WO2021131709A1 - Système d'affichage d'image de projection - Google Patents

Système d'affichage d'image de projection Download PDF

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Publication number
WO2021131709A1
WO2021131709A1 PCT/JP2020/045869 JP2020045869W WO2021131709A1 WO 2021131709 A1 WO2021131709 A1 WO 2021131709A1 JP 2020045869 W JP2020045869 W JP 2020045869W WO 2021131709 A1 WO2021131709 A1 WO 2021131709A1
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Prior art keywords
liquid crystal
cholesteric liquid
light
crystal layer
incident
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PCT/JP2020/045869
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English (en)
Japanese (ja)
Inventor
伊吹　俊太郎
誠 加茂
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富士フイルム株式会社
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Priority to JP2021567194A priority Critical patent/JPWO2021131709A1/ja
Publication of WO2021131709A1 publication Critical patent/WO2021131709A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/10—Projectors with built-in or built-on screen

Definitions

  • the present invention relates to a projection type image display system.
  • Patent Document 1 is a display device including an image source that projects image light and a light guide member that guides the image light projected from the image source and reflects it to the observer side.
  • the light guide member is between the first transparent substrate arranged on the observer side, the second transparent substrate arranged on the side opposite to the observer of the first transparent substrate, and the first transparent substrate and the second transparent substrate. At least a part of the image light projected from the image source is directed to the observer side by being arranged between the first transparent substrate and the second transparent substrate and the intermediate layer having a layer thickness formed substantially evenly.
  • a display device comprising a reflective optical sheet is described.
  • the image light is guided by the light guide member and reflected by the optical sheet provided on the light guide member, so that the image light is reflected to the observer side and the image is displayed to the observer. Further, a part of the light incident from the opposite side of the light guide member is transmitted and visually recognized by the observer. Therefore, the observer can visually recognize the background on the other side of the display device and the image projected by the image source in an overlapping manner.
  • an optical sheet that reflects the light guided in the light guide member an optical shape layer in which a plurality of unit optical shapes having an inclined surface are arranged and an inclined surface are formed. It is described that an optical sheet including a reflective layer that reflects a part of the incident light and transmits the other light is used. Further, it is described that a half mirror is used as the reflective layer.
  • the plurality of inclined reflective layers are arranged. That is, in this optical sheet, the reflective layers are formed discontinuously, and a gap is formed between the reflective layers. Therefore, the light incident on the optical sheet is reflected by the plurality of reflective layers and is emitted in a direction other than the direction in which the image is displayed (hereinafter, also referred to as the front direction).
  • An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a projection type image display system capable of suppressing light from escaping from a surface opposite to the image display surface and visually recognizing an image. There is.
  • the present invention has the following configuration.
  • a projection device that emits a linearly polarized projection image
  • a light guide plate that has an incident surface on which the projected image emitted by the projection device is incident and guides the projected image incident from the incident surface. It is provided with an optical element that is arranged on the main surface of the light guide plate and emits an incident projected image from the light guide plate.
  • the optical element has a retardation layer showing a phase difference of ⁇ / 4 wavelength at an angle at which the projected image is incident on the optical element from the light guide plate side, and a diffraction element having circular polarization selectivity in this order.
  • the diffraction element has a cholesteric liquid crystal layer formed by using a liquid crystal compound, and has a cholesteric liquid crystal layer.
  • the arrangement direction of the bright and dark parts derived from the cholesteric liquid crystal phase observed by the scanning electron microscope in the cross section perpendicular to the main surface of the cholesteric liquid crystal layer is inclined with respect to the main surface of the cholesteric liquid crystal layer.
  • Projection type image display system [2] The projection type image display system according to [1], wherein the retardation layer has a ⁇ / 4 plate and a C plate.
  • the direction of the molecular axis of the liquid crystal compound changes while continuously rotating along at least one direction in the plane on at least one main surface of the pair of main surfaces of the cholesteric liquid crystal layer.
  • a projection type image display system capable of suppressing light from escaping from a surface opposite to the image display surface and visually recognizing the image.
  • FIG. 1 It is a figure which conceptually shows another example of a cholesteric liquid crystal layer used as a diffraction element. It is a figure which conceptually shows another example of a cholesteric liquid crystal layer used as a diffraction element. It is a conceptual diagram of an example of an exposure apparatus which exposes an alignment film. It is a perspective view which shows the projection apparatus and a part of a light guide plate in an enlarged manner. It is a figure which shows the example which uses the projection type image display system for a side window. It is a figure which shows the example which uses the projection type image display system for a side window.
  • the numerical range represented by using “-” in the present specification means a range including the numerical values before and after "-” as the lower limit value and the upper limit value.
  • “(meth) acrylate” is a notation representing both acrylate and methacrylate
  • “(meth) acryloyl group” is a notation representing both an acryloyl group and a methacryloyl group.
  • “(Meta) acrylic” is a notation that represents both acrylic and methacryl.
  • “identical” and the like include an error range generally accepted in the technical field.
  • “same” or the like with respect to an angle means that the difference from an exact angle is within a range of less than 5 degrees unless otherwise specified.
  • the difference from the exact angle is preferably less than 4 degrees, more preferably less than 3 degrees.
  • the projection type image display system of the present invention A projection device that emits a linearly polarized projection image, A light guide plate that has an incident surface on which the projected image emitted by the projection device is incident and guides the projected image incident from the incident surface. It is provided with an optical element that is arranged on the main surface of the light guide plate and emits an incident projected image from the light guide plate.
  • the optical element has a retardation layer showing a phase difference of ⁇ / 4 wavelength with respect to the angle of incidence of the projected image on the optical element from the light guide plate side, and a diffraction element having circular polarization selectivity in this order.
  • the diffraction element has a cholesteric liquid crystal layer formed by using a liquid crystal compound, and has a cholesteric liquid crystal layer.
  • the arrangement direction of the bright and dark parts derived from the cholesteric liquid crystal phase observed by the scanning electron microscope in the cross section perpendicular to the main surface of the cholesteric liquid crystal layer is inclined with respect to the main surface of the cholesteric liquid crystal layer. It is a projection type image display system.
  • the application of the projection type image display system of the present invention is not limited, but a preferable example is to project an image on a window of a public facility, a vehicle, or the like. Specifically, it is particularly suitable for applications used in store windows, vehicle windows (automobiles, buses, trains), and the like.
  • FIG. 1 schematically shows an example of the projection type image display system of the present invention.
  • the projection type image display system 10 shown in FIG. 1 includes a projection device 12, a light guide plate 14, and an optical element 16.
  • the optical element 16 is laminated on one main surface 14c of the light guide plate 14.
  • the projection device 12 is arranged so that the light of the image projected into the light guide plate 14 is incident from the end surface (hereinafter, also referred to as an incident surface) 14a of the light guide plate 14.
  • the main surface is the maximum surface of a sheet-like object (plate-like object, film, etc.).
  • the projection device 12 irradiates the projected image with linearly polarized light.
  • the light I 1 emitted from the projection device 12 and incident on the light guide plate 14 from the incident surface 14a is guided through the light guide plate 14 with linearly polarized light.
  • the optical element 16 has a retardation layer 18 and a diffraction element 20.
  • the retardation layer 18 is a retardation layer showing a phase difference of approximately ⁇ / 4 wavelengths at an incident angle of light (light I 1 in FIG. 1) incident on the optical element 16.
  • the retardation layer 18 is arranged so that the slow axis is 45 ° or ⁇ 45 ° (135 °) with respect to the polarization direction of the linearly polarized light so as to convert the incident linearly polarized light I 1 into circularly polarized light. Will be done.
  • the diffraction element 20 is a diffraction element having circular polarization selectivity, and reflects the incident light in a direction different from that of specular reflection.
  • the diffraction element 20 selectively reflects the circularly polarized light converted by the retardation layer 18. That is, the angle of the slow axis of the retardation layer 18 is set to either 45 ° or ⁇ 45 ° (135 °) depending on the circular polarization selectivity of the diffraction element 20.
  • the diffractive element 20 has a cholesteric liquid crystal layer formed by using a liquid crystal compound, and the cholesteric liquid crystal layer is a scanning electron microscope (SEM) in a cross section perpendicular to the main surface of the cholesteric liquid crystal layer.
  • SEM scanning electron microscope
  • the arrangement direction of the bright part and the dark part derived from the cholesteric liquid crystal phase observed in is inclined with respect to the main surface of the cholesteric liquid crystal layer.
  • the arrangement directions of the bright and dark areas observed in the SEM cross section are inclined, the light incident on the cholesteric liquid crystal layer is reflected (diffracted) in a direction different from the specular reflection.
  • the cholesteric liquid crystal layer has circularly polarized light selective reflectivity. That is, the cholesteric liquid crystal layer reflects one circularly polarized light and transmits the other circularly polarized light. Therefore, the cholesteric liquid crystal layer has transparency.
  • the cholesteric liquid crystal layer will be described in detail later.
  • projection-type image display system 10 having such a configuration, incident from the projection device 12 when the light I 1 of the projection image is emitted, the light I 1 of the projected image from the entrance surface 14a of the light guide plate 14 into the light guide plate 14 To do.
  • the light I 1 incident on the light guide plate 14 travels in the light guide plate 14 while being totally reflected by the main surfaces 14b and 14c of the light guide plate, and is incident on the optical element 16.
  • the light I 1 is guided through the light guide plate 14 with linearly polarized light and is incident on the retardation layer 18 of the optical element 16.
  • Retardation layer 18 in order to show a phase difference of about lambda / 4 wavelengths in the incident angle of light I 1, the light I 1 incident on the retardation layer 18 is converted into circularly polarized light.
  • the light converted into circularly polarized light is incident on the diffraction element 20.
  • the diffraction element 20 reflects the incident circularly polarized light in the direction of the other main surface 14b (hereinafter, also referred to as the front direction) of the light guide plate 14 (light I 2 in FIG. 1).
  • the light I 2 reflected by the optical element 16 and traveling in the front direction is emitted from the light guide plate 14 because it is incident on the main surface 14b at an angle deviating from the total reflection condition.
  • the projection type image display system 10 projects the projection image emitted by the projection device 12 onto the optical element 16 to display the projection image. Since the light guide plate 14 and the optical element 16 have transparency, the user U 1 who sees the projection type image display system 10 from the front can see the background and the projection on the back side (optical element 16 side) of the projection type image display system 10. It can be observed in a state where the image overlaps.
  • the projection device 12 emits the projected image with linearly polarized light, guides the inside of the light guide plate 14 with the linearly polarized light, and the retardation layer of the optical element 16. 18 converts linearly polarized light into circularly polarized light, diffracts the circularly polarized light with a diffracting element 20 having circularly polarized light selectivity, and emits a projected image. That is, almost all the linearly polarized light emitted by the projection device 12 is converted into circularly polarized light and diffracted by the diffraction element 20. Therefore, almost all the light emitted by the projection device 12 is emitted in the front direction, and it is possible to suppress the light from escaping to the back surface side, and it is possible to prevent the image from being visually recognized by a person U 2 other than the user.
  • the projection image can be visually recognized by a person inside the vehicle, and the projection image can be visually recognized by a person outside the vehicle. You can prevent it from happening.
  • the projection type image display system of the present invention does not project light (projected image) directly from the projection device onto the optical element, but guides the light to the optical element by using a light guide plate. Therefore, it is possible to prevent the projected light from being reflected on the surface of the optical element and generating hot spots.
  • the light that is not reflected in the front direction by the optical element 16 is totally reflected at the interface, so that the light is not emitted to the outside of the light guide plate 14 and is not emitted to the outside of the light guide plate 14 as it is.
  • the inside of 14 is guided. Therefore, it is possible to suppress the light from being emitted in a direction other than the front direction, and it is possible to prevent the light from being observed by a person other than the user.
  • the projection device emits circularly polarized light, or the light emitted by the projection device is converted into circularly polarized light, and the light guide plate is circularly polarized.
  • the polarization state may be disrupted while total reflection is repeated in the light guide plate. Therefore, the light is incident on the diffraction element as, for example, elliptically polarized light.
  • the circularly polarized light component in the turning direction that does not match the circularly polarized light selectivity of the diffraction element (cholesteric liquid crystal layer) is not reflected, so that the displayed image becomes dark.
  • the projection type image display system of the present invention has a retardation layer between the light guide plate and the diffraction element, and the projection device emits linearly polarized light. Since light is guided through the light guide plate in a linearly polarized state, the polarized state is unlikely to collapse even if total reflection is repeated in the light guide plate. Therefore, the projected image is incident on the optical element as linearly polarized light, and the retardation layer converts the linearly polarized light into circularly polarized light immediately before the light is incident on the diffraction element. Therefore, the light is incident on the diffraction grating in a state of suitable circularly polarized light. As a result, the diffraction element can reflect (diffract) almost all the components of the light emitted by the projection device 12, so that it is possible to prevent the displayed image from becoming dark.
  • the light of the projected image is indicated by an arrow in FIG. 1, the light emitted from the projection device 12 may be planar, and the planar light is inside the light guide plate 14 while maintaining the positional relationship. Is propagated and reflected by the optical element 16. Further, in FIG. 1, for simplification of the drawing, the light guided through the light guide plate 14 is indicated by one arrow directly directed from the projection device 12 to the optical element 16, but the light is inside the light guide plate 14. Is totally reflected on both main surfaces (interfaces) and guided to the optical element 16.
  • the projection type image display system 10 may have a light absorption layer on an end surface of the light guide plate 14 opposite to the incident surface 14a.
  • the light absorption layer absorbs the light reaching the opposite end face, so that no hot spot is generated.
  • the resin may contain a light absorbing material.
  • a light absorbing material For example, when the light to be absorbed is visible light, a colored (particularly black) resin material, paper, an inorganic material, or the like can be used as the absorption layer.
  • the light absorbing material is not limited, and a known light absorbing material can be used depending on the wavelength range to be absorbed.
  • an inorganic pigment such as carbon black or iron black, an organic pigment such as an insoluble azo pigment, or a known light absorber such as a dye such as azo or anthraquinone. it can.
  • the light guide plate 14 has a wedge shape in which the thickness decreases from the incident surface 14a in the traveling direction of the light, but the thickness is not limited to this, and the light is guided to the optical element.
  • a light guide plate having a certain thickness may be used as long as it can be illuminated.
  • the projection type image display system 10 is configured to emit the light of the projected image in a direction substantially perpendicular to the main surface 14b of the light guide plate 14, but the projection is not limited to this.
  • the light of the image may be emitted in an oblique direction with respect to the main surface 14b of the light guide plate 14.
  • the diffraction element 20 is not limited to the configuration having one cholesteric liquid crystal layer, and may be configured to have two or more cholesteric liquid crystal layers having different spiral pitches of the spiral structure of the cholesteric liquid crystal phase.
  • the cholesteric liquid crystal layer has wavelength selectivity according to the spiral pitch of its helical structure. Therefore, when displaying a color image in the projection type image display system 10, the diffraction element 20 is, for example, a cholesteric liquid crystal layer that selectively reflects red light and a cholesteric liquid crystal layer that selectively reflects green light. It may be configured to have three liquid crystal layers, that is, a cholesteric liquid crystal layer that selectively reflects blue light.
  • the diffraction element 20 may have a configuration having two cholesteric liquid crystal layers, or may have a configuration having four or more layers.
  • the diffractive element may have a configuration having a cholesteric liquid crystal layer that reflects light other than visible light such as infrared rays and / or ultraviolet rays in addition to or instead of visible light such as red light, green light and blue light. ..
  • each cholesteric liquid crystal layer may be configured to reflect light other than visible light such as infrared rays and / or ultraviolet rays.
  • the retardation layer 18 a single-layer retardation layer having a phase difference of approximately ⁇ / 4 wavelength at the incident angle of light, that is, a front phase difference of ⁇ / 4 wavelength.
  • the configuration has a layer having a phase difference deviated from the phase difference of the above, but the present invention is not limited to this.
  • the retardation layer 18 has a ⁇ / 4 plate 22 and a C plate 24 so that the phase difference is approximately ⁇ / 4 wavelength at the incident angle of light. You may.
  • a support having a phase difference of about ⁇ / 4 wavelength may be used instead of the retardation layer.
  • the C plate Since the C plate has a polarization axis in the thickness direction, light incident from a direction perpendicular to the C plate is transmitted without giving a phase difference to the polarization component, but light incident from an oblique direction is transmitted. However, a phase difference can be added to the polarization component. Therefore, the Rth (thickness direction retardation) of the C plate may be adjusted so that the total phase difference with the ⁇ / 4 plate becomes ⁇ / 4 wavelength according to the incident angle of light.
  • the projection device is not limited, and various known projection devices (display devices, projectors) used in the projection type image display system and the like can be used.
  • a projection device having a display and a projection lens is exemplified.
  • the display is not limited, and various known displays used for, for example, AR glasses can be used.
  • the display include a liquid crystal display (LCOS: including Liquid Crystal On Silicon), an organic electroluminescence display, and a scanning display using a DLP (Digital Light Processing) or MEMS (Micro Electro Mechanical Systems) mirror. Is exemplified.
  • the projection type image display system is configured to display a multicolor image
  • a display that displays the multicolor image is used as the display.
  • the projection lens is also a known projection lens (colimating lens) used in the projection type image display system and the like.
  • the display image by the projection device that is, the light emitted by the projection device is linearly polarized light. Therefore, the display may be configured to illuminate a linearly polarized image. Alternatively, when the display illuminates an unpolarized image, the projection device may have, for example, a linear polarizing plate.
  • the light guide plate is a known light guide plate that reflects light incident on the inside and guides (propagates) the light.
  • the light guide plate is not limited, and various known light guide plates used in various image display devices can be used. Examples include an acrylic plate made of a transparent acrylic resin and a glass plate.
  • the thickness of the light guide plate is not particularly limited, but 10 mm or less is preferable in consideration of practicality. However, in this case, since the number of reflections inside the light guide plate becomes very large, the reflected light on the optical element increases, and the same image is displayed with a slight deviation. That is, multiple images will be displayed.
  • the angle of the incident projected image is substantially horizontal with respect to the normal of the end face of the light guide plate. That is, it is necessary to make the angle (incident angle) of the light incident on the incident surface 14a of the light guide plate 14 from the projection device 12 smaller.
  • the angle formed by the normal of the incident surface and the center of the incident light is preferably 10 to 0.1 degrees, more preferably 5 to 0.1 degrees, and further 1 to 0.1 degrees. preferable. This reduces the number of reflections inside the light guide plate and eliminates multiple images.
  • the retardation layer is a layer having an in-plane retardation.
  • the retardation layer may have a phase difference of approximately ⁇ / 4 wavelength at the incident angle of light.
  • the retardation layer known ones can be used without limitation. Therefore, the retardation layer may be derived from a polymer or a liquid crystal.
  • the in-plane retardation Re (550) of the retardation layer may be appropriately adjusted so that the phase difference at the incident angle of light is ⁇ / 4 wavelength. Specifically, it is preferably 110 nm to 160 nm, and more preferably 110 nm to 150 nm.
  • the thickness of the retardation layer is not particularly limited, but is preferably 1 ⁇ m to 4 ⁇ m, more preferably 1 ⁇ m to 3 ⁇ m, from the viewpoint of imparting a retardation to light incident from an angle.
  • the retardation layer may be composed of a ⁇ / 4 plate and a C plate.
  • the ⁇ / 4 plate is a known retardation plate that gives ⁇ / 4 an in-plane retardation.
  • the ⁇ / 4 plate is a plate having a function of converting linearly polarized light having a specific wavelength into circularly polarized light (or converting circularly polarized light into linearly polarized light), and has an in-plane retardation Re ( ⁇ ) at a specific wavelength of ⁇ nm.
  • a plate that satisfies Re ( ⁇ ) ⁇ / 4.
  • the ⁇ / 4 plate is preferably a positive A plate.
  • the positive A plate is defined as follows.
  • the positive A plate (positive A plate) has a refractive index of nx in the slow axis direction in the film plane (the direction in which the refractive index in the plane is maximized), and is orthogonal to the slow axis in the plane in the plane.
  • Equation (A1) nx> ny ⁇ nz
  • ⁇ includes not only the case where both are completely the same, but also the case where both are substantially the same. “Substantially the same” means, for example, “ny ⁇ nz” when (ny-nz) ⁇ d (where d is the thickness of the film) is -10 to 10 nm, preferably -5 to 5 nm. include.
  • a positive A plate can be obtained by horizontally orienting a rod-shaped polymerizable liquid crystal compound.
  • Japanese Patent Application Laid-Open No. 2008-225281 and Japanese Patent Application Laid-Open No. 2008-026730 can be referred to.
  • the C plate includes a positive C plate and a negative C plate.
  • the positive C plate is defined as follows.
  • the positive C plate (positive C plate) is represented by the formula (when the refractive index in one direction in the film plane is nx, the refractive index in the direction orthogonal to the nx direction is ny, and the refractive index in the thickness direction is nz). It satisfies the relationship of C1).
  • the positive C plate shows a negative value for Rth. Equation (C1) nx ⁇ ny ⁇ nz
  • Equation (C1) nx ⁇ ny ⁇ nz
  • the above " ⁇ " includes not only the case where both are completely the same, but also the case where both are substantially the same.
  • nx ⁇ ny when (nx ⁇ ny) ⁇ d (where d is the thickness of the film) is -10 nm to 10 nm, preferably -5 nm to 5 nm. include.
  • the positive C plate can be obtained by using a rod-shaped polymerizable liquid crystal compound and vertically orienting it (homeotropic orientation).
  • a rod-shaped polymerizable liquid crystal compound for example, JP-A-2017-187732, JP-A-2016-53709, and JP-A-2015-200861 can be referred to.
  • the negative C plate satisfies the following formula (C2).
  • the negative C plate shows a positive value for Rth. Equation (C2) nz ⁇ nx ⁇ ny
  • the negative C plate is obtained when a liquid crystal compound having negative refractive index anisotropy (for example, discotic liquid crystal) is horizontally oriented, that is, the axis of symmetry is oriented in a direction perpendicular to the film surface. Can be done.
  • the absolute value of the thickness direction retardation (Rth (550)) at the wavelength of 550 nm of the C plate is such that the total phase difference with the ⁇ / 4 plate is ⁇ / 4 wavelength according to the incident angle of light. You just have to adjust.
  • the thickness of the C plate is not particularly limited, but is preferably 0.1 ⁇ m to 2 ⁇ m, more preferably 0.1 ⁇ m to 1 ⁇ m, from the viewpoint of imparting a phase difference to light incident from an angle.
  • the diffractive element has a cholesteric liquid crystal layer formed by using a liquid crystal compound, and the cholesteric liquid crystal layer is a bright part and a dark part derived from the cholesteric liquid crystal phase observed by SEM in a cross section perpendicular to the main surface of the cholesteric liquid crystal layer. Is inclined with respect to the main surface of the cholesteric liquid crystal layer. Since the arrangement directions of the bright and dark areas observed in the SEM cross section are inclined, the light incident on the cholesteric liquid crystal layer is reflected (diffracted) in a direction different from the specular reflection.
  • FIG. 3 is a schematic view showing the orientation state of the liquid crystal compound in the main surface of the cholesteric liquid crystal layer 34 included in the diffraction element.
  • FIG. 4 is a schematic cross-sectional view showing the state of the liquid crystal phase in the cross section perpendicular to the main surface.
  • the main surface of the cholesteric liquid crystal layer 34 will be referred to as an XY plane
  • the cross section perpendicular to the XY plane will be referred to as an XY plane. That is, FIG. 3 corresponds to a schematic view of the XY plane of the cholesteric liquid crystal layer 34
  • FIG. 3 corresponds to a schematic view of the XY plane of the cholesteric liquid crystal layer 34
  • the cholesteric liquid crystal layer shown in FIGS. 3 to 4 is an example in the case where the liquid crystal compound is a rod-shaped liquid crystal compound.
  • the cholesteric liquid crystal layer reflects one circularly polarized light of the selective reflection wavelength and transmits light in the other wavelength range and the other circularly polarized light. Therefore, the diffraction element having the cholesteric liquid crystal layer is a reflection type diffraction element.
  • the diffraction element has a support 30, an alignment film 32, and a cholesteric liquid crystal layer 34.
  • the diffraction element of the example shown in FIG. 4 has a support 30, an alignment film 32, and a cholesteric liquid crystal layer 34, but the present invention is not limited thereto.
  • the diffraction element may have, for example, only the alignment film 32 and the cholesteric liquid crystal layer 34 from which the support 30 has been peeled off after being attached to the light guide plate 14.
  • the diffraction element may have, for example, only the cholesteric liquid crystal layer 34 from which the support 30 and the alignment film 32 have been peeled off after being attached to the light guide plate 14.
  • the support 30 supports the alignment film 32 and the cholesteric liquid crystal layer 34.
  • various sheet-like materials film, plate-like material
  • the support 30 has a transmittance of 50% or more, more preferably 70% or more, and further preferably 85% or more with respect to the corresponding light.
  • the thickness of the support 30 is not limited, and the thickness capable of holding the alignment film 32 and the cholesteric liquid crystal layer 34 may be appropriately set according to the use of the diffraction element, the forming material of the support 30, and the like. ..
  • the thickness of the support 30 is preferably 1 to 2000 ⁇ m, more preferably 3 to 500 ⁇ m, and even more preferably 5 to 250 ⁇ m.
  • the support 30 may be single-layered or multi-layered.
  • Examples of the support 30 in the case of a single layer include a support 30 made of glass, triacetyl cellulose (TAC), polyethylene terephthalate (PET), polycarbonate, polyvinyl chloride, acrylic, polyolefin or the like.
  • Examples of the support 30 in the case of a multi-layer structure include those including any of the above-mentioned single-layer supports as a substrate and providing another layer on the surface of the substrate.
  • an alignment film 32 is formed on the surface of the support 30.
  • the alignment film 32 is an alignment film for orienting the liquid crystal compound 40 in a predetermined liquid crystal alignment pattern when forming the cholesteric liquid crystal layer 34.
  • the orientation of the optical axis 40A (see FIG. 3) derived from the liquid crystal compound 40 changes while continuously rotating along one direction in the plane. It has a liquid crystal orientation pattern. Therefore, the alignment film 32 is formed so that the cholesteric liquid crystal layer 34 can form this liquid crystal alignment pattern.
  • “the direction of the optic axis 40A rotates” is also simply referred to as "the optical axis 40A rotates”.
  • a rubbing-treated film made of an organic compound such as a polymer, an oblique vapor-deposited film of an inorganic compound, a film having a microgroove, and Langmuir of an organic compound such as ⁇ -tricosanoic acid, dioctadecylmethylammonium chloride and methyl stearylate examples thereof include a membrane obtained by accumulating LB (Langmuir-Blodgett) membranes produced by the Brodget method.
  • the alignment film 32 by the rubbing treatment can be formed by rubbing the surface of the polymer layer with paper or cloth several times in a certain direction.
  • Materials used for the alignment film 32 include polyimide, polyvinyl alcohol, polymers having a polymerizable group described in JP-A-9-152509, JP-A-2005-97377, JP-A-2005-99228, and JP-A-2005-99228. , JP-A-2005-128503, the material used for forming the alignment film 32 and the like described in JP-A-2005-128503 is preferable.
  • a so-called photo-alignment film in which a photo-alignable material is irradiated with polarized light or non-polarized light to form an alignment film 32 is preferably used. That is, in the diffraction element, as the alignment film 32, a photoalignment film formed by applying a photoalignment material on the support 30 is preferably used. Polarized light irradiation can be performed from a vertical direction or an oblique direction with respect to the photoalignment film, and non-polarized light irradiation can be performed from an oblique direction with respect to the photoalignment film.
  • Examples of the photoalignment material used for the alignment film that can be used in the present invention include JP-A-2006-285197, JP-A-2007-76839, JP-A-2007-138138, and JP-A-2007-94071. , JP-A-2007-121721, JP-A-2007-140465, JP-A-2007-156439, JP-A-2007-133184, JP-A-2009-109831, Patent No. 3883848 and Patent No. 4151746.
  • the azo compound described in JP-A the aromatic ester compound described in JP-A-2002-229039, the maleimide having the photoorientation unit described in JP-A-2002-265541 and JP-A-2002-317013, and / Alternatively, an alkenyl-substituted nadiimide compound, a photobridgeable silane derivative described in Japanese Patent No. 4205195 and Japanese Patent No. 4205198, a photocrossbable property described in Japanese Patent Application Laid-Open No. 2003-520878, Japanese Patent Application Laid-Open No. 2004-522220, and Japanese Patent No. 4162850.
  • Photodimerizable compounds described in Japanese Patent Application Laid-Open No. -177561 and Japanese Patent Application Laid-Open No. 2014-12823, particularly cinnamate compounds, chalcone compounds, coumarin compounds and the like are exemplified as preferable examples.
  • azo compounds, photocrosslinkable polyimides, photocrosslinkable polyamides, photocrosslinkable polyesters, synnamate compounds, and chalcone compounds are preferably used.
  • the thickness of the alignment film 32 is not limited, and the thickness at which the required alignment function can be obtained may be appropriately set according to the material for forming the alignment film 32.
  • the thickness of the alignment film 32 is preferably 0.01 to 5 ⁇ m, more preferably 0.05 to 2 ⁇ m.
  • the method for forming the alignment film 32 there is no limitation on the method for forming the alignment film 32, and various known methods depending on the material for forming the alignment film 32 can be used. As an example, a method in which the alignment film 32 is applied to the surface of the support 30 and dried, and then the alignment film 32 is exposed with a laser beam to form an alignment pattern is exemplified.
  • FIG. 10 conceptually shows an example of an exposure apparatus that exposes the alignment film 32 to form an alignment pattern.
  • the exposure apparatus 60 shown in FIG. 10 uses a light source 64 provided with a laser 62, a ⁇ / 2 plate 65 for changing the polarization direction of the laser light M emitted by the laser 62, and a laser beam M emitted by the laser 62 as a light beam MA. It includes a polarizing beam splitter 68 that separates the MB into two, mirrors 70A and 70B arranged on the optical paths of the two separated rays MA and MB, respectively, and ⁇ / 4 plates 72A and 72B.
  • the light source 64 emits linearly polarized light P 0 .
  • lambda / 4 plate 72A is linearly polarized light P 0 (the ray MA) to the right circularly polarized light P R
  • lambda / 4 plate 72B is linearly polarized light P 0 (the rays MB) to the left circularly polarized light P L, converts respectively.
  • the support 30 having the alignment film 32 before the alignment pattern is formed is arranged in the exposed portion, and the two light rays MA and the light rays MB are crossed and interfered with each other on the alignment film 32, and the interference light is made to interfere with the alignment film 32. Is exposed to light. Due to the interference at this time, the polarization state of the light applied to the alignment film 32 periodically changes in the form of interference fringes. As a result, an alignment film having an orientation pattern in which the orientation state changes periodically (hereinafter, also referred to as a pattern alignment film) can be obtained.
  • the period of the orientation pattern can be adjusted by changing the intersection angle ⁇ of the two rays MA and MB. That is, in the exposure apparatus 60, in an orientation pattern in which the optical axis 40A derived from the liquid crystal compound 40 continuously rotates along one direction by adjusting the crossing angle ⁇ , the optical axis 40A rotates in one direction. , The length of one cycle in which the optic axis 40A rotates 180 ° can be adjusted.
  • the optical axis 40A derived from the liquid crystal compound 40 is aligned along one direction, as will be described later.
  • the cholesteric liquid crystal layer 34 having a continuously rotating liquid crystal orientation pattern can be formed. Further, the rotation direction of the optical shaft 40A can be reversed by rotating the optical axes of the ⁇ / 4 plates 72A and 72B by 90 °, respectively.
  • the pattern alignment film is a liquid crystal in which the direction of the optical axis of the liquid crystal compound in the liquid crystal layer formed on the pattern alignment film changes while continuously rotating along at least one direction in the plane. It has an orientation pattern that orients the liquid crystal compound so that it becomes an orientation pattern. Assuming that the axis of the pattern alignment film is the axis along the direction in which the liquid crystal compound is oriented, the direction of the alignment axis of the pattern alignment film changes while continuously rotating along at least one direction in the plane. It can be said that it has an orientation pattern.
  • the orientation axis of the pattern alignment film can be detected by measuring the absorption anisotropy. For example, when the pattern alignment film is irradiated with rotating linearly polarized light and the amount of light transmitted through the pattern alignment film is measured, the direction in which the amount of light becomes maximum or minimum gradually changes along one direction in the plane. It changes and is observed.
  • the alignment film 32 is provided as a preferred embodiment and is not an essential constituent requirement.
  • the liquid crystal layer has an optical axis 40A derived from the liquid crystal compound 40. It is also possible to have a configuration having a liquid crystal orientation pattern in which the orientation of the liquid crystal is changed while continuously rotating along at least one direction in the plane. That is, in the present invention, the support 30 may act as an alignment film.
  • a cholesteric liquid crystal layer 34 is formed on the surface of the alignment film 32.
  • the cholesteric liquid crystal layer is a cholesteric liquid crystal layer in which the cholesteric liquid crystal phase is fixed, and the bright part derived from the cholesteric liquid crystal phase and the bright part derived from the cholesteric liquid crystal phase observed by SEM in a cross section perpendicular to the main surface of the cholesteric liquid crystal layer.
  • the arrangement direction of the dark part is inclined with respect to the main surface of the cholesteric liquid crystal layer.
  • the configuration in which the arrangement direction of the bright part and the dark part observed by SEM is inclined is a liquid crystal orientation pattern in which the direction of the optical axis derived from the liquid crystal compound changes while continuously rotating along at least one direction in the plane. Is formed by having.
  • the cholesteric liquid crystal layer 34 has a spiral structure in which liquid crystal compounds 40 are spirally swirled and stacked, similar to the cholesteric liquid crystal layer formed by fixing a normal cholesteric liquid crystal phase.
  • the liquid crystal compound 40 spirally swirling once has a structure in which the liquid crystal compounds 40 are stacked at a plurality of pitches, with the configuration in which the liquid crystal compounds 40 are spirally rotated once (rotated 360 °) and stacked as one spiral pitch.
  • the cholesteric liquid crystal layer in which the cholesteric liquid crystal phase is fixed has wavelength selective reflectivity.
  • the selective reflection wavelength range of the cholesteric liquid crystal layer depends on the length of one spiral pitch described above (pitch P shown in FIG. 5).
  • the diffraction element having such a liquid crystal layer has wavelength selectivity and diffracts light having a predetermined wavelength. Therefore, the wavelength of the light reflected (diffracted) by the diffraction element may be appropriately set in the selective reflection wavelength range of the liquid crystal layer by adjusting the spiral pitch P of the liquid crystal layer.
  • the liquid crystal compounds 40 are arranged along a plurality of array axes D parallel to each other in the XY plane, and the respective array axes D.
  • the orientation of the optic axis 40A of the liquid crystal compound 40 changes while continuously rotating in one direction in the plane along the array axis D.
  • the array axis D is oriented in the X direction.
  • the liquid crystal compounds 40 having the same orientation of the optical axis 40A are oriented at equal intervals.
  • the direction of the optical axis 40A of the liquid crystal compound 40 changes while continuously rotating in one direction in the plane along the array axis D
  • the optical axis 40A and the array axis D of the liquid crystal compound 40 change.
  • the angle formed by the optic axis D differs depending on the position in the direction of the array axis D, and the angle formed by the optic axis 40A and the array axis D gradually changes from ⁇ to ⁇ + 180 ° or ⁇ -180 ° along the array axis D. It means that you are. That is, as shown in FIG. 3, the plurality of liquid crystal compounds 40 arranged along the array axis D change while the optical axis 40A rotates by a constant angle along the array axis D.
  • the difference in angle between the optical axes 40A of the liquid crystal compounds 40 adjacent to each other in the array axis D direction is preferably 45 ° or less, more preferably 15 ° or less, and further preferably a smaller angle. preferable.
  • the optical axis 40A of the liquid crystal compound 40 is intended to be the molecular major axis of the rod-shaped liquid crystal compound.
  • the optical axis 40A of the liquid crystal compound 40 is intended to be an axis parallel to the normal direction of the disk-shaped liquid crystal compound with respect to the disk surface.
  • the optical axis 40A of the liquid crystal compound 40 is 180 ° in the arrangement axis D direction in which the optical axis 40A continuously rotates and changes in the plane.
  • the length of rotation (distance) be the length ⁇ of one cycle in the liquid crystal alignment pattern. That is, the distance between the centers of the two liquid crystal compounds 40 having the same angle with respect to the array axis D direction in the array axis D direction is defined as the length ⁇ of one cycle.
  • the distance between the centers of the two liquid crystal compounds 40 in which the direction of the arrangement axis D and the direction of the optical axis 40A coincide with each other in the direction of the arrangement axis D is the length ⁇ of one cycle. And. In the following description, the length ⁇ of this one cycle is also referred to as "one cycle ⁇ ".
  • the liquid crystal orientation pattern of the cholesteric liquid crystal layer 34 repeats this one cycle ⁇ in one direction in which the direction of the array axis D, that is, the direction of the optic axis 40A is continuously rotated and changed.
  • the liquid crystal compound 40 forming the cholesteric liquid crystal layer 34 is in the direction orthogonal to the arrangement axis D direction (Y direction in FIG. 3), that is, in the Y direction orthogonal to one direction in which the optical axis 40A continuously rotates.
  • the directions of the optical axes 40A are equal.
  • the liquid crystal compound 40 forming the cholesteric liquid crystal layer 34 has the same angle formed by the optical axis 40A of the liquid crystal compound 40 and the arrangement axis D direction in the Y direction.
  • the arrangement direction in which the bright portions 42 and the dark portions 44 are alternately arranged as shown in FIG. 5 is the main.
  • a striped pattern that is inclined at a predetermined angle with respect to the plane (XY plane) is observed.
  • the distance between the adjacent bright portion 42 to the bright portion 42 or the dark portion 44 to the dark portion 44 in the normal direction of the line formed by the bright portion 42 or the dark portion 44 corresponds to 1/2 pitch. That is, as shown by P in FIG. 5, two bright portions 42 and two dark portions 44 correspond to one pitch of the spiral (one winding number of the spiral).
  • the spiral axis derived from the cholesteric liquid crystal phase is perpendicular to the main surface (XY plane), and its reflecting surface is a plane parallel to the main surface (XY plane).
  • the optical axis of the liquid crystal compound is not inclined with respect to the main surface (XY plane).
  • the optic axis is parallel to the main plane (XY plane). Therefore, when the XX plane of the conventional cholesteric liquid crystal layer is observed by SEM, the arrangement direction in which the bright portion and the dark portion are alternately arranged is perpendicular to the main plane (XY plane). Since the cholesteric liquid crystal phase is specularly reflective, for example, when light is incident on the cholesteric liquid crystal layer from the normal direction, the light is reflected in the normal direction.
  • the cholesteric liquid crystal layer 34 having a configuration in which the arrangement directions of the bright part and the dark part are inclined reflects the incident light by tilting it in the arrangement axis D direction with respect to specular reflection.
  • the cholesteric liquid crystal layer 34 has a liquid crystal orientation pattern in which the optical axis 40A changes while continuously rotating along the arrangement axis D direction (a predetermined one direction) in the plane.
  • the cholesteric liquid crystal layer 34 is a cholesteric liquid crystal layer that selectively reflects the right-handed circularly polarized light R R of red light. Therefore, when light is incident on the cholesteric liquid crystal layer 34, the cholesteric liquid crystal layer 34 reflects only right circularly polarized light R R of the red light, and transmits light of other wavelengths.
  • the optical axis 40A of the liquid crystal compound 40 changes while rotating along the array axis D direction (one direction).
  • the liquid crystal orientation pattern formed on the cholesteric liquid crystal layer 34 is a periodic pattern in the arrangement axis D direction. Therefore, the right circularly polarized light R R of the red light incident on the cholesteric liquid crystal layer 34, as shown conceptually in FIG. 6, is reflected (diffracted) in the direction corresponding to the period of the liquid crystal orientation pattern, reflected red right circularly polarized light R R of the light is reflected (diffracted) in a direction inclined to the array axis direction D with respect to the XY plane (major surface of the cholesteric liquid crystal layer).
  • the light reflection direction (diffraction angle) can be adjusted by appropriately setting the arrangement axis D direction, which is one direction in which the optic axis 40A rotates.
  • the reflection direction of the circularly polarized light can be reversed by reversing the rotation direction of the optical axis 40A of the liquid crystal compound 40 toward the arrangement axis D direction. ..
  • the rotation direction of the optical axis 40A toward the arrangement axis D direction is clockwise, and a certain circularly polarized light is reflected by tilting it in the arrangement axis D direction, which is counterclockwise.
  • a certain circularly polarized light is reflected by tilting in the direction opposite to the direction of the array axis D.
  • the reflection direction is reversed depending on the spiral turning direction of the liquid crystal compound 40, that is, the turning direction of the reflected circularly polarized light.
  • the spiral turning direction is twisted to the right
  • the right circularly polarized light is selectively reflected
  • the optical axis 40A has a liquid crystal alignment pattern that rotates clockwise along the arrangement axis D direction to the right. Circularly polarized light is tilted in the D direction of the array axis and reflected.
  • the left circularly polarized light is selectively reflected, and the liquid crystal layer has a liquid crystal orientation pattern in which the optical axis 40A rotates clockwise along the arrangement axis D direction. Reflects the left circularly polarized light tilted in the direction opposite to the arrangement axis D direction.
  • the shorter one cycle ⁇ is, the larger the angle of the reflected light with respect to the incident light. That is, the shorter one cycle ⁇ is, the more the reflected light can be tilted and reflected with respect to the incident light. Therefore, one cycle of the liquid crystal alignment pattern in the liquid crystal layer of each diffraction element may be appropriately set according to the diffraction angle, arrangement, and the like of each diffraction element.
  • the period (1 period ⁇ ) of the diffraction structure of these diffraction elements is preferably 0.1 ⁇ m to 10 ⁇ m, more preferably 0.1 ⁇ m to 1 ⁇ m, further preferably 0.1 ⁇ m to 0.8 ⁇ m, and propagates through the light guide plate by total reflection. From the viewpoint of making the light, the wavelength of the incident light is more preferably ⁇ or less.
  • the liquid crystal compound 40 in the XX plane of the cholesteric liquid crystal layer 34, has an optical axis 40A oriented in parallel with the main plane (XY plane).
  • the liquid crystal compound 40 is oriented with its optical axis 40A inclined with respect to the main plane (XY plane). It may be.
  • the inclination angle (tilt angle) with respect to the main plane (XY plane) of the liquid crystal compound 40 is uniform in the thickness direction (Z direction).
  • the cholesteric liquid crystal layer 34 may have regions in which the tilt angles of the liquid crystal compounds 40 differ in the thickness direction.
  • the optical axis 40A of the liquid crystal compound 40 is parallel to the main surface (the pretilt angle is 0) at the interface on the alignment film 32 side of the cholesteric liquid crystal layer, and the interface on the alignment film 32 side.
  • the tilt angle of the liquid crystal compound 40 increases as the distance from the liquid crystal compound 40 increases in the thickness direction, and then the liquid crystal compound is oriented at a constant tilt angle to the other interface (air interface) side.
  • the cholesteric liquid crystal layer may have a configuration in which the optical axis of the liquid crystal compound has a pretilt angle at one interface of the upper and lower interfaces, and has a configuration having a pretilt angle at both interfaces. May be good. Further, the pretilt angle may be different at both interfaces. Since the liquid crystal compound has a tilt angle (tilt) in this way, the birefringence of the liquid crystal compound that is effective when light is diffracted becomes high, and the diffraction efficiency can be improved.
  • the average angle (average tilt angle) formed by the optical axis 40A of the liquid crystal compound 40 and the main surface (XY plane) is preferably 5 to 80 °, more preferably 10 to 50 °.
  • the average tilt angle can be measured by observing the XX plane of the cholesteric liquid crystal layer 34 with a polarizing microscope. Above all, in the XX plane of the cholesteric liquid crystal layer 34, it is preferable that the optical axis 40A of the liquid crystal compound 40 is inclined or oriented in the same direction with respect to the main plane (XY plane).
  • the tilt angle is a value obtained by measuring the angle formed by the optical axis 40A of the liquid crystal compound 40 and the main surface at any five or more points in the polarization microscope observation of the cross section of the cholesteric liquid crystal layer and arithmetically averaging them. is there.
  • cholesteric liquid crystal layer Light vertically incident on the diffraction element (cholesteric liquid crystal layer) travels diagonally in the cholesteric liquid crystal layer with a bending force applied.
  • a diffraction loss occurs because a deviation from conditions such as a diffraction period originally set so as to obtain a desired diffraction angle with respect to vertical incidence occurs.
  • the liquid crystal compound is tilted, there is an orientation in which a higher birefringence is generated with respect to the orientation in which the light is diffracted, as compared with the case where the liquid crystal compound is not tilted.
  • the effective abnormal light refractive index becomes large, so that the double refractive index, which is the difference between the abnormal light refractive index and the normal light refractive index, becomes high.
  • the direction of the tilt angle according to the target diffraction direction, it is possible to suppress the deviation from the original diffraction condition in that direction, and as a result, a liquid crystal compound having a tilt angle was used. In this case, it is considered that higher diffraction efficiency can be obtained.
  • the tilt angle is controlled by the treatment of the interface of the liquid crystal layer.
  • the tilt angle of the liquid crystal compound can be controlled by performing a pre-tilt treatment on the alignment film. For example, when the alignment film is formed by exposing the alignment film to ultraviolet rays from the front and then diagonally exposing the alignment film, a pretilt angle can be generated in the liquid crystal compound in the cholesteric liquid crystal layer formed on the alignment film. In this case, the liquid crystal compound is pre-tilted in a direction in which the uniaxial side of the liquid crystal compound can be seen with respect to the second irradiation direction.
  • liquid crystal compound in the direction perpendicular to the second irradiation direction does not pre-tilt, there are an in-plane pre-tilt region and a non-pre-tilt region. This is suitable for increasing the diffraction efficiency because it contributes to the highest birefringence in that direction when the light is diffracted in the target direction.
  • an additive that promotes the pretilt angle can be added in the cholesteric liquid crystal layer or the alignment film. In this case, an additive can be used as a factor for further increasing the diffraction efficiency. This additive can also be used to control the pretilt angle of the interface on the air side.
  • the cholesteric liquid crystal layer is in-plane retardation in either the slow phase axis plane or the phase advance axis plane.
  • the direction in which Re is minimized is inclined from the normal direction.
  • the absolute value of the measurement angle formed by the normal in the direction in which the in-plane retardation Re is minimized is 5 ° or more.
  • the liquid crystal compound of the cholesteric liquid crystal layer is inclined with respect to the main surface, and the inclination direction substantially coincides with the bright part and the dark part of the cholesteric liquid crystal layer.
  • the normal direction is a direction perpendicular to the main surface. Since the cholesteric liquid crystal layer has such a configuration, circularly polarized light can be diffracted with higher diffraction efficiency as compared with the cholesteric liquid crystal layer in which the liquid crystal compound is parallel to the main surface.
  • the liquid crystal compound of the cholesteric liquid crystal layer is inclined with respect to the main surface and the inclination direction substantially coincides with the bright part and the dark part
  • the bright part and the dark part corresponding to the reflecting surface and the optical axis of the liquid crystal compound are used.
  • the action of the liquid crystal compound on the reflection (diffraction) of light is increased, and the diffraction efficiency can be improved.
  • the amount of reflected light with respect to the incident light can be further improved.
  • the absolute value of the optical axis tilt angle of the cholesteric liquid crystal layer is preferably 5 ° or more, more preferably 15 ° or more, still more preferably 20 ° or more.
  • the absolute value of the optical axis tilt angle is preferably 5 ° or more, more preferably 15 ° or more, still more preferably 20 ° or more.
  • the shape of the light-dark line composed of the bright portion 42 and the dark portion 44 derived from the cholesteric liquid crystal phase observed by SEM on the XX plane is wavy (wavy structure). It is also possible to use the cholesteric liquid crystal layer of. Since the cholesteric liquid crystal layer having a wavy light and dark line shape can diffuse light, the viewing angle of the image displayed in the projection type image display system can be increased.
  • the cholesteric liquid crystal layer shown in FIG. 9 has the same configuration as the cholesteric liquid crystal layer shown in FIG. 5, except that the shape of the light-dark line composed of the bright portion 42 and the dark portion 44 is wavy. That is, the cholesteric liquid crystal layer shown in FIG. 9 is a layer having a cholesteric liquid crystal structure and having a structure in which the angle formed by the spiral axis and the surface of the reflective layer changes periodically. In other words, the cholesteric liquid crystal layer has a cholesteric liquid crystal structure, and the cholesteric liquid crystal structure gives a striped pattern of bright and dark parts in the cross-sectional view observed by SEM, and the normal and reflective layers of the lines formed by the dark parts. It is a layer in which the angle formed with the surface changes periodically.
  • the wavy structure means that at least one region M in which the absolute value of the inclination angle with respect to the plane of the cholesteric liquid crystal layer is 5 ° or more exists in the continuous line of the bright portion or the dark portion forming the striped pattern, and the region It is a structure in which peaks or valleys with an inclination angle of 0 ° are specified at the positions closest to each other with M in the plane direction.
  • a peak or valley having an inclination angle of 0 ° includes convex and concave points, but if the inclination angle is 0 °, it also includes steps and shelves.
  • a region M in which the absolute value of the inclination angle is 5 ° or more and a mountain or a valley sandwiching the region M are repeated in a plurality of continuous lines in a bright part or a dark part of a striped pattern.
  • the cholesteric liquid crystal layer having a wavy structure can be formed by forming the cholesteric liquid crystal layer on a forming surface that is not subjected to an orientation treatment such as rubbing.
  • the cholesteric liquid crystal layer can be formed by fixing the cholesteric liquid crystal phase in which the liquid crystal compound is oriented in a predetermined orientation state in a layered manner.
  • the structure in which the cholesteric liquid crystal phase is fixed may be a structure in which the orientation of the liquid crystal compound that is the cholesteric liquid crystal phase is maintained, and typically, the polymerizable liquid crystal compound is in the orientation state of the predetermined liquid crystal phase.
  • the structure is polymerized and cured by irradiation with ultraviolet rays, heating, etc.
  • the structure is changed to a state in which the orientation form is not changed by an external field or an external force.
  • 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 have to exhibit liquid crystal properties in the cholesteric liquid crystal layer.
  • the polymerizable liquid crystal compound may lose its liquid crystal property by increasing its molecular weight by a curing reaction.
  • a liquid crystal composition containing a liquid crystal compound can be mentioned.
  • the liquid crystal compound is preferably a polymerizable liquid crystal compound.
  • the liquid crystal composition used for forming the cholesteric liquid crystal layer may further contain a surfactant and a chiral agent.
  • the polymerizable liquid crystal compound may be a rod-shaped liquid crystal compound or a disk-shaped liquid crystal compound.
  • the rod-shaped polymerizable liquid crystal compound include a rod-shaped nematic liquid crystal compound.
  • rod-shaped nematic liquid crystal compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, and alkoxy-substituted phenylpyrimidines.
  • Phenyldioxans, trans, alkenylcyclohexylbenzonitriles and the like are preferably used. Not only low molecular weight liquid crystal compounds but also high molecular weight liquid crystal compounds can be used.
  • the polymerizable liquid crystal compound is obtained by introducing a polymerizable group into the liquid crystal compound.
  • the polymerizable group include an unsaturated polymerizable group, an epoxy group, and an aziridinyl group, and an unsaturated polymerizable group is preferable, and an ethylenically unsaturated polymerizable group is more preferable.
  • the polymerizable group can be introduced into the molecule of the liquid crystal compound by various methods.
  • the number of polymerizable groups contained in the polymerizable liquid crystal compound is preferably 1 to 6, more preferably 1 to 3.
  • Examples of polymerizable liquid crystal compounds include Makromol. Chem. , 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. No.
  • a cyclic organopolysiloxane compound having a cholesteric phase as disclosed in Japanese Patent Application Laid-Open No. 57-165480 can be used.
  • a polymer liquid crystal compound a polymer having a mesogen group exhibiting a liquid crystal introduced at the main chain, a side chain, or both the main chain and the side chain, and a polymer cholesteric having a cholesteryl group introduced into the side chain.
  • Liquid crystals, liquid crystal polymers as disclosed in JP-A-9-133810, liquid crystal polymers as disclosed in JP-A-11-293252, and the like can be used.
  • disk-shaped liquid crystal compound As the disk-shaped liquid crystal compound, for example, those described in JP-A-2007-108732 and JP-A-2010-244038 can be preferably used.
  • the amount of the polymerizable liquid crystal compound added to the liquid crystal composition is preferably 75 to 99.9% by mass, preferably 80 to 99% by mass, based on the solid content mass (mass excluding the solvent) of the liquid crystal composition. It is more preferably mass%, and even more preferably 85-90 mass%.
  • the liquid crystal composition used when forming the liquid crystal layer may contain a surfactant.
  • the surfactant is preferably a compound capable of stably or rapidly functioning as an orientation control agent that contributes to the orientation of the cholesteric liquid crystal phase.
  • examples of the surfactant include silicone-based surfactants and fluorine-based surfactants, and fluorine-based surfactants are preferably exemplified.
  • the surfactant include the compounds described in paragraphs [2002] to [0090] of JP2014-119605A, and the compounds described in paragraphs [0031] to [0034] of JP2012-203237A. , The compounds exemplified in paragraphs [0092] and [093] of JP-A-2005-999248, paragraphs [0076] to [0078] and paragraphs [0083] to [0085] of JP-A-2002-129162. Examples thereof include the compounds exemplified therein, and the fluorine (meth) acrylate-based polymers described in paragraphs [0018] to [0043] of JP-A-2007-272185.
  • the surfactant one type may be used alone, or two or more types may be used in combination.
  • the fluorine-based surfactant the compounds described in paragraphs [2002] to [0090] of JP-A-2014-119605 are preferable.
  • the amount of the surfactant added to the liquid crystal composition is preferably 0.01 to 10% by mass, more preferably 0.01 to 5% by mass, and 0.02 to 1% by mass with respect to the total mass of the liquid crystal compound. Is even more preferable.
  • the chiral agent has a function of inducing a helical structure of a cholesteric liquid crystal phase. Since the twist direction or spiral pitch of the spiral induced by the compound differs depending on the compound, the chiral agent may be selected according to the purpose.
  • the chiral agent is not particularly limited, and is a known compound (for example, Liquid Crystal Device Handbook, Chapter 3, Section 4-3, TN (twisted nematic), STN (Super Twisted Nematic) chiral agent, page 199, Japan Society for the Promotion of Science. (Described in 1989, edited by the 142nd Committee of the Society), isosorbide, isomannide derivatives and the like can be used.
  • the chiral agent generally contains an asymmetric carbon atom, but an axial asymmetric compound or a surface asymmetric compound that does not contain an asymmetric carbon atom can also be used as the chiral agent.
  • Examples of axially asymmetric or surface asymmetric compounds include binaphthyl, helicene, paracyclophane, and derivatives thereof.
  • the chiral agent may have a polymerizable group. When both the chiral agent and the liquid crystal compound have a polymerizable group, the repeating unit derived from the polymerizable liquid crystal compound and the repeating unit derived from the chiral agent are derived by the polymerization reaction between the polymerizable chiral agent and the polymerizable liquid crystal compound.
  • the polymerizable group of the polymerizable chiral agent is preferably a group of the same type as the polymerizable group of the polymerizable liquid crystal compound. Therefore, the polymerizable group of the chiral agent is preferably an unsaturated polymerizable group, an epoxy group or an aziridinyl group, more preferably an unsaturated polymerizable group, and preferably an ethylenically unsaturated polymerizable group. More preferred. Moreover, the chiral agent may be a liquid crystal compound.
  • the chiral auxiliary has a photoisomeric group
  • a pattern of a desired reflection wavelength corresponding to the emission wavelength can be formed by irradiation with a photomask such as active light after coating and orientation.
  • a photomask such as active light after coating and orientation.
  • an isomerization site of a compound exhibiting photochromic properties an azo group, an azoxy group, or a cinnamoyl group is preferable.
  • Specific compounds include JP-A-2002-80478, JP-A-2002-80851, JP-A-2002-179668, JP-A-2002-179669, JP-A-2002-179670, and JP-A-2002.
  • the content of the chiral agent in the liquid crystal composition is preferably 0.01 to 200 mol%, more preferably 1 to 30 mol%, based on the molar content of the liquid crystal compound.
  • the liquid crystal composition contains a polymerizable compound, it preferably contains a polymerization initiator.
  • the polymerization initiator used is preferably a photopolymerization initiator capable of initiating the polymerization reaction by irradiation with ultraviolet rays.
  • photopolymerization initiators include ⁇ -carbonyl compounds (described in U.S. Pat. No. 2,376,661 and U.S. Pat. No. 2,376,670), acidoin ethers (described in U.S. Pat. No. 2,448,828), and ⁇ -hydrogen.
  • Substituted aromatic acidoine compounds (described in US Pat. No. 2722512), polynuclear quinone compounds (described in US Pat. Nos. 3046127 and US Pat. No. 2951758), triarylimidazole dimers and p-aminophenyl ketone. Combinations (described in US Pat. No. 3,549,677), aclysine and phenazine compounds (Japanese Patent Laid-Open No. 60-105667, described in US Pat. No. 4,239,850), and oxadiazole compounds (US Pat. No. 421,970). Description) and the like.
  • the content of the photopolymerization initiator in the liquid crystal composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 12% by mass, based on the content of the liquid crystal compound.
  • the liquid crystal composition may optionally contain a cross-linking agent in order to improve the film strength and durability after curing.
  • a cross-linking agent those that are cured by ultraviolet rays, heat, humidity and the like can be preferably used.
  • the cross-linking agent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a polyfunctional acrylate compound such as trimethylpropantri (meth) acrylate and pentaerythritol tri (meth) acrylate; glycidyl (meth) acrylate.
  • epoxy compounds such as ethylene glycol diglycidyl ether; aziridine compounds such as 2,2-bishydroxymethylbutanol-tris [3- (1-aziridinyl) propionate] and 4,4-bis (ethyleneiminocarbonylamino) diphenylmethane; hexa Isocyanate compounds such as methylene diisocyanate and biuret type isocyanate; polyoxazoline compounds having an oxazoline group in the side chain; and alkoxysilane compounds such as vinyltrimethoxysilane and N- (2-aminoethyl) 3-aminopropyltrimethoxysilane. Can be mentioned.
  • a known catalyst can be used depending on the reactivity of the cross-linking agent, and the productivity can be improved in addition to the improvement of the film strength and durability. These may be used alone or in combination of two or more.
  • the content of the cross-linking agent is preferably 3 to 20% by mass, more preferably 5 to 15% by mass, based on the solid content mass of the liquid crystal composition. When the content of the cross-linking agent is within the above range, the effect of improving the cross-linking density can be easily obtained, and the stability of the liquid crystal phase is further improved.
  • a polymerization inhibitor an antioxidant, an ultraviolet absorber, a light stabilizer, a coloring material, metal oxide fine particles, etc. are added to the liquid crystal composition within a range that does not deteriorate the optical performance and the like. Can be added with.
  • the liquid crystal composition is preferably used as a liquid when forming a cholesteric liquid crystal layer.
  • the liquid crystal composition may contain a solvent.
  • the solvent is not limited and may be appropriately selected depending on the intended purpose, but an organic solvent is preferable.
  • the organic solvent is not limited and may be appropriately selected depending on the intended purpose.
  • a liquid crystal composition is applied to the forming surface of the cholesteric liquid crystal layer, the liquid crystal compound is oriented to a desired liquid state, and then the liquid crystal compound is cured to form a cholesteric liquid crystal layer. It is preferable to do. That is, when forming a cholesteric liquid crystal layer on the alignment film, the liquid crystal composition is applied to the alignment film, the liquid crystal compound is oriented in the state of the cholesteric liquid crystal phase, and then the liquid crystal compound is cured to form the cholesteric liquid crystal phase. It is preferable to form a cholesteric liquid crystal layer formed by fixing the cholesteric liquid crystal layer.
  • printing methods such as inkjet and scroll printing, and known methods capable of uniformly applying the liquid to a sheet-like material such as spin coating, bar coating and spray coating can all be used.
  • the applied liquid crystal composition is dried and / or heated as needed and then cured to form a cholesteric liquid crystal layer.
  • the liquid crystal compound in the liquid crystal composition may be oriented to the cholesteric liquid crystal phase.
  • the heating temperature is preferably 200 ° C. or lower, more preferably 130 ° C. or lower.
  • the oriented liquid crystal compound is further polymerized, if necessary.
  • the polymerization may be either thermal polymerization or photopolymerization by light irradiation, but photopolymerization is preferable.
  • the irradiation energy is preferably 20mJ / cm 2 ⁇ 50J / cm 2, more preferably 50 ⁇ 1500mJ / cm 2.
  • light irradiation may be carried out under heating conditions or a nitrogen atmosphere.
  • the wavelength of the ultraviolet rays to be irradiated is preferably 250 to 430 nm.
  • a composition containing a disk-shaped liquid crystal compound is used to form an inclined liquid crystal layer in which the molecular axis of the disk-shaped liquid crystal compound is inclined with respect to the surface, and the inclined liquid crystal layer is formed.
  • a method of forming a cholesteric liquid crystal layer using a composition containing a liquid crystal compound is also preferably used.
  • a method for forming a cholesteric liquid crystal layer using such a tilted liquid crystal layer is described in paragraphs [0049] to [0194] of International Publication 2019/181247.
  • the thickness of the cholesteric liquid crystal layer there is no limit to the thickness of the cholesteric liquid crystal layer, and the required light reflectance can be obtained depending on the application of the diffraction element, the light reflectance required for the cholesteric liquid crystal layer, the material for forming the liquid crystal layer, and the like.
  • the thickness to be formed may be set as appropriate.
  • the light of the projected image from the projection device may be incident on the light guide plate from, for example, the ceiling side or the overhead side, or is incident on the light guide plate from the wall surface (side surface) side, based on the standing state of the projection type image display system. It may be incident from the floor surface side.
  • the projection image emitted from the projection device 12 is as shown in FIG. May be configured to be compressed in the thickness direction so as to be incident on the light guide plate 14 from the incident surface 14a.
  • the projected image emitted from the projection device 12 may be enlarged in the width direction orthogonal to the thickness direction and incident on the light guide plate 14 from the incident surface 14a.
  • a lens that converges or diffuses light may be used as a method of compressing and / or enlarging the projected image in the thickness direction.
  • a plurality of projection devices may be arranged in the width direction of the incident surface of the light guide plate, and the projection images emitted by the plurality of projection devices may be combined and displayed as one image. ..
  • the projection type image display system can be used for displaying an image on a window glass of an automobile or the like as a light guide plate.
  • the projection device 12 is arranged on the window frame, the projection image is incident on the window glass which is the light guide plate 14, and the optical element 16 is attached to the window glass.
  • the image is displayed at the position of, so that the light guide from the projection device 12 to the light guide plate 14 is established when the window glass is closed, and from the projection device 12 to the light guide plate 14 when the window glass is open.
  • the projection device 12 main body is placed at an arbitrary position in the vehicle of the automobile. It may be installed in (for example, in a trunk), and the light emitted by the projection device 12 may be guided to the window glass by the optical fiber 100.
  • Example 1 ⁇ Manufacturing of diffraction element> (Chiral auxiliary compound CD-1)
  • Compound CD-1 was synthesized by a general method according to the following synthesis procedure.
  • Compound CD-1 is a chiral agent whose spiral direction is to the left and whose spiral-inducing force does not change due to temperature change or light irradiation.
  • Disc-shaped liquid crystal compound D-1 As the disk-shaped liquid crystal compound, the following disk-shaped liquid crystal compound D-1 described in JP-A-2007-131765 was used.
  • Surfactant S-1 is a compound described in Japanese Patent No. 5774518 and has the following structure.
  • the cholesteric liquid crystal layer G1 having a fixed cholesteric orientation state was obtained by irradiating UV (ultraviolet rays) at an irradiation amount of 500 mJ / cm 2 at 30 ° C. and a nitrogen atmosphere to carry out a polymerization reaction of the liquid crystal compound. Obtained.
  • the reflection center wavelength was 550 nm.
  • an optical laminate 1 having a tilted liquid crystal layer 1 and a cholesteric liquid crystal layer G1 arranged on the tilted liquid crystal layer 1 was produced.
  • the cholesteric liquid crystal layer G1 reflects left circularly polarized light.
  • the light receiving angle is the normal direction of the film, with the cholesteric liquid crystal layer G1 side of the optical laminate 1 as the reflecting surface.
  • the polar angle dependence of the measured light incident angle was measured while being fixed at.
  • the wavelength of the incident light was 550 nm.
  • the reflected light intensity on the light receiving side was measured by changing the polar angle in a plane including the direction in which the substrate with the alignment film was rubbed (longitudinal direction of the substrate).
  • the optical grating 1 acts as a diffractive element that reflects the incident light in a direction different from that of specular reflection.
  • the measured light incident angle is fixed while maintaining the incident angle at which the reflected light intensity of the specular reflected light in the normal direction is the maximum value, and the light receiving angle on the light receiving side is set.
  • the polar dependence was measured.
  • the absolute value of the angle difference with respect to the normal direction is 2 degrees or more, it is assumed that there is diffuse reflection property. Confirmed that the absolute value of the difference between the light receiving angles at which the reflected light intensity of the positively reflected light is halved from the maximum value is 2 degrees or more, and that it exhibits diffuse reflectance.
  • a cholesteric liquid crystal layer with a non-uniform spiral axis is formed in the main plane, which is presumed to be the main cause of diffuse reflectance.
  • the pitch of the bright part and the dark part was 365 nm.
  • the reflected light intensity was the strongest when the measured light incident angle was about 45 to 50 degrees, so the incident light was directed in a direction different from specular reflection. It was confirmed that it acts as a diffusing element that reflects light. It was also confirmed that it exhibits diffuse reflectance. Further, from the analysis of the same cross-sectional SEM image as described above, it was confirmed that the tilt angle of the bright and dark parts of the cholesteric liquid crystal layer B1 was 15 degrees and the pitch was 290 nm, and the tilt angle of the bright and dark parts of the cholesteric liquid crystal layer R1 was 15 degrees and the pitch was 430 nm. ..
  • An optical element was prepared by laminating a positive C plate, a ⁇ / 4 plate, a cholesteric liquid crystal layer R1, a cholesteric liquid crystal layer G1, and a cholesteric liquid crystal layer B1 via an adhesive (SK adhesive, manufactured by Soken Kagaku) in the order of lamination.
  • the glass substrate was peeled off and bonded to each cholesteric liquid crystal layer.
  • the laminate of the positive C plate and the ⁇ / 4 plate shows a phase difference of ⁇ / 4 wavelength at an angle (about 30 °) at which the light guided through the light guide plate is incident. That is, the laminated body of the positive C plate and the ⁇ / 4 plate corresponds to a retardation layer showing a phase difference of ⁇ / 4 wavelength at an angle at which light is incident.
  • the positive C plate and the ⁇ / 4 plate were prepared as follows.
  • a coating liquid 1 for a photoalignment film was prepared and coated on a cellulose acylate film Z-TAC (manufactured by FUJIFILM) with a wire bar. Then, the obtained cellulose acylate film was dried with warm air at 60 ° C. for 60 seconds to prepare a coating film 1 having a thickness of 300 nm.
  • composition A1 for forming a ⁇ / 4 plate having the following composition was prepared.
  • ⁇ Composition of composition A1 for forming ⁇ / 4 plate ⁇ -The following polymerizable liquid crystal compound X-1 16.00 parts by mass-The following specific liquid crystal compound L-1 42.00 parts by mass-The following specific liquid crystal compound L-2 42.00 parts by mass-The following polymerization initiator S-1 0. 50 parts by mass, the following polymerizable compound B-1 2.00 parts by mass, the leveling agent (the following compound T-1) 0.20 parts by mass, methyl ethyl ketone (solvent) 230.00 parts by mass, cyclopentanone (solvent) 70. 00 parts by mass ⁇
  • each repeating unit in compound T-1 represents the content (mass%) of each repeating unit with respect to all the repeating units.
  • the prepared coating film 1 was irradiated with ultraviolet rays in the atmosphere using an ultra-high pressure mercury lamp.
  • a wire grid polarizer (ProFlux PPL02 manufactured by Moxtek) was set so as to be parallel to the surface of the coating film 1 and exposed, and photoalignment treatment was performed to obtain a photoalignment film 1.
  • the illuminance of the ultraviolet rays was set to 10 mJ / cm 2 in the UV-A region (ultraviolet A wave, integration of wavelengths of 320 to 380 nm).
  • the composition A1 for forming a ⁇ / 4 plate was applied onto the photoalignment film 1 using a bar coater.
  • the obtained coating film is heat-aged at a film surface temperature of 100 ° C. for 20 seconds, cooled to 90 ° C., and then exposed to ultraviolet rays of 300 mJ / cm 2 using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) under air.
  • the ⁇ / 4 plate A1 was formed by immobilizing the nematic orientation state, and an optical film L containing the ⁇ / 4 plate A1 was produced.
  • the formed ⁇ / 4 plate A1 had a film thickness of 2.5 ⁇ m.
  • Re (550) of ⁇ / 4 plate A1 is 145 nm, Rth (550) is 73 nm, Re (550) / Re (450) is 1.13, Re (650) / Re (550) is 1.01, optical axis.
  • the tilt angle of was 0 °, and the liquid crystal compound had a homogeneous orientation.
  • composition C-1) ⁇ -The following forward-dispersible rod-shaped liquid crystal compound (M-1) 83 parts by mass-The following forward-dispersible rod-shaped liquid crystal compound (M-2) 15 parts by mass-The following forward-dispersible rod-shaped liquid crystal compound (M-3) 2 parts by mass Part-The following compound B1 4.5 parts by mass-The following polymerization initiator (IrgacureOXE01, manufactured by BASF) 5 parts by mass, Viscote # 360 (manufactured by Osaka Organic Chemical Industry Co., Ltd.) 8 parts by mass, the following surfactant (T-2) 0.3 parts by mass, the following surfactant (T-3) 0.5 parts by mass, The following onium compound S01 2.0 parts by mass, acetone 229.6 parts by mass, propylene glycol monomethyl ether acetate 42.0 parts by mass, methanol 8.4 parts by mass ⁇ ⁇
  • Surfactant T-2 (Mw: 15k. In the formula, the numerical value described in each repeating unit represents the content (mass%) of each repeating unit with respect to all repeating units.)
  • Surfactant T-3 weight average molecular weight: 11,200 (The numerical value described in each repeating unit represents the content (mass%) of each repeating unit with respect to all the repeating units.)
  • a transparent and flat acrylic plate having a thickness of 25 mm and a main surface size of 150 mm ⁇ 150 mm was used as the sheet-shaped light guide plate.
  • An optical element was attached to one main surface of the acrylic plate with the positive C plate side facing the acrylic plate via an adhesive.
  • the size of the optical element to be bonded was 100 mm ⁇ 100 mm.
  • each cholesteric liquid crystal layer was adjusted and arranged so as to be parallel to the vertical direction. Further, the ⁇ / 4 plate was arranged by adjusting the angle of the slow axis to 45 ° with respect to the vertical direction of the light guide plate so as to convert the incident linearly polarized light (p-polarized light) into left circularly polarized light.
  • the main surface of the light guide plate is installed so as to be perpendicular to the floor surface, and a projector (AXJ800, manufactured by AIRXEL) is used as a projection device on the lower end surface (incident surface) of the acrylic plate which is the light guide plate in the vertical direction. ) was placed. Further, a linear polarizing plate was arranged between the projector and the light guide plate so that the projected image of p-polarized light was incident on the light guide plate. From the above, a projection type image display system was produced.
  • p-polarized light is linearly polarized light that vibrates in the width direction of the light guide plate with respect to the incident surface of the light guide plate
  • s-polarized light is linearly polarized light that vibrates in the thickness direction of the light guide plate
  • Example 2 ⁇ Support with orientation layer> On a triacetyl celllate support (manufactured by Fujifilm Corporation, TG40), the alignment layer coating liquid Y1 having the following composition was applied with a wire bar coater of # 3.6. Then, it was dried at 45 ° C. for 60 seconds and irradiated with ultraviolet rays of 500 mJ / cm 2 at 25 ° C. by an ultraviolet irradiation device to prepare a support with an alignment layer Y1.
  • composition of alignment layer coating liquid Y1 ⁇ ⁇ KAYARAD PET30 (manufactured by Nippon Kayaku Co., Ltd.) 100 parts by mass ⁇ IRGACURE 907 (manufactured by BASF Co., Ltd.) 3.0 parts by mass ⁇ Kayacure DETX (manufactured by Nippon Kayaku Co., Ltd.) 1.0 parts by mass ⁇ Fluorine System horizontal alignment agent F1 0.01 part by mass, methyl isobutyl ketone 243 parts by mass ⁇ ⁇
  • Fluorine-based horizontal alignment agent F1 Fluorine-based horizontal alignment agent
  • Example 1 instead of the rectangular glass substrate (12 ⁇ 15 cm) coated with polyimide SE-130 (manufactured by Nissan Chemical Industries, Ltd.), the support with the orientation layer Y1 was used, and the support was rubbed in the longitudinal direction.
  • the reflection anisotropy and diffuse reflectance were confirmed in the same manner as in Example 1, when the measured light incident angle was about 45 to 50 degrees, the reflected light intensity at the light receiving angle in the normal direction of the optical laminate 1 was the highest. Since it becomes stronger, it was confirmed that it acts as a diffusing element that reflects the incident light in a direction different from the normal reflection. It was also confirmed that it exhibits diffuse reflectance. Further, from the analysis of the cross-sectional SEM image similar to that of Example 1, it was confirmed that the inclination angle of the bright part and the dark part of the cholesteric liquid crystal layer G1 was 15 degrees and the pitch was 365 nm.
  • the reflected light intensity was the strongest when the measured light incident angle was about 45 to 50 degrees, so the incident light was directed in a direction different from specular reflection. It was confirmed that it acts as a diffusing element that reflects light. It was also confirmed that it exhibits diffuse reflectance. Further, from the analysis of the same cross-sectional SEM image as described above, it was confirmed that the tilt angle of the bright and dark parts of the cholesteric liquid crystal layer B1 was 15 degrees and the pitch was 290 nm, and the tilt angle of the bright and dark parts of the cholesteric liquid crystal layer R1 was 15 degrees and the pitch was 430 nm. ..
  • An optical element was prepared by laminating a positive C plate, a ⁇ / 4 plate, a cholesteric liquid crystal layer R1, a cholesteric liquid crystal layer G1, and a cholesteric liquid crystal layer B1 via an adhesive (SK adhesive, manufactured by Soken Kagaku) in the order of lamination.
  • the glass substrate was peeled off and bonded to each cholesteric liquid crystal layer.
  • An optical element was attached to an acrylic plate in the same manner as in Example 1, and a projector and a linear polarizing plate were placed on the end faces of the light guide plate to fabricate a projection type image display system.
  • Example 3 [Preparation of cholesteric liquid crystal layer]
  • Cholesteric liquid crystal layer composition G2, cholesteric liquid crystal layer composition B2, and cholesteric liquid crystal layer composition R2 were prepared in the same manner as in the case of compound G1.
  • a cholesteric liquid crystal layer G2, a cholesteric liquid crystal layer B2, and a cholesteric liquid crystal layer R2 were produced on the inclined liquid crystal layer 1, respectively.
  • the cholesteric liquid crystal layer G2, the cholesteric liquid crystal layer B2, and the cholesteric liquid crystal layer R2 reflect left circularly polarized light.
  • the reflected light intensity was the strongest when the measured light incident angle was about 45 to 50 degrees, so the incident light was specularly reflected. Was confirmed to act as a diffusing element that reflects in different directions. It was also confirmed that it exhibits diffuse reflectance.
  • the tilt angle of the bright and dark parts of the cholesteric liquid crystal layer G2 is 15 degrees and the pitch is 365 nm
  • the tilt angle of the bright and dark parts of the cholesteric liquid crystal layer B2 is 15 degrees and the pitch is 290 nm
  • the cholesteric liquid crystal It was confirmed that the inclination angle of the bright part and the dark part of the layer R2 was 15 degrees and the pitch was 430 nm.
  • An optical element was prepared by laminating a positive C plate, a ⁇ / 4 plate, a cholesteric liquid crystal layer R2, a cholesteric liquid crystal layer G2, and a cholesteric liquid crystal layer B2 in the order of lamination via an adhesive (SK adhesive, manufactured by Soken Kagaku).
  • the glass substrate was peeled off and bonded to each cholesteric liquid crystal layer.
  • An optical element was attached to an acrylic plate in the same manner as in Example 1, and a projector and a linear polarizing plate were placed on the end faces of the light guide plate to fabricate a projection type image display system.
  • the linear polarizing plate was arranged so that the projected image of s-polarized light was incident on the light guide plate.
  • the ⁇ / 4 plate was arranged by adjusting the angle of the slow axis to 135 ° with respect to the vertical direction of the light guide plate so as to convert the incident linearly polarized light (s-polarized light) into left circularly polarized light.
  • Example 1 A commercially available transparent screen (Kaleido Screen, high-brightness front type, manufactured by JXTG Energy Co., Ltd.) is attached to one main surface of the same acrylic plate as in Example 1 with the reflective surface side of the transparent screen facing the acrylic plate. did.
  • the main surface of the acrylic plate is installed so as to be perpendicular to the floor surface, and a projector (AXJ800, AIRXEL) is installed on the lower end surface (incident surface) of the acrylic plate in the vertical direction as a projection device. ) was placed to create a projection-type image display system.
  • a projector AXJ800, AIRXEL
  • the reflection anisotropy of the transparent screen was measured in the same manner as in Example 1, the angle of the incident light beam having the strongest reflected light intensity in the normal direction was 5 ° or less with respect to the normal direction, and the reflection difference was obtained. There was no direction. On the other hand, it was confirmed that the transparent screen has diffuse reflectance.
  • Example 2 A commercially available transparent screen (Ayami s MRPS-T100AH, transparent rear type, manufactured by Mitsubishi Paper Mills Limited) is attached to one main surface of the same acrylic plate as in Example 1 with the reflective surface side of the transparent screen facing the acrylic plate. It fits.
  • a commercially available transparent screen (Ayami s MRPS-T100AH, transparent rear type, manufactured by Mitsubishi Paper Mills Limited) is attached to one main surface of the same acrylic plate as in Example 1 with the reflective surface side of the transparent screen facing the acrylic plate. It fits.
  • the main surface of the acrylic plate is installed so as to be perpendicular to the floor surface, and a projector (AXJ800, AIRXEL) is installed on the lower end surface (incident surface) of the acrylic plate in the vertical direction as a projection device. ) was placed to create a projection-type image display system.
  • a projector AXJ800, AIRXEL
  • the reflection anisotropy of the transparent screen was measured in the same manner as in Example 1, the angle of the incident light beam having the strongest reflected light intensity in the normal direction was 5 ° or less with respect to the normal direction, and the reflection difference was obtained. There was no direction. On the other hand, it was confirmed that the transparent screen has diffuse reflectance.
  • Projection type image display system 12
  • Projection device 14
  • Light guide plate 14a Incident surface 14b, 14c Main surface
  • Optical element 18
  • Phase difference layer 20
  • C plate 30
  • Support 32
  • Alignment film 34
  • Cholesteric liquid crystal layer 40
  • Compound 40A Optical axis 42
  • Bright part 44
  • Dark part 60
  • Exposure device 62
  • Laser 64 Light source 65 ⁇ / 2 plate
  • Polarization beam splitter 70A, 70B Mirror 72A, 72B ⁇ / 4 plate
  • Optical fiber U 1 User U 2 Non-user I 1 light (linearly polarized light) I 2 light (circularly polarized light) ⁇ 1 cycle
  • D array axis P (helix) pitch R
  • red right circularly polarized light M
  • MA ray MB ray P O linearly polarized light
  • P R right circularly polarized light P L left circularly polarized light

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Polarising Elements (AREA)
  • Liquid Crystal (AREA)

Abstract

L'invention concerne un système d'affichage d'image de projection dans lequel le phénomène d'une image qui est visible, en raison d'une pénétration de la lumière à partir d'une surface sur un côté opposé à une surface d'affichage d'image, est empêché. La présente invention comprend : un dispositif de projection qui émet une image projetée de lumière polarisée linéairement ; une plaque de guidage de lumière qui comprend une face de réception de lumière qui reçoit l'image projetée émise par le dispositif de projection et qui guide l'image projetée reçue à partir de la face de réception de lumière ; et un élément optique qui est disposé sur une surface principale de la plaque de guidage de lumière et émet l'image projetée reçue à partir de la plaque de guidage de lumière. Dans l'ordre à partir du panneau de guidage de lumière, l'élément optique comprend une couche de contraste de phase ayant un contraste de phase de longueur d'onde λ/4 par rapport à l'angle d'incidence de l'image projetée par rapport à l'élément optique et un élément diffractif qui est sélectif vis-à-vis de la lumière polarisée de manière circulaire. L'élément diffractif comprend une couche de cristaux liquides cholestériques formée en utilisant un composé de cristaux liquides. La direction d'agencement de parties brillantes et de parties sombres dérivées de la phase de cristaux liquides cholestériques observées par microscope électronique à balayage dans une section transversale orthogonale à une surface principale de la couche de cristaux liquides cholestériques est inclinée par rapport à la surface principale de la couche de cristaux liquides cholestériques.
PCT/JP2020/045869 2019-12-27 2020-12-09 Système d'affichage d'image de projection WO2021131709A1 (fr)

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WO2023149211A1 (fr) * 2022-02-02 2023-08-10 富士フイルム株式会社 Dispositif d'éclairage embarqué, automobile et élément de diffraction

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JP2013088639A (ja) * 2011-10-19 2013-05-13 Seiko Epson Corp 液晶装置、電子機器および投射型表示装置
WO2019049767A1 (fr) * 2017-09-05 2019-03-14 富士フイルム株式会社 Unité de projection
JP2019132902A (ja) * 2018-01-29 2019-08-08 大日本印刷株式会社 表示装置、移動体、照明装置および反射板
WO2019189586A1 (fr) * 2018-03-29 2019-10-03 富士フイルム株式会社 Élément optique

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JP7030847B2 (ja) * 2017-12-27 2022-03-07 富士フイルム株式会社 光学素子、導光素子および画像表示装置
EP3770657A4 (fr) * 2018-03-23 2021-06-02 FUJIFILM Corporation Couche de cristaux liquides cholestériques, corps stratifié, corps optiquement anisotrope, film réfléchissant, procédé de fabrication de couche de cristaux liquides cholestériques ; moyen de prévention de falsification et procédé de détermination
JP6980901B2 (ja) * 2018-03-29 2021-12-15 富士フイルム株式会社 光学素子、導光素子および画像表示装置

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JP2013088639A (ja) * 2011-10-19 2013-05-13 Seiko Epson Corp 液晶装置、電子機器および投射型表示装置
WO2019049767A1 (fr) * 2017-09-05 2019-03-14 富士フイルム株式会社 Unité de projection
JP2019132902A (ja) * 2018-01-29 2019-08-08 大日本印刷株式会社 表示装置、移動体、照明装置および反射板
WO2019189586A1 (fr) * 2018-03-29 2019-10-03 富士フイルム株式会社 Élément optique

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023149211A1 (fr) * 2022-02-02 2023-08-10 富士フイルム株式会社 Dispositif d'éclairage embarqué, automobile et élément de diffraction

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