JP2017058471A - Transmissive screen and display unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmissive screen that has good anisotropy with respect to a viewing angle and excellent visibility, and a display unit including such a transmissive screen.SOLUTION: A transmissive screen 16 comprises: an anisotropic light diffusion layer 30 that anisotropically diffuses incident light; an isotropic light diffusion layer 31 that is arranged closer to a light emission side than the anisotropic light diffusion layer 30 and isotropically diffuses incident light; a colored layer 32 that includes a colorant; and a light control layer 33 that is arranged closer to the light emission side than the isotropic light diffusion layer 31. The light control layer 33 includes a plurality of unit light transmission parts 37 and a plurality of unit light absorption parts 38 that are arranged between the plurality of unit light transmission parts 37. The transmissive screen 16 having such a structure transmits video light projected from a light incident side through the light emission side.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a transmissive screen having a colored layer and a display device including such a transmissive screen.

  In a rear projection type display device that projects and displays video light from the back side of the screen, a transmissive screen that transmits the projected video light and displays an image is used.

  For example, Patent Document 1 discloses a display device including a transmissive screen. The transmissive screen includes an ionizing radiation curable resin layer having a plurality of unit light absorbing portions and a plurality of unit light transmitting portions, and an intermediate layer that is disposed on the light output side of the ionizing radiation curable resin layer and includes a diffusing component. Is provided.

JP 2012-32513 A

  The transmission screen can be applied to various fields. For example, the transmission screen can be suitably used as an in-vehicle transmission screen having a colored layer (also called a tint layer) that suppresses transmission and reflection of light.

  The in-vehicle transmission type screen is preferably limited in view angle in the vertical direction to prevent reflection on the windshield, while it is horizontal to ensure visibility from the driver's seat or passenger seat. It is preferable that the viewing angle in the direction is sufficiently wide. Thus, the in-vehicle transmission screen preferably has anisotropy with respect to the viewing angle.

  Therefore, while appropriately limiting the viewing angle in a specific direction (for example, the vertical direction), the viewing angle in the other direction (for example, the horizontal direction) can be secured sufficiently, while providing excellent visibility. A proposal of a transmissive screen that can be used is desired. In particular, in order to realize an anisotropic viewing angle, the layer structure of a transmissive screen tends to be complicated, and a transmissive screen is formed by combining elements having various optical characteristics with respect to diffusion, refraction, reflection, and the like. Composed. For this reason, light incident on the transmissive screen follows a complicated path and is emitted from the transmissive screen, and a deteriorated image such as a multiple image (double image) may be output from the transmissive screen. Therefore, it is desired to propose a transmission screen that can effectively prevent the generation of multiple images and the like and can provide an image with excellent visibility.

  The present invention has been made in view of the above circumstances, and provides a transmission screen having good anisotropy with respect to a viewing angle and excellent visibility, and a technique related to such a transmission screen. With the goal.

  One aspect of the present invention is a transmission screen that transmits image light projected from the light incident side to the light output side, and includes an anisotropic light diffusion layer that anisotropically diffuses incident light, and an anisotropic light diffusion layer. Is disposed on the light exit side, isotropic light diffusion layer for isotropically diffusing incident light, a colored layer containing a coloring material, and disposed on the light output side from the isotropic light diffusion layer, and a plurality of unit light transmission portions, The present invention relates to a transmissive screen including a light control layer having a plurality of unit light absorbing portions disposed between the plurality of unit light transmitting portions.

  According to the present invention, the viewing angle in one specific direction is appropriately limited by the light control layer, and the viewing angle in the other direction can be appropriately ensured by the anisotropic light diffusion layer and the isotropic light diffusion layer. A transmissive screen having visibility can be realized.

  The colored layer may be disposed between the anisotropic light diffusion layer and the light control layer.

  The colored layer may be in contact with the isotropic light diffusing layer on one of the light incident side and the light emitting side of the isotropic light diffusing layer.

  According to this aspect, the colored layer and the isotropic light diffusing layer can be easily formed. For example, the colored layer and the isotropic light diffusing layer can be accurately and easily formed by a two-layer extrusion molding method.

  The total thickness of the isotropic light diffusing layer and the colored layer on the light exiting side from the light entering side may be smaller than 500 μm.

  According to this aspect, it is possible to effectively prevent the generation of multiple images in the observation image.

  The thickness of the colored layer may be not less than 0.060 mm and not more than 0.535 mm.

  According to this aspect, it is possible to effectively prevent the generation of multiple images in the observation image.

  The anisotropic light diffusion layer has a plurality of unit light diffusion portions, and each of the plurality of unit light diffusion portions may extend in a direction non-parallel to the direction in which each of the plurality of unit light absorption portions extends. .

  According to this aspect, the viewing angle having anisotropy can be realized with high accuracy.

  The transmission screen has a curved shape and may have a curved screen surface.

  According to this aspect, it is possible to realize a transmission screen having good design properties.

  The transmission screen may further include a rigid layer.

  According to this aspect, it is possible to realize a transmission screen having excellent rigidity.

  Each of the plurality of unit light absorption units and each of the plurality of unit light transmission units extends in the left-right direction in the usage state of the transmission type screen, and the plurality of unit light absorption units and the plurality of unit light transmission units are transmissive You may arrange | position along with the up-down direction which is perpendicular | vertical to the left-right direction in the use condition of a screen.

  According to this aspect, it is possible to realize a transmissive screen with a wide viewing angle in the left-right direction while limiting the viewing angle in the up-down direction in the usage state of the transmissive screen.

  Another aspect of the present invention relates to a display device including the above-described transmission screen and an image light source that is disposed on the back side of the transmission screen and projects image light onto the transmission screen.

  The display device may further include a mirror unit that reflects the image light from the image light source and projects the image light onto the transmission screen.

  According to this aspect, the degree of freedom regarding the arrangement of the image light source and the transmissive screen is high.

  According to the present invention, it is possible to provide a transmissive screen including a colored layer having good anisotropy with respect to a viewing angle and having excellent visibility, and a display device including such a transmissive screen.

FIG. 1 is a diagram schematically showing a display device, and is a diagram showing an example of an arrangement relationship between an observer and a display device (video light source and transmissive screen). FIG. 2 is a perspective view schematically showing an image light source and a transmissive screen. FIG. 3 is a partial perspective view showing the layer structure of the transmission screen according to the first embodiment. FIG. 4 is a partial perspective view showing the layer structure of the transmission screen in which the light control layer is removed from the transmission screen shown in FIG. FIG. 5 is a partial perspective view showing the layer structure of the transmission screen according to the second embodiment, and shows the transmission screen having a relatively thin colored layer. FIG. 6 is a partial perspective view showing a layer configuration of a transmission screen having a relatively thick colored layer, and shows a transmission screen having substantially the same rigidity as the transmission screen shown in FIG. FIG. 7 shows an observation example of image light projected on the transmission screen of FIG. FIG. 8 shows an example of observation of image light projected on the transmission screen of FIG. FIG. 9 is a conceptual diagram showing a partially enlarged cross section of the isotropic light diffusing layer, the colored layer, and the light control layer, and explaining the mechanism of generating multiple images. FIG. 10 is a partially enlarged cross-sectional view of the unit light absorbing portion of the light control layer, and (a) to (c) are diagrams for explaining the angular relationship related to the unit light absorbing portion. FIG. 11 is a conceptual diagram illustrating partial enlarged cross sections of the isotropic light diffusion layer, the colored layer, and the light control layer, and illustrating an example of the relationship between the interval between the real image light and the ghost image light and the thickness of the colored layer. FIG. 12 is a diagram schematically showing a modification of the display device. FIG. 13 is a diagram schematically showing another modification of the display device.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  In the drawings attached to the present specification, for convenience of illustration and understanding, the scale and size ratio of each element are exaggerated and changed from the actual scale and size ratio. Further, in the present specification, the terms “layer”, “plate”, “sheet” and “film” are not distinguished from each other based only on the difference in names. For example, the term “layer” is a concept including a member that can be called a plate, a sheet, or a film. In addition, the “sheet surface (plate surface or film surface)” is a sheet-like member (plate-like) that is an object when the target sheet-like (plate-like or film-like) member is viewed as a whole and globally. It refers to the surface that matches the planar direction of the member or film-like member. In addition, the terms used in this specification, the geometric conditions, and the terms that specify the degree thereof (for example, terms such as “parallel”, “orthogonal” and “same”, length and angle values, etc.) are strictly Without being bound by any meaning, it is interpreted as meaning a range where substantially equivalent and similar functions can be expected.

  FIG. 1 is a diagram schematically showing the display device 12, and is a diagram showing an example of an arrangement relationship between the observer 10 and the display device 12 (the image light source 14 and the transmissive screen 16).

  The display device 12 of this example is configured as a so-called rear projection display device. The display device 12 transmits the image light L1 projected from the light incident side to the light output side, and the rear surface (light incident surface) of the transmission screen 16. And a video light source 14 such as a projector that projects the video light L1 onto the transmissive screen 16. The “light incident side” relating to the transmissive screen 16 is the image light source 14 side, and the “light exit side” relating to the transmissive screen 16 is the observer 10 side.

  In addition, the specific aspect of the image light L1 mentioned here is not specifically limited, The image light L1 can contain the whole light regardless of a specific kind and content. Typically, the image light L1 can be composed of light representing a specific pattern or information, but light having any other form (for example, light representing an irregular pattern or light that does not represent any specific information) ) May constitute the image light L1.

  The image light source 14 of this example irradiates the entire area of the light incident surface 18 of the transmission screen 16 with the image light L1 as a divergent light beam (expanded projected light beam) whose irradiation region gradually expands. Such a video light source 14 is not particularly limited. For example, a method using a cathode ray tube (CRT), a method using liquid crystal, a method using a digital micromirror device (DMD: Digital Micromirror Device), or the like. Can be used as the image light source 14.

  The transmissive screen 16 has a light incident surface 18 positioned on the light incident side and a light output surface 20 positioned on the light output side, and transmits the image light L1 irradiated to the light incident surface 18 from the image light source 14 to emit light. 20 is emitted to the light output side (observer 10 side). The observer 10 can visually recognize the image by observing the image light L1 emitted from the light exit surface 20 of the transmissive screen 16.

  FIG. 2 is a perspective view schematically showing the image light source 14 and the transmissive screen 16. The transmission screen 16 of this example has a curved shape such that the light incident surface 18 is convex as a whole and the light output surface 20 is concave as a whole, and has a curved screen surface (light output surface 20). In the example of FIG. 2, the transmissive screen 16 is curved in a curved shape so that each of the light incident surface 18 and the light emitting surface 20 forms a three-dimensional curved surface. Here, being curved in the shape of a curved surface forming a three-dimensional curved surface means that it is partially or entirely bent around a plurality of axes inclined with respect to each other. In this example, the transmission screen 16 having a substantially rectangular shape is curved in a direction d1 that is substantially parallel to the vertical direction and centered on the first axis A1 that is located on the light output side of the transmission screen 16, and in the horizontal direction. Parallel to the tangential plane of the transmissive screen 16 at the center position Pa of the transmissive screen 16, and curved in a direction d2 centered on the second axis A2 located on the light output side of the transmissive screen 16. Yes. As a result, the transmissive screen 16 is curved so as to form a three-dimensional curved surface that is convex toward the image light source 14 as a whole, and the light incident surface 18 protrudes most toward the image light source 14 at the center position Pa of the transmissive screen 16. It will be in the state. The transmission screen 16 of this example has a multilayer structure in which a plurality of layers are stacked as will be described later, and each layer is curved so as to form a three-dimensional curved surface.

  The transmissive screen 16 can include a deflection optical plate (not shown) and a laminated plate (see FIG. 3) described later disposed on the light output side of the deflection optical plate. In this case, each layer included in the deflecting optical plate and the laminated plate may be curved to form a substantially similar three-dimensional curved surface. The deflection optical plate may not be provided. In this case, the image light L1 from the image light source 14 is directly incident on the laminated plate. Therefore, when the transmissive screen 16 is constituted by a deflecting optical plate and a laminated plate, the light incident surface 18 is constituted by the deflecting optical plate, and a laminated plate (in the embodiment described later, a light control layer 33 (see FIG. 3) or a rigid layer). 34 (see FIG. 5)), the light exit surface 20 is configured. When the transmissive screen 16 includes only the laminated plate without including the deflecting optical plate, both the light incident surface 18 and the light emitting surface 20 are configured by the laminated plate.

  The deflecting optical plate may have, for example, a light incident side transparent base material layer and a Fresnel lens layer that are sequentially arranged from the light incident side toward the light output side. The light incident side transparent base material layer is a layer made of a transparent resin such as acrylic resin, styrene resin, polyester resin, polycarbonate resin, or acrylic-styrene copolymer resin, and can prevent deformation of the Fresnel lens layer. Thus, it functions as a support base material that supports the Fresnel lens layer. The Fresnel lens layer has a plurality of unit lenses that form a Fresnel lens. The Fresnel lens formed by the unit lens has a function of deflecting the traveling direction of the image light L1 projected from the image light source 14 onto the transmission screen 16 as a divergent light beam. Specifically, the Fresnel lens converts image light incident as a divergent light beam into a parallel light beam that travels from the light incident side toward the light output side. In this way, by collimating the image light once using the Fresnel lens, in-plane variation in brightness of an image observed by the observer 10, particularly an image observed from an oblique direction by the observer 10, is effective. Can be relaxed. This Fresnel lens may be configured as a circular Fresnel lens or a linear Fresnel lens.

  Next, a specific embodiment of the transmission screen 16 (particularly the above-described laminated plate) will be described.

<First Embodiment>
FIG. 3 is a partial perspective view showing the layer structure of the transmission screen 16 according to the first embodiment. In FIG. 3, the right side of the paper corresponds to the incident side, the left side corresponds to the outgoing side, and the image light L1 from the image light source 14 (see FIGS. 1 and 2) is directed from the right side to the left side in FIG. (See arrow “X” in FIG. 3). In FIG. 3, the direction connecting the upper side and the lower side toward the paper surface (see arrow “Z” in FIG. 3) corresponds to the “vertical direction in the assumed use state of the transmissive screen 16”, and toward the paper surface. The direction connecting the back side and the near side (see arrow “Y” in FIG. 3) corresponds to the “left-right direction in the assumed use state of the transmissive screen 16”, and this “vertical direction (arrow“ Z ”in FIG. 3). “See” is perpendicular to “left-right direction (see arrow“ Y ”in FIG. 3)”. For ease of understanding, FIG. 3 shows a part of the transmissive screen 16 drawn in a flat plate shape. However, as described above, each layer of the transmissive screen 16 of this example is actually shown in FIG. It is curved.

  The transmissive screen 16 according to the present embodiment includes an anisotropic light diffusing layer 30, an isotropic light diffusing layer 31, a colored layer 32, and a light control layer 33 (LAF: Lover Array Film) arranged in order from the light incident side to the light emitting side. ).

  The anisotropic light diffusion layer 30 is a layer that anisotropically diffuses light (image light L1) incident from the image light source 14 (see FIGS. 1 and 2), and in this example, a plurality of units that reflect incident light. A light diffusion unit 40 is included. Each of the plurality of unit light diffusion portions 40 extends linearly in the vertical direction (see the arrow “Z” in FIG. 3) toward the plane of the paper in FIG. Each of the absorbing portions 38 "extends in a direction non-parallel to the extending direction. The unit light diffusing unit 40 of this example diffuses incident light (video light L1) anisotropically mainly in the left-right direction of the transmission screen 16 (see arrow “Y” in FIG. 3). The diffusion method by the unit light diffusing unit 40 is not particularly limited. For example, the unit light diffusing unit 40 may be caused by a difference in refractive index between the unit light diffusing unit 40 and members around the unit light diffusing unit 40 or the unit light diffusing unit 40. Due to its own reflectivity, incident light can be diffused anisotropically.

  In addition, the member and shape which comprise the unit light-diffusion part 40 are not specifically limited. Each unit light diffusing section 40 can be composed of, for example, an ionizing radiation curable resin containing a light absorbing material or the like, and emits light from the left-right direction of the transmission screen 16 (see arrow “Y” in FIG. 3) and from the light incident side. It may have a wedge shape (for example, a triangular shape or a trapezoidal shape) in a cross section along a direction toward the side (see an arrow “X” in FIG. 3). Each unit light diffusion section 40 shown in FIG. 3 is arranged in the left-right direction of the transmission screen 16 (see arrow “Y” in FIG. 3) and in the direction from the light incident side toward the light emission side (see arrow “X” in FIG. 3). In the cross section along, the size of the transmissive screen 16 in the left-right direction (see arrow “Y” in FIG. 3) is configured to gradually increase from the light incident side toward the light outgoing side.

  The isotropic light diffusion layer 31 is disposed on the light output side with respect to the anisotropic light diffusion layer 30 and diffuses incident light (video light L1) isotropically. The configuration of the isotropic light diffusion layer 31 is not particularly limited, but typically, the isotropic light diffusion layer 31 includes a base portion made of a transparent resin and a diffusion component dispersed in the base portion. Incident light is diffused isotropically due to the difference in refractive index between the components or due to the reflectivity of the diffusing component itself.

  Such an isotropic light diffusion layer 31 can be produced by, for example, forming a thermoplastic resin containing a large number of dispersed particulate diffusion components into a plate shape by extrusion. As the transparent resin constituting the base portion, for example, methyl methacrylate butadiene styrene copolymer (MBS), acrylic resin, polycarbonate resin, or the like can be used. Examples of the particulate diffusion component include inorganic fine particles such as barium sulfate fine particles, glass fine particles, aluminum hydroxide fine particles, calcium carbonate fine particles, silica (silicon dioxide) fine particles, titanium oxide fine particles, melamine beads, acrylic beads, acrylic- Although organic fine particles such as styrene beads, polycarbonate beads, polyethylene beads, polystyrene beads, polyvinyl chloride beads, or silicone beads can be used, it is preferable to use organic fine particles from the viewpoint of transparency. Alternatively, the diffusing component may be a bubble. The diameter of the diffusion component is not particularly limited, but a diffusion component having a diameter of about 1 to 15 μm is usually used in the isotropic light diffusion layer 31.

  The colored layer 32 is disposed between the anisotropic light diffusion layer 30 and the light control layer 33 (between the isotropic light diffusion layer 31 and the light control layer 33 in the present embodiment), and is incident on the light incident side of the isotropic light diffusion layer 31. And the isotropic light diffusion layer 31 in contact with either one of the light exit side and the light exit side (the light exit side in this embodiment).

  The colored layer 32 is typically composed of a resin composition containing a transparent resin and a coloring material. The colorant contained in the colored layer 32 is not particularly limited as long as it absorbs light. For example, a black dye, a black pigment, or carbon black can be suitably used as the colorant of the colored layer 32. The color of the material is not particularly limited. The transparent resin contained in the colored layer 32 is not particularly limited. For example, methyl methacrylate butadiene styrene copolymer (MBS), acrylic resin, methacrylate-styrene resin, acrylate-styrene resin, polypropylene resin, polyethylene terephthalate resin. Polyvinyl chloride resin, polycarbonate resin, or the like can be suitably used as the transparent resin for the colored layer 32. Among these, a transparent resin having a relatively high refractive index, for example, a transparent resin having a refractive index of about 1.55 to 1.60 is preferable as the transparent resin of the colored layer 32, for example, a polycarbonate resin (refractive index n = 1.60). Etc. can be preferably used as the transparent resin of the colored layer 32.

  The thickness of the isotropic light diffusing layer 31 and the colored layer 32 from the incident side to the outgoing side (see arrow “X” in FIG. 3) prevents multiple images (double images) in the observation image of the video light L1, as will be described later. From the viewpoint of obtaining a clear and clear observation image, it is preferably as small as possible. That is, when the light control layer 33 is disposed on the light exit side (light exit surface 20 side), multiple images are likely to occur if the distance between the light diffusion layer (particularly the isotropic light diffusion layer 31) and the light control layer 33 is large. For this reason, it is preferable to reduce the total thickness of the isotropic light diffusion layer 31 and the colored layer 32.

  As shown in FIGS. 5 to 8 described later, the present inventor is a transmission type screen 16 in which an isotropic light diffusion layer 31 and a colored layer 32 are formed by a two-layer extrusion molding method, and the film thickness of the colored layer 32 is as follows. A plurality of types of transmission screens 16 having different sizes in the direction of the arrow “X” in FIG. 3 were produced, and the observation images provided via the transmission screens 16 were evaluated. In this evaluation, as the colored layer 32 is thicker and the distance between the isotropic light diffusion layer 31 and the light control layer 33 is larger, multiple images (double images) are more conspicuous in the observed image, and the colored layer 32 is thinner and isotropic light diffusion layer. It was confirmed that the smaller the distance between the light source 31 and the light control layer 33, the less the multiple image becomes conspicuous in the observation image, and the better the visibility of the image. For example, the present inventor has confirmed through experiments that the multiple images can be effectively prevented when the total thickness of the isotropic light diffusion layer 31 and the colored layer 32 is smaller than 500 μm.

  The light control layer 33 is disposed on the light output side with respect to the isotropic light diffusion layer 31 and the colored layer 32, and is provided with a transparent sheet-like base portion 36 and a plurality of unit light transmissions provided on the base portion 36 and having light transmittance. And a plurality of unit light absorbing portions 38 provided on the base portion 36 and having light absorption properties. The unit light transmitting portions 37 and the unit light absorbing portions 38 are alternately arranged on the base portion 36, and the plurality of unit light absorbing portions 38 are respectively disposed between the plurality of unit light transmitting portions 37. That is, each of the plurality of unit light absorbing portions 38 and each of the plurality of unit light transmitting portions 37 extends linearly in the left-right direction (see arrow “Y” in FIG. 3) in the usage state of the transmissive screen 16. The plurality of unit light absorbing portions 38 and the plurality of unit light transmitting portions 37 are arranged side by side in the vertical direction (see arrow “Z” in FIG. 3) when the transmission screen 16 is in use.

  Therefore, in this embodiment, “the direction in which each unit light absorbing portion 38 of the light control layer 33 extends” and “the direction in which each unit light transmitting portion 37 of the light control layer 33 extends” are parallel to each other. “The direction in which the plurality of unit light absorbing portions 38 and the plurality of unit light transmitting portions 37 are arranged (arrangement direction)” is orthogonal. Further, “the direction in which each unit light absorbing portion 38 and each unit light transmitting portion 37 of the light control layer 33 extend” and “the direction in which each unit light diffusion portion 40 of the anisotropic light diffusion layer 30 extends” are mutually connected. Non-parallel and orthogonal to each other.

  As shown in FIG. 3, the unit light transmitting portions 37 of the present embodiment are arranged in the direction (see arrow “Z” in FIG. 3) and the thickness direction of the light control layer 33 (see arrow “X” in FIG. 3). And a cross-sectional shape of a trapezoidal shape (so-called isosceles trapezoidal shape) in the cross-section along both, and a constant cross-sectional shape along the longitudinal direction (see arrow “Y” in FIG. 3). Therefore, each unit light transmitting portion 37 is arranged so that the lower base of each trapezoidal cross section of each unit light transmitting portion 37 is located on the light output side and the upper base shorter than the lower bottom is located on the light incident side.

  As an example, the unit light transmission part 37 can be produced by forming an ionizing radiation curable resin on a base material sheet constituting a part of the base part 36. Examples of the ionizing radiation curable resin include resins such as epoxy acrylate that are cured by irradiation with ionizing radiation such as an electron beam or ultraviolet rays. As a manufacturing method of the light control layer 33 including such a unit light transmission part 37, for example, a method disclosed in International Publication No. 2006/090784 can be used.

  On the other hand, each unit light absorbing portion 38 is formed in a region between two unit light transmitting portions 37 adjacent to each other along the arrangement direction (see arrow “Z” in FIG. 3). Adjacent and may have a wedge shape (for example, a triangular shape or a trapezoidal shape) in a cross section along both the arrangement direction (see arrow “Z” in FIG. 3) and the thickness direction (see arrow “X” in FIG. 3). That is, in the example shown in FIG. 3, each unit light absorbing portion 38 is formed in the vertical direction of the transmission screen 16 (see arrow “Z” in FIG. 3) and in the thickness direction of the light control layer 33 (see arrow “X” in FIG. 3). In the cross-section along, the size of the transmissive screen 16 in the vertical direction (see arrow “Z” in FIG. 3) is gradually reduced from the light incident side toward the light outgoing side.

  As shown in FIG. 3, the unit light absorbing portions 38 of the present embodiment are arranged in the direction (see arrow “Z” in FIG. 3) and the thickness direction of the light control layer 33 (see arrow “X” in FIG. 3). And a cross-sectional shape of a trapezoidal shape (so-called isosceles trapezoidal shape) in the cross-section along both, and a constant cross-sectional shape along the longitudinal direction (see arrow “Y” in FIG. 3). Accordingly, each unit light absorbing portion 38 is arranged so that the lower base of the trapezoidal cross section of each unit light absorbing portion 38 is located on the light incident side, and the upper base shorter than the lower base is located on the light outgoing side. The light (image light L1) traveling from the colored layer 32 toward each unit light absorbing portion 38 having such a shape is reflected or absorbed by the unit light absorbing portion 38. In particular, each unit light absorber 38 extends linearly in the left-right direction (see arrow “Y” in FIG. 3) when the transmissive screen 16 is in use, so that the vertical direction (arrow “Z” in FIG. 3). While the range in which light can travel to (see FIG. 3) is limited, the range in which light can travel in the left-right direction (see arrow “Y” in FIG. 3) of the transmission screen 16 is not limited. Therefore, the plurality of unit light absorbers 38 limit the viewing angle in the up and down direction (see arrow “Z” in FIG. 3) in the usage state of the transmissive screen 16, while referring to the other direction (see arrow “Y” in FIG. 3). ) Has a function that does not limit the viewing angle.

  As an example, the unit light absorbing portion 38 is formed by applying an ionizing radiation curable resin containing a light absorbing material or the like onto the plurality of unit light transmitting portions 37 formed on the base sheet, and by means of means such as a squeegee. The ionizing radiation curable resin is filled between the unit light transmitting portions 37, and thereafter the ionizing radiation curable resin is cured by irradiating with ionizing radiation. The ionizing radiation curable resin itself containing a light absorbing material or the like can be a transparent resin. As a method for producing the unit light absorbing portion 38 on the base portion 36, for example, a method disclosed in International Publication No. 2006/090784 can be used.

  The “ionizing radiation curable resin containing a light absorbing material” constituting the unit light absorbing portion 38 is preferably a resin material having a refractive index smaller than the refractive index of the transparent resin constituting the unit light transmitting portion 37. . In this case, the video light L1 that has traveled through the unit light transmitting portion 37 and entered the interface between the unit light transmitting portion 37 and the unit light absorbing portion 38 is likely to be reflected at this interface. The resin material used as the ionizing radiation curable resin constituting the unit light absorbing portion 38 is not particularly limited. For example, an acrylate resin such as urethane acrylate or epoxy acrylate that is cured by ionizing radiation such as an electron beam or ultraviolet rays is used. Can be used. Examples of the light absorbing material include metal salts such as carbon black, graphite and black iron oxide, pigments, dyes, and resin particles colored with pigments or dyes.

  FIG. 4 is a partial perspective view showing the layer structure of the transmission screen 16 in which the light control layer 33 is removed from the transmission screen 16 shown in FIG. The directional relationship of the transmissive screen 16 in FIG. 4 is the same as the directional relationship of the transmissive screen 16 shown in FIG. 3 (see arrows “X”, “Y”, and “Z” in FIG. 4). For ease of understanding, FIG. 4 shows a part of the flat transmission screen 16, but in reality, each layer of the transmission screen 16 is curved as described above.

  As described above, in the transmissive screen 16 shown in FIG. 3, the light control layer 33 (unit light transmitting portion 37 and unit light absorbing portion 38) causes light to travel in the vertical direction (see arrow “Z” in FIG. 3). Limited. Therefore, as compared with the transmission screen 16 of FIG. 4 that does not have the light control layer 33, the transmission screen 16 of FIG. 3 having the light control layer 33 has a viewing angle in the vertical direction (see arrow “Z” in FIG. 3). The image light L1 can be emitted in a limited state.

  In the left-right direction of the transmission screen 16 (see arrow “Y” in FIG. 3), the image light L 1 is diffused by the anisotropic light diffusion layer 30 and the isotropic light diffusion layer 31, while the image light L 1 is diffused by the light control layer 33. The progression of L1 is not inhibited. Therefore, the transmissive screen 16 in FIG. 3 has a limited viewing angle in the vertical direction (see arrow “Z” in FIG. 3), but has a wide field of view in the left-right direction (see arrow “Y” in FIG. 3). A corner can be realized and an image with excellent visibility can be provided to the observer 10.

  Therefore, by applying the transmissive screen 16 shown in FIG. 3 to the in-vehicle transmissive screen, the viewing angle in the vertical direction (the above-described vertical direction (see the arrow “Z” in FIG. 3)) is limited to the windshield. To ensure good visibility from the driver's or passenger's seat by ensuring a wide viewing angle in the horizontal direction (see the left and right direction (see arrow “Y” in FIG. 3) above) while effectively preventing reflection. Can do.

Second Embodiment
FIG. 5 is a partial perspective view showing the layer structure of the transmission screen 16 according to the second embodiment, and shows the transmission screen 16 having a relatively thin colored layer 32. 6 is a partial perspective view showing a layer structure of the transmission screen 16 having a relatively thick colored layer 32, and shows the transmission screen 16 having substantially the same rigidity as the transmission screen 16 shown in FIG.

  In the transmission type screen 16 shown in FIG. 5, the isotropic light diffusion layer 31 and the colored layer 32 are formed so that the total thickness of the isotropic light diffusion layer 31 and the colored layer 32 (especially the thickness of the colored layer 32) becomes relatively small. On the other hand, a transparent rigid layer 34 is provided on the light output side of the light control layer 33. On the other hand, in the transmissive screen 16 shown in FIG. 6, the rigid layer 34 is not provided, and by increasing the thickness of the colored layer 32, the same rigidity as that of the transmissive screen 16 of FIG. ing. The rigid layer 34 shown in FIG. 5 is provided on the light output side of the light control layer 33. However, the arrangement position of the rigid layer 34 is not particularly limited, and the rigid layer 34 is arranged at an arbitrary position of the transmissive screen 16. Is possible.

  The thickness of the colored layer 32 can be changed by any method. For example, when forming the isotropic light diffusing layer 31 and the colored layer 32 by a two-layer extrusion molding method, the desired thickness can be changed by adjusting the screw rotation speed of the extruder and changing the discharge amount of the material constituting the colored layer 32. A colored layer 32 having a thickness can be formed.

  The inventor produced samples of the transmission screen 16 shown in FIG. 5 and the transmission screen 16 shown in FIG. In these samples, the colored layer 32 is optimized by a two-layer extrusion molding method, and the light control layer 33 is formed by wiping molding. Further, a deflection optical plate is manufactured by bonding a Fresnel lens to a transparent polycarbonate plate serving as a support by an ultraviolet curable adhesive resin, and the deflection optical plate is a laminated plate (anisotropic light diffusion layer 30, isotropic light diffusion layer 31, colored layer). 32, the light control layer 33, and the rigid layer 34) were used as a sample of the transmission screen 16 in FIG. 5 and a sample of the transmission screen 16 in FIG. The thickness of the colored layer 32 in the sample of the transmission screen 16 in FIG. 5 is 250 μm (micrometer), and the thickness of the colored layer 32 in the sample of the transmission screen 16 in FIG. 6 is 1.3 mm (millimeter). It was.

  Then, the inventor uses the sample of the transmissive screen 16 of FIG. 5 and the sample of the transmissive screen 16 of FIG. 6 to project from the image light source 14 onto the transmissive screen 16 and exit from the transmissive screen 16. The image light L1 was visually observed.

  FIG. 7 shows an observation example of the image light L1 projected on the transmission screen 16 of FIG. FIG. 8 shows an observation example of the image light L1 projected on the transmission screen 16 of FIG. As is clear from a comparison between FIGS. 7A to 7B and FIGS. 8A to 8B, the transmission screen 16 in FIG. 5 is superior to the transmission screen 16 in FIG. Visibility is shown. The inventor of the present invention has an image shift amount d of a partial region of the observation image shown in FIGS. 7B and 8B (a region indicated by reference numeral “R” in FIGS. 7B and 8B). It was confirmed. In the observation image obtained by the transmission screen 16 in FIG. 5 (see FIG. 7B), the theoretical value of the image shift amount d is 0.15 mm. However, the image shift amount d cannot be visually recognized in actual measurement. there were. On the other hand, in the observation image obtained by the transmission screen 16 in FIG. 6 (see FIG. 8B), the theoretical value of the image displacement amount d is 0.7 to 0.8 mm, and the actual measured image displacement. The quantity d was 0.8 mm.

  In this way, by forming the thin colored layer 32 and narrowing the distance between the isotropic light diffusion layer 31 and the light control layer 33, it is possible to effectively prevent the generation of multiple images and to observe images with excellent visibility. Can be provided. Hereinafter, a mechanism for generating multiple images will be described.

<Multiple image generation mechanism>
FIG. 9 is a conceptual diagram illustrating a partially enlarged cross section of the isotropic light diffusing layer 31, the colored layer 32, and the light control layer 33, and illustrating a mechanism for generating multiple images.

  The image light L1 incident on the transmission screen 16 is diffused in the isotropic light diffusion layer 31 as described above, travels in various directions, passes through the colored layer 32 and the light control layer 33, and exits from the transmission screen 16. To do. Accordingly, the image light L1 is diffused by the isotropic light diffusion layer 31 and proceeds in parallel with the “real image light Ri (in the example shown in FIG. 9,“ in the thickness direction of the transmission screen 16 (see arrow “X”)). ”And“ ghost image light Gi (in the example shown in FIG. 9, “non-parallel to the thickness direction of the transmissive screen 16 (see arrow“ X ”)). , And is output from the transmissive screen 16 by being divided into “indicated by an arrow“ reflected by the unit light absorbing portion 38 and passing through the unit light transmitting portion 37 ”.

  Since the observer 10 visually recognizes the real image light Ri and the ghost image light Gi at the same time, the larger the deviation amount between the real image light Ri and the ghost image light Gi, the more clearly the multiple images are perceived in the observation image. The amount of deviation between the real image light Ri and the ghost image light Gi depends on the distance between the isotropic light diffusion layer 31 and the light control layer 33. Therefore, when the colored layer 32 is disposed between the isotropic light diffusing layer 31 and the light control layer 33, the larger the size in the thickness direction of the colored layer 32 (see arrow “X” in FIG. 9), the more clearly. The observed multiple images tend to be observed by the observer 10, and the smaller the size in the thickness direction of the colored layer 32, the more difficult it is for the observer 10 to visually recognize the multiple images, thereby improving the visibility of the image. Therefore, in order to prevent the generation of multiple images and achieve good visibility, the distance between the isotropic light diffusion layer 31 and the light control layer 33 (the thickness of the colored layer 32 in the above embodiment) is made as small as possible. It is preferable to do.

  As described above, the transmissive screen 16 according to the above-described embodiment is provided with the light control layer 33 and anisotropy by reducing the distance between the isotropic light diffusion layer 31 and the light control layer 33. It is possible to provide the observer 10 with an image with excellent visibility by effectively preventing the generation of multiple images while realizing a viewing angle with high accuracy.

<Specific example>
FIG. 10 is a partially enlarged cross-sectional view of the unit light absorbing portion 38 of the light control layer 33, and (a) to (c) are diagrams for explaining the angular relationship related to the unit light absorbing portion 38, respectively.

  The cross-sectional shape of each unit light absorbing portion 38 (the cross-sectional shape along both the arrow “X” and the arrow “Z” in FIG. 9) has a line-symmetric isosceles trapezoidal shape as shown in FIG. In this case, the “leg portion 38c” of the unit light absorbing portion 38 is “a reference line perpendicular to the upper bottom portion 38a and the lower bottom portion 38b (a line from the light incident surface 18 to the light emission surface 20 (a line along the arrow X in FIG. 9)). The angle (taper angle) formed with respect to “]” (refer to the dotted line in FIG. In this case, the length of the upper bottom portion 38a of each unit light absorbing portion 38 is represented by “a”, the length of the lower bottom portion 38b is represented by “b”, and the height (between the upper bottom portion 38a and the lower bottom portion 38b). When the distance) is represented by “h”, the following relational expression is established.

<Relational expression 1>
tan (θ1) = (ba) / 2 / h

  On the other hand, as shown in FIG. 10B, out of the image light L1 traveling toward the unit light absorber 38, the image light L1 totally reflected by the legs 38 c of the unit light absorber 38 is unit light absorber 38. The angle θ2 formed with respect to the leg portion 38c (particularly, the angle when the incident angle with respect to the unit light absorbing portion 38 is the smallest) θ2 is represented by the following relational expression. The “critical angle” in the following relational expression is “critical angle = arcsin (arcsin () based on the refractive index n1 of the unit light transmitting portion 37 and the refractive index n2 of the unit light absorbing portion 38 constituting the interface from Snell's law. n2 / n1) ".

<Relational expression 2>
θ2 = 90 ° −critical angle = 90 ° −arcsin (n2 / n1)

  Then, as shown in FIG. 10C, the image light L1 traveling in the unit light transmitting portion 37 toward the unit light absorbing portion 38 (light control layer 33) (but before entering the unit light absorbing portion 38). The angle θ3 formed by the image light L1) with respect to “a reference line perpendicular to the upper bottom portion 38a and the lower bottom portion 38b (a line from the light incident surface 18 to the light emission surface 20; see the dotted line in FIG. 10C)” is It is expressed by the relational expression.

<Relational expression 3>
θ3 = θ1 + θ2

  FIG. 11 shows partial enlarged cross sections of the isotropic light diffusion layer 31, the colored layer 32, and the light control layer 33, and an example of the relationship between the interval Δd between the real image light Ri and the ghost image light Gi and the thickness T of the colored layer 32 will be described. It is a conceptual diagram for.

  As is clear from FIG. 11, the relationship between “the distance Δd between the real image light Ri and the ghost image light Gi” and “the thickness T of the colored layer 32” is based on the angle θ3 formed by the video light L1 with respect to the reference line. Is expressed by the following relational expression.

<Relational expression 4>
tan (θ3) = Δd / T
T = Δd / tan (θ3)
Δd = T × tan (θ3)

  Therefore, for example, the length a of the upper bottom portion 38a of each unit light absorbing portion 38 is “a = 3.5 μm”, the length b of the lower bottom portion 38b is “b = 22 μm”, and the height h is “h = In the case of “118 μm”, “tan (θ1) = (22 μm−3.5 μm) / 2/118 μm” is established from the relational expression 1, and “θ1≈4.5 °” is derived from the relational expression. On the other hand, when the refractive index n1 of the unit light transmitting portion 37 is “n1 = 1.55” and the refractive index n2 of the unit light absorbing portion 38 is “n2 = 1.49”, the relational expression 2 above yields “θ2 = 90 ° -arcsin (1.49 / 1.55) ≈16.0 ° ”. Therefore, from the above relational expression 3, “θ3 = 4.5 ° + 16.0 ° = 20.5 °” is derived. Therefore, the symbol “θ4” in FIG. 11 becomes “θ4 = 90 ° −θ3 = 69.5 °”.

  Based on the thus derived angle θ3 (= 20.5 °) with respect to the reference line of the image light L1, “the sample of the transmissive screen 16 in FIG. 5 in which the thickness of the colored layer 32 is 250 μm” as described above. And “a sample of the transmission screen 16 of FIG. 6 in which the thickness of the colored layer 32 is 1.3 mm” was considered. That is, in the case of “T = 1300 μm = 1.3 mm” in the sample of the transmission screen 16 of FIG. 6 in which the thickness T of the colored layer 32 is relatively large, “the distance Δd between the real image light Ri and the ghost image light Gi” is From the above relational expression 4, “Δd = 1.3 mm × tan (20.5 °) ≈0.486 mm”. On the other hand, when “T = 250 μm = 0.25 mm” in the sample of the transmission screen 16 of FIG. 5 in which the thickness T of the colored layer 32 is relatively small, “the distance Δd between the real image light Ri and the ghost image light Gi” is From the above relational expression 4, “Δd = 0.25 mm × tan (20.5 °) ≈0.09 mm”.

  The “interval Δd between the real image light Ri and the ghost image light Gi” thus obtained is a factor that determines the image shift amount d of the multiple image shown in the example of FIG. As is clear from the relational expressions 1 to 4 described above, when the thickness T of the colored layer 32 increases (for example, T = 1.3 mm), the “interval Δd between the real image light Ri and the ghost image light Gi” also increases. (For example, Δd = 0.486 mm), it becomes easier for the observer 10 to visually recognize multiple images. On the other hand, when the thickness T of the colored layer 32 decreases (for example, T = 0.25 mm), the “interval Δd between the real image light Ri and the ghost image light Gi” also decreases (for example, Δd = 0.09 mm). It becomes difficult to visually recognize multiple images.

  Normally, when the “interval Δd between the real image light Ri and the ghost image light Gi” is about 0.2 mm, the observer 10 tends to start visually recognizing the multiple images. Further, regarding the length a of the upper base portion 38a, the length b and the height h of the lower base portion 38b of the unit light absorbing portion 38, in consideration of the size of a normally used range, θ1 derived from the relational expression 1 is generally “ 4.482 ° to 4.498 ° ". In consideration of the refractive index n1 of the unit light transmitting portion 37 and the refractive index n2 of the unit light absorbing portion 38 that are normally used, θ2 derived from the relational expression 2 is generally “16 ° to 19.4 °”. Become. Therefore, θ3 derived from the above relational expression 3 is generally “20.5 ° or more and 23.9 ° or less”. Therefore, the above-described “interval Δd = 0.2 mm between the real image light Ri and the ghost image light Gi” at which the multiple image starts to be visually recognized and the general size of the angle θ3 formed by the video light L1 with respect to the reference line (that is, 20.5 ° or more and 23.9 ° or less), it can be seen from the above relational expression 4 that the thickness T of the colored layer 32 is preferably 0.451 mm or more and 0.535 mm or less. The colored layer 32 may be made by further taking into account the processing capability of the extrusion molding machine. For example, considering the processing capability of the extrusion molding machine, the thickness T of the colored layer 32 may be 0.06 mm. Therefore, the thickness T of the colored layer 32 may be 0.060 mm or more and 0.535 mm.

<Method for Manufacturing Transmission Screen 16>
The transmission screen 16 described above can be manufactured based on any method. For example, in the case of the transmissive screen 16 including a deflecting optical plate and a laminated plate, a laminated plate (see FIGS. 3 and 5 described above) is prepared first, and then various elements constituting the deflecting optical plate are placed on the laminated plate (described above). In this embodiment, the transmissive screen 16 can be manufactured by being formed on the anisotropic light diffusion layer 30). In the case of manufacturing the curved transmission screen 16, it is preferable to prepare a curved laminated plate in advance and form a deflection optical plate on the curved laminated plate.

<Modification>
The present invention is not limited to the above-described embodiment, and various modifications may be added to the above-described embodiment, and partial configurations of the above-described embodiment and modification examples may be combined with each other.

  For example, in the above-described embodiment, the colored layer 32 is disposed between the isotropic light diffusion layer 31 and the light control layer 33, but the arrangement position of the colored layer 32 is not limited to this position. For example, even if the colored layer 32 is disposed “between the isotropic light diffusion layer 31 and the anisotropic light diffusion layer 30”, “light emission side from the light control layer 33” or “light input side from the anisotropic light diffusion layer 30”. Good.

  1 and 2 show an example in which the image light L1 is directly emitted from the image light source 14 to the transmission screen 16 (light incident surface 18), but the present invention is not limited to this. FIG. 12 is a diagram schematically showing a modification of the display device 12. The display device 12 illustrated in FIG. 12 further includes a mirror unit 23 in addition to the video light source 14 and the transmissive screen 16 described above, and the mirror unit 23 reflects the video light L1 from the video light source 14 to reflect the transmissive screen 16. Project to.

  Thus, the image light L1 emitted from the image light source 14 may be applied to the transmission screen 16 via an optical element such as a mirror unit 23, a prism unit, or a lens. For example, the optical path of the image light L1 can be adjusted by interposing a mirror unit 23, a prism unit, or the like between the image light source 14 and the transmission screen 16, and the image can be enlarged or expanded by interposing a lens or the like. The reduced image light L1 can be applied to the transmission screen 16. Further, these plural types of optical elements are arranged between the image light source 14 and the transmission screen 16, and the image light L1 after the optical path is changed by enlarging or reducing the image is transmitted to the transmission screen 16 ( The light incident surface 18) may be irradiated.

  1 and 2 exemplify the transmissive screen 16 that is curved so that the light incident surface 18 is convex as a whole and the light output surface 20 is concave as a whole. It is not limited. FIG. 13 is a diagram schematically showing another modification of the display device 12. As shown in FIG. 13, the transmission screen 16 may be curved so that the light incident surface 18 is concave as a whole and the light output surface 20 is convex as a whole. The transmission screen 16 may be formed in a flat plate shape, and each of the light incident surface 18 and the light exit surface 20 may be a flat surface as a whole.

  Further, in the above-described embodiment, the anisotropic light diffusion layer 30 is configured by the layer having the wedge-shaped unit light diffusion portion 40, but the anisotropic light diffusion layer 30 diffuses light (image light L1) anisotropically. Other configurations are possible as long as they are possible. For example, the anisotropic light diffusion layer 30 may be configured by an optical element such as a lenticular lens. Strictly speaking, the “anisotropic light diffusion layer 30 having a plurality of unit light diffusion portions 40” as shown in FIG. 5 can also be regarded as a reflective (total reflection type) lenticular lens. The anisotropic light diffusion layer 30 can also be configured by a lenticular lens. For example, a lenticular lens disclosed in Japanese Patent Application Laid-Open No. 2004-287119 can be used as the anisotropic light diffusion layer 30.

  The transmissive screen 16 may include members other than the above-described deflecting optical plate and laminated plate (anisotropic light diffusing layer 30, isotropic light diffusing layer 31, colored layer 32, light control layer 33, and rigid layer 34). Other functional layers expected to exhibit a specific function may be provided. In that case, the single functional layer may exhibit two or more functions, and at least one of the anisotropic light diffusion layer 30, the isotropic light diffusion layer 31, the colored layer 32, the light control layer 33, and the rigid layer 34 described above. Other functions may be given to one element. Functions that can be imparted to the transmissive screen 16 are not particularly limited. As an example, a hard coat (HC) function, antifouling function, antiglare (AG) function, and reflection that exhibit scratch resistance are exemplified. Examples thereof include an anti-reflection (AR) function.

  The embodiments of the present invention are not limited to the above-described individual embodiments, but include various modifications that can be conceived by those skilled in the art, and the effects of the present invention are not limited to the above-described contents. That is, various additions, changes, and partial deletions can be made without departing from the concept and spirit of the present invention derived from the contents defined in the claims and equivalents thereof.

DESCRIPTION OF SYMBOLS 10 Observer 12 Display apparatus 14 Image | video light source 16 Transmission type screen 18 Light-incident surface 20 Light-emitting surface 23 Mirror part 30 Anisotropic light diffusion layer 31 Isotropic light diffusion layer 32 Colored layer 33 Light control layer 34 Rigid layer 36 Base 37 Unit light transmission part 38 Unit light absorber 40 Unit light diffuser L1 Image light Ri Real image light Gi Ghost image light

Claims (10)

A transmissive screen that transmits image light projected from the light incident side to the light output side,
An anisotropic light diffusion layer for anisotropically diffusing incident light;
An isotropic light diffusing layer that is disposed on the light exit side of the anisotropic light diffusing layer and diffuses incident light isotropically;
A colored layer containing a colorant;
A light control layer that is disposed on the light output side of the isotropic light diffusion layer and includes a plurality of unit light transmission portions and a plurality of unit light absorption portions disposed between the plurality of unit light transmission portions. Mold screen.   The transmissive screen according to claim 1, wherein the colored layer is disposed between the anisotropic light diffusion layer and the light control layer.   The transmissive screen according to claim 2, wherein the colored layer is in contact with the isotropic light diffusion layer on one of the light incident side and the light output side of the isotropic light diffusion layer.   The transmissive screen according to claim 3, wherein a total thickness of the isotropic light diffusion layer and the colored layer related to the light exit side from the light entrance side is smaller than 500 μm.   The transmission type screen according to any one of claims 1 to 3, wherein the colored layer has a thickness of 0.060 mm to 0.535 mm.   The anisotropic light diffusion layer has a plurality of unit light diffusion portions, and each of the plurality of unit light diffusion portions extends in a direction non-parallel to a direction in which each of the plurality of unit light absorption portions extends. Item 6. The transmissive screen according to any one of Items 1 to 5.   The transmissive screen according to claim 1, which has a curved shape and has a curved screen surface.   The transmissive screen according to claim 1, further comprising a rigid layer. Each of the plurality of unit light absorbing portions and each of the plurality of unit light transmitting portions extends in the left-right direction in the usage state of the transmission type screen,
The plurality of unit light absorption units and the plurality of unit light transmission units are arranged side by side in an up-down direction perpendicular to the left-right direction in the usage state of the transmissive screen. A transmissive screen according to 1. The transmission screen according to any one of claims 1 to 9,
A display device, comprising: an image light source disposed on a rear side of the transmissive screen and projecting image light onto the transmissive screen.