Compound

Details Compound Compound

2002-01-09

2004-12-21

Zalukaeva, Tatyana (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S292100, C526S293000, C526S297000, C526S279000, C526S304000, C526S305000, C526S311000, C526S328000, C526S347000, C526S321000, C349S167000

Reexamination Certificate

active

06833421

ABSTRACT:

The present invention relates to new photoactive polymers, their use as liquid crystal (LC) orientation layers and their use in the construction of unstructured and structured optical and electro-optical elements and multi-layer systems.
The successful functioning of a Liquid Crystal Device relies upon the ability of the IC molecules within that device to assume and maintain an alignment imposed upon them. Alignment of the LC molecules is achieved by use of an orientation layer which defines a direction of orientation for the LC molecules of the device with the result that the longitudinal axes of the molecules become aligned with the direction of orientation defined by the orientation layer. In addition to this directional alignment, the orientation layer is also able to impart to the LC molecules an angle of tilt so that the molecules align themselves at an angle to the surface of the orientation layer rather than lying parallel thereto.
Tilt angles of between 1° and 15° are usual for Nematic LCDs. Tilt angles of about 7° are required for supertwisted nematic (STN) LCDs in order to avoid the formation of so-called fingerprint textures. Vertically aligned nematic (VAN) LCD's for instance require pretilt angles of between 85° and 90°.
Methods of preparing structured and unstructured orientation layers are well known to a skilled person. In particular it is known that by using linearly polarised light it is possible to prepare orientation layers in which both the direction of orientation and the tilt angle of the orientation layer are determined by the direction and angle of incidence of the plane polarised light used to irradiate said layer.
Structured orientation layers are of great interest in many areas of display technology and integrated optics. These layers are characterised by regions (pixels) which alternate in respect of the direction of orientation and angle of tilt of their component molecules. These orientation layers can be used to improve the viewing angle dependency of TN, STN and VAN LCDs, for example:
A possible method of producing high-resolution structured orientation patterns in liquid crystalline layers is described in
Jpn. J. Appl. Phys
., Vol. 31 (1992), 2155. In that process the dimerisation of polymer-bonded photoreactive cinnamic acid groups induced by irradiation with linearly polarised light is employed for the structured orientation of liquid crystals. Those photo-oriented polymer networks can be used wherever structured or unstructured liquid crystal orientation layers are required. In addition to their use in LCDs, these orientation layers can also be used, for example, in the production of so-called hybrid layers, as illustrated in European Patent Applications EP-A-0 611 981, EP-A-0 689 084 and EP-A-0 689 065. It is possible, using these hybrid layers of photostructured orientation polymers and crosslinkable low molecular weight liquid crystals to prepare optical elements such as, non-absorptive colour filters, linear and circular polarisers, optical delay layers and so on.
The ability of the resulting orientation layers to perform their function thus depends, in part, upon the number of molecules in the layer that have been dimerised as a result of irradiation with linearly polarised light. The extent to which the molecules are dimerised relies, in part, on the irradiation time, the irradiation energy and the structure of the molecules being irradiated.
EP-A-0 611 786, EP-A-0 763 552, EP-A-0 860 455, WO 96/10049 and WO 99/15576 describe polymers that are suitable in principle for the production of such anisotropically crosslinked, photostructured orientation layers for liquid crystals.
However, a problem with many polymers currently used in the preparation of photo-orientated orientation layers is that relatively long irradiation times are required to effect efficient dimerisation of the component molecules. There is, therefore, a need for photo crosslinkable polymers that can be readily cross-linked over a relatively short irradiation time. The present invention addresses that need.
A first aspect of the present invention provides a polymeric compound comprising a repeating unit of formula (I)
in which:
A represents a nitrogen atom, a carbon atom, a group —CR
1
— or an aromatic or alicyclic group, which is optionally substituted by a group selected from fluorine, chlorine, cyano and a C
1-18
cyclic, straight-chain or branched alkyl group, which is optionally substituted by a single cyano group or by one or more halogen atoms and in which one or more non-adjacent alkyl —CH
2
— groups are optionally replaced by a group selected from —O—, —CO—, —CO—O—, —O—CO—, —Si(CH
3
)
2
—O—Si(CH
3
)
2
—, —NR
1
—, —NR
1
—CO—, —CO—NR
1
—, —NR
1
—CO—O, —O—CO—NR
1
—, —NR
1
—CO—NR
1
—, —CH═CH—, —C≡C— and —O—CO—O—, wherein R
1
represents a hydrogen atom or lower alkyl,
M represents a repeating monomer unit;
n
1
to n
3
each independently represent 0 or an integer having a value of from 1 to 3, with the proviso that 1<n
1
+n
2
+n
3
<4;
P
1
, P
2
, P
3
each independently represents a photoactive group; and
B
1
to B
4
each independently represent a residue of general formula II
in which
S
1
to S
3
each independently represent a single bond or a spacer group selected from a C
1-24
straight-chain or branched alkylene group, which is optionally substituted by a single cyano group or by one or more halogen atoms and in which one or more non-adjacent alkylene —CH
2
— groups are optionally replaced by a group selected from —O—, —CO—, —CO—O—, —O—CO—, —Si(CH
3
)
2
—O—Si(CH
3
)
2
—, —NR
1
—, —NR
1
—CO—, —CO—NR
1
—, —NR
1
—CO—O—, —O—CO—NR
1
—, —NR
1
—CO—NR
1
—, —CH═CH—, —C≡C— and —O—CO—O— wherein R
1
is as defined above,
C
1
and C
2
each independently represents an aromatic or an alicyclic group, which is optionally substituted by a group selected from fluorine, chlorine, cyano or a C
1-18
cyclic, straight-chain or branched alkyl group, which is optionally substituted by a single cyano group or by one or more halogen atoms and in which one or more non-adjacent alkyl —CH
2
— groups are optionally replaced by a group selected from —CO—, —CO—, —CO—O—, —O—CO—, —Si(CH
3
)
2
—O—Si(CH
3
)
2
—, —NR
1
—, —NR
1
—CO—, —CO—NR
1
—, —NR
1
—CO—O—, —O—CO—NR
1
—, —NR
1
—CO—NR
1
—, —CH═CH—, —C≡C— and —O—CO—O— wherein R
1
represents a hydrogen atom or lower alkyl, and
n
4
and n
5
are each independently 0 or 1.
The polymeric compounds of the present invention can be readily aligned upon exposure to linearly polarised light. In addition, by using the compounds of the invention, it is possible to reduce the irradiation time required to form cross-linked polymer films.
By the term “aromatic” it should be understood to include optionally substituted carbocylic and heterocyclic groups.
By the term “cyclic, straight-chain or branched alkyl group, which is optionally substituted by a single cyano group or by one or more halogen atoms and in which one or more non-adjacent —CH
2
— groups are optionally replaced by a group selected from —O—, —CO—, —CO—O—, —O—CO—, —CH═CH— and —C≡C—,” it should be understood to include groups selected from the group comprising methyl, ethyl propyl, isopropyl, butyl, isobutyl, sec-butyl tert-butyl pentyl, isopentyl, cyclopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl 3-methylpentyl, allyl, but-3-en-1-yl, pent-4-en-1-yl, hex-5-en-1-yl, propynyl, butynyl, pentynyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, isopentyloxy, cyclopentyloxy, hexyloxy, cyclohexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, 3-methylpentyloxy, allyloxy, but-3-enyloxy, pent-4-enyloxy, cylohexylmethoxy, cyclopentylmethoxy, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, pentyloxycarbonyl, isopentyloxycarbonyl, cyclopentyloxycarbonyl, hexyloxycarbonyl, cyclohexyloxy, carbonyl, octyloxycarbonyl, nonyloxycarbonyl, decyloxycarbonyl

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