JP2013152370A - Light control sheet, and transmission type screen and rear projection type display device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light control sheet in which, if at least part of a video light emission surface of the light control sheet has a curvature radius of 250 mm or more and 1500 mm or less, its appearance is not impaired and excellent video can be displayed, and a transmission type screen and a rear projection type display device having the light control sheet.SOLUTION: A unit light transmission part constituting part of the light control sheet is formed from a light transmissive resin having a coefficient of extension of 15% or more and 50% or less, and a unit light absorption part constituting part of the light control sheet is formed from a resin having a coefficient of extension of 15% or more and 40% or less and a coefficient of viscosity of 1700 mPa S or more and 3500 mPa S or less.

Description

  The present invention relates to a light control sheet, a transmissive screen provided with the light control sheet, and a rear projection display device.

  2. Description of the Related Art A rear projection display device that projects and displays video light from the back side of a screen uses a transmission screen that transmits the projected video light and displays an image. As such a transmission screen, screens of various structures have been proposed. For example, a plurality of unit light transmission units and a plurality of band-shaped unit light absorption units alternately arranged with the unit light transmission units are provided. The thing provided with the light control sheet | seat which has is proposed (for example, refer patent document 1 and patent document 2).

Here, the unit light transmission part has a function of transmitting image light projected from the back side of the transmission screen, and the unit light absorption part is a stray light that causes a double image or external light. It has a function of improving contrast by absorbing light and the like.
In order to improve contrast, the unit light absorbing section has a cross-sectional shape such as a V-shaped groove pointed toward the back side of the transmission screen or a trapezoidal groove. A shape is preferred.

  On the other hand, in the field of automobiles, for example, design is very important. At present, a rear projection display device applied to such a field is not only expected to have a function of displaying an image, but also requires harmony with the entire system in terms of design. From such a viewpoint of design, development of a transmissive screen having a curved surface shape is desired.

JP 2003-50307 A JP 2003-57416 A

  However, when the transmissive screen is formed in a curved surface shape as described above, a crack may occur between the unit light transmitting part and the unit light absorbing part constituting the light control sheet, and the appearance may be impaired. . When a crack occurs, when image light is projected onto a transmission screen, the crack portion is displayed as a streak, which may make it difficult to display a good image.

In addition, as described above, the unit light absorbing portion may have a V-shaped groove shape or a trapezoidal groove shape whose cross-sectional shape is pointed toward the back side of the transmissive screen. Although it is preferable, when the viscosity of the resin constituting the unit light absorbing portion is too low, it is impossible to satisfactorily form or hold a bank (liquid puddle) when filling the groove with the resin. On the other hand, when the viscosity of the resin is too high, the resin may not be filled up to the bottom of the groove (for example, the V-shaped tip).
When the resin filling is incomplete, the function as the unit light absorbing portion is deteriorated, and there is a problem that the contrast of the transmission screen is lowered and a good image cannot be displayed.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce the appearance even when at least a part of the image light exit surface of the light control sheet has a curvature radius of 250 mm to 1500 mm. It is an object of the present invention to provide a light control sheet that can display a good image without being damaged, a transmissive screen including the same, and a rear projection display device.

  That is, the invention according to claim 1 of the present invention is a light control sheet used for a transmission screen that transmits image light projected from an image light source and emits the image light to an observer side, and the light control sheet includes: At least a part of the image light exit surface is bent so as to have a radius of curvature of 250 mm or more and 1500 mm or less, and a plurality of unit light transmitting portions constituting a part of the image light exit surface, and one of the image light exit surfaces And a plurality of unit light absorbing portions that are alternately arranged with the unit light transmitting portions and have a height of 80 μm or more and 150 μm or less, and the unit light transmitting portions are 15% or more and 50% It is made of a light transmissive resin having the following elongation rate, the unit light absorbing portion is made of a resin containing a light absorbing material, and the resin containing the light absorbing material has an elongation rate of 15% or more and 40% or less. And 1700 The light control sheet has a viscosity of mPa · s to 3500 mPa · s.

  In the invention according to claim 2 of the present invention, the surface tension of the resin containing the light absorbing material constituting the unit light absorbing portion is larger than the surface tension of the light transmitting resin constituting the unit light transmitting portion. The light control sheet according to claim 1, wherein the light control sheet is small.

  The invention according to claim 3 of the present invention is a transmission screen that transmits image light projected from an image light source and emits the image light to an observer side, and the light control according to claim 1 or 2. A transmissive screen comprising a laminate having a sheet and a light diffusion layer disposed on the image light output side of the light control sheet, wherein the entire laminate is bent so as to form a curved surface. .

  The invention according to claim 4 of the present invention is the transmissive screen according to claim 3, wherein the entire laminate is bent so as to form a three-dimensional curved surface.

  The invention according to claim 5 of the present invention further includes a Fresnel lens sheet having a Fresnel lens portion, which is disposed closer to the video light source than the laminate, and the Fresnel lens sheet is bent so as to form a curved surface. The transmissive screen according to claim 3 or 4, wherein the transmissive screen is provided.

  The invention according to claim 6 of the present invention is characterized in that the unit light transmission part and the unit light absorption part extend in a lateral direction of the transmission type screen. It is a transmissive screen.

  Further, the invention according to claim 7 of the present invention is such that the Fresnel lens portion is optically centered at a position that is eccentric to the lower side in the longitudinal direction of the transmission screen with respect to the center of the Fresnel lens portion forming surface of the Fresnel lens sheet. The transmissive screen according to claim 5, further comprising:

  In the invention according to claim 8 of the present invention, the unit light transmission part and the unit light absorption part are substantially parallel to a direction connecting the center of the Fresnel lens part forming surface and the optical center of the Fresnel lens part. And arranged alternately in a first direction along the image light exit surface, substantially orthogonal to the first direction, and in a second direction along the image light exit surface The transmissive screen according to claim 5, wherein the transmissive screen is extended.

  According to a ninth aspect of the present invention, there is provided the transmissive screen according to any one of the third to eighth aspects and the rear side of the transmissive screen, and an image is displayed on the transmissive screen. A rear projection display device comprising: an image light source that projects light.

  The invention according to claim 10 of the present invention further includes an infrared light source that projects infrared light on the transmission screen, and an infrared light detector capable of detecting the infrared light. The rear projection display device according to claim 9.

  According to the present invention, the unit light transmission part of the light control sheet is made of a light transmissive resin having an elongation of 15% or more and 50% or less, and the unit light absorption part of the light control sheet contains a light absorbing material. Since the resin containing the light absorbing material is made of resin and has an elongation of 15% or more and 40% or less, the radius of curvature of at least a part of the image light exit surface of the light control sheet is 250 mm or more and 1500 mm or less. Even when the light control sheet is curved so as to have a crack, the occurrence of cracks between the unit light transmitting part and the unit light absorbing part can be suppressed. Therefore, in the light control sheet according to the present invention, the appearance is not impaired, and a good image can be displayed on the transmissive screen provided with the light control sheet according to the present invention.

According to the invention, the unit light absorbing portion of the light control sheet is made of a resin containing a light absorbing material, and the resin containing the light absorbing material has a viscosity of 1700 mPa · s to 3500 mPa · s. Therefore, even when the elongation rate as described above is applied to the light-transmitting resin and the resin containing the light absorbing material, the composition constituting the resin containing the light absorbing material is V-shaped or The trapezoidal groove can be satisfactorily filled.
Therefore, the transmissive screen provided with the light control sheet according to the present invention has excellent contrast and can display a good image.

It is a typical perspective view of the transmission type screen concerning a 1st embodiment. It is a schematic block diagram of the transmission type screen which concerns on 1st Embodiment. It is sectional drawing when a transmission type screen is cut | disconnected along the II line | wire of FIG. FIG. 3 is a schematic perspective view of the Fresnel lens sheet shown in FIG. 2. FIG. 3 is a plan view of the Fresnel lens sheet when the Fresnel lens sheet shown in FIG. 2 is viewed from the image light emitting side. It is a figure which shows the Fresnel lens sheet of the other aspect which concerns on 1st Embodiment. FIG. 3 is a schematic perspective view of the light control sheet shown in FIG. 2. It is sectional drawing when a light control sheet is cut | disconnected along the II-II line | wire of FIG. It is the figure which showed typically the manufacturing process of the transmission type screen which concerns on 1st Embodiment. It is the figure which showed typically the manufacturing process of the transmission type screen which concerns on 1st Embodiment. It is the figure which showed typically the manufacturing process of the transmission type screen which concerns on 1st Embodiment. It is typical sectional drawing of the rear projection type display apparatus which concerns on 1st Embodiment. It is the figure which showed typically the manufacturing process of the transmissive screen which concerns on 2nd Embodiment. It is typical sectional drawing of the rear projection type display apparatus which has a touch-panel function which concerns on 3rd Embodiment. It is the figure which looked at the rear projection type display apparatus which has a touch-panel function which concerns on 3rd Embodiment from upper direction.

(First embodiment)
<Light control sheet and transmissive screen>
First, a light control sheet and a transmission screen according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view of a transmissive screen according to the present embodiment, FIG. 2 is a schematic configuration diagram of the transmissive screen according to the present embodiment, and FIG. 3 is taken along line II in FIG. It is sectional drawing when a transmission type screen is cut. 4 is a schematic perspective view of the Fresnel lens sheet shown in FIG. 2, and FIG. 5 is a plan view of the Fresnel lens sheet when the Fresnel lens sheet shown in FIG. 2 is viewed from the image light emitting side. 6 is a diagram showing a Fresnel lens sheet according to another aspect of the present embodiment, FIG. 7 is a schematic perspective view of the light control sheet shown in FIG. 2, and FIG. 8 is taken along the line II-II in FIG. It is sectional drawing when a light control sheet is cut along.

  The transmissive screen 10 shown in FIGS. 1 and 2 includes a Fresnel lens sheet 20 and a laminate 30 disposed on the image light emitting side of the Fresnel lens sheet 20.

  The Fresnel lens sheet 20 and the laminate 30 shown in FIGS. 1 and 2 are bent so as to form a curved surface. The curvature radius is appropriately selected depending on the application, but the entire Fresnel lens sheet 20 and the laminate 30 are preferably bent so that at least a part thereof has a curvature radius of 250 mm or more and 1500 mm or less.

Further, the Fresnel lens sheet 20 and the laminated body 30 are bent so as to form a two-dimensional curved surface or a three-dimensional curved surface. Preferably, the Fresnel lens sheet 20 and the laminated body 30 are bent so as to form a three-dimensional curved surface as shown in FIGS. 1 and 2.
Here, in the present specification, the “two-dimensional curved surface” is a two-dimensional curve around a single axis, or a two-dimensional curve with different curvatures around a plurality of parallel axes. In addition, the term “three-dimensional curved surface” means that it is partially or entirely bent around a plurality of axes inclined with respect to each other.

In the present embodiment, as shown in FIG. 1, the Fresnel lens sheet 20 and the laminate 30 are first parallel to one diagonal line and positioned on the back side (image light incident side) of the transmissive screen 10. Bends in a direction d1 centered on the axis A1, and also in a direction d2 centered on a second axis A2 that is parallel to the other diagonal line and located on the back side (image light incident side) of the transmissive screen 10 . As a result, the transmissive screen 10 is bent so as to be convex toward the viewer side, and the image light of the transmissive screen 10 is at a central position P where a pair of rectangular diagonal lines forming the planar shape of the transmissive screen 10 intersect. The emission surface 10a (display surface) protrudes most to the viewer side.
The transmission screen 10 shown in FIG. 1 is bent so as to be convex toward the viewer side. However, the transmission screen according to the present invention is not limited to this, and is concave toward the viewer side. It may be bent so as to be convex toward the back side, or it may be a combination of a portion bent so as to be convex toward the observer side and a portion bent so as to be convex toward the back side Good.

<Fresnel lens sheet>
The Fresnel lens sheet 20 shown in FIGS. 2 and 3 includes a base portion 21 and a Fresnel lens portion 22 formed on the surface of the base portion 21.

The Fresnel lens unit 22 has a function of deflecting the traveling direction of the image light projected on the transmission screen 10 as a divergent light beam from an image light source (not shown). Specifically, as shown in FIG. 3, the Fresnel lens unit 22 causes the image light L ₁ that has entered as a divergent light beam to travel in a parallel light beam that travels from the image light incident side to the image light emission side, for example, in the front direction N. Convert to a traveling parallel beam. As described above, once the image light is collimated once using the Fresnel lens unit 22, the in-plane variation in the brightness of the image observed by the observer, in particular, the image observed from the oblique direction by the observer. Can be effectively relieved.

  In the present embodiment, as shown in FIGS. 4 and 5, the Fresnel lens unit 22 is configured as a so-called circular Fresnel lens. However, the present invention is not limited to this, and it may be configured as a so-called linear Fresnel lens. In the linear Fresnel lens, each of the plurality of unit lenses extends linearly, and the plurality of unit lenses are arranged in an arrangement direction intersecting with the longitudinal direction thereof.

As shown in FIG. 5, the Fresnel lens portion 22 preferably has an optical center O ₂ at a position decentered with respect to the center O ₁ of the Fresnel lens portion forming surface 20 a of the Fresnel lens sheet 20. Specifically, the Fresnel lens portion 22 is composed of a plurality of unit prisms 23 that are concentric arcs or concentric circles centered on the optical center O ₂ .

  Here, the “Fresnel lens part forming surface” is a surface on which the Fresnel lens part is formed in the Fresnel lens sheet. When the Fresnel lens sheet is a refractive type Fresnel lens sheet, the Fresnel lens part forming surface. Is located on the image light exit side. When the Fresnel lens sheet is a total reflection type Fresnel lens sheet described later, the Fresnel lens portion forming surface is located on the image light incident side.

The optical center O ₂ of the Fresnel lens portion 22 shown in FIG. 5 exists at a position away from the Fresnel lens sheet 20. For example, when an image light source (not shown) is disposed below the transmissive screen 10, the optical center O ₂ is outside the Fresnel lens sheet 20 and at the center O ₁ of the Fresnel lens portion forming surface 20a. On the other hand, it exists at a position on the lower side in the vertical direction of the transmissive screen 10.
In the above description, the optical center O ₂ exists at a position away from the Fresnel lens sheet 20, but may exist in the Fresnel lens sheet 20.

  Here, in this specification, the “vertical direction” of the transmissive screen 10 means the vertical direction of the viewer when the viewer views the transmissive screen 10 from the front. 10 "lateral direction" means the left-right direction of the observer when the observer views the transmission screen 10 from the front.

Even when the distance between the Fresnel lens sheet 20 and the image light source is shortened by forming the Fresnel lens portion 22 with the optical center O ₂ decentered in this way, the image light is transmitted from the image light incident side to the image light. It can be converted into a parallel light beam traveling toward the emission side, for example, a parallel light beam traveling in the front direction N shown in FIG.

In the above description, the embodiment using the Fresnel lens portion 22 in which the optical center O ₂ is decentered with respect to the center O _{1 of the} Fresnel lens portion forming surface 20a has been described. It is also possible to use a Fresnel lens part that is not decentered with respect to the center of the Fresnel lens part forming surface.

  In the above description, the example in which the Fresnel lens sheet 20 is a so-called refractive type Fresnel lens is described. However, the present invention is not limited to this, and a total reflection type Fresnel lens sheet may be used. It is.

  As shown in FIG. 6, the total reflection type Fresnel lens sheet 24 totally reflects at least a part of the refracting surface 25a that refracts incident image light and the image light refracted by the refracting surface 25a. A plurality of unit prisms 25 having total reflection surfaces 25b directed to the light emitting side are provided. When the total reflection type Fresnel lens sheet 24 is used, the distance between the image light source and the Fresnel lens sheet 24 can be further reduced, so that a thinner rear projection display device can be provided.

  As shown in FIGS. 2 to 4, the Fresnel lens sheet 20 may have an incident-side transparent base material 26 for reinforcing the Fresnel lens sheet 20 on the image light incident side with respect to the base portion 21. The incident-side transparent base material 26 and the base portion 21 are bonded to each other via a bonding layer (not shown) made of an adhesive such as an adhesive or an ultraviolet curable adhesive.

  Similar to the Fresnel lens sheet 20, the incident-side transparent substrate 26 is bent so as to form a curved surface. Examples of the incident-side transparent base material 26 include base materials made of a transparent resin such as an acrylic resin, a styrene resin, a polyester resin, a polycarbonate resin, and an acrylic-styrene copolymer resin.

  The thickness of the incident-side transparent base material 26 is preferably 1.0 mm to 4.0 mm, and more preferably 1.5 mm to 2.0 mm. This is because if the thickness of the incident-side transparent base material 26 is less than 1.0 mm, the function as a reinforcing member may not be sufficiently achieved. If the thickness exceeds 4.0 mm, the reason will be described next. This is because a double image is easily recognized by an observer. That is, when the thickness of the Fresnel lens sheet is thick, the distance between the image light emitted from the Fresnel lens sheet and the stray light is larger than when the thickness of the Fresnel lens sheet is thin. Are easily recognized as double images. Therefore, even if the Fresnel lens sheet 20 has the same thickness, if the incident-side transparent base material 26 is thick, the observer can easily recognize a double image.

<Laminated body>
As the configuration of the laminated body 30, for example, as shown in FIGS. 2 and 3, the transparent base 35, the bonding layer 40, the light control sheet 45, in order from the image light incident side to the image light output side, Examples include those having the bonding layer 50, the light diffusion layer 55, and the surface layer 60.
In the present invention, the laminate 30 only needs to have the light control sheet 45 and the light diffusion layer 55, and does not have to have the transparent base material 35, the bonding layers 40 and 50, and the surface layer 60. .

<Transparent substrate>
The transparent substrate 35 described above increases the rigidity of the transmission screen 10. Here, it is possible to increase the thickness of the incident-side transparent base material 26 of the Fresnel lens sheet 20 and increase the rigidity of the transmissive screen 10, but when the thickness of the incident-side transparent base material 26 is increased, The double image is easily recognized by the observer. Therefore, rather than increasing the thickness of the incident-side transparent base material 26 and increasing the rigidity of the transmissive screen 10, it is better for the observer to arrange the transparent base material 35 and increase the rigidity of the transmissive screen 10. This is effective because the image is not easily recognized. Moreover, since the rigidity of the transmissive screen 10 can be increased by disposing the transparent base material 35, the thickness of the incident-side transparent base material 26 can be further reduced, and the double image is further hardly recognized.

  The thickness of the transparent substrate 35 is preferably 1.5 mm or more, and more preferably 3 mm or more. This is because if the thickness of the transparent substrate 35 is less than 1.5 mm, the function of increasing the rigidity of the transmission screen 10 may not be sufficiently achieved.

  Examples of the transparent substrate 35 include a substrate made of a transparent resin such as an acrylic resin, a styrene resin, a polyester resin, a polycarbonate resin, and an acrylic-styrene copolymer resin.

<Light control sheet>
The light control sheet 45 is disposed on the image light emission side (observer side) of the transparent substrate 35. The light control sheet 45 transmits image light incident on the light control sheet 45 and absorbs stray light that causes a double image. Although the light control sheet 45 varies depending on the application, at least a part of the image light exit surface 45a shown in FIGS. 7 and 8 has a radius of curvature of 250 mm or more and 1500 mm or less from the viewpoint of improving the design.

  As shown in FIGS. 3, 7, and 8, the light control sheet 45 includes a base part 46, a plurality of unit light transmission parts 47 that are formed on the base part 46 and transmit incident video light, A plurality of unit light absorbing portions 48 that are formed between the plurality of unit light transmitting portions 47 and absorb stray light are provided.

  The base material portion 46 constitutes the image light incident surface 45b of the light control sheet 45 as shown in FIG. As shown in FIG. 8, the unit light transmitting portion 47 and the unit light absorbing portion 48 constitute the image light exit surface 45a of the light control sheet 45, and are arranged along the image light exit surface 45a. . Further, as shown in FIG. 7, the unit light transmitting portions 47 and the unit light absorbing portions 48 extend in the horizontal direction of the transmissive screen 10 and are alternately arranged in the vertical direction of the transmissive screen 10. .

Further, in the arrangement relationship between the light control sheet 45 and the Fresnel lens sheet 20, the unit light transmitting portion 47 and the unit light absorbing portion 48 have the center O ₁ of the Fresnel lens portion forming surface 20 a and the optical center O of the Fresnel lens portion 22. ₂ are arranged in parallel with each other in a first direction along the image light exit surface 45a. In this case, the unit light transmitting portion 47 and the unit light absorbing portion 48 extend in a second direction substantially orthogonal to the first direction and along the image light emitting surface 45a. Here, in FIG. 1 and the like, the “first direction” and the “vertical direction” and the “second direction” and the “lateral direction” coincide with each other, but the “first direction” and the “second direction” are the same. The “direction” is for expressing the positional relationship between the light control sheet 45 and the Fresnel lens sheet 20, and the “first direction” and “vertical direction” and the “second direction” and “lateral direction” are not necessarily one. You don't have to.

  The base material portion 46 is a layer serving as a base for forming the unit light transmitting portion 47 and the unit light absorbing portion 48.

  As the base material portion 46, a transparent resin film, a transparent resin plate, a transparent resin sheet, or transparent glass can be used. Transparent resin films include triacetate cellulose (TAC) film, polyester film such as polyethylene terephthalate (PET), diacetyl cellulose film, acetate butyrate cellulose film, polyethersulfone film, polyacrylic resin film, polyurethane resin film Polyester film, polycarbonate film, polysulfone film, polyether film, polymethylpentene film, polyether ketone film, (meth) acrylonitrile film, etc. can be suitably used. Among these, polyester films are preferably used. . Examples of the polyester film include polyethylene terephthalate, polybutylene terephthalate, polynaphthalene terephthalate, and polytrimethylene terephthalate.

<Unit light transmission part>
The unit light transmitting portion 47 has a substantially trapezoidal cross-sectional shape in the thickness direction of the light control sheet 45. In this trapezoid, the image light exit surface 45a is an upper base, and the image light incident side is a lower base that is longer than the upper base.

  The unit light transmitting portion 47 is made of a light transmitting resin having an elongation of 15% to 50%, preferably 20% to 50%. The reason why this numerical value range is used is that if the elongation percentage of the light-transmitting resin is less than 15%, it may not be possible to suppress the occurrence of cracks between the unit light transmitting part and the unit light absorbing part. is there. Moreover, it is because there exists a possibility that the problem in manufacture may arise when the elongation rate of light transmissive resin exceeds 50%. That is, the unit light transmitting part can be formed by supplying the light transmitting part composition to a mold having a groove corresponding to the shape of the unit light transmitting part and curing it to obtain a light transmitting resin. However, when the elongation percentage of the light-transmitting resin exceeds 50%, it becomes difficult to peel off the unit light transmitting portion from the mold.

Here, the “elongation rate” in the present specification refers to a strip-shaped film specimen having a length of 10 cm, a width of 1 cm, and a thickness of 150 mm using a resin to be measured, and the film specimen is It means the elongation (%) when the film specimen is broken by pulling at a pulling speed of 200 mm / min in the length direction at 100 ° C. using a tensile tester. Specifically, the elongation (%) is obtained by the following formula.
Elongation rate (%) = (film specimen length at break-film specimen length before test (10 cm)) / film specimen length before test (10 cm)) × 100

  Although it does not specifically limit as light transmissive resin, For example, hardened | cured materials, such as an ionizing radiation curable resin composition which has the characteristics hardened | cured by ionizing radiations, such as an electron beam and an ultraviolet-ray, are mentioned.

  Examples of the base resin contained in the ionizing radiation curable resin composition include relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, Examples thereof include (meth) allylates of polyfunctional compounds such as polyhydric alcohols. Among these, urethane resin acrylate (urethane acrylate) and epoxy resin acrylate (epoxy acrylate) are preferable. The ionizing radiation curable resin composition may contain a reactive diluent such as a (meth) acrylate monomer. When the ionizing radiation curable resin composition is an ultraviolet curable resin composition, a polymerization initiator, a photosensitizer, or the like is mixed in the composition.

  A light transmissive resin having an elongation of 15% or more and 50% or less can be obtained by changing the degree of crosslinking of the light transmissive resin. Specifically, a light-transmitting resin having an elongation of 15% or more and 50% or less can be obtained by lowering the degree of cross-linking than the light-transmitting resin constituting the conventional unit light transmitting portion. The degree of crosslinking can be changed by preparing a crosslinking agent, a polymerization initiator, a base resin, and the like.

<Unit light absorber>
The unit light absorber 48 has a height H of 80 μm or more and 150 μm or less as shown in FIG. The unit light absorbing portion 48 is preferably formed in a groove having a V-shaped cross section or a trapezoidal groove formed by the unit light transmitting portions 47 adjacent to each other. That is, in the case where the cross-sectional shape is a V-shaped groove, the unit light absorbing portion 48 has a substantially triangular shape in which the cross-sectional shape in the thickness direction of the light control sheet 45 has the image light exit surface 45a as a base. In the case where the shape is a trapezoidal groove, the image light incident side of the light control sheet 45 is the upper base and the image light exit surface 45a of the light control sheet 45 is the lower bottom. Here, the length of the “lower bottom” is longer than the length of the “upper bottom”.

  The unit light absorbing portion 48 can be made of a resin containing a light absorbing material or the like. Examples of the resin include a cured product of an ionizing radiation curable resin composition. As this ionizing radiation curable resin composition, the same ionizing radiation curable resin composition as that for forming the unit light transmitting portion 47 can be used.

  The light absorbing material only needs to have a function of absorbing visible light or stray light, and examples of the light absorbing material include metal salts such as carbon black, graphite, and black iron oxide, pigments or dyes, and pigments. Or the resin particle colored with dye is mentioned.

  When the light absorbing material is resin particles colored with a pigment or dye, the resin particles include plastic beads such as melamine beads, acrylic beads, acrylic-styrene beads, polycarbonate beads, polyethylene beads, polystyrene beads, etc. Of these, acrylic beads are preferred.

  In the present invention, the resin containing the light absorbing material or the like constituting the unit light absorbing portion 48 is 15% or more and 40% or less, preferably 20% or more and 40% or less in a state containing the light absorbing material or the like. It is preferable to have. This is for more reliably suppressing the occurrence of cracks between the unit light transmission part and the unit light absorption part. In addition, when the elongation percentage of the resin containing the light absorbing material or the like constituting the unit light absorbing portion 48 is less than 15%, the generation of cracks between the unit light transmitting portion and the unit light absorbing portion is more reliably suppressed. There is a risk that it cannot be done. Further, as described above, since the elongation percentage of the light transmitting resin constituting the unit light transmitting portion 47 is 15% or more and 50% or less, the resin containing the light absorbing material or the like constituting the unit light absorbing portion 48. If the elongation percentage of the light control sheet exceeds 40%, the light control sheet becomes too soft, and there is a possibility that desired hardness cannot be obtained as the whole light control sheet.

  Similarly to the above light-transmitting resin, in order to adjust the elongation of the resin containing the light absorbing material to 15% or more and 40% or less, the degree of crosslinking of the resin containing the light absorbing material or the like is changed. It can be adjusted with.

Moreover, it is preferable that resin containing the light absorption material etc. which comprise the unit light absorption part 48 has a viscosity of 1700 mPa * s or more and 3500 mPa * s or less in the state containing a light absorption material etc.
When the viscosity is less than 1700 mPa · s, when filling the V-shaped or trapezoidal groove serving as the unit light absorber 48 with the solvent containing the ionizing radiation curable resin composition, a bank (liquid puddle) is used. May not be formed satisfactorily.
On the other hand, when the viscosity exceeds 3500 mPa · s, it becomes difficult to fill the ionizing radiation curable resin composition into the deep part (tip part) of the V-shaped or trapezoidal groove, and the formed light absorption The shape may be incomplete. In addition, the light absorption unit cannot sufficiently absorb external light and stray light, and the contrast may be reduced.
In addition, in this specification, "viscosity" shall mean the value measured in 25 degreeC environment using the B-type viscosity meter according to the method based on JISK7117-1.

Further, the resin containing the light absorbing material or the like constituting the unit light absorbing portion 48 is in a state containing the light absorbing material or the like, and its surface tension is the surface tension of the light transmitting resin constituting the unit light transmitting portion 47. Is preferably smaller.
When the surface tension of the resin containing the light absorbing material and the like constituting the unit light absorbing portion 48 is larger than the surface tension of the light transmitting resin constituting the unit light transmitting portion 47, the paintability is deteriorated, This is because the filling into the V-shaped or trapezoidal grooves may be defective.

In this specification, “surface tension” means a value measured at 25 ° C. by the Wilhelmy method (plate method), and a probe (plate) suspended in the composition (liquid) to be measured. The force with which the probe is drawn into the composition when dipping is measured and calculated by the following formula.
P = mg + Lγ · cos θ−shρg
(Where P represents the force with which the probe is drawn into the composition, and m, L, s and h are the mass of the probe, the known length, the cross-sectional area, and the probe, respectively, sinking into the composition. (Denote depth, g represents gravitational acceleration, γ represents surface tension, θ represents the contact angle between the probe and the composition, and ρ represents the density of the composition.)

<Light diffusion layer>
The light diffusion layer 55 is disposed on the image light emission side (observer side) of the light control sheet 45. This is for isotropically diffusing the image light emitted from the light control sheet 45.

  The thickness of the light diffusion layer 55 is preferably 0.05 mm to 2.0 mm, and more preferably 0.1 mm to 1.5 mm. This is because if the thickness of the light diffusion layer 55 is less than 0.05 mm, the light diffusion effect may not be sufficiently obtained, and if it exceeds 2.0 mm, the image projected on the transmission screen 10 is blurred. This is because there is a possibility that the video is inferior in resolution.

  The light diffusion layer 55 can be composed of a light transmissive resin containing light diffusion particles. The light diffusing layer 55 isotropically transmits video light, for example, due to a difference in refractive index between the light transmissive resin and the light diffusing particles or due to the reflectivity of the light diffusing particles themselves. Expresses the function of spreading. The image light transmitted through the light control sheet is diffused by the light diffusing ability of the light diffusing layer 55, and the observer can observe the image within the range of the viewing angle corresponding to the light diffusing ability of the light diffusing layer 55. .

  Examples of the light transmissive resin include methyl methacrylate / butadiene / styrene copolymer (MBS), acrylic resin, polycarbonate resin, and polyethylene terephthalate resin.

  As the light diffusing particles, organic fillers such as plastic beads are preferable, and those having high transparency are particularly preferable. Examples of the plastic beads include melamine beads, acrylic beads, acrylic-styrene beads, polycarbonate beads, polyethylene beads, polystyrene beads, and vinyl chloride beads. Among these, acrylic beads are preferable. Further, not only plastic beads but also silicon beads can be used. Furthermore, it is also possible to use plastic beads and silicon beads in combination.

<Surface layer>
The surface layer 60 is a layer provided on the observation surface side from the light diffusion layer 55 and has at least one of a hard coat function, an antiglare function, an antireflection function, an antistatic function, an ultraviolet absorption function, and an antifouling function. It is a layer having. In the present embodiment, the surface layer 60 is a layer having a hard coat function (hard coat layer). The hard coat layer has transparency and exhibits a hardness of “HB” or higher in a pencil hardness test specified by JISK5600-5-4 (1994).

<Transparent Screen Manufacturing Method>
Such a transmission type screen 10 can be manufactured by the following manufacturing method, for example. FIG. 9A to FIG. 11 are diagrams showing manufacturing steps of the transmission screen according to the present embodiment.

First, the Fresnel lens sheet 20 is prepared. The Fresnel lens sheet 20 can be obtained, for example, as follows. That is, an ionizing radiation curable resin composition such as an ultraviolet curable resin composition between a base 21 made of a transparent resin such as an acrylic resin, an epoxy resin, a polycarbonate resin, a polyester resin, and an acrylic-styrene copolymer resin and a mold. The Fresnel lens portion 22 is formed by filling an object and irradiating ionizing radiation to cure the ionizing radiation curable resin composition.
Thereby, the Fresnel lens sheet 20 is produced. And the incident side transparent base material 26 is joined to the image light incident surface of the base portion 21 using a joining layer (not shown) made of an adhesive such as an adhesive or an ultraviolet curable adhesive, and the incident side transparent base material is joined. A Fresnel lens sheet 20 having 26 on the back side is formed (FIG. 9A).

After producing the Fresnel lens sheet 20, the Fresnel lens sheet 20 is heated and softened, for example, so that the Fresnel lens part 22 side is convex, and at least a part of the Fresnel lens sheet 20 has a radius of curvature of 250 mm to 1500 mm. The curved surface is molded so as to have (FIG. 9B).
Specifically, the Fresnel lens sheet 20 is heated and softened to a temperature equal to or higher than the glass transition temperature of the resin constituting the Fresnel lens sheet 20. More specifically, it is softened by heating to 60 to 250 ° C., preferably 70 to 200 ° C.
The softened Fresnel lens sheet 20 is non-contacted by, for example, pressurization using gas pressure on a mold surface (not shown) having a radius of curvature of at least a part of 250 mm to 1500 mm. 20 is pressed, or the Fresnel lens sheet 20 is pressed using a pressing member. During the curved surface molding, the atmosphere between the Fresnel lens sheet 20 and the mold surface is preferably maintained in a reduced pressure state, and more preferably maintained in a vacuum state. Thereby, the Fresnel lens sheet 20 in which at least a part of the Fresnel lens sheet 20 has a curvature radius of 250 mm or more and 1500 mm or less can be obtained.
In the above description, the Fresnel lens sheet 20 is curved so that the Fresnel lens portion 22 side is convex. However, the present invention is not limited to this, and the Fresnel lens portion 22 side is concave, that is, the incident-side transparent base material 26. The Fresnel lens sheet 20 may be curved so that the side is convex, and the Fresnel lens sheet 20 has a shape combining a convex part on the Fresnel lens part 22 side and a concave part on the Fresnel lens part 22 side. 20 may be formed into a curved surface.

  On the other hand, a transparent substrate 35, a light control sheet 45, and a light diffusion layer 55 are prepared. The light control sheet 45 can be produced, for example, by the following method. In other words, the sheet-like base material portion 46 is fed into a mold (not shown) having a plurality of grooves corresponding to the shape of the unit light transmission portion 47, and cured between the mold and the base material portion 46. A composition for a light transmitting part such as an ionizing radiation curable resin composition having an elongation rate in a later state of 15% or more and 50% or less is supplied, and for the light transmitting part between the substrate part 46 and the mold Fill the composition. Thereafter, ionizing radiation is applied to cure the light transmitting portion composition, and the unit light transmitting portion 47 is formed on the substrate portion 46.

After the unit light transmitting portion 47 is formed, the unit light transmitting portion 47 is pulled out from the mold, and an ionizing radiation curable resin composition containing a light absorbing material is inserted into a groove between the plurality of unit light transmitting portions 47. The composition for a light absorption part is filled, and the excess composition is scraped off by a doctor blade or the like.
When the light control sheet 45 is curved so that at least a part of the image light exit surface 45a of the light control sheet 45 has a radius of curvature of 250 mm or more and 1500 mm or less, the elongation percentage after curing is 15. It is preferable to use the composition for light absorption parts which will be 40% or more.
Then, the composition for light absorption parts is hardened by ionizing radiation, and the unit light absorption parts 48 are formed between the unit light transmission parts 47. Thereby, the light control sheet 45 is produced.

  The light diffusion layer 55 can be produced by, for example, extruding a transparent resin containing light diffusion particles into a plate shape using an extrusion molding apparatus. Further, since the transparent resin and the light diffusing particles used in the light diffusion layer 55 have been described above, the description thereof will be omitted.

  And the transparent base material 35 prepared in this way, the light control sheet 45, and the light-diffusion layer 55 are laminated | stacked in this order, and the laminated body 80 is formed (FIG. 10 (a)). When laminating these sheets and layers, the transparent base material 35 and the light control sheet 45, and the light control sheet 45 and the light diffusion layer 55 are made of an adhesive such as an adhesive or an ultraviolet curable adhesive. It joins using the joining layers 40 and 50 which become.

After the laminated body 80 is manufactured, the laminated body 80 is heated and softened so that the light diffusion layer 55 side is convex, and at least a part of the image light emitting surface 45a of the light control sheet 45 is 250 mm or more and 1500 mm or less. The curved surface is molded so as to have a curvature radius of (FIG. 10B).
Specifically, the laminate 80 is heated to the glass transition temperature or higher of the transparent substrate 35 and softened. More specifically, it is softened by heating to 60 to 250 ° C., preferably 80 to 200 ° C. Then, the softened laminate 80 is pressed against the mold surface at least partially having a radius of curvature of 250 mm or more and 1500 mm or less by, for example, pressurization using gas pressure in a non-contact manner, or a pressing member The laminated body 80 is pressed using During this curved surface molding, the atmosphere between the laminate and the mold surface is preferably kept in a reduced pressure state, more preferably in a generally vacuum state. Thereby, the laminated body 80 can be curved-surface molded.

  After the laminate 80 is formed into a curved surface, the surface layer 60 is formed on the light diffusion layer 55 to form the laminate 30 (FIG. 10C). When a hard coat layer is formed as the surface layer 60, a hard coat layer composition containing an ionizing radiation curable resin composition is applied, dried, and cured by ionizing radiation such as ultraviolet rays. As a result, a hard coat layer as the surface layer 60 is formed on the light diffusion layer 55. The hard coat layer may be formed by forming a semi-cured hard coat layer in advance, placing the hard coat layer on the light diffusion layer, and then curing the hard coat layer. It is also possible to form a hard coat layer by applying a thermosetting paint, drying by heating and curing.

  Finally, the curved body-formed laminate 30 is disposed on the image light emitting side of the curved surface-formed Fresnel lens sheet 20 (FIG. 11). In this state, the transparent substrate 35 is on the Fresnel lens portion 22 side of the Fresnel lens sheet 20, and the surface layer 60 is on the observer side. Thereby, the transmission type screen 10 shown in FIG. 1 is completed.

<Rear projection display device>
The transmissive screen 10 can be used by being incorporated in a rear projection display device. As such a rear projection type display device, for example, a rear projection type display device for in-vehicle use or marine use can be cited.

  Hereinafter, a rear projection display device incorporating the transmission screen 10 will be described. FIG. 12 is a schematic cross-sectional view of the rear projection display device according to this embodiment. As shown in FIG. 12, the rear projection display device 70 projects image light onto, for example, the transmissive screen 10, a screen support 71 such as a housing that supports the transmissive screen 10, and the transmissive screen 10. An image light source 72 is provided.

  In the present embodiment, the transmissive screen 10 is supported by the screen support 71 such that the transmissive screen 10 is in the vertical direction. In particular, of the image light exit surface 10a of the transmissive screen 10, the surface orthogonal to the normal direction at the position protruding to the viewer side (corresponding to the central position P of the transmissive screen 10 in the present embodiment) (that is, , The contact surface at the position most protruding to the viewer side) is substantially parallel to the vertical direction.

  The video light source 72 is disposed on the back side of the transmissive screen 10. The image light source 72 shown in FIG. 12 is disposed below the transmissive screen 10 and is configured to project image light onto the transmissive screen 10 without using a mirror or the like. Note that image light may be projected onto the transmissive screen 10 via a mirror or the like.

In this case, in the transmissive screen 10, the extending direction of the unit light transmitting portion 47 and the unit light absorbing portion 48 is the horizontal direction, and the optical center O ₂ of the Fresnel lens portion 22 is the center O _{1 of the} Fresnel lens portion forming surface 20a. It arrange | positions so that it may become the vertical direction lower side.

  In FIG. 12, the image light source 72 is disposed below the transmissive screen 10, but the image light source 72 may be disposed above the transmissive screen 10. In this case, in the transmissive screen 10, the extending direction of the unit light transmitting portion 47 and the unit light absorbing portion 48 is the horizontal direction, and the optical center O2 of the Fresnel lens portion 22 is longer than the center O1 of the Fresnel lens portion forming surface 20a. It arrange | positions so that it may become an upper direction.

  The image light source 72 irradiates the image light on the entire area of the image light incident surface 10 b of the transmissive screen 10 as a divergent light beam (expanded and projected light beam) in which the irradiation region gradually expands. Examples of such an image light source 72 include a known light source, for example, a small light source such as a pico projector using an LED or a laser.

In such a rear projection display device 70, when image light is emitted from the image light source 72, the image light is diverged as shown in FIG. 12, and the entire area of the image light incident surface 10b of the transmissive screen 10 is diverged. Projected on. As shown in FIG. 3, the image light L ₁ projected on the image light incident surface 10 b of the transmissive screen 10 passes through the incident-side transparent base material 26 and enters the Fresnel lens sheet 20. Then, the image light L ₁ is converted into light directed in the front direction N by the Fresnel lens unit 22. The image light L _{1 that} has become light directed in the front direction N enters the light control sheet 45 through the transparent base material 35 and exits from the light control sheet 45 through the unit light transmission portion 47. The image light L ₁ emitted from the light control sheet 45 is diffused by the light diffusion layer 55 and emitted from the image light emission surface 10 a of the transmissive screen 10 via the surface layer 60.
In such a rear projection display device 70, the image light is once converted into light directed in the front direction N by the Fresnel lens sheet 20, and then diffused in the light diffusion layer 55. Therefore, the image displayed from each direction is displayed. When the image is observed, it is possible to provide a high-quality image with reduced in-plane variation in brightness.

Further, not only the image light but also the stray light L ₂ exits from the Fresnel lens sheet 20 and enters the light control sheet 45 as shown in FIG. 3, but the stray light L ₂ is substantially parallel to the front direction N. Therefore, the stray light L ₂ is absorbed by the unit light absorber 48. Further, the outside light L _{3 is} also absorbed by the unit light absorbing portion 48 of the light control sheet 45.

According to this embodiment, the unit light transmission part of the light control sheet is made of a light transmissive resin having an elongation of 15% or more and 50% or less, and the unit light absorption part of the light control sheet contains a light absorbing material. And the resin containing the light absorbing material has an elongation of 15% or more and 40% or less, so that at least a part of the image light exit surface of the light control sheet has a curvature of 250 mm or more and 1500 mm or less. Even when the light control sheet is curved to have a radius, it contains a light-transmitting resin constituting the unit light transmitting portion 47 and a light absorbing material constituting the unit light absorbing portion 48 when the curved surface is molded. By stretching the resin, it is possible to suppress the occurrence of cracks between the unit light transmission part and the unit light absorption part.
Therefore, in the light control sheet according to the present invention, the appearance is not impaired, and a good image can be displayed on the transmissive screen provided with the light control sheet according to the present invention.

  Moreover, according to this embodiment, since the Fresnel lens sheet 20 and the laminated body 30 are curved so as to form a curved surface, the design can be improved without impairing the appearance.

  In addition, according to the present embodiment, since the occurrence of cracks between the unit light transmission part and the unit light absorption part can be suppressed, the yield can be improved and the degree of freedom of the curved surface shape can be improved. be able to.

In addition, when the surface layer 60 is formed on the light diffusion layer 55 before the laminated body 80 is formed into a curved surface, the surface layer 60 may be broken when the laminated body 80 is formed into a curved surface.
On the other hand, in the present embodiment, since the surface layer 60 is formed on the light diffusion layer 55 after the laminate 80 is formed into a curved surface, the surface layer 60 can be prevented from cracking.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described. In this embodiment, an example in which a transmission screen is manufactured by a method different from that of the first embodiment will be described. FIG. 13A to FIG. 13C are diagrams schematically showing a manufacturing process of the transmission screen according to the second embodiment.

  First, as in the first embodiment, a Fresnel lens sheet 20 having an incident side transparent base material 26 on the back side is prepared. Moreover, the transparent base material 35, the light control sheet 45, and the light-diffusion layer 55 are prepared similarly to 1st Embodiment, These are laminated | stacked in this order, and the laminated body 80 is formed.

  Thereafter, the Fresnel lens sheet 20 and the laminated body 80 are laminated so that the laminated body 80 is disposed on the image light emitting side of the Fresnel lens sheet 20 (FIG. 13A). In the laminated state, the transparent base material 35 is on the Fresnel lens portion 22 side of the Fresnel lens sheet 20, and the light diffusion layer 55 of the laminated body 80 is on the observer side.

  After the Fresnel lens sheet 20 and the laminated body 80 are laminated, they are heated and softened so that the light diffusion layer 55 side is convex, and at least a part of the image light emitting surface 45a of the light control sheet 45 is formed. The Fresnel lens sheet 20 and the laminate 80 are formed into a curved surface so as to have a curvature radius of 250 mm or more and 1500 mm or less (FIG. 13B).

  After the Fresnel lens sheet 20 and the laminate 80 are formed into a curved surface, the surface layer 60 is formed on the light diffusion layer 55 to form the laminate 30 (FIG. 13C). Thereby, the transmission type screen 10 shown in FIG. 1 is completed.

(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described. In the present embodiment, an example in which a transmission screen is incorporated in a rear projection display device having a touch panel function will be described. FIG. 14 is a schematic cross-sectional view of a rear projection display device having a touch panel function according to the present embodiment, and FIG. 15 is a view of the rear projection display device having a touch panel function according to the present embodiment as viewed from above. is there. In FIG. 14 and FIG. 15, members and the like having the same reference numerals as those in the first embodiment are the same as the members and the like described in the first embodiment, and thus description thereof is omitted. .

  As shown in FIG. 14, the rear projection display device 90 includes, for example, a transmissive screen 10, a screen support 71 that supports the transmissive screen 10 such as a housing, and an image that projects image light on the transmissive screen 10. A light source 72 is provided. Further, as shown in FIGS. 14 and 15, the rear projection display device 90 includes an infrared light source 91 that projects infrared light onto the transmissive screen 10, a CCD camera that can detect infrared light, and the like. An infrared light detector 92 and the like are provided. The infrared light source 91 and the infrared light detector 92 are disposed on the back side of the transmissive screen 10.

  Infrared light emitted from the infrared light source 91 passes through the transmissive screen 10. Thereby, for example, when a finger or a dedicated pen touches the transmissive screen 10, infrared light is reflected by the finger or the like, so that the finger position information can be detected by the infrared light detector 92. it can. Thereby, a touch panel function is realizable.

  Note that the present invention is not limited to the description of the above embodiment, and the structure, material, arrangement of each member, and the like can be changed as appropriate without departing from the gist of the present invention.

  In order to describe the present invention in detail, the following examples will be described.

(Example)
First, a Fresnel lens sheet was prepared. As the incident side transparent base material of the Fresnel lens sheet, an acrylic plate having a thickness of 1.3 mm was used. The Fresnel lens portion of the Fresnel lens sheet was made of a cured product of an ultraviolet curable resin composition containing urethane acrylate, and the unit prism pitch was 105 μm.

  The Fresnel lens sheet was heated to 80 ° C. to be softened and curved-surface molded by vacuum molding. In addition, curved surface shaping | molding was performed so that a curvature radius might be set to 1000 mm.

  On the other hand, a transparent substrate, a light control sheet, and a light diffusion layer were prepared. As the transparent substrate, an acrylic plate having a thickness of 3 mm was used.

  As the light control sheet, a unit having a unit light transmission part and a unit light absorption part formed on a polycarbonate (PC) film and having a thickness of 0.3 mm was used.

The light transmissive resin constituting the unit light transmissive part has an elongation of 42.4%, and the resin containing colored particles as the light absorbing material constituting the unit light absorbing part contains colored particles. In this state, it had an elongation of 30.5%.
Further, the resin containing colored particles as a light absorbing material constituting the unit light absorbing portion had a viscosity of 2000 mPa · s in a state containing colored particles.

  Further, the surface tension of the light transmitting resin constituting the unit light transmitting portion is 36 mN / m, and the resin containing the colored particles as the light absorbing material constituting the unit light absorbing portion contains the colored particles. The surface tension was 30 mN / m.

  Moreover, the refractive index of the unit light transmission part was 1.550, and the refractive index of the unit light absorption part was 1.490. The height of the unit light absorption part was 150 μm. The width of the unit light absorbing part is 30 μm at the image light emitting surface, the width of the tip part on the image light incident side in the unit light absorbing part is 6 μm, and the pitch of the bottom part on the image light emitting side in the unit light absorbing part is 60 μm. Met. Furthermore, the angle formed by the normal line of the polycarbonate film and the unit light absorbing portion was 4.5 °.

Specifically, the light control sheet was produced as follows.
First, a sheet-like polycarbonate film is fed into a mold having a plurality of grooves corresponding to the shape of the unit light transmission part, and in a state after curing including urethane acrylate between the mold and the polycarbonate film. An ultraviolet curable resin composition having an elongation of 42.4% was supplied, and the ultraviolet curable resin composition was filled between the polycarbonate and the mold.
Thereafter, ultraviolet rays were irradiated to cure the ultraviolet curable resin composition, thereby forming unit light transmitting portions made of a light transmitting resin on the polycarbonate.
After forming the unit light transmission part, the unit light transmission part is pulled out from the mold, and subsequently, an ultraviolet curable resin composition containing urethane acrylate containing colored particles or the like in grooves between the plurality of unit light transmission parts. Filled and surplus composition was scraped off by doctor blade.
The ultraviolet curable resin composition contained 3% colored particles, and the elongation percentage after curing was 30.5%. Thereafter, the ultraviolet curable resin composition was cured with ultraviolet rays to form unit light absorbing portions made of a resin containing colored particles between the unit light transmitting portions.

  As a light diffusion layer, methyl methacrylate / butadiene / styrene copolymer (MBS) resin having a refractive index of 1.550, acrylic beads having a refractive index of 1.500 and an average particle size of 10 μm as light diffusion particles, It was made of a material containing silicon beads having a ratio of 1.420 and an average particle diameter of 2 μm, and a thickness of 0.14 mm was used. The proportion of each component of the light diffusion layer was 50% by weight of methyl methacrylate / butadiene / styrene copolymer resin, 40% by weight of acrylic beads, and 10% by weight of silicon beads.

  After preparing a transparent base material etc., the transparent base material, the light control sheet | seat, and the light-diffusion layer were laminated | stacked in this order, and the laminated body was formed. Here, when laminating a transparent base material or the like, the transparent base material and the light control sheet, and the light control sheet and the light diffusion layer were bonded with an ultraviolet curable adhesive.

  The laminate was heated to 140 ° C. to be softened and curved-surface molded by vacuum molding using a mold. The curved surface was formed so that the radius of curvature of the image light exit surface of the light control sheet was 1000 mm.

  After the laminate was formed into a curved surface, an acrylic urethane thermosetting paint was applied to the surface of the laminate and dried by heating, and then a hard coat layer was formed. Finally, the laminate was placed on the image light exit side of the Fresnel lens sheet to produce a transmission screen according to the present invention.

(Evaluation of fillability)
The filling property of the ultraviolet curable resin composition containing the colored particles into the grooves between the plurality of unit light transmission portions in the light control sheet of the transmission type screen prepared above was evaluated.
Here, the filling property is evaluated by observing the cut surface of the produced light control sheet with a scanning electron microscope (SEM), and the unit light-absorbing part (the composition containing the colored particles is actually used for the cross-sectional area of the groove). The ratio of the area of the portion filled in was evaluated as the filling rate.

  As a result, in the light control sheet according to the present invention, the resin constituting the unit light transmitting portion (light transmitting resin) and the resin constituting the unit light absorbing portion (resin containing colored particles) are as described above. Even when a high elongation rate was given, the filling rate of the resin constituting the unit light absorbing portion into the groove between the plurality of unit light transmitting portions was as high as 98% or more.

(Presence of cracks)
Further, using the transmission type screen produced above, a durability test was conducted by leaving it in an environment of 95 ° C. for one week, and it was evaluated whether or not a crack occurred in the light control sheet of the transmission type screen after the test. . In addition, the judgment whether the crack has arisen was performed by observing the cut surface of the produced light control sheet using the scanning electron microscope (SEM).
As a result, it was confirmed that the light control sheet of the transmissive screen according to the present invention had no cracks generated between the unit light transmission part and the unit light absorption part even after one week had passed after being left.

DESCRIPTION OF SYMBOLS 10 ... Transmission type screen 10a ... Image | video light emission surface 10b ... Image | video light incident surface 20 ... Fresnel lens sheet 20a ... Fresnel lens part formation surface 21 ... Base 22 ... Fresnel lens Unit 23 ... Unit prism 26 ... Incident side transparent base material 30 ... Laminate 35 ... Transparent base material 45 ... Light control sheet 45a ... Image light exit surface 45b ... Image light Incident surface 46 ... base material part 47 ... unit light transmission part 48 ... unit light absorption part 55 ... light diffusion layer 60 ... surface layer 70, 90 ... rear projection type display device 72 ... Image light source 80 ... Laminated body 91 ... Infrared light source 92 ... Infrared light detector

Claims (10)

A light control sheet used for a transmissive screen that transmits image light projected from an image light source and emits the image light to an observer side,
The light control sheet is bent so that at least a part of the image light exit surface has a curvature radius of 250 mm or more and 1500 mm or less,
A plurality of unit light transmitting portions constituting a part of the image light emitting surface;
A plurality of unit light absorbing portions that constitute a part of the image light emitting surface and are alternately arranged with the unit light transmitting portions and have a height of 80 μm or more and 150 μm or less;
With
The unit light transmitting portion is made of a light transmitting resin having an elongation of 15% or more and 50% or less,
The unit light absorbing portion is made of a resin containing a light absorbing material,
The light control sheet, wherein the resin containing the light absorbing material has an elongation of 15% or more and 40% or less and a viscosity of 1700 mPa · s or more and 3500 mPa · s or less.   2. The light according to claim 1, wherein a surface tension of a resin containing a light absorbing material constituting the unit light absorbing portion is smaller than a surface tension of a light transmitting resin constituting the unit light transmitting portion. Control sheet. A transmissive screen that transmits image light projected from an image light source and emits the image light to an observer side,
A laminate comprising the light control sheet according to claim 1 or 2 and a light diffusion layer disposed on the image light emission side of the light control sheet,
A transmissive screen, wherein the entire laminate is curved so as to form a curved surface.   The transmissive screen according to claim 3, wherein the entire laminate is bent so as to form a three-dimensional curved surface.   The Fresnel lens sheet which has a Fresnel lens part arrange | positioned rather than the said laminated body at the said image light source side is further provided, The said Fresnel lens sheet is curved so that a curved surface may be made. 4. The transmission screen according to 4.   6. The transmission screen according to claim 5, wherein the unit light transmission part and the unit light absorption part extend in a lateral direction of the transmission screen.   6. The optical center according to claim 5, wherein the Fresnel lens part has an optical center at a position decentered downward in the longitudinal direction of the transmission screen with respect to the center of the Fresnel lens part forming surface of the Fresnel lens sheet. Transmission screen.   The unit light transmitting portion and the unit light absorbing portion are substantially parallel to a direction connecting the center of the Fresnel lens portion forming surface and the optical center of the Fresnel lens portion, and are arranged along the image light emitting surface. 6. The apparatus according to claim 5, wherein the first light source is arranged alternately in the first direction, is substantially orthogonal to the first direction, and extends in a second direction along the image light exit surface. A transmissive screen according to 1.   A transmission screen according to any one of claims 3 to 8, and a video light source disposed on the back side of the transmission screen and projecting video light onto the transmission screen. A rear projection display device. The rear projection display device according to claim 9, further comprising: an infrared light source that projects infrared light on the transmissive screen; and an infrared light detector capable of detecting the infrared light. .

Images