CA1312938C - Display device - Google Patents
Display deviceInfo
- Publication number
- CA1312938C CA1312938C CA000600750A CA600750A CA1312938C CA 1312938 C CA1312938 C CA 1312938C CA 000600750 A CA000600750 A CA 000600750A CA 600750 A CA600750 A CA 600750A CA 1312938 C CA1312938 C CA 1312938C
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- Canada
- Prior art keywords
- cell
- display region
- active display
- liquid crystal
- reservoir
- 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.)
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Abstract
ABSTRACT OF THE DISCLOSURE
A liquid crystal display cell comprises first and second substrates located in a substantially parallel relative arrangement to define an active display region therebetween when filled with liquid crystal material. The cell further includes means to effect filling of the active display region with liquid crystal material from at least a part of an edge of the active display region.
A liquid crystal display cell comprises first and second substrates located in a substantially parallel relative arrangement to define an active display region therebetween when filled with liquid crystal material. The cell further includes means to effect filling of the active display region with liquid crystal material from at least a part of an edge of the active display region.
Description
~ 3 ~
DISPLAY D~VIC~
The present invention relates to a liquld crystal device and to a method of filling such a liquid crystal device.
Host liquid crystal cells presently commercially available contain material~ that are in the nematic phase at room temperature, the cell spacing being typically of the order of 5 microns or more. As the liquid crystal materials are o~ lo~
viscosity, nematic cell~ can be qutckly and easily filled using standard vacuum backfilling techniques wherein the cell is evacuated in~ide a vacuu~ chamber, then one edge of the cell i8 lowered into a bath of the liquid crystal material 80 that the fill hole in that edge i8 fully immersed, and the vacuum chamber is then let up to at~osphere, the pres ure difference between the cell and surroundin~s ~orcing the materlal in~o the cell.
For a cell 8c~ square this ~y typically take 5 ~inutes at room temper~ture.
Certain other liquid crystal materials, which have great potential for high ~ultiplexability and a consequent capability for high information content di~plays, for exa~ple smectic liquid crystal materials (especially the ferroelectric smectic C
materials) have high viscosities compared with nematics.
Horeover the ferroelectric materials currently used require cell spacings of nominally 2 microns. Accordingly, the fllling rate o~ a cell by the convantional method is virtually ~ero at room temperature. ~he viscosity of the material can be reduced a certain amount by raising its temperature 80~ that it i~ in the nematic or isotropic phase~ but it8 Vi8c08ity at these : .
:
' 3 ~
: 2 temperature~ can still be hlgher than materlals us~d ln nematic devices. Indeed, lt can take over 1 hour to bac~fill a cell 8cm ~ 8cm and then there i8 uRually an area at tbe top of the cell which remains unfllled.
An ob~ect of the present invention ls to overcome the diff~cultles encountered by the prlor art.
one aspect of the present invention provlde~ a liquid crystal di~play cell comprising first and second substrates located ln a substantially parallel relative arrangement to define an active dlsplay region threbetween when filled with liquid crystal material, and means to effect filling of the active display region with liquid crystal materlal from at least a part of an edge of the active display region.
The lnventor has appreciated that one significant characteristic contributing to the difficultles encountered in the prior art ls the thin spacing between the sub~trates of the liquid crystal display cell and hence the s~all cross-sectional area of the fill-hole through which the liquid crystal material can flow. These difficulties are alleviated in the liquid crystal display cell provided in accordance with the pre~ent invention by the provision of ~eans to effect filllng of the active display region with liquid crystal material from at least a part of an edge of the actlve display region which increases the cross-sectional area into the active display region through which liquid crystal ~aterial can flow.
Preferably tbe filling means comprises a reservoir intermed~ate the first and second substrates, the reservoir having an outlet port which extends along at least a part of an edge of the active display region. This preferred embodiment is one arrangement by which the active display region can be filled from at least a part of its edge without the size of the fill hole being increased. In order for the situation to be improved by simply increaqing the size of the fill hole, the fill hole would need to be 3ubstantially the ~ize of the cell edge before any signiflcant improvement can be achieved; ~uch a ~qize of 4ill hole is wholly impractical because the cell ~ould then be " , , ~
~2~
unstable and liable to flexion, causlng thlckness non-unlformitles. ~oreover, lt would be dlfficult and undesirable to provlde a source of llquld crystal ~aterial whlch would be sufficiently large for a large fill hole but whlch would prevent gas or air entering the cell. ~n the preferred embodiment, the reservoir provides a large source of llquld crystal material lnternal to the cell from which the active dlsplay region may be fllled.
Preferably the reservolr has a width, in the dimension corresponding to the gap between the substrat~s in the active dlsplay region, much greater than the thickne~s of the gap.
Accordingly, the liquid crystal material can readily and guickly flow into the reservoir, and then on into the active display region.
The part of the reservoir having this greater width may be connected to the active display region by another part of narrower width. A3ternatively, in a preferred embodiment, the outlet port of the reservoir adjacent the active display region has this greater width.
Thus for example the outlet port may extend along substantially the whole of two sides of the active dlsplay region, thereby for~ing a shape generally similar to the capital letter L ~hen the cell is viewed in plan. In an alternative example, the outlet port may extend along substantially the whole of three side3 of the active display region, thereby forming a shape generally similar to the capital letter ~ when the cell ls viewed in plan. In another alternative example, the outlet port may extend sub~tantlally parallel to a diagonal of the cell.
Preferably, at least one of the substrates includes, on that side corresponding to the interior of the cell, a sectlon indented relative to the active displa~ region of the substrate, thereby to form the reservoir. Advantageously, the substrate has one or more layers to effect colour filtering for the cell in the active di~play region, this layering formlng or contributing to the stepped disposition between the active ~2~
~, display region and the indented sec~ion. Addltlonally or alternatively, the substrate(s) may compri~e a portlon which has been recessed (e.g. by milling, drllllng or etchlng) to form the re~ervolr.
Preferably, one of the sub~trates has an aperture effectlve as a flll hole ln communlcatlon wlth the reservolr.
Thls further reduces the risk of in~lexion.
Preferably the cell ~urther comprlses a vacuu~ hole. The advantages of a liquld crystal display cell provlded in accordance wlth the present invention are evident when the cell is filled by the back-filling technique. The provision of a vacuum hole allows a suction pressure to be applied while the cell is be~ng filled.
Preferably, the cell has a channel of an increased width, lS in the respective dimension, to the gap between the substrates in the active display region, the channel being in communication wlth the vacuum hole twhich is preferably disposed in one of the substrates) of the cell. The channel may be in a form corresponding to any of the structures for the reservoir.
While ~igures 6 and 7 of British Patent Specification No.1349921 show3 cells whose structures superficially appear similar to embodiments of the present invention, this document is concerned with ensurlng a lamlnar flow o~ the fluid Quspension over the active display region while there i8 continuous re-cycling ~umping of the suspension through the sy~tem. Neither the s~ze of the structure, nor the form of the suspensiQn, bears any practical or technical relation to the type of cell or liquid crystal material with which the present invention is concerned.
The present invention also provides a method of filling a liquid crystal display cell comprising fir3t and second substrates located in a substantially parallel relative arrangement to define an active display region therebetween when filled with liquid crystal material, the method co~prising fillinq the cell wlth liquid crystal material from at least a part of an edge of the active display region.
? ~ 3 $
In a preferred embodiment, the method lnclude3 flll1ng a reservoir intermediate the fitst and second substrate~, the reservoir having an outlet port which extends along at least part of an edge the active di~play region.
The present invention also embodies a cell produced by the filling method herein defined.
Another aspect of the present invention provides a liquid crystal display cell comprising two cell substrate3 for location in a substantially parallel relative arrange~ent to define an active display region therebetween when filled with liquid crystal material, and means to provide a filling front of llquld crystal material during filllng of the cell ~ith liquid crystal material, which filling front is not substantially parallel to a side of the cell and~or the active region thereof.
Thus for example the means to provide a non-parallel filling front may comprise any of the reservoirs deflned above. Additionally it may comprise an arrange~ent ~for example a reservoir) which provides non-unifora filllng along only one edge of the active display region, for example due to non central and/or assymetric positioning of a~y feed-hole(s).
In order that the invention may be more readll~ be understood, a descrlption is now glven, by wa~ of example only, reference being made to the accompanying drawing~, in which:-Figure 1 i8 a plan view of a liquid cry3tal cell embodying the present invention;
Figure 2 is a oross-sectional view along the line II-II of Figure 15 Figure 3 shows schematically a cell during the filling operation;
Figures 4 to 8 are schematic plan views of other cells embodying the present invention; and Figure 9 is a modification to the cell of Fiyure 1.
Figures 1 and 2 ~how a liquid crystal cell 1 (before filling) of dimensions 140mm x 140mm with a lo~er gla~s plate 2 haYing a serles of electrode layers and colour layer~
~de~ignated generally by reference numeral 3) ~hich define the : 6 : ~3~2~3~
active display region of the cell. An upper gla88 plate maintained parallel to the plate 2 at a Yeparation oi 7~m by means of an edge saal 5A along the entire perlphery o~ the cell and spacers 5B, such that the gap between layers 3 and plate 4 in the active display region is 2 ~m. Two block~ 6, formed of polymer or other appropriate material, are provlded to form two separate channels, one channel con~tituting a V-shaped reservolr 7 which communicates with a fill-hole 8 in plate 4 and the other channel constituting a vacuum channel 9 which communicate~ ~ith a vacuum hole 10 in plate 4. The width tas seen in plan ln Figure 1) of the reservoir 7 and vacuum channel 9 is 5 mm, and the polymer blocks 6 (as seen in plan in Figure 1) are 5 mm by 10 mm. The reservoir 7 has an outlet port 11 into the active display region of the cell.
To fill cell 1, approxi~ately 0~59 of smectic - c liguid crystal material is heated into its isotopic state and introduced throu~h a filling tube 12 into fill-hole B. A
vacuum is then applied to vacuum hole 10 ~see Figure 3).
Filling of cell 1 is achieved in about 45 minutes, this being appro~imately one third of the tlme that would be taken to fill a conventional cell with the 3ame active display region characteristics.
In a modification of the fllling operation, initially a low suction pressure i8 applied to vacuum-hole 10 while liquid crystal materlal is passing lnto the reservoir 7 and as it beginQ entering the active display region vla the lnlet port 11. Thereafter, the suction pressure applied to vacuum-hole 10 is varied in accordance with any increase in the distance from outlet port 11 to the filling front, thereby to ~aintain the flow rate; this can be readily achieved with good pumping equipment. In this way, effective filling of the active display area, with a minimi~ation or elimination of voids or bubbles, can be realised. The increase of pressure at the hole 8 as the cell fills can also maintain the speed of fill1ng front, this being particularly appropriate wbere the pumplng performance of eguipment is limited. A 3r~11 degree of ,. ','~
7 : ~ J ~ ? 8 bloatlng of the cell may occur, but thia can readily be eliminated by u~e of sub~equent appllcation of pre~sure to the outer surfaces of plates 2 and 4.
Thus, the cell 1 has an internal reservoir lnto which the material can readily flow, and the reservolr provides a large cross-sectional area outlet port from which the ~aterlal can flow while maintaining the structure of the cell rigid ~thereby reducing thickne~ non-uniformity problems). ~oreover, by filling the reservoir through a small hole, the likellhood of air entering the reservoir is reduced; if air does get into the cell, there i8 probably enough material in the reservoir to absorb it.
Moreover the filling operation of cell 1 provide~ a substantial reduction in the problem of void~ around metallisation strips in the cell; it is believed that this i3 due to the increased filling speed produced by reservoir 7.
Furthermore, the provision of vacuum channel 9 inhibits the progress of the filling front as it enters that channel and allows the parts of the front ~till progressinq through the ~0 active display reglon to catch up, thereby inhibiting the formation of void-R in the distribution of the liquid crystal interval in the active display reglon. additionally, the provision of reservoir 7 and vacuum channel 9 are able ~o accommodate any change in volume of the liquid crystal material when it cools down after the filling operation~ A180, the thickness of the reservoir 7 at vacuum channel 9 ls such that there is a very readily visible change in appearance of the material in the reservoir when it undergoes a phace change if the temperature reduce~ to the critical temperature where the material changes from its isotropic phase (a clear appearance) to the nematic (a milky appearance): accordingly, regular inspection of the material in the reservoir allows precl~e monitoring of the phase state of the material.
In a modification, there i8 provided either a ~loped or a stepped section at the edge o~ layer 3 to for~ a graduated interface between the layers 3 and reservolr 7 (rather than the , ~ .
DISPLAY D~VIC~
The present invention relates to a liquld crystal device and to a method of filling such a liquid crystal device.
Host liquid crystal cells presently commercially available contain material~ that are in the nematic phase at room temperature, the cell spacing being typically of the order of 5 microns or more. As the liquid crystal materials are o~ lo~
viscosity, nematic cell~ can be qutckly and easily filled using standard vacuum backfilling techniques wherein the cell is evacuated in~ide a vacuu~ chamber, then one edge of the cell i8 lowered into a bath of the liquid crystal material 80 that the fill hole in that edge i8 fully immersed, and the vacuum chamber is then let up to at~osphere, the pres ure difference between the cell and surroundin~s ~orcing the materlal in~o the cell.
For a cell 8c~ square this ~y typically take 5 ~inutes at room temper~ture.
Certain other liquid crystal materials, which have great potential for high ~ultiplexability and a consequent capability for high information content di~plays, for exa~ple smectic liquid crystal materials (especially the ferroelectric smectic C
materials) have high viscosities compared with nematics.
Horeover the ferroelectric materials currently used require cell spacings of nominally 2 microns. Accordingly, the fllling rate o~ a cell by the convantional method is virtually ~ero at room temperature. ~he viscosity of the material can be reduced a certain amount by raising its temperature 80~ that it i~ in the nematic or isotropic phase~ but it8 Vi8c08ity at these : .
:
' 3 ~
: 2 temperature~ can still be hlgher than materlals us~d ln nematic devices. Indeed, lt can take over 1 hour to bac~fill a cell 8cm ~ 8cm and then there i8 uRually an area at tbe top of the cell which remains unfllled.
An ob~ect of the present invention ls to overcome the diff~cultles encountered by the prlor art.
one aspect of the present invention provlde~ a liquid crystal di~play cell comprising first and second substrates located ln a substantially parallel relative arrangement to define an active dlsplay region threbetween when filled with liquid crystal material, and means to effect filling of the active display region with liquid crystal materlal from at least a part of an edge of the active display region.
The lnventor has appreciated that one significant characteristic contributing to the difficultles encountered in the prior art ls the thin spacing between the sub~trates of the liquid crystal display cell and hence the s~all cross-sectional area of the fill-hole through which the liquid crystal material can flow. These difficulties are alleviated in the liquid crystal display cell provided in accordance with the pre~ent invention by the provision of ~eans to effect filllng of the active display region with liquid crystal material from at least a part of an edge of the actlve display region which increases the cross-sectional area into the active display region through which liquid crystal ~aterial can flow.
Preferably tbe filling means comprises a reservoir intermed~ate the first and second substrates, the reservoir having an outlet port which extends along at least a part of an edge of the active display region. This preferred embodiment is one arrangement by which the active display region can be filled from at least a part of its edge without the size of the fill hole being increased. In order for the situation to be improved by simply increaqing the size of the fill hole, the fill hole would need to be 3ubstantially the ~ize of the cell edge before any signiflcant improvement can be achieved; ~uch a ~qize of 4ill hole is wholly impractical because the cell ~ould then be " , , ~
~2~
unstable and liable to flexion, causlng thlckness non-unlformitles. ~oreover, lt would be dlfficult and undesirable to provlde a source of llquld crystal ~aterial whlch would be sufficiently large for a large fill hole but whlch would prevent gas or air entering the cell. ~n the preferred embodiment, the reservoir provides a large source of llquld crystal material lnternal to the cell from which the active dlsplay region may be fllled.
Preferably the reservolr has a width, in the dimension corresponding to the gap between the substrat~s in the active dlsplay region, much greater than the thickne~s of the gap.
Accordingly, the liquid crystal material can readily and guickly flow into the reservoir, and then on into the active display region.
The part of the reservoir having this greater width may be connected to the active display region by another part of narrower width. A3ternatively, in a preferred embodiment, the outlet port of the reservoir adjacent the active display region has this greater width.
Thus for example the outlet port may extend along substantially the whole of two sides of the active dlsplay region, thereby for~ing a shape generally similar to the capital letter L ~hen the cell is viewed in plan. In an alternative example, the outlet port may extend along substantially the whole of three side3 of the active display region, thereby forming a shape generally similar to the capital letter ~ when the cell ls viewed in plan. In another alternative example, the outlet port may extend sub~tantlally parallel to a diagonal of the cell.
Preferably, at least one of the substrates includes, on that side corresponding to the interior of the cell, a sectlon indented relative to the active displa~ region of the substrate, thereby to form the reservoir. Advantageously, the substrate has one or more layers to effect colour filtering for the cell in the active di~play region, this layering formlng or contributing to the stepped disposition between the active ~2~
~, display region and the indented sec~ion. Addltlonally or alternatively, the substrate(s) may compri~e a portlon which has been recessed (e.g. by milling, drllllng or etchlng) to form the re~ervolr.
Preferably, one of the sub~trates has an aperture effectlve as a flll hole ln communlcatlon wlth the reservolr.
Thls further reduces the risk of in~lexion.
Preferably the cell ~urther comprlses a vacuu~ hole. The advantages of a liquld crystal display cell provlded in accordance wlth the present invention are evident when the cell is filled by the back-filling technique. The provision of a vacuum hole allows a suction pressure to be applied while the cell is be~ng filled.
Preferably, the cell has a channel of an increased width, lS in the respective dimension, to the gap between the substrates in the active display region, the channel being in communication wlth the vacuum hole twhich is preferably disposed in one of the substrates) of the cell. The channel may be in a form corresponding to any of the structures for the reservoir.
While ~igures 6 and 7 of British Patent Specification No.1349921 show3 cells whose structures superficially appear similar to embodiments of the present invention, this document is concerned with ensurlng a lamlnar flow o~ the fluid Quspension over the active display region while there i8 continuous re-cycling ~umping of the suspension through the sy~tem. Neither the s~ze of the structure, nor the form of the suspensiQn, bears any practical or technical relation to the type of cell or liquid crystal material with which the present invention is concerned.
The present invention also provides a method of filling a liquid crystal display cell comprising fir3t and second substrates located in a substantially parallel relative arrangement to define an active display region therebetween when filled with liquid crystal material, the method co~prising fillinq the cell wlth liquid crystal material from at least a part of an edge of the active display region.
? ~ 3 $
In a preferred embodiment, the method lnclude3 flll1ng a reservoir intermediate the fitst and second substrate~, the reservoir having an outlet port which extends along at least part of an edge the active di~play region.
The present invention also embodies a cell produced by the filling method herein defined.
Another aspect of the present invention provides a liquid crystal display cell comprising two cell substrate3 for location in a substantially parallel relative arrange~ent to define an active display region therebetween when filled with liquid crystal material, and means to provide a filling front of llquld crystal material during filllng of the cell ~ith liquid crystal material, which filling front is not substantially parallel to a side of the cell and~or the active region thereof.
Thus for example the means to provide a non-parallel filling front may comprise any of the reservoirs deflned above. Additionally it may comprise an arrange~ent ~for example a reservoir) which provides non-unifora filllng along only one edge of the active display region, for example due to non central and/or assymetric positioning of a~y feed-hole(s).
In order that the invention may be more readll~ be understood, a descrlption is now glven, by wa~ of example only, reference being made to the accompanying drawing~, in which:-Figure 1 i8 a plan view of a liquid cry3tal cell embodying the present invention;
Figure 2 is a oross-sectional view along the line II-II of Figure 15 Figure 3 shows schematically a cell during the filling operation;
Figures 4 to 8 are schematic plan views of other cells embodying the present invention; and Figure 9 is a modification to the cell of Fiyure 1.
Figures 1 and 2 ~how a liquid crystal cell 1 (before filling) of dimensions 140mm x 140mm with a lo~er gla~s plate 2 haYing a serles of electrode layers and colour layer~
~de~ignated generally by reference numeral 3) ~hich define the : 6 : ~3~2~3~
active display region of the cell. An upper gla88 plate maintained parallel to the plate 2 at a Yeparation oi 7~m by means of an edge saal 5A along the entire perlphery o~ the cell and spacers 5B, such that the gap between layers 3 and plate 4 in the active display region is 2 ~m. Two block~ 6, formed of polymer or other appropriate material, are provlded to form two separate channels, one channel con~tituting a V-shaped reservolr 7 which communicates with a fill-hole 8 in plate 4 and the other channel constituting a vacuum channel 9 which communicate~ ~ith a vacuum hole 10 in plate 4. The width tas seen in plan ln Figure 1) of the reservoir 7 and vacuum channel 9 is 5 mm, and the polymer blocks 6 (as seen in plan in Figure 1) are 5 mm by 10 mm. The reservoir 7 has an outlet port 11 into the active display region of the cell.
To fill cell 1, approxi~ately 0~59 of smectic - c liguid crystal material is heated into its isotopic state and introduced throu~h a filling tube 12 into fill-hole B. A
vacuum is then applied to vacuum hole 10 ~see Figure 3).
Filling of cell 1 is achieved in about 45 minutes, this being appro~imately one third of the tlme that would be taken to fill a conventional cell with the 3ame active display region characteristics.
In a modification of the fllling operation, initially a low suction pressure i8 applied to vacuum-hole 10 while liquid crystal materlal is passing lnto the reservoir 7 and as it beginQ entering the active display region vla the lnlet port 11. Thereafter, the suction pressure applied to vacuum-hole 10 is varied in accordance with any increase in the distance from outlet port 11 to the filling front, thereby to ~aintain the flow rate; this can be readily achieved with good pumping equipment. In this way, effective filling of the active display area, with a minimi~ation or elimination of voids or bubbles, can be realised. The increase of pressure at the hole 8 as the cell fills can also maintain the speed of fill1ng front, this being particularly appropriate wbere the pumplng performance of eguipment is limited. A 3r~11 degree of ,. ','~
7 : ~ J ~ ? 8 bloatlng of the cell may occur, but thia can readily be eliminated by u~e of sub~equent appllcation of pre~sure to the outer surfaces of plates 2 and 4.
Thus, the cell 1 has an internal reservoir lnto which the material can readily flow, and the reservolr provides a large cross-sectional area outlet port from which the ~aterlal can flow while maintaining the structure of the cell rigid ~thereby reducing thickne~ non-uniformity problems). ~oreover, by filling the reservoir through a small hole, the likellhood of air entering the reservoir is reduced; if air does get into the cell, there i8 probably enough material in the reservoir to absorb it.
Moreover the filling operation of cell 1 provide~ a substantial reduction in the problem of void~ around metallisation strips in the cell; it is believed that this i3 due to the increased filling speed produced by reservoir 7.
Furthermore, the provision of vacuum channel 9 inhibits the progress of the filling front as it enters that channel and allows the parts of the front ~till progressinq through the ~0 active display reglon to catch up, thereby inhibiting the formation of void-R in the distribution of the liquid crystal interval in the active display reglon. additionally, the provision of reservoir 7 and vacuum channel 9 are able ~o accommodate any change in volume of the liquid crystal material when it cools down after the filling operation~ A180, the thickness of the reservoir 7 at vacuum channel 9 ls such that there is a very readily visible change in appearance of the material in the reservoir when it undergoes a phace change if the temperature reduce~ to the critical temperature where the material changes from its isotropic phase (a clear appearance) to the nematic (a milky appearance): accordingly, regular inspection of the material in the reservoir allows precl~e monitoring of the phase state of the material.
In a modification, there i8 provided either a ~loped or a stepped section at the edge o~ layer 3 to for~ a graduated interface between the layers 3 and reservolr 7 (rather than the , ~ .
2 '', '~ J~3 a abrupt edge ~8 shown ln Flgure 1) thereby to enhance guiding of the materlal into the actlve di~play reglon.
Figure 4 8how8 schematically an alternatlve cell 20 embodying the present invention which differ~ from that of Figures 1 and 2 by having an L-shaped reservoir 21 whlch ex~ends along appeoximately half of two sides of the cell, a fill-hole 22 which i9 located at the centre of the L-shape and at a corner of the cell, and a vacuum hole 23 with no vacuum channel.
Figure 5 shows a modification wherein a cell 30 is rectanqular and the reservoir 31 i8 L-shaped, each arm correspondinq to approximately half the length of the appropriate side of the cell.
The cells 20 and 30 can be modified such that an arm of the reservoir extends along the appropriate side of th0 cell/active display region to a different degree, including the pos3ibility of extending along substantially the entire length of a side.
The shape and dimensions of the outlet port o~ the reRervoir affects the shape of the filling front produced, and thereby these parameter6 of the port are carefully chosen to fit to any given reguirements. Addit~onally or alternatively, the cells 20 and 30 may include a vacuum channel in si~ilar manner to channel 9 of cell l, and optionally the vacuum channel is of similar physlcal dimensions to the reservoirs 21 and 31.
Pigure 6 shows schematically another cell 40 embodying the present invention and having a reservoir 41 ~ith addltional branches 42 of various lengths.
Figure 7 shows schematically another cell 50 embodying the present inventlon and having a reservoir 51 which extends along a single side of the cell with a f~ hole 52 located at one end of the reservoir 51. Cell 50 has a vacuum channel 53 which extends along a single slde of the cell with a vacuum hole 54 at the end of channel 53 such as to be dia~etrically opposed to the fill-hole 52 with re~pect to the cell. The cell may be modified by positioning the fill-hole 52 or the vacuum hole 5~, or both, elsewhere alonq res-pectively the reservoir 51 and the channel 53~
. . .
.
:1 3 ~ 2 ~ i ~
Figure 8 shows schematically another cell 60 embodylng the present lnvention and having a reservolr Sl ~hich i8 triangular-shaped in plan with a ~lll-hole 62 ln the corner of the cell and a vacu-~m hole 63 ln the dlametrically opposlte corner of the cell.
Figure 9 .qhows a modificatlon to cell 1 (but which 1 equally appllcable to other embodiments of the present lnvention) wherein, before as~embly of cell 1, each of plates 2 and 4 are recessed (for example by milling or etching) to form grooves 70 and 71 respectlvely which in due cour~e contribute to formation of the re~ervolr. Likewise, one or both plates can be recessed to form the YaCUUm channel.
Any of the lllustrated Cell8 can be ~odified to provide a fill-hole and/or a vacuum hole along the edge of the cell.
Any of the ~llustrated cells can be modified such that the depth of the reservoir and/or the vacuum channel differs in order to control the fllling ~peed in different part~ of the cell.
.
., :
Figure 4 8how8 schematically an alternatlve cell 20 embodying the present invention which differ~ from that of Figures 1 and 2 by having an L-shaped reservoir 21 whlch ex~ends along appeoximately half of two sides of the cell, a fill-hole 22 which i9 located at the centre of the L-shape and at a corner of the cell, and a vacuum hole 23 with no vacuum channel.
Figure 5 shows a modification wherein a cell 30 is rectanqular and the reservoir 31 i8 L-shaped, each arm correspondinq to approximately half the length of the appropriate side of the cell.
The cells 20 and 30 can be modified such that an arm of the reservoir extends along the appropriate side of th0 cell/active display region to a different degree, including the pos3ibility of extending along substantially the entire length of a side.
The shape and dimensions of the outlet port o~ the reRervoir affects the shape of the filling front produced, and thereby these parameter6 of the port are carefully chosen to fit to any given reguirements. Addit~onally or alternatively, the cells 20 and 30 may include a vacuum channel in si~ilar manner to channel 9 of cell l, and optionally the vacuum channel is of similar physlcal dimensions to the reservoirs 21 and 31.
Pigure 6 shows schematically another cell 40 embodying the present invention and having a reservoir 41 ~ith addltional branches 42 of various lengths.
Figure 7 shows schematically another cell 50 embodying the present inventlon and having a reservoir 51 which extends along a single side of the cell with a f~ hole 52 located at one end of the reservoir 51. Cell 50 has a vacuum channel 53 which extends along a single slde of the cell with a vacuum hole 54 at the end of channel 53 such as to be dia~etrically opposed to the fill-hole 52 with re~pect to the cell. The cell may be modified by positioning the fill-hole 52 or the vacuum hole 5~, or both, elsewhere alonq res-pectively the reservoir 51 and the channel 53~
. . .
.
:1 3 ~ 2 ~ i ~
Figure 8 shows schematically another cell 60 embodylng the present lnvention and having a reservolr Sl ~hich i8 triangular-shaped in plan with a ~lll-hole 62 ln the corner of the cell and a vacu-~m hole 63 ln the dlametrically opposlte corner of the cell.
Figure 9 .qhows a modificatlon to cell 1 (but which 1 equally appllcable to other embodiments of the present lnvention) wherein, before as~embly of cell 1, each of plates 2 and 4 are recessed (for example by milling or etching) to form grooves 70 and 71 respectlvely which in due cour~e contribute to formation of the re~ervolr. Likewise, one or both plates can be recessed to form the YaCUUm channel.
Any of the lllustrated Cell8 can be ~odified to provide a fill-hole and/or a vacuum hole along the edge of the cell.
Any of the ~llustrated cells can be modified such that the depth of the reservoir and/or the vacuum channel differs in order to control the fllling ~peed in different part~ of the cell.
.
., :
Claims (12)
1. A cell for a liquid crystal display device, the cell comprising:
a first and a second substrate located in a substantially parallel relative arrangement to define an active display region therebetween which can be filled with liquid crystal material, said first and said second substrate being separated in the active display region by a gap having a gap thickness;
a reservoir for filling the active display region with liquid crystal material, the reservoir being positioned intermediate the first and said second substrates and having an outlet port which extends along at least a part of an edge of the active display region, and a vacuum channel for applying a suction pressure between the substrates and extending along at least a part of a further edge of the active display region, wherein the reservoir and the channel each have a width in the dimension corresponding to said gap thickness which is greater than said gap thickness.
a first and a second substrate located in a substantially parallel relative arrangement to define an active display region therebetween which can be filled with liquid crystal material, said first and said second substrate being separated in the active display region by a gap having a gap thickness;
a reservoir for filling the active display region with liquid crystal material, the reservoir being positioned intermediate the first and said second substrates and having an outlet port which extends along at least a part of an edge of the active display region, and a vacuum channel for applying a suction pressure between the substrates and extending along at least a part of a further edge of the active display region, wherein the reservoir and the channel each have a width in the dimension corresponding to said gap thickness which is greater than said gap thickness.
2 A cell according to claim 1 wherein said outlet port extends along at least a part of at least two edges of the active display region.
3. A cell according to claim 1 wherein the reservoir produces a filling front of liquid crystal material during filling of the cell with liquid crystal material, and the reservoir is adapted so that said filling front is not substantially parallel to a side of at least one of the cell or the active display region thereof.
4. A cell according to claim 1 wherein each substrate has an inner surface corresponding to the interior of the cell and at least one of the substrates includes at said : 11 :
inner surface a section indented relative to said inner surface at the active display region of the substrate, thereby to form the reservoir.
inner surface a section indented relative to said inner surface at the active display region of the substrate, thereby to form the reservoir.
5. A cell according to claim 4, wherein at least one of the substrates includes at said inner surface a section indented relative to said inner surface at the active display region of the substrate, thereby to form the channel.
6. A cell according to claim 4, said at least one of the substrates having at least one layer for colour filtering in the active display region wherein said at least one layer is positioned to at least contribute to said inner surface at the active display region and hence to the stepped disposition between the active display region and the indented section.
7. A cell according to claim 1 wherein one of the substrates has an aperture effective as a fill hole in communication with the reservoir.
8. A cell according to claim 1, wherein one of the substrates has an aperture effective as a Vacuum hole in communication with the channel.
9. A cell according to claim 1 when filled with liquid crystal material.
10. A method of filling a cell for a liquid crystal display device, the cell comprising:
a first and a second substrate located in a substantially parallel relative arrangement to define an active display region therebetween which can be filled with liquid crystal material, said first and said second substrate being separated in the active display region by a gap having a gap thickness;
: 12 :
a reservoir for filling the active display region with liquid crystal material, the reservoir being positioned intermediate said first and said second substrate and having an outlet port which extends along at least a part of an edge of the active display region, and a vacuum channel for applying a suction pressure between the substrates and extending along at least a part of a further edge of the active display region, wherein the reservoir and the channel each have a width in the dimension corresponding to said gap thickness which is greater than said gap thickness;
wherein the method includes the step of filling the reservoir with liquid crystal material and applying a suction pressure to the vacuum channel whereby to fill the cell with liquid crystal material from at least a part of an edge o the active display region.
a first and a second substrate located in a substantially parallel relative arrangement to define an active display region therebetween which can be filled with liquid crystal material, said first and said second substrate being separated in the active display region by a gap having a gap thickness;
: 12 :
a reservoir for filling the active display region with liquid crystal material, the reservoir being positioned intermediate said first and said second substrate and having an outlet port which extends along at least a part of an edge of the active display region, and a vacuum channel for applying a suction pressure between the substrates and extending along at least a part of a further edge of the active display region, wherein the reservoir and the channel each have a width in the dimension corresponding to said gap thickness which is greater than said gap thickness;
wherein the method includes the step of filling the reservoir with liquid crystal material and applying a suction pressure to the vacuum channel whereby to fill the cell with liquid crystal material from at least a part of an edge o the active display region.
11. A method according to claim 10 comprising filling the cell with liquid crystal material from at least a part of at least two edges of the active display region.
12. A method according to claim 10 including the step of varying the suction pressure applied to the vacuum channel whereby to control the rate at which the cell is filled.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000600750A CA1312938C (en) | 1989-05-25 | 1989-05-25 | Display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000600750A CA1312938C (en) | 1989-05-25 | 1989-05-25 | Display device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1312938C true CA1312938C (en) | 1993-01-19 |
Family
ID=4140103
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000600750A Expired - Fee Related CA1312938C (en) | 1989-05-25 | 1989-05-25 | Display device |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1312938C (en) |
-
1989
- 1989-05-25 CA CA000600750A patent/CA1312938C/en not_active Expired - Fee Related
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