EP0477257A1 - Element de commutation et d'affichage a cristaux liquides - Google Patents

Element de commutation et d'affichage a cristaux liquides

Info

Publication number
EP0477257A1
EP0477257A1 EP90909684A EP90909684A EP0477257A1 EP 0477257 A1 EP0477257 A1 EP 0477257A1 EP 90909684 A EP90909684 A EP 90909684A EP 90909684 A EP90909684 A EP 90909684A EP 0477257 A1 EP0477257 A1 EP 0477257A1
Authority
EP
European Patent Office
Prior art keywords
liquid crystal
crystal element
liquid
element according
phase
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP90909684A
Other languages
German (de)
English (en)
Inventor
Claus Escher
Hans-Rolf DÜBAL
Takamasa Harada
Gerhard Illian
Mikio Murakami
Dieter Ohlendorf
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hoechst AG
Original Assignee
Hoechst AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hoechst AG filed Critical Hoechst AG
Publication of EP0477257A1 publication Critical patent/EP0477257A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • G02F1/137—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
    • 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
    • G02F1/137—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
    • G02F1/139—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent
    • G02F1/141—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent using ferroelectric liquid crystals
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/02—Liquid crystal materials characterised by optical, electrical or physical properties of the components, in general
    • C09K19/0225—Ferroelectric
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/34—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring
    • C09K19/3441—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having nitrogen as hetero atom
    • C09K19/345—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having nitrogen as hetero atom the heterocyclic ring being a six-membered aromatic ring containing two nitrogen atoms
    • C09K19/3458—Uncondensed pyrimidines
    • C09K19/3463—Pyrimidine with a carbon chain containing at least one asymmetric carbon atom, i.e. optically active pyrimidines
    • 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
    • G02F1/137—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
    • G02F1/139—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent
    • G02F1/141—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent using ferroelectric liquid crystals
    • G02F1/1416—Details of the smectic layer structure, e.g. bookshelf, chevron, C1 and C2

Definitions

  • ferroelectric liquid crystals serve as switching and display medium (FLC displays) are described, for example, in US Pat. No. 4,367,924. They contain a layer of a ferroelectric liquid-crystalline medium (FLC), which is enclosed on both sides by electrically insulating layers, electrodes and boundary plates, usually glass plates. They also contain a polarizer when in guest-host mode and two polarizers when operating in birefringence mode.
  • the electrically insulating layers are intended to prevent electrical short circuits between the electrodes and the diffusion of ions from the glass of the boundary plates into the FLC.
  • At least one and preferably both of the insulating layers serves as an orientation layer, which brings the FLC into a configuration in which the molecules of the FLC lie with their longitudinal axes parallel to one another, and in which the smectic planes are arranged perpendicularly or obliquely to the orientation layer.
  • orientation layer which brings the FLC into a configuration in which the molecules of the FLC lie with their longitudinal axes parallel to one another, and in which the smectic planes are arranged perpendicularly or obliquely to the orientation layer.
  • FLC displays can therefore be switched bistably. The switching times are in the range of ⁇ s and are shorter, the higher the spontaneous polarization of the FLC used.
  • Liquid crystalline material which forms an S c , Sp, S Q , S or S j phase has proven to be particularly suitable.
  • An FLC material which has an N phase in a temperature range above the ferroelectric phase is also particularly suitable, since in this case the orientation of the LC material is better.
  • the structure of the liquid crystal element according to the invention is illustrated by FIGS. 1 and 2.
  • the liquid crystal element 10 consists of two transparent panes (12, 12 ') and an intermediate space (16) surrounded by sealing material (14).
  • the transparent panes are made of glass, plastic or a similar material.
  • the liquid-crystalline material is filled into the intermediate space (16).
  • Orientation layers (20) are also located on both sides of the intermediate space.
  • B spherical structures of uniform diameter, which are evenly distributed between the two transparent disks 12 and 12 '.
  • the ferroelectric, liquid crystalline material is oriented by orientation layers which are aligned by rubbing.
  • Liquid crystal molecules tend to align parallel to the transparent disks (except when using strongly inclined orientation layers). Because of the formation of a chevron structure and the tendency of the molecules to align in parallel, the angle between two stable molecular states is smaller than the original cone angle of the liquid-crystalline material. This angle is called the effective cone angle 2 ⁇ eff.
  • the most important feature of the liquid crystal element according to the invention is that the effective cone angle can be expanded without an irreversible change in texture occurring. Intermediate values of the cone angle 2 ⁇ eff can also be controlled in a targeted manner by the applied voltage, so that gray levels can be generated.
  • a pulse with a high voltage (V g ) and a length ⁇ s means that the molecules can switch from one state to the other.
  • the subsequent, smaller AC pulses (V ac ) with a length ⁇ ac which are the same length or shorter stabilize the molecules, but do not allow further switching.
  • this LC is aligned by means of an orientation layer rubbed in parallel.
  • the effective one Cone angle 2 ⁇ eff is 10 degrees at 38 ° C, ⁇ e is just + 0.6 at 10 KHz
  • Molecules determines what corresponds here to the projection of the molecules onto the level of the glass of the LC cell.
  • the molecules align themselves parallel to the glass panes.
  • LC layer is the axis of the smectic inclination cone to the glass or Orientation layer inclined, resulting in a Reduction of the effective cone angle leads. If, as indicated in FIGS. 6, 7, a voltage is first applied which is large enough that the molecules on the cone shell can rotate freely and then a voltage such that the molecules can no longer rotate but are still stabilized, this is the case this state is characterized by a balance between electrical torque and that of the orientation layer. As a result, the effective cone angle becomes larger.
  • the liquid crystal element according to the invention which contains a dielectric positive LC mixture as the ferroelectric, smectic material, has the great advantage of having a good contrast due to a large cone angle and, in addition, having no irreversible texture changes at higher voltages, so that even with longer ones Use and frequent switching does not reduce the contrast.
  • a dielectrically negative mixture M is produced from three components:
  • This mixture has the following phase sequence:
  • the dependence of the effective cone angle on the applied voltage V ac is shown in FIG. Fy.
  • the threshold value of the voltage depends on the absolute value of ⁇ e. If the threshold voltage is to be smaller, the amount of ⁇ e must be larger.
  • the effective cone angle changes in a relatively narrow voltage range (here from 7 to 10 volts) from 10 degrees to over 35 degrees. Above 9 volts, an increase in voltage no longer leads to a further widening of the effective cone angle, an irreversible texture change occurs.
  • This phenomenon of negative dielectric LC mixtures is caused by a rotational deformation of the liquid crystal layer.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Liquid Crystal (AREA)
  • Liquid Crystal Substances (AREA)

Abstract

L'élément à cristaux liquides se compose d'un boîtier avec des plaques transparentes et des électrodes, de feuilles de polarisation, de couches d'orientation et d'un matériau smectique ferroélectrique. Ce matériau smectique ferroélectrique est diélectriquement positif (DELTA)>0), ce qui a pour conséquence que l'élément à cristaux liquides présente un contraste important et peut être mis en circuit même en cas d'application de tensions plus élevées (par exemple supérieures à 15 volts). Il n'y a pas de modifications de structure, à la différence de ce qui se passe pour les éléments à cristaux liquides constitués de matériaux diélectriquement négatifs. L'élargissement de l'angle effectif au sommet du cône par application d'un champ électrique décrit ci-dessus peut être employé également pour produire des niveaux de gris.
EP90909684A 1989-06-17 1990-06-09 Element de commutation et d'affichage a cristaux liquides Withdrawn EP0477257A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3919839A DE3919839A1 (de) 1989-06-17 1989-06-17 Fluessigkristall-schalt- und anzeige-element
DE3919839 1989-06-17

Publications (1)

Publication Number Publication Date
EP0477257A1 true EP0477257A1 (fr) 1992-04-01

Family

ID=6382955

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90909684A Withdrawn EP0477257A1 (fr) 1989-06-17 1990-06-09 Element de commutation et d'affichage a cristaux liquides

Country Status (6)

Country Link
US (1) US5353136A (fr)
EP (1) EP0477257A1 (fr)
JP (1) JPH05500866A (fr)
KR (1) KR920702780A (fr)
DE (1) DE3919839A1 (fr)
WO (1) WO1990016007A1 (fr)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2026689C (fr) * 1989-10-27 2000-03-14 Miguel G. Tristani-Kendra Dispositif a cristaux liquides avec echelle des gris
JP2982330B2 (ja) * 1990-04-28 1999-11-22 ソニー株式会社 液晶表示素子
TW476422U (en) * 1992-01-29 2002-02-11 Sharp Kk Liquid crystal display
US5631752A (en) * 1992-12-24 1997-05-20 Casio Computer Co., Ltd. Antiferroelectric liquid crystal display element exhibiting a precursor tilt phenomenon
KR100254648B1 (ko) * 1994-01-26 2000-05-01 보러 롤란드 디에이치에프형 액정 셀을 위한 기동 방법
JPH07287232A (ja) * 1994-04-18 1995-10-31 Fujitsu Ltd 液晶表示装置、その製造方法、および駆動方法
EP0813096A1 (fr) * 1996-06-12 1997-12-17 Rolic AG Dispositif d'affichage, dispositif de commutation, et dispositif de traitement d'images, à cristaux liquides
US6175401B1 (en) * 1997-05-02 2001-01-16 Casio Computer Co., Ltd. Liquid crystal display device having a liquid crystal layer which contains liquid crystal molecules in a plurality of alignment state and method for driving the same
JP3551702B2 (ja) * 1997-05-08 2004-08-11 カシオ計算機株式会社 液晶表示素子とその駆動方法
CN107209431B (zh) 2015-01-20 2020-10-23 香港科技大学 立式螺旋铁电液晶显示单元

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4813767A (en) * 1980-01-08 1989-03-21 Clark Noel A Surface stabilized ferroelectric liquid crystal devices
US4367924A (en) * 1980-01-08 1983-01-11 Clark Noel A Chiral smectic C or H liquid crystal electro-optical device
DE3140078A1 (de) * 1980-10-08 1982-04-22 Kabushiki Kaisha Suwa Seikosha, Tokyo Optische fluessigkristalleinrichtung und drucker, der eine solche optische einrichtung als lichtventil benutzt
FR2557719B1 (fr) * 1984-01-03 1986-04-11 Thomson Csf Dispositif de visualisation a memoire utilisant un materiau ferroelectrique
JPS60156043A (ja) * 1984-01-23 1985-08-16 Canon Inc カイラルスメクティック液晶素子
SE8504760D0 (sv) * 1985-10-14 1985-10-14 Sven Torbjorn Lagerwall Electronic addressing of ferroelectric liquid crystal devices
US5062691A (en) * 1989-10-27 1991-11-05 Minnesota Mining And Manufacturing Company Liquid crystal device with grey scale
US5168381A (en) * 1989-10-30 1992-12-01 University Research Corporation Smectic liquid crystal devices using SSFLC and electroclinic effect based cells

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9016007A1 *

Also Published As

Publication number Publication date
JPH05500866A (ja) 1993-02-18
US5353136A (en) 1994-10-04
KR920702780A (ko) 1992-10-06
DE3919839A1 (de) 1990-12-20
WO1990016007A1 (fr) 1990-12-27

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