JP2007133209A - Surface protection sheet and transmission type screen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface protection sheet having anti-glare properties and abrasion resistance to be used in a transmission type screen and capable of being easily and inexpensively manufactured. <P>SOLUTION: The surface protection sheet 20 is provided with a base material sheet 22 having an emission side surface formed with irregularities and a hard coat layer 26 provided on the emission side surface 22a of the base material sheet 22. The hard coat layer 26 has an emission side surface 26a formed with irregularities corresponding to the irregularities of the emission side surface 22a of the base material sheet 22. The irregularities of the emission side surface 26a of the hard coat layer 26 is gentler than the irregularities of the emission side surface 22a of the base material sheet 22. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface protective sheet used for a transmission type screen, and more particularly to a surface protective sheet that has a simple structure and can be manufactured at low cost. The present invention also relates to a transmissive screen provided with such a surface protective sheet.

  Conventionally, as a rear projection display device such as a projection TV, a light source such as a CRT, a liquid crystal projector, or a DLP, and a transmission screen that receives image light from the light source from the back and displays an image on the viewer side are provided. Things are known.

  When the surface on the most observer side of such a transmission screen is a mirror surface, external light is reflected and reflected and the visibility of the transmission screen is significantly deteriorated. In order to eliminate such problems, an example in which an antiglare layer comprising a light diffusing particle and a binder resin containing the light diffusing particle is provided on the side of the most observer is disclosed in JP 2000-258613 (Patent Document 1). ). In this antiglare layer, the light diffusing particles protrude from the binder resin to the viewer side, thereby preventing regular reflection of external light and diffusing. Accordingly, the antiglare performance can be adjusted by the particle size and concentration of the light diffusing particles.

In addition, an antiglare layer formed by using a hard coat liquid as a binder resin and applying a hard coat liquid containing light diffusing particles is being developed today. That is, the surface on the most observer side of such a transmission screen has both antiglare properties and scratch resistance, and is very convenient to use.
JP 2000-258613 A

  However, when the light diffusing particles are composed of inorganic glass beads, inorganic crystal particles, or the like, there is a disadvantage that the flow path wall surface of the coating apparatus is scraped when the binder resin containing the light diffusing particles is applied. In addition, when the light diffusing particles are composed of organic fine particles or the like, the flow path wall surface of the coating apparatus is not scraped, but the light diffusive flown is deposited on the part where the flow in the flow path is bad, There is a disadvantage that the maintenance of the coating apparatus becomes complicated.

  That is, the conventional method cannot easily and inexpensively manufacture a transmission screen having both antiglare property and scratch resistance.

  The present invention has been made in consideration of such points, and is a surface protective sheet having both antiglare and scratch resistance used in a transmission screen, and can be easily and inexpensively manufactured. It aims at providing a surface protection sheet. Another object of the present invention is to provide a transmission screen having a surface protective sheet that has both antiglare properties and scratch resistance and can be easily and inexpensively manufactured.

  The present invention is a surface protection sheet used for a transmission type screen, which is a base sheet having an output side surface on which irregularities are formed, and a hard coat layer provided on the output side surface of the base sheet, A hard coat layer having an output side surface corresponding to the unevenness of the output side surface of the material sheet, and the unevenness of the output side surface of the hard coat layer is gentler than the unevenness of the output side surface of the base sheet. It is the surface protection sheet | seat characterized by the above-mentioned.

  The present invention is a surface protection sheet used for a transmission type screen, which is a base sheet having an output side surface on which irregularities are formed, and a hard coat layer provided on the output side surface of the base sheet, A hard coat layer having an emission side surface corresponding to the unevenness of the emission side surface of the material sheet, and applying a liquid resin to the base sheet and curing the applied resin to hard coat The surface protective sheet is characterized in that a layer is formed.

  This invention is a surface protection sheet characterized by the unevenness | corrugation of the output side surface of a base material sheet consisting of the unevenness | corrugation arranged regularly.

  The present invention is the surface protection sheet, wherein the unevenness on the emission side surface of the base material sheet is formed by arranging convex portions having a substantially triangular cross section in a stripe shape.

  The present invention is the surface protection sheet, wherein the unevenness on the emission side surface of the base sheet is formed by arranging square pyramid-shaped convex portions or concave portions in a square pattern.

  The surface protection sheet according to the present invention is characterized in that the projections and depressions on the emission side surface of the base sheet are formed by delta arrangement of substantially square pyramid-shaped projections or depressions.

  The present invention is the surface protection sheet, wherein the unevenness on the emission side surface of the base sheet is formed by arranging substantially hexagonal pyramidal projections or recesses in a honeycomb arrangement.

  The present invention is a transmissive screen including any one of the above-described surface protective sheets.

  The present invention is a rear projection display device including any one of the above-described surface protective sheets.

  According to the surface protective sheet of the present invention, the emission side surface of the surface protective sheet is made of a hard coat layer, and thus has scratch resistance. In addition, since the emission side surface of the hard coat layer has irregularities, external light is diffusely reflected, and reflection of external light can be significantly reduced. Furthermore, such a surface protection sheet can be manufactured easily and inexpensively.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 and 2 are views showing an embodiment of a surface protective sheet and a transmission screen according to the present invention. 1 is a cross-sectional view along the width direction showing the surface protection sheet 20, and FIG. 2 is a cross-sectional view along the width direction showing the transmissive screen 10 including the surface protection sheet 20 shown in FIG. .

  Such a transmissive screen 10 is used as a screen of the rear projection display device 1 as shown in FIG. 11 so that the image light projected from the light source 3 and reflected by the mirror 5 is projected onto the transmissive screen 10. It has become.

  As shown in FIG. 2, the transmissive screen 10 according to the present embodiment includes a Fresnel lens sheet 12 provided closest to the light source 3, a field expansion lens sheet 14 provided on the viewer side of the Fresnel lens sheet 12, And a surface protective sheet 20 bonded to the exit side surface 14a of the field-enlargement lens sheet 14 via an adhesive layer.

  Of these, the Fresnel lens sheet 12 has a large number of Fresnel lens elements 13 arranged concentrically, refracts the image light enlarged and projected from the light source 3, and transmits the light in a direction substantially orthogonal to the Fresnel lens sheet 12. It comes out. However, the Fresnel lens sheet 12 is not essential and can be omitted depending on the performance required for the transmission screen 10.

  As shown in FIG. 2, in the present embodiment, the field-enlargement lens sheet 14 is a lenticular lens sheet, and diffuses light incident from the Fresnel lens sheet 12 side in the width direction (the left-right direction in FIG. 2). A large number of semi-columnar lens elements 15 are provided. In other words, the field expansion lens sheet 14 is a sheet for expanding the viewing angle by diffusing video light in the width direction.

  However, the field expansion lens sheet is not limited to the lenticular lens sheet as long as the image light can be diffused. For example, as shown in FIG. 3, the field of view enlargement having a sheet-like base 17 and a low-refractive-index part 18 made of a material having a lower refractive index than that of the sheet-like base 17 provided on the exit surface side of the sheet-like base 17. A lens sheet 16 can also be used. In this field expansion lens sheet 16, the interface between the sheet-like base portion 17 and the low refractive index portion 18 becomes a reflection surface, and image light is diffused in the width direction.

  Next, the surface protection sheet 20 will be described.

  As shown in FIG. 2, the surface protection sheet 20 is disposed on the most observer side of the transmission screen 10, and forms an emission side surface 10 a of the transmission screen 10. As shown in FIG. 1, such a surface protective sheet 20 is provided on a base sheet 22 having an output side 22 a on which irregularities arranged regularly are formed, and on the output side 22 a of the base sheet 22. And a hard coat layer 26 having an emission side surface 26a on which irregularities corresponding to the irregularities of the emission side surface 22a of the base sheet 22 are formed. The unevenness of the exit side surface 26a of the hard coat layer 26 is gentler than that of the exit side surface 22a of the base sheet 22, in other words, more gently, and in other words, less uneven.

  Here, the hard coat layer 26 is formed of a material that has a hardness (measured by a pencil hardness test in accordance with JIS K5600-5-4) equal to or higher than that of the base sheet 22. That is, since the emission side surface 10a of the transmission type screen 10 is formed by the hard coat layer 26, even if the emission side surface 10a of the transmission type screen 10 is wiped or rubbed for some reason, The transmission screen 10 can be prevented from being damaged. Further, since the unevenness is formed on the emission side surface 26a of the hard coat layer 26, it is possible to prevent the external light from being regularly reflected, and the observer can visually recognize the reflection of the external light. Images with good characteristics can be observed.

  As shown in FIG. 1, in the present embodiment, a convex portion 23 having a substantially triangular cross section and extending in the vertical direction (the depth direction of the paper surface in FIG. 1) is formed on the emission side surface 22 a of the base sheet 22 in the width direction. Regular irregularities that are arranged in a stripe pattern without gaps are formed. Accordingly, by forming the base sheet 22 and the hard coat layer 26 from resins having different refractive indexes, a desired optical effect, for example, image light is applied to the interface between the base sheet 22 and the hard coat layer 26. Effects such as spreading and widening the viewing angle can also be exhibited.

  In addition, such a base material sheet 22 can be formed by extruding resin, and can be manufactured inexpensively using conventional equipment. The resin forming the base sheet preferably has high transparency and good adhesion to the hard coat layer 26 described later. Specifically, an extrudable thermoplastic resin such as an acrylic resin, a methacrylic resin, or a styrene resin can be used as the resin.

  Further, the shape and the arrangement pitch of the protrusions 23 having a substantially triangular cross section are such that the arrangement pitch of the protrusions 23 is 3 μm to 30 μm so that the base sheet 22 can be easily formed by extrusion. Is preferably in the range of 5 to 30 μm. However, as long as the reflection of external light can be suppressed, the range is not particularly limited, and in particular, the interface between the base sheet 22 and the hard coat layer 26 expresses a desired optical effect. May be changed as appropriate according to special circumstances such as when

  On the other hand, the hard coat layer 26 can be formed by applying a liquid resin made of an ionizing radiation curable resin, a thermoplastic resin, or the like to the emission side surface 22a of the base sheet 22 and curing the applied resin. . In this case, by applying the resin with the emission side surface 22a of the base sheet 22 facing upward, the resin is recessed from the protruding peak (projection) 24a on the output side surface 22a of the base sheet 22. It hardens | cures, flowing on the trough part (concave part between the convex part 23 and the convex part 23) 24b. That is, as shown in FIG. 1, the hard coat layer 26 on the peak portion 24a of the base sheet 22 tends to be thin and the hard coat layer 26 on the valley portion 24b tends to be thick. The unevenness of the emission side surface 26 a can be made gentler than the unevenness of the emission side surface of the base sheet 22. In this way, the observer can observe a natural image without a rough feeling by smoothing the unevenness of the emission side surface 26a of the hard coat layer 26, that is, the unevenness of the outermost observation side surface 10a of the transmissive screen 10, and eliminating the sharp edges. Can do.

  As a method for applying the liquid resin, methods such as spin coating, die coating, dip coating, bar coating, flow coating, roll coating, and gravure coating can be used. In addition, the method of curing the resin can be appropriately set according to the type of the resin. For example, when an ionizing radiation curable resin is used, the resin is irradiated with an electron beam or ultraviolet rays, thereby thermoplastic resin. When is used, it can be cured by heating the resin.

  Therefore, any process can be performed using the existing equipment as it is, and as a result, such a surface protection sheet 20 can be manufactured very inexpensively. In particular, in the step of applying a liquid resin, since the light diffusing particles are not included in the resin, the flow path wall surface of the coating apparatus may be shaved or the light diffusive flow element in the flow path. There will be no inconvenience of depositing. Therefore, the maintenance of the coating apparatus is easy and the maintenance cost is low.

  In addition, it is preferable that the surface hardness of such a hard-coat layer 26 is 3H or more in the pencil hardness test based on JISK5600-5-4. Further, the surface hardness of the hard coat layer 26 also depends on its film thickness. Therefore, from such a viewpoint, the film thickness of the hard coat layer 26 is preferably in the range of 5 μm to 20 μm.

  In order to improve the antiglare property, it is effective to select a resin that forms the hard coat layer 26 and the base sheet 22 so as to satisfy the following formula (1). When the expression (1) is satisfied, the external light entering the hard coat layer 26 is reflected at the interface between the base sheet 22 and the hard coat layer 26 and is emitted from the hard coat layer 26 to the viewer side again. Can be suppressed.

Refractive index of base sheet> refractive index of hard coat layer (1)
As described above, according to the present embodiment, the most observing side of the transmissive screen 10 is provided on the base sheet 22 having the output side surface 22a with the unevenness formed on the output side surface 22a of the base sheet 22. And a hard coat layer 26 having an output side surface 26a on which unevenness corresponding to the unevenness of the output side surface 22a of the base material sheet 22 is formed. The unevenness of the exit side surface 26 a of the hard coat layer 26 is gentler than the unevenness of the exit side surface 22 a of the base sheet 22. That is, the outermost observation side surface 10a of the transmission screen 10 is composed of the emission side surface 26a of the hard coat layer 26 on which gentle irregularities are formed. Therefore, the transmissive screen 10 has scratch resistance that is difficult to be scratched even if it is wiped or rubbed for some reason, and prevents reflection of external light by preventing regular reflection of external light. It has anti-glare properties that provide good visibility. In addition, since the emission side surface 26a of the hard coat layer 26 has gentle irregularities with no sharp edges, the image displayed on the transmissive screen 10 is a natural image with no roughness.

  In addition, the surface protection sheet 20 of such a transmission screen 10 is formed by extruding the base sheet 22, applying a liquid resin to the emission side surface 22 a of the base sheet 22, and curing the applied resin. Can be manufactured. Therefore, the existing equipment can be used as it is, and as a result, such a surface protection sheet 20 can be manufactured very inexpensively. In particular, in the step of applying a liquid resin, since the light diffusing particles are not included in the resin, the flow path wall surface of the coating apparatus may be shaved or the light diffusive flow element in the flow path. There is no inconvenience of depositing. Therefore, the maintenance of the coating apparatus is easy and the maintenance cost is low.

  Furthermore, according to the present embodiment, unlike the irregular uneven surface when the light diffusing particles are contained, the unevenness of the emission side surface 22a of the base sheet 22 is composed of intentionally arranged unevenness. Accordingly, by forming the base sheet 22 and the hard coat layer 26 from resins having different refractive indexes, a desired optical effect, for example, image light is applied to the interface between the base sheet 22 and the hard coat layer 26. Effects such as spreading and widening the viewing angle can also be exhibited. Further, by appropriately adjusting the configuration of the unevenness of the emission side surface 22a of the base sheet 22, an optical effect that cannot be realized by random unevenness, for example, directivity such as particularly preventing reflection of external light coming from the side surface is given. In addition, it is possible to develop effects such as providing a distribution of the antireflection effect within the screen surface.

  In the present embodiment, the unevenness of the emission side surface 22a of the base sheet 22 has been illustrated by arranging the convex portions 23 having a substantially triangular cross section in a stripe shape without a gap, but the present invention is not limited thereto. However, for example, as shown in FIGS.

  Hereinafter, modified examples will be described with reference to FIGS. 4 to 10 are different from the embodiment described with reference to FIGS. 1 and 2 except that the configuration of the emission side surface 22a of the base sheet 22 is different. 4 to 10, the same parts as those in the embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  First, modified examples shown in FIGS. 4 to 7 will be described. Among these, FIG. 4 is a perspective view showing the recess 23 a of the emission side surface 22 a of the base sheet 22. As shown in FIG. 4, the concave portion 23a in the present modification has a substantially regular quadrangular pyramid shape. The concave and convex portions of the emission side surface 22a of the substrate sheet 22 may be formed by arranging the concave portions 23a squarely without gaps (FIG. 5) or by arranging the concave portions 23a delta without gaps (FIG. 6). . Here, the square array is an array in which concave portions 23a having substantially the same shape are arranged in a straight line in both the vertical direction and the width direction, as shown in FIG. In addition, as shown in FIG. 6, the delta arrangement includes the recesses 23 a having substantially the same shape arranged in a straight line in either the vertical direction or the width direction, and arranged in adjacent rows. This is an arrangement in which the recesses 23a are arranged with a substantially half arrangement pitch. In addition, although the example which forms an unevenness | corrugation in the output side 22a of the base material sheet 22 by the recessed part 23a which consists of a substantially regular quadrangular pyramid shape in this modification was shown, it is not restricted to this, From a substantially regular quadrangular pyramid shape as shown in FIG. By forming the convex portions 23b to be square without gaps (FIG. 5), or by arranging the convex portions 23b with delta without gaps (FIG. 6), irregularities may be formed on the emission side surface 22a of the base sheet 22. it can.

  Next, modified examples shown in FIGS. 8 to 10 will be described. Among these, FIG. 8 is a perspective view showing the concave portion 23 c of the emission side surface 22 a of the base sheet 22. As shown in FIG. 8, the recess 23c in the present modification has a substantially regular hexagonal pyramid shape. Unevenness may be formed on the emission side surface 22a of the base sheet 22 by arranging such recesses 23c in a honeycomb arrangement without gaps (FIG. 9). Here, as shown in FIG. 9, the honeycomb arrangement is an arrangement in which the concave portions 23c having substantially the same shape are arranged without gaps around the concave portions 23c having a substantially hexagonal pyramid shape. In addition, although the example which forms an unevenness | corrugation in the output side 22a of the base material sheet 22 by the recessed part 23c which consists of a substantially regular hexagonal cone shape in this modification was shown, it is not restricted to this, From a substantially regular hexagonal cone shape as shown in FIG. By arranging the convex portions 23d to be honeycomb without gaps, it is possible to form irregularities on the emission side surface 22a of the base sheet 22.

  Further, in the present embodiment and the above-described modification example, the unevenness of the emission side surface 22a of the base sheet 22 is made of regularly arranged unevenness, that is, an example of regularly arranged concave or convex portions. However, the present invention is not limited to this, and irregularities may be formed on the emission side surface 22a of the base sheet 22 by irregularities arranged irregularly. As such an example, a so-called mat surface in which concave portions or convex portions having the same or different shapes, or concave portions and convex portions are randomly provided on the emission side surface 22a of the base sheet 22 can be considered.

  Furthermore, in the present embodiment and the modified example, as shown in FIGS. 2 and 3, an example is shown in which the surface protection sheet 20 is bonded to the field-of-view magnification lens sheets 14 and 16 through an adhesive layer. However, the transmissive screen 10 can be configured without adhering the surface protection sheet 20 and the field-enlargement lens sheets 14 and 16 together.

  A transmissive screen was manufactured by providing a surface protection sheet shown in FIG. 1 on an existing screen having a Fresnel lens and a lenticular lens and having an aspect ratio of 9:16.

  The base sheet of the surface protective sheet was formed by extruding a copolymer resin of methacrylic resin and styrene resin. Protrusions having a triangular cross section with a height of 10 μm and an arrangement pitch of 10 μm were formed on the emission side surface of the base sheet without gaps.

  The hard coat layer of the surface protective sheet was formed by applying an ultraviolet curable hard coat agent on the emission side surface on the base sheet by die coating, and curing the applied hard coat agent by irradiation with ultraviolet rays. The unevenness on the emission side surface of the hard coat layer became gentler than the unevenness on the emission side surface of the base sheet. The film thickness of the hard coat layer was about 5 μm at the thinnest place, that is, on the peak portion of the convex portion of the base sheet. Moreover, the film thickness of the hard coat layer was about 7 μm on the thickest place, that is, on the valley between the convex portions of the base sheet.

  Such a transmissive screen was attached to the rear projection display device shown in FIG. 11, and image light was projected by a liquid crystal projector (liquid crystal light source). On the transmissive screen, an image with good visibility that the external light was not visible was displayed. In addition, when observing the image, the unevenness of the surface on the most observer side of the transmissive screen (the emission side surface of the hard coat layer) is not worrisome, so that a natural image without a rough feeling can be observed. I was able to.

Sectional drawing which shows one Embodiment of the surface protection sheet by this invention. Sectional drawing which shows the transmission type screen provided with the surface protection sheet shown in FIG. The figure which shows the modification of a transmissive screen. The perspective view which shows the recessed part provided in the output side of a base material sheet. The figure which shows the modification of the arrangement | sequence of the recessed part or convex part of a base material sheet. The figure which shows the modification of the arrangement | sequence of the recessed part or convex part of a base material sheet. The perspective view which shows the modification of the convex part provided in the output side surface of a base material sheet. The perspective view which shows the modification of the recessed part provided in the output side surface of a base material sheet. The figure which shows the modification of the arrangement | sequence of the recessed part or convex part of a base material sheet. The perspective view which shows the modification of the convex part provided in the output side surface of a base material sheet. The perspective view which shows the rear projection type display apparatus provided with the transmissive screen.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Transmission type screen 20 Surface protection sheet 22 Base material sheet 22a Output side surface 26 Hard coat layer 26a Output side surface 23, 23b, 23d Convex part 23a, 23c Concave part

Claims (9)

A surface protective sheet used for a transmission screen,
A base sheet having an exit side surface on which irregularities are formed;
A hard coat layer provided on the emission side surface of the base sheet, and a hard coat layer having an emission side surface formed with irregularities corresponding to the irregularities of the emission side surface of the base sheet,
The surface protective sheet is characterized in that the unevenness on the emission side surface of the hard coat layer is smoother than the unevenness on the emission side surface of the base sheet. A surface protective sheet used for a transmission screen,
A base sheet having an exit side surface on which irregularities are formed;
A hard coat layer provided on the emission side surface of the base sheet, and a hard coat layer having an emission side surface formed with irregularities corresponding to the irregularities of the emission side surface of the base sheet,
A surface protective sheet in which a hard coat layer is formed by applying a liquid resin to a base sheet and curing the applied resin.   The surface protective sheet according to claim 1, wherein the unevenness on the emission side surface of the base material sheet is composed of unevenness regularly arranged.   The surface protection sheet according to any one of claims 1 to 3, wherein the unevenness on the emission side surface of the base sheet is formed by arranging convex portions having a substantially triangular cross section in a stripe shape.   The surface protection sheet according to any one of claims 1 to 3, wherein the projections and depressions on the emission side surface of the base sheet have substantially square pyramidal projections or depressions arranged in a square.   The surface protection sheet according to any one of claims 1 to 3, wherein the projections and depressions on the emission side surface of the base sheet are formed by delta arrangement of convex portions or concave portions having a substantially quadrangular pyramid shape.   The surface protection sheet according to any one of claims 1 to 3, wherein the unevenness on the emission side surface of the base material sheet is formed by arranging substantially hexagonal pyramidal projections or depressions in a honeycomb arrangement.   A transmissive screen comprising the surface protective sheet according to claim 1.   A rear projection display device comprising the surface protective sheet according to any one of claims 1 to 7.

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