JP2017009844A - Screen and image projection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screen which offers enhanced image visibility when used under bright external light, such as sunlight and illumination light, by suppressing glare caused by the external light.SOLUTION: A screen has a light selection layer comprising one or more diluent resin sheets 1A and 1B, each having protrusions on one surface thereof, with an air layer 9 and repetitively and alternately arranged right-to-left downslope surfaces 9a and left-to-right downslope surfaces 9b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a screen and an image projection system that can be used under bright light such as sunlight and illumination light.

  As a screen used when projecting an image with a projector such as a liquid crystal projector, there are a reflective screen, a transmissive screen, and the like. For example, a screen described in Patent Document 1 is known.

JP 2002-169224 A

  In recent years, there has been a demand for a screen that can be used not only in a dark room but also in bright light such as sunlight or illumination light. However, with conventional screens, when used under bright light such as sunlight or illumination light, the light felt glare and the image visibility was likely to be low. The use of was difficult.

The present invention includes the inventions described in the following [1] to [6].
[1] A screen having a light selection layer in which one or a plurality of shaping resin sheets having convex portions on one surface are arranged;
[2] The screen according to [1], wherein the height of the convex portion is 1 μm or more and 100 μm or less, and the pitch interval is 10 μm or more and 1 mm or less.
[3] The screen according to [1] or [2], wherein the convex portion is a triangular convex portion whose cross-sectional shape is a triangle.
[4] When a straight line connecting both ends of the bottom of the triangular convex portion is a triangle base, one base angle of the triangle is more than 20 ° and not more than 45 °, and the other base angle is more than 0 ° and 89 °. The screen according to [3], which is not more than °;
[5] The screen according to any one of [1] to [4] further including a reflective layer [6] The screen according to any one of [1] to [5], and the screen An image projection system comprising a projector that projects an image.

  Even when the screen of the present invention is used under bright light such as sunlight or illumination light, the image projected on the screen has high visibility, so it can be used outdoors in the daytime or in a bright room.

It is a schematic diagram of the cross-sectional shape of the light selection layer which concerns on one Embodiment of this invention. It is a schematic diagram of the manufacturing apparatus used for the manufacturing method of the shaping resin sheet which concerns on one Embodiment of this invention. It is a schematic diagram of the cross-sectional shape of the reflective screen which concerns on one Embodiment of this invention. It is a schematic diagram of the cross-sectional shape of the transmission type screen which concerns on one Embodiment of this invention.

  The screen of the present invention has a light selection layer in which one or a plurality of shaping resin sheets having convex portions on one surface are arranged. The light selective layer is a layer that can selectively transmit or shield light according to the incident angle of light. As the light selection layer, preferably, the convex portion is formed so as to totally reflect the light beam that travels beyond the set angle, and more preferably, the shaping resin sheet having the convex portion on one surface. Is formed, or a molded resin sheet having a convex portion on one surface is a molded resin sheet having a convex portion on one surface of a pair, The surface (hereinafter, sometimes referred to as a shaping surface) having a surface is disposed so as to face each other.

<Shaping resin sheet>
The shaped resin sheet is a resin sheet having a convex portion on one surface, and is usually obtained by melt extrusion molding a resin. Usually, the surface opposite to the shaping surface is a flat surface. FIG. 1 shows a schematic diagram of a cross-sectional shape of a light selection layer according to an embodiment of the present invention in which two such molded resin sheets are arranged.

  The resin may be any resin that can be melt-extruded, and examples thereof include thermoplastic resins. Examples of the thermoplastic resin include styrene resin, (meth) acrylic resin, polyethylene resin, polypropylene resin, cyclic olefin resin, acrylonitrile-butadiene-styrene (ABS) resin, polyethylene terephthalate (PET) resin, polycarbonate (PC ) Resin, etc. Among them, (meth) acrylic resins are preferred from the viewpoint of excellent transparency and weather resistance.

  The (meth) acrylic resin is not particularly limited. For example, a (meth) acrylic polymer having a monomer unit derived from a (meth) acrylic monomer, a single monomer derived from a (meth) acrylic monomer Examples thereof include a copolymer having a body unit and a monomer unit derived from a monomer other than a (meth) acrylic monomer. Examples of the (meth) acrylic monomer include (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylonitrile and the like. The (meth) acrylic monomers may be used alone or in combination of two or more. In the present specification, the term “(meth) acryl” means “acryl” or “methacryl”.

  Examples of monomers other than (meth) acrylic monomers include maleic anhydride and styrene.

  The (meth) acrylic resin is preferably a methacrylic resin from the viewpoint of excellent hardness, weather resistance, transparency and visibility, and more preferably a total amount of monomer units contained in the polymer of 100 weight. %, A polymer having 50% by weight or more of monomer units derived from a methacrylic acid ester, for example, a methacrylic acid ester polymer, a monomer unit derived from 50% by weight or more of a methacrylic acid ester, and And a copolymer having 50% by weight or less of a monomer unit derived from a monomer other than a methacrylic acid ester. The copolymer preferably has a monomer unit derived from 70% by weight or more of a methacrylic acid ester and a monomer unit derived from a monomer other than 30% by weight of a methacrylic acid ester. More preferably, it is a copolymer having a monomer unit derived from 90% by weight or more of a methacrylic acid ester and a monomer unit derived from a monomer other than 10% by weight of a methacrylic acid ester. (However, the total amount of monomer units contained in the copolymer is 100% by weight).

  Examples of the methacrylate ester include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, N-octyl methacrylate, n-nonyl methacrylate, isononyl methacrylate, decyl methacrylate, undecyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, lauryl methacrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, etc. It is done. Among these, a methacrylic acid ester having an alkyl group having 1 to 8 carbon atoms is preferable, and methyl methacrylate is more preferable. A methacrylic acid ester may be used independently and may use 2 or more types together.

  Examples of monomers other than methacrylic acid esters include acrylic acid esters, unsaturated nitriles, ethylenically unsaturated carboxylic acid hydroxyalkyl esters, ethylenically unsaturated carboxylic acid amides, ethylenically unsaturated acids, and ethylenically unsaturated sulfonic acid esters. , Ethylenically unsaturated alcohols and esters thereof, ethylenically unsaturated ethers, ethylenically unsaturated amines, ethylenically unsaturated silane compounds, aliphatic conjugated dienes, and the like. Among these, acrylic acid esters are preferable. Monomers other than methacrylic acid esters may be used alone or in combination of two or more.

  The polymer having 50% by weight or more of a monomer unit derived from a methacrylic acid ester is a methyl methacrylate homopolymer or a monomer unit derived from 50% by weight or more and 99.9% by weight or less of methyl methacrylate. And a copolymer having 0.1 to 50% by weight of monomer units derived from (meth) acrylic acid esters other than methyl methacrylate. Further, the copolymer is preferably a monomer unit derived from 70% by weight or more and 99.9% by weight or less of methyl methacrylate and 0.1% by weight or more and 30% by weight or less of methyl methacrylate. A copolymer having a monomer unit derived from (meth) acrylic acid ester, and more preferably 90% by weight or more and 99.9% by weight or less of a monomer unit derived from methyl methacrylate; 1% by weight or more and 10% by weight or less of a monomer unit derived from a (meth) acrylic acid ester other than methyl methacrylate (however, the monomer unit contained in the copolymer) The total amount is 100% by weight.).

  Examples of the method for producing the (meth) acrylic resin include an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, a liquid injection polymerization method (cast polymerization method), and the like.

  The polymerization reaction is started by light irradiation or using a polymerization initiator, and it is preferable to use a polymerization initiator. Examples of the polymerization initiator include azo initiators (for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile)), peroxide initiators ( Lauroyl peroxide, benzoyl peroxide, etc.), redox initiators in which organic peroxides and amines are combined, and the like. The addition amount of the polymerization initiator is preferably 0.01 parts by weight or more and 1 part by weight or less, more preferably 0.01 parts by weight with respect to 100 parts by weight of the monomer used in the production of the (meth) acrylic resin. More than 0.5 parts by weight. Further, a chain transfer agent for controlling the molecular weight (a linear or branched alkyl mercaptan compound such as methyl mercaptan, n-butyl mercaptan, t-butyl mercaptan, etc.), a crosslinking agent or the like may be added.

The shaping resin sheet 1 may be used alone or in combination of two or more. For example, the (meth) acrylic resin may be used alone, or the (meth) acrylic resin and another resin may be used in combination. The other resin may be a (meth) acrylic resin having a monomer composition different from that of the (meth) acrylic resin, or a (meth) acrylic resin such as a styrene resin. Resins of different species may be used. In addition, various commonly used additives may be added to the (meth) acrylic resin as long as the effects of the present invention are not impaired. Examples of the additive include a stabilizer, an antioxidant, an ultraviolet absorber, a light stabilizer, a colorant, a foaming agent, a lubricant, a release agent, an antistatic agent, a flame retardant, a polymerization inhibitor, and a flame retardant aid. And reinforcing agents. These additives may be used alone or in combination of two or more.
When the additive is added, the amount added is preferably 0.005 parts by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic resin.

  When a (meth) acrylic resin is used as the resin constituting the above-mentioned shaped resin sheet 1, the impact resistance of the obtained shaped resin sheet 1 can be improved by blending a rubbery polymer. Examples of the rubber-like polymer include (meth) acrylic multilayer polymer, 5 to 80 parts by weight of the rubbery polymer and ethylenically unsaturated such as (meth) acrylic unsaturated monomer. Examples thereof include a graft copolymer obtained by graft polymerization of 20 parts by weight or more and 95 parts by weight or less of a monomer. The (meth) acrylic multilayer structure is composed of a plurality of layers mainly composed of a (meth) acrylic resin, for example, a rubber elastic layer or an elastomer layer containing a (meth) acrylic resin. A two-layer structure having a hard layer mainly composed of alkyl (meth) acrylate, a rubber elastic layer or elastomer layer containing (meth) acrylic resin, and both sides of the rubber elastic layer And a three-layer structure having a hard layer mainly composed of alkyl (meth) acrylate. Preferably, it has a rubber elastic layer or an elastomer layer in a proportion of 20 wt% to 60 wt% with respect to 100 wt% of the (meth) acrylic multilayer structure polymer, and has a hard layer at the outermost portion. Is good. Moreover, the structure which further contains a hard layer as an innermost layer may be sufficient.

  The blending amount when blending the rubbery polymer is preferably 3 parts by weight or more and 150 parts by weight or less, more preferably 5 parts by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic resin. It is. When the amount of the rubber-like polymer is too large, the surface hardness decreases, which is not preferable.

  The above-mentioned convex part is preferably a convex part whose cross-sectional shape is a triangle in order to totally reflect the light beam that travels beyond the set angle, and in particular, a straight line between the opposing edges of the shaping resin sheet 1. It is preferable that the shape of the orthogonal cross section which appears when it cuts along the direction perpendicular | vertical to the longitudinal direction is a triangular convex part. The apex angle of the triangle may be an arc having a curvature.

  When a straight line connecting both ends of the bottom of the triangular convex portion is the base of the triangle, the base angle 2 of the triangle is one base angle 2a (hereinafter, The first base angle 2a) may be more than 20 ° and 45 ° or less, and the other base angle 2b (hereinafter may be called the second base angle 2b) may be more than 0 ° and 89 ° or less. It is preferable that the first base angle 2a is 20 ° to 40 °, and the second base angle 2b is more preferably 1 ° to 85 °. If the first base angle 2a is larger than 45 °, it may be difficult to recognize the image projected on the screen. At this time, it is necessary to install the shaping resin sheet 1 perpendicularly to the ground so that the first base angle 2a is at the top and the second base angle 2b is at the bottom.

  The height (H) of the convex portion is preferably 1 μm or more and 1 cm or less, and more preferably 5 μm or more and 1 cm or less. If the height (H) of the convex portion is less than 1 μm, it may be difficult to mold the convex portion on the surface of the resin sheet, and if it exceeds 1 cm, the thickness of the screen becomes too thick. The pitch interval (P), which is the distance between the apexes of the convex portions, is preferably 10 μm or more and 10 cm or less, and more preferably 50 μm or more and 10 cm or less. If the pitch interval (P) is less than 10 μm, it may be difficult to form a convex portion on the surface of the resin sheet, and if it exceeds 10 cm, the thickness of the screen becomes too thick.

  The thickness of the shaping resin sheet 1 is preferably 1 μm or more and 1 cm or less, and more preferably 10 μm or more and 1 cm or less. If it is thinner than 1 μm, it may break, and if it is thicker than 1 cm, it will become heavy and may be inappropriate as a screen. In the present specification, the thickness of the shaping resin sheet means the distance from the surface facing the surface having the convex portion to the tip of the convex portion, and corresponds to, for example, L in FIG.

The shaped resin sheet 1 of the present invention is preferably transparent when visually observed. As an index of transparency, when the thickness of the molded resin sheet 1 of the present invention is 3 mm, the total light transmittance of the molded resin sheet 1 measured according to JIS K7361-1 is preferably 80% or more. More preferably, it is 90% or more.
As another index of transparency, the haze of the shaped resin sheet 1 measured according to JIS K7136 is preferably 10% or less, more preferably 5% or less.

  Hereafter, the manufacturing method and manufacturing apparatus of the shaping resin sheet 1 of this invention are demonstrated in detail with reference to FIG.

<Method for producing shaped resin sheet>
The method for producing the shaped resin sheet 1 of the present invention includes a sheet-like material extrusion step of continuously extruding a resin from a die in a heated and melted state and extruding it into a sheet shape, and a sheet-like material as a first pressing roll and a second pressing roll And a pressing step for sandwiching the sheet-like material between the second pressing roll and a shaping roll, and a molding step for sandwiching the conveyed sheet-like material between the second pressing roll and a shaping roll. including. According to this manufacturing method, since a convex shape is imparted to the surface of the resin sheet in the process of molding the resin sheet, secondary processing for imparting the convex shape to the resin sheet surface is unnecessary, and easy molding is performed. A resin sheet 1 is obtained.

<Sheet-like material extrusion process>
In the sheet-like material extrusion step, the resin is continuously extruded from the die in a heated and melted state to produce a sheet-like material.

  As the resin used in the production method of the present invention, the thermoplastic resin exemplified in the above-mentioned shaping resin sheet 1 can be used, and among these, (meth) acrylic resins are preferably used.

  Additives such as ultraviolet absorbers, heat stabilizers, antistatic agents, and light diffusing agents may be added to the resin.

  As the die 4 for continuously extruding the resin in a heated and melted state, a metal T-die that is the same as that used in a normal extrusion method is used. In order to extrude the resin from the die in a heated and melted state, an extruder is used in the same manner as in a normal extrusion molding method. The extruder may be a single screw extruder or a twin screw extruder. The resin is heated in an extruder, sent to a die in a molten state, and extruded. The resin extruded from the die is continuously extruded as a sheet.

  The sheet-like material may be a single layer or two or more layers. When the sheet-like material is a single layer, when the resin is extruded from the die in a heated and melted state, one type of resin may be supplied to the die and extruded, and in the case of two or more layers, two or more types of resin are added. You may supply to a die | dye and co-extrusion in the laminated state. In order to perform co-extrusion in a state where two or more kinds of resins are laminated, for example, a known two-type three-layer distribution type feed block may be used, and the resin may be supplied to the die via this.

<First pressing step>
As shown in FIG. 2, the sheet-like material obtained in the sheet-like material extrusion step is simultaneously sandwiched between the first pressure roll 5a and the second pressure roll 5b in the first pressure step. As the first pressing roll and the second pressing roll, a metal roll usually made of a metal such as stainless steel or steel is used, and its diameter is usually 100 mm or more and 500 mm or less. When metal rolls are used as the first and second pressing rolls, the surface thereof may be subjected to plating treatment such as chrome plating, copper plating, nickel plating, nickel-phosphorus plating, or the like. Further, the surface of the pressing roll may be a mirror surface, or may be a transfer surface provided with unevenness such as embossing if it is not necessary to transfer accurately.

<Conveying process>
A conveyance process is a process of conveying according to rotation of the 2nd press roll in the state where the sheet-like object was stuck to the 2nd press roll.

  In the first pressing step and the conveying step, the sheet-like material has a temperature lower than that of the heated and melted state extruded from the die due to cooling due to contact with the pressing roll and cooling due to contact with outside air. Thus, in a state where the temperature is lower than that in the heat-melted state, the sheet-like material is conveyed and used for the next second pressing step. In addition, it is desirable that the pressing roll has a temperature adjusting function and can be adjusted to a desired temperature.

<Second pressing step>
In the second pressing step, the conveyed sheet-like material is sandwiched and pressed between the second pressing roll 5b and the third pressing roll 5c as shown in FIG. In the second pressing step, a transfer mold 6 provided on the surface of the third pressing roll 5c is formed on the sheet-like material. In the present invention, the third pressing roll provided with a transfer mold is also referred to as a shaping roll. The transfer mold provided on the surface of the shaping roll is pressed against the surface of the sheet-like material, and is shaped into the sheet-like material with the surface shape as an inverted mold.

  In the second pressing step, the sheet-like material is pressed again by the second pressing roll and the shaping roll, peeled off from the second pressing roll, and closely adhered to the shaping roll, this time according to the rotation of the shaping roll. Be transported. At that time, when the surface temperature of the sheet-like material is high and the sheet-like material sufficiently adheres to the shaping roll without being pressed by the second pressing roll and the shaping roll, the second pressing roll and the shaping roll The gap may be slightly larger than the thickness of the sheet. The sheet-like material conveyed according to the rotation of the shaping roll is peeled off from the shaping roll, and the shaped resin sheet 1 is obtained.

  The transfer mold 6 is composed of a plurality of concave portions provided on the surface of the shaping roll, and the shape of the concave portion is preferably a reverse type of the cross-sectional shape of the convex portion on the surface of the resulting shaping resin sheet 1. When the cross-sectional shape of the portion is a triangle, it is preferably a V-shaped groove substantially the same as the shape of the triangle.

  When the distance between the apexes of the adjacent concave portions of the shaping roll is the pitch interval (P) and the distance from the circumference of the shaping roll surface to the apex of the concave portion is the groove depth (H), the pitch interval (P) Is preferably 10 μm or more and 10 cm or less, and the groove depth (H) is preferably 1 μm or more and 1 cm or less.

  As a method for producing the transfer mold, the surface of the transfer roll made of stainless steel, steel, or the like is subjected to plating treatment such as chrome plating, copper plating, nickel plating, nickel-phosphorous plating, and then applied to the plated surface. The shape may be processed by performing removal processing using a diamond tool, a metal grindstone, or the like, laser processing, or chemical etching, but is not particularly limited to these methods.

  The surface of the shaping roll may be subjected to plating treatment such as chrome plating, copper plating, nickel plating, nickel-phosphorous plating, etc. at a level that does not impair the accuracy of the surface shape after the transfer mold is formed.

  By shaping the surface shape (transfer mold) of the shaping roll into a sheet-like material in the second pressing step, the desired shaped resin sheet 1 can be produced. The obtained shaped resin sheet 1 is usually further cooled and then cut into single sheets and used for a screen.

  In the production method of the present invention, the first pressing roll is used as the shaping roll, not the third pressing roll, and the sheet-like material extruded from the die is sandwiched between the shaping roll and the second pressing roll and molded. Alternatively, the second pressing roll may be a shaping roll, and the sheet-like material extruded from the die may be sandwiched between the shaping roll and the second pressing roll for shaping.

<Screen>
The screen of the present invention has a light selective layer in which one or a plurality of shaping resin sheets obtained by the above production method are arranged, and if necessary, has a reflective layer and a supporting substrate. Is. As the light selection layer, preferably, the convex portion is formed so as to totally reflect the light beam that travels beyond the set angle, and more preferably, the shaping resin sheet having the convex portion on one surface. Or a pair of shaping resin sheets are arranged so that the shaping surfaces face each other via an air layer, and more preferably a convex portion on one surface Or a pair of shaping resin sheets arranged such that the shaping surfaces face each other via an adhesive or a pressure-sensitive adhesive.
The pressure-sensitive adhesive or adhesive is not particularly limited as long as it can paste the shaping resin sheet. For example, a pressure-sensitive pressure-sensitive adhesive, an active energy ray-curable pressure-sensitive adhesive, and a thermosetting pressure-sensitive adhesive Agents, active energy ray curable adhesives, thermosetting adhesives, and the like.
A schematic diagram of a light selective layer according to an embodiment of the present invention is shown in FIG.

  The air layer 9 means a gap between the molding surfaces of the pair of molding resin sheets 1A and 1B. In the light selection layer according to the embodiment shown in FIG. 1, the lower left slope 9a and the lower right slope 9b Are repeatedly arranged.

  When arranging a pair of shaping resin sheets so that the shaping surfaces face each other, the facing convex portions are preferably point-symmetrical, for example, when the cross-sectional shape is a triangle, the facing triangle is It is preferable that the relation is point-symmetric with the midpoint of one hypotenuse of the triangle as the center of symmetry.

  It is preferable that the outer periphery of the pair of shaping resin sheets is surrounded by a frame member. Since the outer periphery of the screen of the present invention is surrounded by the frame member, the thickness of the air layer between the pair of shaping resin sheets can be easily maintained, and the effect can be easily exhibited.

  The light selection layer 8 in the screen of the present invention has a flat surface 8X on one surface and a flat surface 8Y on the other surface, and the flat surface 8X and the flat surface 8Y are parallel to each other. The refractive index of the resin is generally in the range of 1.3 to 1.7, and the light transmittance is usually around 90%. For example, in the case of a (meth) acrylic resin, the refractive index is about 1.5, and the light transmittance is 92% or more and 93% or less. The light selective layer 8 includes an inclined surface 9a inclined at an angle 2a with respect to the plane 8X and an inclined surface 9b inclined at an angle 2b with respect to the plane 8X, and has an air layer 9 having a certain thickness. The inclination angle 2a of the air layer 9 (that is, the first base angle 2a of the triangular convex portion of the shaping resin sheet) can be set in consideration of the technical matters described below.

  Here, the case where the resin of the shaping resin sheet 1A and the shaping resin sheet 1B constituting the light selection layer 8 of the screen is a resin having a refractive index of 1.5 will be described as an example. In general, when light travels from a medium (resin) having a large refractive index to a medium (air) having a small refractive index, refraction occurs at the interface between the two when the incident angle is small. In this example, since the refractive index of the resin is 1.5 and the refractive index of air is 1, the refractive angle is larger than the incident angle. As the incident angle gradually increases, the refraction angle also increases gradually. When the incident angle exceeds a certain angle, the light does not travel from the resin to the air side, and the light is totally reflected at the interface between the resin and the air layer. In this specification, this angle is referred to as a critical angle and is denoted as θm.

In the case of this example, there is the following relationship between the critical angle θm and air and resin.
sin θm = (refractive index of air) / (refractive index of resin) = 1 / 1.5
Therefore, the critical angle is θm = 41.8 °.

  For example, as shown in FIG. 3, the light selection layer 8 according to an embodiment of the present invention is used as a part of the reflective screen, the plane 8X is the viewer side, the base angle 2a is the upper side, and the base angle 2b is the lower side. When the light selection layer 8 is arranged perpendicular to the ground so as to be on the side, light (light emitted from the projector 10) with a small incident angle (angle formed by light and a perpendicular of the plane 8X) from the viewer side to the plane 8X ) Is refracted on the plane 8X, then travels through the shaping resin sheet 1A, refracts at the interface between the shaping resin sheet 1A and the air layer 9, travels through the air layer 9, and is impregnated with the air layer 9. After being refracted at the interface of the mold resin sheet 1B, it proceeds in the shaping resin sheet 1B, refracts on the plane 8Y, is reflected by the reflective layer 12, and enters the viewer side. Therefore, the viewer 11 can recognize the image shown on the screen.

  On the other hand, when light (for example, sunlight) is incident on the plane 8X at a large incident angle, the light is refracted by the plane 8X and then travels through the shaping resin sheet 1A, at the interface between the shaping resin sheet 1A and the air layer 9. It is totally reflected and does not pass through the air layer 9 and the shaping resin sheet 1B, and the entry into the reflective layer 12 is blocked.

  Also, as shown in FIG. 4, the light selection layer 8 according to an embodiment of the present invention is used as a part of a transmissive screen, the plane 8Y is the viewer side, the plane 8X is the projector side, and the base angle 2a is When the light selection layer 8 is arranged perpendicular to the ground so that the upper side and the base angle 2b are on the lower side, light is incident on the plane 8X from the projector side with a small incident angle (angle formed by the light and the perpendicular of the plane 8X). When (light emitted from the projector 10) is incident, after being refracted by the plane 8X, it proceeds in the shaping resin sheet 1A, refracts at the interface between the air layer 9 and the shaping resin sheet 1B, and then in the shaping resin sheet 1B. After proceeding and refracting on the plane 8Y, it enters the viewer side. Therefore, the viewer 11 can recognize the image shown on the screen. However, light (for example, sunlight) that enters the plane 8X from the projector side with a large incident angle is refracted at the plane 8X, and then travels through the shaping resin sheet 1A and is totally reflected at the interface of the air layer 9. The air layer 9 and the shaping resin sheet 1B do not permeate.

  In this specification, the incident angle of light that is no longer incident on the air layer 9 and the shaping resin sheet 1B from the ground surface to the plane 8X is referred to as a specific angle. The specific angle changes according to the inclination angle 2 a of the air layer 9. When a resin having a refractive index of 1.5 is used as the resin for the shaping resin sheets 1A and 1B constituting the light selection layer 8, when the inclination angle 2a of the air layer 9 is 5 °, the specific angle is 63.9 °. When the inclination angle 2a is 10 °, the specific angle is 52.2 °, when the inclination angle 2a is 20 °, the specific angle is 33.9 °, and when the inclination angle 2a is 28 °, The specific angle is 21.4 °.

For example, when the inclination angle 2a of the air layer 9 is 28 °, the specific angle is 21.4 ° when the refractive index is 1.5. Light incident from above at an angle greater than 21.4 ° and an angle 25 ° from the direction perpendicular to the plane 8X is refracted when incident on the plane 8X, and enters the oblique air layer 9 at an angle of 45 °. . Since this angle is larger than the critical angle at the interface between the shaping resin sheet 1A and the air layer 9, total reflection occurs and light is reflected at this interface. The reflected light is reflected in the shaping resin sheet 1A and does not pass through the air layer 9 and the shaping resin sheet 1B. On the other hand, with respect to light incident at an angle smaller than the specific angle of 21.4 °, the shaping resin is formed at an angle smaller than the critical angle of the interface between the shaping resin sheet 1A and the air layer 9 with respect to the air layer 9. Since it enters the air layer 9 from the sheet 1A, it is refracted without causing total reflection. And reverse refraction occurs when entering the shaping resin sheet 1B from the air layer 9, and if the width of the air layer 9 is small, it is hardly affected by the air layer 9 and permeates in the same manner as normal glass. For this reason, the thickness of the air layer 9 is desirably 0.1 mm or less.
The lower limit of the thickness of the air layer 9 is about 0.01 mm from the viewpoint that the role of the air layer 9 can be exhibited.

  For example, light incident at an angle greater than 22 ° and an angle from a direction perpendicular to the plane 8X undergoes total reflection at the interface between the shaping resin sheet and the air layer. At this time, the totally reflected light travels again through the shaping resin sheet 1A. Further, the light reaching the reflective layer side from the shaping resin sheet 1A undergoes total reflection, and proceeds again in the shaping resin sheet 1A. This light again travels through the shaping resin sheet 1A and then reaches the interface with the air layer 9 to cause total reflection. As a result, it is confirmed that the light eventually proceeds to the lower end portion of the shaping resin sheet, and the light is condensed on the end portion.

  When the light selective layer of the present invention is used as a part of a reflective screen or a transmissive screen, the projector is present at the same height as the screen or at a lower height than the screen, or the projector is more than the screen. When the light exiting the projector at a high height is incident at an angle smaller than a specific angle, the light is not totally reflected at the interface of the air layer but reflected by the reflective layer. Can be recognized. On the other hand, when the projector is at a height higher than the screen and the light emitted from the projector is incident at an angle larger than a specific angle, the viewer totally reflects at the interface of the air layer. , You can not see the image on the screen.

As shown in FIG. 3, the reflective screen may have a reflective layer 12 and a support substrate 13.
Examples of the supporting substrate 13 used for the reflective screen include a glass plate, a metal plate, a wooden board, paper, cloth, and a resin sheet. Among these, a resin sheet is preferable, and examples thereof include the thermoplastic resin exemplified above.
The reflective layer 12 used in the reflective screen is a layer that reflects incident light, and may have a light reflecting material. For example, a layer including metal particles, a layer formed of a metal foil, or the like. Is mentioned. Among these, a layer formed of a metal foil is preferable from the viewpoint of excellent reflectivity. Examples of the metal used as the metal foil include titanium, nickel, copper, silver, zinc, aluminum, and tin. Aluminum or silver is preferable.

  The transmission screen may have a support base 13 as shown in FIG. As the support substrate 13 used for the transmission screen, a transparent material or a translucent material is used, and examples thereof include a glass plate and a transparent resin sheet. Preferably, it is a transparent resin sheet.

  The screen of the present invention can be used by projecting an image with a projector such as a projector or a projector. Therefore, it can provide as an image projection system provided with the screen and projector of this invention.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples.

Example 1
A methacrylic resin (SUMIPEX (registered trademark) EX, manufactured by Sumitomo Chemical Co., Ltd.) is supplied to an extruder having a screw diameter of 65 mm and melt-kneaded at 210 to 260 ° C., and the T-die temperature is passed through the multi-block and the T-die. A continuous resin sheet is produced by extrusion into a sheet at 260 ° C. The extruded continuous resin sheet is sandwiched (pressed) between a first pressing roll, which is a mirror-cooled cooling roll having a surface plated with chromium, and a second pressing roll having a transfer mold on the surface, and the rotation of each pressing roll. The transfer mold is transferred onto the surface of the continuous resin sheet while being sequentially conveyed. Thereafter, the continuous resin sheet is conveyed in a state of being in close contact with the second pressing roll, and then sandwiched (pressed) between the second pressing roll and a third pressing roll which is a mirror-finished roll having a surface plated with chrome. Then, it is sequentially conveyed by the rotation of each pressing roll, and thereafter taken up by a take-up roll, and a molded resin sheet having a convex portion on one surface is obtained. The obtained molded resin sheet has a base angle 2a of 25 °, a base angle 2b of 45 °, a height of the convex portions of 80 μm, and a pitch of 250 μm. Using the obtained shaped resin sheet as a light selective layer, applying a pressure-sensitive acrylic pressure-sensitive adhesive (NSS, Shin Tak Kasei Co., Ltd.) to the light selective layer, and further laminating an aluminum foil as a reflective layer, A reflective screen is obtained. Moreover, using the obtained shaped resin sheet as a light selection layer, applying the pressure-sensitive acrylic adhesive described above to the light selection layer, and further, an acrylic plate (E000 3 mmt, manufactured by Sumitomo Chemical Co., Ltd.) as a support substrate ) To obtain a transmission screen.

(Comparative Example 1)
A methacrylic resin (Sumipex (registered trademark) EX, manufactured by Sumitomo Chemical Co., Ltd.) is supplied to an extruder having a screw diameter of 65 mm, melt-kneaded at 210 to 260 ° C., and a T-die temperature of 260 through a multi-block and a T-die. A continuous resin sheet is produced by extruding into a sheet at a temperature of ° C. The extruded continuous resin sheet is sandwiched (pressed) between a first pressing roll, which is a mirror-surface cooling roll whose surface is chrome-plated, and a second pressing roll, which is a metal mirror-surface cooling roll whose surface is chrome-plated. Then, it is sequentially conveyed by the rotation of each pressing roll. Next, sandwiched (pressed) with a second pressing roll and a third pressing roll which is a mirror-cooled roll with chrome plating on the surface, sequentially conveyed by the rotation of each pressing roll, and then taken up with a take-up roll, A resin sheet that does not retain its shape is obtained. Using the obtained resin sheet as a light selective layer, a pressure-sensitive acrylic pressure-sensitive adhesive (NSS, Shin-Tac Kasei Co., Ltd.) is applied to the light selective layer, and an aluminum foil as a reflective layer is further laminated. Get the screen. Further, the obtained molded resin sheet is used as a light selection layer, the above-mentioned pressure-sensitive acrylic pressure-sensitive adhesive is applied to the light selection layer, and an acrylic plate as a supporting substrate is further laminated to obtain a reflective screen. .

(Projector projection test (reflection type))
An image is projected on the reflective screen produced in Example 1 or Comparative Example 1 by a projector from the viewer side under sunlight or indoor lighting. When the reflective screen of Example 1 is used, glare due to sunlight or reflected light from indoor lighting is suppressed, and an image reflected on the screen can be recognized. When the reflective screen of Comparative Example 1 is used, it is difficult to recognize an image reflected on the screen because of glare caused by sunlight or reflected light from indoor lighting.

(Projector projection test (transmission type))
An image is projected by a projector from the opposite side to the viewer under indoor lighting on the transmissive screen produced in Example 1 or Comparative Example 1. When the transmissive screen of Example 1 is used, glare due to transmitted light of indoor lighting is suppressed, and an image reflected on the screen can be recognized. When the transmissive screen of Comparative Example 1 is used, it is difficult to recognize an image reflected on the screen due to the glare caused by the transmitted light of the indoor lighting.

  The evaluation results are summarized in Table 1 below. The one with good visibility is marked with ◯, and the one with poor visibility is marked with x.

DESCRIPTION OF SYMBOLS 1 Molding resin sheet 2 Bottom angle 3 Hopper 4 Die 5 Roll 6 Shaping roll 7 Extruder 8 Light selective layer of screen 9 Air layer 10 Projector
11 viewer 12 reflective layer 13 support substrate

Claims (6)

  A screen having a light selection layer in which one or a plurality of shaping resin sheets having convex portions on one surface are arranged.   The screen according to claim 1, wherein a height of the convex portion is 1 μm or more and 100 μm or less, and a pitch interval is 10 μm or more and 1 mm or less.   The screen according to claim 1, wherein the convex portion is a triangular convex portion whose cross-sectional shape is a triangle.   When a straight line connecting both ends of the bottom of the triangular convex portion is a triangle base, one base angle of the triangle is more than 20 ° and 45 ° or less, and the other base angle is more than 0 ° and less than 89 °. The screen according to claim 3.   The screen according to any one of claims 1 to 4, further comprising a reflective layer.   An image projection system comprising: the screen according to claim 1; and a projector that projects an image on the screen.

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