JP7705607B2 - Transmissive screen and display system - Google Patents

Description

This disclosure relates to a transmissive screen and a display system.

Transmission screens are known, as disclosed in Patent Document 1. The transmission screen includes a light-entering side and a light-exiting side. An image light source projects image light onto the light-entering side of the transmission screen. The transmission screen diffuses and transmits the image light. The diffusion by the transmission screen allows an observer to observe an image on the light-exiting side.

JP 2016-18195 A

The translucent screen disclosed in Patent Document 1 has a light diffusion function that diffuses image light over its entire area. Therefore, external light other than the image light that enters the translucent screen is also diffused by the translucent screen. As a result, the contrast of the image is reduced due to the diffusion of external light. The present disclosure aims to improve the contrast of images displayed on a translucent screen.

The translucent screen according to one embodiment of the present disclosure comprises:
A translucent screen onto which image light is projected from an image light source,
The first and second portions are arranged alternately in a first direction,
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
a distance between the first surface and the second surface along the first direction is larger on the light exit side than on the light entrance side;
the second surface of the first portion is located on a second side closer to the image light source in the first direction, and the first surface of the first portion is located on a first side away from the image light source in the first direction;
The first portion includes a light diffusion portion having a light diffusion function,
A first angle between the first surface and the first direction may be greater than or equal to 40° and less than a second angle between the second surface and the first direction.

In a translucent screen according to an embodiment of the present disclosure, the first portion may include a light-shielding portion that constitutes the first surface, and the light-shielding portion may have visible light-shielding properties.

In a translucent screen according to one embodiment of the present disclosure, the first portion may include a light absorbing portion constituting the first surface, and the light absorbing portion may have visible light absorption properties.

In a translucent screen according to an embodiment of the present disclosure, the first portion may include a light reflecting portion located between the light absorbing portion and the light diffusing portion, and the light reflecting portion may have visible light reflectivity.

In a translucent screen according to one embodiment of the present disclosure, the first portion may include a light reflecting portion constituting the first surface, and the light reflecting portion may have visible light reflectivity.

In a translucent screen according to one embodiment of the present disclosure, the light reflecting portion may include a metal layer.

In a translucent screen according to one embodiment of the present disclosure, the refractive index of the portion constituting the second surface of the first portion may be higher than the refractive index of the second portion.

In a translucent screen according to an embodiment of the present disclosure,
The first portion may include a low refractive index portion that constitutes the first surface,
The refractive index of the low refractive index portion may be lower than the refractive index of a portion of the first portion adjacent to the low refractive index portion.

In a translucent screen according to an embodiment of the present disclosure,
The first portion may include a low refractive index portion that constitutes the first surface,
The refractive index of the low refractive index portion may be lower than the refractive index of the second portion.

In a translucent screen according to one embodiment of the present disclosure, the refractive index of the portion constituting the first surface of the first portion may be higher than the refractive index of the second portion.

In a translucent screen according to one embodiment of the present disclosure, the magnitude of the first angle may be greater than Arccos(1/n), where n is the refractive index of the second portion, and may be less than or equal to 80°.

In a translucent screen according to one embodiment of the present disclosure, the magnitude of the first angle of one first portion may be greater than the magnitude of the first angle of another first portion located on the first side in the first direction relative to the one first portion.

In a translucent screen according to one embodiment of the present disclosure, the magnitude of the first angle of any one of the first portions may be equal to or greater than the magnitude of the first angle of any other one of the first portions that is located on the first side in the first direction from the one of the first portions.

In a translucent screen according to one embodiment of the present disclosure, the magnitude of the second angle may be greater than or equal to 85° and less than or equal to 90°.

In a translucent screen according to an embodiment of the present disclosure,
a light control layer including the first portion and the second portion;
a light-shielding layer located on the light output side of the light control layer,
The light-shielding layer may have a visible light-shielding property,
The light-shielding layer may face a light-exiting side surface of the second portion from the light-exiting side.

In a translucent screen according to an embodiment of the present disclosure,
a light control layer including the first portion and the second portion;
a light absorbing layer located on the light output side of the light control layer,
The light absorbing layer may have visible light absorbing properties,
The light absorbing layer may face a light exiting side surface of the second portion from the light exiting side.

In a translucent screen according to an embodiment of the present disclosure,
a light control layer including the first portion and the second portion;
a light reflecting layer located on the light output side of the light control layer,
The light reflective layer may have visible light reflectivity,
The light reflecting layer may face a light exiting side surface of the second portion from the light exiting side.

In a translucent screen according to an embodiment of the present disclosure,
a light control layer including the first portion and the second portion;
A decorative layer is located on the light output side of the light control layer and displays a design.
The decorative layer may face a light-emitting side surface of the second portion from the light-emitting side.

In a translucent screen according to an embodiment of the present disclosure,
a light control layer including the first portion and the second portion;
a light-shielding layer located on the light output side of the light control layer,
The light-shielding layer may have a visible light-shielding property,
The light-shielding layer may face only a part of the light-emitting side surface of the second portion from the light-emitting side,
The portion may include an end portion on the first side in the first direction of the light output side surface and may be spaced apart from an end portion on the second side in the first direction of the light output side surface.

In a translucent screen according to an embodiment of the present disclosure,
a light control layer including the first portion and the second portion;
a light absorbing layer located on the light output side of the light control layer,
The light absorbing layer may have visible light absorbing properties,
The light absorbing layer may face only a part of the light output side surface of the second portion from the light output side,
The portion may include an end portion on the first side in the first direction of the light output side surface and may be spaced from an end portion on the second side in the first direction of the light output side surface.

In a translucent screen according to an embodiment of the present disclosure,
a light control layer including the first portion and the second portion;
a light reflecting layer located on the light output side of the light control layer,
The light reflective layer may have visible light reflectivity,
The light reflecting layer may face only a part of the light exiting side surface of the second portion from the light exiting side,
The portion may include an end portion on the first side in the first direction of the light output side surface and may be spaced from an end portion on the second side in the first direction of the light output side surface.

The translucent screen according to one embodiment of the present disclosure comprises:
The first and second portions are arranged alternately in a first direction,
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
The first portion includes a light diffusing portion having a light diffusing function and a light blocking portion that constitutes the first surface,
The light-shielding portion may have a visible light-shielding property, and a first angle between the first surface and the first direction may be less than a second angle between the second surface and the first direction.

The translucent screen according to one embodiment of the present disclosure comprises:
The first and second portions are arranged alternately in a first direction,
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
The first portion includes a light diffusing portion having a light diffusing function and a light absorbing portion constituting the first surface,
The light absorbing portion has visible light absorbing properties,
A first angle between the first plane and the first direction may be less than a second angle between the second plane and the first direction.

The translucent screen according to one embodiment of the present disclosure comprises:
The first and second portions are arranged alternately in a first direction,
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
The first portion includes a light diffusing portion having a light diffusing function and a light reflecting portion constituting the first surface,
The light reflecting portion has visible light reflectivity,
A first angle between the first plane and the first direction may be less than a second angle between the second plane and the first direction.

The translucent screen according to one embodiment of the present disclosure comprises:
The first and second portions are arranged alternately in a first direction,
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
The first portion includes a light diffusion portion having a light diffusion function and a low refractive index portion constituting the first surface,
a first angle between the first plane and the first direction is less than a second angle between the second plane and the first direction;
The refractive index of the low refractive index portion may be lower than the refractive index of a portion of the first portion adjacent to the low refractive index portion.

The translucent screen according to one embodiment of the present disclosure comprises:
The first and second portions are arranged alternately in a first direction,
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
The first portion includes a light diffusion portion having a light diffusion function and a low refractive index portion constituting the first surface,
a first angle between the first plane and the first direction is less than a second angle between the second plane and the first direction;
The refractive index of the low refractive index portion may be lower than the refractive index of the second portion.

The translucent screen according to one embodiment of the present disclosure comprises:
The first and second portions are arranged alternately in a first direction,
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
The first portion includes a light diffusion portion having a light diffusion function,
a first angle between the first plane and the first direction is less than a second angle between the second plane and the first direction;
The refractive index of a portion of the first portion constituting the first surface may be higher than the refractive index of the second portion.

A display system according to an embodiment of the present disclosure includes:
Any of the translucent screens according to an embodiment of the present disclosure;
An image light source that projects image light onto the translucent screen may also be included.

The present invention can improve the contrast of images displayed on a translucent screen.

FIG. 1 is a diagram for explaining an embodiment of the present invention, and is a perspective view showing a display system and a translucent screen. FIG. 2 is a side view of the display system and translucent screen of FIG. FIG. 3 is a vertical sectional view showing an example of the translucent screen of FIG. 1 and FIG. FIG. 4A is a view corresponding to FIG. 3 and is a vertical sectional view showing another example of the translucent screen of FIGS. 1 and 2. FIG. FIG. 4B is a view corresponding to FIG. 3 and is a vertical sectional view showing still another example of the translucent screen of FIGS. 1 and 2. In FIG. FIG. 5 is a side view showing still another example of the translucent screen of FIG. 1 and FIG. FIG. 6 is a plan view showing an example of a light control layer included in the transmissive screen of FIGS. FIG. 7 is a plan view corresponding to FIG. 6 and showing another example of the light control layer. FIG. 8 is a vertical cross-sectional view showing a specific example of the light control layer in the basic embodiment. FIG. 9 is a vertical cross-sectional view showing a modification of the first portion that can be included in the light control layer of FIG. FIG. 10 is a vertical cross-sectional view for explaining the function of the light control layer. FIG. 11 is a vertical cross-sectional view showing a modified example of the light control layer. FIG. 12A is a vertical cross-sectional view showing a modified example of the light control layer. FIG. 12B is a vertical cross-sectional view showing a modified example of the light control layer. FIG. 13A is a vertical sectional view showing a modified example of a translucent screen. FIG. 13B is a vertical sectional view showing a modified example of the translucent screen. FIG. 14A is a vertical sectional view showing a modified example of a translucent screen. FIG. 14B is a vertical sectional view showing a modified example of the translucent screen. FIG. 15 is a vertical sectional view showing a modified example of the translucent screen. FIG. 16 is a vertical sectional view showing a modified example of the translucent screen. FIG. 17A is a vertical cross-sectional view showing a specific example of a light control layer in the first modified embodiment. FIG. 17B is a vertical cross-sectional view showing a modified example of the light control layer. FIG. 17C is a vertical sectional view showing a modified example of the translucent screen. FIG. 18A is a vertical cross-sectional view showing another specific example of the light control layer in the first modified embodiment. FIG. 18B is a vertical cross-sectional view showing a modified example of the light control layer. FIG. 18C is a vertical sectional view showing a modified example of the translucent screen. FIG. 19 is a vertical sectional view showing still another example of the light control layer in the first modified embodiment. FIG. 20 is a vertical cross-sectional view showing a specific example of the light control layer in the second modified embodiment.

An embodiment of the present disclosure will be described below with reference to the drawings. In the drawings attached to this specification, the scale and aspect ratios have been appropriately altered and exaggerated from those of the actual objects for the convenience of illustration and ease of understanding. Furthermore, configurations shown in some drawings may be omitted in other drawings.

In this specification, terms that specify shapes and geometric conditions and their degrees, such as "parallel," "orthogonal," and "same," as well as values of lengths and angles, are not limited to their strict meanings, but are interpreted to include the range in which similar functions can be expected.

In this specification, the normal direction of a sheet-like (sheet-like, plate-like) member refers to the normal direction to the sheet surface of the target sheet-like (film-like, plate-like) member. The "sheet surface (film surface, plate surface)" refers to the surface that coincides with the planar direction of the target sheet-like (film-like, plate-like) member when the target sheet-like (film-like, plate-like) member is viewed overall and globally.

To clarify the directional relationships between the drawings, some drawings show the first direction D1, the second direction D2, and the third direction D3 as common directions using arrows with common symbols. As shown in FIG. 2, a symbol with an x in a circle indicates an arrow pointing into the paper in a direction perpendicular to the paper surface of the drawing. As shown in FIG. 6, a symbol with a dot in a circle indicates an arrow pointing outward from the paper in a direction perpendicular to the paper surface of the drawing. The tip of the arrow in the first direction D1 is the first side in the first direction, and the side opposite the first side in the first direction is the second side.

Figures 1 to 20 are diagrams for explaining one embodiment. Figures 1 and 2 are diagrams showing a display system 10. The display system 10 includes an image light source 15 and a translucent screen 20. The image light source 15 projects image light L11, L21 onto the translucent screen 20. The image light L11, L21 passes through the translucent screen 20. The image light L11, L21 is diffused by the translucent screen 20. An observer 9 can observe an image displayed on the translucent screen 20 from a direction within the diffusion range of the image light. In particular, the translucent screen 20 described in this embodiment is designed to improve the contrast of the displayed image.

The contrast is the brightness contrast. Contrast is evaluated as the ratio of the luminance when white is displayed in the presence of ambient light (white luminance) to the luminance when black is displayed in the presence of ambient light (black luminance). The higher this ratio, the better the contrast is evaluated to be.

The display system 10 and translucent screen 20 in one embodiment will be described below with reference to the illustrated specific example. First, the basic aspect of one embodiment will be described with reference to Figs. 1 to 16.

The image light source 15 projects image light. The image light is diffused by the translucent screen 20, and an image that can be observed by the observer 9 is displayed on the translucent screen 20. The image may be a moving image or a still image. The image may be composed of multiple colors or may be composed of a single color. The image light source 15 is not particularly limited. The image light source 15 can be applied in various formats. The image light source 15 may include a transmissive microdisplay or a reflective microdisplay as a spatial light modulator. An example of the transmissive microdisplay is a liquid crystal display panel. An example of the reflective microdisplay is a MEMS element such as a DMD (Digital Micromirror Device). The image light source 15 may include a laser light source as a light source that illuminates the spatial light modulator. The image light source 15 may include a laser light source and a scanning device that scans the light from the laser light source on the translucent screen 20.

In the illustrated example, a short-focus image light source 15 is used. The image light source 15 is disposed at a position that does not directly face the translucent screen 20. As shown in FIG. 6, when observed from the third direction D3, which is the normal direction of the translucent screen 20, the light source center 15C, which is the center of the emission surface of the image light source 15, is not located on the translucent screen 20. When projected in the third direction D3, which is the normal direction of the translucent screen 20, the light source center 15C does not overlap with the translucent screen 20. As shown in FIG. 2, the incident angle θa of the image light is greater than 0°. The incident angle θa is the smaller angle between the traveling direction of the light and the normal direction of the incident surface. The incident angle θa is 90° or less. The incident angle θa of the image light varies depending on the incident position on the translucent screen 20. In the illustrated example, the incident angle θa is in the range of 20° to 70°.

The image light is projected from the image light source 15 onto the translucent screen 20. The image light passes through the translucent screen 20. The translucent screen 20 diffuses the image light. The translucent screen 20 is sheet-shaped. The translucent screen 20 is of a transmissive type and includes a light-entering side surface 21 and a light-exiting side surface 22. The light-entering side surface 21 and the light-exiting side surface 22 form a pair of main surfaces of the sheet-shaped translucent screen 20.

The light-entering side 21 and the light-exiting side 22 face the third direction D3. The third direction D3 coincides with the normal direction of the translucent screen 20. In the illustrated example, the tip side of the arrow indicating the third direction D3 is the light-exiting side, and the side opposite the light-exiting side in the third direction D3 is the light-entering side.

In the illustrated example, the translucent screen 20 is flat. The translucent screen 20 may be curved. The illustrated translucent screen 20 extends in a first direction D1 and a second direction D2. The first direction D1 and the second direction D2 are perpendicular to each other. In the illustrated example, the third direction D3 is perpendicular to both the first direction D1 and the second direction D2. In the illustrated example, the translucent screen 20 has a rectangular shape when viewed from the third direction D3. The translucent screen 20 includes an edge extending in the first direction D1 and an edge extending in the second direction D2.

As shown in FIG. 3, the translucent screen 20 includes a light control layer 40. The light control layer 40 includes first portions 50 and second portions 60 arranged alternately in a first direction D1. The first portion 50 includes a first surface 51 and a second surface 52 that form an interface with the second portion 60. The first surface 51 and the second surface 52 face each other in the first direction D1. That is, the first surface 51 and the second surface 52 face each other in the first direction D1. The first portion 50 includes a light diffusion section 55 having a light diffusion function.

In the example shown in FIG. 3, the translucent screen 20 includes, in order from the light-entering side 21 toward the light-exiting side 22, a functional layer 35, a substrate 31, a bonding layer 33, a light control layer 40, and a functional layer 35. The functional layer 35, the substrate 31, and the bonding layer 33 may be omitted from the translucent screen 20. The translucent screen 20 may be a transparent screen that allows a view behind the translucent screen 20. When the translucent screen 20 is a transparent screen, the functional layer 35, the substrate 31, and the bonding layer 33 may be transparent to visible light.

"Having visible light transmittance" means that the visible light transmittance is greater than 30%, preferably 50% or more, and more preferably 80% or more. The visible light transmittance is determined as the average value of the total light transmittance at each wavelength when measured at an incident angle of 0° every 1 nm in the measurement wavelength range of 380 nm to 780 nm using a spectrophotometer (Shimadzu Corporation's "UV-3100PC", compliant with JIS K 0115).

The substrate 31 functions as a support for supporting the light control layer 40. The substrate 31 may be a glass plate. The glass plate may be soda lime glass. The substrate 31 may be a resin plate. The resin plate may be an acrylic resin plate or a polycarbonate plate. The substrate 31 may be window glass. The thickness of the substrate 31 may be, for example, 0.5 mm or more and 10 mm or less.

The bonding layer 33 bonds the light control layer 40 to the substrate 31. The bonding layer 33 may be formed using various adhesives or pressure-sensitive adhesives that are applied to optical members. The bonding layer 33 may bond the light control layer 40 so that it can be removed from the substrate 31. The bonding layer 33 may be capable of re-bonding the light control layer 40 removed from the substrate 31 to the substrate 31. For example, the position of the light control layer 40 relative to the substrate 31 may be changed depending on the position of the image light source 15. The bonding layer 33 may be made of a known pressure-sensitive adhesive, adhesive, photocurable resin, thermosetting resin, or the like. More specifically, the bonding layer 33 may be made of an acrylic pressure-sensitive adhesive that combines an acrylic copolymer and an isocyanate compound.

The functional layer is a layer expected to perform a specific function. One functional layer 35 may perform two or more functions. The functional layer is not particularly limited, but examples include a hard coat layer that exhibits scratch resistance, an antifouling layer that has an antifouling function, an antiglare layer that has an antiglare function, and an antireflection layer that has an antireflection function. In the example shown in FIG. 3, the functional layer 35 is a surface layer 36 that constitutes the surface of the translucent screen 20. The translucent screen 20 shown in FIG. 3 includes a first surface layer 36A that constitutes the light-entering side surface 21 and a second surface layer 36B that constitutes the light-exiting side surface 22.

3, the translucent screen 20 may constitute a window glass of a building. In the example shown in FIG. 3, the substrate 31 is disposed on the light-entering side of the light control layer 40. As shown in FIG. 4A, the substrate 31 may be disposed on the light-emitting side of the light control layer 40. In the example shown in FIG. 4A, the translucent screen 20 includes, in the order from the light-entering side surface 21 toward the light-emitting side surface 22, a functional layer 35, a light control layer 40, a bonding layer 33, a substrate 31, and a functional layer 35. The translucent screen 20 shown in FIG. 4A includes, as the functional layer 35, a first surface layer 36A located on the light-entering side and a second surface layer 36B located on the light-emitting side. In the example shown in FIG. 4A, the functional layer 35, the substrate 31, and the bonding layer 33 may be configured similarly to the functional layer 35, the substrate 31, and the bonding layer 33 of the translucent screen 20 shown in FIG. 3, respectively.

As shown in FIG. 4B, the substrate 31 may be disposed on both the light-entering side and the light-emitting side of the light control layer 40. In the example shown in FIG. 4B, the translucent screen 20 includes, in the order from the light-entering side surface 21 to the light-emitting side surface 22, a functional layer 35, a substrate 31, a bonding layer 33, a light control layer 40, a bonding layer 33, a substrate 31, and a functional layer 35. The translucent screen 20 includes, as the functional layer 35, a first surface layer 36A located on the light-entering side and a second surface layer 36B located on the light-emitting side. The translucent screen 20 includes, as the substrate 31, a first substrate 31A located on the light-entering side and a second substrate 31B located on the light-emitting side. The translucent screen 20 includes, as the bonding layer 33, a first bonding layer 33A located on the light-entering side and a second bonding layer 33B located on the light-emitting side. In the example shown in FIG. 4B, the functional layer 35, the substrate 31, and the bonding layer 33 may be configured similarly to the functional layer 35, the substrate 31, and the bonding layer 33 of the translucent screen 20 shown in FIG. 3. When the first substrate 31A and the second substrate 31B are glass plates, the translucent screen 20 constitutes a so-called laminated glass.

The transparent screen 20 may be rigid enough to be self-supporting. The transparent screen 20 may be flexible enough to be rolled up, as shown in FIG. 5. In the example shown in FIG. 5, the transparent screen 20 may be rolled up on a winding core 39 when not in use.

The light control layer 40 is in a sheet shape. The image light passes through the light control layer 40. The light control layer 40 includes a light entrance side 41 and a light exit side 42 based on the image light. The light entrance side 41 and the light exit side 42 form a pair of main surfaces of the sheet-shaped light control layer 40.

8, the light control layer 40 includes a plurality of first portions 50 arranged in the first direction D1. The first portions 50 include a light diffusion portion 55. The light diffusion portion 55 diffuses the incident light. The light diffusion portion 55 diffuses the image light L81. The light control layer 40 includes a plurality of second portions 60 arranged in the first direction D1. The second portions 60 have visible light transparency. The second portions 60 are the path of the image light L81 incident on the first portions 50. When the translucent screen 20 is a transparent screen, the second portions 60 are the transmission path of the backlight L82. As shown in FIG. 2 and FIG. 8, the backlight L22, L82 is light other than the image light L21, L81 traveling from the light incident side to the light exiting side. The transmission of the backlight L22, L82 allows the observer 9 to observe the background 7 through the translucent screen 20.

As shown in FIG. 8, the first portions 50 and the second portions 60 are alternately arranged in the first direction D1. The first portions 50 and the second portions 60 may extend linearly in a direction non-parallel to the first direction D1. As shown in FIG. 6, each first portion 50 may extend linearly in a second direction D2 perpendicular to the first direction D1. In the example shown in FIG. 6, each second portion 60 extends linearly in the second direction D2 perpendicular to the first direction D1. As shown in FIG. 7, the first portion 50 may extend curvedly. As shown in FIG. 7, the second portion 60 may extend curvedly. In the example shown in FIG. 7, the multiple first portions 50 extend along concentric circles. In the example shown in FIG. 7, the multiple second portions 60 extend along concentric circles. The multiple first portions 50 and the multiple second portions 60 may extend along concentric circles centered at the same position. When projected in the third direction D3, the center of the concentric circles overlaps with the light source center 15C, which is the center of the emission surface of the image light source 15.

The first direction D1 may be parallel to the vertical direction. The second direction D2 and the third direction D3 may be parallel to the horizontal direction.

8, the light control layer 40 may further include a sheet-shaped base portion (land portion) 48 in addition to the first portion 50 and the second portion 60. The base portion 48 supports the first portion 50 and the second portion 60. The base portion 48 is sheet-shaped. The base portion 48 may be integrally formed with the multiple second portions 60. The base portion 48 may be connected to the second portion 60 without a seam. In the example shown in FIG. 8, the base portion 48 and the second portion 60 constitute the light control layer main body 45. In other words, the light control layer 40 has a light control layer main body 45 in which multiple grooves 45a are formed, and first portions 50 formed in the multiple grooves 45a of the light control layer main body 45. The portions between the adjacent grooves 45a of the light control layer main body 45 constitute the second portion 60.

As shown in FIG. 8, the light control layer 40 may be bonded to a substrate 38. The translucent screen 20 may further include a substrate 38 bonded to the light control layer 40. In the example shown in FIG. 8, the substrate 38 is bonded to a base portion 48 of the light control layer body 45. The substrate 38 may be made of a polyethylene terephthalate film or a polycarbonate film having a thickness of 30 μm or more and 300 μm or less.

The base portion 48 and the substrate 38 are transparent to visible light. The base portion 48 and the substrate 38 serve as transmission paths for the image light L81 and the backlight L82. The base portion 48 and the substrate 38 are not essential components of the light control layer 40 and may be omitted.

Figure 8 shows the main cross section of the light control layer 40. The main cross section of the light control layer 40 is a cross section parallel to both the first direction D1, which is the arrangement direction of the first portion 50 and the second portion 60, and the third direction D3, which is the normal direction of the light control layer 40. The first portion 50 includes a first surface 51 and a second surface 52 that form an interface with the second portion 60. The first surface 51 and the second surface 52 face the first direction D1. In one first portion 50, the first surface 51 is located on a first side in the first direction D1, and the second surface 52 is located on a second side in the first direction D1. The first side is the side away from the image light source 15 in the first direction D1. The second side is the side approaching the image light source 15 in the first direction D1. The second side is the opposite side to the first side in the first direction D1. The distance D along the first direction D1 between the first surface 51 and the second surface 52 is longer on the light exit side in the third direction D3 than on the light entrance side in the third direction D3. In the illustrated example, the distance along the first direction D1 between the first surface 51 and the second surface 52 gradually increases from the light entrance side to the light exit side in the third direction D3.

The magnitude of the first angle θ1 between the first surface 51 and the first direction D1 is 40° or more. The magnitude of the first angle θ1 may be 45° or more, 60° or more, or 70° or more. The magnitude of the first angle θ1 is less than the magnitude of the second angle θ2 between the second surface 52 and the first direction D1. The magnitude of the first angle θ1 may be 85° or less, or 80° or less. The magnitude of the second angle θ2 may be 85° or more and 90° or less, or may be 90°. By setting the first angle θ1 and the second angle θ2 in this manner, the contrast of the image can be improved.

The first angle θ1 is the angle between the first surface 51 and the first direction D1, which are identified on the main cut surface of the light control layer 40. Two angles that total 180° are identified between the first surface 51 and the first direction D1 on the main cut surface. The first angle θ1 is the smaller of the two angles. The magnitude of the first angle θ1 is greater than 0° and less than or equal to 90°.

The second angle θ2 is the angle between the second surface 52 and the first direction D1, which are identified on the main cut surface of the light control layer 40. Two angles that total 180° are identified between the second surface 52 and the first direction D1 on the main cut surface. The second angle θ2 is the smaller of the two angles. The magnitude of the second angle θ2 is greater than 0° and less than or equal to 90°.

As described below, when the first surface 51 is a folded or curved surface, the first angle θ1 is determined at a position that is the center of the third direction D3 on the first surface 51. When the first surface 51 is a curved surface, the first angle is the angle between the tangent to the first surface 51 on the main cut surface of the light control layer 40 and the first direction D1. When the second surface 52 is a folded or curved surface, the second angle θ2 is determined at a position that is the center of the third direction D3 on the second surface 52. When the second surface 52 is a curved surface, the angle between the tangent to the second surface 52 on the main cut surface of the light control layer 40 and the first direction D1 is the second angle.

8, the first portion 50 includes a light-emitting side surface 54 in addition to the first surface 51 and the second surface 52. The light-emitting side surface 54 constitutes a part of the light-emitting side surface 42 of the light control layer 40. The first surface 51 is connected to the light-emitting side surface 54 on the light-emitting side in the third direction D3. The second surface 52 is connected to the light-emitting side surface 54 on the light-emitting side in the third direction D3. The first surface 51 and the second surface 52 are connected to each other on the light-entering side in the third direction D3. The illustrated first portion 50 has a triangular shape in the main cross section.

The first surface 51 and the second surface 52 may be inclined in opposite directions with respect to the third direction D3. As in the first portion 50A shown in FIG. 9, the first surface 51 and the second surface 52 may be inclined in the same direction with respect to the third direction D3.

As shown in FIG. 8, the first portions 50 may be disposed at equal intervals in the first direction D1. The first portions 50 may extend linearly without changing the cross-sectional shape. The multiple first portions 50 included in the light control layer 40 may be configured identically to each other.

The first surface 51 and the second surface 52 form an interface with the second portion 60. Therefore, the second portion 60 is adjacent to each of the two adjacent first portions 50 in the first direction D1. In accordance with the configuration of the first portions 50, in the illustrated example, the second portions 60 included in the light control layer 40 may be disposed at equal intervals along the first direction D1. The second portions 60 may extend linearly without changing the cross-sectional shape. The second portions 60 may be configured identically to each other.

The second portion 60 shown in FIG. 8 includes a light-entering side surface 61 and a light-exiting side surface 62. The second portion 60 is connected to the base portion 48 at the light-entering side surface 61. The light-exiting side surface 62 constitutes the light-exiting side surface 54 of the first portion 50 and the light-exiting side surface 42 of the light control layer 40. The light-exiting side surface 62 is parallel to the light-exiting side surface 54. The light-exiting side surface 62, together with the light-exiting side surface 54, forms the flat light-exiting side surface 42. The illustrated second portion 60 is trapezoidal in the main cross section. The trapezoid constituting the second portion 60 includes a wide lower base constituted by the light-exiting side surface 62 and a narrow upper base constituted by the light-entering side surface 61.

The dimensions of the main cut surface may be set as follows, for example. The arrangement pitch P of the first portion 50 along the first direction D1 may be 1 mm or less. The height H of the first portion 50 along the third direction D3 may be 1 mm or less. The thickness T of the light control layer 40 along the third direction D3 may be 100 μm or more and 2 mm or less. The aspect ratio of the first portion 50 may be greater than 1, may be 2 or more, or may be 5 or more. The aspect ratio of the first portion 50 is expressed as the ratio of the height H of the first portion 50 along the third direction D3 to the width W of the first portion 50 along the first direction D1, that is, H/W. The aspect ratio of the first portion 50 may be 10 or less, taking into account the stability of production.

The above specific configurations of the first part 50 and the second part 60 are merely examples. They can be modified as appropriate, taking into account the function of the translucent screen 20, which will be described later.

As shown in FIG. 9, the first portion 50 may include a light-entering side surface 53. The light-entering side surface 53 faces the light-exiting side surface 54 in the third direction D3. The light-entering side surface 53 may extend along the first direction D1. The light-entering side surface 53 may be connected to an end portion of the first surface 51 on the light-entering side. The light-entering side surface 53 may be connected to an end portion of the second surface 52 on the light-entering side. The first portion 50B may be trapezoidal in the main cross section.

The second surface 52 may be an uneven surface, as in the first portion 50C shown in FIG. 9. The second surface 52 as an uneven surface may have a light diffusion function that diffuses incident light. The first surface 51 may also be an uneven surface. The first surface 51 may be a flat surface, a curved surface, or a folded surface. The second surface 52 may be a flat surface, a curved surface, or a folded surface. The shapes and arrangements of the multiple first portions 50 included in the light control layer 40 may differ. The shapes and arrangements of the multiple second portions 60 included in the light control layer 40 may differ.

The first portion 50 is a light passage path. As shown in FIG. 8, the first portion 50 is mainly a passage path for the image light L81. The first portion 50 may be formed of a material having visible light transparency. As described above, the first portion 50 includes a light diffusion portion 55 at a position between the first surface 51 and the second surface 52. The light diffusion portion 55 diffuses the incident light. In particular, the light diffusion portion 55 is intended to diffuse the image light. The light diffusion portion 55 may be the second surface 52 as an uneven surface, as in the first portion 50C shown in FIG. 9. The light diffusion portion 55 may be the first surface 51 as an uneven surface.

As shown in FIG. 8, the light diffusion section 55 may include a base material section 55A and light diffusion elements 55B. The light diffusion elements 55B are dispersed within the base material section 55A. In the example shown in FIG. 8 etc., the first portion 50 is composed only of the light diffusion section 55. In this example, the light diffusion section 55 constitutes the entire area between the first surface 51 and the second surface 52. The material of the base material section 55A may be a resin. More specifically, the material of the base material section 55A may be an ionizing radiation curable resin that is cured by irradiation with ionizing radiation. Examples of the ionizing radiation curable resin include ultraviolet curable resin, electron beam curable resin, visible light curable resin, near infrared curable resin, etc. Examples of the resin material include acrylic resin. Examples of the light diffusion elements 55B include metal compounds, porous substances containing gas, resin beads that hold metal compounds around them, white fine particles, and even simple air bubbles.

In the illustrated example, the base portion 48 may be molded integrally with the second portion 60 using the same material as the second portion 60. An example of the material of the light control layer main body 45 including the second portion 60 and the base portion 48 is a resin material. More specifically, the material of the light control layer main body 45 including the second portion 60 and the base portion 48 may be an ionizing radiation curable resin that is cured by irradiation with ionizing radiation. Examples of the ionizing radiation curable resin include ultraviolet curable resin, electron beam curable resin, visible light curable resin, and near infrared curable resin. An example of the resin material is acrylic resin.

The light control layer 40 may be manufactured as follows. First, the light control layer main body 45 that constitutes the second portion 60 and the base portion 48 is manufactured. For example, a curable material (resin composition) such as epoxy acrylate that is cured by irradiation with ionizing radiation such as electron beams or ultraviolet rays may be used to manufacture the light control layer main body 45. A mold roll having a convex portion corresponding to the configuration (arrangement, shape, dimensions, etc.) of the groove 45a of the light control layer main body 45 is prepared. In other words, a mold roll having a concave portion corresponding to the configuration (arrangement, shape, dimensions, etc.) of the second portion 60 is prepared. A sheet that will form the substrate 38 is fed between the mold roll and the nip roll. In accordance with the feeding of the sheet, a curable material is supplied between the mold roll and the substrate 38. Thereafter, the curable material is pressed between the mold roll and the nip roll so that the uncured liquid curable material supplied on the substrate 38 is filled into the concave portion of the mold roll. At this time, the curable material is supplied onto the substrate 38 so that it is thicker than the depth of the recesses in the mold roll, i.e., so that the mold roll and the substrate 38 do not come into contact with each other. As a result, the above-mentioned base portion (land portion) 48 is formed from the curable material integrally with the second portion 60. After filling the space between the substrate 38 and the mold roll with uncured liquid curable material in this manner, the light is irradiated to cure (solidify) the curable material, thereby forming the light control layer main body 45.

Next, the first portion 50 may be produced using a resin composition that will form the first portion 50. This resin composition includes a curable resin material that forms the base material portion 55A by curing, and a light diffusion element 55B. Examples of the curable resin material that forms the base material portion 55A include a curable material such as urethane acrylate that is cured by ionizing radiation. First, a resin composition is supplied onto the light control layer main body 45 that has been formed previously. Then, the grooves 45a formed between the adjacent second portions 60, that is, the inside of the portions that correspond to the convex portions of the mold roll, are filled with the resin composition using a doctor blade. At this time, the excess resin composition that has overflowed outside the grooves 45a is scraped off by the doctor blade. Then, the resin composition between the second portions 60 is irradiated with ionizing radiation to cure it, thereby forming the first portion 50. As a result, a light control layer 40 having a base portion 48, and a first portion 50 and a second portion 60 provided on the base portion 48 is produced on the substrate 38.

Next, we will explain the operation of the display system 10 and the translucent screen 20 when they are in use.

As shown in Figures 1 and 2, image light L11, L21 is emitted from the image light source 15. The image light L11, L21 travels from the light-entering side 21 into the transmissive screen 20. The image light travels in the third direction D3 inside the transmissive screen 20 toward the light control layer 40. As shown in Figures 8 and 10, the image light L81, L101 passes through the light-entering side 41 and travels into the light control layer 40. The image light L81, L101 passes through the base portion 48 and travels from the light-entering side 61 into the second portion 60.

In FIG. 8, an example is shown in which image light L81 enters the substrate 38 and the light control layer 40 from the air layer. In FIG. 10, an example is shown in which image light L101 enters the light control layer 40 from the air layer.

2, the image light source 15 is located on the second side in the first direction D1. As shown in FIG. 2, the incident angle θa (°) of the image light to the transmissive screen 20 is large. As an example, the incident angle θa is 20° or more and 70° or less. Therefore, the image light traveling in the light control layer 40 travels from the second side to the first side in the first direction D1 from the light input side to the light output side in the third direction D3. As shown in FIG. 8 and FIG. 10, the image light L81, L101 traveling in the second portion 60 passes through the second surface 52 and travels into the first portion 50.

The first portion 50 includes a light diffusion section 55. The image light L81, L101 is diffused by the light diffusion section 55. The diffused image light L81, L101 passes through the light exiting side surface 42 and is emitted from the light control layer 40. As shown in FIG. 2, the diffused image light L81, L101 passes through the light exiting side surface 22 and is emitted from the translucent screen 20. The observer 9 can observe the image on the translucent screen 20 from various directions.

The image light that passes through the translucent screen 20 is diffused by the light diffusion section 55. Meanwhile, external light, such as ambient light in the environment in which the translucent screen 20 is installed, also enters the translucent screen 20. The external light can also be diffused by entering the light diffusion section 55. The contrast of the image displayed on the translucent screen 20 decreases as the external light is diffused.

On the other hand, in the embodiment described above, the distance D (see FIG. 8) between the first surface 51 and the second surface 52 of the first portion 50 along the first direction D1 is larger on the light exit side than on the light entrance side. The magnitude of the first angle θ1 between the first surface 51 and the first direction D1 is 40° or more and is less than the magnitude of the second angle θ2 between the second surface 52 and the first direction D1.

That is, the first surface 51 is inclined from the second side to the first side in the first direction D1 from the light-entering side to the light-emitting side in the third direction D3, which is the normal direction of the translucent screen 20. In the main cross section, the first surface 51 and the traveling direction of the image light L81, L101 are inclined to the same side with respect to the first direction D1. Therefore, the optical path length of the image light L81, L101 in the first part 50 including the optical diffusion section 55 can be secured to be long. By lengthening the optical path length of the image light L81, L101 in the first part 50, the image light L81, L101 can be efficiently diffused in the first part 50. For this reason, it is not necessary to provide the optical diffusion section 55 having strong optical diffusion properties over a wide range of the translucent screen 20. In this way, the diffusion of external light in the translucent screen 20 can be suppressed while efficiently diffusing the image light L81, L101. As a result, according to one embodiment, the contrast of the image displayed on the translucent screen 20 can be improved. Observer 9 can view high quality images.

In addition, because the magnitude of the second angle θ2 is greater than the magnitude of the first angle θ1, the image light L81, L101 can be efficiently diffused by the first portion 50, while the area of the first portion 50 can be reduced when the translucent screen 20 is observed from the third direction D3. Therefore, the backlight L82, L102 other than the image light L81, L101 that transmits through the translucent screen 20 from the light entrance side to the light exit side can be prevented from being diffused by the light diffusion section 55. This allows the observer 9 to observe a high-contrast image.

In the examples shown in Figures 8 and 10, the translucent screen 20 functions as a transparent screen. That is, the back of the translucent screen 20 can be seen through the translucent screen 20. The translucent screen 20 according to this embodiment can efficiently diffuse the image light and effectively suppress the diffusion of the backlight L82, L102. Therefore, the background 7 (see Figure 2) behind the translucent screen 20 can be clearly seen through the translucent screen 20. That is, the see-through property of the translucent screen 20 as a transparent screen can be improved.

However, the angle between the direction of travel of most of the image light traveling to the light diffusion section 55 and the first direction D1 tends to be within a predetermined angle range. As shown in FIG. 8, the angle θx (°) of the direction of travel of the light L83 incident on the translucent screen 20 at the maximum incident angle θa of 90° in the second portion 60 is Arccos(1/n), where n is the refractive index of the second portion 60. When the incident angle θa becomes smaller, the angle θx of the direction of travel in the second portion 60 becomes larger. From this point of view, the magnitude of the first angle θ1 may be larger than Arccos(1/n), where n is the refractive index of the second portion 60.

According to an example in which the magnitude of the first angle θ1 is greater than Arccos(1/n), the magnitude of the first angle θ1 is not too small and is sufficiently large with respect to the traveling direction angle θx between the traveling direction of the image light and the first direction D1. That is, the optical path length of the image light can be efficiently ensured while suppressing the size of the first portion 50 including the light diffusion portion 55. This makes it possible to efficiently diffuse the image light in the first portion 50 while reducing the area of the first portion 50 when the translucent screen 20 is observed from the third direction D3. Therefore, it is possible to more effectively suppress the diffusion of the backlight L82, L102 that transmits through the translucent screen 20 from the light input side to the light output side other than the image light by the light diffusion portion 55. As a result, the contrast of the image displayed on the translucent screen 20 can be further improved.

The first angle θ1 may be equal to or smaller than 80°. If the first angle θ1 is greater than 80°, the image light is more likely to pass through the first portion 50 in the first direction D1 without being diffused by the light diffusion section 55. Furthermore, if the first angle θ1 is greater than 80°, manufacturing difficulties arise.

The magnitude of the second angle θ2 may be 85° or more and 90° or less. According to this example, the area of the first portion 50 can be reduced when the translucent screen 20 is observed from the third direction D3D3. Therefore, the backlight L82, L102 that transmits through the translucent screen 20 from the light input side to the light output side other than the image light can be prevented from being diffused by the light diffusion section 55. This improves the contrast of the image displayed on the translucent screen 20. Also, the observer 9 can clearly observe the background 7 behind the translucent screen 20.

From the viewpoint of improving contrast, the refractive index of the portion constituting the first surface 51 of the first portion 50 may be greater than the refractive index of the second portion 60. As in the example shown in FIG. 8, when 55 including the base material portion 55A and the light diffusion element 55B constitutes the first surface 51, the refractive index of the base material portion 55A may be greater than the refractive index of the second portion 60.

In this example, the first surface 51 is an interface having a refractive index difference and functions as a reflective surface. As shown in FIG. 11, the image light L111 that is not diffused by the light diffusion section 55 of the first part 50 can be reflected by the first surface 51 and directed toward the light output side. This improves the efficiency of use of the image light from the image light source 15, allowing the image to be displayed brightly. As a result, the contrast of the image displayed on the translucent screen 20 can be improved.

In addition, the direction of light traveling through the light control layer 40 is inclined toward the same side as the first surface 51 with respect to the first direction D1. Therefore, the angle of incidence of the image light L111 that is not diffused by the light diffusion portion 55 of the first portion 50 on the first surface 51 becomes large. The refractive index of the portion that constitutes the first surface 51 of the first portion 50 is greater than that of the second portion 60. The refractive index of the base material portion 55A is greater than that of the second portion 60. Therefore, it is possible to make the reflection of the image light L111 on the first surface 51 a total reflection. Total reflection can greatly improve the efficiency of use of the image light from the image light source 15, allowing the image to be displayed brighter. As a result, the contrast displayed on the translucent screen 20 can be further improved.

In the embodiment described above, the translucent screen 20 is projected with image light from the image light source 15. The translucent screen 20 includes first portions 50 and second portions 60 arranged alternately in the first direction D1. The first portion 50 includes a first surface 51 and a second surface 52 that form an interface with the second portion 60. The first surface 51 and the second surface 52 face the first direction D1. The second surface 52 of the first portion 50 is located on a second side closer to the image light source 15 in the first direction D1. The first surface 51 of the first portion 50 is located on a first side away from the image light source 15 in the first direction D1. The first portion 50 includes a light diffusion portion 55 having a light diffusion function. The distance D along the first direction D1 between the first surface 51 and the second surface 52 is larger on the light exit side than on the light entrance side. The magnitude of the first angle θ1 between the first surface 51 and the first direction D1 is 40° or more and is less than the magnitude of the second angle θ2 between the second surface 52 and the first direction D1. According to this embodiment, the diffusion of external light can be suppressed while efficiently diffusing the image light. Therefore, the contrast of the image can be improved, and the image can be displayed brightly and clearly. In addition, since the diffusion of the backlight that transmits through the translucent screen 20 other than the image light can be suppressed, the background 7 behind the translucent screen 20 can be clearly seen through the translucent screen 20. In other words, the see-through property of the translucent screen 20 as a transparent screen can be improved.

In the embodiment described above, the translucent screen 20 includes the first portion 50 and the second portion 60 arranged alternately in the first direction D1. The first portion 50 includes a first surface 51 and a second surface 52 that form an interface with the second portion 60. The first surface 51 and the second surface 52 face the first direction D1. The first portion 50 includes a light diffusion portion 55 having a light diffusion function. The magnitude of the first angle θ1 between the first surface 51 and the first direction D1 is less than the magnitude of the second angle θ2 between the second surface 52 and the first direction D1. According to this embodiment, the first surface 51 is an interface having a refractive index difference and functions as a reflective surface. Therefore, the image light that is not diffused by the light diffusion portion 55 of the first portion 50 can be reflected by the first surface 51 and directed to the light output side. This improves the efficiency of use of the image light from the image light source 15, and the image can be displayed brightly. As a result, the contrast of the image displayed on the translucent screen 20 can be improved.

The basic aspect of one embodiment has been described with reference to specific examples, but the above-mentioned specific examples do not limit the basic aspect of one embodiment. The basic aspect of one embodiment described above can be embodied in various other specific examples, and various omissions, substitutions, modifications, additions, etc. can be made without departing from the spirit of the embodiment.

Below, an example of a variation on the basic embodiment will be described with reference to the drawings. In the following description and the drawings used in the following description, parts that can be configured similarly to the above-mentioned specific example will be designated by the same reference numerals as those used for the corresponding parts in the above-mentioned specific example, and duplicated descriptions will be omitted.

In the above-mentioned specific example, the magnitude of the first angle θ1 is adjusted according to the traveling direction angle θx between the traveling direction of the image light and the first direction D1. On the other hand, as shown in FIG. 12A and FIG. 12B, the incident angle θa of the image light L12A1, L12B1 to the translucent screen 20 changes according to the position of the translucent screen 20. With the change in the incident angle θa, the traveling direction angle θx of the image light also changes according to the position of the translucent screen 20. The incident angle θa and the traveling direction angle θx of the image light L12A1, L12B1 change according to the distance between the incident position on the translucent screen 20 and the image light source 15. If the distance between the incident position on the translucent screen 20 and the image light source 15 is long, the incident angle θa becomes large and the traveling direction angle θx becomes small. From the viewpoint of suppressing the size of the first portion 50 while ensuring the optical path length of the image light, when the traveling direction angle θx is large, the magnitude of the first angle θ may also be large. When the magnitude of the first angle θ is large, the area of the first portion 50 when observed from the third direction D3 is reduced, thereby suppressing the diffusion of the backlight.

Therefore, as shown in Figures 12A and 12B, the magnitude of the first angle θ1 of one first portion 50 may be smaller than the magnitude of another first angle θ1 located on the second side in the first direction D1 from the one first portion 50.
In other words, the magnitude of the first angle θ1 of one first portion 50 may be larger than the magnitude of another first angle θ1 located on the first side in the first direction D1 from the one first portion 50. Furthermore, the magnitude of the first angle θ1 of any one first portion 50 may be smaller than the magnitude of any other first angle θ1 located on the second side in the first direction D1 from the one first portion 50. In other words, the magnitude of the first angle θ1 of any one first portion 50 may be larger than the magnitude of any other first angle θ1 located on the 21st side in the first direction D1 from the one first portion 50.

According to these examples, the magnitude of the first angle θ1 can be appropriately set so as not to be too small relative to the traveling direction angle θx between the traveling direction of the image light and the first direction D1, depending on the position in the first direction D1. Therefore, the area of the first portion 50 when the translucent screen 20 is observed from the third direction D3 can be reduced. This makes it possible to more effectively prevent the backlight that transmits through the translucent screen 20 from the light input side to the light output side other than the image light from being diffused by the light diffusion section 55. As a result, the contrast of the image displayed on the translucent screen 20 can be improved. The see-through property of the translucent screen 20 as a transparent screen can be more effectively improved.

In the example shown in FIG. 12A, the length W of the first portion 50 along the first direction D1 is constant. In the example shown in FIG. 12A, the arrangement pitch P of the first portion 50 along the first direction D1 is constant. In the example shown in FIG. 12A, the length H of the first portion 50 along the third direction D3 varies. In the example shown in FIG. 12B, the length H of the first portion 50 along the third direction D3 is constant. In the example shown in FIG. 12B, the length W of the first portion 50 along the first direction D1 varies. In the example shown in FIG. 12B, the arrangement pitch P of the first portion 50 along the first direction D1 varies.

As another modified example, as shown in FIG. 13A and FIG. 13B, the transmissive screen 20 may include a light-shielding layer 65 located on the light-emitting side of the light control layer 40. The light-shielding layer 65 faces only a part of the light-emitting side surface 62 of the second portion 60 from the light-emitting side in the third direction D3. The part of the light-emitting side surface 62 facing the light-shielding layer 65 includes a first end 62a that is a first side of the light-emitting side surface 62 in the first direction D1, and is away from a second end 62b that is a second side of the light-emitting side surface 62 in the first direction D1. According to the light-shielding layer 65 that faces only a part of the light-emitting side surface 62, the image light L13A1, L13B1 that is not incident on the first portion 50 can be shielded by the light-shielding layer 65. The light-shielding layer 65 can shield the image light L13A1, L13B1 that is not diffused by the light diffusion portion 55. This makes it possible to suppress the image from being observed brightly from an unintended direction.

The light-shielding layer 65 has visible light-shielding properties. "Having visible light-shielding properties" means that the visible light transmittance is 30% or less, and preferably the visible light transmittance is 10% or less. The visible light transmittance is specified as described above.

As a more specific configuration, in the example shown in FIG. 13A, the light-shielding layer 65 is a light-absorbing layer 66 that has visible light absorption properties. "Having visible light absorption properties" means that both the visible light transmittance and the visible light reflectance are 30% or less, and preferably both the visible light transmittance and the visible light reflectance are 10% or less. The visible light transmittance is specified as described above. The visible light reflectance is specified as the average value of the total light reflectance at each wavelength when measured at an incident angle of 45° every 1 nm in the measurement wavelength range of 380 nm to 780 nm using a spectrophotometer (Shimadzu Corporation's "UV-3100PC", compliant with JIS K 0115).

The light absorbing layer 66 may be a resin layer containing a dark pigment such as carbon black. In the example shown in FIG. 13A, the light absorbing layer 66 may be produced by patterning a coating film formed on the light-emitting side surface 42 using a photolithography technique. The light absorbing layer 66 may be produced by pattern printing a resin composition.

The light absorbing layer 66 may be a dielectric multilayer film or a metal compound film. The dielectric multilayer film or the metal compound film may be fabricated on the light-emitting side surface 42 by a dry process such as pattern deposition. An example of a metal compound film is a metal deposition film containing tungsten oxide.

That is, in the example shown in FIG. 13A, the translucent screen 20 includes a light absorbing layer 66 located on the light output side of the light control layer 40. The light absorbing layer 66 faces only a part of the light output side 62 of the second portion 60 from the light output side in the third direction D3. The part of the light output side 62 facing the light absorbing layer 66 includes a first end 62a which is the first side of the light output side 62 in the first direction D1, and is away from a second end 62b which is the second side of the light output side 62 in the first direction D1. According to the light absorbing layer 66 facing only a part of the light output side 62, the image light L13A1 that does not enter the first portion 50 can be absorbed by the light absorbing layer 66. According to this example, it is possible to suppress the image from being observed brightly from an unintended direction. In addition, the light absorbing layer 66 can absorb a part of the light L13A2 that enters the translucent screen 20 from the light output side. Therefore, the contrast of the image displayed on the translucent screen 20 can be improved.

In the example shown in FIG. 13B, the light-shielding layer 65 is a light-reflecting layer 67 having visible light reflectivity. "Having visible light reflectivity" means that the visible light reflectivity is 50% or more, and preferably the visible light reflectivity is 80% or more. The visible light reflectivity is specified as described above. The reflection in the light-reflecting layer 67 may be specular reflection, diffuse reflection, or directional diffuse reflection. The light-reflecting layer 67 may be a metal layer. The light-reflecting layer 67 as a metal layer may be produced by pattern deposition using a mask or the like. The light-reflecting layer 67 may be a dielectric multilayer film. The dielectric multilayer film may be produced on the light-emitting side surface 42 by a dry process such as pattern deposition. The light-reflecting layer 67 may be a resin layer containing a scattering material such as titanium oxide. The light-absorbing layer 66 as a resin layer may be produced by pattern printing a resin composition.

That is, in the example shown in FIG. 13B, the transmissive screen 20 includes a light reflecting layer 67 located on the light output side of the light control layer 40. The light reflecting layer 67 faces only a part of the light output side 62 of the second portion 60 from the light output side in the third direction D3. The part of the light output side 62 facing the light reflecting layer 67 includes a first end 62a which is the first side of the light output side 62 in the first direction D1, and is away from a second end 62b which is the second side of the light output side 62 in the first direction D1. According to the light reflecting layer 67 facing only a part of the light output side 62, the image light L13B1 that does not enter the first portion 50 can be reflected by the light reflecting layer 67. According to this example, it is possible to suppress the image from being observed brightly from an unintended direction. In addition, the image light L13B1 can be guided to the first portion 50 including the light diffusion portion 55 by reflection at the light reflecting layer 67. This improves the efficiency of use of the image light from the image light source 15, allowing the image to be displayed brighter. As a result, the contrast of the image displayed on the translucent screen 20 can be further improved.

As another modified example, as shown in Figures 14A and 14B, the light-shielding layer 65 located on the light-emitting side of the light control layer 40 may face the entire light-emitting side surface 62 of the second portion 60 from the light-emitting side in the third direction D3. As described above, the light-shielding layer 65 has visible light-shielding properties. According to this specific example, the backlight L14A2, L14B2 that enters the transmissive screen 20 from the light-entering side, other than the image light L14A1, L14B1, can be blocked by the light-shielding layer 65. Therefore, the image can be displayed brightly and clearly, and the contrast of the image can be significantly improved.

As a more specific configuration, the light-shielding layer 65 may be a light-absorbing layer 66 having visible light absorption properties. As described above, the light-absorbing layer 66 has visible light absorption properties. In the example shown in FIG. 14A, the light-absorbing layer 66 located on the light-emitting side of the light control layer 40 faces the entire area of the light-emitting side surface 62 of the second portion 60 from the light-emitting side in the third direction D3. According to this specific example, the light L14A2 incident on the transmissive screen 20 from the light-incoming side other than the image light L14A1 can be absorbed by the light-absorbing layer 66. In addition, the light L14A3 incident on the light-absorbing layer 66 from the light-emitting side is absorbed. Therefore, the image can be displayed brightly and clearly, and the contrast of the image displayed on the transmissive screen 20 can be significantly improved.

The light-shielding layer 65 may be a light-reflecting layer 67 having visible light absorption properties. As described above, the light-reflecting layer 67 has visible light reflectivity. In the example shown in FIG. 14B, the light-reflecting layer 67 located on the light-emitting side of the light control layer 40 faces the entire area of the light-emitting side surface 62 of the second portion 60 from the light-emitting side in the third direction D3. According to this specific example, the light-reflecting layer 67 can block light L14B2 that enters the transmissive screen from the light-incoming side other than the image light L14B1. Therefore, the image can be displayed brightly and clearly, and the contrast of the image can be significantly improved. In addition, light L14B3 that enters the light-reflecting layer 67 from the light-emitting side is reflected. When no image is displayed, the transmissive screen 20 functions as a mirror.

In the example shown in Figures 13A to 14B, the light blocking layer 65, the light absorbing layer 66, and the light reflecting layer 67 are adjacent to the light control layer 40. The light blocking layer 65, the light absorbing layer 66, and the light reflecting layer 67 may be located away from the light control layer 40 on the light output side of the light control layer 40 in the third direction D3.

As another example, the translucent screen 20 may have a decorative layer 68 that displays a design. As shown in FIG. 15, the decorative layer 68 is located on the light output side in the third direction D3 of the light control layer 40. The decorative layer 68 faces the light output side surface 62 of the second portion 60 from the light output side. The decorative layer 68 allows the viewer to observe the decorative layer 68 when no image is displayed. This improves the design of the translucent screen 20. In addition, the decorative layer 68 expresses a design, allowing the translucent screen 20 to be arranged in harmony with the surrounding environment. In addition, the decorative layer 68 can block some of the light L152 that enters the translucent screen 20 from the light input side, other than the image light L151. This allows the image to be displayed brightly and clearly, improving the contrast of the image.

The decorative layer 68 has a design formed thereon. The decorative layer 68 may have a design such as a figure, pattern, design, color, picture, photograph, character, mark, pictogram, letter, or number. The decorative layer 68 may also have a design expression that displays a background. For example, the decorative layer 68 may display a wood grain or marble pattern, a metallic texture, or a geometric pattern as a design that can harmonize the transparent screen 20 with the surrounding environment in which the transparent screen 20 is installed. The decorative layer 68 may be a resin layer containing a pigment. The decorative layer 68 may be formed by printing. The decorative layer 68 may be produced by pattern vapor deposition.

In the example shown in FIG. 15, the transmissive screen 20 includes a light-shielding layer 65 between the light control layer 40 and the decorative layer 68. The light-shielding layer 65 blocks light L152 that enters the transmissive screen 20 from the light-entering side, other than the image light L151. This allows the image to be displayed brightly and clearly, and the contrast of the image to be improved. In addition, the light-shielding layer 65 covers the decorative layer 68 from the back, so that the design formed by the decorative layer 68 can be displayed darkly and clearly. The light-shielding layer 65 may be a light-absorbing layer 66 or a light-reflecting layer 67. In the example shown in FIG. 15, the light-shielding layer 65 can be omitted.

In the example shown in FIG. 15, the decorative layer 68 is adjacent to the light control layer 40. The decorative layer 68 may be located away from the light control layer 40 on the light output side of the light control layer 40 in the third direction D3.

As another variation, as shown in FIG. 16, the translucent screen 20 or the light control layer 40 may include a colored layer 37. The colored layer 37 allows the image displayed on the translucent screen 20 to be toned.

Next, a first and second modified embodiment of the basic aspect of the embodiment described above will be described. The first and second modified embodiments are additional configurations to the basic aspect and its modified embodiments described above. In the following description and the drawings used in the following description, the same reference numerals as those used in the basic aspect and its modified embodiments described above will be used for parts that can be configured in the same way as the basic aspect and its modified embodiments described above, and duplicated descriptions will be omitted.

In the first modified embodiment, as shown in Figs. 17A to 19, the first portion 50 includes a light-shielding portion 56 constituting the first surface 51. The light-shielding portion 56 has visible light-shielding properties, similar to the light-shielding layer 65 described above. That is, the translucent screen 20 according to the first modified embodiment includes the first portion 50 and the second portion 60 arranged alternately in the first direction D1. The first portion 50 includes a first surface 51 and a second surface 52 that form an interface with the second portion 60. The first surface 51 and the second surface 52 face the first direction D1. The first portion 50 includes a light diffusion portion 55 having a light diffusion function and a light-shielding portion 56 constituting the first surface 51. The light-shielding portion 56 has visible light-shielding properties. The magnitude of the first angle θ1 between the first surface 51 and the first direction D1 is less than the magnitude of the second angle θ2 between the second surface 52 and the first direction D1.

According to the first modified embodiment in which the light shielding portion 56 is provided, the backlight other than the image light that enters the transmissive screen 20 from the light entrance side in the third direction D3 and travels toward the first portion 50 is shielded by the light shielding portion 56 and is prevented from entering the light diffusion portion 55. Therefore, the diffusion of the backlight other than the image light that passes through the transmissive screen 20 in the light diffusion portion 55 can be significantly suppressed. This can significantly improve the contrast of the image displayed on the transmissive screen 20. In addition, since the diffusion of the backlight is suppressed, the see-through property of the transmissive screen 20 as a transparent screen can be significantly improved. In addition, since the backlight can be suppressed from entering the first portion 50, the light diffusion function of the light diffusion portion 55 may be enhanced. This allows a high-contrast image to be displayed brightly and clearly.

As shown in Figures 17A and 18A, the light shielding portion 56 is a layer that spreads along the first surface 51. The thickness of the light shielding portion 56 may be constant or may not be constant. In the example shown in Figures 17A to 18C, the light shielding portion 56 is adjacent to the light diffusion portion 55. The first portion 50 is composed of only the light shielding portion 56 and the light diffusion portion 55. As shown in Figures 17B and 18B, when the first portion 50 includes the light entrance side surface 53, the light entrance side surface 53 may also be composed of the light shielding portion 56. Also, when the light shielding layer 65 described with reference to Figures 13A to 15 is provided on the light exit side surface 62, the light shielding portion 56 may be connected to the light shielding layer 65 as shown in Figures 17C and 18C. The light shielding portion 56 may be formed of the same material as the light shielding layer 65. The light shielding portion 56 may be formed seamlessly with the light shielding layer 65. The light-shielding portion 56 may be formed integrally with the light-shielding layer 65.

In the example shown in Figures 17A to 17C, the light shielding portion 56 is a light absorbing portion 57. The light absorbing portion 57 has visible light absorbing properties, similar to the light absorbing layer 66 described above. That is, the translucent screen 20 includes a first portion 50 and a second portion 60 arranged alternately in the first direction D1. The first portion 50 includes a first surface 51 and a second surface 52 that form an interface with the second portion 60. The first surface 51 and the second surface 52 face the first direction D1. The first portion 50 includes a light diffusion portion 55 having a light diffusing function and a light absorbing portion 57 that constitutes the first surface 51. The light absorbing portion 57 has visible light absorbing properties. The magnitude of the first angle θ1 between the first surface 51 and the first direction D1 is less than the magnitude of the second angle θ2 between the second surface 52 and the first direction D1.

In the translucent screen 20 having the light absorbing portion 57, the image light L17A1, L17C1 passes through the second surface 52 and enters the first portion 50, as described in the basic embodiment. The image light L17A1, L17C1 is efficiently diffused by the light diffusing portion 55 of the first portion 50 and exits from the light control layer 40 and the translucent screen 20.

Some of the image light L17A3, L17C3 is directed toward the first surface 51 without being diffused by the light diffusion section 55. Such image light L17A3, L17C3 is absorbed by the light absorption section 57. This makes it possible to prevent the image from being observed from an unintended specific direction, or the translucent screen 20 from being observed brightly from an unintended specific direction.

In addition, the backlight L17A2, L17B2, and L17C2 that enter the transmissive screen 20 from the light-incoming side and head toward the first portion 50, other than the image light L17A1 and L17C1, are absorbed by the light-absorbing portion 57. Most of the backlight L17A4 that passes through the transmissive screen 20 passes through the second portion 60. In other words, the diffusion of the backlight other than the image light L17A1 and L17C1 that passes through the transmissive screen 20 at the light-diffusing portion 55 can be significantly suppressed. In addition, a portion of the external light that enters the transmissive screen 20 from the light-outgoing side is also absorbed by the light-absorbing portion 57. As a result, the contrast of the image displayed on the transmissive screen 20 can be significantly improved. The see-through property of the transmissive screen 20 as a transparent screen can be significantly improved.

In addition, in the example shown in Figures 17A to 17C, the light diffusion function of the light diffusion section 55 can be enhanced because the backlight can be prevented from entering the first portion 50. This allows high-contrast images to be displayed brightly and clearly.

In the example shown in FIG. 17C, a light absorbing layer 66 is provided. In this example, not only the backlight L17C2 and L17C5 but also the external light L17C6 that enters the translucent screen 20 from the light exit side is absorbed by the light absorbing layer 66. This significantly improves the contrast of the image displayed on the translucent screen 20.

The light-shielding portion 56 may be configured in the same manner as the light-absorbing layer 66 described above. The light-shielding portion 56 may be a resin layer containing a dark-colored pigment such as carbon black. The light-shielding portion 56 may be a dielectric multilayer film or a metal compound film. The dielectric multilayer film or the metal compound film may be produced by a dry process such as pattern deposition. An example of a metal compound film is a metal deposition film containing tungsten oxide.

In the example shown in Figures 18A to 18C, the light shielding portion 56 is a light reflecting portion 58. The light reflecting portion 58 has visible light reflectivity, similar to the light reflecting layer 67 described above. That is, the translucent screen 20 includes a first portion 50 and a second portion 60 arranged alternately in the first direction D1. The first portion 50 includes a first surface 51 and a second surface 52 that form an interface with the second portion 60. The first surface 51 and the second surface 52 face the first direction D1. The first portion 50 includes a light diffusion portion 55 having a light diffusion function and a light reflecting portion 58 that constitutes the first surface 51. The light reflecting portion 58 has visible light reflectivity. The magnitude of the first angle θ1 between the first surface 51 and the first direction D1 is less than the magnitude of the second angle θ2 between the second surface 52 and the first direction D1.

In a translucent screen 20 having a light reflecting portion 58, the image light L18A1, L18C1 passes through the second surface 52 and enters the first portion 50, as described in the basic embodiment. The image light L18A1, L18C1 is efficiently diffused by the light diffusing portion 55 of the first portion 50 and exits from the light control layer 40 and the translucent screen 20.

Some of the image light L18A3, L18C3 heads toward the first surface 51 without being diffused by the light diffusion section 55. Such image light L18A3, L18C3 is reflected by the light reflection section 58. By reflection at the light reflection section 58, the image light L18A3, L18C3 can be directed toward the light output side. This improves the efficiency of use of the image light from the image light source 15, and allows the image to be displayed brightly. As a result, the contrast of the image displayed on the translucent screen 20 can be further improved. In addition, it is possible to prevent the image from being observed from an unintended specific direction, and to prevent the translucent screen 20 from being observed brightly from an unintended specific direction.

In addition, the backlight L18A2, L18C2 that enters the translucent screen 20 from the light entrance side and heads toward the first portion 50, other than the image light L18A1, L18C1, is reflected by the light reflecting portion 58 and is prevented from entering the light diffusing portion 55. The backlight L18A2, L18C2 reflected by the light reflecting portion 58 can be directed in a direction that is significantly inclined with respect to the third direction D3. Therefore, the diffusion of the backlight other than the image light L18A1, L18C1 that passes through the translucent screen 20 in the light diffusing portion can be significantly suppressed. This can significantly improve the contrast of the image displayed on the translucent screen 20. The see-through property of the translucent screen 20 as a transparent screen can be significantly improved.

In the example shown in FIG. 18C, a light reflecting layer 67 is provided. In this example, not only the backlight L18C2 and L18C5 but also the external light L18C6 that enters the translucent screen 20 from the light exit side is reflected by the light reflecting layer 67. This significantly improves the contrast of the image displayed on the translucent screen 20. Furthermore, when no image is displayed, the translucent screen 20 functions as a mirror.

The reflection at the light reflecting portion 58 may be specular reflection, diffuse reflection, or directional diffuse reflection, similar to the reflection at the light reflecting layer 67. The light reflecting portion 58 may be a resin layer containing a scattering material such as titanium oxide, similar to the light reflecting layer 67 described above.

The light reflecting portion 58 may be a metal layer or a dielectric multilayer film, similar to the light reflecting layer 67 described above. The light reflecting portion 58 may be a resin layer containing a scattering material such as titanium oxide. These light reflecting portions 58 can reflect the image light L18A3, L18C3 with high reflectance and direct it toward the light output side. Therefore, the efficiency of use of the image light from the image light source 15 can be further improved.

In the translucent screen 20 shown in FIG. 19, the light-shielding portion 56 includes a light-absorbing portion 57 and a light-reflecting portion 58. The light-absorbing portion 57 constitutes the first surface 51. The light-reflecting portion 58 is located between the light-absorbing portion 57 and the light-diffusing portion 55. The light-reflecting portion 58 is adjacent to the light-absorbing portion 57. The light-reflecting portion 58 is adjacent to the light-diffusing portion 55.

In the translucent screen 20 shown in FIG. 19, the image light L191 passes through the second surface 52 and enters the first portion 50, as described in the basic embodiment. The image light L191 is efficiently diffused by the light diffusion portion 55 of the first portion 50, and exits from the light control layer 40 and the translucent screen 20.

A portion of the image light L193 is directed toward the light reflecting portion 58 without being diffused by the light diffusing portion 55. This image light L193 is reflected by the light reflecting portion 58. By being reflected by the light reflecting portion 58, the image light L193 can be directed toward the light output side. This improves the efficiency of use of the image light from the image light source 15, and allows the image to be displayed brightly. As a result, the contrast of the image displayed on the translucent screen 20 can be further improved. In addition, it is possible to prevent the image from being observed from an unintended specific direction, and to prevent the translucent screen 20 from being observed brightly from an unintended specific direction.

In addition, the backlight L192, other than the image light L191, that enters the transmissive screen 20 from the light-incoming side and travels toward the first portion 50, is absorbed by the light-absorbing portion 57. Most of the backlight L194 that passes through the transmissive screen 20 passes through the second portion 60. In other words, the diffusion of the backlight other than the image light L191 that passes through the transmissive screen 20 at the light-diffusing portion 55 can be significantly suppressed. In addition, a portion of the external light that enters the transmissive screen 20 from the light-outgoing side is also absorbed by the light-absorbing portion 57. As a result, the contrast of the image displayed on the transmissive screen 20 can be significantly improved. The see-through properties of the transmissive screen 20 as a transparent screen can be significantly improved.

In addition, in the example shown in FIG. 19, the light diffusion function of the light diffusion section 55 may be enhanced because the backlight L192 can be prevented from entering the first portion 50. This allows high-contrast images to be displayed brightly and clearly.

In the first modified embodiment described above, the first surface 51 of the first portion 50 is constituted by the light shielding portion 56. In this example, the refractive index of the portion constituting the second surface 52 of the first portion 50 may be greater than the refractive index of the second portion 60. When the light diffusion portion 55 including the base material portion 55A and the light diffusion element 55B constitutes the second surface 52, the refractive index of the base material portion 55A may be greater than the refractive index of the second portion 60. With such a refractive index setting, as shown in FIG. 18A, FIG. 18C, and FIG. 19, the angle between the traveling direction of the image light and the first direction D1 can be reduced by refraction at the second surface 52. Therefore, the image light can be guided to the light reflecting portion 58 by refraction at the second surface 52. This can further improve the utilization efficiency of the image light from the image light source 15.

As described in the basic embodiment above, it is useful in the first modified embodiment to set the magnitude of the first angle θ to be greater than Arccos(1/n), where n is the refractive index of the second portion 60. With this angle setting, the magnitude of the first angle θ1 is not too small relative to the traveling direction angle θx between the traveling direction of the image light and the first direction. Therefore, the image light can be guided to the light reflecting portion 58. This can further improve the utilization efficiency of the image light from the image light source 15. In addition, it can be prevented that the image light is incident on the first surface 51 of the first portion 50 from the light entrance side in the third direction D3. Therefore, for example, it is possible to suppress the image light from being unintentionally absorbed by the light absorbing portion 57.

In the examples shown in Figures 17A to 19, the entire first surface 51 is constituted by the light-shielding portion 56. Only a portion of the first surface 51 may be constituted by the light-shielding portion 56. Also, although not shown, only the light-entering side surface 53 may be constituted by the light-shielding portion 56.

Next, the second modified embodiment will be described. In the second modified embodiment, as shown in FIG. 20, the first portion 50 includes a low refractive index portion 59 that constitutes the first surface 51.

As an example of the second modified embodiment, the refractive index of the low refractive index portion 59 may be lower than the refractive index of the portion adjacent to the low refractive index portion 59 of the first portion 50. That is, this translucent screen 20 includes a first portion 50 and a second portion 60 arranged alternately in the first direction D1. The first portion 50 includes a first surface 51 and a second surface 52 that form an interface with the second portion 60. The first surface 51 and the second surface 52 face the first direction D1. The first portion 50 includes a light diffusion portion 55 having a light diffusion function and a low refractive index portion 59 that constitutes the first surface 51. The magnitude of the first angle θ1 between the first surface 51 and the first direction D1 is less than the magnitude of the second angle θ2 between the second surface 52 and the first direction D1. The refractive index of the low refractive index portion 59 may be lower than the refractive index of the portion adjacent to the low refractive index portion 59 of the first portion 50. In this example, when the light diffusion section 55 including the base material section 55A and the light diffusion element 55B is adjacent to the low refractive index section 59, the refractive index of the base material section 55A may be greater than the refractive index of the low refractive index section 59.

According to this example, the interface of the low refractive index section 59 on the light diffusion section 55 side is an interface with a refractive index difference, and functions as a reflective surface. Therefore, the image light L20A2 that is not diffused by the light diffusion section 55 of the first part 50 can be reflected by the low refractive index section 59, for example, totally reflected, and directed toward the light output side. This improves the efficiency of use of the image light from the image light source 15, and allows the image to be displayed brightly. As a result, the contrast of the image displayed on the translucent screen 20 can be improved.

In another example of the second modified embodiment, the refractive index of the low refractive index portion 59 may be lower than that of the second portion 60. That is, the translucent screen 20 includes first portions 50 and second portions 60 arranged alternately in the first direction D1. The first portion 50 includes a first surface 51 and a second surface 52 that form an interface with the second portion 60. The first surface 51 and the second surface 52 face the first direction D1. The first portion 50 includes a light diffusion portion 55 having a light diffusion function and a low refractive index portion 59 that constitutes the first surface 51. The magnitude of the first angle θ1 between the first surface 51 and the first direction D1 is less than the magnitude of the second angle θ2 between the second surface 52 and the first direction D1. The refractive index of the low refractive index portion 59 may be lower than that of the second portion 60.

According to this example, some of the backlight L203 that enters the translucent screen 20 from the light-entering side and travels toward the first portion 50, other than the image light L201, is reflected, for example, totally reflected, by the first surface 51, and is prevented from entering the light diffusion section 55. This backlight L203 can be directed in a direction that is greatly inclined with respect to the third direction D3 by reflection on the first surface 51. Therefore, it is possible to prevent the backlight L203, other than the image light L201 and L202 that transmits through the translucent screen 20, from being diffused by the light diffusion section 55. This can improve the contrast of the image displayed on the translucent screen 20. In addition, it is possible to improve the see-through property of the translucent screen 20 as a transparent screen.

In the translucent screen 20 shown in FIG. 20, the refractive index of the low refractive index portion 59 is lower than the refractive index of the portion adjacent to the low refractive index portion 59 of the first portion 50, and is lower than the refractive index of the second portion 60. The refractive index of the low refractive index portion 59 may be lower than the refractive index of the portion adjacent to the low refractive index portion 59 of the first portion 50, and is equal to or higher than the refractive index of the second portion 60. The refractive index of the low refractive index portion 59 may be equal to or higher than the refractive index of the portion adjacent to the low refractive index portion 59 of the first portion 50, and is lower than the refractive index of the second portion 60.

D1: first direction, D2: second direction, D3: third direction, 7: background, 9: observer, 10: display system, 15: image light source, 15C: light source center, 20: transmissive screen, 21: light entrance side, 22: light exit side, 31: substrate, 31A: first substrate, 31B: second substrate, 33: bonding layer, 33A: first bonding layer, 33B: second bonding layer, 35: functional layer, 36: surface layer, 36A: first surface layer, 36B: second surface layer, 37: colored layer, 38: substrate, 39: winding core, 40: light control layer, 41 : Light-entering side, 42: Light-emitting side, 45: Light control layer body, 45a: Groove, 48: Base portion, 50: First portion, 51: First surface, 52: Second surface, 53: Light-entering side, 54: Light-emitting side, 55: Light-diffusing portion, 55A: Base material portion, 55B: Light-diffusing element, 56: Light-shielding portion, 57: Light-absorbing portion, 58: Light-reflecting portion, 59: Low refractive index portion, 60: Second portion, 61: Light-entering side, 62: Light-emitting side, 62a: First end portion, 62b: Second end portion, 65: Light-shielding layer, 66: Light-absorbing layer, 67: Light-reflecting layer, 68: Decorative layer

Claims (28)

A translucent screen onto which image light is projected from an image light source,
The first and second portions are arranged alternately in a first direction,
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
a distance between the first surface and the second surface along the first direction is larger on the light exit side than on the light entrance side;
the second surface of the first portion is located on a second side closer to the image light source in the first direction, and the first surface of the first portion is located on a first side away from the image light source in the first direction;
The first portion includes a light diffusion portion having a light diffusion function,
A transmission screen, wherein a magnitude of a first angle between the first surface and the first direction is equal to or greater than 40° and is less than a magnitude of a second angle between the second surface and the first direction. The translucent screen according to claim 1, wherein the first portion includes a light-shielding portion that constitutes the first surface, and the light-shielding portion has visible light-shielding properties. The translucent screen according to claim 1 or 2, wherein the first portion includes a light absorbing portion that constitutes the first surface, and the light absorbing portion has visible light absorption properties. The translucent screen according to claim 3, wherein the first portion includes a light reflecting portion located between the light absorbing portion and the light diffusing portion, and the light reflecting portion has visible light reflectivity. The translucent screen according to claim 1 or 2, wherein the first portion includes a light reflecting portion that constitutes the first surface, and the light reflecting portion has visible light reflectivity. The translucent screen according to claim 4 or 5, wherein the light reflecting portion includes a metal layer. The translucent screen according to any one of claims 4 to 6, wherein the refractive index of the portion constituting the second surface of the first portion is higher than the refractive index of the second portion. the first portion includes a low refractive index portion that constitutes the first surface,
2. The translucent screen according to claim 1, wherein the refractive index of the low refractive index portion is lower than the refractive index of a portion of the first portion adjacent to the low refractive index portion. the first portion includes a low refractive index portion that constitutes the first surface,
9. The translucent screen according to claim 1, wherein the refractive index of the low refractive index portion is lower than the refractive index of the second portion. The translucent screen according to claim 1, wherein the refractive index of the portion constituting the first surface of the first portion is higher than the refractive index of the second portion. The translucent screen according to any one of claims 1 to 10, wherein the magnitude of the first angle is greater than Arccos(1/n) and is less than or equal to 80°, where n is the refractive index of the second portion. The translucent screen according to any one of claims 1 to 11, wherein the magnitude of the first angle of one first portion is greater than the magnitude of the first angle of another first portion located on the first side in the first direction relative to the one first portion. The translucent screen according to claim 12, wherein the magnitude of the first angle of any one of the first portions is equal to or greater than the magnitude of the first angle of any other one of the first portions that is located on the first side in the first direction from the one of the first portions. The translucent screen according to any one of claims 1 to 13, wherein the magnitude of the second angle is greater than or equal to 85° and less than or equal to 90°. a light control layer including the first portion and the second portion;
a light-shielding layer located on the light output side of the light control layer,
The light-shielding layer has a visible light-shielding property,
The translucent screen according to any one of claims 1 to 14, wherein the light-shielding layer faces a light-outgoing side surface of the second portion from the light-outgoing side. a light control layer including the first portion and the second portion;
a light absorbing layer located on the light output side of the light control layer,
The light absorbing layer has a visible light absorbing property,
16. The translucent screen according to claim 1, wherein the light absorbing layer faces the light exiting side surface of the second portion from the light exiting side. a light control layer including the first portion and the second portion;
a light reflecting layer located on the light output side of the light control layer,
The light reflective layer has visible light reflectivity,
16. The translucent screen according to claim 1, wherein the light reflecting layer faces a light exiting side surface of the second portion from the light exiting side. a light control layer including the first portion and the second portion;
a decorative layer that is located on the light output side of the light control layer and displays a design;
The translucent screen according to any one of claims 1 to 14, wherein the decorative layer faces a light exiting side surface of the second portion from the light exiting side. a light control layer including the first portion and the second portion;
a light-shielding layer located on the light output side of the light control layer,
The light-shielding layer has a visible light-shielding property,
the light-shielding layer faces only a part of the light-emitting side surface of the second portion from the light-emitting side,
The translucent screen according to any one of claims 1 to 14, wherein the portion includes an end portion on the first side in the first direction of the light exit side surface and is spaced apart from an end portion on the second side in the first direction of the light exit side surface. a light control layer including the first portion and the second portion;
a light absorbing layer located on the light output side of the light control layer,
The light absorbing layer has a visible light absorbing property,
the light absorbing layer faces only a part of the light output side surface of the second portion from the light output side,
The translucent screen according to any one of claims 1 to 14, wherein the portion includes an end portion on the first side in the first direction of the light exit side surface and is spaced apart from an end portion on the second side in the first direction of the light exit side surface. a light control layer including the first portion and the second portion;
a light reflecting layer located on the light output side of the light control layer,
The light reflective layer has visible light reflectivity,
the light reflecting layer faces only a part of the light exiting side surface of the second portion from the light exiting side,
The translucent screen according to any one of claims 1 to 14, wherein the portion includes an end portion on the first side in the first direction of the light exit side surface and is spaced apart from an end portion on the second side in the first direction of the light exit side surface. a light control layer body having a plurality of grooves;
a plurality of first portions located within the groove;
The light control layer body includes a sheet-like base portion, a plurality of second portions arranged on the base portion,
The second portion constitutes a portion between adjacent grooves,
the first portions and the second portions are alternately arranged in a first direction ;
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
the first portion includes a light diffusion portion located between the first surface and the second surface and having a light diffusion function, and a light blocking portion constituting the first surface,
The light-shielding portion has a visible light-shielding property,
A transmissive screen, wherein a magnitude of a first angle between the first surface and the first direction is less than a magnitude of a second angle between the second surface and the first direction. a light control layer body having a plurality of grooves;
a plurality of first portions located within the groove;
The light control layer body includes a sheet-like base portion, a plurality of second portions arranged on the base portion,
The second portion constitutes a portion between adjacent grooves,
the first portions and the second portions are alternately arranged in a first direction ;
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
the first portion includes a light diffusing portion located between the first surface and the second surface and having a light diffusing function, and a light absorbing portion constituting the first surface,
The light absorbing portion has visible light absorbing properties,
A transmissive screen, wherein a magnitude of a first angle between the first surface and the first direction is less than a magnitude of a second angle between the second surface and the first direction. a light control layer body having a plurality of grooves;
a plurality of first portions located within the groove;
The light control layer body includes a sheet-like base portion, a plurality of second portions arranged on the base portion,
The second portion constitutes a portion between adjacent grooves,
the first portions and the second portions are alternately arranged in a first direction ;
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
The first portion includes a light diffusing portion located between the first surface and the second surface and having a light diffusing function, and a light reflecting portion constituting the first surface,
The light reflecting portion has visible light reflectivity,
A transmissive screen, wherein a magnitude of a first angle between the first surface and the first direction is less than a magnitude of a second angle between the second surface and the first direction. The first and second portions are arranged alternately in a first direction,
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
The first portion includes a light diffusion portion having a light diffusion function and a low refractive index portion constituting the first surface,
a first angle between the first plane and the first direction is less than a second angle between the second plane and the first direction;
A transmission screen, wherein the refractive index of the low refractive index portion is lower than the refractive index of a portion of the first portion adjacent to the low refractive index portion. The first and second portions are arranged alternately in a first direction,
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
The first portion includes a light diffusion portion having a light diffusion function and a low refractive index portion constituting the first surface,
a first angle between the first plane and the first direction is less than a second angle between the second plane and the first direction;
A transmission screen, wherein the refractive index of the low refractive index portion is lower than the refractive index of the second portion. The first and second portions are arranged alternately in a first direction,
the first portion includes a first surface and a second surface that interface with the second portion;
the first surface and the second surface face each other in the first direction,
The first portion includes a light diffusion portion having a light diffusion function,
a first angle between the first plane and the first direction is less than a second angle between the second plane and the first direction;
A transmissive screen, wherein the refractive index of the portion constituting the first surface of the first portion is higher than the refractive index of the second portion. A transmission screen according to any one of claims 1 to 27;
an image light source that projects image light onto the translucent screen.