JP2013186975A - Manufacturing method of optical sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method and a manufacturing device for an optical sheet capable of achieving quality improvement of a product using the optical sheet, by restraining occurrence of stripes and unevenness on a processed surface in applying a dot-pattern process on a rear surface of the optical sheet.SOLUTION: In a manufacturing method of an optical sheet which irradiates laser to a rear surface of an original plate in the optical sheet having a side surface formed with an incident surface on which light emitted from a light source is incident and a surface formed with an emission surface of incident light, a non-processed surface of the original plate 60 is sucked and stuck fast in forming a dot pattern by irradiation of laser to preclude warping and lateral misalignment.

Description

  The present invention relates to an optical sheet, a method and apparatus for manufacturing the same, a surface light source device and a transmission type image display apparatus using the optical sheet.

  As a backlight used as a surface light source device of a liquid crystal display (transmission type image display device), a so-called direct type and an edge light type are known. Among these, the direct type surface light source device arranges light sources such as cold cathode tubes and LEDs on the back side of the light guide plate, and emits light incident from the back side of the light guide plate to the front side.

  One edge light type surface light source device arranges light sources such as cold-cathode tubes and LEDs on the side surface of a light guide plate which is a transparent plate, and emits light incident from the side surface of the light guide plate to the front side. As a conventional backlight, a direct type surface light source device is often used from the viewpoint of increasing the luminance. However, in recent years, the use of thin and high-brightness LED light sources has increased, and the use ratio of edge light type surface light source devices has increased with the thinning of liquid crystal displays.

  In the light guide plate in such an edge light type surface light source device, a dot pattern is formed on the back surface so that light incident from the side surface is diffusely reflected on the back surface and emitted from the front surface. As a method of applying a dot pattern to the back surface of the light guide plate, a method by screen printing is known (for example, see Patent Document 1). However, in the method of applying a dot pattern by screen printing, it is necessary to prepare an individual plate for each pattern. For this reason, the screen printing has a problem that the degree of freedom is low.

  On the other hand, dot pattern processing using laser irradiation is known as a method other than screen printing (see, for example, Patent Document 2). By using laser irradiation, it is not necessary to prepare a large number of plates, so that the degree of freedom can be increased so that even if the printing pattern is diversified.

JP 7-49421 A JP 2000-66029 A

  Incidentally, in recent years, a surface light source device using this type of light guide plate has been required to have high accuracy, for example, 150 dpi or more.

  In recent years, liquid crystal display devices have been applied to televisions and the like, and there is a tendency for light guide plates to be increased in size and thickness. In manufacturing the light guide plate, it is ideal that the light guide plate original plate has a plate shape without warping. However, in actuality, warpage or deflection occurs due to moisture absorption or uneven heating during storage. With the increase in size and thickness of the light guide plate, it is assumed that the influence of such warpage becomes significant.

  However, for the light guide plate disclosed in Patent Document 2, the demand for high definition and the demand for improving warpage of the light guide plate original plate are not high. For this reason, in the light guide plate using the dot pattern processing disclosed in Patent Document 2, when the dot pattern is formed, the processing surface is streaked due to the unevenness of the inter-dot distance and the disorder of the dot shape. Sometimes I could see unevenness. If streaks appear on the printing surface in this way, there is a problem that the quality of a liquid crystal display using an optical sheet is deteriorated.

  Accordingly, an object of the present invention is to improve the quality of a product using an optical sheet by suppressing the occurrence of streaks and unevenness on the processed surface when performing dot pattern processing on the back surface of the optical sheet. It is providing the manufacturing method and manufacturing apparatus of a sheet | seat.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a surface light source device and a transmissive image display device including an optical sheet with improved quality by reducing the risk of occurrence of streaks and unevenness on the processing surface when the dot pattern processing is performed on the back surface. Is to provide.

  The present invention that has solved the above problems irradiates a laser on the back surface of an original sheet in an optical sheet in which an incident surface for incident light emitted from a light source is formed on the side surface, and an outgoing surface for incident light is formed on the surface. A method of manufacturing an optical sheet on which a dot pattern is formed to form a dot pattern, wherein when performing dot pattern processing, the non-processed surface of the original plate is sucked and adsorbed to eliminate warpage and lateral deviation. A manufacturing method is provided.

  Generally, when forming a low-definition dot pattern, even if warpage or lateral displacement of the plate occurred during transfer of the original plate, there was almost no streaking or unevenness in the processed pattern, so the original plate was transferred without being fixed. . However, when forming a high-definition dot pattern, streaks or unevenness of the plate may occur if warping or lateral displacement of the plate occurs during transport of the original plate, resulting in a decrease in product quality due to the stripe or unevenness. A problem occurred. In addition, the engraving depth as set could not be realized due to warpage or lateral displacement of the plate during conveyance of the original plate, resulting in a problem that the performance deteriorated in optical characteristics.

  In this regard, in the method for manufacturing an optical sheet according to the present invention, the non-processed surface of the original plate, which performs dot pattern processing, is sucked and adsorbed to eliminate lateral displacement and warpage. Suction and adsorption of the non-processed surface of the original plate to eliminate warpage and lateral misalignment, thereby suppressing the occurrence of streaks and unevenness on the processed surface of the dot pattern formation on the optical sheet and realizing the engraving depth as set. Can do. Therefore, it is possible to improve the quality of products using the optical sheet and the optical characteristics. A non-processed surface is a surface opposite to the processed surface.

  An original plate used for an optical sheet such as a light guide plate is rarely completely flat and often slightly warps. In addition, lateral misalignment may occur during conveyance of the original plate. Due to the influence of the warp and the lateral shift, there is a concern about the occurrence of streaks and unevenness on the processed surface. In this regard, when performing dot pattern processing, the non-processed surface of the original plate is sucked and adsorbed to eliminate warpage, thereby more reliably suppressing the occurrence of streaks and unevenness on the dot pattern processed surface, and engraving as set. Depth can be realized. As a result, it is possible to further improve product quality and optical characteristics using the optical sheet.

  Furthermore, it can be set as the aspect whose thickness of an original plate is 4.5 mm or less.

  Moreover, it can be set as the aspect whose length L of the diagonal of an original plate is 500 mm or more.

ただし、Ｌは、原板の対角線の長さ（ｍｍ）、Ｔは、原板の厚み（ｍｍ）である。 It is preferable that the length L and the thickness T of the diagonal line of the original plate satisfy the following formula (1).

However, L is the length (mm) of the diagonal of the original plate, and T is the thickness (mm) of the original plate.

  Further, it is preferable that the dot density of the dot pattern applied to the original plate is 150 dpi or more.

  Thus, it is preferable that the thickness of the original plate is adjusted to 4.5 mm or less. Further, it is more preferable that the thickness of the original plate is adjusted to 2.0 mm or less.

  An optical sheet manufactured by the method for manufacturing an optical sheet may be used, or a surface light source device including a light source disposed on the side of the incident surface of the optical sheet. Furthermore, a transmissive image display device is provided that includes the surface light source device, is disposed to face the light exit surface of the optical sheet, and includes a transmissive image display unit that displays an image by being irradiated with light emitted from the light source. You can also.

  On the other hand, in the present invention that has solved the above problems, an incident surface for incident light emitted from a light source is formed on the side surface, an exit surface for incident light is formed on the surface, and a laser is irradiated on the rear surface to form a dot pattern. An optical sheet manufacturing apparatus that manufactures an optical sheet subjected to dot pattern processing formed by the optical sheet, and when performing dot pattern processing, the non-processed surface of the original plate is sucked and adsorbed to eliminate warpage and lateral misalignment. A sheet manufacturing apparatus is provided.

  According to the manufacturing method and the manufacturing apparatus of the optical sheet according to the present invention, when dot pattern processing is performed on the back surface of the optical sheet, by suppressing the occurrence of streaks and unevenness on the processing surface, Quality can be improved.

  According to the surface light source device and the transmissive image display device according to the present invention, the processing surface when the dot pattern processing is performed on the back surface is provided with an optical sheet with reduced risk of occurrence of streaks and unevenness and improved quality. A planar light source device and a transmissive image display device can be provided.

It is a decomposition side sectional view showing typically the transmission type image display device using the light guide plate concerning an embodiment. It is a top view which shows typically the transmissive image display apparatus using the light-guide plate which concerns on embodiment. It is a perspective view which shows the light-guide plate manufacturing apparatus which concerns on embodiment. It is a perspective view which shows a laser irradiation head. It is a side view which shows typically the relationship between the laser irradiation part at the time of performing dot pattern processing, and the original plate of a light-guide plate. It is a top view which shows the conveyance belt which mounts a light-guide plate when a dot pattern process is performed. (A) (b) is a figure showing other arrangement patterns of a processing dot. It is a perspective view which shows the 1st modification of a laser irradiation apparatus. It is a perspective view which shows the 2nd modification of a laser irradiation apparatus.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that, in each embodiment, the same elements are denoted by the same reference numerals, and redundant description may be omitted. For the convenience of illustration, the dimensional ratios in the drawings do not necessarily match those described.

  In the present invention, the dot pattern processing in the method of manufacturing a light guide plate, which is an optical sheet in a surface light source device used in a transmissive image display device such as a liquid crystal display device, is mainly characteristic. In the present embodiment, first, the structure of a liquid crystal display device including a light guide plate will be described, and subsequently, dot pattern processing in the method of manufacturing the light guide plate will be described.

  FIG. 1 is an exploded side sectional view schematically showing a liquid crystal display using the light guide plate according to the first embodiment of the present invention, and FIG. 2 is a rear view thereof. As shown in FIG. 1, a liquid crystal display device 1 that is a transmissive image display device includes a transmissive image display unit 10 and a surface light source device 20. The surface light source device 20 is disposed on the back side of the transmissive image display unit 10 and emits light from the back side of the transmissive image display unit 10. In the following description, as shown in FIG. 1, the arrangement direction of the surface light source device 20 and the transmissive image display unit 10 is referred to as a Z direction (plate thickness direction), which is two directions orthogonal to the Z direction and orthogonal to each other. The two directions are referred to as the X direction and the Y direction.

  The transmissive image display unit 10 includes a liquid crystal cell 11 and a linear polarizing plate 12, and the linear polarizing plate 12 is disposed on both sides of the liquid crystal cell 11. As the liquid crystal cell 11 and the linear polarizing plate 12, those used in known liquid crystal display devices can be used. Examples of the liquid crystal cell 11 include known liquid crystal cells such as a TFT type and an STN type.

  The surface light source device 20 includes a light guide plate 30 that is an optical sheet and an LED light source 22. The light guide plate 30 is formed of a translucent resin that transmits light and has a plate shape. The light guide plate 30 may be a sheet or a film. Moreover, it is preferable that the thickness T of the light-guide plate 30 is 1.0 mm or more and 4.5 mm or less.

  The light guide plate 30 includes a plate-like member made of a translucent resin. The refractive index of the translucent resin is, for example, in the range of 1.49 to 1.59. As the translucent resin used for the light guide plate 30, methacrylic resin is mainly used. As the resin used for the light guide plate 30, other resins may be used, or styrene resins may be used. As the translucent resin, an acrylic resin, a styrene resin, a polycarbonate resin, a cyclic olefin resin, an MS resin (a copolymer of acrylic and styrene), or the like can be used. Furthermore, additives such as a light diffusing agent, an ultraviolet absorber, a heat stabilizer, and a photopolymerization stabilizer can be added to the light guide plate 30.

  The light guide plate 30 has a rectangular parallelepiped shape, and includes a front surface 31 and a rear surface 32 which are a pair of main surfaces facing each other in the Z-axis direction (thickness direction) as shown in FIG. The light guide plate 30 includes a pair of side surfaces 33 facing in the X-axis direction and a pair of side surfaces 34 facing in the Y-axis direction. The front surface 31 and the back surface 32 are formed in a direction intersecting with the side surfaces 33 and 34, more specifically, in a direction orthogonal to the side surfaces 33 and 34. The front surface 31, the rear surface 32, and the side surfaces 33 and 34 are all rectangular.

  Among these, the surface 31 can be a flat surface or a surface provided with irregularities. When the surface 31 is provided with irregularities, for example, a plurality of protrusions that protrude in the Z-axis direction and whose longitudinal direction extends along the X-axis direction can be arranged in parallel with each other while being separated in the Y-axis direction. . The shape of the ridge portion can be a shape in which the surface is a prism shape, and the cross-sectional shape when the ridge portion is cut in a direction orthogonal to the longitudinal direction is a semicircular shape or a semi-elliptical shape It can be. Moreover, it is preferable that the protrusions have the same cross-sectional shape when cut in a direction orthogonal to the longitudinal direction. Note that the direction in which the protrusions extend is preferably parallel to the incident direction when light emitted from the light source enters from the side surface of the light guide plate.

  The surface 31 functions as a surface that can emit planar light. The front surface 31 is disposed on the transmissive image display unit 10 side, and the back surface 32 is disposed on the opposite side of the transmissive image display unit 10. Various films 41 are disposed between the light guide plate 30 and the transmissive image display unit 10 on the front side of the light guide plate 30. Furthermore, a reflection sheet 42 that reflects the light in the light guide plate 30 toward the front surface 31 is disposed at a position facing the back surface 32. Examples of the various films 41 include a diffusion film, a prism film, and a brightness enhancement film.

  The LED light source 22 is disposed on the side of the light guide plate 30 so as to face the side surface 33 extending in the Y-axis direction of the light guide plate 30. The side surface 33 of the light guide plate 30 serves as an incident surface on which light emitted from the LED light source 22 is incident. The plurality of LED light sources 22 are discretely arranged along the longitudinal direction (Y-axis direction) of the side surface 33. Light incident from the side surface 33 of the light guide plate 30 exits from the surface 31. The surface of the light guide plate 30 serves as an emission surface that emits light incident from the side surface 33.

  The arrangement interval of the LED light sources 22 is normally 5 mm to 20 mm. The LED light source 22 is disposed along the side surface 33 facing the Y axis. Instead of this aspect, the light guide plate 30 may be disposed along each of the four sides, or may be disposed along the side surfaces 34 facing each other with the X axis interposed therebetween. Or you may arrange | position along any one side of the side surfaces 33 and 34. FIG. Further, the light source is not limited to the LED light source, but may be other light sources. Furthermore, as a light source, the structure by which linear light sources, such as a cold cathode tube, are arrange | positioned may be sufficient.

  The LED light source 22 is composed of, for example, a white LED, and a plurality of LEDs are arranged in one place to constitute one light source unit. Further, as one light source unit, LEDs of three colors of red, green, and blue may be arranged close to each other. Here, when light source units having a plurality of LEDs are discretely arranged along the arrangement direction described above, it is preferable that the LEDs of different colors be arranged as close as possible.

  As the LED light source, those having various light emission distributions can be used, but the luminous intensity in the normal direction (X-axis direction) of the LED light source is maximum, and the half-value width of the luminous intensity distribution is 40 degrees or more and 80 degrees or less. Those having a certain light emission distribution are preferred. Specific examples of the LED light source type include a Lambertian type, a shell type, and a side emission type.

  The size of the light guide plate 30 when viewed in plan is set so as to match the target screen size of the transmissive image display unit 10. Specifically, the length of two orthogonal sides is usually 250 mm × 440 mm or more (diagonal length L is 506 mm or more). Furthermore, a large size of 500 mm × 800 mm or more (diagonal length L is 943 mm or more) may be used. Or although the planar view shape of the light-guide plate 30 is made into the rectangle, it can also be set as other shapes, such as a square. In addition, the thickness T of the original plate (translucent resin sheet) of the light guide plate 30 may be 4.5 mm or less, for example, 2.0 mm or 1.0 mm.

ただし、Ｌは、原板の対角線の長さ（ｍｍ）、Ｔは、原板の厚み（ｍｍ）である。なお、対角線の長さＬは、５００ｍｍ以上である。 Further, the original plate 60 of the light guide plate 30 may satisfy the following formula (1).

However, L is the length (mm) of the diagonal of the original plate, and T is the thickness (mm) of the original plate. The length L of the diagonal line is 500 mm or more.

  Furthermore, a plurality of dots 35 are formed on the back surface 32 of the light guide plate 30. The processed dots 35 are formed by dot pattern processing using laser irradiation. The processed dots 35 are formed such that the diameter of the processed dots 35 on the back surface 32 is closer to the LED light source 22 and the diameter gradually increases as the distance from the LED light source 22 increases.

  In addition to the form shown in FIG. 2, for example, as shown in FIG. 7A, the processed dots 35 have a plurality of processed dots 35 having substantially the same size on the back side of the light guide plate 30. It can also be set as the aspect arrange | positioned by grid | lattice form. In the case where the processing dots 35 are arranged in a lattice shape, a square lattice, a triangular lattice, a cubic lattice, a hexagonal lattice, a grid lattice, or the like can be used. Alternatively, as shown in FIG. 6B, a plurality of processed dots 35 having substantially the same size can be randomly arranged. In addition, the size of the processing dots 35 can be appropriately changed in these modes.

  Then, the dot pattern process in the manufacturing method of the light-guide plate 30 is demonstrated. Dot pattern processing is performed using laser irradiation. When performing dot pattern processing using laser irradiation, a dot pattern is formed by irradiating a laser beam from a laser irradiation unit to an original plate for manufacturing the light guide plate 30.

  FIG. 3 is a perspective view showing the light guide plate manufacturing apparatus according to the embodiment. When performing dot pattern processing, a light guide plate manufacturing apparatus (optical sheet manufacturing apparatus) 200 as shown in FIG. 3 is used. The light guide plate manufacturing apparatus 200 shown in FIG. 3 includes a transport means 70 for transporting the translucent resin sheet 60 (original plate of the light guide plate 30) and a laser irradiation device 50.

  The conveying means 70 includes a conveying belt 71 on which the translucent resin sheet 60 is placed and conveyed, a pair of conveying rollers 72 for moving the conveying belt 71 (only one is shown in FIG. 3), and conveying A suction box 73 for sucking the translucent resin sheet 60 placed on the belt 71 is provided. The translucent resin sheet 60 may be described as the original plate 60.

  The conveyor belt 71 is stretched over a pair of conveyor rollers 72 and extends in the horizontal direction (direction A in the figure). The drive-side transport roller 72 is rotationally driven by a motor (not shown) to move the transport belt 71. The processing surface 60 a of the original plate 60 is directed upward, and the non-processing surface 60 b that is the surface opposite to the processing surface 60 a is disposed in contact with the conveyance belt (table) 71.

  The suction box 73 has a box shape and is disposed between the conveyor belts 71 and 71 spaced apart in the vertical direction. A plurality of suction boxes 73 are arranged along the movement direction A. The suction box 73 is connected to an evacuation unit such as a vacuum pump, for example, so that the inside of the box can be decompressed.

  FIG. 4 is a perspective view showing a laser irradiation head. The laser irradiation device 50 bends a laser traveling in the width direction B (direction B intersecting the moving direction A) above the original plate 60 and irradiates the original plate 60 with the laser irradiation head 51 and the laser irradiation head 51 as the original plate. 60, and a support unit 150 that is movably supported along the width direction B.

  The laser irradiation head 51 includes a mirror 51a that reflects the laser 54, and bends the laser 54 traveling in the width direction B of the original plate 60 downward. The laser irradiation head 51 is provided with a laser irradiation unit 52 that irradiates the laser 54 toward the original plate 60. The laser 54 emitted from the laser irradiation unit 52 is applied to the original plate 60.

  The support unit 150 includes a drive mechanism such as a rack and pinion, for example, and moves the laser irradiation head 51 to a predetermined position in the width direction B of the original plate 60. The support unit 150 may include other drive mechanisms such as a ball screw, and may move the laser irradiation head 51 to a predetermined position.

  FIG. 5 is a side view schematically showing a relationship between a laser irradiation unit and a light guide plate when performing dot pattern processing. The laser irradiation head 51 is provided with one or a plurality of laser irradiation units 52 (for example, laser irradiation nozzles). FIG. 6 is a diagram illustrating a conveyance belt on which a light guide plate is placed when dot pattern processing is performed. The suction box 73 has a top plate 73a on which the transport belt 71 is placed. The outer surface of the top plate 73a forms a flat surface and forms a surface on which the conveyor belt 71 slides. Then, the translucent resin sheet 60 is placed on the transport belt 71. That is, the conveyance belt 71 functions as a table on which the original plate 60 is placed.

  The top plate 73a and the conveyor belt 71 of the suction box 73 are provided with a plurality of openings 73b and 71a. The distance between the openings 73b and 71a is, for example, about 5 cm. The shapes of the openings 73b and 71a may be other than circular. When the conveyor belt 71 is disposed at a predetermined position, the opening 71a of the conveyor belt 71 and the opening 73b of the top plate 73a coincide. When the vacuum pump unit is operated to reduce the pressure in the suction box 73, the non-processed surface 60b of the transported original plate 60 is adsorbed on the transport belt 71, and warpage and lateral displacement are eliminated. The distance between the conveying belt 71 (table) on which the original plate 60 is placed and the laser irradiation head 51 is adjusted to be equal to or less than the distance obtained by adding the thickness T of the original plate 60 to 2.8 mm, for example.

  In addition, in the light-guide plate manufacturing apparatus 200, the original plate 60 can be conveyed continuously or intermittently. Further, the table on which the original plate 60 is placed is not limited to the transport belt 71, but may be other transport trays. Further, the light guide plate manufacturing apparatus 200 may be configured not to include a conveying unit. It suffices if the original plate 60 is placed on the table and the non-processed surface 60b of the original plate 60 is sucked and adsorbed so that the warpage and lateral deviation of the original plate 60 can be eliminated.

  When performing dot pattern processing, first, the non-processed surface 60b of the original plate 60 is sucked and adsorbed to eliminate warpage and lateral displacement, and a laser is irradiated from the laser irradiation head 51 to generate the dot pattern processing unit 55.

  Here, in this embodiment, when irradiating a laser from the laser irradiation head 51, the non-processed surface 60b of the original plate 60 is sucked and adsorbed to eliminate warpage and lateral deviation, thereby fixing the original plate during conveyance. Yes. In the case of forming a low-definition dot pattern, there was almost no streaking or unevenness in the processed pattern without fixing the original plate 60 during conveyance.

  However, when forming a high-definition dot pattern, if warping or lateral misalignment occurs during conveyance of the original plate, streaks or unevenness may occur in the processing pattern, and the quality of the product may deteriorate due to the streak or unevenness. There is. In this regard, here, when performing the dot pattern processing, the non-processed surface 60b is sucked and adsorbed to eliminate warpage and lateral deviation. Thereby, it is possible to suppress the occurrence of streaks and unevenness on the processing surface of the dot pattern processing applied to the light guide plate 30, and it is possible to process a dot pattern having a dot density of 150 dpi (dots per inch) or more. Accordingly, the quality of the surface light source device 20 and the liquid crystal display device 1 using the light guide plate 30 can be improved. In the present embodiment, a cylindrical laser irradiation nozzle is provided as the laser irradiation unit 52. The laser reflected by the mirror passes through the laser irradiation nozzle and is emitted. The tip opening of the laser irradiation nozzle is a laser irradiation port. In addition, the structure which is not provided with the laser irradiation nozzle may be sufficient.

  The gap distance D for suppressing the occurrence of streaks and unevenness on the processing surface of the dot pattern processing applied to the light guide plate 30 is, for example, 2.8 mm or less. Furthermore, by setting the gap distance D to 1.8 mm or less, it is possible to more suitably suppress the occurrence of streaks and unevenness. The gap distance D is preferably small, but the lower limit of the gap distance D is set to a size that can avoid contact between the laser irradiation port 52 and the original plate 60 when performing dot pattern processing. it can. Specifically, the gap distance D can be set to 0.4 mm or more, or 0.5 mm or more. From these viewpoints, the gap distance needs to be 0.4 mm or more and 2.8 mm or less, preferably 0.5 mm or more and 1.8 mm or less, and 0.5 mm or more and 1.0 mm or less. Is more preferable.

  When performing dot pattern processing, the original plate 60 is placed on a conveyor belt 71 (table), and the distance between the laser irradiation port and the table is equal to or less than the distance obtained by adding the thickness T of the original plate 60 to 2.8 mm. It can be set as the aspect described. Thus, by taking into account the thickness 60 of the original plate, the distance D between the laser irradiation port and the original plate 60 is determined using the distance (D + T) between the table on which the original plate 60 is placed and the laser irradiation port. May be managed.

  Next, a first modification of the laser irradiation apparatus will be described with reference to FIG. A laser irradiation apparatus 50B illustrated in FIG. 8 includes a support unit 150B that supports the irradiation head 51 and a plurality of mirrors 51a to 51c that bend the laser 54. The support unit 150 </ b> B includes a first support member 151 extending in the width direction B of the original plate 60 and a second support member 152 extending in the moving direction A of the original plate 60.

  The first support member 151 is disposed above the original plate 60. The laser irradiation head 51 is provided with a plurality of wheels. The laser irradiation head 51 travels on the first support member 151 and moves in the width direction B of the original plate 60.

  The second support member 152 is disposed above the original plate 60. The second support members 152 are arranged on both sides of the original plate 60 and support the first support member 151 from both sides. The first support member 151 is provided with a plurality of wheels, and the first support member 151 is supported so as to be movable along the moving direction A of the original plate 60.

  The laser 54 emitted from the laser light source travels upward, is bent by the mirror 51b, and travels in the A direction. The laser 54 traveling in the A direction is bent by the mirror 51c and travels in the B direction. The laser 54 traveling in the B direction is bent by the mirror 51 a of the laser irradiation head 51, travels downward, and is irradiated onto the original plate 60. Thereby, the laser 54 is irradiated to the original plate 60, and the dot pattern processing is performed on the original plate 60.

  Next, a second modification of the laser irradiation apparatus will be described with reference to FIG. A laser irradiation apparatus 50C illustrated in FIG. 9 includes a support unit 150B that supports the plurality of laser irradiation units 52 and a plurality of mirrors 51a to 51d that bend the laser 54. The support unit 150 </ b> B includes a first support member 151 extending in the width direction B of the original plate 60 and a second support member 152 extending in the moving direction A of the original plate 60.

  The first support member 151 is disposed above the original plate 60. The first support member 151 supports a plurality of laser irradiation units 52. The laser irradiation unit 52 is provided with a half mirror 51 d that transmits and reflects the laser 54. Further, the laser irradiation unit 52 is provided with a shutter 52b for stopping the laser irradiation to the original plate 60. When the laser is not irradiated, the laser irradiation is stopped by closing the shutter 52b.

  The second support member 152 is disposed above the original plate 60. The second support members 152 are arranged on both sides of the original plate 60 and support the first support member 151 from both sides. The first support member 151 is provided with a plurality of wheels, and the first support member 151 is supported so as to be movable along the moving direction A of the original plate 60.

  The laser 54 emitted from the laser light source travels upward, is bent by the mirror 51b, and travels in the A direction. The laser 54 traveling in the A direction is bent by the mirror 51c and travels in the B direction. The laser 54 traveling in the B direction is bent by the half mirror 51d of the laser irradiation unit 52, travels downward, and is irradiated onto the original plate 60. Thereby, the laser 54 is irradiated to the original plate 60, and the dot pattern processing is performed on the original plate 60.

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device, 10 ... Transmission type image display part, 11 ... Liquid crystal cell, 12 ... Linearly polarizing plate, 20 ... Surface light source device, 22 ... LED light source, 30 ... Light guide plate, 31 ... Front surface, 32 ... Back surface, 33 , 34 ... side face, 35 ... processed dot, 41 ... various films, 42 ... reflective sheet, 50 ... laser irradiation device, 51 ... laser irradiation head, 52 ... laser irradiation section, 54 ... laser, 55 ... dot pattern processing section, 60 ... original plate (translucent resin sheet), 60a ... processed surface, 60b ... non-processed surface, 70 ... conveying means, 71 ... conveying belt, 71a ... opening, 72 ... conveying roller, 73 ... suction box, 73a ... top plate 73b ... opening, 200 ... light guide plate manufacturing device (optical sheet manufacturing device), D ... gap distance, L ... length of diagonal of original plate, T ... length of diagonal of original plate, A ... moving direction of original plate, B ... Hara Width direction of.

Claims (9)

A dot pattern that forms a dot pattern by irradiating a laser on the back surface of an original plate in an optical sheet in which an incident surface for incident light emitted from a light source is formed on a side surface and an outgoing surface for the incident light is formed on the surface. A method for manufacturing a processed optical sheet,
An optical sheet manufacturing method, wherein when performing the dot pattern processing, the non-processed surface of the original plate is sucked and adsorbed to eliminate warpage and lateral deviation.   The method for producing an optical sheet according to claim 1, wherein the original plate has a thickness of 4.5 mm or less.   The method for producing an optical sheet according to claim 1 or 2, wherein a length L of a diagonal line of the original plate is 500 mm or more. The length L and thickness T of the diagonal of the said original plate satisfy | fill following formula (1), The manufacturing method of the optical sheet as described in any one of Claims 1-3 characterized by the above-mentioned.

However, L is the length (mm) of the diagonal of the original plate, and T is the thickness (mm) of the original plate.   The method for producing an optical sheet according to claim 1, wherein a dot density of a dot pattern applied to the original plate is 150 dpi or more.   The optical sheet manufactured by the manufacturing method of the optical sheet as described in any one of Claims 1-5. The optical sheet according to claim 6,
A surface light source device comprising: a light source disposed opposite to an incident surface of the optical sheet. The surface light source device according to claim 7,
A transmission-type image display device including a transmission-type image display unit that is disposed to face an emission surface of the optical sheet and displays an image by being irradiated with light emitted from the light source. An incident surface for incident light emitted from the light source is formed on the side surface, an incident surface for incident light is formed on the surface, and dot pattern processing is performed to form a dot pattern by irradiating a laser on the rear surface. An optical sheet manufacturing apparatus for manufacturing an optical sheet,
An apparatus for producing an optical sheet, wherein when performing the dot pattern processing, the processed surface of the original plate is sucked and adsorbed to eliminate warpage and lateral deviation.

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