CA1089063A - Surface orientated liquid crystal display devices - Google Patents
Surface orientated liquid crystal display devicesInfo
- Publication number
- CA1089063A CA1089063A CA234,088A CA234088A CA1089063A CA 1089063 A CA1089063 A CA 1089063A CA 234088 A CA234088 A CA 234088A CA 1089063 A CA1089063 A CA 1089063A
- Authority
- CA
- Canada
- Prior art keywords
- liquid crystal
- electrodes
- supporting plates
- layer
- crystal material
- 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.)
- Expired
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
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
- G02F1/133711—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by organic films, e.g. polymeric films
Abstract
ABSTRACT:
A display device comprising a liquid crystal material between two supporting plates which have electrodes. The supporting plates and electrodes have a homogeneous soft layer of polyparaxylylene. Said layer has very fine parallel grooves to obtain a parallel orientation of the molecules of the liquid crystal material.
A display device comprising a liquid crystal material between two supporting plates which have electrodes. The supporting plates and electrodes have a homogeneous soft layer of polyparaxylylene. Said layer has very fine parallel grooves to obtain a parallel orientation of the molecules of the liquid crystal material.
Description
~Lg~g(36 3 PHN. 7681.
The invention relates to a display dev;ce comprising liquid crystal material between two supporting plates having electrodes9 which supporting plates and electrodes are covered with a homogeneous soft layer which has very fine parallel grooves to obtain a parallel orientation of the molecules of the liquid crystal material.
Such a display device is known from the Dutch pub-lished Patent Application 7,315,~05 by Siemens Aktiengesell-schaft which was filed on November 14, 1973 and laid open to -public inspection on May 20, 1974. However, the layers mentioned in said application do not satisfy all the require-ments to be imposed in practice.
It is the object of the invention to provide a material f~r the said layer which has very fine parallel grooves, which material satisfies excellently in nearly all respects. Experiments with a great variety of coat-ing layers have ultimately proved that, according to the invention, the soft layer in a display device of the kind ~;
mentioned in the first paragraph should be polyparaxylylene.
Excellent results have been obtained by evapora-ting the dimer diparaxylylene, which can be obtained, for example, under the trade name "Parylene" of Union Carbide, ~.
and splitting in vapour form by pyrolysis into reactive diradicals which upon deposition on the substrate poly-'"~
"', ',
The invention relates to a display dev;ce comprising liquid crystal material between two supporting plates having electrodes9 which supporting plates and electrodes are covered with a homogeneous soft layer which has very fine parallel grooves to obtain a parallel orientation of the molecules of the liquid crystal material.
Such a display device is known from the Dutch pub-lished Patent Application 7,315,~05 by Siemens Aktiengesell-schaft which was filed on November 14, 1973 and laid open to -public inspection on May 20, 1974. However, the layers mentioned in said application do not satisfy all the require-ments to be imposed in practice.
It is the object of the invention to provide a material f~r the said layer which has very fine parallel grooves, which material satisfies excellently in nearly all respects. Experiments with a great variety of coat-ing layers have ultimately proved that, according to the invention, the soft layer in a display device of the kind ~;
mentioned in the first paragraph should be polyparaxylylene.
Excellent results have been obtained by evapora-ting the dimer diparaxylylene, which can be obtained, for example, under the trade name "Parylene" of Union Carbide, ~.
and splitting in vapour form by pyrolysis into reactive diradicals which upon deposition on the substrate poly-'"~
"', ',
- 2 -A
~L~38~ 63 PHN. 7681.
merise to polyparaxylylene. Such a method is known from the United States Patent Specification 3,246,627, which issued on April 19, 1966 to Union Carbide Corporation5 and need not be described in detail.
A layer obtained in such a manner has a very even thickness and is optically uniform. The layer may be provided so as to be very thin, ~or example, thinner than 50 nm, which is necessary to prevent too large a voltage drop across the layer. The layer is so~t and can be provided with the parallel grooves in a simple manner by rubbing with, for example, paper which is used for cleaning lenses. When a polyparaxyly-lene layer is used, the surface of the supporting plates shows quite the same structure both at the area where the electrodes are present and at the area where no electrodes are present. Furthermore, the layer is very stable in properties and has a very high degree of poly-merisation. The interaction between the grooved layer and the liquid crystal is excellent, which results in a very good~parallel orientation of the molecules of the liquid crystal. This applies to all known nematic liquid crystals as well as to all cholesteric ones having a natural twist. Furthermore, the paraxylylene layer stimulates~the~adhesion between the supporting plates and a polyethyelene foil which is used for sealing the device and keeping the .
: : ''
~L~38~ 63 PHN. 7681.
merise to polyparaxylylene. Such a method is known from the United States Patent Specification 3,246,627, which issued on April 19, 1966 to Union Carbide Corporation5 and need not be described in detail.
A layer obtained in such a manner has a very even thickness and is optically uniform. The layer may be provided so as to be very thin, ~or example, thinner than 50 nm, which is necessary to prevent too large a voltage drop across the layer. The layer is so~t and can be provided with the parallel grooves in a simple manner by rubbing with, for example, paper which is used for cleaning lenses. When a polyparaxyly-lene layer is used, the surface of the supporting plates shows quite the same structure both at the area where the electrodes are present and at the area where no electrodes are present. Furthermore, the layer is very stable in properties and has a very high degree of poly-merisation. The interaction between the grooved layer and the liquid crystal is excellent, which results in a very good~parallel orientation of the molecules of the liquid crystal. This applies to all known nematic liquid crystals as well as to all cholesteric ones having a natural twist. Furthermore, the paraxylylene layer stimulates~the~adhesion between the supporting plates and a polyethyelene foil which is used for sealing the device and keeping the .
: : ''
- 3 - ;
- .
~,~, .
supporting plates spaced apart.
Moreover it has been found that in a device according to the invention the response rate is faster, an effect for which no satisfactory explanation can be given. The insulating paraxylylene layer furthermore protec~s the liquid crystal from decomposition by direct current.
The invention will be described in greater detail with reference to the accompanying drawing of a display device according to the invention.
The display device shown is manufactured as follows. Two glass plates 1 and 2 are provided in known manner with transparent electrodes 3, 4, 5 and 6 of tin oxide. The glass plates and the electrodes are then pro-, :;. .: .
vided with thin layers of polyparaxylene 7 and 8 as al-ready described above with reference to the United States ..
Patènt Specification 3,246,627. By rubbing with paper as is used for cleaning lenses, the Iayers 7 and g are pro-vided with microscopically fine parallel grooves. The provision of such grooves by rubbing is described in the article "Surface-produced alignment of liquid crystals"
in Proc. of the I.E.E.E., vol. 61, Nr. 7, July, 1973.
A spacing foil 9 of approximately 0.015 mm thick is then laid on the glass plate as well as a drop of liquid crys-tal, for example, p,p'-di-n-butylazoxybenzene, or briefly DIBAB. The glass plate 1 is then placed on the glass plate 2 with the spacing foil 9 and the liquid crystal 10 ..
-- 4 -- " .. .
~9 PHN 7681 and the display device is sealed by raising the tempera ture to approximately 150C for a few minutes so that the glass plates l and 2 adhere to the foil 9.
The elongate molecules of the liquid crystal 10 align in the grooves in the layers 7 and 8. This align-ment may be disturbed by applying a voltage of approxi-mately 10 Volts between the electrode 6 and one or more of the electrodes 3, 4 and 5 so as to display in known .
manner a given character. The electrodes 3, 4 and 5 may for that purpose ~orm part of a group of seven electrodes arranged in the form of a stylized digit eight.
.
. . ~ .
-- .
- .
~,~, .
supporting plates spaced apart.
Moreover it has been found that in a device according to the invention the response rate is faster, an effect for which no satisfactory explanation can be given. The insulating paraxylylene layer furthermore protec~s the liquid crystal from decomposition by direct current.
The invention will be described in greater detail with reference to the accompanying drawing of a display device according to the invention.
The display device shown is manufactured as follows. Two glass plates 1 and 2 are provided in known manner with transparent electrodes 3, 4, 5 and 6 of tin oxide. The glass plates and the electrodes are then pro-, :;. .: .
vided with thin layers of polyparaxylene 7 and 8 as al-ready described above with reference to the United States ..
Patènt Specification 3,246,627. By rubbing with paper as is used for cleaning lenses, the Iayers 7 and g are pro-vided with microscopically fine parallel grooves. The provision of such grooves by rubbing is described in the article "Surface-produced alignment of liquid crystals"
in Proc. of the I.E.E.E., vol. 61, Nr. 7, July, 1973.
A spacing foil 9 of approximately 0.015 mm thick is then laid on the glass plate as well as a drop of liquid crys-tal, for example, p,p'-di-n-butylazoxybenzene, or briefly DIBAB. The glass plate 1 is then placed on the glass plate 2 with the spacing foil 9 and the liquid crystal 10 ..
-- 4 -- " .. .
~9 PHN 7681 and the display device is sealed by raising the tempera ture to approximately 150C for a few minutes so that the glass plates l and 2 adhere to the foil 9.
The elongate molecules of the liquid crystal 10 align in the grooves in the layers 7 and 8. This align-ment may be disturbed by applying a voltage of approxi-mately 10 Volts between the electrode 6 and one or more of the electrodes 3, 4 and 5 so as to display in known .
manner a given character. The electrodes 3, 4 and 5 may for that purpose ~orm part of a group of seven electrodes arranged in the form of a stylized digit eight.
.
. . ~ .
-- .
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A display device comprising liquid crystal material having positive dielectric anisotropy between two supporting plates having electrodes, which supporting plates and electrodes are covered with a homogeneous soft layer which has very fine parallel grooves to obtain a parallel orientation of the mole-cules of the liquid crystal material, the parallel grooves in the layers on the respective supporting plates being mutually perpendicular, characterized in that the soft layer is polypar-axylylene.
2. A liquid crystal device of the torsion effect type comprising a cell of the structure comprising a pair of facing electrode plates and a nematic liquid crystal material having a positive dielectric anisotropy, which is inserted and sup-ported between said two electrode plates, wherein Facing ele-ctrode surfaces of said electrode plates coming into contact with the nematic liquid crystal layer are provided with a coat-ing of poly-p-xylylene, and the surface of said coating is fur-nished with a predetermined orientation.
3. A liquid crystal device of the torsion effect type as set forth in claim 2 wherein the coating is composed of a polymer layer formed on the electrode surface by thermal de-composition polymerization of di-p-xylylene.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7411138 | 1974-08-21 | ||
| NL7411138A NL162213C (en) | 1974-08-21 | 1974-08-21 | DISPLAY WITH LIQUID CRYSTAL. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1089063A true CA1089063A (en) | 1980-11-04 |
Family
ID=19821941
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA234,088A Expired CA1089063A (en) | 1974-08-21 | 1975-08-14 | Surface orientated liquid crystal display devices |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5145547A (en) |
| CA (1) | CA1089063A (en) |
| CH (1) | CH588712A5 (en) |
| DE (1) | DE2535674A1 (en) |
| FR (1) | FR2282651A1 (en) |
| NL (1) | NL162213C (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5733084B2 (en) * | 1973-11-20 | 1982-07-15 | ||
| NL7800584A (en) | 1978-01-18 | 1979-07-20 | Philips Nv | DISPLAY DEVICE. |
| JPS5548417A (en) * | 1978-09-30 | 1980-04-07 | Atsushi Oomasu | Tension travelling device of injection molding material |
| NL7906695A (en) * | 1979-09-07 | 1981-03-10 | Philips Nv | DISPLAY DEVICE. |
| EP0036923B1 (en) * | 1980-03-28 | 1984-01-18 | Contraves Ag | Liquid crystal display and method of making the same |
| JPH0866721A (en) * | 1994-08-31 | 1996-03-12 | Ohashi Kikai Kk | Drawing device for extruded material |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5120851A (en) * | 1974-06-29 | 1976-02-19 | Dainippon Toryo Kk | EKISHOSOSHI |
-
1974
- 1974-08-21 NL NL7411138A patent/NL162213C/en not_active IP Right Cessation
-
1975
- 1975-08-09 DE DE19752535674 patent/DE2535674A1/en not_active Ceased
- 1975-08-14 CA CA234,088A patent/CA1089063A/en not_active Expired
- 1975-08-18 JP JP9956875A patent/JPS5145547A/en active Pending
- 1975-08-18 CH CH1072575A patent/CH588712A5/xx not_active IP Right Cessation
- 1975-08-19 FR FR7525636A patent/FR2282651A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| DE2535674A1 (en) | 1976-03-04 |
| FR2282651A1 (en) | 1976-03-19 |
| CH588712A5 (en) | 1977-06-15 |
| NL162213B (en) | 1979-11-15 |
| NL7411138A (en) | 1976-02-24 |
| JPS5145547A (en) | 1976-04-19 |
| FR2282651B1 (en) | 1978-04-28 |
| NL162213C (en) | 1980-04-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |