WO2017038242A1 - Optical device, display device and electronic device - Google Patents

Optical device, display device and electronic device Download PDF

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Publication number
WO2017038242A1
WO2017038242A1 PCT/JP2016/069926 JP2016069926W WO2017038242A1 WO 2017038242 A1 WO2017038242 A1 WO 2017038242A1 JP 2016069926 W JP2016069926 W JP 2016069926W WO 2017038242 A1 WO2017038242 A1 WO 2017038242A1
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WIPO (PCT)
Prior art keywords
liquid crystal
linearly polarized
polarized light
display
mode
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PCT/JP2016/069926
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French (fr)
Japanese (ja)
Inventor
涼 小川
一昭 亀島
谷野　友哉
祐治 中畑
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ソニー株式会社
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Publication of WO2017038242A1 publication Critical patent/WO2017038242A1/en

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    • 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
    • G02F1/1347—Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
    • 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 disclosure relates to an optical device that switches between a transmissive state that transmits light and a mirror surface state that reflects light, and a display device and an electronic apparatus including the optical device.
  • a display device configured to be able to switch between a normal screen state (image display mode or external light transmission mode) and a specular state (external light reflection mode) by overlapping two liquid crystal panels (for example, see Patent Documents 1 and 2).
  • a display device is, for example, a display in which a reflective polarizing plate, a liquid crystal panel, and an absorbing polarizing plate are stacked in order from the liquid crystal display unit to the viewer on the viewer side of the liquid crystal display unit.
  • a switching unit is provided.
  • the image display mode external light transmission mode
  • the external light reflection mode the light sequentially transmitted through the liquid crystal panel and the absorption polarizing plate in the display switching unit is visually recognized.
  • the image light visually recognized by the observer is affected by the transmission characteristics of the liquid crystal panel and the absorption polarizing plate, and is caused by, for example, the wavelength dispersion of the absorption polarizing plate and the wavelength dispersion of the liquid crystal panel. Coloring may occur and display quality may be lost.
  • An optical device transmits a first linearly polarized light having a first polarization axis and reflects a second linearly polarized light having a second polarization axis that intersects the first polarization axis.
  • a liquid crystal panel having a reflective polarizing member, a TN (Twisted ⁇ Nematic) liquid crystal layer containing liquid crystal molecules aligned along the first polarization axis, and a pair of transparent electrodes facing each other with the TN liquid crystal layer interposed therebetween And a transmissive polarizing member that absorbs the first linearly polarized light and transmits the second linearly polarized light in order.
  • the liquid crystal molecules in the TN liquid crystal layer are aligned along the first polarization axis. Therefore, in the light transmission mode, the absorptive polarizing member disposed immediately before the light transmission mode. When the first linearly polarized light that transmits through the TN liquid crystal layer is transmitted, excellent viewing angle characteristics can be obtained.
  • a display device includes a display unit that emits first linearly polarized light having a first polarization axis as image light, and is disposed to face the display unit.
  • a display switching unit that switches between an image display mode that transmits light and an external light reflection mode that reflects external light;
  • the display unit includes a first absorptive polarizing member that transmits the first linearly polarized light and absorbs the second linearly polarized light having the second polarization axis that intersects the first polarization axis.
  • the switching unit includes a second absorptive polarizing member that transmits the first linearly polarized light and absorbs the second linearly polarized light, a TN-type liquid crystal layer that includes liquid crystal molecules aligned along the first polarization axis, and A liquid crystal panel having a pair of transparent electrodes facing each other with the TN liquid crystal layer interposed therebetween, and a reflective polarizing member that transmits the first linearly polarized light and reflects the second linearly polarized light, in a direction approaching the display unit In order.
  • An electronic apparatus as an embodiment of the present disclosure includes the display device as an embodiment of the present disclosure and a control unit that controls the display device.
  • the display switching unit switches between the image display mode and the external light reflection mode.
  • the liquid crystal molecules in the TN type liquid crystal layer are aligned along the first polarization axis, in the image display mode, the first linearly polarized light that passes through the absorption polarizing member disposed immediately before the liquid crystal molecule is When transmitting through the TN type liquid crystal layer, excellent viewing angle characteristics are obtained.
  • the optical device as one embodiment of the present disclosure, it is possible to exhibit excellent visibility of transmitted light in the external light transmission mode and excellent visibility of reflected light in the external light reflection mode.
  • the display device and the electronic apparatus as an embodiment of the present disclosure, it is possible to exhibit excellent display performance in both the image display mode and the external light reflection mode.
  • FIG. 5 is a characteristic diagram illustrating a polarization state at the time of emission when an incident angle of each light of red, green, and blue is changed in an O-mode TN liquid crystal.
  • FIG. 6 is a characteristic diagram illustrating a polarization state at the time of emission when an incident angle of each of red, green, and blue light is changed in an E-mode TN liquid crystal. It is a characteristic view showing the change of the polarization state in the O-mode TN type liquid crystal layer of the light incident at a polar angle of 60 ° and an azimuth of 45 °.
  • FIG. 10 is a characteristic diagram illustrating viewing angle characteristics of chromaticity and luminance in a transmission state in Experimental Example 1-1.
  • FIG. 10 is a characteristic diagram illustrating viewing angle characteristics of chromaticity and luminance in a mirror state in Experimental Example 1-1.
  • FIG. 10 is a characteristic diagram illustrating viewing angle characteristics of chromaticity and luminance in a mirror state in Experimental Example 1-1.
  • FIG. 10 is a characteristic diagram illustrating viewing angle characteristics of chromaticity and luminance in a transmission state in Experimental Example 1-2.
  • FIG. 10 is a characteristic diagram illustrating viewing angle characteristics of chromaticity and luminance in a mirror state in Experimental Example 1-2. It is a characteristic diagram showing the viewing angle dependence of chromaticity at 0 ° azimuth in Experimental Examples 2-1 and 2-2.
  • FIG. 11 is a characteristic diagram showing viewing angle dependence of chromaticity at 45 ° azimuth in Experimental Examples 2-1 and 2-2. It is a characteristic view showing the relationship between the applied voltage with respect to the display switching part in Example 3 of an experiment, and a reflectance.
  • FIG. 1 illustrates an overall configuration including a cross section of a display device 1 as an embodiment of the present disclosure.
  • FIG. 2 is a conceptual diagram showing the operation of the display device 1.
  • the display device 1 is configured such that a screen state and a mirror surface state can be switched by overlapping two liquid crystal panels.
  • the display device 1 includes a display unit 10 and a display switching unit 20 that are arranged to face each other so that their main surfaces overlap each other.
  • the display unit 10 emits image light forming a predetermined display mode toward an observer, and the display switching unit 20 is disposed on the viewer side of the display unit 10 and transmits image light from the display unit 10.
  • the display device 1 further includes a switching drive unit 30 and a control unit 40, and the switching drive unit 30 performs a switching operation in the display switching unit 20 according to a command from the control unit 40.
  • the switching drive unit 30 drives the liquid crystal panel 22 provided in the display switching unit 20.
  • the switching drive unit 30 controls the applied voltage supplied to the liquid crystal panel 22, and determines whether or not to apply a voltage equal to or higher than the threshold voltage between a pair of opposing transparent electrodes of the liquid crystal panel 22, for example. It is.
  • the display part 10 and the display switching part 20 should just overlap at least one part mutually.
  • Display unit 10 In the present embodiment, a case where a liquid crystal display element is used as the display unit 10 will be described. However, in the present technology, various display mechanisms such as an electroluminescence element, a plasma display panel, or electronic paper can be applied as the display unit 10.
  • the driving mode of the display unit 10 includes an active driving mode such as active matrix driving using active elements such as TFT (Thin Film Transistor) and TFD (Thin Film Film Diode), and simple driving without using the active elements as described above. Or any of passive drive modes, such as a multiplex drive, may be sufficient.
  • the panel structure of the display unit 10 may be any of a transmissive panel, a reflective panel, and a reflective transflective panel. In this embodiment, the case where a transmissive panel is used will be described.
  • the display unit 10 includes an absorption polarizing plate 11, a liquid crystal panel 13, an absorption polarizing plate 14, and a backlight 15 in order from a position close to the display switching unit 20.
  • a retardation plate may be further disposed between the absorption polarizing plate 11 and the liquid crystal panel 13.
  • the liquid crystal panel 13 has a structure in which a liquid crystal layer 13C is sandwiched between a transparent electrode substrate 13A and a substrate 13B.
  • the transparent electrode substrate 13A and the transparent electrode substrate 13B are obtained by forming a transparent conductive layer on a transparent substrate such as glass (including quartz) and facing each other so as to have a predetermined interval (for example, about 1.5 ⁇ m to 10 ⁇ m). It arrange
  • liquid crystal mode in the liquid crystal layer 13C of the liquid crystal panel 13 examples include a TN (Twisted Nematic) mode, a VA (Vertical Alignment) mode, an IPS (In Plane Switching) mode, an FFS (Fringe Field Switching) mode, and an STN (Super Twisted Nematic). Mode, or ECB (Electrically Controlled Birefringence) mode can be used. Since the liquid crystal display element having these liquid crystal modes is configured to realize a display mode using a polarizing plate, it is preferable because a high display quality can be obtained with a relatively low driving voltage. Of these, the VA mode is particularly preferable.
  • the VA mode liquid crystal display element is less likely to float black when stress is applied to the absorption polarizing plates 11 and 14 of the display unit 10 as compared with other liquid crystal modes (for example, IPS mode).
  • black floating means that light leaks in part during black display.
  • the display unit 10 and the display switching unit 20 are bonded together by, for example, a third resin layer 33 (hereinafter simply referred to as a resin layer 33).
  • a gel-like resin is cured and contracted to form the resin layer 33. As the resin is cured and contracted, the polarization of the display unit 10 is increased.
  • the plate particularly the absorption-type polarizing plate 11.
  • black floating may occur slightly in the corners of the display area.
  • VA mode liquid crystal display element As the display unit 10, Black float can be suppressed.
  • the display part 10 (absorption type polarizing plate 11) and the display switch part 20 (reflective type polarizing plate 21 mentioned later) are bonded together through the resin layer 33, the absorption type polarizing plate 11 by bonding and Generation of irregularities in the vicinity of the interface with the reflective polarizing plate 21 can be suppressed.
  • the resin layer 33 for example, a highly transparent substrate-less tape CTL-NC103 manufactured by Lintec, or a double-sided adhesive tape for substrate-less optics DAITAC ZB7010W-10 manufactured by DIC can be used.
  • the absorptive polarizing plates 11 and 14 are set in a required arrangement (for example, a crossed Nicol arrangement) in the configuration of the liquid crystal device 1.
  • the absorptive polarizing plates 11 and 14 have transmission polarization axes 11J and 14J, respectively, transmit linearly polarized light having vibration planes parallel to the transmission polarization axes 11J and 14J, and cross the transmission polarization axes 11J and 14J ( It absorbs linearly polarized light having a vibration plane parallel to the (preferably orthogonal) direction.
  • the absorption polarizing plates 11 and 14 for example, a film obtained by applying a protective layer of triacetyl cellulose on both surfaces of a film imparted with a polarizing function by absorbing iodine into stretched polyvinyl alcohol can be used.
  • the backlight 15 only needs to be able to illuminate the liquid crystal panel 13 with substantially uniform illuminance from behind.
  • an edge-emitting backlight including a light guide plate and a light source disposed on an end surface portion of the light guide plate, or a back-emitting backlight including a light guide plate and a light source disposed on the back surface of the light guide plate Light etc. are mentioned.
  • the display switching unit 20 includes a reflective polarizing plate 21, a liquid crystal panel 22, and an absorption polarizing plate 23 arranged in this order from the display unit 10 toward the viewer.
  • a viewing angle improving film may be disposed between at least one of the absorption type polarizing plate 23 and the liquid crystal panel 22 and between at least one of the reflection type polarizing plate 21 and the liquid crystal panel 22.
  • the reflective polarizing plate 21 has a transmission polarization axis 21J.
  • the reflective polarizing plate 21 transmits linearly polarized light having a vibration plane parallel to the transmission polarization axis 21J, while linearly polarized light having a vibration plane parallel to the direction intersecting (preferably orthogonal to) the transmission polarization axis 21J. It is a reflection.
  • the reflection-type polarizing plate 21 transmits the first linearly polarized light Lp (described later) emitted from the display unit 10 and the second linearly polarized light Ls (rear) having a transmission polarization axis perpendicular thereto. Out) has the function of specular reflection.
  • a birefringence reflective polarizing film in which a plurality of different birefringent polymer films disclosed in International Publication No. WO95 / 27919 is alternately laminated, or a cholesteric liquid crystal layer is used.
  • positioned to the front and back of this can be used.
  • birefringent reflective polarizing film used as the reflective polarizing plate 21 examples include those commercially available from 3M (USA) under the trade name DBEF.
  • DBEF trade name for birefringent reflective polarizing film.
  • Such a birefringent reflective polarizing film has a function of transmitting predetermined linearly polarized light and specularly reflecting linearly polarized light having a polarization axis orthogonal to the polarization axis of the linearly polarized light.
  • the reflective polarizing plate 21 is composed of a cholesteric liquid crystal layer with a quarter-wave plate disposed on the front and back, a liquid crystal containing a low-molecular cholesteric liquid crystal between two aligned transparent substrates.
  • a cell or a polymer cholesteric liquid crystal layer formed on a flat and optically isotropic transparent substrate such as glass or transparent resin can be used.
  • the cholesteric liquid crystal layer exhibits unique optical characteristics based on a helical molecular arrangement. Light incident in parallel to the helical axis reflects circularly polarized light in one rotational direction according to the rotational direction of the cholesteric helix, The other shows selective reflection of transmitting.
  • the wavelength range of selective reflection is determined by the pitch of the molecular arrangement, it is necessary to stack and use a plurality of cholesteric liquid crystal layers having different pitches in order to cause selective reflection over the entire visible wavelength range.
  • Asia ⁇ ⁇ Display 95 Digest, p735, The Institute Television Engineers of Japan (ITE) & The Society for Information Display A cholesteric liquid crystal layer whose pitch is continuously changed as described in (SID) IV may be used.
  • a quarter wavelength plate disposed on the back side of the cholesteric liquid crystal layer that is, on the display unit 10 side.
  • the slow axis may be set in the following direction. That is, the slow axis is arranged so that the first linearly polarized light Lp emitted from the display unit 10 and incident on the reflective polarizing plate 21 is converted into circularly polarized light that passes through the cholesteric liquid crystal layer.
  • the quarter-wave plate similarly disposed on the front side of the cholesteric liquid crystal layer that is, on the liquid crystal panel 22 side, has a slow phase so that the circularly polarized light transmitted through the cholesteric liquid crystal layer is converted into the first linearly polarized light Lp. Arrange the axes.
  • the second linearly polarized light Ls is incident on the reflective polarizing plate 21 having the structure in which the quarter wavelength plates are arranged on the front and back of the cholesteric liquid crystal layer in this way, the second linearly polarized light Ls is 1/4.
  • the wave plate By the action of the wave plate, it is converted into circularly polarized light that is opposite to the circularly polarized light that passes through the cholesteric liquid crystal layer. Therefore, the second linearly polarized light Ls is selectively reflected by the cholesteric liquid crystal layer.
  • the circularly polarized light reflected by the cholesteric liquid crystal layer passes through the quarter wavelength plate again, it is converted into the second linearly polarized light Ls by the action of the quarter wavelength plate.
  • the quarter wavelength plate used for the reflection type polarizing plate 21 of this structure it is desirable to use what functions as a quarter wavelength plate in the whole visible wavelength range.
  • a stretched polymer film having a high transmittance in the visible wavelength region such as polyvinyl alcohol, polycarbonate, polysulfone, polystyrene, polyarylate, or the like can be used.
  • mica, quartz, a liquid crystal layer with molecular axes aligned in one direction, and the like can be used.
  • wavelength dispersion due to the wavelength dependence of the refractive index of the material constituting the quarter wavelength plate (hereinafter referred to as wavelength dispersion), one type of retardation plate functions as a quarter wavelength plate for the entire visible wavelength range. It is difficult to construct a plate. However, what is necessary is just to use what was comprised so that it might function as a quarter wavelength plate in a wide wavelength range by bonding together at least 2 types of phase contrast plates from which wavelength dispersion differs so that the optical axis may intersect perpendicularly.
  • the reflective polarizing plate 21 and the liquid crystal panel 22 may be bonded together via a first resin layer 31 (hereinafter simply referred to as a resin layer 31) having a thickness of, for example, 25 ⁇ m or less.
  • a resin layer 31 having a thickness of, for example, 25 ⁇ m or less.
  • the absorption polarizing plate 23 has a transmission polarization axis 23J.
  • the absorptive polarizing plate 23 transmits linearly polarized light having a vibration plane parallel to the transmission polarization axis 23J, while linearly polarized light having a vibration plane parallel to a direction intersecting (preferably orthogonal) to the transmission polarization axis 23J.
  • the absorption polarizing plate 23 has a function of absorbing the first linearly polarized light Lp and transmitting the second linearly polarized light Ls orthogonal thereto.
  • the liquid crystal panel 22 sandwiched between the reflection-type polarizing plate 21 and the absorption-type polarizing plate 23 converts the first linearly polarized light Lp into a second linearly polarized light Ls having a polarization axis perpendicular to the first linearly polarized light Lp and transmits the converted light. Switching between the first mode and the second mode in which the first linearly polarized light Lp is transmitted as it is without being converted into the second linearly polarized light Ls is performed.
  • the liquid crystal panel 22 has a structure in which a liquid crystal layer 22C is sandwiched between a transparent electrode substrate 22A and a transparent electrode substrate 22B so that a predetermined electric field can be applied to the liquid crystal layer 22C.
  • the transparent electrode substrate 22A and the transparent electrode substrate 22B are formed by forming a transparent conductive layer such as ITO on a transparent substrate such as glass (including quartz), and are connected to the driving unit 30 and controlled by the control unit 40. Thus, a voltage is applied.
  • the transparent electrode substrate 22A and the transparent electrode substrate 22B are opposed to each other so as to have a predetermined interval (for example, about 1.5 ⁇ m to 10 ⁇ m), and are bonded together by a seal material (not shown).
  • the liquid crystal layer 22C is a TN (Twisted Nematic) type liquid crystal layer including liquid crystal molecules aligned along the transmission polarization axis 23J. Therefore, the display mode of the liquid crystal panel 22 is the TN mode. That is, the liquid crystal layer 22C has an alignment axis 22J that is substantially parallel to the transmission polarization axis 23J.
  • the liquid crystal molecules in the liquid crystal layer 22C may have a pretilt angle of 5 ° or less.
  • the liquid crystal panel 22 and the absorption polarizing plate 23 may be bonded together via a second resin layer 32 (hereinafter simply referred to as a resin layer 32) having a thickness of, for example, 25 ⁇ m or less.
  • a resin layer 32 having a thickness of, for example, 25 ⁇ m or less.
  • a resin layer 32 for example, a highly transparent substrate-less tape CTL-NC103 manufactured by Lintec, a double-sided adhesive tape for substrate-less optical DAITAC ZB7010W-10 or DAITAC ZB7011W manufactured by DIC, etc. can be used. .
  • a retardation plate (not shown) may be disposed between the liquid crystal panel 22 and the absorption polarizing plate 23 and between the liquid crystal panel 22 and the reflection polarizing plate 21.
  • the transmission polarization axis 21J of the reflection-type polarization plate 21 and the transmission polarization axis 11J of the absorption-type polarization plate 11 are substantially parallel, or It is preferable that the transmission polarization axis 21 ⁇ / b> J and the transmission polarization axis 11 ⁇ / b> J of the absorptive polarizing plate 11 are arranged so as to be substantially orthogonal to each other. In the display device 1, it is desirable that the transmission polarization axis of the absorption polarizing plate 11 and the transmission polarization axis of the absorption polarizing plate 14 are substantially orthogonal to each other.
  • the transmission polarization axis 21J of the reflection-type polarization plate 21 and the transmission polarization of the absorption-type polarization plate 14 may be substantially orthogonal.
  • the transmission polarization axis 21J of the reflection-type polarizing plate 21 and the transmission polarization axis 11J of the absorption-type polarization plate 11 are substantially orthogonal
  • the transmission polarization axis 21J of the reflection-type polarization plate 21 and the absorption-type polarization plate 14 is preferably substantially parallel to the transmission polarization axis 14J.
  • an active drive mode such as an active matrix drive using active elements such as TFT and TFD, and a simple drive without using the active elements as described above.
  • any of passive drive modes such as a multiplex drive, may be sufficient.
  • the control unit 40 performs switching between the image display mode and the external light reflection mode in the liquid crystal panel 22 by applying a DC voltage between the transparent electrode substrate 22A and the transparent electrode substrate 22B, or It is good to carry out by applying an alternating voltage of 10 Hz (hertz) or less between the transparent electrode substrate 22A and the transparent electrode substrate 22B. This is because it is advantageous for further reducing the power consumption required for the switching operation between the image display mode and the external light reflection mode in the liquid crystal panel 22 of the display switching unit 20.
  • the liquid crystal layer 22C may have a retardation value ( ⁇ n ⁇ d) of 0.36 ⁇ m or more and less than 0.54 ⁇ m. This is because, when ⁇ n ⁇ d of the liquid crystal layer 22C is within the above-described range, coloring of the display image formed by the display unit 10 can be reduced and the display image can be brightened. In addition, since the retardation value is small, bleeding of the display image is reduced, and a certain wide viewing angle can be secured.
  • ⁇ n at a wavelength of 550 nm of the liquid crystal layer 22C is preferably 0.09 or more and less than 0.14. This is because the transmission characteristics in the mirror state (external light reflection mode), particularly the transmission characteristics in the wavelength range of 400 nm to 500 nm, are improved.
  • the display switching unit 20 is in a transmissive state (by controlling the strength of the electric field applied to the liquid crystal layer 22 ⁇ / b> C of the liquid crystal panel 22 in the display switching unit 20 or switching the presence / absence of application of the electric field. Screen state), and the display switching unit 20 can be in a mirror state.
  • the liquid crystal panel 22 of the display switching unit 20 is a TN liquid crystal panel, and is arranged so that the transmission polarization axis of the reflective polarizing plate 21 and the transmission polarization axis of the absorption polarizing plate 23 are substantially parallel. The behavior of the case will be described with reference to FIG. 1 and FIG.
  • the nematic liquid crystal included in the liquid crystal layer 22C is in a twisted state of 90 degrees, and basically has a first mode of optical rotation of 90 degrees. It becomes.
  • the external light L1 incident on the display switching unit 20 passes through the absorption-type polarizing plate 23 and thereby has a second straight line having a vibration plane parallel to the transmission polarization axis 23J of the absorption-type polarizing plate 23. The polarization becomes Ls.
  • the second linearly polarized light Ls is then converted to the first linearly polarized light Lp having a vibration plane parallel to the transmission polarization axis 23J of the absorption polarizing plate 23 by passing through the liquid crystal panel 22.
  • the first linearly polarized light Lp then passes through the reflective polarizing plate 21, the absorbing polarizing plate 11, and the liquid crystal panel 13 as they are, and enters the absorbing polarizing plate 14. Since the first linearly polarized light Lp has a vibration plane orthogonal to the transmission polarization axis 14J of the absorption polarizing plate 14, it is absorbed by the absorption polarizing plate 14.
  • the light L2 emitted from the display unit 10 (that is, the image light constituting the display image of the display unit 10) is a first linearly polarized light having a vibration plane parallel to the transmission polarization axis 11J by the absorption polarizing plate 11.
  • Lp The first linearly polarized light Lp passes through the reflective polarizing plate 21 and enters the liquid crystal panel 22.
  • the vibration plane of the first linearly polarized light Lp incident on the liquid crystal panel 22 is rotated by 90 degrees by passing through the liquid crystal panel 22, and is a second straight line having a vibration plane parallel to the transmission polarization axis 23J of the absorption polarizing plate 23.
  • the polarization becomes Ls.
  • the second linearly polarized light Ls passes through the absorption polarizing plate 23 as it is and is visually recognized by the observer (screen state).
  • the external light L1 is absorbed by the absorption polarizing plate 14 after passing through the display switching unit 20 without being reflected toward the viewer,
  • the image light L2 from the display unit 10 is in a state visible from the outside. That is, the display screen of the display device 1 is in a screen state (image display mode).
  • the second linearly polarized light Ls passes through the liquid crystal panel 22 as it is without being converted into the first linearly polarized light Lp and then enters the reflective polarizing plate 21. Since the second linearly polarized light Ls has a vibration surface in a direction perpendicular to the transmission polarization axis 21J of the reflective polarizing plate 21, it is reflected by the reflective polarizing plate 21. The reflected second linearly polarized light Ls passes through the liquid crystal panel 22 and the absorptive polarizing plate 23 in order again and is visually recognized by the observer.
  • the image light L2 emitted from the display unit 10 is the first linearly polarized light Lp having a vibration plane parallel to the transmission polarization axis 11J of the absorption polarizing plate 11, and thus passes through the reflection polarizing plate 21 as it is. Incident on the liquid crystal panel 22.
  • the first linearly polarized light Lp passes through the liquid crystal panel 22 as it is and then enters the absorption polarizing plate 23. Since the first linearly polarized light Lp has a vibration plane orthogonal to the transmission polarization axis 23J, it is absorbed by the absorptive polarizing plate 23. For this reason, the image light emitted from the display unit 10 is not visually recognized from the outside.
  • the image light L2 from the display unit 10 cannot be visually recognized from the outside, and the external light L1 is reflected toward the observer.
  • the screen is in a mirror state (external light reflection mode).
  • the display switching unit 20 sets the reflective polarizing plate 21 and the absorbing polarizing plate 23 in a crossed Nicols arrangement, and the TN type liquid crystal in the liquid crystal panel 22 is so-called E. Since it is used in -mode (Extraordinary-mode), excellent viewing angle characteristics regarding luminance and chromaticity can be obtained.
  • E-mode is a mode in which the long axis direction of liquid crystal molecules, that is, an abnormal light component is used.
  • TN type liquid crystal is used in O-mode (Ordinary-mode) in a display unit (liquid crystal monitor or the like).
  • O-mode is an abbreviation for Ordinary-mode, which is a mode using the short axis direction of liquid crystal molecules, that is, an ordinary light component.
  • E-mode is better for luminance characteristics and contrast viewing angle characteristics when no voltage is applied.
  • the luminance characteristics and the contrast viewing angle characteristics during voltage application are better in O-mode.
  • gradation inversion is likely to occur, and it is necessary to emphasize the viewing angle of black to halftone. Therefore, TN type liquid crystal used in the display section has a wide range of O-mode with good black to halftone characteristics. It is thought that it is used.
  • the TN liquid crystal is used for the liquid crystal panel 22 in the display switching unit 20 that switches between the image display mode (external light transmission mode) and the external light reflection mode
  • the viewing angle characteristics related to brightness and chromaticity in the specular state (external light reflection mode) are equivalent, and the brightness and chromaticity in the screen state (external light transmission mode). This is because the viewing angle characteristics are improved.
  • the Poincare sphere is one of the representation methods that can visually represent the polarization state, and the polarization state can be understood by the point on the sphere.
  • the equator represents linearly polarized light
  • the longitude indicates the direction.
  • Latitude expresses ellipticity and is circularly polarized in the north and south poles.
  • 3A and 3B show the output when the incident angles (polar angles) of red, green, and blue light (wavelengths of 450 nm, 550 nm, and 650 nm) are changed for each of O-mode and E-mode. It shows the polarization state at the time.
  • the polar angle is changed from 0 ° to 80 °, the direction in which each light is incident is 45 °, and it is cut out into the S1-S2 plane for consideration.
  • O-mode is more angularly dependent on the change in polarization state than the E-mode.
  • O-mode is more wavelength-dependent than E-mode, and it can be said that coloring is increased when viewed from an oblique direction.
  • the effective incident polarization axis is a polarization axis shifted by an angle ( ⁇ ) when the polarizing plate is viewed obliquely. It can also be seen that the displacement amount of the vertical axis (S3) is larger in O-mode than in E-mode. Since the S3 axis represents the change in ellipticity, it indicates that there is a difference in the sensitivity of the phase difference.
  • FIGS. 5A and 5B schematically show the relationship between the liquid crystal alignment axis in the TN liquid crystal and the transmission axis of the polarizing plate for each of O-mode and E-mode.
  • E-mode since the effective transmission axis of the polarizing plate and the slow axis of the liquid crystal molecules always coincide with each other, a phase difference hardly occurs.
  • the slow axis of the liquid crystal molecules is 90 ° + ⁇ . This means that the fact that the polarization axis and the slow axis are displaced by ⁇ means that a phase difference is more likely to occur.
  • the amount of change in ellipticity every time it passes through each layer of the liquid crystal is increased, and as a result, the wavelength dependency is also increased, and it is considered that coloring is facilitated.
  • E-mode is preferable as the TN liquid crystal used in the liquid crystal panel 22 for switching between the image display mode (external light transmission mode) and the external light reflection mode.
  • the control unit 40 when the switching operation between the image display mode and the external light reflection mode in the liquid crystal panel 22 is performed, the control unit 40 applies the DC voltage applied between the transparent electrode substrate 22A and the transparent electrode substrate 22B. Or it is good to control the switching drive part 30 so that the increase / decrease speed of an alternating voltage may be changed. This is because an operation delay due to the resistance of the transparent electrode substrates 22A and 22B (operational deviation due to the position in the screen) can be reduced.
  • FIG. 6A is a characteristic diagram showing a change in voltage applied between the transparent electrode substrate 22A and the transparent electrode substrate 22B. In FIG.
  • a solid line graph indicates a voltage change at a position P1 in the vicinity of the connection portion between the transparent electrode substrates 22A and 22B and the wiring from the switching drive unit 30 (for example, near the left end of the transparent electrode substrates 22A and 22B in FIG. 1).
  • the broken line graph indicates a position P2 in the vicinity of the end opposite to the connection portion between the transparent electrode substrates 22A and 22B and the wiring from the switching drive unit 30 (for example, near the right end of the transparent electrode substrates 22A and 22B in FIG. This represents the voltage change at.
  • the voltage increase and decrease are each performed at a constant rate.
  • the voltage increase and decrease may be performed step by step (multiple steps). Good.
  • FIGS. 7A and 7B when the voltage change waveform is rectangular, that is, a DC voltage or an AC voltage applied between the transparent electrode substrate 22A and the transparent electrode substrate 22B. Is instantaneously changed, the voltage change at the position P2 (broken line graph) is relatively delayed with respect to the voltage change at the position P1 (solid line graph).
  • FIG. 7A illustrates the case where voltage application of one step is performed until reaching a predetermined voltage required for the switching operation between the image display mode and the external light reflection mode
  • FIG. 7B illustrates the image display mode and the external light reflection. A case where voltage application in two steps is performed until reaching a predetermined voltage required for the mode switching operation is illustrated.
  • the liquid crystal layer 22C of the liquid crystal panel 22 has ⁇ n ⁇ d of 0.36 ⁇ m or more and less than 0.54 ⁇ m, the colored display image formed by the display unit 10 is colored. Can be reduced, and the display image can be brightened. In addition, the blur of the display image is reduced, and a wide viewing angle can be secured to some extent.
  • ⁇ n at a wavelength of 550 nm of the liquid crystal layer 22C is set to 0.09 or more and less than 0.14, it is possible to improve the transmission characteristics in the mirror surface state, particularly the transmission characteristics in the wavelength range of 400 nm to 500 nm.
  • FIG. 8 is a schematic diagram illustrating the overall configuration of the electronic device 100.
  • the electronic device 100 includes the display device 1 according to the first embodiment.
  • FIG. 8 is a block diagram schematically showing a display control system of the display device 100 arranged inside the electronic device 100.
  • the electronic device 100 includes a display drive unit 13X and an illumination drive unit 15X.
  • the control unit 40 controls the switching drive unit 30 that drives the switching unit 20, and also controls the display drive unit 13X and the illumination drive unit 15X.
  • Each of the above components may be installed inside the display device 1, or may be installed outside the display device 1, that is, in an area other than the display device 1 inside the electronic device 100, Alternatively, some components may be installed inside the display device 1, and other components may be installed inside the electronic device 100 other than the display device 1.
  • the display driving unit 13X drives the liquid crystal panel 13 provided in the display unit 10 of the display device 1.
  • the display drive unit 13X supplies drive voltages for driving a plurality of pixel regions configured in the liquid crystal drive region of the liquid crystal panel 13, and for example, in the multiplex drive method and the active drive method, scanning is performed.
  • a signal and a data signal corresponding to the scanning signal are supplied in synchronization with the common terminal (scanning line terminal) and the segment terminal (data line terminal) of the liquid crystal panel 13, respectively.
  • Display data such as image data is sent from the main circuit of the electronic device 100 to the display driving unit 13X via the control unit 100X.
  • the illumination driving unit 15X drives the backlight 15 of the display unit 10. More specifically, the illumination drive unit 15X functions to control power supply to the backlight 15 and to switch between a lighting state and a light-off state of the backlight 15, for example.
  • the control unit 40 controls the display driving unit 13X, the illumination driving unit 15X, and the switching driving unit 30, respectively, and performs control commands and data transmission to the respective units.
  • the display driving unit 13X drives the liquid crystal panel 13 to display an image
  • the switching driving unit 30 performs the liquid crystal panel display.
  • the display switching unit 20 is brought into a transmissive state.
  • the display switching unit 20 is set to the external light reflection mode and the display device 1 is set to the mirror state
  • the display switching unit 20 is set to the external light reflection mode by controlling the liquid crystal panel 22 by the switching drive unit 30.
  • the liquid crystal panel 13 is brought into a completely blocked state (shutter closed state) by the display driving unit 13X, or the backlight 15 is turned off by the illumination driving unit 15X.
  • the display device 1 since the display device 1 is provided, it is possible to improve the viewing angle characteristics in the display image and the reflected image visually recognized by the observer. For this reason, according to the electronic device 100, excellent display performance can be exhibited both in the screen state (image display mode) and in the mirror surface state (external light reflection mode).
  • Examples of the electronic device 100 include a television device, a digital camera, a notebook personal computer, a mobile terminal device such as a mobile phone, a smartphone, and a tablet terminal device, or a video camera.
  • the display device can be applied to electronic devices in various fields that display a video signal input from the outside or a video signal generated inside as an image or video.
  • Example 1-2 A simulation was performed in the same manner as in Experimental Example 1-1 except that the TN type liquid crystal in the liquid crystal panel 22 of the display switching unit 20 was set to a so-called O-mode. The results are shown in FIG. 10A (transmission state) and FIG. 10B (mirror surface state).
  • TN type liquid crystal including PC monitor is used in O-mode. This is because the O-mode is better in luminance characteristics and contrast viewing angle characteristics when a voltage is applied.
  • the luminance characteristics and contrast viewing angle characteristics in black to halftone are better in O-mode than in E-mode, and white (voltage E-mode is better than O-mode in luminance characteristics and contrast viewing angle characteristics when no voltage is applied.
  • the image quality in the black to halftone state has priority over the image quality in the white state.
  • TN type liquid crystal tends to cause gradation inversion, it is necessary to emphasize the viewing angle of black to halftone. Therefore, it seems that O-mode with good luminance characteristics and contrast viewing angle characteristics from black to halftone is widely used.
  • the TN liquid crystal is used for the display switching unit 20 in the display device 1, it is desirable to use it in E-mode as described above.
  • the reason is considered as follows.
  • the external light L1 sequentially passes through the absorption polarizing plate 23 and the liquid crystal panel 22 including the liquid crystal layer 22C to reflect.
  • Reflected by the polarizing plate 21 Reflected by the polarizing plate 21.
  • the light reflected by the reflective polarizing plate 21 once again passes through the liquid crystal panel 22 including the liquid crystal layer 22C, and then passes through the outermost absorption polarizing plate 23 to reach the outside. Therefore, the viewing angle characteristic equivalent to the case where two liquid crystal layers are superposed is effectively obtained.
  • the superiority of O-mode over E-mode at the time of voltage application is almost lost. That is, when used in the display switching unit 20, there is almost no difference between the O-mode and the E-mode when a voltage is applied, and the E-mode in the luminance characteristic and the contrast viewing angle characteristic in the transmission state (when no voltage is applied). Is better than O-mode. Furthermore, it is considered that the image quality in the transmissive state has priority over the image quality in the mirror surface state. Therefore, it can be said that the TN liquid crystal used in the display switching unit 20 is in E-mode.
  • Example 2-1 a sample of the display device 1 according to the above-described embodiment was actually manufactured, and the viewing angle characteristic regarding the chromaticity in the transmission state (screen state) was measured for the sample.
  • Ez-Contrast manufactured by ELDIM was used, and the viewing angle dependence of chromaticity at 0 ° (horizontal) azimuth and 45 ° azimuth was examined.
  • FIG. 11A the horizontal axis represents the polar angle ( ⁇ 80 ° to 0 ° to 80 °)
  • the vertical axis represents the difference ⁇ u′v ′ of the color difference ⁇ u′v ′.
  • Example 2-2 Except that the TN type liquid crystal in the liquid crystal panel 22 of the display switching unit 20 is a so-called O-mode, a sample was prepared in the same manner as in Experimental Example 2-1, and the same investigation was performed. The results are also shown in FIG. 11A (0 ° azimuth) and FIG. 11B (45 ° azimuth).
  • Example 3 In the display device 1 according to the above-described embodiment, a simulation was performed on the relationship between the applied voltage (AC voltage) to the display switching unit 20 and the reflectance. The result is shown in FIG. Table 2 shows the relationship among the applied voltage (AC voltage), frequency (Nz), and power consumption (W) applied to the display switching unit 20.
  • the applied voltage is desirably 5 V or more in order to obtain a stable mirror surface state (for example, a state in which the reflectance fluctuation is 0.2% or less).
  • Table 2 it is confirmed that by setting the frequency to 10 Hz or less, it is possible to realize power consumption less than half of the power consumption of 0.5 W (watt) required for the display device during standby. did it.
  • the present disclosure has been described with the embodiment and the experimental example, but the present disclosure is not limited to the above-described embodiment and the like, and various modifications are possible.
  • the configuration of the display device 1 and the electronic device 100 has been specifically described, but it is not necessary to include all the components, and other components may be included.
  • a reflective polarizing member that transmits a first linearly polarized light having a first polarization axis and reflects a second linearly polarized light having a second polarization axis that intersects the first polarization axis;
  • a TN (Twisted Nematic) type liquid crystal layer containing liquid crystal molecules aligned along the first polarization axis, and a liquid crystal panel having a pair of transparent electrodes facing each other with the TN type liquid crystal layer interposed therebetween;
  • An optical polarization device that sequentially absorbs the first linearly polarized light and transmits the second linearly polarized light.
  • the liquid crystal panel converts the first linearly polarized light into the second linearly polarized light and transmits the first linearly polarized light, and transmits the first linearly polarized light without converting it into the second linearly polarized light.
  • the optical device according to (1) wherein the optical device is switched to a second mode.
  • a control unit The control unit switches between the first mode and the second mode in the liquid crystal panel, applies a DC voltage between the pair of transparent electrodes, or 10 Hz between the pair of transparent electrodes. (Hertz)
  • the optical device according to (2) which is performed by applying the following AC voltage.
  • the said control part changes the increase / decrease speed of the said DC voltage, or the increase / decrease speed of the said AC voltage.
  • a display that emits first linearly polarized light having a first polarization axis as image light;
  • a display switching unit that is disposed to face the display unit and performs switching between an image display mode that transmits the first linearly polarized light and an external light reflection mode that reflects external light, and
  • the display unit includes a first absorptive polarizing member that transmits the first linearly polarized light and absorbs the second linearly polarized light having a second polarization axis that intersects the first polarization axis,
  • the display switching unit A reflective polarizing member that transmits the first linearly polarized light and reflects the second linearly polarized light;
  • a TN (Twisted Nematic) type liquid crystal layer containing liquid crystal molecules aligned along the first polarization axis, and a liquid crystal panel having a pair of transparent electrodes facing each other with the TN type liquid crystal layer interposed therebetween;
  • a display device comprising: a second absorptive polar
  • the display device includes a liquid crystal display element or an organic light emitting element.

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Abstract

Provided is a display device which has excellent display performance in an image display mode and in an outside light reflection mode. This display device is provided with: a display unit which emits, as image light, first linearly polarized light having a first polarization axis; and a display switching unit which is arranged to face the display unit and makes a switch between an image display mode wherein the first linearly polarized light is transmitted and an outside light reflection mode wherein the outside light is reflected. The display unit comprises a first absorptive polarizing member which transmits the first linearly polarized light and absorbs second linearly polarized light having a second polarization axis that intersects with the first polarization axis. The display switching unit comprises, sequentially in the direction toward the display unit: a second absorptive polarizing member which transmits the first linearly polarized light and absorbs the second linearly polarized light; a liquid crystal panel comprising a TN liquid crystal layer that contains liquid crystal molecules aligned along the first polarization axis and a pair of transparent electrodes facing each other with the TN liquid crystal layer being sandwiched therebetween; and a reflective polarizing member which transmits the first linearly polarized light and reflects the second linearly polarized light.

Description

光学装置、表示装置および電子機器Optical device, display device, and electronic apparatus
　本開示は、光を透過する透過状態と、光を反射する鏡面状態との切り替えを行う光学装置、ならびにそれを備えた表示装置および電子機器に関する。 The present disclosure relates to an optical device that switches between a transmissive state that transmits light and a mirror surface state that reflects light, and a display device and an electronic apparatus including the optical device.
　従来、２つの液晶パネルを重ね合せることによって、通常の画面状態（画像表示モードあるいは外光透過モード）と鏡面状態（外光反射モード）とを切り替え可能に構成した表示装置が知られている（例えば特許文献１，２参照）。そのような表示装置は、具体的には、例えば液晶表示部の観察者側に、液晶表示部から観察者に向かう順に反射型偏光板と液晶パネルと吸収型偏光板とが積層配置された表示切替部を備えている。 2. Description of the Related Art Conventionally, there has been known a display device configured to be able to switch between a normal screen state (image display mode or external light transmission mode) and a specular state (external light reflection mode) by overlapping two liquid crystal panels ( For example, see Patent Documents 1 and 2). Specifically, such a display device is, for example, a display in which a reflective polarizing plate, a liquid crystal panel, and an absorbing polarizing plate are stacked in order from the liquid crystal display unit to the viewer on the viewer side of the liquid crystal display unit. A switching unit is provided.
特開２００１―３１８３７４号公報JP 2001-318374 A 特開２００４―３７９４３号公報JP 2004-37943 A
　しかしながら、上記の表示装置においては、画像表示モード（外光透過モード）および外光反射モードのいずれにおいても、表示切替部における液晶パネルと吸収型偏光板とを順次透過した光を視認することとなる。このため、観察者に視認される画像光は、それらの液晶パネルおよび吸収型偏光板の透過特性の影響を受けることとなり、例えば吸収型偏光板の波長分散と液晶パネルの波長分散とに起因する色付きが発生し、表示品位に欠けるおそれがある。 However, in the above display device, in both the image display mode (external light transmission mode) and the external light reflection mode, the light sequentially transmitted through the liquid crystal panel and the absorption polarizing plate in the display switching unit is visually recognized. Become. For this reason, the image light visually recognized by the observer is affected by the transmission characteristics of the liquid crystal panel and the absorption polarizing plate, and is caused by, for example, the wavelength dispersion of the absorption polarizing plate and the wavelength dispersion of the liquid crystal panel. Coloring may occur and display quality may be lost.
　したがって、画像表示モード（外光透過モード）および外光反射モードのいずれにおいても優れた表示性能を有する表示装置および電子機器、ならびにそれらに好適に用いられる光学装置を提供することが望ましい。 Therefore, it is desirable to provide a display device and an electronic apparatus that have excellent display performance in both the image display mode (external light transmission mode) and the external light reflection mode, and an optical device suitably used for them.
　本開示の一実施形態としての光学装置は、第１の偏光軸を有する第１の直線偏光を透過すると共に第１の偏光軸と交差する第２の偏光軸を有する第２の直線偏光を反射する反射型偏光部材と、第１の偏光軸に沿って配向する液晶分子を含むＴＮ（Twisted Nematic）型液晶層、およびこのＴＮ型液晶層を挟んで対向する１対の透明電極を有する液晶パネルと、第１の直線偏光を吸収すると共に第２の直線偏光を透過させる透過型偏光部材とを順に有する。 An optical device according to an embodiment of the present disclosure transmits a first linearly polarized light having a first polarization axis and reflects a second linearly polarized light having a second polarization axis that intersects the first polarization axis. A liquid crystal panel having a reflective polarizing member, a TN (Twisted 型 Nematic) liquid crystal layer containing liquid crystal molecules aligned along the first polarization axis, and a pair of transparent electrodes facing each other with the TN liquid crystal layer interposed therebetween And a transmissive polarizing member that absorbs the first linearly polarized light and transmits the second linearly polarized light in order.
　本開示の一実施形態としての光学装置では、ＴＮ型液晶層における液晶分子が第１の偏光軸に沿って配向するようにしたので、光透過モードにおいて、その直前に配置された吸収型偏光部材を透過する第１の直線偏光がＴＮ型液晶層を透過する際、優れた視野角特性が得られる。 In the optical device according to an embodiment of the present disclosure, the liquid crystal molecules in the TN liquid crystal layer are aligned along the first polarization axis. Therefore, in the light transmission mode, the absorptive polarizing member disposed immediately before the light transmission mode. When the first linearly polarized light that transmits through the TN liquid crystal layer is transmitted, excellent viewing angle characteristics can be obtained.
　本開示の一実施形態としての表示装置は、画像光として第１の偏光軸を有する第１の直線偏光を出射する表示部と、その表示部と対向して配置され、第１の直線偏光を透過する画像表示モードと外光を反射する外光反射モードとの切り替えを行う表示切替部とを備える。ここで表示部は、第１の直線偏光を透過すると共に第１の偏光軸と交差する第２の偏光軸を有する第２の直線偏光を吸収する第１の吸収型偏光部材を有し、表示切替部は、第１の直線偏光を透過すると共に第２の直線偏光を吸収する第２の吸収型偏光部材と、第１の偏光軸に沿って配向する液晶分子を含むＴＮ型液晶層、およびそのＴＮ型液晶層を挟んで対向する１対の透明電極を有する液晶パネルと、第１の直線偏光を透過させると共に第２の直線偏光を反射する反射型偏光部材とを、表示部に近づく方向に順に有する。
　また、本開示の一実施形態としての電子機器は、上記本開示の一実施形態としての表示装置と、その表示装置を制御する制御部とを備えるものである。 A display device according to an embodiment of the present disclosure includes a display unit that emits first linearly polarized light having a first polarization axis as image light, and is disposed to face the display unit. A display switching unit that switches between an image display mode that transmits light and an external light reflection mode that reflects external light; Here, the display unit includes a first absorptive polarizing member that transmits the first linearly polarized light and absorbs the second linearly polarized light having the second polarization axis that intersects the first polarization axis. The switching unit includes a second absorptive polarizing member that transmits the first linearly polarized light and absorbs the second linearly polarized light, a TN-type liquid crystal layer that includes liquid crystal molecules aligned along the first polarization axis, and A liquid crystal panel having a pair of transparent electrodes facing each other with the TN liquid crystal layer interposed therebetween, and a reflective polarizing member that transmits the first linearly polarized light and reflects the second linearly polarized light, in a direction approaching the display unit In order.
An electronic apparatus as an embodiment of the present disclosure includes the display device as an embodiment of the present disclosure and a control unit that controls the display device.
　本開示の一実施形態としての表示装置および電子機器では、表示切替部により、画像表示モードと外光反射モードとの切り替えが行われる。ここで、ＴＮ型液晶層における液晶分子が第１の偏光軸に沿って配向するようにしたので、画像表示モードにおいて、その直前に配置された吸収型偏光部材を透過する第１の直線偏光がＴＮ型液晶層を透過する際、優れた視野角特性が得られる。 In the display device and the electronic apparatus as an embodiment of the present disclosure, the display switching unit switches between the image display mode and the external light reflection mode. Here, since the liquid crystal molecules in the TN type liquid crystal layer are aligned along the first polarization axis, in the image display mode, the first linearly polarized light that passes through the absorption polarizing member disposed immediately before the liquid crystal molecule is When transmitting through the TN type liquid crystal layer, excellent viewing angle characteristics are obtained.
　本開示の一実施形態としての光学装置によれば、外光透過モードにおける透過光の優れた視認性および外光反射モードにおける反射光の優れた視認性を発揮することができる。また本開示の一実施形態としての表示装置および電子機器によれば、画像表示モードおよび外光反射モードのいずれにおいても優れた表示性能を発揮することができる。 According to the optical device as one embodiment of the present disclosure, it is possible to exhibit excellent visibility of transmitted light in the external light transmission mode and excellent visibility of reflected light in the external light reflection mode. In addition, according to the display device and the electronic apparatus as an embodiment of the present disclosure, it is possible to exhibit excellent display performance in both the image display mode and the external light reflection mode.
　なお、本開示の効果はこれに限定されるものではなく、以下の記載のいずれの効果であってもよい。 Note that the effect of the present disclosure is not limited to this, and may be any of the effects described below.
本開示における第１の実施の形態に係る表示装置を表す断面図である。It is sectional drawing showing the display apparatus which concerns on 1st Embodiment in this indication. 図１に示した表示装置の作用を表す概念図である。It is a conceptual diagram showing the effect | action of the display apparatus shown in FIG. O-modeのＴＮ型液晶における、赤色、緑色および青色の各光の入射角を変えた場合の出射時の偏光状態を表した特性図である。FIG. 5 is a characteristic diagram illustrating a polarization state at the time of emission when an incident angle of each light of red, green, and blue is changed in an O-mode TN liquid crystal. E-modeのＴＮ型液晶における、赤色、緑色および青色の各光の入射角を変えた場合の出射時の偏光状態を表した特性図である。FIG. 6 is a characteristic diagram illustrating a polarization state at the time of emission when an incident angle of each of red, green, and blue light is changed in an E-mode TN liquid crystal. 極角６０°，方位４５°で入射した光の、O-modeのＴＮ型液晶層での偏光状態の変化を表す特性図である。It is a characteristic view showing the change of the polarization state in the O-mode TN type liquid crystal layer of the light incident at a polar angle of 60 ° and an azimuth of 45 °. 極角６０°，方位４５°で入射した光の、E-modeのＴＮ型液晶層での偏光状態の変化を表す特性図である。It is a characteristic view showing the change of the polarization state in the TN type liquid crystal layer of E-mode of light incident at a polar angle of 60 ° and an azimuth of 45 °. O-modeのＴＮ型液晶における液晶配向軸と偏光板の透過軸との関係を表す説明図である。It is explanatory drawing showing the relationship between the liquid crystal aligning axis in the TN type liquid crystal of O-mode, and the transmission axis of a polarizing plate. E-modeのＴＮ型液晶における液晶配向軸と偏光板の透過軸との関係を表す説明図である。It is explanatory drawing showing the relationship between the liquid-crystal orientation axis | shaft in the TN type | mold liquid crystal of E-mode, and the transmission axis of a polarizing plate. 図１に示した表示切替部における切替動作時の電圧変化を表す特性図である。It is a characteristic view showing the voltage change at the time of the switching operation | movement in the display switching part shown in FIG. 図１に示した表示切替部における切替動作時の電圧変化を表す他の特性図である。It is another characteristic view showing the voltage change at the time of the switching operation in the display switching unit shown in FIG. 参考例としての表示切替部における切替動作時の電圧変化を表す特性図である。It is a characteristic view showing the voltage change at the time of the switching operation | movement in the display switching part as a reference example. 参考例としての表示切替部における切替動作時の電圧変化を表す他の特性図である。It is another characteristic view showing the voltage change at the time of the switching operation | movement in the display switching part as a reference example. 本開示の表示装置を備えた電子機器の構成例を表す概念図である。It is a conceptual diagram showing the structural example of the electronic device provided with the display apparatus of this indication. 実験例１－１における透過状態での色度および輝度の視野角特性を表す特性図である。FIG. 10 is a characteristic diagram illustrating viewing angle characteristics of chromaticity and luminance in a transmission state in Experimental Example 1-1. 実験例１－１における鏡面状態での色度および輝度の視野角特性を表す特性図である。FIG. 10 is a characteristic diagram illustrating viewing angle characteristics of chromaticity and luminance in a mirror state in Experimental Example 1-1. 実験例１－２における透過状態での色度および輝度の視野角特性を表す特性図である。FIG. 10 is a characteristic diagram illustrating viewing angle characteristics of chromaticity and luminance in a transmission state in Experimental Example 1-2. 実験例１－２における鏡面状態での色度および輝度の視野角特性を表す特性図である。FIG. 10 is a characteristic diagram illustrating viewing angle characteristics of chromaticity and luminance in a mirror state in Experimental Example 1-2. 実験例２－１，２－２における０°方位での色度の視野角依存性を表す特性図である。It is a characteristic diagram showing the viewing angle dependence of chromaticity at 0 ° azimuth in Experimental Examples 2-1 and 2-2. 実験例２－１，２－２における４５°方位での色度の視野角依存性を表す特性図である。FIG. 11 is a characteristic diagram showing viewing angle dependence of chromaticity at 45 ° azimuth in Experimental Examples 2-1 and 2-2. 実験例３における、表示切替部に対する印加電圧と反射率との関係を表す特性図である。It is a characteristic view showing the relationship between the applied voltage with respect to the display switching part in Example 3 of an experiment, and a reflectance.
　以下、本開示の実施の形態について図面を参照して詳細に説明する。なお、説明は以下の順序で行う。
１．実施の形態（表示切替部において、吸収型偏光板の透過軸と反射型偏光板の透過軸とが直交する例）
２．適用例（電子機器）
３．実験例 Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be given in the following order.
1. Embodiment (example in which the transmission axis of the absorption polarizing plate and the transmission axis of the reflection polarizing plate are orthogonal to each other in the display switching unit)
2. Application example (electronic equipment)
3. Experimental example
＜１．実施の形態＞
［表示装置１の構成］
　図１は、本開示の一実施の形態としての表示装置１の断面を含む全体構成を表したものである。また図２は、表示装置１の作用を表す概念図である。この表示装置１は、２つの液晶パネルを重ね合せることにより画面状態と鏡面状態とを切替可能に構成したものである。具体的には、表示装置１は、互いの主面同士が重なり合うように対向配置された表示部１０および表示切替部２０を備える。表示部１０は所定の表示態様を形成する画像光を観察者へ向けて出射するものであり、表示切替部２０は表示部１０の観察者側に配置され、表示部１０からの画像光を透過する画像表示モードと外光を反射する外光反射モードとの切り替えを行うものである。表示装置１は、切替駆動部３０と制御部４０とをさらに備えており、制御部４０からの指令によって切替駆動部３０が表示切替部２０における切り替え動作が行われるようになっている。切替駆動部３０は、表示切替部２０に設けられた液晶パネル２２を駆動するものである。切替駆動部３０は、液晶パネル２２に供給する印加電圧を制御するものであり、例えば液晶パネル２２の対向する一対の透明電極間にしきい値電圧以上の電圧を印加するか否かを決定するものである。なお、表示部１０と表示切替部２０とは、相互に少なくとも一部が重なっていればよい。 <1. Embodiment>
[Configuration of Display Device 1]
FIG. 1 illustrates an overall configuration including a cross section of a display device 1 as an embodiment of the present disclosure. FIG. 2 is a conceptual diagram showing the operation of the display device 1. The display device 1 is configured such that a screen state and a mirror surface state can be switched by overlapping two liquid crystal panels. Specifically, the display device 1 includes a display unit 10 and a display switching unit 20 that are arranged to face each other so that their main surfaces overlap each other. The display unit 10 emits image light forming a predetermined display mode toward an observer, and the display switching unit 20 is disposed on the viewer side of the display unit 10 and transmits image light from the display unit 10. Switching between an image display mode to be performed and an external light reflection mode to reflect external light. The display device 1 further includes a switching drive unit 30 and a control unit 40, and the switching drive unit 30 performs a switching operation in the display switching unit 20 according to a command from the control unit 40. The switching drive unit 30 drives the liquid crystal panel 22 provided in the display switching unit 20. The switching drive unit 30 controls the applied voltage supplied to the liquid crystal panel 22, and determines whether or not to apply a voltage equal to or higher than the threshold voltage between a pair of opposing transparent electrodes of the liquid crystal panel 22, for example. It is. In addition, the display part 10 and the display switching part 20 should just overlap at least one part mutually.
（表示部１０）
　本実施の形態では、表示部１０として液晶表示素子を用いた場合について説明する。但し、本技術では、表示部１０として例えばエレクトロルミネッセンス素子やプラズマディスプレイパネル、あるいは電子ペーパー等の各種の表示機構が適用され得る。 (Display unit 10)
In the present embodiment, a case where a liquid crystal display element is used as the display unit 10 will be described. However, in the present technology, various display mechanisms such as an electroluminescence element, a plasma display panel, or electronic paper can be applied as the display unit 10.
　表示部１０の駆動モードとしては、ＴＦＴ（Thin Film Transistor）やＴＦＤ（Thin Film Diode）等の能動素子を用いたアクティブマトリクス駆動等のアクティブ駆動モードと、上記のような能動素子を用いない単純駆動若しくはマルチプレックス駆動等のパッシブ駆動モードとのいずれであってもよい。さらに、表示部１０のパネル構造としては、透過型パネル、反射型パネルまたは反射半透過型パネルのいずれであってもよい。本実施の形態では透過型パネルを用いた場合について説明する。 The driving mode of the display unit 10 includes an active driving mode such as active matrix driving using active elements such as TFT (Thin Film Transistor) and TFD (Thin Film Film Diode), and simple driving without using the active elements as described above. Or any of passive drive modes, such as a multiplex drive, may be sufficient. Furthermore, the panel structure of the display unit 10 may be any of a transmissive panel, a reflective panel, and a reflective transflective panel. In this embodiment, the case where a transmissive panel is used will be described.
　表示部１０は、例えば図１に示したように、表示切替部２０に近い位置から順に吸収型偏光板１１と液晶パネル１３と吸収型偏光板１４とバックライト１５とを有する。吸収型偏光板１１と液晶パネル１３の間に位相差板がさらに配置されていてもよい。 For example, as shown in FIG. 1, the display unit 10 includes an absorption polarizing plate 11, a liquid crystal panel 13, an absorption polarizing plate 14, and a backlight 15 in order from a position close to the display switching unit 20. A retardation plate may be further disposed between the absorption polarizing plate 11 and the liquid crystal panel 13.
　液晶パネル１３は、透明電極基板１３Ａと基板１３Ｂとの間に液晶層１３Ｃが挟持された構造を有する。透明電極基板１３Ａおよび透明電極基板１３Ｂは例えばガラス（石英を含む）などの透明基板に透明導電層が形成されたものであり、所定の間隔（例えば１．５μｍから１０μｍ程度）を有するように対向配置され、シール材（図示せず）などによって貼り合わされている。このように、透明電極基板１３Ａ，１３Ｂによって液晶層１３Ｃに電界を印加することができるように構成されている。 The liquid crystal panel 13 has a structure in which a liquid crystal layer 13C is sandwiched between a transparent electrode substrate 13A and a substrate 13B. The transparent electrode substrate 13A and the transparent electrode substrate 13B are obtained by forming a transparent conductive layer on a transparent substrate such as glass (including quartz) and facing each other so as to have a predetermined interval (for example, about 1.5 μm to 10 μm). It arrange | positions and it is bonded together by the sealing material (not shown) etc. In this way, the transparent electrode substrates 13A and 13B are configured so that an electric field can be applied to the liquid crystal layer 13C.
　液晶パネル１３の液晶層１３Ｃにおける液晶モードとしては、例えばＴＮ（Twisted Nematic）モード、ＶＡ（Vertical Alignment）モード、ＩＰＳ（In Plane Switching）モード、ＦＦＳ（Fringe Field Switching）モード、ＳＴＮ（Super Twisted Nematic）モード、またはＥＣＢ（Electrically Controlled Birefringence）モードを用いることができる。これらの液晶モードを有する液晶表示素子は、偏光板を用いて表示態様を実現するように構成されているので、比較的低い駆動電圧でありながら高い表示品位を得ることができるので好ましい。この中でＶＡモードが特に好ましい。ＶＡモードの液晶表示素子は、表示部１０の吸収型偏光板１１，１４にストレスが負荷された場合に、他の液晶モード（例えばＩＰＳモード）に比べて黒浮きしにくいからである。ここで、黒浮きとは、黒表示の際に一部に光漏れが生じることをいう。表示装置１では、表示部１０と表示切替部２０とが例えば第３の樹脂層３３（以下、単に樹脂層３３という。）により貼り合わされている。表示部１０と表示切替部２０との貼り合わせの際、例えばゲル状の樹脂が硬化・収縮して樹脂層３３を形成するが、その樹脂が硬化および収縮するのに伴って表示部１０の偏光板（特に吸収型偏光板１１）にストレスを与えてしまう。ここで、例えば表示部１０としてＩＰＳモードの液晶表示素子を用いると表示領域の角隅部に黒浮きが僅かに発生することがあるが、表示部１０としてＶＡモードの液晶表示素子を用いることにより黒浮きを抑制することができる。また、表示部１０（吸収型偏光板１１）と表示切替部２０（後出の反射型偏光板２１）とが樹脂層３３を介して貼り合わされているので、貼り合わせによる吸収型偏光板１１と反射型偏光板２１との界面近傍における凹凸の発生を抑制できる。そのような凹凸の発生を抑制することにより、凹凸に起因する鏡状態（外光反射モード）での滲みを低減できる。樹脂層３３としては、例えばＬｉｎｔｅｃ社製の高透明基材レステープＣＴＬ－ＮＣ１０３や、ＤＩＣ社製の基材レス光学用両面接着テープＤＡＩＴＡＣ　ＺＢ７０１０Ｗ－１０などを用いることができる。 Examples of the liquid crystal mode in the liquid crystal layer 13C of the liquid crystal panel 13 include a TN (Twisted Nematic) mode, a VA (Vertical Alignment) mode, an IPS (In Plane Switching) mode, an FFS (Fringe Field Switching) mode, and an STN (Super Twisted Nematic). Mode, or ECB (Electrically Controlled Birefringence) mode can be used. Since the liquid crystal display element having these liquid crystal modes is configured to realize a display mode using a polarizing plate, it is preferable because a high display quality can be obtained with a relatively low driving voltage. Of these, the VA mode is particularly preferable. This is because the VA mode liquid crystal display element is less likely to float black when stress is applied to the absorption polarizing plates 11 and 14 of the display unit 10 as compared with other liquid crystal modes (for example, IPS mode). Here, “black floating” means that light leaks in part during black display. In the display device 1, the display unit 10 and the display switching unit 20 are bonded together by, for example, a third resin layer 33 (hereinafter simply referred to as a resin layer 33). When the display unit 10 and the display switching unit 20 are bonded to each other, for example, a gel-like resin is cured and contracted to form the resin layer 33. As the resin is cured and contracted, the polarization of the display unit 10 is increased. Stress is applied to the plate (particularly the absorption-type polarizing plate 11). Here, for example, when an IPS mode liquid crystal display element is used as the display unit 10, black floating may occur slightly in the corners of the display area. However, by using a VA mode liquid crystal display element as the display unit 10, Black float can be suppressed. Moreover, since the display part 10 (absorption type polarizing plate 11) and the display switch part 20 (reflective type polarizing plate 21 mentioned later) are bonded together through the resin layer 33, the absorption type polarizing plate 11 by bonding and Generation of irregularities in the vicinity of the interface with the reflective polarizing plate 21 can be suppressed. By suppressing the occurrence of such unevenness, bleeding in the mirror state (external light reflection mode) due to the unevenness can be reduced. As the resin layer 33, for example, a highly transparent substrate-less tape CTL-NC103 manufactured by Lintec, or a double-sided adhesive tape for substrate-less optics DAITAC ZB7010W-10 manufactured by DIC can be used.
　吸収型偏光板１１，１４は、液晶装置１の構成上、必要とされる配置（例えば直交ニコル配置）に設定される。吸収型偏光板１１，１４は透過偏光軸１１Ｊ，１４Ｊをそれぞれ有し、それらの透過偏光軸１１Ｊ，１４Ｊと平行な振動面を有する直線偏光を透過し、透過偏光軸１１Ｊ，１４Ｊと交差する（好ましくは直交する）方向に平行な振動面を有する直線偏光を吸収するものである。吸収型偏光板１１，１４としては、例えば延伸したポリビニルアルコールにヨウ素を吸収させることにより偏光機能を付与した膜の両面に、トリアセチルセルロースの保護層を施したものを用いることができる。 The absorptive polarizing plates 11 and 14 are set in a required arrangement (for example, a crossed Nicol arrangement) in the configuration of the liquid crystal device 1. The absorptive polarizing plates 11 and 14 have transmission polarization axes 11J and 14J, respectively, transmit linearly polarized light having vibration planes parallel to the transmission polarization axes 11J and 14J, and cross the transmission polarization axes 11J and 14J ( It absorbs linearly polarized light having a vibration plane parallel to the (preferably orthogonal) direction. As the absorption polarizing plates 11 and 14, for example, a film obtained by applying a protective layer of triacetyl cellulose on both surfaces of a film imparted with a polarizing function by absorbing iodine into stretched polyvinyl alcohol can be used.
　バックライト１５は、背後から液晶パネル１３に対してほぼ均一な照度で照明を行うことができるものであればよい。例えば、導光板と、この導光板の端面部に配置された光源とを含む端面発光型のバックライトや、導光板と、この導光板の背面に配置された光源とを含む背面発光型のバックライトなどが挙げられる。 The backlight 15 only needs to be able to illuminate the liquid crystal panel 13 with substantially uniform illuminance from behind. For example, an edge-emitting backlight including a light guide plate and a light source disposed on an end surface portion of the light guide plate, or a back-emitting backlight including a light guide plate and a light source disposed on the back surface of the light guide plate Light etc. are mentioned.
（表示切替部２０）
　表示切替部２０ は、上記の表示部１０から観察者に向けて反射型偏光板２１と液晶パネル２２と吸収型偏光板２３とが順に配置されたものである。なお、吸収型偏光板２３と液晶パネル２２との間、および反射型偏光板２１と液晶パネル２２との間の少なくとも一方に、視野角向上フィルムを配置してもよい。 (Display switching unit 20)
The display switching unit 20 includes a reflective polarizing plate 21, a liquid crystal panel 22, and an absorption polarizing plate 23 arranged in this order from the display unit 10 toward the viewer. A viewing angle improving film may be disposed between at least one of the absorption type polarizing plate 23 and the liquid crystal panel 22 and between at least one of the reflection type polarizing plate 21 and the liquid crystal panel 22.
　反射型偏光板２１は透過偏光軸２１Ｊを有する。反射型偏光板２１は、その透過偏光軸２１Ｊと平行な振動面を有する直線偏光を透過する一方、透過偏光軸２１Ｊと交差する（好ましくは直交する）方向に平行な振動面を有する直線偏光を反射するものである。具体的には、反射型偏光板２１は、表示部１０から出射される第１の直線偏光Ｌｐ（後出）は透過し、これと直交する透過偏光軸を有する第２の直線偏光Ｌｓ（後出）は鏡面反射する機能を有する。そのような部材としては、例えば国際出願の国際公開番号：ＷＯ９５／２７９１９号に開示されている異なる複屈折性高分子フィルムを交互に複数層積層した複屈折反射型偏光フィルム、あるいは、コレステリック液晶層の表と裏に１／４波長板を配置したものを用いることができる。 The reflective polarizing plate 21 has a transmission polarization axis 21J. The reflective polarizing plate 21 transmits linearly polarized light having a vibration plane parallel to the transmission polarization axis 21J, while linearly polarized light having a vibration plane parallel to the direction intersecting (preferably orthogonal to) the transmission polarization axis 21J. It is a reflection. Specifically, the reflection-type polarizing plate 21 transmits the first linearly polarized light Lp (described later) emitted from the display unit 10 and the second linearly polarized light Ls (rear) having a transmission polarization axis perpendicular thereto. Out) has the function of specular reflection. As such a member, for example, a birefringence reflective polarizing film in which a plurality of different birefringent polymer films disclosed in International Publication No. WO95 / 27919 is alternately laminated, or a cholesteric liquid crystal layer is used. The one where the quarter wavelength plate is arrange | positioned to the front and back of this can be used.
　反射型偏光板２１として使用される複屈折反射型偏光フィルムとしては、例えば３Ｍ社（米国）からＤＢＥＦという商品名で市販されているものが挙げられる。このような複屈折反射型偏光フィルムは、所定の直線偏光を透過し、その直線偏光の偏光軸と直交する偏光軸を有する直線偏光を鏡面反射する機能を有する。 Examples of the birefringent reflective polarizing film used as the reflective polarizing plate 21 include those commercially available from 3M (USA) under the trade name DBEF. Such a birefringent reflective polarizing film has a function of transmitting predetermined linearly polarized light and specularly reflecting linearly polarized light having a polarization axis orthogonal to the polarization axis of the linearly polarized light.
　一方、反射型偏光板２１として、コレステリック液晶層の表と裏に１／４波長板を配置したもので構成する場合、配向処理された２枚の透明基板間に低分子コレステリック液晶を収めた液晶セルや、高分子コレステリック液晶層をガラスあるいは透明樹脂等の平坦かつ光学的に等方で透明な基板上に形成したものを用いることができる。コレステリック液晶層は、ヘリカルな分子配列に基づく特異な光学特性を示すもので、ヘリカル軸に平行に入射した光が、コレステリック螺旋の回転方向に応じて、一方の回転方向の円偏光は反射し、他方は透過するという選択反射を示すものである。選択反射の波長域は、分子配列のピッチによって決まるので、可視波長域全域で選択反射が起こるようにするためには、ピッチの異なる複数のコレステリック液晶層を積層して用いることが必要である。この場合、可視波長域全域での選択反射を得るために、ピッチの異なるコレステリック液晶層を複数層重ねる代わりにAsia Display95 Digest, p735, The Institute of Television Engineers of Japan (ITE) &The Society for Information Display (SID) に記載されているような、ピッチを連続的に変化させたコレステリック液晶層を用いてもよい。 On the other hand, in the case where the reflective polarizing plate 21 is composed of a cholesteric liquid crystal layer with a quarter-wave plate disposed on the front and back, a liquid crystal containing a low-molecular cholesteric liquid crystal between two aligned transparent substrates. A cell or a polymer cholesteric liquid crystal layer formed on a flat and optically isotropic transparent substrate such as glass or transparent resin can be used. The cholesteric liquid crystal layer exhibits unique optical characteristics based on a helical molecular arrangement. Light incident in parallel to the helical axis reflects circularly polarized light in one rotational direction according to the rotational direction of the cholesteric helix, The other shows selective reflection of transmitting. Since the wavelength range of selective reflection is determined by the pitch of the molecular arrangement, it is necessary to stack and use a plurality of cholesteric liquid crystal layers having different pitches in order to cause selective reflection over the entire visible wavelength range. In this case, instead of stacking multiple cholesteric liquid crystal layers with different pitches in order to obtain selective reflection in the entire visible wavelength range, Asia 重 ね Display 95 Digest, p735, The Institute Television Engineers of Japan (ITE) & The Society for Information Display A cholesteric liquid crystal layer whose pitch is continuously changed as described in (SID) IV may be used.
　また、反射型偏光板２１として、コレステリック液晶層の表と裏に１／４波長板を配置したものを用いる場合、コレステリック液晶層の裏側、すなわち表示部１０側に配置される１／４波長板は、その遅相軸を以下のような方向に設定するとよい。すなわち、表示部１０から出射して反射型偏光板２１に入射する第１の直線偏光Ｌｐを、コレステリック液晶層を透過する円偏光に変換するように、その遅相軸を配置する。一方、同じくコレステリック液晶層の表側、すなわち液晶パネル２２側に配置される１／４波長板は、コレステリック液晶層を透過する円偏光が第１の直線偏光Ｌｐへ変換されるように、その遅相軸を配置する。 Further, in the case of using a reflection type polarizing plate 21 in which a quarter wavelength plate is disposed on the front and back of the cholesteric liquid crystal layer, a quarter wavelength plate disposed on the back side of the cholesteric liquid crystal layer, that is, on the display unit 10 side. The slow axis may be set in the following direction. That is, the slow axis is arranged so that the first linearly polarized light Lp emitted from the display unit 10 and incident on the reflective polarizing plate 21 is converted into circularly polarized light that passes through the cholesteric liquid crystal layer. On the other hand, the quarter-wave plate similarly disposed on the front side of the cholesteric liquid crystal layer, that is, on the liquid crystal panel 22 side, has a slow phase so that the circularly polarized light transmitted through the cholesteric liquid crystal layer is converted into the first linearly polarized light Lp. Arrange the axes.
　このようにコレステリック液晶層の表と裏に１／４波長板を配置した構成の反射型偏光板２１に第２の直線偏光Ｌｓが入射した場合、その第２の直線偏光Ｌｓは、１／４波長板の作用によりコレステリック液晶層を透過する円偏光とは逆周りの円偏光に変換される。このため、その第２の直線偏光Ｌｓは、コレステリック液晶層においてで選択的に反射される。コレステリック液晶層で反射した円偏光は、再び１／４波長板を透過する際、その１／４波長板の作用で第２の直線偏光Ｌｓに変換される。 When the second linearly polarized light Ls is incident on the reflective polarizing plate 21 having the structure in which the quarter wavelength plates are arranged on the front and back of the cholesteric liquid crystal layer in this way, the second linearly polarized light Ls is 1/4. By the action of the wave plate, it is converted into circularly polarized light that is opposite to the circularly polarized light that passes through the cholesteric liquid crystal layer. Therefore, the second linearly polarized light Ls is selectively reflected by the cholesteric liquid crystal layer. When the circularly polarized light reflected by the cholesteric liquid crystal layer passes through the quarter wavelength plate again, it is converted into the second linearly polarized light Ls by the action of the quarter wavelength plate.
　なお、この構成の反射型偏光板２１に使用する１／４波長板は、可視波長の全域において１／４波長板として機能するものを用いることが望ましい。１／４波長板としては、可視波長域において高い透過率を有する、延伸した高分子フィルム、例えばポリビニルアルコール、ポリカーボネート、ポリサルフォン、ポリスチレン、ポリアリレート等を用いることができる。このほかにも雲母、水晶、分子軸を一方向に揃えて配向した液晶層等を用いることができる。 In addition, as for the quarter wavelength plate used for the reflection type polarizing plate 21 of this structure, it is desirable to use what functions as a quarter wavelength plate in the whole visible wavelength range. As the quarter-wave plate, a stretched polymer film having a high transmittance in the visible wavelength region, such as polyvinyl alcohol, polycarbonate, polysulfone, polystyrene, polyarylate, or the like can be used. In addition, mica, quartz, a liquid crystal layer with molecular axes aligned in one direction, and the like can be used.
　また、一般に１／４波長板を構成する材質の屈折率の波長依存性（以下、波長分散）により、一種類の位相差板で可視波長の全域に対し１／４波長板として機能する位相差板を構成することは困難である。しかし、波長分散の異なる少なくとも２種類の位相差板をその光学軸を直交するように貼り合わせることにより、広い波長域において１／４波長板として機能するよう構成したものを使用すればよい。 In general, due to the wavelength dependence of the refractive index of the material constituting the quarter wavelength plate (hereinafter referred to as wavelength dispersion), one type of retardation plate functions as a quarter wavelength plate for the entire visible wavelength range. It is difficult to construct a plate. However, what is necessary is just to use what was comprised so that it might function as a quarter wavelength plate in a wide wavelength range by bonding together at least 2 types of phase contrast plates from which wavelength dispersion differs so that the optical axis may intersect perpendicularly.
　反射型偏光板２１と液晶パネル２２とは、例えば２５μｍ以下の厚さを有する第１の樹脂層３１（以下、単に樹脂層３１という。）を介して貼り合わされているとよい。貼り合わせによる液晶パネル２２と反射型偏光板２１との界面近傍における凹凸の発生を抑制できるからである。そのような凹凸の発生を抑制することにより、凹凸に起因する鏡状態（外光反射モード）での滲みを低減できる。このような樹脂層３１としては、例えばＬｉｎｔｅｃ社製の高透明基材レステープＣＴＬ－ＮＣ１０３や、ＤＩＣ社製の基材レス光学用両面接着テープＤＡＩＴＡＣ　ＺＢ７０１０Ｗ－１０などを用いることができる。 The reflective polarizing plate 21 and the liquid crystal panel 22 may be bonded together via a first resin layer 31 (hereinafter simply referred to as a resin layer 31) having a thickness of, for example, 25 μm or less. This is because the occurrence of unevenness in the vicinity of the interface between the liquid crystal panel 22 and the reflective polarizing plate 21 due to bonding can be suppressed. By suppressing the occurrence of such unevenness, bleeding in the mirror state (external light reflection mode) due to the unevenness can be reduced. As such a resin layer 31, for example, a highly transparent substrate-less tape CTL-NC103 manufactured by Lintec, a double-sided adhesive tape for substrate-less optical DAITAC ZB7010W-10 manufactured by DIC, or the like can be used.
　吸収型偏光板２３は透過偏光軸２３Ｊを有する。吸収型偏光板２３は、その透過偏光軸２３Ｊと平行な振動面を有する直線偏光を透過する一方、透過偏光軸２３Ｊと交差する（好ましくは直交する）方向に平行な振動面を有する直線偏光を吸収するものである。具体的には、吸収型偏光板２３は第１の直線偏光Ｌｐを吸収し、これと直交する第２の直線偏光Ｌｓは透過する機能を有する。 The absorption polarizing plate 23 has a transmission polarization axis 23J. The absorptive polarizing plate 23 transmits linearly polarized light having a vibration plane parallel to the transmission polarization axis 23J, while linearly polarized light having a vibration plane parallel to a direction intersecting (preferably orthogonal) to the transmission polarization axis 23J. Absorb. Specifically, the absorption polarizing plate 23 has a function of absorbing the first linearly polarized light Lp and transmitting the second linearly polarized light Ls orthogonal thereto.
　反射型偏光板２１と吸収型偏光板２３との間に挟まれた液晶パネル２２は、第１の直線偏光Ｌｐを、それと直交する偏光軸を有する第２の直線偏光Ｌｓへ変換して透過させる第１のモードと、第１の直線偏光Ｌｐを第２の直線偏光Ｌｓへ変換せずにそのまま透過させる第２のモードとの切り替えを行うものである。液晶パネル２２は、透明電極基板２２Ａと透明電極基板２２Ｂとの間に液晶層２２Ｃが挟持された構造を有し、液晶層２２Ｃに所定の電界を印加できるようになっている。透明電極基板２２Ａおよび透明電極基板２２Ｂは、例えばガラス（石英を含む）などの透明基板にＩＴＯなどの透明導電層が形成されたものであり、それぞれ駆動部３０と接続され、制御部４０による制御により電圧が印加されるようになっている。透明電極基板２２Ａおよび透明電極基板２２Ｂは、所定の間隔（例えば１．５μｍから１０μｍ程度）を有するように対向配置され、シール材（図示せず）などによって貼り合わされている。 The liquid crystal panel 22 sandwiched between the reflection-type polarizing plate 21 and the absorption-type polarizing plate 23 converts the first linearly polarized light Lp into a second linearly polarized light Ls having a polarization axis perpendicular to the first linearly polarized light Lp and transmits the converted light. Switching between the first mode and the second mode in which the first linearly polarized light Lp is transmitted as it is without being converted into the second linearly polarized light Ls is performed. The liquid crystal panel 22 has a structure in which a liquid crystal layer 22C is sandwiched between a transparent electrode substrate 22A and a transparent electrode substrate 22B so that a predetermined electric field can be applied to the liquid crystal layer 22C. The transparent electrode substrate 22A and the transparent electrode substrate 22B are formed by forming a transparent conductive layer such as ITO on a transparent substrate such as glass (including quartz), and are connected to the driving unit 30 and controlled by the control unit 40. Thus, a voltage is applied. The transparent electrode substrate 22A and the transparent electrode substrate 22B are opposed to each other so as to have a predetermined interval (for example, about 1.5 μm to 10 μm), and are bonded together by a seal material (not shown).
　液晶層２２Ｃは、透過偏光軸２３Ｊに沿って配向する液晶分子を含むＴＮ（Twisted Nematic）型液晶層である。したがって、液晶パネル２２の表示モードはＴＮモードである。すなわち、液晶層２２Ｃは、透過偏光軸２３Ｊに対して実質的に平行をなす配向軸２２Ｊを有する。また、液晶層２２Ｃにおける液晶分子は、５°以下のプレチルト角を有するとよい。 The liquid crystal layer 22C is a TN (Twisted Nematic) type liquid crystal layer including liquid crystal molecules aligned along the transmission polarization axis 23J. Therefore, the display mode of the liquid crystal panel 22 is the TN mode. That is, the liquid crystal layer 22C has an alignment axis 22J that is substantially parallel to the transmission polarization axis 23J. The liquid crystal molecules in the liquid crystal layer 22C may have a pretilt angle of 5 ° or less.
　液晶パネル２２と吸収型偏光板２３とは、例えば２５μｍ以下の厚さを有する第２の樹脂層３２（以下、単に樹脂層３２という。）を介して貼り合わされているとよい。貼り合わせによる液晶パネル２２と吸収型偏光板２３との界面近傍における凹凸の発生を抑制できるからである。そのような凹凸の発生を抑制することにより、凹凸に起因する鏡面状態（外光反射モード）での滲みを低減できる。このような樹脂層３２としては、例えばＬｉｎｔｅｃ社製の高透明基材レステープＣＴＬ－ＮＣ１０３や、ＤＩＣ社製の基材レス光学用両面接着テープＤＡＩＴＡＣ　ＺＢ７０１０Ｗ－１０またはＤＡＩＴＡＣ　ＺＢ７０１１Ｗなどを用いることができる。 The liquid crystal panel 22 and the absorption polarizing plate 23 may be bonded together via a second resin layer 32 (hereinafter simply referred to as a resin layer 32) having a thickness of, for example, 25 μm or less. This is because the occurrence of unevenness in the vicinity of the interface between the liquid crystal panel 22 and the absorption-type polarizing plate 23 due to the bonding can be suppressed. By suppressing the occurrence of such unevenness, it is possible to reduce bleeding in a mirror surface state (external light reflection mode) due to the unevenness. As such a resin layer 32, for example, a highly transparent substrate-less tape CTL-NC103 manufactured by Lintec, a double-sided adhesive tape for substrate-less optical DAITAC ZB7010W-10 or DAITAC ZB7011W manufactured by DIC, etc. can be used. .
　表示切替部２０では、液晶パネル２２と吸収型偏光板２３との間、および液晶パネル２２と反射型偏光板２１との間にそれぞれ位相差板（図示せず）が配置されていてもよい。 In the display switching unit 20, a retardation plate (not shown) may be disposed between the liquid crystal panel 22 and the absorption polarizing plate 23 and between the liquid crystal panel 22 and the reflection polarizing plate 21.
　反射型偏光板２１および吸収型偏光板１１は、反射型偏光板２１の透過偏光軸２１Ｊと吸収型偏光板１１の透過偏光軸１１Ｊとが実質的に平行となり、または、反射型偏光板２１の透過偏光軸２１Ｊと吸収型偏光板１１の透過偏光軸１１Ｊとが実質的に直交するように配置されていることが好ましい。また、表示装置１では、吸収型偏光板１１の透過偏光軸と吸収型偏光板１４の透過偏光軸とは互いに実質的に直交していることが望ましい。したがって、反射型偏光板２１の透過偏光軸と吸収型偏光板１１の透過偏光軸とが実質的に平行である場合、反射型偏光板２１の透過偏光軸２１Ｊと吸収型偏光板１４の透過偏光軸１４Ｊとは実質的に直交しているとよい。一方、反射型偏光板２１の透過偏光軸２１Ｊと吸収型偏光板１１の透過偏光軸１１Ｊとが実質的に直交している場合、反射型偏光板２１の透過偏光軸２１Ｊと吸収型偏光板１４の透過偏光軸１４Ｊとは実質的に平行であるとよい。 In the reflection-type polarizing plate 21 and the absorption-type polarizing plate 11, the transmission polarization axis 21J of the reflection-type polarization plate 21 and the transmission polarization axis 11J of the absorption-type polarization plate 11 are substantially parallel, or It is preferable that the transmission polarization axis 21 </ b> J and the transmission polarization axis 11 </ b> J of the absorptive polarizing plate 11 are arranged so as to be substantially orthogonal to each other. In the display device 1, it is desirable that the transmission polarization axis of the absorption polarizing plate 11 and the transmission polarization axis of the absorption polarizing plate 14 are substantially orthogonal to each other. Therefore, when the transmission polarization axis of the reflection-type polarizing plate 21 and the transmission polarization axis of the absorption-type polarization plate 11 are substantially parallel, the transmission polarization axis 21J of the reflection-type polarization plate 21 and the transmission polarization of the absorption-type polarization plate 14 The axis 14J may be substantially orthogonal. On the other hand, when the transmission polarization axis 21J of the reflection-type polarizing plate 21 and the transmission polarization axis 11J of the absorption-type polarization plate 11 are substantially orthogonal, the transmission polarization axis 21J of the reflection-type polarization plate 21 and the absorption-type polarization plate 14 The transmission polarization axis 14J is preferably substantially parallel to the transmission polarization axis 14J.
　表示切替部２０の駆動モードとしては、表示部１０の駆動モードと同様にＴＦＴやＴＦＤ等の能動素子を用いたアクティブマトリクス駆動等のアクティブ駆動モードと、上記のような能動素子を用いない単純駆動もしくはマルチプレックス駆動等のパッシブ駆動モードのいずれであってもよい。 As the drive mode of the display switching unit 20, as in the drive mode of the display unit 10, an active drive mode such as an active matrix drive using active elements such as TFT and TFD, and a simple drive without using the active elements as described above. Or any of passive drive modes, such as a multiplex drive, may be sufficient.
　この表示装置１では、制御部４０は、液晶パネル２２における画像表示モードと外光反射モードとの切り替えを、透明電極基板２２Ａと透明電極基板２２Ｂとの間への直流電圧の印加により行い、または、透明電極基板２２Ａと透明電極基板２２Ｂとの間への１０Ｈｚ（ヘルツ）以下の交流電圧の印加により行うとよい。表示切替部２０の液晶パネル２２における画像表示モードと外光反射モードとの切り替え動作に要する消費電力を、より低減するのに有利だからである。 In the display device 1, the control unit 40 performs switching between the image display mode and the external light reflection mode in the liquid crystal panel 22 by applying a DC voltage between the transparent electrode substrate 22A and the transparent electrode substrate 22B, or It is good to carry out by applying an alternating voltage of 10 Hz (hertz) or less between the transparent electrode substrate 22A and the transparent electrode substrate 22B. This is because it is advantageous for further reducing the power consumption required for the switching operation between the image display mode and the external light reflection mode in the liquid crystal panel 22 of the display switching unit 20.
　また、液晶層２２Ｃは、０.３６μｍ以上０.５４μｍ未満のリターデーション値（Δｎ・ｄ）を有するとよい。液晶層２２ＣのΔｎ・ｄが上述の範囲内であることにより、表示部１０によって形成された表示画像の色付きを低減することができるとともに、表示画像をより明るくすることができるからである。また、リターデーション値が小さいことにより、表示画像の滲みも少なくなり、ある程度の広い視野角も確保することができる。 Further, the liquid crystal layer 22C may have a retardation value (Δn · d) of 0.36 μm or more and less than 0.54 μm. This is because, when Δn · d of the liquid crystal layer 22C is within the above-described range, coloring of the display image formed by the display unit 10 can be reduced and the display image can be brightened. In addition, since the retardation value is small, bleeding of the display image is reduced, and a certain wide viewing angle can be secured.
　また、液晶層２２Ｃの波長５５０ｎｍにおけるΔｎが０．０９以上０．１４未満であるとよい。これにより、鏡状態（外光反射モード）での透過特性、特に４００ｎｍから５００ｎｍの波長光における透過特性が向上するからである。 Further, Δn at a wavelength of 550 nm of the liquid crystal layer 22C is preferably 0.09 or more and less than 0.14. This is because the transmission characteristics in the mirror state (external light reflection mode), particularly the transmission characteristics in the wavelength range of 400 nm to 500 nm, are improved.
［表示装置１の動作］
　この表示装置１では、表示切替部２０における液晶パネル２２の液晶層２２Ｃに印加する電界の強度を制御したり、その電界の印加の有無を切り換えたりすることにより、表示切替部２０を透過状態（画面状態）としたり、表示切替部２０を鏡面状態としたりすることができる。 [Operation of Display Device 1]
In the display device 1, the display switching unit 20 is in a transmissive state (by controlling the strength of the electric field applied to the liquid crystal layer 22 </ b> C of the liquid crystal panel 22 in the display switching unit 20 or switching the presence / absence of application of the electric field. Screen state), and the display switching unit 20 can be in a mirror state.
　ここで、表示切替部２０の液晶パネル２２がＴＮ型液晶パネルであり、反射型偏光板２１の透過偏光軸と吸収型偏光板２３の透過偏光軸とが実質的に平行となるように配置されている場合の挙動について、図１および図２を参照して説明する。 Here, the liquid crystal panel 22 of the display switching unit 20 is a TN liquid crystal panel, and is arranged so that the transmission polarization axis of the reflective polarizing plate 21 and the transmission polarization axis of the absorption polarizing plate 23 are substantially parallel. The behavior of the case will be described with reference to FIG. 1 and FIG.
（液晶層２２Ｃに電界が印加されていない場合の挙動）
　液晶層２２Ｃに電界が印加されていない場合（図２の上段参照）、液晶層２２Ｃに含まれるネマチック液晶は９０度のツイスト状態にあり、基本的に９０度の旋光性を有する第１のモードとなる。このような状況下では、表示切替部２０に入射した外光Ｌ１は、吸収型偏光板２３を通過することによって吸収型偏光板２３の透過偏光軸２３Ｊと平行な振動面を有する第２の直線偏光Ｌｓになる。この第２の直線偏光Ｌｓはそののち液晶パネル２２を通過することにより吸収型偏光板２３の透過偏光軸２３Ｊと平行の振動面を有する第１の直線偏光Ｌｐに変換される。この第１の直線偏光Ｌｐはそののち反射型偏光板２１、吸収型偏光板１１、液晶パネル１３を順次そのまま透過して吸収型偏光板１４に入射する。第１の直線偏光Ｌｐは、吸収型偏光板１４の透過偏光軸１４Ｊと直交する振動面を有するので、吸収型偏光板１４により吸収される。 (Behavior when no electric field is applied to the liquid crystal layer 22C)
When an electric field is not applied to the liquid crystal layer 22C (see the upper part of FIG. 2), the nematic liquid crystal included in the liquid crystal layer 22C is in a twisted state of 90 degrees, and basically has a first mode of optical rotation of 90 degrees. It becomes. Under such circumstances, the external light L1 incident on the display switching unit 20 passes through the absorption-type polarizing plate 23 and thereby has a second straight line having a vibration plane parallel to the transmission polarization axis 23J of the absorption-type polarizing plate 23. The polarization becomes Ls. The second linearly polarized light Ls is then converted to the first linearly polarized light Lp having a vibration plane parallel to the transmission polarization axis 23J of the absorption polarizing plate 23 by passing through the liquid crystal panel 22. The first linearly polarized light Lp then passes through the reflective polarizing plate 21, the absorbing polarizing plate 11, and the liquid crystal panel 13 as they are, and enters the absorbing polarizing plate 14. Since the first linearly polarized light Lp has a vibration plane orthogonal to the transmission polarization axis 14J of the absorption polarizing plate 14, it is absorbed by the absorption polarizing plate 14.
　一方、表示部１０から出射する光（すなわち、表示部１０の表示画像を構成する画像光）Ｌ２は、吸収型偏光板１１によってその透過偏光軸１１Ｊと平行な振動面を有する第１の直線偏光Ｌｐとなっている。この第１の直線偏光Ｌｐは、反射型偏光板２１を透過し、液晶パネル２２に入射する。液晶パネル２２に入射した第１の直線偏光Ｌｐの振動面は液晶パネル２２を通過することにより９０度回転し、吸収型偏光板２３の透過偏光軸２３Ｊと平行な振動面を有する第２の直線偏光Ｌｓとなる。その第２の直線偏光Ｌｓはそのまま吸収型偏光板２３を透過して観察者に視認される（画面状態）。 On the other hand, the light L2 emitted from the display unit 10 (that is, the image light constituting the display image of the display unit 10) is a first linearly polarized light having a vibration plane parallel to the transmission polarization axis 11J by the absorption polarizing plate 11. Lp. The first linearly polarized light Lp passes through the reflective polarizing plate 21 and enters the liquid crystal panel 22. The vibration plane of the first linearly polarized light Lp incident on the liquid crystal panel 22 is rotated by 90 degrees by passing through the liquid crystal panel 22, and is a second straight line having a vibration plane parallel to the transmission polarization axis 23J of the absorption polarizing plate 23. The polarization becomes Ls. The second linearly polarized light Ls passes through the absorption polarizing plate 23 as it is and is visually recognized by the observer (screen state).
　このように、液晶層２２Ｃに電界が印加されていない場合においては、外光Ｌ１が観察者へ向けて反射されずに表示切替部２０を透過したのち吸収型偏光板１４により吸収され、また、表示部１０からの画像光Ｌ２が外部から視認できる状態となる。すなわち、表示装置１の表示画面は、画面状態（画像表示モード）となる。 Thus, in the case where an electric field is not applied to the liquid crystal layer 22C, the external light L1 is absorbed by the absorption polarizing plate 14 after passing through the display switching unit 20 without being reflected toward the viewer, The image light L2 from the display unit 10 is in a state visible from the outside. That is, the display screen of the display device 1 is in a screen state (image display mode).
（液晶層２２Ｃに電界が印加されている場合の挙動）
　次に、液晶層２２Ｃに所定のしきい値以上の電界が印加されている場合（図２の下段参照）の挙動について説明する。この場合、液晶層２２Ｃに含まれるネマチック液晶のツイスト状態は解消され、液晶パネル２２はその光軸方向に透過する光に対する旋光性を失い、第２のモードとなる。このような状況下では、表示切替部２０に入射した外光Ｌ１は、吸収型偏光板２３を通過することによって吸収型偏光板２３の透過偏光軸２３Ｊと平行な振動面を有する第２の直線偏光Ｌｓになる。この第２の直線偏光Ｌｓはそののち第１の直線偏光Ｌｐに変換されることなく液晶パネル２２をそのまま通過し、反射型偏光板２１に入射する。この第２の直線偏光Ｌｓは反射型偏光板２１の透過偏光軸２１Ｊと直交する方向の振動面を有するので、反射型偏光板２１において反射される。反射した第２の直線偏光Ｌｓは、再びそのまま液晶パネル２２と吸収型偏光板２３とを順次透過することにより観察者に視認される。 (Behavior when an electric field is applied to the liquid crystal layer 22C)
Next, the behavior when an electric field of a predetermined threshold value or higher is applied to the liquid crystal layer 22C (see the lower part of FIG. 2) will be described. In this case, the twisted state of the nematic liquid crystal contained in the liquid crystal layer 22C is eliminated, and the liquid crystal panel 22 loses optical rotation with respect to light transmitted in the optical axis direction, and enters the second mode. Under such circumstances, the external light L1 incident on the display switching unit 20 passes through the absorption-type polarizing plate 23 and thereby has a second straight line having a vibration plane parallel to the transmission polarization axis 23J of the absorption-type polarizing plate 23. The polarization becomes Ls. The second linearly polarized light Ls passes through the liquid crystal panel 22 as it is without being converted into the first linearly polarized light Lp and then enters the reflective polarizing plate 21. Since the second linearly polarized light Ls has a vibration surface in a direction perpendicular to the transmission polarization axis 21J of the reflective polarizing plate 21, it is reflected by the reflective polarizing plate 21. The reflected second linearly polarized light Ls passes through the liquid crystal panel 22 and the absorptive polarizing plate 23 in order again and is visually recognized by the observer.
　一方、表示部１０から出射された画像光Ｌ２は、吸収型偏光板１１の透過偏光軸１１Ｊと平行な振動面を有する第１の直線偏光Ｌｐであるから、反射型偏光板２１をそのまま透過して液晶パネル２２に入射する。その第１の直線偏光Ｌｐは、液晶パネル２２をそのまま通過したのち、吸収型偏光板２３に入射する。第１の直線偏光Ｌｐは、透過偏光軸２３Ｊと直交する振動面を有するので吸収型偏光板２３により吸収される。このため、表示部１０から出射された画像光は外部から視認されない。 On the other hand, the image light L2 emitted from the display unit 10 is the first linearly polarized light Lp having a vibration plane parallel to the transmission polarization axis 11J of the absorption polarizing plate 11, and thus passes through the reflection polarizing plate 21 as it is. Incident on the liquid crystal panel 22. The first linearly polarized light Lp passes through the liquid crystal panel 22 as it is and then enters the absorption polarizing plate 23. Since the first linearly polarized light Lp has a vibration plane orthogonal to the transmission polarization axis 23J, it is absorbed by the absorptive polarizing plate 23. For this reason, the image light emitted from the display unit 10 is not visually recognized from the outside.
　このように、液晶層２２Ｃに電界が印加されている場合においては、表示部１０からの画像光Ｌ２は外部から視認できず、また、外光Ｌ１が観察者へ向けて反射されるので、表示画面は鏡面状態（外光反射モード）となる。 As described above, when an electric field is applied to the liquid crystal layer 22C, the image light L2 from the display unit 10 cannot be visually recognized from the outside, and the external light L1 is reflected toward the observer. The screen is in a mirror state (external light reflection mode).
［表示装置１の作用効果］
　このように本実施の形態の表示装置１では、表示切替部２０において、反射型偏光板２１と吸収型偏光板２３とが直交ニコル配置に設定されると共に液晶パネル２２におけるＴＮ型液晶がいわゆるE-mode（Extraordinary-mode）で使用されるので、輝度および色度に関し優れた視野角特性が得られる。E-modeとは、液晶分子の長軸方向、すなわち異常光成分を用いるモードである。 [Operation and Effect of Display Device 1]
As described above, in the display device 1 of the present embodiment, the display switching unit 20 sets the reflective polarizing plate 21 and the absorbing polarizing plate 23 in a crossed Nicols arrangement, and the TN type liquid crystal in the liquid crystal panel 22 is so-called E. Since it is used in -mode (Extraordinary-mode), excellent viewing angle characteristics regarding luminance and chromaticity can be obtained. E-mode is a mode in which the long axis direction of liquid crystal molecules, that is, an abnormal light component is used.
　通常、表示部（液晶モニターなど）においては、ＴＮ型液晶はO-mode（Ordinary-mode）で使用される。O-modeとは、Ordinary-modeの略で、液晶分子の短軸方向、すなわち、常光成分を用いるモードである。電圧無印可時における輝度特性やコントラスト視野角の特性はE-modeのほうがよい。一方、電圧印加時の輝度特性およびコントラスト視野角の特性はO-modeのほうがよい。TN型液晶の場合は階調反転が起こりやすく黒～中間調の視野角を重視する必要があるため、表示部に用いられるＴＮ型液晶としては黒～中間調の特性のよいO-modeが広く使われていると考えられる。 Usually, TN type liquid crystal is used in O-mode (Ordinary-mode) in a display unit (liquid crystal monitor or the like). O-mode is an abbreviation for Ordinary-mode, which is a mode using the short axis direction of liquid crystal molecules, that is, an ordinary light component. E-mode is better for luminance characteristics and contrast viewing angle characteristics when no voltage is applied. On the other hand, the luminance characteristics and the contrast viewing angle characteristics during voltage application are better in O-mode. In the case of TN type liquid crystal, gradation inversion is likely to occur, and it is necessary to emphasize the viewing angle of black to halftone. Therefore, TN type liquid crystal used in the display section has a wide range of O-mode with good black to halftone characteristics. It is thought that it is used.
　しかしながら、ＴＮ型液晶を、画像表示モード（外光透過モード）と外光反射モードとの切り替えを行う表示切替部２０における液晶パネル２２に用いる場合には、E-modeで使用するとよい。O-modeで使用する場合と比較して、鏡面状態（外光反射モード）での輝度および色度に関する視野角特性は同等であり、画面状態（外光透過モード）での輝度および色度に関する視野角特性が向上するからである。 However, when the TN liquid crystal is used for the liquid crystal panel 22 in the display switching unit 20 that switches between the image display mode (external light transmission mode) and the external light reflection mode, it is preferable to use the TN type liquid crystal in the E-mode. Compared with the O-mode, the viewing angle characteristics related to brightness and chromaticity in the specular state (external light reflection mode) are equivalent, and the brightness and chromaticity in the screen state (external light transmission mode). This is because the viewing angle characteristics are improved.
　以下、E-modeのＴＮ型液晶を液晶パネル２２に用いた場合に画面状態（外光透過モード）での輝度および色度に関する視野角特性が向上する理由について説明する。 Hereinafter, the reason why viewing angle characteristics related to luminance and chromaticity in the screen state (external light transmission mode) are improved when an E-mode TN liquid crystal is used for the liquid crystal panel 22 will be described.
　ここでは、ＴＮ型液晶での偏光状態の変化が重要な要素となることが考えられるので、ポアンカレ球を用いて説明する。ポアンカレ球とは偏光状態の視覚的に表すことができる表現方法のひとつであり、球上のどの点に位置するかで偏光状態がわかるようになっている。ポアンカレ球では、例えば赤道上は直線偏光を表していて、経度はその方位を示している。また、緯度は楕円率を表しており、北極と南極で円偏光となっている。 Here, it is considered that the change of the polarization state in the TN type liquid crystal is an important factor, so the explanation will be made using the Poincare sphere. The Poincare sphere is one of the representation methods that can visually represent the polarization state, and the polarization state can be understood by the point on the sphere. In the Poincare sphere, for example, the equator represents linearly polarized light, and the longitude indicates the direction. Latitude expresses ellipticity and is circularly polarized in the north and south poles.
　図３Ａおよび図３Ｂは、O-modeおよびE-modeのそれぞれについて、赤色、緑色および青色の各光(波長４５０ｎｍ，５５０ｎｍ，６５０ｎｍの光）の入射角（極角）を変えた場合の、出射時の偏光状態を示したものである。ここでは、極角を０°から８０°まで変化させ、各光の入射する方位を４５°とし、Ｓ１－Ｓ２平面に切り出して考えることにする。これは、クロスニコルの場合、（Ｓ１，Ｓ２）＝（０，－１）および（Ｓ１，Ｓ２）＝（０，１）にそれぞれの偏光板の透過軸を表しているため、Ｓ２軸の高さを透過率として扱うことができるためである。図３Ａおよび図３Ｂとの比較から、O-modeのほうがE-modeよりも偏光状態の変化に対する角度依存性が大きいことがわかる。結果として、O-modeのほうがE-modeよりも波長依存性も大きくなり、斜め方向から見た際の色付きが大きくなるといえる。 3A and 3B show the output when the incident angles (polar angles) of red, green, and blue light (wavelengths of 450 nm, 550 nm, and 650 nm) are changed for each of O-mode and E-mode. It shows the polarization state at the time. Here, the polar angle is changed from 0 ° to 80 °, the direction in which each light is incident is 45 °, and it is cut out into the S1-S2 plane for consideration. In the case of crossed Nicols, the transmission axis of each polarizing plate is represented by (S1, S2) = (0, −1) and (S1, S2) = (0, 1). This is because the thickness can be treated as the transmittance. From comparison with FIG. 3A and FIG. 3B, it can be seen that the O-mode is more angularly dependent on the change in polarization state than the E-mode. As a result, O-mode is more wavelength-dependent than E-mode, and it can be said that coloring is increased when viewed from an oblique direction.
　次に、O-modeのほうがE-modeよりも角度依存性に対する感度が高い理由について考察する。図４Ａおよび図４Ｂに、O-modeおよびE-modeのそれぞれについて、極角６０°、方位４５°で入射した光の、液晶層での偏光状態の変化を示す。ここでは、Ｓ１－Ｓ３平面の断面で議論することとする。なぜなら、Ｓ１－Ｓ３平面で切ることで、Ｓ３方向の変化が偏光状態の楕円率を表しているので、液晶層で生じる位相差の変化を追うことができるからである。波長によって多少の差はあるが、共通していることは、実効的な入射偏光軸は偏光板を斜めから見た場合の角度（Δθ）だけずれた偏光軸となることがわかる。また、O-modeのほうがE-modeよりも、縦軸（Ｓ３）の変位量が大きいことがわかる。Ｓ３軸は楕円率の変化を表すことから、位相差の感度に差があるということを示している。 Next, consider why O-mode is more sensitive to angular dependence than E-mode. 4A and 4B show changes in the polarization state in the liquid crystal layer of light incident at a polar angle of 60 ° and an azimuth of 45 ° for each of O-mode and E-mode. Here, the discussion will be made on the cross section of the S1-S3 plane. This is because, by cutting along the S1-S3 plane, the change in the S3 direction represents the ellipticity of the polarization state, so that the change in the phase difference occurring in the liquid crystal layer can be followed. Although there are some differences depending on the wavelength, what is common is that the effective incident polarization axis is a polarization axis shifted by an angle (Δθ) when the polarizing plate is viewed obliquely. It can also be seen that the displacement amount of the vertical axis (S3) is larger in O-mode than in E-mode. Since the S3 axis represents the change in ellipticity, it indicates that there is a difference in the sensitivity of the phase difference.
　この差が生じる理由を説明するために、図５Ａおよび図５Ｂに、O-modeおよびE-modeのそれぞれについてＴＮ型液晶における液晶配向軸と偏光板の透過軸との関係の概略を示す。E-modeの場合、実効的な偏光板の透過軸と液晶分子の遅相軸は常に一致しているため、位相差は生じにくい。一方、O-modeの場合、液晶分子の遅相軸は、９０°＋Δθとなる。これは、偏光軸と遅相軸がΔθだけずれているということは、位相差がより生じやすいということを表している。その結果、液晶の各層を通過するごとの楕円率の変化量が大きくなり、結果として、波長依存性も増大し、色づきやすくなると考えられる。 In order to explain the reason why this difference occurs, FIGS. 5A and 5B schematically show the relationship between the liquid crystal alignment axis in the TN liquid crystal and the transmission axis of the polarizing plate for each of O-mode and E-mode. In the case of E-mode, since the effective transmission axis of the polarizing plate and the slow axis of the liquid crystal molecules always coincide with each other, a phase difference hardly occurs. On the other hand, in the O-mode, the slow axis of the liquid crystal molecules is 90 ° + Δθ. This means that the fact that the polarization axis and the slow axis are displaced by Δθ means that a phase difference is more likely to occur. As a result, the amount of change in ellipticity every time it passes through each layer of the liquid crystal is increased, and as a result, the wavelength dependency is also increased, and it is considered that coloring is facilitated.
　以上の理由から、画像表示モード（外光透過モード）と外光反射モードとの切り替えを行う液晶パネル２２に用いるＴＮ型液晶としてはE-modeが好ましいといえる。 For the above reasons, it can be said that E-mode is preferable as the TN liquid crystal used in the liquid crystal panel 22 for switching between the image display mode (external light transmission mode) and the external light reflection mode.
　また、本実施の形態では、液晶パネル２２における画像表示モードと外光反射モードとの切替動作を行う際、制御部４０は、透明電極基板２２Ａと透明電極基板２２Ｂとの間に印加する直流電圧または交流電圧の増減速度を変化させるように切替駆動部３０を制御するとよい。透明電極基板２２Ａ，２２Ｂの有する抵抗に起因する動作遅延（画面内の位置による動作のずれ）を緩和することができるからである。図６Ａは、透明電極基板２２Ａと透明電極基板２２Ｂとの間に印加される電圧の変化を表した特性図である。図６Ａにおいて、実線のグラフは、透明電極基板２２Ａ，２２Ｂと切替駆動部３０からの配線との接続部近傍（例えば図１の透明電極基板２２Ａ，２２Ｂの左端近傍）の位置Ｐ１での電圧変化を表す。一方、破線のグラフは、透明電極基板２２Ａ，２２Ｂと切替駆動部３０からの配線との接続部と反対側の端部近傍（例えば図１の透明電極基板２２Ａ，２２Ｂの右端近傍）の位置Ｐ２での電圧変化を表す。図６Ａに示したように、時間の経過に対し一定の割合で電圧を徐々に増加させ、あるいは、時間の経過に対し一定の割合で電圧を徐々に減少させることにより、実線のグラフと破線のグラフとのずれを小さく抑えることができる。すなわち、位置Ｐ１での切り替え動作と位置Ｐ２での切り替え動作との間の時差（位置Ｐ１と位置Ｐ２との間で生じる動作遅延）を低減できる。 In the present embodiment, when the switching operation between the image display mode and the external light reflection mode in the liquid crystal panel 22 is performed, the control unit 40 applies the DC voltage applied between the transparent electrode substrate 22A and the transparent electrode substrate 22B. Or it is good to control the switching drive part 30 so that the increase / decrease speed of an alternating voltage may be changed. This is because an operation delay due to the resistance of the transparent electrode substrates 22A and 22B (operational deviation due to the position in the screen) can be reduced. FIG. 6A is a characteristic diagram showing a change in voltage applied between the transparent electrode substrate 22A and the transparent electrode substrate 22B. In FIG. 6A, a solid line graph indicates a voltage change at a position P1 in the vicinity of the connection portion between the transparent electrode substrates 22A and 22B and the wiring from the switching drive unit 30 (for example, near the left end of the transparent electrode substrates 22A and 22B in FIG. 1). Represents. On the other hand, the broken line graph indicates a position P2 in the vicinity of the end opposite to the connection portion between the transparent electrode substrates 22A and 22B and the wiring from the switching drive unit 30 (for example, near the right end of the transparent electrode substrates 22A and 22B in FIG. This represents the voltage change at. As shown in FIG. 6A, by gradually increasing the voltage at a constant rate over time, or gradually decreasing the voltage at a constant rate over time, a solid line graph and a broken line Deviation from the graph can be kept small. In other words, the time difference between the switching operation at the position P1 and the switching operation at the position P2 (operation delay occurring between the position P1 and the position P2) can be reduced.
　なお、図６Ａでは、電圧の増加および減少を各々一定の割合で行うようにしたが、例えば図６Ｂに示したように電圧の増加および減少を段階的に（多段的に）行うようにしてもよい。 In FIG. 6A, the voltage increase and decrease are each performed at a constant rate. However, for example, as illustrated in FIG. 6B, the voltage increase and decrease may be performed step by step (multiple steps). Good.
　一方、例えば図７Ａおよび図７Ｂに示したように、電圧変化の波形が矩形状をなすようにした場合、すなわち、透明電極基板２２Ａと透明電極基板２２Ｂとの間に印加する直流電圧または交流電圧を瞬間的に変化させるようにした場合、位置Ｐ１での電圧変化（実線のグラフ）に対し位置Ｐ２での電圧変化（破線のグラフ）が比較的大きく遅延することとなる。なお、図７Ａは、画像表示モードと外光反射モードとの切り替え動作に要する所定の電圧に至るまで１ステップの電圧印加を行った場合を例示し、図７Ｂは、画像表示モードと外光反射モードとの切り替え動作に要する所定の電圧に至るまで２ステップの電圧印加を行った場合を例示している。 On the other hand, for example, as shown in FIGS. 7A and 7B, when the voltage change waveform is rectangular, that is, a DC voltage or an AC voltage applied between the transparent electrode substrate 22A and the transparent electrode substrate 22B. Is instantaneously changed, the voltage change at the position P2 (broken line graph) is relatively delayed with respect to the voltage change at the position P1 (solid line graph). FIG. 7A illustrates the case where voltage application of one step is performed until reaching a predetermined voltage required for the switching operation between the image display mode and the external light reflection mode, and FIG. 7B illustrates the image display mode and the external light reflection. A case where voltage application in two steps is performed until reaching a predetermined voltage required for the mode switching operation is illustrated.
　また、本実施の形態の表示装置１では、液晶パネル２２の液晶層２２Ｃが０.３６μｍ以上０.５４μｍ未満のΔｎ・ｄを有するようにすれば、表示部１０によって形成された表示画像の色付きを低減することができるとともに、その表示画像をより明るくすることができる。また、表示画像の滲みも少なくなり、ある程度の広い視野角も確保することができる。 Further, in the display device 1 according to the present embodiment, if the liquid crystal layer 22C of the liquid crystal panel 22 has Δn · d of 0.36 μm or more and less than 0.54 μm, the colored display image formed by the display unit 10 is colored. Can be reduced, and the display image can be brightened. In addition, the blur of the display image is reduced, and a wide viewing angle can be secured to some extent.
　また、液晶層２２Ｃの波長５５０ｎｍにおけるΔｎを０．０９以上０．１４未満とすれば、鏡面状態での透過特性、特に４００ｎｍから５００ｎｍの波長光における透過特性を向上させることができる。 Further, if Δn at a wavelength of 550 nm of the liquid crystal layer 22C is set to 0.09 or more and less than 0.14, it is possible to improve the transmission characteristics in the mirror surface state, particularly the transmission characteristics in the wavelength range of 400 nm to 500 nm.
＜２．適用例（電子機器）＞
　次に、図８を参照して、表示装置１を備えた電子機器１００について説明する。図８は、電子機器１００の全体構成を表す概略図である。 <2. Application example (electronic equipment)>
Next, with reference to FIG. 8, the electronic device 100 including the display device 1 will be described. FIG. 8 is a schematic diagram illustrating the overall configuration of the electronic device 100.
　電子機器１００は、上記第１の実施形態の表示装置１を備えたものである。図８は、電子機器１００の内部に配置される表示装置１００の表示制御系を模式的に示すブロック図である。電子機器１００は、表示装置１のほか、表示駆動部１３Ｘと照明駆動部１５Ｘとを備えている。電子機器１００では、制御部４０が、切替部２０を駆動する切替駆動部３０の制御を行うほか、表示駆動部１３Ｘおよび照明駆動部１５Ｘの制御をも行う。上記の各構成要素は、全て表示装置１の内部に設置されていてもよいし、表示装置１の外部、すなわち電子機器１００の内部における表示装置１以外の領域に設置されていてもよいし、あるいは、一部の構成要素が表示装置１の内部に設置され、他の構成要素が表示装置１以外の電子機器１００の内部に設置されていてもよい。 The electronic device 100 includes the display device 1 according to the first embodiment. FIG. 8 is a block diagram schematically showing a display control system of the display device 100 arranged inside the electronic device 100. In addition to the display device 1, the electronic device 100 includes a display drive unit 13X and an illumination drive unit 15X. In the electronic device 100, the control unit 40 controls the switching drive unit 30 that drives the switching unit 20, and also controls the display drive unit 13X and the illumination drive unit 15X. Each of the above components may be installed inside the display device 1, or may be installed outside the display device 1, that is, in an area other than the display device 1 inside the electronic device 100, Alternatively, some components may be installed inside the display device 1, and other components may be installed inside the electronic device 100 other than the display device 1.
　表示駆動部１３Ｘは、表示装置１の表示部１０に設けられた液晶パネル１３を駆動するものである。表示駆動部１３Ｘは、液晶パネル１３の液晶駆動領域内に構成された複数の画素領域をそれぞれ駆動するための駆動電圧を供給するものであり、例えば、マルチプレックス駆動方式やアクティブ駆動方式では、走査信号、およびこの走査信号に対応するデータ信号を、液晶パネル１３のコモン端子（走査線端子）およびセグメント端子（データ線端子）にそれぞれ同期させて供給する。画像データ等の表示データは電子機器１００のメイン回路から制御部１００Ｘを介してこの表示駆動部１３Ｘに送られる。 The display driving unit 13X drives the liquid crystal panel 13 provided in the display unit 10 of the display device 1. The display drive unit 13X supplies drive voltages for driving a plurality of pixel regions configured in the liquid crystal drive region of the liquid crystal panel 13, and for example, in the multiplex drive method and the active drive method, scanning is performed. A signal and a data signal corresponding to the scanning signal are supplied in synchronization with the common terminal (scanning line terminal) and the segment terminal (data line terminal) of the liquid crystal panel 13, respectively. Display data such as image data is sent from the main circuit of the electronic device 100 to the display driving unit 13X via the control unit 100X.
　照明駆動部１５Ｘは、表示部１０のバックライト１５を駆動するものである。より具体的には、照明駆動部１５Ｘは、バックライト１５への電力供給を制御し、例えば、バックライト１５の点灯状態と消灯状態とを切り換えるように機能する。 The illumination driving unit 15X drives the backlight 15 of the display unit 10. More specifically, the illumination drive unit 15X functions to control power supply to the backlight 15 and to switch between a lighting state and a light-off state of the backlight 15, for example.
　制御部４０は、表示駆動部１３Ｘ、照明駆動部１５Ｘおよび切替駆動部３０をそれぞれ制御し、それら各部に対する制御指令やデータ送出などを行う。例えば、表示切替部２０を画像表示モードにして表示装置１を画面状態にする場合には、表示駆動部１３Ｘにより液晶パネル１３を駆動して画像表示を行うと同時に、切替駆動部３０によって液晶パネル２２を制御することで表示切替部２０を透過状態とする。一方、表示切替部２０を外光反射モードにして表示装置１を鏡面状態にする場合には、切替駆動部３０によって液晶パネル２２を制御することで表示切替部２０を外光反射モードとすると同時に、表示駆動部１３Ｘにより液晶パネル１３を全遮断状態（シャッタ閉鎖状態）にするか、あるいは照明駆動部１５Ｘによりバックライト１５を消灯する。 The control unit 40 controls the display driving unit 13X, the illumination driving unit 15X, and the switching driving unit 30, respectively, and performs control commands and data transmission to the respective units. For example, when the display switching unit 20 is set to the image display mode and the display device 1 is in the screen state, the display driving unit 13X drives the liquid crystal panel 13 to display an image, and at the same time, the switching driving unit 30 performs the liquid crystal panel display. By controlling 22, the display switching unit 20 is brought into a transmissive state. On the other hand, when the display switching unit 20 is set to the external light reflection mode and the display device 1 is set to the mirror state, the display switching unit 20 is set to the external light reflection mode by controlling the liquid crystal panel 22 by the switching drive unit 30. Then, the liquid crystal panel 13 is brought into a completely blocked state (shutter closed state) by the display driving unit 13X, or the backlight 15 is turned off by the illumination driving unit 15X.
　このように、本開示の電子機器１００によれば、上記の表示装置１を備えるようにしたので、観察者に視認される表示画像および反射像における視野角特性を向上させることができる。このため、電子機器１００によれば、画面状態（画像表示モード）および鏡面状態（外光反射モード）のいずれにおいても優れた表示性能を発揮することができる。 As described above, according to the electronic device 100 of the present disclosure, since the display device 1 is provided, it is possible to improve the viewing angle characteristics in the display image and the reflected image visually recognized by the observer. For this reason, according to the electronic device 100, excellent display performance can be exhibited both in the screen state (image display mode) and in the mirror surface state (external light reflection mode).
　電子機器１００としては、例えばテレビジョン装置，デジタルカメラ，ノート型パーソナルコンピュータ、携帯電話、スマートフォン、タブレット端末装置等の携帯端末装置あるいはビデオカメラ等が挙げられる。言い換えると、上記表示装置は、外部から入力された映像信号あるいは内部で生成した映像信号を、画像あるいは映像として表示するあらゆる分野の電子機器に適用することが可能である。 Examples of the electronic device 100 include a television device, a digital camera, a notebook personal computer, a mobile terminal device such as a mobile phone, a smartphone, and a tablet terminal device, or a video camera. In other words, the display device can be applied to electronic devices in various fields that display a video signal input from the outside or a video signal generated inside as an image or video.
＜３．実験例＞
［実験例１］
（実験例１－１）
　上記実施の形態に係る表示装置１において、表示切替部２０が透過状態にある場合および鏡面状態にある場合の光学特性についてシミュレーションを実施した。それらの結果を図９Ａ（透過状態）および図９Ｂ（鏡面状態）に示す。なお、本シミュレーションに用いた液晶配向に関する設定値を表１に示す。 <3. Experimental example>
[Experimental Example 1]
(Experimental example 1-1)
In the display device 1 according to the above-described embodiment, simulation was performed on optical characteristics when the display switching unit 20 is in the transmissive state and in the mirror state. The results are shown in FIG. 9A (transmission state) and FIG. 9B (mirror surface state). Table 1 shows the set values for the liquid crystal alignment used in this simulation.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
（実験例１－２）
　表示切替部２０の液晶パネル２２におけるＴＮ型液晶をいわゆるO-modeとしたことを除き、他は上記実験例１－１と同様にしてシミュレーションを実施した。それらの結果を図１０Ａ（透過状態）および図１０Ｂ（鏡面状態）に示す。 (Experimental example 1-2)
A simulation was performed in the same manner as in Experimental Example 1-1 except that the TN type liquid crystal in the liquid crystal panel 22 of the display switching unit 20 was set to a so-called O-mode. The results are shown in FIG. 10A (transmission state) and FIG. 10B (mirror surface state).
　その結果、図９Ａと図１０Ａとの比較から、透過状態での特性についてはE-mode（図９Ａ）のほうがO-mode（図１０Ａ）よりも輝度および色度ずれの視野角依存が少ないことが確認された。その一方、図９Ｂと図１０Ｂとの比較により、鏡面状態での特性には両者（E-modeおよぼO-mode）にはほとんど差異が無いことも確認された。 As a result, from the comparison between FIG. 9A and FIG. 10A, regarding the characteristics in the transmissive state, the E-mode (FIG. 9A) is less dependent on the viewing angle of luminance and chromaticity deviation than the O-mode (FIG. 10A). Was confirmed. On the other hand, a comparison between FIG. 9B and FIG. 10B also confirmed that there was almost no difference between the two characteristics (E-mode and O-mode).
　一般的には、ＰＣ用モニタをはじめとするＴＮ型液晶はO-modeで使用される。電圧印加時の輝度特性およびコントラスト視野角特性がO-modeのほうがよいからである。すなわち、通常の液晶ディスプレイとしての使い方をする場合は、黒～中間調(電圧印加時)での輝度特性およびコントラスト視野角特性はO-modeのほうがE-modeよりも良好であり、白(電圧無印加時)での輝度特性およびコントラスト視野角特性はO-modeよりもE-modeのほうが良好である。また、黒～中間調状態の画質のほうが白状態の画質よりも優先される。ここで、ＴＮ型液晶では階調反転が起こりやすいので、黒～中間調の視野角を重視する必要がある。よって、黒～中間調での輝度特性およびコントラスト視野角特性の良好なO-modeが広く使われていると思われる。 Generally, TN type liquid crystal including PC monitor is used in O-mode. This is because the O-mode is better in luminance characteristics and contrast viewing angle characteristics when a voltage is applied. In other words, when using as a normal liquid crystal display, the luminance characteristics and contrast viewing angle characteristics in black to halftone (when voltage is applied) are better in O-mode than in E-mode, and white (voltage E-mode is better than O-mode in luminance characteristics and contrast viewing angle characteristics when no voltage is applied. Also, the image quality in the black to halftone state has priority over the image quality in the white state. Here, since TN type liquid crystal tends to cause gradation inversion, it is necessary to emphasize the viewing angle of black to halftone. Therefore, it seems that O-mode with good luminance characteristics and contrast viewing angle characteristics from black to halftone is widely used.
　ところがＴＮ型液晶を表示装置１における表示切替部２０に用いる場合、上述したようにE-modeで使用することが望ましい。この理由は以下のように考えられる。表示切替部２０において鏡面状態となる電圧印加状態では、図２の下段に示したように、外光Ｌ１が、吸収型偏光板２３と液晶層２２Ｃを含む液晶パネル２２とを順次通過し反射型偏光板２１において反射する。反射型偏光板２１において反射した光はもう一度液晶層２２Ｃを含む液晶パネル２２を通過したのち、最表面の吸収型偏光板２３を透過して外部に至る。したがって実効的には液晶層を２つ重ね合わせた場合と同等の視野角特性が得られることになる。その結果、通常の液晶ディスプレイとしての使い方をした場合における、電圧印加時でのE-mode に対するO-modeの優位性がほとんどなくなる。すなわち、表示切替部２０に用いる場合には、電圧印加時ではO-modeとE-modeとの差異がほとんどなく、透過状態(電圧無印加時)では輝度特性およびコントラスト視野角特性においてE-modeのほうがO-modeよりも良好である。さらに、透過状態での画質のほうが鏡面状態での画質よりも優先されると考えられる。よって、表示切替部２０に用いられるＴＮ型液晶はE-modeであるといえる。 However, when the TN liquid crystal is used for the display switching unit 20 in the display device 1, it is desirable to use it in E-mode as described above. The reason is considered as follows. In the voltage application state in the mirror state in the display switching unit 20, as shown in the lower part of FIG. 2, the external light L1 sequentially passes through the absorption polarizing plate 23 and the liquid crystal panel 22 including the liquid crystal layer 22C to reflect. Reflected by the polarizing plate 21. The light reflected by the reflective polarizing plate 21 once again passes through the liquid crystal panel 22 including the liquid crystal layer 22C, and then passes through the outermost absorption polarizing plate 23 to reach the outside. Therefore, the viewing angle characteristic equivalent to the case where two liquid crystal layers are superposed is effectively obtained. As a result, when using as a normal liquid crystal display, the superiority of O-mode over E-mode at the time of voltage application is almost lost. That is, when used in the display switching unit 20, there is almost no difference between the O-mode and the E-mode when a voltage is applied, and the E-mode in the luminance characteristic and the contrast viewing angle characteristic in the transmission state (when no voltage is applied). Is better than O-mode. Furthermore, it is considered that the image quality in the transmissive state has priority over the image quality in the mirror surface state. Therefore, it can be said that the TN liquid crystal used in the display switching unit 20 is in E-mode.
（実験例２－１）
　次に、上記実施の形態に係る表示装置１のサンプルを実際に作製し、そのサンプルについて透過状態（画面状態）での色度に関する視野角特性を測定した。なお、輝度および色度測定にはＥＬＤＩＭ社製のＥｚ－Ｃｏｎｔｒａｓｔを用い、０°（水平）方位と４５°方位での色度の視野角依存性を調べた。それらの結果を図１１Ａ（０°方位）および図１１Ｂ（４５°方位）に示す。図１１Ａにおいて、横軸が極角（－８０°～０°～８０°）を表し、縦軸が色差Δu'v'の差分ΔΔu'v'を表す。 (Experimental example 2-1)
Next, a sample of the display device 1 according to the above-described embodiment was actually manufactured, and the viewing angle characteristic regarding the chromaticity in the transmission state (screen state) was measured for the sample. For luminance and chromaticity measurement, Ez-Contrast manufactured by ELDIM was used, and the viewing angle dependence of chromaticity at 0 ° (horizontal) azimuth and 45 ° azimuth was examined. The results are shown in FIG. 11A (0 ° azimuth) and FIG. 11B (45 ° azimuth). In FIG. 11A, the horizontal axis represents the polar angle (−80 ° to 0 ° to 80 °), and the vertical axis represents the difference ΔΔu′v ′ of the color difference Δu′v ′.
（実験例２－２）
　表示切替部２０の液晶パネル２２におけるＴＮ型液晶をいわゆるO-modeとしたことを除き、他は上記実験例２－１と同様にしてサンプルを作製し、同様の調査を行った。それらの結果を図１１Ａ（０°方位）および図１１Ｂ（４５°方位）に併せて示す。 (Experimental example 2-2)
Except that the TN type liquid crystal in the liquid crystal panel 22 of the display switching unit 20 is a so-called O-mode, a sample was prepared in the same manner as in Experimental Example 2-1, and the same investigation was performed. The results are also shown in FIG. 11A (0 ° azimuth) and FIG. 11B (45 ° azimuth).
　図１１Ａに示したように０°方位ではO-modeとE-modeとの差異がほとんどなかったものの、図１１Ｂに示したように４５°方位ではE-modeのほうがO-modeよりも色度変化が抑えられていることが確認できた。すなわち、実験例１－１，１－２に示したシミュレーションの結果とも一致する結果となった。 As shown in FIG. 11A, there was almost no difference between O-mode and E-mode at 0 ° azimuth, but at 45 ° azimuth, E-mode was more chromaticity than O-mode as shown in FIG. 11B. It was confirmed that the change was suppressed. That is, the results coincided with the simulation results shown in Experimental Examples 1-1 and 1-2.
（実験例３）
　上記実施の形態に係る表示装置１において、表示切替部２０に対する印加電圧（交流電圧）と反射率との関係についてシミュレーションを実施した。その結果を図１２に示す。また、表示切替部２０に対する印加電圧（交流電圧）と周波数（Ｎｚ）と消費電力（Ｗ）との関係について表２に示す。 (Experimental example 3)
In the display device 1 according to the above-described embodiment, a simulation was performed on the relationship between the applied voltage (AC voltage) to the display switching unit 20 and the reflectance. The result is shown in FIG. Table 2 shows the relationship among the applied voltage (AC voltage), frequency (Nz), and power consumption (W) applied to the display switching unit 20.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　図１２に示したように、安定した鏡面状態（例えば反射率の変動が０．２％以下の状態）とするには印加電圧を５Ｖ以上とすることが望ましいことがわかった。また、表２に示したように、周波数を１０Ｈｚ以下とすることで、待機時の表示装置に求められる０．５Ｗ（ワット）の消費電力の半分未満の消費電力を実現することができることが確認できた。 As shown in FIG. 12, it was found that the applied voltage is desirably 5 V or more in order to obtain a stable mirror surface state (for example, a state in which the reflectance fluctuation is 0.2% or less). In addition, as shown in Table 2, it is confirmed that by setting the frequency to 10 Hz or less, it is possible to realize power consumption less than half of the power consumption of 0.5 W (watt) required for the display device during standby. did it.
　以上、実施の形態および実験例を挙げて本開示を説明したが、本開示は上記実施の形態等に限定されるものではなく、種々の変形が可能である。例えば、上記実施の形態等では表示装置１や電子機器１００の構成を具体的に挙げて説明したが、全ての構成要素を備える必要はなく、また、他の構成要素を備えていてもよい。 As described above, the present disclosure has been described with the embodiment and the experimental example, but the present disclosure is not limited to the above-described embodiment and the like, and various modifications are possible. For example, in the above-described embodiment and the like, the configuration of the display device 1 and the electronic device 100 has been specifically described, but it is not necessary to include all the components, and other components may be included.
　なお、本明細書中に記載された効果はあくまで例示であってその記載に限定されるものではなく、他の効果があってもよい。また、本技術は以下のような構成を取り得るものである。
（１）
　第１の偏光軸を有する第１の直線偏光を透過すると共に前記第１の偏光軸と交差する第２の偏光軸を有する第２の直線偏光を反射する反射型偏光部材と、
　前記第１の偏光軸に沿って配向する液晶分子を含むＴＮ（Twisted Nematic）型液晶層、および前記ＴＮ型液晶層を挟んで対向する１対の透明電極を有する液晶パネルと、
　前記第１の直線偏光を吸収すると共に前記第２の直線偏光を透過させる吸収型偏光部材と
　を順に有する光学装置。
（２）
　前記液晶パネルは、前記第１の直線偏光を前記第２の直線偏光へ変換して透過させる第１のモードと、前記第１の直線偏光を前記第２の直線偏光へ変換せずに透過させる第２のモードとの切り替えを行うものである
　上記（１）記載の光学装置。
（３）
　制御部をさらに有し、
　前記制御部は、前記液晶パネルにおける前記第１のモードと前記第２のモードとの切り替えを、前記１対の透明電極間への直流電圧の印加、または前記１対の透明電極間への１０Ｈｚ（ヘルツ）以下の交流電圧の印加により行う
　上記（２）記載の光学装置。
（４）
　前記制御部は、前記直流電圧の増減速度または前記交流電圧の増減速度を変化させる
　上記（３）記載の光学装置。
（５）
　前記ＴＮ型液晶層は、０.３６μｍ以上０.５４μｍ未満のΔｎ・ｄを有する
　上記（１）から（４）のいずれか１つに記載の光学装置。
（６）
　前記ＴＮ型液晶層の波長５５０ｎｍにおけるΔｎが０．０９以上０．１４未満である
　上記（５）記載の光学装置。
（７）
　前記液晶分子は、５°以下のプレチルト角を有する
　上記（１）から（６）のいずれか１つに記載の光学装置。
（８）
　画像光として第１の偏光軸を有する第１の直線偏光を出射する表示部と、
　前記表示部と対向して配置され、前記第１の直線偏光を透過する画像表示モードと外光を反射する外光反射モードとの切り替えを行う表示切替部と
　を備え、
　前記表示部は、前記第１の直線偏光を透過すると共に前記第１の偏光軸と交差する第２の偏光軸を有する第２の直線偏光を吸収する第１の吸収型偏光部材を有し、
　前記表示切替部は、
　前記第１の直線偏光を透過すると共に前記第２の直線偏光を反射する反射型偏光部材と、
　前記第１の偏光軸に沿って配向する液晶分子を含むＴＮ（Twisted Nematic）型液晶層、および前記ＴＮ型液晶層を挟んで対向する１対の透明電極を有する液晶パネルと、
　前記第１の直線偏光を吸収すると共に前記第２の直線偏光を透過させる第２の吸収型偏光部材と
　を前記表示部の近くから遠ざかる方向に順に有する
　表示装置。
（９）
　前記表示部は、液晶表示素子または有機発光素子を含む
　上記（８）記載の表示装置。
（１０）
　表示装置と、
　前記表示装置を制御する制御部と
　を備え、
　前記表示装置は、
　画像光として第１の偏光軸を有する第１の直線偏光を出射する表示部と、
　前記表示部と対向して配置され、前記第１の直線偏光を透過する画像表示モードと外光を反射する外光反射モードとの切り替えを行う表示切替部と
　を備え、
　前記表示部は、前記第１の直線偏光を透過すると共に前記第１の偏光軸と交差する第２の偏光軸を有する第２の直線偏光を吸収する第１の吸収型偏光部材を有し、
　前記表示切替部は、
　前記第１の直線偏光を透過すると共に前記第２の直線偏光を反射する反射型偏光部材と、
　前記第１の偏光軸に沿って配向する液晶分子を含むＴＮ（Twisted Nematic）型液晶層、および前記ＴＮ型液晶層を挟んで対向する１対の透明電極を有する液晶パネルと、
　前記第１の直線偏光を吸収すると共に前記第２の直線偏光を透過させる第２の吸収型偏光部材と
　を前記表示部の近くから遠ざかる方向に順に有する
　電子機器。 In addition, the effect described in this specification is an illustration to the last, and is not limited to the description, There may exist another effect. Moreover, this technique can take the following structures.
(1)
A reflective polarizing member that transmits a first linearly polarized light having a first polarization axis and reflects a second linearly polarized light having a second polarization axis that intersects the first polarization axis;
A TN (Twisted Nematic) type liquid crystal layer containing liquid crystal molecules aligned along the first polarization axis, and a liquid crystal panel having a pair of transparent electrodes facing each other with the TN type liquid crystal layer interposed therebetween;
An optical polarization device that sequentially absorbs the first linearly polarized light and transmits the second linearly polarized light.
(2)
The liquid crystal panel converts the first linearly polarized light into the second linearly polarized light and transmits the first linearly polarized light, and transmits the first linearly polarized light without converting it into the second linearly polarized light. The optical device according to (1), wherein the optical device is switched to a second mode.
(3)
A control unit;
The control unit switches between the first mode and the second mode in the liquid crystal panel, applies a DC voltage between the pair of transparent electrodes, or 10 Hz between the pair of transparent electrodes. (Hertz) The optical device according to (2), which is performed by applying the following AC voltage.
(4)
The said control part changes the increase / decrease speed of the said DC voltage, or the increase / decrease speed of the said AC voltage. The optical apparatus of said (3) description.
(5)
The optical device according to any one of (1) to (4), wherein the TN liquid crystal layer has Δn · d of 0.36 μm or more and less than 0.54 μm.
(6)
The optical device according to (5), wherein Δn of the TN liquid crystal layer at a wavelength of 550 nm is 0.09 or more and less than 0.14.
(7)
The optical device according to any one of (1) to (6), wherein the liquid crystal molecules have a pretilt angle of 5 ° or less.
(8)
A display that emits first linearly polarized light having a first polarization axis as image light;
A display switching unit that is disposed to face the display unit and performs switching between an image display mode that transmits the first linearly polarized light and an external light reflection mode that reflects external light, and
The display unit includes a first absorptive polarizing member that transmits the first linearly polarized light and absorbs the second linearly polarized light having a second polarization axis that intersects the first polarization axis,
The display switching unit
A reflective polarizing member that transmits the first linearly polarized light and reflects the second linearly polarized light;
A TN (Twisted Nematic) type liquid crystal layer containing liquid crystal molecules aligned along the first polarization axis, and a liquid crystal panel having a pair of transparent electrodes facing each other with the TN type liquid crystal layer interposed therebetween;
A display device comprising: a second absorptive polarizing member that absorbs the first linearly polarized light and transmits the second linearly polarized light in a direction away from the vicinity of the display unit.
(9)
The display device according to (8), wherein the display unit includes a liquid crystal display element or an organic light emitting element.
(10)
A display device;
A control unit for controlling the display device,
The display device
A display that emits first linearly polarized light having a first polarization axis as image light;
A display switching unit that is disposed to face the display unit and performs switching between an image display mode that transmits the first linearly polarized light and an external light reflection mode that reflects external light, and
The display unit includes a first absorptive polarizing member that transmits the first linearly polarized light and absorbs the second linearly polarized light having a second polarization axis that intersects the first polarization axis,
The display switching unit
A reflective polarizing member that transmits the first linearly polarized light and reflects the second linearly polarized light;
A TN (Twisted Nematic) type liquid crystal layer containing liquid crystal molecules aligned along the first polarization axis, and a liquid crystal panel having a pair of transparent electrodes facing each other with the TN type liquid crystal layer interposed therebetween;
An electronic apparatus comprising: a second absorptive polarizing member that absorbs the first linearly polarized light and transmits the second linearly polarized light in a direction away from the vicinity of the display unit.
　本出願は、日本国特許庁において２０１５年８月３１日に出願された日本特許出願番号２０１５－１７１０８０号を基礎として優先権を主張するものであり、この出願のすべての内容を参照によって本出願に援用する。 This application claims priority on the basis of Japanese Patent Application No. 2015-171080 filed on August 31, 2015 at the Japan Patent Office. The entire contents of this application are hereby incorporated by reference. Incorporated into.
　当業者であれば、設計上の要件や他の要因に応じて、種々の修正、コンビネーション、サブコンビネーション、および変更を想到し得るが、それらは添付の請求の範囲やその均等物の範囲に含まれるものであることが理解される。 Those skilled in the art will envision various modifications, combinations, subcombinations, and changes, depending on design requirements and other factors, which are within the scope of the appended claims and their equivalents. It is understood that

Claims (10)

  1. 　第１の偏光軸を有する第１の直線偏光を透過すると共に前記第１の偏光軸と交差する第２の偏光軸を有する第２の直線偏光を反射する反射型偏光部材と、
    　前記第１の偏光軸に沿って配向する液晶分子を含むＴＮ（Twisted Nematic）型液晶層、および前記ＴＮ型液晶層を挟んで対向する１対の透明電極を有する液晶パネルと、
    　前記第１の直線偏光を吸収すると共に前記第２の直線偏光を透過させる吸収型偏光部材と
    　を順に有する光学装置。     A reflective polarizing member that transmits a first linearly polarized light having a first polarization axis and reflects a second linearly polarized light having a second polarization axis that intersects the first polarization axis;
    A TN (Twisted Nematic) type liquid crystal layer containing liquid crystal molecules aligned along the first polarization axis, and a liquid crystal panel having a pair of transparent electrodes facing each other with the TN type liquid crystal layer interposed therebetween;
    An optical polarization device that sequentially absorbs the first linearly polarized light and transmits the second linearly polarized light.
  2. 　前記液晶パネルは、前記第１の直線偏光を前記第２の直線偏光へ変換して透過させる第１のモードと、前記第１の直線偏光を前記第２の直線偏光へ変換せずに透過させる第２のモードとの切り替えを行うものである
    　請求項１記載の光学装置。     The liquid crystal panel converts the first linearly polarized light into the second linearly polarized light and transmits the first linearly polarized light, and transmits the first linearly polarized light without converting it into the second linearly polarized light. The optical apparatus according to claim 1, wherein switching to the second mode is performed.
  3. 　制御部をさらに有し、
    　前記制御部は、前記液晶パネルにおける前記第１のモードと前記第２のモードとの切り替えを、前記１対の透明電極間への直流電圧の印加、または前記１対の透明電極間への１０Ｈｚ（ヘルツ）以下の交流電圧の印加により行う
    　請求項２記載の光学装置。     A control unit;
    The control unit switches between the first mode and the second mode in the liquid crystal panel, applies a DC voltage between the pair of transparent electrodes, or 10 Hz between the pair of transparent electrodes. The optical device according to claim 2, which is performed by applying the following AC voltage.
  4. 　前記制御部は、前記直流電圧の増減速度または前記交流電圧の増減速度を変化させる
    　請求項３記載の光学装置。     The optical device according to claim 3, wherein the control unit changes the increase / decrease speed of the DC voltage or the increase / decrease speed of the AC voltage.
  5. 　前記ＴＮ型液晶層は、０.３６μｍ以上０.５４μｍ未満のΔｎ・ｄを有する
    　請求項１記載の光学装置。     The optical device according to claim 1, wherein the TN liquid crystal layer has Δn · d of 0.36 μm or more and less than 0.54 μm.
  6. 　前記ＴＮ型液晶層の波長５５０ｎｍにおけるΔｎが０．０９以上０．１４未満である
    　請求項５記載の光学装置。     The optical device according to claim 5, wherein Δn at a wavelength of 550 nm of the TN liquid crystal layer is 0.09 or more and less than 0.14.
  7. 　前記液晶分子は、５°以下のプレチルト角を有する
    　請求項１記載の光学装置。     The optical device according to claim 1, wherein the liquid crystal molecules have a pretilt angle of 5 ° or less.
  8. 　画像光として第１の偏光軸を有する第１の直線偏光を出射する表示部と、
    　前記表示部と対向して配置され、前記第１の直線偏光を透過する画像表示モードと外光を反射する外光反射モードとの切り替えを行う表示切替部と
    　を備え、
    　前記表示部は、前記第１の直線偏光を透過すると共に前記第１の偏光軸と交差する第２の偏光軸を有する第２の直線偏光を吸収する第１の吸収型偏光部材を有し、
    　前記表示切替部は、
    　前記第１の直線偏光を透過すると共に前記第２の直線偏光を反射する反射型偏光部材と、
    　前記第１の偏光軸に沿って配向する液晶分子を含むＴＮ（Twisted Nematic）型液晶層、および前記ＴＮ型液晶層を挟んで対向する１対の透明電極を有する液晶パネルと、
    　前記第１の直線偏光を吸収すると共に前記第２の直線偏光を透過させる第２の吸収型偏光部材と
    　を前記表示部の近くから遠ざかる方向に順に有する
    　表示装置。     A display that emits first linearly polarized light having a first polarization axis as image light;
    A display switching unit that is disposed to face the display unit and performs switching between an image display mode that transmits the first linearly polarized light and an external light reflection mode that reflects external light, and
    The display unit includes a first absorptive polarizing member that transmits the first linearly polarized light and absorbs the second linearly polarized light having a second polarization axis that intersects the first polarization axis,
    The display switching unit
    A reflective polarizing member that transmits the first linearly polarized light and reflects the second linearly polarized light;
    A TN (Twisted Nematic) type liquid crystal layer containing liquid crystal molecules aligned along the first polarization axis, and a liquid crystal panel having a pair of transparent electrodes facing each other with the TN type liquid crystal layer interposed therebetween;
    A display device comprising: a second absorptive polarizing member that absorbs the first linearly polarized light and transmits the second linearly polarized light in a direction away from the vicinity of the display unit.
  9. 　前記表示部は、液晶表示素子または有機発光素子を含む
    　請求項８記載の表示装置。     The display device according to claim 8, wherein the display unit includes a liquid crystal display element or an organic light emitting element.
  10. 　表示装置と、
    　前記表示装置を制御する制御部と
    　を備え、
    　前記表示装置は、
    　画像光として第１の偏光軸を有する第１の直線偏光を出射する表示部と、
    　前記表示部と対向して配置され、前記第１の直線偏光を透過する画像表示モードと外光を反射する外光反射モードとの切り替えを行う表示切替部と
    　を備え、
    　前記表示部は、前記第１の直線偏光を透過すると共に前記第１の偏光軸と交差する第２の偏光軸を有する第２の直線偏光を吸収する第１の吸収型偏光部材を有し、
    　前記表示切替部は、
    　前記第１の直線偏光を透過すると共に前記第２の直線偏光を反射する反射型偏光部材と、
    　前記第１の偏光軸に沿って配向する液晶分子を含むＴＮ（Twisted Nematic）型液晶層、および前記ＴＮ型液晶層を挟んで対向する１対の透明電極を有する液晶パネルと、
    　前記第１の直線偏光を吸収すると共に前記第２の直線偏光を透過させる第２の吸収型偏光部材と
    　を前記表示部の近くから遠ざかる方向に順に有する
    　電子機器。     A display device;
    A control unit for controlling the display device,
    The display device
    A display that emits first linearly polarized light having a first polarization axis as image light;
    A display switching unit that is disposed to face the display unit and performs switching between an image display mode that transmits the first linearly polarized light and an external light reflection mode that reflects external light, and
    The display unit includes a first absorptive polarizing member that transmits the first linearly polarized light and absorbs the second linearly polarized light having a second polarization axis that intersects the first polarization axis,
    The display switching unit
    A reflective polarizing member that transmits the first linearly polarized light and reflects the second linearly polarized light;
    A TN (Twisted Nematic) type liquid crystal layer containing liquid crystal molecules aligned along the first polarization axis, and a liquid crystal panel having a pair of transparent electrodes facing each other with the TN type liquid crystal layer interposed therebetween;
    An electronic apparatus comprising: a second absorptive polarizing member that absorbs the first linearly polarized light and transmits the second linearly polarized light in a direction away from the vicinity of the display unit.
PCT/JP2016/069926 2015-08-31 2016-07-05 Optical device, display device and electronic device WO2017038242A1 (en)

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JP2015171080 2015-08-31
JP2015-171080 2015-08-31

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WO2018179772A1 (en) * 2017-03-27 2018-10-04 株式会社村上開明堂 Reflective liquid crystal cell
CN109814302A (en) * 2017-11-22 2019-05-28 斯坦雷电气株式会社 Liquid-crystal apparatus

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WO2018179772A1 (en) * 2017-03-27 2018-10-04 株式会社村上開明堂 Reflective liquid crystal cell
CN109814302A (en) * 2017-11-22 2019-05-28 斯坦雷电气株式会社 Liquid-crystal apparatus

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