JP7435185B2 - Reflective screen, video display system - Google Patents

Description

The present invention relates to a reflective screen and an image display system that display an image by reflecting irradiated image light.

2. Description of the Related Art Conventionally, ideas have been proposed regarding image display systems that display various images by irradiating image light onto a reflective screen.
Regarding reflective screens applied to such video display systems, Patent Documents 1 to 3 propose a method of reducing reflection of external light and improving contrast by providing a light absorption layer.

Japanese Patent Application Publication No. 6-75304 Japanese Patent Application Publication No. 9-133969 Japanese Patent Application Publication No. 2008-170607

However, in this type of video display system, it is desired to further reduce reflection of external light and improve contrast.

The present invention has been made in consideration of the above points, and an object of the present invention is to provide a reflective screen and an image display system that can reduce reflection of external light and improve contrast.

The present invention solves the above problems by the following solving means. Note that, in order to facilitate understanding, the description will be given with reference numerals corresponding to the embodiments of the present invention, but the present invention is not limited thereto.

The first invention is a reflective screen that enables observation by reflecting image light of red, green, and blue laser beams projected from an image source (LS), which comprises a base material layer (24, 524); A lens layer (23) in which a Fresnel lens shape is formed on the back side opposite to the image source side of the base layer, and a reflective layer (22, 522) provided on the back side of the lens layer. The reflective screen (10, 120, 220, 320, 420, 520) is characterized in that a light absorbing portion having wavelength selectivity is provided closer to the image source than the reflective layer.
A second invention is characterized in that in the reflective screen of the first invention, the light absorption portion is formed of the base layer (24, 242) containing a material having wavelength selectivity. A reflective screen (10).
A third invention is a reflective screen according to the first invention, characterized in that the light absorption portion is formed by the lens layer (123) containing a material having wavelength selectivity. 120).
A fourth invention is the reflective screen according to any one of the first to third inventions, wherein the light absorption portion has a light absorption band in a wavelength band that does not include the wavelengths of the red, green, and blue laser beams. The reflective screen (10, 120) is characterized in that it contains materials (A to D) having multiple types of wavelength selectivity.
A fifth invention is the reflective screen of the first invention, in which the light absorption section contains a material having wavelength selectivity, and the light absorption layer (22) is provided closer to the image source than the reflection layer (22). 225, 326, 426).
A sixth invention is the reflective screen according to the fifth invention, in which the light absorption layer (225, 326, 426) has a light absorption band in a wavelength band that does not include the wavelengths of the red, green, and blue laser beams. The reflective screen (220, 320, 420) is characterized by containing materials (A to D) having multiple types of wavelength selectivity.
A seventh invention is the reflective screen according to the sixth invention, wherein the light absorption layer (326) is a stack of a plurality of absorption layers (326a to 326d) containing materials (A to D) having different wavelength selectivities. A reflective screen (320) characterized by:
An eighth invention is the reflective screen according to the fifth invention or the sixth invention, wherein the light absorption layer (426) has a red region (R) that selectively transmits the image light generated by the red laser light; A green region (G) that selectively transmits the image light produced by the green laser light and a blue region (B) that selectively transmits the image light produced by the blue laser light are patterned. This is a reflective screen (420).
A ninth invention provides that, in the reflective screen of the first invention, when the spectral reflectance of the reflective screen is measured, the laser beams of red, green, and blue are reflected within a range of ±50 nm centered on the wavelengths of the laser beams. 5. A reflective screen (520) characterized by having a maximum value of coefficient.
A tenth invention is the reflective screen according to the ninth invention, in which the light absorption section (242) has an average reflectance PA at the wavelengths of the red, green, and blue laser beams, and has a reflectance in the visible light region. The reflective screen (520) is characterized by satisfying the relationship PA/PB≧1.16, where PB is the average value of the reflectance of the wavelength of light and PA/PB is the ratio of these.
An eleventh invention is the reflective screen of the ninth invention or the tenth invention, in which the color difference ΔE ^* ab between the chromaticity of black display and the chromaticity of an achromatic color serving as a reference satisfies ΔE ^* ab≦2.4. A reflective screen (520) characterized by:
A twelfth invention provides a video display system (10) comprising a reflective screen (10) according to any one of the first to eleventh inventions, and a video source (LS) that irradiates the reflective screen with video light. ).

According to the present invention, it is possible to reduce the reflection of external light and improve the contrast of images.

FIG. 1 is a diagram illustrating a video display system according to a first embodiment. It is a figure explaining the layer structure of the reflective screen of a 1st embodiment. It is a figure explaining the detail of the lens layer and the reflective layer of 1st Embodiment. FIG. 3 is a characteristic curve diagram showing optical characteristics of a material having wavelength selectivity contained in a light absorption part. It is a figure explaining the layer structure of the reflective screen of 2nd Embodiment. It is a figure explaining the layer structure of the reflective screen of 3rd Embodiment. It is a figure explaining the layer structure of the reflective screen of 4th Embodiment. It is a figure explaining the layer structure of the reflective screen of 5th Embodiment. It is a partially enlarged view of the light absorption layer of a 5th embodiment seen from the observer side. It is a figure which shows another form of the light absorption layer of 5th Embodiment. It is a figure explaining the layer structure of reflective screen 520 of a 6th embodiment. 5 is a diagram illustrating a surface layer 525. FIG. 3 is a diagram showing the measurement results of the spectral reflectance of the reflective screens of measurement examples 1 to 4. FIG. 3 is a diagram showing the measurement results of spectral reflectance at point A of the reflective screen in Measurement Examples 1 to 5. FIG.

Embodiments of the present invention will be described below with reference to the drawings and the like.
Note that each figure shown below, including FIG. 1, is a schematic diagram, and the size and shape of each part are appropriately exaggerated for easy understanding.
In this specification, words such as plate, sheet, etc. are used, but these are generally used in the order of thickness, such as plate, sheet, and film. Among them, it is used in accordance with that. However, since there is no technical meaning in these different uses, these words can be replaced as appropriate.
Numerical values such as dimensions and material names of each member described in this specification are examples of embodiments, and are not limited to these, and may be appropriately selected and used.
In this specification, terms that specify shapes or geometrical conditions, such as terms such as parallel and orthogonal, do not have a strict meaning, but also have a similar optical function and are used to the extent that they can be considered parallel or orthogonal. This also includes states with errors.

[First embodiment]
Embodiments of the present invention will be described below with reference to the drawings and the like.
FIG. 1 is a diagram illustrating a video display system 1 of this embodiment. FIG. 1(a) is a perspective view of the video display system 1, and FIG. 1(b) is a side view of the video display system 1.

As shown in FIG. 1, the video display system 1 includes a reflective screen unit 10 including a reflective screen 20, a video source LS, and the like. The video display system 1 of this embodiment emits video light L from the video source LS toward the reflective screen 20, and displays a desired video by reflecting the video light L by the reflective screen 20.
This video display system 1 can be used, for example, as a front projection television system in which the video source LS is provided on the observer O side of the reflective screen 20.

The image source LS is an image light projection device that projects the image light L onto the reflective screen 20. In use, when the screen of the reflective screen 20 is viewed from the normal direction (the normal direction of the screen surface), the video source LS is located at the center in the left-right direction of the reflective screen 20 and located at the center of the screen of the reflective screen 20 . (display area).
The image source LS is located at a position where the distance from the reflective screen 20 in the direction perpendicular to the screen of the reflective screen 20 (thickness direction of the reflective screen 20) is much closer than that of a conventional general-purpose projector or a general-purpose short focus projector. (For example, the distance from the image source LS to the reflective screen 20 is about 300 mm) is an ultra-short focus projector that projects image light L. That is, the image source LS has a shorter projection distance to the reflective screen 20 and a larger incident angle of the image light L to the screen surface of the reflective screen 20 than a conventional general-purpose projector or a short focus projector.

Conventionally, when a general-purpose projector or short-focus projector is used as an image source, the distance between the image source and the reflective screen needs to be 1 m to several meters or more. There were cases where the video display was blocked by people crossing the road. Furthermore, a sufficiently large room is required to install the video sources and reflective screens at such spacing.
On the other hand, since the video display system 1 of the present embodiment uses an ultra-short throw projector as the video source LS as described above, the distance between the video source LS and the reflective screen 20 is significantly increased as described above. The above problem can be solved.
The image source LS of this embodiment uses red, green, and blue laser light sources to emit image light L of red, green, and blue laser beams.

The reflective screen 20 is a screen that reflects the image light L emitted from the image source LS toward the observer O and displays an image. In use, the observation screen of the reflective screen 20 has a substantially rectangular shape with the long side direction being the left-right direction of the screen when viewed from the observer O side.
In the following description, unless otherwise specified, the screen vertical direction, screen horizontal direction, and thickness direction refer to the screen vertical direction (vertical direction), screen horizontal direction (horizontal direction), and thickness when this reflective screen 20 is in use. direction (depth direction).
This reflective screen 20 has a large screen (display area) of, for example, 100 inches or 120 inches diagonally.

The image display system 1 of this embodiment includes an image source LS that is an ultra-short focus projector, and a reflective screen 20 that reflects image light emitted from the image source LS and displays an image. However, the image source LS is not limited to this, and the image source LS may be a conventional general-purpose projector or a short-throw projector that has a longer irradiation distance and a smaller irradiation angle of image light (i.e., incident angle of image light on the screen) than an ultra-short throw projector. A focal projector may be used, and the reflective screen 20 may correspond to such an image source LS.

As shown in FIG. 1, the reflective screen unit 10 includes a reflective screen 20, a flat support plate 30 disposed on the back side of the reflective screen 20, and a bonding layer 40. The reflective screen 20 and the support plate 30 are integrally joined via a joining layer 40.

The material of the support plate 30 is not particularly limited as long as it has high rigidity, but for example, a plate made of metal such as aluminum or a plate made of resin such as acrylic resin is preferably used. In addition, metal plates (so-called honeycomb panels) are made of thin plates such as aluminum on the front and back sides, and have a honeycomb structure formed of thin plates such as aluminum as the internal core material, which reduces the weight of the plate as a whole. etc. may also be used. Further, the support plate 30 is preferably a member that does not have light transmittance, from the viewpoint of preventing reflection of external light and reduction in contrast due to external light.

The thickness of the support plate 30 is preferably 0.2 to 5.0 mm, more preferably 1.0 to 3.0 mm. When the thickness is thinner than 0.2 mm, the rigidity sufficient to support flatness is insufficient, and when it is thicker than 5.0 mm, there is a problem that the weight of the support plate 30 becomes heavy.
The reflective screen 20 is thin and often does not have sufficient rigidity alone to maintain flatness. Therefore, the reflective screen 20 is integrally joined to the support plate 30 to maintain the flatness of the screen.

The bonding layer 40 is a layer that has the function of bonding the reflective screen 20 and the support plate 30 together. The bonding layer 40 is formed using an adhesive, an adhesive, or the like.

FIG. 2 is a diagram illustrating the layer structure of the reflective screen 20 of this embodiment.
In FIG. 2, the line passes through point A (see FIGS. 1(a) and (b)), which is the geometric center (center of the screen) of the observation screen (display area) of the reflective screen 20, and is parallel to the vertical direction of the screen. , a part of the cross section perpendicular to the screen surface (parallel to the thickness direction) is shown enlarged.
As shown in FIG. 2, the reflective screen 20 includes a surface layer 25, a base material layer 24, a lens layer 23, and a reflective layer 22 in order from the image source side (observer side) in its thickness direction.

The base material layer 24 is a sheet-like member that serves as a base material for forming the lens layer 23. A surface layer 25 is integrally formed on the image source side of this base layer 24, and a lens layer 23 is integrally formed on the back side (rear surface side).
The base material layer 24 has a light diffusion layer 241 containing a diffusing agent and a colored layer 242 that absorbs light of a specific wavelength. The base material layer 24 of this embodiment is formed by integrally laminating the light diffusion layer 241 and the colored layer 242 by co-extrusion molding.
In this embodiment, as shown in FIG. 2, in the base material layer 24, the light diffusion layer 241 is located on the back side, and the colored layer 242 is located on the image source side, that is, the surface of the lens layer 23 on the image source side. A light diffusion layer 241 and a colored layer 242 are laminated in this order.

The light diffusion layer 241 is a layer that has a base material made of a light-transmitting resin and contains a diffusing agent that diffuses light. The light diffusion layer 241 has the function of widening the viewing angle and improving the in-plane uniformity of brightness.
The resin that is the base material of the light diffusion layer 241 is, for example, PET (polyethylene terephthalate) resin, PC (polycarbonate) resin, MS (methyl methacrylate styrene) resin, MBS (methyl methacrylate butadiene styrene) resin, TAC ( Triacetyl cellulose) resin, PEN (polyethylene naphthalate) resin, acrylic resin, etc. are preferably used.

As the diffusing agent included in the light diffusing layer 241, particles made of resin such as acrylic resin, epoxy resin, silicone resin, or inorganic particles are preferably used. Note that the diffusing agent may be a combination of an inorganic diffusing agent and an organic diffusing agent. This diffusing agent is preferably approximately spherical and has an average particle size of about 1 to 50 μm. Further, the particle size range of the diffusing agent suitable for use is preferably 5 to 30 μm.
The thickness of the light diffusion layer 241 is preferably about 100 to 2000 μm, although it depends on the screen size of the reflective screen 20 and the like. It is desirable that the light diffusion layer 241 has a haze value in the range of 85 to 99%.

The colored layer 242 is a light absorption section that transmits light in a specific wavelength band among the incident light and absorbs the rest. More specifically, the colored layer 242 selectively transmits red, green, and blue laser light emitted from the image source LS without absorbing much of it, but it selectively transmits light in other wavelength bands (mainly visible light). ) to absorb. Therefore, the colored layer 242 can absorb unnecessary light such as external light without absorbing much of the image light emitted from the image source, and can improve the contrast of the image.

As the resin serving as the base material of the colored layer 242, PET resin, PC resin, MS resin, MBS resin, TAC resin, PEN resin, acrylic resin, etc. can be used.
The light absorbent contained in the base material of the colored layer (light absorption part) 242 is made of a material having wavelength selectivity, such as an azo structure, a phthalocyanine structure, a quinacridone structure, an anthraquinone structure, an indoline structure, or an indoline structure. Dyes containing a danthrone structure, perylene structure, porphyrin structure, squarylium structure, thiophene structure, etc. can be applied.
In this embodiment, the colored layer (light absorption section) 242 has multiple types of wavelength selectivity, with light absorption bands in wavelength bands that do not include the wavelengths of the red, green, and blue laser beams related to the image light L. It is formed by mixing a material (light absorber) into the base material.

FIG. 4 is a characteristic curve diagram showing the optical characteristics of the wavelength-selective material contained in the light absorption section (colored layer 242). FIGS. 4(a) to 4(d) are diagrams showing the optical properties of wavelength-selective materials A to D contained in the light absorption part, respectively, and the vertical axis indicates the light absorption rate [%]. , the horizontal axis indicates the wavelength of light [nm].

The colored layer (light absorbing portion) 242 of this embodiment includes materials A to D shown in FIGS. 4(a) to 4(d) contained in a resin material serving as a base material.
Material A is a dye having a light absorption band on the short wavelength side of blue laser light LB (wavelength 465 nm), as shown in FIG. 4(a). The peak of the light absorption property of material A is at a wavelength of 402 nm, and the half width of its light absorption rate is 10 to 80 nm. Here, the half-width of light absorption refers to the difference between the value of the wavelength on the short wavelength side and the value of the wavelength on the long wavelength side, which is the half value of the absorption peak.
The material A is not limited to the above examples, and may be a dye having a light absorption band and a peak of light absorption characteristics in a wavelength range shorter than the wavelength of the blue laser beam LB, such as an azomethine compound. , indole-based compounds, cinnamic acid-based compounds, porphyrin-based compounds, etc. can be used, and pyrimidine-based compounds (with a peak wavelength of light absorption of 394 nm) are preferred. As material A, these may be used in appropriate combination.
Material B is a dye having a light absorption band on the long wavelength side of red laser light LR1 (wavelength 638 nm), as shown in FIG. 4(b). The peak of the light absorption property of material B is at a wavelength of 680 nm, and the half width of its light absorption rate is 10 to 80 nm. As for the red laser light, laser light LR2 with a wavelength of 642 nm may be applied.
The material B is not limited to the above example, and a dye having a light absorption band and a peak of light absorption characteristics in a wavelength range on the longer wavelength side than the wavelengths of the red laser beams LR1 and LR2 can be used. Material B is preferably, for example, a phthalocyanine compound (the peak wavelength of light absorption is 680 nm).

As shown in FIG. 4(c), the material C is on the long wavelength side of the green laser beam LG (wavelength 525 nm) and on the short wavelength side of the red laser beam (wavelength 638 nm) LR1, and these laser beams LG, LR1 It is a dye that has a light absorption band between wavelengths of . The peak of the light absorption property of material C is at a wavelength of 594 nm, and the half width of its light absorption rate is 10 to 70 nm.
The material C is not limited to the above example, but has a wavelength range of around 590 nm (570 to 620 nm), which is between the wavelength of the green laser light LG and the wavelength of the red laser light LR1, which is the short wavelength side of the red laser light. A dye having a light absorption band and a peak of light absorption characteristics can be used. For example, a cyanine compound, a diphenyl squarylium processed product, etc. can be used, and a porphyrin compound (the peak wavelength of light absorption is 585 nm) can be used. suitable. As material C, these may be used in appropriate combination.
As shown in FIG. 4(d), material D is on the short wavelength side of the green laser beam LG (wavelength 525 nm) and on the long wavelength side of the blue laser beam (wavelength 465 nm) LB, and these laser beams LB, LG It is a dye that has a light absorption band between wavelengths of . The peak of the light absorption property of material D is at a wavelength of 493 nm, and the half width of its light absorption rate is 10 to 80 nm.
Material D is not limited to the above example, but has a light absorption band and a peak of light absorption characteristics in the wavelength range around 490 nm (480 to 510 nm), which is between the wavelength of blue laser light LB and the wavelength of green laser light LG. For example, a pyrazole-based squarylium compound, a dipyrromethene-based compound, etc. can be used, and a merocyanine-based compound (the peak wavelength of light absorption is 496 nm) is suitable. As material D, these may be used in appropriate combination.
By mixing the materials (A to D) each having a light absorption band in a wavelength band that does not include the wavelengths of the red, green, and blue laser beams related to the image light L, the red color related to the image light L, The colored layer 242 can be formed to selectively transmit green and blue laser beams.

FIG. 3 is a diagram illustrating details of the lens layer 23 and reflective layer 22 of this embodiment.
FIG. 3A shows the lens layer 23 observed from the front direction on the back side, and for ease of understanding, the reflection layer 22 is omitted from the illustration. FIG. 3(b) shows a further enlarged part of the cross section shown in FIG. FIG. 3(c) shows an enlarged perspective view of the lens layer on which the reflective layer is formed. Note that in FIGS. 3(b) and 3(c), the base material layer 24 and the surface layer 25 located on the image source side of the lens layer 23 are omitted for easy understanding.

The lens layer 23 is a light-transmitting layer provided on the back side of the base material layer 24, and has a plurality of unit lenses 231 arranged concentrically around point C, as shown in FIG. It has a circular Fresnel lens shape on its back surface. In this circular Fresnel lens shape, a point C which is its optical center (Fresnel center) is located outside the screen (display area) of the reflective screen 20 and on the lower side of the reflective screen 20.
In the present embodiment, an example will be described in which the lens layer 23 has a circular Fresnel lens shape on its back surface, but the invention is not limited to this, and the unit lenses 231 may be arranged in the vertical direction of the screen along the screen surface, etc. Alternatively, the lens may have a linear Fresnel lens shape.

As shown in FIGS. 2 and 3(b), the unit lenses 231 have a cross section parallel to the direction perpendicular to the screen surface (thickness direction of the reflective screen 20) and parallel to the arrangement direction of the unit lenses 231. The shape is approximately triangular.
The unit lens 231 is convex on the back side and includes a lens surface 232 and a non-lens surface 233 facing the lens surface 232.
In this embodiment, when the reflective screen 20 is in use, the lens surface 232 of the unit lens 231 is located vertically above the non-lens surface 233 with the vertex t in between.

As shown in FIG. 3(b), the angle that the lens surface 232 of the unit lens 231 makes with a surface parallel to the screen surface is α. Further, the angle that the non-lens surface 233 makes with a plane parallel to the screen surface is β (β>α). Further, the arrangement pitch of the unit lenses 231 is P, and the lens height of the unit lenses 231 (the dimension from the apex t in the thickness direction of the screen to the point v that is the bottom of the valley between the unit lenses 231) is h.

To facilitate understanding, in FIG. 2 and the like, the arrangement pitch P and angles α and β of the unit lenses 231 are shown to be constant in the arrangement direction of the unit lenses 231. However, in the unit lenses 231 of this embodiment, although the arrangement pitch P and the like are actually constant, the angle α gradually increases as the distance from point C, which is the Fresnel center, in the arrangement direction of the unit lenses 231 increases. Additionally, the lens height h also fluctuates accordingly. The unit lenses 231 of this embodiment are formed with an array pitch P in the range of 50 to 200 μm, a lens height h in the range of 0.5 to 60 μm, and an angle α of the lens surface 232 in the range of 0.5 to 200 μm. The angle β of the non-lens surface 233 is formed within a range of 45 to 90 degrees.

Note that the arrangement pitch P is not limited to this, and may have a form that gradually changes along the arrangement direction of the unit lenses 231, and may vary depending on the size of a pixel of the image source LS that projects the image light L or the image source. It can be changed as appropriate depending on the projection angle of the LS (the angle of incidence of the image light on the screen surface of the reflective screen 20), the screen size of the reflective screen 20, the refractive index of each layer, etc.

The lens layer 23 is formed on the back surface of the base material layer 24 using an ultraviolet curable resin such as urethane acrylate or epoxy acrylate. Note that the lens layer 23 may be formed of other ionizing radiation curable resin such as electron beam curable resin.
Further, the lens layer 23 may be made of thermoplastic resin, and may be formed by a press molding method or the like depending on the Fresnel lens shape of the lens layer 23. Furthermore, a support layer serving as a base material for the lens layer 23 may be provided, and the lens layer 23 may be formed on the back side of the support layer by the above-mentioned method or the like. In the case of such a lens layer 23, a base material layer 24 or the like may be laminated on the image source side via a bonding layer (not shown) or the like.

The reflective layer 22 is a layer that has the function of reflecting light. This reflective layer 22 has a sufficient thickness to reflect light, and is formed on at least a portion of the lens surface 232 of the unit lens 231.
The reflective layer 22 of this embodiment is formed on the lens surface 232 and the non-lens surface 233, as shown in FIGS. 2 and 3(b). Specifically, the reflective layer 22 is formed to cover the back side of the lens layer 23 and fill the boundary between the unit lenses 231 that are convex toward the back side, that is, the point v that is the bottom of the valley. Thereby, the reflective layer 22 can make the unevenness on the back side of the lens layer substantially flat, and the support plate 30 can be attached more stably via the bonding layer 40.

Here, as described above, the lens height h of the unit lenses 231 changes as it moves away from the point C which is the Fresnel center in the arrangement direction of the unit lenses 231, but at the point v which is the bottom of the valley between each unit lens 231. The thickness of the reflective layer 22 in the thickness direction of the lens layer 23 is formed within the range of 10 to 120% of the lens height h of each unit lens 231 in order to more effectively achieve the above-mentioned effect. It is preferable that

The reflective layer 22 is formed by spray coating the lens surface 232 with a paint (resin) containing a flaky metal thin film 22a having high light reflectivity such as aluminum. The reflective layer 22 has a surface perpendicular to the thickness direction of the scale-shaped metal thin film 22a arranged substantially parallel to the lens surface 232, and properly directs the image light L incident on the lens surface 232 toward the viewer. can be reflected. Here, "substantially parallel" means not only that the plane perpendicular to the thickness direction of the metal thin film 22a is completely parallel to the lens surface 232, but also that the inclination with respect to the lens surface 232 is in the range of -10° to +10°. It also includes certain cases. In addition, the scaly metal thin film 22a means that the metal thin film 22a has a scaly shape (external shape) when viewed from the thickness direction. , including circular shapes, polygonal shapes, irregular shapes obtained by crushing thin films, etc.

Here, the property classification of the scale-like metal thin film includes leafing type, non-leafing type, resin coating type, etc., and each has characteristics such as metallic luster, hiding property, adhesion, and orientation. Although metallic luster is also important, a resin coating type is preferred in consideration of adhesion, orientation, etc.

This metal thin film 22a is laminated in an average of eight or more layers on the lens surface of each of the plurality of unit lenses in order to maintain and improve the reflection efficiency of the image light and to prevent the back side of the reflective layer 22 from being transparent. It is desirable that The reflective layer 22 provided with eight or more layers of the metal thin film 22a described above may be provided on some of the lens surfaces 232 of the plurality of unit lenses 231, or may be provided on all the lens surfaces 232. It may be provided for.

The paint forming this reflective layer 22 is composed of a scale-like metal thin film 22a, a binder, a drying aid, a control agent, and the like. From the viewpoint of ease of application with a spray gun, this paint desirably has a viscosity within the range of 50 to 1000 [cp] (measured at a temperature of 23 degrees Celsius).
The metal thin film 22a is made of aluminum formed into a scale shape, and its thickness is formed in a range of 15 to 150 nm, more preferably in a range of 20 to 80 nm. Further, the metal thin film 22a has an average value of dimensions in the vertical direction and the horizontal direction perpendicular to the thickness direction (hereinafter referred to as vertical dimension and horizontal dimension) equal to the lens height h of the unit lens 231, that is, 0. It is preferable that the thickness is 35 to 78 μm. Here, "equal to the lens height h" means not only when the vertical and horizontal dimensions of the metal thin film are equal to the lens height h, but also when they approximate the lens height h (for example, when the vertical and horizontal dimensions of the metal thin film are equal to the lens height h) -30% to +30%).

Here, if this metal thin film 22a is arranged approximately parallel to the non-lens surface 233, when external light is incident on the non-lens surface 233, the external light is reflected by the non-lens surface 233 and is directed toward the viewer. In this case, it may cause a decrease in the contrast of the image. Therefore, by making the vertical and horizontal dimensions of the metal thin film 22a equal to the lens height h as described above, when the paint is applied to the back side of the lens layer 23, the metal thin film 22a It is possible to suppress the arrangement from being substantially parallel to the surface 233. Thereby, even if external light is incident on the non-lens surface 233, the reflective layer 22 can diffuse it at the end of the metal thin film, and can suppress reflection toward the viewer as much as possible.
The metal thin film 22a is preferably contained in a weight ratio of 3 to 15% based on the total weight of the paint from the viewpoint of ensuring the light reflecting function as a reflective layer.

The binder is a transparent bonding agent made of thermosetting resin, and is a base material forming the reflective layer 22. In this embodiment, a urethane-based thermosetting resin is used as the binder, but the binder is not limited to this, and an epoxy-based thermosetting resin may be used, or an ultraviolet curable resin or the like may be used. It's okay. In addition, the binder may be used as a two-component curing type by adding a curing agent, and if it is a urethane resin, polyisocyanate etc. can be used, and if it is an epoxy resin, amines etc. can be used. can be used.

The drying aid is a solvent that adjusts the drying time of the paint applied to the lens layer to a predetermined time, and is a so-called slow-drying solvent. In this embodiment, the drying aid is included in the paint in a predetermined amount so that the drying time of the paint applied to the back side of the lens layer 23 is approximately one hour. As the drying aid, for example, a mixed solvent of propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether, diisobutyl ketone, and 3-methoxy-1-butyl acetate can be used.

The control agent is a solvent that controls the orientation of the metal thin film 22a contained in the paint. When the control agent is included in the paint, the metal thin film 22a can be arranged substantially parallel to the lens surface 232. As the control agent, for example, silica, alumina, aluminum hydroxide, acrylic oligomer, silicon, etc. can be used.

From the viewpoint of ensuring good light reflection characteristics and the good appearance of the back side of the reflective screen 20, the reflective layer 22 is formed of lenses in the arrangement direction of the unit lenses 231, as shown in FIG. 3(b). It is desirable that the thickness T (film thickness) in the direction perpendicular to the lens surface 232 at the center Q of the surface 232 is in the range of 8 μm≦T≦15 μm.

If the thickness T of the reflective layer 22 is less than 8 μm, the reflectance of the reflective layer 22 will decrease and there is a risk that it will not be able to reflect the image light sufficiently. In the reflective layer 22 exposed on the side, some parts have a coating film and some parts do not, resulting in uneven or blurred appearance, which may impair the appearance of the back side of the reflective screen 20, which is undesirable. .
Further, when the thickness T of the reflective layer 22 is larger than 15 μm, a part of the metal thin film 22a included in the reflective layer 22 is not arranged approximately parallel to the lens surface, and some parts are approximately perpendicular to the lens surface. This is not preferable because it may cause uneven appearance on the back side of the reflective layer 22 and impair the appearance on the back side of the reflective screen 20.

Note that the reflective layer 22 is not limited to the resin containing the above-mentioned scale-shaped metal thin film 22a, but may be formed by vapor deposition or sputtering of a metal material having light reflective properties such as aluminum, silver, or nickel. Alternatively, it may be formed by transferring metal foil or the like. In this case, since the thickness of the reflective layer may be very thin (for example, 100 Å), the reflective screen 20 may prevent the image light from passing through to the back side of the reflective layer 22 or the light from the back side passing through the reflective layer 22. From the viewpoint of suppressing light leakage toward the image source side, a light shielding layer may be provided on the back side of the reflective layer 22 to suppress light leakage.

The surface layer 25 is a layer provided on the image source side (observer side) of the base material layer 24. The surface layer 25 of this embodiment forms the outermost surface of the reflective screen 20 on the image source side.
The surface layer 25 of this embodiment has a hard coat function and an anti-glare function, and the surface of the base layer 24 on the image source side is coated with an ultraviolet curable resin (for example, urethane acrylate) having a hard coat function. An ionizing radiation-curable resin is applied to a coating film thickness of approximately 10 to 100 μm, and a fine uneven shape (matte shape) is transferred onto the resin film surface and cured, resulting in a fine uneven shape on the surface. is shaped and formed.

Note that the surface layer 25 is not limited to the above examples, and may have one or more functions selected as appropriate, such as an antireflection function, an antiglare function, a hard coat function, an ultraviolet absorption function, an antifouling function, and an antistatic function. It can be provided as follows. Further, a touch panel layer or the like may be provided as the surface layer 25.
Further, the surface layer 25 may further include a layer having an antireflection function, an ultraviolet absorption function, an antifouling function, an antistatic function, etc., as a separate layer between the surface layer 25 and the base material layer 24.
Further, the surface layer 25 may be a separate layer from the base layer 24 and bonded to the base layer 24 with an adhesive (not shown), or may be opposite to the lens layer 23 of the base layer 24. It may be formed directly on the side (image source side) surface.

Returning to FIG. 2, the state of image light and external light incident on the reflective screen 20 of this embodiment will be described. In FIG. 2, for ease of understanding, it is assumed that the surface layer 25, the colored layer 242, the light diffusion layer 241, and the lens layer 23 have the same refractive index, and the light diffusion layer 241 has the same refractive index for the image light L and the external light G. Diffusion effects and the like are omitted.
As shown in FIG. 2, most of the image light L1 projected from the image source LS enters from below the reflective screen 20, passes through the surface layer 25 and the base layer 24, and passes through the unit lens 231 of the lens layer 23. incident on the
Then, the image light L1 enters the lens surface 232, is reflected by the reflective layer 22, heads toward the viewer O, and exits from the reflective screen 20 in a substantially frontal direction.

At this time, the image light L1 formed from red, green, and blue laser beams can be transmitted through the colored layer 242 containing materials A to D as described above without being almost absorbed. Therefore, since the image light L1 efficiently reaches the observer O, the reflective screen 20 of this embodiment can display images brightly and with good contrast.
Note that since the image light L1 is projected from below the reflective screen 20 and the angle β (see FIG. 3(b)) is larger than the incident angle of the image light L1 at each point in the vertical direction of the reflective screen 20, The image light L1 does not directly enter the non-lens surface 233, and the non-lens surface 233 does not affect the reflection of the image light L1.

On the other hand, as shown in FIG. 2, unnecessary external light G (G1, G2) such as illumination light mainly enters from above the reflective screen 20, passes through the surface layer 25 and the base layer 24, and passes through the lens layer 23. The light enters the unit lens 231 of. Here, most of the unnecessary external light G (G1, G2) such as illumination light in wavelength bands other than red, green, and blue is absorbed in the colored layer 242, and becomes red, green, and blue. Light in this wavelength band mainly enters the unit lens 231.
A part of the external light G1 that has entered the unit lens 231 enters the non-lens surface 233, but is diffused at the end of the metal thin film 22a of the reflective layer 22 formed on the back side of the non-lens surface 233, and is not visible to the observer. Even if it reaches the O side, the amount of light is much smaller than the image light L1.
Further, some of the external light G2 is reflected by the lens surface 232 and mainly heads toward the lower side of the reflective screen 20, and does not directly reach the observer O side. It is significantly less than the light L1.
Therefore, in the reflective screen 20, it is possible to suppress a decrease in the contrast of the image due to external light G1, G2, etc.

As described above, the reflective screen 20 of this embodiment has the following effects.
The reflective screen 20 of this embodiment includes a base material layer 24, a lens layer 23 having a Fresnel lens shape formed on the back side of the base material layer 24, and a reflective layer 22 provided on the back side of the lens layer 23. In addition, a light absorbing section (colored layer 242) having wavelength selectivity is provided closer to the image source than the reflective layer 22. Thereby, the reflective screen 20 can reduce reflection of external light and improve contrast.
Furthermore, by forming the light absorbing portion by mixing a material having wavelength selectivity into the colored layer 242 constituting the base material layer 24, the base material layer 24 having the function of the light absorbing portion can be formed by coextrusion molding. It can be created by a simple process such as.
In the reflective screen 20 of this embodiment, the light absorption portion contains a material that has multiple types of wavelength selectivity and has a light absorption band in a wavelength band that does not include the wavelengths of red, green, and blue laser light. . As a result, the reflective screen 20 efficiently reflects the red, green, and blue laser beams projected from the image source toward the viewer, suppressing a decrease in brightness, and eliminating unnecessary external light. Absorption of light and reflection towards the viewer can be suppressed as much as possible.

[Second embodiment]
Next, a reflective screen according to a second embodiment will be explained.
FIG. 5 is a diagram illustrating the layer structure of the reflective screen 120 of the second embodiment, and corresponds to FIG. 2.
In the reflective screen 120 of the second embodiment, as shown in FIG. 5, a light absorbing portion containing a wavelength selective material is provided in the lens layer 123 instead of the colored layer 242 of the base layer 24. This is different from the reflective screen 20 of the first embodiment in this point. Therefore, parts that perform the same functions as those in the first embodiment are given the same reference numerals or suffixes, and redundant explanations will be omitted as appropriate.

The lens layer (light absorption section) 123 is formed in the same shape as in the first embodiment described above. The lens layer 123 of this embodiment is similar to the wavelength-selective materials A to D contained in the colored layer 242 of the first embodiment described above in the resin forming the lens layer 23 described in the first embodiment. It is formed by containing the following materials. Thereby, the lens layer 123 can efficiently transmit the red, green, and blue laser beams projected from the image source, and can absorb light outside the red, green, and blue wavelength bands.
The base material layer 124 is a sheet-like base material that becomes the basis of the reflective screen 120, and in this embodiment, it is composed of a light diffusion layer 241, and the colored layer is omitted.

As described above, the reflective screen 120 of the present embodiment can reduce reflection of external light and improve contrast, similarly to the reflective screen 20 of the first embodiment described above.
Furthermore, by forming the light absorbing portion by mixing a material having wavelength selectivity into the resin constituting the lens layer 123, the lens layer 123 having the function of the light absorbing portion can be created through a simple process. Can be done.
Furthermore, since the reflective screen 120 of the present embodiment can omit the colored layer provided on the base material layer of the first embodiment, the layer structure is simpler than that of the reflective screen 20 of the first embodiment. It is possible to improve manufacturing efficiency and reduce manufacturing costs.

[Third embodiment]
Next, a reflective screen according to a third embodiment will be described.
FIG. 6 is a diagram illustrating the layer structure of the reflective screen 220 of the third embodiment, and corresponds to FIG. 2.
As shown in FIG. 6, the reflective screen 220 of the third embodiment has the second feature that a light absorbing portion containing a material having wavelength selectivity is provided in the surface layer 225 instead of the lens layer 123. This is different from the reflective screen 120 of the embodiment. Therefore, parts that perform the same functions as those in the second embodiment are given the same reference numerals or the same suffixes, and redundant explanations will be omitted as appropriate. In addition, the lens layer 23 of this embodiment is formed with the same structure as the lens layer 23 of 1st Embodiment.
The surface layer (light absorbing portion) 225 is formed in the same shape as in the second embodiment described above. The surface layer 225 of this embodiment is similar to the wavelength-selective materials A to D contained in the lens layer 123 of the second embodiment described above in the resin forming the surface layer 25 described in the first embodiment. It is formed by containing the following materials.

As described above, the reflective screen 220 of this embodiment can reduce reflection of external light and improve contrast, similarly to the reflective screen 120 of the second embodiment described above.
Further, in the reflective screen 220 of this embodiment, the light absorbing portion is formed by mixing a material having wavelength selectivity into the resin constituting the surface layer 225, so that the surface layer 220 having the function of the light absorbing portion can be created by a simple process.
Furthermore, in the reflective screen 220 of this embodiment, since the surface layer 25 contains a material having wavelength selectivity to form a light absorption portion, the specular reflection component on the surface of the reflective screen 20 can be reduced. This makes it possible to reduce so-called ceiling ghosts caused by reflection of external light.

[Fourth embodiment]
Next, a reflective screen according to a fourth embodiment will be described.
FIG. 7 is a diagram illustrating the layer structure of the reflective screen 320 of the fourth embodiment, and corresponds to FIG. 2.
As shown in FIG. 7, the reflective screen 320 of the fourth embodiment has a light absorbing layer containing a material having wavelength selectivity, instead of providing a light absorbing portion containing a material having wavelength selectivity in the lens layer 123. This embodiment is different from the reflective screen 120 of the second embodiment described above in that a (light absorbing section) 326 is separately provided on the back surface of the base layer 124. Therefore, parts that perform the same functions as those in the second embodiment are given the same reference numerals or the same suffixes, and redundant explanations will be omitted as appropriate. In addition, the lens layer 23 of this embodiment is formed with the same structure as the lens layer 23 of 1st Embodiment.

The reflective screen 320 includes a surface layer 25, a base material layer 124, a light absorption layer 326, a lens layer 23, and a reflective layer 22, which are laminated in order from the image source side.
The light absorption layer 326 is a sheet-like member in which a plurality of absorption layers containing materials A to D (see FIGS. 4A to 4D) having different wavelength selectivities are laminated. Specifically, the light absorption layer 326 includes a first absorption layer 326a containing material A having wavelength selectivity, a second absorption layer 326b containing material B having wavelength selectivity, and a material C having wavelength selectivity. Four layers, a third absorption layer 326c containing material D and a fourth absorption layer 326d containing wavelength-selective material D, are laminated in order from the viewer's side.

Each absorption layer (326a to 326d) is made of a material having wavelength selectivity as described above, a resin having light transmittance (for example, PC (polycarbonate) resin, MS (methyl methacrylate styrene) resin, MBS (methyl methacrylate styrene) resin, etc. - It is formed by incorporating it into a butadiene styrene resin, TAC (triacetylcellulose) resin, PEN (polyethylene phthalate) resin, PET (polyethylene terephthalate) resin, PMMA (polymethyl methacrylate) resin, etc. The light absorption layer 326 is formed, for example, by appropriately bonding each absorption layer (326a to 326d) with a bonding layer (not shown) or the like.
Note that the stacking order of the first to fourth absorbent layers (326a to 326d) is not limited to the above-described form, and each layer may be stacked in a different order. Furthermore, although the light absorption layer 326 has been described as an example in which it is disposed on the back surface of the base material layer 124, it is not particularly limited as long as it is closer to the viewer than the reflective layer 22; It may be arranged on the image source side surface, on the image source side surface of the surface layer 25, between the lens layer 23 and the reflective layer 22, or the like.

As described above, the reflective screen 320 of this embodiment can reduce reflection of external light and improve contrast, similarly to the reflective screen 120 of the second embodiment described above.
In addition, in the reflective screen 320 of this embodiment, the light absorption layer 326 is formed of absorption layers (326a to 326d) of materials having a plurality of different wavelength selectivities, so that the light absorption layer 326 can be adjusted depending on the required optical properties etc. The light absorption layer 326 can be set by selecting the absorption layer to be used.

[Fifth embodiment]
Next, a reflective screen according to a fifth embodiment will be explained.
FIG. 8 is a diagram illustrating the layer structure of the reflective screen 420 of the fifth embodiment, and corresponds to FIG. 2.
FIG. 9 is a partially enlarged view of the light absorption layer 426 of the fifth embodiment as viewed from the viewer side.
As shown in FIG. 8, the reflective screen 420 of the fifth embodiment has a light absorbing layer containing a material having wavelength selectivity, instead of providing a light absorbing portion containing a material having wavelength selectivity in the lens layer 123. 426 is separately provided on the back side of the base material layer 124, which is different from the reflective screen 120 of the second embodiment described above. Therefore, parts that perform the same functions as those in the second embodiment are given the same reference numerals or the same suffixes, and redundant explanations will be omitted as appropriate. In addition, the lens layer of this embodiment is formed with the same structure as the lens layer of 1st Embodiment.

The reflective screen 420 includes a surface layer 25, a base material layer 124, a light absorption layer 426, a lens layer 23, and a reflective layer 22, which are laminated in order from the image source side.
As shown in FIG. 9, the light absorption layer 426 is a sheet-like member patterned with a red region R, a green region G, and a blue region B that selectively transmit image light generated by red, green, and blue laser beams, respectively. It is.

Here, in the red region R of the light absorption layer 426, in addition to the materials A to D having wavelength selectivity shown in FIG. It also contains a material that absorbs the wavelength band of , and mainly transmits red laser light LR1 (wavelength 638 nm) and/or LR2 (wavelength 642 nm) among the incident light (visible light).
Similarly, in the green region G of the light absorption layer 426, in addition to the wavelength-selective materials A to D shown in FIG. It also includes a material that absorbs wavelength bands (638 nm, 642 nm), and mainly transmits green laser light LG (wavelength 525 nm) of the incident light.
In the blue region B of the light absorption layer 426, in addition to the wavelength-selective materials A to D shown in FIG. ), and mainly transmits blue laser light LB (wavelength 465 nm) of the incident light.

In the light absorption layer 426 of this embodiment, the red region R, the green region G, and the blue region B are each formed in a rectangular shape with the long side in the vertical direction of the screen, and the red region R, the green region The same color areas are formed in a so-called stripe arrangement in the vertical direction of the screen so that the G and blue areas B are repeated in a circular manner.

Further, in the light absorption layer 426, a black region BL is provided at the boundary of each of these red region R, green region G, and blue region B. By providing this black region BL, the display on the reflective screen 420 is The contrast can be improved by increasing the blackness of the screen.
The black area BL is formed by containing a dark coloring agent such as black in a resin serving as a base material. The colorant forming the black region BL is preferably a dark color dye or pigment such as gray or black, or a metal salt such as carbon black, graphite, or black iron oxide. As the material, PET resin, PC resin, MS resin, MBS resin, TAC resin, PEN resin, acrylic resin, etc. can be used.

Each of the red, green, and blue regions R, G, and B is formed to have a width of, for example, 10 to 400 μm in the vertical direction of the screen and 10 to 400 μm in the horizontal direction of the screen, and the interval between each region (the width of the black region BL) is as follows. For example, it is formed to have a thickness of 5 to 50 μm.
Note that the black area BL may be created in a line shape extending in the vertical direction of the screen or in the horizontal direction of the screen, or may be created in a shape that surrounds the red area R, green area G, and blue area B, respectively. good. Further, the black area BL may be omitted if necessary.
Further, each of the red, green, and blue regions R, G, and B may be formed in a shape other than a rectangular shape, for example, a circular shape or a polygonal shape such as a hexagonal shape.

The light absorption layer 426 is produced, for example, as follows.
The red, green, and blue regions R, G, and B of the light absorption layer 426 can be produced on a transparent base material by applying offset printing, photolithography, an inkjet method, etc. Among them, the inkjet method can be used. , it is convenient to eject ink forming the red, green, and blue regions R, G, and B.
The black area BL can be formed on a transparent substrate by applying a chromium vapor deposition method, a film transfer method, an inkjet method, etc., but the inkjet method is simpler.
When providing the black region BL, the black region BL is formed in advance to serve as a partition wall, and red, green, and blue regions R, G, and B are formed in a matrix-like region partitioned by the partition wall (black region BL). The light absorption layer 426 is produced by discharging ink using an inkjet method to form red, green, and blue regions R, G, and B. Then, the manufactured light absorption layer 246 is bonded to the back surface of the base material layer 124.
Note that the light absorption layer 426 may be formed directly on the back side surface of the base material layer 124 by an inkjet method or the like.

(another form)
FIG. 10 is a diagram showing another form of the light absorption layer of the fifth embodiment, and corresponds to FIG. 9.
The light absorption layer 426 is not limited to the form shown in FIG. 9 described above. For example, as shown in FIG. 10, the light absorption layer 426 is formed in a so-called mosaic arrangement in which a red region R, a green region G, and a blue region B are sequentially and cyclically repeated in the horizontal and vertical directions of the screen. You can also do this.
Further, instead of being arranged regularly, the red region R, the green region G, and the blue region B may be arranged randomly (irregularly).

Although the light absorption layer 426 has been described as an example in which it is disposed on the back side of the base material layer 124, it is not particularly limited as long as it is closer to the viewer than the reflective layer 22. For example, the light absorption layer 426 It may be arranged on the image source side surface of the surface layer 25, on the image source side surface of the surface layer 25, between the lens layer 23 and the reflective layer 22, etc. Note that when the light absorption layer 426 is provided between the lens layer 23 and the reflective layer 22, a black region BL, a red region R, a green region G, and a blue region B are formed on the back side of the lens layer 23 by an inkjet method or the like. Then, a light absorption layer 426 is produced, and a reflection layer 22 is formed on the back side thereof.

As described above, the reflective screen 420 of this embodiment can reduce reflection of external light and improve contrast, similarly to the reflective screen 120 of the second embodiment described above.
In addition, the reflective screen 420 of this embodiment secures sufficient transmittance of image light of red, green, and blue laser beams by patterning red region R, green region G, and blue region B, and sufficiently blocks external light. can be absorbed into.
Furthermore, since the reflective screen 420 of this embodiment has the black area BL provided at the boundary of each area of the red area R, the green area G, and the blue area B, the blackness of the display screen of the reflective screen 420 is increased. can improve contrast.

[Sixth embodiment]
Next, the reflective screen 520 of the sixth embodiment will be described.
FIG. 11 is a diagram illustrating the layer structure of the reflective screen 520 of the sixth embodiment, and corresponds to FIG. 2.
As shown in FIG. 11, the reflective screen 520 of the sixth embodiment has a colored layer 242 (light absorption section) containing a material having wavelength selectivity as a light absorption section, and a base material layer 524 that does not contain a diffusing agent. It is provided on the image source side, the surface layer 525 has an optical shape on the image source side, the reflective layer 522 is formed only on the lens surface 232, and the light shielding layer 527 is provided. , is different from the reflective screen 20 of the first embodiment described above. Therefore, parts that perform the same functions as those in the first embodiment are given the same reference numerals or suffixes, and redundant explanations will be omitted as appropriate. Note that the lens layer 23 of this embodiment is similar to the lens layer 23 of the first embodiment.

The base material layer 524 is a layer having light transmittance and does not contain a diffusing agent. This base material layer 524 can be formed using a resin that is the base material of the light diffusion layer 241 shown in the first embodiment, such as PET (polyethylene terephthalate) resin, PC (polycarbonate) resin, MS Suitable examples include (methyl methacrylate styrene) resin, MBS (methyl methacrylate butadiene styrene) resin, TAC (triacetyl cellulose) resin, PEN (polyethylene naphthalate) resin, and acrylic resin.

The colored layer (light absorption section) 242 is a layer similar to the colored layer 242 of the first embodiment described above, and is a light absorption section that transmits light in a specific wavelength band among incident light and absorbs others. It is.
In this embodiment, the colored layer 242 is provided on the image source side of the base layer 524, but the present invention is not limited to this, and the colored layer 242 may be located on the back side of the base layer 524.

The reflective layer 522 of this embodiment is formed on the lens surface 232, but not on the non-lens surface 233, as shown in FIG. The reflective layer 522 is formed by vapor deposition or sputtering of a metal material having light reflective properties such as aluminum, silver, or nickel, or by transferring a metal foil.
Note that the present invention is not limited to this, and the reflective layer 522 may be formed on the lens surface 232 and the non-lens surface 233.

The light-shielding layer 527 is a layer formed on the back side of the reflective layer 522, and is a layer that fills in the uneven shape formed by the unit lenses 231 and makes the back side surface of the reflective screen 520 planar.
This light-shielding layer 527 has a light-absorbing property, and the image light passes through to the back side from the reflective layer 522, which has a very thin thickness (for example, 100 Å) by vapor deposition, and the light from the back side is reflected. It has the effect of suppressing transmission through the layer 522 to the image source side. It also has the function of protecting the reflective layer 522 from deterioration, damage, peeling, etc.
Note that the light shielding layer 527 may have, for example, an ultraviolet absorption function, an antifouling function, etc., or it does not have light absorption property if there is no problem such as external light entering the reflective screen 520 from the back side. It may also be a form.

FIG. 12 is a diagram illustrating the surface layer 525. 12(a) shows the surface layer 525 observed from the front direction on the image source side, and FIG. 12(b) shows a cross section of the surface layer 525 in a cross section parallel to the screen left-right direction and thickness direction of the reflective screen 520. A part of the image is shown enlarged.
The surface layer 525 of this embodiment has a lenticular lens shape in which unit surface lenses 5251 convex toward the image source are arranged on its image source side surface.

The unit surface lenses 5251 have a partial cylindrical shape, and are arranged in the horizontal direction (X direction) of the screen, with the screen vertical direction (Y direction) as the ridgeline direction (longitudinal direction). Further, the unit surface lens 5251 has a cross-sectional shape shown in FIG. 12, which is a partial circle shape. Note that the shape of the unit surface lens 5251 is not limited to the above, and may be, for example, a partial shape of an elliptical cylinder, or a columnar lens shape consisting of a plurality of curved surfaces.
By providing the surface layer 525 on which such unit surface lenses 5251 are formed, the image light is diffused in the horizontal direction of the screen by the unit surface lenses 5251, and the reflective screen 520 can adjust the viewing angle in the horizontal direction (X direction) of the screen. Sufficient capacity can be secured.

The arrangement pitch P2 of the unit surface lenses 5251 is within the range of 30 to 120 μm, and the height of the unit surface lenses 5251 (the point between the apex of the unit surface lenses 5251 and the bottom of the valley between the unit surface lenses 111 in the thickness direction of the screen) It is preferable that h2 is within the range of 10 to 25 μm from the viewpoint of diffusing the image light in the horizontal direction of the screen and ensuring a sufficient viewing angle in the horizontal direction of the screen. The unit surface lenses 5251 of this embodiment are arranged adjacent to each other, and the lens width W2 and the arrangement pitch P2 are equal, but the invention is not limited to this, and W2>P2 may be satisfied.
The surface layer 525 is formed to have a thickness of 15 to 35 μm.

Further, the unit surface lens 5251 of this embodiment has a rough surface having a fine uneven shape on its image source side (+Z side) surface. When the image source side surface of the surface layer 525 is made rough, it is possible to reduce the reflection of external light such as illumination light and sunlight, and to expand the viewing angle in the vertical direction (Y direction) of the screen. .
Note that the present invention is not limited to this, and the surface of the unit surface lens 5251 may be a smooth surface that does not have the above-mentioned fine unevenness.

The surface layer 525 of this embodiment may be formed using an ultraviolet curable resin such as urethane acrylate or epoxy acrylate, an ionizing radiation curable resin such as an electron beam curable resin, or a heat curable resin. Plastic resin may also be used.
Furthermore, the surface layer 525 is not limited to the above example, and may have another lens shape or may have no lens shape.

In the distribution of spectral reflectance in the visible light region (400 to 700 nm), the reflective screen 520 has a maximum value of reflectance within a region of ±50 nm centered on the wavelengths of red, green, and blue laser beams, respectively. This is preferable from the viewpoint of increasing the contrast of the image and displaying a bright and good image.
In addition, the reflective screen 520 has an average value of reflectance at wavelengths of red, green, and blue laser beams (LR1, LR2, LG, LB) as PA [%], and has a reflectance of 1 nm in the visible light region (400 to 700 nm). When the average value of the spectral reflectance for each is defined as PB [%], it is preferable that the ratio PA/PB, which is the ratio thereof, satisfies PA/PB≧1.16.

When PA/PB<1.16, there is a problem that the contrast of the image decreases or the displayed image becomes dark due to external light entering the reflective screen. Therefore, it is preferable that the ratio PA/PB satisfies PA/PB≧1.16.
The reflective screen 520 of this embodiment has a maximum value of reflectance within a region of ±50 nm centered on the wavelengths of red, green, and blue laser beams (LR1, LR2, LG, LB), respectively. , PA/PB≧1.16.
In addition, in this embodiment, when calculating the average value PA, the above four lights (LB, LG, LR1, LR2) are mentioned as laser lights, but generally, the laser light source of the video source LS is red, green, etc. , a plurality of light sources with one or more wavelengths may be used for each of the three colors of blue. Therefore, the average value PA may be, for example, the average value of the three wavelengths of red, green, and blue laser light (LR1, LG, LB).

Further, in the reflective screen 520, it is preferable that the color difference ΔE ^* ab between the chromaticity of black display and the chromaticity of an achromatic color serving as a reference color satisfies ΔE ^* ab≦2.4. This is because if the color difference ΔE ^* ab>2.4, the color will be biased in black display and will not be visually recognized as an achromatic color. The reflective screen 520 of this embodiment satisfies ΔE ^* ab≦2.4.

The image light and external light incident on the reflective screen 520 of the sixth embodiment will be explained.
As shown in FIG. 11, most of the image light L1 projected from the image source LS is reflected by the reflective layer 522 and goes toward the observer O, similarly to the first embodiment. At this time, the image light L1 formed from red, green, and blue laser beams is hardly absorbed in the colored layer 242. Further, since the light is diffused in the horizontal direction of the screen by the unit surface lens 5251 of the surface layer 525 and exits toward the observer O, a sufficient viewing angle in the horizontal direction of the screen can be ensured.

Most of the external light G (G1, G2) incident on the reflective screen 520 is absorbed by the colored layer 242 in wavelength bands other than red, green, and blue. As in the first embodiment, some of the external light G2 is reflected by the reflective layer 522 and heads toward the lower side of the reflective screen 520, and does not directly reach the observer O, and even if it does, the amount of light G2 does not reach the observer O directly. is significantly smaller than the image light L1. Further, a part of the external light G1 enters the non-lens surface 233 and is absorbed by the light shielding layer 527.
Therefore, even in this embodiment, as in the first embodiment described above, reflection of external light incident on the reflective screen 520 is reduced, the contrast of the displayed image is improved, and a good image is displayed. be able to.

(another form)
As for the light absorbing portion, a material having selective wavelength properties as described above may be kneaded with the material forming the lens layer 23, and the lens layer 23 may be used as the light absorbing portion, or the base material layer 524 may be formed. The base material layer 524 may be used as a light absorbing portion by kneading it into the material. Alternatively, the reflective layer 522 may be formed by kneading a material having wavelength selectivity with the material containing the metal thin film described in the first embodiment, and the reflective layer may be used as a light absorption portion.
In addition, the spectral reflectance distribution of the reflective screen in the visible light region has a maximum reflectance within a range of ±50 nm centered on the wavelengths of red, blue, and green laser light, and the ratio PA/PB It is preferable that ≧1.16 be satisfied also in the first to fifth embodiments described above from the viewpoint of increasing the contrast of the image displayed on the reflective screen.

(Regarding the evaluation of reflective screens)
Here, the reflective screens of measurement examples 1 to 4 are prepared, and the spectral reflection in the visible light range (400 to 700 nm) at point A, which is the center of the screen (display area), and point B, which is the center of the bottom edge of the screen (display area). The rate was measured at every wavelength of 0.5 nm.

The reflective screens of Measurement Examples 1 to 4 used in the measurements had the same configuration except for the colored layer 242, and were as follows.
Screen size: 947mm long, 1674mm wide (75 inches)
Surface layer 525: Unit surface lens 5251 pitch P1 = 100 μm, lens height h1 = 15 μm, surface has fine unevenness (matte shape) Base layer 524: Made of polyethylene terephthalate resin, thickness 250 μm, transmittance 59%
Lens layer 23: Made of ultraviolet curable resin, arrangement pitch P2 of unit lenses 131 = 100 μm, angle α at the bottom edge of the screen in the center of the left-right direction of the screen is approximately 5°, and angle α is approximately 20° at the center of the screen left-right direction at the top end of the screen. Yes, the angle β is constant at 90° in the arrangement direction of the unit lenses 131 Reflective layer 522: Formed only on the lens surface 323 by aluminum evaporation During measurement, the screen in each measurement example did not have the light shielding layer 527. , instead of the light shielding layer 527, a black blackout curtain (black cloth curtain) is placed on the back side of the reflective layer.

The colored layers of the reflective screen in each measurement example are as follows.
The colored layer 242 of the reflective screen of Measurement Example 1 has a light absorption characteristic of wavelength selection, and satisfies the ratio PA/PB≧1.16.
The colored layer 242 of the reflective screen of Measurement Example 2 has a light absorption characteristic of selective wavelength and satisfies the ratio PA/PB≧1.16.
The colored layer of the reflective screen of Measurement Example 3 does not have wavelength selective light absorption characteristics and has a transmittance (total light transmittance) of 70%.
The colored layer of the reflective screen of Measurement Example 4 does not have wavelength selective light absorption characteristics and has a transmittance (total light transmittance) of 59%.
The reflective screens of Measurement Examples 1 and 2 correspond to examples of the reflective screen of the sixth embodiment, and the reflective screens of Measurement Examples 3 and 4 correspond to comparative examples.

The measurement method is as follows.
The spectral reflectance was measured using a spectrophotometer (manufactured by Shimadzu Corporation, UV-2450/MPC-2200). In the measurement, samples cut into 60 mm squares centered on points A and B of the reflective screen of each measurement example were placed in the measurement chamber of a spectrophotometer. The measured wavelength range was 400 to 700 nm, which corresponds to the visible light range, and measurements were performed every 0.5 nm as described above.

FIG. 13 is a diagram showing the measurement results of the spectral reflectance of the reflective screens of Measurement Examples 1 to 4. 13(a) shows the spectral reflectance distribution at point A, and FIG. 13(b) shows the spectral reflectance distribution at point B. In FIGS. 13(a) and 13(b), the vertical axis is reflectance [%], and the horizontal axis is wavelength [nm].
Table 1 also shows the average value PA of the reflectance for red, green, and blue laser beams (LR1, LR2, LG, LB) at points A and B, based on the measurement results in FIG. 13, and the visible light The average value PB of the reflectance for each 1 nm in the range (400 to 700 nm) is determined, and the results of determining the value of the ratio PA/PB and the results of visual evaluation of the image are shown. Regarding the results of the visual evaluation shown in Table 1, ◯ indicates that a bright and good image with high contrast was viewed, and × indicates that a dark image with low contrast was viewed.

As shown in FIG. 13, in the reflective screens of measurement examples 1 and 2, in the spectral reflectance distribution in the visible light region (400 to 700 nm), red, green, and blue laser light (LR1, LR2, LG, LB) The reflectance has a maximum value within a range of ±50 nm around the wavelength of , but such a maximum value was not observed in the reflective screens of Measurement Examples 3 and 4.
Furthermore, as shown in Table 1, in the reflective screens of Measurement Examples 1 and 2, which correspond to Examples, the ratios PA/PB were 1.19 and 1.16, respectively, at point A, and 1.19 and 1.16, respectively, at point B. 22, 1.16, which satisfies the preferred range of the ratio PA/PB.
On the other hand, in the reflective screens of measurement examples 3 and 4, the ratio PA/PB is 1.06 and 0.98, respectively, at point A, and 1.06 and 0.97, respectively, at point B. The preferred range of PA/PB is not met.

Image light was actually projected from the image source LS onto the reflective screens of measurement examples 1 to 4, and the image source at point A, which is the center of the screen, was measured in a bright room environment (illuminance 700 lx at point A). When we checked the images displayed at points A and B from a position 3 m in the side front direction and 1.5 m above the floor, we found that the measurements corresponded to the examples as shown in Table 1. With the reflective screens of Examples 1 and 2, the contrast of the image was high and a bright and good image was visible, but with the reflective screens of Measurement Examples 3 and 4, the contrast of the image was The image quality was low, the images were dark, and the clarity was poor.
Therefore, the reflective screen preferably satisfies the ratio PA/PB≧1.16, as described above.
Since the reflective screen of this embodiment satisfies the ratio PA/PB≧1.16, it is possible to suppress a decrease in contrast due to external light and display bright and good images.

On the other hand, it has been found that even if the value of this ratio PA/PB satisfies a preferable range, when a white display or a black display is performed on a reflective screen, a bias in color tone may occur in an image or the like. That is, it has been found that if the ratio PA/PB is increased in order to suppress a decrease in image contrast due to external light, the color balance in the reflected light of the reflective screen may be biased, resulting in a decrease in color reproducibility.
The chromaticity of the black color displayed on the reflective screen is determined by the reflected light of external light (light in the visible light range) that is incident on the reflective screen, and the white color displayed on the reflective screen is determined by the reflected light of the external light (light with wavelengths in the visible light range) that is incident on the reflective screen. It depends on the spectral reflectance of reflected light.

Regarding the black display on the reflective screen, the chromaticity of the achromatic color that is the reference color in the L ^* a ^* b ^* color space (CIE1976) and the chromaticity of the black display on the reflective screen (i.e., the reflection of external light) The value of ΔE ^* ab, which is the difference from the chromaticity of light), is preferably 2.4 or less (ΔE ^* ab≦2.4). When the value of the color difference ΔE ^* ab exceeds 2.4, the black display on the reflective screen will have a biased color tone, and the black (achromatic color) will be visually perceived as having other chromatic colors added to it. Color reproducibility decreases.
Regarding the white display of the reflective screen, when ΔR is the difference between the maximum value and minimum value of reflectance at the wavelength of red, blue, and green laser light (LR1, LR2, LG, LB), ΔR≦ It is preferable to satisfy 2.6%. When ΔR satisfies this range, the difference in the reflectance of each laser beam becomes small, the bias in color tone in white display can be reduced, and color reproducibility can be improved.

Here, the reflective screen of Measurement Example 5 was further prepared, and the reflectance distribution in the visible light range (400 to 700 nm) at point A was measured in the same manner as the reflective screens of Measurement Examples 1 to 4 described above. In the reflective screen of Measurement Example 5, each layer other than the colored layer 242 is the same as the reflective screens of other measurement examples, and the ratio PA/PB is 1.16, which satisfies the preferable range of the ratio PA/PB. ing.

Then, ΔE ^* ab of black display at point A was calculated for each of the reflective screens of Measurement Examples 1 to 5. First, the chromaticity of the standard white plate was measured as a reference using the spectrophotometer described above, and the reflectance spectroscopy of the reflective screen sample (60 mm square sample centered on point A) for each measurement example was performed. The spectrum was obtained by actual measurement. The color difference ΔE ^* ab for black display was obtained by calculating the chromaticity values L ^* , a ^* , b ^* for a standard D65 light source and calculating from these values.
In addition, for the reflective screens of measurement examples 1 to 5, the difference ΔR between the maximum and minimum reflectance at the wavelengths of red, green, and blue laser light (LR1, LR2, LG, LB) at point A is calculated. Calculated.
Furthermore, regarding the reflective screen of each measurement example, the color tone at point A in a bright room environment (illuminance 700 lx at point A) without projection of image light (black display state), and in a bright room environment. The color tone at point A was visually evaluated in a state in which image light forming a white screen was projected from the image source LS at (illuminance at point A: 700 lx) (white display state). The visual evaluation was performed at a position 3 m in the front direction of the image source side of point A, which is the center of the screen, and at a height of 1.5 m from the floor surface.

FIG. 14 is a diagram showing the measurement results of the spectral reflectance at point A of the reflective screen in Measurement Examples 1 to 5, and the vertical and horizontal axes are the same as in FIG. 13. The graph shown in FIG. 14 corresponds to the graph of FIG. 13(a) described above, with the measurement results of the reflective screen of measurement example 5 added.

Table 2 shows the color difference ΔE ^* ab between the black display at point A and the reference achromatic color on the reflective screen of each measurement example, and the maximum and minimum values of the reflectance of each laser beam at point A. The difference ΔR and the results of visual evaluation are shown. Regarding the results of the visual evaluation shown in Table 2, ○ indicates that there was no color bias and was visually recognized as an achromatic color, and × indicates that a color bias was visible and it was not visually recognized as an achromatic color. .
As shown in Table 2, the reflective screen of Measurement Example 5 has PA/PB=1.16, which satisfies the preferred range of the ratio PA/PB, but ΔE ^* ab in black display is larger than 2.4. , outside the preferred range. On the other hand, for the reflective screens of Measurement Examples 1 to 4, ΔE ^* ab in black display was 2.4, 1.9, 1.8, and 2.1, respectively, and ΔE ^* ab≦2.4. is met.
Furthermore, in the visual evaluation of black display, the reflective screens in Measurement Examples 1 to 4 have no color bias and are visually perceived as achromatic, but the reflective screen in Measurement Example 5 shows a color bias. It was visually recognized as a chromatic color.

Regarding white display, as shown in Table 2, for the reflective screens of measurement examples 1, 2, and 5, ΔR is 0.7% and 2.5%, respectively, and ΔR≦2.6%, and ΔR satisfies the preferred range. On the other hand, the reflective screens of Measurement Examples 3 and 4 have ΔR of 3.2% and 4.6%, which are larger than 2.6% and do not satisfy the preferable range of ΔR.
In addition, in the visual evaluation of white display, the reflective screens of measurement examples 1, 2, and 5 have no bias in color tone and are visually recognized as achromatic colors, but the reflective screens of measurement examples 3 and 4 show that the color tone is not biased. There was a bias in the colors, and they were visually recognized as chromatic colors.

From the above, the reflective screens of Measurement Examples 1 and 2 display good achromatic colors with no color bias in black and white displays, but the reflective screens of Measurement Examples 3 and 4 display good achromatic colors. It can be seen that a color bias occurs in the display, and in measurement example 5, a color bias occurs in the black display.

As described above, in the reflective screen of this embodiment, the color difference ΔE ^* ab between the chromaticity of the displayed black display and the chromaticity of the achromatic color serving as the reference color satisfies ΔE ^* ab≦2.4. , there is no bias in the color tone of the black display, and a good image can be displayed. In addition, in the reflective screen of this embodiment, the difference ΔR between the maximum value and the minimum reflectance of each laser beam in white display satisfies ΔR≦2.6%, so the white display also has a different color tone. A good image can be displayed without any bias.

[Other embodiments]
Although the specific configuration suitable for implementing the present invention has been described above in detail, the configuration of the above-described embodiment can be variously changed without departing from the spirit of the present invention, and furthermore, Various combinations are possible.

(1) In each of the above-mentioned embodiments, the case where one member of the reflective screen is used as a light absorption portion or the case where a light absorption layer is arranged at one place between the members of the reflective screen is shown, but the present invention is not limited to this. Instead, a plurality of members of the reflective screen may be used as light absorbing parts, and the light absorbing parts may be arranged at a plurality of locations between the members of the reflective screen. Further, the members of the reflective screen may be used as light absorbing portions, and a light absorbing layer may be provided between the members of the reflective screen.

(2) In the above-described fourth embodiment, an example was shown in which the reflective screen 320 includes the light absorption layer 326 having a multilayer structure in which a plurality of absorption layers (326a to 326d) are laminated, but the present invention is not limited to this. Instead, one layer of light absorption layer 326 may be formed by mixing materials A to D shown in FIG. 4 with a resin serving as a base material.

(3) In the fifth embodiment described above, the reflective screen 420 may omit the black area BL of the light absorption layer 426. Thereby, the method for manufacturing the light absorption layer 426 can be simplified and manufacturing efficiency can be improved.

(4) In the fifth embodiment described above, an example is shown in which the light absorption layer 426 is painted separately into the red region R, the green region G, and the blue region B. However, the present invention is not limited to this. An ink may be prepared by mixing a material having wavelength selectivity contained in the region, and the ink may be applied by a spray method or the like so that it is formed closer to the image source than the reflective layer 22. For example, when forming the light absorption layer 426 between the reflective layer 22 and the lens layer 23, the above-mentioned ink is applied to the back surface of the lens layer 23 by a spray method, and after drying, the formed light absorption layer 426 is A reflective layer 22 may be formed on the back surface.

1 Video display system 20, 120, 320, 420, 520 Reflective screen 22, 522 Reflective layer 23, 123 Lens layer 24, 124, 524 Base layer 241 Light diffusion layer 242 Colored layer 25, 225, 525 Surface layer 326, 426 Light absorption layer 30 Support plate 40 Bonding layer 231 Unit lens 232 Lens surface 233 Non-lens surface

Claims (5)

A reflective screen that allows viewing by reflecting red, green, and blue laser beams projected from an image source, the screen comprising:
a base material layer;
a lens layer in which a Fresnel lens shape is formed on the back side of the base layer that is opposite to the image source side;
and a reflective layer provided on the back side of the lens layer,
A light absorption section having wavelength selectivity is provided closer to the image source than the reflective layer,
the light absorption section is formed of the lens layer containing a material having wavelength selectivity;
A reflective screen featuring. The reflective screen according to claim 1 ,
The light absorption part is
Containing a material that has multiple types of wavelength selectivity and has a light absorption band in a wavelength band that does not include the wavelengths of the red, green, and blue laser beams;
A reflective screen featuring. The reflective screen according to claim 1,
When the spectral reflectance of the reflective screen is measured, the reflectance has a maximum value within a range of ±50 nm centered on the wavelengths of the red, green, and blue laser beams;
A reflective screen featuring. The reflective screen according to claim 3 ,
The light absorption part is
When the average value of the reflectance at the wavelengths of the red, green, and blue laser beams is PA, the average value of the reflectance at the wavelength of light in the visible light region is PB, and the ratio of these is PA/PB,
PA/PB≧1.16
to satisfy,
A reflective screen featuring. The reflective screen according to any one of claims 1 to 4 ,
an image source that irradiates the reflective screen with image light;
A video display system equipped with

Images