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WO2014017796A1 - Plaque de polarisation circulaire dotée d'une transmittance élevée et d'une fonction de réglage de couleur et dispositif d'affichage réfléchissant à cristaux liquides la comportant - Google Patents

Plaque de polarisation circulaire dotée d'une transmittance élevée et d'une fonction de réglage de couleur et dispositif d'affichage réfléchissant à cristaux liquides la comportant Download PDF

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Publication number
WO2014017796A1
WO2014017796A1 PCT/KR2013/006552 KR2013006552W WO2014017796A1 WO 2014017796 A1 WO2014017796 A1 WO 2014017796A1 KR 2013006552 W KR2013006552 W KR 2013006552W WO 2014017796 A1 WO2014017796 A1 WO 2014017796A1
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Prior art keywords
liquid crystal
polarizing plate
wave plate
quarter wave
upper substrate
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Ceased
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PCT/KR2013/006552
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English (en)
Korean (ko)
Inventor
남성현
나균일
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LG Chem Ltd
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LG Chem Ltd
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Priority claimed from KR1020130086069A external-priority patent/KR20140013960A/ko
Application filed by LG Chem Ltd filed Critical LG Chem Ltd
Priority to CN201380002565.7A priority Critical patent/CN103765262A/zh
Priority to US14/232,192 priority patent/US20150219961A1/en
Priority to JP2014545844A priority patent/JP2015505988A/ja
Publication of WO2014017796A1 publication Critical patent/WO2014017796A1/fr
Anticipated expiration legal-status Critical
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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
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G02F1/133634—Birefringent elements, e.g. for optical compensation the refractive index Nz perpendicular to the element surface being different from in-plane refractive indices Nx and Ny, e.g. biaxial or with normal optical axis
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • G02B27/286—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers
    • G02F1/133541—Circular polarisers
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G02F1/133635—Multifunctional compensators
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G02F1/133638—Waveplates, i.e. plates with a retardation value of lambda/n
    • 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
    • G02F2203/00—Function characteristic
    • G02F2203/02—Function characteristic reflective

Definitions

  • the present invention relates to a circular polarizing plate for a reflective liquid crystal display device, and more particularly, to a circular polarizing plate for a reflective liquid crystal display device capable of realizing improved transmittance and color and a reflective liquid crystal display device including the same.
  • Liquid crystal displays may be classified into a transmissive liquid crystal display device using a backlight as a light source and a reflective liquid crystal display device using external natural light or artificial light as a light source without using a backlight.
  • the backlight is used as a light source, a bright image can be realized even in a dark external environment. However, in a bright place, the screen is not recognized well and power consumption is high.
  • the reflection type liquid crystal display uses external natural light or artificial light as a light source, it uses less power and does not have a backlight, which is advantageous in that it is thin and light. Due to these advantages, the adoption of reflective liquid crystal displays in portable terminals such as mobile phones is increasing.
  • Conventional reflective liquid crystal display devices generally include an upper substrate and a lower substrate of a transparent material; A liquid crystal cell interposed between the upper substrate and the lower substrate; A reflection plate formed between the lower or lower substrate of the lower substrate and the liquid crystal cell; A quarter phase difference plate disposed on the upper substrate; And a polarizing plate disposed on the retardation plate.
  • the present invention is to solve the above problems, while having an improved transmittance, circular polarizing plate for a reflection type liquid crystal display device that can implement an excellent color by reducing the yellowish phenomenon and blueish phenomenon (bluish) and It is an object of the present invention to provide a reflective liquid crystal display device including the circular polarizing plate.
  • this invention is a polarizing plate containing the polarizing element whose absorption axis has an angle of 85 degrees-95 degrees with respect to the liquid-crystal orientation direction of the upper substrate side of a liquid crystal cell, and an optical axis is a liquid crystal of the upper substrate side of a liquid crystal cell.
  • a circular polarizing plate for a reflective liquid crystal display device comprising a quarter wave plate having an angle of 130 ° to 140 ° with respect to an alignment direction, wherein the quarter wave plate has a reverse wavelength dispersion.
  • a circular polarizing plate for a liquid crystal display device is provided.
  • the quarter wave plate preferably satisfies the following formula (4) and formula (5).
  • Equation (4) 0.5 ⁇ R in (450) / R in (550) ⁇ 1.0
  • Equation (5) 1.0 ⁇ R in (650) / R in (550) ⁇ 1.3
  • Rin (450) is an in-plane retardation value at 450 nm wavelength
  • Rin (550) is the in-plane retardation value at 550 nm wavelength
  • Rin (650) is the in-plane retardation value at 650 nm wavelength.
  • the polarizing element preferably has a transmittance of 43 to 47%.
  • the polarizing element is preferably a color a value of -1 to -0.6, and a color b value of 0.3 to 2.5 in the CIE coordinate system.
  • the quarter wave plate is preferably a uniaxially stretched film, it may be made of any one of a uniaxially stretched cycloolefin polymer (COP) -based film, a polycarbonate (PC) film, a liquid crystal film or an acrylic film.
  • COP uniaxially stretched cycloolefin polymer
  • PC polycarbonate
  • acrylic film a liquid crystal film or an acrylic film.
  • the quarter wave plate preferably has a surface retardation value of 120nm to 170nm at 550nm wavelength.
  • the quarter wave plate preferably has a thickness direction retardation value of ⁇ 20 nm to 150 nm at a wavelength of 550 nm.
  • the upper substrate the lower substrate which is disposed opposite the upper substrate at regular intervals, the liquid crystal cell interposed between the upper substrate and the lower substrate, between the lower substrate and the liquid crystal cell or the lower And a circular polarizing plate disposed above the upper substrate, and a circular polarizing plate disposed above the upper substrate, wherein the circular polarizing plate has an absorption axis having an angle of 85 ° to 95 ° with respect to the liquid crystal alignment direction of the upper substrate side of the liquid crystal cell.
  • a polarizing plate including a polarizing element and a quarter wave plate disposed between the polarizing plate and the upper substrate, and having an optical axis having an angle of 130 ° to 140 ° with respect to the liquid crystal alignment direction of the upper substrate side of the liquid crystal cell.
  • the quarter wave plate provides a reflection type liquid crystal display device having reverse wavelength dispersion.
  • the reflection type liquid crystal display device is preferably in the IPS mode or ECB mode.
  • the contrast ratio is improved compared to the case of using the conventional circular polarizing plate, so that the visibility is improved, the yellow color is reduced, and the bluish color in the dark state can be reduced. This has the advantage that excellent color can be realized.
  • FIG. 1 is a photograph showing the luminous characteristics according to the phase difference value of the circularly polarizing plates according to Experimental Example 2.
  • FIG. 1 is a photograph showing the luminous characteristics according to the phase difference value of the circularly polarizing plates according to Experimental Example 2.
  • FIG. 4 is a graph showing a contrast ratio according to a change in the Rth (550) value of a quarter wave plate.
  • the inventors of the present invention have repeatedly studied to develop a circularly polarizing plate with improved color in a dark state and a reflective liquid crystal display device including the same, and as a result, the absorption axis of the polarizer and the optical axis of the quarter wave plate are
  • the present invention finds that the above object can be achieved by using a circularly polarizing plate arranged to have a specific angle with the liquid crystal alignment direction of and using a wavelength plate having reverse wavelength dispersion as a quarter wave plate. was completed.
  • the circularly polarizing plate for a reflective liquid crystal display device includes a polarizing plate and an optical axis including a polarizing element having an absorption axis having an angle of 85 ° to 95 ° with respect to the liquid crystal alignment direction of the upper substrate side of the liquid crystal cell. And a quarter wave plate having an angle of 130 ° to 140 ° with respect to the liquid crystal alignment direction of the upper substrate side of the liquid crystal cell, wherein the quarter wave plate has reverse wavelength dispersion.
  • the absorption axis of the polarizing element and the optical axis of the quarter wave plate are 85 ° to 95 ° and 130 ° to 135 ° with respect to the liquid crystal alignment direction of the upper substrate side of the liquid crystal cell, respectively.
  • the visibility and color have been improved.
  • a film having a reverse wavelength dispersion as a quarter-wave plate as in the present invention, a vivid black color can be realized compared to the case of using a film having a constant wavelength dispersion or a flat wavelength dispersion. The rain has been shown to improve dramatically.
  • the circular polarizing plate of the present invention includes (i) a polarizing plate containing a polarizing element and (ii) a quarter wave plate.
  • the polarizing device refers to an optical device for passing only light polarized in a specific direction, generally poly vinyl alcohol (hereinafter referred to as PVA) -based molecular chain is oriented in a certain direction, iodine-based compound Or a dichroic polarizing material.
  • PVA poly vinyl alcohol
  • Such a polarizing element is produced by dyeing an iodine or a dichroic dye on a polyvinyl alcohol-based film, and then stretching and crosslinking in a constant direction.
  • the degree of polymerization of the polyvinyl alcohol is not particularly limited, but considering the freedom of molecular movement and flexible mixing with the containing material, it is preferably about 1,000 to 10,000, more preferably about 1,500 to 5,000. .
  • the polarizing element is arranged such that the absorption axis has an angle of 85 ° to 95 ° with respect to the liquid crystal alignment direction of the upper substrate side of the liquid crystal cell.
  • the liquid crystal alignment direction of the upper substrate side of the liquid crystal cell refers to a direction in which the liquid crystal is aligned through rubbing or light irradiation on a substrate positioned on the viewer side of the liquid crystal cell
  • the absorption axis of the polarizing element is a poly-dyed iodine
  • the polarizing element preferably has a transmittance of 43 to 47%.
  • the polarizing element preferably has a color a value of -1 to -0.6 and a color b value of 0.3 to 2.5 in a CIE coordinate system.
  • Transmittance and color characteristics of the polarizing element may be adjusted by adjusting the iodine concentration or performing a complementary color process during manufacturing of the polarizing element, as described in the preparation examples to be described later. According to the researches of the present inventors, when using the polarization element having the transmittance and the color a and b values as described above, it is possible to implement a more neutral color in the white mode and black mode.
  • the thickness of the said polarizing element is very thin, it is common to attach a protective film to one side or both sides of the said polarizing element, and to form a polarizing plate.
  • a protective film protective films of various materials generally used in the art may be used without limitation.
  • TAC triacetyl cellulose
  • a cycloolefin film, an acrylic film, etc. may be used.
  • the protective films may be attached to the polarizer using an adhesive or the like.
  • the polarizing plate may additionally include a functional film such as a retardation film, a wide viewing angle compensation plate, or a brightness enhancement film in order to further improve the function.
  • the quarter wave plate converts linearly polarized light passing through the polarizing plate into circular polarization.
  • the quarter wave plate of the present invention has an optical axis in the liquid crystal alignment direction of the upper substrate side of the liquid crystal cell. And 130 ° to 140 ° with respect to, preferably about 135 °.
  • the optical axis of the quarter wave plate means an axis having the same value of the electric field intensity of the two orthogonal components of the light passing through the quarter wave plate, generally, when the phase difference film is taken as an example, When stretching in one or two axes to form a phase difference, it refers to the axis in the stretching direction.
  • the present invention is characterized by using a film having reverse wavelength dispersion as the quarter-wave plate.
  • the film having reverse wavelength dispersion means a film having a characteristic of increasing phase retardation as the wavelength of light increases, and more specifically, a film that satisfies the following formula (1).
  • Equation (1) Rin (450) ⁇ Rin (550) ⁇ Rin (650)
  • Rin ( ⁇ ) means an in-plane retardation value at ⁇ nm wavelength. That is, Rin 450 is an in-plane retardation value at 450 nm wavelength, Rin 550 is an in-plane retardation value at 550 nm wavelength, and Rin 650 is an in-plane retardation value at 650 nm wavelength.
  • the in-plane retardation value Rin ( ⁇ ) means a value defined by the following equation (2)
  • the thickness direction retardation value Rth ( ⁇ ) is a value defined by the following equation (3). it means.
  • n x is the refractive index in the in-plane slow axis direction of the quarter wave plate
  • n y is the in-plane fast axis direction of the quarter wave plate
  • the refractive index, n z is the refractive index in the thickness direction of the quarter wave plate
  • d is the thickness of the quarter wave plate.
  • the quarter wave plate of the present invention is not limited thereto, but preferably has a surface retardation value (Rin (550)) of 120 nm to 170 nm at a wavelength of 550 nm. This is because when the Rin 550 satisfies the numerical range, the circularly polarized light conversion of the linearly polarized light in the visible light region can be smoothly performed.
  • Rin (550) surface retardation value
  • the quarter wave plate of the present invention is not limited thereto, but preferably has a thickness direction retardation value (Rth (550)) of -20 to 150 nm at a wavelength of 550 nm. This is because when the Rth 550 satisfies the numerical range, more excellent viewing angle characteristics can be ensured.
  • Rth (550) thickness direction retardation value
  • the quarter wave plate of the present invention may have wavelength dispersion that satisfies the following formulas (4) and (5).
  • Equation (4) 0.5 ⁇ R in (450) / R in (550) ⁇ 1.0
  • Equation (5) 1.0 ⁇ R in (650) / R in (550) ⁇ 1.3
  • R in (450), R in (550), and R in (650) mean in-plane retardation values of the film at wavelengths of 450 nm, 550 nm, and 650 nm, respectively.
  • Equation (3) and Equation (4) when the wavelength dispersion characteristic of the quarter wave plate satisfies Equation (3) and Equation (4), it is possible to implement a neutral white and black color, and has an excellent contrast ratio.
  • light passes through a quarter wave plate and undergoes a polarization change of ⁇ Rin ( ⁇ ) / ⁇ .
  • the quarter wave plate of this invention should just have a reverse wavelength dispersion property
  • the material is not specifically limited.
  • the quarter wave plate of the present invention may be a uniaxially stretched polymer film or a liquid crystal film, and more specifically, a uniaxially stretched cycloolefin polymer (COP) based film, a polycarbonate film, an acrylic film. Or a liquid crystal film or the like.
  • the quarter wave plate of the present invention may be composed of one film, or may be in the form of a film laminate in which two or more films are laminated by a method such as coating, coextrusion or adhesion.
  • the quarter-wave plate having the reverse wavelength dispersion of the present invention is a polycarbonate film having a fluorene skeleton prepared by containing a liquid crystal and filmed and stretched, and a cellulose acetate produced by filming and stretching.
  • a sharper black in the darkroom mode is compared to when using a quarter wave plate having positive wavelength dispersion or flat wavelength dispersion.
  • the advantage is that colors can be implemented.
  • a color shift phenomenon occurs due to a large phase delay at a short wavelength, and as a result, a sharp black color in a dark room mode is obtained.
  • a blue color occurs (bluish).
  • the quarter wave plate having the reverse wavelength dispersion is used, the phase delay becomes smaller toward the shorter wavelength, thereby suppressing the color shift phenomenon as described above, and as a result, a vivid black color can be realized.
  • the reflective liquid crystal display device of the present invention includes an upper substrate, a lower substrate, a liquid crystal cell, a reflecting plate, and a circular polarizing plate, wherein the circular polarizing plate of the present invention is used as the circular polarizing plate.
  • the reflective liquid crystal display device of the present invention the upper substrate, the lower substrate which is disposed opposite the upper substrate at regular intervals, the liquid crystal cell interposed between the upper substrate and the lower substrate, the lower substrate and the liquid crystal And a reflecting plate disposed between cells or below the lower substrate and a circular polarizing plate disposed above the upper substrate, wherein the circular polarizing plate has an absorption axis of 85 ° to 95 with respect to the liquid crystal alignment direction of the upper substrate side of the liquid crystal cell.
  • a polarizing plate including a polarizing element having an angle of ° and disposed between the polarizing plate and the upper substrate, the optical axis has an angle of 130 ° to 140 ° with respect to the liquid crystal alignment direction of the upper substrate side of the liquid crystal cell, It is characterized by including a quarter wave plate having acidity.
  • the upper substrate and the lower substrate may be made of a transparent substrate, for example, glass or a light transmissive plastic substrate.
  • the upper substrate and the lower substrate are disposed to face each other at regular intervals, and switching elements for driving the liquid crystal cell are formed on opposite surfaces of the upper substrate and the lower substrate.
  • the liquid crystal cell may be interposed between the upper substrate and the lower substrate, and may be formed of liquid crystals having positive dielectric anisotropy.
  • the driving mode of the liquid crystal cell varies according to the arrangement and driving state of the liquid crystal in the liquid crystal cell.
  • a reflective liquid crystal display device includes a twist nematic (TN) method, a super twisted nematic (STN) method, and a polymer dispersion.
  • Liquid crystal cells of various modes such as a liquid crystal (PDLC) method, an electric field control birefringence (ECB) method, or a transverse electric field method (IPS) method, may be used.
  • the reflective liquid crystal display device of the present invention is particularly preferably a liquid crystal display device of an electric field control birefringence (ECB) system or a transverse electric field system (IPS) system in view of the viewing angle.
  • EBC electric field control birefringence
  • IPS transverse electric field system
  • the present invention is not limited thereto.
  • the liquid crystal cell gap of the liquid crystal display device is preferably about 2.0 ⁇ 2.4 ⁇ m. This is because the white color improvement effect is most excellent when the liquid crystal cell gap is within the above range.
  • the color difference may occur due to the change in the efficiency of light due to the path difference of the reflected light to the transmitted light.
  • the reflecting plate is to reflect light incident from the outside of the liquid crystal display device to be used as a light source, and is disposed between the lower substrate and the liquid crystal cell or under the lower substrate.
  • the reflective plate may be manufactured by depositing a conductive metal such as aluminum or silver.
  • the reflective liquid crystal display device of the present invention is characterized by using the circular polarizing plate of the present invention described above. That is, the circular polarizing plate includes a polarizing plate including a polarizing element having an absorption axis having an angle of 85 ° to 95 ° and preferably 90 ° with respect to the liquid crystal alignment direction of the upper substrate side of the liquid crystal cell, and disposed between the polarizing plate and the upper substrate.
  • the optical axis may include a quarter wave plate having an angle of 130 ° to 140 ° preferably 135 ° with respect to the liquid crystal alignment direction of the upper substrate side of the liquid crystal cell and having reverse wavelength dispersion. Since the specific contents with respect to the circular polarizing plate are the same as described above, the description is omitted.
  • Polyvinyl alcohol (PVA) film (manufactured by Kuraray Co. Ltd., polymerization degree: 2400) was rinsed in a water bath and a swelling bath, salted in an aqueous solution containing I 2 and KI, and then 5 times in an aqueous solution containing boric acid and KI. Stretched to prepare polarizers. At this time, the concentration of I 2 and the dye bath are as shown in the following [Table 1]. In addition, to adjust the color of the polarizer, the concentration of the KI solution was adjusted to 2-4% level in the complementary color process.
  • TAC triacetyl cellulose
  • FIG. 1 is a graph showing a single transmittance (Ts) of polarizers according to iodine concentration.
  • the quarter wave plate was stacked such that the optical axis had an angle of 75 ° with respect to the absorption axis of the polarizing plate, and the half wave plate was laminated so that the optical axis had an angle of 15 ° with respect to the absorption axis of the polarizing plate.
  • the circular polarizer prepared as described above was attached to the surface of the IPS mode reflective LCD panel.
  • the liquid crystal alignment direction of the upper substrate side of the LCD panel was 45 ° with respect to the liquid crystal panel length direction, and the absorption axis of the circular polarizer plate and the liquid crystal alignment direction were attached to form an angle of 90 °.
  • the circular polarizer prepared as described above was attached to the surface of the IPS mode reflective LCD panel.
  • the liquid crystal alignment direction of the upper substrate side of the LCD panel was 45 degrees with respect to the liquid crystal panel length direction, and the absorption axis of the circular polarizer and the liquid crystal alignment direction were attached to form an angle of 90 degrees.
  • the circular polarizer prepared as described above was attached to the surface of the IPS mode reflective LCD panel.
  • the liquid crystal alignment direction of the upper substrate side of the LCD panel was 45 degrees with respect to the liquid crystal panel length direction, and the absorption axis of the circular polarizer and the liquid crystal alignment direction were attached to form an angle of 90 degrees.
  • the circular polarizer prepared as described above was attached to the surface of the IPS mode reflective LCD panel.
  • the liquid crystal alignment direction of the upper substrate side of the LCD panel was 45 degrees with respect to the liquid crystal panel length direction, and the absorption axis of the circular polarizer and the liquid crystal alignment direction were attached to form an angle of 90 degrees.
  • the circular polarizer prepared as described above was attached to the surface of the IPS mode reflective LCD panel.
  • the liquid crystal alignment direction of the upper substrate side of the LCD panel was 45 degrees with respect to the liquid crystal panel length direction, and the absorption axis of the circular polarizer and the liquid crystal alignment direction were attached to form an angle of 90 degrees.
  • the circular polarizer prepared as described above was attached to the surface of the IPS mode reflective LCD panel.
  • the liquid crystal alignment direction of the upper substrate side of the LCD panel was 45 degrees with respect to the liquid crystal panel length direction, and the absorption axis and the liquid crystal alignment direction of the circular polarizer were attached to form an angle of 45 degrees.
  • a circular polarizing plate was produced by attaching four wave plates. In this case, the quarter wave plate was attached such that the optical axis had an angle of 45 ° with respect to the absorption axis of the polarizing plate.
  • the circular polarizer prepared as described above was attached to the surface of the IPS mode reflective LCD panel.
  • the liquid crystal alignment direction of the upper substrate side of the LCD panel was 45 degrees with respect to the liquid crystal panel length direction, and the absorption axis of the circular polarizer and the liquid crystal alignment direction were attached to form an angle of 90 degrees.
  • the LCD device with a circular polarizing plate of Comparative Example 1 which is a general commercially available reflective circular polarizing plate structure (that is, a structure using a quarter-wave plate and a half-wave plate together), has a white color.
  • the yellowish yellowish
  • Comparative Examples 2, 3, and 6 using the flat wavelength dispersion 1/4 wavelength plate the neutral white color was implemented in the white mode, but the neutral black color was not realized in the black mode, and the greenness was felt.
  • the neutral white color and the black color appeared in both the white mode and the black mode.
  • FIG. 1 shows photographs showing colors of Comparative Examples 1 to 3, 6, and Example 1 in the black mode.
  • Figure 1 (a) is Comparative Example 1, (b) is Comparative Example 2, (c) is Comparative Example 3, (d) is Comparative Example 6, (e) shows the color in the black mode of Example 1 Photos.
  • the LCD device with the circular polarizing plates of Comparative Examples 1 to 3 and 6 exhibits a green color, a red color or a blue color in the black mode, and thus the black color is not good.
  • the blue color is very severe in the black mode.
  • the LCD device with the circularly polarizing plate of Embodiment 1 as shown in FIG. 1E, a neutral black color is realized.
  • the contrast ratio was calculated by measuring the luminance of the black and white colors in the bright and dark rooms of the IPS mode reflective LCD device manufactured by Comparative Examples 1 to 6 and Example 1 with a luminance meter.
  • the measurement result in the bright room is shown in FIG. 2, and the measurement result in the dark room is shown in FIG.
  • the Lw line represents the luminance of white (WHITE)
  • the Lb line represents the luminance of black (BLACK)
  • the luminance value is shown on the left side of the graph.
  • the CR / CRo line represents the contrast ratio (CR / CRo), the value of which is shown on the right side of the graph.
  • Lw o , Lb o , and CR o are measured values when the circularly polarizing plate of Comparative Example 1 is attached.
  • the contrast ratio (CR / CRo) is higher in both the bright and dark rooms than the quarter wave plate having the flat wavelength dispersion. That is, when all the experimental conditions are the same and only the wavelength dispersion characteristics of the 1/4 retardation plate are different, the circularly polarizing plate having the in-plane retardation value of 140 nm is attached to the polarizer having reverse wavelength dispersion as in the present invention. It can be seen that the contrast ratio CR is higher.
  • the viewing angle ( ⁇ ) 75 ° and the azimuth angle ( ⁇ ) 15 ° Contrast ratios were measured at 30 degrees, 45 degrees, 60 degrees, and 75 degrees.
  • the transmittance of the polarizing plate was 43%
  • Rin (550) 140nm of the quarter wave plate
  • the liquid crystal cell was set to the IPS mode LCD
  • the phase difference of the IPS liquid crystal is about 300nm
  • TechWiz LCD was used as a simulation program.
  • the simulation results are shown in FIG. As shown in FIG. 4, it can be seen that the contrast ratio of 10 or more is excellent at all azimuth angles in the range in which the Rth 550 of the quarter wave plate is -20 nm to 150 nm.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Liquid Crystal (AREA)
  • Polarising Elements (AREA)

Abstract

La présente invention concerne une plaque de polarisation circulaire destinée à un dispositif d'affichage réfléchissant à cristaux liquides, comportant : une plaque de polarisation comprenant un élément polarisant dont un axe d'absorption forme un angle de 85° à 95° par rapport à la direction d'alignement des cristaux liquides d'un substrat supérieur pour cellules à cristaux liquides ; et une plaque quart d'onde dont un axe optique forme un angle de 130° à 140° par rapport à la direction d'alignement des cristaux liquides du substrat supérieur pour les cellules à cristaux liquides, la plaque quart d'onde présentant une dispersion inverse des longueurs d'ondes.
PCT/KR2013/006552 2012-07-23 2013-07-23 Plaque de polarisation circulaire dotée d'une transmittance élevée et d'une fonction de réglage de couleur et dispositif d'affichage réfléchissant à cristaux liquides la comportant Ceased WO2014017796A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CN201380002565.7A CN103765262A (zh) 2012-07-23 2013-07-23 高透光性和色彩调节的圆偏光板以及包含该偏光板的反射式液晶显示器
US14/232,192 US20150219961A1 (en) 2012-07-23 2013-07-23 High light transmittance and color adjusting circular polarizing plate and reflective liquid crystal displays comprising the same
JP2014545844A JP2015505988A (ja) 2012-07-23 2013-07-23 高透過度色相調整円偏光板及びこれを含む反射型液晶表示装置

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR10-2012-0080092 2012-07-23
KR20120080092 2012-07-23
KR1020130086069A KR20140013960A (ko) 2012-07-23 2013-07-22 고투과도 색상조정 원편광판 및 이를 포함하는 반사형 액정표시장치
KR10-2013-0086069 2013-07-22

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018505445A (ja) * 2015-01-30 2018-02-22 エルジー・ケム・リミテッド 偏光子

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000081619A (ja) * 1998-06-29 2000-03-21 Sharp Corp 反射型液晶表示装置
JP2002229070A (ja) * 2001-01-30 2002-08-14 Nec Corp 反射型液晶表示装置及びその製造方法
JP2003186014A (ja) * 2001-12-19 2003-07-03 Casio Comput Co Ltd 液晶表示素子
KR20100101981A (ko) * 2009-03-10 2010-09-20 동우 화인켐 주식회사 시야각이 좁은 액정표시장치
KR20110104700A (ko) * 2010-03-17 2011-09-23 주식회사 엘지화학 원편광판 및 이를 포함하는 반사형 액정표시장치

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000081619A (ja) * 1998-06-29 2000-03-21 Sharp Corp 反射型液晶表示装置
JP2002229070A (ja) * 2001-01-30 2002-08-14 Nec Corp 反射型液晶表示装置及びその製造方法
JP2003186014A (ja) * 2001-12-19 2003-07-03 Casio Comput Co Ltd 液晶表示素子
KR20100101981A (ko) * 2009-03-10 2010-09-20 동우 화인켐 주식회사 시야각이 좁은 액정표시장치
KR20110104700A (ko) * 2010-03-17 2011-09-23 주식회사 엘지화학 원편광판 및 이를 포함하는 반사형 액정표시장치

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018505445A (ja) * 2015-01-30 2018-02-22 エルジー・ケム・リミテッド 偏光子
US10302833B2 (en) 2015-01-30 2019-05-28 Lg Chem, Ltd. Polarizer

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