JP3168190B2 - Light diffusing sheet, light guide, and method of using light guide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light diffusing sheet, a light guide sheet, and a method for using the same, which are suitable for applications such as lighting covers, lighting windows, building materials, road signs, signboards, liquid crystal display devices, and the like.

[0002]

2. Description of the Related Art As a light diffusing resin sheet, a transparent resin sheet whose surface is made uneven using a mold, and a light diffusing agent or a light scattering agent coated on the back surface of the transparent resin sheet are known. I have.

[0003] As a design sheet, there is known a transparent resin sheet on which the surface is subjected to density printing, shadow printing, or the like, or a sheet having an uneven shape formed inside the sheet.

Japanese Patent Publication No. 7-36742 discloses a glittering decorative sheet in which a transparent resin layer, a transparent embossed resin layer, and a light reflecting layer are sequentially laminated. However, this sheet has a light reflecting layer laminated on the uneven portion of the transparent embossed resin layer, and is not suitable for a light guide that uses light by entering light from the back or side surface of the sheet.

Japanese Patent Application Laid-Open No. Hei 3-256735 discloses that
Form a V-shaped groove on one surface of the polyvinyl chloride sheet,
A cut glass-like sheet having a V-groove formed side adhered to a polyvinyl chloride sheet having a smooth surface on the other surface, wherein a sealed air layer is formed in the V-groove. Has been disclosed. However, such a sheet having a structure in which an air layer is present therein is suitable for use as a light guide because the difference in the refractive index between the resin layer and the air layer is too large and the light diffusion property is too large. Absent.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin sheet that can be used as a light guide, a light diffusing sheet, and the like, and to provide a method of using the resin sheet as a light guide. Is to do.

[0007]

The above object of the present invention is achieved by the present invention having the following constitution. That is, the present invention has a laminated structure in which a transparent resin layer C is sandwiched between a transparent resin layer A and a transparent resin layer B, and is a resin sheet having a smooth outer surface. When the refractive index is different and the thickness direction of the sheet is y and the width direction is x, x
In a cross section indicated by the y-plane, at least one of a boundary surface between the resin layer A and the resin layer C and a boundary surface between the resin layer B and the resin layer C is a light diffusing sheet made of a resin sheet having an uneven shape or It is a light guide.

Further, the present invention is a resin sheet having a laminated structure of a transparent resin layer A and a transparent resin layer B, the resin sheet having a smooth outer surface, and the adjacent resin layers having different refractive indexes.
When the thickness direction of the sheet is y and the width direction is x, the boundary surface between the resin layer A and the resin layer B has an uneven shape in a cross section indicated by an xy plane, and the pitch p of the uneven shape is
It is a light diffusing sheet or a light guide made of a resin sheet of 2 to 5 mm .

Further, the present invention is a method of installing a light source on at least one end face (yz plane) of the light guide in the x direction and introducing light into the light guide.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a resin sheet manufacturing apparatus, a manufacturing method, and a resin sheet according to the present invention will be sequentially described. In the apparatus according to the first aspect of the present invention, the X direction coincides with the width direction of the resin sheet, the Y direction coincides with the thickness direction of the resin sheet, and the Z direction coincides with the traveling direction of the resin sheet. The Z direction can be taken in the vertical direction as shown in FIG. 4, or can be taken in the horizontal direction as shown in FIG.

The apparatus according to the first embodiment has a shape of two flow paths 41 and / or 42 for flowing resin a for resin layer A and resin b for resin layer B in composite flow forming section 22. And there is a great feature in the arrangement (FIG. 4). That is, the shapes of the flow paths 41 and / or 42 in the XZ cross section are such that the height R in the Z direction is small and the height R in the Z direction is small (or may be zero).
It is characterized by having a shape in which the portions Rm and / or Lm are alternately arranged (FIG. 6).

FIG. 1 shows a resin a for forming a resin layer A.
1 shows an apparatus in which the same resin is used as the resin b for forming the resin layer B. This resin is referred to as resin a (b). The resin a (b) is melt-extruded into the shaping head by the first extruder, passes through the first flow path 11 and the first metering pump 3
The resin c for forming the resin layer C is melt-extruded into the same shaping head by the second extruder 2 and reaches the second metering pump 4 through the second flow path 12. Resin a (b)
Are distributed to two flow paths 13 and 16 on the left and right sides by a distribution nozzle provided in the die pack 5, and the resin a
Then, a resin flow of the resin b is formed (FIG. 3). The resin c is guided to the flow channel 31 by the distribution nozzle via the flow channel 14 provided in the die pack 5 (FIG. 4).

When the resin a and the resin b are different resins, one of the resins is supplied by a third extruder (not shown).

The resin c is discharged from the slit-shaped flow path 31 into the composite flow forming section 22 to form a sheet-shaped flow having a predetermined thickness (FIG. 4). On the other hand, the resin a and the resin b form a composite resin flow by sandwiching the resin c discharged to the composite flow forming section 22 from both sides, and the composite resin is extruded from the composite outlet 23. After the composite resin is taken up by the cooling roll group 10 and shaped into a sheet,
The sheet material is cut into a predetermined length by the sheet cutting machine 15. (FIGS. 1 and 2) In the case of shaping into a thin film-like material, the film is wound on a winding machine via a cooling roll.

In the composite flow forming section 22, the flow path 41,
Due to the relative arrangement relationship between 42 and the flow path, the resin c
Under the action of the resin b, the cross-sectional shape in the XY cross-section is deformed to a desired shape.

Hereinafter, an apparatus of the present invention and a method for producing a resin sheet thereof will be described with reference to the drawings.

FIGS. 1 to 4 are views schematically showing an example of the apparatus according to the first embodiment of the present invention. FIGS. 1 and 2 are a schematic plan view and a side view of the entire apparatus, and FIGS. 4 is a plan sectional view and a longitudinal sectional view showing an example of the internal structure of the same device.

FIG. 5 is a perspective view taken along the line II-II of FIG.

FIGS. 6 and 7 show a resin flow path in a manufacturing apparatus according to a typical embodiment of the present invention. FIG. 6 is a sectional view taken along line III-III shown in FIG. 7
FIG. 7 is a sectional view taken along line IV-IV shown in FIG. 6.

In this apparatus, the flow path 31 has an outlet with a constant interval from one end of the composite flow forming section 22 in the X direction to the other end.

The portions Ln and Lm of the flow path 41 and the flow path 42
Are arranged symmetrically with respect to the XZ plane including the flow path 31. Parts Ln and Rn in X direction
Are equal, and the lengths of the portions Lm and Rm are also equal.
The heights of △ Ln and △ Rn in the Z direction are equal, and
The heights of Lm and ΔRm are also equal. These parts Ln, Lm
The widths and heights of the portions Rn and Rm can be appropriately changed in each device or in the same device.
The flow rate and flow rate of the resin a and the resin b are determined by the width and height of these flow paths.

FIG. 8 shows a cross-sectional shape of the resin layer at a position downstream of the composite resin flow path with respect to FIG. Channel 3
The resin c that has flowed out from 1 in a plate shape is deformed by the flow action of the resin a and the resin b indicated by arrows in FIG.
The cross-sectional shape of the resin layer C has a structure in which lens-shaped blocks are connected as shown in FIG. 8 and FIG. 30A. In FIG. 8, in order to facilitate understanding of the relationship between the shapes of the flow channels 41 and 42 and the cross-sectional shape of the finally manufactured resin sheet, the flow channel 41 located upstream of the position shown in FIG. , 42
Is written for convenience.

FIGS. 9 and 10 are views schematically showing another example of the device according to the first embodiment of the present invention, and FIG. 9 is a sectional view taken along line III-III in FIG. FIG.
This shows an apparatus in which parts Ln and Lm are formed in one flow path 41, and neither part Rn nor Rm is formed in the other flow path 42. The cross-sectional shape of the flow channel 41 is the same as that in FIG. FIG. 10 is a composite diagram displayed in the same manner as in FIG.

When this apparatus is used, FIGS.
As shown in FIG. 2B, a resin sheet having an uneven shape formed only on the interface between the resin layer A and the resin layer C is manufactured.

FIGS. 11 and 12 are views schematically showing another example of the apparatus according to the first embodiment of the present invention, and FIG. 11 is a sectional view taken along line III-III in FIG. In the apparatus of FIG. 11, the flow path 41
The portion Ln and the Rm of the flow path 42 are arranged symmetrically, and the Lm of the flow path 41 and the Rn of the flow path 42 are arranged symmetrically. Channel 4
The cross-sectional shapes of 1, 42 are the same as in FIG. FIG. 12 is a composite diagram displayed in the same manner as in FIG.

Using this device, FIG. 12 or FIG.
A resin sheet as shown in d is manufactured.

FIG. 13 shows the arrangement relationship of the portions Ln and the like of the flow paths 41 and 42 as in FIG. 6, and as shown in FIG. An apparatus having a structure in which a small amount of resin b can flow is shown. FIG. 13 is a composite diagram displayed in the same manner as in FIG.

FIG. 13 or FIG.
The resin sheet as shown in FIG.

FIG. 15 shows an apparatus in which the directions of the flow paths 41 and 42 in FIG. 6 are inclined at a predetermined angle φ with respect to the YZ plane.
FIG. 15 is a composite diagram displayed in the same manner as in FIG.

FIG. 15 or FIG.
The resin sheet as shown in FIG. The representative example of the device according to the first aspect of the present invention has been described above. As the shapes of the flow paths 41 and 42 corresponding to FIGS. 7 and 14, various shapes shown in FIGS. Can be adopted. The pitch p and height h of these irregularities are changed as appropriate.

As shown in FIG. 17, the flow paths 41 and 42 flowing into the composite flow forming section 22 can be inclined at a predetermined angle θ with respect to the XZ plane.

The outlet of the flow channel 31 can have various structures depending on the purpose. For example, FIGS. 18 and 19a,
As shown in FIG. 19 b, by attaching a base 44, the distance between the X direction and the Y direction of the cross section of the flow path (XY cross section) can be reduced toward the flow path outlet 45. By employing such a structure, it is possible to promote the formation of the uneven shape on the boundary surface between the resin layers.

Further, the outlet of the flow channel 31 may be formed so as to be unevenly distributed on one side of the flow channel 41 or 42 from the state shown in FIG.

FIG. 20 is a schematic plan view showing an example of the internal structure of the device according to the second embodiment of the present invention. The difference from the device according to the first embodiment of the present invention (FIG. 3) is that there is no flow path for resin c, and the other points are basically the same as those of the device according to the first embodiment. The same is true.

That is, this apparatus has the same composite resin flow path 21 and flow path 4 as the apparatus according to the first embodiment of the present invention.
1 and 42 are provided. Various arrangements, sizes and shapes of the portions Ln and Lm of the flow channel 41 and the portions Rn and Rm of the flow channel 42 can be used, as in the case of the device according to the first embodiment.

In the apparatus shown in FIG. 21, the portion Ln of the flow path 41 and the Rm of the flow path 42 are symmetric with respect to the XZ plane passing through the center of the composite flow forming section 22, and the Lm of the flow path 41 and the flow path Lm are 42
Are symmetrically arranged. The cross-sectional shapes of the channels 41 and 42 are the same as in FIG. When this apparatus is used, as shown in FIG. 22, a resin sheet having a polygonal line shape in the xy cross section of the boundary surface between both resin layers is manufactured. Incidentally, FIG.
FIG. 9 is a composite diagram displayed in the same manner as in FIG. 8.

As shown in FIG. 23, when an apparatus is used in which portions Rn and Rm are formed in one flow path 42 and a flow path having a constant height over the entire X direction is formed in the other flow path 41. As shown in FIG. 24 or FIG. 31c, a resin sheet whose boundary surface is biased toward the resin layer B side is manufactured. Here, FIG.
FIG. 9 is a composite diagram displayed in the same manner as in FIG.

The apparatus shown in FIG. 25 is an apparatus in which the positional relationship between the portion Ln of the flow path 41 and the flow path Rn in the X direction is slightly shifted from the apparatus shown in FIG. Using this apparatus, a resin sheet as shown in FIG. 26 or FIG. 31e is manufactured. FIG. 26 is a composite diagram displayed in the same manner as in FIG.

In the apparatus shown in FIG. 21, when the cross sections of the flow paths 41 and 42 shown in FIG. 14 are used, a small amount of the resin a and the resin b also flow in the portions Rm and Lm where the flow path height is small. A resin sheet as shown in FIG. 27 or FIG. 31a is manufactured. FIG. 27 is a composite diagram displayed in the same manner as in FIG.

Similarly to the case of FIG. 15, the directions of the flow paths 41 and 42 can be inclined by a predetermined angle φ with respect to the YZ plane as shown in FIG. Also in this case, a resin sheet as shown in FIG. 31e is manufactured.

Further, similarly to the case of FIG. 17, the flow paths 41 and 42 flowing into the composite flow forming section 22 can be inclined at a predetermined angle θ with respect to the XZ plane.

In the present invention, a wide range of thermoplastic resins can be used as the resin. The resins a, b, and c for the resin layers A, B, and C are not particularly limited as long as they have transparency. For example, various acrylic resins represented by polyethylene terephthalate, polyvinyl chloride, polystyrene, polycarbonate, polymethyl methacrylate, amorphous polyolefin, polyamide, polymethylpentene, copolymer resins or blend resins thereof, acrylonitrile / styrene copolymer And a methyl methacrylate / styrene copolymer. When transparency, weather resistance and the like are particularly required, an acrylic resin is preferable, and polymethyl methacrylate is particularly preferable.

The combination of each resin a, resin b, and resin c is appropriately selected according to the purpose. When imparting light diffusion, it is necessary to consider the difference in refractive index. Since the adhesion between the resins affects the productivity of the sheet, it is necessary to consider the adhesion between the resins. It is also important to use a combination of resins having a small difference in the melting temperature of each resin to be laminated.

In order to prevent sheet warpage, A, C, B
It is preferable that the physical properties of the resins a and b of the A layer and the B layer are the same or similar, and it is particularly preferable that the resins a and b are the same or the same resin.

In the case where the resin sheet is given a design property or a sense of depth, or in the case where it is given an optical property, it can be colored by mixing an organic or inorganic dye or pigment in each resin layer. Also, a light diffusing agent or the like can be mixed.

As shown in FIGS. 29a-i, 30a-k and 31a-h, the uneven shape of the interface between the resin layers formed on the xy cross section of the sheet is a straight line such as a polygonal line shape or a saw blade shape. A curved shape such as a shape, a semicircle, a semiellipse, a wave, an n-order parabola, and a 1 / n-order parabola can be adopted.

When imparting light diffusing property to the resin sheet, the angle α or h / p between the boundary surface having the uneven shape shown in FIGS. 30a and 31b and the sheet surface is appropriately selected in the xy cross section of the sheet. Thereby, the light diffusivity can be adjusted. Also, the repetition pitch p of the unevenness unit,
The thickness of the resin layer C or the resin layer B (that is, the values of v and t in the drawing), the thickness of the entire sheet, and the like are appropriately determined depending on the purpose of imparting the function. In addition, the value of the repetition pitch P and the value of h / p in the concavo-convex unit can be appropriately changed even in one sheet. However, from the viewpoint of achieving uniform light diffusivity, 1
It is preferable that the pitch p be the same value in one sheet.

In the resin sheet of the present invention, since the uneven shape is formed inside the sheet, the uneven shape is not damaged during use. Also, because the surface is smooth,
There is less adhesion of dust and the like as compared with a sheet having an uneven surface.

Further, the production apparatus of the present invention can produce a resin sheet having an irregular shape inside the sheet in one process, and has a remarkable effect that the production speed is extremely high.

The resin sheet of the present invention can be used as a light guide of a surface light source element. In the surface light source element, the light source is at least one end surface (yz surface) of the light guide in the x direction.
Installed in A reflecting material is appropriately applied to the other two or three end surfaces where the light source is not installed.

When the light guide is composed of two or more resin layers having different refractive indices, and the interface between the resin layers has an uneven shape, light is applied to the interface and the surface of the light guide according to Snell's law. The light propagates through the light guide while repeating reflection or refraction. Of the light that reaches the front or back surface of the light guide,
Light exceeding the critical angle exits the light guide.

[0052]

The present invention will be described below in detail with reference to examples.

Example 1 Polymethyl methacrylate (Acrypet MD, manufactured by Mitsubishi Rayon Co., Ltd.) was used as resin a and resin b.
Polycarbonate (Mitsubishi Gas Chemical, Iupilon H-3000) was prepared. The apparatus shown in FIGS. 1 to 5 was used. As the die 8 for the resin c, one having a slit gap at the outlet of the flow channel 31 of 1.7 mm was used, and as the die 9, the composite flow forming portion having the structure shown in FIGS. 6 and 7 was used. The groove portions ΔRn and ΔLn are 1 mm, the pitch P of the groove portions is 5 mm,
The width of the portions Ln and Rn was 2.5 mm (P / 2).

The shaping temperature was 260 ° C. The polymethyl methacrylate is melted in the first extruder 1 and extruded in
3 and was supplied to the die 9 and flowed into the composite flow forming part 22 from the flow path 31. At the same time, the polycarbonate is melted in the second extruder 2 and supplied to the die 8 via the extrusion flow path 14, and the composite flow forming section 2 is supplied from the flow paths 41 and 42.
2 was introduced. The width (X direction) of the composite resin flow path 21 is set to 5
0 cm, and the thickness (Y direction) was 5 mm. In the composite flow forming section, the two resins are combined to form a composite resin flow, and the composite outlet 2
3 to produce a sheet having a thickness of 5 mm and a width of 50 cm.

The obtained sheet had a smooth outer surface, no warp, a cross section having the shape shown in FIG. 30a, a pitch of irregularities of 5 mm, and h / p of 0.25. . This sheet has good appearance and light transmittance,
In addition, there was no unevenness in light diffusivity, and it was suitable for applications such as a diffusion plate.

Example 2 A die 5 having a thickness of 50 mm and a width of 50 cm was used in the same manner as in Example 1 except that the structure of the composite flow forming portion shown in FIG. 11 was used and the height of the flow path 41 was 1 mm. Was continuously shaped.

The obtained sheet has a smooth outer surface and no warp, the cross section of the resin layer C has the shape shown in FIG. 30d, the pitch of the unevenness is 5 mm, and h / p is 0. .
25. This sheet had good appearance and light transmittance, and had no unevenness in light diffusion, and was suitable for applications such as lighting covers.

Example 3 The slit gap at the outlet of the flow channel 31 was 3 mm,
2, the pitch P of the groove portions is 1.5 mm, and the portions Ln and Rn
The sheet having a thickness of 3 mm and a width of 50 cm was continuously formed in the same manner as in Example 1 except that the width of the sheet was 0.75 mm (P / 2).

The obtained sheet has a smooth outer surface and no warp, the cross section of the resin layer C has the shape shown in FIG. 30a, the pitch of the unevenness is 1.5 mm, and the h / p Was 0.25. This sheet had good appearance and light transmittance, was free from uneven light diffusion, and was suitable for applications such as a diffusion plate.

Example 4 As shown in FIG. 15, a 3 mm thick film was prepared in the same manner as in Example 1 except that the angle φ of the flow path with respect to the YZ plane was 60 degrees.
A 50 cm wide sheet was continuously shaped.

The obtained sheet has a smooth outer surface and no warp, the resin layer C has the shape shown in FIG. 30c, the pitch of the unevenness is 5 mm, and the h / p is 0.25. there were. This sheet had good appearance and light transmittance.

Embodiment 5 As shown in FIG. 9, with respect to the XZ plane including the flow path 31,
Ln of the flow path 41 and Rm of the flow path 42 are symmetrical.
5 mm thick × L in the same manner as in Example 1 except that the die 9 having a structure in which the Lm of No. 1 and the Rn of the flow path 42 were symmetrically arranged was used.
A 50 cm wide sheet was continuously shaped.

The obtained sheet had a smooth outer surface and no warp, the resin layer C had the shape shown in FIG. 29f, and the pitch of the unevenness was 5 mm. This sheet was good in both appearance and light transmittance, and was suitable for applications such as a diffusion plate.

Example 6 The thickness (Y direction) of the composite resin flow path 21 was 3 mm, the width (X direction) was 60 cm, the slit gap at the outlet of the flow path 31 was 2.6 mm, and the pitch P of the groove was 0.3 mm. A sheet having a thickness of 3 mm and a width of 60 cm was continuously formed in the same manner as in Example 1 except that the width of the portions Ln and Rn was 0.15 mm (P / 2).

The obtained sheet has a smooth outer surface without any warp, a cross section having the shape shown in FIG. 30e, a pitch P of the unevenness being 0.3 mm, and h / p being 0.15. there were. This sheet was good in both appearance and light transmittance, and had no unevenness in light diffusion, and was suitable for applications such as a diffusion plate and a light guide.

Example 7 The thickness (Y direction) of the composite resin channel 21 was 5 mm and the width (X direction) was 50 cm.
19a and 19b, the width of the outlet (X direction) is reduced to 絞 り (25 cm),
In addition, except that the thickness (Y direction) of the outlet was reduced to （(2.5 mm), the thickness was 2.5 mm × 25 mm
A sheet having a width of cm was continuously formed.

The obtained sheet had a smooth outer surface, no warp, a cross section having the shape shown in FIG. 30a, a pitch p of the unevenness was 0.15 mm, and h / p was 0.25.
Met. This sheet showed good optical characteristics like the sheet of Example 6.

Example 8 The base shown in FIGS. 18, 19a and 19b was installed at the outlet of the composite resin flow path 21, and the width (X direction) of the outlet was reduced to 1/3 (16.7 cm). Example 7 except that the thickness of the outlet (Y direction) was reduced to 1/3 (1.67 mm).
In the same manner as in the above, a sheet having a thickness of 1.67 mm and a width of 16.7 cm was continuously formed.

The obtained sheet had a smooth outer surface, no warp, a cross section having the shape shown in FIG. 30a, a pitch of irregularities of 0.10 mm, and h / p of 0.25. there were. This sheet showed good optical characteristics like the sheet of Example 6.

Example 9 The structure of the flow paths 41 and 42 was the same as that of Example 6 except that the positions of the parts Ln and Rn were shifted by P / 2 relative to each other as shown in FIG. And 3mm thickness x 5
A sheet having a width of 0 cm was continuously formed.

The obtained sheet had a smooth outer surface, no warp, and a cross section having a shape in which the pitch of the upper and lower convex portions was relatively shifted by p / 2, as shown in FIG. 30h.

Example 10 The thickness (Y direction) of the composite resin flow path was 3 mm, the thickness (Y direction) of the flow path 31 was 0.5 mm, and the pitch P of the grooves of the flow paths 41 and 42 was 0.3 mm. A sheet having a thickness of 3 mm and a width of 50 cm was continuously formed in the same manner as in Example 6, except that the widths of Ln and Rn were changed to 0.1 mm (P / 3).

The obtained sheet had a smooth outer surface, no warp, and a cross section having the shape shown in FIG. 30f.

Example 11 The thickness (Y direction) of the composite resin flow path was 3 mm, the thickness (Y direction) of the flow path 31 was 2.8 mm, and the pitch P of the groove portions of the flow paths 41 and 42 was 0.15 mm. A sheet having a thickness of 3 mm and a width of 50 cm was continuously formed in the same manner as in Example 6, except that the width of Ln and Rn was changed to 0.075 mm (P / 2).

The obtained sheet had a smooth outer surface, no warp, and a cross section having the shape shown in FIG. 30e.

Example 12 The thickness (Y direction) of the composite resin flow path was 10 mm, the thickness (Y direction) of the flow path 31 was 9.6 mm, and the pitch P of the groove portions of the flow paths 41 and 42 was 0.5 mm. A sheet having a thickness of 10 mm and a width of 50 cm was continuously formed in the same manner as in Example 6, except that the widths of Ln and Rn were changed to 0.25 mm (P / 2).

The obtained sheet had a smooth outer surface, no warp, and a cross section having the shape shown in FIG. 30e.

Example 13 The same polymethyl methacrylate as in Example 1 was used as resin a, and the same polycarbonate as in Example 1 was used as resin b. The apparatus shown in FIGS. 1, 2, 20, 21, and 22 was used. Groove portions ΔRn and ΔLn are 1 mm,
The pitch P of the grooves was 5 mm, and the width of the portions Ln and Rn was 2.5 mm (P / 2).

The shaping temperature was 260 ° C. The polymethyl methacrylate is melted in the first extruder 1 and extruded in
3 and was supplied to the die 9 and flowed into the composite flow forming part 22 from the flow path 41. At the same time, the polycarbonate was melted in the second extruder 2, supplied to the die 9 via the extrusion channel 14, and allowed to flow into the composite flow forming section 22 from the channel 42. In the composite flow forming section, the two resins are combined to form a composite resin flow, which is extruded from the composite outlet 23 and has a thickness of 5 mm ×
A 50 cm wide sheet was produced.

The obtained sheet had a smooth outer surface, no warp, a cross section having the shape shown in FIG. 31b, a vertex angle β of about 90 degrees, and a pitch of the unevenness of 5 mm. This sheet has good appearance and light transmittance, and
There was no unevenness in light diffusion, and it was suitable for applications such as a diffusion plate.

Example 14 The same as Example 13 except that the structure of the composite flow forming part shown in FIG. 28 was used as the die 9 and the height of the flow path of the flow path 41 was 1 mm, the thickness was 5 mm × 50 cm. Sheets of width were continuously shaped.

The obtained sheet had a smooth outer surface, no warp, a cross section having the shape shown in FIG. 24 or FIG. 31c, an apex angle β of about 90 degrees, and a pitch of unevenness of 5 mm. Was. This sheet showed good optical characteristics like the sheet of Example 13.

Example 15 The thickness (Y direction) of the composite resin flow path was 3 mm, and the flow path 4
The pitch P of the groove portions 1 and 42 is 2 mm, and the portions Ln and R
A sheet having a thickness of 3 mm and a width of 50 cm was continuously formed in the same manner as in Example 13 except that the width of n was 1 mm (P / 2).

The obtained sheet had a smooth outer surface as a whole, no warp, a cross section having the shape shown in FIG. 31b, a vertex angle β of about 60 degrees, and a pitch of irregularities of 2 mm. This sheet showed good optical characteristics like the sheet of Example 13.

Example 16 As shown in FIG. 28, a sheet having a thickness of 5 mm and a width of 50 cm was continuously formed in the same manner as in Example 13 except that the angle of the flow path with respect to the YZ plane was 60 degrees. .

The obtained sheet has a smooth outer surface and no warp, the resin layer C has the shape shown in FIG. 31e, the apex angle β is about 90 degrees, and the angle α is about 25 degrees. The pitch of the unevenness was 5 mm. This sheet had good appearance and light transmittance.

[0087]

[0088]

The light diffusing plate and light guide made of the resin sheet of the present invention can be applied to applications such as lighting covers, daylighting windows, building materials, road signs, signboards, and liquid crystal display devices.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of an example of a device according to a first embodiment of the present invention.

2 is a schematic side view of the device of FIG.

FIG. 3 is a schematic plan sectional view schematically showing an example of the internal structure of the apparatus shown in FIG.

FIG. 4 is a sectional view taken along the line II in FIG. 3;

FIG. 5 is a perspective view taken along the line II-II in FIG.

FIG. 6 is a schematic cross-sectional view for explaining an example of a resin flow path in the apparatus of FIG.

7 is a sectional view taken along line IV-IV in FIG.

8 is a schematic diagram showing a cross-sectional shape of a resin layer formed in the composite resin flow channel shown in FIG.

FIG. 9 is a schematic sectional view for explaining another example of the resin flow path in the apparatus of FIG.

FIG. 10 is a schematic diagram showing a cross-sectional shape of a resin layer formed in the composite resin flow channel in FIG.

FIG. 11 is a schematic sectional view for explaining still another example of the resin flow path in the apparatus of FIG.

FIG. 12 is a schematic diagram showing a cross-sectional shape of a resin layer formed in the composite resin flow channel in FIG.

13 is a schematic cross-sectional view showing another example of a cross-sectional shape of a resin layer formed in a resin flow path in the apparatus of FIG.

FIG. 14 is a schematic cross-sectional view showing the shape of the resin flow path in FIG.

FIG. 15 is a schematic cross-sectional view showing still another example of a cross-sectional shape of a resin layer formed in a resin flow path in the apparatus of FIG.

16a to 16f are schematic cross-sectional views showing other examples of the resin flow path as shown in FIG.

FIG. 17 is a schematic sectional view showing still another example of the resin flow path in the apparatus of FIG.

FIG. 18 is a schematic plan sectional view showing another example of the structure of the device according to the present invention.

19a is a schematic plan sectional view showing a base portion of the apparatus shown in FIG. 18, and FIG. 19b is a sectional view taken along line II in FIG. 19a.

FIG. 20 is a schematic plan sectional view showing an example of the internal structure of the device according to the second embodiment of the present invention.

FIG. 21 is a schematic cross-sectional view showing an example of a resin flow path in the apparatus of FIG.

FIG. 22 is a schematic diagram showing a cross-sectional shape of a resin layer formed in the composite resin flow channel in FIG.

FIG. 23 is a schematic cross-sectional view showing another example of the resin flow path in the apparatus of FIG.

24 is a schematic diagram showing a cross-sectional shape of a resin layer formed in the composite resin flow channel in FIG.

FIG. 25 is a schematic sectional view showing another example of the resin flow path in the apparatus of FIG.

26 is a schematic diagram showing a cross-sectional shape of a resin layer formed in the composite resin flow channel in FIG.

FIG. 27 is a schematic diagram showing a cross-sectional shape of a resin layer formed in a composite resin flow channel when a resin flow channel having another shape is used in FIG.

FIG. 28 is a schematic sectional view showing still another example of the resin flow path in the apparatus of FIG.

29a to 29i are cross-sectional views each showing an example of the structure of a resin sheet obtained by the apparatus of the present invention.

30a to 30k are cross-sectional views each showing another example of the structure of the resin sheet obtained by the apparatus of the present invention.

FIGS. 31a to 31h are cross-sectional views each showing another example of the structure of the resin sheet obtained by the apparatus of the present invention.

[Explanation of symbols]

 A Resin layer A B Resin layer B C Resin layer C 21 Composite resin flow path 22 Composite flow forming part 23 Composite outlet 31 Flow path for resin c 41, 42 Flow path for resin a and resin b

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hideo Yamada 20-1 Miyukicho, Otake City, Hiroshima Prefecture Examiner, Mitsubishi Rayon Co., Ltd. Otake Works Masahiro Etsuka (56) References JP-A-7-318709 (JP) , A) JP-A-5-346578 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 5/02

Claims (5)

(57) [Claims] 1. A resin sheet having a laminated structure in which a transparent resin layer C is sandwiched between a transparent resin layer A and a transparent resin layer B, wherein the outer surface is a smooth resin sheet, When the refractive index is different and the thickness direction of the sheet is y and the width direction is x, the boundary surface between the resin layers A and C and the resin layers B and C A light diffusing sheet formed of a resin sheet having at least one of the boundary surfaces of the resin sheet having an uneven shape. 2. A resin sheet having a laminated structure in which a transparent resin layer C is sandwiched between a transparent resin layer A and a transparent resin layer B, the outer surface of which is a smooth resin sheet. When the refractive index is different and the thickness direction of the sheet is y and the width direction is x, the boundary surface between the resin layers A and C and the resin layers B and C A light guide formed of a resin sheet having at least one of the boundary surfaces of the resin sheet. 3. A resin sheet having a laminated structure of a transparent resin layer A and a transparent resin layer B, having a smooth outer surface, wherein the adjacent resin layers have different refractive indices of resin, and have a thickness of the sheet. In a cross section represented by an xy plane when the direction is y and the width direction is x, the boundary surface between the resin layer A and the resin layer B has an uneven shape, and the pitch p of the uneven shape is 2 to 5 mm. In
A light diffusing sheet made of a resin sheet. 4. A resin sheet having a laminated structure of a transparent resin layer A and a transparent resin layer B, having a smooth outer surface, wherein the adjacent resin layers have different refractive indices of resin, and have a thickness of the sheet. In a cross section represented by an xy plane when the direction is y and the width direction is x, the boundary surface between the resin layer A and the resin layer B has an uneven shape, and the pitch p of the uneven shape is 2 to 5 mm. In
Light guide body made of a resin sheet that. 5. The method according to claim 2, wherein a light source is installed on at least one end face (yz plane) in the x direction of the light guide according to claim 2 and light is introduced into the light guide.