JP2007178501A - Transmissive type screen and projection type display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmissive type screen and a projection type display, in which warp of a screen is easily restrained even in the environment where temperature and humidity change. <P>SOLUTION: The transmissive type screen 20 is composed of a Fesnel lens sheet 30 and a lenticular lens sheet 40. The lenticular lens sheet 40 is formed from, in the direction of thickness: a lens substrate 42; a main substrate 60; a surface substrate 61; adhesive layers 46 joining the adjacent substrates; a first diffusion layer 49; cylindrical lenses 43 formed on the surfaces of the lens substrate 42 and surface substrate 61; and a surface coat layer 51. The lens substrate 42, main substrate 60, and surface substrate 61 are arranged so that they may be almost symmetrical in the direction of the thickness of the lenticular lens sheet 40 in terms of expansion characteristic value, flexural rigidity, and disposed position. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transmissive screen and a projection display.

Conventionally, a rear projection television is known as a projection display provided with a transmissive screen. In recent years, MD-type projection televisions have emerged as opposed to thin large-sized displays such as liquid crystal displays (LCDs) and plasma displays (PDPs). An MD projection television, for example, projects projection light modulated using a display device such as an LCD, LCOS (LCD on Silicon; a type of reflective liquid crystal panel), or a digital micromirror device (DMD) from the rear side of the transmissive screen. Projected.
This MD projection television can easily be increased in size to 40 inches or more, has a good image quality because of digital display, and can be manufactured at a relatively low cost. Has been.

A transmissive screen used for such a projection display as an MD projection television is composed of a Fresnel lens sheet that adjusts the direction of incident light and emits it as substantially parallel light, and a Fresnel lens sheet to provide an appropriate viewing angle. Lenticular lens sheet that diffuses the emitted light from, for example, a cylindrical lens group arranged in the horizontal and vertical directions (not limited to the configuration in which the cylindrical lens groups are arranged in one direction, but the cylindrical lens groups are arranged in a plurality of directions) And various types of light diffusing lens array sheets, such as a structure in which unit lenses are two-dimensionally arranged.
A diffusion layer for diffusing transmitted light is provided in the Fresnel lens sheet and the lenticular lens sheet in order to reduce luminance unevenness and scintillation.
For example, Patent Document 1 discloses a lenticular sheet used for a transmission screen, in which a lens portion in which convex cylindrical lenses are arranged on one side of a transparent support is formed of a cured product of a radiation curable resin. The light-shielding pattern and the diffusion layer are formed on the surface by film transfer or film lamination, and a film having an antistatic function and an antireflection function is further provided on the diffusion layer.
JP-A-9-120101 (FIG. 1)

However, the conventional transmissive screen as described above and the projection display using them have the following problems.
In the technique described in Patent Document 1, since a lenticular sheet is configured by laminating film layers having different functions on a transparent support, the thickness of each layer, the linear expansion coefficient of each layer material, the moisture swelling coefficient, etc. Because of this difference, there is a problem that warping occurs when temperature or humidity varies.
Therefore, when it is used for a transmission type screen, the Fresnel lens sheet 90 and the Fresnel lens sheet 91 warp as shown by a broken line in a high-temperature and high-humidity environment, for example, as shown in a schematic cross-sectional view in FIG. , Each may swell outside the screen. In this case, the Fresnel lens sheet 90 and the Fresnel lens sheet 91 are separated from each other at the center of the screen. When such a so-called screen floating phenomenon occurs, there is a problem in that the optical path length of the screen changes, resulting in poor resolution, image blur, and the like, thereby degrading the image quality. Therefore, for example, there is a problem that it becomes unsuitable for full HDTV (High Definition Television) in which high definition such as a horizontal resolution of 1080 pixels is required.
For example, increasing the thickness of the transparent support of the lenticular sheet to increase the rigidity or using a highly rigid material such as glass can reduce the warpage, but recent transmission screens have become larger. Since high definition is required, it is difficult to cope with this direction.
Therefore, for example, as shown in FIG. 7B, the Fresnel lens sheet 90 and the lenticular sheet 91 are manufactured by giving initial warpage in which the bulging directions oppose each other as shown by a two-dot chain line, When the screen is constructed by holding it together, it may be possible to suppress each other even if warpage occurs due to environmental changes by performing warping so that it is corrected to a flat state as shown by the solid line. It is done.
In this case, although it is possible to prevent warping due to environmental changes, there is a problem that both the sheets must be warped with an appropriate balance, which requires time for manufacturing and increases manufacturing costs. In particular, since the lenticular sheet has a complicated multilayer structure including a lens portion, a BS layer, a diffusion layer, a hard coat layer, and the like, it is preferably manufactured in a planar state.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a transmissive screen and a projection display that can easily suppress warping of the screen even in an environment where temperature and humidity change. And

In order to solve the above-described problems, in the invention described in claim 1, the Fresnel lens sheet that makes the projection light projected from the light source substantially parallel light, and the projection light that is made substantially parallel light by the Fresnel lens sheet A transmissive screen having a light diffusing lens array sheet that diverges, wherein the light diffusing lens array sheet includes a plurality of laminated substrates having light transmittance arranged in a thickness direction thereof, and the plurality of laminated substrates. Among them, a bonding layer for bonding adjacent ones and a surface layer formed on the surface of the laminated substrate located at the outermost part in the thickness direction, the plurality of laminated substrates have an expansion characteristic value and a bending rigidity. And the arrangement position is arranged so as to have substantially symmetry in the thickness direction.
According to the present invention, the plurality of laminated substrates are arranged so as to have substantially symmetry in the thickness direction at the expansion characteristic value, the bending rigidity, and the arrangement position. When stress is generated by expansion and contraction, a stress distribution is formed such that bending moments substantially cancel each other due to the symmetry. As a result, warpage deformation can be suppressed.
Here, the expansion characteristic value is a characteristic value that governs the expansion and contraction of the laminated substrate when temperature and humidity change, and means at least one of a linear expansion coefficient and a moisture swelling coefficient. In order to suppress warpage deformation in an environment where both temperature and humidity vary, it is preferable to arrange the linear expansion coefficient and the moisture swelling coefficient so that the values are substantially symmetrical.
However, when one of the expansion characteristic values is substantially governed by the expansion and contraction of the laminated substrate in the temperature and humidity change ranges where warpage deformation should be suppressed, for example, the moisture swelling coefficient is sufficiently smaller than the linear expansion coefficient. In some cases, only one of the expansion characteristic values may be arranged substantially symmetrically.
In addition, as the bending rigidity in the present specification, a physical property value that almost controls warping deformation can be adopted. That is, it is not necessary to consider the bending rigidity of the plate including the Poisson's ratio, and it is sufficient to consider the bending rigidity of the beam having a unit width in the vertical or horizontal cross section of the light transmission portion. Therefore, arranging the bending rigidity symmetrically means arranging the products of the longitudinal elastic modulus and the cube of the plate thickness symmetrically.

According to a second aspect of the present invention, in the transmissive screen according to the first aspect, each pair of the multilayer substrates having substantially symmetry among the plurality of multilayer substrates is made of a substrate having the same material and the same thickness. It becomes the composition which becomes.
According to this invention, each pair of laminated substrates having substantially symmetry is made of the same material and the same thickness, so that the longitudinal elastic modulus and the plate thickness are the same, the bending rigidity is the same, and the bending is the same. Accurate symmetry with respect to rigid placement is obtained.

According to a third aspect of the present invention, in the transmissive screen according to the first or second aspect, the plurality of multilayer substrates have an odd number of configurations, and the center in the thickness direction among the plurality of multilayer substrates. And the pair of peripheral substrates arranged on the peripheral side in the thickness direction are made of different materials.
According to the present invention, since the pair of the central substrate and the peripheral substrate is made of different materials, the structure utilizing the characteristics of each material can be obtained.
For example, if the peripheral substrate that forms the lens portion as the surface layer is a relatively thin plate having flexibility, it is convenient for demolding when the lens portion is molded, while the central substrate is high. If the plate has a relatively thick plate shape, the rigidity as the light diffusion lens array sheet can be secured.
Further, the optical path length can be changed by changing each material, and the arrangement of the laminated substrates can be made symmetric while ensuring the required optical path length.

According to a fourth aspect of the present invention, in the transmissive screen according to any one of the first to third aspects, the bonding layer has a light diffusibility by dispersing a light diffusing material in a light transmissive adhesive. It is set as the structure which is a diffusion adhesion layer.
According to this invention, since the bonding layer can be used also as the diffusion layer by the diffusion adhesive layer, a simple configuration can be obtained.

In a fifth aspect of the present invention, the projection display includes the transmissive screen according to any one of the first to fifth aspects.
According to this invention, since the transmissive screen according to any one of claims 1 to 4 is provided, the same effect as the invention according to any one of claims 1 to 4 is provided.

  According to the transmissive screen and the projection display of the present invention, the light diffusing lens array sheet is configured by using a plurality of laminated substrates, and the laminated substrates are substantially symmetrical in terms of expansion characteristic values, bending rigidity, and arrangement positions. Therefore, even if the light diffusing lens array sheet is manufactured in a flat state, it is possible to easily suppress the warpage of the screen.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
A transmissive screen and a projection display according to the first embodiment of the present invention will be described.
FIG. 1 is a schematic explanatory view in a cross section including an optical axis of a projection optical system for explaining a projection display according to the first embodiment of the present invention. FIG. 2 is a cross-sectional explanatory view taken along the direction perpendicular to the plane of FIG. 1 for explaining the schematic configuration of the transmission screen according to the first embodiment of the present invention. FIG. 3 is a partially enlarged view of FIG. 2 schematically illustrating the detailed configuration of the transmissive screen according to the first embodiment of the present invention. Note that these drawings are schematic diagrams, and the shapes and dimensions are exaggerated (the same applies to the following).

As shown in FIG. 1, the rear projection television 10 (projection display) of the present embodiment exposes the casing 11 and the front side (right side in FIG. 1) to the outside of the casing 11 and the rear side (FIG. 1). As a light source for projecting projection light to the rear surface of the transmissive screen 20. The transmissive screen 20 has a substantially rectangular flat plate shape with the left side exposed to the inside of the housing 11. The projector 12 is also provided in the housing 11 and includes, for example, two reflecting mirrors 13 and 14 that deflect the optical path of the projection light projected from the projector 12.
As the projector 12, an appropriate projector can be adopted. For example, a display device such as an LCD, an LCOS (LCD on Silicon), a DMD (digital micromirror device), or the like is used. Thus, an MD projector that projects the modulated projection light from the rear side of the transmissive screen can be suitably employed.
In the following, for convenience of referring to the direction, the vertical direction of FIG. 1 is changed to the vertical direction (vertical direction) of the screen based on the normal arrangement posture of the rear projection television 10 and the viewing posture of the viewer, and FIG. The direction perpendicular to the paper surface may be referred to as the left-right direction (horizontal direction) of the screen.

Here, when there is no deflection by the reflecting mirrors 13 and 14, the arrangement position of the projector 12 is optically equivalent to the position of the two-dot chain line in FIG. 1, and in the following, unless otherwise specified. A description will be given based on an appropriate optical arrangement.
That is, the optical axis P1 of the transmissive screen 20 that coincides with the lens optical axis of the Fresnel lens sheet 30 to be described later is in a position translated downward from the center P2 of the transmissive screen 20, and the projector 12 has the optical axis P1. On the upper side, the transmissive screen 20 is disposed at a predetermined distance from the incident surface to the back side (left side in FIG. 1).

As shown in FIG. 2, the transmissive screen 20 includes a Fresnel lens sheet 30 having a Fresnel lens portion 31 that adjusts the direction of incident light to be emitted, and the emitted light from the Fresnel lens sheet 30 in the horizontal direction of the screen. And a lenticular lens sheet 40 (light diffusion lens array sheet) that is an optical member having a lens portion 44 that diffuses in the vertical direction (the vertical direction in FIG. 2) and the vertical direction (the vertical direction in FIG. 2).
The Fresnel lens sheet 30 and the lenticular lens sheet 40 are sequentially arranged from the rear side (left side in FIG. 2) to the front side (right side in FIG. 2) of the transmissive screen 20, and are also substantially parallel to each other. . In the following, the Fresnel lens sheet 30 side direction will be referred to as the light source side direction and the lenticular lens sheet 40 side direction will be referred to as the observation side direction, respectively. That is, in the present embodiment, the projection light is transmitted from the light source side toward the observation side.
Here, since FIG. 2 is a schematic diagram, the Fresnel lens portion 31 and the lens portion 44 are drawn so as to be separated from each other. However, if they are separated too much, the image will be blurred. It is preferable to have a configuration that can be in contact with each other and supported.

  As shown in FIG. 2, the Fresnel lens sheet 30 includes a third diffusion layer 33, a substrate portion 32, and a Fresnel lens portion 31 sequentially arranged from the incident light incident side, and the third diffusion layer 33, the Fresnel lens portion 31, and the like. However, it is bonded to the front and back bonding surfaces of the substrate portion 32. The Fresnel lens portion 31 is disposed to face the lenticular lens sheet 40.

The third diffusion layer 33 is for diffusing light while transmitting incident projection light. For example, a light diffusion layer or a light diffusion member formed in a layer shape, a plate shape, or a sheet shape having light diffusibility is employed. be able to. In this embodiment, as shown in FIG. 3, for example, a resin in which a filler 33b (light diffusing material) having a refractive index different from that of the base material 33a is dispersed inside a transparent base material 33a (light diffusing base material). Are stacked on the substrate portion 32.
In the present embodiment, the thickness of the third diffusion layer 33 is 50 μm to 300 μm, and the diffusion degree H ₃₃ is a haze value and is set to a value of 50% to 70%.
As a material of the base material 33a, an appropriate transparent resin can be adopted, and for example, methyl methacrylate-styrene copolymer resin (MS resin) can be suitably adopted. For example, MS resin containing 60% of methyl methacrylate (MMA) and n _33a = 1.53 can be used.
As a material of the filler 33b, an appropriate filler having a refractive index different from that of the base material 33a can be employed. For example, an organic filler having an average particle size of 10 μm and n _33b = 1.50 can be suitably used. The difference in refractive index between the base material 33a and the filler 33b is preferably in the range of 0.03 to 0.10. Therefore, for example, an MS filler of n _33a = 1.57 can be used as the base material 33a, and an organic filler of n _33b = 1.47 can be used as the filler 33b.

Note that light diffusion includes internal diffusion caused by a light diffusing material inside the diffusion layer and external diffusion caused by irregularities on the incident and exit surfaces of the diffusion layer. The unevenness of the incident / exit surface includes, for example, unevenness intentionally formed by mat processing or the like, and unevenness formed by exposing the light diffusing material from the base material.
In order to reduce scintillation, both internal diffusion and external diffusion are effective. Therefore, the diffusion layer according to this embodiment has a configuration in which appropriate irregularities are provided on the incident / exit surface in order to achieve a necessary degree of diffusion. It is good.
The unevenness level due to exposure of the light diffusing material can be controlled by using a mixture of a spherical material such as an organic filler and an irregular shape such as an inorganic filler as the light diffusing material. For example, instead of the filler 33b, a mixture of organic resin beads and inorganic fillers such as talc and glass beads at an appropriate blending ratio may be used.

The substrate part 32 is a light-transmitting flat plate for supporting the Fresnel lens part 31. And the Fresnel lens part 31 is formed in the back surface side of the surface in which the 3rd diffused layer 33 was formed.
The material of the substrate part 32 may be any material as long as it is a transparent plate member. For example, MS resin or the like can be suitably used. A substrate such as glass can also be employed.

The Fresnel lens portion 31 is formed in a substantially serrated shape whose cross section including the optical axis is symmetric with respect to the optical axis. When viewed from the optical axis direction, the Fresnel lens portion 31 is arranged concentrically around the optical axis P1 (see FIG. 2). , Which forms a ring zone.
The sawtooth lens surface is composed of, for example, a lens surface such as a spherical surface or an aspherical surface that forms part of a convex lens, and a substantially cylindrical surface along the optical axis P1, depending on design conditions, and is arranged at the focal position. The projection light emitted from can be made substantially parallel light.
In the present embodiment, the thickness of the Fresnel lens portion 31 is formed to be about 50 μm to 70 μm at the peripheral portion. It is set as the structure which becomes thinner than it in the center part.

The Fresnel lens sheet 30 can be manufactured, for example, as follows.
First, for example, an ultraviolet curable resin is supplied to a mold for forming the shape of the Fresnel lens portion 31. Then, the substrate portion 32 having the third diffusion layer 33 formed on one surface is disposed so that the other surface is in close contact with the ultraviolet curable resin, and the substrate portion 32 is pressed by, for example, a roller as necessary. Drain excess UV curable resin. In this state, ultraviolet rays are irradiated from the UV illumination light source through the substrate portion 32 to cure the ultraviolet curable resin. Then, after the ultraviolet curable resin is cured, the mold is removed from the mold. In this way, the Fresnel lens part 31 to which the shape of the mold is transferred is formed on the substrate part 32.
The Fresnel lens sheet 30 can be kept in a flat state by warping on the side in contact with the lenticular lens sheet 40 or by using a highly rigid resin material or a glass substrate for the substrate portion 32. deep.

Next, the lenticular lens sheet 40 will be described.
As shown in FIG. 3, the lenticular lens sheet 40 includes a lens portion 44 (surface layer), a lens substrate 42 (laminated substrate), a black stripe (BS) layer 45, an adhesive layer 46 (bonding layer) from the Fresnel lens sheet 30 side. ), The second diffusion layer 48, the main substrate 60 (laminated substrate), the first diffusion layer 49 (bonding layer), the surface substrate 61 (laminated substrate), and the surface coat layer 51 (surface layer) are arranged in layers in this order. It is a flat plate member that is attached in a state of maintaining a flat surface without being bent by giving an initial deformation or the like during assembly. The shape viewed from the optical axis direction is a substantially rectangular shape similar to the outer shape of the Fresnel lens sheet 30.

The lens unit 44 includes a plurality of cylindrical lenses 43 having a substantially semi-cylindrical shape arranged in parallel with each other and extended in the vertical direction (vertical direction, vertical direction in the drawing), and the incident surface of the lenticular lens sheet 40. Is configured.
With such a configuration, the projection light emitted from the Fresnel lens sheet 30 is collected in the horizontal direction (horizontal direction, vertical direction in the drawing) of the screen, and then emitted toward the second diffusion layer 48 while diffusing in the horizontal direction. It can be done.

The lens substrate 42 is a light-transmitting substrate having a thickness t ₁ provided to support the cylindrical lens 43. In the present embodiment, it is made of polyethylene terephthalate (PET) resin, and t ₁ = 75 μm. The material properties of the PET resin include, for example, a linear expansion coefficient of 1.5 × 10 ⁻⁵ (cm / cm / ° C.), a moisture swelling coefficient of 1.2 × 10 ⁻⁵ (1 /% RH), and a tensile elastic modulus. A material having a (longitudinal elastic modulus) of 3920 MPa (400 kgf / mm ² ) can be employed.

  The lens portion 44 having such a configuration can be manufactured in the same manner as the Fresnel lens sheet 30, for example. That is, a mold for molding the cylindrical lens 43 is used corresponding to the mold for molding the lens unit 44, and the cylindrical lens 43 and the lens substrate 42 are made to correspond to the Fresnel lens unit 31 and the substrate unit 32. It can manufacture with said manufacturing method.

The BS layer 45 extends in a stripe shape along the generatrix direction of the cylindrical lens 43 on the back surface side of the lens substrate 42 provided with a plurality of cylindrical lenses 43 on the front surface. A black stripe that is shielded in a stripe shape by an appropriate range is formed by a light absorption band. Between each BS layer 45, a light-transmitting adhesive layer 46 that also serves as an adhesive layer for bonding the second diffusion layer 48 is provided. Since the adhesive layer 46 is formed as a thin layer, the BS layer 45 and the second diffusion layer 48 are provided in close proximity to each other. The focal position of the cylindrical lens 43 is set in the range where the vignetting by the BS layer 45 does not occur, or in the vicinity of the boundary of the light transmitting portion 47 or the boundary surface where the light transmitting portion 47 and the second diffusion layer 48 are in contact.
Therefore, the projection light collected by the cylindrical lens 43 is imaged in the light transmission part 47 or in the vicinity of the boundary surface between the light transmission part 47 and the second diffusion layer 48, and then propagates as diverging light. It proceeds toward the second diffusion layer 48.
In the present embodiment, the thickness of the adhesive layer 46 is about 50 μm including the BS layer 45.

  The second diffusion layer 48 is for diffusing the projection light transmitted through the light transmission portion 47 in the vicinity of the focal position before being diffused by the first diffusion layer 49. In the present embodiment, as shown in FIG. 3, for example, a filler 48 b (light diffusion) having a refractive index different from that of the base material 48 a inside the transparent base material 48 a (light diffusion base material) is formed on the surface of the main substrate 60. The resin in which the material is dispersed is formed to a thickness t by lamination or coating by coextrusion. Therefore, diffusion of the projection light transmitted through the light transmitting portion 47 starts from the boundary surface with the light transmitting portion 47, and the diffusion proceeds within the thickness t.

Diffusion degree _{H 48} of the second diffusion layer 48 and the third diffusion layer 33, less than the diffusion degree _{H 33, H 49} in the first diffusion layer 49, the refractive index difference between the substrate 48a and the filler 48b, the third diffusion layer The refractive index difference is set to be smaller than the refractive index difference between the 33 base material 33a and the filler 33b and substantially equal to the refractive index difference between the base material 49a and the filler 49b of the first diffusion layer 49.
In the present embodiment, for example, the thickness t = 100 μm. The diffusion degree _H48 is a haze value and is preferably 10% to 30%. For example, the diffusion degree H48 is set to _H48 = 20%.
As a material of the base material 48a, an appropriate transparent resin or the like can be used, and for example, an MS resin can be preferably used. For example, a material of n _48a = 1.53 can be used for MS resin containing 60% MMA.
As a material of the filler 48b, an appropriate filler having a refractive index different from that of the base material 48a can be employed. For example, an organic filler having an average particle size of 10 μm and n _48b = 1.55 can be suitably used.

The main substrate 60 is a transparent substrate provided with a relatively thick thickness t _{0 such} that t ₀ > t ₁ in order to play the main part of the rigidity of the lenticular lens sheet 40. In this embodiment, it is made of polycarbonate (PC) resin with t ₀ = 0.5 mm. The material properties of the PC resin include, for example, a linear expansion coefficient of 7 × 10 ⁻⁵ (cm / cm / ° C.), a moisture absorption rate of 0.20% or less, and a tensile elastic modulus of 3097 MPa (31600 kgf / cm ² ). Things can be adopted.

The first diffusion layer 49 is the diffusion layer provided on the most observation side of the lenticular lens sheet 40, formed on the observation side surface of the main substrate 60, and diffused in the horizontal and vertical directions by the second diffusion layer 48. It is provided for diffusing the projection light in the range of the required viewing angle.
In order to reduce scintillation, the interlayer distance between the third diffusion layer 33 and the first diffusion layer 49 is preferably set to 1 mm or more.
In the present embodiment, for example, a diffusion adhesive layer in which a filler 49b (light diffusing material) having a refractive index different from that of the base material 49a is dispersed inside an adhesive transparent base material 49a (light diffusing base material). It is laminated on the main substrate 60.

In order to form such a diffusion adhesive layer, for example, an active energy ray-curable resin that has adhesiveness as the base material 49a and cures when exposed to active energy rays (for example, ultraviolet rays) and exhibits adhesiveness. A transfer sheet in which a filler 49b is mixed to form a layer having an appropriate thickness is formed between release films. As the release film, a PET film that has been subjected to surface treatment (release treatment) such as fluorine treatment or silicon treatment can be employed as necessary.
As the active energy ray curable resin, for example, an ultraviolet curable photopolymer is used, and specifically, a known adhesive containing an acrylic polymer, an acrylic monomer, a photoinitiator, and the like is used.

Then, before the first diffusion layer 49 is cured, one of the release films is peeled off, and the surface on which the first diffusion layer 49 is exposed is, for example, the surface of either the main substrate 60 or the surface substrate 61 using a roll or the like. Adhere it in close contact. At this time, if the first diffusion layer 49 has adhesiveness at room temperature, the first diffusion layer 49 is stuck to the main substrate 60 or the surface substrate 61 as it is. In addition, when the first diffusion layer 49 has adhesiveness by heating, the roll is heated so that the first diffusion layer 49 exhibits adhesiveness and is attached. Next, the other part of the release film is peeled off and adhered to either the main substrate 60 or the front substrate 61 in the same manner.
Then, the active energy ray is irradiated to the first diffusion layer 49 through the main substrate 60 or the surface substrate 61. As a result, the first diffusion layer 49 is cured, and the main substrate 60 and the front substrate 61 are bonded.

The diffusion degree H ₄₉ of the first diffusion layer 49 of the present embodiment is a haze value and is set to a value of 70% to 90%. The magnitude of the diffusion degree can be set in the above range in the same manner as the third diffusion layer 33. For example, H ₄₉ is set to 85%.
As a material of the base material 49a and the filler 49b, an appropriate transparent resin can be adopted, but in the present embodiment, the same material as that of the base material 48a and the filler 48b is used.

The surface substrate 61 smoothes the fine irregularities formed by exposing the filler 49b to the surface on the observation side of the first diffusion layer 49, facilitates the formation of the surface coat layer 51, and the lenticular lens sheet 40. It is intended to suppress warping due to environmental changes such as temperature and humidity, and is composed of a light-transmitting substrate whose combination of linear expansion coefficient and moisture swelling coefficient, which are expansion characteristic values, and bending rigidity is the same as that of the lens substrate 42. . Here, the bending rigidity is a physical property value that almost controls warping deformation. The bending rigidity of a beam having a unit width in the vertical or horizontal cross section of the light transmitting portion, that is, the product of the longitudinal elastic modulus and the cube of the plate thickness. The amount is proportional to.
In the present embodiment, the same PET resin as the lens substrate 42 is used, and the thickness t _{2 is} 75 μm.

  The surface coat layer 51 is various coat layers that are provided as necessary to satisfactorily finish the surface properties of the transmission screen 20. For example, a hard coat (HC) layer for imparting scratch resistance to a surface with a pencil hardness of about 3H or more, an antiglare (AG) layer for preventing reflection, and an antistatic (AS) layer for preventing dust adhesion A coat layer having a function such as a single layer or a plurality of layers is formed.

In this way, the lenticular lens sheet 40 includes the three laminated substrates, ie, the lens substrate 42, the main substrate 60, and the surface substrate 61, which are bonded to each other via the bonding layer. A surface layer is formed on each outermost side.
Then, with respect to the symmetry axis S ₁ passing through the plate thickness center of the main board 60, the lens substrate 42 are arranged of the surface substrate 61 symmetrically. That is, as shown in FIG. 3, the lens substrate 42 from the axis of symmetry _{S 1,} when the distance to the inner surface of the surface substrate 61 and _T 1, _{T 2,} is _T 1 = T _2.
For this reason, the lens substrate 42 and the surface substrate 61 that form a symmetrical pair with respect to the symmetry axis S ₁ are made of the same material, and therefore have the same linear expansion coefficient, moisture swelling coefficient, and longitudinal elastic coefficient. Further, each of the plate thickness is _t 1 = _{t 2.} Therefore, the bending rigidity values of the lens substrate 42 and the surface substrate 61 are equal.
In contrast, the thickness of the center line, the main substrate 60 is a center substrate disposed on the symmetry axis S ₁ on the material, the lens substrate 42 is arranged at the outermost part with the plate thickness, and the surface substrate 61 different ing. In the present embodiment, the main rigidity of the lenticular lens sheet 40 is given by adopting PC resin for the main substrate 60 and setting the plate thickness to the maximum plate thickness.
The cylindrical lens 43, which is the surface layer, the surface coat layer 51, the adhesive layer 46, which is the bonding layer, the first diffusion layer 49, and the second diffusion layer 48, which is the coating layer, are all formed on each laminated substrate. Since it is made of a thin or low-rigidity material, the influence on warping deformation can be substantially ignored.

Next, the operation of the rear projection television 10 of the present embodiment will be described focusing on the operation of the transmissive screen 20.
First, the operation when the transmission screen 20 is placed in an environment where the temperature and humidity change will be described.
FIG. 4 is a schematic explanatory diagram for explaining an action of suppressing warpage deformation due to temperature / humidity changes of the transmission screen according to the first embodiment of the present invention.

When either temperature or humidity changes, as shown by arrows in FIG. 4, each laminated substrate expands and contracts in accordance with the respective linear expansion coefficient and moisture swelling coefficient, and expands and contracts in the direction along the plate surface. .
Then, stress is generated inside the lenticular lens sheet 40 due to the difference in expansion and contraction between the main substrate 60 and the lens substrate 42 and the front substrate 61. The internal stress to occur symmetrically in the thickness direction with respect to the symmetry axis S _1, are offset from one another, the plane of the lenticular lens sheet 40 is maintained. On the other hand, if such a symmetrical arrangement is not taken, the non-cancelling portion of the internal stress becomes an internal bending stress, causing a so-called bimetal effect, and the lenticular lens sheet 40 is warped.
For this reason, in this embodiment, even if any of temperature and humidity changes, the curvature of the lenticular lens sheet 40 is suppressed and a planar state can be maintained. On the other hand, since the Fresnel lens sheet 30 is warped to the lenticular lens sheet 40 side or a highly rigid substrate is employed, the lenticular lens sheet 40 arranged on the observation side is warped to the Fresnel lens sheet 30 side. Without the screen, the floating phenomenon of the screen can be prevented.
Therefore, manufacture and assembly of the lenticular lens sheet 40 are facilitated.

Next, the optical action of the transmission screen 20 will be described along the optical path.
As shown in FIG. 1, the projection light emitted from the projector 12 is deflected by the reflecting mirrors 13 and 14 and projected from the oblique lower side to the transmissive screen 20. Then, the light is incident on the third diffusion layer 33 of the Fresnel lens sheet 30, undergoes refraction and reflection, is diffused in the third diffusion layer 33 in which the filler 33 b is dispersed, and passes through the substrate portion 32.
The projection light transmitted through the substrate portion 32 is diffused according to the diffusion degree of the third diffusion layer 33, and enters the Fresnel lens portion 31 in a state where the diffusion has progressed by the thickness of the substrate portion 32. Then, the light is made substantially parallel light by being refracted by the Fresnel lens portion 31 and is emitted toward the lenticular lens sheet 40 in a direction substantially parallel to the optical axis P1.

The projection light incident on the lenticular lens sheet 40 is condensed in the left-right direction (horizontal direction) of the screen by the lens unit 44 and is formed into a stripe shape. Unnecessary non-condensing components are shielded by the BS layer 45, and the condensing components are transmitted through the light transmitting portion 47. The projected light is linearly imaged in the light transmitting portion 47 or in the vicinity of the boundary surface between the adhesive layer 46 and the light transmitting portion 47 according to the focal position of the cylindrical lens 43, and then the screen is moved in the horizontal direction of the screen. It becomes divergent light.
When the projection light is incident on the second diffusion layer 48, it is further diffused in the horizontal direction of the screen and also in the vertical direction (vertical direction), and the second diffusion is performed within the thickness t of the second diffusion layer 48. The diffusion gradually proceeds according to the diffusion degree of the layer 48, reaches the main substrate 60, propagates through the thickness t0, and then reaches the first diffusion layer 49.
When the diffused light reaches the first diffusion layer 49, it is diffused most intensely in accordance with the diffusion degree of the first diffusion layer 49, passes through the surface substrate 61 and the surface coat layer 51, and passes through the surface of the lenticular lens sheet 40. It is emitted to the outside.
Therefore, projection light that diffuses in a predetermined angle range in the vertical direction and the horizontal direction with respect to the normal direction of the screen is emitted from the transmissive screen 20 to the observation side. It is possible to appreciate the projection light within the range of the viewing angle.
In the present embodiment, the transmissive screen 20 does not warp or float even in an environment where temperature and humidity change, so that a stable image free from image distortion and image blur can be viewed.

In the present embodiment, since a plurality of diffusion layers are provided on the transmission screen 20 by a coating layer or a diffusion adhesive layer provided between laminated substrates, resolution, contrast, and brightness can be increased by distributing the diffusion degree to each. It is possible to reduce scintillation while maintaining good.
First, if the diffusion degree of the third diffusion layer 33 provided on the Fresnel lens sheet 30 side is too large, the image of the projected light is blurred and affects the resolution, and the non-shielded light is blocked by the BS layer 45 due to diffusion. Condensed components increase, light efficiency deteriorates, and contrast and brightness decrease.
Therefore, in order to prevent such a decrease in resolution, contrast, and brightness, the diffusion degree H ₃₃ of the third diffusion layer 33 is set smaller than H ₄₉ of the first diffusion layer 49. Since the lenticular lens sheet 40 also has the second diffusion layer 48, this can ensure that the degree of diffusion by the diffusion layer on the Fresnel lens sheet 30 side is smaller than the degree of diffusion by the diffusion layer on the lenticular lens sheet 40 side. It is set.

On the other hand, even with the same degree of diffusion, the amount diffused to the periphery of a certain diffusion angle range is smaller than the distribution evenly diffused to a certain diffusion angle range (hereinafter referred to as “uniform distribution type”). The distribution intensively diffused in the vicinity of the value (hereinafter referred to as “concentrated distribution type”) improves the light efficiency by reducing the light loss because the non-condensing component shielded by the BS layer 45 is reduced. can do.
In order to improve the light efficiency according to this principle, in this embodiment, H ₃₃ <H ₄₉ is set, and the difference in refractive index between the base material 33a and the filler 33b is set to be larger than the refractive index difference between the base material 49a and the filler 49b. It is said.
In general, the greater the difference in refractive index between the light diffusing material and the light diffusing substrate, the greater the refracting action or reflecting action at each interface and the wider the diffusion angle. Therefore, if the degree of diffusion is the same, the greater the difference in refractive index, the lower the dispersion concentration of the light diffusing material and the wider the space between the light diffusing materials.
In the present embodiment, in combination with H ₃₃ <H ₄₉ , the difference in spacing between the light diffusing materials due to the difference in refractive index appears more than in the case where the degree of diffusion is equivalent. Is a relatively sparse state in which the dispersion concentration of the filler 33b is low, and the first diffusion layer 49 is in a relative dense state in which the dispersion concentration of the filler 49b is high.
Therefore, the projection light transmitted through the third diffusion layer 33 receives a relatively concentrated distribution type diffusion, becomes a non-parallel component in the Fresnel lens portion 31, and has a large diffusion angle that is scattered by the BS layer 45. Is incident on the cylindrical lens 43 and the first diffusion layer 49 performs diffusion corresponding to the finally required viewing angle. Therefore, the light efficiency in diffusion is improved.

Next, the scintillation reducing action of such a configuration will be described.
Scintillation is a phenomenon in which high-intensity light in the form of minute spots that is not present in the original image is observed and the image flickers and feels glaring. The main cause is that there is a minute luminance unevenness formed by a light beam deviating from the normal optical path due to a manufacturing error or a minute defect of an optical element in the transmission screen being emitted in a specific direction within a viewing angle range. Conceivable.
In the present embodiment, as described above, as well as larger than the degree of diffusion of the most viewing side of the diffusion layer is a diffusion degree H ₄₉ the other diffusion layer of the first diffusion layer 49, a first diffusion layer 49 Filler 49b is a relatively dense state in which the dispersion concentration is high. Therefore, even if minute spot-like high-intensity light traveling in a specific direction is generated before reaching the first diffusion layer 49, strong diffusion of the uniform distribution type is performed in the first diffusion layer 49. High-intensity light is less likely to be emitted in a specific direction on the side, and combined with the fact that the projection light is diffused to some extent by the third diffusion layer 33, scintillation is reduced.

On the other hand, the first diffusion layer 49 must realize a desired viewing angle. That is, if the degree of diffusion is increased too much in order to eliminate scintillation, the viewing angle is expanded to an unnecessary range, and the light amount gain is reduced on the observation side, resulting in a dark image. In addition, the scintillation reduction effect is improved as the distance between the third diffusion layer 33 and the first diffusion layer 49 is increased. However, the first diffusion layer 49 is further away from the focal position of the cylindrical lens 43, and image blurring easily occurs. .
Therefore, in the present embodiment, in the lenticular lens sheet 40, the second diffusion layer 48 having a diffusion degree H ₄₈ of H ₄₈ <H ₃₃ is provided so that a part of the diffusion action of the first diffusion layer 49 can be shared. . Further, by providing the second diffusion layer 48 in the vicinity of the BS layer 45, the projection light near the focal position of the cylindrical lens 43 collected by the light transmitting portion 47 sandwiched between the BS layers 45 is second. The arrangement allows the diffusion layer 48 to diffuse on the incident surface.
Therefore, scintillation can be suppressed without unnecessarily widening the viewing angle due to the diffusion of the first diffusion layer 49, and the first diffusion layer is in a state where the divergence by the cylindrical lens 43 has progressed at a position away from the focal position. Compared with the case of diffusing only by 49, image blurring is reduced. Therefore, both suppression of scintillation and improvement of resolution can be achieved.
At this time, it is more preferable to make the incident surface of the second diffusion layer 48 coincide with the focal position of the cylindrical lens 43 because image blurring can be minimized.

[Second Embodiment]
Next, a transmissive screen and a projection display according to the second embodiment of the present invention will be described.
FIG. 5 is a partially enlarged view of a cross-sectional view in the same direction as FIG. 3 for describing a detailed configuration of a transmission screen according to a modification of the embodiment of the present invention.

  The transmission screen 200 of this embodiment includes a lenticular lens sheet 400 (light diffusion lens array sheet) instead of the lenticular lens sheet 40 of the transmission screen 20 of the first embodiment. Further, the rear projection television 100 of the present embodiment is obtained by replacing the transmission screen 20 of the first embodiment with a transmission screen 200 (see FIG. 1). Hereinafter, a description will be given centering on differences from the first embodiment.

  As shown in FIG. 5, the lenticular lens sheet 400 removes the second diffusion layer 48 and the main substrate 60 of the lenticular lens sheet 40 and replaces the lens substrate 42, the first diffusion layer 49, and the surface substrate 61 with a lens substrate. 62 (laminated substrate), a first diffusion layer 52, and a surface substrate 63 (laminated substrate).

Lens substrate 62, the surface substrate 63 is a flat plate member of light transmissive arranged symmetrically with respect to the symmetry axis S _2, each of the linear expansion coefficient, moisture swelling index, and a flexural rigidity equal Material . The material of the lens substrate 62 and the surface substrate 63 and the thicknesses t ₃ and t ₄ are appropriately set according to the size of the transmission screen 200 and the like so as to obtain necessary rigidity.
In this embodiment, all materials are made of PET resin, and the plate thicknesses t ₃ and t ₄ are set to be t ₃ = t ₄ = 0.075 mm, and are spaced apart by a distance T ₃ . The linear expansion coefficient is 1.5 × 10 ⁻⁵ (cm / cm / ° C.), and the moisture swelling coefficient is 1.2 × 10 ⁻⁵ (1 /% RH).

The first diffusion layer 52 is a diffusion layer composed of a base material 52a and a filler 52b having a refractive index difference similar to that of the base material 49a and the filler 49b, and is shared by the surface of the surface substrate 61 on the light source side. It is formed by laminating or coating by extrusion.
In FIG. 5, the thickness of the first diffusion layer 52 is depicted as the same thickness as the adhesive layer 46 including the BS layer 45, but the sum of the thickness of the adhesive layer 46 including the BS layer 45 is necessary. if a thickness T _3, the respective thicknesses may be different. The thickness T ₃ is set so that the viewing angle necessary to obtain in accordance with the magnitude of the degree of diffusion H _52.
Diffusion degree _{H 52} of the first diffusion layer 52 _is the same range as _{H 49.}

Thus, the transmissive screen 200, the laminated substrate is provided even number, their linear expansion coefficient, moisture swelling coefficient, flexural rigidity, and the arrangement positions are disposed symmetrically with respect to the symmetry axis S _2, each of the laminated substrate The outermost layer is provided with a surface layer, and a bonding layer is provided between the respective laminated substrates.

Next, the operation of the rear projection television 100 will be described. The description will focus on the differences from the first embodiment.
FIG. 6 is a schematic explanatory diagram for explaining an action of suppressing warpage deformation due to temperature / humidity changes of the transmission screen according to the second embodiment of the present invention.

When either temperature or humidity changes, each laminated substrate expands and contracts according to the linear expansion coefficient and the moisture swelling coefficient, which are expansion characteristic values, as indicated by arrows in FIG.
In this case, since the expansion characteristic values causing the lens substrate 62 and the surface substrate 63 to expand and contract are equal, the expansion and contraction amounts are the same. Therefore, the flatness of the lenticular lens sheet 400 is maintained.
For this reason, in the present embodiment, even if the temperature and humidity change, the warp of the lenticular lens sheet 400 is suppressed, so that a so-called floating phenomenon does not occur, and the transmission screen 200 is deteriorated in image quality due to resolution degradation or the like. Can be prevented.

  In the present embodiment, the number of laminated substrates is reduced by one from the first embodiment, so that the configuration is simpler. In addition, since the diffusion layer is also reduced, they combine to form an efficient transmission screen with little light loss.

Next, the evaluation results of Examples and Comparative Examples of the transmission screens 20 and 200 according to the first and second embodiments of the present invention will be described.
The schematic configurations of the cross sections of the lenticular sheets of Examples 1 to 3 and the comparative example are as described in the following description and Table 1. However, due to the space in the table, (cm / cm) is omitted from the unit notation of the linear expansion coefficient.
Example 1 has a configuration corresponding to FIG. 3 of the first embodiment, in which the lens substrate in Table 1 is the lens substrate 42, the central substrate is the main substrate 60, and the surface substrate is the surface substrate 61, and the axis of symmetry. They are arranged symmetrically with respect to S _1.
In the second embodiment, a base material having the same material and thickness as in the first embodiment is used, the adhesive layer 46 and the second diffusing layer 48 are made the same, and a light diffusing material is dispersed and mixed in the adhesive layer 46. This is a diffusion layer.
Example 3 has a configuration corresponding to FIG. 5 of the second embodiment, the lens substrate is the lens substrate 62 in Table 1, the surface substrate has a surface substrate 63 are arranged symmetrically with respect to the symmetry axis S ₂ ing.
In the comparative example, a diffusion plate in which a light diffusing material is dispersed is provided in place of the central substrate and the surface substrate, and a two-lens structure is formed with a lens substrate on which a cylindrical lens is formed. As can be seen from Table 1, the diffuser plate and the lens substrate in this case are different in material and thickness, and have a configuration with no symmetry in the arrangement of the linear expansion coefficient, the moisture swelling coefficient, and the bending rigidity.
In addition, since this evaluation evaluates the curvature of a lenticular sheet etc., the Fresnel lens sheet is common in all the examples, and the Fresnel lens sheet 30 of the said embodiment is used.

The evaluation results are shown in Table 2 below. Evaluation items are resolution, scintillation, flatness of the lenticular sheet, and floating of the screen at high temperature and high humidity.
The resolution and scintillation were evaluated by visual evaluation of the images projected on each transmission screen, and evaluated in four levels: very good, good, slightly bad, and bad, and indicated by ◎, ○, △, and ×, respectively. Yes.
The flatness of the lenticular sheet is an evaluation of the amount of warp deformation.
Screen floating is visually judged on the degree of screen floating in a high-temperature and high-humidity environment with a temperature of 40 ° C. and a humidity of 95%, and is evaluated in four stages: almost inconspicuous, slightly inconspicuous, very conspicuous, They are indicated by ◎, ○, Δ, and ×, respectively.

As shown in said table, Examples 1-3 were the result of (circle) or (double-circle) in each evaluation item. Example 1 showed the best results.
On the other hand, in the comparative example, although the resolution and scintillation were good, the flatness of the lenticular sheet and the floating of the screen were somewhat conspicuous, resulting in inferior results to Examples 1-3.

In the above description, a plurality of laminated substrates have been described as an example in which the linear expansion coefficient, moisture swelling coefficient, bending rigidity, and arrangement position are arranged so as to have symmetry in the thickness direction. However, as long as the amount of contribution to the internal stress that induces the warp of the light diffusing lens array sheet is small, it is not necessary to have perfect symmetry, and it is only necessary to be substantially symmetrical.
For example, in the example shown in the first embodiment, the central substrate has a relatively large rigidity. Therefore, when there is a large difference in rigidity between the pair of other laminated substrates that should have symmetry and the relatively low rigidity of the central substrate, the linear expansion coefficient and moisture swelling coefficient of the pair that should have symmetry It suffices if the thickness is approximately symmetrical with respect to the value of the central substrate.

  In the above description, the case where the number of laminated substrates is an odd number and an even number has been described in the case of three and two respectively, but the linear expansion coefficient, moisture swelling coefficient, bending rigidity, and arrangement position are As long as it has substantially symmetry in the thickness direction, it may be composed of a larger number of laminated substrates.

  In the description of the first embodiment, the example in which the bending rigidity of the central substrate is maximized has been described. However, if the bending rigidity arrangement is substantially symmetric, the bending rigidity of the laminated substrates other than the central substrate is You may make it the maximum.

  Further, in the above description, the same material and the same thickness are used in order to make the bending rigidity of the substantially symmetrical pair of laminated substrates substantially symmetrical, but different if the linear expansion coefficient and moisture swelling coefficient are substantially the same. The material may have a different thickness, and the bending rigidity may be substantially symmetric. In this case, the symmetry of the arrangement position makes the position of the neutral plane of the laminated substrate symmetrical.

In the above description, in order to improve optical characteristics such as scintillation, for example, a plurality of diffusion layers are provided between laminated substrates, or provided as a bonding layer. It is not limited to.
For example, the laminated substrate may be constituted by a light diffusing plate in which a light diffusing material is dispersed in a light-transmitting base material, or a surface provided on the outermost laminated substrate surface among a plurality of laminated substrates. A light diffusing material may be dispersed in the layer to form a diffusion layer.

  Further, in the above description, as an example of the expansion characteristic value, the linear expansion coefficient and the moisture swelling coefficient have been described as being symmetrically arranged. However, in the pair that should have symmetry, the linear expansion coefficient and the moisture swelling coefficient are In the case where the difference between and is sufficiently large and the characteristic that contributes to the warping is substantially only one, the expansion coefficient with little contribution may not be symmetric.

It is a schematic explanatory drawing in the cross section containing the optical axis of the projection optical system for demonstrating the projection type display which concerns on the 1st Embodiment of this invention. FIG. 2 is an explanatory cross-sectional view along the direction perpendicular to the paper surface in FIG. 1 for explaining the schematic configuration of the transmission screen according to the first embodiment of the present invention. It is the elements on larger scale of FIG. 2 typically expressed in order to demonstrate the detailed structure of the transmission type screen which concerns on the 1st Embodiment of this invention. FIG. 5 is a schematic explanatory diagram for explaining an action of suppressing warpage deformation due to temperature / humidity changes of the transmission screen according to the first embodiment of the present invention. It is the elements on larger scale of the same direction sectional view as Drawing 3 for explaining the detailed composition of the transmission type screen concerning the modification of the embodiment of the present invention. It is a schematic explanatory drawing for demonstrating the suppression effect of the curvature deformation by the temperature and humidity change of the transmission type screen which concerns on the 2nd Embodiment of this invention. It is a schematic explanatory drawing explaining the principle of generation | occurrence | production and suppression of the floating phenomenon of the transmission type screen in a prior art.

Explanation of symbols

10, 100 Rear projection television (projection display)
20, 200 Transmission type screen 30 Fresnel lens sheet 31 Fresnel lens part 33 Third diffusion layers 33a, 48a, 49a, 52a Base material (light transmission base material)
33b, 48b, 49b, 52b Filler (light diffusing material)
40, 400 Lenticular lens sheet (light diffusion lens array sheet)
42, 62 Lens substrate 43 Cylindrical lens 44 Lens part (surface layer)
45 BS layer 46 Adhesive layer (bonding layer)
47 Light transmission portion 48 Second diffusion layer 49, 52 First diffusion layer 51 Surface coat layer (surface layer)
53, 63 Surface substrate 60 Central substrate P1 Optical axis

Claims (5)

A transmissive screen having a Fresnel lens sheet that makes projection light projected from a light source substantially parallel light, and a light diffusion lens array sheet that diverges projection light made substantially parallel light by the Fresnel lens sheet,
The light diffusing lens array sheet has a plurality of light-transmitting laminated substrates arranged in the thickness direction, a bonding layer for bonding adjacent ones of the plurality of laminated substrates, and the thickness direction A surface layer formed on the outermost surface of the laminated substrate,
The transmissive screen, wherein the plurality of laminated substrates are arranged so as to be substantially symmetrical in the thickness direction in terms of expansion characteristic value, bending rigidity, and arrangement position.   2. The transmission type screen according to claim 1, wherein each pair of laminated substrates having substantially symmetry among the plurality of laminated substrates is made of substrates of the same material and the same thickness. The plurality of laminated substrates have an odd number of configurations;
Among the plurality of laminated substrates, a central substrate arranged at the center in the thickness direction and a pair of peripheral substrates arranged on the peripheral side in the thickness direction are made of different materials. The transmission screen according to claim 1 or 2.   The transmissive screen according to claim 1, wherein the bonding layer is a diffusion adhesive layer having light diffusibility by dispersing a light diffusing material in a light transmissive adhesive.   A projection display comprising the transmissive screen according to claim 1.

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