Screens and projection systems for projection devices

Abstract

To provide a projection screen and projection system that minimizes variations in contrast and color due to viewing angle. [Solution] The projection screen of the present invention emits projection light comprising a first light in a first wavelength band and a second light in a second wavelength band different from the first wavelength band, and comprises a wavelength-selective layer having a light-transmitting base material and a plurality of colloidal amorphous materials dispersed in the base material. The plurality of colloidal amorphous materials include a first colloidal amorphous material exhibiting a first structural color corresponding to the first wavelength band and a second colloidal amorphous material exhibiting a second structural color corresponding to the second wavelength band.

Description

Technical Field

[0001] The present invention relates to a screen for a projection device and a projection system.

Background Art

[0002] A reflective screen that reflects projection light emitted from a projection device and displays an image on the observation side has been conventionally known. As this type of reflective screen, a technique is known in which external light noise is removed by selectively reflecting only light of a specific wavelength corresponding to the projection light emitted from a projector, thereby enhancing the contrast of the projection image. Patent Document 1 below discloses a screen in which a red reflective particle layer, a green reflective particle layer, and a blue reflective particle layer in which a plurality of fine particles are regularly arranged are laminated on a substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the screen of Patent Document 1, each particle layer has a structure in which the refractive index periodically changes on the order of the wavelength of light due to the regular arrangement of a plurality of particles. A material having this type of structure exhibits the property of reflecting light of a specific wavelength by Bragg reflection. As a result, the light of a specific wavelength reflected by each particle layer is observed as a structural color. However, there is a problem that the viewing angle of the structural color exhibited by Bragg reflection is narrow, and variations in contrast and color tone are likely to occur depending on the viewing angle.

Means for Solving the Problems

[0005] To solve the above problems, a projection screen according to one aspect of the present invention is a projection screen for a projection device that emits projection light including first light in a first wavelength band and second light in a second wavelength band different from the first wavelength band, and comprises a wavelength-selective layer having a light-transmitting base material and a plurality of colloidal amorphous materials dispersed in the base material. The plurality of colloidal amorphous materials include a first colloidal amorphous material exhibiting a first structural color corresponding to the first wavelength band and a second colloidal amorphous material exhibiting a second structural color corresponding to the second wavelength band.

[0006] A projection system according to one aspect of the present invention comprises a screen for a projection device according to one aspect of the present invention, and a projection device that emits the projection light toward the screen for the projection device. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram of the projection system according to the first embodiment. [Figure 2] This is a cross-sectional view of the screen along the line II-II in Figure 1. [Figure 3] This is a schematic diagram showing a part of colloidal amorphous material. [Figure 4] This figure shows the principle of Bragg reflection in colloidal crystals. [Figure 5] This is a cross-sectional view of the screen according to the second embodiment. [Figure 6] This is a cross-sectional view of the screen according to the third embodiment. [Figure 7] This is a cross-sectional view of the screen according to the fourth embodiment. [Figure 8] This is a cross-sectional view of the screen according to the fifth embodiment. [Figure 9] This is a cross-sectional view of the screen according to the sixth embodiment. [Modes for carrying out the invention]

[0008] [First Embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In the following drawings, the dimensions of each component may be shown on a different scale to make them easier to see.

[0009] Figure 1 is a schematic diagram of the projection system 10 of this embodiment. As shown in Figure 1, the projection system 10 of this embodiment comprises a projection screen 11 and a projection device 12. Hereinafter, the projection screen 11 will simply be referred to as screen 11. The projection device 12 emits projection light L toward the screen 11. The screen 11 reflects the projection light L emitted from the projection device 12 and displays an image on the observer's side. In the following description, the axis along the horizontal direction of the screen 11 will be referred to as the X-axis, the axis along the vertical direction of the screen 11 will be referred to as the Y-axis, and the axis along the front direction of the screen 11 will be referred to as the Z-axis. That is, as viewed from the observer, the left-right direction corresponds to the X-axis direction, the up-down direction corresponds to the Y-axis direction, and the depth direction corresponds to the Z-axis direction.

[0010] Figure 2 is a cross-sectional view of screen 11 along the line II-II in Figure 1. As shown in Figure 2, the screen 11 comprises a wavelength-selective layer 17 having a light-transmitting base material 14 and a plurality of colloidal amorphous materials 15 dispersed in the base material 14. In this embodiment, the wavelength-selective layer 17 is a light-transmitting film-like member. The thickness of the wavelength-selective layer 17 is, for example, about 50 μm to 20 mm. In this specification, of the two surfaces of the wavelength-selective layer 17, the surface on the observation side is referred to as the first surface 17a, and the surface opposite to the observation side is referred to as the second surface 17b.

[0011] The multiple colloidal amorphous materials 15 include multiple first colloidal amorphous materials 15B, multiple second colloidal amorphous materials 15G, and multiple third colloidal amorphous materials 15R. The multiple first colloidal amorphous materials 15B, multiple second colloidal amorphous materials 15G, and multiple third colloidal amorphous materials 15R exist in a substantially uniformly dispersed state within the matrix material 14.

[0012] Now, let's discuss colloidal amorphous material 15. Figure 3 is a schematic diagram showing a portion of colloidal amorphous material 15. Figure 4 is a diagram illustrating the principle of Bragg reflection in colloidal crystals. Generally, particles with a particle size in the nanoscale range are called colloidal particles, and as shown in Figure 4, an aggregate of colloidal particles 20 with uniform particle sizes arranged periodically is called a colloidal crystal. In many cases, colloidal crystals have a period of about the same magnitude as the wavelength of visible light, and selectively reflect light of a specific wavelength in the visible range corresponding to that period.

[0013] In contrast, as shown in Figure 3, a non-crystalline or microcrystalline aggregate in which multiple particles 19 are regularly arranged in all directions within a plane parallel to an arbitrary reference plane, for example, the first surface 17a of the wavelength-selective layer 17 in this embodiment, and the period of the regularly arranged units does not exceed 20 particles, is called colloidal amorphous material 15. Therefore, in colloidal amorphous material 15, the regular arrangement of particles 19 does not have long-range order but has short-range order. Also, the lattice planes of colloidal amorphous material 15 are oriented in all directions. The structure of this type of colloidal amorphous material 15 can be confirmed by observing a plane parallel to the above-mentioned reference plane using a scanning electron microscope.

[0014] In the case of this embodiment, examples of the specific material of the particles 19 constituting the colloidal amorphous 15 include silica particles. The refractive index of the silica particles is about 1.45. In addition, as organic materials, polystyrene particles, polymethyl methacrylate particles, etc. can be used. The refractive index of polystyrene particles is about 1.6. The refractive index of polymethyl methacrylate particles is about 1.49. In addition, polyimide resins, polyacrylic resins, methacrylic acid esters and their derivatives, epoxy resins, polycarbonate resins, polyamide resins, polyurethane resins, etc. may also be used. The particle size of the particles 19 is, for example, about 100 to 500 nm, and it is desirable that the variation in the particle size is ±20 nm or less. The overall shape of the colloidal amorphous 15 formed by aggregation of the plurality of particles 19 is substantially spherical, and the particle size of the colloidal amorphous 15 is, for example, about 10 to 100 μm. The content of the colloidal amorphous 15 in the wavelength selection layer 17 is an amount that occupies an area of 10% or more of the entire area of the wavelength selection layer 17 when viewed from the normal direction.

[0015] The particle sizes of the plurality of particles 19 constituting the first colloidal amorphous 15B are substantially the same. The particle sizes of the plurality of particles 19 constituting the second colloidal amorphous 15G are substantially the same. The particle sizes of the plurality of particles 19 constituting the third colloidal amorphous 15R are substantially the same. The particle size of the particles 19 constituting the first colloidal amorphous 15B, the particle size of the particles 19 constituting the second colloidal amorphous 15G, and the particle size of the particles 19 constituting the third colloidal amorphous 15R are different from each other.

[0016] Specifically, the particle size of the particles 19 constituting the first colloidal amorphous 15B is smaller than the particle size of the particles 19 constituting the second colloidal amorphous 15G. The particle size of the particles 19 constituting the second colloidal amorphous 15G is smaller than the particle size of the particles 19 constituting the third colloidal amorphous 15R. That is, if the particle size of the particles 19 constituting the first colloidal amorphous 15B is d1, the particle size of the particles 19 constituting the second colloidal amorphous 15G is d2, and the particle size of the particles 19 constituting the third colloidal amorphous 15R is d3, then d1 < d2 < d3. Note that the particle size of the first colloidal amorphous 15B, the particle size of the second colloidal amorphous 15B, and the particle size of the third colloidal amorphous 15R may be the same or different.

[0017] As described above, since the particle sizes of the particles 19 constituting the three types of colloidal amorphous 15B, 15G, and 15R are different from each other, the periods of the refractive index changes of the three types of colloidal amorphous 15B, 15G, and 15R are different from each other. As a result, the wavelengths of the light reflected by the three types of colloidal amorphous 15B, 15G, and 15R are different from each other, and the structural colors exhibited by the three types of colloidal amorphous 15B, 15G, and 15R are different from each other.

[0018] Specifically, the first colloidal amorphous 15B exhibits a blue structural color corresponding to the wavelength band of blue light included in the projection light L emitted from the projection device 12. The second colloidal amorphous 15G exhibits a green structural color corresponding to the wavelength band of green light included in the projection light L emitted from the projection device 12. The third colloidal amorphous 15R exhibits a red structural color corresponding to the wavelength band of red light included in the projection light L emitted from the projection device 12. The blue structural color corresponding to the blue wavelength band in the present embodiment corresponds to the first structural color corresponding to the first wavelength band in the claims. The green structural color corresponding to the green wavelength band in the present embodiment corresponds to the second structural color corresponding to the second wavelength band in the claims. The red structural color corresponding to the red wavelength band in the present embodiment corresponds to the third structural color corresponding to the third wavelength band in the claims.

[0019] The base material 14 is composed of a light-transmitting resin material. An example of the resin material is ethoxylated trimethylolpropane triacrylate containing 1% by weight of 2-hydroxy-2-methylpropiophenone or 0.5% by weight of a phosphine oxide compound as a photoinitiator. Alternatively, resin materials such as polymethyl methacrylate can be used. Other materials such as polyester resins, vinyl resins, polycarbonate resins, polystyrene resins, polyethylene terephthalate resins, polyethylene naphthalate resins, polyvinyl butyral resins, polyimide resins, and polystyrene resins may also be used.

[0020] The refractive indices of the colloidal amorphous material 15 and the matrix material 14 are different. It is desirable that the difference between the refractive indices of the colloidal amorphous material 15 and the matrix material 14 be relatively small, for example, 0.01 or greater and 0.1 or less. By reducing the difference between the refractive indices of the colloidal amorphous material 15 and the matrix material 14 to approximately the above values, the full width at half maximum (FWHM) of the reflection wavelength spectrum of the colloidal amorphous material 15 can be narrowed, thereby increasing the saturation of the structural color. Considering this effect, it is desirable that the projected light L emitted from the projection device 12 is light with a narrow bandwidth, such as laser light.

[0021] In manufacturing the screen 11 of this embodiment, a liquid base material 14 containing colloidal amorphous material 15 is prepared, and then the liquid is molded into a film using methods such as extrusion molding, solution casting, or various coating methods, and then cured.

[0022] (Effects of the first embodiment) The screen 11 of this embodiment is a screen for a projection device that emits projection light L containing blue light, green light, and red light, and comprises a wavelength-selective layer 17 having a light-transmitting base material 14 and a plurality of colloidal amorphous materials 15 dispersed in the base material 14. The plurality of colloidal amorphous materials 15 include a first colloidal amorphous material 15B that exhibits a blue structural color corresponding to the blue light contained in the projection light L, a second colloidal amorphous material 15G that exhibits a green structural color corresponding to the green light contained in the projection light L, and a third colloidal amorphous material 15R that exhibits a red structural color corresponding to the red light contained in the projection light L.

[0023] As mentioned above, Patent Document 1, Japanese Patent Application Publication No. 2003-330119, discloses a screen using a colloidal crystal that selectively reflects light of a specific wavelength. However, in general colloidal crystals, as shown in Figure 4, multiple particles are arranged regularly with a period of approximately the wavelength of light. This type of colloidal crystal exhibits the property of selectively reflecting light of a specific wavelength through Bragg reflection. If the period of the lattice plane in the colloidal crystal is d, the wavelength of light is λ, the mode refractive index is n, and the angle of apparent emission of light (complementary angle of incidence) is θ, then the Bragg condition described in Patent Document 1 is given by the following equation. λ = 2(d / m)(n 2 -sin 2 θ) 1 / 2 (m: integer) When the Bragg condition is met, reinforcement interference occurs between reflected light rays, resulting in strong reflected light being observed in a specific direction. Conversely, if the Bragg condition is not met, strong reflected light is not observed. Thus, structural colors produced by Bragg reflection have a narrow viewing angle, and there is a problem in that the contrast and hue tend to vary depending on the viewing angle.

[0024] To address this challenge, the screen 11 of this embodiment includes a wavelength-selective layer 17 containing a first colloidal amorphous material 15B, a second colloidal amorphous material 15G, and a third colloidal amorphous material 15R. As shown in Figure 3, each unit of regularly arranged particles 19 has a lattice plane facing a different direction, and when viewed as a whole, the colloidal amorphous material 15 has lattice planes facing in all directions. Therefore, the Bragg condition described above is satisfied for projected light L incident from various directions, and the three types of colloidal amorphous materials 15B, 15G, and 15R can reflect light of a specific wavelength in all directions. Thus, because the viewing angle of the structural color produced by the colloidal amorphous material 15 is wide, a screen 11 can be realized that is less prone to variations in contrast and hue depending on the viewing angle.

[0025] In the screen 11 of this embodiment, the wavelength-selective layer 17 is composed of a single layer of base material 14 in which a first colloidal amorphous material 15B, a second colloidal amorphous material 15G, and a third colloidal amorphous material 15R are dispersed. With this configuration, unlike when the wavelength-selective layer is composed of multiple layers, there is no interface of the base material 14 inside the wavelength-selective layer 17, so light loss is reduced and a screen 11 with high light utilization efficiency can be realized.

[0026] The projection system 10 of this embodiment comprises a screen 11 of this embodiment and a projection device 12 that emits projection light L toward the screen 11. This configuration makes it possible to provide a projection system 10 with superior display quality.

[0027] [Second Embodiment] A second embodiment of the present invention will be described below with reference to Figure 5. Since the basic configuration of the screen in this embodiment is the same as in the first embodiment, a description of the common parts will be omitted. Figure 5 is a cross-sectional view of the screen 21 of the second embodiment. In Figure 5, components common to the drawings used in the first embodiment are denoted by the same reference numerals.

[0028] As shown in Figure 5, the screen 21 of this embodiment comprises a matrix 14, a wavelength-selective layer 23 having a plurality of colloidal amorphous materials 15, and a plurality of light-absorbing particles 22. The plurality of colloidal amorphous materials 15 and the plurality of light-absorbing particles 22 are dispersed inside the matrix 14.

[0029] The light-absorbing particles 22 absorb light in wavelength bands other than the blue, green, and red light bands contained in the projected light L. Specific examples of materials for the light-absorbing particles 22 include carbon, polydopamine, and black-colored polymer particles. The content of the light-absorbing particles 22 is preferably about 0.2 to 2% by weight relative to the base material 14.

[0030] (Effects of the second embodiment) In this embodiment as well, the same effects as in the first embodiment can be obtained, such as the realization of a screen 21 that is less prone to variations in contrast and color depending on the viewing angle, because the wavelength-selective layer 23 has colloidal amorphous material 15.

[0031] Furthermore, in the screen 21 of this embodiment, since the wavelength-selective layer 23 has light-absorbing particles 22, light other than the projected light L emitted from the projection device 12, specifically ambient light that is unnecessary for display, is absorbed by the light-absorbing particles 22. This makes it possible to enhance the contrast of the projected image.

[0032] [Third Embodiment] A third embodiment of the present invention will be described below with reference to Figure 6. Since the basic configuration of the screen in this embodiment is the same as in the first embodiment, a description of the common parts will be omitted. Figure 6 is a cross-sectional view of the screen 31 of the third embodiment. In Figure 6, components common to the drawings used in the first embodiment are denoted by the same reference numerals.

[0033] As shown in Figure 6, the screen 31 of this embodiment comprises a wavelength-selective layer 32 having a base material 14 and a plurality of colloidal amorphous materials 15. The wavelength-selective layer 32 has a first layer 33, a second layer 34, and a third layer 35. The first layer 33 is a layer in which a plurality of first colloidal amorphous materials 15B are dispersed in the base material 14 and selectively reflects blue light. The second layer 34 is a layer in which a plurality of second colloidal amorphous materials 15G are dispersed in the base material 14 and selectively reflects green light. The third layer 35 is a layer in which a plurality of third colloidal amorphous materials 15R are dispersed in the base material 14 and selectively reflect red light. In other words, the wavelength-selective layer 32 has a structure in which three layers of base material 14, each containing a different type of colloidal amorphous material 15B, 15G, and 15R, are laminated together.

[0034] The three layers are arranged in the order of the first layer 33, the second layer 34, and the third layer 35, starting from the first surface 32a on the observation side of the wavelength-selective layer 32. The base material 14 constituting the first layer 33, the second layer 34, and the third layer 35 is preferably made of the same material, but may be made of different materials. Furthermore, the three layers 33, 34, and 35 may be bonded to each other using an optical adhesive, or they may not be bonded to each other and may be supported by any support member.

[0035] (Effects of the third embodiment) In this embodiment as well, the same effects as in the first embodiment can be obtained, such as the ability to realize a screen 31 that is less prone to variations in contrast and color depending on the viewing angle, because the wavelength-selective layer 32 has colloidal amorphous material 15.

[0036] Furthermore, in this embodiment, a wavelength-selective layer 32 is used, which is made up of three layers of base material 14 in which different types of colloidal amorphous materials 15B, 15G, and 15R are dispersed. This makes it easier to uniformly disperse each colloidal amorphous material 15B, 15G, and 15R in each layer 33, 34, and 35, and simplifies the manufacturing process of the wavelength-selective layer 32.

[0037] Furthermore, during the manufacturing process of the wavelength-selective layer 32, minute impurities or air bubbles may be mixed into the base material 14, and these impurities or air bubbles may scatter the projected light L. Considering this point, since blue light, which has the shortest wavelength among the three colors of light, is the most easily scattered, a configuration in which the first layer 33 that reflects the most easily scattered blue light is placed on the observation side can improve the utilization efficiency of the projected light L.

[0038] [Fourth Embodiment] A fourth embodiment of the present invention will be described below with reference to Figure 7. Since the basic configuration of the screen in this embodiment is the same as in the first embodiment, a description of the common parts will be omitted. Figure 7 is a cross-sectional view of the screen 41 of the fourth embodiment. In Figure 7, components common to the drawings used in the first embodiment are denoted by the same reference numerals.

[0039] As shown in Figure 7, the screen 41 of this embodiment comprises a wavelength-selective layer 17, a substrate 42, and an anti-reflective layer 43. The substrate 42 is provided on the second surface 17b of the wavelength-selective layer 17. The anti-reflective layer 43 is provided on the first surface 17a of the wavelength-selective layer 17. The wavelength-selective layer 17 comprises a base material 14 and a plurality of colloidal amorphous materials 15, including a first colloidal amorphous material 15B, a second colloidal amorphous material 15G, and a third colloidal amorphous material 15R. The wavelength-selective layer 17 can also be replaced with the wavelength-selective layer 23 in the second embodiment or the wavelength-selective layer 32 in the third embodiment.

[0040] The substrate 42 may be light-transmitting. For example, it is composed of a light-transmitting resin film such as polyethylene terephthalate (PET), a glass substrate, etc. The anti-reflective layer 43 is composed of, for example, a dielectric multilayer film. The transmittance of the screen 41 is preferably 50% or more, and more preferably 70% or more.

[0041] (Effects of the fourth embodiment) In this embodiment as well, the same effects as in the first embodiment can be obtained, such as the realization of a screen 41 that is less prone to variations in contrast and color depending on the viewing angle, because the wavelength-selective layer 17 has colloidal amorphous material 15.

[0042] According to the configuration of this embodiment, since the screen 41 is equipped with a base material 42, the wavelength-selective layer 17 can be supported by the base material 42. This increases the mechanical strength of the screen 41 and makes it easier to handle. In addition, since the screen 41 is equipped with an anti-reflective layer 43 on the first surface 17a of the wavelength-selective layer 17, surface reflection of the screen 41 is suppressed, and the visibility of the projected image can be improved.

[0043] [Fifth Embodiment] A fifth embodiment of the present invention will be described below with reference to Figure 8. Since the basic configuration of the screen in this embodiment is the same as in the first embodiment, a description of the common parts will be omitted. Figure 8 is a cross-sectional view of the screen 51 of the fifth embodiment. In Figure 8, components common to those used in previous embodiments are denoted by the same reference numerals.

[0044] As shown in Figure 8, the screen 51 of this embodiment comprises a wavelength-selective layer 17, a substrate 42, a light-diffusing layer 52, and an anti-reflective layer 43. The light-diffusing layer 52 is provided between the second surface 17b of the wavelength-selective layer 17 and the substrate 42. The anti-reflective layer 43 is provided on the first surface 17a of the wavelength-selective layer 17. The wavelength-selective layer 17 comprises a base material 14 and a plurality of colloidal amorphous materials 15, including a first colloidal amorphous material 15B, a second colloidal amorphous material 15G, and a third colloidal amorphous material 15R. The wavelength-selective layer 17 can also be replaced with the wavelength-selective layer 23 in the second embodiment or the wavelength-selective layer 32 in the third embodiment.

[0045] The light diffusion layer 52 has a structure in which, for example, multiple particles with different refractive indices from the transparent resin are dispersed in a transparent resin. Alternatively, it may be a layer having a fine uneven structure for scattering light. The light diffusion layer 52 is provided on the second surface 17b of the wavelength-selective layer 17 and diffuses the blue light, green light, and red light contained in the projected light L. The half-gain value of the screen 51 is preferably 45 degrees or more, and more preferably 60 degrees or more.

[0046] (Effects of the fifth embodiment) In this embodiment as well, the same effects as in the first embodiment can be obtained, such as the fact that the wavelength-selective layer 17 has colloidal amorphous material 15, which makes it possible to realize a screen 51 that is less prone to variations in contrast and color depending on the viewing angle.

[0047] According to the configuration of this embodiment, since a light diffusion layer 52 is provided on the second surface 17b of the wavelength-selective layer 17, the light reflected by each colloidal amorphous 15B, 15G, and 15R and traveling toward the second surface 17b of the wavelength-selective layer 17 is diffused by the light diffusion layer 52 and emitted from the first surface 17a of the wavelength-selective layer 17 toward the observation side. This makes it possible to realize a screen 51 that allows for the viewing of a bright image over a wide viewing angle.

[0048] [Sixth Embodiment] A sixth embodiment of the present invention will be described below with reference to Figure 9. Since the basic configuration of the screen in this embodiment is the same as in the first embodiment, a description of the common parts will be omitted. Figure 9 is a cross-sectional view of the screen 61 of the sixth embodiment. In Figure 9, components common to those used in previous embodiments are denoted by the same reference numerals.

[0049] As shown in Figure 9, the screen 61 of this embodiment comprises a wavelength-selective layer 17, a substrate 42, a light-absorbing layer 62, and an anti-reflective layer 43. The light-absorbing layer 62 is provided between the second surface 17b of the wavelength-selective layer 17 and the substrate 42. The anti-reflective layer 43 is provided on the first surface 17a of the wavelength-selective layer 17. The wavelength-selective layer 17 comprises a base material 14 and a plurality of colloidal amorphous materials 15, including a first colloidal amorphous material 15B, a second colloidal amorphous material 15G, and a third colloidal amorphous material 15R. The wavelength-selective layer 17 can also be replaced with the wavelength-selective layer 23 in the second embodiment or the wavelength-selective layer 32 in the third embodiment.

[0050] The light-absorbing layer 62 is made of a light-absorbing material such as carbon, polydopamine, or black resin. The light-absorbing layer 62 is provided on the second surface 17b of the wavelength-selective layer 17 and preferably absorbs light in wavelength bands other than blue, green, and red light contained in the projected light L emitted from the projection device 12, but it may also be made of a material that absorbs all visible light. The half-gain value of the screen 61 is preferably 45 degrees or higher, and more preferably 60 degrees or higher.

[0051] (Effects of the sixth embodiment) In this embodiment as well, the same effects as in the first embodiment can be obtained, such as the fact that the wavelength-selective layer 17 has colloidal amorphous material 15, which makes it possible to realize a screen 61 that is less prone to variations in contrast and color depending on the viewing angle.

[0052] According to the configuration of this embodiment, since the light absorption layer 62 is provided on the second surface 17b of the wavelength-selective layer 17, unwanted light such as ambient light that passes through the wavelength-selective layer 17 is absorbed by the light absorption layer 62. This makes it possible to provide a screen 61 that allows for the viewing of high-contrast images.

[0053] It should be noted that the technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. In the above embodiment, an example was given in which the wavelength-selective layer has three types of colloidal amorphous materials, including a first colloidal amorphous material, a second colloidal amorphous material, and a third colloidal amorphous material. However, instead of this configuration, the wavelength-selective layer may have at least two types of colloidal amorphous materials.

[0054] In the third embodiment described above, an example was given in which the wavelength-selective layer is composed of three layers. However, instead of this configuration, the wavelength-selective layer may be composed of two layers. In this case, the wavelength-selective layer may have a first layer containing any two of the first colloidal amorphous material, the second colloidal amorphous material, and the third colloidal amorphous material, and a second layer containing the remaining one.

[0055] In the above embodiment, an example was shown in which the screen is an independent component that can be moved depending on the location of use. However, instead of this configuration, the screen may be directly formed in a location where it is to be permanently installed, such as the wall of a conference room. In this case, a liquid base material containing colloidal amorphous material can be applied to the desired location on the wall and allowed to harden. If the wall surface is a light-diffusing surface, a screen that allows for the viewing of bright images can be realized, as in the fifth embodiment above. If the wall surface is a light-absorbing surface such as black, a screen that allows for the viewing of high-contrast images can be realized, as in the sixth embodiment above.

[0056] Furthermore, the specific details regarding the materials, composition, and arrangement of each component of the screen are not limited to the embodiments described above and can be modified as appropriate. Additionally, layers other than those disclosed above may be interposed between the layers constituting the screen. Moreover, although the above description assumes the application of the present invention to a reflective screen, the present invention may also be applied to a transmissive screen.

[0057] [Summary of this disclosure] A summary of this disclosure is provided below.

[0058] (Note 1) A screen for a projection device that emits projection light including a first light in a first wavelength band and a second light in a second wavelength band different from the first wavelength band, The device comprises a wavelength-selective layer having a translucent base material and a plurality of colloidal amorphous materials dispersed in the base material, A projection screen comprising a plurality of colloidal amorphous materials, the first colloidal amorphous material exhibiting a first structural color corresponding to the first wavelength band, and the second colloidal amorphous material exhibiting a second structural color corresponding to the second wavelength band.

[0059] According to the configuration described in Appendix 1, the wavelength-selective layer has multiple colloidal amorphous materials, including a first colloidal amorphous material and a second colloidal amorphous material, making it possible to create a screen that is less prone to variations in contrast and color due to viewing angle.

[0060] (Note 2) The projected light further includes a third light in a third wavelength band different from the first and second wavelength bands, The plurality of colloidal amorphous materials further include a third colloidal amorphous material exhibiting a third structural color corresponding to the third wavelength band, The projection screen according to Appendix 1, wherein the first structural color is blue, the second structural color is green, and the third structural color is red.

[0061] According to the configuration described in Appendix 2, a screen compatible with a projection device that projects full-color images can be provided.

[0062] (Note 3) The projection screen according to Appendix 2, wherein the wavelength-selective layer further comprises light-absorbing particles that absorb light in wavelength bands other than the first wavelength band, the second wavelength band, and the third wavelength band.

[0063] According to the configuration described in Appendix 3, since the wavelength-selective layer has light-absorbing particles, unwanted light other than the projected light emitted from the projection device, such as ambient light, is absorbed by the light-absorbing particles, thereby increasing the contrast of the image.

[0064] (Note 4) The projection screen according to Appendix 2 or Appendix 3, wherein the wavelength-selective layer is composed of a single layer of the matrix material in which the first colloidal amorphous material, the second colloidal amorphous material, and the third colloidal amorphous material are dispersed.

[0065] According to the configuration described in Appendix 4, unlike cases where the wavelength-selective layer is composed of multiple layers, there is no interface with the base material inside the wavelength-selective layer. Therefore, light loss is reduced, and a screen with high light utilization efficiency can be realized.

[0066] (Note 5) The wavelength-selective layer comprises a first layer in which the first colloidal amorphous material is dispersed in the base material, a second layer in which the second colloidal amorphous material is dispersed in the base material, and a third layer in which the third colloidal amorphous material is dispersed in the base material, wherein the projection screen is as described in Appendix 2 or Appendix 3.

[0067] According to the configuration described in Appendix 5, multiple colloidal amorphous materials can be uniformly dispersed in each of the first, second, and third layers, thereby facilitating the manufacturing process of the wavelength-selective layer.

[0068] (Note 6) The projection screen described in Appendix 5, wherein the observation side of the wavelength-selective layer is designated as the first surface, and the layers are arranged in the order of the first layer, the second layer, and the third layer from the first surface.

[0069] According to the configuration described in Appendix 6, if minute impurities or air bubbles are mixed into the matrix material of the wavelength-selective layer, blue light is most easily scattered by these impurities and air bubbles. Therefore, if the first layer, which reflects blue light, is placed on the observation side, the light utilization efficiency can be increased.

[0070] (Note 7) A projection screen according to any one of the appendices 2 to 6, wherein, when the observation side of the wavelength-selective layer is designated as the first surface, an anti-reflective coating is provided on the observation side of the first surface.

[0071] According to the configuration described in Appendix 7, since the screen has an anti-reflective layer on the first surface of the wavelength-selective layer, surface reflection of the screen is suppressed, and the visibility of the projected image can be improved. (Note 8) A projection screen according to any one of the appendices 2 to 7, wherein the side of the wavelength-selective layer opposite to the observation side is designated as the second surface, and the screen further comprises a light-diffusing layer provided on the second surface for diffusing the first light, the second light, and the third light.

[0072] According to the configuration described in Appendix 8, since a light-diffusing layer is provided on the second surface of the wavelength-selective layer, the light reflected by each colloidal amorphous material and traveling towards the second surface of the wavelength-selective layer is diffused by the light-diffusing layer. This makes it possible to realize a screen in which a bright image can be viewed over a wide viewing angle.

[0073] (Note 9) A projection screen according to any one of the appendices 2 to 7, wherein the side of the wavelength-selective layer opposite to the observation side is designated as the second surface, and the screen further comprises a light-absorbing layer provided on the second surface that absorbs light in wavelength bands other than the first wavelength band, the second wavelength band, and the third wavelength band, or all visible light.

[0074] According to the configuration described in Appendix 9, a light absorption layer is provided on the second surface of the wavelength-selective layer. As a result, unwanted light such as ambient light that passes through the wavelength-selective layer is absorbed by the light absorption layer. This makes it possible to create a screen that allows for the viewing of high-contrast images.

[0075] (Note 10) A reflective screen as described in any one of the items from Appendix 1 to Appendix 9, A projection device that emits the projected light toward the reflective screen, A projection system equipped with [the following features].

[0076] According to the configuration described in Appendix 10, a projection system with superior display quality can be provided. [Explanation of Symbols]

[0077] 10…Projection system, 11,21,31,41,51,61…Screen, 12…Projection device, 14…Matrix material, 15…Colloidal amorphous material, 15B…First colloidal amorphous material, 15G…Second colloidal amorphous material, 15R…Third colloidal amorphous material, 17,23,32…Wavelength selective layer, 22…Light absorbing particles, 33…First layer, 34…Second layer, 35…Third layer, 52…Light diffusing layer, 62…Light absorbing layer, L…Projected light.

Claims

1. A screen for a projection device that emits projection light including a first light in a first wavelength band and a second light in a second wavelength band different from the first wavelength band, The device comprises a wavelength-selective layer having a translucent base material and a plurality of colloidal amorphous materials dispersed in the base material, A projection screen comprising a plurality of colloidal amorphous materials, the first colloidal amorphous material exhibiting a first structural color corresponding to the first wavelength band, and the second colloidal amorphous material exhibiting a second structural color corresponding to the second wavelength band.

2. The projected light further includes a third light in a third wavelength band different from the first and second wavelength bands, The plurality of colloidal amorphous materials further include a third colloidal amorphous material that exhibits a third structural color corresponding to the third wavelength band. The projection screen according to claim 1, wherein the first structural color is blue, the second structural color is green, and the third structural color is red.

3. The projection screen according to claim 2, wherein the wavelength-selective layer further comprises light-absorbing particles that absorb light in wavelength bands other than the first wavelength band, the second wavelength band, and the third wavelength band.

4. The projection screen according to claim 2 or 3, wherein the wavelength-selective layer is composed of a single layer of the base material in which the first colloidal amorphous material, the second colloidal amorphous material, and the third colloidal amorphous material are dispersed.

5. The projection screen according to claim 2 or 3, wherein the wavelength-selective layer comprises a first layer in which the first colloidal amorphous material is dispersed in the base material, a second layer in which the second colloidal amorphous material is dispersed in the base material, and a third layer in which the third colloidal amorphous material is dispersed in the base material.

6. The projection screen according to claim 5, wherein, when the observation side of the wavelength-selective layer is designated as the first surface, the first layer, the second layer, and the third layer are arranged in that order from the first surface.

7. The projection screen according to claim 2 or 3, wherein, when the observation side of the wavelength-selective layer is designated as the first surface, an anti-reflective coating is provided on the observation side of the first surface.

8. The projection screen according to claim 2 or 3, wherein the side of the wavelength-selective layer opposite to the observation side is designated as the second surface, and the screen further comprises a light-diffusing layer provided on the second surface for diffusing the first light, the second light, and the third light.

9. The projection screen according to claim 2 or 3, wherein, when the side of the wavelength-selective layer opposite to the observation side is designated as the second surface, the screen further comprises a light-absorbing layer provided on the second surface that absorbs light in wavelength bands other than the first wavelength band, the second wavelength band, and the third wavelength band, or all visible light.

10. A projection screen according to claim 1 or claim 2, A projection device that emits the projected light toward the projection screen, A projection system equipped with [the following features].

Images