WO2017138442A1 - Mirror display - Google Patents

Mirror display Download PDF

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Publication number
WO2017138442A1
WO2017138442A1 PCT/JP2017/003891 JP2017003891W WO2017138442A1 WO 2017138442 A1 WO2017138442 A1 WO 2017138442A1 JP 2017003891 W JP2017003891 W JP 2017003891W WO 2017138442 A1 WO2017138442 A1 WO 2017138442A1
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WO
WIPO (PCT)
Prior art keywords
liquid crystal
plate
cholesteric liquid
mirror
display
Prior art date
Application number
PCT/JP2017/003891
Other languages
French (fr)
Japanese (ja)
Inventor
博之 箱井
坂井　彰
箕浦　潔
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シャープ株式会社
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Publication date
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Publication of WO2017138442A1 publication Critical patent/WO2017138442A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/08—Mirrors
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements

Definitions

  • the present invention relates to a mirror display. More specifically, the present invention relates to a mirror display that achieves both a mirror mode that functions as a mirror and a display mode that displays an image.
  • a multilayer reflective polarizing plate or a reflective polarizing plate in which a cholesteric liquid crystal film and a ⁇ / 4 plate are combined has been used.
  • the multilayer reflective polarizing plate has a function of reflecting polarized light in a direction parallel to the reflection axis of incident light and transmitting polarized light in a direction orthogonal to the reflection axis. Therefore, the multilayer reflective polarizing plate can transmit light emitted from the liquid crystal display to the viewer as display light, and can reflect external light in a direction orthogonal to the polarization direction of the display light to the viewer. .
  • a reflective polarizing plate combining a cholesteric liquid crystal layer and a ⁇ / 4 plate reflects right circularly polarized light (or left circularly polarized light) out of incident light and transmits left circularly polarized light (or right circularly polarized light).
  • the linearly polarized light emitted from the liquid crystal display is converted into left-handed circularly polarized light (or right-handed circularly polarized light) by a ⁇ / 4 plate so that the display light is transmitted to the viewer side, and outside the right-handed circularly polarized light (or left-handed circularly polarized light). The light can be reflected to the viewer side.
  • Patent Document 8 discloses a method of stacking a plurality of cholesteric liquid crystal layers having different reflection bands and changing the helical pitch stepwise (Patent Document 8) And a method of continuously changing the spiral pitch of the cholesteric liquid crystal layer in the layer direction (see Patent Documents 9 to 12).
  • Patent Documents 10 and 11 disclose a method for obtaining a reflection band in a very wide range of 420 to 900 nm that substantially includes the visible light region (380 to 780 nm).
  • the present invention has been made in view of the above-described present situation, and makes use of the advantage of using a cholesteric liquid crystal layer as a half mirror layer, and a mirror display in which the color shift of the reflected color of the mirror display at the front viewing angle and the oblique viewing angle is suppressed. Is intended to provide.
  • the present inventors have shifted the reflection spectrum of the cholesteric liquid crystal layer to the short wavelength side at an oblique viewing angle, so that the cholesteric having a reflection band in the visible light region at the front viewing angle.
  • a cholesteric liquid crystal layer having a reflection band in the infrared light region at the front viewing angle is provided, and the present invention has been achieved.
  • one embodiment of the present invention includes a half mirror plate and a display panel disposed on the back side of the half mirror plate, and the half mirror plate includes a first visible light reflecting cholesteric liquid crystal layer and a red panel.
  • a mirror display having an external light reflecting cholesteric liquid crystal layer.
  • the mirror display of the present invention it is possible to suppress the color shift of the reflected color of the mirror display at the front viewing angle and the oblique viewing angle while taking advantage of the cholesteric liquid crystal layer as the half mirror layer.
  • FIG. 1 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Example 1.
  • FIG. 6 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Example 2.
  • FIG. 6 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Example 3.
  • FIG. 6 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Example 4.
  • FIG. 10 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Example 5.
  • FIG. 10 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Example 6.
  • FIG. 6 is a schematic cross-sectional view showing a configuration of a mirror display according to Comparative Example 1.
  • FIG. 10 is a schematic cross-sectional view showing a configuration of a mirror display according to Comparative Example 2.
  • FIG. It is a cross-sectional schematic diagram which shows the structure of the mirror display which concerns on the comparative example 3.
  • FIG. It is a cross-sectional schematic diagram which shows the structure of the mirror display which concerns on the comparative example 4.
  • 10 is a schematic cross-sectional view showing a configuration of a mirror display according to Comparative Example 5.
  • FIG. 10 is a schematic cross-sectional view showing a configuration of a mirror display according to Comparative Example 6.
  • FIG. 1 is a schematic cross-sectional view illustrating a configuration of a mirror display according to an embodiment.
  • the mirror display of this embodiment includes a half mirror plate 10, a liquid crystal panel (display panel) 20 a, and a backlight 30.
  • An observer of the mirror display visually recognizes the surface of the half mirror plate 10.
  • the upper direction in FIG. 1 is called the observer side
  • the lower direction in FIG. 1 is called the back side (the same applies to FIGS. 3 to 14).
  • the half mirror plate 10 includes a transparent substrate 11 and a cholesteric liquid crystal layer.
  • the transparent substrate 11 is preferably arranged closer to the viewer than the cholesteric liquid crystal layer. By providing the transparent substrate 11, scratch resistance and ease of maintenance can be improved.
  • the transparent substrate 11 is not particularly limited, and a resin substrate such as an acrylic plate or a glass substrate can be used. From the viewpoint of sufficiently functioning the half mirror plate 10 as a mirror, it is preferable not to arrange an antireflection film on the observer side of the half mirror plate 10. On the other hand, from the viewpoint of effectively using the display light emitted from the liquid crystal panel 20a, an antireflection film may be disposed on the liquid crystal panel 20a side of the half mirror plate 10.
  • the cholesteric liquid crystal layer includes a first visible light reflection cholesteric liquid crystal layer 13 and an infrared light reflection cholesteric liquid crystal layer 15.
  • the “visible light reflecting cholesteric liquid crystal layer” means a cholesteric liquid crystal layer having a reflection band at a front viewing angle in the visible light region (wavelength 380 to 780 nm).
  • the “infrared light reflecting cholesteric liquid crystal layer” means a cholesteric liquid crystal layer having a reflection band at the front viewing angle in the infrared light region, and at least a wavelength of 780 to 1400 nm corresponding to near infrared light. It is preferable to have a reflection band in the region.
  • the “reflection band at the front viewing angle” means a wavelength region in which a reflectance of half or more of the maximum reflectance is obtained under conditions of an incident angle of 5 degrees and an observation angle of 5 degrees.
  • the first visible light reflecting cholesteric liquid crystal layer 13 and the infrared light reflecting cholesteric liquid crystal layer 15 have the same rotation direction of circularly polarized light that is transmitted to each other.
  • the infrared light reflecting cholesteric liquid crystal layer 15 also reflects right circularly polarized light, It is preferable to transmit left circularly polarized light.
  • the first visible light reflecting cholesteric liquid crystal layer 13 and the infrared light reflecting cholesteric liquid crystal layer 15 may have a film form made of a cholesteric liquid crystal film attached to the transparent substrate 11, or on the transparent substrate 11. You may have the resin layer form which consists of the formed cholesteric liquid crystal resin layer.
  • An adhesive can be used for attaching the cholesteric liquid crystal film to the transparent substrate 11. That is, the first visible light reflecting cholesteric liquid crystal layer 13 or infrared light reflecting cholesteric liquid crystal layer 15 and the transparent substrate 11 may be in direct contact with each other, or the first visible light reflecting cholesteric liquid crystal layer 13 or infrared light.
  • a pressure-sensitive adhesive layer may be interposed between the reflective cholesteric liquid crystal layer 15 and the transparent substrate 11.
  • a pressure-sensitive adhesive layer adhesive layer
  • the resin layer form is preferable.
  • the first visible light reflecting cholesteric liquid crystal layer 13 is located on the transparent substrate 11 side, but the infrared light reflecting cholesteric liquid crystal layer 15 may be located on the transparent substrate 11 side. . Further, the first visible light reflecting cholesteric liquid crystal layer 13 and the infrared light reflecting cholesteric liquid crystal layer 15 may be in direct contact with each other, or the first visible light reflecting cholesteric liquid crystal layer 13 and the infrared light reflecting cholesteric liquid crystal layer 15. Between 15, other members such as a pressure-sensitive adhesive layer (adhesive layer) may be interposed.
  • a pressure-sensitive adhesive layer adheresive layer
  • the liquid crystal panel 20a includes, in order from the observer side, a first ⁇ / 4 plate 21, a first absorption linear polarizing plate (first linear polarizing plate) 22, a color filter substrate 23, a liquid crystal layer 24, and a TFT substrate 25.
  • the second absorption linearly polarizing plate (second linearly polarizing plate) 26 is disposed.
  • An antireflection film may be disposed on the surface of the first ⁇ / 4 plate 21 facing the half mirror plate 10, or on the surface of the half mirror plate 10 facing the first ⁇ / 4 plate 21.
  • An antireflection film may be disposed.
  • Both the first absorption linear polarizing plate 22 and the second absorption linear polarizing plate 26 may be replaced with a reflection polarizing plate.
  • the display light of the liquid crystal panel 20 a becomes circularly polarized light by passing through the first absorption type linearly polarizing plate 22 and the first ⁇ / 4 plate 21. In other words, in the display mode for displaying an image, the liquid crystal panel 20 a emits circularly polarized light toward the half mirror plate 10.
  • ⁇ / 4 plate means a birefringent body that gives a phase difference of a quarter of the wavelength ⁇ of visible light, but at least transmits light having a wavelength of 550 nm.
  • the optical member is not particularly limited as long as the optical member gives a phase difference of 120 to 160 nm.
  • the first ⁇ / 4 plate 21 may be bonded to the surface on the viewer side of the first absorption linear polarizing plate 22 using an adhesive, or the polarization in the first absorption linear polarizing plate 22. It may also serve as a child protective layer (PVA protective layer) and may be incorporated in the first absorption linear polarizing plate 22.
  • PVA protective layer child protective layer
  • a reflective polarizing plate (half mirror layer) is configured by combining the cholesteric liquid crystal layer in the half mirror plate 10 and the first ⁇ / 4 plate 21 in the liquid crystal panel 20a.
  • the reflective polarizing plate combining the cholesteric liquid crystal layer and the ⁇ / 4 plate converts the linearly polarized light transmitted through the first absorption linear polarizing plate 22 into the first ⁇ /
  • the four plates 21 convert the display light of the liquid crystal panel 20a to the viewer side by converting into left circularly polarized light (or right circularly polarized light) that can be transmitted through the cholesteric liquid crystal layer.
  • the reflective polarizing plate that combines the cholesteric liquid crystal layer and the ⁇ / 4 plate reflects the external light of right circularly polarized light (or left circularly polarized light) to the viewer side.
  • the linearly polarized light does not enter from the first absorption type linear polarizing plate 22 side, the display light of the liquid crystal panel 20a is not emitted to the viewer side.
  • the display mode and the mirror mode are switched according to the display state of the liquid crystal panel 20a.
  • the first absorption linear polarizing plate 22 is attached to the color filter substrate 23 via an adhesive
  • the second absorption linear polarizing plate 26 is attached to the TFT substrate 25 via an adhesive.
  • a reflective polarizing plate may be laminated on the backlight 30 side of the second absorption linear polarizing plate 26. Further, the second absorption linear polarizing plate 26 may be replaced with a reflective polarizing plate.
  • the reflective polarizing plate use may be made of a multilayer reflective polarizing plate (trade name: DBEF) manufactured by 3M Japan, or a reflective polarizing plate in which a ⁇ / 4 plate is attached to the observer side of the cholesteric liquid crystal film. it can. If the second absorption type linear polarizing plate 26 is replaced with a reflection type linear polarizing plate, the backlight light absorbed by the second absorption type linear polarizing plate 26 is reused. Can be raised.
  • the backlight 30 may be a direct type or an edge light type.
  • the light source used for the backlight 30 may be a light emitting diode (LED) 31 or a fluorescent tube.
  • the liquid crystal panel 20a is used as the display panel.
  • the type of the display panel applicable to the present invention is not particularly limited.
  • an organic electroluminescence display (OELD) is an organic electroluminescence display (OELD). It may be a plasma display.
  • OELD organic electroluminescence display
  • a so-called 3D display capable of observing a stereoscopic (3D) image may be used.
  • 3D-compatible display a natural depth feeling can be provided for the display as well as the mirror display, the design of the mirror display can be improved, and the mirror display can be used in various applications.
  • the stereoscopic image display method of the 3D-compatible display is not particularly limited, and any method can be used, but a naked-eye method that does not require glasses is more preferable. Examples of the naked-eye 3D display include a lenticular lens method and a parallax barrier method.
  • the mirror display of this embodiment has the following advantages.
  • (1) The cholesteric liquid crystal layer has a characteristic that the reflection band is shifted to the short wavelength side (blue shift) at an oblique viewing angle based on the Bragg reflection condition shown in the following formula.
  • ⁇ 0 nPcos ⁇ sin ⁇ 1 (sin ⁇ / n) ⁇
  • ⁇ 0 is the center wavelength of the reflection wavelength region
  • n is the average refractive index
  • P is the length of the helical pitch
  • ⁇ is the incident angle of the incident light to the cholesteric liquid crystal layer.
  • the cholesteric liquid crystal layer exhibits a phenomenon (blue shift) in which the reflection spectrum shifts to the short wavelength side at an oblique viewing angle.
  • FIG. 2 is a graph comparing the reflection spectra of the front viewing angle and the oblique viewing angle in the cholesteric liquid crystal layer.
  • the wavelength shift amount in the blue shift is larger on the long wavelength side, and a wavelength shift exceeding 200 nm occurs when the incident angle is large on the long wavelength side. For this reason, even in the cholesteric liquid crystal layer having a wide reflection band, a sufficient reflectance in the red region of visible light cannot be obtained, and the color of the reflected light deviates between the front viewing angle and the oblique viewing angle.
  • the direction of the slow axis of the first ⁇ / 4 plate 21 of the liquid crystal panel 20a with respect to the cholesteric liquid crystal layer of the half mirror plate 10 can be arbitrarily set. For this reason, it is not necessary to set a highly accurate axis between the half mirror plate 10 and the liquid crystal panel 20a, and the brightness of the display display light does not change even when a positional deviation occurs.
  • the multilayer reflective polarizing plate since the multilayer reflective polarizing plate has a size limit, there is a restriction in the transmission axis direction even in the case of a half mirror plate.
  • the transmission axis of the observer-side absorption polarizing plate of the liquid crystal panel is inclined with respect to each side of the half mirror plate, the area ratio of the product that can be cut out from the original fabric roll (efficiency of the original fabric roll) This leads to an increase in cost.
  • a multilayer reflective polarizing plate is manufactured by a roll-to-roll method in which coextrusion and transverse stretching are combined.
  • a feed block method or a multi-manifold method is used as a coextrusion method.
  • a material constituting the A layer in the multilayer reflective polarizing plate and a material constituting the B layer in the multilayer reflective polarizing plate are extruded in a feed block, Multi-layer using pliers.
  • the obtained elongate multilayer laminated body is extended
  • the material constituting the A layer for example, polyethylene naphthalate
  • the material constituting the B layer for example, copolyester of naphthalenedicarboxylic acid and terephthalic acid
  • the material constituting the B layer does not increase the refractive index in any direction.
  • the transmission axis of the multilayer reflective polarizing plate is parallel to the transport direction, that is, the long direction of the multilayer laminate
  • the transmission axis of the observer-side absorption polarizing plate of the liquid crystal panel is the short side direction.
  • the mirror display in which the long side size of the half mirror plate is equal to or smaller than the width size (TD length) of the multilayer laminate can be manufactured.
  • the multilayer reflection type polarizing plate has a problem that the appearance of the display light becomes dark when the polarized light is put on since the emitted light is linearly polarized light.
  • Patent Document 7 discloses an observer of a multilayer reflective polarizing plate so that the angle formed by the transmission axis of the multilayer reflective polarizing plate and the slow axis of the ⁇ / 4 plate is 45 °. A method of attaching a ⁇ / 4 plate to the side surface has been proposed.
  • Recent small- and medium-sized liquid crystal displays for smartphones, tablets, and in-vehicle applications may be designed so that the emitted light is circularly polarized so that the display can be seen even when wearing polarized sunglasses.
  • the absorption polarizing plate used in a liquid crystal display is a linear polarizing plate made of a polyvinyl alcohol (PVA) dyed stretched film polarizer and a triacetyl cellulose (TAC) protective layer, and the light emitted from the display is Linearly polarized light.
  • PVA polyvinyl alcohol
  • TAC triacetyl cellulose
  • the ⁇ / 4 plate is attached to the linearly polarizing plate so that the angle formed by the absorption axis of the linearly polarizing plate and the slow axis of the ⁇ / 4 plate is 45 °.
  • the above method includes a process of cutting or punching the linearly polarizing plate and the ⁇ / 4 plate into a predetermined shape and a process of bonding the ⁇ / 4 plate to the linearly polarizing plate, so that the number of processes is large.
  • Visible light reflective cholesteric liquid crystal films used in Examples and Comparative Examples were produced by carrying out the following steps (A1) to (A6).
  • A1 94.8 parts by weight of a polymerizable liquid crystal compound of the following chemical formula (1), 5.2 parts by weight of a chiral agent (“LC756” manufactured by BASF), and a photopolymerization initiator (“IRGACURE907” manufactured by BASF)
  • a polymerizable solution is obtained by dissolving 3.0 parts by weight of the mixture in cyclopentanone so as to have a solid concentration of 30% by weight.
  • the polymerizable solution is applied to a stretched PET (polyethylene terephthalate) film.
  • the applied polymerizable solution is baked at 100 ° C. for 2 minutes and dried.
  • A4 In an air atmosphere at 40 ° C., ultraviolet rays are irradiated from the stretched PET film side at an irradiation energy of 40 mW / cm 2 for 1.2 seconds.
  • A5 The temperature is raised to 90 ° C. at a rate of 3 ° C./second, and then heated for 20 seconds in an air atmosphere at 90 ° C.
  • A6 In a nitrogen atmosphere at 50 ° C., ultraviolet rays are irradiated from the stretched PET film side at an irradiation energy of 60 mW / cm 2 for 10 seconds.
  • the infrared light reflecting cholesteric liquid crystal film used in the examples was manufactured by performing the following steps (B1) to (B3).
  • (B1) 97.5 parts by weight of a polymerizable liquid crystal compound (manufactured by BASF, “LC242”), 2.5 parts by weight of a chiral agent (manufactured by BASF, “LC756”), and a thermal polymerization initiator (Wako Pure Chemical Industries, Ltd.)
  • a polymerizable solution is obtained by dissolving 1.0 part by weight of a mixture (manufactured by “V-65”) in cyclopentanone so as to have a solid concentration of 30% by weight.
  • (B2) The polymerizable solution is applied to the stretched PET film.
  • (B3) Heat at 100 ° C. for 10 minutes in a nitrogen gas atmosphere containing 0.5% by volume of oxygen.
  • the pressure-sensitive adhesive used in Examples and Comparative Examples was “PD-S1” manufactured by Panac Corporation.
  • a 5-inch full high-definition (FHD) liquid crystal module (manufactured by Sharp) is disassembled into a liquid crystal panel 20a and a backlight 30, and the liquid crystal panel 20a is placed on the first absorption type linear polarizing plate 22 located on the viewer side.
  • First ⁇ / 4 plate 21 (manufactured by Nippon Zeon Co., Ltd., “ZD film”) was attached. At this time, the angle between the transmission axis of the first absorption type linear polarizing plate 22 and the slow axis of the first ⁇ / 4 plate 21 was adjusted to 45 °.
  • Example 2 A mirror display having the configuration shown in FIG. 4 was produced.
  • FIG. 4 is a schematic cross-sectional view illustrating the configuration of the mirror display according to the second embodiment.
  • the visible light reflecting cholesteric liquid crystal resin layer 13 b was formed directly on the glass substrate 11.
  • an infrared light reflecting cholesteric liquid crystal film 15a with a stretched PET film was attached onto the visible light reflecting cholesteric liquid crystal resin layer 13b using an adhesive.
  • the half mirror plate 10b of Example 2 was completed by peeling a stretched PET film from the infrared light reflection cholesteric liquid crystal film 15a.
  • a mirror display of Example 2 was produced in the same manner as Example 1 except for the manufacturing process of the half mirror plate 10b described above.
  • FIG. 5 is a schematic cross-sectional view illustrating the configuration of the mirror display according to the third embodiment.
  • a reflective linear polarizing plate 27 manufactured by 3M Japan, “DBEF”
  • DBEF 3M Japan
  • FIG. 6 is a schematic cross-sectional view illustrating the configuration of the mirror display according to the fourth embodiment.
  • the second ⁇ / 4 plate 28 manufactured by Zeon Corporation, “ZD film”
  • stretched PET are used on the backlight 30 side of the second absorption linear polarizing plate 26 using an adhesive.
  • a second visible light reflecting cholesteric liquid crystal film 29 with a film was attached in order, and the stretched PET film was peeled from the second visible light reflecting cholesteric liquid crystal film 29.
  • the mirror display of Example 4 was produced through the same steps as in Example 1.
  • FIG. 8 is a schematic cross-sectional view illustrating the configuration of the mirror display according to the sixth embodiment.
  • a second ⁇ / 4 plate 28 manufactured by Nippon Zeon Co., Ltd., “ZD film”
  • ZD film a second visible light reflection with a stretched PET film
  • Example 6 A cholesteric liquid crystal film 29 was attached in order, and the stretched PET film was peeled off from the second visible light reflecting cholesteric liquid crystal film 29 to prepare a liquid crystal panel 20e. Except for the above, the mirror display of Example 6 was produced through the same steps as in Example 1.
  • FIG. 9 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Comparative Example 1.
  • a half-mirror plate 60a of Comparative Example 1 was prepared by attaching a reflective linearly polarizing plate 62 (manufactured by 3M Japan, “DBEF”) to the glass substrate 61 using an adhesive. Further, the 5-inch full high vision (FHD) liquid crystal module (manufactured by Sharp) used in Example 1 was used as it was without being disassembled.
  • DBEF reflective linearly polarizing plate
  • FHD full high vision
  • the first ⁇ / 4 plate 21 is provided in the liquid crystal panel 20a of the first embodiment, but nothing is pasted on the first absorption type linear polarizing plate 22 in the liquid crystal panel 70a of the first comparative example. It was not attached. Except for the above, the mirror display of Comparative Example 1 was produced through the same steps as in Example 1.
  • FIG. 10 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Comparative Example 2.
  • a visible light reflective cholesteric liquid crystal film 63a with a stretched PET film was attached to the glass substrate 61 using an adhesive. Thereafter, the stretched PET film was peeled from the visible light reflecting cholesteric liquid crystal film 63a.
  • the half mirror plate 60b of the comparative example 2 was produced by affixing (lambda) / 4 board 64 (made by Nippon Zeon Co., Ltd., "ZD film”) to the visible light reflection cholesteric liquid crystal film 63a using an adhesive. Except for the above, the mirror display of Comparative Example 2 was produced through the same steps as in Comparative Example 1.
  • FIG. 11 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Comparative Example 3.
  • a ⁇ / 4 plate 64 manufactured by Nippon Zeon Co., Ltd., “ZD film”
  • DBEF reflective linear polarizing plate 62
  • FIG. 12 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Comparative Example 4.
  • a visible light reflective cholesteric liquid crystal film 63a with a stretched PET film was attached to the glass substrate 61 using an adhesive.
  • the stretched PET film was peeled off from the visible reflective cholesteric liquid crystal film 63a to complete the half mirror plate 60d of Comparative Example 4.
  • a mirror display of Comparative Example 4 was produced in the same manner as in Example 1 except for the manufacturing process of the half mirror plate described above.
  • FIG. 14 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Comparative Example 6.
  • the mirror display according to Comparative Example 6 includes a ⁇ / 4 plate-integrated circularly polarizing plate 73 as a countermeasure against polarized sunglasses.
  • the first ⁇ / 4 plate 21 and the first absorption linear polarizing plate 22 are provided independently, but in the liquid crystal panel 70b of Comparative Example 6, A ⁇ / 4 plate-integrated circularly polarizing plate 73, which is a laminate including the ⁇ / 4 plate 71 and the absorption linearly polarizing plate 72, was provided on the viewer side.
  • the mirror display of Comparative Example 6 was produced through the same steps as in Comparative Example 4.
  • the results of the evaluation test 1 are shown in Table 1. As shown in Table 1, the brightness of the mirror displays of Comparative Examples 1 to 3 was greatly changed by rotating the half mirror plate. On the other hand, in the mirror displays of Examples 1 to 6 and Comparative Examples 4 to 6, the luminance hardly changed even when the half mirror plate was rotated. From the results of Evaluation Test 1, it was found that the brightness of the mirror displays of Comparative Examples 1 to 3 was likely to change due to the misalignment between the half mirror plate and the liquid crystal panel.
  • One embodiment of the present invention includes a half mirror plate and a display panel disposed on the back side of the half mirror plate, the half mirror plate including a first visible light reflecting cholesteric liquid crystal layer and infrared light.
  • a mirror display having a reflective cholesteric liquid crystal layer.
  • the half mirror plate further includes a first pressure-sensitive adhesive layer that joins the first visible light reflection cholesteric liquid crystal layer and the infrared light reflection cholesteric liquid crystal layer.
  • the half mirror plate further includes a transparent substrate.
  • the half mirror plate further includes a second pressure-sensitive adhesive layer that joins the first visible light reflection cholesteric liquid crystal layer or the infrared light reflection cholesteric liquid crystal layer and the transparent substrate.
  • the first visible light reflecting cholesteric liquid crystal layer or the infrared light reflecting cholesteric liquid crystal layer is in direct contact with the transparent substrate.
  • the display panel includes a liquid crystal layer disposed on the back side of the first linear polarizing plate.
  • the display panel may further include (1) a reflective polarizing plate disposed on the back side of the liquid crystal layer, and (2) a second ⁇ disposed on the back side of the liquid crystal layer. / 4 plate and a second visible light reflecting cholesteric liquid crystal layer disposed on the back side of the second ⁇ / 4 plate, and (3) disposed on the back side of the liquid crystal layer. It may have a second linearly polarizing plate.
  • the display panel further includes (3-1) a second ⁇ / 4 plate disposed on the back side of the second linearly polarizing plate, and the second ⁇ / 4 plate. And a second visible light reflecting cholesteric liquid crystal layer disposed on the back side of the light source, and (3-2) a reflective polarizing plate disposed on the back side of the second linear polarizing plate. You may have.
  • it further includes a backlight disposed on the back side of the display panel.

Abstract

The present invention provides a mirror display wherein color shift in reflected colors of the mirror display at a frontal viewing angle and an oblique viewing angle is suppressed while taking advantage of using cholesteric liquid crystal layers in a half mirror layer. This mirror display is provided with a half mirror plate and a display panel disposed on the back surface side of the half mirror plate. The half mirror plate has a first visible light reflecting cholesteric liquid crystal layer and an infrared light reflecting cholesteric liquid crystal layer.

Description

ミラーディスプレイMirror display
本発明は、ミラーディスプレイに関する。より詳しくは、ミラーとして機能するミラーモード及び画像を表示するディスプレイモードを両立したミラーディスプレイに関するものである。 The present invention relates to a mirror display. More specifically, the present invention relates to a mirror display that achieves both a mirror mode that functions as a mirror and a display mode that displays an image.
近年、液晶ディスプレイの観察者（ユーザー）側にハーフミラー層を設けることで、液晶ディスプレイの非表示時にミラーとして利用できるミラーディスプレイが提案されている（特許文献１～７参照）。ミラーディスプレイでは、液晶ディスプレイから表示光が出射している状態において、表示光による表示が行われ、一方、液晶ディスプレイから表示光が出射していない状態において、外光を反射することによりミラーとして使用される。現在、ミラーディスプレイは、車載ルームミラーやデジタルサイネージ等への応用が検討されている。 In recent years, there has been proposed a mirror display that can be used as a mirror when the liquid crystal display is not displayed by providing a half mirror layer on the viewer (user) side of the liquid crystal display (see Patent Documents 1 to 7). In the mirror display, the display light is displayed when the display light is emitted from the liquid crystal display, while the display is used as a mirror by reflecting external light when the display light is not emitted from the liquid crystal display. Is done. Currently, application of mirror displays to in-vehicle room mirrors, digital signage, and the like is being studied.
ハーフミラー層としては、多層反射型偏光板や、コレステリック液晶フィルム及びλ／４板を組み合わせた反射型偏光板が用いられてきた。多層反射型偏光板は、入射光のうちの反射軸と平行な方向の偏光を反射し、反射軸と直交する方向の偏光を透過させる機能を有している。そのため、多層反射型偏光板は、液晶ディスプレイから出射された光を表示光として観察者側へ透過させ、その表示光の偏光方向と直交する方向の外光を観察者側へ反射することができる。 As the half mirror layer, a multilayer reflective polarizing plate or a reflective polarizing plate in which a cholesteric liquid crystal film and a λ / 4 plate are combined has been used. The multilayer reflective polarizing plate has a function of reflecting polarized light in a direction parallel to the reflection axis of incident light and transmitting polarized light in a direction orthogonal to the reflection axis. Therefore, the multilayer reflective polarizing plate can transmit light emitted from the liquid crystal display to the viewer as display light, and can reflect external light in a direction orthogonal to the polarization direction of the display light to the viewer. .
一方、コレステリック液晶層及びλ／４板を組み合わせた反射型偏光板は、入射光のうち、右円偏光（又は左円偏光）を反射し、左円偏光（又は右円偏光）を透過させる。液晶ディスプレイから出射された直線偏光をλ／４板によって左円偏光（又は右円偏光）に変換することで表示光を観察者側に透過させ、かつ右円偏光（又は左円偏光）の外光は観察者側に反射することができる。 On the other hand, a reflective polarizing plate combining a cholesteric liquid crystal layer and a λ / 4 plate reflects right circularly polarized light (or left circularly polarized light) out of incident light and transmits left circularly polarized light (or right circularly polarized light). The linearly polarized light emitted from the liquid crystal display is converted into left-handed circularly polarized light (or right-handed circularly polarized light) by a λ / 4 plate so that the display light is transmitted to the viewer side, and outside the right-handed circularly polarized light (or left-handed circularly polarized light). The light can be reflected to the viewer side.
コレステリック液晶層及びλ／４板を組み合わせた反射型偏光板に用いられるコレステリック液晶層に関しては、反射帯域が異なる複数のコレステリック液晶層を積層して螺旋ピッチを段階的に変化させる方法（特許文献８参照）や、コレステリック液晶層の螺旋ピッチを層方向に連続的に変化させる方法（特許文献９～１２参照）が知られている。例えば、特許文献１０及び１１には、可視光領域（３８０～７８０ｎｍ）をほぼ含む、４２０～９００ｎｍと非常に広い範囲の反射帯域を得るための方法が開示されている。 Regarding a cholesteric liquid crystal layer used in a reflective polarizing plate in which a cholesteric liquid crystal layer and a λ / 4 plate are combined, a method of stacking a plurality of cholesteric liquid crystal layers having different reflection bands and changing the helical pitch stepwise (Patent Document 8) And a method of continuously changing the spiral pitch of the cholesteric liquid crystal layer in the layer direction (see Patent Documents 9 to 12). For example, Patent Documents 10 and 11 disclose a method for obtaining a reflection band in a very wide range of 420 to 900 nm that substantially includes the visible light region (380 to 780 nm).
国際公開第２０１４／１１２５２５号International Publication No. 2014/112525 国際公開第２０１５／０１９８５８号International Publication No. 2015/0198858 国際公開第２０１５／１６６８３３号International Publication No. 2015/166833 特開２００４－１２５８８５号公報JP 2004-125858 A 特開２００４－１２５８８６号公報JP 2004-125886 A 国際公開第２００５／０５０２６７号International Publication No. 2005/050267 特開２０１４－２６０５８号公報JP 2014-26058 A 特開平１０－１９７７２２号公報Japanese Patent Laid-Open No. 10-197722 特開平６－２８１８１４号公報JP-A-6-281814 特開２００４－３１８０６６号公報JP 2004-318066 A 特開２００４－３１８０６２号公報JP 2004-318062 A 特開２０１１－１３３７０７号公報JP 2011-133707 A 特開２００９－１３４２２４号公報JP 2009-134224 A 特開２００９－１２２４５４号公報JP 2009-122454 A
本発明者らの検討の結果、ハーフミラー層にコレステリック液晶層を用いれば、原理的に、多層反射型偏光板を用いる場合と比べて、ミラーディスプレイの製造上の制約が少なく、生産効率の向上に有利であることが分かった。しかしながら、ハーフミラー層にコレステリック液晶層を用いる場合には、正面視角と斜め視角でミラー表示の反射色が色ずれするという課題があった。 As a result of the study by the present inventors, if a cholesteric liquid crystal layer is used for the half mirror layer, in principle, there are fewer restrictions on the production of the mirror display compared to the case of using a multilayer reflective polarizing plate, and the production efficiency is improved. It was found to be advantageous. However, when a cholesteric liquid crystal layer is used for the half mirror layer, there is a problem that the reflected color of the mirror display is shifted in color between the front viewing angle and the oblique viewing angle.
本発明は、上記現状に鑑みてなされたものであり、ハーフミラー層にコレステリック液晶層を用いる利点を生かしつつ、正面視角と斜め視角でのミラー表示の反射色の色ずれが抑制されたミラーディスプレイを提供することを目的とするものである。 The present invention has been made in view of the above-described present situation, and makes use of the advantage of using a cholesteric liquid crystal layer as a half mirror layer, and a mirror display in which the color shift of the reflected color of the mirror display at the front viewing angle and the oblique viewing angle is suppressed. Is intended to provide.
本発明者らは、上記課題を解決すべく鋭意検討を重ねた結果、コレステリック液晶層の反射スペクトルが斜め視角において短波長側へシフトすることから、正面視角で可視光領域に反射帯域を持つコレステリック液晶層だけでなく、長波長領域の反射率を補償させるために、正面視角で赤外光領域に反射帯域を持つコレステリック液晶層を設けることを見出し、本発明に到達した。 As a result of intensive investigations to solve the above problems, the present inventors have shifted the reflection spectrum of the cholesteric liquid crystal layer to the short wavelength side at an oblique viewing angle, so that the cholesteric having a reflection band in the visible light region at the front viewing angle. In order to compensate not only the liquid crystal layer but also the reflectance in the long wavelength region, it has been found that a cholesteric liquid crystal layer having a reflection band in the infrared light region at the front viewing angle is provided, and the present invention has been achieved.
すなわち、本発明の一態様は、ハーフミラープレートと、上記ハーフミラープレートの背面側に配置された表示パネルとを備え、上記ハーフミラープレートは、第１の可視光反射コレステリック液晶層、及び、赤外光反射コレステリック液晶層を有するミラーディスプレイである。 That is, one embodiment of the present invention includes a half mirror plate and a display panel disposed on the back side of the half mirror plate, and the half mirror plate includes a first visible light reflecting cholesteric liquid crystal layer and a red panel. A mirror display having an external light reflecting cholesteric liquid crystal layer.
本発明のミラーディスプレイによれば、ハーフミラー層にコレステリック液晶層を用いる利点を生かしつつ、正面視角と斜め視角でのミラー表示の反射色の色ずれを抑制できる。 According to the mirror display of the present invention, it is possible to suppress the color shift of the reflected color of the mirror display at the front viewing angle and the oblique viewing angle while taking advantage of the cholesteric liquid crystal layer as the half mirror layer.
実施形態に係るミラーディスプレイの構成を示す断面模式図である。It is a cross-sectional schematic diagram which shows the structure of the mirror display which concerns on embodiment. コレステリック液晶層における正面視角と斜め視角の反射スペクトルを対比したグラフである。It is the graph which contrasted the reflection spectrum of the front viewing angle and the diagonal viewing angle in a cholesteric liquid crystal layer. 実施例１に係るミラーディスプレイの構成を示す断面模式図である。1 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Example 1. FIG. 実施例２に係るミラーディスプレイの構成を示す断面模式図である。6 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Example 2. FIG. 実施例３に係るミラーディスプレイの構成を示す断面模式図である。6 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Example 3. FIG. 実施例４に係るミラーディスプレイの構成を示す断面模式図である。6 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Example 4. FIG. 実施例５に係るミラーディスプレイの構成を示す断面模式図である。10 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Example 5. FIG. 実施例６に係るミラーディスプレイの構成を示す断面模式図である。10 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Example 6. FIG. 比較例１に係るミラーディスプレイの構成を示す断面模式図である。6 is a schematic cross-sectional view showing a configuration of a mirror display according to Comparative Example 1. FIG. 比較例２に係るミラーディスプレイの構成を示す断面模式図である。10 is a schematic cross-sectional view showing a configuration of a mirror display according to Comparative Example 2. FIG. 比較例３に係るミラーディスプレイの構成を示す断面模式図である。It is a cross-sectional schematic diagram which shows the structure of the mirror display which concerns on the comparative example 3. FIG. 比較例４に係るミラーディスプレイの構成を示す断面模式図である。It is a cross-sectional schematic diagram which shows the structure of the mirror display which concerns on the comparative example 4. 比較例５に係るミラーディスプレイの構成を示す断面模式図である。10 is a schematic cross-sectional view showing a configuration of a mirror display according to Comparative Example 5. FIG. 比較例６に係るミラーディスプレイの構成を示す断面模式図である。10 is a schematic cross-sectional view showing a configuration of a mirror display according to Comparative Example 6. FIG.
以下に、本発明に係るミラーディスプレイの一実施形態を示す。なお、本発明は、以下の実施形態に限定されるものではない。 Below, one Embodiment of the mirror display which concerns on this invention is shown. In addition, this invention is not limited to the following embodiment.
図１は、実施形態に係るミラーディスプレイの構成を示す断面模式図である。本実施形態のミラーディスプレイは、ハーフミラープレート１０と、液晶パネル（表示パネル）２０ａと、バックライト３０とを備える。ミラーディスプレイの観察者は、ハーフミラープレート１０の表面を視認する。以下では、図１の上方向を観察者側と呼び、図１の下方向を背面側と呼ぶ（図３～１４についても同様）。 FIG. 1 is a schematic cross-sectional view illustrating a configuration of a mirror display according to an embodiment. The mirror display of this embodiment includes a half mirror plate 10, a liquid crystal panel (display panel) 20 a, and a backlight 30. An observer of the mirror display visually recognizes the surface of the half mirror plate 10. In the following, the upper direction in FIG. 1 is called the observer side, and the lower direction in FIG. 1 is called the back side (the same applies to FIGS. 3 to 14).
ミラーディスプレイは、ディスプレイモードにおいて、液晶パネル２０ａで生成した画像を表示し、ミラーモードにおいて、観察者側から入射した光を反射するミラーとして機能する。ディスプレイモードとミラーモードは、時間的に切り換えられてもよいし、表示面内で空間的に区分されるものであってもよい。 The mirror display functions as a mirror that displays an image generated by the liquid crystal panel 20a in the display mode and reflects light incident from the viewer side in the mirror mode. The display mode and the mirror mode may be switched temporally or may be spatially divided in the display surface.
ハーフミラープレート１０は、液晶パネル２０ａの表示光を透過させ、かつミラーディスプレイにミラーとしての機能を付与する部材である。なお、ハーフミラープレート１０と液晶パネル２０ａとは、それらの間に空気層が設けられた状態で、金属フレーム等によって固定されてもよいし、それらの間に空気層が設けられないように、光学透明粘着剤（ＯＣＡ：Ｏｐｔｉｃａｌ　Ｃｌｅａｒ　Ａｄｈｅｓｉｖｅ）等で接着されてもよい。 The half mirror plate 10 is a member that transmits the display light of the liquid crystal panel 20a and gives the mirror display a function as a mirror. In addition, the half mirror plate 10 and the liquid crystal panel 20a may be fixed by a metal frame or the like with an air layer provided therebetween, or an air layer may not be provided between them. You may adhere | attach with an optical transparent adhesive (OCA: Optical Clear Adhesive) etc.
ハーフミラープレート１０は、透明基板１１と、コレステリック液晶層とで構成される。透明基板１１は、コレステリック液晶層よりも観察者側に配置されることが好ましい。透明基板１１を設けることによって、耐擦傷性やメンテナンスのし易さを向上させることができる。透明基板１１としては特に限定されず、アクリル板等の樹脂基板や、ガラス基板を用いることができる。ハーフミラープレート１０をミラーとして充分に機能させる観点から、ハーフミラープレート１０の観察者側には反射防止膜を配置しないことが好ましい。一方、液晶パネル２０ａから出射される表示光を有効活用する観点から、ハーフミラープレート１０の液晶パネル２０ａ側には反射防止膜を配置してもよい。 The half mirror plate 10 includes a transparent substrate 11 and a cholesteric liquid crystal layer. The transparent substrate 11 is preferably arranged closer to the viewer than the cholesteric liquid crystal layer. By providing the transparent substrate 11, scratch resistance and ease of maintenance can be improved. The transparent substrate 11 is not particularly limited, and a resin substrate such as an acrylic plate or a glass substrate can be used. From the viewpoint of sufficiently functioning the half mirror plate 10 as a mirror, it is preferable not to arrange an antireflection film on the observer side of the half mirror plate 10. On the other hand, from the viewpoint of effectively using the display light emitted from the liquid crystal panel 20a, an antireflection film may be disposed on the liquid crystal panel 20a side of the half mirror plate 10.
コレステリック液晶層は、第１の可視光反射コレステリック液晶層１３、及び、赤外光反射コレステリック液晶層１５を含む。本明細書において、「可視光反射コレステリック液晶層」とは、可視光領域（波長３８０～７８０ｎｍ）に、正面視角での反射帯域を持つコレステリック液晶層を意味する。また、「赤外光反射コレステリック液晶層」とは、赤外光領域に、正面視角での反射帯域を持つコレステリック液晶層を意味し、少なくとも、近赤外光に相当する波長７８０～１４００ｎｍの波長領域内に反射帯域を有することが好ましい。「正面視角での反射帯域」とは、入射角５度及び観測角５度の条件で、最大反射率の半分以上の反射率が得られる波長領域を意味する。 The cholesteric liquid crystal layer includes a first visible light reflection cholesteric liquid crystal layer 13 and an infrared light reflection cholesteric liquid crystal layer 15. In the present specification, the “visible light reflecting cholesteric liquid crystal layer” means a cholesteric liquid crystal layer having a reflection band at a front viewing angle in the visible light region (wavelength 380 to 780 nm). The “infrared light reflecting cholesteric liquid crystal layer” means a cholesteric liquid crystal layer having a reflection band at the front viewing angle in the infrared light region, and at least a wavelength of 780 to 1400 nm corresponding to near infrared light. It is preferable to have a reflection band in the region. The “reflection band at the front viewing angle” means a wavelength region in which a reflectance of half or more of the maximum reflectance is obtained under conditions of an incident angle of 5 degrees and an observation angle of 5 degrees.
第１の可視光反射コレステリック液晶層１３と赤外光反射コレステリック液晶層１５は、互いに透過する円偏光の回転方向が同じであることが好ましい。第１の可視光反射コレステリック液晶層１３が、右円偏光を反射し、左円偏光を透過させるものである場合には、赤外光反射コレステリック液晶層１５もまた、右円偏光を反射し、左円偏光を透過させるものであることが好ましい。 It is preferable that the first visible light reflecting cholesteric liquid crystal layer 13 and the infrared light reflecting cholesteric liquid crystal layer 15 have the same rotation direction of circularly polarized light that is transmitted to each other. When the first visible light reflecting cholesteric liquid crystal layer 13 reflects right circularly polarized light and transmits left circularly polarized light, the infrared light reflecting cholesteric liquid crystal layer 15 also reflects right circularly polarized light, It is preferable to transmit left circularly polarized light.
第１の可視光反射コレステリック液晶層１３、及び、赤外光反射コレステリック液晶層１５は、透明基板１１に貼り付けたコレステリック液晶フィルムからなるフィルム形態を有してもよいし、透明基板１１上に形成されたコレステリック液晶樹脂層からなる樹脂層形態を有してもよい。コレステリック液晶フィルムの透明基板１１への貼り付けには、粘着剤（接着剤）を用いることができる。すなわち、第１の可視光反射コレステリック液晶層１３又は赤外光反射コレステリック液晶層１５と透明基板１１とは、直に接してもよいし、第１の可視光反射コレステリック液晶層１３又は赤外光反射コレステリック液晶層１５と透明基板１１との間に、粘着剤層（接着剤層）等の他の部材が介在してもよい。透明基板１１上にコレステリック液晶を直接塗工してコレステリック液晶樹脂層を形成する場合には、コレステリック液晶樹脂層の表面平滑性を確保しやすく、ミラー表示のぼけ（鮮明さが失われること）を効果的に防止できる。このため、ミラー表示のぼけを防止する観点からは、樹脂層形態が好ましい。 The first visible light reflecting cholesteric liquid crystal layer 13 and the infrared light reflecting cholesteric liquid crystal layer 15 may have a film form made of a cholesteric liquid crystal film attached to the transparent substrate 11, or on the transparent substrate 11. You may have the resin layer form which consists of the formed cholesteric liquid crystal resin layer. An adhesive (adhesive) can be used for attaching the cholesteric liquid crystal film to the transparent substrate 11. That is, the first visible light reflecting cholesteric liquid crystal layer 13 or infrared light reflecting cholesteric liquid crystal layer 15 and the transparent substrate 11 may be in direct contact with each other, or the first visible light reflecting cholesteric liquid crystal layer 13 or infrared light. Other members such as a pressure-sensitive adhesive layer (adhesive layer) may be interposed between the reflective cholesteric liquid crystal layer 15 and the transparent substrate 11. When the cholesteric liquid crystal resin layer is formed by directly coating the cholesteric liquid crystal on the transparent substrate 11, it is easy to ensure the surface smoothness of the cholesteric liquid crystal resin layer, and blurring of the mirror display (clearness is lost). It can be effectively prevented. For this reason, from the viewpoint of preventing blurring of mirror display, the resin layer form is preferable.
第１の可視光反射コレステリック液晶層１３及び赤外光反射コレステリック液晶層１５としては特に限定されず、例えば、特許文献８～１２に記載されたものを用いることができるが、コレステリック液晶層の積層層を減らし、薄くする観点からは、コレステリック液晶層の螺旋ピッチを層方向に連続的に変化させた単層タイプが好適に用いられる。 The first visible light reflecting cholesteric liquid crystal layer 13 and the infrared light reflecting cholesteric liquid crystal layer 15 are not particularly limited, and for example, those described in Patent Documents 8 to 12 can be used. From the viewpoint of reducing the layer thickness and reducing the thickness, a single layer type in which the helical pitch of the cholesteric liquid crystal layer is continuously changed in the layer direction is preferably used.
図１に示したハーフミラープレート１０では、第１の可視光反射コレステリック液晶層１３が透明基板１１側に位置するが、赤外光反射コレステリック液晶層１５が透明基板１１側に位置してもよい。また、第１の可視光反射コレステリック液晶層１３と赤外光反射コレステリック液晶層１５とは、直に接してもよいし、第１の可視光反射コレステリック液晶層１３と赤外光反射コレステリック液晶層１５の間に、粘着剤層（接着剤層）等の他の部材が介在してもよい。 In the half mirror plate 10 shown in FIG. 1, the first visible light reflecting cholesteric liquid crystal layer 13 is located on the transparent substrate 11 side, but the infrared light reflecting cholesteric liquid crystal layer 15 may be located on the transparent substrate 11 side. . Further, the first visible light reflecting cholesteric liquid crystal layer 13 and the infrared light reflecting cholesteric liquid crystal layer 15 may be in direct contact with each other, or the first visible light reflecting cholesteric liquid crystal layer 13 and the infrared light reflecting cholesteric liquid crystal layer 15. Between 15, other members such as a pressure-sensitive adhesive layer (adhesive layer) may be interposed.
液晶パネル２０ａは、観察者側から順に、第１のλ／４板２１、第１の吸収型直線偏光板（第１の直線偏光板）２２、カラーフィルタ基板２３、液晶層２４、ＴＦＴ基板２５、第２の吸収型直線偏光板（第２の直線偏光板）２６が配置された構成を有する。第１のλ／４板２１のハーフミラープレート１０と対向する面上には反射防止膜を配置してもよいし、ハーフミラープレート１０の第１のλ／４板２１と対向する面上に反射防止膜を配置してもよい。第１の吸収型直線偏光板２２、及び、第２の吸収型直線偏光板２６は、いずれも反射型偏光板に置き換えられてもよい。液晶パネル２０ａの表示光は、第１の吸収型直線偏光板２２、及び、第１のλ／４板２１を透過することで円偏光となる。すなわち、画像を表示するディスプレイモードにおいて、液晶パネル２０ａは、ハーフミラープレート１０に向けて円偏光を出射する。 The liquid crystal panel 20a includes, in order from the observer side, a first λ / 4 plate 21, a first absorption linear polarizing plate (first linear polarizing plate) 22, a color filter substrate 23, a liquid crystal layer 24, and a TFT substrate 25. The second absorption linearly polarizing plate (second linearly polarizing plate) 26 is disposed. An antireflection film may be disposed on the surface of the first λ / 4 plate 21 facing the half mirror plate 10, or on the surface of the half mirror plate 10 facing the first λ / 4 plate 21. An antireflection film may be disposed. Both the first absorption linear polarizing plate 22 and the second absorption linear polarizing plate 26 may be replaced with a reflection polarizing plate. The display light of the liquid crystal panel 20 a becomes circularly polarized light by passing through the first absorption type linearly polarizing plate 22 and the first λ / 4 plate 21. In other words, in the display mode for displaying an image, the liquid crystal panel 20 a emits circularly polarized light toward the half mirror plate 10.
本明細書において、「λ／４板」とは、可視光の波長λに対して１／４の大きさの位相差を付与する複屈折体を意味するが、少なくとも、波長５５０ｎｍの光が透過したときに、１２０～１６０ｎｍの位相差を付与する光学部材であれば特に限定されない。第１のλ／４板２１は、第１の吸収型直線偏光板２２の観察者側の表面に、粘着剤を用いて接着されてもよいし、第１の吸収型直線偏光板２２における偏光子の保護層（ＰＶＡ保護層）を兼ねるものとし、第１の吸収型直線偏光板２２に組み込んでもよい。 In this specification, “λ / 4 plate” means a birefringent body that gives a phase difference of a quarter of the wavelength λ of visible light, but at least transmits light having a wavelength of 550 nm. In this case, the optical member is not particularly limited as long as the optical member gives a phase difference of 120 to 160 nm. The first λ / 4 plate 21 may be bonded to the surface on the viewer side of the first absorption linear polarizing plate 22 using an adhesive, or the polarization in the first absorption linear polarizing plate 22. It may also serve as a child protective layer (PVA protective layer) and may be incorporated in the first absorption linear polarizing plate 22.
本実施形態では、ハーフミラープレート１０内のコレステリック液晶層と液晶パネル２０ａ内の第１のλ／４板２１を組み合わせて反射型偏光板（ハーフミラー層）を構成している。液晶パネル２０ａが表示状態となるディスプレイモードでは、コレステリック液晶層及びλ／４板を組み合わせた反射型偏光板は、第１の吸収型直線偏光板２２を透過した直線偏光を、第１のλ／４板２１によって、コレステリック液晶層を透過できる左円偏光（又は右円偏光）に変換することで液晶パネル２０ａの表示光を観察者側に透過させる。一方、液晶パネル２０ａが非表示状態となるミラーモードでは、コレステリック液晶層及びλ／４板を組み合わせた反射型偏光板は、右円偏光（又は左円偏光）の外光を観察者側に反射させるものの、第１の吸収型直線偏光板２２側から直線偏光が入射しないので、液晶パネル２０ａの表示光を観察者側に出射させることはない。以上のように、本実施形態のミラーディスプレイは、液晶パネル２０ａの表示状態に応じて、ディスプレイモード及びミラーモードが切り換わる。 In the present embodiment, a reflective polarizing plate (half mirror layer) is configured by combining the cholesteric liquid crystal layer in the half mirror plate 10 and the first λ / 4 plate 21 in the liquid crystal panel 20a. In the display mode in which the liquid crystal panel 20a is in the display state, the reflective polarizing plate combining the cholesteric liquid crystal layer and the λ / 4 plate converts the linearly polarized light transmitted through the first absorption linear polarizing plate 22 into the first λ / The four plates 21 convert the display light of the liquid crystal panel 20a to the viewer side by converting into left circularly polarized light (or right circularly polarized light) that can be transmitted through the cholesteric liquid crystal layer. On the other hand, in the mirror mode in which the liquid crystal panel 20a is in a non-display state, the reflective polarizing plate that combines the cholesteric liquid crystal layer and the λ / 4 plate reflects the external light of right circularly polarized light (or left circularly polarized light) to the viewer side. However, since the linearly polarized light does not enter from the first absorption type linear polarizing plate 22 side, the display light of the liquid crystal panel 20a is not emitted to the viewer side. As described above, in the mirror display of the present embodiment, the display mode and the mirror mode are switched according to the display state of the liquid crystal panel 20a.
第１の吸収型直線偏光板２２は、粘着剤を介してカラーフィルタ基板２３に貼り付けられ、第２の吸収型直線偏光板２６は、粘着剤を介してＴＦＴ基板２５に貼り付けられる。 The first absorption linear polarizing plate 22 is attached to the color filter substrate 23 via an adhesive, and the second absorption linear polarizing plate 26 is attached to the TFT substrate 25 via an adhesive.
第２の吸収型直線偏光板２６のバックライト３０側には反射型偏光板が積層されてもよい。また、第２の吸収型直線偏光板２６を反射型偏光板に置き換えてもよい。反射型偏光板としては、スリーエム　ジャパン社製の多層反射型偏光板（商品名：ＤＢＥＦ）や、コレステリック液晶フィルムの観察者側にλ／４板が貼り付けられた反射型偏光板を用いることができる。第２の吸収型直線偏光板２６を反射型直線偏光板に置き換えれば、第２の吸収型直線偏光板２６によって吸収されていたバックライト光が再利用されるようになるので、液晶表示の輝度を上げることができる。 A reflective polarizing plate may be laminated on the backlight 30 side of the second absorption linear polarizing plate 26. Further, the second absorption linear polarizing plate 26 may be replaced with a reflective polarizing plate. As the reflective polarizing plate, use may be made of a multilayer reflective polarizing plate (trade name: DBEF) manufactured by 3M Japan, or a reflective polarizing plate in which a λ / 4 plate is attached to the observer side of the cholesteric liquid crystal film. it can. If the second absorption type linear polarizing plate 26 is replaced with a reflection type linear polarizing plate, the backlight light absorbed by the second absorption type linear polarizing plate 26 is reused. Can be raised.
バックライト３０は、直下型であってもよいし、エッジライト型であってもよい。バックライト３０に用いられる光源は、発光ダイオード（ＬＥＤ）３１であってもよいし、蛍光管であってもよい。 The backlight 30 may be a direct type or an edge light type. The light source used for the backlight 30 may be a light emitting diode (LED) 31 or a fluorescent tube.
なお、本実施形態では、表示パネルとして液晶パネル２０ａを用いているが、本発明に適用し得る表示パネルの種類は特に限定されず、例えば、有機エレクトロルミネッセンスディスプレイ（ＯＥＬＤ：Ｏｒｇａｎｉｃ　Ｅｌｅｃｔｒｏｌｕｍｉｎｅｓｃｅｎｃｅ　Ｄｉｓｐｌａｙ）であってもよいし、プラズマディスプレイであってもよい。また、立体（３Ｄ）映像を観察することができる、いわゆる３Ｄ対応ディスプレイであってもよい。３Ｄ対応ディスプレイによれば、ミラー表示と同様にディスプレイ表示にも自然な奥行感を提供することができ、ミラーディスプレイのデザイン性を向上し、多様な用途においてミラーディスプレイを活用できる。３Ｄ対応ディスプレイの立体映像表示方式は特に限定されず任意の方式が利用できるが、メガネを必要としない裸眼方式がより好ましい。裸眼方式の３Ｄ対応ディスプレイとしては、例えば、レンチキュラーレンズ方式、視差バリア方式が挙げられる。 In the present embodiment, the liquid crystal panel 20a is used as the display panel. However, the type of the display panel applicable to the present invention is not particularly limited. For example, an organic electroluminescence display (OELD) is an organic electroluminescence display (OELD). It may be a plasma display. In addition, a so-called 3D display capable of observing a stereoscopic (3D) image may be used. According to the 3D-compatible display, a natural depth feeling can be provided for the display as well as the mirror display, the design of the mirror display can be improved, and the mirror display can be used in various applications. The stereoscopic image display method of the 3D-compatible display is not particularly limited, and any method can be used, but a naked-eye method that does not require glasses is more preferable. Examples of the naked-eye 3D display include a lenticular lens method and a parallax barrier method.
本実施形態のミラーディスプレイは、以下の利点を有するものである。
（１）コレステリック液晶層は、下記式に示すブラッグ反射条件に基づいて、斜め視角において反射帯域が短波長側にシフト（ブルーシフト）する特性を有する。
λ０＝ｎＰｃｏｓ｛ｓｉｎ－１（ｓｉｎΘ／ｎ）｝
上記式中、λ０は反射波長域の中心波長、ｎは平均屈折率、Ｐは螺旋ピッチの長さ、Θはコレステリック液晶層への入射光の入射角である。 The mirror display of this embodiment has the following advantages.
(1) The cholesteric liquid crystal layer has a characteristic that the reflection band is shifted to the short wavelength side (blue shift) at an oblique viewing angle based on the Bragg reflection condition shown in the following formula.
λ 0 = nPcos {sin −1 (sin Θ / n)}
In the above formula, λ 0 is the center wavelength of the reflection wavelength region, n is the average refractive index, P is the length of the helical pitch, and Θ is the incident angle of the incident light to the cholesteric liquid crystal layer.
上記特性のため、図２に示したように、コレステリック液晶層は、斜め視角では、反射スペクトルが短波長側にシフトする現象（ブルーシフト）を示す。図２は、コレステリック液晶層における正面視角と斜め視角の反射スペクトルを対比したグラフである。図２に示したように、ブルーシフトでの波長のシフト量は長波長側の方が大きく、長波長側では入射角が大きい場合に２００ｎｍを超える波長シフトが発生する。そのため、広い反射帯域を持つコレステリック液晶層であっても、可視光の赤領域の反射率が充分に得られず、正面視角と斜め視角で反射光の色味がずれてしまう。 Due to the above characteristics, as shown in FIG. 2, the cholesteric liquid crystal layer exhibits a phenomenon (blue shift) in which the reflection spectrum shifts to the short wavelength side at an oblique viewing angle. FIG. 2 is a graph comparing the reflection spectra of the front viewing angle and the oblique viewing angle in the cholesteric liquid crystal layer. As shown in FIG. 2, the wavelength shift amount in the blue shift is larger on the long wavelength side, and a wavelength shift exceeding 200 nm occurs when the incident angle is large on the long wavelength side. For this reason, even in the cholesteric liquid crystal layer having a wide reflection band, a sufficient reflectance in the red region of visible light cannot be obtained, and the color of the reflected light deviates between the front viewing angle and the oblique viewing angle.
これに対して、本実施形態の反射型偏光板（ハーフミラー層）は、正面視角において可視光領域に広い反射帯域を持つコレステリック液晶層（可視光反射コレステリック液晶層１３）に、正面視角において赤外光領域に反射帯域を持つコレステリック液晶層（赤外光反射コレステリック液晶層１５）を組み合わせた構成を有する。これにより、斜め視角において、ブルーシフトに起因して可視光反射コレステリック液晶層１３が失う長波長側の反射光を、赤外光反射コレステリック液晶層１５の反射光で補うことができる。よって、正面視角と斜め視角でのミラー表示の色ずれを抑制し、正面視角と斜め視角でのミラー表示の視角依存性がないミラーディスプレイを実現できる。 On the other hand, the reflective polarizing plate (half mirror layer) of the present embodiment has a cholesteric liquid crystal layer (visible light reflecting cholesteric liquid crystal layer 13) having a wide reflection band in the visible light region at the front viewing angle and red light at the front viewing angle. The cholesteric liquid crystal layer (infrared light reflecting cholesteric liquid crystal layer 15) having a reflection band in the outside light region is combined. Thereby, the reflected light on the long wavelength side lost by the visible light reflecting cholesteric liquid crystal layer 13 due to the blue shift can be supplemented by the reflected light of the infrared light reflecting cholesteric liquid crystal layer 15 at an oblique viewing angle. Accordingly, it is possible to realize a mirror display that suppresses the color shift of the mirror display at the front viewing angle and the oblique viewing angle and has no viewing angle dependency of the mirror display at the front viewing angle and the oblique viewing angle.
（２）従来のミラーディスプレイは、多層反射型偏光板や、コレステリック液晶フィルムとλ／４板を組み合わせた反射型偏光板を備えることから、明るいディスプレイ表示を得るために、軸設定が重要であった。例えば、多層反射型偏光板の場合には、多層反射型偏光板の透過軸と、液晶パネルの観察者側の吸収型偏光板の透過軸とを揃えることが望ましい。また、コレステリック液晶フィルムとλ／４板を組み合わせた反射型偏光板の場合には、λ／４板の遅相軸を、液晶パネルの観察者側の吸収型偏光板の透過軸となす角が４５°になるように調整することが望ましい。このように、従来のミラーディスプレイにおいては、ハーフミラープレートと液晶パネルとの高精度の軸設定が求められ、軸の位置がずれた場合にはディスプレイ表示光が暗くなってしまう。 (2) A conventional mirror display includes a multilayer reflective polarizing plate and a reflective polarizing plate in which a cholesteric liquid crystal film and a λ / 4 plate are combined. Therefore, in order to obtain a bright display, axis setting is important. It was. For example, in the case of a multilayer reflective polarizing plate, it is desirable to align the transmission axis of the multilayer reflective polarizing plate with the transmission axis of the absorption polarizing plate on the viewer side of the liquid crystal panel. In the case of a reflective polarizing plate in which a cholesteric liquid crystal film and a λ / 4 plate are combined, the angle between the slow axis of the λ / 4 plate and the transmission axis of the absorbing polarizing plate on the viewer side of the liquid crystal panel is It is desirable to adjust to 45 °. Thus, in the conventional mirror display, highly accurate axis setting of the half mirror plate and the liquid crystal panel is required, and the display display light becomes dark when the position of the axis is deviated.
これに対して、本実施形態では、ハーフミラープレート１０のコレステリック液晶層に対する、液晶パネル２０ａの第１のλ／４板２１の遅相軸の方向を任意に設定できる。このため、ハーフミラープレート１０と液晶パネル２０ａの間で高精度の軸設定が必要なく、位置ずれが発生した場合であっても、ディスプレイ表示光の明るさは変化しない。 In contrast, in the present embodiment, the direction of the slow axis of the first λ / 4 plate 21 of the liquid crystal panel 20a with respect to the cholesteric liquid crystal layer of the half mirror plate 10 can be arbitrarily set. For this reason, it is not necessary to set a highly accurate axis between the half mirror plate 10 and the liquid crystal panel 20a, and the brightness of the display display light does not change even when a positional deviation occurs.
（３）上記のような軸設定に関する制約があると、ハーフミラープレートに対する液晶パネルの角度を自由に変えることができないため、商品ごとに、ハーフミラープレート又は液晶パネルの透過軸方向を変更しなければならず、製造コストが増加する問題があった。一般的に、液晶パネルの直線偏光板の透過軸方向を変更することは、液晶パネル内部にまで設計変更が及ぶため、開発期間が長くなり、開発コストも増加する。そのため、ハーフミラープレートの透過軸方向を変更することがコストを削減する上で好ましい。しかしながら、後述するように、多層反射型偏光板にはサイズ制限があるため、ハーフミラープレートであっても透過軸方向には制約がある。また、液晶パネルの観察者側吸収型偏光板の透過軸がハーフミラープレートの各辺に対して傾斜する場合は、原反ロールから切り出すことができる製品の面積比率（原反ロールの採り効率）が低下するため、コストの増加に繋がる。 (3) If there are restrictions on the axis setting as described above, the angle of the liquid crystal panel with respect to the half mirror plate cannot be changed freely, so the direction of the transmission axis of the half mirror plate or liquid crystal panel must be changed for each product. In other words, there is a problem that the manufacturing cost increases. In general, changing the transmission axis direction of the linearly polarizing plate of a liquid crystal panel results in a design change extending to the inside of the liquid crystal panel, resulting in a longer development period and an increased development cost. Therefore, it is preferable to reduce the cost by changing the transmission axis direction of the half mirror plate. However, as will be described later, since the multilayer reflective polarizing plate has a size limit, there is a restriction in the transmission axis direction even in the case of a half mirror plate. In addition, when the transmission axis of the observer-side absorption polarizing plate of the liquid crystal panel is inclined with respect to each side of the half mirror plate, the area ratio of the product that can be cut out from the original fabric roll (efficiency of the original fabric roll) This leads to an increase in cost.
これに対して、本実施形態では、上記のとおり、ハーフミラープレート１０と液晶パネル２０ａの間で高精度の軸設定が必要ないことから、商品ごとに、ハーフミラープレート１０や液晶パネル２０ａの透過軸方向を変更する必要がない。よって、コレステリック液晶フィルムの原反ロールの採り効率を高くすることができ、製造コストを最小限に抑えることができる。更に、ハーフミラープレート１０に対する液晶パネル２０ａの向きを自由に変更できるので、商品開発におけるデザインの自由度も高く、ユーザーの要望に広く応えることが可能である。 On the other hand, in the present embodiment, as described above, since it is not necessary to set a highly accurate axis between the half mirror plate 10 and the liquid crystal panel 20a, transmission of the half mirror plate 10 and the liquid crystal panel 20a is performed for each product. There is no need to change the axial direction. Therefore, it is possible to increase the efficiency of taking the original roll of the cholesteric liquid crystal film, and to minimize the manufacturing cost. Furthermore, since the orientation of the liquid crystal panel 20a with respect to the half mirror plate 10 can be freely changed, the degree of freedom in design in product development is high, and it is possible to respond widely to user requests.
（４）一般的に、多層反射型偏光板は、共押出と横延伸とを組み合わせたロール・ツー・ロール方式で製造される。共押出の方法としては、フィードブロック方式や、マルチマニホールド方式が用いられる。多層反射型偏光板の製法の一例では、フィードブロック中で、多層反射型偏光板中のＡ層を構成する材料と多層反射型偏光板中のＢ層を構成する材料とを押出し、その後、マルチプライヤーを用いて多層化する。更に、得られた長尺状の多層積層体を搬送方向（ＭＤ： Ｍａｃｈｉｎｅ　Ｄｉｒｅｃｔｉｏｎ）に直交する方向（ＴＤ：Ｔｒａｎｓｖｅｒｓｅ　Ｄｉｒｅｃｔｉｏｎ）に延伸する。以上の製法によれば、Ａ層を構成する材料（例えば、ポリエチレンナフタレート）は、延伸されることで延伸方向の屈折率だけが増大し、複屈折が発現する。一方、Ｂ層を構成する材料（例えば、ナフタレンジカルボン酸とテレフタル酸とのコポリエステル）は、いずれの方向にも屈折率は増大しない。その結果として、延伸方向に反射軸を有し、搬送方向に透過軸を有する多層反射型偏光板が得られる。以上のことから、多層反射型偏光板の透過軸は、搬送方向、すなわち、多層積層体の長尺方向に平行であるため、液晶パネルの観察者側吸収型偏光板の透過軸が短辺方向にある場合には、ハーフミラープレートの長辺サイズが、多層積層体の幅サイズ（ＴＤ長さ）以下のミラーディスプレイしか製造できないことになる。 (4) Generally, a multilayer reflective polarizing plate is manufactured by a roll-to-roll method in which coextrusion and transverse stretching are combined. As a coextrusion method, a feed block method or a multi-manifold method is used. In an example of a method for producing a multilayer reflective polarizing plate, a material constituting the A layer in the multilayer reflective polarizing plate and a material constituting the B layer in the multilayer reflective polarizing plate are extruded in a feed block, Multi-layer using pliers. Furthermore, the obtained elongate multilayer laminated body is extended | stretched in the direction (TD: Transverse Direction) orthogonal to a conveyance direction (MD: Machine Direction). According to the above production method, the material constituting the A layer (for example, polyethylene naphthalate) is stretched, so that only the refractive index in the stretching direction increases and birefringence is developed. On the other hand, the material constituting the B layer (for example, copolyester of naphthalenedicarboxylic acid and terephthalic acid) does not increase the refractive index in any direction. As a result, a multilayer reflective polarizing plate having a reflection axis in the stretching direction and a transmission axis in the transport direction is obtained. From the above, since the transmission axis of the multilayer reflective polarizing plate is parallel to the transport direction, that is, the long direction of the multilayer laminate, the transmission axis of the observer-side absorption polarizing plate of the liquid crystal panel is the short side direction. In this case, only the mirror display in which the long side size of the half mirror plate is equal to or smaller than the width size (TD length) of the multilayer laminate can be manufactured.
これに対して、本実施形態では、ハーフミラープレート１０内のコレステリック液晶層と液晶パネル２０ａ内の第１のλ／４板２１を組み合わせて反射型偏光板を構成している。この場合、第１のλ／４板２１の遅相軸の方向を任意に設定でき、多層反射型偏光板を用いる場合よりも大きなミラーディスプレイの製造が可能である。また、透明基板１１上にコレステリック液晶樹脂層を形成する場合は、長尺状のフィルムから個々のコレステリック液晶フィルムを切り出すプロセスを行わないため、更に大きなサイズや、フィルム加工による成形が難しい異形のミラーディスプレイの製造が可能である。 On the other hand, in the present embodiment, a reflective polarizing plate is configured by combining the cholesteric liquid crystal layer in the half mirror plate 10 and the first λ / 4 plate 21 in the liquid crystal panel 20a. In this case, the direction of the slow axis of the first λ / 4 plate 21 can be set arbitrarily, and a larger mirror display can be manufactured than when a multilayer reflective polarizing plate is used. Further, when forming a cholesteric liquid crystal resin layer on the transparent substrate 11, a process of cutting out individual cholesteric liquid crystal films from a long film is not performed, so that a mirror having a larger size or a deformed mirror that is difficult to form by film processing is used. A display can be manufactured.
（５）多層反射型偏光板は、出射光が直線偏光であるため、偏光サングラスを掛けた状態では、ディスプレイ表示光の見え方が暗くなる問題がある。この問題に対して、例えば、特許文献７には、多層反射型偏光板の透過軸と、λ／４板の遅相軸のなす角が４５°となるように、多層反射偏光板の観察者側の面にλ／４板を貼り付ける方法が提案されている。しかしながら、上記方法では、出射光を円偏光とするために、多層反射偏光板の透過軸とλ／４板の遅相軸を高精度で貼り合わせる必要があるほか、工数増加に伴うコストの増加の問題がある。 (5) The multilayer reflection type polarizing plate has a problem that the appearance of the display light becomes dark when the polarized light is put on since the emitted light is linearly polarized light. To solve this problem, for example, Patent Document 7 discloses an observer of a multilayer reflective polarizing plate so that the angle formed by the transmission axis of the multilayer reflective polarizing plate and the slow axis of the λ / 4 plate is 45 °. A method of attaching a λ / 4 plate to the side surface has been proposed. However, in the above method, in order to make the emitted light circularly polarized, it is necessary to bond the transmission axis of the multilayer reflective polarizing plate and the slow axis of the λ / 4 plate with high accuracy, and the cost increases as the number of steps increases. There is a problem.
これに対して、本実施形態では、ハーフミラープレート１０内のコレステリック液晶層と液晶パネル２０ａ内の第１のλ／４板２１を組み合わせて反射型偏光板を構成している。この場合、観察者側に配置されるコレステリック液晶層からの出射光は円偏光なので、偏光サングラスに対する対策は必要ない。よって、λ／４板を追加することによるコストの増加は生じない。 On the other hand, in the present embodiment, a reflective polarizing plate is configured by combining the cholesteric liquid crystal layer in the half mirror plate 10 and the first λ / 4 plate 21 in the liquid crystal panel 20a. In this case, since the emitted light from the cholesteric liquid crystal layer disposed on the observer side is circularly polarized, no countermeasure against polarized sunglasses is required. Therefore, an increase in cost due to the addition of the λ / 4 plate does not occur.
（６）近年のスマートフォン、タブレット、車載用途の中小型液晶ディスプレイは、偏光サングラスを掛けた状態でもディスプレイ表示が見えるように、出射光が円偏光となるように設計されることがある。一般的に、液晶ディスプレイで用いられる吸収型偏光板は、ポリビニルアルコール（ＰＶＡ）染色延伸フィルム偏光子と、トリアセチルセルロース（ＴＡＣ）保護層からなる直線偏光板であり、ディスプレイから出射される光は直線偏光である。直線偏光板を円偏光板にする方法としては、直線偏光板の吸収軸と、λ／４板の遅相軸のなす角が４５°となるように、直線偏光板にλ／４板を貼り付ける方法がある。上記の方法では、直線偏光板とλ／４板をそれぞれ所定の形状に裁断又は打ち抜く工程や、直線偏光板にλ／４板を貼り合せる工程を含むため、工程数が多い。そのため、異物が層間に混入する可能性が高く、異物による不具合の発生や、透過率や偏光度が低下する問題があった。この問題に対して、ＴＡＣ保護層の代わりにλ／４板を保護層とし、ＰＶＡ染色延伸フィルム偏光子とλ／４板とを接着層を介して一体化した円偏光板も提案されている（特許文献１３及び１４参照）。しかしながら、多層反射型偏光板や、コレステリック液晶フィルムとλ／４板を組み合わせた反射型偏光板を用いたハーフミラープレートは、円偏光の透過率が低いため、偏光サングラス対策が施された円偏光を出射する中小型液晶ディスプレイと組み合わせて用いると、ミラーディスプレイの表示光が暗くなる問題があった。 (6) Recent small- and medium-sized liquid crystal displays for smartphones, tablets, and in-vehicle applications may be designed so that the emitted light is circularly polarized so that the display can be seen even when wearing polarized sunglasses. In general, the absorption polarizing plate used in a liquid crystal display is a linear polarizing plate made of a polyvinyl alcohol (PVA) dyed stretched film polarizer and a triacetyl cellulose (TAC) protective layer, and the light emitted from the display is Linearly polarized light. As a method of making the linearly polarizing plate into a circularly polarizing plate, the λ / 4 plate is attached to the linearly polarizing plate so that the angle formed by the absorption axis of the linearly polarizing plate and the slow axis of the λ / 4 plate is 45 °. There is a way to put it. The above method includes a process of cutting or punching the linearly polarizing plate and the λ / 4 plate into a predetermined shape and a process of bonding the λ / 4 plate to the linearly polarizing plate, so that the number of processes is large. For this reason, there is a high possibility that foreign matter is mixed between the layers, and there are problems of occurrence of defects due to the foreign matter and a decrease in transmittance and polarization degree. In order to solve this problem, there has also been proposed a circularly polarizing plate in which a λ / 4 plate is used as a protective layer instead of the TAC protective layer, and the PVA dyed stretched film polarizer and the λ / 4 plate are integrated through an adhesive layer. (See Patent Documents 13 and 14). However, half-mirror plates that use multilayer reflective polarizing plates or reflective polarizing plates that combine a cholesteric liquid crystal film and a λ / 4 plate have low circularly polarized light transmittance. When used in combination with a medium- and small-sized liquid crystal display that emits light, the display light of the mirror display becomes dark.
これに対して、本実施形態では、ハーフミラープレート１０内のコレステリック液晶層と液晶パネル２０ａ内の第１のλ／４板２１を組み合わせて反射型偏光板を構成している。この場合、ハーフミラープレート１０における円偏光の透過率が高いため、ディスプレイ表示の明るいミラーディスプレイが製造可能である。 On the other hand, in the present embodiment, a reflective polarizing plate is configured by combining the cholesteric liquid crystal layer in the half mirror plate 10 and the first λ / 4 plate 21 in the liquid crystal panel 20a. In this case, since the transmittance of the circularly polarized light in the half mirror plate 10 is high, a bright mirror display can be manufactured.
以上をまとめると、本実施形態のミラーディスプレイの利点は、以下のとおりである。
・観察者の見る角度によるミラー表示の反射色の変化が抑制されたミラーディスプレイを実現できる。
・ハーフミラープレート１０と液晶パネル２０ａの細かな軸設定が必要なく、位置ずれが発生した場合であってもディスプレイ表示光の明るさが変化しない。
・観察者が偏光サングラスを掛けた状態でもディスプレイ表示光が極端に暗くなることがない。
・小型～大型サイズまでのミラーディスプレイを低コストで製造できる。したがって、モバイル、車載ルームミラー用途の小型ミラーディスプレイから、デジタルサイネージ用途の大型ミラーディスプレイまで、広範囲の用途に適用できる。 In summary, the advantages of the mirror display of the present embodiment are as follows.
-It is possible to realize a mirror display in which the change in the reflected color of the mirror display depending on the viewing angle of the observer is suppressed.
-Fine axis setting of the half mirror plate 10 and the liquid crystal panel 20a is not necessary, and the brightness of the display light does not change even when a positional deviation occurs.
-Display light does not become extremely dark even when the observer is wearing polarized sunglasses.
-Small to large size mirror displays can be manufactured at low cost. Therefore, it can be applied to a wide range of applications from a small mirror display for mobile and in-vehicle room mirrors to a large mirror display for digital signage.
以下に実施例及び比較例を掲げて本発明を更に詳細に説明するが、本発明はこれらの実施例のみに限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.
（可視光反射コレステリック液晶フィルムの製造）
実施例及び比較例で使用した可視光反射コレステリック液晶フィルムは、下記（Ａ１）～（Ａ６）の工程を実施することで製造した。
（Ａ１）下記化学式（１）の重合性液晶化合物９４．８重量部、カイラル剤（ＢＡＳＦ社製、「ＬＣ７５６」）５．２重量部、及び、光重合開始剤（ＢＡＳＦ社製、「ＩＲＧＡＣＵＲＥ９０７」）３．０重量部の混合物を、固形分濃度３０重量％となるようにシクロペンタノンに溶解させることで、重合性溶液を得る。 (Manufacture of visible light reflective cholesteric liquid crystal film)
Visible light reflective cholesteric liquid crystal films used in Examples and Comparative Examples were produced by carrying out the following steps (A1) to (A6).
(A1) 94.8 parts by weight of a polymerizable liquid crystal compound of the following chemical formula (1), 5.2 parts by weight of a chiral agent (“LC756” manufactured by BASF), and a photopolymerization initiator (“IRGACURE907” manufactured by BASF) ) A polymerizable solution is obtained by dissolving 3.0 parts by weight of the mixture in cyclopentanone so as to have a solid concentration of 30% by weight.
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
（Ａ２）延伸ＰＥＴ（ポリエチレンテレフタレート）フィルムに、上記の重合性溶液を塗布する。
（Ａ３）塗布された重合性溶液を１００℃で２分間焼成し、乾燥させる。
（Ａ４）４０℃の空気雰囲気下にて、延伸ＰＥＴフィルム側から照射エネルギー４０ｍＷ／ｃｍ２で、１．２秒間紫外線を照射する。
（Ａ５）３℃／秒の昇温速度で９０℃まで昇温した後、９０℃の空気雰囲気下で、２０秒間加熱する。
（Ａ６）５０℃の窒素雰囲気下にて、延伸ＰＥＴフィルム側から、照射エネルギー６０ｍＷ／ｃｍ２で、１０秒間紫外線を照射する。 (A2) The polymerizable solution is applied to a stretched PET (polyethylene terephthalate) film.
(A3) The applied polymerizable solution is baked at 100 ° C. for 2 minutes and dried.
(A4) In an air atmosphere at 40 ° C., ultraviolet rays are irradiated from the stretched PET film side at an irradiation energy of 40 mW / cm 2 for 1.2 seconds.
(A5) The temperature is raised to 90 ° C. at a rate of 3 ° C./second, and then heated for 20 seconds in an air atmosphere at 90 ° C.
(A6) In a nitrogen atmosphere at 50 ° C., ultraviolet rays are irradiated from the stretched PET film side at an irradiation energy of 60 mW / cm 2 for 10 seconds.
上記製法で製造された可視光反射コレステリック液晶フィルムの正面視角での反射帯域は、波長４１５～７１０ｎｍであった。 The reflection band at the front viewing angle of the visible light reflective cholesteric liquid crystal film produced by the above production method was a wavelength of 415 to 710 nm.
（赤外光反射コレステリック液晶フィルムの製造）
実施例で使用した赤外光反射コレステリック液晶フィルムは、下記（Ｂ１）～（Ｂ３）の工程を実施することで製造した。
（Ｂ１）重合性液晶化合物（ＢＡＳＦ社製、「ＬＣ２４２」）９７．５重量部、カイラル剤（ＢＡＳＦ社製、「ＬＣ７５６」）２．５重量部、及び、熱重合開始剤（和光純薬工業社製、「Ｖ－６５」）１．０重量部の混合物を、固形分濃度３０重量％となるようにシクロペンタノンに溶解させることで、重合性溶液を得る。
（Ｂ２）延伸ＰＥＴフィルムに、上記の重合性溶液を塗布する。
（Ｂ３）酸素を０．５体積％含有する窒素ガス雰囲気下で、１００℃で１０分間加熱する。 (Manufacture of infrared light reflecting cholesteric liquid crystal film)
The infrared light reflecting cholesteric liquid crystal film used in the examples was manufactured by performing the following steps (B1) to (B3).
(B1) 97.5 parts by weight of a polymerizable liquid crystal compound (manufactured by BASF, “LC242”), 2.5 parts by weight of a chiral agent (manufactured by BASF, “LC756”), and a thermal polymerization initiator (Wako Pure Chemical Industries, Ltd.) A polymerizable solution is obtained by dissolving 1.0 part by weight of a mixture (manufactured by “V-65”) in cyclopentanone so as to have a solid concentration of 30% by weight.
(B2) The polymerizable solution is applied to the stretched PET film.
(B3) Heat at 100 ° C. for 10 minutes in a nitrogen gas atmosphere containing 0.5% by volume of oxygen.
上記製法で製造された赤外光反射コレステリック液晶フィルムの正面視角での反射帯域は、７１０～１１８０ｎｍであった。 The reflection band at the front viewing angle of the infrared light-reflecting cholesteric liquid crystal film produced by the above production method was 710 to 1180 nm.
（可視光反射コレステリック液晶樹脂層の製造）
実施例及び比較例で使用した可視光反射コレステリック液晶樹脂層は、重合性溶液を塗布する基材をガラス基板としたこと以外は、上記の可視光反射コレステリック液晶フィルムの製造方法と同様の方法にて作製した。 (Manufacture of visible light reflecting cholesteric liquid crystal resin layer)
The visible light reflective cholesteric liquid crystal resin layer used in the examples and comparative examples is the same as the above-described method for producing a visible light reflective cholesteric liquid crystal film, except that the substrate on which the polymerizable solution is applied is a glass substrate. Made.
（粘着剤）
実施例及び比較例で使用した粘着剤は、パナック社製の「ＰＤ－Ｓ１」であった。 (Adhesive)
The pressure-sensitive adhesive used in Examples and Comparative Examples was “PD-S1” manufactured by Panac Corporation.
（実施例１）
図３に示した構成を有するミラーディスプレイを作製した。図３は、実施例１に係るミラーディスプレイの構成を示す断面模式図である。まず、延伸ＰＥＴフィルム付きの可視光反射コレステリック液晶フィルム１３ａを、粘着剤を用いて、ガラス基板１１に貼り付けた。次いで、可視光反射コレステリック液晶フィルム１３ａから延伸ＰＥＴフィルムを剥離し、露出した面に、延伸ＰＥＴフィルム付きの赤外光反射コレステリック液晶フィルム１５ａを、粘着剤を用いて貼り付けた。その後、赤外光反射コレステリック液晶フィルム１５ａから延伸ＰＥＴフィルムを剥離することによって、実施例１のハーフミラープレート１０ａが完成した。 Example 1
A mirror display having the configuration shown in FIG. 3 was produced. FIG. 3 is a schematic cross-sectional view illustrating the configuration of the mirror display according to the first embodiment. First, the visible light reflective cholesteric liquid crystal film 13a with a stretched PET film was attached to the glass substrate 11 using an adhesive. Next, the stretched PET film was peeled from the visible light reflective cholesteric liquid crystal film 13a, and the infrared light reflective cholesteric liquid crystal film 15a with the stretched PET film was attached to the exposed surface using an adhesive. Then, the half mirror plate 10a of Example 1 was completed by peeling a stretched PET film from the infrared light reflection cholesteric liquid crystal film 15a.
５型のフルハイビジョン（ＦＨＤ）液晶モジュール（シャープ社製）を液晶パネル２０ａとバックライト３０に分解し、液晶パネル２０ａの、観察者側に位置する第１の吸収型直線偏光板２２の上に、第１のλ／４板２１（日本ゼオン社製、「ＺＤフィルム」）を貼り付けた。このとき、第１の吸収型直線偏光板２２の透過軸と第１のλ／４板２１の遅相軸とのなす角が４５°になるように調整した。そして、観測者側からハーフミラープレート１０ａ、液晶パネル２０ａ、バックライト３０の順になるように、筐体に組み込んだ。このとき、ハーフミラープレート１０ａにおいてガラス基板１１よりも可視光反射コレステリック液晶フィルム１３ａ及び赤外光反射コレステリック液晶フィルム１５ａが液晶パネル２０ａに近くなるように調整した。
以上の工程を経ることで、実施例１のミラーディスプレイを作製した。 A 5-inch full high-definition (FHD) liquid crystal module (manufactured by Sharp) is disassembled into a liquid crystal panel 20a and a backlight 30, and the liquid crystal panel 20a is placed on the first absorption type linear polarizing plate 22 located on the viewer side. First λ / 4 plate 21 (manufactured by Nippon Zeon Co., Ltd., “ZD film”) was attached. At this time, the angle between the transmission axis of the first absorption type linear polarizing plate 22 and the slow axis of the first λ / 4 plate 21 was adjusted to 45 °. And it assembled in the housing | casing so that it might become the order of the half mirror plate 10a, the liquid crystal panel 20a, and the backlight 30 from the observer side. At this time, the visible light reflecting cholesteric liquid crystal film 13a and the infrared light reflecting cholesteric liquid crystal film 15a were adjusted closer to the liquid crystal panel 20a than the glass substrate 11 in the half mirror plate 10a.
By passing through the above process, the mirror display of Example 1 was produced.
（実施例２）
図４に示した構成を有するミラーディスプレイを作製した。図４は、実施例２に係るミラーディスプレイの構成を示す断面模式図である。まず、ガラス基板１１上に直接、可視光反射コレステリック液晶樹脂層１３ｂを形成した。次いで、延伸ＰＥＴフィルム付きの赤外光反射コレステリック液晶フィルム１５ａを、粘着剤を用いて、可視光反射コレステリック液晶樹脂層１３ｂ上に貼り付けた。その後、赤外光反射コレステリック液晶フィルム１５ａから延伸ＰＥＴフィルムを剥離することによって、実施例２のハーフミラープレート１０ｂが完成した。
以上のハーフミラープレート１０ｂの製造工程以外は、実施例１と同様にして、実施例２のミラーディスプレイを作製した。 (Example 2)
A mirror display having the configuration shown in FIG. 4 was produced. FIG. 4 is a schematic cross-sectional view illustrating the configuration of the mirror display according to the second embodiment. First, the visible light reflecting cholesteric liquid crystal resin layer 13 b was formed directly on the glass substrate 11. Next, an infrared light reflecting cholesteric liquid crystal film 15a with a stretched PET film was attached onto the visible light reflecting cholesteric liquid crystal resin layer 13b using an adhesive. Then, the half mirror plate 10b of Example 2 was completed by peeling a stretched PET film from the infrared light reflection cholesteric liquid crystal film 15a.
A mirror display of Example 2 was produced in the same manner as Example 1 except for the manufacturing process of the half mirror plate 10b described above.
（実施例３）
図５に示した構成を有するミラーディスプレイを作製した。図５は、実施例３に係るミラーディスプレイの構成を示す断面模式図である。液晶パネル２０ｂにおいて、第２の吸収型直線偏光板２６のバックライト３０側に、粘着剤を用いて、反射型直線偏光板２７（スリーエム　ジャパン社製、「ＤＢＥＦ」）を貼り付けた。上記以外は、実施例１と同様の工程を経て、実施例３のミラーディスプレイを作製した。 (Example 3)
A mirror display having the configuration shown in FIG. 5 was produced. FIG. 5 is a schematic cross-sectional view illustrating the configuration of the mirror display according to the third embodiment. In the liquid crystal panel 20b, a reflective linear polarizing plate 27 (manufactured by 3M Japan, “DBEF”) was attached to the backlight 30 side of the second absorption linear polarizing plate 26 using an adhesive. Except for the above, the mirror display of Example 3 was produced through the same steps as in Example 1.
（実施例４）
図６に示した構成を有するミラーディスプレイを作製した。図６は、実施例４に係るミラーディスプレイの構成を示す断面模式図である。液晶パネル２０ｃにおいて、第２の吸収型直線偏光板２６のバックライト３０側に、粘着剤を用いて、第２のλ／４板２８（日本ゼオン社製、「ＺＤフィルム」）と、延伸ＰＥＴフィルム付きの第２の可視光反射コレステリック液晶フィルム２９とを順に貼付し、第２の可視光反射コレステリック液晶フィルム２９から延伸ＰＥＴフィルムを剥離した。上記以外は、実施例１と同様の工程を経て、実施例４のミラーディスプレイを作製した。 (Example 4)
A mirror display having the configuration shown in FIG. 6 was produced. FIG. 6 is a schematic cross-sectional view illustrating the configuration of the mirror display according to the fourth embodiment. In the liquid crystal panel 20c, the second λ / 4 plate 28 (manufactured by Zeon Corporation, “ZD film”) and stretched PET are used on the backlight 30 side of the second absorption linear polarizing plate 26 using an adhesive. A second visible light reflecting cholesteric liquid crystal film 29 with a film was attached in order, and the stretched PET film was peeled from the second visible light reflecting cholesteric liquid crystal film 29. Except for the above, the mirror display of Example 4 was produced through the same steps as in Example 1.
（実施例５）
図７に示した構成を有するミラーディスプレイを作製した。図７は、実施例５に係るミラーディスプレイの構成を示す断面模式図である。図３の液晶パネル２０ａから第２の吸収型直線偏光板２６を剥がした後、残った粘着剤をアセトンで拭き取った。その後、ＴＦＴ基板２５のバックライト３０側に、粘着剤を用いて、反射型直線偏光板２７（スリーエム　ジャパン社製、「ＤＢＥＦ」）を貼り付け、液晶パネル２０ｄを作製した。上記以外は、実施例１と同様の工程を経て、実施例５のミラーディスプレイを作製した。 (Example 5)
A mirror display having the configuration shown in FIG. 7 was produced. FIG. 7 is a schematic cross-sectional view illustrating the configuration of the mirror display according to the fifth embodiment. After peeling off the second absorption type linearly polarizing plate 26 from the liquid crystal panel 20a of FIG. 3, the remaining adhesive was wiped off with acetone. Thereafter, a reflective linearly polarizing plate 27 (manufactured by 3M Japan, “DBEF”) was attached to the backlight 30 side of the TFT substrate 25 using an adhesive to produce a liquid crystal panel 20d. Except for the above, the mirror display of Example 5 was produced through the same steps as in Example 1.
（実施例６）
図８に示した構成を有するミラーディスプレイを作製した。図８は、実施例６に係るミラーディスプレイの構成を示す断面模式図である。図３の液晶パネル２０ａから第２の吸収型直線偏光板２６を剥がした後、残った粘着剤をアセトンで拭き取った。その後、ＴＦＴ基板２５のバックライト３０側に、粘着剤を用いて、 第２のλ／４板２８（日本ゼオン社製、「ＺＤフィルム」）と、延伸ＰＥＴフィルム付きの第２の可視光反射コレステリック液晶フィルム２９とを順に貼付し、第２の可視光反射コレステリック液晶フィルム２９から延伸ＰＥＴフィルムを剥離し、液晶パネル２０ｅを作製した。上記以外は、実施例１と同様の工程を経て、実施例６のミラーディスプレイを作製した。 (Example 6)
A mirror display having the configuration shown in FIG. 8 was produced. FIG. 8 is a schematic cross-sectional view illustrating the configuration of the mirror display according to the sixth embodiment. After peeling off the second absorption type linearly polarizing plate 26 from the liquid crystal panel 20a of FIG. 3, the remaining adhesive was wiped off with acetone. Thereafter, a second λ / 4 plate 28 (manufactured by Nippon Zeon Co., Ltd., “ZD film”) and a second visible light reflection with a stretched PET film are used on the backlight 30 side of the TFT substrate 25. A cholesteric liquid crystal film 29 was attached in order, and the stretched PET film was peeled off from the second visible light reflecting cholesteric liquid crystal film 29 to prepare a liquid crystal panel 20e. Except for the above, the mirror display of Example 6 was produced through the same steps as in Example 1.
（比較例１）
図９に示した構成を有するミラーディスプレイを作製した。図９は、比較例１に係るミラーディスプレイの構成を示す断面模式図である。ガラス基板６１に粘着剤を用いて反射型直線偏光板６２（スリーエム　ジャパン社製、「ＤＢＥＦ」）を貼り付けることによって、比較例１のハーフミラープレート６０ａを作製した。また、実施例１で用いた５型のフルハイビジョン（ＦＨＤ）液晶モジュール（シャープ社製）を分解せずにそのまま用いた。すなわち、実施例１の液晶パネル２０ａでは、第１のλ／４板２１が設けられたが、比較例１の液晶パネル７０ａでは、第１の吸収型直線偏光板２２の上には何も貼り付けられなかった。上記以外は、実施例１と同様の工程を経て、比較例１のミラーディスプレイを作製した。 (Comparative Example 1)
A mirror display having the configuration shown in FIG. 9 was produced. FIG. 9 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Comparative Example 1. A half-mirror plate 60a of Comparative Example 1 was prepared by attaching a reflective linearly polarizing plate 62 (manufactured by 3M Japan, “DBEF”) to the glass substrate 61 using an adhesive. Further, the 5-inch full high vision (FHD) liquid crystal module (manufactured by Sharp) used in Example 1 was used as it was without being disassembled. That is, the first λ / 4 plate 21 is provided in the liquid crystal panel 20a of the first embodiment, but nothing is pasted on the first absorption type linear polarizing plate 22 in the liquid crystal panel 70a of the first comparative example. It was not attached. Except for the above, the mirror display of Comparative Example 1 was produced through the same steps as in Example 1.
（比較例２）
図１０に示した構成を有するミラーディスプレイを作製した。図１０は、比較例２に係るミラーディスプレイの構成を示す断面模式図である。ガラス基板６１に粘着剤を用いて、延伸ＰＥＴフィルム付きの可視光反射コレステリック液晶フィルム６３ａを貼り付けた。その後、可視光反射コレステリック液晶フィルム６３ａから延伸ＰＥＴフィルムを剥離した。次いで、可視光反射コレステリック液晶フィルム６３ａに粘着剤を用いて λ／４板６４（日本ゼオン社製、「ＺＤフィルム」）を貼り付けることによって、比較例２のハーフミラープレート６０ｂを作製した。上記以外は、比較例１と同様の工程を経て、比較例２のミラーディスプレイを作製した。 (Comparative Example 2)
A mirror display having the configuration shown in FIG. 10 was produced. FIG. 10 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Comparative Example 2. A visible light reflective cholesteric liquid crystal film 63a with a stretched PET film was attached to the glass substrate 61 using an adhesive. Thereafter, the stretched PET film was peeled from the visible light reflecting cholesteric liquid crystal film 63a. Subsequently, the half mirror plate 60b of the comparative example 2 was produced by affixing (lambda) / 4 board 64 (made by Nippon Zeon Co., Ltd., "ZD film") to the visible light reflection cholesteric liquid crystal film 63a using an adhesive. Except for the above, the mirror display of Comparative Example 2 was produced through the same steps as in Comparative Example 1.
（比較例３）
図１１に示した構成を有するミラーディスプレイを作製した。図１１は、比較例３に係るミラーディスプレイの構成を示す断面模式図である。ガラス基板６１に粘着剤を用いて、λ／４板６４（日本ゼオン社製、「ＺＤフィルム」）と、反射型直線偏光板６２（スリーエム　ジャパン社製、「ＤＢＥＦ」）を順に貼り付けることによって、比較例３のハーフミラープレート６０ｃを作製した。上記以外は、比較例１と同様の工程を経て、比較例３のミラーディスプレイを作製した。 (Comparative Example 3)
A mirror display having the configuration shown in FIG. 11 was produced. FIG. 11 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Comparative Example 3. By sticking a λ / 4 plate 64 (manufactured by Nippon Zeon Co., Ltd., “ZD film”) and a reflective linear polarizing plate 62 (manufactured by 3M Japan Co., Ltd., “DBEF”) in order using an adhesive on the glass substrate 61. A half mirror plate 60c of Comparative Example 3 was produced. Except for the above, the mirror display of Comparative Example 3 was produced through the same steps as in Comparative Example 1.
（比較例４）
図１２に示した構成を有するミラーディスプレイを作製した。図１２は、比較例４に係るミラーディスプレイの構成を示す断面模式図である。ガラス基板６１に粘着剤を用いて、延伸ＰＥＴフィルム付きの可視光反射コレステリック液晶フィルム６３ａを貼り付けた。次いで、可視反射コレステリック液晶フィルム６３ａから延伸ＰＥＴフィルムを剥離することによって、比較例４のハーフミラープレート６０ｄが完成した。
以上のハーフミラープレートの製造工程以外は、実施例１と同様にして、比較例４のミラーディスプレイを作製した。 (Comparative Example 4)
A mirror display having the configuration shown in FIG. 12 was produced. FIG. 12 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Comparative Example 4. A visible light reflective cholesteric liquid crystal film 63a with a stretched PET film was attached to the glass substrate 61 using an adhesive. Next, the stretched PET film was peeled off from the visible reflective cholesteric liquid crystal film 63a to complete the half mirror plate 60d of Comparative Example 4.
A mirror display of Comparative Example 4 was produced in the same manner as in Example 1 except for the manufacturing process of the half mirror plate described above.
（比較例５）
図１３に示した構成を有するミラーディスプレイを作製した。図１３は、比較例５に係るミラーディスプレイの構成を示す断面模式図である。ガラス基板６１上に直接、可視光反射コレステリック液晶樹脂層６３ｂを形成することによって、比較例５のハーフミラープレート６０ｅを作製したこと以外は、比較例４と同様の工程を経て、比較例５のミラーディスプレイを作製した。 (Comparative Example 5)
A mirror display having the configuration shown in FIG. 13 was produced. FIG. 13 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Comparative Example 5. Except that the half mirror plate 60e of Comparative Example 5 was produced by directly forming the visible light reflecting cholesteric liquid crystal resin layer 63b on the glass substrate 61, the same process as in Comparative Example 4 was performed. A mirror display was produced.
（比較例６）
図１４に示した構成を有するミラーディスプレイを作製した。図１４は、比較例６に係るミラーディスプレイの構成を示す断面模式図である。比較例６に係るミラーディスプレイは、偏光サングラス対策として、λ／４板一体型円偏光板７３を備える。具体的には、実施例１の液晶パネル２０ａでは、第１のλ／４板２１と第１の吸収型直線偏光板２２とが独立して設けられたが、比較例６の液晶パネル７０ｂでは、観察者側から順にλ／４板７１及び吸収型直線偏光板７２を有する積層体であるλ／４板一体型円偏光板７３が観察者側に設けられた。上記以外は、比較例４と同様の工程を経て、比較例６のミラーディスプレイを作製した。 (Comparative Example 6)
A mirror display having the configuration shown in FIG. 14 was produced. FIG. 14 is a schematic cross-sectional view illustrating a configuration of a mirror display according to Comparative Example 6. The mirror display according to Comparative Example 6 includes a λ / 4 plate-integrated circularly polarizing plate 73 as a countermeasure against polarized sunglasses. Specifically, in the liquid crystal panel 20a of Example 1, the first λ / 4 plate 21 and the first absorption linear polarizing plate 22 are provided independently, but in the liquid crystal panel 70b of Comparative Example 6, A λ / 4 plate-integrated circularly polarizing plate 73, which is a laminate including the λ / 4 plate 71 and the absorption linearly polarizing plate 72, was provided on the viewer side. Except for the above, the mirror display of Comparative Example 6 was produced through the same steps as in Comparative Example 4.
（評価試験）
実施例及び比較例で作製したミラーディスプレイについて、以下の評価試験を実施した。 (Evaluation test)
The following evaluation test was implemented about the mirror display produced by the Example and the comparative example.
（評価試験１）
ハーフミラープレートを液晶パネルから取り外し、バックライトを点灯し、かつ液晶パネルを白表示させた状態で、液晶パネルに対してハーフミラープレートを回転させながら、輝度を測定した。ハーフミラープレートの初期位置を０°とし、そこから４５°及び９０°回転させた。輝度は、トプコン社製の分光放射計「ＳＲ－ＵＬ１」によって測定した。 (Evaluation Test 1)
The brightness was measured while removing the half mirror plate from the liquid crystal panel, turning on the backlight, and displaying the white color on the liquid crystal panel while rotating the half mirror plate with respect to the liquid crystal panel. The initial position of the half mirror plate was set to 0 °, and rotated 45 ° and 90 ° therefrom. The luminance was measured with a spectroradiometer “SR-UL1” manufactured by Topcon Corporation.
上記評価試験１の結果を表１に示す。表１に示したように、比較例１～３のミラーディスプレイは、ハーフミラープレートを回転することで輝度が大きく変化した。一方、実施例１～６及び比較例４～６のミラーディスプレイは、ハーフミラープレートを回転してもほとんど輝度が変化しなかった。評価試験１の結果から、比較例１～３のミラーディスプレイは、ハーフミラープレートと液晶パネルの位置ずれによって輝度が変化しやすいことが分かった。 The results of the evaluation test 1 are shown in Table 1. As shown in Table 1, the brightness of the mirror displays of Comparative Examples 1 to 3 was greatly changed by rotating the half mirror plate. On the other hand, in the mirror displays of Examples 1 to 6 and Comparative Examples 4 to 6, the luminance hardly changed even when the half mirror plate was rotated. From the results of Evaluation Test 1, it was found that the brightness of the mirror displays of Comparative Examples 1 to 3 was likely to change due to the misalignment between the half mirror plate and the liquid crystal panel.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
（評価試験２）
偏光サングラスを掛けた状態で、ミラーディスプレイを観察し、ディスプレイ表示が見えるか否かを確認した。 (Evaluation test 2)
While wearing polarized sunglasses, the mirror display was observed to check whether the display was visible.
上記評価試験２の結果を表２に示す。表２に示したように、比較例１のミラーディスプレイではディスプレイ表示が見えなかった。一方、実施例１～６及び比較例２～６のミラーディスプレイは、ディスプレイ表示が問題なく見えた。 The results of the evaluation test 2 are shown in Table 2. As shown in Table 2, the display on the mirror display of Comparative Example 1 was not visible. On the other hand, in the mirror displays of Examples 1 to 6 and Comparative Examples 2 to 6, the display display seemed without problems.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
（評価試験３）
ミラーディスプレイの電源を切った状態で机に固定し、ハーフミラープレートの法線方向（正面視角）と、法線方向から７０度視角を倒した状態（斜め視角）で反射色に違いがあるか否かを目視にて確認した。なお、本評価試験は、実施例１～６及び比較例２、４、５、６のミラーディスプレイについて実施した。 (Evaluation Test 3)
If the mirror display is turned off and fixed to the desk, is there a difference in reflected color between the normal direction (frontal viewing angle) of the half mirror plate and the 70 ° viewing angle (oblique viewing angle) from the normal direction? It was confirmed visually. This evaluation test was performed on the mirror displays of Examples 1 to 6 and Comparative Examples 2, 4, 5, and 6.
上記評価試験３の結果を表３に示す。表３に示したように、赤外光反射コレステリック液晶フィルムを積層した実施例１～６のミラーディスプレイでは、反射色の違いが無かった。 The results of the evaluation test 3 are shown in Table 3. As shown in Table 3, in the mirror displays of Examples 1 to 6 in which the infrared light reflecting cholesteric liquid crystal film was laminated, there was no difference in the reflection color.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
（評価試験４）
ミラーディスプレイを、電源を切った状態で机の上に固定し、ハーフミラープレートに映り込んだ天井の蛍光灯の像のエッジの鮮明さを目視にて確認した。なお、本評価試験は、実施例１、２及び比較例４、５のミラーディスプレイについて実施した。上記評価試験４の結果を表４に示す。 (Evaluation Test 4)
The mirror display was fixed on the desk with the power turned off, and the sharpness of the edge of the fluorescent lamp image reflected on the half mirror plate was visually confirmed. In addition, this evaluation test was implemented about the mirror display of Examples 1, 2 and Comparative Examples 4, 5. The results of the evaluation test 4 are shown in Table 4.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
（評価試験５）
ミラーディスプレイの輝度を測定し、液晶パネルとバックライト間に反射型偏光板を挿入することによる輝度向上効果を確認した。なお、本評価試験では、実施例１のミラーディスプレイを基準とし、実施例３～６のミラーディスプレイについて輝度向上効果を算出した。 (Evaluation Test 5)
The brightness of the mirror display was measured, and the brightness improvement effect by inserting a reflective polarizing plate between the liquid crystal panel and the backlight was confirmed. In this evaluation test, the brightness improvement effect was calculated for the mirror displays of Examples 3 to 6, using the mirror display of Example 1 as a reference.
実施例３～６のミラーディスプレイはいずれも、実施例１のミラーディスプレイに対して、１．２倍以上の輝度向上効果を示した。また、実施例３と実施例５、及び、実施例４と実施例６を比較すると、それぞれ、液晶パネルのバックライト側の吸収型直線偏光板がない実施例５、６の方が、高い輝度が得られた。 All of the mirror displays of Examples 3 to 6 showed a brightness improvement effect of 1.2 times or more as compared with the mirror display of Example 1. Moreover, when Example 3 and Example 5 and Example 4 and Example 6 are compared, the brightness | luminances of Example 5 and 6 without the absorption-type linear polarizing plate of the backlight side of a liquid crystal panel are respectively higher. was gotten.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
［付記］
本発明の一態様は、ハーフミラープレートと、上記ハーフミラープレートの背面側に配置された表示パネルとを備え、上記ハーフミラープレートは、第１の可視光反射コレステリック液晶層、及び、赤外光反射コレステリック液晶層を有するミラーディスプレイである。 [Appendix]
One embodiment of the present invention includes a half mirror plate and a display panel disposed on the back side of the half mirror plate, the half mirror plate including a first visible light reflecting cholesteric liquid crystal layer and infrared light. A mirror display having a reflective cholesteric liquid crystal layer.
本発明の一実施形態では、上記ハーフミラープレートは、更に、上記第１の可視光反射コレステリック液晶層と上記赤外光反射コレステリック液晶層とを接合する第１の粘着剤層を有する。 In one embodiment of the present invention, the half mirror plate further includes a first pressure-sensitive adhesive layer that joins the first visible light reflection cholesteric liquid crystal layer and the infrared light reflection cholesteric liquid crystal layer.
本発明の一実施形態では、上記ハーフミラープレートは、更に、透明基板を有する。 In one embodiment of the present invention, the half mirror plate further includes a transparent substrate.
本発明の一実施形態では、上記ハーフミラープレートは、更に、上記第１の可視光反射コレステリック液晶層又は上記赤外光反射コレステリック液晶層と上記透明基板とを接合する第２の粘着剤層を有する。 In one embodiment of the present invention, the half mirror plate further includes a second pressure-sensitive adhesive layer that joins the first visible light reflection cholesteric liquid crystal layer or the infrared light reflection cholesteric liquid crystal layer and the transparent substrate. Have.
本発明の一実施形態では、上記ハーフミラープレートは、上記第１の可視光反射コレステリック液晶層又は上記赤外光反射コレステリック液晶層と上記透明基板とが直に接する。 In one embodiment of the present invention, in the half mirror plate, the first visible light reflecting cholesteric liquid crystal layer or the infrared light reflecting cholesteric liquid crystal layer is in direct contact with the transparent substrate.
本発明の一実施形態では、上記表示パネルは、第１のλ／４板と、上記第１のλ／４板の背面側に配置された第１の直線偏光板とを有する。 In one embodiment of the present invention, the display panel includes a first λ / 4 plate and a first linearly polarizing plate disposed on the back side of the first λ / 4 plate.
本発明の一実施形態では、上記表示パネルは、上記第１の直線偏光板の背面側に配置された液晶層を有する。上記表示パネルは、更に、（１）上記液晶層の背面側に配置された反射型偏光板を有するものであってもよく、（２）上記液晶層の背面側に配置された第２のλ／４板と、上記第２のλ／４板の背面側に配置された第２の可視光反射コレステリック液晶層とを有するものであってもよく、（３）上記液晶層の背面側に配置された第２の直線偏光板を有するものであってもよい。 In one embodiment of the present invention, the display panel includes a liquid crystal layer disposed on the back side of the first linear polarizing plate. The display panel may further include (1) a reflective polarizing plate disposed on the back side of the liquid crystal layer, and (2) a second λ disposed on the back side of the liquid crystal layer. / 4 plate and a second visible light reflecting cholesteric liquid crystal layer disposed on the back side of the second λ / 4 plate, and (3) disposed on the back side of the liquid crystal layer. It may have a second linearly polarizing plate.
上記（３）の場合、上記表示パネルは、更に、（３－１）上記第２の直線偏光板の背面側に配置された第２のλ／４板と、上記第２のλ／４板の背面側に配置された第２の可視光反射コレステリック液晶層とを有するものであってもよく、（３－２）上記第２の直線偏光板の背面側に配置された反射型偏光板を有するものであってもよい。 In the case of (3), the display panel further includes (3-1) a second λ / 4 plate disposed on the back side of the second linearly polarizing plate, and the second λ / 4 plate. And a second visible light reflecting cholesteric liquid crystal layer disposed on the back side of the light source, and (3-2) a reflective polarizing plate disposed on the back side of the second linear polarizing plate. You may have.
本発明の一実施形態では、更に、上記表示パネルの背面側に配置されたバックライトを備える。 In one embodiment of the present invention, it further includes a backlight disposed on the back side of the display panel.
１０、１０ａ、１０ｂ：ハーフミラープレート
１１：透明基板（ガラス基板）
１３：可視光反射コレステリック液晶層
１３ａ：可視光反射コレステリック液晶フィルム
１３ｂ：可視光反射コレステリック液晶樹脂層
１５：赤外光反射コレステリック液晶層
１５ａ：赤外光反射コレステリック液晶フィルム
２０ａ、２０ｂ、２０ｃ、２０ｄ、２０ｅ：液晶パネル
２１：第１のλ／４板
２２：第１の吸収型直線偏光板
２３：カラーフィルタ基板
２４：液晶層
２５：ＴＦＴ基板
２６：第２の吸収型直線偏光板
２７：反射型直線偏光板
２８：第２のλ／４板
２９：第２の可視光反射コレステリック液晶フィルム
３０：バックライト
３１：発光ダイオード（ＬＥＤ）
６０ａ、６０ｂ、６０ｃ、６０ｄ、６０ｅ：ハーフミラープレート
６１：ガラス基板
６２：反射型直線偏光板
６３ａ：可視光反射コレステリック液晶フィルム
６３ｂ：可視光反射コレステリック液晶樹脂層
６４：λ／４板
７０ａ、７０ｂ：液晶パネル
７１：λ／４板
７２：吸収型直線偏光板
７３：λ／４板一体型円偏光板 10, 10a, 10b: Half mirror plate 11: Transparent substrate (glass substrate)
13: Visible light reflecting cholesteric liquid crystal layer 13a: Visible light reflecting cholesteric liquid crystal film 13b: Visible light reflecting cholesteric liquid crystal resin layer 15: Infrared light reflecting cholesteric liquid crystal layer 15a: Infrared light reflecting cholesteric liquid crystal films 20a, 20b, 20c, 20d 20e: liquid crystal panel 21: first λ / 4 plate 22: first absorption linear polarizing plate 23: color filter substrate 24: liquid crystal layer 25: TFT substrate 26: second absorption linear polarizing plate 27: reflection Type linear polarizing plate 28: second λ / 4 plate 29: second visible light reflecting cholesteric liquid crystal film 30: backlight 31: light emitting diode (LED)
60a, 60b, 60c, 60d, 60e: half mirror plate 61: glass substrate 62: reflective linear polarizing plate 63a: visible light reflecting cholesteric liquid crystal film 63b: visible light reflecting cholesteric liquid crystal resin layer 64: λ / 4 plates 70a, 70b : Liquid crystal panel 71: λ / 4 plate 72: Absorption type linearly polarizing plate 73: λ / 4 plate integrated type circularly polarizing plate

Claims (13)

  1. ハーフミラープレートと、
    前記ハーフミラープレートの背面側に配置された表示パネルとを備え、
    前記ハーフミラープレートは、第１の可視光反射コレステリック液晶層、及び、赤外光反射コレステリック液晶層を有する
    ことを特徴とするミラーディスプレイ。     Half mirror plate,
    A display panel disposed on the back side of the half mirror plate,
    The half mirror plate includes a first visible light reflecting cholesteric liquid crystal layer and an infrared light reflecting cholesteric liquid crystal layer.
  2. 前記ハーフミラープレートは、更に、前記第１の可視光反射コレステリック液晶層と前記赤外光反射コレステリック液晶層とを接合する第１の粘着剤層を有することを特徴とする請求項１に記載のミラーディスプレイ。 The said half mirror plate further has a 1st adhesive layer which joins the said 1st visible light reflection cholesteric liquid crystal layer and the said infrared light reflection cholesteric liquid crystal layer, The said 1st adhesive layer is characterized by the above-mentioned. Mirror display.
  3. 前記ハーフミラープレートは、更に、透明基板を有することを特徴とする請求項１又は２に記載のミラーディスプレイ。 The mirror display according to claim 1, wherein the half mirror plate further includes a transparent substrate.
  4. 前記ハーフミラープレートは、更に、前記第１の可視光反射コレステリック液晶層又は前記赤外光反射コレステリック液晶層と前記透明基板とを接合する第２の粘着剤層を有することを特徴とする請求項１～３のいずれかに記載のミラーディスプレイ。 The half mirror plate further includes a second pressure-sensitive adhesive layer that joins the first visible light reflecting cholesteric liquid crystal layer or the infrared light reflecting cholesteric liquid crystal layer and the transparent substrate. The mirror display according to any one of 1 to 3.
  5. 前記ハーフミラープレートは、前記第１の可視光反射コレステリック液晶層又は前記赤外光反射コレステリック液晶層と前記透明基板とが直に接することを特徴とする請求項１～３のいずれかに記載のミラーディスプレイ。 4. The half mirror plate according to claim 1, wherein the first visible light reflection cholesteric liquid crystal layer or the infrared light reflection cholesteric liquid crystal layer and the transparent substrate are in direct contact with each other. Mirror display.
  6. 前記表示パネルは、第１のλ／４板と、前記第１のλ／４板の背面側に配置された第１の直線偏光板とを有することを特徴とする請求項１～５のいずれかに記載のミラーディスプレイ。 6. The display panel according to claim 1, wherein the display panel includes a first λ / 4 plate and a first linearly polarizing plate disposed on the back side of the first λ / 4 plate. Mirror display according to crab.
  7. 前記表示パネルは、前記第１の直線偏光板の背面側に配置された液晶層を有することを特徴とする請求項６に記載のミラーディスプレイ。 The mirror display according to claim 6, wherein the display panel includes a liquid crystal layer disposed on a back side of the first linear polarizing plate.
  8. 前記表示パネルは、更に、前記液晶層の背面側に配置された反射型偏光板を有することを特徴とする請求項７に記載のミラーディスプレイ。 The mirror display according to claim 7, wherein the display panel further includes a reflective polarizing plate disposed on a back side of the liquid crystal layer.
  9. 前記表示パネルは、更に、前記液晶層の背面側に配置された第２のλ／４板と、前記第２のλ／４板の背面側に配置された第２の可視光反射コレステリック液晶層とを有することを特徴とする請求項７に記載のミラーディスプレイ。 The display panel further includes a second λ / 4 plate disposed on the back side of the liquid crystal layer, and a second visible light reflecting cholesteric liquid crystal layer disposed on the back side of the second λ / 4 plate. The mirror display according to claim 7, further comprising:
  10. 前記表示パネルは、更に、前記液晶層の背面側に配置された第２の直線偏光板を有することを特徴とする請求項７に記載のミラーディスプレイ。 The mirror display according to claim 7, wherein the display panel further includes a second linear polarizing plate disposed on a back side of the liquid crystal layer.
  11. 前記表示パネルは、更に、前記第２の直線偏光板の背面側に配置された第２のλ／４板と、前記第２のλ／４板の背面側に配置された第２の可視光反射コレステリック液晶層とを有することを特徴とする請求項１０に記載のミラーディスプレイ。 The display panel further includes a second λ / 4 plate disposed on the back side of the second linearly polarizing plate, and a second visible light disposed on the back side of the second λ / 4 plate. The mirror display according to claim 10, further comprising a reflective cholesteric liquid crystal layer.
  12. 前記表示パネルは、更に、前記第２の直線偏光板の背面側に配置された反射型偏光板を有することを特徴とする請求項１０に記載のミラーディスプレイ。 The mirror display according to claim 10, wherein the display panel further includes a reflective polarizing plate disposed on a back side of the second linear polarizing plate.
  13. 更に、前記表示パネルの背面側に配置されたバックライトを備えることを特徴とする請求項１～１２のいずれかに記載のミラーディスプレイ。 The mirror display according to any one of claims 1 to 12, further comprising a backlight disposed on the back side of the display panel.
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