JP2005241687A - Lens sheet and transmissive screen - Google Patents

Abstract

An object of the present invention is to provide a lens sheet and a transmissive screen in which at least a lens layer and a diffusion plate can be maintained in a stable close contact state with a plurality of sheet members. .
In a transmission screen combining at least a lens sheet in which a lens layer and a diffusion layer are laminated and at least a Fresnel lens sheet, the ratio of the long side to the short side of the lens sheet corresponds to 16: 9 or 4 A rectangular shape equivalent to 3 and restrains the sheet from the upper limit and the lower limit that the relationship between the length in the short side direction (the vertical direction of the image) and the warpage size satisfies a specific range. In a state where it is not bent, it is formed into a curved shape in the short side direction, and when combined with the Fresnel lens sheet or the like, warpage is imparted so that the center part of the lens sheet is convex toward the Fresnel lens sheet side. And a transmissive screen combining the lens sheets.
[Selection] Figure 1

Description

  The present invention relates to a transmissive screen for a rear projection type image display device in which an image from a projection device is projected from the back of the screen, and uses an image panel having a large number of pixels such as a liquid crystal panel and a DMD. It is a transmission type screen suitably used for a rear projection type video display device provided with a single lens system projection device.

  2. Description of the Related Art In recent years, development of a rear projection type video display device having a single lens system projection device using an image panel having a large number of pixels such as a liquid crystal panel and a DMD has been actively developed. In this projection device, the image panel such as a liquid crystal panel or DMD does not self-emit, but the light that is modulated and transmitted by the image panel out of the light emitted from the light source arranged on the back side of the image panel passes through the magnifying lens. Projected toward the screen. In general, a transmissive screen used in a conventional rear projection type image display device is configured by a combination of a Fresnel lens sheet and a lenticular lens sheet. In the lenticular lens sheet, an external light absorption layer, a light diffusion layer, and the like are formed, and an antireflection layer may be formed on the outermost surface on the viewer side. In addition to the Fresnel lens sheet and the lenticular lens sheet, a front plate may be disposed on the outermost surface on the viewer side. A divergent light beam from an image source composed of a light source, an image panel, etc. is projected from one surface of a Fresnel lens sheet having a Fresnel lens formed on the surface of a transparent resin plate, and this image light beam is collimated by a Fresnel lens sheet. Or it can be changed to a convergent beam. The parallel or convergent light beam that has passed through the Fresnel lens sheet is transmitted through a lenticular lens sheet formed so that the convex cylindrical lens repeats in the horizontal direction, and the horizontal viewing angle on the observation side is expanded by the lenticular lens sheet and projected. A picture is created. The front plate fulfills functions such as protection of the lenticular lens sheet.

  In a transmissive screen in which a plurality of lens sheets are stacked in the optical axis direction, if both lens sheets are not sufficiently adhered and there is a gap, the screen is distorted in appearance and a double image is generated. Various adverse effects such as deterioration in image quality, undesired coloration in the image, and inability of the screen to exhibit optical characteristics according to the design are caused. In particular, the influence due to poor adhesion at the center of the lens sheet is great. The phenomenon in which gaps that cause such harmful effects are generated is called “floating”.

  In order to prevent such a gap from occurring, in a transmission screen configured by combining two lens sheets, warping (curving) is applied to at least one lens sheet. There are various types of warping, one lens sheet is convex on the other lens sheet side, both lens sheets are convex on the other lens sheet side, both lenses There is a form in which the sheet is curved in the same direction, and the lens sheet that is convex toward the other lens sheet is largely warped. However, even when warping is applied in various forms, a gap may be generated with a change in conditions over time / environment, and it is difficult to completely eliminate the floating.

Depending on the size, material, mechanical properties (rigidity, etc.) and chemical properties (expansion rate, etc.) screen configuration and various environmental conditions (temperature, humidity), etc., the degree of floatation varies. Verification of experimental data is the only confirmation means for setting conditions for reducing floating. In such a technical field, the curved shape does not change with time, and a plurality of sheet members can maintain a stable close contact state, and a large amount of warpage is imparted to the lens sheet constituting the transmission screen. A simple method for obtaining the relationship between the two has been desired.

  The present invention has been made in view of the above problems, and a lens sheet in which at least a lens layer and a diffusion plate that can maintain a stable adhesion state with a plurality of sheet members are laminated, and the lens sheet and at least Fresnel. An object of the present invention is to provide a transmissive screen in which a lens sheet is combined.

In order to achieve the above object, that is, the invention according to claim 1,
In a lens sheet that is combined with a Fresnel lens sheet to form a transmissive screen, a lens is formed on at least one side,
The lens sheet has a rectangular shape in which the ratio of the long side to the short side is 16: 9, the length in the short side direction (vertical direction of the image) is x (mm), and the warp of the lens sheet in the short side direction Where y is the upper limit of the xy region surrounded by a straight line represented by the following relational expressions (1) to (4). The lens sheet has a warp amount in the short side direction between the lower limit and the lower limit.

x = 500 (mm) (1)
x = 800 (mm) (2)
y = 5.0 (mm) (3)
y = 0.043x + 7.2 (mm) (4)
The invention according to claim 2
In a lens sheet that is combined with a Fresnel lens sheet to form a transmissive screen, a lens is formed on at least one side,
The lens sheet has a rectangular shape in which the ratio of the long side to the short side is 4 to 3, the length in the short side direction (vertical direction of the image) is x (mm), and the warp of the lens sheet in the short side direction Where y is the upper limit of the xy region surrounded by a straight line represented by the following relational expressions (5) to (8). The lens sheet has a warp amount in the short side direction between the lower limit and the lower limit.

x = 600 (mm) (5)
x = 900 (mm) (6)
y = 5.0 (mm) (7)
y = 0.064x-12.2 (mm) (8)
The invention according to claim 3
3. The lens sheet according to claim 1, wherein a central portion of the lens sheet is provided with a warp that is convex toward the Fresnel lens sheet side. 4.

The invention according to claim 4
The lens sheet according to claim 1, wherein a diffusion layer is laminated on the lens sheet.

The invention according to claim 5
The lens sheet includes a lenticular lens in which convex cylindrical lens groups are arranged in parallel using refraction or total reflection, a lens sheet having a prism array, and a lens sheet having a microlens structure in which unit lenses are two-dimensionally arranged. The lens sheet according to claim 1, wherein the lens sheet is any one.

The invention according to claim 6
A transmissive screen comprising a combination of the lens sheet according to claim 1 and a Fresnel lens sheet so that a center portion of the lens sheet has a warp convex toward the Fresnel lens sheet. .

  According to the present invention, it is possible to obtain a transmissive screen that is less likely to be deformed due to moisture absorption and desorption and that does not have a risk of image quality deterioration due to changes in temperature and humidity. The amount of warpage does not change over time, and even when a plurality of lens sheets are used in combination for a long period of time, gaps are generated between the sheet members, and floating occurs. It becomes too strong and does not rub and scratch.

  A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic vertical sectional view of an example of the transmission screen of the present invention before assembly. As shown in FIG. 1, it is a transmissive screen 1 comprising a lens sheet 20 formed by laminating a Fresnel lens sheet 10, a warped lens layer, and a diffusion plate (both not shown). The transmission screen of the present invention is not limited to the above-described configuration, and may be a configuration in which, for example, a front plate that functions to protect the screen is provided on the observation side.

  The lens sheet having warpage in the present invention is a Fresnel lens sheet having a warp size of 5 mm or less even if the ratio of the long side to the short side is a rectangular shape corresponding to 16: 9 or 4: 3. It has been empirically found that when the transmission screen is combined with the above, the image quality is deteriorated due to “floating” due to changes in moisture absorption / release and temperature / humidity.

  The lens sheet 20 having warpage in the present invention has a rectangular shape with a ratio of long side to short side of 16: 9, and the length in the short side direction (vertical direction of the image) is x as shown in FIG. (Mm) When the magnitude of the curvature of the curved lens sheet in the short side direction is expressed by y (mm), the relationship between the length in the short side direction and the magnitude of the warp is as follows, as shown in FIG. In the xy coordinates, the shape of the warp between the upper limit and the lower limit satisfying the range surrounded by the straight line of (1) to (4) is formed into a curved shape in the short side direction without restraining the sheet, and the Fresnel When combined with a lens sheet, the center of the lens sheet is warped so as to be convex toward the Fresnel lens sheet.

x = 500 (mm) (1)
x = 800 (mm) (2)
y = 5.0 (mm) (3)
y = 0.043x + 7.2 (mm) (4)
For example, in a rectangular lens sheet having a ratio of the long side to the short side of 16: 9, a lens sheet having a length x of 700 mm in the short side direction is combined with the Fresnel lens sheet and deformed by moisture absorption / release. There is little risk of image quality degradation due to changes in temperature and humidity, the amount of warpage (warpage size) does not change over time, and multiple lens sheets can be used in combination for a long period of time. When a transmissive screen is produced in which a gap is generated between the sheet members and the float does not occur, or on the contrary, the adhesion between the lens sheets becomes too strong to cause rubbing scratches. The amount of warp to be added to the length in the short side direction of 700 mm of the x axis is obtained by calculating the warp amount represented by the intersection with the y axis indicating the upper limit and the lower limit of the range surrounded by dots. Since the upper limit is 37.3 mm and the lower limit is 5 mm, the warp amount with respect to the length in the short side direction of 700 mm is given to a lens sheet having a length in the short side direction equivalent to 16: 9 in the length of 700 mm. The warping amount to be added may be a warping amount in the range of 5 to 37.3 mm.

  The lens sheet 20 according to the present invention has a rectangular shape with a ratio of the long side to the short side of 4 to 3, and the length in the short side direction (vertical direction of the image) is x as shown in FIG. (Mm) When the magnitude of the curvature of the curved lens sheet in the short side direction is represented by y (mm), the relationship between the length in the short side direction and the magnitude of the warp is as follows, as shown in FIG. The Fresnel is formed into a curved shape in a short side direction without restraining the sheet to a warp size between an upper limit and a lower limit satisfying a range surrounded by a straight line of (5) to (8) in the xy coordinates of When combined with a lens sheet, the warp is characterized in that the center of the lens sheet is warped so as to be convex toward the Fresnel lens sheet.

x = 600 (mm) (5)
x = 900 (mm) (6)
y = 5.0 (mm) (7)
y = 0.064x-12.2 (mm) (8)
For example, in a rectangular lens sheet having a ratio of the long side to the short side of 4 to 3, a lens sheet having a length x of 800 mm in the short side direction is combined with the Fresnel lens sheet and deformed by moisture absorption and desorption. There is little risk of image quality degradation due to changes in temperature and humidity, the amount of warpage (warpage size) does not change over time, and multiple lens sheets can be used in combination for a long period of time. In the case where the product is a transmissive screen in which a gap is generated between the sheet members and the float does not occur, or on the contrary, the adhesion between the lens sheets becomes too strong to cause rubbing scratches, from FIG. The amount of warp to be added to the length of the x-axis in the short side direction of 800 mm is obtained by calculating the amount of warpage represented by the intersection with the y-axis indicating the upper and lower limits of the range surrounded by dots. Since the upper limit is 39 mm and the lower limit is 5 mm, the warp amount with respect to the length in the short side direction of 800 mm is the warp amount imparted to the lens sheet having the long side to short side ratio of 4 to 3 and the short side length of 800 mm. May be added with a warping amount in the range of 5 to 39 mm.

  The relationship between the length in the short side direction (vertical direction of the image) and the warp size satisfies the following xy coordinate range and the warp size between the upper limit and the lower limit, with the sheet being not restrained, the short side It is possible to easily obtain a suitable amount of warping for lens sheets of various sizes with a curved curvature in the direction, and the curved shape does not change over time, and a plurality of sheet members are in a stable contact state It is possible to impart a warp that can maintain the above.

  The lens sheet used in the present invention is a lens sheet in which at least a lens layer and a diffusion layer are laminated, and the lens shape is a lenticular lens, a prism lens, or two-dimensional array using refraction or total reflection. Or a combination of these microlenses.

  FIG. 5 is a horizontal sectional view showing a lens sheet according to an embodiment of the present invention. As the lens sheet used in the present invention, for example, a lens sheet 20 (1) having a configuration shown in FIG. 5 is used. In FIG. 5, an image light source is arranged on the left side of the drawing, and an observer is located on the right side of the drawing. A convex cylindrical lens portion a made of a cured ionizing radiation curable resin is formed on a support of a transparent substrate b, and a black light-shielding layer c corresponding to a non-light-collecting portion of the cylindrical lens portion is formed. It is a lens sheet having a configuration in which a light diffusion plate d in which a light diffusion agent d1 is mixed and dispersed is disposed on the surface of the light shielding layer c via an adhesive layer e.

A convex cylindrical lens portion a made of a cured product of ionizing radiation curable resin applies an ionizing radiation curable resin composition to the molding surface of an embossing roll mold, and supplies a transparent substrate b to the embossing roll mold. Irradiating ionizing radiation through the transparent substrate b to cure the resin, and at the same time, polymerize the cylindrical lens a which is a resin molding to the transparent substrate b, or cure the ionizing radiation to the transparent substrate. The resin composition is applied, supplied to an embossing roll mold, irradiated with ionizing radiation through the transparent substrate b, and the resin is cured, and at the same time, the cylindrical lens a which is a resin molded product is transparent. Although it shape | molds by the method of superposing | polymerizing and adhering to the material b etc., it is not limited to these methods in particular. The shape of the convex cylindrical lens a may be circular or aspherical, and the shape is not particularly limited.

  The transparent substrate b is a transparent support for supporting the cylindrical lens portion, and the transparent substrate is not particularly limited, but polyethylene terephthalate (PET), polycarbonate (PC) film substrate is used. preferable.

  The black light-shielding layer c corresponding to the non-light-condensing part of the cylindrical lens part a has adhesiveness on the flat surface of the transparent base material b on the opposite side of the cylindrical lens part a, and the adhesiveness is obtained by irradiation with ultraviolet rays. An ultraviolet curable resin layer having the characteristic of disappearing is applied or laminated with a film-like ultraviolet curable resin. Next, a black powder toner is obtained by using the viscosity of the resin in the uncured portion of the ultraviolet curable resin layer other than the portion that is irradiated with ultraviolet rays through the cylindrical lens a and condensed and cured by the lens action. Is attached only to the uncured portion to form the black light shielding layer c. Examples of the black powder toner include black pigments, pigments, carbon, metal salts, or black-colored acrylic resins, organic silicone resins, polystyrene, urea resins, and formaldehyde condensates, but are not particularly limited. . If necessary, two or more kinds of black powder toners may be used in combination.

  Alternatively, a black colored layer is formed by utilizing the viscosity of the resin in the uncured portion of the ultraviolet curable resin layer other than the portion that is irradiated with ultraviolet rays through the cylindrical lens a and condensed and cured by the lens action. By superimposing the transfer sheet on the colored layer side, using the viscosity of the resin in the uncured part, attaching the colored layer only to the uncured part, and then peeling the colored layer in the cured part from the lens sheet The black light shielding layer c may be formed. The transfer sheet is not particularly limited to the material and configuration of the transfer sheet as long as it is a transfer sheet having a black colored layer, and a general-purpose transfer sheet can be used.

  FIG. 6 is a horizontal sectional view showing another lens sheet according to the embodiment of the present invention. As another example of the lens sheet used in the present invention, a lens sheet 20 (2) having a configuration shown in FIG. 6 is used. In FIG. 6, an image light source is arranged on the left side of the drawing, and an observer is located on the right side of the drawing. This lens sheet 20 (2) is arranged by adhering a light diffusing plate j in which a light diffusing agent j 1 is mixed and dispersed through an adhesive layer i to a unit lens g formed on a transparent substrate h. ing. Further, the triangular section f sandwiched between the oblique sides of the adjacent unit lenses g, g is filled with a material having a refractive index N2 lower than the refractive index N1 of the unit lens g. In the following description, the portion filled with the low refractive index material is referred to as “low refractive index portion f”. Further, the unit lens g is referred to as a “high refractive index portion g” as necessary.

  The ratio between the refractive index N1 of the high refractive index portion g and the refractive index N2 of the low refractive index portion f is set within a predetermined range in order to obtain the optical characteristics of the light diffusion sheet S. Further, the angle formed by the hypotenuse where the low refractive index portion f and the high refractive index portion g are in contact with the normal line of the light exit surface (parallel to the perpendicular incident light with respect to the light diffusion sheet) is formed at a predetermined angle θ. ing.

  The high refractive index portion g is usually made of a material such as epoxy acrylate having ionizing radiation curability. The low refractive index portion f is formed of a material having a refractive index lower than that of a transparent resin such as silica. The low refractive index portion f is colored to a predetermined concentration with a pigment such as carbon or a predetermined dye. Moreover, the light diffusing plate j and the transparent base material h are comprised with the material which has substantially the same refractive index as the high refractive index part g.

The high refractive index portion g that functions as a lens portion of the lens sheet 20 (2) and the low refractive index portion f that functions as a light shielding portion are manufactured by, for example, the following manufacturing method. On the surface of the mold roll that rotates at a predetermined speed, a female mold corresponding to a triangular section that forms the low refractive index portion f is engraved. A low refractive index resin heated to a predetermined temperature is supplied from a resin feeder onto a mold roll and embedded in a triangular recess. After surplus resin is scraped off with a doctor blade, ionizing radiation is irradiated onto the roll surface with an ionizing radiation irradiator to cure the low refractive index resin. Next, a transparent resin is supplied from the feeder over almost the entire length of the roll width to form a transparent resin layer on the surface of the mold roll. Furthermore, after forming a transparent support film layer on the upper surface by unwinding the base film from the supply roll, the transparent resin is cured by irradiating ionizing radiation again with an ionizing radiation irradiator. And the low-refractive-index part f of the cross-sectional shape triangle currently formed in the surface recessed part of the type | mold roll peels from the roll surface. At this point, the transparent resin layer is formed on the transparent support film, and the low refractive index resin is formed in a cross-sectional triangle on the upper surface of the transparent resin layer.

  A soft high refractive index resin is supplied to the surface of the intermediate product obtained as described above, which is formed in a triangular cross section, and pressed between the rolls. The soft high refractive index resin is pressed into the valley of the triangular cross section formed by the low refractive index resin without any gap. Further, the surface is irradiated with ionizing radiation with an ionizing radiation irradiator to cure the high refractive index resin. The cured high refractive index resin is peeled off. At this time, a high refractive index resin layer having a trapezoidal cross section is formed on the upper surface of the low refractive index resin having a triangular cross section.

  The light diffusing plates d and j used in the present invention form an image of the projection light and eliminate the see-through phenomenon of the light source so that the brightness of the screen becomes uniform and even when observed from an oblique direction. Any method can be used as long as it has an effect of diffusing projection light so that a certain level of bright images can be observed.

For example, a resin plate in which a diffusing agent is mixed and dispersed in a resin having excellent translucency, such as a polyester resin, a styrene resin, an acrylic resin, an acrylic-styrene copolymer resin, a polycarbonate resin, and a vinyl chloride resin. As the light diffusing agent, it is preferable to add mainly spherical glass beads or resin beads mainly composed of SiO ₂ having a particle diameter of 5 to 100 μm as a main component. Further, if necessary, inorganic fine powder such as powdered glass, finely pulverized glass fiber, titanium oxide, calcium carbonate, silicon dioxide (silica), aluminum oxide, or crosslinked polymer resin fine particles can be added.

  Furthermore, what is demonstrated below can also be used as a light-diffusion board which can control light diffusibility easily and has the surface excellent in the external appearance property and the adhesiveness with another base material.

  FIG. 7 is a cross-sectional view showing another example of the light diffusing plate used in the present invention. As a light diffusing plate, the intermediate layer k is made of a resin mixed with a light diffusing agent k1, and the outer layer 1 and m of the front and back surfaces are molded by coextrusion made of a transparent resin. The layer 40 is provided, and the matting agent 41 is mixed in the hard coat layer.

  The synthetic resin that forms the intermediate layer k of the three-layered resin plate used in the present invention and the outer layers 1 and m on the front and back sides can be co-extruded and has excellent translucency. Although not particularly limited, polyester resin, styrene resin, acrylic resin, acrylic-styrene copolymer resin, polycarbonate resin, vinyl chloride resin, and the like can be given.

The light diffusing agent k1 mixed in the intermediate layer k of the three-layered resin plate used in the present invention is mainly composed of spherical glass beads or resin beads mainly composed of SiO ₂ having a particle diameter of 5 to 100 μm. It is desirable to add. Further, if necessary, inorganic fine powder such as powdered glass, finely pulverized glass fiber, titanium oxide, calcium carbonate, silicon dioxide (silica), aluminum oxide, or crosslinked polymer resin fine particles can be added.

  The hard coat layer 40 used in the present invention is formed from an ultraviolet curable paint. UV curable coatings are generally composed mainly of polymers, oligomers, monomers, etc. that have radically polymerizable double bonds or epoxy groups in their structure as film-forming components. Contains sensitizers and sensitizers. What is preferable for the present invention is that the film-forming component uses a polyfunctional (meth) acrylate-based ultraviolet curable coating having an acrylate functional group, so that surface hardness, transparency, abrasion resistance, scratch resistance, etc. It is possible to form an excellent hard coat layer.

  The method of forming a hard coat layer in the present invention, that is, a method of applying an ultraviolet curable paint to one side of a resin plate 30 having a three-layer structure includes, for example, blade coating, rod coating, knife coating, reverse roll coating, spray coating, Although it is applied by any application method such as offset gravure coating, gravure coating, gravure reverse coating, reverse roll coating, offset gravure coating method, etc. excellent in accuracy of application thickness, smoothness of application surface, etc. are particularly suitable. . Moreover, it can also form by transfer using the transfer sheet which used the hard-coat layer as the transfer layer.

  As the matting agent 41 mixed in the hard coat layer 40, silica, titanium oxide, calcium carbonate, ruthenium hydroxide, acrylic resin, organic silicone resin, polystyrene, urea resin, formaldehyde condensate, or the like can be used. One or more of these matting agents may be selected, and although not particularly limited, silica, titanium oxide and the like are preferable. The particle size may be appropriately selected according to the optical performance required for the light diffusing plate.

  Examples of the adhesive constituting the adhesive layer for bonding the light diffusion plates d and j include a pressure-sensitive adhesive, a thermosetting adhesive, and an ultraviolet curable adhesive. It is not particularly limited as long as it has excellent transparency.

  For example, the lens sheet 20 (1) obtained by laminating a lens layer and a light diffusing plate is obtained by arranging a Fresnel lens on the image light source side and a lens sheet on the observation side as shown in FIG. Transmission through a rear projection type video display device in which the image from the projection device is projected from the rear surface provided with a single lens projection device using an image panel having a large number of pixels such as a liquid crystal panel of a screen, DMD, etc. It is suitably used as a mold screen.

  As a method for imparting warp to the lens sheets 20 (1) and 20 (2) formed by laminating the lens layer and the light diffusing plate exemplified above, for example, as shown in FIG. The lens sheet 20 [1 (for example, the lens sheet 20 (1) shown in FIG. 5)] is placed and conveyed on the belt 60 so that the lens portion 20 (1) is on the lower surface, and the cooling roll 50 is lowered [ Refer to FIG. 9 (11-1)], pressurizing and quenching the lens sheet in the heat-softened state via the cooling roll 50 [see FIG. 9 (11-2)]. A curved warp can be imparted by the curvature of the cooling roll. At this time, by using the belt 60 to convey the workpiece, the lens shape of the lens sheet contacting the belt surface 60 is not deformed or scratched without being overloaded except for warping the workpiece. There is nothing to do. After the workpiece is warped, the cooling roll is raised [see FIG. 9 (11-3)] and the workpiece is unloaded.

  The lens sheet 20 provided with the warp by the above method is arranged as shown in FIG. 8 so that the center part of the lens sheet 20 is convex toward the Fresnel lens sheet in combination with the Fresnel lens 10. The transmissive screen shown in FIG. 10 can be configured by superimposing and fixing them together by fixing them with a fixing tool 70 at the periphery.

  Further, as shown in FIG. 11, a front plate 80 that performs functions such as protection of a transmission screen can be disposed on the outermost surface on the observation side as required.

  Examples of the present invention will be specifically described below.

  As a lens sheet having the structure shown in FIG. 5, a convex cylindrical lens a having a lens height of 37 μm made of a cured ionizing radiation curable resin is placed on a support of a polyethylene terephthalate (PET) transparent base material b having a thickness of 75 μm. Then, a black light-shielding layer c having a thickness of 21 μm corresponding to the non-condensing portion of the cylindrical lens a was formed in a stripe shape.

  Also, a separately prepared light diffusion plate d having a thickness of 1.85 mm was prepared, and the light diffusion plate d was bonded to the surface of the black light-shielding layer c via a pressure-sensitive adhesive layer e having a thickness of 40 μm. A rectangular lens sheet having a ratio of the long side to the short side of the configuration corresponding to 16: 9 was prepared.

  The relationship between the length x in the short side direction and the warp y shown in FIG. 3 is as shown in (1) to (4) on the lens sheets having the short side lengths of the various samples of the present invention. The warpage between the upper limit and the lower limit satisfying the xy region surrounded by the straight line is curved in the short side direction without restraining the sheet, and the warp is formed by the warp applying method shown in FIG. A lens sheet with a short side warp was created.

  On the other hand, in order to compare the performance with the samples 1 to 10 of the present invention obtained above, the relationship between the length x in the short side direction and the warp y shown in FIG. 3 is a straight line of (1) to (4). Comparative samples 1 to 10 to which a warp that does not satisfy the enclosed xy region were provided were prepared.

  Combine the lens sheet having warpage obtained above and a predetermined Fresnel lens, and use a predetermined fixing tool at the periphery to overlap the lens sheet so that the center of the lens sheet is convex toward the Fresnel lens sheet. The transmissive screen was made to adhere by fixing. The transmissive screen was mounted on a projection television as a rear projection image display device, and a practical test was conducted. The results are shown in Table 1.

表１には、各サンプルについて短辺反り量、セット装着時の短辺反り量、セット直後および温湿度試験後のスクリーンの状態を示した。○は「浮き」無し、△はやや「浮き」有り（但し、実用上問題のないレベル）、×は「浮き」有り（実用上問題有り）の３段階評価したものである。

Table 1 shows the short side warpage amount, the short side warpage amount when the set was mounted, the state of the screen immediately after the setting and after the temperature and humidity test for each sample. A circle is evaluated in three stages: “no float”, Δ slightly “float” (however, there is no practical problem), and “x” is “float” (practical problem).

  Even in the state after the high-temperature and high-humidity (40 ° C., 95%) test, in the samples 1 to 10 of the present invention that were determined to be OK levels as practical products, 500 (mm) ≦ x (mm) ≦ 800 (mm) The condition of 5 (mm) <y (mm) ≦ 0.043x + 7.2 (mm) is satisfied within the range, and Comparative Samples 1 to 10 are outside the range of the condition. As a result, the contact state of the overlapping lens sheets is stably maintained by changing the temperature and humidity of the environment in which the projection TV using the lens sheet of the present invention (samples 1 to 10 of the present invention) is installed, The desired optical characteristics were obtained without any appearance distortion on the transmission screen, no double image, no deterioration of the resolution of the image, no coloration, and the like.

In the same manner as in Example 1, a rectangular lens sheet having a ratio of the long side to the short side of 4 to 3 was prepared. The relationship between the length x in the short side direction and the warp y shown in FIG. 4 is (5) to (8) on the lens sheets having the short side lengths of the various samples of the present invention of Samples 11 to 18 having different screen sizes.
9), the warp between the upper limit and the lower limit satisfying the xy region surrounded by the straight line is curved in the short side direction without restraining the sheet, and the warp is applied by the warp applying method shown in FIG. The lens sheet which shape | molded and gave the short side curvature was created.

  On the other hand, in order to compare the performance with the samples 11 to 18 of the present invention obtained above, the relationship between the length x in the short side direction and the warp y shown in FIG. 4 is a straight line of (5) to (8). Comparative samples 11 to 18 having warpage not filling the enclosed xy region were created.

  Combine the lens sheet having warpage obtained above and a predetermined Fresnel lens, and use a predetermined fixing tool at the periphery to overlap the lens sheet so that the center of the lens sheet is convex toward the Fresnel lens sheet. The transmissive screen was made to adhere by fixing. The transmissive screen was mounted on a projection television as a rear projection image display device, and a practical test was conducted. The results are shown in Table 2.

  Combine the lens sheet having warpage obtained above and a predetermined Fresnel lens, and use a predetermined fixing tool at the periphery to overlap the lens sheet so that the center of the lens sheet is convex toward the Fresnel lens sheet. The transmissive screen was made to adhere by fixing. The transmissive screen was mounted on a projection television as a rear projection type video display device, and a practical test was conducted in the same manner as in Example 1. The results are shown in Table 2.

表２には、各サンプルについて短辺反り量、セット装着時の短辺反り量、セット直後および温湿度試験後のスクリーンの状態を示した。○は「浮き」無し、△はやや「浮き」有り（但し、実用上問題のないレベル）、×は「浮き」有り（実用上問題有り）の３段階評価したものである。

Table 2 shows the short side warpage amount, the short side warpage amount when the set is mounted, the state of the screen immediately after the setting and after the temperature and humidity test for each sample. A circle is evaluated in three stages: “no float”, Δ slightly “float” (however, there is no practical problem), and “x” is “float” (practical problem).

  Even in the state after the high-temperature and high-humidity (40 ° C., 95%) test, in the samples 11 to 18 of the present invention that were determined to be OK levels as practical products, 600 (mm) ≦ x (mm) ≦ 900 (mm) The condition of 5 (mm) <y (mm) ≦ 0.064x-12.2 (mm) is satisfied within the range, and Comparative Samples 11 to 18 are outside the range of the above condition. As a result, as in Example 1, the contact state of the overlapping lens sheets is stabilized by changing the temperature and humidity of the environment in which the projection TV using the lens sheets of the present invention (samples 11 to 18 of the present invention) is installed. Thus, the transmissive screen is not distorted in appearance, the double image is not generated, the resolution of the image is not deteriorated, the coloring is not generated, and the desired optical characteristics are obtained. .

  It is suitably used as a transmissive screen of a rear projection type video display device provided with a single lens system projection device using an image panel having a large number of pixels such as a liquid crystal panel and DMD.

It is a general | schematic vertical sectional view which shows the thing before an assembly of an example of the transmission type screen of this invention. FIG. 3 is an explanatory diagram for explaining the length of a lens sheet of the present invention in the short side direction (vertical direction of an image) as x (mm) and the amount of warpage of the curved lens sheet in the short side direction as y (mm). is there. In the rectangular lens sheet having a ratio of the long side to the short side of 16: 9 according to the present invention, the length in the short side direction (vertical direction of the image) is x (mm), and the curved lens in the short side direction It is a figure which shows the appropriate range of the magnitude | size of the curvature provided with respect to the length of a short side direction, when the magnitude | size of the curvature of a sheet | seat is represented by y (mm). In the rectangular lens sheet having a ratio of the long side to the short side of 4 to 3 according to the present invention, the length in the short side direction (vertical direction of the image) is x (mm), and the curved lens in the short side direction It is a figure which shows the appropriate range of the magnitude | size of the curvature provided with respect to the length of a short side direction, when the magnitude | size of the curvature of a sheet | seat is represented by y (mm). It is a horizontal sectional view showing an example of a lens sheet before giving warp in the present invention. It is a horizontal sectional view showing other examples of a lens sheet before giving warp in the present invention. It is sectional drawing which shows an example of a structure of the diffuser plate used in this invention. It is a perspective view which shows an example of the transmission type screen which combined the lens sheet and Fresnel lens of this invention. It is explanatory drawing explaining an example of the method of providing curvature to the lens sheet in this invention. Vertical sectional view showing an example of a transmission type screen in which the warped lens sheet of the present invention is adhered by being overlapped and fixed at the peripheral part so that the center part of the lens sheet is convex toward the Fresnel lens sheet side It is. The vertical which shows the other example of the transmissive | pervious type screen which overlap | superposes and adhere | attaches both by fixing so that the center part of the lens sheet | seat which provided the curvature of this invention may become convex toward the Fresnel lens sheet side, and a peripheral part. It is sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transmission type screen 10 ... Fresnel lens sheet 20, 20 (1), 20 (2) ... Lens sheet 20n, 20 (1) n ... Lens opposite side flat surface 20o, 20 (1 ) O ... lens surface 30 ... co-extruded three-layer resin plate 40 ... hard coat layer 41 ... mat agent 50 ... cooling roll 60 ... transport belt 70 ... fixture 80 ... Front plate a ... Cylindrical lens layer b, h ... Transparent base material layer c ... Light shielding layer d, j ... Light diffusion plate d1, j1, k1 ... Light diffusion agent e, i: Adhesive layer f: Low refractive index part (light-shielding part)
g ... High refractive index part (unit lens)
k: Intermediate layer l, m ... Outer layer

Claims (6)

In a lens sheet that is combined with a Fresnel lens sheet to form a transmissive screen, a lens is formed on at least one side,
The lens sheet has a rectangular shape in which the ratio of the long side to the short side is 16: 9, the length in the short side direction (vertical direction of the image) is x (mm), and the warp of the lens sheet in the short side direction Where y is the upper limit of the xy region surrounded by a straight line represented by the following relational expressions (1) to (4). A lens sheet having a warp amount in the short side direction between the lower limit and the lower limit.
x = 500 (mm) (1)
x = 800 (mm) (2)
y = 5.0 (mm) (3)
y = 0.043x + 7.2 (mm) (4) In a lens sheet that is combined with a Fresnel lens sheet to form a transmissive screen, a lens is formed on at least one side,
The lens sheet has a rectangular shape in which the ratio of the long side to the short side is 4 to 3, the length in the short side direction (vertical direction of the image) is x (mm), and the warp of the lens sheet in the short side direction Where y is the upper limit of the xy region surrounded by a straight line represented by the following relational expressions (5) to (8). A lens sheet having a warp amount in the short side direction between the lower limit and the lower limit.
x = 600 (mm) (5)
x = 900 (mm) (6)
y = 5.0 (mm) (7)
y = 0.064x-12.2 (mm) (8)   The lens sheet according to claim 1, wherein a center portion of the lens sheet is provided with a warp that is convex toward the Fresnel lens sheet side.   The lens sheet according to claim 1, wherein a diffusion layer is laminated on the lens sheet.   The lens sheet includes a lenticular lens in which convex cylindrical lens groups are arranged in parallel using refraction or total reflection, a lens sheet having a prism array, and a lens sheet having a microlens structure in which unit lenses are two-dimensionally arranged. The lens sheet according to claim 1, wherein the lens sheet is any one.   A transmissive screen comprising the lens sheet according to claim 1 and a Fresnel lens sheet combined so that a center portion of the lens sheet has a warp convex toward the Fresnel lens sheet.

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