JP5230100B2 - Reflective screen - Google Patents

Description

  The present invention relates to a reflective screen for a projector that reflects and projects an image projected from a projector, and more particularly to a reflective screen that can project an image with almost no color change even when viewed from an oblique position. .

  In order to reflect the image projected by the projector and display it on the screen, a two-layer reflective screen is known that includes a reflective layer that reflects the light from the projector and a light diffusion layer that diffuses the reflected light. ing. In such a two-layer reflective screen, a reflective layer having a substantially constant reflectivity regardless of the wavelength with respect to visible light, such as an aluminum vapor deposition layer or an aluminum paste coating layer, is used as the reflective layer. By further diffusing the reflected light with the light diffusion layer, it is possible to view an image without glare with a relatively wide viewing angle.

  However, such a reflective screen reflects and diffuses even when ambient light (environment light) other than image light enters the screen. Therefore, when projection is performed in a bright environment, reflected diffused light due to ambient light or the like is generated in a dark display portion of an image. As a result, the brightness of the dark display portion increases, leading to a decrease in the contrast of the image, resulting in an image that is difficult to see. Conventionally, the only way to prevent this has been to darken the room, but as projectors become more widespread, there is an increasing demand for reflective screens that can display high-contrast images even in bright environments.

  Therefore, as a reflection type screen capable of projecting a high-contrast image even in a bright environment, as shown in FIG. 7, light of a specific wavelength is selectively reflected on a substrate 1 having a light absorption property. Has been proposed in which a reflective layer 2 and a light diffusion layer 3 for diffusing reflected light are sequentially formed (Patent Document 1). Such a reflective screen 6 has three primary colors of light constituting a projector image, that is, blue (B) by the reflective layer 2 using an optical multilayer film that selectively reflects light of a specific wavelength by light interference. ), Green (G), and red (R) only the primary color wavelength region light is selectively reflected, and the light of other wavelengths is transmitted and absorbed by the base material 1 so that it can be projected even in a bright environment. It is possible to display an image with high contrast while suppressing an increase in the brightness of the dark display portion.

  However, Patent Document 1 mentions only the diffusibility of reflected light, but it is not a light diffusing layer in consideration of the emission of backward diffused light with respect to incident light, and high contrast in a bright environment is not sufficient. There wasn't.

  Therefore, the same applicant as the applicant of the present invention uses a light diffusion layer that hardly generates back diffused light so that high contrast in a bright environment can be realized. A type screen (Japanese Patent Application No. 2004-269691) was proposed.

  However, the light diffusing layer comprising the transparent spherical fine particles shown here and a transparent binder having a different refractive index is different in light diffusibility depending on the wavelength of incident light. Because the light diffusibility differs for each of the three primary colors of green and red, there is a problem that the image color changes when viewed from an image projected from an observer at an oblique position with respect to the screen. It was.

Japanese Patent Laying-Open No. 2003-333781 (Claim 1)

  Therefore, the present invention is a reflective screen capable of projecting a high-contrast video and a video having high video color reproducibility, particularly a video having almost no color change when the screen is viewed from an oblique position. The purpose is to provide.

  The reflective screen of the present invention has light reflectivity with respect to light in the blue, green, and red wavelength regions, and each average reflectance of the light in the wavelength regions is other than the wavelength region in the visible wavelength region. The reflective screen has a reflection layer higher than the average reflectance of light, and the reflection type screen is a light diffusion layer composed of fine particles and a transparent binder on the incident surface side of the reflection layer that reflects the light in each wavelength region. Each of the wavelength regions of fine particles contained per unit area of the light diffusion layer located on the incident surface side with respect to each reflection layer that has at least one layer and reflects the light of each wavelength region The total scattering cross-sections at the central wavelengths are substantially the same.

  The reflective screen of the present invention has light reflectivity for light in the blue, green, and red wavelength regions, and the average reflectance of the light in the wavelength regions is the wavelength region in the visible wavelength region. A reflective screen having a reflective layer higher than the average reflectance of light other than the above, wherein the reflective screen is formed of fine particles and a transparent binder on the incident surface side with respect to the reflective layer that reflects the light in each wavelength region. At least one light diffusing layer, and the fine particles contained per unit area of the light diffusing layer located on the incident surface side of the reflecting layer that reflects light in the blue wavelength region, The total scattering cross section at the center wavelength and the fine particles contained per unit area of the light diffusion layer located on the incident surface side of the reflection layer reflecting the light in the green wavelength region at the center wavelength in the green wavelength region Total scattering And the total scattering cross section at the central wavelength of the red wavelength region of the fine particles contained per unit area of the light diffusion layer located on the incident surface side of the reflection layer that reflects light in the red wavelength region. , Which are substantially the same.

  In the reflective screen of the present invention, preferably, the reflective layer having light reflectivity with respect to light in the blue, green, and red wavelength regions reflects light in each of the blue, green, and red wavelength regions. It consists of two reflective layers.

  Preferably, the reflection layer includes three reflection layers that reflect light in each of the wavelength regions of blue, green, and red, and the fine particles 1 in the light diffusion layer at the center wavelengths of the wavelength regions. A reflection layer in a wavelength region having a large scattering cross section is provided on the incident surface side.

  More preferably, the light diffusing layer is located further on the incident surface side of the reflective layer located closest to the incident surface side, and the reflective layer located closest to the incident surface side and the reflective layer located second from the incident surface side And / or between the second reflective layer and the third reflective layer from the incident surface side.

The reflective screen of the present invention preferably has a plurality of light diffusion layers, and each light diffusion layer is composed of the same fine particles and the same transparent binder.
More preferably, in the plurality of light diffusion layers, the thickness of the layer or the content of the fine particles is adjusted according to the size of the scattering cross section of each fine particle at the center wavelength of each wavelength region. Features.

  Preferably, the reflective layer is made of a transparent polymer resin.

  More preferably, the reflective layer is formed by a multilayer extrusion method.

  Preferably, a light absorption layer that absorbs light transmitted through the reflection layer is provided on a surface different from the incident surface side of the reflection layer.

  Preferably, all of the light diffusion layers are laminated so that the haze in JIS K7105: 1981 is 60% or more, the total light transmittance in JIS K7361-1: 1997 is 70% or more, and the reflection in JIS Z8722: 2000. The tristimulus value Y in the method is 10 or less.

  More preferably, the light diffusion layer is composed of transparent spherical fine particles and a transparent binder having a refractive index different from that of the spherical fine particles, and the spherical fine particles have an average particle diameter of 1 μm to 10 μm. The value obtained by dividing the ratio by the refractive index of the transparent binder is 0.91 or more and 1.09 or less (excluding 1.00).

  According to the present invention, a reflective screen capable of projecting a high-contrast video and a video having high video color reproducibility, particularly a video with little color change when viewed from an oblique position. Can be obtained.

Hereinafter, embodiments of the reflective screen of the present invention will be described.
The reflective screen of the present invention includes a light-absorbing base material, a reflective layer, and a light diffusion layer. The reflective layer has light reflectivity with respect to light in the blue, green, and red wavelength regions, and each average reflectance of the light in the wavelength region is an average of light in the visible wavelength region other than the wavelength region. It consists of a reflective layer having a higher reflectance. The light diffusing layer is composed of a light diffusing layer made of at least one transparent binder and fine particles disposed on the incident surface side with respect to the reflecting layer that reflects light in each wavelength region. Further, the light diffusion layer is a center wavelength of each of the wavelength regions of the fine particles included per unit area of the light diffusion layer located on the incident surface side of each reflection layer that reflects the light of each wavelength region. The total scattering cross sections at are substantially the same.

  Here, blue (B), green (G), and red (R) are the three primary colors of light constituting the projector image, and are approximately blue (B: 420 nm to 480 nm, center wavelength 450 nm), green (G: 520 nm to 580 nm, central wavelength 550 nm), and red (R: 590 nm to 650 nm, central wavelength 620 nm). In the present invention, the visible wavelength region refers to light in the wavelength region of about 380 nm to 670 nm. In the present invention, the reason why the visible wavelength region is set to such a range is that the light sensitivity in the region exceeding 670 nm is perceived by the observer even if the light sensitivity is very low and the light in this region is reflected. This is because there is almost no effect on the color or contrast of the observed image light. Hereinafter, embodiments of each component will be described.

  First, the reflective layer will be described. The reflection layer has light reflectivity with respect to light of three primary colors constituting the image projected from the projector, that is, light of the three primary color wavelength regions of B, G, and R, and light in the wavelength region of B, G, and R The average reflectance of each of the above is higher than the average reflectance of light outside the wavelength region in the visible wavelength region.

  Due to the action of the reflective layer, in the reflective screen according to the present invention, most of the primary color wavelength region light constituting the projector image is reflected, whereas in the case of ambient light, the light is spread over a wide wavelength region. Therefore, there are more components that pass through the reflective layer and are not reflected compared to the projector light. Therefore, in the present invention, it is possible to relatively reduce the reflection of ambient light without reducing the image light from the projector. As a result, it is possible to obtain a clear image with high contrast even when the contrast projected on the reflective screen is suppressed and the projection environment is bright.

  Here, the average reflectance means the average of the reflectance for each wavelength in a specific wavelength range, but in the present invention, the visible wavelength region (wavelengths from 380 nm to 670 nm) is an equally spaced wavelength of 10 nm or less. What was calculated | required using the reflectance measured for every is made into an average reflectance. The average reflectance of light in the B, G, and R wavelength regions can be obtained by averaging the reflectance of light within the wavelength range for each range. The average reflectance of light outside the B, G, and R wavelength regions within the visible wavelength region can be obtained by averaging the reflectance of light in all regions other than the B, G, and R wavelength regions.

  Such a reflective layer is a band-pass filter that reflects light in the B, G, and R wavelength regions and transmits light in other wavelength regions, and alternately includes at least two types of transparent dielectrics having different refractive indexes. It is an optical multilayer film obtained by a general method of laminating a large number of layers.

The reflective layer can also be produced by alternately laminating inorganic thin films such as titanium oxide (TiO ₂ ) and magnesium fluoride (MgF ₂ ). However, the transparent polymer resin and transparent having a different refractive index are used. From the viewpoint of productivity, an optical multilayer film in which various polymer resins are alternately laminated may be used. Examples of the transparent polymer material include polycarbonate (PC), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). Moreover, the combination from which these refractive indexes differ may select the combination from which these refractive indexes differ, and what changed the degree of extending | stretching and changed the refractive index with the same material may be sufficient. Furthermore, the reflective layer is preferably formed by a multilayer extrusion method of polymer resin.

  Here, the film thickness of the dielectric to be laminated needs to be 1/4, 5/4, 9/4,... Of the wavelength reflected by the optical film thickness (= refractive index × film thickness). is there. Also, the greater the difference in refractive index between the two types of dielectrics to be stacked, the higher the reflectance at the same number of layers. However, even when this difference is small, it is possible to achieve the same reflectivity by increasing the number of stacked layers.

  The wavelength band becomes wider as the difference in refractive index between the two types of dielectrics to be laminated increases. However, even for a combination of materials with a small difference in refractive index and a narrow wavelength band, the thickness of the dielectric layer to be laminated is slightly smaller than the center value (the optical thickness satisfying a predetermined relationship with the wavelength of light in the wavelength region). The band can be widened by stacking a large number of fluctuated ones. Therefore, such a method is effective for widening the band when using a combination of dielectrics having a small difference in refractive index, such as a combination of polymer resins. By widening the band of the B, G, and R wavelength regions, a reflective screen having good selective reflectivity can be obtained regardless of the projector model.

  The average reflectance of light in the B, G, and R wavelength regions when a reflective screen is used is not particularly limited, but is preferably 25% or more, and more preferably 30% or more. Further, the reflective layer has a difference of 10% or more between the average reflectance of light in the B, G, and R wavelength regions and the average reflectance of light in the visible wavelength region other than the wavelength region, Is preferably 15% or more, more preferably 20% or more.

  Further, the maximum reflectance of light in the B, G, and R wavelength regions when a reflective screen is used is not particularly limited, but is preferably 40% or more, and more preferably 50% or more. Further, the reflection layer has a difference between the maximum reflectance of light in the B, G, and R wavelength regions and the average reflectance of light in the visible wavelength region other than the wavelength region is 25% or more, Further, it is preferably 30% or more. As described above, the difference between the average reflectance and the maximum reflectance of the light in the B, G, and R wavelength regions and the average reflectance of the light in the visible wavelength region other than the wavelength region is as described above. By setting the range, it is possible to relatively reduce the reflection of the ambient light without reducing the image light from the projector, so that the reduction of the contrast of the image projected on the reflective screen is suppressed and the projection environment is bright. Even in this case, a clear image with high contrast can be obtained.

  The reflective layer used in the present invention has a highly light-reflective region with respect to one of the three wavelength regions of B, G, and R, and has a high light transmittance for at least the visible wavelength region other than the wavelength region. All the three primary color wavelength regions of B, G, and R are reflected by optically adhering three types of materials having a property. Further, one reflective layer may be a reflective layer having a high reflectance region in the wavelength region of 2 or 3. When the reflective layer is composed of two or more layers, the stacking order needs to be varied depending on the scattering cross section for each wavelength region of the fine particles constituting the light diffusion layer described later.

  Such a reflective layer is usually provided on a substrate. Such a substrate serves as a support for the reflective screen of the present invention, and a plate or a sheet can be selected depending on the application. As such a substrate, transparent or opaque materials such as glass, metal, and polymer resin can be used. Examples of the resin include polycarbonate (PC), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). ), Polyethersulfone (PES), polyolefin (PO) and the like.

  Moreover, it is preferable that the reflection type screen of this invention has the light absorption layer which absorbs the light which permeate | transmitted the reflection layer in the surface different from the entrance plane side of the said reflection layer mentioned above. By having the light absorption layer in this way, the light absorption layer absorbs the light transmitted through the reflection layer, so that reflection of the light transmitted through the reflection layer can be prevented. As a result, it becomes possible to obtain only the light in the B, G, and R wavelength region as reflected light as described above, preventing the dark display portion of the projector image from becoming bright due to the reflection of the ambient light, and reducing the contrast. Can be prevented.

  Such a light absorption layer can be formed by coating a black paint or the like on one surface or both surfaces of the substrate. When the light absorption layer is provided on one surface of the base material, the reflection layer may be provided on the light absorption layer. When the base material is transparent, it has the light absorption layer of the base material. You may provide in the surface opposite to a surface. Moreover, you may use what made the base material itself black by kneading light absorbers, such as a black pigment, in the said base material. Thus, the light absorbing layer is preferably a black film in which a black paint or the like is coated on the base material or the base material itself is black.

Next, the light diffusion layer will be described.
In the reflection type screen of the present invention, at least one light diffusion layer is provided on the incident surface side of the reflection layer described above. The light diffusion layer is composed of fine particles and a transparent binder, and preferably, the transparent spherical fine particles and the spherical fine particles are composed of transparent binders having different refractive indexes. Such a light diffusing layer is provided in order to diffuse the light reflected by the above-described reflecting layer to eliminate glare in the image and allow the image to be viewed with a wide viewing angle.

  Furthermore, the light diffusion layer of the present invention improves the wavelength dependence of light diffusion, and for each wavelength region reflected by the reflection layer, a light diffusion layer located on the incident side of the reflection layer (in the case of multiple light diffusion layers, The total scattering cross-sectional area of the fine particles contained per unit area of the total) is substantially the same.

That is, for example, the total scattering cross section at the center wavelength of the blue wavelength region of the fine particles contained per unit area of the light diffusion layer located on the incident surface side of the reflection layer that reflects light in the blue wavelength region , The total scattering cross section at the center wavelength of the green wavelength region of the fine particles contained per unit area of the light diffusion layer located on the incident surface side of the reflection layer that reflects the light in the green wavelength region, and the red The total scattering cross section at the central wavelength of the red wavelength region of the fine particles contained per unit area of the light diffusion layer located on the incident surface side of the reflection layer that reflects light in the wavelength region is substantially the same. It is.
Here, “substantially the same” means that the smallest one of the total scattering cross-sections at the respective central wavelengths in each wavelength region is based on the smallest one within 120%, preferably within 110%. More preferably, it is within 105%.

Here, the total scattering cross section per unit area is obtained by multiplying the scattering cross section of one fine particle by the number of particles per unit area. The scattering cross section Q of one of the fine particles, for fine spherical particles, the refractive index of the fine particles n _s, a diameter D, and the refractive index n _m of the transparent binder, and the wavelength of the incident light to λ below It can be obtained by equation (1).

It is. In addition, ψ _j ′ (z) and ζ _j ′ (z) in Equation (2) and Equation (3) represent the differentiation of ψ _j (z) and ζ _j (z) with respect to z, respectively, J _{j + 1/2} (z) and Y _{j + 1/2} (z) in equation (7) are the first type and second type Bessel functions, respectively.

  As is clear from the above formula, the scattering cross section of one fine particle is determined by the wavelength of the incident light, the particle size and refractive index of the spherical fine particles used for the light diffusion layer, and the refractive index of the transparent binder. Can be calculated. If there is a distribution in the particle diameter, the scattering cross section Q of one fine particle can be obtained by using the average particle diameter. The number of particles per unit area can be obtained by actual measurement, but can also be obtained by calculation from the density (true specific gravity) and average particle diameter of the fine particles and the transparent binder.

Further, as apparent from the above formula, the scattering cross section varies depending on the wavelength of incident light even if the same spherical fine particles and a transparent binder are combined. Scattering cross section in the way of _{example, n s = 1.50, n m} = B for 1.60 geometric cross-sectional area S of the spherical particles in the case of ^{(= πD 2/4),} G, R center wavelength of each wavelength region The change of the ratio of Q (= Q / S) with respect to the particle diameter D is illustrated (FIG. 2).

  Since the magnitude of the total scattering cross section per unit area (hereinafter simply referred to as the total scattering cross section) is directly related to the size of the light diffusivity, the total scattering cross sections at the central wavelengths in the B, G, and R wavelength regions are different. This means that the light diffusivity differs for each of the B, G, and R wavelength region lights. In other words, when there is one light diffusion layer on the incident surface side of the reflection layer of B, G, R, the spread of the angle for each wavelength region light of B, G, R will be different, with respect to the screen The video color changes depending on the viewing position (angle). In particular, this phenomenon becomes remarkable in a screen having a large diffusibility so that an image can be viewed with a wide viewing angle.

  However, in the present invention, it is possible to avoid such a phenomenon by making the total scattering cross sections substantially the same for each of the B, G, and R wavelength region lights.

  A specific method for making the total scattering cross sections substantially the same for each of the B, G, and R wavelength region light in the light diffusion layer of the reflective screen of the present invention will be described with reference to FIG. FIG. 1 illustrates the case where the reflective layer is formed by laminating three types of reflective layers having reflectivity in any one of the B, G, and R wavelength regions. The reflective layers Ra, Rb, and Rc are each a reflective layer having reflectivity in any one of the B, G, and R wavelength regions, and the reflective layer Ra receives the light (a) in the a wavelength region. Rb reflects light (b) in the wavelength region b, and the reflective layer Rc reflects light (c) in the wavelength region c.

Here, the light diffusion layer S1 on the reflection layer Ra closest to the light incident side, the light diffusion layer S2 between the reflection layer Ra and the reflection layer Rb, and the light diffusion layer between the reflection layer Rb and the reflection layer Rc Assuming S3, for these light diffusion layers S1, S2, and S3, the total scattering cross-sections of the fine particles contained therein are ΣQa ₁ and ΣQb _{1 in the} light diffusion layer S1 for light in the wavelength regions a, b, and c, respectively. , ΣQc ₁ , ΣQa ₂ , ΣQb ₂ , ΣQc _{2 for} the light diffusion layer S ₂ , and ΣQa ₃ , ΣQb ₃ , ΣQc ₃ for the light diffusion layer S ₃ . Making the total scattering cross section substantially the same for each of the B, G, and R wavelength region lights means that the light (a) in the wavelength region a has the diffusibility of the light diffusion layer S1 and the light in the wavelength region b For (b), the diffusivity of the light diffusion layers S1 and S2, and for the light (c) in the wavelength region of c, the diffusivities of the light diffusion layers S1, S2 and S3 are made equal, and ΣQa ₁ ≈ ( (ΣQb ₁ + ΣQb ₂ ) ≈ (ΣQc ₁ + ΣQc ₂ + ΣQc ₃ ) In order to satisfy this condition, if the total scattering cross sections ΣQa ₁ , ΣQb ₁ , ΣQc _{1 for} each wavelength region in the light diffusion layer S 1 closest to the light incident side are ΣQa ₁ > ΣQb ₁ > ΣQc ₁ , The reflective layer Ra, the reflective layer Rb, and the reflective layer Rc are arranged in order from the incident side, and the value of ΣQb ₂ is the difference between ΣQa ₁ and ΣQb ₁ (ΣQa ₁ −ΣQb) between the reflective layer Ra and the reflective layer Rb. ₁ ) is disposed, and a light diffusing layer S3 having a value of ΣQc ₃ of {ΣQa ₁ − (ΣQc ₁ + ΣQc ₂ )} is disposed between the reflective layer Rb and the reflective layer Rc.

  That is, when the reflective layers in the wavelength regions of B, G, and R are laminated, the reflective layer in the wavelength region that constitutes the light diffusion layer and in which the scattering cross-sectional area of one fine particle becomes large becomes closer to the incident surface side. The layer structure is as follows. In addition, the difference between the total scattering cross section at the center wavelength of the reflection wavelength region of the reflection layer on the most incident surface side and the total scattering cross section at the center wavelength of the reflection wavelength region of the second reflection layer from the incident surface side. Is formed between these two reflective layers with a total scattering cross section. Similarly, a light diffusion layer having a total scattering cross section as a difference between the total scattering cross sections of the second and third reflection layers from the incident surface side is formed between these reflection layers. In the present invention, each of the B, G, and R wavelength region reflecting layers reflects only B, G, or R, and exhibits high transmittance in other visible wavelength regions, so that the above-described configuration is possible. It becomes.

In this case, since the total scattering cross section is proportional to the number of fine particles per unit area, the total scattering cross sections ΣQa ₁ , ΣQb ₁ , and ΣQc ₁ for each wavelength region of the light diffusion layer S 1 closest to the light incident side are determined. For the light diffusing layer S2 and the light diffusing layer S3, the combination of the constituent fine particles and the binder material is the same as that of the light diffusing layer S1, and the above conditions can be easily obtained by adjusting the thickness of the layer or the content of the fine particles. Can be met. Although it is possible to satisfy the above conditions by changing the combination of the fine particles and the binder material constituting the light diffusion layer, according to the above method, the light diffusion layer (most light incident side) selected arbitrarily B) by determining the stacking order of the reflective layers based on the total scattering cross-sectional area of the layer) and adjusting the thickness and / or the content of fine particles of the light diffusion layer disposed between the reflective layers. , G, and R can be made substantially the same in total scattering cross section for each wavelength region light.

FIG. 1 illustrates the case where three types of reflective layers are laminated. For example, when one reflective layer reflects light in two to three wavelength regions of B, G, and R, On such a reflective layer, a light diffusing layer having the same total scattering cross section in the wavelength range of 2 to 3 may be disposed on the light incident side of the reflective layer. In other words, when the total scattering cross-sections in the two to three wavelength regions of the arbitrarily selected light diffusion layer are equal, a reflective layer that reflects light in those wavelength regions (one or more layers may be laminated). ) May be used. In the example of FIG. 1, for example, if the total scattering cross sections ΣQa ₁ , ΣQb ₁ , and ΣQc _{1 of} the fine particles constituting the light diffusion layer S ₁ are ΣQa ₁ ≈ΣQb ₁ ≈ΣQc ₁ (≈ means substantially the same). A light reflecting layer is not required between the reflecting layer Ra and the reflecting layer Rb and between the reflecting layer Rb and the reflecting layer Rc.

  Specific examples of the structure of the reflection type screen 6 of the present invention are shown in FIGS. For example, when the scattering cross-sections of one fine particle at the center wavelength of each wavelength region of B, G, and R are all different (for example, when B> G> R) for an arbitrarily selected light diffusion layer The light diffusion layer 31, the B reflection layer 21, the light diffusion layer 32, the G reflection layer 22, the light diffusion layer 33, and the R reflection layer 23 are stacked in this order from the incident surface side (FIG. 3). Further, when two of the scattering cross sections of one fine particle at the center wavelength in each wavelength region of B, G, and R are the same, for example, when B> G = R, the light diffusion layer from the incident surface side 31, B reflection layer 21, light diffusion layer 32, G reflection layer 22, adhesive layer 5, and R reflection layer 23 are laminated in this order (FIG. 4). In this case, either the G reflection layer 22 or the R reflection layer 23 may be on the incident surface side. For example, in the case of B = G> R, the light diffusion layer 31, the B reflection layer 21, the adhesive layer 5, the G reflection layer 22, the light diffusion layer 32, and the R reflection layer 23 from the incident surface side. They are laminated in order (FIG. 5). In this case, either the B reflection layer 21 or the G reflection layer 22 may be on the incident surface side. Further, when the scattering cross-sections of one fine particle at the center wavelength in each of the wavelength regions of B, G, and R are all the same (B = G = R), all of the light diffusion layers 31 (3) from the incident surface side These reflective layers are laminated by bonding with the adhesive layer 5. In this case, the order of the B reflection layer 21, the G reflection layer 22, and the R reflection layer 23 is not limited (FIG. 6).

  Regarding the optical characteristics of the light diffusion layer, when only all the light diffusion layers are laminated, the haze in JIS K7105: 1981 is 60% or more, preferably 70% or more, and the total light transmittance in JIS K7361-1: 1997 is 70% or more, preferably 80% or more, and Y of the tristimulus value in the reflection method of JIS Z8722: 2000 is 10 or less, preferably 8 or less.

  By using light diffusing layers having such optical characteristics, back diffused light generated when ambient light other than image light from the projector enters each light diffusing layer (opposite to the traveling direction of the incident light). (Light diffused in the direction) can be reduced, so that the dark display portion of the projector image can be prevented from becoming bright even when projected in a bright environment, and an image with higher contrast can be displayed. .

  The transparent binder constituting such a light diffusing layer is not particularly limited as long as it is transparent and can uniformly hold spherical fine particles. Examples thereof include fluids such as liquids and liquid crystals, and solids such as glass and polymer resins. However, a polymer resin is preferable from the viewpoints of handleability and dispersion stability.

  The glass used as the transparent binder is not particularly limited as long as the light transmittance of the light diffusion layer is not lost, but generally silicate glass, phosphate glass, borate glass, etc. And oxide glass.

  Moreover, as a polymer resin used as a transparent binder, a polyester resin, an acrylic resin, an acrylic urethane resin, a polyester acrylate resin, a polyurethane acrylate resin, an epoxy acrylate resin, a urethane resin, an epoxy resin, Polycarbonate resin, cellulose resin, acetal resin, vinyl resin, polyethylene resin, polystyrene resin, polypropylene resin, polyamide resin, polyimide resin, melamine resin, phenol resin, silicone resin, fluorine resin A thermoplastic resin such as a resin, a thermosetting resin, an ionizing radiation curable resin, or the like can be used.

  As the spherical fine particles, inorganic fine particles such as silica, alumina, talc, zirconia, zinc oxide and titanium dioxide, and organic fine particles such as polymethyl methacrylate, polystyrene, polyurethane, benzoguanamine and silicone resin can be used. In particular, organic fine particles are preferable in that a spherical shape can be easily obtained.

  The particle diameter of the spherical fine particles is preferably 1 μm to 10 μm as an average particle diameter, and more preferably 2 μm to 6 μm. By setting the average particle size in such a range, the haze of JIS K7105: 1981 is set to 60% or more, and a light diffusion layer having a tristimulus value Y of 10 or less in the reflection method of JIS Z8722: 2000 is used. It is possible to reduce the amount of light diffused backward with respect to the traveling direction of light (back diffused light) while having high diffusibility. As a result, when ambient light other than the image light from the projector is incident on the light diffusion layer, the backward diffused light can be reduced, so that the dark display portion of the projector image becomes bright even in projection under a bright environment. It is possible to project an image with higher contrast.

  The particle size distribution of the spherical fine particles is not particularly limited as long as the average particle size is in the above range, and may be monodispersed or polydispersed, but further reduces the back diffused light. From the viewpoint of achieving this, monodispersed ones are preferred.

  Further, regarding the refractive index of the spherical fine particles and the transparent binder, a value obtained by dividing the refractive index of the spherical fine particles by the refractive index of the transparent binder is 0.91 or more and 1.09 or less (however, excluding 1.00). Is preferred. By setting the value obtained by dividing the refractive index of the spherical fine particle by the refractive index of the transparent binder in such a range, the haze of JIS K7105: 1981 is set to 60% or more, and the reflection method of JIS Z8722: 2000 A light diffusing layer having a stimulation value Y of 10 or less can be obtained, and back diffusion light can be reduced while having high diffusibility. As a result, when ambient light other than the image light from the projector is incident on the light diffusion layer, the backward diffused light can be reduced, so that the dark display portion of the projector image becomes bright even in projection under a bright environment. It is possible to project an image with higher contrast.

  Further, the content of the spherical fine particles in the light diffusing layer and the thickness of the light diffusing layer cannot be unconditionally defined by the refractive index of the spherical fine particles and the refractive index of the transparent binder, but the average particle diameter of the spherical fine particles is within the above range ( 1 μm to 10 μm), and a combination of materials in which the value obtained by dividing the refractive index of the spherical fine particles by the refractive index of the transparent resin binder is in the above range (0.91 to 1.09, except 1.00) And the content and the light diffusion layer thickness may be adjusted so that the haze in JIS K7105: 1981 is 60% or more. By setting the haze to 60% or more, the reflected light of the image projected from the projector can be appropriately diffused and the viewing angle can be sufficiently widened. Further, by setting the total light transmittance in JIS K7361-1: 1997 to 70% or more, light incident from the projector can be efficiently transmitted to the reflection layer, so that the image can be projected brighter.

  The light diffusion layer as described above preferably has a substantially smooth surface. In the present invention, being substantially smooth means that the arithmetic average roughness (Ra) in JIS B0601: 2001 is 0.30 μm or less, preferably 0.15 μm or less. By setting it as such a range, a backscattered light can be reduced, the fall of contrast can be suppressed, and it can be set as a more easy-to-see screen.

  Moreover, the reflection type screen of the present invention as described above may be provided with an antireflection layer as the uppermost layer. As a result, it is possible to prevent a decrease in the amount of light of the image projected from the projector, project a brighter image on the screen, reduce reflection, and make the screen easier to see.

  Further, the surface may be provided with fine irregularities for preventing reflection so that Y of the tristimulus value in the reflection method of JIS Z8722: 2000 is 10 or less. Thereby, it is possible to reduce the difficulty in viewing the image due to the reflection while minimizing the decrease in contrast.

  The reflective screen of the present invention may be provided with a hard coat layer as the uppermost layer. As a result, it is possible to prevent display quality from being deteriorated due to scratches on the screen surface.

  As described above, the reflective screen of the present invention has light reflectivity with respect to light in the blue, green, and red wavelength regions, and each average reflectance of the light in the wavelength regions is in the visible wavelength region. The reflective screen has a reflection layer higher than the average reflectance of light outside the wavelength region, and the reflective screen has fine particles and transparent on the incident surface side with respect to the reflection layer that reflects the light in each wavelength region. Having at least one light diffusing layer composed of a binder, fine particles contained per unit area of the light diffusing layer located on the incident surface side of each reflecting layer that reflects light in each wavelength region, Since the total scattering cross-sections at the respective central wavelengths in the respective wavelength regions are substantially the same, a high-contrast image is displayed and an image with high image color reproducibility is displayed. It can be projected with little image color change picture when viewed over emissions from a diagonal position.

  Hereinafter, the present invention will be described in more detail based on examples. In this example, “parts” and “%” are based on weight unless otherwise specified.

[Example 1]
A coating solution for a light diffusion adhesive layer having the following formulation was prepared. The scattering cross section Q of one particle at the center wavelength in the B, G, R wavelength region by this combination is 3.57 × 10 ⁻¹² m ² , 2.51 × 10 ⁻¹² m ² , 2.01 respectively. × 10 ^-12 m ² Therefore, the reflective layers are arranged in the order of B, G, and R reflective layers from the incident surface side. The number of particles per unit volume when this coating solution is applied and dried is 3.41 × 10 ¹⁶ particles / m ³ .

  On a black film (Lumirror X30: Toray Industries, Inc.) having a thickness of 100 μm, an adhesive layer coating solution having the following formulation was applied and dried to form an adhesive layer having a thickness of 10 μm, and Teijin Tetron MFL-19 as a red wavelength region reflective layer 0.0 (Teijin DuPont Films) was laminated.

  Next, a light diffusing adhesive layer coating solution having the following formulation was applied and dried to form a 10.5 μm thick light diffusing adhesive layer. Teijin Tetron MFL-16.5 (Teijin DuPont Film as a green wavelength region reflective layer) Were laminated.

  In the same manner, a light diffusion adhesive layer having a thickness of 12.7 μm was formed, and Teijin Tetron MFL-13.0 (Teijin DuPont Films Ltd.) was laminated as a blue wavelength region reflective layer.

  The same light diffusion adhesive layer coating solution is applied to a 75 μm thick transparent substrate (Lumirror T60: Toray Industries, Inc.) and dried to form a light diffusion adhesive layer with a thickness of 30 μm. The reflective screen of Example 1 was obtained by sticking.

  The thicknesses of the light diffusing adhesive layers with respect to the B, G, and R reflecting layers are 30 μm, 42.7 μm, and 53.2 μm, respectively.

  In addition, in the case of laminating all the light diffusing adhesive layers corresponding to each of the reflection layers of B, G, and R, the haze is 93.1%, the total light transmittance is 95.0%, and the tristimulus values in the reflection method Y of 6.8 was 6.8. In addition, the total scattering cross section per unit area at the center wavelength in the B, G, and R wavelength regions was 3.65. Further, the value obtained by dividing the refractive index of the spherical fine particles by the refractive index of the transparent binder was 0.96.

<Prescription of coating liquid for light diffusion adhesive layer of Example 1>
・ 100 parts of transparent binder (urethane adhesive) (refractive index 1.50, solid content 50%)
(Takelac A-971: Takeda Pharmaceutical Company Limited)
・ Isocyanate curing agent (solid content: 75%) 7.6 parts (Takenate A-3: Takeda Pharmaceutical Company Limited)
・ Spherical fine particles (silicone resin) 11.1 parts (refractive index 1.44, average particle size 2.0 μm)
(Tospearl 120: GE Toshiba Silicone)
・ Methyl ethyl ketone 15.8 parts ・ Toluene 15.8 parts

<Prescription of coating liquid for adhesive layer of Example 1>
・ Acrylic adhesive (solid content 40%) 100 parts (Olivein BPS1109: Toyo Ink Co., Ltd.)
・ Isocyanate curing agent (solid content 38%) 2.4 parts (Olivein BHS8515: Toyo Ink Co., Ltd.)
・ 100 parts of ethyl acetate

[Example 2]
A coating solution for a light diffusion adhesive layer having the following formulation was prepared. The scattering cross section Q of one particle at the center wavelength in the B, G, R wavelength region by this combination is 4.56 × 10 ⁻¹¹ m ² , 6.16 × 10 ⁻¹¹ m ² , 7.65, respectively. × 10 ^-11 m ² Therefore, the reflective layers are arranged in the order of R, G, and B reflective layers from the incident surface side. Further, the number of particles per unit volume when this light diffusion adhesive layer coating solution is applied and dried is 6.29 × 10 ¹⁴ particles / m ³ .

  On the black film (Lumirror X30: Toray Industries, Inc.) having a thickness of 100 μm, the adhesive layer coating solution of Example 1 was applied and dried to form an adhesive layer having a thickness of 10 μm. As a blue wavelength region reflective layer, Teijin Tetron MFL- 13.0 (Teijin DuPont Films) was laminated.

  Next, a light diffusing adhesive layer coating solution having the following formulation was applied and dried to form a light diffusing adhesive layer having a thickness of 21.9 μm, and Teijin Tetron MFL-16.5 (Teijin DuPont Film as a green wavelength region reflecting layer) Were laminated.

  Similarly, a 12.1 μm thick light diffusion adhesive layer was formed, and Teijin Tetron MFL-19.0 (Teijin DuPont Films) was laminated as a red wavelength region reflective layer.

  Further, the same light diffusion layer coating solution is applied to the same transparent substrate as in Example 1 and dried to form a light diffusion adhesive layer having a thickness of 50 μm, which is adhered to the red wavelength region reflective layer described above. A reflective screen of Example 2 was obtained.

  The thicknesses of the diffusion adhesive layers with respect to the reflection layers of B, G, and R are 84 μm, 62.1 μm, and 50 μm, respectively.

  In addition, in the case where all of the light diffusion adhesive layers corresponding to each of the reflection layers of B, G, and R are laminated, the haze is 92.3%, the total light transmittance is 93.0%, and the tristimulus values in the reflection method Y of 5.9 was 5.9. In addition, the total scattering cross section per unit area at the center wavelength in the B, G, and R wavelength regions was 2.41. Further, the value obtained by dividing the refractive index of the spherical fine particles by the refractive index of the transparent binder was 1.06.

<Prescription of coating liquid for light diffusion adhesive layer of Example 2>
・ 100 parts of transparent binder (urethane adhesive) (refractive index 1.50, solid content 50%)
(Takelac A-971: Takeda Pharmaceutical Company Limited)
・ Isocyanate curing agent (solid content: 75%) 7.6 parts (Takenate A-3: Takeda Pharmaceutical Company Limited)
・ 4.5 parts of spherical fine particles (polystyrene resin) (refractive index of 1.59, average particle diameter of 6.0 μm)
(Techpolymer SBX-6: Sekisui Plastics Co., Ltd.)
・ 100 parts of ethyl acetate

[Example 3]
Light diffusion adhesive layer coating solutions 1 and 2 having the following formulation were prepared. The scattering cross section Q of one particle at the center wavelength in the B, G, R wavelength region by this combination is 4.04 × 10 ⁻¹¹ m ² , 3.23 × 10 ⁻¹¹ m ² , 3.81, respectively. × 10 ^-11 m ² Therefore, the reflective layers are in the order of the B, R, and G reflective layers from the incident surface side. In addition, when these coating solutions 1 and 2 are applied and dried, the number of particles per unit volume is 1.09 × 10 ¹⁵ particles / m ³ and 2.87 × 10 ¹⁴ particles / m ³ , respectively.

  On the black film (Lumirror X30: Toray Industries, Inc.) having a thickness of 100 μm, the adhesive layer coating solution of Example 1 was applied and dried to form an adhesive layer having a thickness of 10 μm. Teijin Tetron MFL- 16.5 (Teijin DuPont Films) was laminated.

  Next, the light diffusion adhesive layer coating liquid 2 having the following formulation was applied and dried to form a light diffusion adhesive layer having a thickness of 29.2 μm, and Teijin Tetron MFL-19.0 (Teijin DuPont) was used as a red wavelength region reflective layer. Film).

  Similarly, the light diffusion adhesive layer coating solution 2 was applied and dried to form a light diffusion adhesive layer having a thickness of 9.1 μm. Teijin Tetron MFL-13.0 (Teijin DuPont Films Ltd.) was used as the blue wavelength region reflective layer. ).

  Next, the light diffusing layer coating solution 1 is applied to the same transparent substrate as in Example 1 and dried to form a light diffusing adhesive layer having a thickness of 40 μm and adhered to the blue wavelength region reflective layer described above. Thus, a reflective screen of Example 3 was obtained.

  The thicknesses of the diffusion adhesive layers with respect to the reflection layers of B, G, and R are 40 μm, 78.3 μm, and 49.1 μm, respectively.

  In the case of laminating all the light diffusing adhesive layers corresponding to each of the reflection layers of B, G, and R, the haze is 83.6%, the total light transmittance is 90.8%, and the tristimulus values in the reflection method Y of 5.0 was 5.0. The total scattering cross section per unit area at the center wavelength in the B, G, and R wavelength regions was 1.76. Further, the value obtained by dividing the refractive index of the spherical fine particles by the refractive index of the transparent binder was 1.09.

<Prescription of Coating Solution 1 for Light Diffusing Adhesive Layer of Example 3>
・ 100 parts of transparent binder (acrylic adhesive) (refractive index 1.47, solid content 40%)
(Olivein BPS1109: Toyo Ink Manufacturer)
・ Isocyanate curing agent (solid content 38%) 2.4 parts (Olivein BPS8515: Toyo Ink Co., Ltd.)
・ Spherical fine particles (polystyrene resin) 3.3 parts (refractive index 1.60, average particle size 5.0 μm)
(Chemisnow SX-500: Soken Chemical)
・ 100 parts of ethyl acetate

<Prescription of Coating Solution 2 for Light Diffusing Adhesive Layer of Example 3>
・ 100 parts of transparent binder (acrylic adhesive) (refractive index 1.47, solid content 40%)
(Olivein BPS1109: Toyo Ink Manufacturer)
・ Isocyanate curing agent (solid content 38%) 2.4 parts (Olivein BPS8515: Toyo Ink Co., Ltd.)
・ Spherical fine particles (polystyrene resin) 0.8 parts (refractive index 1.60, average particle diameter 5.0 μm)
(Chemisnow SX-500: Soken Chemical)
・ 100 parts of ethyl acetate

[Comparative Example 1]
In the same manner as in Example 1, the reflective layer was laminated on the black film in the order of R, G, and B using only the adhesive layer coating solution of Example 1. Next, the light diffusion adhesive layer coating solution of Example 1 was applied to a transparent substrate similar to Example 1, dried to form a 30 μm thick light diffusion adhesive layer, and affixed to the above-described B wavelength region reflective layer. The reflective screen of Comparative Example 1 was obtained.

  The haze of the light diffusion layer was 92.3%, the total light transmittance was 94.5%, and the tristimulus value Y by the reflection method was 6.5. In addition, the total scattering cross sections per unit area at the central wavelength in the B, G, and R wavelength regions were 3.65, 2.57, and 2.06, respectively.

[Comparative Example 2]
In the same manner as in Example 2, a reflective layer was laminated on a black film in the order of B, G, and R using only the adhesive layer coating solution of Example 1. Next, the light diffusion adhesive layer coating solution of Example 2 was applied to a transparent substrate similar to that of Example 2, dried to form a 50 μm thick light diffusion adhesive layer, and applied to the R wavelength region reflective layer described above. A reflective screen of Comparative Example 2 was obtained.

  The haze of the light diffusion layer was 90.9%, the total light transmittance was 92.7%, and the tristimulus value Y by the reflection method was 5.4. Moreover, the total scattering cross sections per unit area at the center wavelength in the wavelength regions of B, G, and R were 1.43, 1.94, and 2.41, respectively.

[Comparative Example 3]
In the same manner as in Example 3, a reflective layer was laminated on a black film in the order of G, R, and B using only the adhesive layer coating solution of Example 1. Next, as in Example 3, the light diffusion adhesive layer coating solution 1 of Example 3 was applied to a transparent substrate having a thickness of 75 μm and dried to form a light diffusion adhesive layer with a thickness of 40 μm. A reflective screen of Comparative Example 3 was obtained by sticking to the reflective layer.

  The light diffusing layer had a haze of 82.7%, a total light transmittance of 90.6%, and a tristimulus value Y by the reflection method of 5.0. Moreover, the total scattering cross sections per unit area at the center wavelength in the wavelength regions of B, G, and R were 1.76, 1.40, and 1.66, respectively.

  Regarding haze and total light transmittance in the above Examples and Comparative Examples, haze is based on JIS K7105: 1981, and total light transmittance is based on JIS K7361-1: 1997. Turbidimeter NDH2000 (Nippon Denshoku Industries Co., Ltd.) It was measured by. Further, Y of the tristimulus value by the reflection method in the above examples and comparative examples is a reflection method using a colorimetric illuminant ZE2000 (Nippon Denshoku Industries Co., Ltd.) as a C light source based on JIS Z8722: 2000. It was measured. The geometric condition for illumination and light reception of ZE2000 is condition d. Since the measurement sample has high light transmittance, transmitted light during measurement by the reflection method was not affected.

  Next, an image is projected on the reflective screens obtained in the examples and comparative examples using a liquid crystal projector (XV-P3: Sharp Corporation), and image color reproducibility and contrast under illumination of a fluorescent lamp are evaluated. Went. The results are shown in Table 1.

(1) Image color reproducibility The projector was turned on in an all white state, and the color coordinates at the center of the screen were measured from a position of 60 degrees obliquely from the front and the front. The measured value at the oblique position was the average of the left and right values. The color coordinates were measured with a colorimetric color difference meter CS-100 (Konica Minolta). The field of view of CS-100 is a two-degree field of view.

(2) Contrast As a result of visual evaluation of the projector image from the front while changing the illuminance of the fluorescent lamp, “も の” is the one with high contrast and good visibility even in a bright state where the illuminance is 1000 lx or more. The illuminance is the illuminance at the center of the screen when the projector is not projected.

  The reflective screens of Examples 1 to 3 have light reflectivity with respect to light in the blue, green, and red wavelength regions, and the average reflectance of the light in the wavelength regions is the above in the visible wavelength region. The reflective screen has a reflective layer higher than the average reflectance of light outside the wavelength region, and the reflective screen includes fine particles and a transparent binder on the incident surface side of the reflective layer that reflects the light in each wavelength region. Each wavelength of the fine particles contained per unit area of the light diffusing layer located on the incident surface side with respect to each reflecting layer reflecting at least one light diffusing layer and reflecting light in each wavelength region Since the total scattering cross-sections at the central wavelengths of each region are substantially the same, a high contrast image and a high image color reproducibility are displayed even in a bright environment. Especially color change picture when viewed screen from an oblique position has become what can be projected a little picture.

  On the other hand, the reflective screens of Comparative Examples 1 to 3 have light reflectivity with respect to light in the blue, green, and red wavelength regions, and the average reflectance of the light in the wavelength regions is within the visible wavelength region. In which the haze in JIS K7105: 1981 is 60% or more, and the total in JIS K7361-1: 1997 is closer to the incident surface side than the reflective layer. Since it has a light diffusion adhesive layer having a light transmittance of 70% or more and a tristimulus value Y of 10 or less in the reflection method of JIS Z8722: 2000, the projector image hardly generates back diffuse light of ambient light. The brightness of the dark display area did not increase, and a high contrast image could be projected. However, the total scattering interruption of the fine particles contained per unit area of the light diffusion layer located on the incident surface side with respect to each reflection layer that reflects the light in each wavelength region at each central wavelength in each wavelength region. Since the areas were not substantially the same, the color change of the image occurred when the screen was viewed from an oblique position.

The figure explaining the method of producing the light-diffusion layer of this invention B for the geometric cross-sectional area of the spherical particles ^{S (= πD 2/4)} , G, the ratio of the scattering cross section Q at the center wavelength of R each wavelength region (= Q / S), an example of a change with respect to particle size D FIG. Sectional drawing which shows one Example of the reflection type screen of this invention. Sectional drawing which shows the other Example of the reflection type screen of this invention. Sectional drawing which shows the other Example of the reflection type screen of this invention. Sectional drawing which shows the other Example of the reflection type screen of this invention. Sectional drawing which shows one Example of the reflection type screen of this invention and patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Reflective layer 3 ... Light diffusion layer 4 ... Light absorption layer 5 ... Adhesive layer 6 ... ..... reflective screen 21 ... first reflective layer 22 ... second reflective layer 23 ... third reflective layer 31 ... first light Diffusion layer 32... Second light diffusion layer 33... Third light diffusion layer

Claims (12)

Each of the light in the wavelength region has light reflectivity with respect to light in a blue wavelength region (420 nm to 480 nm) , a green wavelength region (520 nm to 580 nm), and a red wavelength region (590 nm to 650 nm) . A reflective screen having a reflective layer having an average reflectance higher than the average reflectance of light outside the wavelength region in the visible wavelength region,
The reflective screen, the on the incident surface side of the reflecting layer for reflecting light of each wavelength region, has a plurality of light diffusion layer made of the fine particles and a transparent binder, the light diffusion layer is identical to the same particles It consists of a transparent binder, the fine particles have an average particle diameter of 2 μm to 10 μm, and a value obtained by dividing the refractive index of the fine particles by the refractive index of the transparent binder is 0.91 to 1.09 (excluding 1.00) ) And
The total scattering cross section at the center wavelength of each wavelength region of the fine particles included per unit area of the light diffusion layer located on the incident surface side of the reflection layer that reflects the light of each wavelength region is the smallest A reflective screen characterized in that the largest one is within 120% with reference to . Each of the light in the wavelength region has light reflectivity with respect to light in a blue wavelength region (420 nm to 480 nm) , a green wavelength region (520 nm to 580 nm), and a red wavelength region (590 nm to 650 nm) . A reflective screen having a reflective layer having an average reflectance higher than the average reflectance of light outside the wavelength region in the visible wavelength region,
The reflective screen, the on the incident surface side of the reflecting layer for reflecting light of each wavelength region, has a plurality of light diffusion layer made of the fine particles and a transparent binder, the light diffusion layer is identical to the same particles It consists of a transparent binder, the fine particles have an average particle diameter of 2 μm to 10 μm, and a value obtained by dividing the refractive index of the fine particles by the refractive index of the transparent binder is 0.91 to 1.09 (excluding 1.00) ) And
The total scattering cross section at the center wavelength of the blue wavelength region of the fine particles contained per unit area of the light diffusion layer located on the incident surface side of the reflection layer that reflects light in the blue wavelength region, and the green wavelength The total scattering cross section at the center wavelength of the green wavelength region and the light in the red wavelength region of the fine particles contained per unit area of the light diffusing layer located on the incident surface side of the reflecting layer that reflects the light in the region The total scattering cross section at the center wavelength of the red wavelength region of the fine particles contained per unit area of the light diffusion layer located on the incident surface side of the reflecting layer that reflects the light is the largest on the basis of the smallest A reflective screen characterized in that the content is within 120% .   The reflective layer having light reflectivity with respect to light in the blue, green, and red wavelength regions includes three reflective layers that reflect light in each of the blue, green, and red wavelength regions. Item 3. The reflective screen according to Item 1 or 2. Each of the light in the wavelength region has light reflectivity with respect to light in a blue wavelength region (420 nm to 480 nm) , a green wavelength region (520 nm to 580 nm), and a red wavelength region (590 nm to 650 nm) . A reflective screen having a reflective layer having an average reflectance higher than the average reflectance of light outside the wavelength region in the visible wavelength region,
The reflective screen has at least one light diffusion layer composed of fine particles and a transparent binder on the incident surface side of the reflective layer that reflects the light in each wavelength region,
The total scattering cross section at the center wavelength of each wavelength region of the fine particles included per unit area of the light diffusion layer located on the incident surface side of the reflection layer that reflects the light of each wavelength region is the smallest The largest one based on is within 120% ,
The reflective layer is composed of three reflective layers that reflect light in each of the blue, green, and red wavelength regions, and the scattering interruption of one particle in the light diffusion layer at each central wavelength in each wavelength region. A reflection type screen, wherein a reflection layer having a large wavelength region is provided on the incident surface side.   The light diffusion layer is located further on the incident surface side of the reflective layer located closest to the incident surface side, and between the reflective layer located closest to the incident surface side and the reflective layer located second from the incident surface side, 5. The reflective screen according to claim 4, wherein the reflective screen is located between the second reflective layer and the third reflective layer from the incident surface side. 6. The reflective screen according to claim 4 , wherein a plurality of light diffusion layers are provided, and each light diffusion layer is made of the same fine particles and the same transparent binder. The plurality of light diffusion layers are characterized in that the layer thickness or the content of fine particles is adjusted in accordance with the size of the scattering cross section of each fine particle at each central wavelength in each wavelength region. Item 7. The reflective screen according to any one of Items 1 to 6 .   The reflective screen according to any one of claims 1 to 7, wherein the reflective layer is made of a transparent polymer resin.   The reflective screen according to claim 8, wherein the reflective layer is formed by a multilayer extrusion method.   The reflective screen according to claim 1, further comprising a light absorption layer that absorbs light transmitted through the reflection layer on a surface different from the incident surface side of the reflection layer.   A laminate in which all the light diffusion layers are laminated has a haze of 60% or more in JIS K7105: 1981, a total light transmittance of 70% or more in JIS K7361-1: 1997, and a tristimulus in the reflection method of JIS Z8722: 2000. The reflective screen according to claim 1, wherein the value Y is 10 or less.   The reflective screen according to claim 1, wherein the fine particles are spherical fine particles.

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