JP2005046943A - Method and device for cutting plate material end face - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an end face cutting device capable of performing fine machining of repeated shape to the end face of a plate material easily in a short time and moreover uniformly with high accuracy. <P>SOLUTION: An ultrasonic cutting tool 112 provided with a cutting tool 110 having a cutting edge width not less than the thickness dimension of a cut resin molded plate 24 is held by a tool rest 106 so that the cutting tool faces the cut end face of the resin molded plate held and fixed by a clamper 36 and clamping bases 52, 80. While vibrating the cutting tool in a direction orthogonal to the end face of the resin molded plate, by an ultrasonic vibrator of the ultrasonic cutting tool, the tool rest is moved by a feed mechanism to repeatedly form fine unevenness of corrugated shape from the top view on the end face of the resin molded plate in the longitudinal direction of the end face. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for cutting an end surface of a flat plate material such as plastics, and in particular, when a flat plate end surface is cut, fine unevenness can be repeatedly formed in the longitudinal direction of the end surface. The present invention relates to a cutting method and apparatus.
[0002]
[Prior art]
As one of the backlight units of the liquid crystal display device, an edge light type surface light source device as shown in an exploded perspective view in FIG. 8 is used. In this edge light type surface light source device, a rod-like light source 2 such as a cold cathode tube is disposed on the side of a light guide plate 1 formed of polymethyl methacrylate (PMMA) or the like so as to face one end face thereof. The reflection sheet 3 is arranged on one side (lower surface side) of the optical plate 1 and the prism sheet 4 and the diffusion sheet 5 are laminated on the other side (upper surface side), respectively. The side is surrounded by a reflector 6 having a substantially semicircular cross section. The light guide plate 1 is manufactured by manufacturing a flat wedge-shaped plastic flat plate by injection molding of a resin such as PMMA, and cutting the end surface on the larger area side of the flat plate to form a light incident end surface. It is manufactured by. In the edge light type surface light source device having such a configuration, the illumination light emitted from the rod-like light source 2 is incident on the inside of the light guide plate 1 from the end surface of the light guide plate 1 together with the reflected light from the reflector 6, and the side surface in FIG. As shown in the figure, it is diffused while being reflected and refracted inside the light guide plate 1 and at the respective boundary surfaces of the sheets 3, 4, and 5. The diffused illumination light is emitted from the surface of the diffusion sheet 5 and irradiates the liquid crystal display device from the back side. In FIG. 9, reference numerals 7 and 8 denote reflection dots and prism forming portions formed on the light guide plate 1, respectively.
[0003]
As a problem in such an edge light type surface light source device, on the light exit surface of the light guide plate 1, a region z of about 5 mm to 6 mm from the end surface on the light source side becomes darker than other regions, and uneven brightness called “dark band”. Occurs. As a cause of the occurrence, when the illumination light emitted from the rod-shaped light source 2 passes through the light incident end surface of the light guide plate 1, the light refraction angle near the light incident end surface is small and light diffusion does not easily occur. ing. In order to solve such problems, it has been proposed to promote light diffusion on the light incident end surface of the light guide plate 1 by matting the end surface of the flat plate material that becomes the light guide plate. This mat processing is performed by a method such as blasting using a ceramic powder or the like.
[0004]
Further, it has also been proposed to promote light diffusion at the light incident end face of the light guide plate 1 by repeatedly forming protrusions having a triangular cross section on the end face of the flat plate member in the longitudinal direction of the end face (for example, (See Patent Document 1).
[0005]
One method of forming continuous protrusions on the end surface of a flat plate material is a cutting method, for example, attaching a carbide end mill to a milling machine and cutting the end surface of the flat plate material with extremely low speed feed. The way is done. Further, as a method other than the cutting method, a resin molding method using a mold is adopted.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-231320 (Page 4, FIGS. 1 and 2)
[0007]
[Problems to be solved by the invention]
By the way, in mat processing such as blasting using ceramic powder or the like, the luminance of the entire light exit surface of the light guide plate is lowered depending on the degree of the rough surface. For this reason, according to a certain research report, a range of 0.05 μm to 0.3 μm is recommended as the arithmetic average roughness Ra defined in JIS B0031-1994. However, this rule is merely an arithmetic average of the height differences of the peaks and valleys in the reference section of the roughness curve, and does not mean that the peaks and valleys in the reference section are evenly distributed with a certain height difference. Absent. Therefore, depending on this type of end face processing method, it is difficult to reproduce the same luminance balance, in other words, to ensure the reproducibility of the mat processing result at a high level. As described above, depending on the mat processing method such as blasting, it is difficult to uniformly and efficiently process the end face of the flat plate material serving as the light guide plate into a rough surface having a light diffusion shape of an appropriate size.
[0008]
Also, in the method of forming continuous projections on the end face of a flat plate by cutting, generally an end mill having a plurality of blades is used, but depending on the state of polishing of the blade, from the center of rotation of the end mill to the cutting surface Is slightly different for each blade, and an unintended striped pattern may occur on the processed surface. On the other hand, when a single-edged end mill is used, the machining state varies depending on the blade, but the machining takes time because the number of blades is small. In addition, as shown in FIG. 10, the end face of the flat plate 9a is cut while moving the end mill (its locus is indicated by a two-dot chain line t) in the direction indicated by the arrow D, and the valleys continuous with the end face of the flat plate 9a. When 9b is formed, the pitch p of the valleys 9b may vary due to mechanical wrinkles unique to the processing machine related to the feed of the end mill. As described above, it is difficult to uniformly and efficiently process the end face of the flat plate material to be the light guide plate into a desired shape even by the conventional cutting method.
[0009]
On the other hand, in the resin molding method using a mold, a large number of reflection dots 7 for diffusing light are formed on the reflective surface opposite to the light output surface of the light guide plate 1, so that it is substantially perpendicular to the reflective surface. If the light incident end face is also provided with a light diffusing shape, a fine but undercut will occur in the mold cavity used for the resin molding. For this reason, it is necessary to perform an ejector operation by forcibly removing or use a mold in which the cavity surface forming the light incident end face is a side slider type, but PMMA which is a resin material used for manufacturing a light guide plate Since the material is a resin material that is hard, brittle and excellent in fluidity, new problems such as loss of finely shaped parts or generation of resin burrs due to resin flowing into the gaps of the sliding cavity parts Will cause. In addition, as the size of the valley shape or wave shape here, it is required that the height is several μm and the pitch is 10 μm to 20 μm, so that it is used for processing of cavity parts of molds used in resin molding. Requires advanced processing technology, expensive equipment and a great amount of processing time. For this reason, a metal mold | die becomes expensive and it also poses a problem also at the product cost side of a light-guide plate.
[0010]
The present invention has been made in view of the circumstances as described above, and is easy in the case of manufacturing a light guide plate which is one of the components of an edge light type surface light source device used in a liquid crystal display device or the like. Providing a cutting method of a flat plate end face capable of performing fine processing of a repetitive shape on the end face of a flat plate material such as plastics in a very short time, in a uniform and highly accurate manner with good reproducibility, and An object of the present invention is to provide a flat plate end face cutting device capable of suitably carrying out the method.
[0011]
[Means for Solving the Problems]
According to the first aspect of the present invention, a cutting tool having a cutting edge width equal to or greater than the thickness dimension of the flat plate material to be cut is opposed to the cutting end surface of the flat plate material to be cut, and the cutting tool and the flat plate material are cut. In a cutting method of a flat plate end face, which is relatively moved along the longitudinal direction of the cut end face of the cut flat plate and cuts the cut end face of the flat cut plate along the longitudinal direction, the cutting tool is cut. While vibrating in the direction orthogonal to the cut end face of the flat plate material, the bite is moved at an arbitrary speed relative to the flat plate material to be cut (for example, the vibration frequency is almost constant depending on the mass and amplitude of the blade and is currently used at 37 KHz. However, it is moved at a speed that is dependent on the vibration frequency, etc., and wave-like fine irregularities in the longitudinal direction of the cut end surface are repeatedly formed on the cut end surface of the flat plate material to be cut. Features forming To.
[0012]
The invention according to claim 2 has a flat plate material holding means for holding a flat plate material to be cut, a cutting edge width equal to or greater than the thickness dimension of the flat plate material to be cut, and the cut end surface of the flat plate material to be cut is A cutting tool cut along the longitudinal direction, a cutting tool holding means for holding the cutting tool so as to face the cut end surface of the flat plate material to be cut held by the flat plate material holding means, and held by the cutting tool holding means. A feed mechanism that relatively moves the cutting flat plate held by the cutting tool and the flat plate holding means along the longitudinal direction of the cut end face of the cutting flat plate. In the cutting apparatus, the cutting tool is provided with a cutting tool vibrating means that vibrates the cutting tool in a direction orthogonal to the cutting end surface of the flat plate material to be cut, and is applied to the flat plate material to be cut by the feed mechanism while vibrating the cutting tool. Are relatively moved, to the work end surface of the cutting flat material, the corrugated fine irregularities in plan view, characterized in that it has to be repeatedly formed in the longitudinal direction of the work end surface.
[0013]
According to a third aspect of the present invention, in the cutting device according to the second aspect, the first bit and the second bit are arranged in parallel by providing an interval in a direction along the longitudinal direction of the cut end face of the flat plate material to be cut. The cutting tool of the cutting tool of the first cutting tool is disposed slightly behind the cutting edge of the flat plate material to be cut from the cutting tool of the second cutting tool. It is characterized by the fact that it has been made a byte.
[0014]
According to a fourth aspect of the present invention, in the cutting apparatus according to the second or third aspect, the cutting tool vibrating means is an ultrasonic vibrator.
[0015]
According to the method for cutting a flat plate end face according to the first aspect of the present invention, the cutting tool is vibrated in a direction orthogonal to the cut end face of the cut flat plate material while being relatively arbitrary along the longitudinal direction of the cut end face. By moving at a speed, as shown in FIG. 7, the tip of the cutting edge of the cutting tool 160 draws a trajectory T corresponding to a sine wave S when the flat plate to be cut is viewed in plan view. The cutting end face is cut along the longitudinal direction (the arrow C in FIG. 7 indicates the moving direction of the cutting tool 160). For this reason, on the cut end surface of the flat plate material to be cut, fine irregularities having a wave shape with a height (depth) corresponding to the amplitude a of the cutting tool 160 in a plan view are repeatedly and stably formed in the longitudinal direction of the cut end surface. Will be. Further, since the value obtained by dividing the moving speed of the cutting tool 160 by the frequency becomes the pitch P of the fine unevenness formed on the cut end surface of the flat plate material to be cut, the moving speed and the vibration frequency of the cutting tool 160 are set constant. In addition, when it is desired to change the pitch P of the fine irregularities in the middle, the fine irregularities can be reproduced on the cut end face of the flat plate material as desired by appropriately changing the moving speed of the cutting tool 160. It becomes possible to process and form well.
[0016]
In the cutting apparatus for the flat plate end face according to the second aspect of the present invention, the cutting tool held by the cutting tool holding means by the cutting tool vibrating means is applied to the cutting end surface of the flat plate material to be cut held by the flat plate holding means. While being vibrated in a direction orthogonal to each other, the feed mechanism relatively moves the cutting tool and the flat plate material to be cut along the longitudinal direction of the cut end surface of the flat plate material to be cut. Thus, the cutting plate material is cut as described above by relatively moving along the longitudinal direction of the cutting end surface while the cutting tool vibrates in the direction orthogonal to the cutting end surface of the cutting plate material. On the cut end face, wavy fine irregularities having a height (depth) corresponding to the amplitude of the cutting tool in plan view are repeatedly and stably formed in the longitudinal direction of the cut end face. Further, by appropriately controlling the feed mechanism and the tool vibration means so that the moving speed and the vibration frequency of the tool are respectively constant, and when it is desired to change the pitch P of the fine irregularities on the way, By controlling the feed mechanism so as to appropriately change the moving speed, it becomes possible to process and form fine irregularities on the cut end surface of the flat plate material to be cut as desired with high reproducibility.
[0017]
In the cutting device according to the third aspect of the present invention, after the cut end face of the flat plate to be cut is cut into a flat shape by the first cutting tool, the flat surface cut by the first cutting tool is continuously cut by the second cutting tool. Then, fine irregularities are formed on the cut end surface of the flat plate material to be cut.
[0018]
In the cutting device according to the fourth aspect of the invention, the amplitude of the ultrasonic transducer is amplified, and the tool bit vibrates with the amplified amplitude, so that a wave having a height (depth) corresponding to the amplified amplitude is obtained. Fine irregularities of the shape are repeatedly formed in the longitudinal direction of the cut end surface.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the present invention will be described below with reference to FIGS.
[0020]
1 to 4 show an example of an embodiment of the present invention. FIG. 1 is a perspective view of a cutting device for a flat plate end face, and is a partially broken view, and FIG. 3 is a sectional view taken along the line III-III in FIG. 2, and FIG. 4 is a sectional view showing a part of FIG. 3 in an enlarged manner. This end face cutting apparatus is used, for example, for cutting an end face of a light guide plate that is a component part of a backlight unit of a liquid crystal display device.
[0021]
In this end face cutting apparatus 10, a base plate 16 is horizontally fixed to the upper ends of a pair of support plates 14, 14 suspended from the upper surface of a gantry 12, and a workpiece fixing unit 18 is attached to one half of the base plate 16. And the cutting unit 20 is arranged in the other half. The drive of the cutting unit 20 is controlled by the control panel 22 disposed below the base plate 16, and the end surface 26 of the flat resin molded plate 24 fixed to the work fixing unit 18 is cut by the cutting unit 20. Process.
[0022]
As shown in FIG. 3, the workpiece fixing unit 18 includes a clamper vertical cylinder 28 fixed to the upper surface of the gantry 12 at a position directly below the center of the base plate 16. A bracket 32 is attached to the upper end of the piston 30 of the cylinder 28. A shaft 34 is erected on each side of the bracket 32, and a clamper 36 is bridged between the upper ends of the pair of left and right shafts 34. The shaft 34 is inserted through a bush 38 fixed to the base plate 16 and supported so as to be slidable in the vertical direction.
[0023]
As shown in FIGS. 2 and 3, a long hole 40 for dropping chips is formed in the approximate center of the base plate 16. A receiving tray 42 is disposed below the long hole 40 of the base plate 16. One end of a dust collecting pipe 44 is connected to the receiving tray 42, and the other end of the dust collecting pipe 44 is connected to a dust collector 46. . On the other hand, on the upper surface side of the base plate 16, a processing support base 48 is fixed to one side edge portion of the long hole 40. As shown in FIG. 4, a clamp base 52 is fixed to a stepped portion 50 formed on the upper edge of the processing support base 48. In addition, a static eliminator 56 is attached to the clamper 36 via a bracket 54 fixed to the upper end portion thereof, and a nozzle 58 for blowing static elimination air is connected to the static eliminator 56. Further, a manifold 62 connected to an air blow supply pipe 60 attached to the clamper 36 is attached to the clamper 36 so as to be disposed below the nozzle 58.
[0024]
A cylinder 64 is fixed on the upper surface of the base plate 16 at a position adjacent to the processing support 48. The upper end portion of the piston 66 of the cylinder 64 is connected to a connecting portion 70 integrally formed with a processing reference plate 68 that slides in the vertical direction along the front surface of the processing support 48 facing the cutting unit 20. Yes. Then, by driving the cylinder 64, the connecting portion 70 connected to the piston 66 moves up and down in a recess 72 formed at the center of the side surface of the processing support base 48, and is integrally formed with the connecting portion 70. The processed reference plate 68 is slid in the vertical direction. The clamp table 52 is fixed at a position where the front surface facing the cutting unit 20 is slightly retracted so that it does not interfere with the processing reference plate 68. Therefore, the processing reference plate 68 slides with reference to the front surface of the processing support 48 facing the cutting unit 20. Further, the processing reference plate 68 can be smoothly moved in the vertical direction via a pair of left and right slide bearings 74 that respectively support the connecting portions 70 on both sides thereof.
[0025]
As shown in FIGS. 1 and 3, a cutting plate support table 76 is disposed behind the processing support table 48 on the back side, and a longitudinal positioning cylinder 78 is provided on the cutting plate support table 76. Is fixed. In addition, a clamp table 80 is fixed on the work plate support table 76, and the position of the clamp table 80 is adjusted so that its upper surface is flush with the upper surface of the clamp table 52 of the processing support table 48. Has been. The cylinder 78 includes a piston 82 that passes through the clamp base 80 and can be taken in and out in the horizontal direction. A positioning contact plate 84 is fixed to the tip of the piston 82. Further, as shown in FIGS. 1 and 2, a left / right (cutting direction) positioning cylinder 86 is disposed on the base plate 16, and a positioning contact plate is disposed at the tip of a piston 88 of the cylinder 86. 90 is fixed. On the base plate 16, a block 92 for positioning in the left-right direction (cutting direction) is disposed on the opposite side of the cylinder 86 in the cutting direction.
[0026]
As shown in FIGS. 3 and 4, the cutting unit 20 includes a bracket 94 disposed at a position facing the processing support base 48 with the long hole 40 of the base plate 16 therebetween. The bracket 94 is substantially L-shaped in cross section, and three sets of slide bearings 96 are arranged side by side on the lower surface side. The bracket 94 has a pair of support plates 98 and 98 on both left and right sides thereof, and both ends of the ball screw shaft 100 are supported by the pair of support plates 98 and 98 so as to be rotatable. Yes. The ball screw shaft 100 is connected to a servo motor 104 through a coupling 102. A tool post 106 is screwed onto the ball screw shaft 100, and an ultrasonic cutting tool 112 having a first cutting tool 108 and a second cutting tool 110 attached to the tip thereof is held by the tool rest 106. Has been. Further, the tool post 106 is engaged with the inward surface side of the bracket 94 via a slide bearing 114, and is supported so as to be movable in the cutting direction (the direction along the ball screw shaft 100).
[0027]
As shown in the perspective view of FIG. 5, the ultrasonic cutting tool 112 includes a substantially cylindrical tool main body 116, a Langevin type ultrasonic vibrator 118 fixed to the inside of the tool main body 116 by bolting, The cutting tool mounting portion 120 provided at the tip of the sound wave vibrator 118 and having a mounting surface that is positioned by contacting the bottom surface and two side surfaces of the cutting tool tip, and the cutting tool mounting portion 120 are detachably attached. It consists of a second byte 110 of the exchange chip type. In the ultrasonic cutting tool 112 having such a configuration, the vibration direction A of the ultrasonic vibration coincides with the axial direction of the cylindrical tool main body 116. Then, due to the resonance action of the ultrasonic transducer 118, the direction of the amplitude of the sub-μm is aligned in a constant direction, the amplitude is stably amplified to several μm, and the height (depth) corresponding to the amplified amplitude. It is possible to form the corrugated fine irregularities on the end face 26 of the resin molding plate 24. Further, since the second cutting tool 110 is of the exchange chip type, the mounting and removal of the second cutting tool 110 can be facilitated, and the work setup time can be shortened. Note that an arrow B in FIG. 5 indicates the moving direction of the ultrasonic cutting tool 112. Reference numeral 122 denotes a cable connecting portion.
[0028]
The first cutting tool 108 is constituted by, for example, a cutting blade made of high-speed steel, and the cutting blade is arranged slightly rearward with respect to the end surface 26 of the resin molding plate 24 with respect to the cutting blade of the second cutting tool 110. As a material for the cutting blade of the second cutting tool 110, natural diamond, artificial diamond, nitride material (borazone), or the like is used. Further, the respective cutting edge widths of the first cutting tool 108 and the second cutting tool 110 are equal to or larger than the thickness dimension of the resin molding plate 24, and the entire thickness direction of the end face 26 is continuously formed by one cutting. It can be cut.
[0029]
Near the rear edge of the upper surface side of the base plate 16, a driving support base 124 is disposed as shown in FIGS. 2 to 4, and a pair of ball screw shafts 126 are provided on the left and right sides of the driving support base 124. Are rotatably held via bearings 128, respectively. The protruding tip portions of the pair of ball screw shafts 126 are screwed into the brackets 94, respectively, and the ball screw shaft 126 is rotated so that the bracket 94 reciprocates on the base plate 16 in the front-rear direction. It has become. Further, the bracket 94 and the driving support base 124 are connected by a pair of left and right springs 130, 130 and are urged by these springs 130 toward each other to prevent the backlash of the ball screw shaft 126. It has come to be. A timing pulley 132 is fixed to each rear end of the pair of ball screw shafts 126 protruding from the driving support base 124. Further, a pulse motor 136 is attached to a bracket 134 fixed near the rear end edge of the lower surface side of the base plate 16, and a timing pulley 138 fixed to the rotation shaft of the pulse motor 136 and a pair of ball screw shafts 126. The timing belt 140 is wound around the timing pulleys 132 and 132 fixed to the rear end portions.
[0030]
Further, as shown in FIG. 4, an air guide 142 having a substantially L-shaped cross section is attached to the base plate 16 on the front end surface facing the processing support base 48. Further, the tool post 106 is provided with a scattering prevention plate 144 on its inward end surface. Chips of the resin molded plate 24 fall into a region partitioned by the air guide 142 and the scattering prevention plate 144 and the processing reference plate 68. For this reason, the chips are prevented from scattering to the outside, and the chips are prevented from adhering to the surface of the resin molding plate 24 and damaging the resin molding plate 24. In addition, the code | symbol 146 in FIG. 1 shows an operation box.
[0031]
Next, an operation method of the end face cutting apparatus 10 having the above-described configuration will be described. First, the cutting conditions for the depth of cut with respect to the end surface 26 of the resin molding plate 24 and the cutting speed (moving speed of the cutting tools 108 and 110) are input to the control panel 22. As for the cutting speed, for example, if the resonance frequency of the ultrasonic cutting tool 112 is 37 kHz, when the pitch of the corrugated fine irregularities to be processed is 10 μm, the feed amount of the cutting tools 108 and 110 is 3700 Hz × 0.01 mm = Since it is 370 mm / sec, it is set to 370 mm per second. Then, the resin molding plate 24 is placed on the clamp bases 52 and 80, and the end surface 26 as a processing surface is abutted against the processing reference plate 68. Next, the front-rear direction positioning cylinder 78 is driven, and the resin molding plate 24 is pressed by the positioning contact plate 84 fixed to the tip of the piston 82, so that the end surface 26 of the resin molding plate 24 is moved to the processing reference plate 68. And the lateral positioning cylinder 86 is driven, and the resin molding plate 24 is pressed by the positioning contact plate 90 fixed to the tip of the piston 88 to position the side end surface of the resin molding plate. Pressure contact with the block 92. Subsequently, the clamper up / down cylinder 28 is driven, the clamper 36 is lowered, and the clamper 36 and the clamp base 52 clamp the vicinity of the edge portion 26 of the resin molding plate 24. Next, the end face 26 of the resin molding plate 24 is exposed by driving the cylinder 64 and lowering the processing reference plate 68.
[0032]
When the positioning and fixing of the resin molding plate 24 is finished, the pulse motor 136 is driven and the ball screw shafts 126 and 126 are rotated via the timing pulleys 132 and 138 and the timing belt 140, whereby the tool post 106 is moved to the resin molding plate 24. Then, the tool post 106 is positioned at a predetermined cutting start position. At this time, the backlash is removed by the spring force of the springs 130 and 130. For this reason, the cutting position can be accurately set by controlling the feed amount of the tool post 106 in units of 1 μm, for example.
[0033]
Next, the ultrasonic cutting tool 112 is operated, the servo motor 104 is driven, and the ball screw shaft 100 is rotated via the coupling 102, whereby the tool post 106 is linearly moved in the cutting feed direction. By this operation, the end face 26 of the resin molding plate 24 is cut into a flat shape by the first cutting tool 108, and the cut flat surface is continuously cut by the second cutting tool 110 of the ultrasonic cutting tool 112, and resin molding is performed. Wave-shaped fine irregularities are processed and formed on the end face 26 of the plate 24. Chips of the resin molded plate 24 generated at this time are blown downward by the discharging air blown out from the nozzle 58 and the manifold 62 connected to the discharging device 56, and flow into the receiving tray 42 through the long hole 40. The dust is collected in the dust collector 46 through the dust collecting pipe 44.
[0034]
In this end face cutting apparatus 10, the tool post 106 is slid by rotating the ball screw shaft 100. For this reason, it is easy to move the tool post 106 at a constant speed, and the cutting depth by the ultrasonic vibration of the ultrasonic cutting tool 112 is also stabilized by the resonance operation, so that the finishing accuracy becomes uniform. There is an advantage.
[0035]
When the tool rest 106 moves to a predetermined position, the tool rest 106 is moved away from the resin molding plate 24 by driving the pulse motor 136 to rotate in the reverse direction. Then, the tool post 106 is returned to the original position by driving the servo motor 104 to rotate in the reverse direction.
[0036]
When the cutting of the end face 26 of the resin molded plate 24 is completed, the clamper vertical cylinder 28 is driven to raise the clamper 36, and the clamped state of the resin molded plate 24 by the clamper 36 and the clamp base 52 is released. Then, after the pistons 82 and 88 of the positioning cylinders 78 and 86 are pushed out to separate the positioning contact plates 84 and 90 from the resin molding plate 24, the resin molding plate 24 is taken out from the clamp bases 52 and 80. The processing work is finished.
[0037]
In the above-described cutting operation, the cutting tools 108 and 110 are fed at a constant speed in the cutting direction. However, in the case described below, the cutting tools 108 and 110 are not set at a constant feed.
[0038]
As problems other than the dark band of the liquid crystal display device, for example, as shown in FIG. 6, the liquid crystal display is affected by the influence of the electrode portions 154 a and 154 b of the rod-shaped light source 152 such as a cold cathode tube installed adjacent to the light guide plate 150. There is a tendency that dark portions 158 tend to appear at corners near the electrode portions 154a and 154b in the effective screen 156 of the apparatus. As a countermeasure, it can be considered that the density of the corrugated fine irregularities cut on the end face of the light guide plate 150 is changed in a region near the electrode portions 154a and 154b of the rod-shaped light source 152. That is, the cutting tool for cutting the regions Z1 and Z2 so that the corrugated fine irregularities are formed in a relatively dense state in the predetermined regions Z1 and Z2 at both ends of the end face of the light guide plate 150. The moving speeds of 108 and 110 are slowed down, and in the other region Z3, the bites 108 and 110 when cutting the region Z3 are formed so that corrugated fine irregularities are formed in a relatively rough state. Try to move faster. Alternatively, when cutting the regions Z1 and Z2 on the end face of the light guide plate 150, the cutting depth Y (unit of several tens of μm) of the cutting tools 108 and 110 is adjusted to be inclined to the end face as shown by broken lines in FIG. When cutting the other region Z3, two-dimensional linear interpolation control is performed so that fine irregularities are repeatedly formed on the end face by ultrasonic vibration of the ultrasonic cutting tool 112 with a constant cutting reference depth. It is also possible to perform. It is also possible to perform cutting by simultaneously controlling the change of the moving speed and the change of the cutting depth.
[0039]
Further, in a relatively small liquid crystal display device, instead of a cold cathode tube light source, an LED arranged in series may be used as a light source. In this case, since the luminance of the light source is not continuous, the light diffusion shape of the light incident end face of the light guide plate is set between the vicinity of the LED and the LED as a countermeasure similar to the case in the generation of the dark part due to the influence of the light source electrode part. It is required to be different depending on the position. In the conventional machining method, such a request could not be satisfied. However, if this end face cutting apparatus 10 is used, an arbitrary movement position and an arbitrary movement speed during one movement of the cutting tool 110 are set in advance. Since each can be set and controlled, it is possible to easily process the corrugated fine irregularities on the light incident end face of the light guide plate into different shapes in the vicinity of the LED and the position between the LEDs. It becomes possible.
[0040]
In the above-described embodiment, the cutting process of the end face of the light guide plate constituting the backlight of the liquid crystal display device has been described. However, the present invention is not limited to such an application, and the present invention is not limited thereto. Needless to say, the present invention can be applied to processing of other uses, for example, processing of plastic optical parts, and the like without departing from the gist of the present invention.
[0041]
【The invention's effect】
An edge light type surface light source used for a liquid crystal display device or the like by the method for cutting an end surface of a flat plate according to the invention of claim 1 and using the cutting device for an end surface of a flat plate according to the invention of claim 2. When manufacturing a light guide plate, etc., which is one of the components of the device, it is easy and extremely short in time, and is uniform, highly accurate and with good reproducibility. Unevenness can be repeatedly formed in the longitudinal direction of the cut end face. This end face cutting apparatus has a relatively simple configuration, so that the cost for the apparatus is small, and the processing time is extremely short, so that the manufacturing cost of the light guide plate and the like is significantly reduced. It becomes possible. Furthermore, the pitch of the fine irregularities can be arbitrarily changed with respect to an arbitrary region on the cut end face by appropriately changing the moving speed of the cutting tool while cutting the cut end face of the flat plate material to be cut. Is possible.
[0042]
In the end face cutting apparatus of the invention according to claim 3, since the end face of the flat plate material is cut into a flat shape by the first bite, and then the corrugated fine irregularities are cut by the second bite, the end face of the flat plate material In addition, the corrugated fine irregularities can be more accurately formed.
[0043]
In the end face cutting apparatus according to the fourth aspect of the present invention, corrugated fine irregularities having a desired height (depth) can be accurately formed on the end face of the flat plate material to be cut.
[Brief description of the drawings]
FIG. 1 shows an example of an embodiment of the present invention, and is a perspective view of a cutting device for a flat plate end face, with a part broken away.
FIG. 2 is a plan view of the end face cutting apparatus shown in FIG.
3 is a cross-sectional view taken along arrow III-III in FIG.
4 is an enlarged cross-sectional view of a part of FIG.
FIG. 5 is a perspective view showing a configuration example of an ultrasonic cutting tool which is one of the components of the end face cutting apparatus shown in FIGS. 1 to 4;
FIG. 6 is a view for explaining a modification of the operation method of the end face cutting device according to the present invention.
FIG. 7 is a view for explaining the operation of the flat plate end face cutting apparatus according to the present invention;
FIG. 8 is an exploded perspective view showing a configuration example of an edge light type surface light source device used in a liquid crystal display device.
9 is a schematic side view for explaining the operation and conventional problems in the edge light type surface light source device shown in FIG.
FIG. 10 is a diagram for explaining a problem in a conventional cutting method.
[Explanation of symbols]
10 End face cutting machine
16 Base plate
18 Work fixing unit
20 Cutting unit
24 Flat resin molded plate
26 End face of resin molded plate
28 Clamper cylinder
32, 94 Bracket
34 Shaft
36 Clamper
40 long hole
44 Dust collection pipe
46 Dust collector
48 Machining support base
52, 80 Clamp stand
56 Static eliminator
58 Nozzle for discharging static electricity
62 Manifold
64 cylinders
68 Machining reference plate
74, 96, 114 Slide bearing
76 Workpiece plate support
78 Longitudinal positioning cylinder
84, 90 Contact plate for positioning
86 Left-right direction (cutting direction) positioning cylinder
92 Left-right direction (cutting direction) positioning block
98 Support plate
100, 126 Ball screw shaft
104 Servo motor
106 turret
108 1st byte
110 2nd byte
112 Ultrasonic cutting tool
118 Ultrasonic transducer
124 Support base for driving
130 Spring
132, 138 Timing pulley
136 Pulse motor
140 Timing belt

Claims (4)

A cutting tool having a cutting edge width equal to or larger than the thickness dimension of the flat plate material to be cut is opposed to the cutting end surface of the flat plate material to be cut. In the cutting method of the flat plate end face that moves relatively along the longitudinal direction and cuts the cut end face of the cut flat plate along the longitudinal direction,
While vibrating the cutting tool in a direction orthogonal to the cutting end surface of the flat plate material to be cut, moving the cutting tool at an arbitrary speed relative to the flat plate material to be cut, to the cutting end surface of the flat plate material to be cut, A cutting method for a flat plate end face, characterized by repeatedly forming corrugated fine irregularities in plan view in the longitudinal direction of the end face to be cut. Flat plate material holding means for holding a flat plate material to be cut;
A cutting tool having a cutting edge width equal to or greater than the thickness dimension of the flat plate material to be cut, and cutting the cut end surface of the flat plate material along the longitudinal direction thereof,
A cutting tool holding means for holding the cutting tool so as to face the cut end face of the cut flat plate held by the flat plate holding means;
A feed mechanism that relatively moves the cutting tool held by the cutting tool holding means by the cutting tool held by the cutting tool holding means and the flat plate holding means;
In the cutting device of the flat plate end face provided with
A cutting tool is provided that has a cutting tool vibrating means that vibrates the cutting tool in a direction orthogonal to the cutting end surface of the flat plate material to be cut. An apparatus for cutting a flat plate end face, wherein the cut end face of the flat plate is repeatedly formed with corrugated fine irregularities in a longitudinal direction of the cut end face in a plan view. A first bit and a second bit are arranged in parallel at intervals along the longitudinal direction of the cut end face of the flat plate material to be cut, and the cutting edge of the first bit is used to cut the second bit The flat plate material end face cutting device according to claim 2, wherein the cutting tool is disposed slightly behind the cutting end surface of the flat plate material to be cut from the blade, and the second cutting tool is a cutting tool provided with the cutting tool vibration means. 4. The cutting apparatus for a flat plate end face according to claim 2, wherein the cutting tool vibrating means is an ultrasonic vibrator.

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