Image Projection System

Abstract

The purpose of the present invention is to provide an image projection system which provides a projected image that can be viewed more easily.　The image projection system (10A) according to the present invention has: an image projection device (12) that emits projection light which is linearly polarized light; a screen (14A) onto which the projection light emitted by the image projection device (12) is projected; and a light absorption anisotropic layer (16A) which is disposed between the image projection device (12) and the screen (14A) and through which the projection light passes. The light absorption anisotropic layer (16A) contains a dichromatic substance. The transmittance center axis of the light absorption anisotropic layer (16A) is directed in the direction of the screen (14A).

Description

[Technical Field]

[0001] The present invention relates to an image projection system. [Background technology]

[0002] Image projection systems that project various images and text information onto a screen are widely used. For example, Patent Document 1 discloses the development of a so-called head-up display as one type of in-vehicle display that projects various information as an image onto a window glass or the like using an image projection device to convey the information to the driver. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 3-209210 Summary of the Invention [Problem to be solved by the invention]

[0004] In image projection systems, there is a demand for projected images to be more easily visible. The present inventors have studied the image projection system described in Patent Document 1 and found that the above characteristics are not necessarily sufficient and that further improvements are necessary.

[0005] In view of the above-described circumstances, an object of the present invention is to provide an image projection system that makes the projected image easier to see. [Means for solving the problem]

[0006] The present inventors have found that the above problems can be solved by the following configuration.

[0007] (1) an image projection device that emits projection light that is linearly polarized; a screen onto which projection light emitted from the image projection device is irradiated; an optically absorbing anisotropic layer disposed between the image projection device and the screen, through which projection light passes; the light absorbing anisotropic layer contains a dichroic material, An image projection system, wherein the central axis of transmittance of the light-absorbing anisotropic layer is oriented toward a screen. (2) The image projection system according to (1), wherein the area of ​​the screen that is irradiated with the projection light is located in the direction in which the central axis of transmittance of the light-absorbing anisotropic layer extends. (3) An image projection system according to (1) or (2), wherein the angle formed by the line connecting the center of the transmission window of the image projection device and the center of the irradiation area of ​​the projection light on the screen and the central axis of transmittance of the optically absorbing anisotropic layer is 0 to 30°. (4) The optically absorbing anisotropic layer contains a dichroic material, The image projection system according to any one of (1) to (3), wherein the content of the dichroic material is 10.0 mass % or more with respect to the total mass of the light absorption anisotropic layer. (5) The image projection system according to any one of (1) to (4), wherein the screen includes a reflective layer that reflects the projection light. (6) The image projection system according to (5), wherein the reflective layer is a cholesteric liquid crystal layer or a multilayer reflective film. (7) The image projection system according to any one of (1) to (6), further comprising a B plate disposed between the image projection device and the light-absorbing anisotropic layer, through which the projection light passes. (8) The image projection system according to any one of (1) to (7), which is used as an in-vehicle head-up display. (9) The image projection system according to (8), wherein the windshield of the vehicle is used as the screen. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an image projection system that makes the projected image easier to see. [Brief explanation of the drawings]

[0009] [Figure 1]1 is a schematic diagram illustrating a first embodiment of an image projection system. [Figure 2] FIG. 2 is a schematic diagram for explaining a screen. [Figure 3] FIG. 2 is a cross-sectional view of an example of an optically absorptive anisotropic layer. [Figure 4] FIG. 2 is a plan view of an example of an optically absorptive anisotropic layer. [Figure 5] FIG. 10 is a schematic diagram for explaining the orientation of the transmittance central axis. [Figure 6] FIG. 10 is a schematic diagram showing a modification of the first embodiment of the image projection system. [Figure 7] FIG. 2 is a schematic diagram illustrating a second embodiment of an image projection system. [Figure 8] FIG. 10 is a schematic diagram illustrating a third embodiment of an image projection system. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below. The following description of the components may be based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0011] In this specification, "(meth)acrylic" is used to mean "either one or both of acrylic and methacrylic", and "(meth)acryloyl" is used to mean "either one or both of acryloyl and methacryloyl". The bonding direction of a divalent group (e.g., -COO-) represented in this specification is not particularly limited. For example, when L in XLY is -COO-, if the position bonded to the X side is *1 and the position bonded to the Y side is *2, L may be *1-O-CO-*2 or *1-CO-O-*2.

[0012] In the present invention, visible light refers to electromagnetic waves having wavelengths visible to the human eye, in the wavelength range of 380 to 780 nm, while invisible light refers to light having wavelengths less than 380 nm or greater than 780 nm.

[0013] A feature of the image projection system of the present invention is that a light-absorbing anisotropic layer, through which projection light passes, is disposed between the image projection device and the screen. As will be described later, the central axis of transmittance in the optically absorptive anisotropic layer faces the screen, particularly the area of ​​the screen illuminated by the projection light. Therefore, of the projection light emitted from the image projection device, light that is not parallel to the central axis of transmittance is easily absorbed, and light that would brightly illuminate the area around the illuminated area where the projected image is projected is absorbed. As a result, the projected image is more easily visible.

[0014] <First embodiment> FIG. 1 shows a schematic diagram of a first embodiment of an image projection system according to the present invention. The image projection system 10A shown in FIG. 1 includes an image projection device 12, a screen 14A, and an optically absorbing anisotropic layer 16A. As indicated by the dashed line in FIG. 1, most of the projection light emitted from the transmission window 20 of the image projection device 12 passes through the optically absorbing anisotropic layer 16A, is irradiated onto a predetermined projection light-irradiated area on the screen 14A, and is reflected from the irradiation area. As a result, the observer OB can observe a virtual image of the image projected on the screen 14A. More specifically, in the image projection system 10A shown in FIG. 1, the projection light is emitted toward a partial irradiation area 22 on the screen 14A shown in FIG. 2, and the projection light is reflected from the irradiation area 22. As a result, the observer OB can observe a projected image in the irradiation area 22 of the screen 14A. In other words, the irradiation area 22 corresponds to the area on the screen 14 where the projection light is projected (reflected).

[0015] The black arrow in the optically absorptive anisotropic layer 16A indicates the central transmittance axis. As will be described later, the central transmittance axis refers to the direction in which the transmittance is highest when the transmittance is measured by changing the tilt angle (polar angle) and tilt direction (azimuthal angle) relative to the normal direction of the optically absorptive anisotropic layer 16A. Therefore, when light travels along this central transmittance axis, the light is less likely to be absorbed. On the other hand, the more the light passing through the optically absorptive anisotropic layer 16A deviates from the parallel relationship with the central transmittance axis, the more easily the light is absorbed. 1, the direction of projection light emitted from the transmission window 20 of the image projector 12 as indicated by the dashed line is parallel to the central axis of transmittance of the optically absorptive anisotropic layer 16A. Therefore, such projection light is unlikely to be absorbed by the optically absorptive anisotropic layer 16A. On the other hand, some of the projection light emitted from the transparent window 20 of the image projector 12 is not emitted in the desired direction, as indicated by the white arrow. This light brightly illuminates the area around the area where the observer views the projected image, resulting in a decrease in the contrast of the projected image and making it difficult for the observer to view the projected image. In the image projection system 10A, the central transmittance axis of the optically absorptive anisotropic layer 16A faces the screen. More specifically, the screen is disposed in the direction in which the central transmittance axis extends. This prevents light emitted in a direction different from the desired direction, as indicated by the white arrow, from passing through the screen 14A. As a result, the contrast of the projected image is increased, making it easier for the viewer to view the projected image.

[0016] In FIG. 1, an irradiation area 22 of the screen 14A that is irradiated with the projection light is located in the direction in which the central axis of transmittance of the optically absorptive anisotropic layer 16A extends. 1, a line connecting the center of the transmission window 20 of the image projector 12 and the center of the projection light irradiated area 22 on the screen 14A is parallel to the transmittance central axis of the optically absorptive anisotropic layer 16A. However, the present invention is not limited to the parallel form described above. The angle formed by the line connecting the center of the transmission window 20 of the image projector 12 and the center of the projection light irradiated area 22 on the screen 14A and the transmittance central axis of the optically absorptive anisotropic layer 16A is preferably 0 to 30°, more preferably 0 to 20°, and even more preferably 0 to 15°. The effects of the present invention are more excellent within the above ranges. The center of the transmission window 20 of the image projection device 12 means the position of the center of a circumscribing circle when the circumscribing circle inscribes the transmission window 20 . Moreover, the center of the irradiation area 22 of the projection light on the screen 14A means the position of the center of a circumscribing circle when the circumscribing circle inscribes the irradiation area 22.

[0017] The angle θ formed between the central axis of transmittance of the optically absorptive anisotropic layer and the normal direction to the surface of the optically absorptive anisotropic layer is not particularly limited, but is preferably 0 to 60°.

[0018] 1, the image projection device 12 and the optically absorptive anisotropic layer 16A are arranged apart from each other, but this is not limiting and they may be in contact with each other. Furthermore, the image projection device 12 and the optically absorptive anisotropic layer 16A may be joined via a pressure-sensitive adhesive layer or an adhesive layer.

[0019] Hereinafter, each of the components (image projection device 12, screen 14, and light-absorption anisotropic layer 16A) that make up image projection system 10A will be described in detail.

[0020] (Image projection device) The image projection device 12 is not particularly limited in configuration as long as it can emit projection light that is linearly polarized, and any known image display device can be used.

[0021] The image projection device 12 may include a polarizer to emit projection light that is linearly polarized. The polarizer used in the present invention is not particularly limited as long as it is a member that has the function of converting light into specific linearly polarized light, and any conventionally known polarizer can be used. Examples of polarizers include iodine-based polarizers, dye-based polarizers using dichroic dyes, and polyene-based polarizers. Iodine-based polarizers and dye-based polarizers include coated polarizers and stretched polarizers, both of which are applicable. As coated polarizers, polarizers in which a dichroic organic dye is oriented by utilizing the orientation of a liquid crystal compound are preferred, and as stretched polarizers, polarizers produced by adsorbing iodine or a dichroic dye into polyvinyl alcohol and stretching the resulting mixture are preferred. In the image projection device 12, the position where the polarizer is disposed is not particularly limited, and may be, for example, on the transmission window 20 of the image projection device 12. When the image projection device 12 includes a liquid crystal display device, a polarizer disposed on the viewing side of the liquid crystal display device may be used as the polarizer.

[0022] In the image projection device 12, projection light is emitted from a transmission window 20. The transmission window 20 may be a simple opening or a transparent portion through which the projection light passes. The transparent portion may be made of a glass substrate, a transparent resin film, or the like. The shape of the transmission window 20 when viewed from above is not particularly limited, and may be circular or polygonal.

[0023] The method for changing the imaging distance of the virtual image in the image projection device 12 is not particularly limited, and known methods can be used. Examples of methods for changing the imaging distance of a virtual image in the image projection device 12 include moving the image generation surface (screen) (see JP 2017-021302 A), switching between multiple optical paths with different optical path lengths (see WO 2015 / 190157 A), changing the optical path length by inserting and / or moving a mirror, changing the focal length by using a lens assembly as an imaging lens, moving the image projection device 12, switching between multiple projectors with different virtual image imaging distances, and using a variable focus lens (see WO 2010 / 116912 A).

[0024] As an example of the image projection device 12, an LCOS (Liquid Crystal on Silicon) projector is used. Examples of such projectors include a projector, a laser projector, and a liquid crystal projector (liquid crystal display device).

[0025] (Screen 14A) The configuration of the screen 14A is not particularly limited, and examples thereof include a component (e.g., a half mirror) that reflects projection light carrying an image and can display the image carried in the projection light as a projected image using the reflected light of the projection light, and more specifically, a glass plate. The screen 14A may also be a laminated glass having an interlayer film disposed between two glass plates. The interlayer film is not particularly limited, and examples of materials for forming the interlayer film include polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer, chlorine-containing resin, and polyurethane.

[0026] In FIG. 1, the screen 14A is flat, but it may have a curved surface in part, or may be entirely curved.

[0027] As shown in FIG. 2, only a partial area of ​​the screen 14A may be set as an irradiation area 22 of the projection light emitted from the image projection device 12, or the entire screen may be set as an irradiation area.

[0028] As will be described later, when the image display system of the present invention is used as an in-vehicle head-up display, the windshield of the vehicle can be used as a screen.

[0029] (Light absorption anisotropic layer 16A) The optically absorptive anisotropic layer 16A has a central transmittance axis, and the light transmittance is higher in the direction of the central transmittance axis. The transmittance central axis is the direction with the highest transmittance when the transmittance is measured while changing the tilt angle (polar angle) and tilt direction (azimuthal angle) relative to the normal to the surface of the optically absorptive anisotropic layer. Specifically, the Mueller matrix at a wavelength of 550 nm is measured using an AxoScan OPMF-1 (manufactured by OptoScience). More specifically, during measurement, the azimuthal angle at which the transmittance central axis is tilted is first determined. Next, within a plane containing the normal to the optically absorptive anisotropic layer along that azimuthal angle (a plane containing the transmittance central axis and perpendicular to the layer surface), the Mueller matrix at a wavelength of 550 nm is measured while changing the polar angle, which is the angle with respect to the normal to the surface of the optically absorptive anisotropic layer, in 1° increments from -70 to 70°, thereby deriving the transmittance of the optically absorptive anisotropic layer. The resulting direction with the highest transmittance is determined as the transmittance central axis. The central axis of transmittance means the direction of the absorption axis (the long axis direction of the molecule) of the dichroic material contained in the light absorption anisotropic layer.

[0030] The structure of the optically absorptive anisotropic layer 16A is not particularly limited as long as it has the transmittance central axis described above, but it is preferable that the layer 16A contains a dichroic material D as shown in FIGS. Fig. 3 is a cross-sectional view of the optically absorptive anisotropic layer 16A, and Fig. 4 is a plan view of the optically absorptive anisotropic layer 16A shown in Fig. 3. Fig. 3 is a cross-sectional view taken along line A-A in Fig. 4. 3, direction X and direction Z indicate the orientations of two coordinate axes that are perpendicular to each other on the observation surface. Direction Z is parallel to the thickness direction of the optically absorptive anisotropic layer 16A. In FIG. 4, direction X and direction Y indicate the orientations of two coordinate axes that are perpendicular to each other on the observation surface. As will be described later, the dichroic material D is a material that exhibits a difference in absorption intensity when irradiated with two linearly polarized lights whose electric vectors are oriented 90° apart.

[0031] In the optically absorptive anisotropic layer 16A, the dichroic material D is aligned with its major axis direction tilted relative to the surface of the optically absorptive anisotropic layer 16A. 3 and 4, the direction of the long axis of the dichroic material D projected onto the surface of the optically absorptive anisotropic layer 16A is parallel to the X-axis direction (the horizontal direction of the paper). Therefore, the X-axis direction (the horizontal direction of the paper) corresponds to the direction in which the transmittance for linearly polarized light is lowest in the in-plane direction of the optically absorptive anisotropic layer 16A. In other words, the direction of the outlined dashed arrow (the horizontal direction of the paper) shown in FIG. 4 corresponds to the azimuth angle at which the central axis of transmittance is tilted. 3, the dichroic substance D in the optically absorptive anisotropic layer 16A is tilted by θ° with respect to the normal direction of the optically absorptive anisotropic layer 16A. Therefore, the central axis of transmittance of the optically absorptive anisotropic layer 16A is parallel to the X direction and is tilted by θ° with respect to the normal direction to the surface of the optically absorptive anisotropic layer 16A. It is preferable that the angle θ be adjusted so that the angle formed by the line connecting the center of the transmission window 20 of the image projection device 12 and the center of the projection light irradiation area 22 on the screen 14A and the transmittance central axis of the light-absorbing anisotropic layer 16A falls within a predetermined range.

[0032] The azimuth angle of the transmittance central axis of the optically absorptive anisotropic layer 16A (the azimuth angle at which the transmittance central axis is tilted) is not particularly limited, but it is preferable that the direction of the transmittance central axis orthogonally projected onto the surface of the optically absorptive anisotropic layer 16A (corresponding to the azimuth angle at which the transmittance central axis is tilted) is parallel to the direction of the linearly polarized light that is the projection light emitted from the image projection device 12. More specifically, the direction in which the central transmittance axis is orthogonally projected onto the surface of the optically absorptive anisotropic layer corresponds to the direction in which the central transmittance axis TA extends when observed from the normal direction to the surface of the optically absorptive anisotropic layer, and is represented by a black line in Fig. 5. The white arrow in Fig. 5 indicates the direction of linearly polarized light, and as shown in Fig. 5, it is preferable that the direction of linearly polarized light and the direction in which the black line extends are parallel.

[0033] The central axis of transmittance of the optically absorptive anisotropic layer 16A also corresponds to the direction in which the dichroic material D is aligned. In other words, the central axis of transmittance of the optically absorptive anisotropic layer 16A also corresponds to the direction in which the major axes of the dichroic material D are aligned. Therefore, the central axis of transmittance of the optically absorptive anisotropic layer 16A can also be said to be the absorption axis of the optically absorptive anisotropic layer 16A. Furthermore, when the image display device includes a polarizer, the angle formed by the direction of the axis of transmittance of the optically absorptive anisotropic layer 16A projected onto the surface of the optically absorptive anisotropic layer 16 and the absorption axis of the polarizer included in the image display device is preferably 80 to 90°.

[0034] The thickness of the optically absorptive anisotropic layer 16A is not particularly limited, but is often 0.1 to 10 μm.

[0035] Techniques for orienting the dichroic material D in the desired direction include techniques for fabricating polarizers using the dichroic material D and techniques for fabricating guest-host liquid crystal cells. For example, the techniques used in the methods for fabricating dichroic polarizing elements described in JP-A-11-305036 and JP-A-2002-090526 and the methods for fabricating guest-host liquid crystal displays described in JP-A-2002-099388 and JP-A-2016-027387 can also be used to fabricate the light absorption anisotropic layer 16A.

[0036] To prevent the light absorption characteristics of the optically absorptive anisotropic layer 16A from fluctuating depending on the environment in which it is used, it is preferable to fix the orientation of the dichroic material D by forming a chemical bond. For example, the orientation can be fixed by promoting polymerization of the host liquid crystal, the dichroic material D, or a polymerizable component that is added as needed.

[0037] Alternatively, the light absorption anisotropic layer 16A can be produced by infiltrating the dichroic substance D into a polymer film and aligning the dichroic substance along the orientation of the polymer molecules in the polymer film.

[0038] [Dichroic substance] In the present invention, as described above, the dichroic material means a compound whose absorbance varies depending on the direction. In the light absorption anisotropic layer, the dichroic material may be fixed by polymerization.

[0039] The dichroic material is not particularly limited, and examples thereof include visible light absorbing materials (dichroic dyes), luminescent materials (fluorescent materials, phosphorescent materials), ultraviolet absorbing materials, infrared absorbing materials, nonlinear optical materials, carbon nanotubes, and inorganic materials (e.g., quantum rods), and conventionally known dichroic materials (preferably dichroic dyes) can be used. Specifically, paragraphs

[0067] to

[0071] of Japanese Patent Application Laid-Open No. 2013-228706, paragraphs

[0008] to

[0026] of Japanese Patent Application Laid-Open No. 2013-227532, paragraphs

[0008] to

[0015] of Japanese Patent Application Laid-Open No. 2013-209367, paragraphs

[0045] to

[0058] of Japanese Patent Application Laid-Open No. 2013-109090, paragraphs

[0012] to

[0029] of Japanese Patent Application Laid-Open No. 2013-101328, 017] paragraph, paragraphs

[0051] to

[0065] of JP 2013-037353 A, paragraphs

[0049] to

[0073] of JP 2012-063387 A, paragraphs

[0016] to

[0018] of JP 11-305036 A, paragraphs

[0009] to

[0011] of JP 2001-133630 A, paragraphs

[0030] to

[0169] of JP 2011-215337 A, and paragraphs

[0021] to [00 75] paragraph, paragraphs

[0011] to

[0025] of JP 2010-215846 A, paragraphs

[0017] to

[0069] of JP 2011-048311 A, paragraphs

[0013] to

[0133] of JP 2011-213610 A, paragraphs

[0074] to

[0246] of JP 2011-237513 A, paragraphs

[0005] to

[0051] of JP 2016-006502 A, paragraphs

[0005] to [

[0041] , paragraphs

[0008] to

[0062] of WO2016 / 136561, paragraphs

[0014] to

[0033] of WO2017 / 154835, paragraphs

[0014] to

[0033] of WO2017 / 154695, paragraphs

[0013] to

[0037] of WO2017 / 195833, and paragraphs

[0014] to

[0034] of WO2018 / 164252.

[0040] As the dichroic substance, a dichroic azo dye compound is preferred. The dichroic azo dye compound refers to an azo dye compound whose absorbance varies depending on the direction. The dichroic azo dye compound may or may not exhibit liquid crystallinity. When the dichroic azo dye compound exhibits liquid crystallinity, it may exhibit either nematic or smectic properties. The temperature range in which the liquid crystal phase is exhibited is preferably room temperature (approximately 20 to 28°C) to 300°C, and more preferably 50 to 200°C from the viewpoints of ease of handling and suitability for production.

[0041] In the present invention, two or more dichroic substances may be used in combination. For example, in order to make the resulting light absorption anisotropic layer closer to black, it is preferable to use in combination at least one dichroic substance having a maximum absorption wavelength in the wavelength range of 370 nm or more and less than 500 nm and at least one dichroic substance having a maximum absorption wavelength in the wavelength range of 500 nm or more and less than 700 nm.

[0042] As described below, the optically absorptive anisotropic layer can be formed using a composition for forming an optically absorptive anisotropic layer. In the composition for forming an optically absorptive anisotropic layer, the dichroic substance may have a crosslinkable group. When the dichroic substance has a crosslinkable group, the dichroic substance can be fixed in a predetermined orientation state when the optically absorptive anisotropic layer is formed using the composition for forming an optically absorptive anisotropic layer. Specific examples of the crosslinkable group include a (meth)acryloyl group, an epoxy group, an oxetanyl group, and a styryl group, and among these, a (meth)acryloyl group is preferred.

[0043] The content of the dichroic material in the optically absorptive anisotropic layer is not particularly limited, and is often 5.0% by mass or more relative to the total mass of the optically absorptive anisotropic layer. In terms of making the projected image more visible (hereinafter also simply referred to as "the point where the effect of the present invention is better"), it is preferably 10.0% by mass or more, more preferably 13.0 to 35.0% by mass, and even more preferably 17.0 to 30.0% by mass.

[0044] [Liquid crystal compound] The light absorption anisotropic layer preferably contains a liquid crystal compound, which can align the dichroic material with a higher degree of orientation while preventing precipitation of the dichroic material. As the liquid crystal compound, either a polymer liquid crystal compound or a low molecular weight liquid crystal compound can be used, and a polymer liquid crystal compound is preferred from the viewpoint of achieving a high degree of orientation. Alternatively, as the liquid crystal compound, a polymer liquid crystal compound and a low molecular weight liquid crystal compound may be used in combination. Here, the term "polymeric liquid crystal compound" refers to a liquid crystal compound having a repeating unit in its chemical structure. Furthermore, the term "low molecular weight liquid crystal compound" refers to a liquid crystal compound that does not have a repeating unit in its chemical structure. Examples of the polymer liquid crystal compound include the thermotropic liquid crystalline polymer described in JP 2011-237513 A and the polymer liquid crystal compound described in paragraphs

[0012] to

[0042] of WO 2018 / 199096 A. Examples of low molecular weight liquid crystal compounds include the liquid crystal compounds described in paragraphs

[0072] to

[0088] of JP 2013-228706 A, and among them, liquid crystal compounds exhibiting smectic properties are preferred.

[0045] The liquid crystal compound is preferably a polymer liquid crystal compound containing a repeating unit represented by the following formula (1) (hereinafter also abbreviated as "repeating unit (1)"), since this increases the degree of orientation of the dichroic material.

[0046] [ka]

[0047] In the above formula (1), P1 represents the main chain of the repeating unit, L1 represents a single bond or a divalent linking group, SP1 represents a spacer group, M1 represents a mesogenic group, and T1 represents a terminal group.

[0048] Specific examples of the main chain of the repeating unit represented by P1 include groups represented by the following formulae (P1-A) to (P1-D). Among these, the group represented by the following formula (P1-A) is preferred in terms of the variety of monomers that can be used as raw materials and ease of handling.

[0049] [ka]

[0050] In the above formulas (P1-A) to (P1-D), "*" represents the bonding position with L1 in the above formula (1). In the above formulas (P1-A) to (P1-D), R 1 , R 2 , R 3 and R 4 are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms. The alkyl group may be a linear or branched alkyl group, or an alkyl group having a cyclic structure (a cycloalkyl group). The alkyl group preferably has 1 to 5 carbon atoms. The group represented by the above formula (P1-A) is preferably one unit of a partial structure of a poly(meth)acrylic acid ester obtained by polymerization of a (meth)acrylic acid ester. The group represented by the above formula (P1-B) is preferably an ethylene glycol unit formed by ring-opening polymerization of the epoxy group of a compound having an epoxy group. The group represented by the above formula (P1-C) is preferably a propylene glycol unit formed by ring-opening polymerization of the oxetane group of a compound having an oxetane group. The group represented by the formula (P1-D) is preferably a siloxane unit of a polysiloxane obtained by condensation polymerization of a compound having at least one of an alkoxysilyl group and a silanol group. Here, the compound having at least one of an alkoxysilyl group and a silanol group is preferably a compound represented by the formula SiR 14 (OR 15 )2-, wherein R14 is R in (P1-D) 14 is synonymous with R 15 each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

[0051] In the above formula (1), L1 is a single bond or a divalent linking group. The divalent linking group represented by L1 includes -C(O)O-, -O-, -S-, and -C(O)NR 3 -, -SO2-, and -NR 3 R 4 In the formula, R 3 and R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent. When P1 is a group represented by formula (P1-A), L1 is preferably a group represented by -C(O)O-, since this increases the degree of orientation of the dichroic material. When P1 is a group represented by any of the formulae (P1-B) to (P1-D), L1 is preferably a single bond, since this increases the degree of orientation of the dichroic material.

[0052] In the above formula (1), the spacer group represented by SP1 preferably contains at least one structure selected from the group consisting of an oxyethylene structure, an oxypropylene structure, a polysiloxane structure, and a fluorinated alkylene structure, in view of the ease of exhibiting liquid crystallinity and the availability of raw materials. Here, the oxyethylene structure represented by SP1 is *-(CH2-CH2O) n1 A group represented by -* is preferred. In the formula, n1 represents an integer of 1 to 20, and * represents the bonding position with L1 or M1 in the above formula (1). n1 is preferably an integer of 2 to 10, more preferably an integer of 2 to 4, and even more preferably 3, in order to increase the degree of orientation of the dichroic material. In addition, the oxypropylene structure represented by SP1 is *-(CH(CH3)-CH2O) in order to increase the degree of orientation of the dichroic material. n2A group represented by -* is preferred, where n2 represents an integer of 1 to 3, and * represents the bonding position to L1 or M1. In addition, the polysiloxane structure represented by SP1 is *-(Si(CH3)2-O) because it increases the degree of orientation of the dichroic material. n3 A group represented by -* is preferred, where n3 represents an integer of 6 to 10, and * represents the bonding position to L1 or M1. In addition, the fluorinated alkylene structure represented by SP1 is *-(CF2-CF2) because it increases the degree of orientation of the dichroic material. n4 A group represented by -* is preferred, where n4 represents an integer of 6 to 10, and * represents the bonding position to L1 or M1.

[0053] In the above formula (1), the mesogenic group represented by M1 is a group that represents the main skeleton of the liquid crystal molecule that contributes to the formation of liquid crystals. The liquid crystal molecules exhibit liquid crystallinity, which is an intermediate state (mesophase) between the crystalline state and the isotropic liquid state. There are no particular limitations on the mesogenic group, and for example, the mesogenic group can be any of the groups described in "Flussige Kristalle in Tabellen II" (VEB Deutsche Verlag fur Grundstoff Industrie, Leipzig, 1988). For example, see the LCD Handbook (published in 2004), especially pages 7 to 16, and the LCD Handbook (Maruzen, published in 2000), edited by the LCD Handbook Editorial Committee, especially the description in Chapter 3. The mesogenic group is preferably, for example, a group having at least one cyclic structure selected from the group consisting of an aromatic hydrocarbon group, a heterocyclic group, and an alicyclic group. The mesogenic group preferably has an aromatic hydrocarbon group, more preferably has 2 to 4 aromatic hydrocarbon groups, and even more preferably has 3 aromatic hydrocarbon groups, in order to increase the degree of orientation of the dichroic substance.

[0054] As the mesogenic group, from the viewpoints of the expression of liquid crystallinity, adjustment of the liquid crystal phase transition temperature, availability of raw materials and suitability for synthesis, as well as a higher degree of orientation of the dichroic substance, a group represented by the following formula (M1-A) or a group represented by the following formula (M1-B) is preferred, and a group represented by formula (M1-B) is more preferred.

[0055] [ka]

[0056] In formula (M1-A), A1 is a divalent group selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups, and alicyclic groups, which may be substituted with a substituent such as an alkyl group, a fluorinated alkyl group, or an alkoxy group. The divalent group represented by A1 is preferably a 4- to 6-membered ring. The divalent group represented by A1 may be a monocyclic ring or a condensed ring. * indicates the binding position to SP1 or T1.

[0057] Examples of the divalent aromatic hydrocarbon group represented by A1 include a phenylene group, a naphthylene group, a fluorene-diyl group, an anthracene-diyl group, and a tetracene-diyl group. From the viewpoints of the diversity of mesogenic skeleton designs and the availability of raw materials, a phenylene group or a naphthylene group is preferred, and a phenylene group is more preferred.

[0058] The divalent heterocyclic group represented by A1 may be either aromatic or non-aromatic, but is preferably a divalent aromatic heterocyclic group in that it increases the degree of orientation of the dichroic material. Atoms other than carbon that constitute a divalent aromatic heterocyclic group include a nitrogen atom, a sulfur atom, and an oxygen atom. When an aromatic heterocyclic group has multiple atoms that constitute the ring other than carbon, these atoms may be the same or different. Specific examples of the divalent aromatic heterocyclic group include a pyridylene group (pyridine-diyl group), a pyridazine-diyl group, an imidazole-diyl group, a thienylene (thiophene-diyl group), a quinolylene group (quinoline-diyl group), an isoquinolylene group (isoquinoline-diyl group), an oxazole-diyl group, a thiazole-diyl group, an oxadiazole-diyl group, a benzothiazole-diyl group, a benzothiadiazole-diyl group, a phthalimido-diyl group, a thienothiazole-diyl group, a thiazolothiazole-diyl group, a thienothiophene-diyl group, and a thienoxazole-diyl group.

[0059] Specific examples of the divalent alicyclic group represented by A1 include a cyclopentylene group and a cyclohexylene group.

[0060] In formula (M1-A), a1 represents an integer of 1 to 10. When a1 is 2 or more, multiple A1 may be the same or different.

[0061] In formula (M1-B), A2 and A3 each independently represent a divalent group selected from the group consisting of an aromatic hydrocarbon group, a heterocyclic group, and an alicyclic group. Specific examples and preferred embodiments of A2 and A3 are the same as those of A1 in formula (M1-A), and therefore, description thereof will be omitted. In formula (M1-B), a2 represents an integer of 1 to 10. When a2 is 2 or greater, multiple A2s may be the same or different, multiple A3s may be the same or different, and multiple LA1s may be the same or different. a2 is preferably an integer of 2 or greater, and more preferably 2, in order to increase the degree of orientation of the dichroic material. In formula (M1-B), when a2 is 1, LA1 is a divalent linking group. When a2 is 2 or more, the multiple LA1 are each independently a single bond or a divalent linking group, and at least one of the multiple LA1 is a divalent linking group. When a2 is 2, it is preferable that one of the two LA1 is a divalent linking group and the other is a single bond, since this increases the degree of orientation of the dichroic material.

[0062] In formula (M1-B), the divalent linking group represented by LA1 is -O-, -(CH2) g -, -(CF2) g -, -Si(CH3)2-, -(Si(CH3)2O) g -, -(OSi(CH3)2) g -(g represents an integer from 1 to 10.), -N(Z)-, -C(Z)=C(Z')-, -C(Z)=N-, -C(Z)2-C(Z')2-, -C(O)-, -OC(O)-, -OC(O) O-, -N(Z)C(O)-, -C(Z)=C(Z')-C(O)O-, -C(Z)=N-, -C(Z)=C(Z')-C(O)N(Z”)-, -C(Z)=C(Z')-C(O)- Examples include S-, -C(Z)=NN=C(Z')- (Z, Z', and Z" each independently represent a hydrogen atom, a C1-C4 alkyl group, a cycloalkyl group, an aryl group, a cyano group, or a halogen atom), -C≡C-, -N=N-, -S-, -S(O)-, -S(O)(O)-, -(O)S(O)O-, -O(O)S(O)O-, and -SC(O). Of these, -C(O)O- is preferred because it increases the degree of orientation of the dichroic substance. LA1 may be a group combining two or more of these groups.

[0063] In the above formula (1), examples of the terminal group represented by T1 include a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an alkoxycarbonyloxy group having 1 to 10 carbon atoms, an alkoxycarbonyl group having 1 to 10 carbon atoms (ROC(O)-: R is an alkyl group), an acyloxy group having 1 to 10 carbon atoms, an acylamino group having 1 to 10 carbon atoms, an alkoxycarbonylamino group having 1 to 10 carbon atoms, a sulfonylamino group having 1 to 10 carbon atoms, a sulfamoyl group having 1 to 10 carbon atoms, a carbamoyl group having 1 to 10 carbon atoms, a sulfinyl group having 1 to 10 carbon atoms, a ureido group having 1 to 10 carbon atoms, and a (meth)acryloyloxy group-containing group. Examples of the (meth)acryloyloxy group-containing group include a group represented by -LA (L represents a single bond or a linking group. Specific examples of the linking group are the same as those of L1 and SP1 described above. A represents a (meth)acryloyloxy group).

[0064] T1 is preferably an alkoxy group having 1 to 10 carbon atoms, more preferably an alkoxy group having 1 to 5 carbon atoms, and even more preferably a methoxy group, in that the degree of orientation of the dichroic material is increased. These terminal groups may be further substituted with these groups or polymerizable groups described in JP-A-2010-244038.

[0065] T1 is preferably a polymerizable group, since this improves the adhesion to the adjacent layer and improves the cohesive strength of the film. The polymerizable group is not particularly limited, but is preferably a polymerizable group capable of radical polymerization or cationic polymerization. As the radical polymerizable group, a generally known radical polymerizable group can be used, and preferred examples include an acryloyl group or a methacryloyl group. In this case, it is known that the polymerization rate of an acryloyl group is generally fast, and an acryloyl group is preferred from the viewpoint of improving productivity, but a methacryloyl group can also be used as the polymerizable group. As the cationically polymerizable group, a generally known cationically polymerizable group can be used, and specific examples thereof include an alicyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiro orthoester group, and a vinyloxy group. Among these, an alicyclic ether group or a vinyloxy group is preferred, and an epoxy group, an oxetanyl group, or a vinyloxy group is more preferred.

[0066] The weight-average molecular weight (Mw) of the polymer liquid crystal compound containing the repeating unit represented by the above formula (1) is preferably 1,000 to 500,000, more preferably 2,000 to 300,000, in order to increase the degree of orientation of the dichroic material. If the Mw of the polymer liquid crystal compound is within the above range, the polymer liquid crystal compound is easy to handle. In particular, from the viewpoint of suppressing cracks during application, the weight average molecular weight (Mw) of the polymer liquid crystal compound is preferably 10,000 or more, and more preferably 10,000 to 300,000. In addition, from the viewpoint of the temperature latitude of the degree of orientation, the weight average molecular weight (Mw) of the polymer liquid crystal compound is preferably less than 10,000, and more preferably 2,000 or more and less than 10,000. Here, the weight average molecular weight and number average molecular weight in the present invention are values ​​measured by gel permeation chromatography (GPC). Solvent (eluent): N-methylpyrrolidone ·Device name: TOSOH HLC-8220GPC Column: Three TOSOH TSKgel Super AWM-H (6 mm x 15 cm) columns connected together Column temperature: 25℃ Sample concentration: 0.1% by mass ·Flow rate: 0.35mL / min Calibration curve: TOSOH TSK standard polystyrene. Calibration curves are based on seven samples with Mw = 2,800,000 to 1,050 (Mw / Mn = 1.03 to 1.06).

[0067] The liquid crystal compound may be a polymer of a liquid crystal compound having a polymerizable group (polymerizable liquid crystal compound).

[0068] When the optically absorptive anisotropic layer contains a liquid crystal compound, the content of the liquid crystal compound is preferably 50 to 99% by mass, more preferably 75 to 90% by mass, relative to the total mass of the optically absorptive anisotropic layer, in terms of better effects of the present invention.

[0069] [Other ingredients] The optically absorptive anisotropic layer may contain other components in addition to the components described above, such as a vertical alignment agent and a leveling agent.

[0070] Examples of the vertical alignment agent include boronic acid compounds and onium salts. The boronic acid compound is preferably a compound represented by formula (A).

[0071] Formula (A)

[0072] [ka]

[0073] In formula (A), R 1 and R 2 each independently represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. R 3 represents a substituent containing a (meth)acrylic group. Specific examples of the boronic acid compound include the boronic acid compounds represented by general formula (I) described in paragraphs

[0023] to

[0032] of JP-A No. 2008-225281.

[0074] The onium salt is preferably a compound represented by formula (B).

[0075] Formula (B)

[0076] [ka]

[0077] In formula (B), ring A represents a quaternary ammonium ion consisting of a nitrogen-containing heterocycle. - represents an anion. 1 represents a divalent linking group. 2 represents a single bond or a divalent linking group. 1 represents a divalent linking group having a 5- or 6-membered ring as a partial structure. Z represents a divalent linking group having 2 to 20 alkylene groups as a partial structure. P 1 and P 2 each independently represents a monovalent substituent having a polymerizable ethylenically unsaturated bond. Specific examples of the onium salt include the onium salts described in paragraphs

[0052] to

[0058] of JP-A No. 2012-208397, the onium salts described in paragraphs

[0024] to

[0055] of JP-A No. 2008-026730, and the onium salts described in JP-A No. 2002-037777.

[0078] When the optically absorptive anisotropic layer contains a liquid crystal compound and a vertical alignment agent, the content of the vertical alignment agent is preferably 0.1 to 400% by mass, more preferably 0.5 to 350% by mass, based on the total mass of the liquid crystal compound. The vertical alignment agent may be used alone or in combination of two or more. When two or more vertical alignment agents are used, the total amount thereof is preferably within the above range.

[0079] The optically absorptive anisotropic layer may contain a leveling agent. When the optically absorptive anisotropic layer-forming composition (optically absorptive anisotropic layer) described below contains a leveling agent, surface roughness caused by dry air on the surface of the optically absorptive anisotropic layer is suppressed, and the dichroic material is more uniformly oriented. The leveling agent is not particularly limited, and is preferably a leveling agent containing a fluorine atom (fluorine-based leveling agent) or a leveling agent containing a silicon atom (silicon-based leveling agent), and more preferably a fluorine-based leveling agent.

[0080] Examples of fluorine-based leveling agents include fatty acid esters of polycarboxylic acids in which a portion of the fatty acid is substituted with a fluoroalkyl group, and polyacrylates having a fluoro substituent.

[0081] Specific examples of the leveling agent include the compounds exemplified in paragraphs

[0046] to

[0052] of JP-A No. 2004-331812 and the compounds described in paragraphs

[0038] to

[0052] of JP-A No. 2008-257205.

[0082] When the light absorption anisotropic layer contains a liquid crystal compound and a leveling agent, the content of the leveling agent is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, based on the total mass of the liquid crystal compound. The leveling agents may be used alone or in combination of two or more. When two or more leveling agents are used, the total amount thereof is preferably within the above range.

[0083] [Composition for forming optically absorptive anisotropic layer] The optically absorptive anisotropic layer is preferably formed using a composition for forming an optically absorptive anisotropic layer that contains a dichroic material. The composition for forming the optically absorptive anisotropic layer preferably contains a liquid crystal compound and a solvent described below in addition to the dichroic material, and may further contain the other components described above.

[0084] The dichroic substance contained in the composition for forming the optically absorptive anisotropic layer includes dichroic substances that can be contained in the optically absorptive anisotropic layer. The content of the dichroic material relative to the total solid mass of the composition for forming the optically absorptive anisotropic layer is preferably the same as the content of the dichroic material relative to the total mass of the optically absorptive anisotropic layer. Here, "total solid content in the composition for forming an optically absorptive anisotropic layer" refers to the components excluding the solvent, and specific examples of the solid content include the dichroic material, the liquid crystal compound, and the other components mentioned above.

[0085] The liquid crystal compound and other components that can be contained in the composition for forming the optically absorptive anisotropic layer are the same as the liquid crystal compound and other components that can be contained in the optically absorptive anisotropic layer, respectively. Examples of the liquid crystal compound include the above-mentioned polymer liquid crystal compound and a liquid crystal compound having a polymerizable group. The content of the liquid crystal compound and other components relative to the total solid mass of the composition for forming the optically absorptive anisotropic layer is preferably the same as the content of the liquid crystal compound and other components relative to the total mass of the optically absorptive anisotropic layer.

[0086] The composition for forming the optically absorptive anisotropic layer preferably contains a solvent from the viewpoint of workability. Examples of the solvent include organic solvents such as ketones, ethers, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated carbons, esters, alcohols, cellosolves, cellosolve acetates, sulfoxides, amides, and heterocyclic compounds, as well as water. These solvents may be used alone or in combination of two or more. Of these solvents, organic solvents are preferred, and halogenated carbons or ketones are more preferred.

[0087] When the composition for forming an optically absorptive anisotropic layer contains a solvent, the content of the solvent is preferably 80 to 99 mass %, more preferably 83 to 97 mass %, and even more preferably 85 to 95 mass %, relative to the total mass of the composition for forming an optically absorptive anisotropic layer.

[0088] The composition for forming the optically absorptive anisotropic layer may contain a polymerization initiator. The polymerization initiator is not particularly limited, but is preferably a photosensitive compound, that is, a photopolymerization initiator. As such a photopolymerization initiator, commercially available products can be used, including Irgacure 184, Irgacure 907, Irgacure 369, Irgacure 651, Irgacure 819, Irgacure OXE-01 and Irgacure OXE-02 manufactured by BASF. The polymerization initiator may be used alone or in combination of two or more kinds. When the composition for forming an optically absorptive anisotropic layer contains a polymerization initiator, the content of the polymerization initiator is preferably 0.01 to 30 mass %, more preferably 0.1 to 15 mass %, based on the total solid content of the composition for forming an optically absorptive anisotropic layer.

[0089] [Method for manufacturing optically absorptive anisotropic layer] The method for producing the optically absorptive anisotropic layer is not particularly limited, but from the viewpoint of achieving a higher degree of orientation of the dichroic material, a method (hereinafter also referred to as "this production method") comprising, in this order, a step of forming a coating film by applying a composition for forming an optically absorptive anisotropic layer containing a dichroic material and a liquid crystal compound onto an alignment film (hereinafter also referred to as "coating film formation step"), and a step of orienting the liquid crystal component contained in the coating film (hereinafter also referred to as "orientation step"). The liquid crystal component includes not only the above-mentioned liquid crystal compounds but also dichroic substances having liquid crystal properties. Each step will be described below.

[0090] The coating film forming step is a step of forming a coating film by applying the above-mentioned composition for forming an optically absorptive anisotropic layer onto an alignment film. By using a composition for forming an optically absorbing anisotropic layer that contains the above-mentioned solvent, or by using a composition for forming an optically absorbing anisotropic layer that has been converted into a liquid such as a molten liquid by heating, it becomes easy to apply the composition for forming an optically absorbing anisotropic layer onto the alignment film. Examples of methods for applying the composition for forming an optically absorptive anisotropic layer include known methods such as roll coating, gravure printing, spin coating, wire bar coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spraying, and inkjet printing.

[0091] The alignment film may be any film that can align the liquid crystal component that can be contained in the composition for forming the light absorption anisotropic layer. This can be achieved by rubbing an organic compound (preferably a polymer) onto the film surface, obliquely vapor-depositing an inorganic compound, forming a layer with microgrooves, or accumulating an organic compound (e.g., ω-tricosanoic acid, dioctadecylmethylammonium chloride, methyl stearate) using the Langmuir-Blodgett method (LB film). Furthermore, alignment films that exhibit alignment function upon application of an electric field, a magnetic field, or light irradiation are also known. Among these, in the present invention, alignment films formed by rubbing are preferred in terms of ease of control of the pretilt angle of the alignment film, and photo-alignment films formed by light irradiation are also preferred in terms of uniformity of alignment.

[0092] As the photo-alignment film, a photo-alignment film containing an azobenzene dye or polyvinyl cinnamate or the like is used. Ultraviolet light is irradiated from an oblique direction at an angle to the normal direction of the photo-alignment layer, generating anisotropy with a tilt relative to the normal direction of the photo-alignment layer, and by orienting an optically absorbing anisotropic layer on top of this, the dichroic material in the optically absorbing anisotropic layer can be aligned. Furthermore, a liquid crystal layer such as a liquid crystal layer in which liquid crystal compounds are hybrid-aligned can also be used as the alignment film.

[0093] The alignment process is a process for aligning the liquid crystal components (especially the dichroic material) contained in the coating film. In the alignment process, it is thought that the dichroic material is oriented along the liquid crystal compound oriented by the alignment film. The orientation step may include a drying treatment. By the drying treatment, components such as the solvent can be removed from the coating film. The drying treatment may be performed by leaving the coating film at room temperature for a predetermined time (for example, natural drying), or by heating and / or blowing air.

[0094] The alignment step preferably includes a heat treatment, which further aligns the dichroic material contained in the coating film, thereby increasing the degree of alignment of the dichroic material. From the viewpoint of manufacturability, the heat treatment temperature is preferably 10 to 250° C., more preferably 25 to 190° C. The heating time is preferably 1 to 300 seconds, more preferably 1 to 60 seconds.

[0095] The orientation step may include a cooling treatment carried out after the heating treatment. The cooling treatment is a treatment in which the coated film after heating is cooled to about room temperature (20 to 25°C). This further fixes the orientation of the dichroic material contained in the coated film, thereby increasing the degree of orientation of the dichroic material. The cooling method is not particularly limited and can be carried out by a known method. By the above steps, the optically absorptive anisotropic layer of the present invention can be obtained.

[0096] The present manufacturing method may include a step of curing the optically absorptive anisotropic layer (hereinafter also referred to as a "curing step") after the above alignment step. The curing step is carried out, for example, by heating and / or light irradiation (exposure), and among these, the curing step is preferably carried out by light irradiation. The light source used for curing can be various light sources such as infrared light, visible light, or ultraviolet light, but ultraviolet light is preferred. Furthermore, ultraviolet light may be irradiated while heating during curing, or ultraviolet light may be irradiated through a filter that transmits only specific wavelengths. The exposure may be carried out in a nitrogen atmosphere. When the curing of the light absorption anisotropic layer proceeds by radical polymerization, the exposure is preferably carried out in a nitrogen atmosphere, since this reduces inhibition of polymerization by oxygen.

[0097] In FIG. 1, the projection light is emitted from the image projection device 12 in an oblique direction, but the present invention is not limited to this. As shown in FIG. 6, the projection light may be emitted from the image projection device 12 in a vertical direction. The image projection system 10B shown in Fig. 6 includes an image projection device 12, a screen 14A, and an optically absorbing anisotropic layer 16B disposed between the image projection device 12 and the screen 14. As shown in Fig. 6, projection light emitted vertically from the image projection device 12 passes through the optically absorbing anisotropic layer 16B and is reflected by the area of ​​the screen 14A that is irradiated with the projection light. As a result, an observer OB can observe a virtual image of the image projected onto the screen 14A. In the optically absorptive anisotropic layer 16B, the central axis of transmittance extends parallel to the direction in which the projection light travels, as indicated by the black arrow in Fig. 6. As a result, the same effect as that of the image projection system 10A shown in Fig. 1 can be obtained.

[0098] <Second embodiment> FIG. 7 shows a schematic diagram of a second embodiment of the image projection system of the present invention. An image projection system 10C shown in FIG. 7 includes an image projection device 12, a screen 14B, and a light-absorbing anisotropic layer 16A. The second embodiment of the image projection system 10C has the same components as the image projection system 10A of the first embodiment described above, except that it has a screen 14B instead of the screen 14A. The same components are given the same symbols and their explanations are omitted, and the following description will mainly focus on the aspects of the screen 14B.

[0099] The screen 14B has a support 30 and a reflective layer 32 disposed on the support 30. The reflective layer 32 has the function of reflecting the projection light emitted from the image projection device 12 . The support 30 and the reflective layer 32 are described in detail below.

[0100] (Support 30) The support 30 is a member that supports the reflective layer 32 . The type of support 30 is not particularly limited, and known supports can be used. A transparent support is particularly preferred. The transparent support refers to a support having a visible light transmittance of 60% or more, preferably 80% or more, and more preferably 90% or more. Examples of the support 30 include a glass substrate and a resin substrate, with a glass substrate being preferred.

[0101] (reflective layer) The configuration of the reflective layer 32 is not particularly limited as long as it has the function of reflecting the projection light emitted from the image projection device 12 . Among these, a cholesteric liquid crystal layer or a multilayer reflective film is preferred as the reflective layer 32 in terms of achieving a more excellent effect of the present invention.

[0102] The cholesteric liquid crystal layer is a layer in which a cholesteric liquid crystal phase is fixed. The cholesteric liquid crystal phase has wavelength selective reflectivity, which shows selective reflectivity at a specific wavelength. The central wavelength λ of selective reflection of a cholesteric liquid crystal phase (selective reflection central wavelength λ) depends on the pitch P (= helical period) of the helical structure in the cholesteric liquid crystal phase, and follows the relationship λ = n × P with the average refractive index n of the cholesteric liquid crystal phase. Therefore, the selective reflection central wavelength can be adjusted by adjusting the pitch of this helical structure. The pitch of a cholesteric liquid crystal phase depends on the type of chiral agent used together with the liquid crystal compound or its concentration, so the desired pitch can be obtained by adjusting these. Furthermore, the half-width Δλ (nm) of the selective reflection band (circularly polarized light reflection band) exhibiting selective reflection depends on the refractive index anisotropy Δn of the cholesteric liquid crystal phase and the helical pitch P, and follows the relationship Δλ = Δn × P. Therefore, the width of the selective reflection band can be controlled by adjusting the refractive index anisotropy Δn of the cholesteric liquid crystal phase. The refractive index anisotropy Δn can be adjusted by the type and mixing ratio of the liquid crystal compounds forming the reflective layer 32, as well as the temperature at which the orientation is fixed. The sense and pitch of the helix can be measured using the methods described in "Introduction to Liquid Crystal Chemistry Experiments," edited by the Japanese Liquid Crystal Society, published by Sigma Publishing in 2007, page 46, and "Liquid Crystal Handbook," published by the Liquid Crystal Handbook Editorial Committee, Maruzen, page 196.

[0103] The reflected light from a cholesteric liquid crystal phase is circularly polarized light. Whether the reflected circularly polarized light is right-handed or left-handed depends on the twist direction of the helix of the cholesteric liquid crystal phase. When the twist direction of the helix of the cholesteric liquid crystal phase is right-handed, the cholesteric liquid crystal phase reflects right-handed circularly polarized light, and when the twist direction of the helix is ​​left-handed, the cholesteric liquid crystal phase reflects left-handed circularly polarized light. The reflective layer 32 may be a cholesteric liquid crystal layer that reflects right-handed circularly polarized light or a cholesteric liquid crystal layer that reflects left-handed circularly polarized light. Alternatively, the reflective layer 32 may include a reflective layer made of a cholesteric liquid crystal layer that reflects right-handed circularly polarized light and a reflective layer made of a cholesteric liquid crystal layer that reflects left-handed circularly polarized light. The direction of rotation of the cholesteric liquid crystal phase can be adjusted by the type of liquid crystal compound forming the reflective layer 32 and / or the type of chiral agent added.

[0104] The wavelength range of reflected light, i.e., the wavelength range of blocked light, can be widened by sequentially stacking layers with shifted selective reflection center wavelengths λ. Also known is a technique for widening the wavelength range by gradually changing the helical pitch within a layer, known as the pitch gradient method, and specific examples include the methods described in Nature 378, 467-469 (1995), JP-A-6-281814, and JP-A-4990426.

[0105] The structure in which the cholesteric liquid crystal phase is fixed may be any structure in which the orientation of the liquid crystal compound in the cholesteric liquid crystal phase is maintained. Typically, the polymerizable liquid crystal compound is brought into an oriented state of the cholesteric liquid crystal phase, and then polymerized and hardened by ultraviolet (UV (Ultra Violet)) irradiation or heating to form a non-fluid layer, and at the same time, the structure is changed to a state in which the orientation form does not change due to an external field or external force. In the structure in which the cholesteric liquid crystal phase is fixed, it is sufficient that the optical properties of the cholesteric liquid crystal phase are maintained, and the liquid crystal compound does not need to exhibit liquid crystallinity. For example, a polymerizable liquid crystal compound may be polymerized by a curing reaction and lose its liquid crystallinity.

[0106] An example of a material used to form a cholesteric liquid crystal layer formed by fixing a cholesteric liquid crystal phase is a liquid crystal composition containing a liquid crystal compound, which is preferably a polymerizable liquid crystal compound. The liquid crystal composition containing the liquid crystal compound used to form the cholesteric liquid crystal layer preferably further contains a surfactant. The liquid crystal composition used to form the cholesteric liquid crystal layer may further contain a chiral agent, a polymerization initiator, an alignment agent, etc.

[0107] A multilayer reflective film is a film that has a property of reflecting light in a specific wavelength range, and is made by laminating multiple layers with different refractive indices. The multilayer reflective film is preferably a film in which layers made of a low refractive index material and layers made of a high refractive index material are alternately laminated. Each layer constituting the multilayer reflective film may be an organic layer made of an organic substance, or an inorganic layer made of an inorganic substance.

[0108] When the reflective layer 32 selectively reflects green light and transmits other light, the image projection system 10C displays a green monochrome image. When the reflective layer 32 selectively reflects red light and transmits other light, the image projection system 10C displays a red monochrome image. When the reflective layer 32 selectively reflects blue light and transmits other light, the image projection system 10C displays a blue monochrome image. Furthermore, when a laminate of a green light reflecting layer, a red light reflecting layer, and a blue light reflecting layer is used as the reflective layer 32, the image projection system 10C displays a full-color image.

[0109] 7, the reflective layer 32 is provided on the entire surface of the support 30, but the present invention is not limited to this embodiment, and the reflective layer 32 may be disposed only on a partial area of ​​the surface of the support 30. In particular, it is preferable that the reflective layer 32 is disposed in an irradiation area that is irradiated with the projection light emitted from the image projection device 12. In addition, in Figure 7, a reflective layer 32 is provided on one surface of the support 30, but the present invention is not limited to this embodiment, and the reflective layer 32 may be sandwiched between two supports 30.

[0110] <Third embodiment> FIG. 8 shows a schematic diagram of a third embodiment of the image projection system of the present invention. 8 includes an image projection system 10D including an image projection device 12, a screen 14B, an optically absorbing anisotropic layer 16A, and a B-plate 18. The B-plate 18 is disposed between the image projection device 12 and the screen 14B, and allows projection light to pass through. The third embodiment of the image projection system 10D has the same components as the image projection system 10C of the second embodiment described above, except that it has a B plate 18. The same components are given the same symbols and their descriptions are omitted, and the following description will mainly focus on the aspects of the B plate 18.

[0111] (B Plate 18) The B plates 18 include positive B plates and negative B plates. When the refractive index in the slow axis direction in the film plane (the direction in which the refractive index in the plane is maximum) is nx, the refractive index in the direction perpendicular to the slow axis in the plane is ny, and the refractive index in the thickness direction is nz, a positive B plate satisfies the relationship in formula (1), and a negative B plate satisfies the relationship in formula (2). Equation (1) nz>nx>ny Equation (2) nx>ny>nz The positive B plate has a negative retardation value in the thickness direction, and the negative B plate has a positive retardation value in the thickness direction.

[0112] The in-plane retardation of the B plate 18 at a wavelength of 550 nm is not particularly limited, but is preferably 120 to 300 nm, more preferably 180 to 250 nm, in terms of providing a better effect of the present invention. The absolute value of the retardation in the thickness direction of the B plate 18 at a wavelength of 550 nm is not particularly limited, but is preferably 200 to 380 nm, more preferably 240 to 350 nm, in terms of providing a better effect of the present invention.

[0113] The material that constitutes the B plate 18 is not particularly limited, and may be a layer formed using a liquid crystal compound, or a resin film.

[0114] <Application> The image display system of the present invention can be applied to a variety of uses. For example, there is an in-vehicle head-up display. When the image display system of the present invention is used as an in-vehicle head-up display, it is preferable to use the windshield of the vehicle as the screen. [Example]

[0115] The features of the present invention will be explained in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, treatment details, and treatment procedures shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0116] Example 1 The surface of a cellulose acylate film (40 μm thick TAC substrate; TG40 Fujifilm Corporation) serving as a support was saponified with an alkaline solution, and the following composition for forming a barrier layer and PVA alignment film was applied thereon using a wire bar. The support with the coated film was dried with hot air at 60°C for 60 seconds and then with hot air at 100°C for 120 seconds to form a barrier layer and PVA alignment film, yielding a transparent support with a barrier layer and PVA alignment film. The thickness of the barrier layer and PVA alignment film was 0.5 μm.

[0117] ---------------------------------------------------------------------------------- (Composition for forming a barrier layer and PVA alignment film) ---------------------------------------------------------------------------------- 3.80 parts by mass of the following modified polyvinyl alcohol Initiator Irg2959 0.20 parts by mass ·Water 70 parts by mass Methanol 30 parts by weight ----------------------------------------------------------------------------------

[0118] Modified Polyvinyl Alcohol

[0119] [ka]

[0120] The barrier layer / PVA alignment film was subjected to a rubbing treatment, and the following composition for forming a tilted liquid crystal alignment film was applied thereon with a wire bar. The applied film was then heated with hot air at 120°C for 30 seconds to form a dried film. Thereafter, a high-pressure mercury lamp was used to apply an illuminance of 200 mW / cm. 2 The tilted liquid crystal alignment film was prepared by irradiating the liquid crystal layer with the light for 1 second under the irradiation condition of 1. The film thickness of the tilted liquid crystal alignment film was 0.60 μm.

[0121] ---------------------------------------------------------------------------------- Composition of the composition for forming a tilted liquid crystal alignment film ---------------------------------------------------------------------------------- 9.57 parts by mass of the following low molecular weight liquid crystal compound M-1 Polymerization initiator IRGACUREOXE-02 (BASF) 0.41 parts by mass 0.026 parts by mass of the following surfactant F-1 Cyclopentanone 66 parts by mass Tetrahydrofuran 66 parts by mass ----------------------------------------------------------------------------------

[0122] Low molecular liquid crystal compound M-1

[0123] [ka]

[0124] Surfactant F-1

[0125] [ka]

[0126] The following composition P1 for forming an optically absorptive anisotropic layer was applied to the prepared tilted liquid crystal alignment film using a wire bar, and the applied film was heated with hot air at 120°C for 30 seconds and then cooled to room temperature. Thereafter, it was reheated at 80°C for 60 seconds and cooled to room temperature again. Thereafter, an LED lamp (center wavelength 365nm) was used to apply the composition P1 to the tilted liquid crystal alignment film at an illuminance of 200mW / cm. 2 An optically absorptive anisotropic layer P1 was prepared by irradiation for 1 second under the irradiation conditions of [Irradiation Condition], and an optical film 1 including the optically absorptive anisotropic layer P1 was obtained. The film thickness of the prepared optically absorptive anisotropic layer P1 was 2.1 μm. The content of the dichroic material in the composition P1 for forming an optically absorptive anisotropic layer was 21.7 mass % based on the total solid content of the composition P1 for forming an optically absorptive anisotropic layer.

[0127] ---------------------------------------------------------------------------------- Optically absorptive anisotropic layer-forming composition P1 ---------------------------------------------------------------------------------- ·Dichroic substance D-1 0.74 parts by mass ·Dichroic substance D-2 0.33 parts by mass ·Dichroic substance D-3 1.10 parts by mass ·Polymer liquid crystal compound P-1 4.32 parts by mass ·Low molecular liquid crystal compound M-1 3.17 parts by mass Polymerization initiator IRGACUREOXE-02 (BASF) 0.317 parts by mass Surfactant F-2 0.010 parts by mass Cyclopentanone 51.4 parts by mass Tetrahydrofuran 51.4 parts by mass ----------------------------------------------------------------------------------

[0128] Dichroic substance D-1

[0129] [ka]

[0130] Dichroic substance D-2

[0131] [ka]

[0132] Dichroic substance D-3

[0133] [ka]

[0134] Polymer liquid crystal compound P-1

[0135] [ka]

[0136] Surfactant F-2 [ka]

[0137] The composition for forming a barrier layer and PVA alignment film was applied onto the prepared optically absorptive anisotropic layer P1 using a wire bar and dried for 5 minutes at 80° C. The resulting coating film was then irradiated with an LED lamp (center wavelength 365 nm) at an illuminance of 150 mW / cm in an environment with an oxygen concentration of 100 ppm and a temperature of 60° C. 2A barrier layer was formed on the optically absorptive anisotropic layer P1 by irradiation for 2 seconds under the irradiation conditions of: The barrier layer had a thickness of 1.0 μm.

[0138] The image projection device used was an iPad (registered trademark) MD510 / DA (manufactured by Apple Inc.). The optical film 1 including the optically absorptive anisotropic layer P1 prepared above was attached to an iPad (registered trademark) using an optical pressure-sensitive adhesive. At this time, the optical film 1 was placed so that the direction of the central transmittance axis of the optically absorptive anisotropic layer P1 projected onto the surface of the optically absorptive anisotropic layer P1 was perpendicular to the absorption axis of the viewing-side polarizer of the iPad (registered trademark), and so that the surface of the optical film 1 opposite the support side faced the iPad (registered trademark). Next, as shown in FIG. 1 , an image projection system was fabricated by arranging an image projection device having an optical film 1 including an optically absorptive anisotropic layer P1 disposed on its surface and a screen 1, which was a glass plate. The image projection device was installed horizontally, and the angle (polar angle) between the normal to the surface of the image projection device and the line connecting the center of the transmission window of the image projection device and the center of the area irradiated with projection light on the screen 1 was 27°. The angle between the line connecting the center of the transmission window of the image projection device and the center of the area irradiated with projection light on the screen 1 and the central axis of transmittance of the optically absorptive anisotropic layer P1 was 17°. The central axis of transmittance of the optically absorptive anisotropic layer P1 was tilted further toward the image projection device than the line connecting the center of the transmission window of the image projection device and the center of the area irradiated with projection light on the screen 1, and the angle between the normal to the surface of the image projection device and the central axis of transmittance of the optically absorptive anisotropic layer P1 was 44°. The azimuth angle of the line connecting the center of the transmission window of the image projector and the center of the area irradiated with the projection light on the screen 1 was parallel to the azimuth angle of the central axis of transmittance of the optically absorptive anisotropic layer P1. 1, the central axis of transmittance of the optically absorptive anisotropic layer P1 was directed toward the screen. More specifically, the screen (particularly, the area irradiated with the projection light) was disposed in the direction in which the central axis of transmittance of the optically absorptive anisotropic layer P1 extended. The position of the observer and the position and angle of the screen 1 were adjusted so that the image projected from the center of the image projection device was positioned approximately at the center of the screen 1.

[0139] <Example 2> An image projection system was produced in the same manner as in Example 1, except that the composition for forming an optically absorptive anisotropic layer P2 was used instead of the composition for forming an optically absorptive anisotropic layer P1. The content of the dichroic material in the composition P2 for forming an optically absorptive anisotropic layer was 13.0 mass % relative to the total solid content of the composition P1 for forming an optically absorptive anisotropic layer.

[0140] ---------------------------------------------------------------------------------- Optically absorptive anisotropic layer-forming composition P2 ---------------------------------------------------------------------------------- ·Dichroic substance D-1 0.40 parts by mass ·Dichroic substance D-2 0.18 parts by mass ·Dichroic substance D-3 0.59 parts by mass ·Polymer liquid crystal compound P-1 4.32 parts by mass ·Low molecular liquid crystal compound M-1 3.17 parts by mass Polymerization initiator IRGACUREOXE-02 (BASF) 0.317 parts by mass Surfactant F-2 0.010 parts by mass Cyclopentanone 51.4 parts by mass Tetrahydrofuran 51.4 parts by mass ----------------------------------------------------------------------------------

[0141] Example 3 The surface of a cellulose acylate film (40 μm thick TAC substrate; TG40 Fujifilm Corporation) was saponified with an alkaline solution, and the above-mentioned barrier layer / PVA alignment film-forming composition was applied thereon using a wire bar. The support with the coating formed thereon was dried with hot air at 60°C for 60 seconds and then with hot air at 100°C for 120 seconds to form an alignment film, yielding a TAC film with an alignment film. The thickness of the alignment film was 1 μm.

[0142] On the obtained alignment film, the following composition P3 for forming an optically absorptive anisotropic layer was continuously coated with a wire bar, heated at 120° C. for 60 seconds, and then cooled to room temperature (23° C.). It was then heated at 80°C for 60 seconds and cooled again to room temperature. Then, an LED lamp (center wavelength 365 nm) was used to illuminate the specimen at an intensity of 200 mW / cm 2 The optically absorptive anisotropic layer P3 was formed on the alignment film by irradiating the alignment film with light for 2 seconds under the irradiation conditions of 1. The optically absorptive anisotropic layer P3 had a thickness of 3.5 μm.

[0143] ---------------------------------------------------------------------------------- Optically absorptive anisotropic layer-forming composition P3 ---------------------------------------------------------------------------------- ·Dichroic substance D-1 0.63 parts by mass ·Dichroic substance D-2 0.17 parts by mass ·Dichroic substance D-3 1.13 parts by mass ·Polymer liquid crystal compound P-1 8.18 parts by mass IRGACUREOXE-02 (BASF) 0.16 parts by mass ·Compound E-1 0.12 parts by mass ·Compound E-2 0.12 parts by mass Surfactant F-1 0.005 parts by weight Cyclopentanone 85.00 parts by mass Benzyl alcohol 4.50 parts by mass ----------------------------------------------------------------------------------

[0144] Compound E-1

[0145] [ka]

[0146] Compound E-2

[0147] [ka]

[0148] The following composition for forming a color adjusting layer was continuously applied onto the obtained light absorption anisotropic layer P3 using a wire bar to form a coating film. The support on which the coating film was formed was then dried with hot air at 60°C for 60 seconds and then with hot air at 100°C for 120 seconds to form a color-adjusting layer C1, thereby obtaining an optical film 3 including a light-absorption anisotropic layer P3 and a color-adjusting layer C1. The film thickness of the color-adjusting layer was 0.5 μm. ---------------------------------------------------------------------------------- Color-adjusting layer-forming composition ---------------------------------------------------------------------------------- 3.80 parts by mass of the above modified polyvinyl alcohol ·IRGACURE2959 0.20 parts by mass ·Pigment compound G-1 0.08 parts by mass ·Water 70 parts by mass Methanol 30 parts by weight ----------------------------------------------------------------------------------

[0149] Pigment compound G-1

[0150] [ka]

[0151] Next, optical film 3 was used instead of optical film 1, and optical film 3 was attached to the image projection device according to the same procedure as in Example 1. The central axis of transmittance of optically absorptive anisotropic layer P3 was parallel to the normal direction to the surface of optically absorptive anisotropic layer P3. Next, as shown in Fig. 6, an image projection system was fabricated by arranging an image projection device having an optical film 3 including an optically absorptive anisotropic layer P3 disposed on its surface and a screen 1. The image projection device was installed horizontally, and the angle (polar angle) between the normal to the surface of the image projection device and the line connecting the center of the transmission window of the image projection device and the center of the area irradiated with projection light on the screen 1 was 0°. The line connecting the center of the transmission window of the image projection device and the center of the area irradiated with projection light on the screen 1 was parallel to the central axis of transmittance of the optically absorptive anisotropic layer P1. 6, the central axis of transmittance of the optically absorptive anisotropic layer P1 was directed toward the screen. More specifically, the screen (particularly, the area irradiated with the projection light) was disposed in the direction in which the central axis of transmittance of the optically absorptive anisotropic layer P1 extended. The position of the observer and the position and angle of the screen 1 were adjusted so that the image projected from the center of the image projection device was positioned approximately at the center of the screen 1.

[0152] Example 4 An image projection system was fabricated in accordance with the same procedure as in Example 1, except that the thickness of the tilted liquid crystal alignment film in Example 1 was changed from 0.60 μm to 1.0 μm. In Example 4, the angle (polar angle) formed by the line connecting the center of the transmission window of the image projection device and the center of the area irradiated with projection light on the screen 1 was 28°. The angle formed by the line connecting the center of the transmission window of the image projection device and the center of the area irradiated with projection light on the screen 1 and the central axis of transmittance of the optically absorptive anisotropic layer P1 was 11°. The central axis of transmittance of the optically absorptive anisotropic layer P1 was tilted further toward the image projection device than the line connecting the center of the transmission window of the image projection device and the center of the area irradiated with projection light on the screen 1, and the angle formed by the normal direction to the surface of the image projection device and the central axis of transmittance of the optically absorptive anisotropic layer P1 was 39°. The azimuth angle of the line connecting the center of the transmission window of the image projector and the center of the area irradiated with the projection light on the screen 1 was parallel to the azimuth angle of the central axis of transmittance of the optically absorptive anisotropic layer P1. The transmittance central axis of the optically absorptive anisotropic layer P1 was oriented toward the screen. More specifically, the screen (particularly, the area irradiated with the projection light) was disposed in the direction in which the transmittance central axis of the optically absorptive anisotropic layer P1 extended.

[0153] <Example 5> According to the procedure described in paragraphs 0101 to 0129 of WO2016 / 052367, an optical functional layer HM-1 including a λ / 2 retardation layer, a cholesteric liquid crystal layer 1, a cholesteric liquid crystal layer 2, and a cholesteric liquid crystal layer 3 in this order was produced. The selective reflection center wavelength of the cholesteric liquid crystal layer 1 was 540 nm, the selective reflection center wavelength of the cholesteric liquid crystal layer 2 was 641 nm, and the selective reflection center wavelength of the cholesteric liquid crystal layer 3 was 761 nm. The in-plane retardation of the λ / 2 retardation layer at a wavelength of 550 nm was 276 nm. Using the obtained optical functional layer HM-1, a screen 2 was produced in which the optical functional layer HM-1 was sandwiched between two glass plates according to the procedure described in paragraph 0130 of WO2016 / 052367.

[0154] An image projection system was fabricated in accordance with the same procedure as in Example 4, except that Screen 2 was used instead of Screen 1.

[0155] Example 6 A screen 3 including a multilayer reflective film was produced according to the procedure of Example 1 of JP 2013-054350 A. The multilayer reflective film had a structure in which two layers with different refractive indices were repeatedly stacked. An image projection system was fabricated in accordance with the same procedure as in Example 4, except that Screen 3 was used instead of Screen 1.

[0156] Example 7 As shown in Figure 8, an image projection system was produced in the same manner as in Example 5, except that a B plate made of a cycloolefin resin was placed between the image projection device and the optical film including the light-absorption anisotropic layer in the image projection system. The in-plane retardation of the B plate at a wavelength of 550 nm was 227 nm, and the retardation in the thickness direction at a wavelength of 550 nm was 285 nm.

[0157] <Comparative Example 1> An image projection system was produced in accordance with the same procedure as in Example 1, except that Optical Film 1 was not used.

[0158] <Evaluation> The evaluation image was turned on in the image projection device of the image projection system obtained above, and the ease of visibility of the image displayed on the screen in a dark room was evaluated, while the brightness (nW) near the screen was also evaluated. In the image projection system, the distance between the image projection device and the observer was approximately 650 mm, and the distance between the image projection device and the screen was approximately 350 mm. The brightness near the screen in a dark room was measured at a wavelength of 520 nm using a power meter (VEGA, manufactured by OPHIR) at a position near the screen. The evaluation images consisted of alphabetical characters displayed in RGB colors on a screen, and legibility was evaluated sensorily according to the following criteria. The size of the characters was adjusted to approximately 3 cm on the screen. Five observers were randomly selected, and each person evaluated the images based on the following scale, with the average being the final visibility rating, shown as "Ease of viewing images on the screen" in Table 1. The observers began the actual evaluation task after allowing their eyes to adapt for about 30 minutes in a dark room. 1 point: Very difficult to see 2 points: Difficult to see 3 points average 4 points: Easy to see 5 points: Very easy to see

[0159] In Table 1, "angle X" represents the angle (°) between the central axis of transmittance of the optically absorptive anisotropic layer and the normal direction of the optically absorptive anisotropic layer. "Angle Y" represents the angle (°) formed by the line connecting the center of the transmission window of the image projector and the center of the area irradiated with the projection light on the screen, and the central axis of transmittance of the light-absorbing anisotropic layer. "Content of dichroic material (% by mass)" represents the content (% by mass) of the dichroic material relative to the total mass of the light absorption anisotropic layer.

[0160] [Table 1]

[0161] As shown in Table 1, the image projection system of the present invention exhibited the desired effects. Furthermore, a comparison between Examples 1 and 2 confirmed that a more excellent effect was achieved when the content of the dichroic material was 15% by mass or more relative to the total mass of the light absorption anisotropic layer. Furthermore, a comparison between Examples 1 and 4 confirmed that a more excellent effect was achieved when the angle Y was within 15°. As shown in Examples 5 and 6, it was confirmed that the effect was even better when the screen had a reflective layer. As shown in Example 7, it was confirmed that the effect was even better when the B plate was used. [Explanation of symbols]

[0162] 10A, 10B, 10C, 10D Image projection system 12 Image projection device 14A, 14B screen 16A, 16B Optically absorbing anisotropic layer 18 B Plate 20 Transparent window 22 Irradiation area 30 Support 32 Reflective layer

Claims

1. an image projection device that emits projection light that is linearly polarized; a screen onto which projection light emitted from the image projection device is irradiated; an optically absorbing anisotropic layer disposed between the image projection device and the screen, through which the projection light passes; the light absorption anisotropic layer contains a dichroic material, An image projection system, wherein the central transmittance axis of the optically absorbing anisotropic layer is oriented toward the screen.

2. 2. The image projection system according to claim 1, wherein the area of ​​the screen irradiated with the projection light is in a direction in which the central axis of transmittance of the light-absorbing anisotropic layer extends.

3. 2. The image projection system according to claim 1, wherein an angle formed between a line connecting the center of the transmission window of the image projection device and the center of the irradiation area of ​​the projection light on the screen and the central axis of transmittance of the optically absorbing anisotropic layer is 0 to 30 degrees.

4. the light absorption anisotropic layer contains a dichroic material, 2. The image projection system according to claim 1, wherein the content of the dichroic material is 10.0% by mass or more with respect to the total mass of the light absorption anisotropic layer.

5. The image projection system of claim 1 , wherein the screen includes a reflective layer that reflects the projection light.

6. The image projection system of claim 5 , wherein the reflective layer is a cholesteric liquid crystal layer or a multilayer reflective film.

7. 2. The image projection system according to claim 1, further comprising a B plate disposed between the image projection device and the light-absorbing anisotropic layer, through which the projection light passes.

8. 8. The image projection system according to claim 1, which is used as an in-vehicle head-up display.

9. 9. The image projection system according to claim 8, wherein a windshield of a vehicle is used as the screen.

Images