JP4552733B2 - Screen and manufacturing method thereof - Google Patents

Description

  The present invention relates to a screen that displays an image using projected light, and more particularly to a reflective screen and a method for manufacturing the same.

  In recent years, data projectors are widely used as a means for presenters to present materials in conferences and the like, and video projectors and movie film projectors are becoming popular in general households. In these projector apparatuses, light output from a light source is spatially modulated by a light valve to be image light, and this image light is projected onto a projection screen through an illumination optical system such as a lens. .

  Some projectors of this type can display a color image, and emit white light including three primary colors red (Red = R), green (Green = G), and blue (Blue = B) as a light source. A lamp is used, and a transmissive liquid crystal panel is used as a light valve. In this projector, white light emitted from the light source is separated into light beams of each color of red light, green light, and blue light by the illumination optical system, and these light beams are converged on a predetermined optical path. These light beams are spatially modulated by the liquid crystal panel in accordance with the image signal, the modulated light beams are combined as color image light by the light combining unit, and the combined color image light is enlarged and projected onto the screen by the projection lens.

  Recently, as a projector capable of displaying a color image, a narrow band three primary color light source, for example, a laser oscillator that emits narrow band light of each of the three primary colors is used as a light source, and a diffraction grating type light valve (GLV: Grating) is used as a light valve. Devices using light valves have been developed. In this projector, the light beams of the respective colors emitted from the laser oscillator are spatially modulated by the GLV in accordance with the image signal. The light beam thus modulated is combined as color image light by the light combining unit in the same manner as the projector device described above, and the combined color image light is enlarged and projected onto the screen by the projection lens.

  For such projectors, screens for displaying projected images are roughly classified into transmission types and reflection types. The transmissive screen transmits image light projected from the projector behind the screen so that the projected image can be seen by the transmitted light. The reflective screen is an image projected from the projector in front of the screen. The projection image can be seen by reflected light and reflected light.

  As the reflective screen, a bead screen or a white screen that reflects and scatters the projection light from the projector is used, but such a screen also reflects light other than the projection light, that is, external light, Since the black level (black video brightness) increases with the level, only images with a low contrast (= white level / black level) can be displayed under bright light with a high external light level. It was necessary to lower.

  On the other hand, a screen has been proposed in which a light absorbing layer is provided in front of a reflective layer to reduce the black level and improve the contrast under external light (see, for example, Patent Document 1). However, in this case, not only the outside light but also the projection light is reduced by the light absorption layer, so the white level is lowered, the screen gain (brightness) is lowered, and there is a limit to improving the contrast under bright light.

Further, as shown in FIG. 26, a transparent layer 103 having a plurality of protrusions 102 is provided on the diffusion plate 101 on the screen surface, and an opaque layer 104 made of black paint is provided on the side surface of each protrusion, so that the periphery can be removed. There has been proposed a screen that absorbs incident external light and improves contrast under external light without lowering the white level (see, for example, Patent Document 2). However, in this case as well, external light incident from the front of the screen is not absorbed, there is a limit to improving the contrast under bright light, and it takes time and effort to form protrusions and opaque layers on the side surfaces of the protrusions. there were.
Japanese Patent No. 3103802 Japanese Patent No. 2889153

As described above, with the conventional technology, it has been difficult to obtain a high-brightness and high-contrast screen that can display a bright and clear image under bright light with a high external light level.
The present invention has been made in view of this point, and an object of the present invention is to provide a screen capable of realizing high brightness and high contrast under bright light without having a complicated structure, and a method for manufacturing the same.

In order to solve the above-described problem, the first invention provides:
In a screen that displays an image by projected light,
An optical multilayer film composed of a plurality of metal oxide films and a light-absorbing thin film having transparency, and a reflective layer that reflects the transmitted light of the optical multilayer film, and for light in a specific wavelength region corresponding to the projection light A selective reflection layer having reflection characteristics and having absorption characteristics for light in a wavelength region excluding a specific wavelength region;
A diffusion layer for scattering the reflected light of the selective reflection layer;
An adhesive layer that bonds the selective reflection layer and the diffusion layer together,
The metal oxide film immediately above the reflective layer has a wavelength range of absorption characteristics between the wavelength of the emission line peak of the red component and the wavelength of the emission line peak of the green component, and between the wavelength of the emission line peak of the green component and the wavelength of the blue component. The refractive index and / or the film thickness is adjusted to be between the wavelengths of the emission line peak,
The pressure-sensitive adhesive layer absorbs light in the green wavelength region,
The adhesive layer has the highest light transmittance in the red wavelength region, which is one of a plurality of specific wavelength regions that exhibit high reflection characteristics in the selective reflection layer, and a plurality of specific indications that exhibit high reflection characteristics in the selective reflection layer. The screen is characterized in that the transmittance of light in the green wavelength region, which is one of the wavelength regions, is the lowest.
The second invention is
In a screen that displays an image by projected light,
An optical multilayer film composed of a plurality of metal oxide films and a light-absorbing thin film having transparency, and a reflective layer that reflects the transmitted light of the optical multilayer film, and for light in a specific wavelength region corresponding to the projection light A selective reflection layer having reflection characteristics and having absorption characteristics for light in a wavelength region excluding a specific wavelength region;
A diffusion layer that scatters the reflected light of the selective reflection layer, and
The metal oxide film immediately above the reflective layer has a wavelength range of absorption characteristics between the wavelength of the emission line peak of the red component and the wavelength of the emission line peak of the green component, and between the wavelength of the emission line peak of the green component and the wavelength of the blue component. The refractive index and / or the film thickness is adjusted to be between the wavelengths of the emission line peak,
The diffusion layer absorbs light in the green wavelength region,
The diffusion layer has the highest light transmittance in the red wavelength region, which is one of a plurality of specific wavelength regions that exhibit high reflection characteristics in the selective reflection layer, and a plurality of specific indications that exhibit high reflection characteristics in the selective reflection layer. The screen is characterized in that the transmittance of light in the green wavelength region, which is one of the wavelength regions, is the lowest.

  In the first and second inventions, light in a specific wavelength region corresponding to the projection light is reflected from the light incident on the selective reflection layer composed of the optical multilayer film and the reflection layer, and the other wavelength regions Light is absorbed. As a result, it is possible to reduce the black level due to the outside light almost without lowering the white level due to the projection light, and a screen with high brightness and high contrast can be obtained under bright light.

  The reflection layer used for the selective reflection layer is, for example, a metal substrate, a metal film formed on the substrate, or a metal film formed on an optical multilayer film. The metal material is preferably Al, Nb, and Any metal or alloy of Ag is used. In the case of a metal film, a thickness that does not allow light to pass through is required, and is preferably 50 nm or more.

The optical multilayer film is formed by laminating a plurality of metal oxide films and at least one light-absorbing thin film having transparency. The metal oxide film is, for example, a dielectric film made of Nb ₂ O ₅ , TiO ₂ , Ta ₂ O ₅ , Al ₂ O ₃ or SiO ₂ , or In ₂ O ₃ , SnO ₂ , ZnO, In ₂ O ₃ − A conductive film made of a SnO ₂ compound or a material in which any of these is doped with a metal is used. A thermosetting resin that is transparent in the visible wavelength region can also be used.
Here, the metal oxide film is designed according to the refractive index of the metal oxide film and the wavelength region to be reflected, that is, the specific wavelength region, but the metal oxide film other than the metal oxide film directly above the reflective film is reflective. The refractive index and / or the film thickness may be adjusted in order to balance the chromaticity of the light.

  As the specific wavelength region, the main component wavelength region of the projection light, for example, the RGB primary color wavelength region is selected. In addition, when the intensity of each color light of RGB is different in the light source of the projection light, the intensity of each color light of RGB is adjusted by adjusting the reflection intensity of each color light of RGB of the selective reflection layer according to the film configuration and film thickness design of the optical multilayer film. It is also possible to correct the color deviation of the image due to variations.

The light-absorbing thin film having transparency is formed of a material having a refractive index of 1 or more and an absorption coefficient of 0.5 or more. Examples of such materials include Nb, Nb-based alloys, C, Cr, Fe, Ge, Ni, Pd, Pt, Rh, Ti, TiN, TiN _x W _y , Mn, Ru, and PbTe. The film thickness is preferably in the range of 2 to 20 nm. If it is less than 2 nm, the intended light absorption cannot be obtained, and if it exceeds 20 nm, the necessary transparency may be impaired.

In order to display an image with good visibility, it is preferable that a diffusion layer that scatters reflected light is formed on the selective reflection layer. Here, it is more preferable to provide a pressure-sensitive adhesive layer containing a dye that joins both the diffusion layer and the selective reflection layer and absorbs light in the specific wavelength region, and the pressure-sensitive adhesive layer further includes a black dye. It is particularly preferable to contain
Further, instead of the diffusion layer, a plurality of convex portions or concave portions having a diffusion structure may be provided on the substrate surface, and a selective reflection layer having a uniform film thickness may be formed thereon.

The third invention is
An optical multilayer film composed of a plurality of metal oxide films and a light-absorbing thin film having transparency, and a reflective layer that reflects the light transmitted through the optical multilayer film are formed, and has reflection characteristics for light in a specific wavelength region. And a selective reflection layer forming step that forms a selective reflection layer having absorption characteristics with respect to light in a wavelength region other than the specific wavelength region ,
Bonding the selective reflection layer and the diffusion layer through the pressure-sensitive adhesive layer,
In the selective reflection layer forming step, the wavelength region of the absorption characteristic is between the wavelength of the emission line peak of the red component and the wavelength of the emission line peak of the green component, and between the wavelength of the emission line peak of the green component and the emission line peak of the blue component. Including the step of setting the refractive index and / or film thickness of the metal oxide film immediately above the reflective layer so as to be between the wavelengths,
The pressure-sensitive adhesive layer absorbs light in the green wavelength region,
The pressure-sensitive adhesive layer has the highest light transmittance in the red wavelength region, which is one of a plurality of specific wavelength regions exhibiting high reflection characteristics in the selective reflection layer, and a plurality of light reflection characteristics in the selective reflection layer. The screen manufacturing method is characterized in that the transmittance of light in the green wavelength region which is one of the specific wavelength regions is the lowest.
The fourth invention is:
An optical multilayer film composed of a plurality of metal oxide films and a light-absorbing thin film having transparency, and a reflective layer that reflects the light transmitted through the optical multilayer film are formed, and has reflection characteristics for light in a specific wavelength region. And a selective reflection layer forming step that forms a selective reflection layer having absorption characteristics with respect to light in a wavelength region other than the specific wavelength region ,
Forming a diffusion layer on the selective reflection layer,
In the selective reflection layer forming step, the wavelength region of the absorption characteristic is between the wavelength of the emission line peak of the red component and the wavelength of the emission line peak of the green component, and between the wavelength of the emission line peak of the green component and the emission line peak of the blue component. Including the step of setting the refractive index and / or film thickness of the metal oxide film immediately above the reflective layer so as to be between the wavelengths,
The diffusion layer absorbs light in the green wavelength region,
The diffusion layer has the highest light transmittance in the red wavelength region, which is one of a plurality of specific wavelength regions that exhibit high reflection characteristics in the selective reflection layer, and a plurality of specific indications that exhibit high reflection characteristics in the selective reflection layer. The screen manufacturing method is characterized in that the transmittance of light in the green wavelength region, which is one of the wavelength regions, is the lowest.

  Here, in the selective reflection layer forming step, in order to balance the chromaticity of light reflected by the selective reflection layer, the refractive index and / or the film thickness of the metal oxide film other than the metal oxide film immediately above the reflection film. It is preferable to include a step of setting.

  According to the screen of the present invention, the selective reflection layer that reflects the light in the specific wavelength region and absorbs the other light is configured by the optical multilayer film and the reflection layer, thereby mainly reflecting the projection light. Thus, most of the outside light can be absorbed, and a screen with high brightness and high contrast can be realized under bright light. Further, by using a selective reflection layer in which the reflection intensity in each of the RGB color wavelength regions is adjusted, it is possible to provide an image with a color balance.

  According to the method for manufacturing a screen of the present invention, it has a reflection characteristic for light in a specific wavelength region, has an absorption characteristic for light in a wavelength region other than the specific wavelength region, and has high brightness and high brightness under bright light. A contrast screen can be easily obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of a screen according to the present invention, in which light on a specific wavelength region such as the RGB primary color wavelength region is reflected on a substrate 1 and light in other wavelength regions is absorbed. As the selective reflection layer 2, an optical multilayer film 4 including a metal film 3, a metal oxide film 4Di (i = 1, 2,...) And a light-absorbing thin film 4Mj (j = 1, 2,...) Having transparency. And a diffusion layer 5 that scatters the reflected light of the selective reflection layer 2 is formed thereon.

  The substrate 1 supports the screen, and various materials can be used. When it is desired to have flexibility as a screen, a plastic film having a thickness of, for example, a unit of 100 μm is used. Examples of such plastic materials include polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyolefin (PO), and the like.

  The selective reflection layer 2 is designed according to the wavelength region of the projection light, for example, the three primary color wavelength regions so as to mainly reflect the projection light from the projector and absorb the other wavelength region light. The wavelength region varies depending on the light source of the projector. Such a selective reflection layer 2 includes a metal film 3 and an optical multilayer film 4 including at least a metal oxide film 4D1 and a light-absorbing thin film 4M1 having transparency.

  The metal film 3 is formed as a reflective layer that reflects the light transmitted through the optical multilayer film 4, and is preferably a metal material having a substantially uniform reflectivity in the visible wavelength region, such as a metal such as Al, Ag, or Nb. Alternatively, an alloy (for example, an Al-based alloy such as AlSiCu or an Ag-based alloy such as AgPdCu) is used. The film thickness needs to be a thickness that does not transmit light, and is preferably 50 nm or more. Such a metal film 3 is formed on the substrate 1 using an evaporation method, a sputtering method, or the like.

The metal oxide film 4Di constituting the optical multilayer film 4 is, for example, Nb ₂ O ₅ (niobium pentoxide), TiO ₂ (titanium dioxide), Ta ₂ O ₅ (tantalum pentoxide), Al ₂ O ₃ (aluminum oxide). Or a transparent dielectric film such as SiO ₂ (silicon dioxide), or In ₂ O ₃ (indium oxide), SnO ₂ (tin oxide), ZnO (zinc oxide), In ₂ O ₃ —SnO ₂ compound (ITO), Alternatively, it is made of a transparent conductive film made of a metal-doped material (for example, ZnO: Al, ZnO: Ga, etc.), and is formed on the metal film 3 or the light absorption thin film 4Mj by using, for example, a sputtering method. A film is formed. The metal oxide film 4Di may be a resin film that is transparent in the visible wavelength region. In this case, it can be formed by a coating method using a thermosetting resin that is cured by heat or ultraviolet rays.

The light absorbing thin film 4Mj having transparency is formed of a material having a refractive index of 1 or more and an absorption coefficient of 0.5 or more. Examples of such materials include Nb, Nb-based alloys, C, Cr, Fe, Ge, Ni, Pd, Pt, Rh, Ti, TiN, TiN _x W _y , Mn, Ru, and PbTe. The film thickness is preferably in the range of 2 to 20 nm. If the thickness is less than 2 nm, sufficient light absorption cannot be obtained, and if it exceeds 20 nm, the light transmittance may not be obtained. The light absorbing thin film 4Mj is formed on the metal oxide film 4Di by using, for example, a sputtering method.

  The selective reflection layer 2 has, for example, a high reflection characteristic such as a reflectance of 60% or more with respect to light in the three primary color wavelength regions, and an absorptance with respect to light in wavelength regions other than the three primary color wavelength regions. Is designed so as to have a high absorption characteristic of 50% or more. Here, each film thickness of the metal oxide film 4Di is such that the thickness of each film is d, the refractive index of each film is n, and each wavelength of light to be reflected out of the light incident on the optical multilayer film. Assuming that λ, the optical thickness nd of each film is designed to satisfy the equation shown in Equation 1 for each wavelength λ.

(Equation 1)
nd = λ (α ± 1/4) (where α is a natural number)

In accordance with this equation, when designing so as to have a reflectance peak in each of the three primary color wavelength regions, that is, the three primary color wavelengths are set as λ in the metal oxide film 4Di, and the value of α is adjusted for each of the wavelengths of the three primary colors. When the thickness nd takes substantially the same value, the optical thickness nd results in the least common multiple at the three primary colors, so that the metal oxide film 4Di becomes a thick film. Further, by appropriately selecting the material of the metal oxide film 4Di, that is, the refractive index, it is possible to determine the required thickness of the thick film, and this metal oxide film 4Di alone satisfies the reflection of all the desired three primary wavelengths. As a result, the number of stacked optical multilayer films 4 can be reduced. For example, when the optical film thickness (nd) of the metal oxide film 4D1 immediately above the metal film 3 is 1000 or more (that is, d = 435 nm or more when the constituent material of the metal oxide film is Nb ₂ O ₅ (n = 2.3)). In the case of SiO ₂ (n = 1.46), d = 685 nm or more), the metal oxide film 4Di can have a reflectance peak in each of the three primary color wavelength regions with one layer of the metal oxide film 4D1. .

Further, for example, in a configuration in which a metal oxide film 4D1 made of Nb ₂ O ₅ and a light absorption thin film 4M1 made of Nb are sequentially laminated on the metal film 3 made of Al as shown in FIG. The selective reflection layer 2 having the optical characteristics as shown is obtained. This has a high reflectance of, for example, 80% or more with respect to light of the three primary color wavelength regions, and has a high absorption of, for example, 80% or more with respect to light in a wavelength region other than the light of the three primary color wavelength regions. In addition, it is designed to have a transmittance of, for example, approximately 0% with respect to light in the entire wavelength region. The thickness of the Al film (metal film 3) is 50 nm, and the Nb ₂ O ₅ film (metal oxide film 4D1). ) Is 539 nm, and the Nb film (light-absorbing thin film 4M1) is 6 nm. Here, the case where the wavelength region of red light (R) is around 642 nm, the wavelength region of green light (G) is around 532 nm, and the wavelength region of blue light (B) is around 457 nm is taken as an example. .

  By the way, in the configuration in which the metal film 3 is provided under the metal oxide film 4D1, the phase of the light incident on the optical multilayer film is reversed, and therefore the reflectance curve on the assumption of the metal oxide film alone is used. The reflectance peak becomes the absorption peak. Therefore, the position of the absorption peak as the wavelength region can be adjusted by using the equation (1). That is, each film thickness of the metal oxide film 4Di is such that the thickness of each film is d, the refractive index of each film is n, and each wavelength of light to be absorbed among the light incident on the optical multilayer film is λ. Then, the optical thickness nd of the metal oxide film can be designed from the viewpoint of bringing the absorption peak in the wavelength region of light that is desired to be excluded as an image such as external light as reflection (absorption) characteristics.

When designed to have an absorptivity peak in a wavelength region other than the three primary color wavelength regions according to the equation (1), that is, in the metal oxide film 4D1, λ is the wavelength of the emission line peak of the red component and the emission line peak of the green component. Between the wavelength of the green component and the wavelength of the emission line peak of the green component and the wavelength of the emission line peak of the blue component, and the wavelength of the emission line peak of the red component and the wavelength of the emission line peak of the green component Meanwhile, the value of α is adjusted for each wavelength between the wavelength of the emission line peak of the green component and the wavelength of the emission line peak of the blue component so that the optical thickness nd takes substantially the same value. Further, by appropriately selecting the material of the metal oxide film 4D1, that is, the refractive index, the required film thickness can be determined, and the wavelength of the bright line peak of the red component of the target projection light can be determined only by this metal oxide film 4D1. And the green component emission line peak wavelength, and the green component emission line peak wavelength and blue component emission line peak wavelength, the absorption at each wavelength is satisfied. For example, the wavelength between the emission line peak wavelength of the red component and the emission line peak wavelength of the green component of the projection light is 629 nm, and the wavelength between the emission line peak wavelength of the green component and the emission line peak wavelength of the blue component is 498 nm. When the constituent material of the metal oxide film 4D1 immediately above the metal film 3 is Nb ₂ O ₅ (n = 2.3), the film thickness d≈450 nm or d≈560 nm of the metal oxide film 4D1 is obtained. By forming the metal oxide film 4D1 with these film thicknesses, between the wavelength of the emission line peak of the red component and the wavelength of the emission line peak of the green component, the wavelength of the emission line peak of the green component and the emission line of the blue component. It becomes possible to make an absorption peak at each wavelength between the peak wavelengths. In setting the film thickness of the metal oxide film 4D1, the refractive index may be adjusted by selecting the constituent material.

Here, the selective reflection layer 2 is formed as an optical multilayer film 4 on an Al metal film 3, an Nb ₂ O ₅ (450 nm thickness) metal oxide film 4D1, an Nb (3 nm thickness) light absorption thin film 4M1, Nb. _{A structure in which 2} O ₅ (450 nm thick) metal oxide films 4D2 are sequentially stacked (sample 1) and a selective reflection layer 2 on an Al metal film 3 as an optical multilayer film 4 are made of Nb ₂ O ₅ (560 nm thick) metal oxide film 4D1, Nb (3 nm thick) light-absorbing thin film 4M1, and Nb ₂ O ₅ (560 nm thick) metal oxide film 4D2 (stack 2) The relationship between the incident angle of projector light and the color shift was investigated for each sample. Using a projector (HS50 manufactured by Sony Corporation) that uses a UHP lamp as a projector light source, white light from the projector is projected with the incident angles changed to 0, 40, and 50 degrees, and the reflected light is spectral radiance. The color coordinate xy was measured with a meter (PR650 manufactured by Photo Research). Next, after the color coordinate xy is converted into the color coordinate u′v ′ based on the CIE 1976 USC chromaticity diagram, the color difference according to the distance on the u′v ′ chromaticity diagram is calculated, and the incident angle is 0 degree according to the following formula: The color shift (ΔJND) from was determined.

(Equation 2)
ΔJND = (Δu ′ ² + Δv ′ ² ) ^2/1 /0.004

The results are shown in Table 1.
As the incident angle of the projector light increases, the color shift (ΔJND) of sample 2 becomes very large. On the other hand, in sample 1, the color shift is relatively small. Therefore, it can be seen that the film thickness of the metal oxide film 4D1 is preferably set to 450 nm with little color shift even when the observation angle of the screen is large.

Next, the reflection characteristic of the sample 1 is shown in FIG. As a result, it was suggested that the reflectance of the projection light in the blue wavelength region is relatively low, and the chromaticity balance is poor. Therefore, the chromaticity balance of the light reflected by the selective reflection layer 2 was adjusted by adjusting the refractive index and / or the film thickness of the metal oxide film 4D2. Specifically, the refractive index is determined by selecting the constituent material of the metal oxide film 4D2, and the chromaticity balance of the reflected light is the color of the reflected light of the reference screen (white screen) while changing the film thickness. The film thickness closest to the balance was examined. As a result, when the constituent material of the metal oxide film 4D2 was _Nb 2 _{O 5,} and the thickness thereof is 330 nm.

In FIG. 3B, an optical multilayer film 4 is formed on the Al metal film 3 as a metal oxide film 4D1 of Nb ₂ O ₅ (450 nm thickness), a light absorption thin film 4M1 of Nb (3 nm thickness), Nb ₂ O. ₅ shows a result of producing a sample (sample 3) having a structure in which metal oxide films 4D2 of ₅ (330 nm thickness) are sequentially laminated and measuring the reflection characteristics thereof. The absorptivity peak is set at a wavelength between the wavelength of the emission line peak of the red component and the wavelength of the emission line peak of the green component and the wavelength between the wavelength of the emission line peak of the green component and the wavelength of the emission line peak of the blue component. It can be seen that the reflectance in the blue wavelength region has been improved.

  For samples 1 and 3, white light was projected from a projector (HS50 manufactured by Sony Corporation) at an incident angle of 0, and the color coordinates xy of the reflected light were measured with a spectral radiance meter (PR650 manufactured by Photo Research). . Next, the color misregistration (ΔJND) of each sample was obtained according to the formula 2 using the color coordinates of the white light of the projector as a reference.

  The results are shown in Table 2. The color coordinate xy of the sample 3 is smaller than that of the sample 1, and by improving the reflectance of the selective reflection film 2 in the blue wavelength region, the reflected light can be shifted in the blue direction, and the color shift is also reduced. I was able to make it smaller.

  The selective reflection layer 2 having such a configuration has a high reflection characteristic with respect to light in the three primary color wavelength ranges and a high absorption characteristic with respect to light in a wavelength region other than the three primary color wavelength ranges, so that the external light level is low. Even in high environments, the white level of the screen remains high and the black level is kept low. In addition, since the optical multilayer film 4 constituting the selective reflection layer 2 has a small number of layers and a thin film thickness, a flexible screen can be created by using a flexible substrate.

  Further, in the present invention, by making the metal oxide film 4Di thick, the number of laminated layers as the optical multilayer film 4 can be reduced, and the adjustment of the film thickness of the metal oxide film 4Di is facilitated. There is an effect that it becomes easy to manufacture.

  Originally, when the metal oxide film 4Di is formed on a large area as a screen, the film thickness may deviate from the designed film thickness. However, the optical characteristic of the selective reflection layer 2 becomes a problem as a screen due to this film thickness deviation. there is a possibility. In the present invention, since the change in the optical characteristics due to the film thickness shift of the metal oxide film 4Di is large, the film thickness shift can be easily detected, and the film thickness can be corrected. Hereinafter, the detection method will be described.

FIG. 4 is a diagram showing the reflection characteristics at the stage where the metal oxide film 4D1 made of Nb ₂ O ₅ is formed on the metal film 3 (Al). In the figure, curve (a) shows the reflection characteristics when the thickness of the metal oxide film 4D1 is the designed thickness (450 nm), and has absorption peaks A, B, and C which are the bottoms of the reflectance. ing. Curve (b) shows the reflection characteristics when the metal oxide film 4D1 is 1% thicker than the designed film thickness, and curve (c) shows the reflection characteristics when the film thickness is 1% thinner than the designed film thickness.

  Here, the reflection characteristic curve tends to translate (shift) in the direction of the wavelength axis due to the variation in the thickness of the metal oxide film 4Di, and accordingly, the absorption peak is designed to be the thickness of the metal oxide film 4Di. When it is thinner than the film thickness, it shifts to the short wavelength side, and when it is thicker than the design film thickness, it shifts to the long wavelength side, and the shift amount is proportional to the magnitude of the film thickness deviation. Therefore, if the absorption peak corresponding to any of the absorption peaks A, B, and C in the curve (a) is monitored, it is possible to detect the film thickness deviation of the metal oxide film 4Di.

  For example, in FIG. 4, the position of the absorption peak B (wavelength of about 495 nm) on the curve (a) is confirmed in advance, and the reflection characteristics of the manufactured product are measured and compared with the position of the absorption peak corresponding to the absorption peak B. Thus, the presence or absence of a film thickness deviation of the metal oxide film 4D1 can be known. In addition, if the correlation between the film thickness deviation amount (difference between the actual film thickness and the designed film thickness) and the shift amount of the absorption peak is obtained in advance, the metal oxide film manufactured by simply measuring the position of the absorption peak The amount of 4Di film thickness deviation is known and correction is easy. FIG. 4 shows that detection can be made even with a film thickness deviation of 1% with respect to the design film thickness of the metal oxide film 4D1.

Further, when the film thicknesses of all the films are changed at the same ratio with reference to the thicknesses of the metal film 3, the metal oxide film 4D1, and the light absorption thin film 4M1 at this time, in each wavelength region of RGB, FIG. The reflectance changes as shown in (1) to (3). Further, when the incident angle with respect to the screen is changed, the reflectance changes as shown in (1) to (3) of FIG. 6 in each of the RGB wavelength regions. Here, as a comparative example, the film thickness dependence of the reflectance change of the selective reflection layer of the screen proposed by the same applicant as the present applicant in Japanese Patent Application No. 2002-070799 is shown in FIGS. In (6), the dependence of the change in reflectance on the incident angle is shown together with (4) to (6) in FIG. The selective reflection layer of the comparative example is an optical multilayer film in which a high refractive index layer (Nb ₂ O ₅ ) and a low refractive index layer (SiO ₂ ) are alternately stacked.

  As shown in FIGS. 5 and 6, the selective reflection layer 2 of the present embodiment has a smaller film thickness dependency than the comparative example, and therefore also a smaller incident angle dependency, so that a wide viewing angle characteristic can be obtained. .

The optical multilayer film in the selective reflection layer of the present embodiment has a minimum number of layers of two, but the number of layers can be further increased. For example, 50 nm on the metal film 3 having a thickness of Al, 534 nm metal oxide _Nb 2 _{O 5} of the light-absorbing thin film 4M1,534nm thick thick _Nb 2 _{O 5} metal oxide film 4D1,19nm thick Nb film 4D2 When the number of stacked optical multilayer films 4 is three, the optical characteristics shown in FIG. 7 are obtained. Compared with the configuration in which the optical multilayer film 4 shown in FIG. 2 has two layers, the half width of the reflection peak in the three primary color wavelength regions is reduced, and the black level of the screen can be further reduced.

Further, the number of laminated optical multilayer films 4 is five. On the 50 nm thick Al metal film 3, for example, a 551 nm thick Nb ₂ O ₅ metal oxide film 4D1, a 17 nm thick Nb light-absorbing thin film 4M1, In a configuration in which a 551 nm thick Nb ₂ O ₅ metal oxide film 4D _{2, a} 13 nm thick Nb light absorbing thin film 4M _{2, and a} 551 nm thick Nb ₂ O ₅ metal oxide film 4D 3 are sequentially stacked, FIG. As shown in comparison with the case where the number of layers of the film 4 is three, the half width of the reflection peak in the three primary color wavelength regions is further reduced. Thus, the half width of the reflection peak in the three primary color wavelength regions decreases as the number of stacked optical multilayer films 4 increases.

In addition, the half width of the reflection peak in the three primary color wavelength regions also varies depending on the refractive index of the metal oxide film 4Di. In FIG. 9, in the selective reflection layer 2 in which the optical multilayer film 4 having a three-layer structure is formed on the Al metal film 3, Nb ₂ O ₅ (refractive index 2.4) is used for the metal oxide films 4D1 and 4D2. The optical characteristics of the case (Al—Nb ₂ O ₅ —Nb—Nb ₂ O ₅ ) and the case of using SiO ₂ (refractive index 1.46) (Al—SiO ₂ —Nb—SiO ₂ ) As the refractive index of the metal oxide film 4Di is smaller, the half width of the reflection peak in the three primary color wavelength regions tends to be smaller. Therefore, the dielectric material of the metal oxide film 4Di is appropriately selected according to the required optical characteristics of the screen. Incidentally, the black level decreases as the half-value width of the reflection peak in the three primary color wavelength regions decreases, but the viewing angle increases as the half-value width of the reflection peak increases.

As described above, the selective reflection layer 2 is composed of the metal film 3 and the optical multilayer film 4, but the metal film 3 reflects the light transmitted through the optical multilayer film 4, and the optical characteristics of the selective reflection layer 2 are as follows. Depends on the optical multilayer film 4. 10 to 12 show only the optical characteristics of the optical multilayer film 4 without the metal film 3 (indicated by a solid curve in the figure) and the optical characteristics when the Al metal film 3 is present (indicated by a broken line in the figure). FIG. Here, the optical multilayer film 4 has a three-layer structure in which Nb ₂ O ₅ is used for the metal oxide films 4D1 and 4D2, and the light absorption thin film 4M1 between the metal oxide films 4D1 and 4D2 is a 19 nm thick Nb film. (FIG. 10), a 17 nm thick Ti film (FIG. 11), and a 15 nm thick Cr film (FIG. 12). Thus, the selective reflection layer 2 having the optical characteristics of the present invention is obtained by forming the optical multilayer film 4 having a very low reflectance in the wavelength region other than the three primary color wavelength regions on the metal film 3. For comparison, FIG. 13 shows optical characteristics when only the light-absorbing thin film 4M1 is an Al film having a thickness of 15 nm. When Al is used for the light-absorbing thin film, the lower limit of the reflectance increases, and it can be seen that the optical characteristics as the selective reflection layer 2 of the present invention cannot be obtained even if formed on the metal film 3.

Further, the optical multilayer film 4 is not limited to the one in which the metal oxide films 4Di and the light absorption thin films 4Mj are alternately stacked. For example, on an Al (50 nm thickness) metal film 3, an optical multilayer film 4, an Nb ₂ O ₅ (534 nm thickness) metal oxide film 4 D 1, an Nb (19 nm thickness) light absorption thin film 4 M 1, In addition, a metal oxide film 4D2 of Nb ₂ O ₅ (538 nm thick), a metal oxide film 4D3 of SiO ₂ (988 nm thick), and a metal oxide film 4D4 of Nb ₂ O ₅ (518 nm thick) are sequentially stacked. Then, it has an optical characteristic as shown in FIG. The design of the optical multilayer film 4 has a higher reflectance peak in the three primary color wavelength regions than the design shown in FIG. 7, thereby further increasing the white level of the screen. This is effective when the light source power of the projector is low.

Still another design example of the optical multilayer film 4 is one in which the reflection intensity in the RGB wavelength region of the selective reflection layer 2 is changed corresponding to the case where the light source of the projector has different intensities in the RGB wavelength regions. Can be mentioned. For example, on the metal film 3 of Al (thickness: 50 nm), the optical multilayer film 4 is composed of a metal oxide film 4D1 of SiO ₂ (thickness of 554 nm), a metal oxide film 4D2 of Nb ₂ O ₅ (thickness of 327 nm), Nb ( The structure in which the light absorption thin films 4M1 having a thickness of 6 nm are sequentially laminated have optical characteristics as shown in FIG. This is a lower reflectance in the wavelength region of green light (G) than in blue light (B) and red light (R).

Further, for example, on the Al (50 nm thickness) metal film 3, as the optical multilayer film 4, SiO ₂ (429 nm thickness) metal oxide film 4D1, Al ₂ O ₃ (392 nm thickness) metal oxide film 4D2, The structure in which the metal oxide film 4D3 of Nb ₂ O ₅ (254 nm thickness) and the light absorption thin film 4M1 of Nb (6 nm thickness) are sequentially laminated has optical characteristics as shown in FIG. This is one in which the reflectance in the wavelength region of red light (R) is lower than that of blue light (B) and green light (G).

  Thus, by the film configuration and film thickness design of the selective reflection layer 2, it is possible to include the three primary color wavelength regions in the specific reflection region and adjust the reflection intensity of each. The configuration of the selective reflection layer 2 is suitable for a light source having sharp emission line peaks in the three primary color wavelength regions, such as a laser projector or a light emitting diode (LED) projector using GLV.

  By the way, in the case of a xenon light source such as SXRD or a high pressure mercury lamp (UHP) light source such as a liquid crystal projector, the light source has a spectrum in the entire visible light region. Even if reflection peaks are arranged in the three primary color wavelength regions, the effect of improving the contrast is not so much seen. Therefore, in this case, it is preferable to design the selective reflection layer 2 so as to selectively absorb bright light peaks of external light, particularly fluorescent lamp light.

  That is, the selective reflection layer 2 composed of the metal film 3 and the optical multilayer film 4 including at least the metal oxide film 4D1 and the light-absorbing thin film 4M1 having transparency as shown in FIG. Is designed in accordance with the wavelength spectrum of external light so as to mainly absorb light and reflect light in other wavelength regions.

  In addition, the selective reflection layer 2 has a high absorption characteristic of, for example, an absorption rate of 70% or more with respect to an emission line spectrum of external light such as a fluorescent lamp, and also for light in a wavelength region other than this wavelength region. For example, the optical multilayer film may be designed so as to have high reflection characteristics such as a reflectance of 70% or more. Specifically, the wavelength region showing the absorption characteristics of the selective reflection layer 2 is designed to include the wavelength of the bright line peak of external light such as a fluorescent lamp.

For example, in a configuration in which a metal oxide film 4D1 made of Nb ₂ O ₅ and a light absorption thin film 4M1 made of Nb are sequentially laminated on the metal film 3 made of Al as the optical multilayer film 4, the structure shown in FIG. The selective reflection layer 2 having optical characteristics as shown in FIG. This has a high absorption rate of, for example, 80% or more in the region of the emission line spectrum of a fluorescent lamp, and has a high reflectance of, for example, 80% or more for light in a wavelength region other than this wavelength region light. The thickness of the Al film (metal film 3) is 50 nm, the thickness of the Nb ₂ O ₅ film (metal oxide film 4D1) is 975 nm, and the thickness of the Nb film (light absorption thin film 4M1) is designed. 12 nm. Here, the case where the emission line peak wavelengths of the fluorescent lamp are 544 nm and 612 nm (FIG. 17A) is taken as an example. Further, for example, even when SiO 2 is added to a thickness of about 50 nm as a barrier film of the Nb film, there is almost no influence on the optical characteristics.

  Alternatively, in the case where the external light is light of a halogen lamp, the wavelength region having an absorption characteristic is set between the wavelength of the bright line peak of the red component and the wavelength of the green line of the planned light source, and the wavelength of the green component. It is preferable to design the selective reflection layer 2 so as to be disposed between the wavelength of the emission line peak and the wavelength of the emission line peak of the blue component.

An example is shown in FIG. Here, the selective reflection layer 2 is formed on an Al (100 nm thickness) metal film 3 as an optical multilayer film 4, and an Nb ₂ O ₅ (450 nm thickness) metal oxide film 4 D 1 and Nb (3 nm thickness) light absorption. The thin film 4M1 and the metal oxide film 4D2 of Nb ₂ O ₅ (330 nm thick) are sequentially stacked, so that the emission line peak of the wavelength 440 nm and the emission line peak of 550 nm are included in the emission line spectrum of the UHP lamp as the light source. And between the emission line peak at 550 nm and the emission line peak at 610 nm, more specifically between 570 nm and 600 nm, and between 500 nm and 530 nm, a wavelength region having absorption characteristics of the selective reflection layer 2 (absorption) Peak) is coming.

  The selective reflection layer 2 having such a configuration has a high reflection characteristic with respect to projector light and a high absorption characteristic with respect to external light such as a fluorescent lamp. The black level is kept low while the level remains high.

Table 3 shows the contrast improvement effect of the present invention. Here, the selective reflection layer (Al film (metal film 3) thickness is 50 nm / Nb ₂ O ₅ film (metal oxide film 4D1) thickness is 975 nm / Nb film (light absorption thin film 4M1) thickness as the reflection layer. 12 nm) and the reflection luminance of each of a xenon lamp and a fluorescent lamp as a projector light source are measured using an Al film. The contrast is obtained by dividing the sum of the reflection luminance of the projector light source and the reflection luminance of the fluorescent lamp by the reflection luminance of the fluorescent lamp. The contrast of the selective reflection layer of the present invention is improved as compared with the case of the Al film that reflects the light of the projector light source and the fluorescent lamp at the same rate, and the selective reflection layer of the present invention absorbs the light of the fluorescent lamp. It can be seen that the ratio is higher than the ratio of absorbing light from the projector light source.

  Regarding the improvement of contrast, the surface of the substrate 1 on which the selective reflection layer 2 is formed has as little surface roughness as possible without causing problems in adhesion to the selective reflection layer 2 and film runnability during film formation. A flat surface is preferred.

Table 4 shows the influence of the surface roughness of the substrate 1 on the contrast. Here, a commercially available PEN film (thickness 100 μm) is used as the substrate 1, and the selective reflection layer (Al film (metal film 3) thickness is 50 nm / Nb ₂ O ₅ film (metal oxide film 4 D 1) thickness on the substrate 1. Sample A having a 975 nm / Nb film (light absorption thin film 4M1) having a thickness of 12 nm) and a substrate 1 on which a binder layer in which fine particles are dispersed is formed on the surface of the PEN film. The results of measuring the reflection luminance of each of the xenon lamp and the fluorescent lamp as the projector light source using the sample B on which the selective reflection layer having the same configuration as in FIG. Here, the substrate for sample A (commercially available PEN film), the substrate for sample B (even if a binder layer in which fine particles are dispersed on the surface of the PEN film), and samples A and B before forming the selective reflection layer are prepared. When the surface roughness was measured using a scanning probe microscope (SPM, Nanoscope 4 manufactured by Digital Instruments) for a 10 μm square region on the surface, the sample A substrate had a centerline average roughness ( Ra) 1.4 nm, maximum height (Rmax) 45 nm, the substrate for sample B was Ra 6.3 nm, Rmax 198 nm, sample A was Ra 4.2 nm, Rmax 44 nm, and sample B was Ra 12.1 nm, Rmax 233 nm. In both samples A and B, there was no problem with the adhesion between the selective reflection layer 2 and the substrate 1.

  As shown in Table 4, in the sample A having a small substrate surface roughness, the reflected light of the projector light is suppressed from being diffused and its reflected luminance is increased compared to the sample B, and the reflected light of the fluorescent lamp light is suppressed from being diffused. As a result, the black level is lowered, and the contrast is improved as compared with the sample B.

As another configuration example of the selective reflection layer 2 that selectively absorbs the emission line peak of the fluorescent lamp light, the constituent material of the metal oxide film 4D1 in the film configuration of the optical multilayer film 4 is Nb ₂ O. Instead of ₅ , a transparent resin formed by a wet process may be used. The optical characteristics are shown in FIG. Also in this case, in the region of the emission line spectrum of the fluorescent lamp, it has a high absorptance of, for example, 80% or more, and for light in a wavelength region other than this wavelength region, it has a high reflectance of, for example, 80% or more. A designed resin film (metal oxide film 4D1) having an Al film (metal film 3) thickness of 50 nm and coated by thermosetting resin JSR Opster (JN7102, refractive index 1.68) Is 1372 nm, and the thickness of the Nb film (light absorption thin film 4M1) is 12 nm.

Further, Table 5 shows the contrast improvement effect according to the present invention when the external light is a halogen lamp light. Here, the selective reflection layer (Al film (metal film 3) thickness is 100 nm / Nb ₂ O ₅ film (metal oxide film 4D1) thickness is 450 nm / Nb film (light absorption thin film 4M1) thickness as the reflection layer. 3 nm) / Nb ₂ O ₅ film (metal oxide film 4D2) having a thickness of 330 nm) and an Al film, the reflection luminance of each of a UHP lamp and a halogen lamp as a projector light source is measured. The contrast of the selective reflection layer of the present invention is improved as compared with the case of the Al film that reflects the light of each of the projector light source and the halogen lamp at the same rate, and the selective reflection layer of the present invention absorbs the light of the halogen lamp. It can be seen that the ratio is higher than the ratio of absorbing light from the projector light source.

  The diffusion layer 5 formed on the selective reflection layer 2 is, for example, a diffusion plate on which a microlens array (MLA) is formed, and has flexibility. In the diffusing layer 5, light in the three primary color wavelength regions reflected by the selective reflection layer 2 is scattered. As a result, the viewing angle is increased and good viewing characteristics can be obtained. Further, the diffusion layer 5 may be formed by arranging a plurality of spherical beads having a diameter of, for example, about several μm to several mm at equal intervals. These beads are made of a transparent material such as glass or a polymer material. Further, the diffusion layer 5 may be one in which metal fine particles such as silver (Ag) and copper (Cu) are dispersed in a predetermined medium. Further, the diffusion layer 5 may be a diffusion plate in which fine uneven shapes are randomly formed on the surface.

  The diffusion layer 5 is provided with a light diffusing surface having characteristics (anisotropy) in which the emitted light falls within a target range, that is, the diffusion angle is different in the vertical direction and the horizontal direction. Preferably there is. Desirably, the vertical diffusion angle is about 20 degrees as the luminance half width, and the horizontal diffusion angle is about 40 degrees as the luminance half width. Thereby, since the light emitted from the screen is controlled so as to be directed within the target visual field, the screen can be made highly visible. In addition, by keeping the vertical diffusion angle within the range where there is no sense of incongruity, the influence of external light having a different incident angle on the diffusion layer 5 from the projection light from the projector device can be reduced and displayed. The contrast of the video can be improved.

Furthermore, when the diffusion layer 5 measures the angular dependence of the diffused light luminance from the diffusion surface of the light irradiated to the diffusion surface at an incident angle of 0 ° in one or both of the vertical direction and the horizontal direction, It is good to have an axis deviation of maximum brightness. Alternatively, in either one or both of the vertical direction and the horizontal direction, the maximum luminance axis is diffused when the angle dependency of the diffused light luminance from the diffusion surface of the light irradiated to the diffusion surface at an incident angle of 0 ° is measured. It is preferred that the layer 5 is inclined with respect to the normal direction of the principal surface, and the luminance distribution is asymmetric with respect to the maximum luminance axis.
As a result, the light emitted from any part of the screen is controlled so as to be directed into the target field of view, so that a high and uniform brightness and gain can be obtained, and a screen with better visibility is provided. Can do.

  These characteristics are achieved by having a fine surface element having a convex or concave shape asymmetric with respect to the normal line of the main surface of the diffusion layer 5 as the light diffusion surface. Specifically, the light diffusing surface can be obtained by transferring the concavo-convex shape of the mold surface formed by sandblasting so that the spraying angle of the abrasive to the mold is less than 90 °.

The screen of the present embodiment can be manufactured as follows. Here, a case where the number of stacked optical multilayer films 4 is two will be described as an example. For example, a selective reflection layer 2 is formed by sequentially laminating a metal film 3, a metal oxide film 4D1, and a light-absorbing thin film 4M1 having transparency on a substrate 1 made of plastic having a thickness of 100 μm, for example. . At this time, the thickness of the metal film 3 is set to 50 nm or more, and the optical multilayer film 4 is formed on the metal film 3 so that it has high reflection characteristics with respect to light in the three primary color wavelength regions of red light, green light, and blue light. And is designed to have a high absorption characteristic for light in a wavelength region other than the three primary color wavelength regions. Finally, a flexible screen is obtained by bonding a diffusion plate to be the diffusion layer 5 on the optical multilayer film 4, for example.
The metal oxide film 4D1 may be formed by a wet process in which a resin solution is applied and cured to form a film.

  A screen provided with a selective reflection layer having such optical characteristics is used as a screen of a front type projector apparatus. Examples of the projector device include laser projectors and LED projectors using GLV, but are not limited to projectors having such laser oscillators and light emitting diodes (LEDs) that emit light of three primary colors as a light source, but also metal halide lamps, high pressure A projector having a light source such as a mercury lamp or a xenon lamp is also used.

  As described above, in the present embodiment, an optical multilayer film made up of a metal oxide film and a light-absorbing thin film having transparency is formed on the metal film, so that, for example, it is highly reflective to light in the three primary color wavelength regions. It is possible to obtain a screen having characteristics and having high absorption characteristics for light in other wavelength regions, and realizing a screen with high white level and low black level, and thus high brightness and high contrast. Can do.

  In addition, an optical multilayer film consisting of a metal oxide film and a light-absorbing thin film having transparency is less dependent on the film thickness than an optical multilayer film in which a high refractive index layer and a low refractive index layer are alternately laminated, and is incident. Since the angle dependency is small, a wide viewing angle can be obtained, the screen can be enlarged, the manufacturing margin can be increased, and the productivity can be improved.

  Also, depending on the refractive index and the number of layers of the metal oxide film in the optical multilayer film, for example, the half-value width of the reflection peak in the three primary color wavelength regions can be reduced or increased, and can be arbitrarily adjusted. In addition, it is possible to obtain a screen with excellent image quality in consideration of contrast and viewing angle.

  In addition, the design of the optical multilayer film allows the reflectance for light in the three primary color wavelength regions to be raised, lowered, or arbitrarily adjusted, and a high-contrast screen that matches the light source power of the projector can be realized. .

  In addition, by designing the optical multilayer film, it is possible to adjust the reflectance in each wavelength region of RGB, and to realize a screen capable of adjusting the color of an image according to the light source intensity of the projector in each RGB wavelength region. Can do.

  In addition, the optical multilayer film can be designed to adjust the wavelength region exhibiting absorption characteristics, and the wavelength of the bright line peak of external light can be included in the wavelength region exhibiting absorption characteristics, thereby realizing a high-contrast screen. .

  Further, in the present embodiment, a substrate made of any material can be used in accordance with the usage pattern. When a flexible substrate is used, the metal film of the selective reflection layer and the film of the optical multilayer film are used. Since the thickness is thin, a flexible screen can be obtained.

  In this embodiment, the diffusion layer 5 is formed on the selective reflection layer 2 as shown in FIG. 1, but as a modified example of this embodiment, as shown in FIG. A plurality of convex portions 6 (or concave portions) may be provided on the surface, and the selective reflection layer 2 having a shape in accordance with the surface shape of the substrate 1 may be formed thereon. In this configuration, since the scattering of light can be controlled by the shape of the convex portion 6 (or the concave portion), the diffusion layer 5 becomes unnecessary, the thickness of the screen can be further reduced, and the cost can be reduced. be able to.

Next, a second embodiment of the screen of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part which is common in 1st Embodiment, and the overlapping description is abbreviate | omitted.
21, in the screen of the present embodiment, an optical multilayer film 4 including at least a metal oxide film 4D1 and a light-absorbing thin film 4M1 having transparency is formed on a metal substrate 11, and the optical multilayer film 4 is formed on the screen. A diffusion layer 5 is formed. Compared to the first embodiment shown in FIG. 1, the metal film 3 is omitted.

  In this configuration, the metal substrate 11 is made of the same material as that of the metal film 3. The optical multilayer film 4 composed of the metal oxide film 4Di (i = 1, 2,...) And the light absorption thin film 4Mj (j = 1, 2,...) Is directly formed on the metal substrate 11 as described above. Thus, the selective reflection layer 2 having the same optical characteristics as in the first embodiment can be obtained. Also in this case, the design of the optical multilayer film 4 is performed in the same manner as in the first embodiment.

  The screen can be manufactured as follows. Taking the case where the optical multilayer film 4 has a two-layer structure as an example, a metal oxide film 4D1 and a light absorption thin film 4M1 are sequentially laminated on a metal substrate 11 having a thickness of several tens of μm, for example, using a sputtering method, for example. The metal oxide film 4D1 and the light-absorbing thin film 4M1 are formed on the metal substrate 11, so that they have high reflection characteristics with respect to light of the three primary color wavelength regions of red light, green light, and blue light, and the three primary color wavelength regions. It is designed to have a high absorption characteristic for light in a wavelength region other than. Finally, a diffusion layer 5 is formed on the optical multilayer film 4 by bonding, for example, a diffusion plate to complete the screen.

  Also in the second embodiment, it is possible to obtain a screen having the same optical characteristics as in the first embodiment, and thus to realize a high-brightness and high-contrast screen capable of obtaining a clear image under bright light. Can do. In the present embodiment, since a metal substrate is used, the formation of the metal film can be omitted, the screen configuration becomes simpler, and the manufacture becomes easier.

  As a modification of the present embodiment, instead of forming the diffusion layer 5, a large number of convex portions (or concave portions) are provided on the surface of the metal substrate 11, and the optical multilayer film 4 is formed in the same shape thereon. It is good also as a structure to form.

Next, a third embodiment of the screen of the present invention will be described with reference to FIG. Portions common to the first and second embodiments are denoted by the same reference numerals, and redundant description is omitted.
In FIG. 22, the screen of the present embodiment includes a selective reflection layer 2 composed of a metal film 3 and an optical multilayer film 4, and a diffusion layer 5.

  The screen having this configuration has, for example, two optical multilayer films 4 in the reverse order to the order formed on the substrate 1 in the first embodiment by sputtering, for example, on the back surface of the diffusion plate to be the diffusion layer 5. In the case of the layer structure, the light absorption thin film 4M1 and then the metal oxide film 4D1 are formed first, and then the metal film 3 is finally formed. The optical multilayer film 4 composed of the metal oxide film 4Di (i = 1, 2,...) And the light absorbing thin film 4Mj (j = 1, 2,...) Is designed in the same manner as in the first embodiment.

  In the present embodiment, a screen having the same performance as that of the first embodiment can be created without a substrate, and a flexible screen can be easily obtained and the manufacturing cost can be reduced. Can do.

Next, a fourth embodiment of the screen of the present invention will be described with reference to FIG.
The screen of the present invention is obtained by adhering the selective reflection layer 2 and the diffusion layer 5 through the pressure-sensitive adhesive layer 6 having a predetermined light absorption characteristic in the screen shown in FIG. The configuration is the same as in FIG.

  The pressure-sensitive adhesive layer 6 is a film having an adhesive property for bonding the selective reflection layer 2 and the diffusion layer 5 and having a light absorption characteristic. This light absorption characteristic is displayed on the color coordinates of the projector light source and the screen. It is set to match the color coordinates of the video to be recorded. Therefore, in the pressure-sensitive adhesive layer 6, a dye that absorbs light in a specific wavelength region and a black dye that is carbon black are added and dispersed.

  The pigment that absorbs light in the specific wavelength region may be any material of pigment pigment and dye pigment, and both are preferably magenta materials that absorb green light.

  Here, as the above-mentioned dye, for example, a dye having a high absorption rate in the vicinity of 532 nm, specifically 525 to 560 nm, for example, a compound such as cyanine, squalium, azomethine, xanthene, oxonol, or azo, preferably cyanine More preferred examples include cyanine compounds represented by the following structural formula (A). These dyes are dyes having a maximum absorption wavelength at 550 to 620 nm, that is, dyes having a maximum absorption wavelength in an orange light region including neon light. In the present invention, the absorption characteristics in the wavelength region of green light are used. To do.

In addition, pigment red (PR) dyes are preferable as pigment dyes, and examples thereof include dichloroquinacridone (PR209) represented by the following structural formula. This dye has a minimum transmittance of 540 nm in the wavelength range of 525 to 560 nm (minimum transmission wavelength), and the transmittance is smaller than the minimum transmittance values in the blue and red wavelength regions.
Examples of the dye having similar characteristics include diketopyrrolopyrrole (PR254) having a minimum transmission wavelength of 544 nm and dimethylquinacridone (PR122) having a wavelength of 510 nm.

  Moreover, as what can be added to the pressure-sensitive adhesive layer 2, metal fine particles and metal-coated fine particles may be used as long as they absorb green light. For example, gold colloid having a minimum transmission wavelength of 529 nm is available.

  The pressure-sensitive adhesive layer 6 may be designed with the dye addition amount, film thickness, etc. in consideration of the transmittance in the target wavelength region.

  In FIG. 24, the example of the light transmission characteristic of the adhesive layer 6 is shown. In this example, the light transmittance in the red wavelength region is the highest, the light transmittance in the blue wavelength region is high, and the light transmittance in the green wavelength region is the lowest. That is, the amount of light absorption in each of the three primary color wavelength regions is different, and is shown as the length of the arrow in FIG. Here, it was about 25% at the blue wavelength, about 30% at the green wavelength, and about 18% at the red wavelength.

  Further, as the light absorption / transmission characteristics of the pressure-sensitive adhesive layer 6, light in the green wavelength range (500 to 600 nm wavelength range), which is one of a plurality of specific wavelength ranges exhibiting high reflection characteristics in the selective reflection layer 2 Of light). In addition, the transmittance in the red wavelength region, which is one of the light in the plurality of specific wavelength regions exhibiting high reflection characteristics in the selective reflection layer 2, is higher than the transmittance in the blue and green wavelength regions. Thereby, for example, the imbalance between the excessive spectral intensity in the green wavelength region and the insufficient spectral intensity in the red wavelength region in a light source such as a UHP lamp can be compensated by the light absorption of the adhesive layer 6. An image with good white balance can be displayed.

  That is, a part of the light incident on the screen is absorbed according to the light absorption characteristics shown in FIG. 24 when passing through the pressure-sensitive adhesive layer 6, and then reaches the selective reflection layer 2. The selective reflection layer 2 absorbs the external light component included in the incident light, and selectively reflects only light in a specific wavelength region related to the image (usually light in the RGB primary color wavelength region). Then, when the reflected light passes through the adhesive layer 6, light in a specific wavelength region (green light in the case of a UHP lamp) is particularly absorbed, and light in the red wavelength region is transmitted with high transmittance. Therefore, the emission intensity is balanced and diffused on the surface of the diffusion layer 5 and provided to the viewer as video light having a wide viewing angle. Further, as shown in FIG. 25, since the optical path length of external light in the pressure-sensitive adhesive layer 6 has a certain incident angle, it is absorbed more because it is longer than the optical path length of light from the projector. Therefore, it is possible to eliminate the influence of external light on the image light that is the reflected light at a high level, and it is possible to provide an image with excellent contrast and high color reproducibility.

  In the present embodiment, an example in which the light absorption characteristic for matching the color coordinate of the projector light source and the color coordinate of the image displayed on the screen is given to the adhesive layer 6 has been shown. It may be applied to the diffusion layer 5. In this case, it is preferable to add and disperse a dye that absorbs light in a specific wavelength region and a black dye that is carbon black in the resin constituting the diffusion layer 5.

It is sectional drawing which shows 1st Embodiment of the screen of this invention. Is a diagram showing the reflection characteristics of the _{Al / Nb 2 O 5 (539nm} ) / Nb (6nm) consisting selective reflective layer. A selective reflection layer composed of Al / Nb ₂ O ₅ (450 nm) / Nb (3 nm) / Nb ₂ O ₅ (450 nm) and Al / Nb ₂ O ₅ (450 nm) / Nb (3 nm) / Nb ₂ O ₅ (330 nm) It is a figure which shows the reflective characteristic of the selective reflection layer which consists of. Is a graph showing the reflection property of the film made of Al / _Nb 2 _{O 5.} It is a figure which shows the film thickness dependence of the reflectance in the three primary color wavelength range of a selective reflection layer. It is a figure which shows the incident angle dependence of the reflectance in the three primary color wavelength range of a selective reflection layer. Is a diagram showing the reflection characteristics of the _{Al / Nb 2 O 5 (534nm} ) / Nb (19nm) / Nb 2 O 5 made of (534 nm) selective reflective layer. Is a diagram showing the reflection characteristics of the _{Al / Nb 2 O 5 (551nm} ) / Nb (17nm) / Nb 2 O 5 (551nm) / Nb (13nm) / Nb 2 O 5 (551nm) consisting of the selective reflection layer. It is a diagram illustrating in comparison the reflection characteristics of the _{Al-Nb 2 O 5 -Nb-} Nb 2 O 5 consisting selective reflection layer and the Al-SiO ₂ consisting -Nb-SiO ₂ selective reflective layer. Diagram showing the reflection characteristics of the _{Nb 2 O 5 -Nb (19nm)} -Nb 2 O 5 reflection characteristics of the optical multilayer film composed of the _{Al-Nb 2 O 5 -Nb (} 19nm) -Nb 2 O consisting of ₅ selective reflection layer It is. Diagram showing the reflection characteristics of the _{Nb 2 O 5 -Ti (17nm)} -Nb 2 O 5 reflection characteristics of the optical multilayer film composed of the _{Al-Nb 2 O 5 -Ti (} 17nm) -Nb 2 O consisting of ₅ selective reflection layer It is. Diagram showing the reflection characteristics of the _{Nb 2 O 5 -Cr (15nm)} -Nb 2 O reflection characteristic of the optical multilayer film composed of ₅ and _{Al-Nb 2 O 5 -Cr (} 15nm) -Nb consisting 2 _{O 5} selective reflective layer It is. Is a diagram showing a _{Nb 2 O 5 -Al (15nm)} -Nb 2 O 5 system of the reflection characteristic and the _{Al-Nb 2 O 5 -Al (} 15nm) -Nb 2 O 5 based reflective properties of. Is a diagram showing the reflection characteristics of the _{Al / Nb 2 O 5 (534nm} ) / Nb (19nm) / Nb 2 O 5 (538nm) / SiO 2 (988nm) / Nb 2 O 5 (518nm) consisting of the selective reflection layer. It is a diagram showing the reflection characteristics of the _{Al / SiO 2 (554nm) /} Nb 2 O 5 (327nm) / Nb (6nm) consisting selective reflective layer. Is a diagram showing the reflection characteristics of the _{Al / SiO 2 (429nm) /} Al 2 O 3 (392nm) / Nb 2 O 5 (254nm) / Nb (6nm) consisting selective reflective layer. It is a graph showing the reflection property of the selective reflective layer of bright line spectra and Al / _Nb 2 _{O 5} of the fluorescent lamp (975nm) / Nb (12nm) . Is a diagram illustrating a bright line spectrum of the reflection characteristic and a light source of _{Al (100nm) / Nb 2 O} 5 (450nm) / Nb (3nm) / Nb 2 O 5 selective reflective layer of (330 nm). It is a figure which shows the reflective characteristic of the selective reflection layer which consists of Al / resin film | membrane (refractive index 1.68, 1372 nm) / Nb (12 nm). It is sectional drawing which shows the modification of 1st Embodiment. It is sectional drawing which shows 2nd Embodiment of the screen of this invention. It is sectional drawing which shows 3rd Embodiment of the screen of this invention. It is sectional drawing which shows 4th Embodiment of the screen of this invention. It is a figure which shows the light transmission characteristic of the adhesive layer of the screen of this invention. It is a figure which shows the incident state of the projector light and external light to the adhesive layer of the screen of this invention. It is sectional drawing which shows the screen of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Selective reflection layer, 3 ... Metal film, 4 ... Optical multilayer film, 4D ... Metal oxide film, 4M ... Light-absorbing thin film having transparency, 5 ... Diffusion layer, 6 …… Adhesive layer, 11 …… Metal substrate

Claims (9)

In a screen that displays an image by projected light,
An optical multilayer film comprising a plurality of metal oxide films and a light-absorbing thin film having transparency, and a reflective layer that reflects the light transmitted through the optical multilayer film, and for light in a specific wavelength region corresponding to the projection light A selective reflection layer having a reflection characteristic, and having an absorption characteristic for light in a wavelength region excluding the specific wavelength region,
A diffusion layer for scattering the reflected light of the selective reflection layer;
An adhesive layer that bonds the selective reflection layer and the diffusion layer together,
In the metal oxide film immediately above the reflective layer, the wavelength region of the absorption characteristic is between the wavelength of the emission line peak of the red component and the wavelength of the emission line peak of the green component, and the wavelength of the emission line peak of the green component. The refractive index and / or the film thickness is adjusted to be between the wavelength of the emission line peak of the blue component,
The pressure-sensitive adhesive layer absorbs light in the green wavelength region,
The pressure-sensitive adhesive layer has the highest light transmittance in the red wavelength region, which is one of a plurality of specific wavelength regions exhibiting high reflection characteristics in the selective reflection layer, and has high reflection characteristics in the selective reflection layer. A screen having the lowest light transmittance in a green wavelength region, which is one of a plurality of specific wavelength regions shown .   The screen according to claim 1, wherein the selective reflection layer has a metal oxide film whose refractive index and / or film thickness is adjusted in order to balance the chromaticity of the reflected light.   2. The screen according to claim 1, wherein the light-absorbing thin film is made of a material having a refractive index of 1 or more and an absorption coefficient of 0.5 or more.   The material of the light absorbing thin film is Nb, Nb-based alloy, C, Cr, Fe, Ge, Ni, Pd, Pt, Rh, Ti, TiN, TiNxWy, Mn, Ru, or PbTe. 3. The screen according to 3. The metal oxide film is a dielectric film made of Nb ₂ O ₅ , TiO ₂ , Ta ₂ O ₅ , Al ₂ O ₃ or SiO ₂ , or In ₂ O ₃ , SnO ₂ , ZnO, In ₂ O ₃ —SnO. The screen according to claim 1, which is a conductive film made of a material in which _two compounds or any of these are doped with a metal.   The screen according to claim 1, wherein the reflective layer is made of a metal or alloy of any one of Al, Nb, and Ag. In a screen that displays an image by projected light,
An optical multilayer film comprising a plurality of metal oxide films and a light-absorbing thin film having transparency, and a reflective layer that reflects the light transmitted through the optical multilayer film, and for light in a specific wavelength region corresponding to the projection light A selective reflection layer having a reflection characteristic, and having an absorption characteristic for light in a wavelength region excluding the specific wavelength region,
A diffusion layer for scattering the reflected light of the selective reflection layer,
In the metal oxide film immediately above the reflective layer, the wavelength region of the absorption characteristic is between the wavelength of the emission line peak of the red component and the wavelength of the emission line peak of the green component, and the wavelength of the emission line peak of the green component. The refractive index and / or the film thickness is adjusted to be between the wavelength of the emission line peak of the blue component,
The diffusion layer absorbs light in the green wavelength region,
The diffusion layer has the highest light transmittance in the red wavelength region, which is one of a plurality of specific wavelength regions exhibiting high reflection characteristics in the selective reflection layer, and exhibits high reflection characteristics in the selective reflection layer. A screen having the lowest light transmittance in a green wavelength region which is one of a plurality of specific wavelength regions . An optical multilayer film composed of a plurality of metal oxide films and a light-absorbing thin film having transparency, and a reflective layer that reflects the light transmitted through the optical multilayer film are formed, and has reflection characteristics for light in a specific wavelength region. And a selective reflection layer forming step that forms a selective reflection layer having absorption characteristics with respect to light in a wavelength region other than the specific wavelength region ,
A step of bonding the selective reflection layer and the diffusion layer through an adhesive layer,
In the selective reflection layer forming step, the wavelength region of the absorption characteristic is between the wavelength of the emission line peak of the red component and the wavelength of the emission line peak of the green component, and between the wavelength of the emission line peak of the green component and the wavelength of the blue component. Including the step of setting the refractive index and / or film thickness of the metal oxide film immediately above the reflective layer so as to be between the wavelengths of the emission line peak,
The pressure-sensitive adhesive layer absorbs light in the green wavelength region,
The pressure-sensitive adhesive layer has the highest light transmittance in the red wavelength region, which is one of a plurality of specific wavelength regions exhibiting high reflection characteristics in the selective reflection layer, and has high reflection characteristics in the selective reflection layer. A method for manufacturing a screen, wherein the transmittance of light in a green wavelength region, which is one of a plurality of specific wavelength regions shown, is lowest. An optical multilayer film composed of a plurality of metal oxide films and a light-absorbing thin film having transparency, and a reflective layer that reflects the light transmitted through the optical multilayer film are formed, and has reflection characteristics for light in a specific wavelength region. And a selective reflection layer forming step that forms a selective reflection layer having absorption characteristics with respect to light in a wavelength region other than the specific wavelength region ,
Forming a diffusion layer on the selective reflection layer,
In the selective reflection layer forming step, the wavelength region of the absorption characteristic is between the wavelength of the emission line peak of the red component and the wavelength of the emission line peak of the green component, and between the wavelength of the emission line peak of the green component and the wavelength of the blue component. Including the step of setting the refractive index and / or film thickness of the metal oxide film immediately above the reflective layer so as to be between the wavelengths of the emission line peak,
The diffusion layer absorbs light in the green wavelength region,
The diffusion layer has the highest light transmittance in the red wavelength region, which is one of a plurality of specific wavelength regions exhibiting high reflection characteristics in the selective reflection layer, and exhibits high reflection characteristics in the selective reflection layer. A method for manufacturing a screen, wherein the transmittance of light in a green wavelength region, which is one of a plurality of specific wavelength regions, is lowest.

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