CA2198716A1 - Ferroelectric liquid crystal devices - Google Patents
Ferroelectric liquid crystal devicesInfo
- Publication number
- CA2198716A1 CA2198716A1 CA002198716A CA2198716A CA2198716A1 CA 2198716 A1 CA2198716 A1 CA 2198716A1 CA 002198716 A CA002198716 A CA 002198716A CA 2198716 A CA2198716 A CA 2198716A CA 2198716 A1 CA2198716 A1 CA 2198716A1
- Authority
- CA
- Canada
- Prior art keywords
- liquid crystal
- polymer
- cell walls
- ferroelectric
- monomer
- 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.)
- Abandoned
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
- 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
- C09K19/52—Liquid crystal materials characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
- C09K19/54—Additives having no specific mesophase characterised by their chemical composition
-
- 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
- C09K19/52—Liquid crystal materials characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
- C09K19/54—Additives having no specific mesophase characterised by their chemical composition
- C09K19/542—Macromolecular compounds
-
- 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
-
- 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
- G02F1/1334—Constructional arrangements; Manufacturing methods based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
-
- 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
- G02F1/13775—Polymer-stabilized liquid crystal layers
Abstract
In order to reduce the effects of impact on liquid crystal devices a polymer network is introduced into ferroelectric liquid crystal cells. A liquid crystal device comprises two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, a layer of a smectic liquid crystal material enclosed between the cell walls, characterised in that the liquid crystal material contains a small amount of monomer. The liquid crystal material may also contain a photoinitiator. The monomer material may be cured to produce the polymer network; the curing may be carried out in the presence of an electric or magnetic field. Further, the monomer may be cured in an isotropic or liquid crystal phase.
Description
~o 96107l23 2 31 9 8 7 i ~ ~ PcT/Gss5/02036 FERROELECTRIC LIQUID CRYSTAL DEVICES
Th~s invention relates to novel ferroelectric liquid crystal devices.
Liquid crystal m~tPri~l~ are widely used in liquid crystal displays such as watches, c~1r~ tor.s etc. Most displays of this type consist of a thin film of a liquid crystalline composition sandLwiched in a cell bGlw~G1l two s~ 1Pe, at least one of which is J~ , and having ~ "1L electrodes on their inner ~ ri~ces On applying a potential dirrG1G.lce across the electrodes the ~ nm~nt of the molecules of the liquid crystalline c~ o~ition is altered, res111*ng in an electro-optic effect in the m~tPri~l, which is exploited by the display. Most often electro-optic effects in the nPm~tic liquid crystal phase are exploited in such displays. Examples of types of displays include the twisted nt-,m~tir., the Free~1Ptir~ 7 effect device, cholesteric memory mode device, cholesteric to nP.m~tic phase change effect device, dynamic sc~ effect device, two frequency :;witch;l~g effect device and the '~u~ lwist' effect device. Other types of device include active matrix twisted nrm~tir.S, pi-cells and ferroelectric liquid crystal devices.
Ferroelectric smectic liquid crystal m~t~ , which can be produced by mixing an achiral host and a chiral dopant, use the ferroelectric properties of the tilted chiral smectic C, F, G, H, I, J and K phases. The chiral smectic C phase is deno~ed Sc* with the asterisk denoting chirality. The Sc* phase is PenPr~11y considered to be the most useful as it is the fastest ~wilc,~ g. Ferroelectric smectic liquid crystal m~tPri~l~ should ideally possess the following chz..~ l;r.~ low viscosity, controllable ~ul,l~leous polarisation (Ps) and an Sc* phase that persists over a broad le~ c1~ range, which should include ambient ~ , and ~xhihit~ chemical and photorhpmir~l stability. ~ trri~l~ which possess these çh~offer the prospect of very fast ~wilclfil1g liquid crystal cn..~ ;..g devices. Some applications of ferroelectric liquid crystals are described by J. S. Patel and J. W. Goodby in Opt. Eng., 1987, 26, 273.
W 096tO7123 219 ~ 7 1 6 2 PCTtGB95tO2036 In ferroelectric liquid crystal devices the molecules switch between di~~ lignm~nt directions depending on the polarity of an applied electric field. These devices can be arranged to exhibit bistability where the molecules tend to remain in one of two states until ~wilcl1ed to the other switched state. Such devices are termed surface stabilised ferroelectric devices, e.g. as described in US 5061047 and US 4367924 and US 4563059. This bistability allows the mllltipleY addressing of quite large and complex devices.
One common multiplex display has display clellle~ , i.e. pixels, ~ ged in an x, y matrix format for the display of e.g. alpha mlm~lic r~ t~,~ The matrix format is provided by forming the electrodes on one slide as a series of column electrodes, and the electrodes on the other slide as series of row electrodes. The int~r~ectio~ between each column and row forrn addressable el~m~nt~ or pixels. Other matrix layouts are known, e.g. seven bar nlml~ri~
displays.
There are many di~lclll multirleY addressing s~hl-m~s. A common feature involves the appli~ti~ ~ of a voltage, called a strobe voltage to each row or line in sequence.
Coinrj~lPnt~lly with the strobe applied at each row, a~ ;dle voltages, called data voltages, are applied to all column electrodes. The di~l~nces between the dirr~ s~h~m~s lies in the shape of the strobe and data voltage waveforms.
Other addressing sr~ s are described in GB-2,146,473-A; GB-2,173,336-A;
GB-2,173,337-A; GB-2,173,629-A; WO 89/05025; Harada et al 1985 S.I.D. Paper 8.4 pp 131-134; Lagerwall et al 1985 I.D.R.C. pp 213-221 and P Maltese et al in Proc 1988 I.D.~.C. p 90-101 Fast Addressing for Ferroelectric LC Display Panels.
96/07123 ~?~ 98 7~ ~ PCT/GB95/02036 The mzlt~riZ~l may be switched between its two states by two strobe pulses of opposite sign, in conjunction with a data w~vefo~ ;vcly, a blanking pulse may be used to switch the mzlt~o:rizll into one of its states. Perio~lie~lly the sign of the bl~nkin~ and the strobe pulses may be ~lt~rn~t~-l to ~ a net d.c. value.
These blanking pulses are normally greater in ~mrlitll~le and length of applie~tit-n than the strobe pulses so that the m~t('r~ wiL~i~es irrespective of which of the two data w~vcr~ is applied to any one ;--~ ~e~il;on. Blanking pulses may be applied on a line by line basis ahead of the strobe, or the whole display may be blanked at one time, or a group of lines may be .~imlllt~neously blanked.
It is well known in the field of ferroelectric liquid crystal device technology that, in order to achieve the highest ~- r"~ ...re from devices, it is hll~ulL~lL to use ll~ixLulcs of colll~uu,,ds which give mZIteriZIl~ pos~ ing the most suitable ferroelectric smectic cll~r~r,tçri~tic~ for particular types of device.
Devices can be ~ çd for speed by ctn~i~er~ti-n of the rcil,ol.~e time vs pulse voltage curve. This rrl~tinn~hir may show a ...;..;....~.. in the ~wik,l~ g time (t~nj~) at a p~uL.;ul~
applied voltage (Vmin). At voltages higher or lower than Vmjn the swik;l~illg time is longer than t~njn. It is well lmrl~r~tood that devices having such a .. ;.. ;........ in their ,c~onse time vs voltage curve can be mllltiple~r driven at high duty ratio with higher c~ than other ferroelectric liquid crystal devices. It is ~rt~ d that the said .. ;.. ;... ...in the l~onse time vs voltage curve should occur at low applied voltage and at short pulse length ~ e-;L~ly to allow the device to be driven using a low voltage source and fast frame address refresh rate.
WO 96/07123 . ~ ~. PCT/GB9~102036 -219871 ~ 4 Typical known m~t~riAl~ (where m~teri~ls are a mixLure of compound having suitable liquid crystal çh~r~tPri~tics) which do not allow such a ",;";..,-.", when inrl~ e~l in a ferroelectric device include the c~""",l lcially available m~t~riAl~ known as SCE13 and ZLI-3654 (both supplied by Merck UK Ltd, Poole, Dorset). A device which does show such a ...i~
may be co,~l,u.iLed according to PCT GB 88/01004 and lltili~ing m~tPri~le such as e.g. co,l",l~ ;ially available SCE8 (Merck UK Ltd). Other ~ ,lcs of prior art mz~tt~ri~l~
are e?~lnrlifietl by PCT/GB/86/00040, PCT/GB87/00441 and UK 2232416B.
There are problems relating to the ",rçl~A~ Al stability of ferroelectric liquid crystal devices.
For çxAmple if a force is applied to a device, e.g. it is dropped or it is subjected to some sort of impact then the cell may be ~ Age-l usuAlly bec~use the Ali nmlont is adversely ~ffectP~1 ~O~ 96/07123 21 9 8 71 6 PCT/GB95/02036 The present invention ovG,~;ullles the above problems relating to the mecll~nic~l stability of ferroelectric liquid crystal cells by the incGl~o,dlion of a m~ n~:)mer m~tPri~l with a ferroelectric liquid crystal m~tPri~l According to this invention a liquid crystal device cn~ .. ;C~c two spaced cell walls each bearing electrode ~ s and treated on at least one facing surface with an ~lignm,o.nt layer, a layer of a smectic liquid crystal m~tPrl~l Pn~.klsed bG~W~Gll the cell walls, ,u~* . ;~e(l in that the liquid crystal m~tPri~l contains a small arnount of monnmPr.
Accoldill~, to a further aspect of this invention the liquid crystal m~tPri~l may also contain a phu~
According to a further aspect of this invention the m- nnmPr may be cured with or without the ~sc;llce of a field.
The m~t~n~l may be cured in an isotropic or pl~f~al~ly a liquid crystal phase, for ~ ,le a Sc phase.
Preferably the monomer is present up to an amount of 10w~%, more pl~r~bly up to 5% and even more pl~;r~ bly the amount of monomer present lies in the range 0.01-2.0%.
Typically the curing involves W curing or heat curing.
On curing the monomeric m~tPri~l may be partly or fully poly..,~ e~l WO 96/07123 1 9 8 71 ~ PCT/GB95/02036 !~
A furLher aspect of this invention provides for a method of redurinE the ~usc~libility of ferroelectric liquid crystal cells to impact damage compri~in~ the steps of providing a liquid crystal device compri~inE two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an ~ nmPnt layer, a layer of a smectic liquid crystal m~teri~l Pnr.lc sed bc;Lween the cell walls, rh~r~ctrri~ed by the inclusion of a small amount of monomer m~tP.ri~l.
For this method the ferroelectric liquid crystal cell may be surface stabilised.
A further aspect of this invention provides for an electro-optic device co.~ç,. ;~ two spaced cell walls each bearing an electrode structure and treated on at least one facing surface with an ali~nmpnt layer, a layer of a polymer liqu d crystal m~tçri~l and ferroelectric liquid crystal m~teri~l enclosed b~tw~en the cell walls rh~r~rt~ri~erl in that the polymer liquid crystal is prepared by the in-situ polymçri~tion of a mn~ mPr.
The monomp~r may be a liquid crystal monomer.
~96/07123 198 71 ~ rcT/GBg5l02036 The invention will now be described by way of e~mrle only with lcÇc.~.lce to the following ~ LWIIlgS ofwhich:-Figure 1 ill~ les a liquid crystal device.
Figures 2a and 2b show the before (2a) and after (2b) effects of dropping a ball-bearing from a height of 2cm onto a liquid crystal cell co~ ;llil.g SCE8 only.
Figures 3a and 3b show the before (3a) and after (3b) effects of dlU~J~)illg a ball-bearing from a height of 2cm onto a liquid crystal cell co..l;~ g SCE8 and 1% of RLCl before curing.
Figures 4a and 4b show the before (4a) and after (4b) effects of dropping a ball-bealirlg from a height of 4cm onto a liquid crystal cell co~ ;";~g SCE8 and 1% of RLCl after curing.
Figures 5a and 5b show the before (5a) and after (5b) effects of L~ g a ball-bearing from a height of 2cm onto a liquid crystal cell COIll;7;ll;l~g SCE8 and 0.5% of RLCl before curing.
Figures 6a and 6b show the before (6a) and after (6b) effects of dropping a ball-bearing from a height of 2cm onto a liquid crystal cell c~,.l~;.,i,-g SCE8 and 0.5% of RLCl after curing.
Figure 7 shows the after effect of dropping a ball-bearing from a height of 3cm onto a liquid crystal cell co~ -g SCE8 and 0.5% of RLCl after curing.
Figure 8 ill~ s a Vmjn, tmjn graph for a th~rm~lly aligned sample of SCE8 + 0.5% RLCl + a~r~ tely 0.1% Darocur 1173 co~ ~cd to a sample of SCE8.
Th~s invention relates to novel ferroelectric liquid crystal devices.
Liquid crystal m~tPri~l~ are widely used in liquid crystal displays such as watches, c~1r~ tor.s etc. Most displays of this type consist of a thin film of a liquid crystalline composition sandLwiched in a cell bGlw~G1l two s~ 1Pe, at least one of which is J~ , and having ~ "1L electrodes on their inner ~ ri~ces On applying a potential dirrG1G.lce across the electrodes the ~ nm~nt of the molecules of the liquid crystalline c~ o~ition is altered, res111*ng in an electro-optic effect in the m~tPri~l, which is exploited by the display. Most often electro-optic effects in the nPm~tic liquid crystal phase are exploited in such displays. Examples of types of displays include the twisted nt-,m~tir., the Free~1Ptir~ 7 effect device, cholesteric memory mode device, cholesteric to nP.m~tic phase change effect device, dynamic sc~ effect device, two frequency :;witch;l~g effect device and the '~u~ lwist' effect device. Other types of device include active matrix twisted nrm~tir.S, pi-cells and ferroelectric liquid crystal devices.
Ferroelectric smectic liquid crystal m~t~ , which can be produced by mixing an achiral host and a chiral dopant, use the ferroelectric properties of the tilted chiral smectic C, F, G, H, I, J and K phases. The chiral smectic C phase is deno~ed Sc* with the asterisk denoting chirality. The Sc* phase is PenPr~11y considered to be the most useful as it is the fastest ~wilc,~ g. Ferroelectric smectic liquid crystal m~tPri~l~ should ideally possess the following chz..~ l;r.~ low viscosity, controllable ~ul,l~leous polarisation (Ps) and an Sc* phase that persists over a broad le~ c1~ range, which should include ambient ~ , and ~xhihit~ chemical and photorhpmir~l stability. ~ trri~l~ which possess these çh~offer the prospect of very fast ~wilclfil1g liquid crystal cn..~ ;..g devices. Some applications of ferroelectric liquid crystals are described by J. S. Patel and J. W. Goodby in Opt. Eng., 1987, 26, 273.
W 096tO7123 219 ~ 7 1 6 2 PCTtGB95tO2036 In ferroelectric liquid crystal devices the molecules switch between di~~ lignm~nt directions depending on the polarity of an applied electric field. These devices can be arranged to exhibit bistability where the molecules tend to remain in one of two states until ~wilcl1ed to the other switched state. Such devices are termed surface stabilised ferroelectric devices, e.g. as described in US 5061047 and US 4367924 and US 4563059. This bistability allows the mllltipleY addressing of quite large and complex devices.
One common multiplex display has display clellle~ , i.e. pixels, ~ ged in an x, y matrix format for the display of e.g. alpha mlm~lic r~ t~,~ The matrix format is provided by forming the electrodes on one slide as a series of column electrodes, and the electrodes on the other slide as series of row electrodes. The int~r~ectio~ between each column and row forrn addressable el~m~nt~ or pixels. Other matrix layouts are known, e.g. seven bar nlml~ri~
displays.
There are many di~lclll multirleY addressing s~hl-m~s. A common feature involves the appli~ti~ ~ of a voltage, called a strobe voltage to each row or line in sequence.
Coinrj~lPnt~lly with the strobe applied at each row, a~ ;dle voltages, called data voltages, are applied to all column electrodes. The di~l~nces between the dirr~ s~h~m~s lies in the shape of the strobe and data voltage waveforms.
Other addressing sr~ s are described in GB-2,146,473-A; GB-2,173,336-A;
GB-2,173,337-A; GB-2,173,629-A; WO 89/05025; Harada et al 1985 S.I.D. Paper 8.4 pp 131-134; Lagerwall et al 1985 I.D.R.C. pp 213-221 and P Maltese et al in Proc 1988 I.D.~.C. p 90-101 Fast Addressing for Ferroelectric LC Display Panels.
96/07123 ~?~ 98 7~ ~ PCT/GB95/02036 The mzlt~riZ~l may be switched between its two states by two strobe pulses of opposite sign, in conjunction with a data w~vefo~ ;vcly, a blanking pulse may be used to switch the mzlt~o:rizll into one of its states. Perio~lie~lly the sign of the bl~nkin~ and the strobe pulses may be ~lt~rn~t~-l to ~ a net d.c. value.
These blanking pulses are normally greater in ~mrlitll~le and length of applie~tit-n than the strobe pulses so that the m~t('r~ wiL~i~es irrespective of which of the two data w~vcr~ is applied to any one ;--~ ~e~il;on. Blanking pulses may be applied on a line by line basis ahead of the strobe, or the whole display may be blanked at one time, or a group of lines may be .~imlllt~neously blanked.
It is well known in the field of ferroelectric liquid crystal device technology that, in order to achieve the highest ~- r"~ ...re from devices, it is hll~ulL~lL to use ll~ixLulcs of colll~uu,,ds which give mZIteriZIl~ pos~ ing the most suitable ferroelectric smectic cll~r~r,tçri~tic~ for particular types of device.
Devices can be ~ çd for speed by ctn~i~er~ti-n of the rcil,ol.~e time vs pulse voltage curve. This rrl~tinn~hir may show a ...;..;....~.. in the ~wik,l~ g time (t~nj~) at a p~uL.;ul~
applied voltage (Vmin). At voltages higher or lower than Vmjn the swik;l~illg time is longer than t~njn. It is well lmrl~r~tood that devices having such a .. ;.. ;........ in their ,c~onse time vs voltage curve can be mllltiple~r driven at high duty ratio with higher c~ than other ferroelectric liquid crystal devices. It is ~rt~ d that the said .. ;.. ;... ...in the l~onse time vs voltage curve should occur at low applied voltage and at short pulse length ~ e-;L~ly to allow the device to be driven using a low voltage source and fast frame address refresh rate.
WO 96/07123 . ~ ~. PCT/GB9~102036 -219871 ~ 4 Typical known m~t~riAl~ (where m~teri~ls are a mixLure of compound having suitable liquid crystal çh~r~tPri~tics) which do not allow such a ",;";..,-.", when inrl~ e~l in a ferroelectric device include the c~""",l lcially available m~t~riAl~ known as SCE13 and ZLI-3654 (both supplied by Merck UK Ltd, Poole, Dorset). A device which does show such a ...i~
may be co,~l,u.iLed according to PCT GB 88/01004 and lltili~ing m~tPri~le such as e.g. co,l",l~ ;ially available SCE8 (Merck UK Ltd). Other ~ ,lcs of prior art mz~tt~ri~l~
are e?~lnrlifietl by PCT/GB/86/00040, PCT/GB87/00441 and UK 2232416B.
There are problems relating to the ",rçl~A~ Al stability of ferroelectric liquid crystal devices.
For çxAmple if a force is applied to a device, e.g. it is dropped or it is subjected to some sort of impact then the cell may be ~ Age-l usuAlly bec~use the Ali nmlont is adversely ~ffectP~1 ~O~ 96/07123 21 9 8 71 6 PCT/GB95/02036 The present invention ovG,~;ullles the above problems relating to the mecll~nic~l stability of ferroelectric liquid crystal cells by the incGl~o,dlion of a m~ n~:)mer m~tPri~l with a ferroelectric liquid crystal m~tPri~l According to this invention a liquid crystal device cn~ .. ;C~c two spaced cell walls each bearing electrode ~ s and treated on at least one facing surface with an ~lignm,o.nt layer, a layer of a smectic liquid crystal m~tPrl~l Pn~.klsed bG~W~Gll the cell walls, ,u~* . ;~e(l in that the liquid crystal m~tPri~l contains a small arnount of monnmPr.
Accoldill~, to a further aspect of this invention the liquid crystal m~tPri~l may also contain a phu~
According to a further aspect of this invention the m- nnmPr may be cured with or without the ~sc;llce of a field.
The m~t~n~l may be cured in an isotropic or pl~f~al~ly a liquid crystal phase, for ~ ,le a Sc phase.
Preferably the monomer is present up to an amount of 10w~%, more pl~r~bly up to 5% and even more pl~;r~ bly the amount of monomer present lies in the range 0.01-2.0%.
Typically the curing involves W curing or heat curing.
On curing the monomeric m~tPri~l may be partly or fully poly..,~ e~l WO 96/07123 1 9 8 71 ~ PCT/GB95/02036 !~
A furLher aspect of this invention provides for a method of redurinE the ~usc~libility of ferroelectric liquid crystal cells to impact damage compri~in~ the steps of providing a liquid crystal device compri~inE two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an ~ nmPnt layer, a layer of a smectic liquid crystal m~teri~l Pnr.lc sed bc;Lween the cell walls, rh~r~ctrri~ed by the inclusion of a small amount of monomer m~tP.ri~l.
For this method the ferroelectric liquid crystal cell may be surface stabilised.
A further aspect of this invention provides for an electro-optic device co.~ç,. ;~ two spaced cell walls each bearing an electrode structure and treated on at least one facing surface with an ali~nmpnt layer, a layer of a polymer liqu d crystal m~tçri~l and ferroelectric liquid crystal m~teri~l enclosed b~tw~en the cell walls rh~r~rt~ri~erl in that the polymer liquid crystal is prepared by the in-situ polymçri~tion of a mn~ mPr.
The monomp~r may be a liquid crystal monomer.
~96/07123 198 71 ~ rcT/GBg5l02036 The invention will now be described by way of e~mrle only with lcÇc.~.lce to the following ~ LWIIlgS ofwhich:-Figure 1 ill~ les a liquid crystal device.
Figures 2a and 2b show the before (2a) and after (2b) effects of dropping a ball-bearing from a height of 2cm onto a liquid crystal cell co~ ;llil.g SCE8 only.
Figures 3a and 3b show the before (3a) and after (3b) effects of dlU~J~)illg a ball-bearing from a height of 2cm onto a liquid crystal cell co..l;~ g SCE8 and 1% of RLCl before curing.
Figures 4a and 4b show the before (4a) and after (4b) effects of dropping a ball-bealirlg from a height of 4cm onto a liquid crystal cell co~ ;";~g SCE8 and 1% of RLCl after curing.
Figures 5a and 5b show the before (5a) and after (5b) effects of L~ g a ball-bearing from a height of 2cm onto a liquid crystal cell COIll;7;ll;l~g SCE8 and 0.5% of RLCl before curing.
Figures 6a and 6b show the before (6a) and after (6b) effects of dropping a ball-bearing from a height of 2cm onto a liquid crystal cell c~,.l~;.,i,-g SCE8 and 0.5% of RLCl after curing.
Figure 7 shows the after effect of dropping a ball-bearing from a height of 3cm onto a liquid crystal cell co~ -g SCE8 and 0.5% of RLCl after curing.
Figure 8 ill~ s a Vmjn, tmjn graph for a th~rm~lly aligned sample of SCE8 + 0.5% RLCl + a~r~ tely 0.1% Darocur 1173 co~ ~cd to a sample of SCE8.
2~9~71 ~
WO 96107123 . . . ;'~ PCT/GB9S102036 The liquid crystal device con~i~t~ of two Ll~ dlc-lL plates, 1 and 2, for example made from glass. These plates are coated on their internal face with lldl~dlclll conducting electrodes 3 and 4. An ~lignm~nt layer is introduced onto the internal faces of the cell so that a planar ol;en~ n of the molecules making up the liquid crystalline m~tPri~l will be al~pn~ n;l~t;ly parallel to the glass plates 1 and 2. This is done by coating the glass plates 1, 2 co rl~te with con~lllctin~ electrodes 3, 4 with layers of film 5 and 6 of a suitable polymer, e.g.
polyimide. The electrodes 3, 4 may be formed into row and column electrodes so that the s~;!;o~ between each column and row form an x, y matrix of addressable elPmtonte or pixels. Prior to the cOllaLlu~iLion of the cell the films 5, 6 are rubbed with a soft tissue in a given direction, the l.ll~hlg directions being arranged parallel (same or opposite direction) UpOll collsL~ Lion of the cell. A spacer 7 e.g. of polymethyl mçth~crylate s~ es the glass plates 1 and 2 to a suitable ~ t~n~e e.g. 2 microns. Liquid crystal m~tPri~l (typically inr.lllrlinp at least one type of monomPr and an ilfiLi~Lol) 8 is introduced bGLwGell glass plates 1, 2 by filling the space in bcLwGtll them. This may be done by flow filling the cell using standard techniques.
The spacer 7 is sealed with an adhesive 9 in a vacuum using an e~ ting technique.
Pola~isers 10, 11 may be arranged in front of and behind the cell. In order to assist the s~ m~-nt of the liquid crystal m~tPri~l, vatious techniques may be used. One of these techniques involves thPrm~lly cycling the cell. The m~tPris~l may then be cured with or without the ~ ,nce of an electric or m~gnPtic field and also with or without the plGsGllce of a ph~LoilliLidL~Jl. AlLGlll2lLively the liquid crystal m~tPri~l may be ".~ ;"~(1 at the filling L~AlllJ~d~UI~ and ~UI~S~-Iu~ r cured at that ~
~96/07123 716 PCTIGlil95102036 The curing of the m~teri~l may result in a polymer ll~lv~o-k comrriein~ polymers of varying molecular weight. There may also be present in small amounts unreacted monr.m,-r.
The device may operate in a tr~nemieeive or reflective mode. In the former, light passing ~rough the device, e.g. from a t~lngeten bulb, is selectively ~ "~,..illed or blocked to form the desired display. In the reflective mode a mirror (12) is placed behind the second polariser 11 to reflect ambient light back through the cell and two polarisers. By making the mirror partly reflecting, the device may be operated both in a ~ x~ ;ve and reflective mode.
In an ~ ;ve embodiment a single polariser and dye m~t.-ri~l may be combined.
A number of tests were carried out to assess the rÇciet~nce of the device to m~ch~nic~l shock.
In order to test for ~er.l~ shock a hollowed tube was sllep~n~1~cl vertically over a liquid crystal cell. At regular intervals holes were cut into the tube so that a rod could be il~.t~d h~ ulll~lly into the tube. A steel ball-bearing, weighing 1.04g, was then ilLs~led into the top end of the tube so that it came to rest on the hc.li~u~ l rod. The rod could then be removed and the ball-bearing allowed to drop onto the liquid crystal cell. The energy of irnpact of the ball-bearing on the liquid crystal cell could then be ~
Having carried out tests of the above type it was then possible to assess the nature of the damage inflicterl by visual inspection and by ~e!i~e~;lIg some of the :~wilcl~ g c l~ . t~ ;ce of the liquid crystal cell.
2~9~716 .
WO 96107123 . . . ;'~ PCT/GB9S102036 The liquid crystal device con~i~t~ of two Ll~ dlc-lL plates, 1 and 2, for example made from glass. These plates are coated on their internal face with lldl~dlclll conducting electrodes 3 and 4. An ~lignm~nt layer is introduced onto the internal faces of the cell so that a planar ol;en~ n of the molecules making up the liquid crystalline m~tPri~l will be al~pn~ n;l~t;ly parallel to the glass plates 1 and 2. This is done by coating the glass plates 1, 2 co rl~te with con~lllctin~ electrodes 3, 4 with layers of film 5 and 6 of a suitable polymer, e.g.
polyimide. The electrodes 3, 4 may be formed into row and column electrodes so that the s~;!;o~ between each column and row form an x, y matrix of addressable elPmtonte or pixels. Prior to the cOllaLlu~iLion of the cell the films 5, 6 are rubbed with a soft tissue in a given direction, the l.ll~hlg directions being arranged parallel (same or opposite direction) UpOll collsL~ Lion of the cell. A spacer 7 e.g. of polymethyl mçth~crylate s~ es the glass plates 1 and 2 to a suitable ~ t~n~e e.g. 2 microns. Liquid crystal m~tPri~l (typically inr.lllrlinp at least one type of monomPr and an ilfiLi~Lol) 8 is introduced bGLwGell glass plates 1, 2 by filling the space in bcLwGtll them. This may be done by flow filling the cell using standard techniques.
The spacer 7 is sealed with an adhesive 9 in a vacuum using an e~ ting technique.
Pola~isers 10, 11 may be arranged in front of and behind the cell. In order to assist the s~ m~-nt of the liquid crystal m~tPri~l, vatious techniques may be used. One of these techniques involves thPrm~lly cycling the cell. The m~tPris~l may then be cured with or without the ~ ,nce of an electric or m~gnPtic field and also with or without the plGsGllce of a ph~LoilliLidL~Jl. AlLGlll2lLively the liquid crystal m~tPri~l may be ".~ ;"~(1 at the filling L~AlllJ~d~UI~ and ~UI~S~-Iu~ r cured at that ~
~96/07123 716 PCTIGlil95102036 The curing of the m~teri~l may result in a polymer ll~lv~o-k comrriein~ polymers of varying molecular weight. There may also be present in small amounts unreacted monr.m,-r.
The device may operate in a tr~nemieeive or reflective mode. In the former, light passing ~rough the device, e.g. from a t~lngeten bulb, is selectively ~ "~,..illed or blocked to form the desired display. In the reflective mode a mirror (12) is placed behind the second polariser 11 to reflect ambient light back through the cell and two polarisers. By making the mirror partly reflecting, the device may be operated both in a ~ x~ ;ve and reflective mode.
In an ~ ;ve embodiment a single polariser and dye m~t.-ri~l may be combined.
A number of tests were carried out to assess the rÇciet~nce of the device to m~ch~nic~l shock.
In order to test for ~er.l~ shock a hollowed tube was sllep~n~1~cl vertically over a liquid crystal cell. At regular intervals holes were cut into the tube so that a rod could be il~.t~d h~ ulll~lly into the tube. A steel ball-bearing, weighing 1.04g, was then ilLs~led into the top end of the tube so that it came to rest on the hc.li~u~ l rod. The rod could then be removed and the ball-bearing allowed to drop onto the liquid crystal cell. The energy of irnpact of the ball-bearing on the liquid crystal cell could then be ~
Having carried out tests of the above type it was then possible to assess the nature of the damage inflicterl by visual inspection and by ~e!i~e~;lIg some of the :~wilcl~ g c l~ . t~ ;ce of the liquid crystal cell.
2~9~716 .
One of ~e m~nomt?rS tested was the commercially available (MERCK, UK) RLCl. Thishas the following formula:
C~2=C~co2 (CH2) 6 ~C2 ~
21 9 ~ 7 ~ 6 Any ferroelectric ~ Lulc is suitable to be used in a device described by the current invention. Some examples are commercially available (Merck, UK) SCE8 and SCE13.
Any monomer is suitable to be used in a device described by the invention.
FY~mrles of suitable photoiniti~t~rs include Darocurs and Igacurs available from Merck UK such as Darocur 1173 or 4265 and Igacur 651. There are various UV curables which are available, some examples are Electrolite c~,~uldLion m~ft~ri~l~ such as ELC 4481 available through LlL~ .ol ics Ltd, Ki~llin~ton, Oxon.
Fx~rnl le 1 SCE13 +5%RLCl +~ O~ t~ly0.1%Darocur 1173.
Fx~m~I le ?
SCE8 + 1% RLCl + d~l~lv~ ely 0.1% Darocur 1173.
F.~m~rle 3 SCE8 + 0.5% RLCl + ~plul~illlately 0.1% Darocur 1173. Therm~lly ~ n~-l tmin against Vmjn plots were run for e~mrle 3.
For ~ mrle 3, one cell was cured a/ in the ~l~;st;llce of a d.c. field and another cell b/ was cured without the field. It was only for the cell cured without the presence of a field (3b) that electro-optic ~wilcl~il~g studies for example tmjn, Vmjn studies could be carried out on.
WO96/07123 219 8 7 ~ t; 12 PCT/GB95/02036 Figures 2-7 illustrate the appearance of liquid crystal cells viewed under a microsco~e before and after they had been subjected to merh~nir~l shock. Typically cells were 1.5-Z.O~lm thick for these ~ hllcnts, though cells of any suitable thic~n~ee could have been used.
For the examples contained in Figures 2-7, all of those that were cured were flow filled, therrn~lly cycled and cured in the Sc phase under a W lamp with no field applied. The initiator used was Darocur 1173 (~IJro?~illlately 0.1%).
Fx~mples were also tested wherein the m~teri~le were cured in the isotropic state after flow filling in the isotropic state.
C~2=C~co2 (CH2) 6 ~C2 ~
21 9 ~ 7 ~ 6 Any ferroelectric ~ Lulc is suitable to be used in a device described by the current invention. Some examples are commercially available (Merck, UK) SCE8 and SCE13.
Any monomer is suitable to be used in a device described by the invention.
FY~mrles of suitable photoiniti~t~rs include Darocurs and Igacurs available from Merck UK such as Darocur 1173 or 4265 and Igacur 651. There are various UV curables which are available, some examples are Electrolite c~,~uldLion m~ft~ri~l~ such as ELC 4481 available through LlL~ .ol ics Ltd, Ki~llin~ton, Oxon.
Fx~rnl le 1 SCE13 +5%RLCl +~ O~ t~ly0.1%Darocur 1173.
Fx~m~I le ?
SCE8 + 1% RLCl + d~l~lv~ ely 0.1% Darocur 1173.
F.~m~rle 3 SCE8 + 0.5% RLCl + ~plul~illlately 0.1% Darocur 1173. Therm~lly ~ n~-l tmin against Vmjn plots were run for e~mrle 3.
For ~ mrle 3, one cell was cured a/ in the ~l~;st;llce of a d.c. field and another cell b/ was cured without the field. It was only for the cell cured without the presence of a field (3b) that electro-optic ~wilcl~il~g studies for example tmjn, Vmjn studies could be carried out on.
WO96/07123 219 8 7 ~ t; 12 PCT/GB95/02036 Figures 2-7 illustrate the appearance of liquid crystal cells viewed under a microsco~e before and after they had been subjected to merh~nir~l shock. Typically cells were 1.5-Z.O~lm thick for these ~ hllcnts, though cells of any suitable thic~n~ee could have been used.
For the examples contained in Figures 2-7, all of those that were cured were flow filled, therrn~lly cycled and cured in the Sc phase under a W lamp with no field applied. The initiator used was Darocur 1173 (~IJro?~illlately 0.1%).
Fx~mples were also tested wherein the m~teri~le were cured in the isotropic state after flow filling in the isotropic state.
Claims (8)
1. A liquid crystal device comprising two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, a layer of a smectic liquid crystal material enclosed between the cells walls, characterised in that the liquid crystal material contains an amount of polymer and the device exhibits a minimum in its response time verses voltage curve.
2. A liquid crystal device according to claim 1 wherein the polymer is a liquid crystal polymer.
3. A liquid crystal device according to claim 1 or 2 wherein the polymer is prepared by the in-situ polymerisation of a monomer
4. A liquid crystal device according to any of claims 1-3 wherein the polymer is present as a network.
5. A method of reducing the susceptibility of ferroelectric liquid crystal cells to impact damage comprising the steps of providing a liquid crystal device comprising two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, a layer of a smectic liquid crystal material enclosed between the cell walls, characterised in that the liquid crystal material contains an amount of polymer and the device exhibits a minimum in its response time verses voltage curve.
6. A method according to claim 5 wherein the ferroelectric liquid crystal cell is surface stabilised.
7. A device according to claim 5 wherein the polymer is a liquid crystal polymer.
8. A method of reducing the susceptibility of ferroelectric liquid crystal cells to impact damage comprising the steps of providing a liquid crystal device comprising two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, a layer comprising a polymer liquid crystal material and ferroelectric liquid crystal material enclosed between the cell walls characterised in that the polymer liquid crystal is prepared by the in-situ polymerisation of a monomer material and the device exhibits a minimum in its response time verses voltage curve.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9417480A GB9417480D0 (en) | 1994-08-31 | 1994-08-31 | Ferroelectric liquid crystal devices |
| GB9417480.2 | 1994-08-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2198716A1 true CA2198716A1 (en) | 1996-03-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002198716A Abandoned CA2198716A1 (en) | 1994-08-31 | 1995-08-30 | Ferroelectric liquid crystal devices |
Country Status (8)
| Country | Link |
|---|---|
| US (2) | US6075583A (en) |
| EP (1) | EP0778960B1 (en) |
| JP (1) | JPH10504914A (en) |
| KR (1) | KR100386381B1 (en) |
| CA (1) | CA2198716A1 (en) |
| DE (1) | DE69523609T2 (en) |
| GB (2) | GB9417480D0 (en) |
| WO (1) | WO1996007123A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| GB9417480D0 (en) * | 1994-08-31 | 1994-10-19 | Secr Defence | Ferroelectric liquid crystal devices |
| GB2308371B (en) * | 1994-10-13 | 1999-03-24 | Secr Defence | Liquid crystal polymer devices |
| DE69636766T2 (en) * | 1995-06-22 | 2007-10-18 | Sharp K.K. | Manufacturing method of a ferroelectric liquid crystal display device |
| US6118512A (en) * | 1995-12-27 | 2000-09-12 | Sharp Kabushiki Kaisha | Manufacturing method of a liquid crystal display element |
| TW400452B (en) * | 1995-12-27 | 2000-08-01 | Sharp Kk | Liquid crystal display element and a manufacturing method thereof as well as a liquid crystal display |
| GB9602919D0 (en) * | 1996-02-13 | 1996-04-10 | Univ Court Of Napier The Unive | Alignment technique |
| JPH09281528A (en) * | 1996-04-17 | 1997-10-31 | Sharp Corp | Ferroelectric liquid crystal element, its production and production of liquid crystal element |
| US6304304B1 (en) * | 1997-11-20 | 2001-10-16 | Sanyo Electric Co., Ltd. | Liquid crystal display having an off driving voltage greater than either zero or an optical characteristics changing voltage |
| GB9813839D0 (en) * | 1998-06-27 | 1998-08-26 | Sharp Kk | Ferroelectric liquid crystal devices |
| KR100751188B1 (en) * | 2000-12-30 | 2007-08-22 | 엘지.필립스 엘시디 주식회사 | Method of Fabricating Ferroelectric Liquid Crystal Display |
| KR100752505B1 (en) * | 2000-12-30 | 2007-08-28 | 엘지.필립스 엘시디 주식회사 | Ferroelectric Liquid Crystal Display |
| JP4342200B2 (en) * | 2002-06-06 | 2009-10-14 | シャープ株式会社 | Liquid crystal display |
| US8025937B2 (en) | 2006-04-17 | 2011-09-27 | Dow Corning Corporation | Bistable ferroelectric liquid crystal devices |
| FR2914755B1 (en) * | 2007-04-03 | 2009-12-04 | Groupe Ecoles Telecomm | METHOD FOR MANUFACTURING AN ELECTRO-OPTIC CELL BASED ON PSFLC AND / OR PSAFLC, ELECTRO-OPTIC CELL, DEVICE AND HELMET CORRESPONDING |
| KR101358328B1 (en) * | 2007-04-25 | 2014-02-06 | 삼성디스플레이 주식회사 | Liquid crystal display and method of fabricating the same |
| JP5552429B2 (en) | 2007-10-19 | 2014-07-16 | ダウ・コーニング・コーポレイション | Oligosiloxane-modified liquid crystal compound and device using the same |
| EP2217680B1 (en) | 2007-10-26 | 2011-11-30 | Dow Corning Corporation | Oligosiloxane modified liquid crystal formulations and devices using same |
| CL2011000198A1 (en) | 2011-01-31 | 2013-04-01 | Univ Chile | Polymerization process to obtain an electro-optical apparatus where the polymerization of a polymerizable compound occurs in situ, said polymer obtained in situ; the electro-optical apparatus containing said polymer; and uses of the device. |
| WO2016116040A1 (en) | 2015-01-20 | 2016-07-28 | The Hong Kong University Of Science And Technology | Standing helix ferroelectric liquid crystal display cell |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4367924A (en) * | 1980-01-08 | 1983-01-11 | Clark Noel A | Chiral smectic C or H liquid crystal electro-optical device |
| US4563059A (en) * | 1983-01-10 | 1986-01-07 | Clark Noel A | Surface stabilized ferroelectric liquid crystal devices |
| US5216530A (en) * | 1985-06-03 | 1993-06-01 | Taliq Corporation | Encapsulated liquid crystal having a smectic phase |
| GB8608114D0 (en) * | 1986-04-03 | 1986-05-08 | Secr Defence | Smectic liquid crystal devices |
| SI9210019A (en) * | 1992-01-10 | 1994-06-30 | Inst Jozef Stefan | Ferroelectric liquid crystal display cell, its method of manufacture and use |
| US5434685A (en) * | 1992-01-10 | 1995-07-18 | Kent State University | Ferroelectric liquid crystal cell, a method of making it, and its use |
| EP0586014B1 (en) * | 1992-09-01 | 1996-11-27 | Koninklijke Philips Electronics N.V. | Optical modulation device |
| GB9417480D0 (en) * | 1994-08-31 | 1994-10-19 | Secr Defence | Ferroelectric liquid crystal devices |
-
1994
- 1994-08-31 GB GB9417480A patent/GB9417480D0/en active Pending
-
1995
- 1995-08-30 WO PCT/GB1995/002036 patent/WO1996007123A1/en active IP Right Grant
- 1995-08-30 CA CA002198716A patent/CA2198716A1/en not_active Abandoned
- 1995-08-30 DE DE69523609T patent/DE69523609T2/en not_active Expired - Fee Related
- 1995-08-30 EP EP95929975A patent/EP0778960B1/en not_active Expired - Lifetime
- 1995-08-30 JP JP8508559A patent/JPH10504914A/en not_active Withdrawn
- 1995-08-30 GB GB9703203A patent/GB2306498B/en not_active Revoked
- 1995-08-30 US US08/793,527 patent/US6075583A/en not_active Expired - Lifetime
- 1995-08-30 KR KR1019970701304A patent/KR100386381B1/en not_active IP Right Cessation
-
2000
- 2000-03-01 US US09/516,192 patent/US6215543B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| KR970705775A (en) | 1997-10-09 |
| GB9703203D0 (en) | 1997-04-02 |
| DE69523609T2 (en) | 2002-07-11 |
| EP0778960A1 (en) | 1997-06-18 |
| KR100386381B1 (en) | 2003-08-19 |
| WO1996007123A1 (en) | 1996-03-07 |
| US6215543B1 (en) | 2001-04-10 |
| EP0778960B1 (en) | 2001-10-31 |
| GB2306498B (en) | 1999-03-24 |
| GB2306498A (en) | 1997-05-07 |
| US6075583A (en) | 2000-06-13 |
| JPH10504914A (en) | 1998-05-12 |
| DE69523609D1 (en) | 2001-12-06 |
| GB9417480D0 (en) | 1994-10-19 |
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