JP2014074810A - Optical sheet and production method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical sheet having an antiglare layer, in which a character or a pattern is visible by reflected light.SOLUTION: An optical sheet 1 includes a sheet 20 and an antiglare layer 21. The antiglare layer 21 is disposed on the sheet 20. The optical sheet 1 displays a character or a pattern on the surface of the antiglare layer 21. In the antiglare layer 21, a surface roughness (Ra) in an outline part 21a that is a part located at an outline of the character or the pattern is different from a surface roughness (Ra) in either side of the outline part 21a of the antiglare layer 21.

Description

  The present invention relates to an optical sheet and a manufacturing method thereof.

  Conventionally, as described in Patent Document 1, for example, an antiglare layer having a concavo-convex structure is formed on the surface of a base material to achieve anti-glare.

JP 2007-101134 A

  For example, in a cover member of a display or the like, there is a demand for anti-glare and for allowing characters and designs to be visually recognized by reflected light.

  A main object of the present invention is to provide an optical sheet having an antiglare layer, in which characters and designs are visually recognized by reflected light.

  The optical sheet according to the present invention includes a sheet and an antiglare layer. The antiglare layer is provided on the sheet. The optical sheet according to the present invention is an optical sheet on which characters or designs are displayed on the surface of the antiglare layer. In the antiglare layer, the surface roughness (Ra) of the contour portion, which is a portion located at the contour of the character or design, is different from the surface roughness (Ra) of the portions on both sides of the contour portion of the antiglare layer.

  In the antiglare layer, it is preferable that the surface roughness (Ra) of the contour portion, which is a portion located at the contour of the character or design, is smaller than the surface roughness (Ra) of the portions on both sides of the contour portion of the antiglare layer.

  In the anti-glare layer, the surface roughness (Ra) of the contour portion, which is the portion located at the contour of the character or design, and the surface roughness (Ra) of the portions on both sides of the contour portion of the anti-glare layer are different by 0.01 μm or more. Is preferred.

  The sheet may be a resin sheet having a thickness of 300 μm or less or a glass sheet having a thickness of 200 μm or less.

  The manufacturing method of the optical sheet which concerns on this invention is related with the manufacturing method of the optical sheet provided with a sheet | seat and the anti-glare layer provided on the sheet | seat, and a character or a pattern is displayed on the surface of an anti- glare layer. In the method for producing an optical sheet according to the present invention, the sheet is placed on a base having a convex portion on the surface according to a character or a pattern. A forming step of forming an antiglare layer by spraying a coating agent from above the sheet placed on the base is performed. In the forming step, the coating agent is sprayed with such a pressure that a portion that is not located on the convex portion of the sheet is curved in a concave shape.

  As the sheet, a resin sheet having a thickness of 300 μm or less or a glass sheet having a thickness of 200 μm or less may be used.

  ADVANTAGE OF THE INVENTION According to this invention, it is an optical sheet which has an anti-glare layer, Comprising: An optical sheet with which a character and a pattern are visually recognized by reflected light can be provided.

It is a typical sectional view of an optical sheet in one embodiment of the present invention. It is a schematic sectional drawing for demonstrating the manufacturing process of the optical sheet in one Embodiment of this invention. It is a schematic sectional drawing for demonstrating the manufacturing process of the optical sheet in one Embodiment of this invention. It is a graph showing the surface roughness (Ra) of a part of anti-glare layer formed in the Example.

  Hereinafter, an example of the preferable form which implemented this invention is demonstrated. However, the following embodiment is merely an example. The present invention is not limited to the following embodiments.

  Moreover, in each drawing referred in embodiment etc., the member which has a substantially the same function shall be referred with the same code | symbol. The drawings referred to in the embodiments and the like are schematically described. A ratio of dimensions of an object drawn in a drawing may be different from a ratio of dimensions of an actual object. The dimensional ratio of the object may be different between the drawings. The specific dimensional ratio of the object should be determined in consideration of the following description.

(Optical sheet 1)
FIG. 1 is a schematic cross-sectional view of an optical sheet in the present embodiment. As shown in FIG. 1, the optical sheet 1 includes a sheet 20 and an antiglare layer 21 provided on the sheet 20. The optical sheet 1 is an optical sheet on which characters and designs are displayed on the surface of the antiglare layer 21. For example, the optical sheet 1 may be an optical sheet on which at least one of characters and symbols is displayed by light reflection occurring on the surface of the antiglare layer 21. In that case, characters and designs may be displayed on the anti-glare layer 21 regardless of the reflection angle of the reflected light. In addition, the characters and symbols may be displayed only by reflected light that reflects on the antiglare layer 21 within a specific reflection angle range. For example, although characters and designs are displayed by reflected light reflected in a direction inclined with respect to the direction in which the normal on the surface of the optical sheet 1 extends, characters may be displayed depending on reflected light reflected perpendicularly to the surface of the optical sheet 1. And the symbol may not be displayed. Moreover, when the sheet | seat 20 and the anti-glare layer 21 have translucency, while displaying a character and a pattern by reflected light, a character and a pattern may be displayed also by transmitted light.

  The sheet 20 has flexibility. The sheet 20 can be composed of, for example, a resin sheet, a glass sheet, a laminate of a resin sheet and a glass sheet, or the like. The thickness of the sheet 20 is not particularly limited as long as the flexibility of the sheet 20 is not impaired. For example, when the sheet 20 is made of a glass sheet, the thickness of the sheet 20 is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. When the sheet 20 is made of a resin sheet, the thickness of the sheet 20 is preferably 300 μm or less, and more preferably 100 μm or less. The sheet 20 may have translucency or may not have translucency.

  The antiglare layer 21 is provided on the sheet 20. In the present embodiment, the antiglare layer 21 is provided on one main surface of the sheet 20, but the antiglare layer may be provided on both main surfaces of the sheet.

  The antiglare layer 21 is provided separately from the sheet 20. However, the present invention is not limited to this configuration. The antiglare layer and the sheet may be provided integrally. That is, an antiglare layer may be provided on the surface layer of the sheet.

  The anti-glare layer 21 is a layer for displaying characters and designs while preventing glare by scattering light. The antiglare layer 21 has irregularities on the surface. The antiglare layer 21 may be provided integrally as shown in FIG. 1 or may be provided in an island shape. That is, the anti-glare layer 21 may be composed of a plurality of portions separated from each other.

  The constituent material of the antiglare layer 21 is not particularly limited. The antiglare layer 21 can be made of, for example, a resin. The antiglare layer 21 may have translucency or may not have translucency.

  In the anti-glare layer 21, the surface roughness (Ra) of the contour portion 21a, which is a portion located at the contour of a character or a pattern, is different from the surface roughness (Ra) of portions on both sides of the contour portion 21a. For this reason, with respect to the antiglare layer 21, the light scattering degree at the contour portion 21a is different from the light scattering degree at both sides of the contour portion 21a. Therefore, the outline of the character or pattern comprised by the outline part 21a becomes visible.

  As described above, in the optical sheet 1, since characters and designs can be displayed in the region where the anti-glare layer 21 is provided, the characters and designs can be visually recognized by reflected light while appropriately preventing glare. Therefore, the optical sheet 1 is suitably used for, for example, a showcase or an aquarium tank.

  From the viewpoint of further improving the visibility of characters or figures, the surface roughness (Ra) of the contour portion 21a, which is the portion located at the contour of the character or design, in the anti-glare layer 21 is the difference between the portions on both sides of the contour portion 21a. It is preferably smaller than the surface roughness (Ra).

  From the viewpoint of making characters and designs more clearly visible while achieving anti-glare, the surface roughness (Ra) of the contour portion 21a and the surface roughness of portions other than the contour portion 21a of the antiglare layer 21 ( The difference from Ra) is preferably 0.01 μm or more, more preferably 0.02 μm or more, and further preferably 0.05 μm or more.

  Further, from the viewpoint of suitably preventing glare, the surface roughness (Ra) of the antiglare layer 21 including the contour portion 21a is preferably 0.05 μm or more, and more preferably 0.15 μm or more. However, if the surface roughness (Ra) of the antiglare layer 21 is too large, the image quality may be significantly lowered when the optical sheet 1 is used for a display or the like. Therefore, the surface roughness (Ra) of the antiglare layer 21 including the contour portion 21a is preferably 0.3 μm or less, and more preferably 0.25 μm or less.

  In addition, in this invention, the surface roughness of the anti-glare layer 21 is the following formula | equation (1) from the uneven | corrugated shape measured using the three-dimensional non-contact surface shape measuring system (VertScan by a biomolecule measurement laboratory company). Is a value calculated using.

Ra = (1 / L) · ∫f (x) dx (1)
However, in Formula (1),
L: measurement length f (x): the height position of the surface at the coordinate x in the scan direction.

(Method for producing optical sheet 1)
Although the manufacturing method of the optical sheet 1 is not specifically limited, For example, the optical sheet 1 can be manufactured in the following ways.

  First, the sheet 20 is prepared. Next, as shown in FIG. 2, the sheet 20 is installed on the base 10 having the convex portion 11 having a shape corresponding to the character or design on the surface (installation step). The cross-sectional shape of the convex portion 11 is preferably rectangular.

  For example, the height of the convex portion 11 is preferably 0.5 to 2.0 times the thickness of the sheet 20, and more preferably 1.0 to 1.4 times. Specifically, the height of the convex portion 11 is preferably, for example, 25 μm to 100 μm, and more preferably 50 μm to 70 μm.

  Next, as shown in FIG. 3, a coating agent 30 for forming the antiglare layer 21 is sprayed from above the sheet 20 toward the sheet 20 to form a coating film (forming process). And the anti-glare layer 21 can be formed by drying the coating film, and the optical sheet 1 can be completed.

  In the forming step, the coating agent is sprayed with such a pressure that the portion 20a of the sheet 20 that is not located on the convex portion 11 is curved in a concave shape. The shape of the antiglare layer formed by the sprayed coating agent changes depending on the angle of the sheet 20 with respect to the spraying direction of the coating agent. For this reason, the shape of the antiglare layer sprayed on the flat part of the sheet 20 is different from the shape of the antiglare layer sprayed on the curved part of the sheet 20. In particular, the sheet 20 is greatly deformed in the vicinity of the edge portion of the convex portion 11. For this reason, the shape of the antiglare layer sprayed on the part located on the vicinity of the edge part of the convex part 11 of the sheet | seat 20 differs greatly from the shape of the antiglare layer sprayed on the other part. Therefore, the surface roughness (Ra) of the antiglare layer 21 formed on the portion located on the vicinity of the edge of the convex portion 11 of the sheet 20 is the surface roughness of the portion located on both sides of the portion. Different from (Ra). Specifically, the surface roughness (Ra) of the antiglare layer 21 formed on the portion located on the vicinity of the edge of the convex portion 11 of the sheet 20 is a portion located on both sides of the portion. It becomes smaller than the surface roughness (Ra). As a result, in the anti-glare layer 21, the surface roughness (Ra) of the contour portion, which is the portion located in the contour portion 21a of the character or design, and the surface roughness (Ra) of the portions on both sides of the contour portion 21a are different. The optical sheet 1 can be manufactured suitably.

(Example)
A seal having a thickness of 70 μm was pasted on a part of the surface of the base, and a convex portion was provided on the base. Thereafter, a glass sheet having a thickness of 50 μm was placed on the base so as to cover the seal. Next, a coating agent containing silicon alkoxide was sprayed on the sheet at 0.35 MPa, and then dried to form an antiglare layer on the sheet.

  When light was incident on the obtained optical sheet from an inclined direction, a pattern corresponding to the shape of the sheet was visually recognized by the reflected light.

  Next, the surface roughness (Ra) of the portion (the portion of about 14 mm in the x direction and about 3 mm in the y direction) located on the vicinity of the edge of the seal of the antiglare layer is measured using a three-dimensional non-contact surface shape measurement system. The measurement was carried out in the following manner using VertScan (manufactured by Biomolecules Research Laboratory Co., Ltd.). First, a three-dimensional shape of a portion (a portion of about 14 mm in the x direction and about 3 mm in the y direction) located on the vicinity of the edge of the seal of the antiglare layer was measured by a three-dimensional non-contact surface shape measurement system. Next, for each pixel in the x direction, the surface roughness (Ra) was calculated with the measurement direction as the y direction and the measurement length as 3 mm. The 20-point moving average value of the calculated surface roughness (Ra) for each pixel was plotted. The obtained graph is shown in FIG.

  In the graph shown in FIG. 4, the horizontal axis is the coordinate in the x direction. The vertical axis represents the 20-point moving average value of the surface roughness (Ra). In the graph shown in FIG. 4, the region where the x coordinate is about 7000 μm or less is the portion located on the seal. The range where the x coordinate is about 7000 μm to about 8000 μm is the portion located near the edge of the convex portion of the antiglare layer. From the results shown in FIG. 4, the surface roughness of the contour (by placing the sheet on the base having the convex part and spraying the coating agent so that the sheet curves in a concave shape to form the antiglare layer ( It can be seen that an antiglare layer is obtained in which Ra) is smaller than the surface roughness (Ra) on both sides of the contour.

DESCRIPTION OF SYMBOLS 1 ... Optical sheet 10 ... Base 11 ... Convex part 20 ... Sheet 21 ... Anti-glare layer 21a ... Contour part 30 ... Coating agent

Claims (6)

Sheet,
An antiglare layer provided on the sheet;
With
An optical sheet on which letters or designs are displayed on the surface of the antiglare layer,
In the anti-glare layer, the surface roughness (Ra) of the contour portion, which is a portion located at the contour of the character or design, and the surface roughness (Ra) of the portions on both sides of the contour portion of the anti-glare layer are different. Optical sheet.   In the antiglare layer, the surface roughness (Ra) of the contour portion which is a portion located at the contour of the character or design is smaller than the surface roughness (Ra) of the portions on both sides of the contour portion of the antiglare layer, The optical sheet according to claim 1.   In the antiglare layer, the surface roughness (Ra) of the contour portion, which is a portion located at the contour of the character or design, and the surface roughness (Ra) of portions on both sides of the contour portion of the antiglare layer are 0. 0. The optical sheet according to claim 1, which differs by 01 or more.   The optical sheet according to any one of claims 1 to 3, wherein the sheet is made of a resin sheet having a thickness of 300 µm or less or a glass sheet having a thickness of 200 µm or less. A method for producing an optical sheet comprising a sheet and an antiglare layer provided on the sheet, wherein characters or designs are displayed on the surface of the antiglare layer,
Installing the sheet on a base having a convex portion on the surface according to the character or design; and
Forming step of forming the anti-glare layer by spraying a coating agent from above the sheet installed on the base,
With
The manufacturing method of the optical sheet which sprays the said coating agent with the pressure which the part which is not located on the said convex part of the said sheet | seat curves in a concave shape in the said formation process.   The method for producing an optical sheet according to claim 5, wherein a resin sheet having a thickness of 300 μm or less or a glass sheet having a thickness of 200 μm or less is used as the sheet.

Images