JP7516796B2 - Reflective screen, image display device - Google Patents

Description

The present invention relates to a light control member and a reflective screen and image display device equipped with the same.

Conventionally, various reflective screens have been developed that display images by reflecting the image light projected from an image source. Among these, there is growing demand for reflective screens (semi-transmissive reflective screens) that can be used as reflective screens that project image light and allow images to be clearly seen, and that have transparency that allows the scenery on the other side of the screen to be seen when not in use and not projecting image light, due to their high designability, etc. (see, for example, Patent Document 1).

JP 2017-156452 A

However, in a transparent reflective screen as described above, part of the image light also passes through the reflective screen. Therefore, for example, when a transparent reflective screen is used as a show window or an indoor partition, there is a problem that the image is reflected by the transmitted image light onto a person or object located on the other side of the show window or partition, or the projected image is reflected on the ceiling, etc.

To eliminate this kind of glare in the projected image, for example, a louver film with an array of light-absorbing parts that absorb light could be placed on the back side of a transparent reflective screen. However, with such a louver film, the view (transmitted image) when viewed through the screen becomes dark, and diffraction occurs due to the finely arranged light-absorbing parts, reducing the transparency of the screen.

The objective of the present invention is to provide a light control member that eliminates the reflection of a projected image on a ceiling or the like, and a reflective screen and image display device that include the same.

The present invention solves the above problems by the following solving means. Note that, for ease of understanding, the following description will be given with reference numerals corresponding to the embodiments of the present invention, but the present invention is not limited thereto.
A first invention is a light control member (30) that is a sheet-like light control member that exhibits at least one of the functions of diffusing or blocking at least a portion of light incident from a specific direction, and that has at least one of the functions of diffusing or blocking at least a portion of the incident light, and is characterized in that it comprises: transmitted light suppression sections (35) that have a predetermined dimension in the thickness direction of the light control member and are arranged along the sheet surface of the light control member; light transmission sections (32, 34) that are provided between adjacent transmitted light suppression sections; and a low refractive index layer (33) that is provided within the light transmission sections and inclined at a predetermined angle with respect to the thickness direction of the light control member, and has a refractive index lower than that of the light transmission sections, and the transmitted light suppression sections at least one of the functions of diffusing or blocking light that is incident thereon and travels straight through the interior to transmit therethrough, and has the function of reducing the amount of light in the straight traveling direction.
A second invention is a light control member (30) according to the first invention, characterized in that in the thickness direction of the light control member, contacting portions (32, 34) located on both sides of the low refractive index layer (33) of the light transmitting portion (32, 34) have the same refractive index.
A third invention is a light control member (30) characterized in that, in the light control member of the first or second invention, the transmitted light suppression portion (35) is formed in a band shape extending in a first direction along the sheet surface of the light control member and arranged in a second direction intersecting the first direction, and the cross-sectional shape in a cross section parallel to the second direction and the thickness direction of the light control member is wedge-shaped.
A fourth invention is a light control member (30) characterized in that, in any of the light control members from the first to third inventions, the transmitted light suppression portion (35) contains a light-transmitting resin material that contains a light-diffusing material that has a refractive index different from that of the resin material and is light-transmitting, and diffuses at least a portion of the incident light.
A fifth invention is a light control member (30) according to the fourth invention, characterized in that the refractive index of the light diffusing material is smaller than the refractive index of the resin material.
A sixth invention is a light control member (30) characterized in that, in any of the light control members from the first to fifth inventions, the transmitted light suppression portion (35) contains a light absorbing material that absorbs light, and absorbs at least a portion of the incident light.
The seventh invention is a reflective screen that displays an image by reflecting a portion of the projected image light, comprising a semi-transmissive reflective layer (23) that reflects a portion of the incident light, transmits a portion of the light, and has an uneven shape on its surface that diffuses the light, and comprises a screen portion (20) that displays an image by reflecting a portion of the projected image light, and a light control member (30) according to any one of the first to sixth inventions that is arranged on the back side of the screen portion, opposite the image source side in the thickness direction.
The eighth invention is a reflective screen (10) characterized in that, in the reflective screen of the seventh invention, the angle (α) that the low refractive index layer (33) makes with the thickness direction of the light control member (30) is larger than the angle that the image light transmitted through the reflective layer (23) makes with the thickness direction of the light control member in the light transmitting portion (32).
The ninth invention is a reflective screen (10) characterized in that in any one of the 7th to 8th inventions, the screen portion (20) does not contain a diffusing material that diffuses light.
The tenth invention is a reflective screen (10) characterized in that, in any one of the 7th to 9th inventions, a unit optical shape (221) having optical transparency and a first surface (221a) on which image light is incident and a second surface (221b) intersecting the first surface has a plurality of optical shape layers (22) arranged on the rear surface, and the reflective layer (23) is formed on at least the first surface of the unit optical shape.
An eleventh invention is an image display device (1) comprising a reflective screen (10) according to any one of the seventh to tenth inventions, and an image source (LS) that projects image light onto the reflective screen.

The present invention provides a light control member that eliminates the glare of a projected image on a ceiling or the like, and a reflective screen and image display device that include the light control member.

1 is a diagram showing an image display device 1 according to an embodiment. 1 is a diagram showing a layer structure of a screen 10 according to an embodiment. 3A and 3B are diagrams illustrating a lens layer 22 according to the embodiment. FIG. 2 is a diagram illustrating a light control unit 30 according to the embodiment. 2A to 2C are diagrams for explaining how light incident on a screen 10 of an embodiment travels.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings, etc. Note that each of the drawings shown below, including Fig. 1, is a schematic diagram, and the size and shape of each part are appropriately exaggerated to facilitate understanding.
In this specification, terms specifying shapes or geometric conditions, such as parallel and orthogonal, are intended to include not only their strict meanings but also states that have a similar optical function and have an error that can be regarded as parallel or orthogonal.

Furthermore, the terms plate, sheet, film, etc. are used in this specification, and in general, these are used in the order of thickness, plate, sheet, film, etc., and this specification follows that order. However, since there is no technical meaning in this distinction, these terms can be used interchangeably as appropriate.
In this specification and claims, the screen surface refers to a surface that is in the planar direction of the screen when viewed as a whole, and is parallel to the image plane (display surface) of the screen. In this specification and claims, the sheet surface refers to a surface that is in the planar direction of the sheet when viewed as a whole sheet-like member.

(Embodiment)
Fig. 1 is a diagram showing an image display device 1 according to the present embodiment. Fig. 1(a) is a perspective view of the image display device 1, and Fig. 1(b) is a view of the image display device 1 as seen from the side (the +X side described later).
The image display device 1 includes a screen 10, an image source LS, etc. The screen 10 of this embodiment is a reflective screen that reflects image light L projected from the image source LS and displays an image on its screen. The details of the screen 10 will be described later.
In this embodiment, as an example, it is assumed that the image display device 1 is applied to a shop window, and the screen 10 is fixed to the glass of the shop window (not shown).

For ease of understanding, an XYZ Cartesian coordinate system is provided as appropriate in each of the following figures, including Fig. 1. In this coordinate system, the left-right direction of the screen of the screen 10 is the X direction, the up-down direction is the Y direction, and the thickness direction of the screen 10 is the Z direction. The screen of the screen 10 is parallel to the XY plane, and the thickness direction (Z direction) of the screen 10 is perpendicular to the screen of the screen 10. The screen 10 of this embodiment is arranged so that the screen is parallel to the vertical and horizontal directions when in use.
In addition, the direction toward the right side in the left-right direction when viewed from an observer O positioned in front of the screen 10 is the +X direction, the direction toward the upper side in the up-down direction is the +Y direction, and the direction from the back side (rear side) toward the image source side (observer side) in the thickness direction is the +Z direction.
Furthermore, in the following description, unless otherwise specified, the up-down direction, left-right direction, and thickness direction of the screen refer to the up-down direction (vertical direction), left-right direction (horizontal direction), and thickness direction (depth direction) of the screen 10 when in use, and are parallel to the Y direction, X direction, and Z direction, respectively.

The image source LS is an image projection device that projects image light L onto the screen 10, and is, for example, a short-focus projector.
When the image display device 1 is in use, this image source LS is located in the center of the screen 10 in the left-right direction and vertically below the screen of the screen 10 when the screen (display area) of the screen 10 is viewed from the front (normal direction to the screen surface).
The image source LS can project the image light L obliquely from a position that is much closer to the surface of the screen 10 in the depth direction (Z direction) of the image display device 1 than a conventional general-purpose projector. Therefore, compared to a conventional general-purpose projector, the image source LS has a shorter projection distance to the screen 10 and a larger incidence angle at which the projected image light L is incident on the screen 10.

The screen 10 is a reflective screen that reflects the image light L projected by the image source LS toward the observer O to display the image, and is also a semi-transmissive reflective screen that is transparent so that the observer O can observe the scenery (transmitted image) on the other side of the screen 10 (-Z side) through the screen 10.
The image plane (display area) of the screen 10 has a rectangular shape with its longer side extending in the left-right direction (X direction) of the screen when viewed from the observer O side in a used state.
The screen 10 has a large screen size of about 80 to 100 inches diagonally, and the aspect ratio of the screen is 16:9. However, the screen size is not limited to this, and may be, for example, about 40 inches or less, and the size and shape can be appropriately selected depending on the purpose of use, the environment in which it is used, etc.

Generally, the screen 10 is a laminate of thin resin layers, and in many cases does not have sufficient rigidity to maintain flatness by itself. Therefore, the screen 10 is integrally joined (or partially fixed) to a support plate (not shown) via a light-transmitting joining layer (not shown) on the back side (-Z side) of the screen 10, thereby maintaining the flatness of the screen.
The support plate (not shown) is a plate-like member that is optically transparent and has high rigidity, and may be made of a plate-like member made of resin such as acrylic resin or PC resin, glass, etc. In this embodiment, the image display device 1 is applied to a show window of a store or the like, and the support plate is window glass.
The screen 10 is not limited to the above example, and may have four sides supported by a frame member (not shown) or the like to maintain its flatness.

Fig. 2 is a diagram showing the layer structure of the screen 10 of this embodiment. Fig. 2 shows an enlarged portion of a cross section that passes through point A (see Figs. 1(a) and (b)) which is the screen center (geometric center of the screen) of the screen 10, is parallel to the up-down direction of the screen (Y direction), and is perpendicular to the screen surface (parallel to the Z direction).
As shown in FIG. 2, the screen 10 includes, in order from the image source side (+Z side), a screen section 20 and a light control section 30, which are integrally bonded together by a bonding layer 40.

The screen portion 20 is not particularly limited in its form as long as it is a member that can be used as a transparent reflective screen. In this embodiment, an example is described in which the screen portion 20 includes, in order from the image source side (+Z side) along the thickness direction (Z direction) of the screen 10, a first base material layer 21, a lens layer 22, a reflective layer 23, a planarization layer 24, and a second base material layer 25.
In addition, the light control unit 30 is a sheet-like member that has the function of diffusing light incident from a predetermined direction (angle range), and is provided with, in order from the image source side (+Z side) along the thickness direction (Z direction) of the screen 10, a first base material layer 31, a first light-transmitting section 32, a low refractive index layer 33, a second light-transmitting section 34, a diffusion section 35 (transmitted light suppression section), and a second base material layer 36.
The bonding layer 40 is a layer having optical transparency and having a function of bonding the screen unit 20 and the light control unit 30. The bonding layer 40 can be made of an adhesive, a pressure sensitive adhesive, or the like having optical transparency.

The first base layer 21 of the screen unit 20 is a sheet-like member having optical transparency. The first base layer 21 has a lens layer 22 integrally formed on its rear side (−Z side). The first base layer 21 is a layer that serves as a base material (base) for forming the lens layer 22.
The first base layer 21 is formed, for example, from a polyester resin such as PET (polyethylene terephthalate) having high light transmittance, an acrylic resin, a styrene resin, an acrylic-styrene resin, a PC (polycarbonate) resin, an alicyclic polyolefin resin, a TAC (triacetyl cellulose) resin, or the like.

Fig. 3 is a diagram illustrating the lens layer 22 of this embodiment. Fig. 3(a) is a diagram of the lens layer 22 as viewed from the rear side (-Z side), and for ease of understanding, only the lens layer 22 is shown, with the other layers of the screen unit 20 and the light control unit 30 omitted. Fig. 3(b) shows an enlarged view of a portion of the cross section of the screen unit 20 corresponding to the cross section of the screen 10 shown in Fig. 2 described above.
The lens layer 22 is a light-transmitting layer formed on the rear side (−Z side) of the first base layer 21. A plurality of unit lenses 221 are arranged on the surface of the rear side of the lens layer 22.

The lens layer 22 in this embodiment has a circular Fresnel lens shape on the back surface side. As shown in Fig. 3A, the circular Fresnel lens shape of the lens layer 22 is a so-called offset structure circular Fresnel lens shape having a center (Fresnel center) of a point C located outside the screen (display area) of the screen 10.
As shown in Figure 3 (a), when the lens layer 22 is viewed from the rear side in the normal direction of the screen surface, the unit lenses 221 have a shape of a part of a perfect circle (arc shape), and are arranged in multiple concentric circles with point C as the center.
As shown in FIG. 3(a), this point C and the aforementioned point A are located on a straight line parallel to the vertical direction (Y direction) of the screen when the lens layer 22 is viewed from the thickness direction (Z direction) of the screen 10.

The unit lenses 221 are parallel to a direction (Z direction) perpendicular to the screen surface, and have a substantially triangular cross section in a cross section parallel to the arrangement direction of the unit lenses 221 .
As shown in Fig. 3B, each unit lens 221 is convex on the rear side and has a lens surface 221a on which image light is incident and a non-lens surface 221b on which image light is not incident. In the cross section shown in Fig. 3B, the lens surface 221a and the non-lens surface 221b intersect with each other.
In one unit lens 221, the lens surface 221a is located above (on the +Y side of) the non-lens surface 221b with the vertex t1 in between.

3B, in the unit lens 221, the angle (lens angle) that the lens surface 221a makes with a plane parallel to the screen surface (XY plane) is θ1, and the angle that the non-lens surface 221b makes with a plane parallel to the screen surface is θ2. In this case, the angles θ1 and θ2 satisfy the relationship θ2>θ1.
The lens surface 221a and the non-lens surface 221b of each unit lens 221 have a minute uneven shape.

The arrangement pitch of the unit lenses 221 is P1, and the height of the unit lens 221 (the dimension from the vertex t1 in the thickness direction to the point t2 which is the bottom between the unit lenses 221) is h1.
2 shows an example in which the angles θ1, θ2, the arrangement pitch P1, etc. are constant. However, in the screen unit 20 of this embodiment, the arrangement pitch P1 and the angle θ2 are actually constant, and the angle θ1 gradually increases as it moves away from the point C that is the Fresnel center. However, without being limited to this, these angles and dimensions may be appropriately set according to the projection angle of the image light from the image source LS (the incident angle of the image light to the screen 10), the size of the pixels of the image source LS, the screen size of the screen 10, the refractive index of each layer, etc. For example, a form in which at least one of these angles and dimensions changes continuously or stepwise along the arrangement direction of the unit lenses 221 may be used.

The lens layer 22 is formed of an ultraviolet-curable resin having high optical transparency, such as a urethane acrylate, polyester acrylate, epoxy acrylate, polyether acrylate, polythiol, or butadiene acrylate.
In this embodiment, the resin constituting the lens layer 22 is described using an ultraviolet curable resin as an example, but the present invention is not limited to this, and the lens layer 22 may be formed of other ionizing radiation curable resins, such as electron beam curable resins.

The reflective layer 23 is a layer formed on at least the lens surface 221a of each unit lens 221. In this embodiment, the reflective layer 23 is formed on the lens surface 221a and the non-lens surface 221b of each unit lens 221.
As described above, the lens surface 221a and the non-lens surface 221b are formed with a fine uneven shape, and the reflective layer 23 is formed to follow this fine uneven shape. The thickness of the reflective layer 23 is also sufficiently thinner than the uneven shape. Therefore, the reflective surface of the reflective layer 23 (the surface of the reflective layer 23 on the lens layer 22 side) is a rough surface with a fine uneven shape.
From the viewpoint of displaying an image satisfactorily by reflected light, it is preferable that the surface roughness of the reflecting surface of the reflecting layer 23 (i.e., the surface roughness of the lens surface 221a) is about 0.15 to 0.3 μm in arithmetic mean roughness Ra (JIS B0601-2001). The arithmetic mean roughness Ra, which is the surface roughness of the reflecting surface of the reflecting layer 23 (i.e., the surface roughness of the lens surface 221a), may be appropriately selected depending on the desired optical performance, etc.

The reflective layer 23 is a semi-transmissive reflective layer that reflects a part of the incident light and transmits at least a part of the rest, that is, a so-called half mirror.
The ratio of the reflectance and transmittance of the reflective layer 23 can be set as appropriate, but from the viewpoint of favorably reflecting the image light and favorably transmitting light other than the image light (for example, light from the outside world such as sunlight), it is desirable that the reflectance be in the range of 5 to 60% and the transmittance be in the range of 30 to 80% for light incident on the reflective layer 23 at an incident angle of 0°.
The reflective layer 23 of this embodiment is formed in a half-mirror shape having a reflectance of about 10% and a transmittance of about 50% for light incident on the reflective layer 23 at an incident angle of 0°.
Therefore, the reflective layer 23 of the present embodiment has the function of diffusing and reflecting part of the incident light by the fine unevenness of the reflective surface, and transmitting part of the incident light without diffusing it.

The reflective layer 23 is made of a metal having high light reflectivity, such as aluminum, silver, nickel, etc., and has a thickness of about several tens of angstroms. The reflective layer 23 in this embodiment is formed by vapor deposition of aluminum.
The reflective layer 23 is not limited to this, and may be formed, for example, by sputtering a metal having high light reflectivity, transferring a metal foil, applying paint containing a thin metal film, or may be formed, for example, by vapor deposition of a dielectric multilayer film.

The planarization layer 24 is a light-transmitting layer provided on the back side (−Z side) of the lens layer 22. The planarization layer 24 is provided to flatten the surface on the back side of the lens layer 22, and is formed so as to fill in valleys between adjacent unit lenses 221. Therefore, the surface on the image source side (+Z side) of the planarization layer 24 is formed by arranging a plurality of unit lens shapes that are approximately the inverse of the unit lenses 221 of the lens layer 22.
By providing such a planarizing layer 24, the reflective layer 23 can be protected, and the second base layer 25, the light control unit 30, and the like can be easily laminated.
In order to improve the transparency of the screen 10, it is desirable that the refractive index of the planarization layer 24 be the same as that of the lens layer 22, and it is preferable that the planarization layer 24 is formed using the same ultraviolet-curing resin or the like as the lens layer 22 described above.

The second base layer 25 is a layer provided on the back surface side (−Z side) of the planarizing layer 24 .
A sheet-like member made of a resin having high light transmittance is used as the second base layer 25. The second base layer 25 may be, for example, a sheet-like member formed using the same material as the first base layer 21 described above.
As described above, the screen portion 20 does not have a light diffusion layer containing light diffusion material such as particles having a diffusing effect, and only the fine uneven shape of the reflective surface of the reflective layer 23 has a diffusing effect.

Fig. 4 is a diagram for explaining the light control unit 30 of this embodiment. Fig. 4 shows a further enlarged view of a part of the cross section of the light control unit 30, which corresponds to the cross section of the screen 10 shown in Fig. 2 described above, with the screen unit 20 omitted.
The light control unit 30 is a sheet-like member that exhibits at least one of the functions of diffusing or blocking at least a portion of light incident from a specific direction. The light control unit 30 of this embodiment has a function of diffusing and transmitting most of the incident light from a specific direction (angle range) and transmitting most of the incident light from other directions (angle range) without diffusing it. In addition, the light control unit 30 of this embodiment selectively diffuses more of the image light that is projected from the image source LS located below the image source side of the screen 10 and that has passed through the reflective layer 23 of the screen unit 20 and entered the light control unit 30 than light that has entered from other directions, and transmits most of the other light without diffusing it.
As described above, the light control unit 30 includes, in order from the image source side, a first base material layer 31, a first light-transmitting section 32, a low refractive index layer 33, a second light-transmitting section 34, a diffusion section 35 (transmitted light suppression section), and a second base material layer 36.

The first base material layer 31 of the light control unit 30 is a sheet-like member having optical transparency, and the first light transmitting unit 32 is integrally formed on the back surface (−Z side) of the first base material layer 31. The first base material layer 31 is a layer that serves as a base material (base) for forming the first light transmitting unit 32.
The first base material layer 31 of the light control unit 30, like the first base material layer 21 of the screen unit 20 described above, is formed from, for example, a polyester resin such as PET (polyethylene terephthalate) having high light transmittance, an acrylic resin, a styrene resin, an acrylic-styrene resin, a PC (polycarbonate) resin, an alicyclic polyolefin resin, a TAC (triacetyl cellulose) resin, or the like.

The first light transmitting portions 32 are light transmitting portions formed on the rear surface (−Z side) of the first base layer 31. The first light transmitting portions 32 have a convex shape on the rear surface, and are arranged along the screen surface.
In the present embodiment, the first light transmitting portion 32 has, at its end on the image side, a continuous portion that is continuous in the XY plane between adjacent first light transmitting portions 32. Note that the first light transmitting portion 32 may have a form that does not have this continuous portion.
4 is a triangular shape that is convex on the rear side (−Z side), and is formed in a band shape such that the cross-sectional shape extends in a direction intersecting the arrangement direction of the first light transmitting portions 32. In this embodiment, the extension direction of the first light transmitting portions 32 is the left-right direction of the screen (X direction), and the arrangement direction of the first light transmitting portions 32 is the up-down direction of the screen (Y direction).

The first light transmitting portion 32 has a first surface 32a and a second surface 32b located on the upper side (+Y side) with a vertex t3 in between in the cross section of the light control portion 30 shown in FIG.
In the cross section of the light control unit 30 shown in Figure 4, the first surface 32a forms an angle θ3 [°] with respect to the thickness direction (Z direction) of the light control unit 30 (screen 10), and the second surface 32b forms an angle θ4 [°] with respect to the thickness direction (Z direction) of the light control unit 30 (screen 10).
This angle θ4 is larger than the angle θ3 and satisfies the relationship θ4>θ3.

The first light transmitting portion 32 is formed of an ultraviolet curing resin having high light transmittance, such as a urethane acrylate, polyester acrylate, epoxy acrylate, polyether acrylate, polythiol, or butadiene acrylate.
In this embodiment, it is preferable that the first light transmitting portion 32 has a refractive index of 1.54 or more from the viewpoint of efficiently totally reflecting the image light at the interface with the low refractive index layer 33 described later.
The first light transmitting portion 32 of the present embodiment is formed of an ultraviolet curable urethane acrylate resin (refractive index n1=1.55).
The resin constituting the first light transmitting portion 32 is not limited to the above-mentioned ultraviolet curable resin, but may be, for example, other ionizing radiation curable resins such as electron beam curable resins, or thermoplastic resins.

The low refractive index layer 33 is provided between adjacent diffusion sections 35 in the arrangement direction (Y direction) of the diffusion sections 35, and between the first light transmitting section 32 and the second light transmitting section 34 in the thickness direction (Z direction) of the screen section 20, and is a layer having a lower refractive index than the first light transmitting section 32 and the second light transmitting section 34 and having light transparency. The low refractive index layer 33 is provided at a position in contact with the second surface 32b of the first light transmitting section 32.

As shown in FIG. 4, the low refractive index layer 33 is inclined at an angle to the thickness direction of the screen section 20 (screen 10). The low refractive index layer 33 of this embodiment is inclined so that its upper (+Y side) end is located on the back side (-Z side) and its lower (-Y side) end is located on the image source side (+Z side), forming an angle θ4 [°] with the thickness direction of the screen section 20. In addition, the low refractive index layer 33 of this embodiment has its upper (+Y side) end in contact with the back side end of the adjacent diffusion section 35 above, and its lower (-Y side) end in contact with the image source side end of the adjacent diffusion section 35 below.

This angle θ4 is set so that the image light (image light Lt shown in FIG. 4) that is projected from below the image source side and enters the screen 10 and transmits through the reflective layer 23 of the screen unit 20 passes through the first light transmitting unit 32, enters the interface (second surface 32b) with the low refractive index layer 33 at an angle equal to or greater than the critical angle, and is totally reflected. Therefore, the angle θ4 is larger than the angle that the image light that has transmitted through the reflective layer 23 in the first light transmitting unit 32 makes with the thickness direction of the light control unit 30 (screen 10).
In view of the above, it is preferable that the angle θ4 be in the range of 30 to 80°, and more preferably in the range of 40 to 60°, from the viewpoint of efficiently directing unwanted image light Lt that has passed through the reflective layer 23 into the diffusion section 35.
If the angle θ4 is larger than this range, the image light that passes through the screen section 20 will pass through the light control section 30 without being totally reflected at the interface between the first light-transmitting section 32 and the low refractive index layer 33, and will reach the ceiling or the like on the rear side, causing reflections of the projected image, which is not desirable.

In addition, when the angle θ4 is smaller than this range, the external light to be transmitted through the screen 10 (for example, external light G1, G2, etc. shown in FIG. 5 described later) may be totally reflected at the interface between the first light transmitting portion 32 and the low refractive index layer 33 and the interface between the low refractive index layer 33 and the second light transmitting portion 34, and the transparency of the screen may decrease. In addition, when the angle θ4 is smaller than this range, the arrangement pitch P2 of the diffusion portion 35 becomes smaller, and as a result, the ratio of the area occupied by the diffusion portion 35 to the surface on the back side of the light control portion 30 (the surface formed by the second light transmitting portion 34 and the diffusion portion 35) becomes larger, and the transparency of the screen 10 (light control portion 30) may decrease. In addition, when the angle θ4 is smaller than this range, the arrangement pitch P2 of the diffusion portion 35 becomes smaller, and the diffraction phenomenon due to the light transmitted through the light control portion 30 is likely to occur. For the above reasons, it is not preferable that the angle θ4 is smaller than this range.
The angle θ4 may change continuously or stepwise in the arrangement direction of the low refractive index layers 33 (arrangement direction of the diffusion sections 35, Y direction) depending on the incident angle of the image light to the screen 10, the refractive index of each layer, etc. For ease of understanding, Fig. 2 and Fig. 4 show an example in which the angle θ4 is constant in the arrangement direction of the low refractive index layers 33 (vertical direction of the screen, Y direction).

The low refractive index layer 33 is formed by vapor deposition of SiO _2. When SiO ₂ is used, the refractive index of the low refractive index layer 33 is, for example, not less than 1.44 and not more than 1.46.
However, the present invention is not limited to this, and the low refractive index layer 33 may be formed from, for example, a resin that satisfies the condition of having high light transmittance and a refractive index lower than the first light transmitting portion 32 and the second light transmitting portion 34, or a fluorine compound such as magnesium fluoride. The method for forming the low refractive index layer 33 may be appropriately selected depending on the material used, and for example, the low refractive index layer 33 may be formed by a dip coating method, a spray method, CVD (Chemical Vapor Deposition), or the like, other than the deposition method.

As shown in FIG. 4, the second light transmitting portions 34 are provided at positions facing the second surface 32b of the first light transmitting portions 32 via the low refractive index layer 33, and are arranged along the screen surface.
4 is a triangular shape that is convex toward the image source side (+Z side). The second light transmitting portions 34 of the present embodiment are formed in a band shape such that their cross-sectional shape extends in the left-right direction of the screen (X direction), and are arranged in the up-down direction of the screen (Y direction) that intersects with the extending direction.

The second light transmitting portion 34 has a first surface 34a located on the lower side (-Y side) of the vertex t4, a second surface 34b located on the upper side (+Y side), and a third surface 43c located on the back side (-Z side).
The second surface 34b faces the second surface 32b of the first light transmitting portion 32 via the low refractive index layer 33, and the third surface 34c is parallel to the screen surface.
The second light transmitting portion 34 may have a continuous portion that is continuous with the XY plane between the convex shapes of adjacent second light transmitting portions 34 at the rear side end portion.

The second light transmitting portion 34 can be formed using an ultraviolet curing resin, an ionizing radiation curing resin, or a thermoplastic resin similar to the resin forming the above-mentioned first light transmitting portion 32. In addition, it is preferable that the second light transmitting portion 34 has the same refractive index as the first light transmitting portion 32, or that the difference in refractive index between the second light transmitting portion 34 and the first light transmitting portion 32 is as small as possible, from the viewpoint of suppressing deviation of the image (transmitted image) observed through the light control unit 30. Therefore, like the first light transmitting portion 32, the second light transmitting portion 34 of this embodiment preferably has a refractive index of 1.54 or more.
Similar to the first light transmitting portion 32, the second light transmitting portion 34 of the present embodiment is formed of an ultraviolet curing urethane acrylate resin (refractive index n1=1.55).

The diffusion section 35 is a transmitted light suppression section that has the effect of diffusing at least a part of the light incident thereon and that has the function of reducing the amount of light in the straight-line direction by diffusing the light that enters thereon and travels straight through the interior and is transmitted therethrough. The diffusion sections 35 are arranged alternately in the vertical direction (Y direction) of the screen with the portions that are convex on the back side formed by the first light transmitting section 32, the low refractive index layer 33, and the second light transmitting section 34 (hereinafter, these are referred to as light transmitting sections).
The diffusing portion 35 has a cross-sectional shape shown in FIG. 4 that is continuous in the left-right direction of the screen (X direction), and extends in a band shape in the left-right direction of the screen.

The cross-sectional shape of the diffusion section 35 shown in Fig. 4 is a wedge shape. The wedge shape here refers to a shape that is wide at one end and gradually narrows toward the other end, and includes a triangular shape, a trapezoidal shape, etc. The cross-sectional shape of the diffusion section 35 shown in Fig. 4 is a trapezoid shape in which the width (dimension in the Y direction) on the image source side (+Z side) is smaller than the width (dimension in the Y direction) on the back side (-Z side), but is not limited to this, and the diffusion section 35 may be a triangular shape with the image source side as the apex.
In FIG. 4, the surface of the diffusion section 35 on the image source side is the first surface 35a, the upper surface is the second surface 35b, the lower surface is the third surface 35c, and the rear surface is the fourth surface 35d.

In this embodiment, the first surface 35a and the fourth surface 35d are parallel to the screen surface (XY plane). The second surface 35b and the third surface 35c form angles θ5 and θ3, respectively, with respect to the thickness direction (Z direction) of the light control unit 30 (screen 10). In this embodiment, the angle θ3 is equal to the angle θ5, and θ3=θ5 is satisfied. Therefore, the cross-sectional shape of the diffusion unit 35 in this embodiment shown in FIG. 4 is an isosceles trapezoid.
It is preferable that each of the angles θ3 and θ5 is equal to or greater than 0° and equal to or less than 5° from the viewpoint of easily and accurately manufacturing the diffusion section 35. It is preferable that the angles θ3 and θ5 are smaller (i.e., the second surfaces 35b and 35b are closer to being parallel to the thickness direction (Z direction) of the light control section 30 (screen 10)), because this increases the amount of external light (G1 and G2 shown in FIG. 5 to be described later) that transmits through the light control section 30 (screen 10) and improves the transparency of the screen 10.

The arrangement pitch of the diffusion sections 35 (arrangement pitch of the first light transmitting sections 32 and the second light transmitting sections 34) is P2. In the cross section shown in FIG. 4, the dimension of the first surface 35a of the diffusion section 35 in the vertical direction of the screen (Y direction) is W1, and the dimension of the fourth surface 35d is W2. Among the dimensions between adjacent diffusion sections 35 (dimensions of the light transmitting sections), the dimension between the ends on the image source side is W3, and the dimension between the ends on the rear side is W4. The height of the diffusion section 35 (dimension in the thickness direction of the screen 10) is h2.

The arrangement pitch P2 of the diffusion sections 35 is preferably 100 to 1000 μm, and more preferably 200 to 500 μm. By setting the arrangement pitch P2 in the above range, it is possible to effectively diffuse the image light transmitted through the screen section 20 while ensuring a sufficient amount of light transmitted through the light control section 30 (screen 10). In addition, by setting the arrangement pitch P2 in the above range, it is possible to suppress the diffraction phenomenon caused by the arrangement of the diffusion sections 35, and to make the diffusion sections 35 less visible to the viewer.

The diffusion portion 35 has a binder material 351 and a plurality of light diffusion materials 352 contained therein.
The binder material 351 is preferably a resin material having optical transparency, and examples of the resin that can be used include transparent resins whose main components are one or more of acrylic, styrene, polycarbonate, polyethylene terephthalate, acrylonitrile, etc., and ionizing radiation curable resins such as ultraviolet curable resins such as epoxy acrylate and urethane acrylate.
The light diffusing material 352 is a particulate material that has optical transparency and has a refractive index different from that of the binder material 351. As the light diffusing material 352, crosslinked particles obtained by polymerizing monomers mainly consisting of (meth)acrylic acid ester and styrene, urethane crosslinked particles, or the like can be used.

The refractive index of the light diffusing material 352 has a difference from the refractive index of the binder material 351 .
From the viewpoint of obtaining a suitable diffusion effect, the refractive index difference (absolute value) between the light diffusion material 352 and the binder material 351 is preferably 0.02 or more and 0.2 or less, and more preferably 0.02 or more and 0.06 or less. If the refractive index difference is larger than this range, the diffusion effect by the diffusion section 35 becomes too strong, which is undesirable because it causes blurring and a decrease in contrast of the scenery (transmitted image) observed through the screen 10, and a decrease in the contrast of the image displayed on the screen 10. Also, if the refractive index difference is smaller than this range, the diffusion effect by the diffusion section 35 is too weak, and the image light transmitted through the screen section 20 and incident on the diffusion section 35 of the light control section 30 is not sufficiently diffused, resulting in a problem that the image is reflected on an object or ceiling on the back side of the screen 10.

Moreover, it is preferable that the refractive index of the light diffusion material 352 is lower than that of the binder material 351. As a result, most of the light incident on the light diffusion material 352 of the diffusion section 35 is refracted at the interface between the binder material 351 and the light diffusion material 352, and is suitably diffused by such refraction.
However, the refractive index of the light diffusion material 352 may be higher than that of the binder material 351. In this case, the amount of light that travels toward the image source side (+Z side) among the image light that is incident on the diffusion section 35 and diffused is larger than when the refractive index of the light diffusion material 352 is lower than that of the binder material 351. For this reason, it is preferable to appropriately adjust the content of the light diffusion material 352 and the difference in refractive index between the binder material 351 and the light diffusion material 352.

The light diffusing material 352 is preferably spherical, but may be of other shapes, such as an elliptical sphere. The average particle size r of the light diffusing material 352 is preferably 1 μm or more and is equal to or less than the width W1 of the first surface 35a, which is the image source side end of the diffusion section 35, from the viewpoint of favorably diffusing the light incident on the diffusion section 35 and sufficiently filling the diffusion section 35. In this embodiment, the light diffusing material 352 is spherical and has an average particle size of about 5 μm. In this embodiment, the width W1 of the first surface 35a is 8 μm, and the average particle size r of the light diffusing material 352 is smaller than the width W1 of the first surface 35a.
In addition, it is preferable that the ratio W1/r of the average particle size r of the light diffusing material 352 to the width W1 of the first surface 35a of the diffusion section 35 be 1 or more and 5 or less, from the viewpoint of sufficiently filling the diffusion section 35 with the light diffusing material 352.
In this case, the width W1 of the first surface 35a of the diffusion portion 35 is larger than the average particle diameter r of the light diffusion material 352, and is preferably 3 μm or more and 20 μm or less.

When the total weight of the diffusion section 35 is taken as 100 parts by weight, the amount of the light diffusion material 352 contained in the diffusion section 35 is preferably 10 parts by weight or more and 30 parts by weight or less from the viewpoint of obtaining a sufficient diffusion effect. Within this range, the amount of the light diffusion material 352 can be adjusted according to the refractive index difference between the binder material 351 and the light diffusion material 352. If the content of the light diffusion material 352 in the diffusion section 35 is less than the above range, it is difficult to obtain a sufficient diffusion effect, and if it is more than the above range, the diffusion effect becomes too large, which is not preferable.

The second base layer 36 is a layer located on the rear side of the light control section 30, has optical transparency, and has a function of protecting the diffusion section 35 and the second light transmission section 34.
The second base layer 36 can be made of the same material as the first base layer 21 of the screen portion 20, similar to the first base layer 31 described above.

By configuring the light control unit 30 as described above, a portion of the image light Lt that has passed through the screen unit 20 can be made to enter the first light transmitting unit 32 as shown in FIG. 4, where it is totally reflected at the interface with the low refractive index layer 33, and can be made to efficiently enter the diffusion unit 35. The image light Lt is then diffused by the diffusion unit 35 and emitted to the rear side. This makes it possible to reduce the reflection of the projected image on the ceiling or objects located on the rear side of the screen 10 due to the image light that has passed through the screen 10.

5 is a diagram for explaining how light entering the screen 10 of the present embodiment travels. The cross section of the screen 10 shown in Fig. 5 is similar to the cross section of the screen 10 shown in Fig. 2 described above.
The image light L1 projected from the image source LS located below the screen 10 enters the screen 10, passes through the first base layer 21 and the lens layer 22, and enters the reflective layer 23 formed on the lens surface 221a of the unit lens 221. A part of the image light L2 is diffusely reflected by the reflective layer 23 and exits to the observer O on the image source side. This allows the observer O to view an image formed by the image light projected onto the screen 10.

Of the image light L1 incident on the lens surface 121a, the remaining image light L3 that is not reflected by the reflective layer 23 passes through the reflective layer 23, the planarizing layer 24, the second base material layer 25, and the bonding layer 40, and enters the light control unit 30.
The image light L3 incident on the light control unit 30 is transmitted through the first base material layer 31 and the first light transmitting unit 32, and is incident on the second surface 32b of the first light transmitting unit 32. The second surface 32b is the interface between the first light transmitting unit 32 and the low refractive index layer 33, and the image light L3 is incident on the second surface 32b at an angle equal to or greater than the critical angle and is totally reflected. The image light L3 then enters the diffusion unit 35 and is diffused, and is transmitted through the second base material layer 36 to be emitted to the rear side (-Z side) of the screen 10.
At this time, the image light L3 is diffused by the diffusion section 35, and the reflection of the projected image onto objects and persons O2 on the rear side and onto the ceiling is significantly suppressed.

Next, light from the outside world such as sunlight (hereinafter referred to as outside light) other than the image light that enters the screen 10 from the rear side (−Z side) or the image source side (+Z side) will be described.
External light G1 incident on the screen 10 at a small angle of incidence from the image source side is partly reflected by the reflective layer 23 of the screen unit 20, but most of it passes through the reflective layer 23 to enter the light control unit 30 and is incident at an angle smaller than the critical angle with respect to the interface (second surface 32b) between the first light transmitting unit 32 and the low refractive index layer 33. Therefore, most of the external light G1 is refracted at the interface, passes through the low refractive index layer 33 and the second base material layer 36, and is emitted to the back side of the screen 10.

Similarly, external light G2 incident on the screen 10 from the back side at a small angle of incidence passes through the second base material layer 36 and the second light transmitting portion 34, and is incident on the interface (second surface 34b) between the second light transmitting portion 34 and the low refractive index layer 33 at an angle smaller than the critical angle. Therefore, most of the external light G2 is refracted at the interface, passes through the low refractive index layer 33, and enters the screen portion 20. Then, although part of the external light G2 is reflected by the reflective layer 23, most of it passes through the reflective layer 23 and is emitted to the image source side of the screen 10.
The screen portion 20 does not contain a diffusion material containing diffusion particles, and most of the external light G1, G2 does not enter the diffusion portion 35, so most of the external light G1, G2 passes through the screen 10 without being diffused.

Further, a part of the external light (not shown) that is incident on the screen at a small angle of incidence, such as the external light G1 and G2, enters the diffusion section 35 and is diffused and transmitted through the screen 10, but the amount of the light is small.
Therefore, the screen 10 of this embodiment has a transparency that allows an observer O on the image source side of the screen 10 and an observer O2 on the back side to clearly see the scenery on the other side (transmitted image) through the screen 10. Furthermore, the screen 10 of this embodiment can prevent the scenery on the other side (transmitted image) observed through the screen 10 from appearing blurred or whitish, and can also prevent a decrease in image contrast caused by external light, etc.

5, of the external light G3 incident on the screen 10 from above on the image source side, a portion of the external light G4 is reflected by the reflective layer 23 and emitted downward on the image source side of the screen 10, or is totally reflected on the surface on the image source side (+Z side) of the screen 10 and attenuated toward the bottom inside the screen 10. Therefore, such external light G4 does not reach the observer O, and the screen 10 can suppress a decrease in contrast of the image.
Furthermore, a portion of the external light G3, external light G5, passes through the reflective layer 23, enters the light control unit 30 on the rear side, enters the interface (second surface 32b) between the first light transmitting unit 32 and the low refractive index layer 33 at an angle smaller than the critical angle, passes through the low refractive index layer 33, the second light transmitting unit 34, and the second base material layer 36, and exits downward on the rear side of the screen 10. Although not shown, a portion of the external light G5 enters the diffusion unit 35, is diffused, and exits downward on the rear side of the screen 10. Therefore, the screen 10 can prevent such external light G5 from reaching the observer O2 on the rear side, thereby reducing the transparency of the screen 10 and reducing the contrast of the image.

Of the external light incident from above the rear side of the screen 10, a portion of the external light (not shown) passes through the second base layer 36 and the second light-transmitting section 34, enters the diffusion section 35 and is diffused there; however, the amount of such external light is small, and the light intensity is reduced by being diffused by the diffusion section 35. This makes it possible to suppress a decrease in the contrast of the image displayed on the screen of the screen 10 and the transmitted image observed through the screen 10, and maintain the transparency of the screen 10.

According to this embodiment, the screen 10 is transparent and has a light control unit 30 on the rear side (-Z side) of the screen section 20 which has a semi-transmissive reflective layer 23, so that the image light transmitted through the reflective layer 23 can be diffused by the diffusion unit 35 and emitted to the rear side, and the image can be significantly prevented from being reflected on the ceiling on the rear side or on objects or people located on the rear side. This can improve the design and comfort of the space in which the image display device 1 is placed.

In addition, according to this embodiment, a low-refractive index layer 33 having a lower refractive index than the first light-transmitting portion 32 and the second light-transmitting portion 34 is formed between adjacent diffusion portions 35, and the interface (second surface 32b) between the first light-transmitting portion 32 and the low-refractive index layer 33 forms an angle θ4 with respect to the thickness direction of the screen 10, and the image light that passes through the reflective layer 23 of the screen portion 20 and enters the light control portion 30 is incident on the interface at an angle equal to or greater than the critical angle, forming a total reflection surface that is totally reflected. As a result, the image light that passes through the reflective layer 23 and, if the low-refractive index layer 33 is not provided, is emitted to the back side of the screen 10, causing the projection image to be reflected on the ceiling, etc., can be more effectively diffused by being incident on the diffusion portion 35, and the effect of suppressing the image from being reflected on the ceiling on the back side or on objects or people located on the back side can be significantly improved.

In addition, by providing a low refractive index layer 33 between adjacent diffusion sections 35, the arrangement pitch P2 of the diffusion sections 35 can be widened. This suppresses the diffraction phenomenon that is likely to occur when the arrangement pitch P2 is small, and suppresses blurring of the transmitted image when looking through the screen 10. This also makes it possible to reduce the thickness of the light control section 30 while maintaining its optical performance.

(Modifications)
The present invention is not limited to the above-described embodiment, and various modifications and variations are possible, and these are also within the scope of the present invention.
(1) In the embodiment, an example is shown in which the screen unit 20 has a lens layer 22, and the reflective layer 23 is formed on the lens surface 221a and the non-lens surface 221b. However, this is not limited to the above. For example, the screen unit 20 may not have the lens layer 22, and the reflective layer 23 may be formed on a planar resin layer having a fine uneven shape.
In addition, in the embodiment, the lens layer 22 may have a linear Fresnel lens shape on the rear surface side, and may have an arrangement of unit prism shapes instead of the unit lenses 221 .

(2) In the embodiment, the diffusion section 35 has an isosceles trapezoidal cross-sectional shape in a cross section parallel to the arrangement direction (Y direction) of the first light transmitting sections 32 and the thickness direction (Z direction) of the light control section 30, but is not limited to this and may have an asymmetric trapezoidal shape in the arrangement direction. For example, in the arrangement direction (Y direction) of the diffusion section 35, one of the upper (+Y side) surface or the lower (-Y side) surface of the diffusion section 35 may have a trapezoidal shape parallel to the thickness direction (Z direction) of the light control section 30 (screen 10).
In addition, in the embodiment, the diffusion portion 35 may have a polygonal shape other than a trapezoidal shape, and may have a polygonal shape such as a rectangular shape or a pentagonal shape.
In addition, in the embodiment, the cross-sectional shape of the diffusion section 35 may be such that the first surface 35a on the image source side is inclined with respect to the arrangement direction (Y direction).
In the embodiment, the diffusion portion 35 may be formed partly with a curved surface, or partly with a folded surface.
In addition, at least one of the angles θ5, θ3 that the second surface 35b and the third surface 35c of the diffusion section 35 make with the thickness direction (Z direction) of the screen 10 (light control section 30) may change continuously or stepwise in the arrangement direction of the diffusion section 35.

(3) In the embodiment, an example was shown in which the arrangement pitch P2 of the diffusion section 35 is constant, but this is not limited to the above. For example, the arrangement pitch P2 may increase continuously or in stages as the distance from the image source LS increases in the arrangement direction (Y direction).
In addition, in the embodiment, an example has been shown in which the angle θ4 that the low refractive index layer 33 makes with the thickness direction of the screen 10 (light control unit 30) is constant, but this is not limited to this, and the angle may be increased continuously or stepwise in the arrangement direction (Y direction) of the low refractive index layer 33 as it moves away from the image source LS.

(4) In an embodiment, the low refractive index layer 33 may be an air layer.

(5) In the embodiment, the screen 10 may be configured such that the second base layer 25 and the bonding layer 40 of the screen portion 20 are not provided, and the light control portion 30 is laminated on the rear side of the planarization layer 24. By adopting such a configuration, it is possible to make the screen 10 thinner and reduce production costs.

(6) In the embodiment, a hard coat layer for the purpose of preventing scratches may be provided on the image source side (+Z side) of the screen 10. The hard coat layer is formed, for example, by applying an ultraviolet-curable resin (e.g., urethane acrylate) having a hard coat function to the image source side surface of the screen 10 (the image source side surface of the first base layer 21 of the screen unit 20).
Furthermore, in addition to the hard coat layer, one or more layers having appropriate functions such as anti-reflection function, ultraviolet absorbing function, anti-fouling function, anti-static function, etc. may be selected and provided depending on the usage environment and purpose of the screen 10. Furthermore, a touch panel layer or the like may be provided on the image source side (observer side) of the first base material layer 21 of the screen portion 20.
In addition, the layer having the above-mentioned functions may be laminated not only on the image source side surface of the screen 10 (the image source side surface of the first base material layer 21) but also on the rear side surface (the rear side surface of the second base material layer 36 of the light control unit 30).
A colored layer for achieving a predetermined amount of transmitted light or for improving the contrast of an image may be provided inside the screen 10. Such a colored layer is, for example, dark and transparent, such as black, and has the function of transmitting part of the incident light and absorbing part of it.

(7) In the embodiment, the screen unit 20 may not include the first base material layer 21 and the second base material layer 25, or may not include either one of them, when the lens layer 22 and the planarization layer 24 have sufficient thickness, rigidity, etc. Note that the light control unit 30 may also not include the first base material layer 31 and the second base material layer 36, or may not include either one of them, when the first light transmitting unit 32 and the second light transmitting unit 34 have sufficient thickness, rigidity, etc.
From the viewpoint of reducing interfacial reflection of light at the interfaces between layers, it is preferable that the screen 10 as a whole be configured without at least one of the second base layer 25 and the first base layer 31 .

In the embodiment, the screen 10 may have at least one of the first base material layer 21 and the second base material layer 25 of the screen section 20 and the first base material layer 31 and the second base material layer 36 of the light control section 30 as a plate-like member made of resin such as acrylic or a plate-like member having optical transparency such as a glass plate. In this case, the other layer may be bonded to the glass plate or the like via an adhesive layer or the like. For example, the screen 10 may have a form in which the screen section 20 does not have the second base material layer 25 and the light control section 30 does not have the first base material layer 31, and the screen section 20 and the light control section 30 are bonded to both sides of a transparent substrate. Examples of such transparent substrates include a plate-like member made of resin with high transparency and a glass plate.

(8) In the embodiment, an example has been shown in which the lens surface 221a and the non-lens surface 221b of the unit lens 221 are formed by flat surfaces. However, this is not limited to this. For example, the unit lens 221 may have a shape in which a curved surface and a flat surface are combined, or may have a folded surface.
In addition, in the embodiment, the unit lens 221 may have a polygonal shape formed by three or more surfaces.
In the embodiment, the reflective layer 23 is formed on the lens surface 221a and the non-lens surface 221b. However, the present invention is not limited to this. For example, the reflective layer 23 may be formed on at least a part of the lens surface 221a.
In the embodiment, the lens surface 221a and the non-lens surface 221b are rough surfaces having fine irregularities formed thereon. However, the present invention is not limited to this, and only the lens surface 221a may be a rough surface.

(9) In the embodiment, the image display device 1 is arranged in a show window of a store or the like, but the present invention is not limited to this. For example, the image display device 1 can be used as an indoor partition or for displaying images at an exhibition or the like. The image display device 1 can also be used in a vehicle such as a car or a ship, with the screen 10 attached to the window glass, an internal partition, or the like.

(10) In the embodiment, the transmitted light suppression section (diffusion section 35) may be configured to further contain a coloring material of a dark color such as black or gray in addition to the light diffusion material 352. By configuring in this manner, it is possible to absorb a part of the transmitted image light to reduce the reflection of the projected image on a person or object located on the rear side of the screen 10, or to absorb external light from the rear side to improve the contrast of the image displayed on the screen 10.
Furthermore, in the embodiment, the light control unit 30 may include a light shielding unit having a light shielding function at the position of the diffusion unit 35 shown in the embodiment as the transmitted light suppression unit. The light shielding unit is filled with a light absorbing material, pigment, dye, etc. having a dark color such as black light absorption property. By forming the light control unit 30 in this form, most of the transmitted image light can be reflected by the total reflection surface and efficiently absorbed by the light shielding unit, and the effect of reducing the reflection of the projected image on a person or object located on the back side of the screen 10 and absorbing external light from the back side to improve the contrast of the image displayed on the screen can be further enhanced. Furthermore, by forming such a light control unit, compared to the light control member having a diffusion unit as the transmitted light suppression unit shown in the embodiment, the function of suppressing the transmission of the image light can be maintained even if the arrangement pitch of the transmitted light suppression unit is widened, and the diffraction phenomenon can be reduced.

(11) In the embodiment, the image source LS is disposed below (on the -Y side) the screen 10 in the vertical direction (Y direction), but the present invention is not limited to this. For example, the image source LS may be disposed above (on the +Y side) the screen 10 in the vertical direction. In this case, the position of the image source LS in the vertical direction corresponds to the position of point C that is the Fresnel center, and the screen 10 is used with its up-down direction inverted.
Moreover, the image source LS may be located on the right or left side of the screen 10 in the horizontal direction (X direction). In this case as well, the position of the image source LS is made to correspond to the position of point C, which is the Fresnel center, in the horizontal direction, and the screen 10 is used with its up-down direction rotated 90° to the left or right.

The present embodiment and its variations can be used in appropriate combinations, but detailed explanations will be omitted. Furthermore, the present invention is not limited to the above-described embodiments.

REFERENCE SIGNS LIST 1 image display device 10 screen 20 screen portion 21 first base layer 22 lens layer 22
Reference Signs List 221 unit lens 23 reflective layer 24 planarizing layer 25 second base layer 30 light control section 31 first base layer 32 first light transmitting section 33 low refractive index layer 34 second light transmitting section 35 diffusion section 351 binder material 352 light diffusion material 40 bonding layer LS image source

Claims (10)

A reflective screen that displays an image by reflecting a portion of projected image light,
a screen section including a semi-transmissive reflective layer having an uneven surface that reflects a portion of incident light, transmits a portion of incident light, and diffuses the light, and which reflects a portion of the projected image light to display the image;
a sheet-like light control member that is disposed on a rear side of the screen unit, the rear side being opposite to the image source side in a thickness direction of the screen unit, and that has at least one of a function of diffusing or blocking at least a part of light that is incident from a specific direction;
having
The light control member is
a transmitted light suppression unit having at least one of a function of diffusing or a function of blocking at least a part of incident light, having a predetermined dimension in a thickness direction of the light control member, and being arranged along a sheet surface of the light control member;
a light transmitting portion provided between adjacent transmitted light suppressing portions;
a low refractive index layer provided in the light transmitting portion and inclined to form a predetermined angle with respect to a thickness direction of the light control member, the low refractive index layer having a refractive index lower than that of the light transmitting portion;
Equipped with
The transmitted light suppression unit is
the light control member is formed in a strip shape so as to extend in a first direction along a sheet surface of the light control member, and is arranged in a second direction intersecting the first direction,
a cross-sectional shape in a cross section parallel to the second direction and a thickness direction of the light control member is wedge-shaped,
The light suppression unit has a function of at least one of diffusing and blocking light that is incident on the transmitted light suppression unit and travels straight through the unit to transmit therethrough, thereby reducing the amount of light in the straight-line direction;
an angle that the low refractive index layer makes with a thickness direction of the light control member is larger than an angle that the image light transmitted through the reflective layer makes with the thickness direction of the light control member in the light transmitting portion;
A reflective screen featuring: 2. The reflective screen according to claim 1,
In the thickness direction of the light control member, the portions of the light transmitting portion located on both sides of the low refractive index layer and in contact with the low refractive index layer have the same refractive index;
A reflective screen featuring: 3. The reflective screen according to claim 1,
the transmitted light suppression portion is made of a resin material having light transparency and containing a light diffusing material having a refractive index different from that of the resin material and having light transparency, and diffuses at least a part of the incident light;
A reflective screen featuring: 4. The reflective screen according to claim 3,
The refractive index of the light diffusing material is smaller than the refractive index of the resin material;
A reflective screen featuring: 5. The reflective screen according to claim 1,
the transmitted light suppression portion contains a light absorbing material that absorbs light and absorbs at least a portion of the incident light;
A reflective screen featuring: 6. The reflective screen according to claim 1,
The screen portion does not contain a diffusing material that diffuses light.
A reflective screen featuring: 7. The reflective screen according to claim 1,
The optical shape layer has a plurality of unit optical shapes arranged on a rear surface, the unit optical shapes having a first surface on which image light is incident and a second surface intersecting the first surface, and the unit optical shapes are arranged on a rear surface.
The reflective layer is formed on at least a first surface of the unit optical shape;
A reflective screen featuring: 8. The reflection type screen according to claim 7,
In a cross section passing through the center of the screen of the reflective screen and parallel to the arrangement direction of the unit optical shapes and the thickness direction of the reflective screen,
the first surface is inclined such that an upper end portion in a vertical direction of the screen when the reflective screen is in a used state is located closer to an image source in a thickness direction of the reflective screen than a lower end portion;
the low refractive index layer is inclined so that an upper end portion in the vertical direction of the screen when the reflective screen is in use is located closer to the rear side in the thickness direction of the reflective screen than a lower end portion;
A reflective screen featuring: 9. The reflective screen according to claim 1,
the low refractive index layer forms an angle of 30 to 80° with respect to the thickness direction of the reflective screen;
A reflective screen featuring: A reflective screen according to any one of claims 1 to 9,
an image source that projects image light onto the reflective screen;
A video display device comprising:

Images