JP2002287256A - Both-side lenticular lens sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a both-side lenticular lens sheet with which high-grade images of a high contrast are obtainable without entailing the degradation in screen characteristics, such as contrast, color balance and visual field angle, in spite of the occurrence of optical axis misalignment to some extent. SOLUTION: This lenticular lens sheet is formed with a multiplicity of incident surface lenticular lenses 2 in parallel on one surface of a translucent base material 4 and is formed with the exit surface lenticular lenses 1 making a pair with the respective incident surface lenticular lenses 2 in parallel on the other surface. The respective exit surface lenticular lenses 1 consist of base sections 11 of an approximately trapezoidal shape in section and lens sections 12 formed in the upper part of these base sections 11. The angle of inclination of the rising surfaces 13 of the base sections 11 is >=60 deg. and light absorption layers 3 are formed in the recessed part grooves formed between the adjacent exit surface lenticular lenses 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided lenticular lens sheet used as a screen for a projection television or a microfilm reader and a transmission screen using the same, and more particularly to a high contrast, high optical axis. The present invention relates to a lenticular lens sheet capable of providing an image excellent in color balance and viewing angle characteristics with a small decrease in screen characteristics due to displacement, and a transmission type screen using the same.

[0002]

2. Description of the Related Art A double-sided lenticular lens sheet is C
RT projector, LCD projector, DMD
(Digital micromirror device) A transmission type screen combined with a Fresnel lens sheet to form an image projected from a projection device such as a projector, and to diffuse an incident light beam to widen the viewing angle. Has been used as

As shown in FIGS. 8 and 9, a double-sided lenticular lens sheet generally used as a screen has an incident surface lenticular lens 1 formed on a light incident surface side and a light emitting surface side (observation side). The light emitting surface lenticular lens 2 and the light absorbing layer 3 formed in (1).
As shown in FIG. 8, the light absorbing layer 3 forms a ridge in the non-light-condensing region between the adjacent lenticular lenses on the exit surface, and the light absorbing layer 3 is formed on the ridge (top on the observation side). The light absorbing layer 3 may be formed in a concave portion corresponding to a non-light-condensing region between adjacent lenticular lenses on the exit surface as shown in FIG. 9, and the latter secures a wide viewing angle. In addition, the ratio (BS ratio) of the light absorbing layer 3 can be increased, which is suitable from the viewpoint of improving contrast by removing internal stray light.

However, even in a double-sided lenticular lens sheet in which the light absorbing layer 3 is formed in a concave portion corresponding to a non-light-condensing region between adjacent lenticular lenses on the exit surface, the BS is also required.
There is a problem that a sufficient improvement in contrast cannot be obtained even if the ratio is increased. This is because, in the conventional double-sided lenticular lens sheet, as shown in FIG. 9, since the shape of the concave portion forming the light absorbing layer 3 has a relatively small slope inclination angle, it is 45 ° with respect to the normal direction of the emission surface. ~ 60 °
External light incident on the double-sided lenticular lens sheet from the angle of
The light was scattered by the contained light diffusing agent and was emitted from the lenticular lens on the emission surface.

On the other hand, in video display devices such as projection televisions, in recent years, there has been an increasing demand for higher image quality and higher definition in order to cope with higher resolution of video. Under such circumstances, a double-sided lenticular lens sheet used as a transmission screen of a projection television or the like is required to have high resolution, high contrast, and a wide viewing angle.

In order to cope with such a high resolution,
It has been proposed to make the lens pitch of a double-sided lenticular lens fine (fine pitch), but it is generally used as a method for manufacturing a double-sided lenticular lens sheet such as an extrusion molding method, an injection molding method, and a press molding method. According to the method, there is a limit to the fine pitch of the lenticular lens. For this reason, JP-A-1-159627 and JP-A-3-64701 disclose a method of continuously forming lenticular lenses on both surfaces of a light-transmitting substrate using a UV-curable composition by using a cylindrical lens mold. A way to do that has been proposed.

However, in the case of producing a fine pitch double-sided lenticular lens sheet using such an ultraviolet-curable composition, the optical axis of the exit surface lenticular lens and the entrance surface lenticular lens due to the meandering of the translucent substrate or the like. This causes a problem in that a shift occurs and adversely affects screen characteristics such as viewing angle characteristics, color balance, and color unevenness. In addition, when designing a lens to allow this optical axis shift, it is necessary to lower the BS ratio, which causes a reduction in contrast.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention suppresses a decrease in contrast due to external light,
The optical axis deviation between the lenticular lens on the entrance surface and the lenticular lens on the exit surface can be tolerated without causing a decrease in contrast.
An object of the present invention is to provide a double-sided lenticular lens sheet excellent in color balance and the like and a transmission screen using the same.

[0009]

In view of such circumstances, the present inventors have considered the shape of the exit surface lenticular lens,
In particular, the inventors have found that the above problem can be solved by setting the inclination angle of the rising surface of the base within a specific range, and have reached the present invention.

That is, in the double-sided lenticular lens sheet of the present invention, a large number of incident surface lenticular lenses are formed in parallel on one surface of a light-transmitting substrate, and the other surface has an outgoing light paired with each incident surface lenticular lens. A double-sided lenticular lens sheet in which surface lenticular lenses are formed in parallel, wherein each of the exit surface lenticular lenses comprises a base having a substantially trapezoidal cross section and a lens portion formed on an upper portion of the base, and a rising surface of the base. Has an inclination angle of 60 ° or more, and a light absorbing layer is formed in a concave groove formed between adjacent lenticular lenses on the exit surface. Further, the transmission screen of the present invention is characterized by combining a double-sided lenticular lens sheet and a Fresnel lens sheet having such a configuration.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In the double-sided lenticular lens sheet according to the present invention, as shown in FIG. 1, an emission surface lenticular lens 1 made of an active energy ray-curable resin is provided on one surface of a light-transmitting base material 4 and an active energy ray-cured resin is provided on the other surface. An incident surface lenticular lens 2 made of resin is formed. Further, the light absorbing layer 3 is formed in a concave groove formed between the lenticular lenses 1 formed at regular intervals. The exit surface lenticular lens 1 includes a base 11 having a substantially trapezoidal cross section,
And a lens portion 12 formed continuously on the upper part of
The inclination angle a of the rising surface 13 of the base 11 is not less than 60 °. This corresponds to the inclination angle a of the rising surface 13.
Is set to 60 ° or more, external light incident on the double-sided lenticular lens sheet from an angle of 45 to 60 ° with respect to the normal direction of the exit surface is reflected by the entrance surface lenticular lens sheet 2 and is reflected by the exit surface lenticular lens 1. Most of the reflected light traveling in the direction of can be blocked by the concave groove filled with the light absorbing material, so that a decrease in contrast due to incidence of external light can be suppressed. The inclination angle a of the rising surface 13 is preferably in the range of 60 to 95 °,
More preferably, it is in the range of 70 to 90 °, and still more preferably in the range of 75 to 85 °.

In the present invention, the light-emitting surface lenticular lens 1 is formed by filling a concave groove with a light-absorbing material.
In order to easily scrape off excess light-absorbing material at the time of forming the lens, a shape in which a part of the upper surface of the base 11 is present as shoulders 14 at both ends of the lens as shown in FIG. However, in order to further increase the BS ratio, it is preferable that the shoulder 14 is not provided as shown in FIG. 3 so that external light reflected by the entrance surface lenticular lens 2 does not enter the office from the shoulder 14. . In the present invention,
Even when the shoulder 14 is not provided, the excess light absorbing material can be scraped off relatively easily by setting the inclination angle a of the rising surface 13 of the base 11 of the exit surface lenticular lens to 60 ° or more. .

In the present invention, the area ratio of the concave groove formed between the exit surface lenticular lenses 1 is 55%.
Preferably it is ~ 75%. That is, the width of the concave groove is set to 55, which is the lens pitch of the exit surface lenticular lens 1.
It is preferable to set it to 75%. This is because the contrast can be improved by setting the area ratio of the concave groove to 55% or more, and the output surface lenticular lens 1 and the incident surface lenticular lens 2 by setting the area ratio of the concave groove to 75% or less.
Even if the optical axis deviates slightly from the above, the light incident and condensed from the incident surface lenticular lens 2 can be emitted from the exit surface lenticular lens 1 without affecting the light absorption layer 3, and color balance and This is because it is possible to suppress a decrease in the viewing angle characteristics and the occurrence of color unevenness. The area ratio of the concave groove is more preferably in the range of 60 to 70%. In the present invention, the area ratio of the concave groove is
It refers to the area ratio of the surface including the base upper surface of the exit surface lenticular lens 1.

In the double-sided lenticular lens sheet of the present invention, the base 11 of the exit surface lenticular lens 1 is provided.
The inclination angle of the rising surface 13 is set as described above, and a concave groove is formed between the adjacent lenticular lenses 1 on the exit surface, so that 45 degrees with respect to the normal direction of the exit surface.
External light incident on the double-sided lenticular lens sheet from an angle of up to
Most of the reflected light reflected in the direction of the lenticular lens 1 at the exit surface can be blocked by the concave groove filled with the light absorbing material, so that a decrease in contrast due to the incidence of external light can be suppressed.

The rising surface 13 of the base 11 of the exit surface lenticular lens 1 emits from the exit surface lenticular lens 1 without the image light incident and condensed from the entrance surface lenticular lens 2 being applied to the light absorbing layer 3. In order to be able to perform this operation, the height H from the rising surface of the base portion to the center point of the lens portion where the horizontal distance r from the center point of the lens portion 12 of the exit surface lenticular lens 1 is r is set. It is sometimes preferable to satisfy the following expression (1). Here, L indicates the maximum width of the incident surface lenticular lens 2, and α indicates the maximum angle that allows for the maximum width L of the incident surface lenticular lens 2 (see FIG. 4).

[0016]

(Equation 4) The concave groove formed between the adjacent exit surface lenticular lenses 1 reflects external light incident on the double-sided lenticular lens sheet from the incident surface lenticular lens sheet 2 at an angle of 45 to 60 ° with respect to the normal direction of the exit surface. In order to block reflected light directed toward the exit surface lenticular lens 1 and to suppress a decrease in contrast due to the incidence of external light, the bottom surface is preferably a flat surface.
For the purpose of maintaining the transfer shape of the exit surface lenticular lens 1 or the like, as shown in FIG. 5, the cross-sectional shape near the bottom surface of the concave groove may be a V-groove or a curved surface. In this case, if the inclination angle b of the inclined surface of the V-groove is too large, the effect of suppressing a decrease in contrast due to the incidence of external light is reduced, so that the inclination angle b of the inclined surface is preferably 30 ° or less, More preferably, it is in the range of 10 to 20 °.

The light-absorbing layer 3 is formed in the concave groove by using a light-absorbing material containing a dye-based material, a carbon black-based material, a metal oxide, or a resin bead colored therewith as a light absorbing agent. This can be achieved by filling the grooves. These light absorbers are preferably contained in the range of 0.5 to 20% by weight in the case of dyes or carbon black, and in the range of 5 to 20% by weight in the case of resin beads. When using fine particles such as carbon black, metal oxides and resin beads, the particle size is 0.5 to 250 μm.
Degree, more preferably 1 to 10
It is in the range of 0 μm.

In the present invention, the material for forming the light absorbing layer 3 is not particularly limited as long as it contains the above-mentioned light absorbing agent. Since the light absorbing layer 3 can be easily formed, a material obtained by blending the active energy ray-curable composition with the light absorbing agent is filled in the concave groove, and after the excess resin is scraped off, the active energy ray such as ultraviolet rays is removed. Irradiation and curing are preferred. In particular, when the exit surface lenticular lens 1 is made of an active energy ray-curable resin, the use of the active energy ray-curable composition can form the light absorbing layer 3 having sufficient adhesion.

The active energy ray-curable composition includes:
There is no particular limitation as long as the resin is cured with an active energy ray such as an ultraviolet ray or an electron beam. For example, polyesters, epoxy resins, polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) (Meth) acrylate resins such as acrylates and the like can be mentioned. Among them, (meth) acrylate-based resins are particularly preferable from the viewpoint of adhesion to a lenticular lens sheet, optical characteristics, and the like. Examples of the ionizing radiation-curable composition used for such a cured resin include polyvalent acrylate and / or polyvalent methacrylate (hereinafter, referred to as polyvalent (meth) acrylate) in terms of handleability and curability. It is preferable to use monoacrylate and / or monomethacrylate (hereinafter, referred to as mono (meth) acrylate) and a photopolymerization initiator using active energy rays as main components. Representative polyvalent (meth) acrylates include polyol poly (meth) acrylate, polyester poly (meth) acrylate, epoxy poly (meth) acrylate, urethane poly (meth) acrylate, and the like. These are used alone or as a mixture of two or more. Examples of the mono (meth) acrylate include a mono (meth) acrylate of a monoalcohol and a mono (meth) acrylate of a polyol.

The light absorbing layer 3 formed in the concave groove is formed in the entire concave groove so as to cover the entire rising surface 13 facing the base portion 11 of the adjacent exit surface lenticular lens 1. This is preferable because the contrast can be improved. The surface of the light absorbing layer 3 is preferably flat as shown in FIG. 1, but may be a concave curved surface or a convex curved surface which does not protrude from the lenticular lens 1 at the exit surface. Further, the reflection can be prevented by roughening the surface of the light absorbing layer 3. However, since the contrast is prevented from lowering due to regular reflection on the surface of the light absorbing layer 3, the surface is not so rough. Is preferable.

In the double-sided lenticular lens sheet of the present invention, the shape of the incident surface lenticular lens 2 is not particularly limited, but it is preferable to form a gap portion 21 between the adjacent incident surface lenticular lenses 2. This is because the BS ratio can be increased and the contrast can be improved. In addition, when adjusting the light-collecting characteristics of the incident surface lenticular lens 2, when increasing the curvature in order to increase the degree of condensing the image light, the adjacent incident surface lenticular lens can be used. This is because it is difficult to form the valleys between the lenses 2, and it is difficult to form the valleys according to a predetermined shape, or to cause a defect such as a burr to cause a decrease in screen characteristics. In particular, like the double-sided lenticular lens sheet of the present invention, the light is focused by the incident surface lenticular lens 2 so that the optical axis deviation between the exit surface lenticular lens 1 and the incident surface lenticular lens 2 can be tolerated without impairing the BS ratio. In order to prevent the image light from entering the light absorbing layer 3, it is necessary to increase the curvature of the lenticular lens 2 on the incident surface to increase the degree of condensing the image light.

It is preferable that the gap 21 has a width of 10% or less of the lens pitch of the incident surface lenticular lens 2 from the viewpoint of minimizing loss of image light. More preferably in the range of 1 to 7%,
More preferably, it is in the range of 1 to 5%.

The gap 21 is preferably a flat surface from the viewpoint of minimizing the loss of image light, but may be a V-groove or a curved surface. In the case of the V-groove, the inclination angle of the inclined surface is preferably 30 ° or less in order to guide the image light incident on the gap portion 21 to the region where the light absorbing layer 3 is formed in the double-sided lenticular lens sheet. .

The lens shape of the lens section 12 of the exit surface lenticular lens 1 is based on the following aspherical expression (2).
It is preferable that the coefficient K be in the range of -1 <K <-0.6 and the coefficient C be in the range of 1.2 <| C | <1.5.
This is because, by setting the coefficient K to be larger than −1 and the absolute value of the coefficient C to be larger than 1.2, the refraction effect in the lens unit 12 can be improved and a wide viewing angle characteristic can be obtained. By making the coefficient K smaller than -0.6 and making the absolute value of the coefficient C smaller than 1.5, it is possible to prevent the color balance from being lowered on the wide-angle side due to the excessive refraction effect, and to cause a slight optical axis shift lens. This is to suppress a large change in color balance, viewing angle characteristics, and the like due to a shift in the distance. More preferably, the coefficient K is -0.9 <K <-
0.7, and the coefficient C is 1.25 <| C | <1.
4 range.

[0025]

(Equation 5)Also, the lens shape of the entrance surface lenticular lens 2 is
Based on the following aspherical expression (3), the coefficient K is -0.6 <K
<−0.3, and the coefficient C is 1.14 <| C | <
1.2 and the coefficient A₁Is -0.0 when C> 0
6 <A₁<0.04, and when C <0, −0.0.
04 <A₁It is preferable to be in the range of <0.06. This
This makes the coefficient K greater than -0.6 and the absolute value of the coefficient C
Is larger than 1.14 and the coefficient A₁To -0.06 or
By setting it larger than -0.04, the output surface wrench
Due to the excessive refraction effect at the lens portion 12 of the lens 1
Color balance on the wide-angle side.
And the coefficient K is made smaller than -0.3, and the absolute value of the coefficient C is
1.2 and the coefficient A₁0.04 or 0.0
By making it smaller than 6, the shape at the outer periphery of the lens can be reduced.
In addition to suppressing the occurrence of image defects, etc.
In the lens unit 12 of the lenticular lens 1 on the exit surface,
Improved refraction effect and wide viewing angle characteristics
It is. More preferably, the coefficient K is -0.5 <K <
−0.45, and the coefficient C is 1.14 <| C | <
1.19 and the coefficient A₁Is -0 when C> 0.
04 <A ₁<0, and 0 <A when C <0₁<
It is in the range of 0.04.

[0026] The coefficients A ₁ in the above range, it is possible to reduce the coma aberration, the light incident from outside centralized angle of 0 ° to a more central portion of the exit surface lenticular lens 1 can be condensed, Exit surface lenticular lens 1
Since the effective use area is limited at the center, the BS ratio can be increased and the contrast can be improved.

[0027]

(Equation 6) Further, in the double-sided lenticular lens sheet of the present invention, the maximum width L of the incident surface lenticular lens and the distance h between the exit surface lenticular lens 1 and the incident surface lenticular lens 2 are 1.2 <h / L <. 1.
26 is preferably satisfied. This means that h / L is 1.
This is because the color balance on the wide angle side can be improved by making the ratio larger than 2, and sufficient viewing angle characteristics can be obtained by making the ratio smaller than 1.26. Preferably, it is in the range of 1.212 <h / L <1.245.

In the present invention, the material forming the exit-side lenticular lens 1 and the entrance-side lenticular lens 2 is not particularly limited as long as it is a resin material having high light transmittance. The exit surface lenticular lens 1 and the entrance surface lenticular lens 2 can be integrally formed by using a thermoplastic resin such as. On the other hand, from the viewpoint of achieving a fine pitch of the double-sided lenticular lens, in the present invention, the light-emitting surface lenticular lens 1 made of an active energy ray-curable resin is formed on one surface of the translucent base material 4 and the active surface is formed on the other surface. It is particularly suitable for the case where the incident surface lenticular lens 2 made of energy ray curable resin is formed.

The light-transmitting substrate 4 constituting such a double-sided lenticular lens sheet is not particularly limited as long as it is a material that transmits active energy rays such as ultraviolet rays and electron beams, and a flexible glass plate or the like is used. However, a transparent resin sheet or film of a polyester resin, an acrylic resin, a polycarbonate resin, a vinyl chloride resin, a polymethacrylimide resin, or the like is preferable. In particular, polymethyl methacrylate having a low surface reflectivity, a mixture of polymethyl acrylate and polyvinylidene fluoride resin,
A resin made of a polyester resin such as a polycarbonate resin and polyethylene terephthalate is preferable. The thickness of the light-transmitting substrate 4 varies depending on its use.
Those having a range of about μm to 5 mm are used. In addition, in order to improve the adhesiveness between the light-transmitting substrate 4 and the lenticular lenses 1 and 2 on the light-exiting surface and the light-incident surface, it is preferable that the surface thereof is subjected to an adhesion improving treatment such as an anchor coat treatment.

The active energy ray-curable resin forming the exit surface lenticular lens 1 and the incident surface lenticular lens 2 is not particularly limited as long as it is cured with an active energy ray such as an ultraviolet ray or an electron beam. The same active energy ray curable composition as used in the light absorbing layer 3 described above can be used. The light-emitting surface lenticular lens 1 and the light-entering surface lenticular lens 2 are made of inorganic fine particles made of glass, silica, talc, barium sulfate or the like, or light made of organic fine particles made of acrylic resin, styrene resin, polyethylene, nylon or polycarbonate. A diffusing agent or the like can be dispersed.

Next, a method for manufacturing a double-sided lenticular lens sheet of the present invention will be described with reference to FIG.
In the figure, reference numerals 30 and 30 'denote lens molds having a lens pattern in which lenticular lens units are engraved, such as aluminum, brass, metal molds made of metal such as steel, silicone resin, polyurethane resin, epoxy resin, ABS resin,
A resin mold made of a synthetic resin such as a fluororesin or polymethylpentene resin, an electroforming mold manufactured by Ni electroforming, or the like is used.
In particular, in the case of a roll type, it is desirable to use a metal type from the viewpoint of heat resistance and strength. In the present invention,
It is not limited to the roll type, but may be a flat type flat plate. In the case of a roll type, a thin plate lens type having a lens pattern formed thereon may be used by winding it around a cylindrical roll and fixing it. Further, a cylindrical stepped lens mold in which a thin plate stepped lens mold having a thick portion formed at an end portion is wound around a cylindrical roll and fixed may be used. It is preferable to apply plating such as copper or nickel to the surface of such a lens mold in order to prevent various types of corrosion. Further, in order to make the cutting material particles uniform and fine, it is also possible to form a thick plating of copper, nickel or the like and form a lens pattern on the plating layer portion.

The first lens mold 30 is supplied with the light-transmissive substrate 4 along the lens pattern forming surface, and the first lens mold 30 is provided between the first lens mold 30 and the light-transmissive substrate 4. Of the active energy ray-curable composition 31 is continuously supplied from the resin tank 32. A nip roll 33 for uniforming the thickness of the supplied first active energy ray-curable composition 31 is provided outside the translucent substrate 4. As the nip roll 33, a metal roll, a rubber roll, or the like is used. In order to make the thickness of the first active energy ray-curable composition 31 uniform, the nip roll 33
It is preferable that the material is processed with high accuracy in terms of roundness, surface roughness, etc., and in the case of a rubber roll, the rubber hardness is 60.
Those having a hardness of at least degree are preferred. The nip roll 33 is provided with a pressure adjusting mechanism 34 to enable accurate adjustment of the thickness of the first active energy ray-curable composition 31.
Is to be operated. The pressure adjusting mechanism 11 includes a hydraulic cylinder, a pneumatic cylinder,
Although various screw mechanisms and the like can be used, a pneumatic cylinder is preferable from the viewpoint of simplicity of the mechanism. The air pressure is controlled by a pressure regulating valve or the like.

First active energy ray-curable composition 31
Is supplied between the first lens mold 30 and the light-transmitting substrate 4, and then the first active energy ray-curable composition 31 is sandwiched between the first lens mold 30 and the light-transmitting substrate 4. In this state, the active energy ray irradiating device 35 irradiates the active energy ray through the translucent substrate 4 to polymerize and cure the first active energy ray-curable composition 31 to form a lens pattern. Is transferred to form a first lenticular lens on one surface of the translucent substrate 4. As the active energy ray irradiation device 35, a chemical lamp for chemical reaction, a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, a visible light halogen lamp, or the like is used. It is preferable that the irradiation amount of the active energy ray is set so that the integrated energy at a wavelength of 200 to 600 nm becomes 0.1 to 50 J / cm ² . The active energy ray irradiation atmosphere may be air or an inert gas atmosphere such as nitrogen or argon.

Next, the light-transmissive substrate 4 having a lenticular lens formed on one surface is provided with a second lens mold 30 '.
Is supplied such that the other surface thereof is in contact with the lens pattern forming surface of the first lens device. Similarly, the second active energy ray-curable composition 3 is placed between the second lens mold 30 ′ and the light-transmitting substrate 4.
1 'is continuously supplied from the resin tank 32'. A nip roll 33 ′ operated by a pressure adjusting mechanism 34 ′ for equalizing the thickness of the supplied second active energy ray-curable composition 31 ′ is provided outside the translucent substrate 4. ing. After supplying the second active energy ray-curable composition 31 ′ between the second lens mold 30 ′ and the translucent substrate 4, the second active energy ray-curable composition 31 ′ is provided.
Is irradiated with an active energy ray from the active energy ray irradiating device 35 ′ through the light-transmitting base material 4 in a state sandwiched between the second lens mold 30 ′ and the light-transmitting base material 4. The active energy ray-curable composition 31 ′ is polymerized and cured, and a lens pattern formed in a lens shape is transferred to form a second lenticular lens on one surface of the translucent substrate 4.

The active energy ray-curable compositions 31, 3 supplied between the lens molds 30, 30 'and the transparent substrate 4
1 'is preferably maintained at a constant viscosity. The viscosity range is generally preferably in the range of 20 to 3000 mPa · S, more preferably 100 to 3000 mPa · S.
The range is 1000 mPa · S. In order to keep the viscosity of the active energy ray-curable compositions 31, 31 'constant, the outside of the resin tanks 32, 32' is controlled so that the temperature of the active energy ray-curable compositions 31, 31 'can be controlled. It is preferable to install heat source equipment such as a sheath heater and a hot water jacket inside.

The obtained double-sided lenticular lens sheet contains an additive such as a light absorbing agent into a concave portion between adjacent lenticular lenses on the exit surface by a general injection method such as a nip roll method, a gravure roll method or a curtain coating method. The active energy ray-curable composition is injected. In this case, the injection amount of the active energy ray-curable composition is not particularly limited, and is appropriately determined according to the shape and size of the lenticular lens. When the active energy ray-curable composition has spread over the entire exit surface of the lenticular lens sheet, excess resin is scraped off with a plastic squeegee knife such as silicone rubber. The amount of the active energy ray-curable composition injected into the recesses (the thickness of the light absorbing layer) can be controlled by adjusting the contact pressure of the squeegee.

After the injection of the active energy ray-curable composition into the concave portions is completed, the active energy ray-curable composition is cured by irradiating the active energy ray-curable composition from one or both surfaces of the lenticular lens sheet. Alternatively, adhesion to a light-transmitting substrate is performed.
This process can be repeated several times until the light absorbing layer 3 and the like have a required thickness.

The thus obtained double-sided lenticular lens sheet of the present invention has a lenticular lens thickness of about 50 to 1000 μm and a lens unit pitch of 5
The thickness is preferably about 0 to 1000 μm. In particular, when forming a lenticular lens with an active energy ray-curable resin, it is suitable for a fine-pitch double-sided lenticular lens sheet, and the lens unit pitch is 50 to
It is preferably in the range of 500 μm, more preferably in the range of 50 to 400 μm.

The lenticular lens sheet of the present invention can be used alone or in combination with a Fresnel lens sheet or a diffusion sheet as a transmission screen such as a projection TV.

[0040]

The present invention will be specifically described below with reference to examples. Manufacture of Double-Sided Lenticular Lens Sheet The cross-sectional shape of the lens portion of the exit-side lenticular lens is represented by the following equation (2). In the formula, K = −0.8 and C = 1.3.

[0041]

(Equation 7) The cross-sectional shape of the lens portion of the lenticular lens on the entrance surface is expressed by the following equation (2). Where K = −0.43, C = 1.1
8, A ₁ = −0.02.

[0042]

(Equation 8) The lens patterns of both the exit-side lenticular lens and the entrance-side lenticular lens having the shape shown in FIG. 7 are formed on the surface of a JIS brass three-type plate having a thickness of 2 mm, 480 mm × 400 mm, and subjected to Kanigen plating. Two lens flat molds were prepared for a lens and an exit surface lenticular lens. This lens flat mold was wound and fixed on a metal roll to produce two roll molds for manufacturing a double-sided lenticular lens sheet.

The active energy ray-curable compositions constituting the lenticular lens 1 and the lenticular lens 2 on the exit surface were 45 parts by weight of phenoxy acrylate (Biscoat # 192, manufactured by Osaka Organic Chemical Industry Co., Ltd.) and bisphenol A-epoxy acrylate (Kyoeisha). 55 parts by weight of epoxy ester 3000A manufactured by Yushi Kagaku Kogyo KK, 2
-Hydroxy-2-methyl-1-phenyl-propane-
1-one (Darocur 1173 manufactured by Ciba-Geigy)
An acrylic monomer mixture to which 5 parts by weight and 5 parts by weight of crosslinked methacrylic resin fine particles (MBX-5, manufactured by Sekisui Chemical Co., Ltd.) having a weight average particle diameter of 8 μm was prepared was prepared.

Next, as the light-transmitting substrate 4, a thickness of 188 μm was used.
m, a polyethylene terephthalate resin film having a refractive index of 1.60, and the distance between the lenticular lens on the light incident surface and the lenticular lens on the light emitting surface is 462.
6 μm using the above-mentioned metal roll mold so that
The lenticular lens sheet shown in FIG. 7 was manufactured using the manufacturing apparatus shown in FIG. The obtained double-sided lenticular lens sheet has a BS ratio of 61% and a maximum of 14%.
An optical axis shift of μm has occurred.

Next, an ultraviolet-curable composition (XVL-90 manufactured by Kyoritsu Chemical Industry Co., Ltd.) mixed with 10% by weight of carbon black (light-absorbing agent) was used to form an ultraviolet-curable composition for forming a light absorbing layer on a screen printer (Tokai). Screen SSP86
0AN), a suitable amount is injected into the concave groove on the exit surface of the double-sided lenticular lens sheet, and the ultraviolet curable composition is spread over the entire sheet with a squeegee knife made of silicon rubber while the concave between adjacent lenticular lenses is spread. The grooves were filled. Then, from the exit surface lenticular lens side, 8
Ultraviolet rays were irradiated by three ultraviolet lamps (manufactured by Western Quartz Co., Ltd.) having a power of 0 W / cm and an irradiation intensity of 6.4 kW to cure the ultraviolet curable composition and to make a close contact between the lenticular lenses on the exit surface.

When the obtained double-sided lenticular lens sheet and Fresnel lens sheet were combined and used as a projection TV screen, a high-quality image having high contrast and excellent color balance, viewing angle characteristics and resolution was obtained. Was done.

[0047]

As described above, the present invention provides a double-sided lenticular capable of obtaining a high-contrast, high-quality image without deteriorating screen characteristics such as contrast, color balance, and viewing angle characteristics even if a certain degree of optical axis shift occurs. The present invention can provide a lens sheet and a transmission screen using the same.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a double-sided lenticular lens sheet of the present invention.

FIG. 2 is a cross-sectional view of an exit surface lenticular lens of the double-sided lenticular lens sheet of the present invention.

FIG. 3 is a cross-sectional view of an exit surface lenticular lens of the double-sided lenticular lens sheet of the present invention.

FIG. 4 is a sectional view of a lens unit of the double-sided lenticular lens sheet of the present invention.

FIG. 5 is a cross-sectional view of an exit surface lenticular lens of the double-sided lenticular lens sheet of the present invention.

FIG. 6 is a schematic view of an apparatus for manufacturing a double-sided lenticular lens sheet according to the present invention.

FIG. 7 is a partial sectional view of the double-sided lenticular lens sheet of the present invention.

FIG. 8 is a partial sectional view showing a conventional double-sided lenticular lens sheet.

FIG. 9 is a partial sectional view showing a conventional double-sided lenticular lens sheet.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 outgoing surface lenticular lens 2 incoming surface lenticular lens 3 light absorbing layer 4 translucent substrate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 5/00 G02B 5/00 B // B29L 9:00 B29L 9:00 11:00 11:00

Claims (12)

[Claims] 1. A light-transmitting base material having a plurality of incident surface lenticular lenses formed in parallel on one surface and an outgoing surface lenticular lens paired with each incident surface lenticular lens on the other surface. A double-sided lenticular lens sheet, wherein each emission surface lenticular lens comprises a base having a substantially trapezoidal cross section and a lens portion formed on the top of the base, and an inclination angle of a rising surface of the base is 60 ° or more. A double-sided lenticular lens sheet, wherein a light-absorbing layer is formed in a concave groove formed between adjacent light-emitting lenticular lenses. 2. The inclination angle of the rising surface of the base is 60 to 85 °.
The double-sided lenticular lens sheet according to claim 1, wherein: 3. The double-sided lenticular lens sheet according to claim 1, wherein an area ratio of the concave groove is 55 to 75%. 4. The exit surface lenticular lens has a maximum width L of the entrance surface lenticular lens, a maximum angle α that allows for the maximum width L of the entrance surface lenticular lens, and a horizontal angle from the center point of the lens portion of the exit surface lenticular lens. 4. A shape satisfying the following expression (1), where H is a height from a rising surface of the base having a directional distance of r to a center point of the lens unit. The double-sided lenticular lens sheet according to any one of the above. (Equation 1) 5. The light absorbing layer formed in the concave groove is formed in the entire concave groove so as to cover the entire rising surface facing the base of the adjacent incident surface lenticular lens. Item 5. A double-sided lenticular lens sheet according to any one of Items 1 to 4. 6. A lens pitch of one of the lens pitches of an incident surface lenticular lens between adjacent incident surface lenticular lenses.
The double-sided lenticular lens sheet according to any one of claims 1 to 5, wherein a gap having a width of 0% or less is formed. 7. The double-sided lenticular lens sheet according to claim 6, wherein the gap formed between the adjacent incident surface lenticular lenses is any one of a flat surface, a V-groove, and a curved surface. 8. The double-sided lenticular lens sheet according to claim 1, wherein the lens portion of the exit surface lenticular lens has a shape represented by the following equation (2). (Equation 2) Where K is -1 <K <-0.6, C is 1.2 <|
C | <1.5. 9. The lenticular lens according to claim 1, wherein the entrance surface lenticular lens has a shape represented by the following equation (3).
The double-sided lenticular lens sheet according to any one of Items 1 to 8, (Equation 3) Where K is -0.6 <K <-0.3, C is 1.1
4 <| C | <1.2, A 1 is, C> when 0 -0.06
<A ₁ <0.04, and −0.0 when C <0.
4 <A ₁ <0.06. 10. The ratio (h / L) of the maximum width (L) of the entrance surface lenticular lens to the distance (h) between the entrance surface lenticular lens and the exit surface lenticular lens.
10. The double-sided lenticular lens sheet according to claim 7, wherein is larger than 1.2 and smaller than 1.26. 11. A lenticular lens having an incident surface formed of an active energy ray-curable resin on one surface of a light-transmissive base material, and a lenticular lens having an exit surface formed of an active energy ray-curable resin on the other surface. The double-sided lenticular lens sheet according to claim 1. 12. A transmissive screen comprising a combination of the double-sided lenticular lens sheet according to claim 1 and a Fresnel lens sheet.