uneven | corrugated | grooved part is heat-transfer processed to the light-incidence end surface of a light-guide plate with a transfer metal mold | die. It is a schematic sectional drawing which shows the liquid crystal display device containing the light-guide plate which is an optical sheet obtained by one Embodiment of the optical sheet processing apparatus concerning this invention. It is a perspective view of the light-guide plate shown in FIG. It is a flowchart which shows the process of manufacturing the light-guide plate shown in FIG. It is a top view which shows one Embodiment of the optical sheet processing apparatus concerning this invention. It is a front view of the optical sheet processing apparatus shown in FIG. FIG. 26 is a main portion sectional view taken along line XXVI-XXVI in FIG. 25. It is a principal part enlarged view of FIG. FIG. 26 is an enlarged cross-sectional view taken along line XXVIII-XXVIII in FIG. 25. FIG. 25 is a perspective view schematically showing the optical sheet processing apparatus shown in FIG. 24 and the like. It is a conceptual diagram which shows the process of shape | molding a light-guide plate using the optical sheet processing apparatus shown in FIG. It is a conceptual diagram which shows the other process of shape | molding a light-guide plate using the optical sheet processing apparatus shown in FIG. It is a conceptual diagram which shows the further another process of shape | molding a light-guide plate using the optical sheet processing apparatus shown in FIG. FIG. 25 is a view showing a modification of the mechanism for rotating the transfer roll and moving the stage in the optical sheet processing apparatus shown in FIG. 24 and the like. It is a schematic sectional drawing which shows the liquid crystal display device containing the light-guide plate which is an optical sheet obtained by one Embodiment of the optical sheet processing apparatus concerning this invention. It is a perspective view of the light-guide plate shown in FIG. It is a flowchart which shows the process of manufacturing the light-guide plate shown in FIG. It is a top view which shows one Embodiment of the optical sheet processing apparatus concerning this invention. It is a front view of the optical sheet processing apparatus shown in FIG. FIG. 39 is a cross-sectional view of the main part of the line XXXIX-XXXIX in FIG. 38. It is a principal part enlarged view of FIG. FIG. 39 is an enlarged cross-sectional view of the main part XLI-XLI in FIG. 38. FIG. 38 is a perspective view schematically showing the optical sheet processing apparatus shown in FIG. 37 and the like. FIG. 40 is a cross-sectional view showing a state where the transfer roll is raised in the optical sheet processing apparatus shown in FIG. It is a conceptual diagram which shows an example of the process of shape | molding a light-guide plate using the optical sheet processing apparatus shown in FIG. It is a perspective view which shows the modification of the optical sheet processing apparatus shown in FIG. It is a schematic sectional drawing which shows the liquid crystal display device containing the light-guide plate which is an optical sheet obtained by one Embodiment of the optical sheet processing apparatus concerning this invention. It is a perspective view of the light-guide plate shown in FIG. It is a flowchart which shows the process of manufacturing the light-guide plate shown in FIG. It is a top view which shows one Embodiment of the optical sheet processing apparatus concerning this invention. It is a front view of the optical sheet processing apparatus shown in FIG. FIG. 52 is a main-portion cross-sectional view taken along line LI-LI in FIG. It is a principal part enlarged view of FIG. FIG. 52 is an enlarged cross-sectional view of a main part taken along line LIII-LIII in FIG. 50. FIG. 50 is a perspective view schematically showing the optical sheet processing apparatus shown in FIG. 49 and the like. It is a conceptual diagram which shows the uneven | corrugated | grooving part for transfer formed in the transfer surface of the transfer roll shown in FIG. It is a conceptual diagram which shows a mode that a bending stress is applied to the protrusion part of the light-guide plate from the clamp plate shown in FIG. FIG. 55 is a perspective view showing a structure for setting a reference position of the light guide plate with respect to the transfer roll shown in FIG. 54. It is a top view which shows a mode that the light-guide plate shown in FIG. 57 is pressed on the positioning roller, and a light-guide plate is moved toward a transfer roll in the state. It is a conceptual diagram which shows an example of the process of shape | molding a light-guide plate using the optical sheet processing apparatus shown in FIG. FIG. 56 is a perspective view showing a modification of the structure for setting the reference position of the light guide plate with respect to the transfer roll shown in FIG. 54.

Hereinafter, an optical sheet manufacturing method and an optical sheet processing apparatus according to the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 is a schematic cross-sectional view showing a liquid crystal display device including a light guide plate as an optical sheet manufactured by an embodiment of the optical sheet manufacturing method according to the present invention. In the figure, a liquid crystal display device 101 according to the present embodiment is used for a liquid crystal television, for example. The liquid crystal display device 101 includes a liquid crystal panel 102 and an edge type backlight unit 103 disposed on the back side of the liquid crystal panel 102. The thickness of the liquid crystal panel 102 is about 1.8 mm, for example.

The backlight unit 103 has a box-shaped metal backlight housing 104. A plurality of electronic components 105 are provided on the back surface (back surface) of the backlight housing 104 via a substrate (not shown). A plurality of LEDs 106 for irradiating light are attached to the inner wall surfaces of the backlight housing 104 facing each other.

In the backlight housing 104, a light guide plate 107 having a rectangular cross section for guiding the light emitted from the LED 106 to the liquid crystal panel 102 is accommodated via a reflection sheet 108. The reflection sheet 108 is disposed on the back surface (back surface) side of the light guide plate 107. As shown in FIG. 2, the light incident end face 107a of the light guide plate 107 is provided with a concavo-convex portion 109 having a substantially corrugated cross section. The thickness of the light guide plate 107 is 3 mm, for example.

The light guide plate 107 is made of a thermoplastic resin. Specifically, the light guide plate 107 is made of an amorphous resin having high dimensional accuracy, impact strength, and transparency. Examples of the amorphous resin include polymethyl methacrylate resin (PMMA), polystyrene (PS), polycarbonate (PC), and cycloolefin polymer (COP).

The light emitted from the LED 106 is incident on the light incident end surface 107 a of the light guide plate 107. The back surface of the light guide plate 107 is a reflective surface that reflects the light emitted from the LED 106, and the front surface of the light guide plate 107 is a light output surface that emits the light emitted from the LED 106 and the light reflected by the reflective surface. It has become. The back surface (reflection surface) of the light guide plate 107 has a structure that easily reflects and scatters light, such as dot pattern printing with ink. Depending on the usage, a lenticular shape, a prism shape, or the like may be formed on the light exit surface.

On the front side of the light guide plate 107, an optical film group 110 formed by laminating a plurality (three in this case) of optical films is disposed. The thickness of the optical film group 110 is, for example, about 0.2 mm. The edges of the light guide plate 107 and the optical film group 110 are fixed to the backlight housing 104 by a frame body 111 made of resin (for example, PC). The liquid crystal panel 102 is fixed to the backlight unit 103 by a metal frame body 112.

FIG. 3 is a flowchart showing a process of manufacturing the light guide plate 107 described above. In the figure, first, a light guide plate original plate is produced by a melt extrusion sheet forming process or the like (step S101). Subsequently, the light guide plate original plate is roughly cut with a panel saw, a running saw, or the like to obtain the light guide plate 107 (step S102). Subsequently, using a mirror finishing machine, the light incident end face 107a of the light guide plate 107 is mirror finished (step S103). Then, the uneven | corrugated | grooved part 109 is formed in the light-incidence end surface 107a by performing a thermal transfer process to the light-incidence end surface 107a of the light-guide plate 107 (step S104). Note that step S103 is not necessarily performed.

FIG. 4 is a schematic configuration diagram showing the optical sheet processing apparatus 120 used when step S104 of FIG. 3 is performed. In the figure, an optical sheet processing apparatus 120 includes a stage 121 that supports a light guide plate 107, and a clamp plate 122 that presses and clamps the light guide plate 107 placed on the stage 121 against the stage 121 from above. It has. Two positioning protrusions 123 for aligning the light guide plate 107 are provided on the upper surface of the stage 121.

The optical sheet processing apparatus 120 further includes a transfer mold 124 that performs thermal transfer on the light incident end surface 107 a of the light guide plate 107 placed on the stage 121. The transfer mold 124 includes a rotatable metal rigid roll portion 125. On the peripheral surface of the rigid roll portion 125, a transfer uneven portion 126 is formed along the circumferential direction of the rigid roll portion 125. The peripheral surface of the rigid roll portion 125 is a transfer surface 125 a for providing the uneven portion 109 to the light incident end surface 107 a of the light guide plate 107. The transfer uneven portion 126 is formed in a prism shape (triangular prism shape) with respect to the axial direction of the rigid roll portion 125 (see FIG. 5).

As shown in FIG. 5, the pitch (width) P of the concavo-convex portion for transfer 126 is preferably 10 μm to 500 μm, and more preferably 10 μm to 200 μm. The height (depth) H of the uneven portion for transfer 126 is preferably 10 μm to 300 μm in accordance with the pitch P of the uneven portion for transfer 126. In FIG. 5, for convenience, the transfer uneven portions 126 are shown to be arranged in a straight line.

In addition, the optical sheet processing apparatus 120 is configured to press the heating unit 127 that heats the transfer mold 124, the transfer surface 125 a of the rigid roll unit 125 of the transfer mold 124, and the light incident end surface 107 a of the light guide plate 107. A pressure application unit 128 that applies pressure to 121, a movement drive unit 129 that moves the stage 121 in a direction perpendicular to the pressure application direction (the direction of arrow A in FIG. 4), and a rotation that rotates the rigid roll unit 125 And a drive unit 130.

When the uneven portion 109 is formed on the light incident end face 107a of the light guide plate 107 using such an optical sheet processing apparatus 120, first, the one light guide plate 107 is placed on the stage 121, and the clamp plate 122 is in that state. Thus, the light guide plate 107 is clamped. Note that a masking film may be bonded to the light guide plate 107 mounted on the stage 121 to prevent damage.

Then, the transfer mold 124 is heated by the heating unit 127. At this time, the heating temperature of the transfer mold 124 is preferably equal to or higher than the Vicat softening temperature of the thermoplastic resin forming the light guide plate 107 and is equal to or lower than the Vicat softening temperature of the thermoplastic resin + 50 ° C. It is more preferable that the Vicat softening temperature of the resin + 5 ° C. or higher and the Vicat softening temperature of the thermoplastic resin + 35 ° C. or lower. For example, when PMMA is used as the thermoplastic resin, the Vicat softening temperature of PMMA is 104 ° C. Therefore, the heating temperature of the transfer mold 124 is preferably 104 ° C. to 154 ° C., more preferably 110 ° C. to 140 ° C., and further preferably 120 ° C. to 130 ° C.

Further, by applying a certain pressure to the stage 121 by the pressure application unit 128, the transfer surface 125 a of the rigid roll unit 125 and the light incident end surface 107 a of the light guide plate 107 are pressed against each other. At this time, since the transfer surface 125a and the light incident end surface 107a are not in surface contact but in line contact, the pressing pressure can be reduced accordingly. The pressing pressure set at this time is preferably 0.05 MPa to 50 MPa, more preferably 0.2 MPa to 0.6 MPa. Further, since the light guide plate 107 is clamped by the clamp plate 122, the pressing pressure does not escape above the light guide plate 107, and the transfer surface 125a and the light incident end surface 107a can be effectively pressed.

In this state, the stage 121 is moved in the direction perpendicular to the pressure application direction with respect to the transfer mold 124 by the movement driving unit 129, and the rigid roll unit 125 is rotated by the rotation driving unit 130. Since the rotation of the light guide plate 107 relatively moves along the light incident end surface 107 a of the light guide plate 107, the transfer uneven portion 126 of the rigid roll portion 125 is transferred to the light incident end surface 107 a of the light guide plate 107. At this time, the movement of the stage 121 and the rotation of the rigid roll unit 125 are performed in synchronization. The transfer time is preferably 1 to 10 seconds, more preferably 1 to 5 seconds. Thus, the uneven portion 109 corresponding to the transfer uneven portion 126 is formed on the light incident end surface 107 a of the light guide plate 107.

In the optical sheet processing apparatus 120, by applying pressure to the stage 121, the transfer surface 125a of the rigid roll portion 125 and the light incident end surface 107a of the light guide plate 107 are pressed against each other. By applying pressure to the rigid roll portion 125, the transfer surface 125 a of the rigid roll portion 125 and the light incident end surface 107 a of the light guide plate 107 may be pressed against each other.

FIG. 6 is a schematic configuration diagram showing a modification of the optical sheet processing apparatus 120 shown in FIG. In the same figure, the optical sheet processing apparatus 120 of this modification is arranged in a direction perpendicular to the pressure application direction with respect to the stage 121 (in the direction of arrow B in FIG. 6) instead of the movement drive unit 129. ) Is provided. Therefore, the rigid roll portion 125 itself moves along the light incident end surface 107a of the light guide plate 107 while rotating. Other configurations are the same as those shown in FIG. Even in this case, the transfer uneven portion 126 of the rigid roll portion 125 can be transferred to the light incident end surface 107 a of the light guide plate 107.

FIG. 7 is a schematic configuration diagram showing another modification of the optical sheet processing apparatus 120 shown in FIG. In the figure, an optical sheet processing apparatus 120 of this modification includes a stage 132 that supports a plurality of light guide plates 107 in a stacked state. Other configurations are the same as those shown in FIG. In this case, the concavo-convex portions for transfer 126 of the rigid roll portion 125 can be collectively transferred to the light incident end surfaces 107 a of the plurality of light guide plates 107. Therefore, productivity can be improved.

FIG. 8 is a schematic configuration diagram showing a modification of the optical sheet processing apparatus 120 shown in FIG. In the same figure, the optical sheet processing apparatus 120 of this modified example replaces the movement drive unit 129 with the rigid roll unit 125 in the direction perpendicular to the pressure application direction with respect to the stage 132 (the direction of arrow B in FIG. 8). A movement drive unit 131 for movement is provided. Other configurations are the same as those shown in FIG. Also in this case, the uneven portions for transfer 126 of the rigid roll portion 125 can be collectively transferred to the light incident end surfaces 107 a of the plurality of light guide plates 107.

As described above, in the present embodiment, the transfer mold 124 is heated, and the transfer surface 125a of the rigid roll portion 125 of the transfer mold 124 and the light incident end surface 107a of the light guide plate 107 are pressed against each other to thereby form the rigid roll portion. Since the uneven portion for transfer 126 provided on the transfer surface 125a of 125 is transferred to the light incident end surface 107a of the light guide plate 107, the uneven portion 109 is formed on the light incident end surface 107a of the light guide plate 107. As in the case where the uneven portion 109 is formed on the light incident end surface 107a of the light guide plate 107 by mechanical cutting processing or the like, chips are not generated. For this reason, since chips do not adhere to or mix in the light guide plate 107, the quality of the product can be stabilized and the yield can be improved.

At this time, by setting the heating temperature of the transfer mold 124 to be equal to or higher than the Vicat softening temperature of the thermoplastic resin forming the light guide plate 107, the light incident end surface 107a of the light guide plate 107 is appropriately softened. The transfer uneven portion 126 can be satisfactorily transferred to the light incident end surface 107a of the light guide plate 107, and the light guide plate 107 can be prevented from cracking. Further, since the heating temperature of the transfer mold 124 is set to the Vicat softening temperature of the thermoplastic resin forming the light guide plate 107 + 50 ° C. or less, the melt flow of the thermoplastic resin is prevented, so the elastic modulus of the thermoplastic resin. Is suppressed, and the light guide plate 107 is hardly deformed. In addition, significant contamination of the transfer mold 124 can be prevented.

Further, by setting the pressing pressure of the transfer surface 125a of the rigid roll portion 125 and the light incident end surface 107a of the light guide plate 107 to 0.05 MPa or more, the transfer uneven portion 126 of the rigid roll portion 125 is changed to the light incident end surface of the light guide plate 107. 107a can be transferred more satisfactorily. Further, by making the pressing pressure of the transfer surface 125a of the rigid roll portion 125 and the light incident end surface 107a of the light guide plate 107 50 MPa or less, it is possible to further prevent the light guide plate 107 from being cracked.

Furthermore, when the uneven portion 109 is formed on the light incident end surface 107a of the light guide plate 107 by cutting, it takes time to process the fine uneven portion 109, and it is difficult to reduce the pitch of the uneven portion 109. There is a problem that the uneven portion 109 is changed due to wear of the cutting tool. In the present embodiment, the uneven portion 109 is formed on the light incident end surface 107a of the light guide plate 107 by thermal transfer processing using the transfer mold 124. Therefore, the heating temperature of the transfer mold 124, the transfer surface 125a of the rigid roll portion 125, and By controlling the pressing pressure and pressing time of the light incident end face 107a of the light guide plate 107, the processing time can be easily reduced. Further, by producing and using an arbitrary transfer mold, it is possible to form the uneven portions 109 having various shapes, and it is possible to realize a narrow pitch of the uneven portions 109.

Note that the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the prism-shaped transfer uneven portion 126 is formed on the transfer surface 125a of the rigid roll portion 125. However, the shape of the transfer uneven portion 126 is not particularly limited to the prism shape, and FIG. A lenticular shape as shown in FIG. Even in this case, it is preferable that the pitch P of the transfer uneven portion 126 is 10 μm to 500 μm and the height H of the transfer uneven portion 126 is 10 μm to 300 μm. In addition, the shape of the uneven portion 109 may be a pyramid shape, a mat shape, or the like.

In the above embodiment, the transfer mold 124 has the rigid roll portion 125, and the peripheral surface of the rigid roll portion 125 becomes the transfer surface 125 a for providing the uneven portion 109 to the light incident end surface 107 a of the light guide plate 107. However, the transfer mold to be used is not particularly limited thereto. For example, the shape of the transfer mold may be a flat plate shape, and one side surface of the transfer mold may be a transfer surface for providing the uneven portion 109 on the light incident end surface 107a of the light guide plate 107.

Furthermore, although the said embodiment manufactures the light-guide plate 107 with which the backlight unit 103 of the liquid crystal display device 101 used for a liquid crystal television is equipped, the optical sheet manufacturing method of this invention is for illumination, for example It can also be applied to the production of an optical sheet as a decorative light guide plate.

[Experimental example 1]
Hereinafter, an example of the optical sheet manufacturing method according to the present invention will be described.

Using a transfer mold having a rigid roll part, the uneven part was thermally transferred to the light incident end face of the light guide plate. The used light guide plate is formed of PMMA (Vicat softening temperature: 104 ° C.). The temperature of the light guide plate is 25 ° C. On the peripheral surface of the rigid roll portion, a prism-shaped transfer uneven portion is provided. As the transfer mold, the apex angle θ (see FIG. 5) of the transfer uneven portion of the rigid roll portion is 110 degrees, and the pitch P of the transfer uneven portion is 100 μm, 200 μm, and 300 μm. . When the transfer unevenness pitch P is 100 μm, the transfer unevenness height H is 34.7 μm, and when the transfer unevenness pitch P is 200 μm, the transfer unevenness height. When H is 69.3 μm and the pitch P of the uneven portions for transfer is 300 μm, the height H of the uneven portions for transfer is 104.0 μm.

As shown in FIG. 10, the heating temperature of the transfer mold was any one of 110 ° C., 120 ° C., 130 ° C. and 140 ° C. The pressing pressure of the transfer surface of the rigid roll portion and the light incident end surface of the light guide plate was either 0.4 MPa or 0.6 MPa. The pressing time of the transfer surface of the rigid roll portion and the light incident end surface of the light guide plate was either 1 second or 5 seconds.

FIG. 10 shows the result of thermal transfer processing of the concavo-convex portion on the light incident end face of the light guide plate by the above transfer mold. FIG. 10 (a) is a table showing the results when a transfer mold having a transfer unevenness portion of the rigid roll portion having a pitch of 300 μm is used, and the pitches of the uneven portions of the light guide plate are all 300 μm. The height and the transfer rate are as shown in the table. FIG. 10 (b) shows the results when a transfer mold having a transfer uneven portion of the rigid roll portion having a pitch of 200 μm is used. The pitch of the uneven portion of the light guide plate is all 200 μm, and the height of the uneven portion. The transfer rate is as shown in the table. FIG. 10C shows the result when a transfer mold having a transfer unevenness portion of the rigid roll portion having a pitch of 100 μm is used. The unevenness portion pitches of the light guide plate are all 100 μm, and the height of the unevenness portion. The transfer rate is as shown in the table. The transfer rate is expressed by the following formula (see FIG. 5).
Transfer rate (%) = height / roughness height Hr of light guide plate / height / recession height H of rigid body roll portion

As can be seen from FIG. 10, when a transfer mold having a transfer rugged portion pitch of 100 μm and 200 μm in the rigid roll portion is used, a transfer mold having a transfer rugged portion pitch of 300 μm in the rigid roll portion is used. Compared with the case, the transfer rate tends to be higher. Also, when the heating temperature of the transfer mold is 120 ° C. and 130 ° C., the transfer rate tends to be higher than when the heating temperature of the transfer mold is 110 ° C. and 140 ° C.

Hereinafter, an optical sheet manufacturing method according to another embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

FIG. 11 is a schematic cross-sectional view showing a liquid crystal display device including a light guide plate as an optical sheet manufactured by an embodiment of the optical sheet manufacturing method according to the present invention. In the figure, a liquid crystal display device 201 according to the present embodiment is used for a liquid crystal television, for example. The liquid crystal display device 201 includes a liquid crystal panel 202 and an edge-type backlight unit 203 disposed on the back side of the liquid crystal panel 202. The thickness of the liquid crystal panel 202 is, for example, about 1.8 mm.

The backlight unit 203 has a box-shaped metal backlight housing 204. A plurality of electronic components 205 are provided on the back surface (back surface) of the backlight housing 204 via a substrate (not shown). A plurality of LEDs 206 for irradiating light are attached to the inner wall surfaces of the backlight housing 204 facing each other.

In the backlight housing 204, a light guide plate 207 having a rectangular cross section for guiding the light emitted from the LED 206 to the liquid crystal panel 202 is accommodated via a reflection sheet 208. The reflection sheet 208 is disposed on the back surface (back surface) side of the light guide plate 207. As shown in FIG. 12, the light incident end face 207a of the light guide plate 207 is provided with a concavo-convex portion 209 having a substantially corrugated cross section. The thickness of the light guide plate 207 is 4 mm, for example.

The light guide plate 207 is made of a thermoplastic resin. Specifically, the light guide plate 207 is made of an amorphous resin having high dimensional accuracy, impact strength, and transparency. Examples of the amorphous resin include polymethyl methacrylate resin (PMMA), polystyrene (PS), polycarbonate (PC), and cycloolefin polymer (COP).

The light emitted from the LED 206 is incident on the light incident end surface 207 a of the light guide plate 207. The back surface of the light guide plate 207 is a reflective surface that reflects the light emitted from the LED 206, and the front surface of the light guide plate 207 is a light output surface that emits the light emitted from the LED 206 and the light reflected by the reflective surface. It has become. The back surface (reflection surface) of the light guide plate 207 has a structure that easily reflects and scatters light, such as dot pattern printing with ink.

On the front side of the light guide plate 207, an optical film group 210 formed by laminating a plurality (three in this case) of optical films is disposed. The thickness of the optical film group 210 is, for example, about 1 mm. The edges of the light guide plate 207 and the optical film group 210 are fixed to the backlight housing 204 by a frame body 211 made of resin (for example, PC). The liquid crystal panel 202 is fixed to the backlight unit 203 by a metal frame body 212.

FIG. 13 is a flowchart showing a process of manufacturing the light guide plate 207 described above. In the figure, first, a light guide plate original plate is produced by a melt extrusion sheet forming process or the like (step S201). Subsequently, the light guide plate original plate is roughly cut with a panel saw, a running saw, or the like to obtain the light guide plate 207 (step S202). Subsequently, the mirror finish is applied to the light incident end face 207a of the light guide plate 207 using a mirror finish machine (step S203). Subsequently, by performing thermal transfer processing on the light incident end surface 207a of the light guide plate 207, an uneven portion 209 is formed on the light incident end surface 207a (step S204). Note that step S203 is not necessarily performed.

FIG. 14 is a schematic configuration diagram showing the optical sheet processing apparatus 220 used when step S204 of FIG. 13 is performed. In the figure, an optical sheet processing apparatus 220 includes a stage 221 that supports a light guide plate 207, and a clamp plate 222 that presses and clamps the light guide plate 207 placed on the stage 221 against the stage 221 from above. It has. Two positioning protrusions 223 for aligning the light guide plate 207 are provided on the upper surface of the stage 221.

The optical sheet processing apparatus 220 further includes a transfer mold 224 that performs thermal transfer on the light incident end surface 207 a of the light guide plate 207 placed on the stage 221. The transfer die 224 has a rotatable metal rigid roll 225.

On the peripheral surface of the rigid roll portion 225, an uneven portion for transfer 226 is formed along the circumferential direction of the rigid roll portion 225. The peripheral surface of the rigid roll portion 225 is a transfer surface 225 a for providing the uneven portion 209 to the light incident end surface 207 a of the light guide plate 207. The transfer uneven portion 226 is formed in a prism shape (triangular prism shape) with respect to the axial direction of the rigid roll portion 225 (see FIG. 15). A flat surface is not provided at the base of the uneven portion for transfer 226.

As shown in FIG. 15, the apex angle θ of the uneven portion for transfer 226 is 60 ° to 140 °, preferably 80 ° to 120 °. The pitch (width) Wa of the concavo-convex portion for transfer 226 is 10 μm to 1000 μm, preferably 30 μm to 400 μm. In FIG. 15, for the sake of convenience, the transfer concavo-convex portions 226 are shown to be arranged in a straight line.

Further, the optical sheet processing apparatus 220 is configured so that the heating unit 227 that heats the transfer mold 224, the transfer surface 225a of the rigid roll unit 225 of the transfer mold 224, and the light incident end surface 207a of the light guide plate 207 are pressed against each other. A pressure applying unit 228 that applies pressure to the 221; a movement driving unit 229 that moves the stage 221 in a direction perpendicular to the direction of applying pressure (the direction of arrow A in FIG. 14); and a rotation that rotates the rigid roll unit 225. And a drive unit 230.

When the uneven portion 209 is formed on the light incident end surface 207a of the light guide plate 207 using such an optical sheet processing apparatus 220, the light guide plate 207 is first placed on the stage 221, and the clamp plate 222 is in that state. Thus, the light guide plate 207 is clamped.

Then, the transfer mold 224 is heated by the heating unit 227. At this time, the heating temperature of the transfer mold 224 is preferably higher than the Vicat softening temperature of the thermoplastic resin forming the light guide plate 207 and lower than the Vicat softening temperature of the thermoplastic resin + 40 ° C. For example, when PMMA is used as the thermoplastic resin, the Vicat softening temperature of PMMA is 104 ° C. Therefore, the heating temperature of the transfer mold 224 is preferably 104 ° C. to 144 ° C., more preferably 110 ° C. to 140 ° C.

Further, by applying a certain pressure to the stage 21 by the pressure applying unit 228, the transfer surface 225a of the rigid roll unit 225 and the light incident end surface 207a of the light guide plate 207 are pressed against each other. The pressing pressure set at this time is preferably 0.05 MPa to 50 MPa, more preferably 0.2 MPa to 0.6 MPa.

In this state, the stage 221 is moved in the direction perpendicular to the pressure application direction with respect to the transfer mold 224 by the movement drive unit 229 and the rigid roll unit 225 is rotated by the rotation drive unit 230, thereby causing the rigid roll unit 225. , While rotating, relatively moves along the light incident end surface 207 a of the light guide plate 207, so that the transfer uneven portion 226 of the rigid roll portion 225 is transferred to the light incident end surface 207 a of the light guide plate 207. At this time, the movement of the stage 221 and the rotation of the rigid roll unit 225 are performed in synchronization. Thereby, the thermoplastic resin forming the light guide plate 207 is filled in the transfer surface 225a of the rigid roll portion 225, and the uneven portion 209 is formed on the light incident end surface 207a of the light guide plate 207.

At this time, the transfer mold 224 and the light guide plate 207 are released before the thermoplastic resin forming the light guide plate 207 is completely filled in the transfer surface 225 a of the rigid roll portion 225. Here, complete filling refers to filling in which there is no thermoplastic resin unfilled space on the transfer surface 225a and the transfer rate is 100%. As a result, as shown in FIG. 15, a flat surface is formed at the tip of the concavo-convex portion 209. That is, the concavo-convex portion 209 has a shape in which regions of the flat surface of the tip portion (tip portion flat region) and concave regions (concave region) are alternately arranged. The flat surface referred to here includes not only a completely flat surface but also a surface that is nearly flat. Therefore, the uneven portion 209 having a transfer rate of 100% is never obtained. The transfer rate is expressed by the following formula (see FIG. 15).
Transfer rate (%) = height H ′ of the uneven portion of the light guide plate / height H of the uneven portion for transfer of the rigid roll portion

Here, when the length of the tip flat region is F ′, the length of the concave region is Wa ′, and the height of the uneven portion 209 is H ′ at one pitch of the uneven portion 209, F ′ / Wa ′. Is 10% to 300%, preferably 20% to 100%, and the transfer mold 224 is heated so that H ′ / Wa ′ is 0.15 to 0.65, preferably 0.25 to 0.55. The temperature, the pressing pressure and pressing time of the transfer surface 225a of the rigid roll unit 225 and the light incident end surface 207a of the light guide plate 207 are set. At this time, F ′ / Wa ′ decreases as the heating temperature increases, F ′ / Wa ′ decreases as the pressing pressure increases, and F ′ / Wa ′ decreases as the pressing time increases. Note that when the heating temperature of the transfer mold 224 is increased, if the heating temperature is increased too much, F ′ / Wa ′ tends to increase, so the heating temperature of the transfer mold 224 is set as described above. It is preferable that the temperature is not lower than the Vicat softening temperature of the thermoplastic resin forming the light guide plate 207 and not higher than the Vicat softening temperature of the thermoplastic resin + 40 ° C.

In the optical sheet processing apparatus 220, pressure is applied to the stage 221, and the transfer surface 225a of the rigid roll unit 225 and the light incident end surface 207a of the light guide plate 207 are pressed against each other. By applying pressure to the rigid roll unit 225, the transfer surface 225a of the rigid roll unit 225 and the light incident end surface 207a of the light guide plate 207 may be pressed against each other.

FIG. 16 is a schematic configuration diagram showing a modification of the optical sheet processing apparatus 220 shown in FIG. In the same figure, the optical sheet processing apparatus 220 of this modification is arranged in the direction perpendicular to the pressure application direction with respect to the stage 221 (in the direction of arrow B in FIG. 16) instead of the movement drive unit 229. ) Is moved. Therefore, the rigid roll unit 225 itself moves along the light incident end surface 207a of the light guide plate 207 while rotating. Other configurations are the same as those shown in FIG. Even in this case, the transfer uneven portion 226 of the rigid roll portion 225 can be transferred to the light incident end surface 207 a of the light guide plate 207.

FIG. 17 is a schematic configuration diagram showing another modification of the optical sheet processing apparatus 220 shown in FIG. In the figure, an optical sheet processing apparatus 220 according to this modification includes a stage 232 that supports a plurality of light guide plates 207 in a stacked state. Other configurations are the same as those shown in FIG. In this case, the concavo-convex portion 226 for transfer of the rigid roll portion 225 can be collectively transferred to the light incident end surfaces 207 a of the plurality of light guide plates 207. Therefore, productivity can be improved.

FIG. 18 is a schematic configuration diagram showing a modification of the optical sheet processing apparatus 220 shown in FIG. In the same figure, the optical sheet processing apparatus 220 of this modified example replaces the movement drive unit 229 with a rigid roll unit 225 in a direction perpendicular to the pressure application direction with respect to the stage 232 (in the direction of arrow B in FIG. 18). A movement drive unit 231 for movement is provided. Other configurations are the same as those shown in FIG. Also in this case, the transfer uneven portion 226 of the rigid roll portion 225 can be collectively transferred to the light incident end surfaces 207 a of the plurality of light guide plates 207.

As described above, in the present embodiment, the transfer mold 224 is heated, and the transfer surface 225a of the rigid roll portion 225 of the transfer mold 224 and the light incident end surface 207a of the light guide plate 207 are pressed against each other to thereby form a rigid roll. Since the transfer uneven portion 226 provided on the transfer surface 225a of the portion 225 is transferred to the light incident end surface 207a of the light guide plate 207, the uneven portion 209 is formed on the light incident end surface 207a of the light guide plate 207. Chips are not generated unlike the case where the uneven portion 209 is formed on the light incident end surface 207a of the light guide plate 207 by mechanical cutting with a cutting tool or the like. For this reason, since chips do not adhere to or mix in the light guide plate 207, the quality of the product can be stabilized and the yield can be improved.

At this time, by setting the heating temperature of the transfer mold 224 to be equal to or higher than the Vicat softening temperature of the thermoplastic resin forming the light guide plate 207, the light incident end face 207a of the light guide plate 207 is appropriately softened. The transfer uneven portion 226 can be satisfactorily transferred to the light incident end surface 207a of the light guide plate 207, and the light guide plate 207 can be prevented from cracking. Moreover, since the melting temperature of the thermoplastic resin is prevented by setting the heating temperature of the transfer mold 224 to the Vicat softening temperature of the thermoplastic resin forming the light guide plate 207 + 40 ° C. or less, the elastic modulus of the thermoplastic resin Is suppressed, and the light guide plate 207 is hardly deformed. In addition, significant contamination of the transfer mold 224 can be prevented.

Further, by setting the pressing pressure of the transfer surface 225a of the rigid roll portion 225 and the light incident end surface 207a of the light guide plate 207 to 0.05 MPa or more, the transfer uneven portion 226 of the rigid roll portion 225 is changed to the light incident end surface of the light guide plate 207. It is possible to transfer more favorably to 207a. Further, by making the pressing pressure of the transfer surface 225a of the rigid roll portion 225 and the light incident end surface 207a of the light guide plate 207 50 MPa or less, it is possible to further prevent the light guide plate 207 from cracking.

Further, when the uneven portion 209 is formed on the light incident end surface 207a of the light guide plate 207 by cutting, it takes time to process the fine uneven portion 209. In this embodiment, since the uneven portion 209 is formed on the light incident end surface 207a of the light guide plate 207 by thermal transfer processing using the transfer mold 224, the heating temperature of the transfer mold 224, the transfer surface 225a of the rigid roll unit 225, and By controlling the pressing pressure and pressing time between the light incident end faces 207a of the light guide plate 207, it is possible to easily reduce the processing time of the uneven portion 209.

Further, in this embodiment, the transfer mold 224 and the light guide plate 207 are released before the thermoplastic resin forming the light guide plate 207 is completely filled in the transfer surface 225a of the rigid roll portion 225. The processing time of the part 209 can be further shortened. Thereby, the tact time of product manufacture becomes short and productivity can be improved.

At this time, before the thermoplastic resin forming the light guide plate 207 is completely filled in the transfer surface 225a of the rigid roll portion 225, the transfer mold 224 and the light guide plate 207 are separated from each other. As shown in FIG. 15, the shape of the concavo-convex portion 209 formed on the light incident end surface 207a is a shape in which a flat tip end region and a concave region are combined. For this reason, the optical characteristics (light diffusibility) of the light guide plate 207 are improved. Moreover, since the front-end | tip part of the uneven | corrugated | grooved part 209 is a flat surface without being sharpened, the chip | tip of the uneven | corrugated | grooved part 209 can be prevented from being chipped.

Note that the present invention is not limited to the above embodiment. For example, in the above embodiment, the base of the transfer uneven portion 226 provided on the transfer surface 225 a of the rigid roll portion 225 has no flat surface, but a flat surface may be formed at the base of the transfer uneven portion 226. That is, the uneven portion for transfer 226 may have a shape in which regions of the flat surface of the base portion (base portion flat region) and convex regions (convex region) are alternately arranged. At this time, when the ratio F / Wa (see FIG. 15) of the length F of the base flat region to the length Wa of the convex region at one pitch of the concave and convex portions for transfer 226 is 0% to 50%, The ratio F ′ / Wa ′ (see FIG. 15) of the length F ′ of the flat tip end region and the length Wa ′ of the concave region at one pitch of the portion 209 is 10% to 300%, preferably 20% to 80%. It is preferable to process the uneven portion 209 so that

Further, in the above-described embodiment, the prism-shaped transfer uneven portion 226 is formed on the transfer surface 225a of the rigid roll portion 225. However, the shape of the transfer uneven portion 226 is not particularly limited to a prism shape. A lenticular lens shape as shown in FIG.

Furthermore, although the said embodiment manufactures the light-guide plate 207 with which the backlight unit 203 of the liquid crystal display device 201 used for a liquid crystal television is equipped, the optical sheet manufacturing method of this invention is for illumination, for example, It can also be applied to the production of an optical sheet as a decorative light guide plate.

[Experimental example 2]
Hereinafter, an example of the optical sheet manufacturing method according to the present invention will be described.

Using the above-mentioned transfer mold, the uneven transfer portion was thermally transferred to the light incident end face of the light guide plate. The used light guide plate is formed of PMMA (Vicat softening temperature: 104 ° C.). The temperature of the light guide plate is 25 ° C. On the peripheral surface of the rigid roll portion of the transfer mold, there are provided prism-shaped or lenticular-shaped transfer uneven portions. As the rigid roll portion provided with the prism-shaped uneven portion for transfer, the apex angle θ (see FIG. 15) of the uneven portion for transfer is 110 degrees, and the pitch Wa (see FIG. 15) of the uneven portion for transfer is 300 μm. Alternatively, 400 μm was used, and the ratio H / Wa between the pitch Wa and the height H (see FIG. 15) of the uneven portions for transfer was 0.347. In addition, as the rigid roll portion provided with the lenticular-shaped uneven portion for transfer, the pitch Wa (see FIG. 19) of the uneven portion for transfer is 400 μm, and the pitch Wa and the height H (see FIG. 19) of the uneven portion for transfer. And a ratio H / Wa of 0.455 was used. Then, using such a transfer mold, an uneven portion was formed on the light incident end face of the light guide plate by the method described above.

At this time, as shown in FIG. 20, the heating temperature of the transfer mold was any one of 110 ° C., 120 ° C., 130 ° C., 140 ° C. and 150 ° C. The pressing pressure between the transfer surface of the rigid roll part and the light incident end surfaces of the light guide plate was any of 0.2 MPa, 0.4 MPa, and 0.6 MPa. The pressing time between the transfer surface of the rigid roll portion and the light incident end surfaces of the light guide plate was 5 seconds or 10 seconds.

The uneven portion formed on the light incident end face of the light guide plate obtained by the above method was evaluated with a laser measuring instrument (“LT-9000” manufactured by Keyence), and the height H ′ of the uneven portion was measured. Then, from the height H ′ of the concavo-convex part, the length F ′ of the flat part at the tip of the concavo-convex part and the length Wa ′ of the concave part were calculated to obtain F ′ / Wa ′ and H ′ / Wa ′. Moreover, the transfer rate of the uneven part for transfer was calculated.

The result is shown in FIG. As can be seen from FIG. 20, before the thermoplastic resin forming the light guide plate is completely filled into the transfer surface of the rigid roll portion of the transfer die, the transfer mold and the light guide plate are separated to transfer the light guide plate. As a result, there is no increase in the transfer rate of the concavo-convex portion for use, and a concavo-convex portion having a shape in which the flat end region and the concave region are combined is obtained. At this time, the transfer rate and F ′ / Wa ′ change by changing the heating temperature of the transfer mold, the pressing pressure and pressing time between the transfer surface of the rigid roll portion and the light incident end surface of the light guide plate.

Hereinafter, an optical sheet processing apparatus and method according to another aspect of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

FIG. 21 is a schematic cross-sectional view showing a liquid crystal display device including a light guide plate which is an optical sheet obtained by one embodiment of the optical sheet processing apparatus according to the present invention. In the figure, a liquid crystal display device 301 according to this embodiment is used for a liquid crystal television, for example. The liquid crystal display device 301 includes a liquid crystal panel 302 and an edge type backlight unit 303 disposed on the back side of the liquid crystal panel 302. The thickness of the liquid crystal panel 302 is, for example, about 1.8 mm.

The backlight unit 303 has a box-shaped metal backlight housing 304. A plurality of electronic components 305 are provided on the back surface (back surface) of the backlight housing 304 via a substrate (not shown). A plurality of LEDs 306 for irradiating light are attached to the inner wall surfaces of the backlight housing 304 facing each other.

In the backlight housing 304, a light guide plate 307 having a rectangular cross section for guiding the light emitted from the LED 306 to the liquid crystal panel 302 is accommodated via a reflection sheet 308. As shown in FIG. 22, the light incident end surface 307a of the light guide plate 307 is provided with a concavo-convex portion 309 having a substantially corrugated cross section. The thickness of the light guide plate 307 is 3 mm, for example.

The light guide plate 307 is made of a thermoplastic resin. Specifically, the light guide plate 307 is made of an amorphous resin having high dimensional accuracy, impact strength, and transparency. Examples of the amorphous resin include polymethyl methacrylate resin (PMMA), polystyrene (PS), polycarbonate (PC), and cycloolefin polymer (COP).

The light emitted from the LED 306 enters the light incident end surface 307a of the light guide plate 307. The back surface of the light guide plate 307 is a reflective surface that reflects the light emitted from the LED 306, and the front surface of the light guide plate 307 is a light output surface that emits the light emitted from the LED 306 and the light reflected by the reflective surface. It has become. The back surface (reflection surface) of the light guide plate 307 has a structure that easily reflects and scatters light, such as dot pattern printing with ink.

On the front side of the light guide plate 307, an optical film group 310 formed by laminating a plurality (three in this case) of optical films is disposed. The thickness of the optical film group 310 is, for example, about 0.2 mm. The edges of the light guide plate 307 and the optical film group 310 are fixed to the backlight housing 304 by a frame body 311 made of resin (for example, PC). The liquid crystal panel 302 is fixed to the backlight unit 303 by a metal frame body 312.

FIG. 23 is a flowchart showing a process of manufacturing the light guide plate 307. In the figure, first, an original light guide plate is produced by a melt extrusion sheet forming process or the like (step S301). Subsequently, the light guide plate original plate is roughly cut and cut using a panel saw, a running saw, or the like to obtain the light guide plate 307 (step S302). Subsequently, the mirror surface processing is performed on the light incident end surface 307a of the light guide plate 307 using a mirror processing machine (step S303). Then, the uneven | corrugated | grooved part 309 is formed in the light-incidence end surface 307a by performing a thermal transfer process to the light-incidence end surface 307a of the light-guide plate 307 (step S304). Note that step S303 is not necessarily performed.

FIG. 24 is a plan view showing an embodiment of the optical sheet processing apparatus according to the present invention. 25 is a front view of the optical sheet processing apparatus shown in FIG. 24, FIG. 26 is a sectional view taken along the line VI-VI in FIG. 25, and FIG. 27 is an enlarged view of the relevant part in FIG. 28 is an enlarged cross-sectional view taken along the line VIII-VIII in FIG. FIG. 29 is a perspective view schematically showing the optical sheet processing apparatus shown in FIG. In each figure, the optical sheet processing apparatus 320 of this embodiment is used when step S304 shown in FIG. 23 is implemented.

The optical sheet processing apparatus 320 includes an apparatus frame 321. A rack 322 is disposed at the center of the apparatus frame 321, and a metal transfer roll 323 is rotatably supported on the rack 322 (see FIG. 26). As shown in FIG. 29, an uneven surface portion 319 for transfer is formed on the outer peripheral surface 323 a of the transfer roll 323 along the circumferential direction of the transfer roll 323. The outer peripheral surface 323a of the transfer roll 323 serves as a transfer surface for imparting an uneven portion to the light incident end surface 307a of the light guide plate 307. The transfer concavo-convex portion 319 is formed in a prism shape or a lenticular shape with respect to the roll axis direction of the transfer roll 323, for example.

As shown in FIG. 26, the transfer roll 323 is an electric heater roll in which an induction coil 341 (heater unit) is incorporated. A power supply unit 342 that supplies high-frequency current to the induction coil 341 is disposed on the upper side of the transfer roll 323. The induction coil 341 and the power supply unit 342 constitute a heating unit that heats the transfer roll 323. As the transfer roll 323, an oil heater roll heated by oil may be used.

25,

pedestals

325A and 325B are arranged below the apparatus frame 321 so as to sandwich the transfer roll 323 in the apparatus horizontal direction (X direction).

Stage bases

326A and 326B are attached to the upper portions of the

bases

325A and 325B through the

guide rails

327A and 327B, respectively, so as to be movable in the apparatus front-rear direction (Y direction).

Stages

328A and 328B are attached to the upper portions of the

stage bases

326A and 326B so as to be movable in the left-right direction (X direction) of the apparatus via

guide rails

329A and 329B, respectively.

A light guide plate 307 is placed (supported) on the upper surfaces of the

stages

328A and 328B. Light guide plates 307 of various sizes can be placed on the top surfaces of the

stages

328A and 328B in a vertically or horizontally placed state (see FIG. 24). The vertical placement is such that the longitudinal direction of the light guide plate 307 is matched with the Y direction. The horizontal placement is such that the longitudinal direction of the light guide plate 307 is aligned with the X direction. The light guide plate 307 placed on the upper surfaces of the

stages

328A and 328B is positioned by positioning means not described in detail. The light guide plate 307 placed on the upper surfaces of the

stages

328A and 328B is pressed against the

stages

328A and 328B by the

clamp plates

318A and 318B (see FIG. 29).

Press cylinders

330A and 330B for moving the

stages

328A and 328B in the X direction are attached to the upper portions of the

stage bases

326A and 326B, respectively (see FIG. 25). The

pressure cylinders

330A and 330B are pressure applying means for applying pressure to the

stages

328A and 328B so as to press the light incident end surface 307a of the light guide plate 307 placed on the

stages

328A and 328B against the transfer surface 323a of the transfer roll 323. Is configured.

Further, as shown in FIGS. 25 to 28, the optical sheet processing apparatus 320 is disposed so as to sandwich the transfer roll 323 in an oblique direction with respect to the X direction and the Y direction corresponding to the

stages

328A and 328B. Serving

motors

331A and 331B are provided. Pinion gears 332A and 332B are attached to the output shafts 331a of the forming

servomotors

331A and 331B, respectively. Rack gears 333A and 333B extending in the Y direction and meshing with the pinion gears 332A and 332B are provided on inner side surfaces of the lower portions of the

stage bases

326A and 326B, respectively. Accordingly, when the forming

servomotors

331A and 331B are driven to rotate, the rotation of the forming

servomotors

331A and 331B is transmitted to the

stage bases

326A and 326B via the pinion gears 332A and 332B and the rack gears 333A and 333B, and the stage base 326A. , 326B move in the Y direction, and accordingly, the

stages

328A, 328B move in the Y direction.

In the lower part of the rack 322,

shafts

334A and 334B extending in the vertical direction of the apparatus (Z direction) are rotatably supported. These

shafts

334A and 334B are arranged so as to sandwich the transfer roll 323 in the Y direction. Spur gears 335A and 335B that mesh with the above-described pinion gears 332A and 332B are provided in the middle portions of the

shafts

334A and 334B, respectively. In addition,

electromagnetic clutches

336A and 336B are attached to the upper ends of the

shafts

334A and 334B, respectively.

Although not specifically described, the

shafts

334A and 334B and the spur gears 335A and 335B have a rotary ball spline structure, and the

shafts

334A and 334B can move up and down with respect to the spur gears 335A and 335B. The rack 322 can be lifted and lowered by a lifting means, and the transfer roll 323 can be lifted and lowered accordingly.

The support plate 322a is connected to the rack 322.

Shafts

337A and 337B extending downward are respectively rotatably supported at portions of the support plate 322a corresponding to the

shafts

334A and 334B. Spur gears 338A and 338B are provided in the middle of the

shafts

337A and 337B, respectively. The lower ends of the

shafts

337A and 337B are attached to the

electromagnetic clutches

336A and 336B, respectively.

The electromagnetic clutch 336A interrupts the transmission of power from the spur gear 335A to the spur gear 338A by interrupting the connection between the

shafts

334A and 337A. Specifically, when the electromagnetic clutch 336A is ON, the

shafts

334A and 337A are connected to each other, and when the electromagnetic clutch 336A is OFF, the connections between the

shafts

334A and 337A are released. The electromagnetic clutch 336B interrupts transmission of power from the spur gear 335B to the spur gear 338B by intermittently connecting the

shafts

334B and 337B. Specifically, when the electromagnetic clutch 336B is ON, the

shafts

334B and 337B are connected to each other, and when the electromagnetic clutch 336B is OFF, the connections between the

shafts

334B and 337B are released.

The roll shaft 323 b of the transfer roll 323 extends below the rack 322. A spur gear 339 that meshes with the spur gears 338A and 338B is attached to the lower end of the roll shaft 323b.

When the forming servomotor 331A is driven to rotate with the electromagnetic clutch 336A turned on, transfer is performed via the pinion gear 332A, spur gear 335A, shaft 334A, electromagnetic clutch 336A, shaft 337A, spur gear 338A, and spur gear 339. The roll 323 rotates. Further, when the forming servo motor 331B is driven to rotate with the electromagnetic clutch 336B turned on, the pinion gear 332B, the spur gear 335B, the shaft 334B, the electromagnetic clutch 336B, the shaft 337B, the spur gear 338B, and the spur gear 339 are driven. As a result, the transfer roll 323 rotates. Accordingly, the stage 328A can be moved and the transfer roll 323 can be rotated by the forming servo motor 331A, and the stage 328B can be moved and the transfer roll 323 can be rotated by the forming servo motor 331B.

In the above, the pinion gears 332A and 332B, the

shafts

334A and 334B, the spur gears 335A and 335B, the

electromagnetic clutches

336A and 336B, the

shafts

337A and 337B, the spur gears 338A and 338B, and the spur gear 339 are formed by the forming

servomotors

331A and 331B. A rotational power transmission mechanism that transmits the driving force to the transfer roll 323 is configured. The forming

servomotors

331A and 331B and the rotating power transmission mechanism constitute rotating means for rotating the transfer roll 323.

The pinion gears 332A and 332B, the rack gears 333A and 333B, the

stage bases

326A and 326B, and the

guide rails

327A and 327B provide a moving power transmission mechanism that transmits the driving force of the forming

servomotors

331A and 331B to the

stages

328A and 328B. It is composed. The forming

servomotors

331A and 331B and the moving power transmission mechanism constitute moving means for moving the

stages

328A and 328B in the forming direction of the uneven portion 309 with respect to the transfer roll 323.

Next, a forming process for forming the uneven portion 309 on the light incident end face 307a of the light guide plate 307 using the optical sheet processing apparatus 320 configured as described above will be described with reference to FIG. In the main forming process, two workers are arranged on the front side and the rear side of the optical sheet processing apparatus 320. That is, work is performed by a total of four workers. At this time, the transfer roll 323 is heated to a certain temperature (for example, 100 ° C. to 200 ° C.) by the induction coil 341 and the power supply unit 342.

First, in the state where both the stage 328A on which the molded light guide plate 307 is placed and the stage 328B on which the light guide plate 307 before molding is placed are located on the front side of the optical sheet processing apparatus 320, the molding servo motor 331B is used. Is rotated in a predetermined direction to turn on the electromagnetic clutch 336B. Note that the driving of the molding servo motor 331A is stopped, and the electromagnetic clutch 336A is OFF.

Then, as shown in FIG. 30A, the stage 328B moves to the rear side while the transfer roll 323 rotates counterclockwise. At this time, a constant pressure (for example, 0.05 MPa to 50 MPa) is applied to the stage 328B so that the light incident end surface 307a of the light guide plate 307 placed on the stage 328B is pressed against the transfer surface 323a of the transfer roll 323 by the pressing cylinder 330B. Is applied. As a result, the transfer uneven portion 319 of the transfer roll 323 is transferred to the light incident end surface 307a of the light guide plate 307 placed on the stage 328B. While the light guide plate 307 placed on the stage 328B is being molded as described above, the molded light guide plate 307 is taken out from the stage 328A.

Next, the drive of the molding servo motor 331B is stopped, and the electromagnetic clutch 335B is turned OFF. Then, as shown in FIG. 30B, the rotation of the transfer roll 323 stops, and the stage 328B on which the molded light guide plate 307 is placed stops on the rear side of the optical sheet processing apparatus 320. Meanwhile, a new light guide plate 307 is placed and placed on the stage 328A.

Next, the stage 328A on which the new light guide plate 307 is placed is located on the front side of the optical sheet processing apparatus 320, and the stage 328B on which the molded light guide plate 307 is placed is located on the rear side of the optical sheet processing apparatus 320. In this state, the molding servo motor 331A is rotationally driven in a predetermined direction, and the electromagnetic clutch 336A is turned on.

Then, as shown in FIG. 30C, the stage 328A moves to the rear side while the transfer roll 323 rotates in the clockwise direction. At this time, a constant pressure is applied to the stage 328A by the pressing cylinder 330A so that the light incident end surface 307a of the light guide plate 307 placed on the stage 328A is pressed against the transfer surface 323a of the transfer roll 323. As a result, the transfer uneven portion 319 of the transfer roll 323 is transferred to the light incident end surface 307a of the light guide plate 307 placed on the stage 328A. While the light guide plate 307 placed on the stage 328A is being molded in this way, the molded light guide plate 307 is taken out from the stage 328B.

Next, the drive of the molding servo motor 331A is stopped, and the electromagnetic clutch 336A is turned OFF. Then, as shown in FIG. 30D, the rotation of the transfer roll 323 stops, and the stage 328A on which the molded light guide plate 307 is placed stops on the rear side of the optical sheet processing apparatus 320. Meanwhile, a new light guide plate 307 is placed and placed on the stage 328B.

Next, in a state where both the stage 328A on which the molded light guide plate 307 is placed and the stage 328B on which the new light guide plate 307 is placed are positioned on the rear side of the optical sheet processing apparatus 320, the molding servo motor 331B is used. Is rotated in the opposite direction to turn on the electromagnetic clutch 336B.

Then, as shown in FIG. 30E, the stage 328B moves forward while the transfer roll 323 rotates clockwise. At this time, a constant pressure is applied to the stage 328B by the pressing cylinder 330B so that the light incident end surface 307a of the light guide plate 307 placed on the stage 328B is pressed against the transfer surface 323a of the transfer roll 323. As a result, the transfer uneven portion 319 of the transfer roll 323 is transferred to the light incident end surface 307a of the light guide plate 307 placed on the stage 328B. While the light guide plate 307 placed on the stage 328B is being molded as described above, the molded light guide plate 307 is taken out from the stage 328A.

Next, the drive of the molding servo motor 331B is stopped, and the electromagnetic clutch 336B is turned OFF. Then, as shown in FIG. 30F, the rotation of the transfer roll 323 stops and the stage 328B on which the molded light guide plate 307 is placed stops on the front side of the optical sheet processing apparatus 320. Meanwhile, a new light guide plate 307 is placed and placed on the stage 328A.

Next, the stage 328A on which the new light guide plate 307 is placed is located on the rear side of the optical sheet processing apparatus 320, and the stage 328B on which the molded light guide plate 307 is placed is located on the front side of the optical sheet processing apparatus 320. In this state, the molding servo motor 331A is rotated in the opposite direction, and the electromagnetic clutch 336A is turned on.

Then, although illustration is omitted, the stage 328A moves to the front side while the transfer roll 323 rotates counterclockwise. At this time, a constant pressure is applied to the stage 328A by the pressing cylinder 330A so that the light incident end surface 307a of the light guide plate 307 placed on the stage 328A is pressed against the transfer surface 323a of the transfer roll 323. As a result, the transfer uneven portion 319 of the transfer roll 323 is transferred to the light incident end surface 307a of the light guide plate 307 placed on the stage 328A. While the light guide plate 307 placed on the stage 328A is being molded in this way, the molded light guide plate 307 is taken out from the stage 328B.

Next, when the drive of the forming servo motor 331A is stopped and the electromagnetic clutch 336A is turned OFF, the rotation of the transfer roll 323 is stopped, and the stage 328A on which the formed light guide plate 307 is mounted is provided on the optical sheet processing apparatus 320. Stop at the front side. Meanwhile, a new light guide plate 307 is placed and placed on the stage 328B.

As described above, in the main forming step, while the molded light guide plate 307 placed on the stage 328A is taken out and a new light guide plate 307 is placed on the stage 328A, the light guide plate 307 is placed on the stage 328B. An uneven portion 309 is formed on the light incident end face 307a of the placed light guide plate 307, the molded light guide plate 307 placed on the stage 328B is taken out, and a new light guide plate 307 is placed on the stage 328B. During the process, the uneven portion 309 can be formed on the light incident end face 307a of the light guide plate 307 placed on the stage 328A. In the main forming step, any light guide plate 307 placed on the

stages

328A and 328B can be formed from both the front and rear directions.

Another molding process for forming the uneven portion 309 on the light incident end surface 307a of the light guide plate 307 using the optical sheet processing apparatus 320 will be described with reference to FIG. In the main forming step, one worker is arranged on each of the front side and the rear side of the optical sheet processing apparatus 320. That is, work is performed by a total of two workers. At this time, the transfer roll 323 is heated to a constant temperature by the induction coil 341 and the power supply unit 342.

First, the stage 328A on which the molded light guide plate 307 is placed is located on the rear side of the optical sheet processing apparatus 320, and the stage 328B on which the light guide plate 307 before molding is placed is located on the front side of the optical sheet processing apparatus 320. In this state, the molding servo motor 331B is rotated in a predetermined direction to turn on the electromagnetic clutch 336B. Note that the driving of the molding servo motor 331A is stopped, and the electromagnetic clutch 336A is OFF.

Then, as shown in FIG. 31A, the stage 328B moves to the rear side while the transfer roll 323 rotates counterclockwise. At this time, a constant pressure is applied to the stage 328B by the pressing cylinder 330B so that the light incident end surface 307a of the light guide plate 307 placed on the stage 328B is pressed against the transfer surface 323a of the transfer roll 323. As a result, the transfer uneven portion 319 of the transfer roll 323 is transferred to the light incident end surface 307a of the light guide plate 307 placed on the stage 328B. While the light guide plate 307 placed on the stage 328B is being molded as described above, the molded light guide plate 307 is taken out from the stage 328A.

Next, the drive of the molding servo motor 331B is stopped, and the electromagnetic clutch 336B is turned OFF. Then, as shown in FIG. 31B, the rotation of the transfer roll 323 stops, and the stage 328B on which the molded light guide plate 307 is placed stops at the rear side of the optical sheet processing apparatus 320. Meanwhile, a new light guide plate 307 is placed and placed on the stage 328A.

Next, the electromagnetic clutch 336B is turned off with the stage 328A on which the new light guide plate 307 is placed and the stage 328B on which the molded light guide plate 307 is placed positioned on the rear side of the optical sheet processing apparatus 320. The molding servo motor 331B is rotationally driven in the opposite direction. Then, as shown in FIG. 31C, the stage 328B on which the molded light guide plate 307 is mounted moves to the front side while the rotation of the transfer roll 323 is stopped. At this time, no pressure is applied to the stage 328B by the pressing cylinder 330B. When the stage 328B returns to the original position, the molding servo motor 331B is stopped. Meanwhile, the stage 328A on which the new light guide plate 307 is placed stands by at the same position.

Next, the stage 328A on which the new light guide plate 307 is placed is located on the rear side of the optical sheet processing apparatus 320, and the stage 328B on which the molded light guide plate 307 is placed is located on the front side of the optical sheet processing apparatus 320. In this state, the molding servo motor 331A is rotationally driven in a predetermined direction, and the electromagnetic clutch 336A is turned on.

Then, as shown in FIG. 31D, the stage 328A moves to the front side while the transfer roll 323 rotates counterclockwise. At this time, a constant pressure is applied to the stage 328A by the pressing cylinder 330A so that the light incident end surface 307a of the light guide plate 307 placed on the stage 328A is pressed against the transfer surface 323a of the transfer roll 323. As a result, the transfer uneven portion 319 of the transfer roll 323 is transferred to the light incident end surface 307a of the light guide plate 307 placed on the stage 328A. While the light guide plate 307 placed on the stage 328A is being molded in this way, the molded light guide plate 307 is taken out from the stage 328B.

Next, the drive of the molding servo motor 331A is stopped, and the electromagnetic clutch 336A is turned OFF. Then, as shown in FIG. 31E, the rotation of the transfer roll 323 stops, and the stage 328A on which the molded light guide plate 307 is placed stops at the front side of the optical sheet processing apparatus 320. Meanwhile, a new light guide plate 307 is placed and placed on the stage 328B.

Next, the electromagnetic clutch 336A is turned OFF in a state where the stage 328A on which the molded light guide plate 307 is placed and the stage 328B on which the new light guide plate 307 is placed are located on the front side of the optical sheet processing apparatus 320. As it is, the molding servomotor 331A is rotated in the opposite direction. Then, as shown in FIG. 31F, the stage 328A on which the molded light guide plate 307 is placed moves to the rear side while the rotation of the transfer roll 323 is stopped. At this time, no pressure is applied to the stage 328A by the pressing cylinder 330A. When the stage 328A returns to the original position, the molding servo motor 331A is stopped. Meanwhile, the stage 328B on which the new light guide plate 307 is placed stands by at the same position.

As described above, also in the main forming step, while the molded light guide plate 307 placed on the stage 328A is taken out and a new light guide plate 307 is placed on the stage 328A, the light guide plate 307 is placed on the stage 328B. An uneven portion 309 is formed on the light incident end face 307a of the placed light guide plate 307, the molded light guide plate 307 placed on the stage 328B is taken out, and a new light guide plate 307 is placed on the stage 328B. During the process, the uneven portion 309 can be formed on the light incident end face 307a of the light guide plate 307 placed on the stage 328A. In the main forming step, the light guide plate 307 can be formed by a minimum required number of workers.

Referring to FIG. 32, still another molding process for forming the uneven portion 309 on the light incident end surface 307a of the light guide plate 307 using the optical sheet processing apparatus 320 described above will be described. In the main forming step, two workers W are arranged on the front side of the optical sheet processing apparatus 320 (see FIG. 24). At this time, the transfer roll 323 is heated to a constant temperature by the induction coil 341 and the power supply unit 342.

Then, as shown in FIG. 32A, the stage 328B moves to the rear side while the transfer roll 323 rotates counterclockwise. At this time, a constant pressure is applied to the stage 328B by the pressing cylinder 330B so that the light incident end surface 307a of the light guide plate 307 placed on the stage 328B is pressed against the transfer surface 323a of the transfer roll 323. As a result, the transfer uneven portion 319 of the transfer roll 323 is transferred to the light incident end surface 307a of the light guide plate 307 placed on the stage 328B. While the light guide plate 307 placed on the stage 328B is being molded as described above, the molded light guide plate 307 is taken out from the stage 328A.

Next, the drive of the molding servo motor 331B is stopped, and the electromagnetic clutch 336B is turned OFF. Then, as shown in FIG. 32B, the rotation of the transfer roll 323 stops, and the stage 328B on which the molded light guide plate 307 is placed stops on the rear side of the optical sheet processing apparatus 320. Meanwhile, a new light guide plate 307 is placed and placed on the stage 328A.

Next, the stage 328A on which the new light guide plate 307 is placed is located on the front side of the optical sheet processing apparatus 320, and the stage 328B on which the molded light guide plate 307 is placed is located on the rear side of the optical sheet processing apparatus 320. In a state where the electromagnetic clutch 336B is OFF, the molding servo motor 331B is driven to rotate in the opposite direction. Then, as shown in FIG. 32C, the stage 328B on which the molded light guide plate 307 is mounted moves to the front side while the rotation of the transfer roll 323 is stopped. At this time, no pressure is applied to the stage 328B by the pressing cylinder 330B. Then, when the stage 328B returns to the original position, the driving of the molding servo motor 331B is stopped. Meanwhile, the stage 328A on which the new light guide plate 307 is placed stands by at the same position.

Next, in a state where both the stage 328A on which the new light guide plate 307 is placed and the stage 328B on which the molded light guide plate 307 is placed are positioned on the front side of the optical sheet processing apparatus 320, the forming servo motor 331A is operated. The electromagnetic clutch 336A is turned ON by rotating in a predetermined direction.

Then, as shown in FIG. 32 (d), the stage 328A moves to the rear side while the transfer roll 323 rotates clockwise. At this time, a constant pressure is applied to the stage 328A by the pressing cylinder 330A so that the light incident end surface 307a of the light guide plate 307 placed on the stage 328A is pressed against the transfer surface 323a of the transfer roll 323. As a result, the transfer uneven portion 319 of the transfer roll 323 is transferred to the light incident end surface 307a of the light guide plate 307 placed on the stage 328A. While the light guide plate 307 placed on the stage 328A is being molded in this way, the molded light guide plate 307 is taken out from the stage 328B.

Next, the drive of the molding servo motor 331A is stopped, and the electromagnetic clutch 336A is turned OFF. Then, as shown in FIG. 32E, the rotation of the transfer roll 323 stops and the stage 328A on which the molded light guide plate 307 is placed stops on the rear side of the optical sheet processing apparatus 320. Meanwhile, a new light guide plate 307 is placed and placed on the stage 328B.

Next, the stage 328A on which the molded light guide plate 307 is placed is located on the rear side of the optical sheet processing apparatus 320, and the stage 328B on which the new light guide plate 307 is placed is located on the front side of the optical sheet processing apparatus 320. In the state where the electromagnetic clutch 336A is OFF, the molding servo motor 331A is driven to rotate in the opposite direction.

Then, as shown in FIG. 32 (f), the stage 328A on which the molded light guide plate 307 is placed moves to the front side while the rotation of the transfer roll 323 is stopped. At this time, no pressure is applied to the stage 328A by the pressing cylinder 330A. When the stage 328A returns to the original position, the driving of the molding servo motor 331A is stopped. Meanwhile, the stage 328B on which the new light guide plate 307 is placed stands by at the same position.

As described above, also in the main forming step, while the molded light guide plate 307 placed on the stage 328A is taken out and a new light guide plate 307 is placed on the stage 328A, the light guide plate 307 is placed on the stage 328B. An uneven portion 309 is formed on the light incident end face 307a of the placed light guide plate 307, the molded light guide plate 307 placed on the stage 328B is taken out, and a new light guide plate 307 is placed on the stage 328B. During the process, the uneven portion 309 can be formed on the light incident end face 307a of the light guide plate 307 placed on the stage 328A. Further, in this molding process, even if there is a layout problem such as a wall on the rear side of the optical sheet processing apparatus 320, the molding work of the light guide plate 307 is performed by a minimum required number of workers. Can do.

Note that the moving speed of the

stages

328A and 328B is not necessarily constant. For example, when a plurality of LEDs 306 are arranged facing the light incident end surface 307 a of the light guide plate 307, the uneven portion 309 may be formed only on the light incident end surface 307 a around the LED 306. For this reason, when the transfer surface 323a of the transfer roll 323 and the light incident end surface 307a of the light guide plate 307 are pressed against each other, when the light incident end surface 307a at the position facing the LED 306 and the transfer surface 323a are in contact with each other, a desired uneven portion 309 is formed. When the

stages

328A and 328B are moved at the obtained transfer (molding) speed and the other light incident end surface 307a and the transfer surface 323a are in contact with each other, the

stages

328A and 328B may be moved at a higher speed. Thereby, the processing tact of the light guide plate 307 can be improved. The light incident end face 307 a around the LED 306 indicates +1 mm from the width size of the LED 306 in the direction orthogonal to the thickness direction of the light guide plate 307.

As described above, in the present embodiment, the transfer roll 323 is heated and the transfer surface 323a of the transfer roll 323 and the light incident end surface 307a of the light guide plate 307 are pressed against each other to be provided on the transfer surface 323a of the transfer roll 323. The uneven portion 319 for transfer is thermally transferred to the light incident end surface 307a of the light guide plate 307 so that the uneven portion 309 is formed on the light incident end surface 307a of the light guide plate 307. As in the case where the uneven portion 309 is formed on the light incident end surface 307a of the light guide plate 307, no chips are generated. Accordingly, the chips are not attached to or mixed into the light guide plate 307, so that the quality of the product can be stabilized.

By the way, when there is only one stage on which the light guide plate 307 is placed, the molding process of the light guide plate 307 is not interrupted during the period during which the light guide plate 307 is placed on the stage and during the period during which the light guide plate 307 is removed from the stage. I do not get. Accordingly, the tact of the light guide plate 307 is reduced.

On the other hand, in the present embodiment, the two

stages

328A and 328B on which the light guide plate 307 is placed are arranged so as to sandwich the transfer roll 323, and the light guide plate 307 placed on the stage 328A is not molded. The light guide plate 307 placed on the stage 328B is molded during the period, and the light guide plate 307 placed over the stage 328B is not molded during the period. Make the molding process. Since the light guide plate 307 is molded from both the left and right sides of the transfer roll 323 in this way, the light guide plate 307 is placed in a period during which the light guide plate 307 is inserted into the

stages

328A and 328B and during which the light guide plate 307 is removed from the

stages

328A and 328B. There is no need to interrupt the molding process. Thereby, the forming tact of the light guide plate 307 can be increased, and the productivity can be improved.

Note that the present invention is not limited to the above embodiment. For example, the mechanism for rotating the transfer roll 323 and moving the

stages

328A and 328B in the front-rear direction (Y direction) of the apparatus is not limited to the above-described one. For example, if there is no need to raise and lower the transfer roll 323, FIG. The structure shown in FIG. In the structure shown in FIG. 33, the electromagnetic clutch 336A intermittently connects the output shaft 331a of the forming servomotor 331A and the shaft 337A fixed to the spur gear 338A. Further, the electromagnetic clutch 336B intermittently connects the output shaft 331a of the forming servomotor 331B and the shaft 337B fixed to the spur gear 338B.

Further, as a mechanism for rotating the transfer roll 323, for example, a belt and a pulley may be used in addition to the meshing of the spur gears.

In the above-described embodiment, the transfer roll 323 is rotated by the forming

servo motors

331A and 331B and the

stages

328A and 328B are moved in the Y direction. However, the present invention is not limited to this, and means for rotating the transfer roll 323 is not limited thereto. Further, as means for moving the

stages

328A and 328B, different motors may be used, and the respective motors may be driven synchronously.

Here, when the light guide plate 307 and the transfer roll 323 come into contact with each other, if there is a large difference between the rotation speed of the transfer roll 323 and the movement speed of the

stages

328A and 328B, the appearance of the light guide plate 307 deteriorates. To do. For this reason, when the motor dedicated to the roll for rotating the transfer roll 323 is not installed, the diameter management of the transfer roll 323 is important. On the other hand, when a dedicated motor for rotating the transfer roll 323 is installed, the rotation speed of the motor can be adjusted in accordance with the diameter of the transfer roll 323, so that the appearance defect of the light guide plate 307 is generated. Can be prevented.

Further, in the above embodiment, the light guide plate 307 supported on the other of the

stages

328A and 328B is formed while the light guide plate 307 supported on one of the

stages

328A and 328B is not formed. However, if possible, the light guide plates 307 supported by the

stages

328A and 328B may be simultaneously molded.

In the above embodiment, one light guide plate 307 is supported on the

stages

328A and 328B. However, the number of light guide plates 307 supported on the

stages

328A and 328B is not limited to one, and a plurality of light guide plates 307 are supported. There may be.

Furthermore, although the said embodiment forms the uneven | corrugated | grooved part 309 in the light-incidence end surface 307a of the light-guide plate 307 comprised in the backlight unit 303 of the liquid crystal display device 301 used for a liquid crystal television, the optical of this invention The sheet processing apparatus and method can be applied to, for example, an optical sheet forming process as a light guide plate for illumination or decoration.

FIG. 34 is a schematic cross-sectional view showing a liquid crystal display device including a light guide plate which is an optical sheet obtained by one embodiment of the optical sheet processing apparatus according to the present invention. In the figure, a liquid crystal display device 401 according to this embodiment is used for a liquid crystal television, for example. The liquid crystal display device 401 includes a liquid crystal panel 402 and an edge type backlight unit 403 disposed on the back side of the liquid crystal panel 402. The thickness of the liquid crystal panel 402 is about 1.8 mm, for example.

The backlight unit 403 has a box-shaped metal backlight housing 404. A plurality of electronic components 405 are provided on the back surface (back surface) of the backlight housing 404 via a substrate (not shown). A plurality of LEDs 406 for irradiating light are attached to the inner wall surfaces of the backlight housing 404 facing each other.

In the backlight housing 404, a light guide plate 407 having a rectangular cross section for guiding the light emitted from the LED 406 to the liquid crystal panel 402 is accommodated via a reflection sheet 408. As shown in FIG. 35, the light incident end surface 407a of the light guide plate 407 is provided with an uneven portion 409 having a substantially corrugated cross section. The thickness of the light guide plate 407 is 3 mm, for example.

The light guide plate 407 is made of a thermoplastic resin. Specifically, the light guide plate 407 is made of an amorphous resin having high dimensional accuracy, impact strength, and transparency. Examples of the amorphous resin include polymethyl methacrylate resin (PMMA), polystyrene (PS), polycarbonate (PC), and cycloolefin polymer (COP). Although not shown in particular, a protective masking film is preferably bonded to the main surface of one or both sides of the light guide plate 407.

The masking film is attached to prevent the main surface of the light guide plate 407 from being damaged. The masking film has a base material and an adhesive layer that is a paste component formed on the base material. The adhesive layer is disposed between the base material and the light guide plate 407. The base material is made of, for example, a polyolefin (PO) resin such as a polypropylene (PP) resin or a polyethylene (PE) resin, a polyethylene terephthalate (PET) resin, or the like. The adhesive layer is formed of, for example, a polyolefin (PO) elastomer, an ethylene / vinyl acetate copolymer (EVA), or the like. The thickness of the masking film is, for example, 40 μm to 90 μm.

The light emitted from the LED 406 is incident on the light incident end surface 407a of the light guide plate 407. The back surface of the light guide plate 407 is a reflective surface that reflects the light emitted from the LED 406, and the front surface of the light guide plate 407 is a light output surface that emits the light emitted from the LED 406 and the light reflected by the reflective surface. It has become. The back surface (reflection surface) of the light guide plate 407 has a structure that easily reflects and scatters light, such as dot pattern printing with ink.

On the front side of the light guide plate 407, an optical film group 410 formed by laminating a plurality (three in this case) of optical films is disposed. The thickness of the optical film group 410 is, for example, about 0.2 mm. Edge portions of the light guide plate 407 and the optical film group 410 are fixed to the backlight housing 404 by a frame body 411 made of resin (for example, PC). The liquid crystal panel 402 is fixed to the backlight unit 403 by a metal frame body 412.

FIG. 36 is a flowchart showing a process for manufacturing the light guide plate 407 described above. In the figure, first, a light guide plate original plate is produced by a melt extrusion sheet forming process or the like (step S401). Subsequently, the light guide plate original plate is roughly cut and cut using a panel saw, a running saw, or the like to obtain the light guide plate 407 (step S402). Subsequently, using a mirror surface processing machine, the light incident end surface 407a of the light guide plate 407 is subjected to mirror surface processing (step S403). Then, the uneven | corrugated | grooved part 409 is formed in the light-incidence end surface 407a by performing a thermal transfer process to the light-incidence end surface 407a of the light-guide plate 407 (step S404). Note that step S403 is not necessarily performed.

FIG. 37 is a plan view showing an embodiment of an optical sheet processing apparatus according to the present invention. 38 is a front view of the optical sheet processing apparatus shown in FIG. 37, FIG. 39 is a sectional view taken along the line VI-VI in FIG. 38, and FIG. 40 is an enlarged view of the relevant part in FIG. 41 is an enlarged sectional view taken along the line VIII-VIII in FIG. FIG. 42 is a perspective view schematically showing the optical sheet processing apparatus shown in FIG. In each figure, the optical sheet processing apparatus 20 of the present embodiment is used when performing Step S404 shown in FIG.

The optical sheet processing apparatus 420 includes an apparatus frame 421. A rack 422 is disposed at the center of the apparatus frame 421, and a metal transfer roll 423 is rotatably supported on the rack 422 (see FIG. 39). As shown in FIG. 42, a transfer uneven portion 419 is formed on the outer peripheral surface 423 a of the transfer roll 423 along the circumferential direction of the transfer roll 423. The outer peripheral surface 423a of the transfer roll 423 serves as a transfer surface for providing an uneven portion on the light incident end surface 407a of the light guide plate 407. The transfer concavo-convex portion 419 is formed in a prism shape or a lenticular shape with respect to the roll axis direction of the transfer roll 423, for example.

As shown in FIG. 39, the transfer roll 423 is an electric heater roll in which an induction coil 441 is incorporated. A power supply unit 442 that supplies high-frequency current to the induction coil 441 is disposed above the transfer roll 423. The induction coil 441 and the power source unit 442 constitute a heating unit that heats the transfer roll 423. When a high-frequency current flows through the induction coil 441, an eddy current is generated in the transfer roll 423 by the magnetic field generated in the induction coil 441, and the transfer roll 423 generates heat.

38,

pedestals

425A and 425B are arranged below the apparatus frame 421 so as to sandwich the transfer roll 423 in the apparatus left-right direction (X direction).

Stage bases

426A and 426B are attached to the upper portions of the

bases

425A and 425B via

guide rails

427A and 427B, respectively, so as to be movable in the apparatus front-rear direction (Y direction).

Stages

428A and 428B are attached to the upper portions of the

stage bases

426A and 426B via

guide rails

429A and 429B so as to be movable in the left-right direction (X direction) of the apparatus.

A light guide plate 407 is placed (supported) on the upper surfaces of the

stages

428A and 428B. A variety of sizes of light guide plates 407 can be placed vertically or horizontally on the top surfaces of the

stages

428A and 428B (see FIG. 37). The vertical placement is such that the longitudinal direction of the light guide plate 407 is matched with the Y direction. The horizontal placement is such that the longitudinal direction of the light guide plate 407 matches the X direction. The light guide plate 407 placed on the upper surfaces of the

stages

428A and 428B is positioned by positioning means not described in detail. The light guide plate 407 placed on the upper surfaces of the

stages

428A and 428B is pressed against the

stages

428A and 428B by the

clamp plates

418A and 418B (see FIG. 42).

Press cylinders

430A and 430B for moving the

stages

428A and 428B in the X direction are respectively attached to the upper portions of the

stage bases

426A and 426B (see FIG. 38). The

pressure cylinders

430A and 430B are pressure applying means for applying pressure to the

stages

428A and 428B so as to press the light incident end surface 407a of the light guide plate 407 mounted on the

stages

428A and 428B against the transfer surface 423a of the transfer roll 423. Is configured.

Further, as shown in FIGS. 38 to 41, the optical sheet processing apparatus 420 is disposed so as to sandwich the transfer roll 423 in an oblique direction with respect to the X direction and the Y direction corresponding to the

stages

428A and 428B. Serving

motors

431A and 431B are provided. Pinion gears 432A and 432B are attached to the output shafts 431a of the forming

servomotors

431A and 431B, respectively. Rack gears 433A and 433B extending in the Y direction and meshing with the pinion gears 432A and 432B are provided on the inner side surfaces of the lower portions of the

stage bases

426A and 426B, respectively. Accordingly, when the forming

servo motors

431A and 431B are driven to rotate, the rotation of the forming

servo motors

431A and 431B is transmitted to the

stage bases

426A and 426B via the pinion gears 432A and 432B and the rack gears 433A and 433B, and the stage base 426A. , 426B move in the Y direction, and accordingly, the

stages

428A, 428B move in the Y direction.

In the lower part of the rack 422,

shafts

434A and 434B extending in the Z direction are rotatably supported. These

shafts

434A and 434B are arranged so as to sandwich the transfer roll 423 in the Y direction. Spur gears 435A and 435B that mesh with the above-described pinion gears 432A and 432B are provided in the middle portions of the

shafts

434A and 434B, respectively. The

shafts

434A and 434B and the spur gears 435A and 435B have a rotary ball spline structure. Further,

electromagnetic clutches

436A and 436B are attached to the upper ends of the

shafts

434A and 434B, respectively.

The support plate 422a is connected to the rack 422.

Shafts

437A and 437B extending downward are rotatably supported at portions of the support plate 422a corresponding to the

shafts

434A and 434B. Spur gears 438A and 438B are provided in the middle of the

shafts

437A and 437B, respectively. The lower ends of the

shafts

437A and 437B are attached to the

electromagnetic clutches

436A and 436B, respectively.

The electromagnetic clutch 436A interrupts transmission of power from the spur gear 435A to the spur gear 438A by intermittently connecting the

shafts

434A and 437A. Specifically, when the electromagnetic clutch 436A is ON, the

shafts

434A and 437A are connected to each other, and when the electromagnetic clutch 436A is OFF, the connections between the

shafts

434A and 437A are released. The electromagnetic clutch 436B interrupts transmission of power from the spur gear 435B to the spur gear 438B by intermittently connecting the

shafts

434B and 437B. Specifically, when the electromagnetic clutch 436B is ON, the

shafts

434B and 437B are connected to each other, and when the electromagnetic clutch 436B is OFF, the connection between the

shafts

434B and 437B is released.

The roll shaft 423 b of the transfer roll 423 extends below the rack 422. Spur gears 439 that mesh with the spur gears 438A and 438B are attached to the lower end of the roll shaft 423b.

A ball screw 443 extending in the vertical direction of the apparatus (Z direction) is disposed on the rear side of the optical sheet processing apparatus 420. The ball screw 443 includes a screw shaft 443a and a nut 443b that meshes with the screw shaft 443a. A main elevating body 444 is attached to the nut 443b. The main elevating body 444 is fixed to one side surface of the rack 422. The screw shaft 443a is rotated by the lifting servo motor 445. Linear guides 446 extending in the Z direction are respectively disposed on both front and rear sides of the rack 422. A plurality of auxiliary lifting bodies 447 that are slidable along the linear guide 446 are fixed to the side surfaces on both sides of the rack 422. When the screw shaft 443a of the ball screw 443 is rotated by the lifting / lowering servo motor 445, the main lifting / lowering body 444 and the auxiliary lifting / lowering bodies 447 move in the Z direction, and the rack 422 is lifted and lowered and supported by the rack 422. The transfer roll 423 moves up and down.

In the above, the

servo motors

431A and 431B, the pinion gears 432A and 432B, the

shafts

434A and 434B, the spur gears 435A and 435B, the

electromagnetic clutches

436A and 436B, the

shafts

437A and 437B, the spur gears 438A and 438B, and the spur gear 439 are Rotating means for rotating the transfer roll 423 is configured.

Servo motors

431A and 431B, pinion gears 432A and 432B, rack gears 433A and 433B,

stage bases

426A and 426B, and

guide rails

427A and 427B move the

stages

428A and 428B in the direction in which the concavo-convex portion 409 is formed with respect to the transfer roll 423. The 1st moving means to move relatively is comprised.

Further, the rack 422, the ball screw 443, the main elevating body 444, the elevating servo motor 445, the linear guide 446, and the auxiliary elevating bodies 447 make the transfer roll 423 relative to the

stages

428A and 428B in the roll axis direction of the transfer roll 423. The second moving means for moving the image automatically is configured.

When the forming servo motor 431A is driven to rotate with the electromagnetic clutch 436A turned ON, transfer is performed via the pinion gear 432A, the spur gear 435A, the shaft 434A, the electromagnetic clutch 436A, the shaft 437A, the spur gear 438A, and the spur gear 439. The roll 423 rotates. Further, when the forming servo motor 431B is rotated with the electromagnetic clutch 436B turned on, the pinion gear 432B, the spur gear 435B, the shaft 434B, the electromagnetic clutch 436B, the shaft 437B, the spur gear 438B, and the spur gear 439 are used. As a result, the transfer roll 423 rotates. Accordingly, the stage 428A can be moved by the molding servo motor 431A and the transfer roll 423 can be rotated, and the stage 428B can be moved by the molding servo motor 431B and the transfer roll 423 can be rotated.

Here, the

shafts

434A and 434B and the spur gears 435A and 435B have a rotary ball spline structure as described above. That is, the

shafts

434A and 434B can move up and down relatively with respect to the spur gears 435A and 435B. Therefore, by rotating the screw shaft 443a of the ball screw 443 by the lifting servo motor 445, as shown in FIG. 43, when the transfer roll 423 is lifted, the spur gears 435A and 435B are not always lifted and always have the same height. The

shafts

434A and 434B, the electromagnetic clutches 4436A and 436B, the

shafts

437A and 437B, the spur gears 438A and 438B, and the spur gear 439 are lifted together with the rack 422.

Next, an example of a forming process for forming the uneven portion 409 on the light incident end surface 407a of the light guide plate 407 using the optical sheet processing apparatus 420 configured as described above will be described with reference to FIG. In the main forming step, two workers W are arranged on the front side of the optical sheet processing apparatus 420 (see FIG. 37). At this time, the transfer roll 423 is heated to a constant temperature (for example, 100 ° C. to 200 ° C.) by the induction coil 441 and the power supply unit 442.

First, in the state where both the stage 428A on which the molded light guide plate 407 is mounted and the stage 428B on which the unformed light guide plate 407 is mounted are positioned on the front side of the optical sheet processing apparatus 420, the molding servo motor 431B. Is rotated in a predetermined direction to turn on the electromagnetic clutch 436B. Note that the drive of the molding servo motor 431A is stopped, and the electromagnetic clutch 436A is OFF.

Then, as shown in FIG. 44A, the stage 428B moves to the rear side while the transfer roll 423 rotates counterclockwise. At this time, a constant pressure (for example, 0.05 MPa to 50 MPa) is applied to the stage 428B so that the light incident end surface 407a of the light guide plate 407 placed on the stage 428B is pressed against the transfer surface 423a of the transfer roll 423 by the pressing cylinder 430B. Is applied. As a result, the uneven portion for transfer 419 of the transfer roll 423 is transferred to the light incident end surface 407a of the light guide plate 407 placed on the stage 428B. While the light guide plate 407 placed on the stage 428B is being molded in this way, the molded light guide plate 407 is taken out from the stage 428A.

Next, the drive of the molding servo motor 431B is stopped, and the electromagnetic clutch 436B is turned OFF. Then, as shown in FIG. 44B, the rotation of the transfer roll 423 stops, and the stage 428B on which the molded light guide plate 407 is placed stops on the rear side of the optical sheet processing apparatus 420. In the meantime, a new light guide plate 407 is placed and placed on the stage 428A.

Next, the stage 428A on which the new light guide plate 407 is placed is located on the front side of the optical sheet processing apparatus 420, and the stage 428B on which the molded light guide plate 407 is placed is located on the rear side of the optical sheet processing apparatus 420. In the state where the electromagnetic clutch 436B is OFF, the molding servo motor 431B is rotated in the opposite direction. Then, as shown in FIG. 44C, the stage 428B on which the molded light guide plate 407 is mounted moves to the front side while the rotation of the transfer roll 423 is stopped. At this time, no pressure is applied to the stage 428B by the pressing cylinder 430B. When the stage 428B returns to the original position, the drive of the molding servo motor 431B is stopped. Meanwhile, the stage 428A on which the new light guide plate 407 is placed stands by at the same position.

Next, with the stage 428A on which the new light guide plate 407 is placed and the stage 428B on which the molded light guide plate 407 is placed positioned on the front side of the optical sheet processing apparatus 420, the molding servo motor 431A is The electromagnetic clutch 436A is turned on by rotating in a predetermined direction.

Then, as shown in FIG. 44 (d), the stage 428A moves to the rear side while the transfer roll 423 rotates in the clockwise direction. At this time, a constant pressure is applied to the stage 428A by the pressing cylinder 430A so that the light incident end surface 407a of the light guide plate 407 placed on the stage 428A is pressed against the transfer surface 423a of the transfer roll 423. As a result, the transfer uneven portion 419 of the transfer roll 423 is transferred to the light incident end surface 407a of the light guide plate 407 placed on the stage 428A. Thus, while the light guide plate 407 placed on the stage 428A is being molded, the molded light guide plate 407 is taken out from the stage 428B.

Next, the driving of the molding servo motor 431A is stopped, and the electromagnetic clutch 436A is turned OFF. Then, as shown in FIG. 44E, the rotation of the transfer roll 423 stops, and the stage 428A on which the molded light guide plate 407 is placed stops on the rear side of the optical sheet processing apparatus 420. Meanwhile, a new light guide plate 407 is placed and placed on the stage 428B.

Next, the stage 428A on which the molded light guide plate 407 is placed is located on the rear side of the optical sheet processing apparatus 420, and the stage 428B on which the new light guide plate 407 is placed is located on the front side of the optical sheet processing apparatus 420. In the state where the electromagnetic clutch 436A is OFF, the molding servo motor 431A is rotated in the opposite direction.

Then, as shown in FIG. 44 (f), the stage 428A on which the molded light guide plate 407 is placed moves to the front side while the rotation of the transfer roll 423 is stopped. At this time, no pressure is applied to the stage 428A by the pressing cylinder 430A. When the stage 428A returns to the original position, the driving of the molding servo motor 431A is stopped. Meanwhile, the stage 428B on which the new light guide plate 407 is placed stands by at the same position.

As described above, in the main forming step, while the molded light guide plate 407 placed on the stage 428A is taken out and a new light guide plate 407 is put on the stage 428A, it is placed on the stage 428B. An uneven portion 409 is formed on the light incident end face 407a of the placed light guide plate 407, the molded light guide plate 407 placed on the stage 428B is taken out, and a new light guide plate 407 is placed on the stage 428B. During the process, an uneven portion 409 is formed on the light incident end surface 407a of the light guide plate 407 placed on the stage 428A.

At this time, the moving speed of the

stages

428A and 428B is not necessarily constant. For example, when a plurality of LEDs 406 are arranged facing the light incident end surface 407 a of the light guide plate 407, the uneven portion 409 may be formed only on the light incident end surface 407 a around the LED 406. Therefore, when the transfer surface 423a of the transfer roll 423 and the light incident end surface 407a of the light guide plate 407 are pressed against each other, when the light incident end surface 407a at the position facing the LED 406 and the transfer surface 423a are in contact with each other, a desired uneven portion 409 is formed. When the

stages

428A and 428B are moved at the obtained transfer (molding) speed and the other light incident end surface 407a and the transfer surface 423a are in contact with each other, the

stages

428A and 428B may be moved at a higher speed. Thereby, the processing tact of the light guide plate 407 can be improved. The light incident end surface 407 a around the LED 406 indicates +1 mm from the width size of the LED 406 in the direction orthogonal to the thickness direction of the light guide plate 407.

By the way, when the transfer uneven portion 419 provided on the transfer surface 423 a of the transfer roll 423 is thermally transferred to the light incident end surface 407 a of the light guide plate 407, the resin is thermally decomposed at the light guide plate 407, and the addition contained in the light guide plate 407. The additive may precipitate due to decomposition of the agent and adhere to the transfer surface 423a of the transfer roll 423. Moreover, when the masking film is bonded to the main surface of the light guide plate 407, the paste component used for bonding the masking film adheres to the transfer surface 423a of the transfer roll 423 by applying pressure during molding. Sometimes.

Therefore, after the molding process is performed, if foreign matters such as additives and glue components adhere to the transfer surface 423a of the transfer roll 423, the transfer roll 423 is moved up and down by the lifting servo motor 445, and the transfer roll 423 is moved up and down. The portion of the transfer surface 423a that comes into contact with the light incident end surface 407a of the light guide plate 407 is shifted, and the next molding step is performed using the clean transfer surface 423a to which no foreign matter is attached.

As described above, in the present embodiment, the transfer roll 423 is heated and the transfer surface 423a of the transfer roll 423 and the light incident end surface 407a of the light guide plate 407 are pressed against each other to be provided on the transfer surface 423a of the transfer roll 423. The uneven portion 419 for transfer is thermally transferred to the light incident end surface 407a of the light guide plate 407, so that the uneven portion 409 is formed on the light incident end surface 407a of the light guide plate 407. Chips are not generated unlike the case where the uneven portion 409 is formed on the light incident end surface 407a of the light guide plate 407. Accordingly, the chips are not attached to or mixed into the light guide plate 407, so that the quality of the product can be stabilized.

Further, in this embodiment, a means for moving the transfer roll 423 up and down with respect to the

stages

428A and 428B is provided, and when the transfer surface 423a of the transfer roll 423 is soiled, the soiled portion of the transfer surface 423a is removed from the light guide plate 407. Since the transfer roll 423 is moved up and down so as to avoid contact with the light incident end surface 407a, the molding process can be quickly continued using the clean transfer surface 423a. Thereby, the quality of the product can be further stabilized. Further, for example, it is not necessary to remove the transfer roll 423 and perform ultrasonic cleaning of the transfer roll 423, so that the labor of an operator can be saved.

At this time, the induction coil 441 is built in the transfer roll 423, and the transfer roll 423 is heated by passing an electric current through the induction coil 441. Therefore, when the transfer roll 423 is heated by adjusting the temperature with oil. In comparison, the temperature distribution in the roll axis direction of the transfer roll 423 can be made uniform. For example, when an oil heater roll having a diameter of 200 mm and a length of 300 mm is used, temperature unevenness of 3 ° C. to 5 ° C. occurs in the roll axis direction, but when using an electric heater roll of the same size, The temperature unevenness in the roll axis direction is within about ± 0.5 ° C. Accordingly, by moving the transfer roll 423 up and down, the transfer roll 423 with respect to the light incident end surface 407a of the light guide plate 407 can be changed even if the contact position of the transfer surface 423a of the transfer roll 423 with the light incident end surface 407a of the light guide plate 407 is changed. The transfer accuracy of the transfer concavo-convex portion 419 can be stabilized.

Note that the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the transfer roll 423 is moved up and down with respect to the

stages

428A and 428B. However, the transfer roll 423 is not particularly limited thereto, and the

stage

428A and 428B is moved up and down with respect to the transfer roll 423. The contact height position between the roll 423 and the light guide plate 407 may be changed.

In the above embodiment, the transfer roll 423 is rotated by meshing the spur gears. However, the mechanism for rotating the transfer roll 423 is not particularly limited, and for example, a belt and a pulley may be used. Good.

Furthermore, in the above embodiment, the transfer roll 23 is rotated by the forming

servomotors

431A and 431B and the

stages

428A and 428B are moved in the Y direction. However, the present invention is not limited to this, and means for rotating the transfer roll 423 is not limited thereto. Further, as means for moving the

stages

428A and 428B, different motors may be used, and the respective motors may be driven synchronously.

Here, when the light guide plate 407 and the transfer roll 423 are in contact with each other, if the rotational speed of the transfer roll 423 and the moving speed of the

stages

428A and 428B are greatly shifted, the appearance of the light guide plate 407 is deteriorated. To do. Therefore, when a motor dedicated to the roll that rotates the transfer roll 423 is not installed, the diameter management of the transfer roll 423 is important. On the other hand, when a motor dedicated to the roll that rotates the transfer roll 423 is installed, the rotation speed of the motor can be adjusted according to the diameter of the transfer roll 423, so that the appearance defect of the light guide plate 407 is caused. Can be prevented.

In the above embodiment, the

stages

428A and 428B are arranged so as to sandwich the transfer roll 423, but it goes without saying that the number of stages supporting the light guide plate 407 may be one as shown in FIG. At this time, the light incident end surface 407a of the light guide plate 407 may be pressed against the transfer surface 423a of the transfer roll 423 as described above, but the transfer surface 423a of the transfer roll 423 is pressed against the light incident end surface 407a of the light guide plate 407. May be. Further, the number of light guide plates 407 supported on the stage is not limited to one, and may be a plurality.

Further, in the above embodiment, the roll shaft 423b of the transfer roll 423 extends in the apparatus vertical direction (Z direction). However, in the optical sheet processing apparatus of the present invention, the roll shaft 423b of the transfer roll 423 is in the horizontal direction (X direction). Alternatively, the present invention can be applied to those extending in the Y direction.

Moreover, although the said embodiment forms the uneven | corrugated | grooved part 409 in the light-incidence end surface 407a of the light-guide plate 407 with which the backlight unit 403 of the liquid crystal display device 401 used for a liquid crystal television is comprised, the optical of this invention The sheet processing apparatus and method can be applied to, for example, an optical sheet forming process as a light guide plate for illumination or decoration.

FIG. 46 is a schematic sectional view showing a liquid crystal display device including a light guide plate which is an optical sheet obtained by one embodiment of the optical sheet processing apparatus according to the present invention. In the figure, a liquid crystal display device 501 according to this embodiment is used for a liquid crystal television, for example. The liquid crystal display device 501 includes a liquid crystal panel 502 and an edge type backlight unit 503 disposed on the back side of the liquid crystal panel 502. The thickness of the liquid crystal panel 502 is, for example, about 1.8 mm.

The backlight unit 503 has a box-shaped metal backlight housing 504. A plurality of electronic components 505 are provided on the back surface (back surface) of the backlight housing 504 via a substrate (not shown). A plurality of LEDs 506 for irradiating light are attached to the inner wall surfaces of the backlight housing 504 facing each other.

In the backlight housing 504, a light guide plate 507 having a rectangular cross section for guiding the light emitted from the LED 506 to the liquid crystal panel 502 is accommodated via a reflection sheet 508. As shown in FIG. 47, the light incident end surface 507a of the light guide plate 507 is provided with an uneven portion 509 having a substantially corrugated cross section. The thickness of the light guide plate 507 is 3 mm, for example.

The light guide plate 507 is formed of a thermoplastic resin. Specifically, the light guide plate 507 is made of an amorphous resin having high dimensional accuracy, impact strength, and transparency. Examples of the amorphous resin include polymethyl methacrylate resin (PMMA), polystyrene (PS), polycarbonate (PC), cycloolefin polymer (COP), and methyl methacrylate-styrene copolymer resin (MS).

The light emitted from the LED 506 is incident on the light incident end surface 507a of the light guide plate 507. The back surface of the light guide plate 507 is a reflective surface that reflects the light emitted from the LED 506, and the front surface of the light guide plate 507 is a light output surface that emits the light emitted from the LED 506 and the light reflected by the reflective surface. It has become. The back surface (reflecting surface) of the light guide plate 507 has a structure that easily reflects and scatters light, such as dot pattern printing with ink.

On the front side of the light guide plate 507, an optical film group 510 formed by laminating a plurality of (here, three) optical films is disposed. The thickness of the optical film group 510 is, for example, about 0.2 mm. The edges of the light guide plate 507 and the optical film group 510 are fixed to the backlight housing 504 by a frame body 511 made of resin (for example, PC). The liquid crystal panel 502 is fixed to the backlight unit 503 by a metal frame body 512.

FIG. 48 is a flowchart showing a process for manufacturing the light guide plate 507 described above. In the figure, first, a light guide plate original plate is produced by a melt extrusion sheet forming process or the like (step S501). Subsequently, the light guide plate original plate is roughly cut and cut using a panel saw, a running saw, or the like to obtain the light guide plate 507 (step S502). Subsequently, the mirror surface processing is performed on the light incident end surface 507a of the light guide plate 507 using a mirror processing machine (step S503). Then, the uneven | corrugated | grooved part 509 is formed in the light-incidence end surface 507a by performing a thermal transfer process to the light-incidence end surface 507a of the light-guide plate 507 (step S504). Note that step S503 is not necessarily performed.

FIG. 49 is a plan view showing an embodiment of an optical sheet processing apparatus according to the present invention. 50 is a front view of the optical sheet processing apparatus shown in FIG. 49, FIG. 51 is a sectional view taken along the line VI-VI in FIG. 50, and FIG. 52 is an enlarged view of the relevant part in FIG. 53 is an enlarged cross-sectional view taken along the line VIII-VIII in FIG. FIG. 54 is a perspective view schematically showing the optical sheet processing apparatus shown in FIG. 49 and the like. In each figure, the optical sheet processing apparatus 520 of this embodiment is used when step S504 shown in FIG. 48 is performed.

The optical sheet processing apparatus 520 includes an apparatus frame 521. A rack 522 is disposed at the center of the apparatus frame 521, and a metal transfer roll 523 is rotatably supported on the rack 522 (see FIG. 51). As shown in FIG. 54, a transfer concavo-convex portion 519 is formed on the outer peripheral surface 523 a of the transfer roll 523 along the circumferential direction of the transfer roll 523. The outer peripheral surface 523a of the transfer roll 523 serves as a transfer surface for providing an uneven portion to the light incident end surface 507a of the light guide plate 507. The transfer uneven portion 519 is formed in a prism shape or a lenticular shape with respect to the axial direction of the transfer roll 523, for example. The unevenness depth F (see FIG. 55) of the transfer uneven portion 519 is 0.01 mm to 0.30 mm.

As shown in FIG. 51, the transfer roll 523 is an electric heater roll in which an induction coil 541 (heater unit) is incorporated. A power supply unit 542 that supplies a high-frequency current to the induction coil 541 is disposed above the transfer roll 523. The induction coil 541 and the power supply unit 542 constitute a heating unit that heats the transfer roll 523. As the transfer roll 523, an oil heater roll heated by oil may be used.

50,

pedestals

525A and 525B are arranged below the apparatus frame 521 so as to sandwich the transfer roll 523 in the apparatus horizontal direction (X direction).

Stage bases

526A and 526B are attached to the upper portions of the

bases

525A and 525B through the

guide rails

527A and 527B so as to be movable in the longitudinal direction of the apparatus (Y direction).

Stages

528A and 528B are attached to the upper portions of the

stage bases

526A and 526B so as to be movable in the left-right direction (X direction) of the apparatus via

guide rails

529A and 529B.

A light guide plate 507 is placed (supported) on the upper surfaces of the

stages

528A and 528B. Light guide plates 507 of various sizes can be placed vertically or horizontally on the upper surfaces of the

stages

528A and 528B (see FIG. 49). The vertical placement is such that the longitudinal direction of the light guide plate 507 coincides with the Y direction. The horizontal placement is such that the longitudinal direction of the light guide plate 507 coincides with the X direction.

As shown in FIG. 54, the light guide plate 507 placed on the upper surfaces of the

stages

528A and 528B is pressed against the

stages

528A and 528B by the

clamp plates

518A and 518B. The light guide plate 507 is placed on the upper surfaces of the

stages

528A and 528B so as to protrude by a predetermined amount from the

clamp plates

518A and 518B to the side corresponding to the transfer roll 523.

At this time, as shown in FIG. 56, when bending stress is applied to the protruding portion of the light guide plate 507 from the

clamp plates

518A and 518B (only the clamp plate 518A is shown in FIG. 56), for example, the thickness of the light guide plate 507 is 1. In the case of .5 to 4.0 mm, even if the projection amount of the light guide plate 507 is 10 mm, the bending amount of the light guide plate 507 is 1.0 mm or less, and the thickness of the light guide plate 507 is as thin as 0.6 to 0.8 mm. In this case, if the protruding amount of the light guide plate 507 is 3 mm, the bending amount of the light guide plate 507 is 1.0 mm or less. It has been confirmed through experiments that the light guide plate 507 is not crushed if the bending amount of the light guide plate 507 is 1.0 mm or less.

Press cylinders

530A and 530B for moving the

stages

528A and 528B in the X direction are attached to the upper portions of the

stage bases

526A and 526B, respectively (see FIG. 50). The

pressure cylinders

530A and 530B are pressure applying means for applying pressure to the

stages

528A and 528B so as to press the light incident end surface 507a of the light guide plate 507 placed on the

stages

528A and 528B against the transfer surface 523a of the transfer roll 523. Is configured.

Further, as shown in FIGS. 50 to 53, the optical sheet processing apparatus 520 is disposed so as to sandwich the transfer roll 523 in an oblique direction with respect to the X direction and the Y direction, corresponding to the

stages

528A and 528B. Serving

motors

531A and 531B are provided. Pinion gears 532A and 532B are attached to the output shafts 531a of the forming

servomotors

531A and 531B, respectively. Rack gears 533A and 533B extending in the Y direction and meshing with the pinion gears 532A and 532B are provided on the inner side surfaces of the lower portions of the

stage bases

526A and 526B, respectively. Accordingly, when the forming

servo motors

531A and 531B are driven to rotate, the rotation of the forming

servo motors

531A and 531B is transmitted to the

stage bases

526A and 526B via the pinion gears 532A and 532B and the rack gears 533A and 533B, and the stage base 526A. , 526B move in the Y direction, and accordingly, the

stages

528A, 528B move in the Y direction.

In the lower part of the rack 522,

shafts

534A and 534B extending in the vertical direction (Z direction) of the apparatus are rotatably supported. These

shafts

534A and 534B are arranged so as to sandwich the transfer roll 523 in the Y direction. Spur gears 535A and 535B that mesh with the above-described pinion gears 532A and 532B are provided in the middle portions of the

shafts

534A and 534B, respectively.

Electromagnetic clutches

536A and 536B are attached to the upper ends of the

shafts

534A and 534B, respectively.

The support plate 522a is connected to the rack 522.

Shafts

537A and 537B extending downward are respectively rotatably supported at portions of the support plate 522a corresponding to the

shafts

534A and 534B. Spur gears 538A and 538B are provided in the middle of the

shafts

537A and 537B, respectively. The lower ends of the

shafts

537A and 537B are attached to the

electromagnetic clutches

536A and 536B, respectively.

The electromagnetic clutch 536A interrupts the transmission of power from the spur gear 535A to the spur gear 538A by intermittently connecting the

shafts

534A and 537A. Specifically, when the electromagnetic clutch 536A is ON, the

shafts

534A and 537A are connected to each other, and when the electromagnetic clutch 536A is OFF, the connections between the

shafts

534A and 537A are released. The electromagnetic clutch 536B interrupts the transmission of power from the spur gear 535B to the spur gear 538B by intermittently connecting the

shafts

534B and 537B. Specifically, when the electromagnetic clutch 536B is ON, the

shafts

534B and 537B are connected to each other, and when the electromagnetic clutch 536B is OFF, the connections between the

shafts

534B and 537B are released.

The roll shaft 523 b of the transfer roll 523 extends below the rack 522. A spur gear 539 that meshes with the spur gears 538A and 538B is attached to the lower end of the roll shaft 523b.

When the forming servo motor 531A is rotated with the electromagnetic clutch 536A turned on, the transfer is performed via the pinion gear 532A, the spur gear 535A, the shaft 534A, the electromagnetic clutch 536A, the shaft 537A, the spur gear 538A, and the spur gear 539. The roll 523 rotates. Further, when the forming servo motor 531B is driven to rotate while the electromagnetic clutch 536B is ON, the pinion gear 532B, the spur gear 535B, the shaft 534B, the electromagnetic clutch 536B, the shaft 537B, the spur gear 538B, and the spur gear 539 are passed through. As a result, the transfer roll 523 rotates. Accordingly, the stage 528A can be moved and the transfer roll 523 can be rotated by the forming servo motor 531A, and the stage 528B can be moved and the transfer roll 523 can be rotated by the forming servo motor 531B.

In the above, the forming

servo motors

531A and 531B, the pinion gears 532A and 532B, the

shafts

534A and 534B, the spur gears 535A and 535B, the

electromagnetic clutches

536A and 536B, the

shafts

537A and 537B, the spur gears 538A and 538B, and the spur gear 539 are Rotating means for rotating the transfer roll 523 is configured.

Servo motors

531A and 531B for molding, pinion gears 532A and 532B, rack gears 533A and 533B,

stage bases

526A and 526B, and

guide rails

527A and 527B are arranged so that the

stage

528A and 528B are in the direction of forming the uneven portion 509 with respect to the transfer roll 523. The moving means to move relatively is comprised.

Further, as shown in FIGS. 49 and 57, on the side corresponding to the transfer roll 523 with respect to the

stages

528A and 528B, the X direction of the light guide plate 507 with respect to the transfer roll 523 (the direction perpendicular to the formation direction of the uneven portion 509) The cylindrical positioning rollers 551 for setting the reference position) are respectively arranged. That is, two positioning rollers 551 are disposed between the

stages

528A and 528B. The positioning roller 551 is freely rotatable around an axis parallel to the Z direction (the roll axis direction of the transfer roll 523).

On the opposite side of the positioning rollers 551 in the

stages

528A and 528B, pressing bars 552 for pressing the light guide plate 507 placed on the

stages

528A and 528B against the positioning rollers 551 are arranged. The pressing bar 552 extends in the Y direction (the moving direction of the

stages

528A and 528B). The pressing bar 552 slides the upper surfaces of the

stages

528A and 528B in the X direction by the positioning actuator 553. Although not shown in detail, the positioning actuator 553 is configured by an air cylinder, a solenoid, or the like.

When the uneven portion 509 is formed on the light incident end surface 507a of the light guide plate 507 using the optical sheet processing apparatus 520 configured as described above, first, as shown in FIG. 58, the

stages

528A and 528B (in FIG. 58). The light guide plate 507 is placed on the upper surface (not shown), and the light incident end surface 507 a of the light guide plate 507 is applied to the positioning roller 551. Then, the pressing bar 552 is moved in the X direction by a positioning actuator 553 (not shown in FIG. 58), and the light guide plate 507 is pressed against the positioning roller 551 by the pressing bar 552. As a result, the light guide plate 507 is positioned in the X direction with respect to the transfer roll 523. Accordingly, the distance between the light incident end surface 507a of the light guide plate 507 and the transfer surface 523a of the transfer roll 523 is a constant amount.

Subsequently, the light guide plate 507 is moved in the Y direction toward the transfer roll 523 by moving the

stages

528A and 528B in the Y direction toward the transfer roll 523 by the moving means. Immediately before the light guide plate 507 reaches the transfer roll 523, the

stage

528A, 528B is moved by a predetermined amount in the X direction by pressing

cylinders

530A, 530B (not shown in FIG. 58), so that the light incident end surface of the light guide plate 507 is obtained. 507a is pressed against the transfer surface 523a of the transfer roll 523 (see the two-dot chain line in FIG. 58).

Thereafter, the light guide plate 507 is moved in the Y direction toward the transfer roll 523 by the moving means while the transfer roll 523 is rotated by the rotating means. As a result, the uneven portion for transfer 519 of the transfer roll 523 is transferred to the light incident end surface 507a of the light guide plate 507, and the uneven portion 509 is provided to the light incident end surface 507a.

An example of a molding process for forming the uneven portion 509 on the light incident end surface 507a of the light guide plate 507 will be specifically described with reference to FIG. Here, description of the step of setting the reference position of the light guide plate 507 with respect to the transfer roll 523 by pressing the light guide plate 507 against the positioning roller 551 by the pressing bar 552 is omitted. In this molding process, two workers W are arranged on the front side of the optical sheet processing apparatus 520 (see FIG. 49). At this time, the transfer roll 523 is heated to a certain temperature (for example, 100 ° C. to 200 ° C.) by the induction coil 541 and the power supply unit 542.

First, in the state where both the stage 528A on which the molded light guide plate 507 is placed and the stage 528B on which the light guide plate 507 before molding is placed are positioned on the front side of the optical sheet processing apparatus 520, the servo motor 531B for molding. Is rotated in a predetermined direction to turn on the electromagnetic clutch 536B. Note that the drive of the molding servo motor 531A is stopped, and the electromagnetic clutch 536A is OFF.

Then, as shown in FIG. 59A, the stage 528B moves to the rear side while the transfer roll 523 rotates counterclockwise. At this time, a constant pressure (for example, 0.05 MPa to 50 MPa) is applied to the stage 528B so that the light incident end surface 507a of the light guide plate 507 placed on the stage 528B is pressed against the transfer surface 523a of the transfer roll 523 by the pressing cylinder 530B. Is applied. As a result, the transfer uneven portion 519 of the transfer roll 523 is transferred to the light incident end surface 507a of the light guide plate 507 placed on the stage 528B. While the light guide plate 507 placed on the stage 528B is being molded as described above, the molded light guide plate 507 is taken out from the stage 528A.

Next, the drive of the molding servo motor 531B is stopped, and the electromagnetic clutch 536B is turned OFF. Then, as shown in FIG. 59B, the rotation of the transfer roll 523 stops, and the stage 528B on which the molded light guide plate 507 is placed stops on the rear side of the optical sheet processing apparatus 520. In the meantime, a new light guide plate 507 is placed on and placed on the stage 528A.

Next, the stage 528A on which the new light guide plate 507 is placed is located on the front side of the optical sheet processing apparatus 520, and the stage 528B on which the molded light guide plate 507 is placed is located on the rear side of the optical sheet processing apparatus 520. In the state where the electromagnetic clutch 536B is turned off, the forming servo motor 531B is rotated in the opposite direction. Then, as shown in FIG. 59C, the stage 528B on which the molded light guide plate 507 is placed moves to the front side while the rotation of the transfer roll 523 is stopped. At this time, no pressure is applied to the stage 528B by the pressing cylinder 530B. Then, when the stage 528B returns to the original position, the driving of the forming servo motor 531B is stopped. Meanwhile, the stage 528A on which the new light guide plate 507 is placed stands by at the same position.

Next, with the stage 528A on which the new light guide plate 507 is placed and the stage 528B on which the molded light guide plate 507 is placed positioned on the front side of the optical sheet processing apparatus 520, the molding servo motor 531A is moved. The electromagnetic clutch 536A is turned on by rotating in a predetermined direction.

Then, as shown in FIG. 59 (d), the stage 528A moves to the rear side while the transfer roll 523 rotates in the clockwise direction. At this time, a constant pressure is applied to the stage 528A by the pressing cylinder 530A so that the light incident end surface 507a of the light guide plate 507 placed on the stage 528A is pressed against the transfer surface 523a of the transfer roll 523. As a result, the transfer uneven portion 519 of the transfer roll 523 is transferred to the light incident end surface 507a of the light guide plate 507 placed on the stage 528A. While the light guide plate 507 placed on the stage 528A is being molded in this way, the molded light guide plate 507 is taken out from the stage 528B.

Next, the drive of the molding servo motor 531A is stopped, and the electromagnetic clutch 536A is turned OFF. Then, as shown in FIG. 59 (e), the rotation of the transfer roll 523 stops, and the stage 528A on which the molded light guide plate 507 is placed stops on the rear side of the optical sheet processing apparatus 520. In the meantime, a new light guide plate 507 is placed and placed on the stage 528B.

Next, the stage 528A on which the molded light guide plate 507 is placed is located on the rear side of the optical sheet processing apparatus 520, and the stage 528B on which a new light guide plate 507 is placed is located on the front side of the optical sheet processing apparatus 520. In this state, the molding servo motor 531A is rotated in the opposite direction while the electromagnetic clutch 536A is turned off.

Then, as shown in FIG. 59 (f), the stage 528A on which the molded light guide plate 507 is placed moves to the front side while the rotation of the transfer roll 523 is stopped. At this time, no pressure is applied to the stage 528A by the pressing cylinder 530A. When the stage 528A returns to the original position, the driving of the forming servo motor 531A is stopped. Meanwhile, the stage 528B on which the new light guide plate 507 is placed stands by at the same position.

Thus, in the main forming step, while the molded light guide plate 507 placed on the stage 528A is taken out and a new light guide plate 507 is put on the stage 528A, the light guide plate 507 is placed on the stage 528B. An uneven portion 509 is formed on the light incident end face 507a of the placed light guide plate 507, the molded light guide plate 507 placed on the stage 528B is taken out, and a new light guide plate 507 is placed on the stage 528B. During the process, the uneven portion 509 is formed on the light incident end surface 507a of the light guide plate 507 placed on the stage 528A.

At this time, the moving speed of the

stages

528A and 528B is not necessarily constant. For example, when a plurality of LEDs 506 are arranged facing the light incident end surface 507a of the light guide plate 507, the uneven portion 509 may be formed only on the light incident end surface 507a around the LED 506. Therefore, when pressing the transfer surface 523a of the transfer roll 523 and the light incident end surfaces 507a of the light guide plate 507, when the light incident end surface 507a at the position facing the LED 506 and the transfer surface 523a are in contact with each other, a desired uneven portion 509 is formed. When the

stages

528A and 528B are moved at the transfer (molding) speed obtained and the other light incident end surface 507a and the transfer surface 523a are in contact with each other, the

stages

528A and 528B may be moved at a higher speed. Thereby, the processing tact of the light guide plate 507 can be improved. The light incident end face 507a around the LED 506 indicates +1 mm from the width size of the LED 506 in the direction orthogonal to the thickness direction of the light guide plate 507.

As described above, in the present embodiment, the transfer roll 523 is heated and the transfer surface 523a of the transfer roll 523 and the light incident end surface 507a of the light guide plate 507 are pressed against each other to be provided on the transfer surface 523a of the transfer roll 523. The uneven portion for transfer 519 is thermally transferred to the light incident end surface 507a of the light guide plate 507 so that the uneven portion 509 is formed on the light incident end surface 507a of the light guide plate 507. Chips are not generated unlike the case where the uneven portion 509 is formed on the light incident end surface 507a of the light guide plate 507. Accordingly, the chips are not attached to or mixed in the light guide plate 507, and the product quality can be stabilized.

Incidentally, when the rough cutting process (step S502) and the mirror finishing process (step S503) in the manufacturing process of the light guide plate 507 shown in FIG. 48 are performed in a state where a plurality of sheets are laminated, each light guide plate 507 is Finished with some tolerance. For example, when 54 sheets of 550 mm × 320 mm × 3 mm are processed at once, it has been experimentally known that the outer dimension of the light guide plate 507 is shifted by 0.12 mm at the maximum. As described above, since the unevenness depth F (see FIG. 55) of the transfer uneven portion 519 is 0.01 mm to 0.30 mm, a deviation of 0.12 mm in the outer dimension of the light guide plate 507 is allowed. I can't. Specifically, when the deviation of the outer dimension of the light guide plate 507 is 0.12 mm, the contact distance D (see FIG. 58) between the light incident end surface 507a of the light guide plate 507 and the transfer surface 523a of the transfer roll 523 changes greatly. For this reason, the transfer rate of the transfer uneven portion 519 of the transfer roll 523 is also greatly changed, and stable transfer accuracy cannot be obtained.

On the other hand, in this embodiment, a positioning roller 551 for setting a reference position in the X direction of the light guide plate 507 with respect to the transfer roll 523 is disposed on the side corresponding to the transfer roll 523 with respect to the

stages

528A and 528B. Since the light guide plate 507 is pressed against the positioning roller 551 by the pressing bar 552, the distance between the light incident end surface 507a of the light guide plate 507 and the transfer surface 523a of the transfer roll 523 is always a constant amount. Therefore, when the

stages

528A and 528B are moved by a predetermined amount in the X direction by the

pressing cylinders

530A and 530B, the contact distance D between the light incident end surface 507a of the light guide plate 507 and the transfer surface 523a of the transfer roll 523 is always constant. It becomes quantity. As a result, even if the outer dimensions of the light guide plate 507 differ from one sheet to another due to tolerances when processing the outer shape of the light guide plate 507, the transfer rate of the transfer irregularities 519 of the transfer roll 523 is substantially constant, so that stable transfer Accuracy can be obtained. As a result, the quality of the product can be further stabilized.

In addition, since the positioning roller 551 is a cylindrical roller that can freely rotate around an axis parallel to the Z direction, when the light guide plate 507 moves toward the transfer roll 523 in contact with the positioning roller 551, Then, the positioning roller 551 rotates. Therefore, the light guide plate 507 is prevented from being damaged.

In this embodiment, the pressing bar 552 is configured to slide the upper surfaces of the

stages

528A and 528B and press the light guide plate 507 against the positioning roller 551. However, the configuration is not particularly limited, and the pressing bar 552, for example. A gap may be formed between the stage 528A and the upper surfaces of the

stages

528A and 528B, wall portions may be provided on both sides of the

stages

528A and 528B, and the pressing bar 552 may slide along the inner side surface of each wall portion. . Further, instead of the pressing bar 552, a plurality of pressing pins arranged in the X direction may be provided, and these pressing pins may slide the upper surfaces of the

stages

528A and 528B and press the light guide plate 507.

FIG. 60 is a perspective view showing a modification of the structure for setting the reference position of the light guide plate 507 with respect to the transfer roll 523. In the drawing, a pressing member 555 for pressing the light guide plate 507 against the positioning roller 551 is disposed on the opposite side of the positioning roller 551 in the

stages

528A and 528B. The pressing member 555 has a bar 556 extending in the Y direction, and a plurality of (here, two) pressing pins 557 projecting toward the

stages

528A and 528B are attached to the lower surface of the bar 556. A plurality of (here, two) guide grooves 558 are formed on the upper surfaces of the

stages

528A and 528B so as to extend in the X direction and slide the pressing pins 557.

In such a configuration, when the light guide plate 507 is pressed against the positioning roller 551 by the pressing member 555, the pressing pin 557 slides on the bottom surface of the guide groove 558, so that the upper surfaces of the

stages

528A and 528B and the lower surface of the bar 556 are formed. There is no rubbing and scratching. In addition, since the light guide plate 507 is pressed against the positioning roller 551 by the plurality of pressing pins 557 protruding from the lower surface of the bar 556, even if the gap between the upper surfaces of the

stages

528A and 528B and the lower surface of the bar 556 is large, for example, the thickness is 0. The thin light guide plate 507 having a thickness of 1 to 1.0 mm can be reliably pressed against the positioning roller 551.

Note that the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the positioning member for setting the reference position of the light guide plate 507 with respect to the transfer roll 523 is the columnar positioning roller 551 that can freely rotate. Etc.

In the above embodiment, the transfer roll 523 is rotated by meshing the spur gears. However, the mechanism for rotating the transfer roll 523 is not particularly limited, and for example, a belt and a pulley may be used. Good.

In the above-described embodiment, the transfer roll 523 is rotated by the forming

servomotors

531A and 531B and the

stages

528A and 528B are moved in the Y direction. However, the present invention is not limited to this, and means for rotating the transfer roll 523 is not limited thereto. Further, as means for moving the

stages

528A and 528B, different motors may be used, and the respective motors may be driven synchronously.

Here, when the light guide plate 507 and the transfer roll 523 come into contact with each other, if the rotational speed of the transfer roll 523 and the moving speed of the

stages

528A and 528B are greatly shifted, the appearance of the light guide plate 507 is deteriorated. To do. For this reason, in the case where a dedicated motor for rotating the transfer roll 523 is not installed, the diameter management of the transfer roll 523 is important. On the other hand, when a dedicated motor for rotating the transfer roll 523 is installed, the rotation speed of the motor can be adjusted in accordance with the diameter of the transfer roll 523, so that the appearance defect of the light guide plate 507 occurs. Can be prevented.

In the above embodiment, the

stages

528A and 528B are disposed so as to sandwich the transfer roll 523, but it goes without saying that the number of stages supporting the light guide plate 507 may be one as shown in FIGS. Yes. At this time, the light incident end surface 507a of the light guide plate 507 may be pressed against the transfer surface 523a of the transfer roll 523 as described above, but the transfer surface 523a of the transfer roll 523 is pressed against the light incident end surface 507a of the light guide plate 507. May be. Further, the number of light guide plates 507 supported on the stage is not limited to one, but may be a plurality.

Furthermore, although the said embodiment forms the uneven | corrugated | grooved part 509 in the light-incidence end surface 507a of the light-guide plate 507 comprised in the backlight unit 503 of the liquid crystal display device 501 used for a liquid crystal television, the optical of this invention The sheet processing apparatus and method can be applied to, for example, an optical sheet forming process as a light guide plate for illumination or decoration.

DESCRIPTION OF SYMBOLS 107 ... Light guide plate (optical sheet), 107a ... Light-incidence end surface, 109 ... Uneven part, 120 ... Optical sheet processing apparatus, 121 ... Stage, 122 ... Clamp plate (clamp means), 124 ... Transfer die, 125 ... Rigid body roll , 125a ... peripheral surface (transfer surface), 126 ... concavo-convex part for transfer, 127 ... heating part (heating means), 128 ... pressure application part (pressure application means), 129 ... movement drive part (drive means), 130 ... Rotation drive unit (drive unit), 131... Movement drive unit (drive unit), 132... Stage, P... Pitch, H.
207 ... Light guide plate (optical sheet), 207 a ... Light incident end face, 209 ... Uneven part, 224 ... Transfer mold, 225 ... Rigid roll part, 225a ... Peripheral surface (transfer surface), 226 ... Uneven part for transfer.
307: Light guide plate (optical sheet), 307a: Light incident end surface, 309: Uneven portion, 319 ... Uneven portion for transfer, 320 ... Optical sheet processing device, 323 ... Transfer roll, 323a ... Outer peripheral surface (transfer surface), 323b ... Roll shaft, 326A, 326B ... stage base (moving power transmission mechanism, moving means), 327A, 327B ... guide rail (moving power transmission mechanism, moving means), 328A, 328B ... stage, 330A, 330B ... pressing cylinder ( Pressure application means), 331A, 331B ... molding servo motor (rotation means, movement means), 332A, 332B ... pinion gear (rotation power transmission mechanism, rotation means, movement power transmission mechanism, movement means), 333A, 333B ... Rack gear (moving power transmission mechanism, moving means), 334A, 334B ... Shaft (rotary power transmission) , Rotation means), 335A, 335B ... spur gear (rotation power transmission mechanism, rotation means), 336A, 336B ... electromagnetic clutch (rotation power transmission mechanism, rotation means), 337A, 337B ... shaft (rotation power transmission mechanism) , Rotating means), 338A, 338B ... spur gear (second spur gear, rotating power transmission mechanism, rotating means), 339 ... spur gear (first spur gear, rotating power transmission mechanism, rotating means), 341 ... induction Coil (heating means), 342... Power supply (heating means).
407 ... Light guide plate (optical sheet), 407a ... light incident end surface, 409 ... uneven portion, 420 ... optical sheet processing apparatus, 422 ... rack (second moving means), 423 ... transfer roll, 423a ... outer peripheral surface (transfer surface) 423b ... roll shaft, 426A, 426B ... stage base (first moving means), 427A, 427B ... guide rail (first moving means), 428A, 428B ... stage, 430A, 430B ... pressure cylinder (pressure applying means), 431A, 431B ... Molding servo motor (rotating means, first moving means), 432A, 432B ... Pinion gear (rotating means, first moving means), 433A, 433B ... Rack gear (first moving means), 434A, 434B ... Shaft (rotating means), 435A, 435B ... spur gear (rotating means), 436A, 436B ... electromagnetic clutch ( 437A, 437B ... shaft (rotating means), 438A, 438B ... spur gear (rotating means), 439 ... spur gear (rotating means), 441 ... induction coil (heating means), 442 ... power supply (heating means) , 443 ... Ball screw (second moving means), 444 ... Main elevating body (second moving means), 445 ... Elevating servo motor (second moving means), 446 ... Linear guide (second moving means), 447 ... Auxiliary lifting body (second moving means).
507 ... Light guide plate (optical sheet), 507 a ... Light incident end face, 509 ... Uneven portion, 519 ... Uneven portion for transfer, 520 ... Optical sheet processing device, 523 ... Transfer roll, 523a ... Outer peripheral surface (transfer surface), 523b ... Roll shaft, 526A, 526B ... Stage base (moving means), 527A, 527B ... Guide rail (moving means), 528A, 528B ... Stage, 530A, 530B ... Press cylinder (pressure applying means), 531A, 531B ... Servo for molding Motor (rotating means, moving means), 532A, 532B ... Pinion gear (rotating means, moving means), 533A, 533B ... Rack gear (moving means), 534A, 534B ... Shaft (rotating means), 535A, 535B ... Spur gear ( Rotating means), 536A, 536B ... Electromagnetic clutch (rotating means), 537A, 537B Shaft (rotating means), 538A, 538B ... spur gear (rotating means), 539 ... spur gear (rotating means), 541 ... induction coil (heating means), 542 ... power supply (heating means), 551 ... positioning roller ( Positioning member), 552... Pressing bar (pressing member), 555... Pressing member, 556... Bar, 557.

Claims

An optical sheet manufacturing method for manufacturing an optical sheet made of a thermoplastic resin and having an uneven portion on the light incident end face,
A preparation step of preparing a transfer mold having a transfer surface for imparting the concavo-convex portion to the light incident end surface of the optical sheet;
An optical sheet manufacturing method comprising: forming the concave and convex portions on the light incident end surface by pressing the transfer surface and the light incident end surface with the transfer mold heated.
2. The optical sheet according to claim 1, wherein in the processing step, the transfer mold is heated to a temperature that is equal to or higher than a Vicat softening temperature of the thermoplastic resin and is equal to or lower than a Vicat softening temperature of the thermoplastic resin + 50 ° C. 3. Production method.
The transfer mold has a metal roll part,
The peripheral surface of the roll part is the transfer surface,
In the processing step, the roll unit is rotated in a state where the transfer surface and the light incident end surface are pressed against each other, and the roll unit is relative to the optical sheet along the light incident end surface of the optical sheet. The optical sheet manufacturing method according to claim 1, wherein the uneven portion is formed on the light incident end face.
The transfer surface is provided with a prism-shaped or lenticular-shaped concavo-convex portion for transfer,
The pitch of the uneven portions for transfer is 10 μm to 500 μm,
The method for producing an optical sheet according to any one of claims 1 to 3, wherein the height of the concavo-convex portion for transfer is 10 袖 m to 300 袖 m.
5. The optical sheet manufacturing method according to claim 1, wherein, in the processing step, the transfer surface and the light incident end surface are pressed against each other with a pressure of 0.05 MPa to 50 MPa.
6. The method for producing an optical sheet according to claim 1, wherein an amorphous resin is used as the thermoplastic resin.
2. The optical sheet manufacturing method according to claim 1, wherein, in the processing step, the transfer mold and the optical sheet are released before the transfer surface is completely filled with the thermoplastic resin.
8. The optical sheet according to claim 7, wherein, in the processing step, the transfer mold is heated to a temperature that is equal to or higher than a Vicat softening temperature of the thermoplastic resin and is equal to or lower than a Vicat softening temperature of the thermoplastic resin + 40 ° C. Production method.
The transfer surface is provided with an uneven portion for transfer having a prism shape or a lenticular shape,
In the processing step, when the ratio F / Wa between the length F of the base flat region and the length Wa of the convex region at one pitch of the uneven portion for transfer is 0% to 50%, The concavo-convex portion is formed on the light incident end face so that a ratio F ′ / Wa ′ of the length F ′ of the flat tip end region to the length Wa ′ of the concave region at 1 pitch is 10% to 300%. The method for producing an optical sheet according to claim 7 or 8, wherein:
An optical sheet processing apparatus for forming an uneven portion on a light incident end face of an optical sheet made of a thermoplastic resin,
A stage for supporting the optical sheet;
A transfer mold having a transfer surface for imparting the concavo-convex portion to the light incident end surface of the optical sheet supported by the stage;
Heating means for heating the transfer mold;
Pressure applying means for applying pressure so as to press the transfer surface and the light incident end surfaces;
An optical sheet processing apparatus comprising: a drive unit that drives at least one of the stage and the transfer mold so as to form the uneven portion on the light incident end surface.
The transfer mold has a metal roll part,
The peripheral surface of the roll part is the transfer surface,
The said drive means has a means to rotate the said roll part, and a means to move the said roll part relatively with respect to the said stage along the light-incidence end surface of the said optical sheet, It is characterized by the above-mentioned. The optical sheet processing apparatus as described.
12. The optical sheet processing apparatus according to claim 10, further comprising a clamping unit that clamps the optical sheet with respect to the stage.
An optical sheet processing apparatus for forming an uneven portion on a light incident end face of an optical sheet made of a thermoplastic resin,
A metal transfer roll having a transfer surface for imparting the concavo-convex portion to the light incident end surface of the optical sheet;
A pair of stages arranged to sandwich the transfer roll and supporting the optical sheet;
Heating means for heating the transfer roll;
Pressure applying means for applying pressure to the stage so as to press the transfer surface and the light incident end surfaces;
A rotating means for rotating the transfer roll;
An optical sheet processing apparatus comprising: a moving unit configured to move the stage in the forming direction of the uneven portion with respect to the transfer roll.
The rotating means includes a pair of motors provided corresponding to the stages, and a rotational power transmission mechanism that transmits a driving force of the motors to the transfer roll.
The optical sheet processing apparatus according to claim 13, wherein the moving unit includes the pair of motors and a moving power transmission mechanism that transmits a driving force of the motors to the stages.
The rotation power transmission mechanism includes a first spur gear attached to a roll shaft of the transfer roll, a pair of second spur gears that mesh with the first spur gear, and the second spur gear to the second spur gear. A pair of clutches for intermittently transmitting and receiving the driving force of each motor,
The power transmission mechanism for movement includes a pair of racks provided on each stage, and a pair of pinions attached to output shafts of the motors and meshing with the racks, respectively. The optical sheet processing apparatus according to claim 14.
An optical sheet processing method for forming a concavo-convex portion on a light incident end face of an optical sheet made of a thermoplastic resin,
A preparation step of preparing the optical sheet processing apparatus according to any one of claims 13 to 15,
While heating the transfer roll and applying pressure to the stage so as to press the transfer surface and the light incident end surfaces, the stage is moved with respect to the transfer roll while rotating the transfer roll. Forming the concavo-convex part on the light incident end surface by moving in the forming direction of the part,
In the molding step, the optical sheet supported on the other of the pair of stages is not formed on the light incident end face of the optical sheet supported on one of the pair of stages. An optical sheet processing method, wherein the uneven portion is formed on a light incident end surface.
The molding step includes
While taking out the optical sheet with respect to the one stage, the other stage is moved from one side to the other side, and the unevenness is formed on the light incident end surface of the optical sheet supported by the other stage. A first step of forming a portion;
After performing the first step, while the optical sheet is being taken out from the other stage, the one stage is moved from the one side to the other side and supported by the one stage. A second step of forming the concavo-convex portion on the light incident end face of the optical sheet;
After performing the second step, while taking out the optical sheet from the one stage, the other stage is moved from the other side to the one side and is supported by the other stage. A third step of forming the uneven portion on the light incident end surface of the optical sheet;
After performing the third step, while the optical sheet is being taken out from the other stage, the one stage is moved from the other side to the one side and supported by the one stage. The optical sheet processing method according to claim 16, further comprising: a fourth step of forming the uneven portion on the light incident end face of the optical sheet.
The molding step includes
While taking out the optical sheet with respect to the one stage, the other stage is moved from one side to the other side, and the unevenness is formed on the light incident end surface of the optical sheet supported by the other stage. A first step of forming a portion;
A second step of moving the other stage from the other side to the one side while the one stage is waiting after performing the first step;
After performing the second step, while taking out the optical sheet from the other stage, the one stage is moved from the other side to the one side and supported by the one stage. A third step of forming the uneven portion on the light incident end surface of the optical sheet;
17. The fourth step of moving the one stage from the one side to the other side while the other stage is waiting after the third step is performed. The optical sheet processing method as described.
The molding step includes
While taking out the optical sheet with respect to the one stage, the other stage is moved from one side to the other side, and the unevenness is formed on the light incident end surface of the optical sheet supported by the other stage. A first step of forming a portion;
A second step of moving the other stage from the other side to the one side while the one stage is waiting after performing the first step;
After performing the second step, while the optical sheet is being taken out from the other stage, the one stage is moved from the one side to the other side and supported by the one stage. A third step of forming the uneven portion on the light incident end surface of the optical sheet;
17. The fourth step of moving the one stage from the other side to the one side while the other stage is waiting after the third step is performed. The optical sheet processing method as described.
An optical sheet processing apparatus for forming an uneven portion on a light incident end face of an optical sheet made of a thermoplastic resin,
A stage for supporting the optical sheet;
A metal transfer roll having a transfer surface for imparting the concavo-convex portion to the light incident end surface of the optical sheet supported by the stage;
Heating means for heating the transfer roll;
Pressure applying means for applying pressure so as to press the transfer surface and the light incident end surfaces;
A rotating means for rotating the transfer roll;
First moving means for moving the stage relative to the transfer roll in the formation direction of the concavo-convex portion;
An optical sheet processing apparatus comprising: a second moving unit that moves the transfer roll relative to the stage in a roll axis direction of the transfer roll.
The optical sheet processing apparatus according to claim 20, wherein a masking film is bonded to a main surface of the optical sheet.
The optical sheet processing apparatus according to claim 20 or 21, wherein the heating means includes an induction coil provided in the transfer roll and a power supply unit that supplies a current to the induction coil.
An optical sheet processing method for forming a concavo-convex portion on a light incident end face of an optical sheet made of a thermoplastic resin,
A preparation step of preparing the optical sheet processing apparatus according to any one of claims 20 to 22;
While the transfer roll is heated and the pressure is applied so as to press the transfer surface and the light incident end faces, the stage is formed with respect to the transfer roll while rotating the transfer roll. A forming step of forming the concavo-convex portion on the light incident end face by moving in a direction relatively;
After carrying out the forming step, when the foreign matter adheres to the transfer surface, the transfer roll is arranged so as to avoid the light incident end face coming into contact with the foreign matter attachment location on the transfer surface. An avoiding step of moving the transfer roll relative to the stage in the roll axis direction of the transfer roll.
An optical sheet processing apparatus for forming an uneven portion on a light incident end face of an optical sheet made of a thermoplastic resin,
A stage for supporting the optical sheet;
A metal transfer roll having a transfer surface for imparting the concavo-convex portion to the light incident end surface of the optical sheet supported by the stage;
A positioning member disposed on a side corresponding to the transfer roll with respect to the stage, and a positioning member for setting a reference position of the optical sheet with respect to the transfer roll;
A pressing member for pressing the optical sheet against the positioning member;
Heating means for heating the transfer roll;
Pressure applying means for applying pressure so as to press the transfer surface and the light incident end surfaces;
A rotating means for rotating the transfer roll;
An optical sheet processing apparatus comprising: a moving unit configured to move the stage relative to the transfer roll in the formation direction of the uneven portion.
25. The optical sheet processing apparatus according to claim 24, wherein the positioning member is a freely rotatable roller.
26. The optical sheet processing apparatus according to claim 24, wherein the pressing member is at least one of a bar extending in the moving direction of the stage and a plurality of pins arranged side by side in the moving direction of the stage.
In the bar, the plurality of pins protrude to the stage side,
27. The optical sheet processing apparatus according to claim 26, wherein a plurality of guide grooves extending in the pressing direction of the optical sheet and sliding the pins are provided on the upper surface of the stage.
The optical sheet processing apparatus according to any one of claims 24 to 27, wherein a depth of the unevenness of the transfer surface is 0.01 mm to 0.30 mm.
An optical sheet processing method for forming a concavo-convex portion on a light incident end face of an optical sheet made of a thermoplastic resin,
A preparation step of preparing the optical sheet processing apparatus according to any one of claims 24 to 28;
A positioning step of setting a reference position of the optical sheet with respect to the transfer roll by pressing the optical sheet against the positioning member by the pressing member with the optical sheet supported on the stage;
While the transfer roll is heated and the pressure is applied so as to press the transfer surface and the light incident end faces, the stage is formed with respect to the transfer roll while rotating the transfer roll. And a forming step of forming the concavo-convex portion on the light incident end face by moving in a direction relatively.