JP2018101524A - Manufacturing method of light guide plate, light guide place, surface light source device, display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a light guide plate in which the number of components is small and which can be manufactured easily, and to provide a light guide plate, a surface light source device, and a display device.SOLUTION: A manufacturing method of a light guide plate 12 which includes a body part 121 and a surface function layer 125 which is formed on an observer side surface 12d side of the body part 121, whose refractive index is lower than that of the body part 121, and which has a fine irregular shape 126 on a surface includes: a resin extrusion step of co-extruding a thermoplastic resin composition R1 for forming the body part 121 and a thermoplastic resin composition R2 for forming the surface function layer 125 in a belt-like manner between a shaped sheet 70 having an irregular shape part 73 for shaping the body part 121, and a second roll 82 for shaping the irregular shape 126 of the surface function layer 125; a shaping step of pressing the extruded thermoplastic resin compositions R1, R2 to the shaped sheet 70 and the second roll 82 while conveying them, and shaping the body part 121 and the irregular shape 126 of the surface function layer 125; and a curing step of curing the thermoplastic resin compositions R1, R2 while conveying them.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for manufacturing a light guide plate, a light guide plate, a surface light source device, and a display device.

2. Description of the Related Art Conventionally, a display device that displays an image by illuminating a display unit such as an LCD (Liquid Crystal Display) panel with a surface light source device is known.
Surface light source devices are broadly classified into a direct type in which a light source is arranged directly under an optical member such as various optical sheets and an edge light type in which a light source is arranged on a side surface side of the optical member. Among these, the edge light type surface light source device has the advantage that the surface light source device can be made thinner than the direct type because the light source is disposed on the side surface side of the optical member such as a light guide plate. Widely used.
In addition, the edge light type surface light source device is widely used not only as a backlight of a display device but also as a front light in recent years.

Generally, in an edge light type surface light source device, a light source is disposed at a position facing a light incident surface that is a side surface of a light guide plate, and light emitted from the light source enters the light guide plate from the light incident surface, While repeating reflection on the light exit surface and the surface facing the light exit surface, the light travels in the direction (light guide direction) orthogonal to the light entrance surface toward the face facing the light entrance surface.
Then, by changing the traveling direction of the light according to the uneven shape provided on the light guide plate, light is gradually emitted from each position on the light exit surface along the light guide direction to the LCD panel side (for example, patents) Reference 1).

JP 2009-217283 A

In a display device that uses an edge light type surface light source device as a front light, the image displayed on the display unit is visually recognized through the light guide plate, so that reflection of external light such as sunlight and illumination light or glare is prevented. In addition, an antiglare layer having a fine uneven shape on the viewer side of the light guide plate is known.
However, in general, this anti-glare layer is formed by attaching an anti-glare film or the like, which is a separate member to the light guide plate, to the light guide plate via a bonding layer, etc., and increasing the number of parts of the light guide plate There were problems such as an increase in production man-hours and an increase in production costs.

  An object of the present invention is to provide a light guide plate manufacturing method, a light guide plate, a surface light source device, and a display device that have a small number of components and are easy to manufacture.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
The invention of claim 1 includes a light incident surface (12a) on which light is incident, a light exit surface (12c) that intersects the light incident surface and emits light, and a facing surface (12b) that faces the light incident surface. A light guide plate having a surface (12d) opposed to the light exit surface, and guiding the light incident from the light entrance surface toward the facing surface while emitting the light from the light exit surface. A main body part (121) for guiding incident light to the facing surface side and a surface side surface of the main body part facing the light output surface, the refractive index being lower than that of the main body part, and the main body part And a surface functional layer (125) having a concavo-convex shape (126) on the surface opposite to the side, wherein the first shaped portion (73) corresponding to the shape of the main body portion is provided. And a second shaping portion corresponding to the uneven shape of the surface functional layer. A resin extrusion step of co-extruding the first resin (R1) forming the main body portion and the second resin (R2) forming the surface functional layer in a band between the second molding plate (82); The first and second resins extruded by the resin extrusion step are pressed against the first molding plate and the second molding plate while transporting the first resin and the second resin, and the concave and convex shapes of the main body portion and the surface functional layer are formed. It is a manufacturing method of a light-guide plate provided with the shaping process to shape, and the hardening process hardened while conveying said 1st resin and said 2nd resin.
Invention of Claim 2 is a manufacturing method of the light-guide plate of Claim 1, Said 1st shaping | molding plate (70) is a strip | belt-shaped shaping sheet, In said resin extrusion process, said 1st shaping | molding plate is The light guide plate manufacturing method is characterized in that the first resin (R1) that has been transported in the longitudinal direction and is extruded in a band shape is brought into contact with the surface of the shaped sheet.
A third aspect of the present invention is the light guide plate manufacturing method according to the second aspect, wherein after the curing step, the first resin (R1) cured from the first molding plate (70) is released. It is a manufacturing method of the light-guide plate characterized by providing a process.
Invention of Claim 4 is a manufacturing method of the light-guide plate of any one of Claim 1- Claim 3, WHEREIN: The said 2nd shaping | molding plate (82) is roll shape, The said surrounding side is the said A second shaped part is formed, and in the resin extrusion step, the second resin (R2) before curing flowing in a strip shape is brought into contact with a peripheral side surface of the second molding plate. It is a manufacturing method.
The invention of claim 5 includes a light incident surface (12a) on which light is incident, a light exit surface (12c) that intersects the light incident surface and emits light, and a facing surface (12b) that faces the light incident surface. A light guide plate that has a surface (12d) facing the light exit surface, and guides the light incident from the light entrance surface to the facing surface side and emits the light from the light exit surface, the light entrance surface Formed on the surface of the main body that faces the light exit surface of the main body, and has a refractive index lower than that of the main body. A surface functional layer (125) having a concavo-convex shape on the surface opposite to the portion side and having a pencil hardness (JIS K 5600-5-4) of 2H or more, the main body portion and the surface functional layer And at least a part of the light incident from the light incident surface is totally reflected at the interface (K). A light guide plate to (12).
A sixth aspect of the present invention is the light guide plate according to the fifth aspect, wherein the refractive index difference at the interface (K) between the surface functional layer (125) and the main body (121) is 0.05 to 0.20. It is a light guide plate (12) characterized by being.
The invention according to claim 7 is the light guide plate according to claim 5 or 6, wherein the light exit surface (12c) is at least from the light incident surface (12a) side toward the opposing surface (12b) side. The light guide plate (12) is characterized in that an uneven portion (122) in which a plurality of convex unit optical shapes (123) are arranged is formed.
The invention of claim 8 is the light guide plate according to any one of claims 5 to 7, wherein the surface functional layer (125) includes at least an antiglare function, a hard coat function, an antifouling function, A light guide plate (12) characterized by having at least one function of an antistatic function.
The invention of claim 9 is provided at a position facing the light guide plate (12) according to any one of claims 5 to 8 and the light incident surface (12c) of the light guide plate. A surface light source device (10) comprising: a light source unit (11) that projects light onto a writing light surface.
The invention of claim 10 is a display device (1) comprising: the surface light source device (10) according to claim 9; and a display unit (13) disposed at a position facing the light exit surface of the light guide plate. It is.

  According to the present invention, it is possible to provide a light guide plate manufacturing method, a light guide plate, a surface light source device, and a display device that are easy to manufacture with a small number of components.

It is a figure explaining the display apparatus 1 of embodiment. It is a figure explaining the light-guide plate 12 of embodiment. It is the figure which expanded a part of cross section parallel to the main light guide direction (X direction) and thickness direction (Z direction) of the light of the display apparatus 1 of embodiment. It is a figure explaining the shaping sheet 70 used for shaping | molding of the light-guide plate 12 of embodiment. It is a figure explaining the manufacturing method of the light-guide plate 12 of embodiment. It is a figure which shows the modification of the manufacturing method of the light-guide plate.

Embodiments of the present invention will be described below with reference to the drawings. In addition, each figure shown below including FIG. 1 is the figure shown typically, and the magnitude | size and shape of each part are exaggerated suitably for easy understanding.
In the present specification, numerical values such as dimensions and material names of each member to be described are examples of the embodiment, and are not limited thereto, and may be appropriately selected and used.
In this specification, terms that specify shape and geometric conditions, for example, terms such as parallel and orthogonal, are strictly meanings, have similar optical functions, and can be regarded as parallel and orthogonal It also includes a state having an error of.

In this specification, words such as plate, sheet, and film are used, but these are generally used in the order of thickness in the order of plate, sheet, and film. This is also used in the specification. However, there is no technical meaning in such proper use, so these terms can be replaced as appropriate.
In the present specification, the sheet surface refers to a surface that is a planar direction of the sheet when viewed as the entire sheet. The same applies to the plate surface and the film surface.

(Embodiment)
FIG. 1 is a diagram illustrating a display device 1 according to the present embodiment.
FIG. 2 is a diagram illustrating the light guide plate 12 of the present embodiment. 2A is a plan view of the light guide plate 12 viewed from the light exit surface 12c side, and FIG. 2B is parallel to the main light guide direction (X direction) and the thickness direction (Z direction) of light. FIG. 5 is an enlarged view of a part of a cross section of the light guide plate 12.
FIG. 3 is an enlarged view of a part of a cross section parallel to the main light guide direction (X direction) and the thickness direction (Z direction) of the display device 1 of the present embodiment.
The display device 1 of this embodiment includes a surface light source device 10 and an LCD panel 13. In the display device 1, the surface light source device 10 is disposed on the viewer side of the LCD panel 13, and the LCD panel 13 is illuminated from the viewer side by the surface light source device 10 to display video information formed on the LCD panel 13. To do. That is, in the display device 1 of the present embodiment, the observer E visually recognizes the video information displayed on the display surface 13 a of the LCD panel 13 through the light guide plate 12.
Further, in the display device 1 of the present embodiment, a light guide plate 12 and an LCD panel 13 of a surface light source device 10 to be described later are integrally bonded via a bonding layer 14.

2 and 3 and the following description including FIG. 1, in order to facilitate understanding, in the usage state of the display device 1, two directions that are parallel to the screen of the display device 1 and are orthogonal to each other. Among these, a direction orthogonal to a light incident surface 12a (to be described later) of the light guide plate 12 is defined as an X direction, and a direction orthogonal to the X direction is defined as a Y direction. Further, a direction (thickness direction) orthogonal to the screen of the display device 1 is defined as a Z direction. In the thickness direction (Z direction), the + Z side is the observer side, and the −Z side is the back side.
The screen of the display device 1 of this embodiment corresponds to the surface (hereinafter referred to as the display surface) 10a on the most + Z side (observer side) of the surface light source device 10, and the “front direction” of the display device 1 is this It is the normal direction of the display surface 10a, is parallel to the Z direction, and coincides with the normal direction of the plate surface of the light guide plate 12 described later.

The LCD panel 13 is a reflective display unit that is formed of a liquid crystal display element and forms video information on the display surface 13 a of the LCD panel 13.
The LCD panel 13 has a substantially flat plate shape, and its outer shape is rectangular when viewed from the Z direction.

  The surface light source device 10 is a device that illuminates the LCD panel 13 from the observer side (+ Z side), and includes a light source unit 11, a light guide plate 12, and the like. The surface light source device 10 is an edge light type surface light source device (front light).

The light source unit 11 is a part that emits light that illuminates the LCD panel 13. The light source unit 11 is disposed along the Y direction at a position facing a light incident surface 12a (described later) which is one end surface (+ X side) of the light guide plate 12 in the X direction (+ X side).
The light source unit 11 is formed by arranging a plurality of point light sources at predetermined intervals in the Y direction. As this point light source, an LED (Light Emitting Diode) light source is used. The light source unit 11 may be, for example, a line light source such as a cold cathode tube, or may have a form in which a light source is disposed on an end surface of a light guide extending in the Y direction.
Further, from the viewpoint of improving the utilization efficiency of light emitted from the light source unit 11, a reflector (not shown) may be provided so as to cover the outside of the light source unit 11.

The light guide plate 12 is rectangular when viewed from the front direction (Z direction), and has two opposing sides parallel to the X direction and two opposite sides parallel to the Y direction.
The light guide plate 12 is a substantially flat plate member that guides light, and includes a light incident surface 12a, a facing surface 12b, a light exit surface 12c, and an observer side surface 12d.

The light incident surface 12 a and the opposing surface 12 b are located at both ends of the light guide plate 12 in the X direction (−X side end, + X side end) and are opposed to each other, and are normal to the plate surface of the light guide plate 12. It extends in parallel to the Y direction when viewed from the direction (Z direction). The light exit surface 12c and the observer side surface 12d are located at both ends of the light guide plate 12 in the Z direction (−Z side end, + Z side end) and face each other.
The plate surface of the light guide plate 12 is parallel to the XY plane, and the observer side surface 12d that becomes the display surface 10a of the display device 1 is a surface parallel to the plate surface.
The light guide plate 12 of the present embodiment is formed in a rectangular shape as viewed from the thickness direction (Z direction), and from the viewpoint of guiding more light, among the four side surfaces parallel to the thickness direction, Surfaces parallel to the longitudinal direction (Y direction) are defined as a light incident surface 12a and a facing surface 12b. However, the present invention is not limited to this, and the light incident surface 12a and the facing surface 12b may be surfaces parallel to the lateral direction (X direction).

As shown in FIG. 2B, the light guide plate 12 of the present embodiment has a main body 121 and a surface functional layer located on the viewer side (+ Z side) of the main body 121 in the thickness direction (Z direction). 125.
The light exit surface 12 c of the light guide plate 12 corresponds to the back side (−Z side) surface of the main body 121, and the viewer side surface 12 d corresponds to the viewer side (+ Z side) surface of the surface functional layer 125.

The surface functional layer 125 has optical transparency, and the surface on the observer side is rough due to the fine uneven shape 126. In the present embodiment, the size and arrangement of the convex shape and the concave shape forming the concavo-convex shape 126 are fine and irregular. In addition, not only this but the convex shape and concave shape which form the uneven | corrugated shape 126 may have regularity in the magnitude | size and arrangement | sequence.
Further, the refractive index of the surface functional layer 125 is smaller than the refractive index of the main body 121. The interface K between the surface functional layer 125 and the main body 121 is parallel or substantially parallel to the plate surface and the XY plane of the light guide plate 12.

The surface functional layer 125 of the present embodiment has an antiglare function that prevents unnecessary external light such as sunlight and illumination light from being reflected or glare due to the above-described uneven shape.
Further, the surface functional layer 125 of the present embodiment has a hard coat function in which the pencil hardness (JIS K 5600-5-4) is 2H or more, and the display surface 10a of the display device 1 (observer side surface of the light guide plate 12). 12d) has a function of reducing scratches and the like.
The surface functional layer 125 is not limited to the above example, and may have an antistatic function, an antifouling function, an antireflection function, or the like in accordance with desired performance. The surface functional layer 125 has a thickness of about 10 to 200 μm.
The surface functional layer 125 of the present embodiment is formed of an acrylic thermoplastic resin or the like.

The main body 121 is a main part that has light transparency and guides light incident from the light incident surface 12a.
The main body 121 has an interface K with the surface functional layer 125 on the observer side (+ Z side), and a light exit surface 12c on the back side (−Z side). The main body 121 is made of a material having a higher refractive index than the surface functional layer 125.
The refractive index difference between the main body 121 and the surface functional layer 125 is preferably 0.05 or more and 0.20 or less from the viewpoint of efficiently guiding light. It is not necessary to consider the selection of materials and the ease of acquisition, and when only the light guiding efficiency is considered, the difference in refractive index between the main body 121 and the surface functional layer 125 is 0. It is desirable to set it to 05 or more.

  As shown in FIG. 2, the light exit surface 12c has convex columnar unit optical shapes 123 arranged at predetermined intervals in a direction perpendicular to the light entrance surface 12a (light guide direction, X direction). The formed uneven part 122 is formed. Thereby, the light guided into the light guide plate 12 can be appropriately emitted from the light exit surface 12c.

As shown in FIG. 2, the concavo-convex portion 122 extends in the Y direction of the light guide plate 12, and has a rectangular cross section convex portion 123 arranged in the X direction at a predetermined interval, and a rectangular cross section positioned between the convex portions 123. And a recess 124.
The concavo-convex shape of the concavo-convex portion 122 is finely formed. For example, the dimension of the side surface 123b of the convex portion 123, that is, the depth d (dimension in the Z direction) from the top surface 123a to the bottom surface 124a of the concave portion 124 is It is about 0.1 μm or more and 3.0 μm or less. Further, the width W2 (dimension in the X direction) of the bottom surface 124a of the recess 124 and the width W1 (dimension in the X direction) of the top surface 123a of the projection 123 are about 1 μm or more and 30 μm or less.

The width W2 of the bottom surface 124a of the concave portion 124 and the width W1 of the top surface 123a of the convex portion 123 may be the same or different. In addition, the width W2 of the bottom surface 124a of the concave portion 124 and the width W1 of the top surface 123a of the convex portion 123 may be constant or may vary along the arrangement direction (X direction) of the convex portions 123.
Moreover, the shape of the uneven | corrugated | grooved part 122 is not restricted to the above-mentioned example, Another form may be applied and a several aspect may be used in combination.
As other forms of the concavo-convex part 122, for example, a form having a predetermined cross section and extending so as to be inclined with respect to the width direction (Y direction) of the light guide plate 12, and a plurality of conical convex parts are seen in a plan view. And a form having a two-dimensional shape arranged vertically and horizontally, a form in which a plurality of convex portions are arranged in a dot shape in plan view, and the like.

The main body 121 has a thickness of about 300 to 600 μm.
The main body 121 is made of a light-transmitting thermoplastic resin. Examples of the material for forming the main body 121 include a polymer resin having an alicyclic structure, a methacrylic resin, a polycarbonate resin, a polystyrene resin, an acrylonitrile-styrene copolymer resin, a methyl methacrylate-styrene copolymer resin, an ABS resin, Examples thereof include thermoplastic resins such as polyethersulfone resins. These are widely used as materials for optical members such as a light guide plate, and have excellent mechanical characteristics, optical characteristics, stability, workability, and the like, and are available at low cost.

As shown in FIG. 3, the light guide plate 12 has a light output surface 12 c bonded to the LCD panel 13 via a bonding layer 14.
The bonding layer 14 has optical transparency and is formed of an adhesive or the like having a refractive index lower than that of the main body 121 of the light guide plate 12. The bonding layer 14 of this embodiment is formed of an acrylic adhesive, but is not limited thereto, and may be formed of a silicon adhesive or the like. In addition, as such a bonding layer 14, as long as it has a sufficient transmittance, is colorless and transparent, has a small influence on image light, and has a refractive index lower than that of the main body 121 of the light guide plate 12, An adhesive may be used.

As shown in FIG. 3, the bonding layer 14 is formed so as to fill the uneven shape of the uneven portion 122 of the light output surface 12 c of the light guide plate 12.
The difference in refractive index between the bonding layer 14 and the main body 121 is set to be 0.05 or more and 0.20 or less in view of efficiently guiding light, selection of materials, ease of acquisition, and the like. preferable. Note that it is not necessary to consider the selection of materials and the ease of acquisition, and in the case of considering only the light guide efficiency, the refractive index difference between the bonding layer 14 and the main body 121 is 0.05 or more. Is desirable.

Next, how the light is guided by the light guide plate 12 of this embodiment will be described.
The light guide plate 12 of the present embodiment causes light emitted from the light source unit 11 to enter the light guide plate 12 (main body unit 121) from the light incident surface 12a. Then, as shown in FIG. 3, the light L1 and L2 traveling in the main body 121 are opposed to the light incident surface 12a while being totally reflected by the light exit surface 12c (top surface 123a and bottom surface 124a) and the interface K. The light is guided mainly in the X direction to the surface 12b side (+ X side). At this time, a part L2 of the light incident on the light exit surface 12c is appropriately emitted from the light exit surface 12c to the LCD panel 13 side (−Z side), for example, by entering the side surface 123b of the convex portion 123 at a critical angle or less.
The light emitted to the LCD panel 13 side passes through the bonding layer 14 and enters the LCD panel 13. The LCD panel 13 is a reflective display unit, and displays video information on the display surface 13a of the LCD panel 13 so as to be visible to an observer E by reflecting incident light.

(About the manufacturing method of the light-guide plate 12)
FIG. 4 is a view for explaining a shaping sheet 70 used for forming the light guide plate 12 of the present embodiment.
As shown in FIG. 4, the shaping sheet 70 is a molding plate formed of a long (band-shaped) flexible resin in which a base portion 71 and a molding layer 72 are laminated. Before being manufactured, it is in a wound state.
The base material portion 71 is a base material that is the basis of the shaped sheet 70, and is formed of, for example, a resin such as polyethylene terephthalate, polypropylene, or polycarbonate.

The molding layer 72 is a layer in which a concavo-convex shape portion 73 that corresponds to the concavo-convex portion 122 of the light exit surface 12c of the light guide plate 12 and is shaped is formed on the surface (surface) opposite to the base portion 71 side. It is. The molding layer 72 is made of, for example, a resin such as urethane acrylate or epoxy acrylate.
The concave and convex portion 73 provided on the molding layer 72 is arranged in a plurality on the surface of the molding layer 72 in order to simultaneously mold a plurality of main body portions 121 of the light guide plate 12.
In the present embodiment, as an example, an example in which the concavo-convex shape portions 73 are formed in three rows in a direction parallel to the short side of the long shaped sheet 70 and in a plurality of stages in a direction parallel to the long side. I will give a description. In addition, the number of the concavo-convex shape portions 73 arranged in the direction parallel to the short side is not limited thereto, and may be appropriately changed according to a desired size of the light guide plate 12 or the like.

FIG. 5 is a diagram illustrating a method for manufacturing the light guide plate 12 of the present embodiment. FIG. 5 shows a manufacturing apparatus 80 for manufacturing the light guide plate 12 of the present embodiment.
As shown in FIG. 5, the manufacturing apparatus 80 for manufacturing the light guide plate 12 includes a shaping sheet 70, a first roll 81, a second roll 82, a third roll 83, a fourth roll 84, a peeling roll 85, a die 86, A first extruder 87, a second extruder 88, nip rolls 89 and 90, a cutting unit (not shown), and the like are provided.

The first extruder 87 heats, melts, and supplies the thermoplastic resin composition R1 (resin that forms the main body 121) to the die 86.
The second extruder 88 heats and melts the thermoplastic resin composition R <b> 2 (resin that forms the surface functional layer 125) and supplies it to the die 86.
The die 86 is an opening through which the thermoplastic resin compositions R1 and R2 supplied from the first extruder 87 and the second extruder 88 are discharged, and the molten thermoplastic resin compositions R1 and R2 are discharged into a predetermined area. Extrude in the form of a two-layer laminate, spreading in a strip to the width.

The 1st roll 81, the 2nd roll 82, the 3rd roll 83, and the 4th roll 84 are substantially cylindrical shapes, and can be rotationally driven by making the central axis into a rotating shaft.
The 2nd roll 82 is a forming roll by which the uneven | corrugated shape used as the shaping | molding die for shaping the uneven | corrugated shape 126 of the surface functional layer 125 was formed in the surface.
Each of the first roll 81, the second roll 82, the third roll 83, and the fourth roll 84 is a cooling roll provided with a temperature adjusting unit (not shown) so that the temperature at the roll core becomes a predetermined temperature. The temperature is adjusted. Moreover, the 1st roll 81, the 2nd roll 82, the 3rd roll 83, and the 4th roll 84 convey and cool the thermoplastic resin composition R1, R2 and the shaping sheet 70 around them.

As shown in FIG. 5, the shaped sheet 70 wound up is unwound, and a first roll 81 and a second roll 82 arranged with a predetermined gap with respect to the first roll 81. Transport sequentially. Here, the conveying direction S of the shaped sheet 70 is a direction parallel to a direction perpendicular to the short side of the shaped sheet 70.
Then, a melted thermoplastic resin composition R1 (main body 121 is formed between the second roll 82 and the surface 70a (the surface of the molding layer 72) on the side where the concave and convex portion 73 of the shaped sheet 70 is formed. Resin) and the thermoplastic resin composition R2 (resin that forms the surface functional layer 125) are co-extruded from the die 86 (resin extrusion step). At this time, the thermoplastic resin composition R1 is extruded so as to be on the first roll 81 and the shaping sheet 70 side, and the thermoplastic resin composition R2 is on the second roll 82 side.

Next, the extruded thermoplastic resin compositions R1 and R2 are sandwiched and pressed between the first roll 81 and the second roll 82 while being conveyed together with the shaped sheet 70.
Thereby, the thermoplastic resin composition R1 is filled in the concave and convex portion 73 provided on the surface of the molding layer 72 (see FIG. 4) of the shaping sheet 70, and the second roll 82 and the atmosphere (outside air, manufacturing apparatus) The surface of the shaped sheet 70 is hardened by being cooled in the working environment or the like, and the shape of the shaped sheet 70 along the uneven portion 73 is shaped. On the other hand, the thermoplastic resin composition R2 is sufficiently filled into the uneven shape formed on the outer peripheral surface of the second roll 82, and the uneven shape 126 is formed (shaping step).

Next, the thermoplastic resin compositions R1 and R2 are further cooled and cured through the third roll 83 and the fourth roll 84, and finally the shape is fixed in a state of being integrally laminated (curing step). . Thereby, it is possible to obtain a main body multi-sided sheet F1 in which the surface functional layer 125 in which the concavo-convex shape 126 is formed is integrally laminated on the layer in which the main body part 121 of the light guide plate 12 is multi-sided vertically and horizontally.
Next, the main body multi-faced sheet F <b> 1 is released from the shaped sheet 70 by the peeling roll 85.

About the method of providing the joining layer 14 in the surface (light-emitting surface 12c) which has the uneven | corrugated | grooved part 122 of the light-guide plate 12, you may employ | adopt suitably.
For example, as shown in FIG. 5, the pressure-sensitive adhesive sheet N in which the bonding layer 14 formed of the pressure-sensitive adhesive is formed on one side of the peelable base material 15 is unwound, and the body portion 121 of the body portion multi-faced sheet F1 is unwound. The bonding layer 14 is formed by supplying the surface on which the light exit surface 121c is formed so that the bonding layer 14 faces, pressing the main body multi-sided sheet F1 and the adhesive sheet N with the nip rolls 89 and 90, and bonding them together. May be.

Thereby, it is possible to obtain the main body portion multi-faced sheet F2 in which the bonding layer 14, the main body portion 121, and the surface functional layer 125 in which the base material 15 having peelability is laminated on one side, By performing processing such as punching and cutting, a plurality of separated light guide plates 12 can be obtained. In the assembly process of the display device 1, the base material 15 is peeled off, and the light guide plate 12 can be easily bonded to the LCD panel 13 by the bonding layer 14.
Further, the present invention is not limited to the above example, and for example, a plurality of light guide plate main body parts 121 are created by punching or cutting the main body part multi-faced sheet F2, and the uneven parts of the main body part 121 are formed. The bonding layer 14 may be provided by applying an adhesive to the surface having 122.

Conventionally, the light guide plate 12 having the surface functional layer 125 is generally manufactured by forming the main body 121 and then laminating an antiglare film integrally with an adhesive layer or the like.
However, according to the present embodiment, the light guide plate 12 having an antiglare function and capable of guiding light well can be easily manufactured with a small number of parts, and reduction in production man-hours and production costs can be suppressed.
Moreover, according to this embodiment, it is also possible to perform on one manufacturing line from formation of the main-body part 121 of the light-guide plate 12, formation of the joining layer 14, and the cutting process to each light-guide plate 12 on a production cost. Reduction, reduction of conveyance (horizontal holding) of each member in the manufacturing process, and the like can be realized.

  It should be noted that a punching process or the like is performed on the main body multi-sided sheet F1 in which the main body part 121 is multi-faced and the surface functional layer 125 are integrally laminated, and the plurality of light guide plates 12 separated into individual pieces are obtained. The bonding layer 14 and the like may be individually bonded or formed.

(Deformation)
Without being limited to the embodiments described above, various modifications and changes are possible, and these are also within the scope of the present invention.
(1) In the embodiment, the example in which the light guide plate 12 is formed by the rolled shaped sheet 70 is shown, but the embodiment is not limited thereto. For example, it is good also as a form shape | molded using the roll plate by which the uneven | corrugated shaped part 73 was formed in the column-shaped peripheral side instead of the shaping sheet 70. FIG. That is, the first roll 81 may have a substantially cylindrical shape, and a roll plate in which the concave and convex portion 73 is formed on the peripheral side surface may be used.

(2) In the embodiment, the example in which the surface functional layer 125 is formed by coextrusion molding with the layer on which the main body part 121 is multifaceted is shown. However, the present invention is not limited to this. The surface functional layer 125 formed into a long shape (band shape) is conveyed between the first roll and the second roll, and the thermoplastic resin composition R1 is transferred from the die to the shaping sheet 70 and the surface function. A mode of discharging between the layers 125 may be employed.
FIG. 6 is a view showing a modification of the method for manufacturing the light guide plate 12. FIG. 6 shows a modified manufacturing apparatus 180.
As shown in FIG. 6, the manufacturing apparatus 180 of this modified form includes a first roll 181, a second roll 182, a third roll 183, a fourth roll 184, a peeling roll 185, a die 186, an extruder 187, and a shaping sheet. 70 etc.

The first roll 181, the second roll 182, the third roll 183, and the fourth roll 184 have a substantially cylindrical shape, and can be driven to rotate with the central axis as a rotation axis. As for this 1st roll 181, the 2nd roll 182, the 3rd roll 183, and the 4th roll 184, the peripheral side surface is substantially smooth surface shape.
Also, the first roll 181, the second roll 182, the third roll 183, and the fourth roll 184 are all cooling rolls provided with a temperature adjusting unit (not shown), and the temperature at the roll core is a predetermined temperature. The temperature is adjusted to be.

As shown in FIG. 6, the wound shaped sheet 70 is unwound, and the first roll 181 and the second roll 182 arranged with a predetermined gap with respect to the first roll 181 It is transported at a predetermined speed in between.
In addition, the wound long surface functional layer 125 is formed at a predetermined speed between the first roll 181 and the second roll 182 with the surface on which the uneven shape 126 is formed as the second roll 182 side. Transport.
Next, it is melted by an extruder 187 between the surface 70a of the shaped sheet 70 on which the concave and convex portion 73 is formed and the surface 125a of the long surface functional layer 125 on which the concave and convex shape 126 is not formed. The thermoplastic resin composition R1 (resin forming the main body 121) thus formed is spread out from the die 186 to a predetermined width and extruded.

Next, the extruded thermoplastic resin composition R1 is sandwiched and pressed between the first roll 181 and the second roll 182 while being conveyed together with the shaping sheet 70 and the elongated surface functional layer 125.
Thereby, the thermoplastic resin composition R1 is filled in the concavo-convex shape portion 73 provided on the surface of the molding layer 72 of the shaping sheet 70, and the second roll 182 and the atmosphere (outside air, working environment of the manufacturing apparatus, etc.). At least the surface thereof is hardened by being cooled at, and a shape along the uneven portion 73 of the shaped sheet 70 is formed. Moreover, the surface functional layer 125 is laminated | stacked integrally on the surface on the opposite side to the shaping sheet 70 side of thermoplastic resin composition R1.

Next, the thermoplastic resin composition R1 is further cooled through the third roll 183 and the fourth roll 184, and finally the shape is fixed in a state where the surface functional layer 125 is laminated integrally. Thereby, the main body part multi-sided sheet F11 in which the main body part 121 of the light guide plate 12 is multi-faced vertically and horizontally and the surface functional layer 125 are integrally laminated can be obtained.
Next, the main body multi-sided sheet F <b> 11 is released from the shaped sheet 70 by the peeling roll 185. Thereafter, similarly to the above-described embodiment, the light guide plate 12 with the base material 15 and the bonding layer 14 is obtained by bonding the adhesive sheet N including the base material 15 and the bonding layer 14 and appropriately cutting the adhesive sheet N.
Even with such a manufacturing method, the light guide plate 12 with a small number of parts can be easily manufactured.

(3) In the embodiment, a layer for reducing reflection of light incident on the light guide plate 12 from the viewer side is provided on the viewer side surface 12d of the light guide plate 12 (observer side surface of the surface functional layer 125). The functional layer 125 may have an AGLR (anti-glare, low-reflection) function. By setting it as such a form, reflection of sunlight, illumination light, etc. can be reduced further, the fall of the contrast of the image displayed can be suppressed and visibility can be improved.

(4) In the embodiment, the display device 1 has shown the example in which the LCD panel 13 is disposed so as to face the light exit surface 12c of the light guide plate 12. However, the present invention is not limited to this, and various types of reflection types such as electronic paper are used. A display device may be arranged.

  In addition, although this embodiment and modification can also be used in combination as appropriate, detailed description is abbreviate | omitted. Further, the present invention is not limited by the above-described embodiments and the like.

DESCRIPTION OF SYMBOLS 1 Display apparatus 10 Surface light source device 11 Light source part 12 Light guide plate 121 Main body part 122 Concavity and convexity part 123 Convex part 124 Concave part 125 Surface functional layer 126 Concavity and convexity 13 LCD panel 14 Bonding layer

Claims (10)

A light incident surface on which light is incident; a light exit surface that intersects the light incident surface and emits light; a facing surface that faces the light incident surface; and a surface that faces the light exit surface; A light guide plate that emits light from the light exit surface while guiding light incident from the surface to the opposite surface side,
A main body for guiding light incident from the light incident surface to the opposite surface side;
A surface functional layer formed on the surface of the main body portion facing the light exit surface, having a refractive index lower than that of the main body portion, and having a concavo-convex shape on the surface opposite to the main body portion side,
A light guide plate manufacturing method comprising:
Between the first molding plate having a first shaping portion corresponding to the shape of the main body portion and the second molding plate having a second shaping portion corresponding to the uneven shape of the surface functional layer, the main body A resin extrusion step of co-extruding the first resin forming the part and the second resin forming the surface functional layer in a strip shape;
While conveying the first resin and the second resin extruded in the resin extrusion step, the first molding plate and the second molding plate are pressed against each other, and the concave and convex shapes of the main body portion and the surface functional layer are applied. Shaping process to form,
A curing step of curing while conveying the first resin and the second resin;
A method of manufacturing a light guide plate comprising: In the manufacturing method of the light-guide plate of Claim 1,
The first molding plate is a belt-shaped shaping sheet,
In the resin extrusion step, the first molding plate is conveyed in the longitudinal direction, and the first resin before curing extruded in a band shape is brought into contact with the surface of the shaped sheet;
A method of manufacturing a light guide plate characterized by the above. In the manufacturing method of the light-guide plate of Claim 2,
After the curing step, including a mold release step of releasing the first resin cured from the first molding plate;
A method of manufacturing a light guide plate characterized by the above. In the manufacturing method of the light-guide plate of any one of Claim 1- Claim 3,
The second molding plate has a roll shape, and the second shaping portion is formed on the peripheral side surface thereof.
In the resin extrusion step, the second resin before curing flowing in a band shape is brought into contact with the peripheral side surface of the second molding plate;
A method of manufacturing a light guide plate characterized by the above. A light incident surface on which light is incident; a light exit surface that intersects the light incident surface and emits light; a facing surface that faces the light incident surface; and a surface that faces the light exit surface; A light guide plate for emitting light from the light exit surface while guiding light incident from a surface to the opposite surface side,
A main body for guiding light incident from the light incident surface to the opposite surface side;
It is formed on the surface of the main body that faces the light exit surface, has a refractive index lower than that of the main body, has an uneven shape on the surface opposite to the main body, and has a pencil hardness (JIS K). 5600-5-4) is a surface functional layer of 2H or more,
With
Totally reflecting at least part of the light incident from the light incident surface at the interface between the main body and the surface functional layer;
A light guide plate characterized by The light guide plate according to claim 5,
The difference in refractive index at the interface between the surface functional layer and the main body is 0.05 to 0.20.
A light guide plate characterized by In the light guide plate according to claim 5 or 6,
The light exit surface is formed with a concavo-convex portion in which a plurality of convex unit optical shapes are arranged from at least the light incident surface side toward the facing surface side,
A light guide plate characterized by In the light-guide plate of any one of Claim 5 to Claim 7,
The surface functional layer has at least one of an antiglare function, a hard coat function, an antifouling function, and an antistatic function;
A light guide plate characterized by The light guide plate according to any one of claims 5 to 8,
A light source unit provided at a position facing the light incident surface of the light guide plate, and projecting light onto the light incident surface;
A surface light source device comprising: A surface light source device according to claim 9,
A display unit disposed at a position facing the light exit surface of the light guide plate;
A display device comprising:

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